1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra.
5 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>.
6 * Copyright 2009-2013 Konstantin Belousov <kib@FreeBSD.ORG>.
7 * Copyright 2012 John Marino <draco@marino.st>.
8 * Copyright 2014-2017 The FreeBSD Foundation
9 * All rights reserved.
10 *
11 * Portions of this software were developed by Konstantin Belousov
12 * under sponsorship from the FreeBSD Foundation.
13 *
14 * Redistribution and use in source and binary forms, with or without
15 * modification, are permitted provided that the following conditions
16 * are met:
17 * 1. Redistributions of source code must retain the above copyright
18 * notice, this list of conditions and the following disclaimer.
19 * 2. Redistributions in binary form must reproduce the above copyright
20 * notice, this list of conditions and the following disclaimer in the
21 * documentation and/or other materials provided with the distribution.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
26 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
33 */
34
35 /*
36 * Dynamic linker for ELF.
37 *
38 * John Polstra <jdp@polstra.com>.
39 */
40
41 #include <sys/param.h>
42 #include <sys/ktrace.h>
43 #include <sys/mman.h>
44 #include <sys/mount.h>
45 #include <sys/stat.h>
46 #include <sys/sysctl.h>
47 #include <sys/uio.h>
48 #include <sys/utsname.h>
49
50 #include <dlfcn.h>
51 #include <err.h>
52 #include <errno.h>
53 #include <fcntl.h>
54 #include <stdarg.h>
55 #include <stdio.h>
56 #include <stdlib.h>
57 #include <string.h>
58 #include <unistd.h>
59
60 #include "debug.h"
61 #include "libmap.h"
62 #include "notes.h"
63 #include "rtld.h"
64 #include "rtld_libc.h"
65 #include "rtld_malloc.h"
66 #include "rtld_paths.h"
67 #include "rtld_printf.h"
68 #include "rtld_tls.h"
69 #include "rtld_utrace.h"
70
71 /* Types. */
72 typedef void (*func_ptr_type)(void);
73 typedef void *(*path_enum_proc)(const char *path, size_t len, void *arg);
74
75 /* Variables that cannot be static: */
76 extern struct r_debug r_debug; /* For GDB */
77 extern int _thread_autoinit_dummy_decl;
78 extern void (*__cleanup)(void);
79
80 struct dlerror_save {
81 int seen;
82 char *msg;
83 };
84
85 struct tcb_list_entry {
86 TAILQ_ENTRY(tcb_list_entry) next;
87 };
88
89 /*
90 * Function declarations.
91 */
92 static bool allocate_tls_offset_common(size_t *offp, size_t tlssize,
93 size_t tlsalign, size_t tlspoffset);
94 static const char *basename(const char *);
95 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **,
96 const Elf_Dyn **, const Elf_Dyn **);
97 static bool digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *,
98 const Elf_Dyn *);
99 static bool digest_dynamic(Obj_Entry *, int);
100 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
101 static void distribute_static_tls(Objlist *);
102 static Obj_Entry *dlcheck(void *);
103 static int dlclose_locked(void *, RtldLockState *);
104 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj,
105 int lo_flags, int mode, RtldLockState *lockstate);
106 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int);
107 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *);
108 static bool donelist_check(DoneList *, const Obj_Entry *);
109 static void dump_auxv(Elf_Auxinfo **aux_info);
110 static void errmsg_restore(struct dlerror_save *);
111 static struct dlerror_save *errmsg_save(void);
112 static void *fill_search_info(const char *, size_t, void *);
113 static char *find_library(const char *, const Obj_Entry *, int *);
114 static const char *gethints(bool);
115 static void hold_object(Obj_Entry *);
116 static void unhold_object(Obj_Entry *);
117 static void init_dag(Obj_Entry *);
118 static void init_marker(Obj_Entry *);
119 static void init_pagesizes(Elf_Auxinfo **aux_info);
120 static void init_rtld(caddr_t, Elf_Auxinfo **);
121 static void initlist_add_neededs(Needed_Entry *, Objlist *, Objlist *);
122 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *,
123 Objlist *);
124 static void initlist_for_loaded_obj(Obj_Entry *obj, Obj_Entry *tail,
125 Objlist *list);
126 static int initlist_objects_ifunc(Objlist *, bool, int, RtldLockState *);
127 static void linkmap_add(Obj_Entry *);
128 static void linkmap_delete(Obj_Entry *);
129 static void load_filtees(Obj_Entry *, int flags, RtldLockState *);
130 static void unload_filtees(Obj_Entry *, RtldLockState *);
131 static int load_needed_objects(Obj_Entry *, int);
132 static int load_preload_objects(const char *, bool);
133 static int load_kpreload(const void *addr);
134 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int);
135 static void map_stacks_exec(RtldLockState *);
136 static int obj_disable_relro(Obj_Entry *);
137 static int obj_enforce_relro(Obj_Entry *);
138 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *);
139 static void objlist_call_init(Objlist *, RtldLockState *);
140 static void objlist_clear(Objlist *);
141 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
142 static void objlist_init(Objlist *);
143 static void objlist_push_head(Objlist *, Obj_Entry *);
144 static void objlist_push_tail(Objlist *, Obj_Entry *);
145 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *);
146 static void objlist_remove(Objlist *, Obj_Entry *);
147 static int open_binary_fd(const char *argv0, bool search_in_path,
148 const char **binpath_res);
149 static int parse_args(char *argv[], int argc, bool *use_pathp, int *fdp,
150 const char **argv0, bool *dir_ignore);
151 static int parse_integer(const char *);
152 static void *path_enumerate(const char *, path_enum_proc, const char *, void *);
153 static void print_usage(const char *argv0);
154 static void release_object(Obj_Entry *);
155 static int relocate_object_dag(Obj_Entry *root, bool bind_now,
156 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate);
157 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
158 int flags, RtldLockState *lockstate);
159 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int,
160 RtldLockState *);
161 static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *);
162 static int rtld_dirname(const char *, char *);
163 static int rtld_dirname_abs(const char *, char *);
164 static void *rtld_dlopen(const char *name, int fd, int mode);
165 static void rtld_exit(void);
166 static void rtld_nop_exit(void);
167 static char *search_library_path(const char *, const char *, const char *,
168 int *);
169 static char *search_library_pathfds(const char *, const char *, int *);
170 static const void **get_program_var_addr(const char *, RtldLockState *);
171 static void set_program_var(const char *, const void *);
172 static int symlook_default(SymLook *, const Obj_Entry *refobj);
173 static int symlook_global(SymLook *, DoneList *);
174 static void symlook_init_from_req(SymLook *, const SymLook *);
175 static int symlook_list(SymLook *, const Objlist *, DoneList *);
176 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *);
177 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *);
178 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *);
179 static void *tls_get_addr_slow(struct tcb *, int, size_t, bool) __noinline;
180 static void trace_loaded_objects(Obj_Entry *, bool);
181 static int try_fds_open(const char *name, const char *path);
182 static void unlink_object(Obj_Entry *);
183 static void unload_object(Obj_Entry *, RtldLockState *lockstate);
184 static void unref_dag(Obj_Entry *);
185 static void ref_dag(Obj_Entry *);
186 static char *origin_subst_one(Obj_Entry *, char *, const char *, const char *,
187 bool);
188 static char *origin_subst(Obj_Entry *, const char *);
189 static bool obj_resolve_origin(Obj_Entry *obj);
190 static void preinit_main(void);
191 static void rtld_recalc_bind_not(const char *);
192 static void rtld_recalc_dangerous_ld_env(void);
193 static void rtld_recalc_debug(const char *);
194 static void rtld_recalc_path_rpath(const char *);
195 static int rtld_verify_versions(const Objlist *);
196 static int rtld_verify_object_versions(Obj_Entry *);
197 static void object_add_name(Obj_Entry *, const char *);
198 static int object_match_name(const Obj_Entry *, const char *);
199 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
200 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
201 struct dl_phdr_info *phdr_info);
202 static uint32_t gnu_hash(const char *);
203 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *,
204 const unsigned long);
205
206 struct ld_env_var_desc;
207 static void rtld_set_var_bind_not(struct ld_env_var_desc *lvd);
208 static void rtld_set_var_bind_now(struct ld_env_var_desc *lvd);
209 static void rtld_set_var_debug(struct ld_env_var_desc *lvd);
210 static void rtld_set_var_dynamic_weak(struct ld_env_var_desc *lvd);
211 static void rtld_set_var_libmap_disable(struct ld_env_var_desc *lvd);
212 static void rtld_set_var_library_path(struct ld_env_var_desc *lvd);
213 static void rtld_set_var_library_path_fds(struct ld_env_var_desc *lvd);
214 static void rtld_set_var_library_path_rpath(struct ld_env_var_desc *lvd);
215 static void rtld_set_var_loadfltr(struct ld_env_var_desc *lvd);
216
217 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported;
218 void _r_debug_postinit(struct link_map *) __noinline __exported;
219
220 int __sys_openat(int, const char *, int, ...);
221
222 /*
223 * Data declarations.
224 */
225 struct r_debug r_debug __exported; /* for GDB; */
226 static bool libmap_disable; /* Disable libmap */
227 static bool ld_loadfltr; /* Immediate filters processing */
228 static const char *libmap_override; /* Maps to use in addition to libmap.conf */
229 static bool trust; /* False for setuid and setgid programs */
230 static bool dangerous_ld_env; /* True if environment variables have been
231 used to affect the libraries loaded */
232 bool ld_bind_not; /* Disable PLT update */
233 static const char *ld_bind_now; /* Environment variable for immediate binding */
234 static bool ld_dynamic_weak = true; /* True if non-weak definition overrides
235 weak definition */
236 static const char *ld_library_path; /* Environment variable for search path */
237 static const char
238 *ld_library_dirs; /* Environment variable for library descriptors */
239 static const char *ld_preload; /* Environment variable for libraries to
240 load first */
241 static const char *ld_preload_fds; /* Environment variable for libraries
242 represented by descriptors */
243 static const char
244 *ld_elf_hints_path; /* Environment variable for alternative hints path */
245 static const char *ld_tracing; /* Called from ldd to print libs */
246 static const char *ld_utrace; /* Use utrace() to log events. */
247 static struct obj_entry_q obj_list; /* Queue of all loaded objects */
248 static Obj_Entry *obj_main; /* The main program shared object */
249 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
250 static unsigned int obj_count; /* Number of objects in obj_list */
251 static unsigned int obj_loads; /* Number of loads of objects (gen count) */
252 size_t ld_static_tls_extra = /* Static TLS extra space (bytes) */
253 RTLD_STATIC_TLS_EXTRA;
254
255 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
256 STAILQ_HEAD_INITIALIZER(list_global);
257 static Objlist list_main = /* Objects loaded at program startup */
258 STAILQ_HEAD_INITIALIZER(list_main);
259 static Objlist list_fini = /* Objects needing fini() calls */
260 STAILQ_HEAD_INITIALIZER(list_fini);
261
262 Elf_Sym sym_zero; /* For resolving undefined weak refs. */
263
264 #define GDB_STATE(s, m) \
265 r_debug.r_state = s; \
266 r_debug_state(&r_debug, m);
267
268 extern Elf_Dyn _DYNAMIC;
269 #pragma weak _DYNAMIC
270
271 int dlclose(void *) __exported;
272 char *dlerror(void) __exported;
273 void *dlopen(const char *, int) __exported;
274 void *fdlopen(int, int) __exported;
275 void *dlsym(void *, const char *) __exported;
276 dlfunc_t dlfunc(void *, const char *) __exported;
277 void *dlvsym(void *, const char *, const char *) __exported;
278 int dladdr(const void *, Dl_info *) __exported;
279 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *),
280 void (*)(void *), void (*)(void *), void (*)(void *)) __exported;
281 int dlinfo(void *, int, void *) __exported;
282 int _dl_iterate_phdr_locked(__dl_iterate_hdr_callback, void *) __exported;
283 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported;
284 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported;
285 int _rtld_get_stack_prot(void) __exported;
286 int _rtld_is_dlopened(void *) __exported;
287 void _rtld_error(const char *, ...) __exported;
288 const char *rtld_get_var(const char *name) __exported;
289 int rtld_set_var(const char *name, const char *val) __exported;
290
291 /* Only here to fix -Wmissing-prototypes warnings */
292 int __getosreldate(void);
293 func_ptr_type _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp);
294 Elf_Addr _rtld_bind(Obj_Entry *obj, Elf_Size reloff);
295
296 int npagesizes;
297 static int osreldate;
298 size_t *pagesizes;
299 size_t page_size;
300
301 static int stack_prot = PROT_READ | PROT_WRITE | PROT_EXEC;
302 static int max_stack_flags;
303
304 /*
305 * Global declarations normally provided by crt1. The dynamic linker is
306 * not built with crt1, so we have to provide them ourselves.
307 */
308 char *__progname;
309 char **environ;
310
311 /*
312 * Used to pass argc, argv to init functions.
313 */
314 int main_argc;
315 char **main_argv;
316
317 /*
318 * Globals to control TLS allocation.
319 */
320 size_t tls_last_offset; /* Static TLS offset of last module */
321 size_t tls_last_size; /* Static TLS size of last module */
322 size_t tls_static_space; /* Static TLS space allocated */
323 static size_t tls_static_max_align;
324 Elf_Addr tls_dtv_generation = 1; /* Used to detect when dtv size changes */
325 int tls_max_index = 1; /* Largest module index allocated */
326
327 static TAILQ_HEAD(, tcb_list_entry) tcb_list =
328 TAILQ_HEAD_INITIALIZER(tcb_list);
329 static size_t tcb_list_entry_offset;
330
331 static bool ld_library_path_rpath = false;
332 bool ld_fast_sigblock = false;
333
334 /*
335 * Globals for path names, and such
336 */
337 const char *ld_elf_hints_default = _PATH_ELF_HINTS;
338 const char *ld_path_libmap_conf = _PATH_LIBMAP_CONF;
339 const char *ld_path_rtld = _PATH_RTLD;
340 const char *ld_standard_library_path = STANDARD_LIBRARY_PATH;
341 const char *ld_env_prefix = LD_;
342
343 static void (*rtld_exit_ptr)(void);
344
345 #define LD_UTRACE(e, h, mb, ms, r, n) \
346 do { \
347 if (ld_utrace != NULL) \
348 ld_utrace_log(e, h, mb, ms, r, n); \
349 } while (0)
350
351 static void
ld_utrace_log(int event,void * handle,void * mapbase,size_t mapsize,int refcnt,const char * name)352 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
353 int refcnt, const char *name)
354 {
355 struct utrace_rtld ut;
356 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] __nonstring =
357 RTLD_UTRACE_SIG;
358
359 memset(&ut, 0, sizeof(ut)); /* clear holes */
360 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig));
361 ut.event = event;
362 ut.handle = handle;
363 ut.mapbase = mapbase;
364 ut.mapsize = mapsize;
365 ut.refcnt = refcnt;
366 if (name != NULL)
367 strlcpy(ut.name, name, sizeof(ut.name));
368 utrace(&ut, sizeof(ut));
369 }
370
371 struct ld_env_var_desc {
372 const char *const n;
373 const char *val;
374 const bool unsecure : 1;
375 const bool can_update : 1;
376 bool owned : 1;
377 void (*const on_update)(struct ld_env_var_desc *);
378 };
379 #define LD_ENV_DESC(var, unsec, ...) \
380 [LD_##var] = { .n = #var, .unsecure = unsec, __VA_ARGS__ }
381
382 static struct ld_env_var_desc ld_env_vars[] = {
383 LD_ENV_DESC(BIND_NOW, false, .can_update = true,
384 .on_update = rtld_set_var_bind_now),
385 LD_ENV_DESC(PRELOAD, true),
386 LD_ENV_DESC(LIBMAP, true),
387 LD_ENV_DESC(LIBRARY_PATH, true, .can_update = true,
388 .on_update = rtld_set_var_library_path),
389 LD_ENV_DESC(LIBRARY_PATH_FDS, true, .can_update = true,
390 .on_update = rtld_set_var_library_path_fds),
391 LD_ENV_DESC(LIBMAP_DISABLE, true, .can_update = true,
392 .on_update = rtld_set_var_libmap_disable),
393 LD_ENV_DESC(BIND_NOT, true, .can_update = true,
394 .on_update = rtld_set_var_bind_not),
395 LD_ENV_DESC(DEBUG, true, .can_update = true,
396 .on_update = rtld_set_var_debug),
397 LD_ENV_DESC(ELF_HINTS_PATH, true),
398 LD_ENV_DESC(LOADFLTR, true, .can_update = true,
399 .on_update = rtld_set_var_loadfltr),
400 LD_ENV_DESC(LIBRARY_PATH_RPATH, true, .can_update = true,
401 .on_update = rtld_set_var_library_path_rpath),
402 LD_ENV_DESC(PRELOAD_FDS, true),
403 LD_ENV_DESC(DYNAMIC_WEAK, true, .can_update = true,
404 .on_update = rtld_set_var_dynamic_weak),
405 LD_ENV_DESC(TRACE_LOADED_OBJECTS, false),
406 LD_ENV_DESC(UTRACE, false, .can_update = true),
407 LD_ENV_DESC(DUMP_REL_PRE, false, .can_update = true),
408 LD_ENV_DESC(DUMP_REL_POST, false, .can_update = true),
409 LD_ENV_DESC(TRACE_LOADED_OBJECTS_PROGNAME, false),
410 LD_ENV_DESC(TRACE_LOADED_OBJECTS_FMT1, false),
411 LD_ENV_DESC(TRACE_LOADED_OBJECTS_FMT2, false),
412 LD_ENV_DESC(TRACE_LOADED_OBJECTS_ALL, false),
413 LD_ENV_DESC(SHOW_AUXV, true),
414 LD_ENV_DESC(STATIC_TLS_EXTRA, false),
415 LD_ENV_DESC(NO_DL_ITERATE_PHDR_AFTER_FORK, false),
416 };
417
418 const char *
ld_get_env_var(int idx)419 ld_get_env_var(int idx)
420 {
421 return (ld_env_vars[idx].val);
422 }
423
424 static const char *
rtld_get_env_val(char ** env,const char * name,size_t name_len)425 rtld_get_env_val(char **env, const char *name, size_t name_len)
426 {
427 char **m, *n, *v;
428
429 for (m = env; *m != NULL; m++) {
430 n = *m;
431 v = strchr(n, '=');
432 if (v == NULL) {
433 /* corrupt environment? */
434 continue;
435 }
436 if (v - n == (ptrdiff_t)name_len &&
437 strncmp(name, n, name_len) == 0)
438 return (v + 1);
439 }
440 return (NULL);
441 }
442
443 static void
rtld_init_env_vars_for_prefix(char ** env,const char * env_prefix)444 rtld_init_env_vars_for_prefix(char **env, const char *env_prefix)
445 {
446 struct ld_env_var_desc *lvd;
447 size_t prefix_len, nlen;
448 char **m, *n, *v;
449 int i;
450
451 prefix_len = strlen(env_prefix);
452 for (m = env; *m != NULL; m++) {
453 n = *m;
454 if (strncmp(env_prefix, n, prefix_len) != 0) {
455 /* Not a rtld environment variable. */
456 continue;
457 }
458 n += prefix_len;
459 v = strchr(n, '=');
460 if (v == NULL) {
461 /* corrupt environment? */
462 continue;
463 }
464 for (i = 0; i < (int)nitems(ld_env_vars); i++) {
465 lvd = &ld_env_vars[i];
466 if (lvd->val != NULL) {
467 /* Saw higher-priority variable name already. */
468 continue;
469 }
470 nlen = strlen(lvd->n);
471 if (v - n == (ptrdiff_t)nlen &&
472 strncmp(lvd->n, n, nlen) == 0) {
473 lvd->val = v + 1;
474 break;
475 }
476 }
477 }
478 }
479
480 static void
rtld_init_env_vars(char ** env)481 rtld_init_env_vars(char **env)
482 {
483 rtld_init_env_vars_for_prefix(env, ld_env_prefix);
484 }
485
486 static void
set_ld_elf_hints_path(void)487 set_ld_elf_hints_path(void)
488 {
489 if (ld_elf_hints_path == NULL || strlen(ld_elf_hints_path) == 0)
490 ld_elf_hints_path = ld_elf_hints_default;
491 }
492
493 uintptr_t
rtld_round_page(uintptr_t x)494 rtld_round_page(uintptr_t x)
495 {
496 return (roundup2(x, page_size));
497 }
498
499 uintptr_t
rtld_trunc_page(uintptr_t x)500 rtld_trunc_page(uintptr_t x)
501 {
502 return (rounddown2(x, page_size));
503 }
504
505 /*
506 * Main entry point for dynamic linking. The first argument is the
507 * stack pointer. The stack is expected to be laid out as described
508 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
509 * Specifically, the stack pointer points to a word containing
510 * ARGC. Following that in the stack is a null-terminated sequence
511 * of pointers to argument strings. Then comes a null-terminated
512 * sequence of pointers to environment strings. Finally, there is a
513 * sequence of "auxiliary vector" entries.
514 *
515 * The second argument points to a place to store the dynamic linker's
516 * exit procedure pointer and the third to a place to store the main
517 * program's object.
518 *
519 * The return value is the main program's entry point.
520 */
521 func_ptr_type
_rtld(Elf_Addr * sp,func_ptr_type * exit_proc,Obj_Entry ** objp)522 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
523 {
524 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT], auxtmp;
525 Objlist_Entry *entry;
526 Obj_Entry *last_interposer, *obj, *preload_tail;
527 const Elf_Phdr *phdr;
528 Objlist initlist;
529 RtldLockState lockstate;
530 struct stat st;
531 Elf_Addr *argcp;
532 char **argv, **env, **envp, *kexecpath;
533 const char *argv0, *binpath, *static_tls_extra;
534 struct ld_env_var_desc *lvd;
535 caddr_t imgentry;
536 char buf[MAXPATHLEN];
537 int argc, fd, i, mib[4], old_osrel, osrel, phnum, rtld_argc;
538 size_t sz;
539 bool dir_enable, dir_ignore, direct_exec, explicit_fd, search_in_path;
540
541 /*
542 * On entry, the dynamic linker itself has not been relocated yet.
543 * Be very careful not to reference any global data until after
544 * init_rtld has returned. It is OK to reference file-scope statics
545 * and string constants, and to call static and global functions.
546 */
547
548 /* Find the auxiliary vector on the stack. */
549 argcp = sp;
550 argc = *sp++;
551 argv = (char **)sp;
552 sp += argc + 1; /* Skip over arguments and NULL terminator */
553 env = (char **)sp;
554 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
555 ;
556 aux = (Elf_Auxinfo *)sp;
557
558 /* Digest the auxiliary vector. */
559 for (i = 0; i < AT_COUNT; i++)
560 aux_info[i] = NULL;
561 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
562 if (auxp->a_type < AT_COUNT)
563 aux_info[auxp->a_type] = auxp;
564 }
565 arch_fix_auxv(aux, aux_info);
566
567 /* Initialize and relocate ourselves. */
568 assert(aux_info[AT_BASE] != NULL);
569 init_rtld((caddr_t)aux_info[AT_BASE]->a_un.a_ptr, aux_info);
570
571 dlerror_dflt_init();
572
573 __progname = obj_rtld.path;
574 argv0 = argv[0] != NULL ? argv[0] : "(null)";
575 environ = env;
576 main_argc = argc;
577 main_argv = argv;
578
579 if (aux_info[AT_BSDFLAGS] != NULL &&
580 (aux_info[AT_BSDFLAGS]->a_un.a_val & ELF_BSDF_SIGFASTBLK) != 0)
581 ld_fast_sigblock = true;
582
583 trust = !issetugid();
584 direct_exec = false;
585
586 md_abi_variant_hook(aux_info);
587 rtld_init_env_vars(env);
588
589 fd = -1;
590 if (aux_info[AT_EXECFD] != NULL) {
591 fd = aux_info[AT_EXECFD]->a_un.a_val;
592 } else {
593 assert(aux_info[AT_PHDR] != NULL);
594 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr;
595 if (phdr == obj_rtld.phdr) {
596 if (!trust) {
597 _rtld_error(
598 "Tainted process refusing to run binary %s",
599 argv0);
600 rtld_die();
601 }
602 direct_exec = true;
603
604 dbg("opening main program in direct exec mode");
605 if (argc >= 2) {
606 rtld_argc = parse_args(argv, argc,
607 &search_in_path, &fd, &argv0, &dir_ignore);
608 explicit_fd = (fd != -1);
609 binpath = NULL;
610 if (!explicit_fd)
611 fd = open_binary_fd(argv0,
612 search_in_path, &binpath);
613 if (fstat(fd, &st) == -1) {
614 _rtld_error(
615 "Failed to fstat FD %d (%s): %s",
616 fd,
617 explicit_fd ?
618 "user-provided descriptor" :
619 argv0,
620 rtld_strerror(errno));
621 rtld_die();
622 }
623
624 /*
625 * Rough emulation of the permission checks done
626 * by execve(2), only Unix DACs are checked,
627 * ACLs are ignored. Preserve the semantic of
628 * disabling owner to execute if owner x bit is
629 * cleared, even if others x bit is enabled.
630 * mmap(2) does not allow to mmap with PROT_EXEC
631 * if binary' file comes from noexec mount. We
632 * cannot set a text reference on the binary.
633 */
634 dir_enable = false;
635 if (st.st_uid == geteuid()) {
636 if ((st.st_mode & S_IXUSR) != 0)
637 dir_enable = true;
638 } else if (st.st_gid == getegid()) {
639 if ((st.st_mode & S_IXGRP) != 0)
640 dir_enable = true;
641 } else if ((st.st_mode & S_IXOTH) != 0) {
642 dir_enable = true;
643 }
644 if (!dir_enable && !dir_ignore) {
645 _rtld_error(
646 "No execute permission for binary %s",
647 argv0);
648 rtld_die();
649 }
650
651 /*
652 * For direct exec mode, argv[0] is the
653 * interpreter name, we must remove it and shift
654 * arguments left before invoking binary main.
655 * Since stack layout places environment
656 * pointers and aux vectors right after the
657 * terminating NULL, we must shift environment
658 * and aux as well.
659 */
660 main_argc = argc - rtld_argc;
661 for (i = 0; i <= main_argc; i++)
662 argv[i] = argv[i + rtld_argc];
663 *argcp -= rtld_argc;
664 environ = env = envp = argv + main_argc + 1;
665 dbg("move env from %p to %p", envp + rtld_argc,
666 envp);
667 do {
668 *envp = *(envp + rtld_argc);
669 } while (*envp++ != NULL);
670 aux = auxp = (Elf_Auxinfo *)envp;
671 auxpf = (Elf_Auxinfo *)(envp + rtld_argc);
672 dbg("move aux from %p to %p", auxpf, aux);
673 /*
674 * XXXKIB insert place for AT_EXECPATH if not
675 * present
676 */
677 for (;; auxp++, auxpf++) {
678 /*
679 * NB: Use a temporary since *auxpf and
680 * *auxp overlap if rtld_argc is 1
681 */
682 auxtmp = *auxpf;
683 *auxp = auxtmp;
684 if (auxp->a_type == AT_NULL)
685 break;
686 }
687 /*
688 * Since the auxiliary vector has moved,
689 * redigest it.
690 */
691 for (i = 0; i < AT_COUNT; i++)
692 aux_info[i] = NULL;
693 for (auxp = aux; auxp->a_type != AT_NULL;
694 auxp++) {
695 if (auxp->a_type < AT_COUNT)
696 aux_info[auxp->a_type] = auxp;
697 }
698
699 /*
700 * Point AT_EXECPATH auxv and aux_info to the
701 * binary path.
702 */
703 if (binpath == NULL) {
704 aux_info[AT_EXECPATH] = NULL;
705 } else {
706 if (aux_info[AT_EXECPATH] == NULL) {
707 aux_info[AT_EXECPATH] = xmalloc(
708 sizeof(Elf_Auxinfo));
709 aux_info[AT_EXECPATH]->a_type =
710 AT_EXECPATH;
711 }
712 aux_info[AT_EXECPATH]->a_un.a_ptr =
713 __DECONST(void *, binpath);
714 }
715 } else {
716 _rtld_error("No binary");
717 rtld_die();
718 }
719 }
720 }
721
722 ld_bind_now = ld_get_env_var(LD_BIND_NOW);
723
724 /*
725 * If the process is tainted, then we un-set the dangerous environment
726 * variables. The process will be marked as tainted until setuid(2)
727 * is called. If any child process calls setuid(2) we do not want any
728 * future processes to honor the potentially un-safe variables.
729 */
730 if (!trust) {
731 for (i = 0; i < (int)nitems(ld_env_vars); i++) {
732 lvd = &ld_env_vars[i];
733 if (lvd->unsecure)
734 lvd->val = NULL;
735 }
736 }
737
738 rtld_recalc_debug(ld_get_env_var(LD_DEBUG));
739 rtld_recalc_bind_not(ld_get_env_var(LD_BIND_NOT));
740 ld_dynamic_weak = ld_get_env_var(LD_DYNAMIC_WEAK) == NULL;
741 libmap_disable = ld_get_env_var(LD_LIBMAP_DISABLE) != NULL;
742 libmap_override = ld_get_env_var(LD_LIBMAP);
743 ld_library_path = ld_get_env_var(LD_LIBRARY_PATH);
744 ld_library_dirs = ld_get_env_var(LD_LIBRARY_PATH_FDS);
745 ld_preload = ld_get_env_var(LD_PRELOAD);
746 ld_preload_fds = ld_get_env_var(LD_PRELOAD_FDS);
747 ld_elf_hints_path = ld_get_env_var(LD_ELF_HINTS_PATH);
748 ld_loadfltr = ld_get_env_var(LD_LOADFLTR) != NULL;
749 rtld_recalc_path_rpath(ld_get_env_var(LD_LIBRARY_PATH_RPATH));
750 static_tls_extra = ld_get_env_var(LD_STATIC_TLS_EXTRA);
751 if (static_tls_extra != NULL && static_tls_extra[0] != '\0') {
752 sz = parse_integer(static_tls_extra);
753 if (sz >= RTLD_STATIC_TLS_EXTRA && sz <= SIZE_T_MAX)
754 ld_static_tls_extra = sz;
755 }
756 rtld_recalc_dangerous_ld_env();
757 ld_tracing = ld_get_env_var(LD_TRACE_LOADED_OBJECTS);
758 ld_utrace = ld_get_env_var(LD_UTRACE);
759
760 set_ld_elf_hints_path();
761 dbg("%s is initialized, base address = %p", __progname,
762 (caddr_t)aux_info[AT_BASE]->a_un.a_ptr);
763 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
764 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
765
766 dbg("initializing thread locks");
767 lockdflt_init();
768
769 /*
770 * Load the main program, or process its program header if it is
771 * already loaded.
772 */
773 if (fd != -1) { /* Load the main program. */
774 dbg("loading main program");
775 obj_main = map_object(fd, argv0, NULL, true);
776 close(fd);
777 if (obj_main == NULL)
778 rtld_die();
779 max_stack_flags = obj_main->stack_flags;
780 } else { /* Main program already loaded. */
781 dbg("processing main program's program header");
782 assert(aux_info[AT_PHDR] != NULL);
783 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr;
784 assert(aux_info[AT_PHNUM] != NULL);
785 phnum = aux_info[AT_PHNUM]->a_un.a_val;
786 assert(aux_info[AT_PHENT] != NULL);
787 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
788 assert(aux_info[AT_ENTRY] != NULL);
789 imgentry = (caddr_t)aux_info[AT_ENTRY]->a_un.a_ptr;
790 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) ==
791 NULL)
792 rtld_die();
793 }
794
795 if (aux_info[AT_EXECPATH] != NULL && fd == -1) {
796 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
797 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
798 if (kexecpath[0] == '/')
799 obj_main->path = kexecpath;
800 else if (getcwd(buf, sizeof(buf)) == NULL ||
801 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
802 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
803 obj_main->path = xstrdup(argv0);
804 else
805 obj_main->path = xstrdup(buf);
806 } else {
807 dbg("No AT_EXECPATH or direct exec");
808 obj_main->path = xstrdup(argv0);
809 }
810 dbg("obj_main path %s", obj_main->path);
811 obj_main->mainprog = true;
812
813 if (aux_info[AT_STACKPROT] != NULL &&
814 aux_info[AT_STACKPROT]->a_un.a_val != 0)
815 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
816
817 #ifndef COMPAT_libcompat
818 /*
819 * Get the actual dynamic linker pathname from the executable if
820 * possible. (It should always be possible.) That ensures that
821 * gdb will find the right dynamic linker even if a non-standard
822 * one is being used.
823 */
824 if (obj_main->interp != NULL &&
825 strcmp(obj_main->interp, obj_rtld.path) != 0) {
826 free(obj_rtld.path);
827 obj_rtld.path = xstrdup(obj_main->interp);
828 __progname = obj_rtld.path;
829 }
830 #endif
831
832 if (!digest_dynamic(obj_main, 0))
833 rtld_die();
834 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d",
835 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu,
836 obj_main->dynsymcount);
837
838 linkmap_add(obj_main);
839 linkmap_add(&obj_rtld);
840 LD_UTRACE(UTRACE_LOAD_OBJECT, obj_main, obj_main->mapbase,
841 obj_main->mapsize, 0, obj_main->path);
842 LD_UTRACE(UTRACE_LOAD_OBJECT, &obj_rtld, obj_rtld.mapbase,
843 obj_rtld.mapsize, 0, obj_rtld.path);
844
845 /* Link the main program into the list of objects. */
846 TAILQ_INSERT_HEAD(&obj_list, obj_main, next);
847 obj_count++;
848 obj_loads++;
849
850 /* Initialize a fake symbol for resolving undefined weak references. */
851 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
852 sym_zero.st_shndx = SHN_UNDEF;
853 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
854
855 if (!libmap_disable)
856 libmap_disable = (bool)lm_init(libmap_override);
857
858 if (aux_info[AT_KPRELOAD] != NULL &&
859 aux_info[AT_KPRELOAD]->a_un.a_ptr != NULL) {
860 dbg("loading kernel vdso");
861 if (load_kpreload(aux_info[AT_KPRELOAD]->a_un.a_ptr) == -1)
862 rtld_die();
863 }
864
865 dbg("loading LD_PRELOAD_FDS libraries");
866 if (load_preload_objects(ld_preload_fds, true) == -1)
867 rtld_die();
868
869 dbg("loading LD_PRELOAD libraries");
870 if (load_preload_objects(ld_preload, false) == -1)
871 rtld_die();
872 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q));
873
874 dbg("loading needed objects");
875 if (load_needed_objects(obj_main,
876 ld_tracing != NULL ? RTLD_LO_TRACE : 0) == -1)
877 rtld_die();
878
879 /* Make a list of all objects loaded at startup. */
880 last_interposer = obj_main;
881 TAILQ_FOREACH(obj, &obj_list, next) {
882 if (obj->marker)
883 continue;
884 if (obj->z_interpose && obj != obj_main) {
885 objlist_put_after(&list_main, last_interposer, obj);
886 last_interposer = obj;
887 } else {
888 objlist_push_tail(&list_main, obj);
889 }
890 obj->refcount++;
891 }
892
893 dbg("checking for required versions");
894 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
895 rtld_die();
896
897 if (ld_get_env_var(LD_SHOW_AUXV) != NULL)
898 dump_auxv(aux_info);
899
900 if (ld_tracing) { /* We're done */
901 trace_loaded_objects(obj_main, true);
902 exit(0);
903 }
904
905 if (ld_get_env_var(LD_DUMP_REL_PRE) != NULL) {
906 dump_relocations(obj_main);
907 exit(0);
908 }
909
910 /*
911 * Processing tls relocations requires having the tls offsets
912 * initialized. Prepare offsets before starting initial
913 * relocation processing.
914 */
915 dbg("initializing initial thread local storage offsets");
916 STAILQ_FOREACH(entry, &list_main, link) {
917 /*
918 * Allocate all the initial objects out of the static TLS
919 * block even if they didn't ask for it.
920 */
921 allocate_tls_offset(entry->obj);
922 }
923
924 if (!allocate_tls_offset_common(&tcb_list_entry_offset,
925 sizeof(struct tcb_list_entry), _Alignof(struct tcb_list_entry),
926 0)) {
927 /*
928 * This should be impossible as the static block size is not
929 * yet fixed, but catch and diagnose it failing if that ever
930 * changes or somehow turns out to be false.
931 */
932 _rtld_error("Could not allocate offset for tcb_list_entry");
933 rtld_die();
934 }
935 dbg("tcb_list_entry_offset %zu", tcb_list_entry_offset);
936
937 if (relocate_objects(obj_main,
938 ld_bind_now != NULL && *ld_bind_now != '\0', &obj_rtld,
939 SYMLOOK_EARLY, NULL) == -1)
940 rtld_die();
941
942 dbg("doing copy relocations");
943 if (do_copy_relocations(obj_main) == -1)
944 rtld_die();
945
946 if (ld_get_env_var(LD_DUMP_REL_POST) != NULL) {
947 dump_relocations(obj_main);
948 exit(0);
949 }
950
951 ifunc_init(aux_info);
952
953 /*
954 * Setup TLS for main thread. This must be done after the
955 * relocations are processed, since tls initialization section
956 * might be the subject for relocations.
957 */
958 dbg("initializing initial thread local storage");
959 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list)));
960
961 dbg("initializing key program variables");
962 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
963 set_program_var("environ", env);
964 set_program_var("__elf_aux_vector", aux);
965
966 /* Make a list of init functions to call. */
967 objlist_init(&initlist);
968 initlist_for_loaded_obj(globallist_curr(TAILQ_FIRST(&obj_list)),
969 preload_tail, &initlist);
970
971 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
972
973 map_stacks_exec(NULL);
974
975 if (!obj_main->crt_no_init) {
976 /*
977 * Make sure we don't call the main program's init and fini
978 * functions for binaries linked with old crt1 which calls
979 * _init itself.
980 */
981 obj_main->init = obj_main->fini = 0;
982 obj_main->preinit_array = obj_main->init_array =
983 obj_main->fini_array = NULL;
984 }
985
986 if (direct_exec) {
987 /* Set osrel for direct-execed binary */
988 mib[0] = CTL_KERN;
989 mib[1] = KERN_PROC;
990 mib[2] = KERN_PROC_OSREL;
991 mib[3] = getpid();
992 osrel = obj_main->osrel;
993 sz = sizeof(old_osrel);
994 dbg("setting osrel to %d", osrel);
995 (void)sysctl(mib, 4, &old_osrel, &sz, &osrel, sizeof(osrel));
996 }
997
998 wlock_acquire(rtld_bind_lock, &lockstate);
999
1000 dbg("resolving ifuncs");
1001 if (initlist_objects_ifunc(&initlist,
1002 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY,
1003 &lockstate) == -1)
1004 rtld_die();
1005
1006 rtld_exit_ptr = rtld_exit;
1007 if (obj_main->crt_no_init)
1008 preinit_main();
1009 objlist_call_init(&initlist, &lockstate);
1010 _r_debug_postinit(&obj_main->linkmap);
1011 objlist_clear(&initlist);
1012 dbg("loading filtees");
1013 TAILQ_FOREACH(obj, &obj_list, next) {
1014 if (obj->marker)
1015 continue;
1016 if (ld_loadfltr || obj->z_loadfltr)
1017 load_filtees(obj, 0, &lockstate);
1018 }
1019
1020 dbg("enforcing main obj relro");
1021 if (obj_enforce_relro(obj_main) == -1)
1022 rtld_die();
1023
1024 lock_release(rtld_bind_lock, &lockstate);
1025
1026 dbg("transferring control to program entry point = %p",
1027 obj_main->entry);
1028
1029 /* Return the exit procedure and the program entry point. */
1030 *exit_proc = rtld_exit_ptr;
1031 *objp = obj_main;
1032 return ((func_ptr_type)obj_main->entry);
1033 }
1034
1035 /*
1036 * Fill in a DoneList with an allocation large enough to hold all of
1037 * the currently-loaded Keep this as a macro since it calls
1038 * alloca and we want that to occur within the scope of the caller.
1039 */
1040 #define DLP_ALLOCA_LIMIT 100 /* 800 bytes on LP64 */
1041 #define donelist_init(_DLP, _REQ) do { \
1042 DoneList *_dlp = _DLP; \
1043 SymLook *_r = _REQ; \
1044 _dlp->num_alloc = obj_count, \
1045 _dlp->req = NULL; \
1046 if (_dlp->num_alloc > DLP_ALLOCA_LIMIT) { \
1047 _dlp->objs = xcalloc(_dlp->num_alloc, sizeof(_dlp->objs[0])); \
1048 if (_r != NULL && _r->donelist_mem == NULL) { \
1049 _r->donelist_mem = _dlp->objs; \
1050 _dlp->req = _r; \
1051 } \
1052 } else { \
1053 _dlp->objs = alloca(_dlp->num_alloc * sizeof(_dlp->objs[0])); \
1054 } \
1055 _dlp->num_used = 0; \
1056 } while (0)
1057
1058 static void
donelist_free(DoneList * dlp)1059 donelist_free(DoneList *dlp)
1060 {
1061 if (dlp->num_alloc > DLP_ALLOCA_LIMIT)
1062 free(dlp->objs);
1063 if (dlp->req != NULL)
1064 dlp->req->donelist_mem = NULL;
1065 }
1066
1067 void *
rtld_resolve_ifunc(const Obj_Entry * obj,const Elf_Sym * def)1068 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
1069 {
1070 void *ptr;
1071 Elf_Addr target;
1072
1073 ptr = (void *)make_function_pointer(def, obj);
1074 target = call_ifunc_resolver(ptr);
1075 return ((void *)target);
1076 }
1077
1078 Elf_Addr
_rtld_bind(Obj_Entry * obj,Elf_Size reloff)1079 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
1080 {
1081 const Elf_Rel *rel;
1082 const Elf_Sym *def;
1083 const Obj_Entry *defobj;
1084 Elf_Addr *where;
1085 Elf_Addr target;
1086 RtldLockState lockstate;
1087
1088 relock:
1089 rlock_acquire(rtld_bind_lock, &lockstate);
1090 if (sigsetjmp(lockstate.env, 0) != 0)
1091 lock_upgrade(rtld_bind_lock, &lockstate);
1092 if (obj->pltrel)
1093 rel = (const Elf_Rel *)((const char *)obj->pltrel + reloff);
1094 else
1095 rel = (const Elf_Rel *)((const char *)obj->pltrela + reloff);
1096
1097 where = (Elf_Addr *)(obj->relocbase + rel->r_offset);
1098 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT,
1099 NULL, &lockstate);
1100 if (def == NULL)
1101 rtld_die();
1102 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) {
1103 if (lockstate_wlocked(&lockstate)) {
1104 lock_release(rtld_bind_lock, &lockstate);
1105 goto relock;
1106 }
1107 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
1108 } else {
1109 target = (Elf_Addr)(defobj->relocbase + def->st_value);
1110 }
1111
1112 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", defobj->strtab + def->st_name,
1113 obj->path == NULL ? NULL : basename(obj->path), (void *)target,
1114 defobj->path == NULL ? NULL : basename(defobj->path));
1115
1116 /*
1117 * Write the new contents for the jmpslot. Note that depending on
1118 * architecture, the value which we need to return back to the
1119 * lazy binding trampoline may or may not be the target
1120 * address. The value returned from reloc_jmpslot() is the value
1121 * that the trampoline needs.
1122 */
1123 target = reloc_jmpslot(where, target, defobj, obj, rel);
1124 lock_release(rtld_bind_lock, &lockstate);
1125 return (target);
1126 }
1127
1128 /*
1129 * Error reporting function. Use it like printf. If formats the message
1130 * into a buffer, and sets things up so that the next call to dlerror()
1131 * will return the message.
1132 */
1133 void
_rtld_error(const char * fmt,...)1134 _rtld_error(const char *fmt, ...)
1135 {
1136 va_list ap;
1137
1138 va_start(ap, fmt);
1139 rtld_vsnprintf(lockinfo.dlerror_loc(), lockinfo.dlerror_loc_sz, fmt,
1140 ap);
1141 va_end(ap);
1142 *lockinfo.dlerror_seen() = 0;
1143 dbg("rtld_error: %s", lockinfo.dlerror_loc());
1144 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, lockinfo.dlerror_loc());
1145 }
1146
1147 /*
1148 * Return a dynamically-allocated copy of the current error message, if any.
1149 */
1150 static struct dlerror_save *
errmsg_save(void)1151 errmsg_save(void)
1152 {
1153 struct dlerror_save *res;
1154
1155 res = xmalloc(sizeof(*res));
1156 res->seen = *lockinfo.dlerror_seen();
1157 if (res->seen == 0)
1158 res->msg = xstrdup(lockinfo.dlerror_loc());
1159 return (res);
1160 }
1161
1162 /*
1163 * Restore the current error message from a copy which was previously saved
1164 * by errmsg_save(). The copy is freed.
1165 */
1166 static void
errmsg_restore(struct dlerror_save * saved_msg)1167 errmsg_restore(struct dlerror_save *saved_msg)
1168 {
1169 if (saved_msg == NULL || saved_msg->seen == 1) {
1170 *lockinfo.dlerror_seen() = 1;
1171 } else {
1172 *lockinfo.dlerror_seen() = 0;
1173 strlcpy(lockinfo.dlerror_loc(), saved_msg->msg,
1174 lockinfo.dlerror_loc_sz);
1175 free(saved_msg->msg);
1176 }
1177 free(saved_msg);
1178 }
1179
1180 static const char *
basename(const char * name)1181 basename(const char *name)
1182 {
1183 const char *p;
1184
1185 p = strrchr(name, '/');
1186 return (p != NULL ? p + 1 : name);
1187 }
1188
1189 static struct utsname uts;
1190
1191 static char *
origin_subst_one(Obj_Entry * obj,char * real,const char * kw,const char * subst,bool may_free)1192 origin_subst_one(Obj_Entry *obj, char *real, const char *kw, const char *subst,
1193 bool may_free)
1194 {
1195 char *p, *p1, *res, *resp;
1196 int subst_len, kw_len, subst_count, old_len, new_len;
1197
1198 kw_len = strlen(kw);
1199
1200 /*
1201 * First, count the number of the keyword occurrences, to
1202 * preallocate the final string.
1203 */
1204 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) {
1205 p1 = strstr(p, kw);
1206 if (p1 == NULL)
1207 break;
1208 }
1209
1210 /*
1211 * If the keyword is not found, just return.
1212 *
1213 * Return non-substituted string if resolution failed. We
1214 * cannot do anything more reasonable, the failure mode of the
1215 * caller is unresolved library anyway.
1216 */
1217 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj)))
1218 return (may_free ? real : xstrdup(real));
1219 if (obj != NULL)
1220 subst = obj->origin_path;
1221
1222 /*
1223 * There is indeed something to substitute. Calculate the
1224 * length of the resulting string, and allocate it.
1225 */
1226 subst_len = strlen(subst);
1227 old_len = strlen(real);
1228 new_len = old_len + (subst_len - kw_len) * subst_count;
1229 res = xmalloc(new_len + 1);
1230
1231 /*
1232 * Now, execute the substitution loop.
1233 */
1234 for (p = real, resp = res, *resp = '\0';;) {
1235 p1 = strstr(p, kw);
1236 if (p1 != NULL) {
1237 /* Copy the prefix before keyword. */
1238 memcpy(resp, p, p1 - p);
1239 resp += p1 - p;
1240 /* Keyword replacement. */
1241 memcpy(resp, subst, subst_len);
1242 resp += subst_len;
1243 *resp = '\0';
1244 p = p1 + kw_len;
1245 } else
1246 break;
1247 }
1248
1249 /* Copy to the end of string and finish. */
1250 strcat(resp, p);
1251 if (may_free)
1252 free(real);
1253 return (res);
1254 }
1255
1256 static const struct {
1257 const char *kw;
1258 bool pass_obj;
1259 const char *subst;
1260 } tokens[] = {
1261 { .kw = "$ORIGIN", .pass_obj = true, .subst = NULL },
1262 { .kw = "${ORIGIN}", .pass_obj = true, .subst = NULL },
1263 { .kw = "$OSNAME", .pass_obj = false, .subst = uts.sysname },
1264 { .kw = "${OSNAME}", .pass_obj = false, .subst = uts.sysname },
1265 { .kw = "$OSREL", .pass_obj = false, .subst = uts.release },
1266 { .kw = "${OSREL}", .pass_obj = false, .subst = uts.release },
1267 { .kw = "$PLATFORM", .pass_obj = false, .subst = uts.machine },
1268 { .kw = "${PLATFORM}", .pass_obj = false, .subst = uts.machine },
1269 { .kw = "$LIB", .pass_obj = false, .subst = TOKEN_LIB },
1270 { .kw = "${LIB}", .pass_obj = false, .subst = TOKEN_LIB },
1271 };
1272
1273 static char *
origin_subst(Obj_Entry * obj,const char * real)1274 origin_subst(Obj_Entry *obj, const char *real)
1275 {
1276 char *res;
1277 int i;
1278
1279 if (obj == NULL || !trust)
1280 return (xstrdup(real));
1281 if (uts.sysname[0] == '\0') {
1282 if (uname(&uts) != 0) {
1283 _rtld_error("utsname failed: %d", errno);
1284 return (NULL);
1285 }
1286 }
1287
1288 /* __DECONST is safe here since without may_free real is unchanged */
1289 res = __DECONST(char *, real);
1290 for (i = 0; i < (int)nitems(tokens); i++) {
1291 res = origin_subst_one(tokens[i].pass_obj ? obj : NULL, res,
1292 tokens[i].kw, tokens[i].subst, i != 0);
1293 }
1294 return (res);
1295 }
1296
1297 void
rtld_die(void)1298 rtld_die(void)
1299 {
1300 const char *msg = dlerror();
1301
1302 if (msg == NULL)
1303 msg = "Fatal error";
1304 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": ");
1305 rtld_fdputstr(STDERR_FILENO, msg);
1306 rtld_fdputchar(STDERR_FILENO, '\n');
1307 _exit(1);
1308 }
1309
1310 /*
1311 * Process a shared object's DYNAMIC section, and save the important
1312 * information in its Obj_Entry structure.
1313 */
1314 static void
digest_dynamic1(Obj_Entry * obj,int early,const Elf_Dyn ** dyn_rpath,const Elf_Dyn ** dyn_soname,const Elf_Dyn ** dyn_runpath)1315 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
1316 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath)
1317 {
1318 const Elf_Dyn *dynp;
1319 Needed_Entry **needed_tail = &obj->needed;
1320 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
1321 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
1322 const Elf_Hashelt *hashtab;
1323 const Elf32_Word *hashval;
1324 Elf32_Word bkt, nmaskwords;
1325 int bloom_size32;
1326 int plttype = DT_REL;
1327
1328 *dyn_rpath = NULL;
1329 *dyn_soname = NULL;
1330 *dyn_runpath = NULL;
1331
1332 obj->bind_now = false;
1333 dynp = obj->dynamic;
1334 if (dynp == NULL)
1335 return;
1336 for (; dynp->d_tag != DT_NULL; dynp++) {
1337 switch (dynp->d_tag) {
1338 case DT_REL:
1339 obj->rel = (const Elf_Rel *)(obj->relocbase +
1340 dynp->d_un.d_ptr);
1341 break;
1342
1343 case DT_RELSZ:
1344 obj->relsize = dynp->d_un.d_val;
1345 break;
1346
1347 case DT_RELENT:
1348 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
1349 break;
1350
1351 case DT_JMPREL:
1352 obj->pltrel = (const Elf_Rel *)(obj->relocbase +
1353 dynp->d_un.d_ptr);
1354 break;
1355
1356 case DT_PLTRELSZ:
1357 obj->pltrelsize = dynp->d_un.d_val;
1358 break;
1359
1360 case DT_RELA:
1361 obj->rela = (const Elf_Rela *)(obj->relocbase +
1362 dynp->d_un.d_ptr);
1363 break;
1364
1365 case DT_RELASZ:
1366 obj->relasize = dynp->d_un.d_val;
1367 break;
1368
1369 case DT_RELAENT:
1370 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
1371 break;
1372
1373 case DT_RELR:
1374 obj->relr = (const Elf_Relr *)(obj->relocbase +
1375 dynp->d_un.d_ptr);
1376 break;
1377
1378 case DT_RELRSZ:
1379 obj->relrsize = dynp->d_un.d_val;
1380 break;
1381
1382 case DT_RELRENT:
1383 assert(dynp->d_un.d_val == sizeof(Elf_Relr));
1384 break;
1385
1386 case DT_PLTREL:
1387 plttype = dynp->d_un.d_val;
1388 assert(
1389 dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
1390 break;
1391
1392 case DT_SYMTAB:
1393 obj->symtab = (const Elf_Sym *)(obj->relocbase +
1394 dynp->d_un.d_ptr);
1395 break;
1396
1397 case DT_SYMENT:
1398 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
1399 break;
1400
1401 case DT_STRTAB:
1402 obj->strtab = (const char *)(obj->relocbase +
1403 dynp->d_un.d_ptr);
1404 break;
1405
1406 case DT_STRSZ:
1407 obj->strsize = dynp->d_un.d_val;
1408 break;
1409
1410 case DT_VERNEED:
1411 obj->verneed = (const Elf_Verneed *)(obj->relocbase +
1412 dynp->d_un.d_val);
1413 break;
1414
1415 case DT_VERNEEDNUM:
1416 obj->verneednum = dynp->d_un.d_val;
1417 break;
1418
1419 case DT_VERDEF:
1420 obj->verdef = (const Elf_Verdef *)(obj->relocbase +
1421 dynp->d_un.d_val);
1422 break;
1423
1424 case DT_VERDEFNUM:
1425 obj->verdefnum = dynp->d_un.d_val;
1426 break;
1427
1428 case DT_VERSYM:
1429 obj->versyms = (const Elf_Versym *)(obj->relocbase +
1430 dynp->d_un.d_val);
1431 break;
1432
1433 case DT_HASH: {
1434 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1435 dynp->d_un.d_ptr);
1436 obj->nbuckets = hashtab[0];
1437 obj->nchains = hashtab[1];
1438 obj->buckets = hashtab + 2;
1439 obj->chains = obj->buckets + obj->nbuckets;
1440 obj->valid_hash_sysv = obj->nbuckets > 0 &&
1441 obj->nchains > 0 && obj->buckets != NULL;
1442 } break;
1443
1444 case DT_GNU_HASH: {
1445 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1446 dynp->d_un.d_ptr);
1447 obj->nbuckets_gnu = hashtab[0];
1448 obj->symndx_gnu = hashtab[1];
1449 nmaskwords = hashtab[2];
1450 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
1451 obj->maskwords_bm_gnu = nmaskwords - 1;
1452 obj->shift2_gnu = hashtab[3];
1453 obj->bloom_gnu = (const Elf_Addr *)(hashtab + 4);
1454 obj->buckets_gnu = hashtab + 4 + bloom_size32;
1455 obj->chain_zero_gnu = obj->buckets_gnu +
1456 obj->nbuckets_gnu - obj->symndx_gnu;
1457 /* Number of bitmask words is required to be power of 2
1458 */
1459 obj->valid_hash_gnu = powerof2(nmaskwords) &&
1460 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL;
1461 } break;
1462
1463 case DT_NEEDED:
1464 if (!obj->rtld) {
1465 Needed_Entry *nep = NEW(Needed_Entry);
1466 nep->name = dynp->d_un.d_val;
1467 nep->obj = NULL;
1468 nep->next = NULL;
1469
1470 *needed_tail = nep;
1471 needed_tail = &nep->next;
1472 }
1473 break;
1474
1475 case DT_FILTER:
1476 if (!obj->rtld) {
1477 Needed_Entry *nep = NEW(Needed_Entry);
1478 nep->name = dynp->d_un.d_val;
1479 nep->obj = NULL;
1480 nep->next = NULL;
1481
1482 *needed_filtees_tail = nep;
1483 needed_filtees_tail = &nep->next;
1484
1485 if (obj->linkmap.l_refname == NULL)
1486 obj->linkmap.l_refname =
1487 (char *)dynp->d_un.d_val;
1488 }
1489 break;
1490
1491 case DT_AUXILIARY:
1492 if (!obj->rtld) {
1493 Needed_Entry *nep = NEW(Needed_Entry);
1494 nep->name = dynp->d_un.d_val;
1495 nep->obj = NULL;
1496 nep->next = NULL;
1497
1498 *needed_aux_filtees_tail = nep;
1499 needed_aux_filtees_tail = &nep->next;
1500 }
1501 break;
1502
1503 case DT_PLTGOT:
1504 obj->pltgot = (Elf_Addr *)(obj->relocbase +
1505 dynp->d_un.d_ptr);
1506 break;
1507
1508 case DT_TEXTREL:
1509 obj->textrel = true;
1510 break;
1511
1512 case DT_SYMBOLIC:
1513 obj->symbolic = true;
1514 break;
1515
1516 case DT_RPATH:
1517 /*
1518 * We have to wait until later to process this, because
1519 * we might not have gotten the address of the string
1520 * table yet.
1521 */
1522 *dyn_rpath = dynp;
1523 break;
1524
1525 case DT_SONAME:
1526 *dyn_soname = dynp;
1527 break;
1528
1529 case DT_RUNPATH:
1530 *dyn_runpath = dynp;
1531 break;
1532
1533 case DT_INIT:
1534 obj->init = (uintptr_t)(obj->relocbase +
1535 dynp->d_un.d_ptr);
1536 break;
1537
1538 case DT_PREINIT_ARRAY:
1539 obj->preinit_array = (uintptr_t *)(obj->relocbase +
1540 dynp->d_un.d_ptr);
1541 break;
1542
1543 case DT_PREINIT_ARRAYSZ:
1544 obj->preinit_array_num = dynp->d_un.d_val /
1545 sizeof(uintptr_t);
1546 break;
1547
1548 case DT_INIT_ARRAY:
1549 obj->init_array = (uintptr_t *)(obj->relocbase +
1550 dynp->d_un.d_ptr);
1551 break;
1552
1553 case DT_INIT_ARRAYSZ:
1554 obj->init_array_num = dynp->d_un.d_val /
1555 sizeof(uintptr_t);
1556 break;
1557
1558 case DT_FINI:
1559 obj->fini = (uintptr_t)(obj->relocbase +
1560 dynp->d_un.d_ptr);
1561 break;
1562
1563 case DT_FINI_ARRAY:
1564 obj->fini_array = (uintptr_t *)(obj->relocbase +
1565 dynp->d_un.d_ptr);
1566 break;
1567
1568 case DT_FINI_ARRAYSZ:
1569 obj->fini_array_num = dynp->d_un.d_val /
1570 sizeof(uintptr_t);
1571 break;
1572
1573 case DT_DEBUG:
1574 if (!early)
1575 dbg("Filling in DT_DEBUG entry");
1576 (__DECONST(Elf_Dyn *, dynp))->d_un.d_ptr =
1577 (Elf_Addr)&r_debug;
1578 break;
1579
1580 case DT_FLAGS:
1581 if (dynp->d_un.d_val & DF_ORIGIN)
1582 obj->z_origin = true;
1583 if (dynp->d_un.d_val & DF_SYMBOLIC)
1584 obj->symbolic = true;
1585 if (dynp->d_un.d_val & DF_TEXTREL)
1586 obj->textrel = true;
1587 if (dynp->d_un.d_val & DF_BIND_NOW)
1588 obj->bind_now = true;
1589 if (dynp->d_un.d_val & DF_STATIC_TLS)
1590 obj->static_tls = true;
1591 break;
1592
1593 case DT_FLAGS_1:
1594 if (dynp->d_un.d_val & DF_1_NOOPEN)
1595 obj->z_noopen = true;
1596 if (dynp->d_un.d_val & DF_1_ORIGIN)
1597 obj->z_origin = true;
1598 if (dynp->d_un.d_val & DF_1_GLOBAL)
1599 obj->z_global = true;
1600 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1601 obj->bind_now = true;
1602 if (dynp->d_un.d_val & DF_1_NODELETE)
1603 obj->z_nodelete = true;
1604 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1605 obj->z_loadfltr = true;
1606 if (dynp->d_un.d_val & DF_1_INTERPOSE)
1607 obj->z_interpose = true;
1608 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1609 obj->z_nodeflib = true;
1610 if (dynp->d_un.d_val & DF_1_PIE)
1611 obj->z_pie = true;
1612 if (dynp->d_un.d_val & DF_1_INITFIRST)
1613 obj->z_initfirst = true;
1614 break;
1615
1616 default:
1617 if (arch_digest_dynamic(obj, dynp))
1618 break;
1619
1620 if (!early) {
1621 dbg("Ignoring d_tag %ld = %#lx",
1622 (long)dynp->d_tag, (long)dynp->d_tag);
1623 }
1624 break;
1625 }
1626 }
1627
1628 obj->traced = false;
1629
1630 if (plttype == DT_RELA) {
1631 obj->pltrela = (const Elf_Rela *)obj->pltrel;
1632 obj->pltrel = NULL;
1633 obj->pltrelasize = obj->pltrelsize;
1634 obj->pltrelsize = 0;
1635 }
1636
1637 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1638 if (obj->valid_hash_sysv)
1639 obj->dynsymcount = obj->nchains;
1640 else if (obj->valid_hash_gnu) {
1641 obj->dynsymcount = 0;
1642 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1643 if (obj->buckets_gnu[bkt] == 0)
1644 continue;
1645 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1646 do
1647 obj->dynsymcount++;
1648 while ((*hashval++ & 1u) == 0);
1649 }
1650 obj->dynsymcount += obj->symndx_gnu;
1651 }
1652
1653 if (obj->linkmap.l_refname != NULL)
1654 obj->linkmap.l_refname = obj->strtab +
1655 (unsigned long)obj->linkmap.l_refname;
1656 }
1657
1658 static bool
obj_resolve_origin(Obj_Entry * obj)1659 obj_resolve_origin(Obj_Entry *obj)
1660 {
1661 if (obj->origin_path != NULL)
1662 return (true);
1663 obj->origin_path = xmalloc(PATH_MAX);
1664 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1);
1665 }
1666
1667 static bool
digest_dynamic2(Obj_Entry * obj,const Elf_Dyn * dyn_rpath,const Elf_Dyn * dyn_soname,const Elf_Dyn * dyn_runpath)1668 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1669 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1670 {
1671 if (obj->z_origin && !obj_resolve_origin(obj))
1672 return (false);
1673
1674 if (dyn_runpath != NULL) {
1675 obj->runpath = (const char *)obj->strtab +
1676 dyn_runpath->d_un.d_val;
1677 obj->runpath = origin_subst(obj, obj->runpath);
1678 } else if (dyn_rpath != NULL) {
1679 obj->rpath = (const char *)obj->strtab + dyn_rpath->d_un.d_val;
1680 obj->rpath = origin_subst(obj, obj->rpath);
1681 }
1682 if (dyn_soname != NULL)
1683 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1684 return (true);
1685 }
1686
1687 static bool
digest_dynamic(Obj_Entry * obj,int early)1688 digest_dynamic(Obj_Entry *obj, int early)
1689 {
1690 const Elf_Dyn *dyn_rpath;
1691 const Elf_Dyn *dyn_soname;
1692 const Elf_Dyn *dyn_runpath;
1693
1694 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1695 return (digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath));
1696 }
1697
1698 /*
1699 * Process a shared object's program header. This is used only for the
1700 * main program, when the kernel has already loaded the main program
1701 * into memory before calling the dynamic linker. It creates and
1702 * returns an Obj_Entry structure.
1703 */
1704 static Obj_Entry *
digest_phdr(const Elf_Phdr * phdr,int phnum,caddr_t entry,const char * path)1705 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1706 {
1707 Obj_Entry *obj;
1708 const Elf_Phdr *phlimit = phdr + phnum;
1709 const Elf_Phdr *ph;
1710 Elf_Addr note_start, note_end;
1711 int nsegs = 0;
1712
1713 obj = obj_new();
1714 for (ph = phdr; ph < phlimit; ph++) {
1715 if (ph->p_type != PT_PHDR)
1716 continue;
1717
1718 obj->phdr = phdr;
1719 obj->phnum = ph->p_memsz / sizeof(*ph);
1720 obj->relocbase = __DECONST(char *, phdr) - ph->p_vaddr;
1721 break;
1722 }
1723
1724 obj->stack_flags = PF_X | PF_R | PF_W;
1725
1726 for (ph = phdr; ph < phlimit; ph++) {
1727 switch (ph->p_type) {
1728 case PT_INTERP:
1729 obj->interp = (const char *)(ph->p_vaddr +
1730 obj->relocbase);
1731 break;
1732
1733 case PT_LOAD:
1734 if (nsegs == 0) { /* First load segment */
1735 obj->vaddrbase = rtld_trunc_page(ph->p_vaddr);
1736 obj->mapbase = obj->vaddrbase + obj->relocbase;
1737 } else { /* Last load segment */
1738 obj->mapsize = rtld_round_page(
1739 ph->p_vaddr + ph->p_memsz) -
1740 obj->vaddrbase;
1741 }
1742 nsegs++;
1743 break;
1744
1745 case PT_DYNAMIC:
1746 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr +
1747 obj->relocbase);
1748 break;
1749
1750 case PT_TLS:
1751 if (ph->p_memsz < ph->p_filesz) {
1752 _rtld_error("%s: invalid PT_TLS segment",
1753 path);
1754 return (NULL);
1755 }
1756
1757 obj->tlsindex = 1;
1758 obj->tlssize = ph->p_memsz;
1759 obj->tlsalign = ph->p_align;
1760 obj->tlsinitsize = ph->p_filesz;
1761 obj->tlsinit = (void *)(ph->p_vaddr + obj->relocbase);
1762 obj->tlspoffset = ph->p_offset;
1763 break;
1764
1765 case PT_GNU_STACK:
1766 obj->stack_flags = ph->p_flags;
1767 break;
1768
1769 case PT_NOTE:
1770 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1771 note_end = note_start + ph->p_filesz;
1772 digest_notes(obj, note_start, note_end);
1773 break;
1774 }
1775 }
1776 if (nsegs < 1) {
1777 _rtld_error("%s: too few PT_LOAD segments", path);
1778 return (NULL);
1779 }
1780
1781 obj->entry = entry;
1782 return (obj);
1783 }
1784
1785 void
digest_notes(Obj_Entry * obj,Elf_Addr note_start,Elf_Addr note_end)1786 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1787 {
1788 const Elf_Note *note, *next_note;
1789 const char *note_name;
1790 uintptr_t p;
1791
1792 for (note = (const Elf_Note *)note_start;; note = next_note) {
1793 if ((Elf_Addr)note + sizeof(Elf_Note) > note_end)
1794 break;
1795 next_note = (const Elf_Note *)((const char *)(note + 1) +
1796 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1797 roundup2(note->n_descsz, sizeof(Elf32_Addr)));
1798 if ((Elf_Addr)next_note > note_end)
1799 break;
1800
1801 if (arch_digest_note(obj, note))
1802 continue;
1803
1804 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1805 note->n_descsz != sizeof(int32_t))
1806 continue;
1807 if (note->n_type != NT_FREEBSD_ABI_TAG &&
1808 note->n_type != NT_FREEBSD_FEATURE_CTL &&
1809 note->n_type != NT_FREEBSD_NOINIT_TAG)
1810 continue;
1811 note_name = (const char *)(note + 1);
1812 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1813 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1814 continue;
1815 switch (note->n_type) {
1816 case NT_FREEBSD_ABI_TAG:
1817 /* FreeBSD osrel note */
1818 p = (uintptr_t)(note + 1);
1819 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1820 obj->osrel = *(const int32_t *)(p);
1821 dbg("note osrel %d", obj->osrel);
1822 break;
1823 case NT_FREEBSD_FEATURE_CTL:
1824 /* FreeBSD ABI feature control note */
1825 p = (uintptr_t)(note + 1);
1826 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1827 obj->fctl0 = *(const uint32_t *)(p);
1828 dbg("note fctl0 %#x", obj->fctl0);
1829 break;
1830 case NT_FREEBSD_NOINIT_TAG:
1831 /* FreeBSD 'crt does not call init' note */
1832 obj->crt_no_init = true;
1833 dbg("note crt_no_init");
1834 break;
1835 }
1836 }
1837 }
1838
1839 static Obj_Entry *
dlcheck(void * handle)1840 dlcheck(void *handle)
1841 {
1842 Obj_Entry *obj;
1843
1844 TAILQ_FOREACH(obj, &obj_list, next) {
1845 if (obj == (Obj_Entry *)handle)
1846 break;
1847 }
1848
1849 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1850 _rtld_error("Invalid shared object handle %p", handle);
1851 return (NULL);
1852 }
1853 return (obj);
1854 }
1855
1856 /*
1857 * If the given object is already in the donelist, return true. Otherwise
1858 * add the object to the list and return false.
1859 */
1860 static bool
donelist_check(DoneList * dlp,const Obj_Entry * obj)1861 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1862 {
1863 unsigned int i;
1864
1865 for (i = 0; i < dlp->num_used; i++)
1866 if (dlp->objs[i] == obj)
1867 return (true);
1868 /*
1869 * Our donelist allocation should always be sufficient. But if
1870 * our threads locking isn't working properly, more shared objects
1871 * could have been loaded since we allocated the list. That should
1872 * never happen, but we'll handle it properly just in case it does.
1873 */
1874 if (dlp->num_used < dlp->num_alloc)
1875 dlp->objs[dlp->num_used++] = obj;
1876 return (false);
1877 }
1878
1879 /*
1880 * SysV hash function for symbol table lookup. It is a slightly optimized
1881 * version of the hash specified by the System V ABI.
1882 */
1883 Elf32_Word
elf_hash(const char * name)1884 elf_hash(const char *name)
1885 {
1886 const unsigned char *p = (const unsigned char *)name;
1887 Elf32_Word h = 0;
1888
1889 while (*p != '\0') {
1890 h = (h << 4) + *p++;
1891 h ^= (h >> 24) & 0xf0;
1892 }
1893 return (h & 0x0fffffff);
1894 }
1895
1896 /*
1897 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1898 * unsigned in case it's implemented with a wider type.
1899 */
1900 static uint32_t
gnu_hash(const char * s)1901 gnu_hash(const char *s)
1902 {
1903 uint32_t h;
1904 unsigned char c;
1905
1906 h = 5381;
1907 for (c = *s; c != '\0'; c = *++s)
1908 h = h * 33 + c;
1909 return (h & 0xffffffff);
1910 }
1911
1912 /*
1913 * Find the library with the given name, and return its full pathname.
1914 * The returned string is dynamically allocated. Generates an error
1915 * message and returns NULL if the library cannot be found.
1916 *
1917 * If the second argument is non-NULL, then it refers to an already-
1918 * loaded shared object, whose library search path will be searched.
1919 *
1920 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its
1921 * descriptor (which is close-on-exec) will be passed out via the third
1922 * argument.
1923 *
1924 * The search order is:
1925 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1926 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1927 * LD_LIBRARY_PATH
1928 * DT_RUNPATH in the referencing file
1929 * ldconfig hints (if -z nodefaultlib, filter out default library directories
1930 * from list)
1931 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1932 *
1933 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1934 */
1935 static char *
find_library(const char * xname,const Obj_Entry * refobj,int * fdp)1936 find_library(const char *xname, const Obj_Entry *refobj, int *fdp)
1937 {
1938 char *pathname, *refobj_path;
1939 const char *name;
1940 bool nodeflib, objgiven;
1941
1942 objgiven = refobj != NULL;
1943
1944 if (libmap_disable || !objgiven ||
1945 (name = lm_find(refobj->path, xname)) == NULL)
1946 name = xname;
1947
1948 if (strchr(name, '/') != NULL) { /* Hard coded pathname */
1949 if (name[0] != '/' && !trust) {
1950 _rtld_error(
1951 "Absolute pathname required for shared object \"%s\"",
1952 name);
1953 return (NULL);
1954 }
1955 return (origin_subst(__DECONST(Obj_Entry *, refobj),
1956 __DECONST(char *, name)));
1957 }
1958
1959 dbg(" Searching for \"%s\"", name);
1960 refobj_path = objgiven ? refobj->path : NULL;
1961
1962 /*
1963 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall
1964 * back to pre-conforming behaviour if user requested so with
1965 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z
1966 * nodeflib.
1967 */
1968 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) {
1969 pathname = search_library_path(name, ld_library_path,
1970 refobj_path, fdp);
1971 if (pathname != NULL)
1972 return (pathname);
1973 if (refobj != NULL) {
1974 pathname = search_library_path(name, refobj->rpath,
1975 refobj_path, fdp);
1976 if (pathname != NULL)
1977 return (pathname);
1978 }
1979 pathname = search_library_pathfds(name, ld_library_dirs, fdp);
1980 if (pathname != NULL)
1981 return (pathname);
1982 pathname = search_library_path(name, gethints(false),
1983 refobj_path, fdp);
1984 if (pathname != NULL)
1985 return (pathname);
1986 pathname = search_library_path(name, ld_standard_library_path,
1987 refobj_path, fdp);
1988 if (pathname != NULL)
1989 return (pathname);
1990 } else {
1991 nodeflib = objgiven ? refobj->z_nodeflib : false;
1992 if (objgiven) {
1993 pathname = search_library_path(name, refobj->rpath,
1994 refobj->path, fdp);
1995 if (pathname != NULL)
1996 return (pathname);
1997 }
1998 if (objgiven && refobj->runpath == NULL && refobj != obj_main) {
1999 pathname = search_library_path(name, obj_main->rpath,
2000 refobj_path, fdp);
2001 if (pathname != NULL)
2002 return (pathname);
2003 }
2004 pathname = search_library_path(name, ld_library_path,
2005 refobj_path, fdp);
2006 if (pathname != NULL)
2007 return (pathname);
2008 if (objgiven) {
2009 pathname = search_library_path(name, refobj->runpath,
2010 refobj_path, fdp);
2011 if (pathname != NULL)
2012 return (pathname);
2013 }
2014 pathname = search_library_pathfds(name, ld_library_dirs, fdp);
2015 if (pathname != NULL)
2016 return (pathname);
2017 pathname = search_library_path(name, gethints(nodeflib),
2018 refobj_path, fdp);
2019 if (pathname != NULL)
2020 return (pathname);
2021 if (objgiven && !nodeflib) {
2022 pathname = search_library_path(name,
2023 ld_standard_library_path, refobj_path, fdp);
2024 if (pathname != NULL)
2025 return (pathname);
2026 }
2027 }
2028
2029 if (objgiven && refobj->path != NULL) {
2030 _rtld_error(
2031 "Shared object \"%s\" not found, required by \"%s\"",
2032 name, basename(refobj->path));
2033 } else {
2034 _rtld_error("Shared object \"%s\" not found", name);
2035 }
2036 return (NULL);
2037 }
2038
2039 /*
2040 * Given a symbol number in a referencing object, find the corresponding
2041 * definition of the symbol. Returns a pointer to the symbol, or NULL if
2042 * no definition was found. Returns a pointer to the Obj_Entry of the
2043 * defining object via the reference parameter DEFOBJ_OUT.
2044 */
2045 const Elf_Sym *
find_symdef(unsigned long symnum,const Obj_Entry * refobj,const Obj_Entry ** defobj_out,int flags,SymCache * cache,RtldLockState * lockstate)2046 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
2047 const Obj_Entry **defobj_out, int flags, SymCache *cache,
2048 RtldLockState *lockstate)
2049 {
2050 const Elf_Sym *ref;
2051 const Elf_Sym *def;
2052 const Obj_Entry *defobj;
2053 const Ver_Entry *ve;
2054 SymLook req;
2055 const char *name;
2056 int res;
2057
2058 /*
2059 * If we have already found this symbol, get the information from
2060 * the cache.
2061 */
2062 if (symnum >= refobj->dynsymcount)
2063 return (NULL); /* Bad object */
2064 if (cache != NULL && cache[symnum].sym != NULL) {
2065 *defobj_out = cache[symnum].obj;
2066 return (cache[symnum].sym);
2067 }
2068
2069 ref = refobj->symtab + symnum;
2070 name = refobj->strtab + ref->st_name;
2071 def = NULL;
2072 defobj = NULL;
2073 ve = NULL;
2074
2075 /*
2076 * We don't have to do a full scale lookup if the symbol is local.
2077 * We know it will bind to the instance in this load module; to
2078 * which we already have a pointer (ie ref). By not doing a lookup,
2079 * we not only improve performance, but it also avoids unresolvable
2080 * symbols when local symbols are not in the hash table. This has
2081 * been seen with the ia64 toolchain.
2082 */
2083 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
2084 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
2085 _rtld_error("%s: Bogus symbol table entry %lu",
2086 refobj->path, symnum);
2087 }
2088 symlook_init(&req, name);
2089 req.flags = flags;
2090 ve = req.ventry = fetch_ventry(refobj, symnum);
2091 req.lockstate = lockstate;
2092 res = symlook_default(&req, refobj);
2093 if (res == 0) {
2094 def = req.sym_out;
2095 defobj = req.defobj_out;
2096 }
2097 } else {
2098 def = ref;
2099 defobj = refobj;
2100 }
2101
2102 /*
2103 * If we found no definition and the reference is weak, treat the
2104 * symbol as having the value zero.
2105 */
2106 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
2107 def = &sym_zero;
2108 defobj = obj_main;
2109 }
2110
2111 if (def != NULL) {
2112 *defobj_out = defobj;
2113 /*
2114 * Record the information in the cache to avoid subsequent
2115 * lookups.
2116 */
2117 if (cache != NULL) {
2118 cache[symnum].sym = def;
2119 cache[symnum].obj = defobj;
2120 }
2121 } else {
2122 if (refobj != &obj_rtld)
2123 _rtld_error("%s: Undefined symbol \"%s%s%s\"",
2124 refobj->path, name, ve != NULL ? "@" : "",
2125 ve != NULL ? ve->name : "");
2126 }
2127 return (def);
2128 }
2129
2130 /* Convert between native byte order and forced little resp. big endian. */
2131 #define COND_SWAP(n) (is_le ? le32toh(n) : be32toh(n))
2132
2133 /*
2134 * Return the search path from the ldconfig hints file, reading it if
2135 * necessary. If nostdlib is true, then the default search paths are
2136 * not added to result.
2137 *
2138 * Returns NULL if there are problems with the hints file,
2139 * or if the search path there is empty.
2140 */
2141 static const char *
gethints(bool nostdlib)2142 gethints(bool nostdlib)
2143 {
2144 static char *filtered_path;
2145 static const char *hints;
2146 static struct elfhints_hdr hdr;
2147 struct fill_search_info_args sargs, hargs;
2148 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
2149 struct dl_serpath *SLPpath, *hintpath;
2150 char *p;
2151 struct stat hint_stat;
2152 unsigned int SLPndx, hintndx, fndx, fcount;
2153 int fd;
2154 size_t flen;
2155 uint32_t dl;
2156 uint32_t magic; /* Magic number */
2157 uint32_t version; /* File version (1) */
2158 uint32_t strtab; /* Offset of string table in file */
2159 uint32_t dirlist; /* Offset of directory list in string table */
2160 uint32_t dirlistlen; /* strlen(dirlist) */
2161 bool is_le; /* Does the hints file use little endian */
2162 bool skip;
2163
2164 /* First call, read the hints file */
2165 if (hints == NULL) {
2166 /* Keep from trying again in case the hints file is bad. */
2167 hints = "";
2168
2169 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) ==
2170 -1) {
2171 dbg("failed to open hints file \"%s\"",
2172 ld_elf_hints_path);
2173 return (NULL);
2174 }
2175
2176 /*
2177 * Check of hdr.dirlistlen value against type limit
2178 * intends to pacify static analyzers. Further
2179 * paranoia leads to checks that dirlist is fully
2180 * contained in the file range.
2181 */
2182 if (read(fd, &hdr, sizeof hdr) != sizeof hdr) {
2183 dbg("failed to read %lu bytes from hints file \"%s\"",
2184 (u_long)sizeof hdr, ld_elf_hints_path);
2185 cleanup1:
2186 close(fd);
2187 hdr.dirlistlen = 0;
2188 return (NULL);
2189 }
2190 dbg("host byte-order: %s-endian",
2191 le32toh(1) == 1 ? "little" : "big");
2192 dbg("hints file byte-order: %s-endian",
2193 hdr.magic == htole32(ELFHINTS_MAGIC) ? "little" : "big");
2194 is_le = /*htole32(1) == 1 || */ hdr.magic ==
2195 htole32(ELFHINTS_MAGIC);
2196 magic = COND_SWAP(hdr.magic);
2197 version = COND_SWAP(hdr.version);
2198 strtab = COND_SWAP(hdr.strtab);
2199 dirlist = COND_SWAP(hdr.dirlist);
2200 dirlistlen = COND_SWAP(hdr.dirlistlen);
2201 if (magic != ELFHINTS_MAGIC) {
2202 dbg("invalid magic number %#08x (expected: %#08x)",
2203 magic, ELFHINTS_MAGIC);
2204 goto cleanup1;
2205 }
2206 if (version != 1) {
2207 dbg("hints file version %d (expected: 1)", version);
2208 goto cleanup1;
2209 }
2210 if (dirlistlen > UINT_MAX / 2) {
2211 dbg("directory list is to long: %d > %d", dirlistlen,
2212 UINT_MAX / 2);
2213 goto cleanup1;
2214 }
2215 if (fstat(fd, &hint_stat) == -1) {
2216 dbg("failed to find length of hints file \"%s\"",
2217 ld_elf_hints_path);
2218 goto cleanup1;
2219 }
2220 dl = strtab;
2221 if (dl + dirlist < dl) {
2222 dbg("invalid string table position %d", dl);
2223 goto cleanup1;
2224 }
2225 dl += dirlist;
2226 if (dl + dirlistlen < dl) {
2227 dbg("invalid directory list offset %d", dirlist);
2228 goto cleanup1;
2229 }
2230 dl += dirlistlen;
2231 if (dl > hint_stat.st_size) {
2232 dbg("hints file \"%s\" is truncated (%d vs. %jd bytes)",
2233 ld_elf_hints_path, dl,
2234 (uintmax_t)hint_stat.st_size);
2235 goto cleanup1;
2236 }
2237 p = xmalloc(dirlistlen + 1);
2238 if (pread(fd, p, dirlistlen + 1, strtab + dirlist) !=
2239 (ssize_t)dirlistlen + 1 || p[dirlistlen] != '\0') {
2240 free(p);
2241 dbg(
2242 "failed to read %d bytes starting at %d from hints file \"%s\"",
2243 dirlistlen + 1, strtab + dirlist,
2244 ld_elf_hints_path);
2245 goto cleanup1;
2246 }
2247 hints = p;
2248 close(fd);
2249 }
2250
2251 /*
2252 * If caller agreed to receive list which includes the default
2253 * paths, we are done. Otherwise, if we still did not
2254 * calculated filtered result, do it now.
2255 */
2256 if (!nostdlib)
2257 return (hints[0] != '\0' ? hints : NULL);
2258 if (filtered_path != NULL)
2259 goto filt_ret;
2260
2261 /*
2262 * Obtain the list of all configured search paths, and the
2263 * list of the default paths.
2264 *
2265 * First estimate the size of the results.
2266 */
2267 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
2268 smeta.dls_cnt = 0;
2269 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
2270 hmeta.dls_cnt = 0;
2271
2272 sargs.request = RTLD_DI_SERINFOSIZE;
2273 sargs.serinfo = &smeta;
2274 hargs.request = RTLD_DI_SERINFOSIZE;
2275 hargs.serinfo = &hmeta;
2276
2277 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
2278 &sargs);
2279 path_enumerate(hints, fill_search_info, NULL, &hargs);
2280
2281 SLPinfo = xmalloc(smeta.dls_size);
2282 hintinfo = xmalloc(hmeta.dls_size);
2283
2284 /*
2285 * Next fetch both sets of paths.
2286 */
2287 sargs.request = RTLD_DI_SERINFO;
2288 sargs.serinfo = SLPinfo;
2289 sargs.serpath = &SLPinfo->dls_serpath[0];
2290 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
2291
2292 hargs.request = RTLD_DI_SERINFO;
2293 hargs.serinfo = hintinfo;
2294 hargs.serpath = &hintinfo->dls_serpath[0];
2295 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
2296
2297 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
2298 &sargs);
2299 path_enumerate(hints, fill_search_info, NULL, &hargs);
2300
2301 /*
2302 * Now calculate the difference between two sets, by excluding
2303 * standard paths from the full set.
2304 */
2305 fndx = 0;
2306 fcount = 0;
2307 filtered_path = xmalloc(dirlistlen + 1);
2308 hintpath = &hintinfo->dls_serpath[0];
2309 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
2310 skip = false;
2311 SLPpath = &SLPinfo->dls_serpath[0];
2312 /*
2313 * Check each standard path against current.
2314 */
2315 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
2316 /* matched, skip the path */
2317 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
2318 skip = true;
2319 break;
2320 }
2321 }
2322 if (skip)
2323 continue;
2324 /*
2325 * Not matched against any standard path, add the path
2326 * to result. Separate consequtive paths with ':'.
2327 */
2328 if (fcount > 0) {
2329 filtered_path[fndx] = ':';
2330 fndx++;
2331 }
2332 fcount++;
2333 flen = strlen(hintpath->dls_name);
2334 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
2335 fndx += flen;
2336 }
2337 filtered_path[fndx] = '\0';
2338
2339 free(SLPinfo);
2340 free(hintinfo);
2341
2342 filt_ret:
2343 return (filtered_path[0] != '\0' ? filtered_path : NULL);
2344 }
2345
2346 static void
init_dag(Obj_Entry * root)2347 init_dag(Obj_Entry *root)
2348 {
2349 const Needed_Entry *needed;
2350 const Objlist_Entry *elm;
2351 DoneList donelist;
2352
2353 if (root->dag_inited)
2354 return;
2355 donelist_init(&donelist, NULL);
2356
2357 /* Root object belongs to own DAG. */
2358 objlist_push_tail(&root->dldags, root);
2359 objlist_push_tail(&root->dagmembers, root);
2360 donelist_check(&donelist, root);
2361
2362 /*
2363 * Add dependencies of root object to DAG in breadth order
2364 * by exploiting the fact that each new object get added
2365 * to the tail of the dagmembers list.
2366 */
2367 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2368 for (needed = elm->obj->needed; needed != NULL;
2369 needed = needed->next) {
2370 if (needed->obj == NULL ||
2371 donelist_check(&donelist, needed->obj))
2372 continue;
2373 objlist_push_tail(&needed->obj->dldags, root);
2374 objlist_push_tail(&root->dagmembers, needed->obj);
2375 }
2376 }
2377 root->dag_inited = true;
2378 donelist_free(&donelist);
2379 }
2380
2381 static void
init_marker(Obj_Entry * marker)2382 init_marker(Obj_Entry *marker)
2383 {
2384 bzero(marker, sizeof(*marker));
2385 marker->marker = true;
2386 }
2387
2388 Obj_Entry *
globallist_curr(const Obj_Entry * obj)2389 globallist_curr(const Obj_Entry *obj)
2390 {
2391 for (;;) {
2392 if (obj == NULL)
2393 return (NULL);
2394 if (!obj->marker)
2395 return (__DECONST(Obj_Entry *, obj));
2396 obj = TAILQ_PREV(obj, obj_entry_q, next);
2397 }
2398 }
2399
2400 Obj_Entry *
globallist_next(const Obj_Entry * obj)2401 globallist_next(const Obj_Entry *obj)
2402 {
2403 for (;;) {
2404 obj = TAILQ_NEXT(obj, next);
2405 if (obj == NULL)
2406 return (NULL);
2407 if (!obj->marker)
2408 return (__DECONST(Obj_Entry *, obj));
2409 }
2410 }
2411
2412 /* Prevent the object from being unmapped while the bind lock is dropped. */
2413 static void
hold_object(Obj_Entry * obj)2414 hold_object(Obj_Entry *obj)
2415 {
2416 obj->holdcount++;
2417 }
2418
2419 static void
unhold_object(Obj_Entry * obj)2420 unhold_object(Obj_Entry *obj)
2421 {
2422 assert(obj->holdcount > 0);
2423 if (--obj->holdcount == 0 && obj->unholdfree)
2424 release_object(obj);
2425 }
2426
2427 static void
process_z(Obj_Entry * root)2428 process_z(Obj_Entry *root)
2429 {
2430 const Objlist_Entry *elm;
2431 Obj_Entry *obj;
2432
2433 /*
2434 * Walk over object DAG and process every dependent object
2435 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need
2436 * to grow their own DAG.
2437 *
2438 * For DF_1_GLOBAL, DAG is required for symbol lookups in
2439 * symlook_global() to work.
2440 *
2441 * For DF_1_NODELETE, the DAG should have its reference upped.
2442 */
2443 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2444 obj = elm->obj;
2445 if (obj == NULL)
2446 continue;
2447 if (obj->z_nodelete && !obj->ref_nodel) {
2448 dbg("obj %s -z nodelete", obj->path);
2449 init_dag(obj);
2450 ref_dag(obj);
2451 obj->ref_nodel = true;
2452 }
2453 if (obj->z_global && objlist_find(&list_global, obj) == NULL) {
2454 dbg("obj %s -z global", obj->path);
2455 objlist_push_tail(&list_global, obj);
2456 init_dag(obj);
2457 }
2458 }
2459 }
2460
2461 static void
parse_rtld_phdr(Obj_Entry * obj)2462 parse_rtld_phdr(Obj_Entry *obj)
2463 {
2464 const Elf_Phdr *ph;
2465 Elf_Addr note_start, note_end;
2466 bool first_seg;
2467
2468 first_seg = true;
2469 obj->stack_flags = PF_X | PF_R | PF_W;
2470 for (ph = obj->phdr; ph < obj->phdr + obj->phnum; ph++) {
2471 switch (ph->p_type) {
2472 case PT_LOAD:
2473 if (first_seg) {
2474 obj->vaddrbase = rtld_trunc_page(ph->p_vaddr);
2475 first_seg = false;
2476 }
2477 obj->mapsize = rtld_round_page(ph->p_vaddr +
2478 ph->p_memsz) - obj->vaddrbase;
2479 break;
2480 case PT_GNU_STACK:
2481 obj->stack_flags = ph->p_flags;
2482 break;
2483 case PT_NOTE:
2484 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
2485 note_end = note_start + ph->p_filesz;
2486 digest_notes(obj, note_start, note_end);
2487 break;
2488 }
2489 }
2490 }
2491
2492 /*
2493 * Initialize the dynamic linker. The argument is the address at which
2494 * the dynamic linker has been mapped into memory. The primary task of
2495 * this function is to relocate the dynamic linker.
2496 */
2497 static void
init_rtld(caddr_t mapbase,Elf_Auxinfo ** aux_info)2498 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
2499 {
2500 Obj_Entry objtmp; /* Temporary rtld object */
2501 const Elf_Ehdr *ehdr;
2502 const Elf_Dyn *dyn_rpath;
2503 const Elf_Dyn *dyn_soname;
2504 const Elf_Dyn *dyn_runpath;
2505
2506 /*
2507 * Conjure up an Obj_Entry structure for the dynamic linker.
2508 *
2509 * The "path" member can't be initialized yet because string constants
2510 * cannot yet be accessed. Below we will set it correctly.
2511 */
2512 memset(&objtmp, 0, sizeof(objtmp));
2513 objtmp.path = NULL;
2514 objtmp.rtld = true;
2515 objtmp.mapbase = mapbase;
2516 objtmp.relocbase = mapbase;
2517
2518 objtmp.dynamic = rtld_dynamic(&objtmp);
2519 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
2520 assert(objtmp.needed == NULL);
2521 assert(!objtmp.textrel);
2522 /*
2523 * Temporarily put the dynamic linker entry into the object list, so
2524 * that symbols can be found.
2525 */
2526 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
2527
2528 ehdr = (Elf_Ehdr *)mapbase;
2529 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff);
2530 objtmp.phnum = ehdr->e_phnum;
2531
2532 /* Initialize the object list. */
2533 TAILQ_INIT(&obj_list);
2534
2535 /* Now that non-local variables can be accesses, copy out obj_rtld. */
2536 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
2537
2538 /* The page size is required by the dynamic memory allocator. */
2539 init_pagesizes(aux_info);
2540
2541 if (aux_info[AT_OSRELDATE] != NULL)
2542 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
2543
2544 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
2545
2546 /* Replace the path with a dynamically allocated copy. */
2547 obj_rtld.path = xstrdup(ld_path_rtld);
2548
2549 parse_rtld_phdr(&obj_rtld);
2550 if (obj_enforce_relro(&obj_rtld) == -1)
2551 rtld_die();
2552
2553 r_debug.r_version = R_DEBUG_VERSION;
2554 r_debug.r_brk = r_debug_state;
2555 r_debug.r_state = RT_CONSISTENT;
2556 r_debug.r_ldbase = obj_rtld.relocbase;
2557 }
2558
2559 /*
2560 * Retrieve the array of supported page sizes. The kernel provides the page
2561 * sizes in increasing order.
2562 */
2563 static void
init_pagesizes(Elf_Auxinfo ** aux_info)2564 init_pagesizes(Elf_Auxinfo **aux_info)
2565 {
2566 static size_t psa[MAXPAGESIZES];
2567 int mib[2];
2568 size_t len, size;
2569
2570 if (aux_info[AT_PAGESIZES] != NULL &&
2571 aux_info[AT_PAGESIZESLEN] != NULL) {
2572 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val;
2573 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr;
2574 } else {
2575 len = 2;
2576 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0)
2577 size = sizeof(psa);
2578 else {
2579 /* As a fallback, retrieve the base page size. */
2580 size = sizeof(psa[0]);
2581 if (aux_info[AT_PAGESZ] != NULL) {
2582 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val;
2583 goto psa_filled;
2584 } else {
2585 mib[0] = CTL_HW;
2586 mib[1] = HW_PAGESIZE;
2587 len = 2;
2588 }
2589 }
2590 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) {
2591 _rtld_error("sysctl for hw.pagesize(s) failed");
2592 rtld_die();
2593 }
2594 psa_filled:
2595 pagesizes = psa;
2596 }
2597 npagesizes = size / sizeof(pagesizes[0]);
2598 /* Discard any invalid entries at the end of the array. */
2599 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0)
2600 npagesizes--;
2601
2602 page_size = pagesizes[0];
2603 }
2604
2605 /*
2606 * Add the init functions from a needed object list (and its recursive
2607 * needed objects) to "list". This is not used directly; it is a helper
2608 * function for initlist_add_objects(). The write lock must be held
2609 * when this function is called.
2610 */
2611 static void
initlist_add_neededs(Needed_Entry * needed,Objlist * list,Objlist * iflist)2612 initlist_add_neededs(Needed_Entry *needed, Objlist *list, Objlist *iflist)
2613 {
2614 /* Recursively process the successor needed objects. */
2615 if (needed->next != NULL)
2616 initlist_add_neededs(needed->next, list, iflist);
2617
2618 /* Process the current needed object. */
2619 if (needed->obj != NULL)
2620 initlist_add_objects(needed->obj, needed->obj, list, iflist);
2621 }
2622
2623 /*
2624 * Scan all of the DAGs rooted in the range of objects from "obj" to
2625 * "tail" and add their init functions to "list". This recurses over
2626 * the DAGs and ensure the proper init ordering such that each object's
2627 * needed libraries are initialized before the object itself. At the
2628 * same time, this function adds the objects to the global finalization
2629 * list "list_fini" in the opposite order. The write lock must be
2630 * held when this function is called.
2631 */
2632 static void
initlist_for_loaded_obj(Obj_Entry * obj,Obj_Entry * tail,Objlist * list)2633 initlist_for_loaded_obj(Obj_Entry *obj, Obj_Entry *tail, Objlist *list)
2634 {
2635 Objlist iflist; /* initfirst objs and their needed */
2636 Objlist_Entry *tmp;
2637
2638 objlist_init(&iflist);
2639 initlist_add_objects(obj, tail, list, &iflist);
2640
2641 STAILQ_FOREACH(tmp, &iflist, link) {
2642 Obj_Entry *tobj = tmp->obj;
2643
2644 if ((tobj->fini != 0 || tobj->fini_array != NULL) &&
2645 !tobj->on_fini_list) {
2646 objlist_push_tail(&list_fini, tobj);
2647 tobj->on_fini_list = true;
2648 }
2649 }
2650
2651 /*
2652 * This might result in the same object appearing more
2653 * than once on the init list. objlist_call_init()
2654 * uses obj->init_scanned to avoid dup calls.
2655 */
2656 STAILQ_REVERSE(&iflist, Struct_Objlist_Entry, link);
2657 STAILQ_FOREACH(tmp, &iflist, link)
2658 objlist_push_head(list, tmp->obj);
2659
2660 objlist_clear(&iflist);
2661 }
2662
2663 static void
initlist_add_objects(Obj_Entry * obj,Obj_Entry * tail,Objlist * list,Objlist * iflist)2664 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list,
2665 Objlist *iflist)
2666 {
2667 Obj_Entry *nobj;
2668
2669 if (obj->init_done)
2670 return;
2671
2672 if (obj->z_initfirst || list == NULL) {
2673 /*
2674 * Ignore obj->init_scanned. The object might indeed
2675 * already be on the init list, but due to being
2676 * needed by an initfirst object, we must put it at
2677 * the head of the init list. obj->init_done protects
2678 * against double-initialization.
2679 */
2680 if (obj->needed != NULL)
2681 initlist_add_neededs(obj->needed, NULL, iflist);
2682 if (obj->needed_filtees != NULL)
2683 initlist_add_neededs(obj->needed_filtees, NULL,
2684 iflist);
2685 if (obj->needed_aux_filtees != NULL)
2686 initlist_add_neededs(obj->needed_aux_filtees,
2687 NULL, iflist);
2688 objlist_push_tail(iflist, obj);
2689
2690 /* Recursively process the successor objects. */
2691 nobj = globallist_next(obj);
2692 if (nobj != NULL && obj != tail)
2693 initlist_add_objects(nobj, tail, list, iflist);
2694 } else {
2695 if (obj->init_scanned)
2696 return;
2697 obj->init_scanned = true;
2698
2699 /* Recursively process the successor objects. */
2700 nobj = globallist_next(obj);
2701 if (nobj != NULL && obj != tail)
2702 initlist_add_objects(nobj, tail, list, iflist);
2703
2704 /* Recursively process the needed objects. */
2705 if (obj->needed != NULL)
2706 initlist_add_neededs(obj->needed, list, iflist);
2707 if (obj->needed_filtees != NULL)
2708 initlist_add_neededs(obj->needed_filtees, list,
2709 iflist);
2710 if (obj->needed_aux_filtees != NULL)
2711 initlist_add_neededs(obj->needed_aux_filtees, list,
2712 iflist);
2713
2714 /* Add the object to the init list. */
2715 objlist_push_tail(list, obj);
2716
2717 /*
2718 * Add the object to the global fini list in the
2719 * reverse order.
2720 */
2721 if ((obj->fini != 0 || obj->fini_array != NULL) &&
2722 !obj->on_fini_list) {
2723 objlist_push_head(&list_fini, obj);
2724 obj->on_fini_list = true;
2725 }
2726 }
2727 }
2728
2729 static void
free_needed_filtees(Needed_Entry * n,RtldLockState * lockstate)2730 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate)
2731 {
2732 Needed_Entry *needed, *needed1;
2733
2734 for (needed = n; needed != NULL; needed = needed->next) {
2735 if (needed->obj != NULL) {
2736 dlclose_locked(needed->obj, lockstate);
2737 needed->obj = NULL;
2738 }
2739 }
2740 for (needed = n; needed != NULL; needed = needed1) {
2741 needed1 = needed->next;
2742 free(needed);
2743 }
2744 }
2745
2746 static void
unload_filtees(Obj_Entry * obj,RtldLockState * lockstate)2747 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate)
2748 {
2749 free_needed_filtees(obj->needed_filtees, lockstate);
2750 obj->needed_filtees = NULL;
2751 free_needed_filtees(obj->needed_aux_filtees, lockstate);
2752 obj->needed_aux_filtees = NULL;
2753 obj->filtees_loaded = false;
2754 }
2755
2756 static void
load_filtee1(Obj_Entry * obj,Needed_Entry * needed,int flags,RtldLockState * lockstate)2757 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
2758 RtldLockState *lockstate)
2759 {
2760 for (; needed != NULL; needed = needed->next) {
2761 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
2762 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW :
2763 RTLD_LAZY) | RTLD_LOCAL, lockstate);
2764 }
2765 }
2766
2767 static void
load_filtees(Obj_Entry * obj,int flags,RtldLockState * lockstate)2768 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
2769 {
2770 if (obj->filtees_loaded || obj->filtees_loading)
2771 return;
2772 lock_restart_for_upgrade(lockstate);
2773 obj->filtees_loading = true;
2774 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
2775 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
2776 obj->filtees_loaded = true;
2777 obj->filtees_loading = false;
2778 }
2779
2780 static int
process_needed(Obj_Entry * obj,Needed_Entry * needed,int flags)2781 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
2782 {
2783 Obj_Entry *obj1;
2784
2785 for (; needed != NULL; needed = needed->next) {
2786 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1,
2787 obj, flags & ~RTLD_LO_NOLOAD);
2788 if (obj1 == NULL && !ld_tracing &&
2789 (flags & RTLD_LO_FILTEES) == 0)
2790 return (-1);
2791 }
2792 return (0);
2793 }
2794
2795 /*
2796 * Given a shared object, traverse its list of needed objects, and load
2797 * each of them. Returns 0 on success. Generates an error message and
2798 * returns -1 on failure.
2799 */
2800 static int
load_needed_objects(Obj_Entry * first,int flags)2801 load_needed_objects(Obj_Entry *first, int flags)
2802 {
2803 Obj_Entry *obj;
2804
2805 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
2806 if (obj->marker)
2807 continue;
2808 if (process_needed(obj, obj->needed, flags) == -1)
2809 return (-1);
2810 }
2811 return (0);
2812 }
2813
2814 static int
load_preload_objects(const char * penv,bool isfd)2815 load_preload_objects(const char *penv, bool isfd)
2816 {
2817 Obj_Entry *obj;
2818 const char *name;
2819 size_t len;
2820 char savech, *p, *psave;
2821 int fd;
2822 static const char delim[] = " \t:;";
2823
2824 if (penv == NULL)
2825 return (0);
2826
2827 p = psave = xstrdup(penv);
2828 p += strspn(p, delim);
2829 while (*p != '\0') {
2830 len = strcspn(p, delim);
2831
2832 savech = p[len];
2833 p[len] = '\0';
2834 if (isfd) {
2835 name = NULL;
2836 fd = parse_integer(p);
2837 if (fd == -1) {
2838 free(psave);
2839 return (-1);
2840 }
2841 } else {
2842 name = p;
2843 fd = -1;
2844 }
2845
2846 obj = load_object(name, fd, NULL, 0);
2847 if (obj == NULL) {
2848 free(psave);
2849 return (-1); /* XXX - cleanup */
2850 }
2851 obj->z_interpose = true;
2852 p[len] = savech;
2853 p += len;
2854 p += strspn(p, delim);
2855 }
2856 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2857
2858 free(psave);
2859 return (0);
2860 }
2861
2862 static const char *
printable_path(const char * path)2863 printable_path(const char *path)
2864 {
2865 return (path == NULL ? "<unknown>" : path);
2866 }
2867
2868 /*
2869 * Load a shared object into memory, if it is not already loaded. The
2870 * object may be specified by name or by user-supplied file descriptor
2871 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2872 * duplicate is.
2873 *
2874 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2875 * on failure.
2876 */
2877 static Obj_Entry *
load_object(const char * name,int fd_u,const Obj_Entry * refobj,int flags)2878 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2879 {
2880 Obj_Entry *obj;
2881 int fd;
2882 struct stat sb;
2883 char *path;
2884
2885 fd = -1;
2886 if (name != NULL) {
2887 TAILQ_FOREACH(obj, &obj_list, next) {
2888 if (obj->marker || obj->doomed)
2889 continue;
2890 if (object_match_name(obj, name))
2891 return (obj);
2892 }
2893
2894 path = find_library(name, refobj, &fd);
2895 if (path == NULL)
2896 return (NULL);
2897 } else
2898 path = NULL;
2899
2900 if (fd >= 0) {
2901 /*
2902 * search_library_pathfds() opens a fresh file descriptor for
2903 * the library, so there is no need to dup().
2904 */
2905 } else if (fd_u == -1) {
2906 /*
2907 * If we didn't find a match by pathname, or the name is not
2908 * supplied, open the file and check again by device and inode.
2909 * This avoids false mismatches caused by multiple links or ".."
2910 * in pathnames.
2911 *
2912 * To avoid a race, we open the file and use fstat() rather than
2913 * using stat().
2914 */
2915 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) {
2916 fd = try_fds_open(path, ld_library_dirs);
2917 if (fd == -1) {
2918 _rtld_error("Cannot open \"%s\"", path);
2919 free(path);
2920 return (NULL);
2921 }
2922 }
2923 } else {
2924 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0);
2925 if (fd == -1) {
2926 _rtld_error("Cannot dup fd");
2927 free(path);
2928 return (NULL);
2929 }
2930 }
2931 if (fstat(fd, &sb) == -1) {
2932 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2933 close(fd);
2934 free(path);
2935 return (NULL);
2936 }
2937 TAILQ_FOREACH(obj, &obj_list, next) {
2938 if (obj->marker || obj->doomed)
2939 continue;
2940 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2941 break;
2942 }
2943 if (obj != NULL) {
2944 if (name != NULL)
2945 object_add_name(obj, name);
2946 free(path);
2947 close(fd);
2948 return (obj);
2949 }
2950 if (flags & RTLD_LO_NOLOAD) {
2951 free(path);
2952 close(fd);
2953 return (NULL);
2954 }
2955
2956 /* First use of this object, so we must map it in */
2957 obj = do_load_object(fd, name, path, &sb, flags);
2958 if (obj == NULL)
2959 free(path);
2960 close(fd);
2961
2962 return (obj);
2963 }
2964
2965 static Obj_Entry *
do_load_object(int fd,const char * name,char * path,struct stat * sbp,int flags)2966 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2967 int flags)
2968 {
2969 Obj_Entry *obj;
2970 struct statfs fs;
2971
2972 /*
2973 * First, make sure that environment variables haven't been
2974 * used to circumvent the noexec flag on a filesystem.
2975 * We ignore fstatfs(2) failures, since fd might reference
2976 * not a file, e.g. shmfd.
2977 */
2978 if (dangerous_ld_env && fstatfs(fd, &fs) == 0 &&
2979 (fs.f_flags & MNT_NOEXEC) != 0) {
2980 _rtld_error("Cannot execute objects on %s", fs.f_mntonname);
2981 return (NULL);
2982 }
2983
2984 dbg("loading \"%s\"", printable_path(path));
2985 obj = map_object(fd, printable_path(path), sbp, false);
2986 if (obj == NULL)
2987 return (NULL);
2988
2989 /*
2990 * If DT_SONAME is present in the object, digest_dynamic2 already
2991 * added it to the object names.
2992 */
2993 if (name != NULL)
2994 object_add_name(obj, name);
2995 obj->path = path;
2996 if (!digest_dynamic(obj, 0))
2997 goto errp;
2998 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2999 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
3000 if (obj->z_pie && (flags & RTLD_LO_TRACE) == 0) {
3001 dbg("refusing to load PIE executable \"%s\"", obj->path);
3002 _rtld_error("Cannot load PIE binary %s as DSO", obj->path);
3003 goto errp;
3004 }
3005 if (obj->z_noopen &&
3006 (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == RTLD_LO_DLOPEN) {
3007 dbg("refusing to load non-loadable \"%s\"", obj->path);
3008 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
3009 goto errp;
3010 }
3011
3012 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0;
3013 TAILQ_INSERT_TAIL(&obj_list, obj, next);
3014 obj_count++;
3015 obj_loads++;
3016 linkmap_add(obj); /* for GDB & dlinfo() */
3017 max_stack_flags |= obj->stack_flags;
3018
3019 dbg(" %p .. %p: %s", obj->mapbase, obj->mapbase + obj->mapsize - 1,
3020 obj->path);
3021 if (obj->textrel)
3022 dbg(" WARNING: %s has impure text", obj->path);
3023 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
3024 obj->path);
3025
3026 return (obj);
3027
3028 errp:
3029 munmap(obj->mapbase, obj->mapsize);
3030 obj_free(obj);
3031 return (NULL);
3032 }
3033
3034 static int
load_kpreload(const void * addr)3035 load_kpreload(const void *addr)
3036 {
3037 Obj_Entry *obj;
3038 const Elf_Ehdr *ehdr;
3039 const Elf_Phdr *phdr, *phlimit, *phdyn, *seg0, *segn;
3040 static const char kname[] = "[vdso]";
3041
3042 ehdr = addr;
3043 if (!check_elf_headers(ehdr, "kpreload"))
3044 return (-1);
3045 obj = obj_new();
3046 phdr = (const Elf_Phdr *)((const char *)addr + ehdr->e_phoff);
3047 obj->phdr = phdr;
3048 obj->phnum = ehdr->e_phnum;
3049 phlimit = phdr + ehdr->e_phnum;
3050 seg0 = segn = NULL;
3051
3052 for (; phdr < phlimit; phdr++) {
3053 switch (phdr->p_type) {
3054 case PT_DYNAMIC:
3055 phdyn = phdr;
3056 break;
3057 case PT_GNU_STACK:
3058 /* Absense of PT_GNU_STACK implies stack_flags == 0. */
3059 obj->stack_flags = phdr->p_flags;
3060 break;
3061 case PT_LOAD:
3062 if (seg0 == NULL || seg0->p_vaddr > phdr->p_vaddr)
3063 seg0 = phdr;
3064 if (segn == NULL ||
3065 segn->p_vaddr + segn->p_memsz <
3066 phdr->p_vaddr + phdr->p_memsz)
3067 segn = phdr;
3068 break;
3069 }
3070 }
3071
3072 obj->mapbase = __DECONST(caddr_t, addr);
3073 obj->mapsize = segn->p_vaddr + segn->p_memsz;
3074 obj->vaddrbase = 0;
3075 obj->relocbase = obj->mapbase;
3076
3077 object_add_name(obj, kname);
3078 obj->path = xstrdup(kname);
3079 obj->dynamic = (const Elf_Dyn *)(obj->relocbase + phdyn->p_vaddr);
3080
3081 if (!digest_dynamic(obj, 0)) {
3082 obj_free(obj);
3083 return (-1);
3084 }
3085
3086 /*
3087 * We assume that kernel-preloaded object does not need
3088 * relocation. It is currently written into read-only page,
3089 * handling relocations would mean we need to allocate at
3090 * least one additional page per AS.
3091 */
3092 dbg("%s mapbase %p phdrs %p PT_LOAD phdr %p vaddr %p dynamic %p",
3093 obj->path, obj->mapbase, obj->phdr, seg0,
3094 obj->relocbase + seg0->p_vaddr, obj->dynamic);
3095
3096 TAILQ_INSERT_TAIL(&obj_list, obj, next);
3097 obj_count++;
3098 obj_loads++;
3099 linkmap_add(obj); /* for GDB & dlinfo() */
3100 max_stack_flags |= obj->stack_flags;
3101
3102 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
3103 obj->path);
3104 return (0);
3105 }
3106
3107 Obj_Entry *
obj_from_addr(const void * addr)3108 obj_from_addr(const void *addr)
3109 {
3110 Obj_Entry *obj;
3111
3112 TAILQ_FOREACH(obj, &obj_list, next) {
3113 if (obj->marker)
3114 continue;
3115 if (addr < (void *)obj->mapbase)
3116 continue;
3117 if (addr < (void *)(obj->mapbase + obj->mapsize))
3118 return obj;
3119 }
3120 return (NULL);
3121 }
3122
3123 static void
preinit_main(void)3124 preinit_main(void)
3125 {
3126 uintptr_t *preinit_addr;
3127 int index;
3128
3129 preinit_addr = obj_main->preinit_array;
3130 if (preinit_addr == NULL)
3131 return;
3132
3133 for (index = 0; index < obj_main->preinit_array_num; index++) {
3134 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
3135 dbg("calling preinit function for %s at %p",
3136 obj_main->path, (void *)preinit_addr[index]);
3137 LD_UTRACE(UTRACE_INIT_CALL, obj_main,
3138 (void *)preinit_addr[index], 0, 0, obj_main->path);
3139 call_init_pointer(obj_main, preinit_addr[index]);
3140 }
3141 }
3142 }
3143
3144 /*
3145 * Call the finalization functions for each of the objects in "list"
3146 * belonging to the DAG of "root" and referenced once. If NULL "root"
3147 * is specified, every finalization function will be called regardless
3148 * of the reference count and the list elements won't be freed. All of
3149 * the objects are expected to have non-NULL fini functions.
3150 */
3151 static void
objlist_call_fini(Objlist * list,Obj_Entry * root,RtldLockState * lockstate)3152 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
3153 {
3154 Objlist_Entry *elm;
3155 struct dlerror_save *saved_msg;
3156 uintptr_t *fini_addr;
3157 int index;
3158
3159 assert(root == NULL || root->refcount == 1);
3160
3161 if (root != NULL)
3162 root->doomed = true;
3163
3164 /*
3165 * Preserve the current error message since a fini function might
3166 * call into the dynamic linker and overwrite it.
3167 */
3168 saved_msg = errmsg_save();
3169 do {
3170 STAILQ_FOREACH(elm, list, link) {
3171 if (root != NULL &&
3172 (elm->obj->refcount != 1 ||
3173 objlist_find(&root->dagmembers, elm->obj) ==
3174 NULL))
3175 continue;
3176 /* Remove object from fini list to prevent recursive
3177 * invocation. */
3178 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
3179 /* Ensure that new references cannot be acquired. */
3180 elm->obj->doomed = true;
3181
3182 hold_object(elm->obj);
3183 lock_release(rtld_bind_lock, lockstate);
3184 /*
3185 * It is legal to have both DT_FINI and DT_FINI_ARRAY
3186 * defined. When this happens, DT_FINI_ARRAY is
3187 * processed first.
3188 */
3189 fini_addr = elm->obj->fini_array;
3190 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
3191 for (index = elm->obj->fini_array_num - 1;
3192 index >= 0; index--) {
3193 if (fini_addr[index] != 0 &&
3194 fini_addr[index] != 1 &&
3195 fini_addr[index] != (Elf_Addr)-1) {
3196 dbg("calling fini function for %s at %p",
3197 elm->obj->path,
3198 (void *)fini_addr[index]);
3199 LD_UTRACE(UTRACE_FINI_CALL,
3200 elm->obj,
3201 (void *)fini_addr[index], 0,
3202 0, elm->obj->path);
3203 call_initfini_pointer(elm->obj,
3204 fini_addr[index]);
3205 }
3206 }
3207 }
3208 if (elm->obj->fini != 0) {
3209 dbg("calling fini function for %s at %p",
3210 elm->obj->path, (void *)elm->obj->fini);
3211 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
3212 (void *)elm->obj->fini, 0, 0,
3213 elm->obj->path);
3214 call_initfini_pointer(elm->obj, elm->obj->fini);
3215 }
3216 wlock_acquire(rtld_bind_lock, lockstate);
3217 unhold_object(elm->obj);
3218 /* No need to free anything if process is going down. */
3219 if (root != NULL)
3220 free(elm);
3221 /*
3222 * We must restart the list traversal after every fini
3223 * call because a dlclose() call from the fini function
3224 * or from another thread might have modified the
3225 * reference counts.
3226 */
3227 break;
3228 }
3229 } while (elm != NULL);
3230 errmsg_restore(saved_msg);
3231 }
3232
3233 /*
3234 * Call the initialization functions for each of the objects in
3235 * "list". All of the objects are expected to have non-NULL init
3236 * functions.
3237 */
3238 static void
objlist_call_init(Objlist * list,RtldLockState * lockstate)3239 objlist_call_init(Objlist *list, RtldLockState *lockstate)
3240 {
3241 Objlist_Entry *elm;
3242 Obj_Entry *obj;
3243 struct dlerror_save *saved_msg;
3244 uintptr_t *init_addr;
3245 void (*reg)(void (*)(void));
3246 int index;
3247
3248 /*
3249 * Clean init_scanned flag so that objects can be rechecked and
3250 * possibly initialized earlier if any of vectors called below
3251 * cause the change by using dlopen.
3252 */
3253 TAILQ_FOREACH(obj, &obj_list, next) {
3254 if (obj->marker)
3255 continue;
3256 obj->init_scanned = false;
3257 }
3258
3259 /*
3260 * Preserve the current error message since an init function might
3261 * call into the dynamic linker and overwrite it.
3262 */
3263 saved_msg = errmsg_save();
3264 STAILQ_FOREACH(elm, list, link) {
3265 if (elm->obj->init_done) /* Initialized early. */
3266 continue;
3267 /*
3268 * Race: other thread might try to use this object before
3269 * current one completes the initialization. Not much can be
3270 * done here without better locking.
3271 */
3272 elm->obj->init_done = true;
3273 hold_object(elm->obj);
3274 reg = NULL;
3275 if (elm->obj == obj_main && obj_main->crt_no_init) {
3276 reg = (void (*)(void (*)(void)))
3277 get_program_var_addr("__libc_atexit", lockstate);
3278 }
3279 lock_release(rtld_bind_lock, lockstate);
3280 if (reg != NULL) {
3281 reg(rtld_exit);
3282 rtld_exit_ptr = rtld_nop_exit;
3283 }
3284
3285 /*
3286 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
3287 * When this happens, DT_INIT is processed first.
3288 */
3289 if (elm->obj->init != 0) {
3290 dbg("calling init function for %s at %p",
3291 elm->obj->path, (void *)elm->obj->init);
3292 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
3293 (void *)elm->obj->init, 0, 0, elm->obj->path);
3294 call_init_pointer(elm->obj, elm->obj->init);
3295 }
3296 init_addr = elm->obj->init_array;
3297 if (init_addr != NULL) {
3298 for (index = 0; index < elm->obj->init_array_num;
3299 index++) {
3300 if (init_addr[index] != 0 &&
3301 init_addr[index] != 1 &&
3302 init_addr[index] != (Elf_Addr)-1) {
3303 dbg("calling init function for %s at %p",
3304 elm->obj->path,
3305 (void *)init_addr[index]);
3306 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
3307 (void *)init_addr[index], 0, 0,
3308 elm->obj->path);
3309 call_init_pointer(elm->obj,
3310 init_addr[index]);
3311 }
3312 }
3313 }
3314 wlock_acquire(rtld_bind_lock, lockstate);
3315 unhold_object(elm->obj);
3316 }
3317 errmsg_restore(saved_msg);
3318 }
3319
3320 static void
objlist_clear(Objlist * list)3321 objlist_clear(Objlist *list)
3322 {
3323 Objlist_Entry *elm;
3324
3325 while (!STAILQ_EMPTY(list)) {
3326 elm = STAILQ_FIRST(list);
3327 STAILQ_REMOVE_HEAD(list, link);
3328 free(elm);
3329 }
3330 }
3331
3332 static Objlist_Entry *
objlist_find(Objlist * list,const Obj_Entry * obj)3333 objlist_find(Objlist *list, const Obj_Entry *obj)
3334 {
3335 Objlist_Entry *elm;
3336
3337 STAILQ_FOREACH(elm, list, link)
3338 if (elm->obj == obj)
3339 return elm;
3340 return (NULL);
3341 }
3342
3343 static void
objlist_init(Objlist * list)3344 objlist_init(Objlist *list)
3345 {
3346 STAILQ_INIT(list);
3347 }
3348
3349 static void
objlist_push_head(Objlist * list,Obj_Entry * obj)3350 objlist_push_head(Objlist *list, Obj_Entry *obj)
3351 {
3352 Objlist_Entry *elm;
3353
3354 elm = NEW(Objlist_Entry);
3355 elm->obj = obj;
3356 STAILQ_INSERT_HEAD(list, elm, link);
3357 }
3358
3359 static void
objlist_push_tail(Objlist * list,Obj_Entry * obj)3360 objlist_push_tail(Objlist *list, Obj_Entry *obj)
3361 {
3362 Objlist_Entry *elm;
3363
3364 elm = NEW(Objlist_Entry);
3365 elm->obj = obj;
3366 STAILQ_INSERT_TAIL(list, elm, link);
3367 }
3368
3369 static void
objlist_put_after(Objlist * list,Obj_Entry * listobj,Obj_Entry * obj)3370 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj)
3371 {
3372 Objlist_Entry *elm, *listelm;
3373
3374 STAILQ_FOREACH(listelm, list, link) {
3375 if (listelm->obj == listobj)
3376 break;
3377 }
3378 elm = NEW(Objlist_Entry);
3379 elm->obj = obj;
3380 if (listelm != NULL)
3381 STAILQ_INSERT_AFTER(list, listelm, elm, link);
3382 else
3383 STAILQ_INSERT_TAIL(list, elm, link);
3384 }
3385
3386 static void
objlist_remove(Objlist * list,Obj_Entry * obj)3387 objlist_remove(Objlist *list, Obj_Entry *obj)
3388 {
3389 Objlist_Entry *elm;
3390
3391 if ((elm = objlist_find(list, obj)) != NULL) {
3392 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
3393 free(elm);
3394 }
3395 }
3396
3397 /*
3398 * Relocate dag rooted in the specified object.
3399 * Returns 0 on success, or -1 on failure.
3400 */
3401
3402 static int
relocate_object_dag(Obj_Entry * root,bool bind_now,Obj_Entry * rtldobj,int flags,RtldLockState * lockstate)3403 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
3404 int flags, RtldLockState *lockstate)
3405 {
3406 Objlist_Entry *elm;
3407 int error;
3408
3409 error = 0;
3410 STAILQ_FOREACH(elm, &root->dagmembers, link) {
3411 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
3412 lockstate);
3413 if (error == -1)
3414 break;
3415 }
3416 return (error);
3417 }
3418
3419 /*
3420 * Prepare for, or clean after, relocating an object marked with
3421 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only
3422 * segments are remapped read-write. After relocations are done, the
3423 * segment's permissions are returned back to the modes specified in
3424 * the phdrs. If any relocation happened, or always for wired
3425 * program, COW is triggered.
3426 */
3427 static int
reloc_textrel_prot(Obj_Entry * obj,bool before)3428 reloc_textrel_prot(Obj_Entry *obj, bool before)
3429 {
3430 const Elf_Phdr *ph;
3431 void *base;
3432 size_t sz;
3433 int prot;
3434
3435 for (ph = obj->phdr; ph < obj->phdr + obj->phnum; ph++) {
3436 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0)
3437 continue;
3438 base = obj->relocbase + rtld_trunc_page(ph->p_vaddr);
3439 sz = rtld_round_page(ph->p_vaddr + ph->p_filesz) -
3440 rtld_trunc_page(ph->p_vaddr);
3441 prot = before ? (PROT_READ | PROT_WRITE) :
3442 convert_prot(ph->p_flags);
3443 if (mprotect(base, sz, prot) == -1) {
3444 _rtld_error("%s: Cannot write-%sable text segment: %s",
3445 obj->path, before ? "en" : "dis",
3446 rtld_strerror(errno));
3447 return (-1);
3448 }
3449 }
3450 return (0);
3451 }
3452
3453 /* Process RELR relative relocations. */
3454 static void
reloc_relr(Obj_Entry * obj)3455 reloc_relr(Obj_Entry *obj)
3456 {
3457 const Elf_Relr *relr, *relrlim;
3458 Elf_Addr *where;
3459
3460 relrlim = (const Elf_Relr *)((const char *)obj->relr + obj->relrsize);
3461 for (relr = obj->relr; relr < relrlim; relr++) {
3462 Elf_Relr entry = *relr;
3463
3464 if ((entry & 1) == 0) {
3465 where = (Elf_Addr *)(obj->relocbase + entry);
3466 *where++ += (Elf_Addr)obj->relocbase;
3467 } else {
3468 for (long i = 0; (entry >>= 1) != 0; i++)
3469 if ((entry & 1) != 0)
3470 where[i] += (Elf_Addr)obj->relocbase;
3471 where += CHAR_BIT * sizeof(Elf_Relr) - 1;
3472 }
3473 }
3474 }
3475
3476 /*
3477 * Relocate single object.
3478 * Returns 0 on success, or -1 on failure.
3479 */
3480 static int
relocate_object(Obj_Entry * obj,bool bind_now,Obj_Entry * rtldobj,int flags,RtldLockState * lockstate)3481 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, int flags,
3482 RtldLockState *lockstate)
3483 {
3484 if (obj->relocated)
3485 return (0);
3486 obj->relocated = true;
3487 if (obj != rtldobj)
3488 dbg("relocating \"%s\"", obj->path);
3489
3490 if (obj->symtab == NULL || obj->strtab == NULL ||
3491 !(obj->valid_hash_sysv || obj->valid_hash_gnu))
3492 dbg("object %s has no run-time symbol table", obj->path);
3493
3494 /* There are relocations to the write-protected text segment. */
3495 if (obj->textrel && reloc_textrel_prot(obj, true) != 0)
3496 return (-1);
3497
3498 /* Process the non-PLT non-IFUNC relocations. */
3499 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
3500 return (-1);
3501 reloc_relr(obj);
3502
3503 /* Re-protected the text segment. */
3504 if (obj->textrel && reloc_textrel_prot(obj, false) != 0)
3505 return (-1);
3506
3507 /* Set the special PLT or GOT entries. */
3508 init_pltgot(obj);
3509
3510 /* Process the PLT relocations. */
3511 if (reloc_plt(obj, flags, lockstate) == -1)
3512 return (-1);
3513 /* Relocate the jump slots if we are doing immediate binding. */
3514 if ((obj->bind_now || bind_now) &&
3515 reloc_jmpslots(obj, flags, lockstate) == -1)
3516 return (-1);
3517
3518 if (obj != rtldobj && !obj->mainprog && obj_enforce_relro(obj) == -1)
3519 return (-1);
3520
3521 /*
3522 * Set up the magic number and version in the Obj_Entry. These
3523 * were checked in the crt1.o from the original ElfKit, so we
3524 * set them for backward compatibility.
3525 */
3526 obj->magic = RTLD_MAGIC;
3527 obj->version = RTLD_VERSION;
3528
3529 return (0);
3530 }
3531
3532 /*
3533 * Relocate newly-loaded shared objects. The argument is a pointer to
3534 * the Obj_Entry for the first such object. All objects from the first
3535 * to the end of the list of objects are relocated. Returns 0 on success,
3536 * or -1 on failure.
3537 */
3538 static int
relocate_objects(Obj_Entry * first,bool bind_now,Obj_Entry * rtldobj,int flags,RtldLockState * lockstate)3539 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, int flags,
3540 RtldLockState *lockstate)
3541 {
3542 Obj_Entry *obj;
3543 int error;
3544
3545 for (error = 0, obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
3546 if (obj->marker)
3547 continue;
3548 error = relocate_object(obj, bind_now, rtldobj, flags,
3549 lockstate);
3550 if (error == -1)
3551 break;
3552 }
3553 return (error);
3554 }
3555
3556 /*
3557 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
3558 * referencing STT_GNU_IFUNC symbols is postponed till the other
3559 * relocations are done. The indirect functions specified as
3560 * ifunc are allowed to call other symbols, so we need to have
3561 * objects relocated before asking for resolution from indirects.
3562 *
3563 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
3564 * instead of the usual lazy handling of PLT slots. It is
3565 * consistent with how GNU does it.
3566 */
3567 static int
resolve_object_ifunc(Obj_Entry * obj,bool bind_now,int flags,RtldLockState * lockstate)3568 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
3569 RtldLockState *lockstate)
3570 {
3571 if (obj->ifuncs_resolved)
3572 return (0);
3573 obj->ifuncs_resolved = true;
3574 if (!obj->irelative && !obj->irelative_nonplt &&
3575 !((obj->bind_now || bind_now) && obj->gnu_ifunc) &&
3576 !obj->non_plt_gnu_ifunc)
3577 return (0);
3578 if (obj_disable_relro(obj) == -1 ||
3579 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) ||
3580 (obj->irelative_nonplt &&
3581 reloc_iresolve_nonplt(obj, lockstate) == -1) ||
3582 ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
3583 reloc_gnu_ifunc(obj, flags, lockstate) == -1) ||
3584 (obj->non_plt_gnu_ifunc &&
3585 reloc_non_plt(obj, &obj_rtld, flags | SYMLOOK_IFUNC,
3586 lockstate) == -1) ||
3587 obj_enforce_relro(obj) == -1)
3588 return (-1);
3589 return (0);
3590 }
3591
3592 static int
initlist_objects_ifunc(Objlist * list,bool bind_now,int flags,RtldLockState * lockstate)3593 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
3594 RtldLockState *lockstate)
3595 {
3596 Objlist_Entry *elm;
3597 Obj_Entry *obj;
3598
3599 STAILQ_FOREACH(elm, list, link) {
3600 obj = elm->obj;
3601 if (obj->marker)
3602 continue;
3603 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1)
3604 return (-1);
3605 }
3606 return (0);
3607 }
3608
3609 /*
3610 * Cleanup procedure. It will be called (by the atexit mechanism) just
3611 * before the process exits.
3612 */
3613 static void
rtld_exit(void)3614 rtld_exit(void)
3615 {
3616 RtldLockState lockstate;
3617
3618 wlock_acquire(rtld_bind_lock, &lockstate);
3619 dbg("rtld_exit()");
3620 objlist_call_fini(&list_fini, NULL, &lockstate);
3621 /* No need to remove the items from the list, since we are exiting. */
3622 if (!libmap_disable)
3623 lm_fini();
3624 lock_release(rtld_bind_lock, &lockstate);
3625 }
3626
3627 static void
rtld_nop_exit(void)3628 rtld_nop_exit(void)
3629 {
3630 }
3631
3632 /*
3633 * Parse string of the format '#number/name", where number must be a
3634 * decimal number of the opened file descriptor listed in
3635 * LD_LIBRARY_PATH_FDS. If successful, tries to open dso name under
3636 * dirfd number and returns resulting fd.
3637 * On any error, returns -1.
3638 */
3639 static int
try_fds_open(const char * name,const char * path)3640 try_fds_open(const char *name, const char *path)
3641 {
3642 const char *n;
3643 char *envcopy, *fdstr, *last_token, *ncopy;
3644 size_t len;
3645 int fd, dirfd, dirfd_path;
3646
3647 if (!trust || name[0] != '#' || path == NULL)
3648 return (-1);
3649
3650 name++;
3651 n = strchr(name, '/');
3652 if (n == NULL)
3653 return (-1);
3654 len = n - name;
3655 ncopy = xmalloc(len + 1);
3656 memcpy(ncopy, name, len);
3657 ncopy[len] = '\0';
3658 dirfd = parse_integer(ncopy);
3659 free(ncopy);
3660 if (dirfd == -1)
3661 return (-1);
3662
3663 envcopy = xstrdup(path);
3664 dirfd_path = -1;
3665 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL;
3666 fdstr = strtok_r(NULL, ":", &last_token)) {
3667 dirfd_path = parse_integer(fdstr);
3668 if (dirfd_path == dirfd)
3669 break;
3670 }
3671 free(envcopy);
3672 if (dirfd_path != dirfd)
3673 return (-1);
3674
3675 fd = __sys_openat(dirfd, n + 1, O_RDONLY | O_CLOEXEC | O_VERIFY);
3676 return (fd);
3677 }
3678
3679 /*
3680 * Iterate over a search path, translate each element, and invoke the
3681 * callback on the result.
3682 */
3683 static void *
path_enumerate(const char * path,path_enum_proc callback,const char * refobj_path,void * arg)3684 path_enumerate(const char *path, path_enum_proc callback,
3685 const char *refobj_path, void *arg)
3686 {
3687 const char *trans;
3688 if (path == NULL)
3689 return (NULL);
3690
3691 path += strspn(path, ":;");
3692 while (*path != '\0') {
3693 size_t len;
3694 char *res;
3695
3696 len = strcspn(path, ":;");
3697 trans = lm_findn(refobj_path, path, len);
3698 if (trans)
3699 res = callback(trans, strlen(trans), arg);
3700 else
3701 res = callback(path, len, arg);
3702
3703 if (res != NULL)
3704 return (res);
3705
3706 path += len;
3707 path += strspn(path, ":;");
3708 }
3709
3710 return (NULL);
3711 }
3712
3713 struct try_library_args {
3714 const char *name;
3715 size_t namelen;
3716 char *buffer;
3717 size_t buflen;
3718 int fd;
3719 };
3720
3721 static void *
try_library_path(const char * dir,size_t dirlen,void * param)3722 try_library_path(const char *dir, size_t dirlen, void *param)
3723 {
3724 struct try_library_args *arg;
3725 int fd;
3726
3727 arg = param;
3728 if (*dir == '/' || trust) {
3729 char *pathname;
3730
3731 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
3732 return (NULL);
3733
3734 pathname = arg->buffer;
3735 strncpy(pathname, dir, dirlen);
3736 pathname[dirlen] = '/';
3737 strcpy(pathname + dirlen + 1, arg->name);
3738
3739 dbg(" Trying \"%s\"", pathname);
3740 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY);
3741 if (fd >= 0) {
3742 dbg(" Opened \"%s\", fd %d", pathname, fd);
3743 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
3744 strcpy(pathname, arg->buffer);
3745 arg->fd = fd;
3746 return (pathname);
3747 } else {
3748 dbg(" Failed to open \"%s\": %s", pathname,
3749 rtld_strerror(errno));
3750 }
3751 }
3752 return (NULL);
3753 }
3754
3755 static char *
search_library_path(const char * name,const char * path,const char * refobj_path,int * fdp)3756 search_library_path(const char *name, const char *path, const char *refobj_path,
3757 int *fdp)
3758 {
3759 char *p;
3760 struct try_library_args arg;
3761
3762 if (path == NULL)
3763 return (NULL);
3764
3765 arg.name = name;
3766 arg.namelen = strlen(name);
3767 arg.buffer = xmalloc(PATH_MAX);
3768 arg.buflen = PATH_MAX;
3769 arg.fd = -1;
3770
3771 p = path_enumerate(path, try_library_path, refobj_path, &arg);
3772 *fdp = arg.fd;
3773
3774 free(arg.buffer);
3775
3776 return (p);
3777 }
3778
3779 /*
3780 * Finds the library with the given name using the directory descriptors
3781 * listed in the LD_LIBRARY_PATH_FDS environment variable.
3782 *
3783 * Returns a freshly-opened close-on-exec file descriptor for the library,
3784 * or -1 if the library cannot be found.
3785 */
3786 static char *
search_library_pathfds(const char * name,const char * path,int * fdp)3787 search_library_pathfds(const char *name, const char *path, int *fdp)
3788 {
3789 char *envcopy, *fdstr, *found, *last_token;
3790 size_t len;
3791 int dirfd, fd;
3792
3793 dbg("%s('%s', '%s', fdp)", __func__, name, path);
3794
3795 /* Don't load from user-specified libdirs into setuid binaries. */
3796 if (!trust)
3797 return (NULL);
3798
3799 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */
3800 if (path == NULL)
3801 return (NULL);
3802
3803 /* LD_LIBRARY_PATH_FDS only works with relative paths. */
3804 if (name[0] == '/') {
3805 dbg("Absolute path (%s) passed to %s", name, __func__);
3806 return (NULL);
3807 }
3808
3809 /*
3810 * Use strtok_r() to walk the FD:FD:FD list. This requires a local
3811 * copy of the path, as strtok_r rewrites separator tokens
3812 * with '\0'.
3813 */
3814 found = NULL;
3815 envcopy = xstrdup(path);
3816 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL;
3817 fdstr = strtok_r(NULL, ":", &last_token)) {
3818 dirfd = parse_integer(fdstr);
3819 if (dirfd < 0) {
3820 _rtld_error("failed to parse directory FD: '%s'",
3821 fdstr);
3822 break;
3823 }
3824 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY);
3825 if (fd >= 0) {
3826 *fdp = fd;
3827 len = strlen(fdstr) + strlen(name) + 3;
3828 found = xmalloc(len);
3829 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) <
3830 0) {
3831 _rtld_error("error generating '%d/%s'", dirfd,
3832 name);
3833 rtld_die();
3834 }
3835 dbg("open('%s') => %d", found, fd);
3836 break;
3837 }
3838 }
3839 free(envcopy);
3840
3841 return (found);
3842 }
3843
3844 int
dlclose(void * handle)3845 dlclose(void *handle)
3846 {
3847 RtldLockState lockstate;
3848 int error;
3849
3850 wlock_acquire(rtld_bind_lock, &lockstate);
3851 error = dlclose_locked(handle, &lockstate);
3852 lock_release(rtld_bind_lock, &lockstate);
3853 return (error);
3854 }
3855
3856 static int
dlclose_locked(void * handle,RtldLockState * lockstate)3857 dlclose_locked(void *handle, RtldLockState *lockstate)
3858 {
3859 Obj_Entry *root;
3860
3861 root = dlcheck(handle);
3862 if (root == NULL)
3863 return (-1);
3864 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
3865 root->path);
3866
3867 /* Unreference the object and its dependencies. */
3868 root->dl_refcount--;
3869
3870 if (root->refcount == 1) {
3871 /*
3872 * The object will be no longer referenced, so we must unload
3873 * it. First, call the fini functions.
3874 */
3875 objlist_call_fini(&list_fini, root, lockstate);
3876
3877 unref_dag(root);
3878
3879 /* Finish cleaning up the newly-unreferenced objects. */
3880 GDB_STATE(RT_DELETE, &root->linkmap);
3881 unload_object(root, lockstate);
3882 GDB_STATE(RT_CONSISTENT, NULL);
3883 } else
3884 unref_dag(root);
3885
3886 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
3887 return (0);
3888 }
3889
3890 char *
dlerror(void)3891 dlerror(void)
3892 {
3893 if (*(lockinfo.dlerror_seen()) != 0)
3894 return (NULL);
3895 *lockinfo.dlerror_seen() = 1;
3896 return (lockinfo.dlerror_loc());
3897 }
3898
3899 /*
3900 * This function is deprecated and has no effect.
3901 */
3902 void
dllockinit(void * context,void * (* _lock_create)(void * context)__unused,void (* _rlock_acquire)(void * lock)__unused,void (* _wlock_acquire)(void * lock)__unused,void (* _lock_release)(void * lock)__unused,void (* _lock_destroy)(void * lock)__unused,void (* context_destroy)(void * context))3903 dllockinit(void *context, void *(*_lock_create)(void *context)__unused,
3904 void (*_rlock_acquire)(void *lock) __unused,
3905 void (*_wlock_acquire)(void *lock) __unused,
3906 void (*_lock_release)(void *lock) __unused,
3907 void (*_lock_destroy)(void *lock) __unused,
3908 void (*context_destroy)(void *context))
3909 {
3910 static void *cur_context;
3911 static void (*cur_context_destroy)(void *);
3912
3913 /* Just destroy the context from the previous call, if necessary. */
3914 if (cur_context_destroy != NULL)
3915 cur_context_destroy(cur_context);
3916 cur_context = context;
3917 cur_context_destroy = context_destroy;
3918 }
3919
3920 void *
dlopen(const char * name,int mode)3921 dlopen(const char *name, int mode)
3922 {
3923 return (rtld_dlopen(name, -1, mode));
3924 }
3925
3926 void *
fdlopen(int fd,int mode)3927 fdlopen(int fd, int mode)
3928 {
3929 return (rtld_dlopen(NULL, fd, mode));
3930 }
3931
3932 static void *
rtld_dlopen(const char * name,int fd,int mode)3933 rtld_dlopen(const char *name, int fd, int mode)
3934 {
3935 RtldLockState lockstate;
3936 int lo_flags;
3937
3938 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
3939 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
3940 if (ld_tracing != NULL) {
3941 rlock_acquire(rtld_bind_lock, &lockstate);
3942 if (sigsetjmp(lockstate.env, 0) != 0)
3943 lock_upgrade(rtld_bind_lock, &lockstate);
3944 environ = __DECONST(char **,
3945 *get_program_var_addr("environ", &lockstate));
3946 lock_release(rtld_bind_lock, &lockstate);
3947 }
3948 lo_flags = RTLD_LO_DLOPEN;
3949 if (mode & RTLD_NODELETE)
3950 lo_flags |= RTLD_LO_NODELETE;
3951 if (mode & RTLD_NOLOAD)
3952 lo_flags |= RTLD_LO_NOLOAD;
3953 if (mode & RTLD_DEEPBIND)
3954 lo_flags |= RTLD_LO_DEEPBIND;
3955 if (ld_tracing != NULL)
3956 lo_flags |= RTLD_LO_TRACE | RTLD_LO_IGNSTLS;
3957
3958 return (dlopen_object(name, fd, obj_main, lo_flags,
3959 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
3960 }
3961
3962 static void
dlopen_cleanup(Obj_Entry * obj,RtldLockState * lockstate)3963 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate)
3964 {
3965 obj->dl_refcount--;
3966 unref_dag(obj);
3967 if (obj->refcount == 0)
3968 unload_object(obj, lockstate);
3969 }
3970
3971 static Obj_Entry *
dlopen_object(const char * name,int fd,Obj_Entry * refobj,int lo_flags,int mode,RtldLockState * lockstate)3972 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
3973 int mode, RtldLockState *lockstate)
3974 {
3975 Obj_Entry *obj;
3976 Objlist initlist;
3977 RtldLockState mlockstate;
3978 int result;
3979
3980 dbg(
3981 "dlopen_object name \"%s\" fd %d refobj \"%s\" lo_flags %#x mode %#x",
3982 name != NULL ? name : "<null>", fd,
3983 refobj == NULL ? "<null>" : refobj->path, lo_flags, mode);
3984 objlist_init(&initlist);
3985
3986 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
3987 wlock_acquire(rtld_bind_lock, &mlockstate);
3988 lockstate = &mlockstate;
3989 }
3990 GDB_STATE(RT_ADD, NULL);
3991
3992 obj = NULL;
3993 if (name == NULL && fd == -1) {
3994 obj = obj_main;
3995 obj->refcount++;
3996 } else {
3997 obj = load_object(name, fd, refobj, lo_flags);
3998 }
3999
4000 if (obj != NULL) {
4001 obj->dl_refcount++;
4002 if ((mode & RTLD_GLOBAL) != 0 &&
4003 objlist_find(&list_global, obj) == NULL)
4004 objlist_push_tail(&list_global, obj);
4005
4006 if (!obj->init_done) {
4007 /* We loaded something new and have to init something.
4008 */
4009 if ((lo_flags & RTLD_LO_DEEPBIND) != 0)
4010 obj->deepbind = true;
4011 result = 0;
4012 if ((lo_flags & (RTLD_LO_EARLY |
4013 RTLD_LO_IGNSTLS)) == 0 &&
4014 obj->static_tls && !allocate_tls_offset(obj)) {
4015 _rtld_error(
4016 "%s: No space available for static Thread Local Storage",
4017 obj->path);
4018 result = -1;
4019 }
4020 if (result != -1)
4021 result = load_needed_objects(obj,
4022 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY |
4023 RTLD_LO_IGNSTLS | RTLD_LO_TRACE));
4024 init_dag(obj);
4025 ref_dag(obj);
4026 if (result != -1)
4027 result = rtld_verify_versions(&obj->dagmembers);
4028 if (result != -1 && ld_tracing)
4029 goto trace;
4030 if (result == -1 || relocate_object_dag(obj,
4031 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
4032 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
4033 lockstate) == -1) {
4034 dlopen_cleanup(obj, lockstate);
4035 obj = NULL;
4036 } else if ((lo_flags & RTLD_LO_EARLY) != 0) {
4037 /*
4038 * Do not call the init functions for early
4039 * loaded filtees. The image is still not
4040 * initialized enough for them to work.
4041 *
4042 * Our object is found by the global object list
4043 * and will be ordered among all init calls done
4044 * right before transferring control to main.
4045 */
4046 } else {
4047 /* Make list of init functions to call. */
4048 initlist_for_loaded_obj(obj, obj, &initlist);
4049 }
4050 /*
4051 * Process all no_delete or global objects here, given
4052 * them own DAGs to prevent their dependencies from
4053 * being unloaded. This has to be done after we have
4054 * loaded all of the dependencies, so that we do not
4055 * miss any.
4056 */
4057 if (obj != NULL)
4058 process_z(obj);
4059 } else {
4060 /*
4061 * Bump the reference counts for objects on this DAG. If
4062 * this is the first dlopen() call for the object that
4063 * was already loaded as a dependency, initialize the
4064 * dag starting at it.
4065 */
4066 init_dag(obj);
4067 ref_dag(obj);
4068
4069 if ((lo_flags & RTLD_LO_TRACE) != 0)
4070 goto trace;
4071 }
4072 if (obj != NULL &&
4073 ((lo_flags & RTLD_LO_NODELETE) != 0 || obj->z_nodelete) &&
4074 !obj->ref_nodel) {
4075 dbg("obj %s nodelete", obj->path);
4076 ref_dag(obj);
4077 obj->z_nodelete = obj->ref_nodel = true;
4078 }
4079 }
4080
4081 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
4082 name);
4083 GDB_STATE(RT_CONSISTENT, obj ? &obj->linkmap : NULL);
4084
4085 if ((lo_flags & RTLD_LO_EARLY) == 0) {
4086 map_stacks_exec(lockstate);
4087 if (obj != NULL)
4088 distribute_static_tls(&initlist);
4089 }
4090
4091 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) ==
4092 RTLD_NOW, (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
4093 lockstate) == -1) {
4094 objlist_clear(&initlist);
4095 dlopen_cleanup(obj, lockstate);
4096 if (lockstate == &mlockstate)
4097 lock_release(rtld_bind_lock, lockstate);
4098 return (NULL);
4099 }
4100
4101 if ((lo_flags & RTLD_LO_EARLY) == 0) {
4102 /* Call the init functions. */
4103 objlist_call_init(&initlist, lockstate);
4104 }
4105 objlist_clear(&initlist);
4106 if (lockstate == &mlockstate)
4107 lock_release(rtld_bind_lock, lockstate);
4108 return (obj);
4109 trace:
4110 trace_loaded_objects(obj, false);
4111 if (lockstate == &mlockstate)
4112 lock_release(rtld_bind_lock, lockstate);
4113 exit(0);
4114 }
4115
4116 static void *
do_dlsym(void * handle,const char * name,void * retaddr,const Ver_Entry * ve,int flags)4117 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
4118 int flags)
4119 {
4120 DoneList donelist;
4121 const Obj_Entry *obj, *defobj;
4122 const Elf_Sym *def;
4123 SymLook req;
4124 RtldLockState lockstate;
4125 tls_index ti;
4126 void *sym;
4127 int res;
4128
4129 def = NULL;
4130 defobj = NULL;
4131 symlook_init(&req, name);
4132 req.ventry = ve;
4133 req.flags = flags | SYMLOOK_IN_PLT;
4134 req.lockstate = &lockstate;
4135
4136 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name);
4137 rlock_acquire(rtld_bind_lock, &lockstate);
4138 if (sigsetjmp(lockstate.env, 0) != 0) {
4139 lock_upgrade(rtld_bind_lock, &lockstate);
4140 free(req.donelist_mem);
4141 req.donelist_mem = NULL;
4142 }
4143 if (handle == NULL || handle == RTLD_NEXT || handle == RTLD_DEFAULT ||
4144 handle == RTLD_SELF) {
4145 if ((obj = obj_from_addr(retaddr)) == NULL) {
4146 _rtld_error("Cannot determine caller's shared object");
4147 lock_release(rtld_bind_lock, &lockstate);
4148 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
4149 return (NULL);
4150 }
4151 if (handle == NULL) { /* Just the caller's shared object. */
4152 res = symlook_obj(&req, obj);
4153 if (res == 0) {
4154 def = req.sym_out;
4155 defobj = req.defobj_out;
4156 }
4157 } else if (handle == RTLD_NEXT || /* Objects after caller's */
4158 handle == RTLD_SELF) { /* ... caller included */
4159 if (handle == RTLD_NEXT)
4160 obj = globallist_next(obj);
4161 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
4162 if (obj->marker)
4163 continue;
4164 res = symlook_obj(&req, obj);
4165 if (res == 0) {
4166 if (def == NULL ||
4167 (ld_dynamic_weak &&
4168 ELF_ST_BIND(
4169 req.sym_out->st_info) !=
4170 STB_WEAK)) {
4171 def = req.sym_out;
4172 defobj = req.defobj_out;
4173 if (!ld_dynamic_weak ||
4174 ELF_ST_BIND(def->st_info) !=
4175 STB_WEAK)
4176 break;
4177 }
4178 }
4179 }
4180 /*
4181 * Search the dynamic linker itself, and possibly
4182 * resolve the symbol from there. This is how the
4183 * application links to dynamic linker services such as
4184 * dlopen. Note that we ignore ld_dynamic_weak == false
4185 * case, always overriding weak symbols by rtld
4186 * definitions.
4187 */
4188 if (def == NULL ||
4189 ELF_ST_BIND(def->st_info) == STB_WEAK) {
4190 res = symlook_obj(&req, &obj_rtld);
4191 if (res == 0) {
4192 def = req.sym_out;
4193 defobj = req.defobj_out;
4194 }
4195 }
4196 } else {
4197 assert(handle == RTLD_DEFAULT);
4198 res = symlook_default(&req, obj);
4199 if (res == 0) {
4200 defobj = req.defobj_out;
4201 def = req.sym_out;
4202 }
4203 }
4204 } else {
4205 if ((obj = dlcheck(handle)) == NULL) {
4206 lock_release(rtld_bind_lock, &lockstate);
4207 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
4208 return (NULL);
4209 }
4210
4211 donelist_init(&donelist, &req);
4212 if (obj->mainprog) {
4213 /* Handle obtained by dlopen(NULL, ...) implies global
4214 * scope. */
4215 res = symlook_global(&req, &donelist);
4216 if (res == 0) {
4217 def = req.sym_out;
4218 defobj = req.defobj_out;
4219 }
4220 /*
4221 * Search the dynamic linker itself, and possibly
4222 * resolve the symbol from there. This is how the
4223 * application links to dynamic linker services such as
4224 * dlopen.
4225 */
4226 if (def == NULL ||
4227 ELF_ST_BIND(def->st_info) == STB_WEAK) {
4228 res = symlook_obj(&req, &obj_rtld);
4229 if (res == 0) {
4230 def = req.sym_out;
4231 defobj = req.defobj_out;
4232 }
4233 }
4234 } else {
4235 /* Search the whole DAG rooted at the given object. */
4236 res = symlook_list(&req, &obj->dagmembers, &donelist);
4237 if (res == 0) {
4238 def = req.sym_out;
4239 defobj = req.defobj_out;
4240 }
4241 }
4242 donelist_free(&donelist);
4243 }
4244
4245 if (def != NULL) {
4246 lock_release(rtld_bind_lock, &lockstate);
4247
4248 /*
4249 * The value required by the caller is derived from the value
4250 * of the symbol. this is simply the relocated value of the
4251 * symbol.
4252 */
4253 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
4254 sym = make_function_pointer(def, defobj);
4255 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
4256 sym = rtld_resolve_ifunc(defobj, def);
4257 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
4258 ti.ti_module = defobj->tlsindex;
4259 ti.ti_offset = def->st_value - TLS_DTV_OFFSET;
4260 sym = __tls_get_addr(&ti);
4261 } else
4262 sym = defobj->relocbase + def->st_value;
4263 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name);
4264 return (sym);
4265 }
4266
4267 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "",
4268 ve != NULL ? ve->name : "");
4269 lock_release(rtld_bind_lock, &lockstate);
4270 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
4271 return (NULL);
4272 }
4273
4274 void *
dlsym(void * handle,const char * name)4275 dlsym(void *handle, const char *name)
4276 {
4277 return (do_dlsym(handle, name, __builtin_return_address(0), NULL,
4278 SYMLOOK_DLSYM));
4279 }
4280
4281 dlfunc_t
dlfunc(void * handle,const char * name)4282 dlfunc(void *handle, const char *name)
4283 {
4284 union {
4285 void *d;
4286 dlfunc_t f;
4287 } rv;
4288
4289 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
4290 SYMLOOK_DLSYM);
4291 return (rv.f);
4292 }
4293
4294 void *
dlvsym(void * handle,const char * name,const char * version)4295 dlvsym(void *handle, const char *name, const char *version)
4296 {
4297 Ver_Entry ventry;
4298
4299 ventry.name = version;
4300 ventry.file = NULL;
4301 ventry.hash = elf_hash(version);
4302 ventry.flags = 0;
4303 return (do_dlsym(handle, name, __builtin_return_address(0), &ventry,
4304 SYMLOOK_DLSYM));
4305 }
4306
4307 int
_rtld_addr_phdr(const void * addr,struct dl_phdr_info * phdr_info)4308 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
4309 {
4310 const Obj_Entry *obj;
4311 RtldLockState lockstate;
4312
4313 rlock_acquire(rtld_bind_lock, &lockstate);
4314 obj = obj_from_addr(addr);
4315 if (obj == NULL) {
4316 _rtld_error("No shared object contains address");
4317 lock_release(rtld_bind_lock, &lockstate);
4318 return (0);
4319 }
4320 rtld_fill_dl_phdr_info(obj, phdr_info);
4321 lock_release(rtld_bind_lock, &lockstate);
4322 return (1);
4323 }
4324
4325 int
dladdr(const void * addr,Dl_info * info)4326 dladdr(const void *addr, Dl_info *info)
4327 {
4328 const Obj_Entry *obj;
4329 const Elf_Sym *def;
4330 void *symbol_addr;
4331 unsigned long symoffset;
4332 RtldLockState lockstate;
4333
4334 rlock_acquire(rtld_bind_lock, &lockstate);
4335 obj = obj_from_addr(addr);
4336 if (obj == NULL) {
4337 _rtld_error("No shared object contains address");
4338 lock_release(rtld_bind_lock, &lockstate);
4339 return (0);
4340 }
4341 info->dli_fname = obj->path;
4342 info->dli_fbase = obj->mapbase;
4343 info->dli_saddr = (void *)0;
4344 info->dli_sname = NULL;
4345
4346 /*
4347 * Walk the symbol list looking for the symbol whose address is
4348 * closest to the address sent in.
4349 */
4350 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
4351 def = obj->symtab + symoffset;
4352
4353 /*
4354 * For skip the symbol if st_shndx is either SHN_UNDEF or
4355 * SHN_COMMON.
4356 */
4357 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
4358 continue;
4359
4360 /*
4361 * If the symbol is greater than the specified address, or if it
4362 * is further away from addr than the current nearest symbol,
4363 * then reject it.
4364 */
4365 symbol_addr = obj->relocbase + def->st_value;
4366 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
4367 continue;
4368
4369 /* Update our idea of the nearest symbol. */
4370 info->dli_sname = obj->strtab + def->st_name;
4371 info->dli_saddr = symbol_addr;
4372
4373 /* Exact match? */
4374 if (info->dli_saddr == addr)
4375 break;
4376 }
4377 lock_release(rtld_bind_lock, &lockstate);
4378 return (1);
4379 }
4380
4381 int
dlinfo(void * handle,int request,void * p)4382 dlinfo(void *handle, int request, void *p)
4383 {
4384 const Obj_Entry *obj;
4385 RtldLockState lockstate;
4386 int error;
4387
4388 rlock_acquire(rtld_bind_lock, &lockstate);
4389
4390 if (handle == NULL || handle == RTLD_SELF) {
4391 void *retaddr;
4392
4393 retaddr = __builtin_return_address(0); /* __GNUC__ only */
4394 if ((obj = obj_from_addr(retaddr)) == NULL)
4395 _rtld_error("Cannot determine caller's shared object");
4396 } else
4397 obj = dlcheck(handle);
4398
4399 if (obj == NULL) {
4400 lock_release(rtld_bind_lock, &lockstate);
4401 return (-1);
4402 }
4403
4404 error = 0;
4405 switch (request) {
4406 case RTLD_DI_LINKMAP:
4407 *((struct link_map const **)p) = &obj->linkmap;
4408 break;
4409 case RTLD_DI_ORIGIN:
4410 error = rtld_dirname(obj->path, p);
4411 break;
4412
4413 case RTLD_DI_SERINFOSIZE:
4414 case RTLD_DI_SERINFO:
4415 error = do_search_info(obj, request, (struct dl_serinfo *)p);
4416 break;
4417
4418 default:
4419 _rtld_error("Invalid request %d passed to dlinfo()", request);
4420 error = -1;
4421 }
4422
4423 lock_release(rtld_bind_lock, &lockstate);
4424
4425 return (error);
4426 }
4427
4428 static void
rtld_fill_dl_phdr_info(const Obj_Entry * obj,struct dl_phdr_info * phdr_info)4429 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
4430 {
4431 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
4432 phdr_info->dlpi_name = obj->path;
4433 phdr_info->dlpi_phdr = obj->phdr;
4434 phdr_info->dlpi_phnum = obj->phnum;
4435 phdr_info->dlpi_tls_modid = obj->tlsindex;
4436 phdr_info->dlpi_tls_data = (char *)tls_get_addr_slow(_tcb_get(),
4437 obj->tlsindex, 0, true);
4438 phdr_info->dlpi_adds = obj_loads;
4439 phdr_info->dlpi_subs = obj_loads - obj_count;
4440 }
4441
4442 /*
4443 * It's completely UB to actually use this, so extreme caution is advised. It's
4444 * probably not what you want.
4445 */
4446 int
_dl_iterate_phdr_locked(__dl_iterate_hdr_callback callback,void * param)4447 _dl_iterate_phdr_locked(__dl_iterate_hdr_callback callback, void *param)
4448 {
4449 struct dl_phdr_info phdr_info;
4450 Obj_Entry *obj;
4451 int error;
4452
4453 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;
4454 obj = globallist_next(obj)) {
4455 rtld_fill_dl_phdr_info(obj, &phdr_info);
4456 error = callback(&phdr_info, sizeof(phdr_info), param);
4457 if (error != 0)
4458 return (error);
4459 }
4460
4461 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info);
4462 return (callback(&phdr_info, sizeof(phdr_info), param));
4463 }
4464
4465 int
dl_iterate_phdr(__dl_iterate_hdr_callback callback,void * param)4466 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
4467 {
4468 struct dl_phdr_info phdr_info;
4469 Obj_Entry *obj, marker;
4470 RtldLockState bind_lockstate, phdr_lockstate;
4471 int error;
4472
4473 init_marker(&marker);
4474 error = 0;
4475
4476 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
4477 wlock_acquire(rtld_bind_lock, &bind_lockstate);
4478 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) {
4479 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next);
4480 rtld_fill_dl_phdr_info(obj, &phdr_info);
4481 hold_object(obj);
4482 lock_release(rtld_bind_lock, &bind_lockstate);
4483
4484 error = callback(&phdr_info, sizeof phdr_info, param);
4485
4486 wlock_acquire(rtld_bind_lock, &bind_lockstate);
4487 unhold_object(obj);
4488 obj = globallist_next(&marker);
4489 TAILQ_REMOVE(&obj_list, &marker, next);
4490 if (error != 0) {
4491 lock_release(rtld_bind_lock, &bind_lockstate);
4492 lock_release(rtld_phdr_lock, &phdr_lockstate);
4493 return (error);
4494 }
4495 }
4496
4497 if (error == 0) {
4498 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info);
4499 lock_release(rtld_bind_lock, &bind_lockstate);
4500 error = callback(&phdr_info, sizeof(phdr_info), param);
4501 }
4502 lock_release(rtld_phdr_lock, &phdr_lockstate);
4503 return (error);
4504 }
4505
4506 static void *
fill_search_info(const char * dir,size_t dirlen,void * param)4507 fill_search_info(const char *dir, size_t dirlen, void *param)
4508 {
4509 struct fill_search_info_args *arg;
4510
4511 arg = param;
4512
4513 if (arg->request == RTLD_DI_SERINFOSIZE) {
4514 arg->serinfo->dls_cnt++;
4515 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen +
4516 1;
4517 } else {
4518 struct dl_serpath *s_entry;
4519
4520 s_entry = arg->serpath;
4521 s_entry->dls_name = arg->strspace;
4522 s_entry->dls_flags = arg->flags;
4523
4524 strncpy(arg->strspace, dir, dirlen);
4525 arg->strspace[dirlen] = '\0';
4526
4527 arg->strspace += dirlen + 1;
4528 arg->serpath++;
4529 }
4530
4531 return (NULL);
4532 }
4533
4534 static int
do_search_info(const Obj_Entry * obj,int request,struct dl_serinfo * info)4535 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
4536 {
4537 struct dl_serinfo _info;
4538 struct fill_search_info_args args;
4539
4540 args.request = RTLD_DI_SERINFOSIZE;
4541 args.serinfo = &_info;
4542
4543 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
4544 _info.dls_cnt = 0;
4545
4546 path_enumerate(obj->rpath, fill_search_info, NULL, &args);
4547 path_enumerate(ld_library_path, fill_search_info, NULL, &args);
4548 path_enumerate(obj->runpath, fill_search_info, NULL, &args);
4549 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL,
4550 &args);
4551 if (!obj->z_nodeflib)
4552 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
4553 &args);
4554
4555 if (request == RTLD_DI_SERINFOSIZE) {
4556 info->dls_size = _info.dls_size;
4557 info->dls_cnt = _info.dls_cnt;
4558 return (0);
4559 }
4560
4561 if (info->dls_cnt != _info.dls_cnt ||
4562 info->dls_size != _info.dls_size) {
4563 _rtld_error(
4564 "Uninitialized Dl_serinfo struct passed to dlinfo()");
4565 return (-1);
4566 }
4567
4568 args.request = RTLD_DI_SERINFO;
4569 args.serinfo = info;
4570 args.serpath = &info->dls_serpath[0];
4571 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
4572
4573 args.flags = LA_SER_RUNPATH;
4574 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL)
4575 return (-1);
4576
4577 args.flags = LA_SER_LIBPATH;
4578 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) !=
4579 NULL)
4580 return (-1);
4581
4582 args.flags = LA_SER_RUNPATH;
4583 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL)
4584 return (-1);
4585
4586 args.flags = LA_SER_CONFIG;
4587 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL,
4588 &args) != NULL)
4589 return (-1);
4590
4591 args.flags = LA_SER_DEFAULT;
4592 if (!obj->z_nodeflib &&
4593 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
4594 &args) != NULL)
4595 return (-1);
4596 return (0);
4597 }
4598
4599 static int
rtld_dirname(const char * path,char * bname)4600 rtld_dirname(const char *path, char *bname)
4601 {
4602 const char *endp;
4603
4604 /* Empty or NULL string gets treated as "." */
4605 if (path == NULL || *path == '\0') {
4606 bname[0] = '.';
4607 bname[1] = '\0';
4608 return (0);
4609 }
4610
4611 /* Strip trailing slashes */
4612 endp = path + strlen(path) - 1;
4613 while (endp > path && *endp == '/')
4614 endp--;
4615
4616 /* Find the start of the dir */
4617 while (endp > path && *endp != '/')
4618 endp--;
4619
4620 /* Either the dir is "/" or there are no slashes */
4621 if (endp == path) {
4622 bname[0] = *endp == '/' ? '/' : '.';
4623 bname[1] = '\0';
4624 return (0);
4625 } else {
4626 do {
4627 endp--;
4628 } while (endp > path && *endp == '/');
4629 }
4630
4631 if (endp - path + 2 > PATH_MAX) {
4632 _rtld_error("Filename is too long: %s", path);
4633 return (-1);
4634 }
4635
4636 strncpy(bname, path, endp - path + 1);
4637 bname[endp - path + 1] = '\0';
4638 return (0);
4639 }
4640
4641 static int
rtld_dirname_abs(const char * path,char * base)4642 rtld_dirname_abs(const char *path, char *base)
4643 {
4644 char *last;
4645
4646 if (realpath(path, base) == NULL) {
4647 _rtld_error("realpath \"%s\" failed (%s)", path,
4648 rtld_strerror(errno));
4649 return (-1);
4650 }
4651 dbg("%s -> %s", path, base);
4652 last = strrchr(base, '/');
4653 if (last == NULL) {
4654 _rtld_error("non-abs result from realpath \"%s\"", path);
4655 return (-1);
4656 }
4657 if (last != base)
4658 *last = '\0';
4659 return (0);
4660 }
4661
4662 static void
linkmap_add(Obj_Entry * obj)4663 linkmap_add(Obj_Entry *obj)
4664 {
4665 struct link_map *l, *prev;
4666
4667 l = &obj->linkmap;
4668 l->l_name = obj->path;
4669 l->l_base = obj->mapbase;
4670 l->l_ld = obj->dynamic;
4671 l->l_addr = obj->relocbase;
4672
4673 if (r_debug.r_map == NULL) {
4674 r_debug.r_map = l;
4675 return;
4676 }
4677
4678 /*
4679 * Scan to the end of the list, but not past the entry for the
4680 * dynamic linker, which we want to keep at the very end.
4681 */
4682 for (prev = r_debug.r_map;
4683 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
4684 prev = prev->l_next)
4685 ;
4686
4687 /* Link in the new entry. */
4688 l->l_prev = prev;
4689 l->l_next = prev->l_next;
4690 if (l->l_next != NULL)
4691 l->l_next->l_prev = l;
4692 prev->l_next = l;
4693 }
4694
4695 static void
linkmap_delete(Obj_Entry * obj)4696 linkmap_delete(Obj_Entry *obj)
4697 {
4698 struct link_map *l;
4699
4700 l = &obj->linkmap;
4701 if (l->l_prev == NULL) {
4702 if ((r_debug.r_map = l->l_next) != NULL)
4703 l->l_next->l_prev = NULL;
4704 return;
4705 }
4706
4707 if ((l->l_prev->l_next = l->l_next) != NULL)
4708 l->l_next->l_prev = l->l_prev;
4709 }
4710
4711 /*
4712 * Function for the debugger to set a breakpoint on to gain control.
4713 *
4714 * The two parameters allow the debugger to easily find and determine
4715 * what the runtime loader is doing and to whom it is doing it.
4716 *
4717 * When the loadhook trap is hit (r_debug_state, set at program
4718 * initialization), the arguments can be found on the stack:
4719 *
4720 * +8 struct link_map *m
4721 * +4 struct r_debug *rd
4722 * +0 RetAddr
4723 */
4724 void
r_debug_state(struct r_debug * rd __unused,struct link_map * m __unused)4725 r_debug_state(struct r_debug *rd __unused, struct link_map *m __unused)
4726 {
4727 /*
4728 * The following is a hack to force the compiler to emit calls to
4729 * this function, even when optimizing. If the function is empty,
4730 * the compiler is not obliged to emit any code for calls to it,
4731 * even when marked __noinline. However, gdb depends on those
4732 * calls being made.
4733 */
4734 __compiler_membar();
4735 }
4736
4737 /*
4738 * A function called after init routines have completed. This can be used to
4739 * break before a program's entry routine is called, and can be used when
4740 * main is not available in the symbol table.
4741 */
4742 void
_r_debug_postinit(struct link_map * m __unused)4743 _r_debug_postinit(struct link_map *m __unused)
4744 {
4745 /* See r_debug_state(). */
4746 __compiler_membar();
4747 }
4748
4749 static void
release_object(Obj_Entry * obj)4750 release_object(Obj_Entry *obj)
4751 {
4752 if (obj->holdcount > 0) {
4753 obj->unholdfree = true;
4754 return;
4755 }
4756 munmap(obj->mapbase, obj->mapsize);
4757 linkmap_delete(obj);
4758 obj_free(obj);
4759 }
4760
4761 /*
4762 * Get address of the pointer variable in the main program.
4763 * Prefer non-weak symbol over the weak one.
4764 */
4765 static const void **
get_program_var_addr(const char * name,RtldLockState * lockstate)4766 get_program_var_addr(const char *name, RtldLockState *lockstate)
4767 {
4768 SymLook req;
4769 DoneList donelist;
4770 const void **res;
4771
4772 symlook_init(&req, name);
4773 req.lockstate = lockstate;
4774 donelist_init(&donelist, NULL);
4775 if (symlook_global(&req, &donelist) != 0)
4776 return (NULL);
4777 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
4778 res = (const void **)make_function_pointer(req.sym_out,
4779 req.defobj_out);
4780 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
4781 res = (const void **)rtld_resolve_ifunc(req.defobj_out,
4782 req.sym_out);
4783 else
4784 res = (const void **)(req.defobj_out->relocbase +
4785 req.sym_out->st_value);
4786 donelist_free(&donelist);
4787 return (res);
4788 }
4789
4790 /*
4791 * Set a pointer variable in the main program to the given value. This
4792 * is used to set key variables such as "environ" before any of the
4793 * init functions are called.
4794 */
4795 static void
set_program_var(const char * name,const void * value)4796 set_program_var(const char *name, const void *value)
4797 {
4798 const void **addr;
4799
4800 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
4801 dbg("\"%s\": *%p <-- %p", name, addr, value);
4802 *addr = value;
4803 }
4804 }
4805
4806 /*
4807 * Search the global objects, including dependencies and main object,
4808 * for the given symbol.
4809 */
4810 static int
symlook_global(SymLook * req,DoneList * donelist)4811 symlook_global(SymLook *req, DoneList *donelist)
4812 {
4813 SymLook req1;
4814 const Objlist_Entry *elm;
4815 int res;
4816
4817 symlook_init_from_req(&req1, req);
4818
4819 /* Search all objects loaded at program start up. */
4820 if (req->defobj_out == NULL || (ld_dynamic_weak &&
4821 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK)) {
4822 res = symlook_list(&req1, &list_main, donelist);
4823 if (res == 0 && (!ld_dynamic_weak || req->defobj_out == NULL ||
4824 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4825 req->sym_out = req1.sym_out;
4826 req->defobj_out = req1.defobj_out;
4827 assert(req->defobj_out != NULL);
4828 }
4829 }
4830
4831 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
4832 STAILQ_FOREACH(elm, &list_global, link) {
4833 if (req->defobj_out != NULL && (!ld_dynamic_weak ||
4834 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK))
4835 break;
4836 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
4837 if (res == 0 && (req->defobj_out == NULL ||
4838 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4839 req->sym_out = req1.sym_out;
4840 req->defobj_out = req1.defobj_out;
4841 assert(req->defobj_out != NULL);
4842 }
4843 }
4844
4845 return (req->sym_out != NULL ? 0 : ESRCH);
4846 }
4847
4848 /*
4849 * Given a symbol name in a referencing object, find the corresponding
4850 * definition of the symbol. Returns a pointer to the symbol, or NULL if
4851 * no definition was found. Returns a pointer to the Obj_Entry of the
4852 * defining object via the reference parameter DEFOBJ_OUT.
4853 */
4854 static int
symlook_default(SymLook * req,const Obj_Entry * refobj)4855 symlook_default(SymLook *req, const Obj_Entry *refobj)
4856 {
4857 DoneList donelist;
4858 const Objlist_Entry *elm;
4859 SymLook req1;
4860 int res;
4861
4862 donelist_init(&donelist, req);
4863 symlook_init_from_req(&req1, req);
4864
4865 /*
4866 * Look first in the referencing object if linked symbolically,
4867 * and similarly handle protected symbols.
4868 */
4869 res = symlook_obj(&req1, refobj);
4870 if (res == 0 && (refobj->symbolic ||
4871 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED ||
4872 refobj->deepbind)) {
4873 req->sym_out = req1.sym_out;
4874 req->defobj_out = req1.defobj_out;
4875 assert(req->defobj_out != NULL);
4876 }
4877 if (refobj->symbolic || req->defobj_out != NULL || refobj->deepbind)
4878 donelist_check(&donelist, refobj);
4879
4880 if (!refobj->deepbind)
4881 symlook_global(req, &donelist);
4882
4883 /* Search all dlopened DAGs containing the referencing object. */
4884 STAILQ_FOREACH(elm, &refobj->dldags, link) {
4885 if (req->sym_out != NULL && (!ld_dynamic_weak ||
4886 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK))
4887 break;
4888 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
4889 if (res == 0 && (req->sym_out == NULL ||
4890 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4891 req->sym_out = req1.sym_out;
4892 req->defobj_out = req1.defobj_out;
4893 assert(req->defobj_out != NULL);
4894 }
4895 }
4896
4897 if (refobj->deepbind)
4898 symlook_global(req, &donelist);
4899
4900 /*
4901 * Search the dynamic linker itself, and possibly resolve the
4902 * symbol from there. This is how the application links to
4903 * dynamic linker services such as dlopen.
4904 */
4905 if (req->sym_out == NULL ||
4906 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
4907 res = symlook_obj(&req1, &obj_rtld);
4908 if (res == 0) {
4909 req->sym_out = req1.sym_out;
4910 req->defobj_out = req1.defobj_out;
4911 assert(req->defobj_out != NULL);
4912 }
4913 }
4914
4915 donelist_free(&donelist);
4916 return (req->sym_out != NULL ? 0 : ESRCH);
4917 }
4918
4919 static int
symlook_list(SymLook * req,const Objlist * objlist,DoneList * dlp)4920 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
4921 {
4922 const Elf_Sym *def;
4923 const Obj_Entry *defobj;
4924 const Objlist_Entry *elm;
4925 SymLook req1;
4926 int res;
4927
4928 def = NULL;
4929 defobj = NULL;
4930 STAILQ_FOREACH(elm, objlist, link) {
4931 if (donelist_check(dlp, elm->obj))
4932 continue;
4933 symlook_init_from_req(&req1, req);
4934 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
4935 if (def == NULL || (ld_dynamic_weak &&
4936 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4937 def = req1.sym_out;
4938 defobj = req1.defobj_out;
4939 if (!ld_dynamic_weak ||
4940 ELF_ST_BIND(def->st_info) != STB_WEAK)
4941 break;
4942 }
4943 }
4944 }
4945 if (def != NULL) {
4946 req->sym_out = def;
4947 req->defobj_out = defobj;
4948 return (0);
4949 }
4950 return (ESRCH);
4951 }
4952
4953 /*
4954 * Search the chain of DAGS cointed to by the given Needed_Entry
4955 * for a symbol of the given name. Each DAG is scanned completely
4956 * before advancing to the next one. Returns a pointer to the symbol,
4957 * or NULL if no definition was found.
4958 */
4959 static int
symlook_needed(SymLook * req,const Needed_Entry * needed,DoneList * dlp)4960 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
4961 {
4962 const Elf_Sym *def;
4963 const Needed_Entry *n;
4964 const Obj_Entry *defobj;
4965 SymLook req1;
4966 int res;
4967
4968 def = NULL;
4969 defobj = NULL;
4970 symlook_init_from_req(&req1, req);
4971 for (n = needed; n != NULL; n = n->next) {
4972 if (n->obj == NULL || (res = symlook_list(&req1,
4973 &n->obj->dagmembers, dlp)) != 0)
4974 continue;
4975 if (def == NULL || (ld_dynamic_weak &&
4976 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4977 def = req1.sym_out;
4978 defobj = req1.defobj_out;
4979 if (!ld_dynamic_weak ||
4980 ELF_ST_BIND(def->st_info) != STB_WEAK)
4981 break;
4982 }
4983 }
4984 if (def != NULL) {
4985 req->sym_out = def;
4986 req->defobj_out = defobj;
4987 return (0);
4988 }
4989 return (ESRCH);
4990 }
4991
4992 static int
symlook_obj_load_filtees(SymLook * req,SymLook * req1,const Obj_Entry * obj,Needed_Entry * needed)4993 symlook_obj_load_filtees(SymLook *req, SymLook *req1, const Obj_Entry *obj,
4994 Needed_Entry *needed)
4995 {
4996 DoneList donelist;
4997 int flags, res;
4998
4999 flags = (req->flags & SYMLOOK_EARLY) != 0 ? RTLD_LO_EARLY : 0;
5000 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
5001 donelist_init(&donelist, NULL);
5002 symlook_init_from_req(req1, req);
5003 res = symlook_needed(req1, needed, &donelist);
5004 donelist_free(&donelist);
5005 return (res);
5006 }
5007
5008 /*
5009 * Search the symbol table of a single shared object for a symbol of
5010 * the given name and version, if requested. Returns a pointer to the
5011 * symbol, or NULL if no definition was found. If the object is
5012 * filter, return filtered symbol from filtee.
5013 *
5014 * The symbol's hash value is passed in for efficiency reasons; that
5015 * eliminates many recomputations of the hash value.
5016 */
5017 int
symlook_obj(SymLook * req,const Obj_Entry * obj)5018 symlook_obj(SymLook *req, const Obj_Entry *obj)
5019 {
5020 SymLook req1;
5021 int res, mres;
5022
5023 /*
5024 * If there is at least one valid hash at this point, we prefer to
5025 * use the faster GNU version if available.
5026 */
5027 if (obj->valid_hash_gnu)
5028 mres = symlook_obj1_gnu(req, obj);
5029 else if (obj->valid_hash_sysv)
5030 mres = symlook_obj1_sysv(req, obj);
5031 else
5032 return (EINVAL);
5033
5034 if (mres == 0) {
5035 if (obj->needed_filtees != NULL) {
5036 res = symlook_obj_load_filtees(req, &req1, obj,
5037 obj->needed_filtees);
5038 if (res == 0) {
5039 req->sym_out = req1.sym_out;
5040 req->defobj_out = req1.defobj_out;
5041 }
5042 return (res);
5043 }
5044 if (obj->needed_aux_filtees != NULL) {
5045 res = symlook_obj_load_filtees(req, &req1, obj,
5046 obj->needed_aux_filtees);
5047 if (res == 0) {
5048 req->sym_out = req1.sym_out;
5049 req->defobj_out = req1.defobj_out;
5050 return (res);
5051 }
5052 }
5053 }
5054 return (mres);
5055 }
5056
5057 /* Symbol match routine common to both hash functions */
5058 static bool
matched_symbol(SymLook * req,const Obj_Entry * obj,Sym_Match_Result * result,const unsigned long symnum)5059 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
5060 const unsigned long symnum)
5061 {
5062 Elf_Versym verndx;
5063 const Elf_Sym *symp;
5064 const char *strp;
5065
5066 symp = obj->symtab + symnum;
5067 strp = obj->strtab + symp->st_name;
5068
5069 switch (ELF_ST_TYPE(symp->st_info)) {
5070 case STT_FUNC:
5071 case STT_NOTYPE:
5072 case STT_OBJECT:
5073 case STT_COMMON:
5074 case STT_GNU_IFUNC:
5075 if (symp->st_value == 0)
5076 return (false);
5077 /* fallthrough */
5078 case STT_TLS:
5079 if (symp->st_shndx != SHN_UNDEF)
5080 break;
5081 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
5082 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
5083 break;
5084 /* fallthrough */
5085 default:
5086 return (false);
5087 }
5088 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
5089 return (false);
5090
5091 if (req->ventry == NULL) {
5092 if (obj->versyms != NULL) {
5093 verndx = VER_NDX(obj->versyms[symnum]);
5094 if (verndx > obj->vernum) {
5095 _rtld_error(
5096 "%s: symbol %s references wrong version %d",
5097 obj->path, obj->strtab + symnum, verndx);
5098 return (false);
5099 }
5100 /*
5101 * If we are not called from dlsym (i.e. this
5102 * is a normal relocation from unversioned
5103 * binary), accept the symbol immediately if
5104 * it happens to have first version after this
5105 * shared object became versioned. Otherwise,
5106 * if symbol is versioned and not hidden,
5107 * remember it. If it is the only symbol with
5108 * this name exported by the shared object, it
5109 * will be returned as a match by the calling
5110 * function. If symbol is global (verndx < 2)
5111 * accept it unconditionally.
5112 */
5113 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
5114 verndx == VER_NDX_GIVEN) {
5115 result->sym_out = symp;
5116 return (true);
5117 } else if (verndx >= VER_NDX_GIVEN) {
5118 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) ==
5119 0) {
5120 if (result->vsymp == NULL)
5121 result->vsymp = symp;
5122 result->vcount++;
5123 }
5124 return (false);
5125 }
5126 }
5127 result->sym_out = symp;
5128 return (true);
5129 }
5130 if (obj->versyms == NULL) {
5131 if (object_match_name(obj, req->ventry->name)) {
5132 _rtld_error(
5133 "%s: object %s should provide version %s for symbol %s",
5134 obj_rtld.path, obj->path, req->ventry->name,
5135 obj->strtab + symnum);
5136 return (false);
5137 }
5138 } else {
5139 verndx = VER_NDX(obj->versyms[symnum]);
5140 if (verndx > obj->vernum) {
5141 _rtld_error("%s: symbol %s references wrong version %d",
5142 obj->path, obj->strtab + symnum, verndx);
5143 return (false);
5144 }
5145 if (obj->vertab[verndx].hash != req->ventry->hash ||
5146 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
5147 /*
5148 * Version does not match. Look if this is a
5149 * global symbol and if it is not hidden. If
5150 * global symbol (verndx < 2) is available,
5151 * use it. Do not return symbol if we are
5152 * called by dlvsym, because dlvsym looks for
5153 * a specific version and default one is not
5154 * what dlvsym wants.
5155 */
5156 if ((req->flags & SYMLOOK_DLSYM) ||
5157 (verndx >= VER_NDX_GIVEN) ||
5158 (obj->versyms[symnum] & VER_NDX_HIDDEN))
5159 return (false);
5160 }
5161 }
5162 result->sym_out = symp;
5163 return (true);
5164 }
5165
5166 /*
5167 * Search for symbol using SysV hash function.
5168 * obj->buckets is known not to be NULL at this point; the test for this was
5169 * performed with the obj->valid_hash_sysv assignment.
5170 */
5171 static int
symlook_obj1_sysv(SymLook * req,const Obj_Entry * obj)5172 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
5173 {
5174 unsigned long symnum;
5175 Sym_Match_Result matchres;
5176
5177 matchres.sym_out = NULL;
5178 matchres.vsymp = NULL;
5179 matchres.vcount = 0;
5180
5181 for (symnum = obj->buckets[req->hash % obj->nbuckets];
5182 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
5183 if (symnum >= obj->nchains)
5184 return (ESRCH); /* Bad object */
5185
5186 if (matched_symbol(req, obj, &matchres, symnum)) {
5187 req->sym_out = matchres.sym_out;
5188 req->defobj_out = obj;
5189 return (0);
5190 }
5191 }
5192 if (matchres.vcount == 1) {
5193 req->sym_out = matchres.vsymp;
5194 req->defobj_out = obj;
5195 return (0);
5196 }
5197 return (ESRCH);
5198 }
5199
5200 /* Search for symbol using GNU hash function */
5201 static int
symlook_obj1_gnu(SymLook * req,const Obj_Entry * obj)5202 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
5203 {
5204 Elf_Addr bloom_word;
5205 const Elf32_Word *hashval;
5206 Elf32_Word bucket;
5207 Sym_Match_Result matchres;
5208 unsigned int h1, h2;
5209 unsigned long symnum;
5210
5211 matchres.sym_out = NULL;
5212 matchres.vsymp = NULL;
5213 matchres.vcount = 0;
5214
5215 /* Pick right bitmask word from Bloom filter array */
5216 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
5217 obj->maskwords_bm_gnu];
5218
5219 /* Calculate modulus word size of gnu hash and its derivative */
5220 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
5221 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
5222
5223 /* Filter out the "definitely not in set" queries */
5224 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
5225 return (ESRCH);
5226
5227 /* Locate hash chain and corresponding value element*/
5228 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
5229 if (bucket == 0)
5230 return (ESRCH);
5231 hashval = &obj->chain_zero_gnu[bucket];
5232 do {
5233 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
5234 symnum = hashval - obj->chain_zero_gnu;
5235 if (matched_symbol(req, obj, &matchres, symnum)) {
5236 req->sym_out = matchres.sym_out;
5237 req->defobj_out = obj;
5238 return (0);
5239 }
5240 }
5241 } while ((*hashval++ & 1) == 0);
5242 if (matchres.vcount == 1) {
5243 req->sym_out = matchres.vsymp;
5244 req->defobj_out = obj;
5245 return (0);
5246 }
5247 return (ESRCH);
5248 }
5249
5250 static void
trace_calc_fmts(const char ** main_local,const char ** fmt1,const char ** fmt2)5251 trace_calc_fmts(const char **main_local, const char **fmt1, const char **fmt2)
5252 {
5253 *main_local = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_PROGNAME);
5254 if (*main_local == NULL)
5255 *main_local = "";
5256
5257 *fmt1 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT1);
5258 if (*fmt1 == NULL)
5259 *fmt1 = "\t%o => %p (%x)\n";
5260
5261 *fmt2 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT2);
5262 if (*fmt2 == NULL)
5263 *fmt2 = "\t%o (%x)\n";
5264 }
5265
5266 static void
trace_print_obj(Obj_Entry * obj,const char * name,const char * path,const char * main_local,const char * fmt1,const char * fmt2)5267 trace_print_obj(Obj_Entry *obj, const char *name, const char *path,
5268 const char *main_local, const char *fmt1, const char *fmt2)
5269 {
5270 const char *fmt;
5271 int c;
5272
5273 if (fmt1 == NULL)
5274 fmt = fmt2;
5275 else
5276 /* XXX bogus */
5277 fmt = strncmp(name, "lib", 3) == 0 ? fmt1 : fmt2;
5278
5279 while ((c = *fmt++) != '\0') {
5280 switch (c) {
5281 default:
5282 rtld_putchar(c);
5283 continue;
5284 case '\\':
5285 switch (c = *fmt) {
5286 case '\0':
5287 continue;
5288 case 'n':
5289 rtld_putchar('\n');
5290 break;
5291 case 't':
5292 rtld_putchar('\t');
5293 break;
5294 }
5295 break;
5296 case '%':
5297 switch (c = *fmt) {
5298 case '\0':
5299 continue;
5300 case '%':
5301 default:
5302 rtld_putchar(c);
5303 break;
5304 case 'A':
5305 rtld_putstr(main_local);
5306 break;
5307 case 'a':
5308 rtld_putstr(obj_main->path);
5309 break;
5310 case 'o':
5311 rtld_putstr(name);
5312 break;
5313 case 'p':
5314 rtld_putstr(path);
5315 break;
5316 case 'x':
5317 rtld_printf("%p",
5318 obj != NULL ? obj->mapbase : NULL);
5319 break;
5320 }
5321 break;
5322 }
5323 ++fmt;
5324 }
5325 }
5326
5327 static void
trace_loaded_objects(Obj_Entry * obj,bool show_preload)5328 trace_loaded_objects(Obj_Entry *obj, bool show_preload)
5329 {
5330 const char *fmt1, *fmt2, *main_local;
5331 const char *name, *path;
5332 bool first_spurious, list_containers;
5333
5334 trace_calc_fmts(&main_local, &fmt1, &fmt2);
5335 list_containers = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_ALL) != NULL;
5336
5337 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
5338 Needed_Entry *needed;
5339
5340 if (obj->marker)
5341 continue;
5342 if (list_containers && obj->needed != NULL)
5343 rtld_printf("%s:\n", obj->path);
5344 for (needed = obj->needed; needed; needed = needed->next) {
5345 if (needed->obj != NULL) {
5346 if (needed->obj->traced && !list_containers)
5347 continue;
5348 needed->obj->traced = true;
5349 path = needed->obj->path;
5350 } else
5351 path = "not found";
5352
5353 name = obj->strtab + needed->name;
5354 trace_print_obj(needed->obj, name, path, main_local,
5355 fmt1, fmt2);
5356 }
5357 }
5358
5359 if (show_preload) {
5360 if (ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT2) == NULL)
5361 fmt2 = "\t%p (%x)\n";
5362 first_spurious = true;
5363
5364 TAILQ_FOREACH(obj, &obj_list, next) {
5365 if (obj->marker || obj == obj_main || obj->traced)
5366 continue;
5367
5368 if (list_containers && first_spurious) {
5369 rtld_printf("[preloaded]\n");
5370 first_spurious = false;
5371 }
5372
5373 Name_Entry *fname = STAILQ_FIRST(&obj->names);
5374 name = fname == NULL ? "<unknown>" : fname->name;
5375 trace_print_obj(obj, name, obj->path, main_local, NULL,
5376 fmt2);
5377 }
5378 }
5379 }
5380
5381 /*
5382 * Unload a dlopened object and its dependencies from memory and from
5383 * our data structures. It is assumed that the DAG rooted in the
5384 * object has already been unreferenced, and that the object has a
5385 * reference count of 0.
5386 */
5387 static void
unload_object(Obj_Entry * root,RtldLockState * lockstate)5388 unload_object(Obj_Entry *root, RtldLockState *lockstate)
5389 {
5390 Obj_Entry marker, *obj, *next;
5391
5392 assert(root->refcount == 0);
5393
5394 /*
5395 * Pass over the DAG removing unreferenced objects from
5396 * appropriate lists.
5397 */
5398 unlink_object(root);
5399
5400 /* Unmap all objects that are no longer referenced. */
5401 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) {
5402 next = TAILQ_NEXT(obj, next);
5403 if (obj->marker || obj->refcount != 0)
5404 continue;
5405 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize,
5406 0, obj->path);
5407 dbg("unloading \"%s\"", obj->path);
5408 /*
5409 * Unlink the object now to prevent new references from
5410 * being acquired while the bind lock is dropped in
5411 * recursive dlclose() invocations.
5412 */
5413 TAILQ_REMOVE(&obj_list, obj, next);
5414 obj_count--;
5415
5416 if (obj->filtees_loaded) {
5417 if (next != NULL) {
5418 init_marker(&marker);
5419 TAILQ_INSERT_BEFORE(next, &marker, next);
5420 unload_filtees(obj, lockstate);
5421 next = TAILQ_NEXT(&marker, next);
5422 TAILQ_REMOVE(&obj_list, &marker, next);
5423 } else
5424 unload_filtees(obj, lockstate);
5425 }
5426 release_object(obj);
5427 }
5428 }
5429
5430 static void
unlink_object(Obj_Entry * root)5431 unlink_object(Obj_Entry *root)
5432 {
5433 Objlist_Entry *elm;
5434
5435 if (root->refcount == 0) {
5436 /* Remove the object from the RTLD_GLOBAL list. */
5437 objlist_remove(&list_global, root);
5438
5439 /* Remove the object from all objects' DAG lists. */
5440 STAILQ_FOREACH(elm, &root->dagmembers, link) {
5441 objlist_remove(&elm->obj->dldags, root);
5442 if (elm->obj != root)
5443 unlink_object(elm->obj);
5444 }
5445 }
5446 }
5447
5448 static void
ref_dag(Obj_Entry * root)5449 ref_dag(Obj_Entry *root)
5450 {
5451 Objlist_Entry *elm;
5452
5453 assert(root->dag_inited);
5454 STAILQ_FOREACH(elm, &root->dagmembers, link)
5455 elm->obj->refcount++;
5456 }
5457
5458 static void
unref_dag(Obj_Entry * root)5459 unref_dag(Obj_Entry *root)
5460 {
5461 Objlist_Entry *elm;
5462
5463 assert(root->dag_inited);
5464 STAILQ_FOREACH(elm, &root->dagmembers, link)
5465 elm->obj->refcount--;
5466 }
5467
5468 /*
5469 * Common code for MD __tls_get_addr().
5470 *
5471 * The tcb->tcb_dtv data structure is thread-local. The reason that
5472 * the function needs to take the rtld_bind_lock exclusive (as opposed
5473 * to only shared, to safely access obj_list in allocate_module_tls())
5474 * is to protect the rtld_malloc data.
5475 */
5476 static void *
tls_get_addr_slow(struct tcb * tcb,int index,size_t offset,bool locked)5477 tls_get_addr_slow(struct tcb *tcb, int index, size_t offset, bool locked)
5478 {
5479 struct dtv *newdtv, *dtv;
5480 RtldLockState lockstate;
5481 int to_copy;
5482
5483 dtv = tcb->tcb_dtv;
5484 /* Check dtv generation in case new modules have arrived */
5485 if (dtv->dtv_gen != tls_dtv_generation) {
5486 if (!locked)
5487 wlock_acquire(rtld_bind_lock, &lockstate);
5488 newdtv = xcalloc(1, sizeof(struct dtv) + tls_max_index *
5489 sizeof(struct dtv_slot));
5490 to_copy = dtv->dtv_size;
5491 if (to_copy > tls_max_index)
5492 to_copy = tls_max_index;
5493 memcpy(newdtv->dtv_slots, dtv->dtv_slots, to_copy *
5494 sizeof(struct dtv_slot));
5495 newdtv->dtv_gen = tls_dtv_generation;
5496 newdtv->dtv_size = tls_max_index;
5497 free(dtv);
5498 if (!locked)
5499 lock_release(rtld_bind_lock, &lockstate);
5500 dtv = tcb->tcb_dtv = newdtv;
5501 }
5502
5503 /* Dynamically allocate module TLS if necessary */
5504 if (dtv->dtv_slots[index - 1].dtvs_tls == 0) {
5505 /* Signal safe, wlock will block out signals. */
5506 if (!locked)
5507 wlock_acquire(rtld_bind_lock, &lockstate);
5508 if (!dtv->dtv_slots[index - 1].dtvs_tls)
5509 dtv->dtv_slots[index - 1].dtvs_tls =
5510 allocate_module_tls(tcb, index);
5511 if (!locked)
5512 lock_release(rtld_bind_lock, &lockstate);
5513 }
5514 return (dtv->dtv_slots[index - 1].dtvs_tls + offset);
5515 }
5516
5517 void *
tls_get_addr_common(struct tcb * tcb,int index,size_t offset)5518 tls_get_addr_common(struct tcb *tcb, int index, size_t offset)
5519 {
5520 struct dtv *dtv;
5521
5522 dtv = tcb->tcb_dtv;
5523 /* Check dtv generation in case new modules have arrived */
5524 if (__predict_true(dtv->dtv_gen == tls_dtv_generation &&
5525 dtv->dtv_slots[index - 1].dtvs_tls != 0))
5526 return (dtv->dtv_slots[index - 1].dtvs_tls + offset);
5527 return (tls_get_addr_slow(tcb, index, offset, false));
5528 }
5529
5530 static struct tcb *
tcb_from_tcb_list_entry(struct tcb_list_entry * tcbelm)5531 tcb_from_tcb_list_entry(struct tcb_list_entry *tcbelm)
5532 {
5533 #ifdef TLS_VARIANT_I
5534 return ((struct tcb *)((char *)tcbelm - tcb_list_entry_offset));
5535 #else
5536 return ((struct tcb *)((char *)tcbelm + tcb_list_entry_offset));
5537 #endif
5538 }
5539
5540 static struct tcb_list_entry *
tcb_list_entry_from_tcb(struct tcb * tcb)5541 tcb_list_entry_from_tcb(struct tcb *tcb)
5542 {
5543 #ifdef TLS_VARIANT_I
5544 return ((struct tcb_list_entry *)((char *)tcb + tcb_list_entry_offset));
5545 #else
5546 return ((struct tcb_list_entry *)((char *)tcb - tcb_list_entry_offset));
5547 #endif
5548 }
5549
5550 static void
tcb_list_insert(struct tcb * tcb)5551 tcb_list_insert(struct tcb *tcb)
5552 {
5553 struct tcb_list_entry *tcbelm;
5554
5555 tcbelm = tcb_list_entry_from_tcb(tcb);
5556 TAILQ_INSERT_TAIL(&tcb_list, tcbelm, next);
5557 }
5558
5559 static void
tcb_list_remove(struct tcb * tcb)5560 tcb_list_remove(struct tcb *tcb)
5561 {
5562 struct tcb_list_entry *tcbelm;
5563
5564 tcbelm = tcb_list_entry_from_tcb(tcb);
5565 TAILQ_REMOVE(&tcb_list, tcbelm, next);
5566 }
5567
5568 #ifdef TLS_VARIANT_I
5569
5570 /*
5571 * Return pointer to allocated TLS block
5572 */
5573 static void *
get_tls_block_ptr(void * tcb,size_t tcbsize)5574 get_tls_block_ptr(void *tcb, size_t tcbsize)
5575 {
5576 size_t extra_size, post_size, pre_size, tls_block_size;
5577 size_t tls_init_align;
5578
5579 tls_init_align = MAX(obj_main->tlsalign, 1);
5580
5581 /* Compute fragments sizes. */
5582 extra_size = tcbsize - TLS_TCB_SIZE;
5583 post_size = calculate_tls_post_size(tls_init_align);
5584 tls_block_size = tcbsize + post_size;
5585 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size;
5586
5587 return ((char *)tcb - pre_size - extra_size);
5588 }
5589
5590 /*
5591 * Allocate Static TLS using the Variant I method.
5592 *
5593 * For details on the layout, see lib/libc/gen/tls.c.
5594 *
5595 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as
5596 * it is based on tls_last_offset, and TLS offsets here are really TCB
5597 * offsets, whereas libc's tls_static_space is just the executable's static
5598 * TLS segment.
5599 *
5600 * NB: This differs from NetBSD's ld.elf_so, where TLS offsets are relative to
5601 * the end of the TCB.
5602 */
5603 void *
allocate_tls(Obj_Entry * objs,void * oldtcb,size_t tcbsize,size_t tcbalign)5604 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
5605 {
5606 Obj_Entry *obj;
5607 char *tls_block;
5608 struct dtv *dtv;
5609 struct tcb *tcb;
5610 char *addr;
5611 size_t i;
5612 size_t extra_size, maxalign, post_size, pre_size, tls_block_size;
5613 size_t tls_init_align, tls_init_offset, tls_bss_offset;
5614
5615 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
5616 return (oldtcb);
5617
5618 assert(tcbsize >= TLS_TCB_SIZE);
5619 maxalign = MAX(tcbalign, tls_static_max_align);
5620 tls_init_align = MAX(obj_main->tlsalign, 1);
5621
5622 /* Compute fragments sizes. */
5623 extra_size = tcbsize - TLS_TCB_SIZE;
5624 post_size = calculate_tls_post_size(tls_init_align);
5625 tls_block_size = tcbsize + post_size;
5626 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size;
5627 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE -
5628 post_size;
5629
5630 /* Allocate whole TLS block */
5631 tls_block = xmalloc_aligned(tls_block_size, maxalign, 0);
5632 tcb = (struct tcb *)(tls_block + pre_size + extra_size);
5633
5634 if (oldtcb != NULL) {
5635 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize),
5636 tls_static_space);
5637 free(get_tls_block_ptr(oldtcb, tcbsize));
5638
5639 /* Adjust the DTV. */
5640 dtv = tcb->tcb_dtv;
5641 for (i = 0; i < dtv->dtv_size; i++) {
5642 if ((uintptr_t)dtv->dtv_slots[i].dtvs_tls >=
5643 (uintptr_t)oldtcb &&
5644 (uintptr_t)dtv->dtv_slots[i].dtvs_tls <
5645 (uintptr_t)oldtcb + tls_static_space) {
5646 dtv->dtv_slots[i].dtvs_tls = (char *)tcb +
5647 (dtv->dtv_slots[i].dtvs_tls -
5648 (char *)oldtcb);
5649 }
5650 }
5651 } else {
5652 dtv = xcalloc(1, sizeof(struct dtv) + tls_max_index *
5653 sizeof(struct dtv_slot));
5654 tcb->tcb_dtv = dtv;
5655 dtv->dtv_gen = tls_dtv_generation;
5656 dtv->dtv_size = tls_max_index;
5657
5658 for (obj = globallist_curr(objs); obj != NULL;
5659 obj = globallist_next(obj)) {
5660 if (obj->tlsoffset == 0)
5661 continue;
5662 tls_init_offset = obj->tlspoffset & (obj->tlsalign - 1);
5663 addr = (char *)tcb + obj->tlsoffset;
5664 if (tls_init_offset > 0)
5665 memset(addr, 0, tls_init_offset);
5666 if (obj->tlsinitsize > 0) {
5667 memcpy(addr + tls_init_offset, obj->tlsinit,
5668 obj->tlsinitsize);
5669 }
5670 if (obj->tlssize > obj->tlsinitsize) {
5671 tls_bss_offset = tls_init_offset +
5672 obj->tlsinitsize;
5673 memset(addr + tls_bss_offset, 0,
5674 obj->tlssize - tls_bss_offset);
5675 }
5676 dtv->dtv_slots[obj->tlsindex - 1].dtvs_tls = addr;
5677 }
5678 }
5679
5680 tcb_list_insert(tcb);
5681 return (tcb);
5682 }
5683
5684 void
free_tls(void * tcb,size_t tcbsize,size_t tcbalign __unused)5685 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused)
5686 {
5687 struct dtv *dtv;
5688 uintptr_t tlsstart, tlsend;
5689 size_t post_size;
5690 size_t i, tls_init_align __unused;
5691
5692 tcb_list_remove(tcb);
5693
5694 assert(tcbsize >= TLS_TCB_SIZE);
5695 tls_init_align = MAX(obj_main->tlsalign, 1);
5696
5697 /* Compute fragments sizes. */
5698 post_size = calculate_tls_post_size(tls_init_align);
5699
5700 tlsstart = (uintptr_t)tcb + TLS_TCB_SIZE + post_size;
5701 tlsend = (uintptr_t)tcb + tls_static_space;
5702
5703 dtv = ((struct tcb *)tcb)->tcb_dtv;
5704 for (i = 0; i < dtv->dtv_size; i++) {
5705 if (dtv->dtv_slots[i].dtvs_tls != NULL &&
5706 ((uintptr_t)dtv->dtv_slots[i].dtvs_tls < tlsstart ||
5707 (uintptr_t)dtv->dtv_slots[i].dtvs_tls >= tlsend)) {
5708 free(dtv->dtv_slots[i].dtvs_tls);
5709 }
5710 }
5711 free(dtv);
5712 free(get_tls_block_ptr(tcb, tcbsize));
5713 }
5714
5715 #endif /* TLS_VARIANT_I */
5716
5717 #ifdef TLS_VARIANT_II
5718
5719 /*
5720 * Allocate Static TLS using the Variant II method.
5721 */
5722 void *
allocate_tls(Obj_Entry * objs,void * oldtcb,size_t tcbsize,size_t tcbalign)5723 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
5724 {
5725 Obj_Entry *obj;
5726 size_t size, ralign;
5727 char *tls_block;
5728 struct dtv *dtv, *olddtv;
5729 struct tcb *tcb;
5730 char *addr;
5731 size_t i;
5732
5733 ralign = tcbalign;
5734 if (tls_static_max_align > ralign)
5735 ralign = tls_static_max_align;
5736 size = roundup(tls_static_space, ralign) + roundup(tcbsize, ralign);
5737
5738 assert(tcbsize >= 2 * sizeof(uintptr_t));
5739 tls_block = xmalloc_aligned(size, ralign, 0 /* XXX */);
5740 dtv = xcalloc(1, sizeof(struct dtv) + tls_max_index *
5741 sizeof(struct dtv_slot));
5742
5743 tcb = (struct tcb *)(tls_block + roundup(tls_static_space, ralign));
5744 tcb->tcb_self = tcb;
5745 tcb->tcb_dtv = dtv;
5746
5747 dtv->dtv_gen = tls_dtv_generation;
5748 dtv->dtv_size = tls_max_index;
5749
5750 if (oldtcb != NULL) {
5751 /*
5752 * Copy the static TLS block over whole.
5753 */
5754 memcpy((char *)tcb - tls_static_space,
5755 (const char *)oldtcb - tls_static_space,
5756 tls_static_space);
5757
5758 /*
5759 * If any dynamic TLS blocks have been created tls_get_addr(),
5760 * move them over.
5761 */
5762 olddtv = ((struct tcb *)oldtcb)->tcb_dtv;
5763 for (i = 0; i < olddtv->dtv_size; i++) {
5764 if ((uintptr_t)olddtv->dtv_slots[i].dtvs_tls <
5765 (uintptr_t)oldtcb - size ||
5766 (uintptr_t)olddtv->dtv_slots[i].dtvs_tls >
5767 (uintptr_t)oldtcb) {
5768 dtv->dtv_slots[i].dtvs_tls =
5769 olddtv->dtv_slots[i].dtvs_tls;
5770 olddtv->dtv_slots[i].dtvs_tls = NULL;
5771 }
5772 }
5773
5774 /*
5775 * We assume that this block was the one we created with
5776 * allocate_initial_tls().
5777 */
5778 free_tls(oldtcb, 2 * sizeof(uintptr_t), sizeof(uintptr_t));
5779 } else {
5780 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
5781 if (obj->marker || obj->tlsoffset == 0)
5782 continue;
5783 addr = (char *)tcb - obj->tlsoffset;
5784 memset(addr + obj->tlsinitsize, 0, obj->tlssize -
5785 obj->tlsinitsize);
5786 if (obj->tlsinit) {
5787 memcpy(addr, obj->tlsinit, obj->tlsinitsize);
5788 obj->static_tls_copied = true;
5789 }
5790 dtv->dtv_slots[obj->tlsindex - 1].dtvs_tls = addr;
5791 }
5792 }
5793
5794 tcb_list_insert(tcb);
5795 return (tcb);
5796 }
5797
5798 void
free_tls(void * tcb,size_t tcbsize __unused,size_t tcbalign)5799 free_tls(void *tcb, size_t tcbsize __unused, size_t tcbalign)
5800 {
5801 struct dtv *dtv;
5802 size_t size, ralign;
5803 size_t i;
5804 uintptr_t tlsstart, tlsend;
5805
5806 tcb_list_remove(tcb);
5807
5808 /*
5809 * Figure out the size of the initial TLS block so that we can
5810 * find stuff which ___tls_get_addr() allocated dynamically.
5811 */
5812 ralign = tcbalign;
5813 if (tls_static_max_align > ralign)
5814 ralign = tls_static_max_align;
5815 size = roundup(tls_static_space, ralign);
5816
5817 dtv = ((struct tcb *)tcb)->tcb_dtv;
5818 tlsend = (uintptr_t)tcb;
5819 tlsstart = tlsend - size;
5820 for (i = 0; i < dtv->dtv_size; i++) {
5821 if (dtv->dtv_slots[i].dtvs_tls != NULL &&
5822 ((uintptr_t)dtv->dtv_slots[i].dtvs_tls < tlsstart ||
5823 (uintptr_t)dtv->dtv_slots[i].dtvs_tls > tlsend)) {
5824 free(dtv->dtv_slots[i].dtvs_tls);
5825 }
5826 }
5827
5828 free((void *)tlsstart);
5829 free(dtv);
5830 }
5831
5832 #endif /* TLS_VARIANT_II */
5833
5834 /*
5835 * Allocate TLS block for module with given index.
5836 */
5837 void *
allocate_module_tls(struct tcb * tcb,int index)5838 allocate_module_tls(struct tcb *tcb, int index)
5839 {
5840 Obj_Entry *obj;
5841 char *p;
5842
5843 TAILQ_FOREACH(obj, &obj_list, next) {
5844 if (obj->marker)
5845 continue;
5846 if (obj->tlsindex == index)
5847 break;
5848 }
5849 if (obj == NULL) {
5850 _rtld_error("Can't find module with TLS index %d", index);
5851 rtld_die();
5852 }
5853
5854 if (obj->tls_static) {
5855 #ifdef TLS_VARIANT_I
5856 p = (char *)tcb + obj->tlsoffset;
5857 #else
5858 p = (char *)tcb - obj->tlsoffset;
5859 #endif
5860 return (p);
5861 }
5862
5863 obj->tls_dynamic = true;
5864
5865 p = xmalloc_aligned(obj->tlssize, obj->tlsalign, obj->tlspoffset);
5866 memcpy(p, obj->tlsinit, obj->tlsinitsize);
5867 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
5868 return (p);
5869 }
5870
5871 static bool
allocate_tls_offset_common(size_t * offp,size_t tlssize,size_t tlsalign,size_t tlspoffset __unused)5872 allocate_tls_offset_common(size_t *offp, size_t tlssize, size_t tlsalign,
5873 size_t tlspoffset __unused)
5874 {
5875 size_t off;
5876
5877 if (tls_last_offset == 0)
5878 off = calculate_first_tls_offset(tlssize, tlsalign,
5879 tlspoffset);
5880 else
5881 off = calculate_tls_offset(tls_last_offset, tls_last_size,
5882 tlssize, tlsalign, tlspoffset);
5883
5884 *offp = off;
5885 #ifdef TLS_VARIANT_I
5886 off += tlssize;
5887 #endif
5888
5889 /*
5890 * If we have already fixed the size of the static TLS block, we
5891 * must stay within that size. When allocating the static TLS, we
5892 * leave a small amount of space spare to be used for dynamically
5893 * loading modules which use static TLS.
5894 */
5895 if (tls_static_space != 0) {
5896 if (off > tls_static_space)
5897 return (false);
5898 } else if (tlsalign > tls_static_max_align) {
5899 tls_static_max_align = tlsalign;
5900 }
5901
5902 tls_last_offset = off;
5903 tls_last_size = tlssize;
5904
5905 return (true);
5906 }
5907
5908 bool
allocate_tls_offset(Obj_Entry * obj)5909 allocate_tls_offset(Obj_Entry *obj)
5910 {
5911 if (obj->tls_dynamic)
5912 return (false);
5913
5914 if (obj->tls_static)
5915 return (true);
5916
5917 if (obj->tlssize == 0) {
5918 obj->tls_static = true;
5919 return (true);
5920 }
5921
5922 if (!allocate_tls_offset_common(&obj->tlsoffset, obj->tlssize,
5923 obj->tlsalign, obj->tlspoffset))
5924 return (false);
5925
5926 obj->tls_static = true;
5927
5928 return (true);
5929 }
5930
5931 void
free_tls_offset(Obj_Entry * obj)5932 free_tls_offset(Obj_Entry *obj)
5933 {
5934 /*
5935 * If we were the last thing to allocate out of the static TLS
5936 * block, we give our space back to the 'allocator'. This is a
5937 * simplistic workaround to allow libGL.so.1 to be loaded and
5938 * unloaded multiple times.
5939 */
5940 size_t off = obj->tlsoffset;
5941
5942 #ifdef TLS_VARIANT_I
5943 off += obj->tlssize;
5944 #endif
5945 if (off == tls_last_offset) {
5946 tls_last_offset -= obj->tlssize;
5947 tls_last_size = 0;
5948 }
5949 }
5950
5951 void *
_rtld_allocate_tls(void * oldtcb,size_t tcbsize,size_t tcbalign)5952 _rtld_allocate_tls(void *oldtcb, size_t tcbsize, size_t tcbalign)
5953 {
5954 void *ret;
5955 RtldLockState lockstate;
5956
5957 wlock_acquire(rtld_bind_lock, &lockstate);
5958 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtcb,
5959 tcbsize, tcbalign);
5960 lock_release(rtld_bind_lock, &lockstate);
5961 return (ret);
5962 }
5963
5964 void
_rtld_free_tls(void * tcb,size_t tcbsize,size_t tcbalign)5965 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
5966 {
5967 RtldLockState lockstate;
5968
5969 wlock_acquire(rtld_bind_lock, &lockstate);
5970 free_tls(tcb, tcbsize, tcbalign);
5971 lock_release(rtld_bind_lock, &lockstate);
5972 }
5973
5974 static void
object_add_name(Obj_Entry * obj,const char * name)5975 object_add_name(Obj_Entry *obj, const char *name)
5976 {
5977 Name_Entry *entry;
5978 size_t len;
5979
5980 len = strlen(name);
5981 entry = malloc(sizeof(Name_Entry) + len);
5982
5983 if (entry != NULL) {
5984 strcpy(entry->name, name);
5985 STAILQ_INSERT_TAIL(&obj->names, entry, link);
5986 }
5987 }
5988
5989 static int
object_match_name(const Obj_Entry * obj,const char * name)5990 object_match_name(const Obj_Entry *obj, const char *name)
5991 {
5992 Name_Entry *entry;
5993
5994 STAILQ_FOREACH(entry, &obj->names, link) {
5995 if (strcmp(name, entry->name) == 0)
5996 return (1);
5997 }
5998 return (0);
5999 }
6000
6001 static Obj_Entry *
locate_dependency(const Obj_Entry * obj,const char * name)6002 locate_dependency(const Obj_Entry *obj, const char *name)
6003 {
6004 const Objlist_Entry *entry;
6005 const Needed_Entry *needed;
6006
6007 STAILQ_FOREACH(entry, &list_main, link) {
6008 if (object_match_name(entry->obj, name))
6009 return (entry->obj);
6010 }
6011
6012 for (needed = obj->needed; needed != NULL; needed = needed->next) {
6013 if (strcmp(obj->strtab + needed->name, name) == 0 ||
6014 (needed->obj != NULL && object_match_name(needed->obj,
6015 name))) {
6016 /*
6017 * If there is DT_NEEDED for the name we are looking
6018 * for, we are all set. Note that object might not be
6019 * found if dependency was not loaded yet, so the
6020 * function can return NULL here. This is expected and
6021 * handled properly by the caller.
6022 */
6023 return (needed->obj);
6024 }
6025 }
6026 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
6027 obj->path, name);
6028 rtld_die();
6029 }
6030
6031 static int
check_object_provided_version(Obj_Entry * refobj,const Obj_Entry * depobj,const Elf_Vernaux * vna)6032 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
6033 const Elf_Vernaux *vna)
6034 {
6035 const Elf_Verdef *vd;
6036 const char *vername;
6037
6038 vername = refobj->strtab + vna->vna_name;
6039 vd = depobj->verdef;
6040 if (vd == NULL) {
6041 _rtld_error("%s: version %s required by %s not defined",
6042 depobj->path, vername, refobj->path);
6043 return (-1);
6044 }
6045 for (;;) {
6046 if (vd->vd_version != VER_DEF_CURRENT) {
6047 _rtld_error(
6048 "%s: Unsupported version %d of Elf_Verdef entry",
6049 depobj->path, vd->vd_version);
6050 return (-1);
6051 }
6052 if (vna->vna_hash == vd->vd_hash) {
6053 const Elf_Verdaux *aux =
6054 (const Elf_Verdaux *)((const char *)vd +
6055 vd->vd_aux);
6056 if (strcmp(vername, depobj->strtab + aux->vda_name) ==
6057 0)
6058 return (0);
6059 }
6060 if (vd->vd_next == 0)
6061 break;
6062 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
6063 }
6064 if (vna->vna_flags & VER_FLG_WEAK)
6065 return (0);
6066 _rtld_error("%s: version %s required by %s not found", depobj->path,
6067 vername, refobj->path);
6068 return (-1);
6069 }
6070
6071 static int
rtld_verify_object_versions(Obj_Entry * obj)6072 rtld_verify_object_versions(Obj_Entry *obj)
6073 {
6074 const Elf_Verneed *vn;
6075 const Elf_Verdef *vd;
6076 const Elf_Verdaux *vda;
6077 const Elf_Vernaux *vna;
6078 const Obj_Entry *depobj;
6079 int maxvernum, vernum;
6080
6081 if (obj->ver_checked)
6082 return (0);
6083 obj->ver_checked = true;
6084
6085 maxvernum = 0;
6086 /*
6087 * Walk over defined and required version records and figure out
6088 * max index used by any of them. Do very basic sanity checking
6089 * while there.
6090 */
6091 vn = obj->verneed;
6092 while (vn != NULL) {
6093 if (vn->vn_version != VER_NEED_CURRENT) {
6094 _rtld_error(
6095 "%s: Unsupported version %d of Elf_Verneed entry",
6096 obj->path, vn->vn_version);
6097 return (-1);
6098 }
6099 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux);
6100 for (;;) {
6101 vernum = VER_NEED_IDX(vna->vna_other);
6102 if (vernum > maxvernum)
6103 maxvernum = vernum;
6104 if (vna->vna_next == 0)
6105 break;
6106 vna = (const Elf_Vernaux *)((const char *)vna +
6107 vna->vna_next);
6108 }
6109 if (vn->vn_next == 0)
6110 break;
6111 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next);
6112 }
6113
6114 vd = obj->verdef;
6115 while (vd != NULL) {
6116 if (vd->vd_version != VER_DEF_CURRENT) {
6117 _rtld_error(
6118 "%s: Unsupported version %d of Elf_Verdef entry",
6119 obj->path, vd->vd_version);
6120 return (-1);
6121 }
6122 vernum = VER_DEF_IDX(vd->vd_ndx);
6123 if (vernum > maxvernum)
6124 maxvernum = vernum;
6125 if (vd->vd_next == 0)
6126 break;
6127 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
6128 }
6129
6130 if (maxvernum == 0)
6131 return (0);
6132
6133 /*
6134 * Store version information in array indexable by version index.
6135 * Verify that object version requirements are satisfied along the
6136 * way.
6137 */
6138 obj->vernum = maxvernum + 1;
6139 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
6140
6141 vd = obj->verdef;
6142 while (vd != NULL) {
6143 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
6144 vernum = VER_DEF_IDX(vd->vd_ndx);
6145 assert(vernum <= maxvernum);
6146 vda = (const Elf_Verdaux *)((const char *)vd +
6147 vd->vd_aux);
6148 obj->vertab[vernum].hash = vd->vd_hash;
6149 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
6150 obj->vertab[vernum].file = NULL;
6151 obj->vertab[vernum].flags = 0;
6152 }
6153 if (vd->vd_next == 0)
6154 break;
6155 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
6156 }
6157
6158 vn = obj->verneed;
6159 while (vn != NULL) {
6160 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
6161 if (depobj == NULL)
6162 return (-1);
6163 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux);
6164 for (;;) {
6165 if (check_object_provided_version(obj, depobj, vna))
6166 return (-1);
6167 vernum = VER_NEED_IDX(vna->vna_other);
6168 assert(vernum <= maxvernum);
6169 obj->vertab[vernum].hash = vna->vna_hash;
6170 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
6171 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
6172 obj->vertab[vernum].flags = (vna->vna_other &
6173 VER_NEED_HIDDEN) != 0 ? VER_INFO_HIDDEN : 0;
6174 if (vna->vna_next == 0)
6175 break;
6176 vna = (const Elf_Vernaux *)((const char *)vna +
6177 vna->vna_next);
6178 }
6179 if (vn->vn_next == 0)
6180 break;
6181 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next);
6182 }
6183 return (0);
6184 }
6185
6186 static int
rtld_verify_versions(const Objlist * objlist)6187 rtld_verify_versions(const Objlist *objlist)
6188 {
6189 Objlist_Entry *entry;
6190 int rc;
6191
6192 rc = 0;
6193 STAILQ_FOREACH(entry, objlist, link) {
6194 /*
6195 * Skip dummy objects or objects that have their version
6196 * requirements already checked.
6197 */
6198 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
6199 continue;
6200 if (rtld_verify_object_versions(entry->obj) == -1) {
6201 rc = -1;
6202 if (ld_tracing == NULL)
6203 break;
6204 }
6205 }
6206 if (rc == 0 || ld_tracing != NULL)
6207 rc = rtld_verify_object_versions(&obj_rtld);
6208 return (rc);
6209 }
6210
6211 const Ver_Entry *
fetch_ventry(const Obj_Entry * obj,unsigned long symnum)6212 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
6213 {
6214 Elf_Versym vernum;
6215
6216 if (obj->vertab) {
6217 vernum = VER_NDX(obj->versyms[symnum]);
6218 if (vernum >= obj->vernum) {
6219 _rtld_error("%s: symbol %s has wrong verneed value %d",
6220 obj->path, obj->strtab + symnum, vernum);
6221 } else if (obj->vertab[vernum].hash != 0) {
6222 return (&obj->vertab[vernum]);
6223 }
6224 }
6225 return (NULL);
6226 }
6227
6228 int
_rtld_get_stack_prot(void)6229 _rtld_get_stack_prot(void)
6230 {
6231 return (stack_prot);
6232 }
6233
6234 int
_rtld_is_dlopened(void * arg)6235 _rtld_is_dlopened(void *arg)
6236 {
6237 Obj_Entry *obj;
6238 RtldLockState lockstate;
6239 int res;
6240
6241 rlock_acquire(rtld_bind_lock, &lockstate);
6242 obj = dlcheck(arg);
6243 if (obj == NULL)
6244 obj = obj_from_addr(arg);
6245 if (obj == NULL) {
6246 _rtld_error("No shared object contains address");
6247 lock_release(rtld_bind_lock, &lockstate);
6248 return (-1);
6249 }
6250 res = obj->dlopened ? 1 : 0;
6251 lock_release(rtld_bind_lock, &lockstate);
6252 return (res);
6253 }
6254
6255 static int
obj_remap_relro(Obj_Entry * obj,int prot)6256 obj_remap_relro(Obj_Entry *obj, int prot)
6257 {
6258 const Elf_Phdr *ph;
6259 caddr_t relro_page;
6260 size_t relro_size;
6261
6262 for (ph = obj->phdr; ph < obj->phdr + obj->phnum; ph++) {
6263 if (ph->p_type != PT_GNU_RELRO)
6264 continue;
6265 relro_page = obj->relocbase + rtld_trunc_page(ph->p_vaddr);
6266 relro_size = rtld_round_page(ph->p_vaddr + ph->p_memsz) -
6267 rtld_trunc_page(ph->p_vaddr);
6268 if (mprotect(relro_page, relro_size, prot) == -1) {
6269 _rtld_error(
6270 "%s: Cannot set relro protection to %#x: %s",
6271 obj->path, prot, rtld_strerror(errno));
6272 return (-1);
6273 }
6274 break;
6275 }
6276 return (0);
6277 }
6278
6279 static int
obj_disable_relro(Obj_Entry * obj)6280 obj_disable_relro(Obj_Entry *obj)
6281 {
6282 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE));
6283 }
6284
6285 static int
obj_enforce_relro(Obj_Entry * obj)6286 obj_enforce_relro(Obj_Entry *obj)
6287 {
6288 return (obj_remap_relro(obj, PROT_READ));
6289 }
6290
6291 static void
map_stacks_exec(RtldLockState * lockstate)6292 map_stacks_exec(RtldLockState *lockstate)
6293 {
6294 void (*thr_map_stacks_exec)(void);
6295
6296 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
6297 return;
6298 thr_map_stacks_exec = (void (*)(void))(
6299 uintptr_t)get_program_var_addr("__pthread_map_stacks_exec",
6300 lockstate);
6301 if (thr_map_stacks_exec != NULL) {
6302 stack_prot |= PROT_EXEC;
6303 thr_map_stacks_exec();
6304 }
6305 }
6306
6307 static void
distribute_static_tls(Objlist * list)6308 distribute_static_tls(Objlist *list)
6309 {
6310 struct tcb_list_entry *tcbelm;
6311 Objlist_Entry *objelm;
6312 struct tcb *tcb;
6313 Obj_Entry *obj;
6314 char *tlsbase;
6315
6316 STAILQ_FOREACH(objelm, list, link) {
6317 obj = objelm->obj;
6318 if (obj->marker || !obj->tls_static || obj->static_tls_copied)
6319 continue;
6320 TAILQ_FOREACH(tcbelm, &tcb_list, next) {
6321 tcb = tcb_from_tcb_list_entry(tcbelm);
6322 #ifdef TLS_VARIANT_I
6323 tlsbase = (char *)tcb + obj->tlsoffset;
6324 #else
6325 tlsbase = (char *)tcb - obj->tlsoffset;
6326 #endif
6327 memcpy(tlsbase, obj->tlsinit, obj->tlsinitsize);
6328 memset(tlsbase + obj->tlsinitsize, 0,
6329 obj->tlssize - obj->tlsinitsize);
6330 }
6331 obj->static_tls_copied = true;
6332 }
6333 }
6334
6335 void
symlook_init(SymLook * dst,const char * name)6336 symlook_init(SymLook *dst, const char *name)
6337 {
6338 bzero(dst, sizeof(*dst));
6339 dst->name = name;
6340 dst->hash = elf_hash(name);
6341 dst->hash_gnu = gnu_hash(name);
6342 }
6343
6344 static void
symlook_init_from_req(SymLook * dst,const SymLook * src)6345 symlook_init_from_req(SymLook *dst, const SymLook *src)
6346 {
6347 dst->name = src->name;
6348 dst->hash = src->hash;
6349 dst->hash_gnu = src->hash_gnu;
6350 dst->ventry = src->ventry;
6351 dst->flags = src->flags;
6352 dst->defobj_out = NULL;
6353 dst->sym_out = NULL;
6354 dst->lockstate = src->lockstate;
6355 dst->donelist_mem = NULL;
6356 }
6357
6358 static int
open_binary_fd(const char * argv0,bool search_in_path,const char ** binpath_res)6359 open_binary_fd(const char *argv0, bool search_in_path, const char **binpath_res)
6360 {
6361 char *binpath, *pathenv, *pe, *res1;
6362 const char *res;
6363 int fd;
6364
6365 binpath = NULL;
6366 res = NULL;
6367 if (search_in_path && strchr(argv0, '/') == NULL) {
6368 binpath = xmalloc(PATH_MAX);
6369 pathenv = getenv("PATH");
6370 if (pathenv == NULL) {
6371 _rtld_error("-p and no PATH environment variable");
6372 rtld_die();
6373 }
6374 pathenv = strdup(pathenv);
6375 if (pathenv == NULL) {
6376 _rtld_error("Cannot allocate memory");
6377 rtld_die();
6378 }
6379 fd = -1;
6380 errno = ENOENT;
6381 while ((pe = strsep(&pathenv, ":")) != NULL) {
6382 if (strlcpy(binpath, pe, PATH_MAX) >= PATH_MAX)
6383 continue;
6384 if (binpath[0] != '\0' &&
6385 strlcat(binpath, "/", PATH_MAX) >= PATH_MAX)
6386 continue;
6387 if (strlcat(binpath, argv0, PATH_MAX) >= PATH_MAX)
6388 continue;
6389 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY);
6390 if (fd != -1 || errno != ENOENT) {
6391 res = binpath;
6392 break;
6393 }
6394 }
6395 free(pathenv);
6396 } else {
6397 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY);
6398 res = argv0;
6399 }
6400
6401 if (fd == -1) {
6402 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno));
6403 rtld_die();
6404 }
6405 if (res != NULL && res[0] != '/') {
6406 res1 = xmalloc(PATH_MAX);
6407 if (realpath(res, res1) != NULL) {
6408 if (res != argv0)
6409 free(__DECONST(char *, res));
6410 res = res1;
6411 } else {
6412 free(res1);
6413 }
6414 }
6415 *binpath_res = res;
6416 return (fd);
6417 }
6418
6419 /*
6420 * Parse a set of command-line arguments.
6421 */
6422 static int
parse_args(char * argv[],int argc,bool * use_pathp,int * fdp,const char ** argv0,bool * dir_ignore)6423 parse_args(char *argv[], int argc, bool *use_pathp, int *fdp,
6424 const char **argv0, bool *dir_ignore)
6425 {
6426 const char *arg;
6427 char machine[64];
6428 size_t sz;
6429 int arglen, fd, i, j, mib[2];
6430 char opt;
6431 bool seen_b, seen_f;
6432
6433 dbg("Parsing command-line arguments");
6434 *use_pathp = false;
6435 *fdp = -1;
6436 *dir_ignore = false;
6437 seen_b = seen_f = false;
6438
6439 for (i = 1; i < argc; i++) {
6440 arg = argv[i];
6441 dbg("argv[%d]: '%s'", i, arg);
6442
6443 /*
6444 * rtld arguments end with an explicit "--" or with the first
6445 * non-prefixed argument.
6446 */
6447 if (strcmp(arg, "--") == 0) {
6448 i++;
6449 break;
6450 }
6451 if (arg[0] != '-')
6452 break;
6453
6454 /*
6455 * All other arguments are single-character options that can
6456 * be combined, so we need to search through `arg` for them.
6457 */
6458 arglen = strlen(arg);
6459 for (j = 1; j < arglen; j++) {
6460 opt = arg[j];
6461 if (opt == 'h') {
6462 print_usage(argv[0]);
6463 _exit(0);
6464 } else if (opt == 'b') {
6465 if (seen_f) {
6466 _rtld_error("Both -b and -f specified");
6467 rtld_die();
6468 }
6469 if (j != arglen - 1) {
6470 _rtld_error("Invalid options: %s", arg);
6471 rtld_die();
6472 }
6473 i++;
6474 *argv0 = argv[i];
6475 seen_b = true;
6476 break;
6477 } else if (opt == 'd') {
6478 *dir_ignore = true;
6479 } else if (opt == 'f') {
6480 if (seen_b) {
6481 _rtld_error("Both -b and -f specified");
6482 rtld_die();
6483 }
6484
6485 /*
6486 * -f XX can be used to specify a
6487 * descriptor for the binary named at
6488 * the command line (i.e., the later
6489 * argument will specify the process
6490 * name but the descriptor is what
6491 * will actually be executed).
6492 *
6493 * -f must be the last option in the
6494 * group, e.g., -abcf <fd>.
6495 */
6496 if (j != arglen - 1) {
6497 _rtld_error("Invalid options: %s", arg);
6498 rtld_die();
6499 }
6500 i++;
6501 fd = parse_integer(argv[i]);
6502 if (fd == -1) {
6503 _rtld_error(
6504 "Invalid file descriptor: '%s'",
6505 argv[i]);
6506 rtld_die();
6507 }
6508 *fdp = fd;
6509 seen_f = true;
6510 break;
6511 } else if (opt == 'o') {
6512 struct ld_env_var_desc *l;
6513 char *n, *v;
6514 u_int ll;
6515
6516 if (j != arglen - 1) {
6517 _rtld_error("Invalid options: %s", arg);
6518 rtld_die();
6519 }
6520 i++;
6521 n = argv[i];
6522 v = strchr(n, '=');
6523 if (v == NULL) {
6524 _rtld_error("No '=' in -o parameter");
6525 rtld_die();
6526 }
6527 for (ll = 0; ll < nitems(ld_env_vars); ll++) {
6528 l = &ld_env_vars[ll];
6529 if (v - n == (ptrdiff_t)strlen(l->n) &&
6530 strncmp(n, l->n, v - n) == 0) {
6531 l->val = v + 1;
6532 break;
6533 }
6534 }
6535 if (ll == nitems(ld_env_vars)) {
6536 _rtld_error("Unknown LD_ option %s", n);
6537 rtld_die();
6538 }
6539 } else if (opt == 'p') {
6540 *use_pathp = true;
6541 } else if (opt == 'u') {
6542 u_int ll;
6543
6544 for (ll = 0; ll < nitems(ld_env_vars); ll++)
6545 ld_env_vars[ll].val = NULL;
6546 } else if (opt == 'v') {
6547 machine[0] = '\0';
6548 mib[0] = CTL_HW;
6549 mib[1] = HW_MACHINE;
6550 sz = sizeof(machine);
6551 sysctl(mib, nitems(mib), machine, &sz, NULL, 0);
6552 ld_elf_hints_path = ld_get_env_var(
6553 LD_ELF_HINTS_PATH);
6554 set_ld_elf_hints_path();
6555 rtld_printf(
6556 "FreeBSD ld-elf.so.1 %s\n"
6557 "FreeBSD_version %d\n"
6558 "Default lib path %s\n"
6559 "Hints lib path %s\n"
6560 "Env prefix %s\n"
6561 "Default hint file %s\n"
6562 "Hint file %s\n"
6563 "libmap file %s\n"
6564 "Optional static TLS size %zd bytes\n",
6565 machine, __FreeBSD_version,
6566 ld_standard_library_path, gethints(false),
6567 ld_env_prefix, ld_elf_hints_default,
6568 ld_elf_hints_path, ld_path_libmap_conf,
6569 ld_static_tls_extra);
6570 _exit(0);
6571 } else {
6572 _rtld_error("Invalid argument: '%s'", arg);
6573 print_usage(argv[0]);
6574 rtld_die();
6575 }
6576 }
6577 }
6578
6579 if (!seen_b)
6580 *argv0 = argv[i];
6581 return (i);
6582 }
6583
6584 /*
6585 * Parse a file descriptor number without pulling in more of libc (e.g. atoi).
6586 */
6587 static int
parse_integer(const char * str)6588 parse_integer(const char *str)
6589 {
6590 int radix;
6591 const char *orig;
6592 int n, val;
6593 char c;
6594
6595 if (str[0] == '0') {
6596 if (str[1] == 'x') {
6597 str += 2;
6598 radix = 16;
6599 } else if (str[1] == 'b') {
6600 str += 2;
6601 radix = 2;
6602 } else {
6603 str += 1;
6604 radix = 8;
6605 }
6606 } else {
6607 radix = 10;
6608 }
6609 orig = str;
6610 n = 0;
6611 for (c = *str; c != '\0'; c = *++str) {
6612 if (c >= '0' && c <= '9')
6613 val = c - '0';
6614 else if (c >= 'a' && c <= 'f')
6615 val = c - 'a' + 10;
6616 else if (c >= 'A' && c <= 'F')
6617 val = c - 'A' + 10;
6618 else
6619 return (-1);
6620 if (val >= radix)
6621 return (-1);
6622
6623 if (n > INT_MAX / radix)
6624 return (-1);
6625 n *= radix;
6626 if (n > INT_MAX - val)
6627 return (-1);
6628 n += val;
6629 }
6630
6631 /*
6632 * Make sure we actually parsed something.
6633 * Allow for lone '0'.
6634 */
6635 if (str == orig && radix != 8)
6636 return (-1);
6637 return (n);
6638 }
6639
6640 static void
print_usage(const char * argv0)6641 print_usage(const char *argv0)
6642 {
6643 rtld_printf(
6644 "Usage: %s [-h] [-b <exe>] [-d] [-f <FD>] [-p] [--] <binary> [<args>]\n"
6645 "\n"
6646 "Options:\n"
6647 " -h Display this help message\n"
6648 " -b <exe> Execute <exe> instead of <binary>, arg0 is <binary>\n"
6649 " -d Ignore lack of exec permissions for the binary\n"
6650 " -f <FD> Execute <FD> instead of searching for <binary>\n"
6651 " -o <OPT>=<VAL> Set LD_<OPT> to <VAL>, without polluting env\n"
6652 " -p Search in PATH for named binary\n"
6653 " -u Ignore LD_ environment variables\n"
6654 " -v Display identification information\n"
6655 " -- End of RTLD options\n"
6656 " <binary> Name of process to execute\n"
6657 " <args> Arguments to the executed process\n",
6658 argv0);
6659 }
6660
6661 #define AUXFMT(at, xfmt) [at] = { .name = #at, .fmt = xfmt }
6662 static const struct auxfmt {
6663 const char *name;
6664 const char *fmt;
6665 } auxfmts[] = {
6666 AUXFMT(AT_NULL, NULL),
6667 AUXFMT(AT_IGNORE, NULL),
6668 AUXFMT(AT_EXECFD, "%ld"),
6669 AUXFMT(AT_PHDR, "%p"),
6670 AUXFMT(AT_PHENT, "%lu"),
6671 AUXFMT(AT_PHNUM, "%lu"),
6672 AUXFMT(AT_PAGESZ, "%lu"),
6673 AUXFMT(AT_BASE, "%#lx"),
6674 AUXFMT(AT_FLAGS, "%#lx"),
6675 AUXFMT(AT_ENTRY, "%p"),
6676 AUXFMT(AT_NOTELF, NULL),
6677 AUXFMT(AT_UID, "%ld"),
6678 AUXFMT(AT_EUID, "%ld"),
6679 AUXFMT(AT_GID, "%ld"),
6680 AUXFMT(AT_EGID, "%ld"),
6681 AUXFMT(AT_EXECPATH, "%s"),
6682 AUXFMT(AT_CANARY, "%p"),
6683 AUXFMT(AT_CANARYLEN, "%lu"),
6684 AUXFMT(AT_OSRELDATE, "%lu"),
6685 AUXFMT(AT_NCPUS, "%lu"),
6686 AUXFMT(AT_PAGESIZES, "%p"),
6687 AUXFMT(AT_PAGESIZESLEN, "%lu"),
6688 AUXFMT(AT_TIMEKEEP, "%p"),
6689 AUXFMT(AT_STACKPROT, "%#lx"),
6690 AUXFMT(AT_EHDRFLAGS, "%#lx"),
6691 AUXFMT(AT_HWCAP, "%#lx"),
6692 AUXFMT(AT_HWCAP2, "%#lx"),
6693 AUXFMT(AT_BSDFLAGS, "%#lx"),
6694 AUXFMT(AT_ARGC, "%lu"),
6695 AUXFMT(AT_ARGV, "%p"),
6696 AUXFMT(AT_ENVC, "%p"),
6697 AUXFMT(AT_ENVV, "%p"),
6698 AUXFMT(AT_PS_STRINGS, "%p"),
6699 AUXFMT(AT_FXRNG, "%p"),
6700 AUXFMT(AT_KPRELOAD, "%p"),
6701 AUXFMT(AT_USRSTACKBASE, "%#lx"),
6702 AUXFMT(AT_USRSTACKLIM, "%#lx"),
6703 /* AT_CHERI_STATS */
6704 AUXFMT(AT_HWCAP3, "%#lx"),
6705 AUXFMT(AT_HWCAP4, "%#lx"),
6706
6707 };
6708
6709 static bool
is_ptr_fmt(const char * fmt)6710 is_ptr_fmt(const char *fmt)
6711 {
6712 char last;
6713
6714 last = fmt[strlen(fmt) - 1];
6715 return (last == 'p' || last == 's');
6716 }
6717
6718 static void
dump_auxv(Elf_Auxinfo ** aux_info)6719 dump_auxv(Elf_Auxinfo **aux_info)
6720 {
6721 Elf_Auxinfo *auxp;
6722 const struct auxfmt *fmt;
6723 int i;
6724
6725 for (i = 0; i < AT_COUNT; i++) {
6726 auxp = aux_info[i];
6727 if (auxp == NULL)
6728 continue;
6729 fmt = &auxfmts[i];
6730 if (fmt->fmt == NULL)
6731 continue;
6732 rtld_fdprintf(STDOUT_FILENO, "%s:\t", fmt->name);
6733 if (is_ptr_fmt(fmt->fmt)) {
6734 rtld_fdprintfx(STDOUT_FILENO, fmt->fmt,
6735 auxp->a_un.a_ptr);
6736 } else {
6737 rtld_fdprintfx(STDOUT_FILENO, fmt->fmt,
6738 auxp->a_un.a_val);
6739 }
6740 rtld_fdprintf(STDOUT_FILENO, "\n");
6741 }
6742 }
6743
6744 const char *
rtld_get_var(const char * name)6745 rtld_get_var(const char *name)
6746 {
6747 const struct ld_env_var_desc *lvd;
6748 u_int i;
6749
6750 for (i = 0; i < nitems(ld_env_vars); i++) {
6751 lvd = &ld_env_vars[i];
6752 if (strcmp(lvd->n, name) == 0)
6753 return (lvd->val);
6754 }
6755 return (NULL);
6756 }
6757
6758 static void
rtld_recalc_dangerous_ld_env(void)6759 rtld_recalc_dangerous_ld_env(void)
6760 {
6761 /*
6762 * Never reset dangerous_ld_env back to false if rtld was ever
6763 * contaminated with it set to true.
6764 */
6765 dangerous_ld_env |= libmap_disable || libmap_override != NULL ||
6766 ld_library_path != NULL || ld_preload != NULL ||
6767 ld_elf_hints_path != NULL || ld_loadfltr || !ld_dynamic_weak ||
6768 ld_get_env_var(LD_STATIC_TLS_EXTRA) != NULL;
6769 }
6770
6771 static void
rtld_recalc_debug(const char * ld_debug)6772 rtld_recalc_debug(const char *ld_debug)
6773 {
6774 if (ld_debug != NULL && *ld_debug != '\0')
6775 debug = 1;
6776 }
6777
6778 static void
rtld_set_var_debug(struct ld_env_var_desc * lvd)6779 rtld_set_var_debug(struct ld_env_var_desc *lvd)
6780 {
6781 rtld_recalc_debug(lvd->val);
6782 }
6783
6784 static void
rtld_set_var_library_path(struct ld_env_var_desc * lvd)6785 rtld_set_var_library_path(struct ld_env_var_desc *lvd)
6786 {
6787 ld_library_path = lvd->val;
6788 }
6789
6790 static void
rtld_set_var_library_path_fds(struct ld_env_var_desc * lvd)6791 rtld_set_var_library_path_fds(struct ld_env_var_desc *lvd)
6792 {
6793 ld_library_dirs = lvd->val;
6794 }
6795
6796 static void
rtld_recalc_path_rpath(const char * library_path_rpath)6797 rtld_recalc_path_rpath(const char *library_path_rpath)
6798 {
6799 if (library_path_rpath != NULL) {
6800 if (library_path_rpath[0] == 'y' ||
6801 library_path_rpath[0] == 'Y' ||
6802 library_path_rpath[0] == '1')
6803 ld_library_path_rpath = true;
6804 else
6805 ld_library_path_rpath = false;
6806 } else {
6807 ld_library_path_rpath = false;
6808 }
6809 }
6810
6811 static void
rtld_set_var_library_path_rpath(struct ld_env_var_desc * lvd)6812 rtld_set_var_library_path_rpath(struct ld_env_var_desc *lvd)
6813 {
6814 rtld_recalc_path_rpath(lvd->val);
6815 }
6816
6817 static void
rtld_recalc_bind_not(const char * bind_not_val)6818 rtld_recalc_bind_not(const char *bind_not_val)
6819 {
6820 if (ld_bind_now == NULL)
6821 ld_bind_not = bind_not_val != NULL;
6822 }
6823
6824 static void
rtld_set_var_bind_now(struct ld_env_var_desc * lvd)6825 rtld_set_var_bind_now(struct ld_env_var_desc *lvd)
6826 {
6827 ld_bind_now = lvd->val;
6828 rtld_recalc_bind_not(ld_get_env_var(LD_BIND_NOT));
6829 }
6830
6831 static void
rtld_set_var_bind_not(struct ld_env_var_desc * lvd)6832 rtld_set_var_bind_not(struct ld_env_var_desc *lvd)
6833 {
6834 rtld_recalc_bind_not(lvd->val);
6835 }
6836
6837 static void
rtld_set_var_dynamic_weak(struct ld_env_var_desc * lvd)6838 rtld_set_var_dynamic_weak(struct ld_env_var_desc *lvd)
6839 {
6840 ld_dynamic_weak = lvd->val == NULL;
6841 }
6842
6843 static void
rtld_set_var_loadfltr(struct ld_env_var_desc * lvd)6844 rtld_set_var_loadfltr(struct ld_env_var_desc *lvd)
6845 {
6846 ld_loadfltr = lvd->val != NULL;
6847 }
6848
6849 static void
rtld_set_var_libmap_disable(struct ld_env_var_desc * lvd)6850 rtld_set_var_libmap_disable(struct ld_env_var_desc *lvd)
6851 {
6852 libmap_disable = lvd->val != NULL;
6853 }
6854
6855 int
rtld_set_var(const char * name,const char * val)6856 rtld_set_var(const char *name, const char *val)
6857 {
6858 RtldLockState lockstate;
6859 struct ld_env_var_desc *lvd;
6860 u_int i;
6861 int error;
6862
6863 error = ENOENT;
6864 wlock_acquire(rtld_bind_lock, &lockstate);
6865 for (i = 0; i < nitems(ld_env_vars); i++) {
6866 lvd = &ld_env_vars[i];
6867 if (strcmp(lvd->n, name) != 0)
6868 continue;
6869 if (!lvd->can_update || (lvd->unsecure && !trust)) {
6870 error = EPERM;
6871 break;
6872 }
6873 if (lvd->owned)
6874 free(__DECONST(char *, lvd->val));
6875 if (val != NULL)
6876 lvd->val = xstrdup(val);
6877 else
6878 lvd->val = NULL;
6879 lvd->owned = true;
6880 if (lvd->on_update != NULL)
6881 lvd->on_update(lvd);
6882 error = 0;
6883 break;
6884 }
6885 if (error == 0)
6886 rtld_recalc_dangerous_ld_env();
6887 lock_release(rtld_bind_lock, &lockstate);
6888 return (error);
6889 }
6890
6891 /*
6892 * Overrides for libc_pic-provided functions.
6893 */
6894
6895 int
__getosreldate(void)6896 __getosreldate(void)
6897 {
6898 size_t len;
6899 int oid[2];
6900 int error, osrel;
6901
6902 if (osreldate != 0)
6903 return (osreldate);
6904
6905 oid[0] = CTL_KERN;
6906 oid[1] = KERN_OSRELDATE;
6907 osrel = 0;
6908 len = sizeof(osrel);
6909 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
6910 if (error == 0 && osrel > 0 && len == sizeof(osrel))
6911 osreldate = osrel;
6912 return (osreldate);
6913 }
6914 const char *
rtld_strerror(int errnum)6915 rtld_strerror(int errnum)
6916 {
6917 if (errnum < 0 || errnum >= sys_nerr)
6918 return ("Unknown error");
6919 return (sys_errlist[errnum]);
6920 }
6921
6922 char *
getenv(const char * name)6923 getenv(const char *name)
6924 {
6925 return (__DECONST(char *, rtld_get_env_val(environ, name,
6926 strlen(name))));
6927 }
6928
6929 extern int _rtld_version__FreeBSD_version __exported;
6930 int _rtld_version__FreeBSD_version = __FreeBSD_version;
6931
6932 extern char _rtld_version_laddr_offset __exported;
6933 char _rtld_version_laddr_offset;
6934
6935 extern char _rtld_version_dlpi_tls_data __exported;
6936 char _rtld_version_dlpi_tls_data;
6937