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;
1789 const char *note_name;
1790 uintptr_t p;
1791
1792 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1793 note = (const Elf_Note *)((const char *)(note + 1) +
1794 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1795 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1796 if (arch_digest_note(obj, note))
1797 continue;
1798
1799 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1800 note->n_descsz != sizeof(int32_t))
1801 continue;
1802 if (note->n_type != NT_FREEBSD_ABI_TAG &&
1803 note->n_type != NT_FREEBSD_FEATURE_CTL &&
1804 note->n_type != NT_FREEBSD_NOINIT_TAG)
1805 continue;
1806 note_name = (const char *)(note + 1);
1807 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1808 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1809 continue;
1810 switch (note->n_type) {
1811 case NT_FREEBSD_ABI_TAG:
1812 /* FreeBSD osrel note */
1813 p = (uintptr_t)(note + 1);
1814 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1815 obj->osrel = *(const int32_t *)(p);
1816 dbg("note osrel %d", obj->osrel);
1817 break;
1818 case NT_FREEBSD_FEATURE_CTL:
1819 /* FreeBSD ABI feature control note */
1820 p = (uintptr_t)(note + 1);
1821 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1822 obj->fctl0 = *(const uint32_t *)(p);
1823 dbg("note fctl0 %#x", obj->fctl0);
1824 break;
1825 case NT_FREEBSD_NOINIT_TAG:
1826 /* FreeBSD 'crt does not call init' note */
1827 obj->crt_no_init = true;
1828 dbg("note crt_no_init");
1829 break;
1830 }
1831 }
1832 }
1833
1834 static Obj_Entry *
dlcheck(void * handle)1835 dlcheck(void *handle)
1836 {
1837 Obj_Entry *obj;
1838
1839 TAILQ_FOREACH(obj, &obj_list, next) {
1840 if (obj == (Obj_Entry *)handle)
1841 break;
1842 }
1843
1844 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1845 _rtld_error("Invalid shared object handle %p", handle);
1846 return (NULL);
1847 }
1848 return (obj);
1849 }
1850
1851 /*
1852 * If the given object is already in the donelist, return true. Otherwise
1853 * add the object to the list and return false.
1854 */
1855 static bool
donelist_check(DoneList * dlp,const Obj_Entry * obj)1856 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1857 {
1858 unsigned int i;
1859
1860 for (i = 0; i < dlp->num_used; i++)
1861 if (dlp->objs[i] == obj)
1862 return (true);
1863 /*
1864 * Our donelist allocation should always be sufficient. But if
1865 * our threads locking isn't working properly, more shared objects
1866 * could have been loaded since we allocated the list. That should
1867 * never happen, but we'll handle it properly just in case it does.
1868 */
1869 if (dlp->num_used < dlp->num_alloc)
1870 dlp->objs[dlp->num_used++] = obj;
1871 return (false);
1872 }
1873
1874 /*
1875 * SysV hash function for symbol table lookup. It is a slightly optimized
1876 * version of the hash specified by the System V ABI.
1877 */
1878 Elf32_Word
elf_hash(const char * name)1879 elf_hash(const char *name)
1880 {
1881 const unsigned char *p = (const unsigned char *)name;
1882 Elf32_Word h = 0;
1883
1884 while (*p != '\0') {
1885 h = (h << 4) + *p++;
1886 h ^= (h >> 24) & 0xf0;
1887 }
1888 return (h & 0x0fffffff);
1889 }
1890
1891 /*
1892 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1893 * unsigned in case it's implemented with a wider type.
1894 */
1895 static uint32_t
gnu_hash(const char * s)1896 gnu_hash(const char *s)
1897 {
1898 uint32_t h;
1899 unsigned char c;
1900
1901 h = 5381;
1902 for (c = *s; c != '\0'; c = *++s)
1903 h = h * 33 + c;
1904 return (h & 0xffffffff);
1905 }
1906
1907 /*
1908 * Find the library with the given name, and return its full pathname.
1909 * The returned string is dynamically allocated. Generates an error
1910 * message and returns NULL if the library cannot be found.
1911 *
1912 * If the second argument is non-NULL, then it refers to an already-
1913 * loaded shared object, whose library search path will be searched.
1914 *
1915 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its
1916 * descriptor (which is close-on-exec) will be passed out via the third
1917 * argument.
1918 *
1919 * The search order is:
1920 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1921 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1922 * LD_LIBRARY_PATH
1923 * DT_RUNPATH in the referencing file
1924 * ldconfig hints (if -z nodefaultlib, filter out default library directories
1925 * from list)
1926 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1927 *
1928 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1929 */
1930 static char *
find_library(const char * xname,const Obj_Entry * refobj,int * fdp)1931 find_library(const char *xname, const Obj_Entry *refobj, int *fdp)
1932 {
1933 char *pathname, *refobj_path;
1934 const char *name;
1935 bool nodeflib, objgiven;
1936
1937 objgiven = refobj != NULL;
1938
1939 if (libmap_disable || !objgiven ||
1940 (name = lm_find(refobj->path, xname)) == NULL)
1941 name = xname;
1942
1943 if (strchr(name, '/') != NULL) { /* Hard coded pathname */
1944 if (name[0] != '/' && !trust) {
1945 _rtld_error(
1946 "Absolute pathname required for shared object \"%s\"",
1947 name);
1948 return (NULL);
1949 }
1950 return (origin_subst(__DECONST(Obj_Entry *, refobj),
1951 __DECONST(char *, name)));
1952 }
1953
1954 dbg(" Searching for \"%s\"", name);
1955 refobj_path = objgiven ? refobj->path : NULL;
1956
1957 /*
1958 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall
1959 * back to pre-conforming behaviour if user requested so with
1960 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z
1961 * nodeflib.
1962 */
1963 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) {
1964 pathname = search_library_path(name, ld_library_path,
1965 refobj_path, fdp);
1966 if (pathname != NULL)
1967 return (pathname);
1968 if (refobj != NULL) {
1969 pathname = search_library_path(name, refobj->rpath,
1970 refobj_path, fdp);
1971 if (pathname != NULL)
1972 return (pathname);
1973 }
1974 pathname = search_library_pathfds(name, ld_library_dirs, fdp);
1975 if (pathname != NULL)
1976 return (pathname);
1977 pathname = search_library_path(name, gethints(false),
1978 refobj_path, fdp);
1979 if (pathname != NULL)
1980 return (pathname);
1981 pathname = search_library_path(name, ld_standard_library_path,
1982 refobj_path, fdp);
1983 if (pathname != NULL)
1984 return (pathname);
1985 } else {
1986 nodeflib = objgiven ? refobj->z_nodeflib : false;
1987 if (objgiven) {
1988 pathname = search_library_path(name, refobj->rpath,
1989 refobj->path, fdp);
1990 if (pathname != NULL)
1991 return (pathname);
1992 }
1993 if (objgiven && refobj->runpath == NULL && refobj != obj_main) {
1994 pathname = search_library_path(name, obj_main->rpath,
1995 refobj_path, fdp);
1996 if (pathname != NULL)
1997 return (pathname);
1998 }
1999 pathname = search_library_path(name, ld_library_path,
2000 refobj_path, fdp);
2001 if (pathname != NULL)
2002 return (pathname);
2003 if (objgiven) {
2004 pathname = search_library_path(name, refobj->runpath,
2005 refobj_path, fdp);
2006 if (pathname != NULL)
2007 return (pathname);
2008 }
2009 pathname = search_library_pathfds(name, ld_library_dirs, fdp);
2010 if (pathname != NULL)
2011 return (pathname);
2012 pathname = search_library_path(name, gethints(nodeflib),
2013 refobj_path, fdp);
2014 if (pathname != NULL)
2015 return (pathname);
2016 if (objgiven && !nodeflib) {
2017 pathname = search_library_path(name,
2018 ld_standard_library_path, refobj_path, fdp);
2019 if (pathname != NULL)
2020 return (pathname);
2021 }
2022 }
2023
2024 if (objgiven && refobj->path != NULL) {
2025 _rtld_error(
2026 "Shared object \"%s\" not found, required by \"%s\"",
2027 name, basename(refobj->path));
2028 } else {
2029 _rtld_error("Shared object \"%s\" not found", name);
2030 }
2031 return (NULL);
2032 }
2033
2034 /*
2035 * Given a symbol number in a referencing object, find the corresponding
2036 * definition of the symbol. Returns a pointer to the symbol, or NULL if
2037 * no definition was found. Returns a pointer to the Obj_Entry of the
2038 * defining object via the reference parameter DEFOBJ_OUT.
2039 */
2040 const Elf_Sym *
find_symdef(unsigned long symnum,const Obj_Entry * refobj,const Obj_Entry ** defobj_out,int flags,SymCache * cache,RtldLockState * lockstate)2041 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
2042 const Obj_Entry **defobj_out, int flags, SymCache *cache,
2043 RtldLockState *lockstate)
2044 {
2045 const Elf_Sym *ref;
2046 const Elf_Sym *def;
2047 const Obj_Entry *defobj;
2048 const Ver_Entry *ve;
2049 SymLook req;
2050 const char *name;
2051 int res;
2052
2053 /*
2054 * If we have already found this symbol, get the information from
2055 * the cache.
2056 */
2057 if (symnum >= refobj->dynsymcount)
2058 return (NULL); /* Bad object */
2059 if (cache != NULL && cache[symnum].sym != NULL) {
2060 *defobj_out = cache[symnum].obj;
2061 return (cache[symnum].sym);
2062 }
2063
2064 ref = refobj->symtab + symnum;
2065 name = refobj->strtab + ref->st_name;
2066 def = NULL;
2067 defobj = NULL;
2068 ve = NULL;
2069
2070 /*
2071 * We don't have to do a full scale lookup if the symbol is local.
2072 * We know it will bind to the instance in this load module; to
2073 * which we already have a pointer (ie ref). By not doing a lookup,
2074 * we not only improve performance, but it also avoids unresolvable
2075 * symbols when local symbols are not in the hash table. This has
2076 * been seen with the ia64 toolchain.
2077 */
2078 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
2079 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
2080 _rtld_error("%s: Bogus symbol table entry %lu",
2081 refobj->path, symnum);
2082 }
2083 symlook_init(&req, name);
2084 req.flags = flags;
2085 ve = req.ventry = fetch_ventry(refobj, symnum);
2086 req.lockstate = lockstate;
2087 res = symlook_default(&req, refobj);
2088 if (res == 0) {
2089 def = req.sym_out;
2090 defobj = req.defobj_out;
2091 }
2092 } else {
2093 def = ref;
2094 defobj = refobj;
2095 }
2096
2097 /*
2098 * If we found no definition and the reference is weak, treat the
2099 * symbol as having the value zero.
2100 */
2101 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
2102 def = &sym_zero;
2103 defobj = obj_main;
2104 }
2105
2106 if (def != NULL) {
2107 *defobj_out = defobj;
2108 /*
2109 * Record the information in the cache to avoid subsequent
2110 * lookups.
2111 */
2112 if (cache != NULL) {
2113 cache[symnum].sym = def;
2114 cache[symnum].obj = defobj;
2115 }
2116 } else {
2117 if (refobj != &obj_rtld)
2118 _rtld_error("%s: Undefined symbol \"%s%s%s\"",
2119 refobj->path, name, ve != NULL ? "@" : "",
2120 ve != NULL ? ve->name : "");
2121 }
2122 return (def);
2123 }
2124
2125 /* Convert between native byte order and forced little resp. big endian. */
2126 #define COND_SWAP(n) (is_le ? le32toh(n) : be32toh(n))
2127
2128 /*
2129 * Return the search path from the ldconfig hints file, reading it if
2130 * necessary. If nostdlib is true, then the default search paths are
2131 * not added to result.
2132 *
2133 * Returns NULL if there are problems with the hints file,
2134 * or if the search path there is empty.
2135 */
2136 static const char *
gethints(bool nostdlib)2137 gethints(bool nostdlib)
2138 {
2139 static char *filtered_path;
2140 static const char *hints;
2141 static struct elfhints_hdr hdr;
2142 struct fill_search_info_args sargs, hargs;
2143 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
2144 struct dl_serpath *SLPpath, *hintpath;
2145 char *p;
2146 struct stat hint_stat;
2147 unsigned int SLPndx, hintndx, fndx, fcount;
2148 int fd;
2149 size_t flen;
2150 uint32_t dl;
2151 uint32_t magic; /* Magic number */
2152 uint32_t version; /* File version (1) */
2153 uint32_t strtab; /* Offset of string table in file */
2154 uint32_t dirlist; /* Offset of directory list in string table */
2155 uint32_t dirlistlen; /* strlen(dirlist) */
2156 bool is_le; /* Does the hints file use little endian */
2157 bool skip;
2158
2159 /* First call, read the hints file */
2160 if (hints == NULL) {
2161 /* Keep from trying again in case the hints file is bad. */
2162 hints = "";
2163
2164 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) ==
2165 -1) {
2166 dbg("failed to open hints file \"%s\"",
2167 ld_elf_hints_path);
2168 return (NULL);
2169 }
2170
2171 /*
2172 * Check of hdr.dirlistlen value against type limit
2173 * intends to pacify static analyzers. Further
2174 * paranoia leads to checks that dirlist is fully
2175 * contained in the file range.
2176 */
2177 if (read(fd, &hdr, sizeof hdr) != sizeof hdr) {
2178 dbg("failed to read %lu bytes from hints file \"%s\"",
2179 (u_long)sizeof hdr, ld_elf_hints_path);
2180 cleanup1:
2181 close(fd);
2182 hdr.dirlistlen = 0;
2183 return (NULL);
2184 }
2185 dbg("host byte-order: %s-endian",
2186 le32toh(1) == 1 ? "little" : "big");
2187 dbg("hints file byte-order: %s-endian",
2188 hdr.magic == htole32(ELFHINTS_MAGIC) ? "little" : "big");
2189 is_le = /*htole32(1) == 1 || */ hdr.magic ==
2190 htole32(ELFHINTS_MAGIC);
2191 magic = COND_SWAP(hdr.magic);
2192 version = COND_SWAP(hdr.version);
2193 strtab = COND_SWAP(hdr.strtab);
2194 dirlist = COND_SWAP(hdr.dirlist);
2195 dirlistlen = COND_SWAP(hdr.dirlistlen);
2196 if (magic != ELFHINTS_MAGIC) {
2197 dbg("invalid magic number %#08x (expected: %#08x)",
2198 magic, ELFHINTS_MAGIC);
2199 goto cleanup1;
2200 }
2201 if (version != 1) {
2202 dbg("hints file version %d (expected: 1)", version);
2203 goto cleanup1;
2204 }
2205 if (dirlistlen > UINT_MAX / 2) {
2206 dbg("directory list is to long: %d > %d", dirlistlen,
2207 UINT_MAX / 2);
2208 goto cleanup1;
2209 }
2210 if (fstat(fd, &hint_stat) == -1) {
2211 dbg("failed to find length of hints file \"%s\"",
2212 ld_elf_hints_path);
2213 goto cleanup1;
2214 }
2215 dl = strtab;
2216 if (dl + dirlist < dl) {
2217 dbg("invalid string table position %d", dl);
2218 goto cleanup1;
2219 }
2220 dl += dirlist;
2221 if (dl + dirlistlen < dl) {
2222 dbg("invalid directory list offset %d", dirlist);
2223 goto cleanup1;
2224 }
2225 dl += dirlistlen;
2226 if (dl > hint_stat.st_size) {
2227 dbg("hints file \"%s\" is truncated (%d vs. %jd bytes)",
2228 ld_elf_hints_path, dl,
2229 (uintmax_t)hint_stat.st_size);
2230 goto cleanup1;
2231 }
2232 p = xmalloc(dirlistlen + 1);
2233 if (pread(fd, p, dirlistlen + 1, strtab + dirlist) !=
2234 (ssize_t)dirlistlen + 1 || p[dirlistlen] != '\0') {
2235 free(p);
2236 dbg(
2237 "failed to read %d bytes starting at %d from hints file \"%s\"",
2238 dirlistlen + 1, strtab + dirlist,
2239 ld_elf_hints_path);
2240 goto cleanup1;
2241 }
2242 hints = p;
2243 close(fd);
2244 }
2245
2246 /*
2247 * If caller agreed to receive list which includes the default
2248 * paths, we are done. Otherwise, if we still did not
2249 * calculated filtered result, do it now.
2250 */
2251 if (!nostdlib)
2252 return (hints[0] != '\0' ? hints : NULL);
2253 if (filtered_path != NULL)
2254 goto filt_ret;
2255
2256 /*
2257 * Obtain the list of all configured search paths, and the
2258 * list of the default paths.
2259 *
2260 * First estimate the size of the results.
2261 */
2262 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
2263 smeta.dls_cnt = 0;
2264 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
2265 hmeta.dls_cnt = 0;
2266
2267 sargs.request = RTLD_DI_SERINFOSIZE;
2268 sargs.serinfo = &smeta;
2269 hargs.request = RTLD_DI_SERINFOSIZE;
2270 hargs.serinfo = &hmeta;
2271
2272 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
2273 &sargs);
2274 path_enumerate(hints, fill_search_info, NULL, &hargs);
2275
2276 SLPinfo = xmalloc(smeta.dls_size);
2277 hintinfo = xmalloc(hmeta.dls_size);
2278
2279 /*
2280 * Next fetch both sets of paths.
2281 */
2282 sargs.request = RTLD_DI_SERINFO;
2283 sargs.serinfo = SLPinfo;
2284 sargs.serpath = &SLPinfo->dls_serpath[0];
2285 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
2286
2287 hargs.request = RTLD_DI_SERINFO;
2288 hargs.serinfo = hintinfo;
2289 hargs.serpath = &hintinfo->dls_serpath[0];
2290 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
2291
2292 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
2293 &sargs);
2294 path_enumerate(hints, fill_search_info, NULL, &hargs);
2295
2296 /*
2297 * Now calculate the difference between two sets, by excluding
2298 * standard paths from the full set.
2299 */
2300 fndx = 0;
2301 fcount = 0;
2302 filtered_path = xmalloc(dirlistlen + 1);
2303 hintpath = &hintinfo->dls_serpath[0];
2304 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
2305 skip = false;
2306 SLPpath = &SLPinfo->dls_serpath[0];
2307 /*
2308 * Check each standard path against current.
2309 */
2310 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
2311 /* matched, skip the path */
2312 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
2313 skip = true;
2314 break;
2315 }
2316 }
2317 if (skip)
2318 continue;
2319 /*
2320 * Not matched against any standard path, add the path
2321 * to result. Separate consequtive paths with ':'.
2322 */
2323 if (fcount > 0) {
2324 filtered_path[fndx] = ':';
2325 fndx++;
2326 }
2327 fcount++;
2328 flen = strlen(hintpath->dls_name);
2329 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
2330 fndx += flen;
2331 }
2332 filtered_path[fndx] = '\0';
2333
2334 free(SLPinfo);
2335 free(hintinfo);
2336
2337 filt_ret:
2338 return (filtered_path[0] != '\0' ? filtered_path : NULL);
2339 }
2340
2341 static void
init_dag(Obj_Entry * root)2342 init_dag(Obj_Entry *root)
2343 {
2344 const Needed_Entry *needed;
2345 const Objlist_Entry *elm;
2346 DoneList donelist;
2347
2348 if (root->dag_inited)
2349 return;
2350 donelist_init(&donelist, NULL);
2351
2352 /* Root object belongs to own DAG. */
2353 objlist_push_tail(&root->dldags, root);
2354 objlist_push_tail(&root->dagmembers, root);
2355 donelist_check(&donelist, root);
2356
2357 /*
2358 * Add dependencies of root object to DAG in breadth order
2359 * by exploiting the fact that each new object get added
2360 * to the tail of the dagmembers list.
2361 */
2362 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2363 for (needed = elm->obj->needed; needed != NULL;
2364 needed = needed->next) {
2365 if (needed->obj == NULL ||
2366 donelist_check(&donelist, needed->obj))
2367 continue;
2368 objlist_push_tail(&needed->obj->dldags, root);
2369 objlist_push_tail(&root->dagmembers, needed->obj);
2370 }
2371 }
2372 root->dag_inited = true;
2373 donelist_free(&donelist);
2374 }
2375
2376 static void
init_marker(Obj_Entry * marker)2377 init_marker(Obj_Entry *marker)
2378 {
2379 bzero(marker, sizeof(*marker));
2380 marker->marker = true;
2381 }
2382
2383 Obj_Entry *
globallist_curr(const Obj_Entry * obj)2384 globallist_curr(const Obj_Entry *obj)
2385 {
2386 for (;;) {
2387 if (obj == NULL)
2388 return (NULL);
2389 if (!obj->marker)
2390 return (__DECONST(Obj_Entry *, obj));
2391 obj = TAILQ_PREV(obj, obj_entry_q, next);
2392 }
2393 }
2394
2395 Obj_Entry *
globallist_next(const Obj_Entry * obj)2396 globallist_next(const Obj_Entry *obj)
2397 {
2398 for (;;) {
2399 obj = TAILQ_NEXT(obj, next);
2400 if (obj == NULL)
2401 return (NULL);
2402 if (!obj->marker)
2403 return (__DECONST(Obj_Entry *, obj));
2404 }
2405 }
2406
2407 /* Prevent the object from being unmapped while the bind lock is dropped. */
2408 static void
hold_object(Obj_Entry * obj)2409 hold_object(Obj_Entry *obj)
2410 {
2411 obj->holdcount++;
2412 }
2413
2414 static void
unhold_object(Obj_Entry * obj)2415 unhold_object(Obj_Entry *obj)
2416 {
2417 assert(obj->holdcount > 0);
2418 if (--obj->holdcount == 0 && obj->unholdfree)
2419 release_object(obj);
2420 }
2421
2422 static void
process_z(Obj_Entry * root)2423 process_z(Obj_Entry *root)
2424 {
2425 const Objlist_Entry *elm;
2426 Obj_Entry *obj;
2427
2428 /*
2429 * Walk over object DAG and process every dependent object
2430 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need
2431 * to grow their own DAG.
2432 *
2433 * For DF_1_GLOBAL, DAG is required for symbol lookups in
2434 * symlook_global() to work.
2435 *
2436 * For DF_1_NODELETE, the DAG should have its reference upped.
2437 */
2438 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2439 obj = elm->obj;
2440 if (obj == NULL)
2441 continue;
2442 if (obj->z_nodelete && !obj->ref_nodel) {
2443 dbg("obj %s -z nodelete", obj->path);
2444 init_dag(obj);
2445 ref_dag(obj);
2446 obj->ref_nodel = true;
2447 }
2448 if (obj->z_global && objlist_find(&list_global, obj) == NULL) {
2449 dbg("obj %s -z global", obj->path);
2450 objlist_push_tail(&list_global, obj);
2451 init_dag(obj);
2452 }
2453 }
2454 }
2455
2456 static void
parse_rtld_phdr(Obj_Entry * obj)2457 parse_rtld_phdr(Obj_Entry *obj)
2458 {
2459 const Elf_Phdr *ph;
2460 Elf_Addr note_start, note_end;
2461 bool first_seg;
2462
2463 first_seg = true;
2464 obj->stack_flags = PF_X | PF_R | PF_W;
2465 for (ph = obj->phdr; ph < obj->phdr + obj->phnum; ph++) {
2466 switch (ph->p_type) {
2467 case PT_LOAD:
2468 if (first_seg) {
2469 obj->vaddrbase = rtld_trunc_page(ph->p_vaddr);
2470 first_seg = false;
2471 }
2472 obj->mapsize = rtld_round_page(ph->p_vaddr +
2473 ph->p_memsz) - obj->vaddrbase;
2474 break;
2475 case PT_GNU_STACK:
2476 obj->stack_flags = ph->p_flags;
2477 break;
2478 case PT_NOTE:
2479 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
2480 note_end = note_start + ph->p_filesz;
2481 digest_notes(obj, note_start, note_end);
2482 break;
2483 }
2484 }
2485 }
2486
2487 /*
2488 * Initialize the dynamic linker. The argument is the address at which
2489 * the dynamic linker has been mapped into memory. The primary task of
2490 * this function is to relocate the dynamic linker.
2491 */
2492 static void
init_rtld(caddr_t mapbase,Elf_Auxinfo ** aux_info)2493 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
2494 {
2495 Obj_Entry objtmp; /* Temporary rtld object */
2496 const Elf_Ehdr *ehdr;
2497 const Elf_Dyn *dyn_rpath;
2498 const Elf_Dyn *dyn_soname;
2499 const Elf_Dyn *dyn_runpath;
2500
2501 /*
2502 * Conjure up an Obj_Entry structure for the dynamic linker.
2503 *
2504 * The "path" member can't be initialized yet because string constants
2505 * cannot yet be accessed. Below we will set it correctly.
2506 */
2507 memset(&objtmp, 0, sizeof(objtmp));
2508 objtmp.path = NULL;
2509 objtmp.rtld = true;
2510 objtmp.mapbase = mapbase;
2511 objtmp.relocbase = mapbase;
2512
2513 objtmp.dynamic = rtld_dynamic(&objtmp);
2514 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
2515 assert(objtmp.needed == NULL);
2516 assert(!objtmp.textrel);
2517 /*
2518 * Temporarily put the dynamic linker entry into the object list, so
2519 * that symbols can be found.
2520 */
2521 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
2522
2523 ehdr = (Elf_Ehdr *)mapbase;
2524 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff);
2525 objtmp.phnum = ehdr->e_phnum;
2526
2527 /* Initialize the object list. */
2528 TAILQ_INIT(&obj_list);
2529
2530 /* Now that non-local variables can be accesses, copy out obj_rtld. */
2531 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
2532
2533 /* The page size is required by the dynamic memory allocator. */
2534 init_pagesizes(aux_info);
2535
2536 if (aux_info[AT_OSRELDATE] != NULL)
2537 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
2538
2539 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
2540
2541 /* Replace the path with a dynamically allocated copy. */
2542 obj_rtld.path = xstrdup(ld_path_rtld);
2543
2544 parse_rtld_phdr(&obj_rtld);
2545 if (obj_enforce_relro(&obj_rtld) == -1)
2546 rtld_die();
2547
2548 r_debug.r_version = R_DEBUG_VERSION;
2549 r_debug.r_brk = r_debug_state;
2550 r_debug.r_state = RT_CONSISTENT;
2551 r_debug.r_ldbase = obj_rtld.relocbase;
2552 }
2553
2554 /*
2555 * Retrieve the array of supported page sizes. The kernel provides the page
2556 * sizes in increasing order.
2557 */
2558 static void
init_pagesizes(Elf_Auxinfo ** aux_info)2559 init_pagesizes(Elf_Auxinfo **aux_info)
2560 {
2561 static size_t psa[MAXPAGESIZES];
2562 int mib[2];
2563 size_t len, size;
2564
2565 if (aux_info[AT_PAGESIZES] != NULL &&
2566 aux_info[AT_PAGESIZESLEN] != NULL) {
2567 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val;
2568 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr;
2569 } else {
2570 len = 2;
2571 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0)
2572 size = sizeof(psa);
2573 else {
2574 /* As a fallback, retrieve the base page size. */
2575 size = sizeof(psa[0]);
2576 if (aux_info[AT_PAGESZ] != NULL) {
2577 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val;
2578 goto psa_filled;
2579 } else {
2580 mib[0] = CTL_HW;
2581 mib[1] = HW_PAGESIZE;
2582 len = 2;
2583 }
2584 }
2585 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) {
2586 _rtld_error("sysctl for hw.pagesize(s) failed");
2587 rtld_die();
2588 }
2589 psa_filled:
2590 pagesizes = psa;
2591 }
2592 npagesizes = size / sizeof(pagesizes[0]);
2593 /* Discard any invalid entries at the end of the array. */
2594 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0)
2595 npagesizes--;
2596
2597 page_size = pagesizes[0];
2598 }
2599
2600 /*
2601 * Add the init functions from a needed object list (and its recursive
2602 * needed objects) to "list". This is not used directly; it is a helper
2603 * function for initlist_add_objects(). The write lock must be held
2604 * when this function is called.
2605 */
2606 static void
initlist_add_neededs(Needed_Entry * needed,Objlist * list,Objlist * iflist)2607 initlist_add_neededs(Needed_Entry *needed, Objlist *list, Objlist *iflist)
2608 {
2609 /* Recursively process the successor needed objects. */
2610 if (needed->next != NULL)
2611 initlist_add_neededs(needed->next, list, iflist);
2612
2613 /* Process the current needed object. */
2614 if (needed->obj != NULL)
2615 initlist_add_objects(needed->obj, needed->obj, list, iflist);
2616 }
2617
2618 /*
2619 * Scan all of the DAGs rooted in the range of objects from "obj" to
2620 * "tail" and add their init functions to "list". This recurses over
2621 * the DAGs and ensure the proper init ordering such that each object's
2622 * needed libraries are initialized before the object itself. At the
2623 * same time, this function adds the objects to the global finalization
2624 * list "list_fini" in the opposite order. The write lock must be
2625 * held when this function is called.
2626 */
2627 static void
initlist_for_loaded_obj(Obj_Entry * obj,Obj_Entry * tail,Objlist * list)2628 initlist_for_loaded_obj(Obj_Entry *obj, Obj_Entry *tail, Objlist *list)
2629 {
2630 Objlist iflist; /* initfirst objs and their needed */
2631 Objlist_Entry *tmp;
2632
2633 objlist_init(&iflist);
2634 initlist_add_objects(obj, tail, list, &iflist);
2635
2636 STAILQ_FOREACH(tmp, &iflist, link) {
2637 Obj_Entry *tobj = tmp->obj;
2638
2639 if ((tobj->fini != 0 || tobj->fini_array != NULL) &&
2640 !tobj->on_fini_list) {
2641 objlist_push_tail(&list_fini, tobj);
2642 tobj->on_fini_list = true;
2643 }
2644 }
2645
2646 /*
2647 * This might result in the same object appearing more
2648 * than once on the init list. objlist_call_init()
2649 * uses obj->init_scanned to avoid dup calls.
2650 */
2651 STAILQ_REVERSE(&iflist, Struct_Objlist_Entry, link);
2652 STAILQ_FOREACH(tmp, &iflist, link)
2653 objlist_push_head(list, tmp->obj);
2654
2655 objlist_clear(&iflist);
2656 }
2657
2658 static void
initlist_add_objects(Obj_Entry * obj,Obj_Entry * tail,Objlist * list,Objlist * iflist)2659 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list,
2660 Objlist *iflist)
2661 {
2662 Obj_Entry *nobj;
2663
2664 if (obj->init_done)
2665 return;
2666
2667 if (obj->z_initfirst || list == NULL) {
2668 /*
2669 * Ignore obj->init_scanned. The object might indeed
2670 * already be on the init list, but due to being
2671 * needed by an initfirst object, we must put it at
2672 * the head of the init list. obj->init_done protects
2673 * against double-initialization.
2674 */
2675 if (obj->needed != NULL)
2676 initlist_add_neededs(obj->needed, NULL, iflist);
2677 if (obj->needed_filtees != NULL)
2678 initlist_add_neededs(obj->needed_filtees, NULL,
2679 iflist);
2680 if (obj->needed_aux_filtees != NULL)
2681 initlist_add_neededs(obj->needed_aux_filtees,
2682 NULL, iflist);
2683 objlist_push_tail(iflist, obj);
2684
2685 /* Recursively process the successor objects. */
2686 nobj = globallist_next(obj);
2687 if (nobj != NULL && obj != tail)
2688 initlist_add_objects(nobj, tail, list, iflist);
2689 } else {
2690 if (obj->init_scanned)
2691 return;
2692 obj->init_scanned = true;
2693
2694 /* Recursively process the successor objects. */
2695 nobj = globallist_next(obj);
2696 if (nobj != NULL && obj != tail)
2697 initlist_add_objects(nobj, tail, list, iflist);
2698
2699 /* Recursively process the needed objects. */
2700 if (obj->needed != NULL)
2701 initlist_add_neededs(obj->needed, list, iflist);
2702 if (obj->needed_filtees != NULL)
2703 initlist_add_neededs(obj->needed_filtees, list,
2704 iflist);
2705 if (obj->needed_aux_filtees != NULL)
2706 initlist_add_neededs(obj->needed_aux_filtees, list,
2707 iflist);
2708
2709 /* Add the object to the init list. */
2710 objlist_push_tail(list, obj);
2711
2712 /*
2713 * Add the object to the global fini list in the
2714 * reverse order.
2715 */
2716 if ((obj->fini != 0 || obj->fini_array != NULL) &&
2717 !obj->on_fini_list) {
2718 objlist_push_head(&list_fini, obj);
2719 obj->on_fini_list = true;
2720 }
2721 }
2722 }
2723
2724 static void
free_needed_filtees(Needed_Entry * n,RtldLockState * lockstate)2725 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate)
2726 {
2727 Needed_Entry *needed, *needed1;
2728
2729 for (needed = n; needed != NULL; needed = needed->next) {
2730 if (needed->obj != NULL) {
2731 dlclose_locked(needed->obj, lockstate);
2732 needed->obj = NULL;
2733 }
2734 }
2735 for (needed = n; needed != NULL; needed = needed1) {
2736 needed1 = needed->next;
2737 free(needed);
2738 }
2739 }
2740
2741 static void
unload_filtees(Obj_Entry * obj,RtldLockState * lockstate)2742 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate)
2743 {
2744 free_needed_filtees(obj->needed_filtees, lockstate);
2745 obj->needed_filtees = NULL;
2746 free_needed_filtees(obj->needed_aux_filtees, lockstate);
2747 obj->needed_aux_filtees = NULL;
2748 obj->filtees_loaded = false;
2749 }
2750
2751 static void
load_filtee1(Obj_Entry * obj,Needed_Entry * needed,int flags,RtldLockState * lockstate)2752 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
2753 RtldLockState *lockstate)
2754 {
2755 for (; needed != NULL; needed = needed->next) {
2756 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
2757 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW :
2758 RTLD_LAZY) | RTLD_LOCAL, lockstate);
2759 }
2760 }
2761
2762 static void
load_filtees(Obj_Entry * obj,int flags,RtldLockState * lockstate)2763 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
2764 {
2765 if (obj->filtees_loaded || obj->filtees_loading)
2766 return;
2767 lock_restart_for_upgrade(lockstate);
2768 obj->filtees_loading = true;
2769 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
2770 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
2771 obj->filtees_loaded = true;
2772 obj->filtees_loading = false;
2773 }
2774
2775 static int
process_needed(Obj_Entry * obj,Needed_Entry * needed,int flags)2776 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
2777 {
2778 Obj_Entry *obj1;
2779
2780 for (; needed != NULL; needed = needed->next) {
2781 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1,
2782 obj, flags & ~RTLD_LO_NOLOAD);
2783 if (obj1 == NULL && !ld_tracing &&
2784 (flags & RTLD_LO_FILTEES) == 0)
2785 return (-1);
2786 }
2787 return (0);
2788 }
2789
2790 /*
2791 * Given a shared object, traverse its list of needed objects, and load
2792 * each of them. Returns 0 on success. Generates an error message and
2793 * returns -1 on failure.
2794 */
2795 static int
load_needed_objects(Obj_Entry * first,int flags)2796 load_needed_objects(Obj_Entry *first, int flags)
2797 {
2798 Obj_Entry *obj;
2799
2800 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
2801 if (obj->marker)
2802 continue;
2803 if (process_needed(obj, obj->needed, flags) == -1)
2804 return (-1);
2805 }
2806 return (0);
2807 }
2808
2809 static int
load_preload_objects(const char * penv,bool isfd)2810 load_preload_objects(const char *penv, bool isfd)
2811 {
2812 Obj_Entry *obj;
2813 const char *name;
2814 size_t len;
2815 char savech, *p, *psave;
2816 int fd;
2817 static const char delim[] = " \t:;";
2818
2819 if (penv == NULL)
2820 return (0);
2821
2822 p = psave = xstrdup(penv);
2823 p += strspn(p, delim);
2824 while (*p != '\0') {
2825 len = strcspn(p, delim);
2826
2827 savech = p[len];
2828 p[len] = '\0';
2829 if (isfd) {
2830 name = NULL;
2831 fd = parse_integer(p);
2832 if (fd == -1) {
2833 free(psave);
2834 return (-1);
2835 }
2836 } else {
2837 name = p;
2838 fd = -1;
2839 }
2840
2841 obj = load_object(name, fd, NULL, 0);
2842 if (obj == NULL) {
2843 free(psave);
2844 return (-1); /* XXX - cleanup */
2845 }
2846 obj->z_interpose = true;
2847 p[len] = savech;
2848 p += len;
2849 p += strspn(p, delim);
2850 }
2851 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2852
2853 free(psave);
2854 return (0);
2855 }
2856
2857 static const char *
printable_path(const char * path)2858 printable_path(const char *path)
2859 {
2860 return (path == NULL ? "<unknown>" : path);
2861 }
2862
2863 /*
2864 * Load a shared object into memory, if it is not already loaded. The
2865 * object may be specified by name or by user-supplied file descriptor
2866 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2867 * duplicate is.
2868 *
2869 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2870 * on failure.
2871 */
2872 static Obj_Entry *
load_object(const char * name,int fd_u,const Obj_Entry * refobj,int flags)2873 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2874 {
2875 Obj_Entry *obj;
2876 int fd;
2877 struct stat sb;
2878 char *path;
2879
2880 fd = -1;
2881 if (name != NULL) {
2882 TAILQ_FOREACH(obj, &obj_list, next) {
2883 if (obj->marker || obj->doomed)
2884 continue;
2885 if (object_match_name(obj, name))
2886 return (obj);
2887 }
2888
2889 path = find_library(name, refobj, &fd);
2890 if (path == NULL)
2891 return (NULL);
2892 } else
2893 path = NULL;
2894
2895 if (fd >= 0) {
2896 /*
2897 * search_library_pathfds() opens a fresh file descriptor for
2898 * the library, so there is no need to dup().
2899 */
2900 } else if (fd_u == -1) {
2901 /*
2902 * If we didn't find a match by pathname, or the name is not
2903 * supplied, open the file and check again by device and inode.
2904 * This avoids false mismatches caused by multiple links or ".."
2905 * in pathnames.
2906 *
2907 * To avoid a race, we open the file and use fstat() rather than
2908 * using stat().
2909 */
2910 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) {
2911 fd = try_fds_open(path, ld_library_dirs);
2912 if (fd == -1) {
2913 _rtld_error("Cannot open \"%s\"", path);
2914 free(path);
2915 return (NULL);
2916 }
2917 }
2918 } else {
2919 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0);
2920 if (fd == -1) {
2921 _rtld_error("Cannot dup fd");
2922 free(path);
2923 return (NULL);
2924 }
2925 }
2926 if (fstat(fd, &sb) == -1) {
2927 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2928 close(fd);
2929 free(path);
2930 return (NULL);
2931 }
2932 TAILQ_FOREACH(obj, &obj_list, next) {
2933 if (obj->marker || obj->doomed)
2934 continue;
2935 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2936 break;
2937 }
2938 if (obj != NULL) {
2939 if (name != NULL)
2940 object_add_name(obj, name);
2941 free(path);
2942 close(fd);
2943 return (obj);
2944 }
2945 if (flags & RTLD_LO_NOLOAD) {
2946 free(path);
2947 close(fd);
2948 return (NULL);
2949 }
2950
2951 /* First use of this object, so we must map it in */
2952 obj = do_load_object(fd, name, path, &sb, flags);
2953 if (obj == NULL)
2954 free(path);
2955 close(fd);
2956
2957 return (obj);
2958 }
2959
2960 static Obj_Entry *
do_load_object(int fd,const char * name,char * path,struct stat * sbp,int flags)2961 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2962 int flags)
2963 {
2964 Obj_Entry *obj;
2965 struct statfs fs;
2966
2967 /*
2968 * First, make sure that environment variables haven't been
2969 * used to circumvent the noexec flag on a filesystem.
2970 * We ignore fstatfs(2) failures, since fd might reference
2971 * not a file, e.g. shmfd.
2972 */
2973 if (dangerous_ld_env && fstatfs(fd, &fs) == 0 &&
2974 (fs.f_flags & MNT_NOEXEC) != 0) {
2975 _rtld_error("Cannot execute objects on %s", fs.f_mntonname);
2976 return (NULL);
2977 }
2978
2979 dbg("loading \"%s\"", printable_path(path));
2980 obj = map_object(fd, printable_path(path), sbp, false);
2981 if (obj == NULL)
2982 return (NULL);
2983
2984 /*
2985 * If DT_SONAME is present in the object, digest_dynamic2 already
2986 * added it to the object names.
2987 */
2988 if (name != NULL)
2989 object_add_name(obj, name);
2990 obj->path = path;
2991 if (!digest_dynamic(obj, 0))
2992 goto errp;
2993 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2994 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2995 if (obj->z_pie && (flags & RTLD_LO_TRACE) == 0) {
2996 dbg("refusing to load PIE executable \"%s\"", obj->path);
2997 _rtld_error("Cannot load PIE binary %s as DSO", obj->path);
2998 goto errp;
2999 }
3000 if (obj->z_noopen &&
3001 (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == RTLD_LO_DLOPEN) {
3002 dbg("refusing to load non-loadable \"%s\"", obj->path);
3003 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
3004 goto errp;
3005 }
3006
3007 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0;
3008 TAILQ_INSERT_TAIL(&obj_list, obj, next);
3009 obj_count++;
3010 obj_loads++;
3011 linkmap_add(obj); /* for GDB & dlinfo() */
3012 max_stack_flags |= obj->stack_flags;
3013
3014 dbg(" %p .. %p: %s", obj->mapbase, obj->mapbase + obj->mapsize - 1,
3015 obj->path);
3016 if (obj->textrel)
3017 dbg(" WARNING: %s has impure text", obj->path);
3018 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
3019 obj->path);
3020
3021 return (obj);
3022
3023 errp:
3024 munmap(obj->mapbase, obj->mapsize);
3025 obj_free(obj);
3026 return (NULL);
3027 }
3028
3029 static int
load_kpreload(const void * addr)3030 load_kpreload(const void *addr)
3031 {
3032 Obj_Entry *obj;
3033 const Elf_Ehdr *ehdr;
3034 const Elf_Phdr *phdr, *phlimit, *phdyn, *seg0, *segn;
3035 static const char kname[] = "[vdso]";
3036
3037 ehdr = addr;
3038 if (!check_elf_headers(ehdr, "kpreload"))
3039 return (-1);
3040 obj = obj_new();
3041 phdr = (const Elf_Phdr *)((const char *)addr + ehdr->e_phoff);
3042 obj->phdr = phdr;
3043 obj->phnum = ehdr->e_phnum;
3044 phlimit = phdr + ehdr->e_phnum;
3045 seg0 = segn = NULL;
3046
3047 for (; phdr < phlimit; phdr++) {
3048 switch (phdr->p_type) {
3049 case PT_DYNAMIC:
3050 phdyn = phdr;
3051 break;
3052 case PT_GNU_STACK:
3053 /* Absense of PT_GNU_STACK implies stack_flags == 0. */
3054 obj->stack_flags = phdr->p_flags;
3055 break;
3056 case PT_LOAD:
3057 if (seg0 == NULL || seg0->p_vaddr > phdr->p_vaddr)
3058 seg0 = phdr;
3059 if (segn == NULL ||
3060 segn->p_vaddr + segn->p_memsz <
3061 phdr->p_vaddr + phdr->p_memsz)
3062 segn = phdr;
3063 break;
3064 }
3065 }
3066
3067 obj->mapbase = __DECONST(caddr_t, addr);
3068 obj->mapsize = segn->p_vaddr + segn->p_memsz;
3069 obj->vaddrbase = 0;
3070 obj->relocbase = obj->mapbase;
3071
3072 object_add_name(obj, kname);
3073 obj->path = xstrdup(kname);
3074 obj->dynamic = (const Elf_Dyn *)(obj->relocbase + phdyn->p_vaddr);
3075
3076 if (!digest_dynamic(obj, 0)) {
3077 obj_free(obj);
3078 return (-1);
3079 }
3080
3081 /*
3082 * We assume that kernel-preloaded object does not need
3083 * relocation. It is currently written into read-only page,
3084 * handling relocations would mean we need to allocate at
3085 * least one additional page per AS.
3086 */
3087 dbg("%s mapbase %p phdrs %p PT_LOAD phdr %p vaddr %p dynamic %p",
3088 obj->path, obj->mapbase, obj->phdr, seg0,
3089 obj->relocbase + seg0->p_vaddr, obj->dynamic);
3090
3091 TAILQ_INSERT_TAIL(&obj_list, obj, next);
3092 obj_count++;
3093 obj_loads++;
3094 linkmap_add(obj); /* for GDB & dlinfo() */
3095 max_stack_flags |= obj->stack_flags;
3096
3097 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
3098 obj->path);
3099 return (0);
3100 }
3101
3102 Obj_Entry *
obj_from_addr(const void * addr)3103 obj_from_addr(const void *addr)
3104 {
3105 Obj_Entry *obj;
3106
3107 TAILQ_FOREACH(obj, &obj_list, next) {
3108 if (obj->marker)
3109 continue;
3110 if (addr < (void *)obj->mapbase)
3111 continue;
3112 if (addr < (void *)(obj->mapbase + obj->mapsize))
3113 return obj;
3114 }
3115 return (NULL);
3116 }
3117
3118 static void
preinit_main(void)3119 preinit_main(void)
3120 {
3121 uintptr_t *preinit_addr;
3122 int index;
3123
3124 preinit_addr = obj_main->preinit_array;
3125 if (preinit_addr == NULL)
3126 return;
3127
3128 for (index = 0; index < obj_main->preinit_array_num; index++) {
3129 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
3130 dbg("calling preinit function for %s at %p",
3131 obj_main->path, (void *)preinit_addr[index]);
3132 LD_UTRACE(UTRACE_INIT_CALL, obj_main,
3133 (void *)preinit_addr[index], 0, 0, obj_main->path);
3134 call_init_pointer(obj_main, preinit_addr[index]);
3135 }
3136 }
3137 }
3138
3139 /*
3140 * Call the finalization functions for each of the objects in "list"
3141 * belonging to the DAG of "root" and referenced once. If NULL "root"
3142 * is specified, every finalization function will be called regardless
3143 * of the reference count and the list elements won't be freed. All of
3144 * the objects are expected to have non-NULL fini functions.
3145 */
3146 static void
objlist_call_fini(Objlist * list,Obj_Entry * root,RtldLockState * lockstate)3147 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
3148 {
3149 Objlist_Entry *elm;
3150 struct dlerror_save *saved_msg;
3151 uintptr_t *fini_addr;
3152 int index;
3153
3154 assert(root == NULL || root->refcount == 1);
3155
3156 if (root != NULL)
3157 root->doomed = true;
3158
3159 /*
3160 * Preserve the current error message since a fini function might
3161 * call into the dynamic linker and overwrite it.
3162 */
3163 saved_msg = errmsg_save();
3164 do {
3165 STAILQ_FOREACH(elm, list, link) {
3166 if (root != NULL &&
3167 (elm->obj->refcount != 1 ||
3168 objlist_find(&root->dagmembers, elm->obj) ==
3169 NULL))
3170 continue;
3171 /* Remove object from fini list to prevent recursive
3172 * invocation. */
3173 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
3174 /* Ensure that new references cannot be acquired. */
3175 elm->obj->doomed = true;
3176
3177 hold_object(elm->obj);
3178 lock_release(rtld_bind_lock, lockstate);
3179 /*
3180 * It is legal to have both DT_FINI and DT_FINI_ARRAY
3181 * defined. When this happens, DT_FINI_ARRAY is
3182 * processed first.
3183 */
3184 fini_addr = elm->obj->fini_array;
3185 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
3186 for (index = elm->obj->fini_array_num - 1;
3187 index >= 0; index--) {
3188 if (fini_addr[index] != 0 &&
3189 fini_addr[index] != 1 &&
3190 fini_addr[index] != (Elf_Addr)-1) {
3191 dbg("calling fini function for %s at %p",
3192 elm->obj->path,
3193 (void *)fini_addr[index]);
3194 LD_UTRACE(UTRACE_FINI_CALL,
3195 elm->obj,
3196 (void *)fini_addr[index], 0,
3197 0, elm->obj->path);
3198 call_initfini_pointer(elm->obj,
3199 fini_addr[index]);
3200 }
3201 }
3202 }
3203 if (elm->obj->fini != 0) {
3204 dbg("calling fini function for %s at %p",
3205 elm->obj->path, (void *)elm->obj->fini);
3206 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
3207 (void *)elm->obj->fini, 0, 0,
3208 elm->obj->path);
3209 call_initfini_pointer(elm->obj, elm->obj->fini);
3210 }
3211 wlock_acquire(rtld_bind_lock, lockstate);
3212 unhold_object(elm->obj);
3213 /* No need to free anything if process is going down. */
3214 if (root != NULL)
3215 free(elm);
3216 /*
3217 * We must restart the list traversal after every fini
3218 * call because a dlclose() call from the fini function
3219 * or from another thread might have modified the
3220 * reference counts.
3221 */
3222 break;
3223 }
3224 } while (elm != NULL);
3225 errmsg_restore(saved_msg);
3226 }
3227
3228 /*
3229 * Call the initialization functions for each of the objects in
3230 * "list". All of the objects are expected to have non-NULL init
3231 * functions.
3232 */
3233 static void
objlist_call_init(Objlist * list,RtldLockState * lockstate)3234 objlist_call_init(Objlist *list, RtldLockState *lockstate)
3235 {
3236 Objlist_Entry *elm;
3237 Obj_Entry *obj;
3238 struct dlerror_save *saved_msg;
3239 uintptr_t *init_addr;
3240 void (*reg)(void (*)(void));
3241 int index;
3242
3243 /*
3244 * Clean init_scanned flag so that objects can be rechecked and
3245 * possibly initialized earlier if any of vectors called below
3246 * cause the change by using dlopen.
3247 */
3248 TAILQ_FOREACH(obj, &obj_list, next) {
3249 if (obj->marker)
3250 continue;
3251 obj->init_scanned = false;
3252 }
3253
3254 /*
3255 * Preserve the current error message since an init function might
3256 * call into the dynamic linker and overwrite it.
3257 */
3258 saved_msg = errmsg_save();
3259 STAILQ_FOREACH(elm, list, link) {
3260 if (elm->obj->init_done) /* Initialized early. */
3261 continue;
3262 /*
3263 * Race: other thread might try to use this object before
3264 * current one completes the initialization. Not much can be
3265 * done here without better locking.
3266 */
3267 elm->obj->init_done = true;
3268 hold_object(elm->obj);
3269 reg = NULL;
3270 if (elm->obj == obj_main && obj_main->crt_no_init) {
3271 reg = (void (*)(void (*)(void)))
3272 get_program_var_addr("__libc_atexit", lockstate);
3273 }
3274 lock_release(rtld_bind_lock, lockstate);
3275 if (reg != NULL) {
3276 reg(rtld_exit);
3277 rtld_exit_ptr = rtld_nop_exit;
3278 }
3279
3280 /*
3281 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
3282 * When this happens, DT_INIT is processed first.
3283 */
3284 if (elm->obj->init != 0) {
3285 dbg("calling init function for %s at %p",
3286 elm->obj->path, (void *)elm->obj->init);
3287 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
3288 (void *)elm->obj->init, 0, 0, elm->obj->path);
3289 call_init_pointer(elm->obj, elm->obj->init);
3290 }
3291 init_addr = elm->obj->init_array;
3292 if (init_addr != NULL) {
3293 for (index = 0; index < elm->obj->init_array_num;
3294 index++) {
3295 if (init_addr[index] != 0 &&
3296 init_addr[index] != 1 &&
3297 init_addr[index] != (Elf_Addr)-1) {
3298 dbg("calling init function for %s at %p",
3299 elm->obj->path,
3300 (void *)init_addr[index]);
3301 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
3302 (void *)init_addr[index], 0, 0,
3303 elm->obj->path);
3304 call_init_pointer(elm->obj,
3305 init_addr[index]);
3306 }
3307 }
3308 }
3309 wlock_acquire(rtld_bind_lock, lockstate);
3310 unhold_object(elm->obj);
3311 }
3312 errmsg_restore(saved_msg);
3313 }
3314
3315 static void
objlist_clear(Objlist * list)3316 objlist_clear(Objlist *list)
3317 {
3318 Objlist_Entry *elm;
3319
3320 while (!STAILQ_EMPTY(list)) {
3321 elm = STAILQ_FIRST(list);
3322 STAILQ_REMOVE_HEAD(list, link);
3323 free(elm);
3324 }
3325 }
3326
3327 static Objlist_Entry *
objlist_find(Objlist * list,const Obj_Entry * obj)3328 objlist_find(Objlist *list, const Obj_Entry *obj)
3329 {
3330 Objlist_Entry *elm;
3331
3332 STAILQ_FOREACH(elm, list, link)
3333 if (elm->obj == obj)
3334 return elm;
3335 return (NULL);
3336 }
3337
3338 static void
objlist_init(Objlist * list)3339 objlist_init(Objlist *list)
3340 {
3341 STAILQ_INIT(list);
3342 }
3343
3344 static void
objlist_push_head(Objlist * list,Obj_Entry * obj)3345 objlist_push_head(Objlist *list, Obj_Entry *obj)
3346 {
3347 Objlist_Entry *elm;
3348
3349 elm = NEW(Objlist_Entry);
3350 elm->obj = obj;
3351 STAILQ_INSERT_HEAD(list, elm, link);
3352 }
3353
3354 static void
objlist_push_tail(Objlist * list,Obj_Entry * obj)3355 objlist_push_tail(Objlist *list, Obj_Entry *obj)
3356 {
3357 Objlist_Entry *elm;
3358
3359 elm = NEW(Objlist_Entry);
3360 elm->obj = obj;
3361 STAILQ_INSERT_TAIL(list, elm, link);
3362 }
3363
3364 static void
objlist_put_after(Objlist * list,Obj_Entry * listobj,Obj_Entry * obj)3365 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj)
3366 {
3367 Objlist_Entry *elm, *listelm;
3368
3369 STAILQ_FOREACH(listelm, list, link) {
3370 if (listelm->obj == listobj)
3371 break;
3372 }
3373 elm = NEW(Objlist_Entry);
3374 elm->obj = obj;
3375 if (listelm != NULL)
3376 STAILQ_INSERT_AFTER(list, listelm, elm, link);
3377 else
3378 STAILQ_INSERT_TAIL(list, elm, link);
3379 }
3380
3381 static void
objlist_remove(Objlist * list,Obj_Entry * obj)3382 objlist_remove(Objlist *list, Obj_Entry *obj)
3383 {
3384 Objlist_Entry *elm;
3385
3386 if ((elm = objlist_find(list, obj)) != NULL) {
3387 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
3388 free(elm);
3389 }
3390 }
3391
3392 /*
3393 * Relocate dag rooted in the specified object.
3394 * Returns 0 on success, or -1 on failure.
3395 */
3396
3397 static int
relocate_object_dag(Obj_Entry * root,bool bind_now,Obj_Entry * rtldobj,int flags,RtldLockState * lockstate)3398 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
3399 int flags, RtldLockState *lockstate)
3400 {
3401 Objlist_Entry *elm;
3402 int error;
3403
3404 error = 0;
3405 STAILQ_FOREACH(elm, &root->dagmembers, link) {
3406 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
3407 lockstate);
3408 if (error == -1)
3409 break;
3410 }
3411 return (error);
3412 }
3413
3414 /*
3415 * Prepare for, or clean after, relocating an object marked with
3416 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only
3417 * segments are remapped read-write. After relocations are done, the
3418 * segment's permissions are returned back to the modes specified in
3419 * the phdrs. If any relocation happened, or always for wired
3420 * program, COW is triggered.
3421 */
3422 static int
reloc_textrel_prot(Obj_Entry * obj,bool before)3423 reloc_textrel_prot(Obj_Entry *obj, bool before)
3424 {
3425 const Elf_Phdr *ph;
3426 void *base;
3427 size_t sz;
3428 int prot;
3429
3430 for (ph = obj->phdr; ph < obj->phdr + obj->phnum; ph++) {
3431 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0)
3432 continue;
3433 base = obj->relocbase + rtld_trunc_page(ph->p_vaddr);
3434 sz = rtld_round_page(ph->p_vaddr + ph->p_filesz) -
3435 rtld_trunc_page(ph->p_vaddr);
3436 prot = before ? (PROT_READ | PROT_WRITE) :
3437 convert_prot(ph->p_flags);
3438 if (mprotect(base, sz, prot) == -1) {
3439 _rtld_error("%s: Cannot write-%sable text segment: %s",
3440 obj->path, before ? "en" : "dis",
3441 rtld_strerror(errno));
3442 return (-1);
3443 }
3444 }
3445 return (0);
3446 }
3447
3448 /* Process RELR relative relocations. */
3449 static void
reloc_relr(Obj_Entry * obj)3450 reloc_relr(Obj_Entry *obj)
3451 {
3452 const Elf_Relr *relr, *relrlim;
3453 Elf_Addr *where;
3454
3455 relrlim = (const Elf_Relr *)((const char *)obj->relr + obj->relrsize);
3456 for (relr = obj->relr; relr < relrlim; relr++) {
3457 Elf_Relr entry = *relr;
3458
3459 if ((entry & 1) == 0) {
3460 where = (Elf_Addr *)(obj->relocbase + entry);
3461 *where++ += (Elf_Addr)obj->relocbase;
3462 } else {
3463 for (long i = 0; (entry >>= 1) != 0; i++)
3464 if ((entry & 1) != 0)
3465 where[i] += (Elf_Addr)obj->relocbase;
3466 where += CHAR_BIT * sizeof(Elf_Relr) - 1;
3467 }
3468 }
3469 }
3470
3471 /*
3472 * Relocate single object.
3473 * Returns 0 on success, or -1 on failure.
3474 */
3475 static int
relocate_object(Obj_Entry * obj,bool bind_now,Obj_Entry * rtldobj,int flags,RtldLockState * lockstate)3476 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, int flags,
3477 RtldLockState *lockstate)
3478 {
3479 if (obj->relocated)
3480 return (0);
3481 obj->relocated = true;
3482 if (obj != rtldobj)
3483 dbg("relocating \"%s\"", obj->path);
3484
3485 if (obj->symtab == NULL || obj->strtab == NULL ||
3486 !(obj->valid_hash_sysv || obj->valid_hash_gnu))
3487 dbg("object %s has no run-time symbol table", obj->path);
3488
3489 /* There are relocations to the write-protected text segment. */
3490 if (obj->textrel && reloc_textrel_prot(obj, true) != 0)
3491 return (-1);
3492
3493 /* Process the non-PLT non-IFUNC relocations. */
3494 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
3495 return (-1);
3496 reloc_relr(obj);
3497
3498 /* Re-protected the text segment. */
3499 if (obj->textrel && reloc_textrel_prot(obj, false) != 0)
3500 return (-1);
3501
3502 /* Set the special PLT or GOT entries. */
3503 init_pltgot(obj);
3504
3505 /* Process the PLT relocations. */
3506 if (reloc_plt(obj, flags, lockstate) == -1)
3507 return (-1);
3508 /* Relocate the jump slots if we are doing immediate binding. */
3509 if ((obj->bind_now || bind_now) &&
3510 reloc_jmpslots(obj, flags, lockstate) == -1)
3511 return (-1);
3512
3513 if (obj != rtldobj && !obj->mainprog && obj_enforce_relro(obj) == -1)
3514 return (-1);
3515
3516 /*
3517 * Set up the magic number and version in the Obj_Entry. These
3518 * were checked in the crt1.o from the original ElfKit, so we
3519 * set them for backward compatibility.
3520 */
3521 obj->magic = RTLD_MAGIC;
3522 obj->version = RTLD_VERSION;
3523
3524 return (0);
3525 }
3526
3527 /*
3528 * Relocate newly-loaded shared objects. The argument is a pointer to
3529 * the Obj_Entry for the first such object. All objects from the first
3530 * to the end of the list of objects are relocated. Returns 0 on success,
3531 * or -1 on failure.
3532 */
3533 static int
relocate_objects(Obj_Entry * first,bool bind_now,Obj_Entry * rtldobj,int flags,RtldLockState * lockstate)3534 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, int flags,
3535 RtldLockState *lockstate)
3536 {
3537 Obj_Entry *obj;
3538 int error;
3539
3540 for (error = 0, obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
3541 if (obj->marker)
3542 continue;
3543 error = relocate_object(obj, bind_now, rtldobj, flags,
3544 lockstate);
3545 if (error == -1)
3546 break;
3547 }
3548 return (error);
3549 }
3550
3551 /*
3552 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
3553 * referencing STT_GNU_IFUNC symbols is postponed till the other
3554 * relocations are done. The indirect functions specified as
3555 * ifunc are allowed to call other symbols, so we need to have
3556 * objects relocated before asking for resolution from indirects.
3557 *
3558 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
3559 * instead of the usual lazy handling of PLT slots. It is
3560 * consistent with how GNU does it.
3561 */
3562 static int
resolve_object_ifunc(Obj_Entry * obj,bool bind_now,int flags,RtldLockState * lockstate)3563 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
3564 RtldLockState *lockstate)
3565 {
3566 if (obj->ifuncs_resolved)
3567 return (0);
3568 obj->ifuncs_resolved = true;
3569 if (!obj->irelative && !obj->irelative_nonplt &&
3570 !((obj->bind_now || bind_now) && obj->gnu_ifunc) &&
3571 !obj->non_plt_gnu_ifunc)
3572 return (0);
3573 if (obj_disable_relro(obj) == -1 ||
3574 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) ||
3575 (obj->irelative_nonplt &&
3576 reloc_iresolve_nonplt(obj, lockstate) == -1) ||
3577 ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
3578 reloc_gnu_ifunc(obj, flags, lockstate) == -1) ||
3579 (obj->non_plt_gnu_ifunc &&
3580 reloc_non_plt(obj, &obj_rtld, flags | SYMLOOK_IFUNC,
3581 lockstate) == -1) ||
3582 obj_enforce_relro(obj) == -1)
3583 return (-1);
3584 return (0);
3585 }
3586
3587 static int
initlist_objects_ifunc(Objlist * list,bool bind_now,int flags,RtldLockState * lockstate)3588 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
3589 RtldLockState *lockstate)
3590 {
3591 Objlist_Entry *elm;
3592 Obj_Entry *obj;
3593
3594 STAILQ_FOREACH(elm, list, link) {
3595 obj = elm->obj;
3596 if (obj->marker)
3597 continue;
3598 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1)
3599 return (-1);
3600 }
3601 return (0);
3602 }
3603
3604 /*
3605 * Cleanup procedure. It will be called (by the atexit mechanism) just
3606 * before the process exits.
3607 */
3608 static void
rtld_exit(void)3609 rtld_exit(void)
3610 {
3611 RtldLockState lockstate;
3612
3613 wlock_acquire(rtld_bind_lock, &lockstate);
3614 dbg("rtld_exit()");
3615 objlist_call_fini(&list_fini, NULL, &lockstate);
3616 /* No need to remove the items from the list, since we are exiting. */
3617 if (!libmap_disable)
3618 lm_fini();
3619 lock_release(rtld_bind_lock, &lockstate);
3620 }
3621
3622 static void
rtld_nop_exit(void)3623 rtld_nop_exit(void)
3624 {
3625 }
3626
3627 /*
3628 * Parse string of the format '#number/name", where number must be a
3629 * decimal number of the opened file descriptor listed in
3630 * LD_LIBRARY_PATH_FDS. If successful, tries to open dso name under
3631 * dirfd number and returns resulting fd.
3632 * On any error, returns -1.
3633 */
3634 static int
try_fds_open(const char * name,const char * path)3635 try_fds_open(const char *name, const char *path)
3636 {
3637 const char *n;
3638 char *envcopy, *fdstr, *last_token, *ncopy;
3639 size_t len;
3640 int fd, dirfd, dirfd_path;
3641
3642 if (!trust || name[0] != '#' || path == NULL)
3643 return (-1);
3644
3645 name++;
3646 n = strchr(name, '/');
3647 if (n == NULL)
3648 return (-1);
3649 len = n - name;
3650 ncopy = xmalloc(len + 1);
3651 memcpy(ncopy, name, len);
3652 ncopy[len] = '\0';
3653 dirfd = parse_integer(ncopy);
3654 free(ncopy);
3655 if (dirfd == -1)
3656 return (-1);
3657
3658 envcopy = xstrdup(path);
3659 dirfd_path = -1;
3660 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL;
3661 fdstr = strtok_r(NULL, ":", &last_token)) {
3662 dirfd_path = parse_integer(fdstr);
3663 if (dirfd_path == dirfd)
3664 break;
3665 }
3666 free(envcopy);
3667 if (dirfd_path != dirfd)
3668 return (-1);
3669
3670 fd = __sys_openat(dirfd, n + 1, O_RDONLY | O_CLOEXEC | O_VERIFY);
3671 return (fd);
3672 }
3673
3674 /*
3675 * Iterate over a search path, translate each element, and invoke the
3676 * callback on the result.
3677 */
3678 static void *
path_enumerate(const char * path,path_enum_proc callback,const char * refobj_path,void * arg)3679 path_enumerate(const char *path, path_enum_proc callback,
3680 const char *refobj_path, void *arg)
3681 {
3682 const char *trans;
3683 if (path == NULL)
3684 return (NULL);
3685
3686 path += strspn(path, ":;");
3687 while (*path != '\0') {
3688 size_t len;
3689 char *res;
3690
3691 len = strcspn(path, ":;");
3692 trans = lm_findn(refobj_path, path, len);
3693 if (trans)
3694 res = callback(trans, strlen(trans), arg);
3695 else
3696 res = callback(path, len, arg);
3697
3698 if (res != NULL)
3699 return (res);
3700
3701 path += len;
3702 path += strspn(path, ":;");
3703 }
3704
3705 return (NULL);
3706 }
3707
3708 struct try_library_args {
3709 const char *name;
3710 size_t namelen;
3711 char *buffer;
3712 size_t buflen;
3713 int fd;
3714 };
3715
3716 static void *
try_library_path(const char * dir,size_t dirlen,void * param)3717 try_library_path(const char *dir, size_t dirlen, void *param)
3718 {
3719 struct try_library_args *arg;
3720 int fd;
3721
3722 arg = param;
3723 if (*dir == '/' || trust) {
3724 char *pathname;
3725
3726 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
3727 return (NULL);
3728
3729 pathname = arg->buffer;
3730 strncpy(pathname, dir, dirlen);
3731 pathname[dirlen] = '/';
3732 strcpy(pathname + dirlen + 1, arg->name);
3733
3734 dbg(" Trying \"%s\"", pathname);
3735 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY);
3736 if (fd >= 0) {
3737 dbg(" Opened \"%s\", fd %d", pathname, fd);
3738 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
3739 strcpy(pathname, arg->buffer);
3740 arg->fd = fd;
3741 return (pathname);
3742 } else {
3743 dbg(" Failed to open \"%s\": %s", pathname,
3744 rtld_strerror(errno));
3745 }
3746 }
3747 return (NULL);
3748 }
3749
3750 static char *
search_library_path(const char * name,const char * path,const char * refobj_path,int * fdp)3751 search_library_path(const char *name, const char *path, const char *refobj_path,
3752 int *fdp)
3753 {
3754 char *p;
3755 struct try_library_args arg;
3756
3757 if (path == NULL)
3758 return (NULL);
3759
3760 arg.name = name;
3761 arg.namelen = strlen(name);
3762 arg.buffer = xmalloc(PATH_MAX);
3763 arg.buflen = PATH_MAX;
3764 arg.fd = -1;
3765
3766 p = path_enumerate(path, try_library_path, refobj_path, &arg);
3767 *fdp = arg.fd;
3768
3769 free(arg.buffer);
3770
3771 return (p);
3772 }
3773
3774 /*
3775 * Finds the library with the given name using the directory descriptors
3776 * listed in the LD_LIBRARY_PATH_FDS environment variable.
3777 *
3778 * Returns a freshly-opened close-on-exec file descriptor for the library,
3779 * or -1 if the library cannot be found.
3780 */
3781 static char *
search_library_pathfds(const char * name,const char * path,int * fdp)3782 search_library_pathfds(const char *name, const char *path, int *fdp)
3783 {
3784 char *envcopy, *fdstr, *found, *last_token;
3785 size_t len;
3786 int dirfd, fd;
3787
3788 dbg("%s('%s', '%s', fdp)", __func__, name, path);
3789
3790 /* Don't load from user-specified libdirs into setuid binaries. */
3791 if (!trust)
3792 return (NULL);
3793
3794 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */
3795 if (path == NULL)
3796 return (NULL);
3797
3798 /* LD_LIBRARY_PATH_FDS only works with relative paths. */
3799 if (name[0] == '/') {
3800 dbg("Absolute path (%s) passed to %s", name, __func__);
3801 return (NULL);
3802 }
3803
3804 /*
3805 * Use strtok_r() to walk the FD:FD:FD list. This requires a local
3806 * copy of the path, as strtok_r rewrites separator tokens
3807 * with '\0'.
3808 */
3809 found = NULL;
3810 envcopy = xstrdup(path);
3811 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL;
3812 fdstr = strtok_r(NULL, ":", &last_token)) {
3813 dirfd = parse_integer(fdstr);
3814 if (dirfd < 0) {
3815 _rtld_error("failed to parse directory FD: '%s'",
3816 fdstr);
3817 break;
3818 }
3819 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY);
3820 if (fd >= 0) {
3821 *fdp = fd;
3822 len = strlen(fdstr) + strlen(name) + 3;
3823 found = xmalloc(len);
3824 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) <
3825 0) {
3826 _rtld_error("error generating '%d/%s'", dirfd,
3827 name);
3828 rtld_die();
3829 }
3830 dbg("open('%s') => %d", found, fd);
3831 break;
3832 }
3833 }
3834 free(envcopy);
3835
3836 return (found);
3837 }
3838
3839 int
dlclose(void * handle)3840 dlclose(void *handle)
3841 {
3842 RtldLockState lockstate;
3843 int error;
3844
3845 wlock_acquire(rtld_bind_lock, &lockstate);
3846 error = dlclose_locked(handle, &lockstate);
3847 lock_release(rtld_bind_lock, &lockstate);
3848 return (error);
3849 }
3850
3851 static int
dlclose_locked(void * handle,RtldLockState * lockstate)3852 dlclose_locked(void *handle, RtldLockState *lockstate)
3853 {
3854 Obj_Entry *root;
3855
3856 root = dlcheck(handle);
3857 if (root == NULL)
3858 return (-1);
3859 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
3860 root->path);
3861
3862 /* Unreference the object and its dependencies. */
3863 root->dl_refcount--;
3864
3865 if (root->refcount == 1) {
3866 /*
3867 * The object will be no longer referenced, so we must unload
3868 * it. First, call the fini functions.
3869 */
3870 objlist_call_fini(&list_fini, root, lockstate);
3871
3872 unref_dag(root);
3873
3874 /* Finish cleaning up the newly-unreferenced objects. */
3875 GDB_STATE(RT_DELETE, &root->linkmap);
3876 unload_object(root, lockstate);
3877 GDB_STATE(RT_CONSISTENT, NULL);
3878 } else
3879 unref_dag(root);
3880
3881 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
3882 return (0);
3883 }
3884
3885 char *
dlerror(void)3886 dlerror(void)
3887 {
3888 if (*(lockinfo.dlerror_seen()) != 0)
3889 return (NULL);
3890 *lockinfo.dlerror_seen() = 1;
3891 return (lockinfo.dlerror_loc());
3892 }
3893
3894 /*
3895 * This function is deprecated and has no effect.
3896 */
3897 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))3898 dllockinit(void *context, void *(*_lock_create)(void *context)__unused,
3899 void (*_rlock_acquire)(void *lock) __unused,
3900 void (*_wlock_acquire)(void *lock) __unused,
3901 void (*_lock_release)(void *lock) __unused,
3902 void (*_lock_destroy)(void *lock) __unused,
3903 void (*context_destroy)(void *context))
3904 {
3905 static void *cur_context;
3906 static void (*cur_context_destroy)(void *);
3907
3908 /* Just destroy the context from the previous call, if necessary. */
3909 if (cur_context_destroy != NULL)
3910 cur_context_destroy(cur_context);
3911 cur_context = context;
3912 cur_context_destroy = context_destroy;
3913 }
3914
3915 void *
dlopen(const char * name,int mode)3916 dlopen(const char *name, int mode)
3917 {
3918 return (rtld_dlopen(name, -1, mode));
3919 }
3920
3921 void *
fdlopen(int fd,int mode)3922 fdlopen(int fd, int mode)
3923 {
3924 return (rtld_dlopen(NULL, fd, mode));
3925 }
3926
3927 static void *
rtld_dlopen(const char * name,int fd,int mode)3928 rtld_dlopen(const char *name, int fd, int mode)
3929 {
3930 RtldLockState lockstate;
3931 int lo_flags;
3932
3933 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
3934 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
3935 if (ld_tracing != NULL) {
3936 rlock_acquire(rtld_bind_lock, &lockstate);
3937 if (sigsetjmp(lockstate.env, 0) != 0)
3938 lock_upgrade(rtld_bind_lock, &lockstate);
3939 environ = __DECONST(char **,
3940 *get_program_var_addr("environ", &lockstate));
3941 lock_release(rtld_bind_lock, &lockstate);
3942 }
3943 lo_flags = RTLD_LO_DLOPEN;
3944 if (mode & RTLD_NODELETE)
3945 lo_flags |= RTLD_LO_NODELETE;
3946 if (mode & RTLD_NOLOAD)
3947 lo_flags |= RTLD_LO_NOLOAD;
3948 if (mode & RTLD_DEEPBIND)
3949 lo_flags |= RTLD_LO_DEEPBIND;
3950 if (ld_tracing != NULL)
3951 lo_flags |= RTLD_LO_TRACE | RTLD_LO_IGNSTLS;
3952
3953 return (dlopen_object(name, fd, obj_main, lo_flags,
3954 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
3955 }
3956
3957 static void
dlopen_cleanup(Obj_Entry * obj,RtldLockState * lockstate)3958 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate)
3959 {
3960 obj->dl_refcount--;
3961 unref_dag(obj);
3962 if (obj->refcount == 0)
3963 unload_object(obj, lockstate);
3964 }
3965
3966 static Obj_Entry *
dlopen_object(const char * name,int fd,Obj_Entry * refobj,int lo_flags,int mode,RtldLockState * lockstate)3967 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
3968 int mode, RtldLockState *lockstate)
3969 {
3970 Obj_Entry *obj;
3971 Objlist initlist;
3972 RtldLockState mlockstate;
3973 int result;
3974
3975 dbg(
3976 "dlopen_object name \"%s\" fd %d refobj \"%s\" lo_flags %#x mode %#x",
3977 name != NULL ? name : "<null>", fd,
3978 refobj == NULL ? "<null>" : refobj->path, lo_flags, mode);
3979 objlist_init(&initlist);
3980
3981 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
3982 wlock_acquire(rtld_bind_lock, &mlockstate);
3983 lockstate = &mlockstate;
3984 }
3985 GDB_STATE(RT_ADD, NULL);
3986
3987 obj = NULL;
3988 if (name == NULL && fd == -1) {
3989 obj = obj_main;
3990 obj->refcount++;
3991 } else {
3992 obj = load_object(name, fd, refobj, lo_flags);
3993 }
3994
3995 if (obj != NULL) {
3996 obj->dl_refcount++;
3997 if ((mode & RTLD_GLOBAL) != 0 &&
3998 objlist_find(&list_global, obj) == NULL)
3999 objlist_push_tail(&list_global, obj);
4000
4001 if (!obj->init_done) {
4002 /* We loaded something new and have to init something.
4003 */
4004 if ((lo_flags & RTLD_LO_DEEPBIND) != 0)
4005 obj->deepbind = true;
4006 result = 0;
4007 if ((lo_flags & (RTLD_LO_EARLY |
4008 RTLD_LO_IGNSTLS)) == 0 &&
4009 obj->static_tls && !allocate_tls_offset(obj)) {
4010 _rtld_error(
4011 "%s: No space available for static Thread Local Storage",
4012 obj->path);
4013 result = -1;
4014 }
4015 if (result != -1)
4016 result = load_needed_objects(obj,
4017 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY |
4018 RTLD_LO_IGNSTLS | RTLD_LO_TRACE));
4019 init_dag(obj);
4020 ref_dag(obj);
4021 if (result != -1)
4022 result = rtld_verify_versions(&obj->dagmembers);
4023 if (result != -1 && ld_tracing)
4024 goto trace;
4025 if (result == -1 || relocate_object_dag(obj,
4026 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
4027 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
4028 lockstate) == -1) {
4029 dlopen_cleanup(obj, lockstate);
4030 obj = NULL;
4031 } else if ((lo_flags & RTLD_LO_EARLY) != 0) {
4032 /*
4033 * Do not call the init functions for early
4034 * loaded filtees. The image is still not
4035 * initialized enough for them to work.
4036 *
4037 * Our object is found by the global object list
4038 * and will be ordered among all init calls done
4039 * right before transferring control to main.
4040 */
4041 } else {
4042 /* Make list of init functions to call. */
4043 initlist_for_loaded_obj(obj, obj, &initlist);
4044 }
4045 /*
4046 * Process all no_delete or global objects here, given
4047 * them own DAGs to prevent their dependencies from
4048 * being unloaded. This has to be done after we have
4049 * loaded all of the dependencies, so that we do not
4050 * miss any.
4051 */
4052 if (obj != NULL)
4053 process_z(obj);
4054 } else {
4055 /*
4056 * Bump the reference counts for objects on this DAG. If
4057 * this is the first dlopen() call for the object that
4058 * was already loaded as a dependency, initialize the
4059 * dag starting at it.
4060 */
4061 init_dag(obj);
4062 ref_dag(obj);
4063
4064 if ((lo_flags & RTLD_LO_TRACE) != 0)
4065 goto trace;
4066 }
4067 if (obj != NULL &&
4068 ((lo_flags & RTLD_LO_NODELETE) != 0 || obj->z_nodelete) &&
4069 !obj->ref_nodel) {
4070 dbg("obj %s nodelete", obj->path);
4071 ref_dag(obj);
4072 obj->z_nodelete = obj->ref_nodel = true;
4073 }
4074 }
4075
4076 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
4077 name);
4078 GDB_STATE(RT_CONSISTENT, obj ? &obj->linkmap : NULL);
4079
4080 if ((lo_flags & RTLD_LO_EARLY) == 0) {
4081 map_stacks_exec(lockstate);
4082 if (obj != NULL)
4083 distribute_static_tls(&initlist);
4084 }
4085
4086 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) ==
4087 RTLD_NOW, (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
4088 lockstate) == -1) {
4089 objlist_clear(&initlist);
4090 dlopen_cleanup(obj, lockstate);
4091 if (lockstate == &mlockstate)
4092 lock_release(rtld_bind_lock, lockstate);
4093 return (NULL);
4094 }
4095
4096 if ((lo_flags & RTLD_LO_EARLY) == 0) {
4097 /* Call the init functions. */
4098 objlist_call_init(&initlist, lockstate);
4099 }
4100 objlist_clear(&initlist);
4101 if (lockstate == &mlockstate)
4102 lock_release(rtld_bind_lock, lockstate);
4103 return (obj);
4104 trace:
4105 trace_loaded_objects(obj, false);
4106 if (lockstate == &mlockstate)
4107 lock_release(rtld_bind_lock, lockstate);
4108 exit(0);
4109 }
4110
4111 static void *
do_dlsym(void * handle,const char * name,void * retaddr,const Ver_Entry * ve,int flags)4112 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
4113 int flags)
4114 {
4115 DoneList donelist;
4116 const Obj_Entry *obj, *defobj;
4117 const Elf_Sym *def;
4118 SymLook req;
4119 RtldLockState lockstate;
4120 tls_index ti;
4121 void *sym;
4122 int res;
4123
4124 def = NULL;
4125 defobj = NULL;
4126 symlook_init(&req, name);
4127 req.ventry = ve;
4128 req.flags = flags | SYMLOOK_IN_PLT;
4129 req.lockstate = &lockstate;
4130
4131 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name);
4132 rlock_acquire(rtld_bind_lock, &lockstate);
4133 if (sigsetjmp(lockstate.env, 0) != 0) {
4134 lock_upgrade(rtld_bind_lock, &lockstate);
4135 free(req.donelist_mem);
4136 req.donelist_mem = NULL;
4137 }
4138 if (handle == NULL || handle == RTLD_NEXT || handle == RTLD_DEFAULT ||
4139 handle == RTLD_SELF) {
4140 if ((obj = obj_from_addr(retaddr)) == NULL) {
4141 _rtld_error("Cannot determine caller's shared object");
4142 lock_release(rtld_bind_lock, &lockstate);
4143 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
4144 return (NULL);
4145 }
4146 if (handle == NULL) { /* Just the caller's shared object. */
4147 res = symlook_obj(&req, obj);
4148 if (res == 0) {
4149 def = req.sym_out;
4150 defobj = req.defobj_out;
4151 }
4152 } else if (handle == RTLD_NEXT || /* Objects after caller's */
4153 handle == RTLD_SELF) { /* ... caller included */
4154 if (handle == RTLD_NEXT)
4155 obj = globallist_next(obj);
4156 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
4157 if (obj->marker)
4158 continue;
4159 res = symlook_obj(&req, obj);
4160 if (res == 0) {
4161 if (def == NULL ||
4162 (ld_dynamic_weak &&
4163 ELF_ST_BIND(
4164 req.sym_out->st_info) !=
4165 STB_WEAK)) {
4166 def = req.sym_out;
4167 defobj = req.defobj_out;
4168 if (!ld_dynamic_weak ||
4169 ELF_ST_BIND(def->st_info) !=
4170 STB_WEAK)
4171 break;
4172 }
4173 }
4174 }
4175 /*
4176 * Search the dynamic linker itself, and possibly
4177 * resolve the symbol from there. This is how the
4178 * application links to dynamic linker services such as
4179 * dlopen. Note that we ignore ld_dynamic_weak == false
4180 * case, always overriding weak symbols by rtld
4181 * definitions.
4182 */
4183 if (def == NULL ||
4184 ELF_ST_BIND(def->st_info) == STB_WEAK) {
4185 res = symlook_obj(&req, &obj_rtld);
4186 if (res == 0) {
4187 def = req.sym_out;
4188 defobj = req.defobj_out;
4189 }
4190 }
4191 } else {
4192 assert(handle == RTLD_DEFAULT);
4193 res = symlook_default(&req, obj);
4194 if (res == 0) {
4195 defobj = req.defobj_out;
4196 def = req.sym_out;
4197 }
4198 }
4199 } else {
4200 if ((obj = dlcheck(handle)) == NULL) {
4201 lock_release(rtld_bind_lock, &lockstate);
4202 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
4203 return (NULL);
4204 }
4205
4206 donelist_init(&donelist, &req);
4207 if (obj->mainprog) {
4208 /* Handle obtained by dlopen(NULL, ...) implies global
4209 * scope. */
4210 res = symlook_global(&req, &donelist);
4211 if (res == 0) {
4212 def = req.sym_out;
4213 defobj = req.defobj_out;
4214 }
4215 /*
4216 * Search the dynamic linker itself, and possibly
4217 * resolve the symbol from there. This is how the
4218 * application links to dynamic linker services such as
4219 * dlopen.
4220 */
4221 if (def == NULL ||
4222 ELF_ST_BIND(def->st_info) == STB_WEAK) {
4223 res = symlook_obj(&req, &obj_rtld);
4224 if (res == 0) {
4225 def = req.sym_out;
4226 defobj = req.defobj_out;
4227 }
4228 }
4229 } else {
4230 /* Search the whole DAG rooted at the given object. */
4231 res = symlook_list(&req, &obj->dagmembers, &donelist);
4232 if (res == 0) {
4233 def = req.sym_out;
4234 defobj = req.defobj_out;
4235 }
4236 }
4237 donelist_free(&donelist);
4238 }
4239
4240 if (def != NULL) {
4241 lock_release(rtld_bind_lock, &lockstate);
4242
4243 /*
4244 * The value required by the caller is derived from the value
4245 * of the symbol. this is simply the relocated value of the
4246 * symbol.
4247 */
4248 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
4249 sym = make_function_pointer(def, defobj);
4250 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
4251 sym = rtld_resolve_ifunc(defobj, def);
4252 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
4253 ti.ti_module = defobj->tlsindex;
4254 ti.ti_offset = def->st_value - TLS_DTV_OFFSET;
4255 sym = __tls_get_addr(&ti);
4256 } else
4257 sym = defobj->relocbase + def->st_value;
4258 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name);
4259 return (sym);
4260 }
4261
4262 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "",
4263 ve != NULL ? ve->name : "");
4264 lock_release(rtld_bind_lock, &lockstate);
4265 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
4266 return (NULL);
4267 }
4268
4269 void *
dlsym(void * handle,const char * name)4270 dlsym(void *handle, const char *name)
4271 {
4272 return (do_dlsym(handle, name, __builtin_return_address(0), NULL,
4273 SYMLOOK_DLSYM));
4274 }
4275
4276 dlfunc_t
dlfunc(void * handle,const char * name)4277 dlfunc(void *handle, const char *name)
4278 {
4279 union {
4280 void *d;
4281 dlfunc_t f;
4282 } rv;
4283
4284 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
4285 SYMLOOK_DLSYM);
4286 return (rv.f);
4287 }
4288
4289 void *
dlvsym(void * handle,const char * name,const char * version)4290 dlvsym(void *handle, const char *name, const char *version)
4291 {
4292 Ver_Entry ventry;
4293
4294 ventry.name = version;
4295 ventry.file = NULL;
4296 ventry.hash = elf_hash(version);
4297 ventry.flags = 0;
4298 return (do_dlsym(handle, name, __builtin_return_address(0), &ventry,
4299 SYMLOOK_DLSYM));
4300 }
4301
4302 int
_rtld_addr_phdr(const void * addr,struct dl_phdr_info * phdr_info)4303 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
4304 {
4305 const Obj_Entry *obj;
4306 RtldLockState lockstate;
4307
4308 rlock_acquire(rtld_bind_lock, &lockstate);
4309 obj = obj_from_addr(addr);
4310 if (obj == NULL) {
4311 _rtld_error("No shared object contains address");
4312 lock_release(rtld_bind_lock, &lockstate);
4313 return (0);
4314 }
4315 rtld_fill_dl_phdr_info(obj, phdr_info);
4316 lock_release(rtld_bind_lock, &lockstate);
4317 return (1);
4318 }
4319
4320 int
dladdr(const void * addr,Dl_info * info)4321 dladdr(const void *addr, Dl_info *info)
4322 {
4323 const Obj_Entry *obj;
4324 const Elf_Sym *def;
4325 void *symbol_addr;
4326 unsigned long symoffset;
4327 RtldLockState lockstate;
4328
4329 rlock_acquire(rtld_bind_lock, &lockstate);
4330 obj = obj_from_addr(addr);
4331 if (obj == NULL) {
4332 _rtld_error("No shared object contains address");
4333 lock_release(rtld_bind_lock, &lockstate);
4334 return (0);
4335 }
4336 info->dli_fname = obj->path;
4337 info->dli_fbase = obj->mapbase;
4338 info->dli_saddr = (void *)0;
4339 info->dli_sname = NULL;
4340
4341 /*
4342 * Walk the symbol list looking for the symbol whose address is
4343 * closest to the address sent in.
4344 */
4345 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
4346 def = obj->symtab + symoffset;
4347
4348 /*
4349 * For skip the symbol if st_shndx is either SHN_UNDEF or
4350 * SHN_COMMON.
4351 */
4352 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
4353 continue;
4354
4355 /*
4356 * If the symbol is greater than the specified address, or if it
4357 * is further away from addr than the current nearest symbol,
4358 * then reject it.
4359 */
4360 symbol_addr = obj->relocbase + def->st_value;
4361 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
4362 continue;
4363
4364 /* Update our idea of the nearest symbol. */
4365 info->dli_sname = obj->strtab + def->st_name;
4366 info->dli_saddr = symbol_addr;
4367
4368 /* Exact match? */
4369 if (info->dli_saddr == addr)
4370 break;
4371 }
4372 lock_release(rtld_bind_lock, &lockstate);
4373 return (1);
4374 }
4375
4376 int
dlinfo(void * handle,int request,void * p)4377 dlinfo(void *handle, int request, void *p)
4378 {
4379 const Obj_Entry *obj;
4380 RtldLockState lockstate;
4381 int error;
4382
4383 rlock_acquire(rtld_bind_lock, &lockstate);
4384
4385 if (handle == NULL || handle == RTLD_SELF) {
4386 void *retaddr;
4387
4388 retaddr = __builtin_return_address(0); /* __GNUC__ only */
4389 if ((obj = obj_from_addr(retaddr)) == NULL)
4390 _rtld_error("Cannot determine caller's shared object");
4391 } else
4392 obj = dlcheck(handle);
4393
4394 if (obj == NULL) {
4395 lock_release(rtld_bind_lock, &lockstate);
4396 return (-1);
4397 }
4398
4399 error = 0;
4400 switch (request) {
4401 case RTLD_DI_LINKMAP:
4402 *((struct link_map const **)p) = &obj->linkmap;
4403 break;
4404 case RTLD_DI_ORIGIN:
4405 error = rtld_dirname(obj->path, p);
4406 break;
4407
4408 case RTLD_DI_SERINFOSIZE:
4409 case RTLD_DI_SERINFO:
4410 error = do_search_info(obj, request, (struct dl_serinfo *)p);
4411 break;
4412
4413 default:
4414 _rtld_error("Invalid request %d passed to dlinfo()", request);
4415 error = -1;
4416 }
4417
4418 lock_release(rtld_bind_lock, &lockstate);
4419
4420 return (error);
4421 }
4422
4423 static void
rtld_fill_dl_phdr_info(const Obj_Entry * obj,struct dl_phdr_info * phdr_info)4424 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
4425 {
4426 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
4427 phdr_info->dlpi_name = obj->path;
4428 phdr_info->dlpi_phdr = obj->phdr;
4429 phdr_info->dlpi_phnum = obj->phnum;
4430 phdr_info->dlpi_tls_modid = obj->tlsindex;
4431 phdr_info->dlpi_tls_data = (char *)tls_get_addr_slow(_tcb_get(),
4432 obj->tlsindex, 0, true);
4433 phdr_info->dlpi_adds = obj_loads;
4434 phdr_info->dlpi_subs = obj_loads - obj_count;
4435 }
4436
4437 /*
4438 * It's completely UB to actually use this, so extreme caution is advised. It's
4439 * probably not what you want.
4440 */
4441 int
_dl_iterate_phdr_locked(__dl_iterate_hdr_callback callback,void * param)4442 _dl_iterate_phdr_locked(__dl_iterate_hdr_callback callback, void *param)
4443 {
4444 struct dl_phdr_info phdr_info;
4445 Obj_Entry *obj;
4446 int error;
4447
4448 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;
4449 obj = globallist_next(obj)) {
4450 rtld_fill_dl_phdr_info(obj, &phdr_info);
4451 error = callback(&phdr_info, sizeof(phdr_info), param);
4452 if (error != 0)
4453 return (error);
4454 }
4455
4456 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info);
4457 return (callback(&phdr_info, sizeof(phdr_info), param));
4458 }
4459
4460 int
dl_iterate_phdr(__dl_iterate_hdr_callback callback,void * param)4461 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
4462 {
4463 struct dl_phdr_info phdr_info;
4464 Obj_Entry *obj, marker;
4465 RtldLockState bind_lockstate, phdr_lockstate;
4466 int error;
4467
4468 init_marker(&marker);
4469 error = 0;
4470
4471 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
4472 wlock_acquire(rtld_bind_lock, &bind_lockstate);
4473 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) {
4474 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next);
4475 rtld_fill_dl_phdr_info(obj, &phdr_info);
4476 hold_object(obj);
4477 lock_release(rtld_bind_lock, &bind_lockstate);
4478
4479 error = callback(&phdr_info, sizeof phdr_info, param);
4480
4481 wlock_acquire(rtld_bind_lock, &bind_lockstate);
4482 unhold_object(obj);
4483 obj = globallist_next(&marker);
4484 TAILQ_REMOVE(&obj_list, &marker, next);
4485 if (error != 0) {
4486 lock_release(rtld_bind_lock, &bind_lockstate);
4487 lock_release(rtld_phdr_lock, &phdr_lockstate);
4488 return (error);
4489 }
4490 }
4491
4492 if (error == 0) {
4493 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info);
4494 lock_release(rtld_bind_lock, &bind_lockstate);
4495 error = callback(&phdr_info, sizeof(phdr_info), param);
4496 }
4497 lock_release(rtld_phdr_lock, &phdr_lockstate);
4498 return (error);
4499 }
4500
4501 static void *
fill_search_info(const char * dir,size_t dirlen,void * param)4502 fill_search_info(const char *dir, size_t dirlen, void *param)
4503 {
4504 struct fill_search_info_args *arg;
4505
4506 arg = param;
4507
4508 if (arg->request == RTLD_DI_SERINFOSIZE) {
4509 arg->serinfo->dls_cnt++;
4510 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen +
4511 1;
4512 } else {
4513 struct dl_serpath *s_entry;
4514
4515 s_entry = arg->serpath;
4516 s_entry->dls_name = arg->strspace;
4517 s_entry->dls_flags = arg->flags;
4518
4519 strncpy(arg->strspace, dir, dirlen);
4520 arg->strspace[dirlen] = '\0';
4521
4522 arg->strspace += dirlen + 1;
4523 arg->serpath++;
4524 }
4525
4526 return (NULL);
4527 }
4528
4529 static int
do_search_info(const Obj_Entry * obj,int request,struct dl_serinfo * info)4530 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
4531 {
4532 struct dl_serinfo _info;
4533 struct fill_search_info_args args;
4534
4535 args.request = RTLD_DI_SERINFOSIZE;
4536 args.serinfo = &_info;
4537
4538 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
4539 _info.dls_cnt = 0;
4540
4541 path_enumerate(obj->rpath, fill_search_info, NULL, &args);
4542 path_enumerate(ld_library_path, fill_search_info, NULL, &args);
4543 path_enumerate(obj->runpath, fill_search_info, NULL, &args);
4544 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL,
4545 &args);
4546 if (!obj->z_nodeflib)
4547 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
4548 &args);
4549
4550 if (request == RTLD_DI_SERINFOSIZE) {
4551 info->dls_size = _info.dls_size;
4552 info->dls_cnt = _info.dls_cnt;
4553 return (0);
4554 }
4555
4556 if (info->dls_cnt != _info.dls_cnt ||
4557 info->dls_size != _info.dls_size) {
4558 _rtld_error(
4559 "Uninitialized Dl_serinfo struct passed to dlinfo()");
4560 return (-1);
4561 }
4562
4563 args.request = RTLD_DI_SERINFO;
4564 args.serinfo = info;
4565 args.serpath = &info->dls_serpath[0];
4566 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
4567
4568 args.flags = LA_SER_RUNPATH;
4569 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL)
4570 return (-1);
4571
4572 args.flags = LA_SER_LIBPATH;
4573 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) !=
4574 NULL)
4575 return (-1);
4576
4577 args.flags = LA_SER_RUNPATH;
4578 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL)
4579 return (-1);
4580
4581 args.flags = LA_SER_CONFIG;
4582 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL,
4583 &args) != NULL)
4584 return (-1);
4585
4586 args.flags = LA_SER_DEFAULT;
4587 if (!obj->z_nodeflib &&
4588 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
4589 &args) != NULL)
4590 return (-1);
4591 return (0);
4592 }
4593
4594 static int
rtld_dirname(const char * path,char * bname)4595 rtld_dirname(const char *path, char *bname)
4596 {
4597 const char *endp;
4598
4599 /* Empty or NULL string gets treated as "." */
4600 if (path == NULL || *path == '\0') {
4601 bname[0] = '.';
4602 bname[1] = '\0';
4603 return (0);
4604 }
4605
4606 /* Strip trailing slashes */
4607 endp = path + strlen(path) - 1;
4608 while (endp > path && *endp == '/')
4609 endp--;
4610
4611 /* Find the start of the dir */
4612 while (endp > path && *endp != '/')
4613 endp--;
4614
4615 /* Either the dir is "/" or there are no slashes */
4616 if (endp == path) {
4617 bname[0] = *endp == '/' ? '/' : '.';
4618 bname[1] = '\0';
4619 return (0);
4620 } else {
4621 do {
4622 endp--;
4623 } while (endp > path && *endp == '/');
4624 }
4625
4626 if (endp - path + 2 > PATH_MAX) {
4627 _rtld_error("Filename is too long: %s", path);
4628 return (-1);
4629 }
4630
4631 strncpy(bname, path, endp - path + 1);
4632 bname[endp - path + 1] = '\0';
4633 return (0);
4634 }
4635
4636 static int
rtld_dirname_abs(const char * path,char * base)4637 rtld_dirname_abs(const char *path, char *base)
4638 {
4639 char *last;
4640
4641 if (realpath(path, base) == NULL) {
4642 _rtld_error("realpath \"%s\" failed (%s)", path,
4643 rtld_strerror(errno));
4644 return (-1);
4645 }
4646 dbg("%s -> %s", path, base);
4647 last = strrchr(base, '/');
4648 if (last == NULL) {
4649 _rtld_error("non-abs result from realpath \"%s\"", path);
4650 return (-1);
4651 }
4652 if (last != base)
4653 *last = '\0';
4654 return (0);
4655 }
4656
4657 static void
linkmap_add(Obj_Entry * obj)4658 linkmap_add(Obj_Entry *obj)
4659 {
4660 struct link_map *l, *prev;
4661
4662 l = &obj->linkmap;
4663 l->l_name = obj->path;
4664 l->l_base = obj->mapbase;
4665 l->l_ld = obj->dynamic;
4666 l->l_addr = obj->relocbase;
4667
4668 if (r_debug.r_map == NULL) {
4669 r_debug.r_map = l;
4670 return;
4671 }
4672
4673 /*
4674 * Scan to the end of the list, but not past the entry for the
4675 * dynamic linker, which we want to keep at the very end.
4676 */
4677 for (prev = r_debug.r_map;
4678 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
4679 prev = prev->l_next)
4680 ;
4681
4682 /* Link in the new entry. */
4683 l->l_prev = prev;
4684 l->l_next = prev->l_next;
4685 if (l->l_next != NULL)
4686 l->l_next->l_prev = l;
4687 prev->l_next = l;
4688 }
4689
4690 static void
linkmap_delete(Obj_Entry * obj)4691 linkmap_delete(Obj_Entry *obj)
4692 {
4693 struct link_map *l;
4694
4695 l = &obj->linkmap;
4696 if (l->l_prev == NULL) {
4697 if ((r_debug.r_map = l->l_next) != NULL)
4698 l->l_next->l_prev = NULL;
4699 return;
4700 }
4701
4702 if ((l->l_prev->l_next = l->l_next) != NULL)
4703 l->l_next->l_prev = l->l_prev;
4704 }
4705
4706 /*
4707 * Function for the debugger to set a breakpoint on to gain control.
4708 *
4709 * The two parameters allow the debugger to easily find and determine
4710 * what the runtime loader is doing and to whom it is doing it.
4711 *
4712 * When the loadhook trap is hit (r_debug_state, set at program
4713 * initialization), the arguments can be found on the stack:
4714 *
4715 * +8 struct link_map *m
4716 * +4 struct r_debug *rd
4717 * +0 RetAddr
4718 */
4719 void
r_debug_state(struct r_debug * rd __unused,struct link_map * m __unused)4720 r_debug_state(struct r_debug *rd __unused, struct link_map *m __unused)
4721 {
4722 /*
4723 * The following is a hack to force the compiler to emit calls to
4724 * this function, even when optimizing. If the function is empty,
4725 * the compiler is not obliged to emit any code for calls to it,
4726 * even when marked __noinline. However, gdb depends on those
4727 * calls being made.
4728 */
4729 __compiler_membar();
4730 }
4731
4732 /*
4733 * A function called after init routines have completed. This can be used to
4734 * break before a program's entry routine is called, and can be used when
4735 * main is not available in the symbol table.
4736 */
4737 void
_r_debug_postinit(struct link_map * m __unused)4738 _r_debug_postinit(struct link_map *m __unused)
4739 {
4740 /* See r_debug_state(). */
4741 __compiler_membar();
4742 }
4743
4744 static void
release_object(Obj_Entry * obj)4745 release_object(Obj_Entry *obj)
4746 {
4747 if (obj->holdcount > 0) {
4748 obj->unholdfree = true;
4749 return;
4750 }
4751 munmap(obj->mapbase, obj->mapsize);
4752 linkmap_delete(obj);
4753 obj_free(obj);
4754 }
4755
4756 /*
4757 * Get address of the pointer variable in the main program.
4758 * Prefer non-weak symbol over the weak one.
4759 */
4760 static const void **
get_program_var_addr(const char * name,RtldLockState * lockstate)4761 get_program_var_addr(const char *name, RtldLockState *lockstate)
4762 {
4763 SymLook req;
4764 DoneList donelist;
4765 const void **res;
4766
4767 symlook_init(&req, name);
4768 req.lockstate = lockstate;
4769 donelist_init(&donelist, NULL);
4770 if (symlook_global(&req, &donelist) != 0)
4771 return (NULL);
4772 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
4773 res = (const void **)make_function_pointer(req.sym_out,
4774 req.defobj_out);
4775 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
4776 res = (const void **)rtld_resolve_ifunc(req.defobj_out,
4777 req.sym_out);
4778 else
4779 res = (const void **)(req.defobj_out->relocbase +
4780 req.sym_out->st_value);
4781 donelist_free(&donelist);
4782 return (res);
4783 }
4784
4785 /*
4786 * Set a pointer variable in the main program to the given value. This
4787 * is used to set key variables such as "environ" before any of the
4788 * init functions are called.
4789 */
4790 static void
set_program_var(const char * name,const void * value)4791 set_program_var(const char *name, const void *value)
4792 {
4793 const void **addr;
4794
4795 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
4796 dbg("\"%s\": *%p <-- %p", name, addr, value);
4797 *addr = value;
4798 }
4799 }
4800
4801 /*
4802 * Search the global objects, including dependencies and main object,
4803 * for the given symbol.
4804 */
4805 static int
symlook_global(SymLook * req,DoneList * donelist)4806 symlook_global(SymLook *req, DoneList *donelist)
4807 {
4808 SymLook req1;
4809 const Objlist_Entry *elm;
4810 int res;
4811
4812 symlook_init_from_req(&req1, req);
4813
4814 /* Search all objects loaded at program start up. */
4815 if (req->defobj_out == NULL || (ld_dynamic_weak &&
4816 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK)) {
4817 res = symlook_list(&req1, &list_main, donelist);
4818 if (res == 0 && (!ld_dynamic_weak || req->defobj_out == NULL ||
4819 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4820 req->sym_out = req1.sym_out;
4821 req->defobj_out = req1.defobj_out;
4822 assert(req->defobj_out != NULL);
4823 }
4824 }
4825
4826 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
4827 STAILQ_FOREACH(elm, &list_global, link) {
4828 if (req->defobj_out != NULL && (!ld_dynamic_weak ||
4829 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK))
4830 break;
4831 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
4832 if (res == 0 && (req->defobj_out == NULL ||
4833 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4834 req->sym_out = req1.sym_out;
4835 req->defobj_out = req1.defobj_out;
4836 assert(req->defobj_out != NULL);
4837 }
4838 }
4839
4840 return (req->sym_out != NULL ? 0 : ESRCH);
4841 }
4842
4843 /*
4844 * Given a symbol name in a referencing object, find the corresponding
4845 * definition of the symbol. Returns a pointer to the symbol, or NULL if
4846 * no definition was found. Returns a pointer to the Obj_Entry of the
4847 * defining object via the reference parameter DEFOBJ_OUT.
4848 */
4849 static int
symlook_default(SymLook * req,const Obj_Entry * refobj)4850 symlook_default(SymLook *req, const Obj_Entry *refobj)
4851 {
4852 DoneList donelist;
4853 const Objlist_Entry *elm;
4854 SymLook req1;
4855 int res;
4856
4857 donelist_init(&donelist, req);
4858 symlook_init_from_req(&req1, req);
4859
4860 /*
4861 * Look first in the referencing object if linked symbolically,
4862 * and similarly handle protected symbols.
4863 */
4864 res = symlook_obj(&req1, refobj);
4865 if (res == 0 && (refobj->symbolic ||
4866 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED ||
4867 refobj->deepbind)) {
4868 req->sym_out = req1.sym_out;
4869 req->defobj_out = req1.defobj_out;
4870 assert(req->defobj_out != NULL);
4871 }
4872 if (refobj->symbolic || req->defobj_out != NULL || refobj->deepbind)
4873 donelist_check(&donelist, refobj);
4874
4875 if (!refobj->deepbind)
4876 symlook_global(req, &donelist);
4877
4878 /* Search all dlopened DAGs containing the referencing object. */
4879 STAILQ_FOREACH(elm, &refobj->dldags, link) {
4880 if (req->sym_out != NULL && (!ld_dynamic_weak ||
4881 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK))
4882 break;
4883 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
4884 if (res == 0 && (req->sym_out == NULL ||
4885 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4886 req->sym_out = req1.sym_out;
4887 req->defobj_out = req1.defobj_out;
4888 assert(req->defobj_out != NULL);
4889 }
4890 }
4891
4892 if (refobj->deepbind)
4893 symlook_global(req, &donelist);
4894
4895 /*
4896 * Search the dynamic linker itself, and possibly resolve the
4897 * symbol from there. This is how the application links to
4898 * dynamic linker services such as dlopen.
4899 */
4900 if (req->sym_out == NULL ||
4901 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
4902 res = symlook_obj(&req1, &obj_rtld);
4903 if (res == 0) {
4904 req->sym_out = req1.sym_out;
4905 req->defobj_out = req1.defobj_out;
4906 assert(req->defobj_out != NULL);
4907 }
4908 }
4909
4910 donelist_free(&donelist);
4911 return (req->sym_out != NULL ? 0 : ESRCH);
4912 }
4913
4914 static int
symlook_list(SymLook * req,const Objlist * objlist,DoneList * dlp)4915 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
4916 {
4917 const Elf_Sym *def;
4918 const Obj_Entry *defobj;
4919 const Objlist_Entry *elm;
4920 SymLook req1;
4921 int res;
4922
4923 def = NULL;
4924 defobj = NULL;
4925 STAILQ_FOREACH(elm, objlist, link) {
4926 if (donelist_check(dlp, elm->obj))
4927 continue;
4928 symlook_init_from_req(&req1, req);
4929 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
4930 if (def == NULL || (ld_dynamic_weak &&
4931 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4932 def = req1.sym_out;
4933 defobj = req1.defobj_out;
4934 if (!ld_dynamic_weak ||
4935 ELF_ST_BIND(def->st_info) != STB_WEAK)
4936 break;
4937 }
4938 }
4939 }
4940 if (def != NULL) {
4941 req->sym_out = def;
4942 req->defobj_out = defobj;
4943 return (0);
4944 }
4945 return (ESRCH);
4946 }
4947
4948 /*
4949 * Search the chain of DAGS cointed to by the given Needed_Entry
4950 * for a symbol of the given name. Each DAG is scanned completely
4951 * before advancing to the next one. Returns a pointer to the symbol,
4952 * or NULL if no definition was found.
4953 */
4954 static int
symlook_needed(SymLook * req,const Needed_Entry * needed,DoneList * dlp)4955 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
4956 {
4957 const Elf_Sym *def;
4958 const Needed_Entry *n;
4959 const Obj_Entry *defobj;
4960 SymLook req1;
4961 int res;
4962
4963 def = NULL;
4964 defobj = NULL;
4965 symlook_init_from_req(&req1, req);
4966 for (n = needed; n != NULL; n = n->next) {
4967 if (n->obj == NULL || (res = symlook_list(&req1,
4968 &n->obj->dagmembers, dlp)) != 0)
4969 continue;
4970 if (def == NULL || (ld_dynamic_weak &&
4971 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4972 def = req1.sym_out;
4973 defobj = req1.defobj_out;
4974 if (!ld_dynamic_weak ||
4975 ELF_ST_BIND(def->st_info) != STB_WEAK)
4976 break;
4977 }
4978 }
4979 if (def != NULL) {
4980 req->sym_out = def;
4981 req->defobj_out = defobj;
4982 return (0);
4983 }
4984 return (ESRCH);
4985 }
4986
4987 static int
symlook_obj_load_filtees(SymLook * req,SymLook * req1,const Obj_Entry * obj,Needed_Entry * needed)4988 symlook_obj_load_filtees(SymLook *req, SymLook *req1, const Obj_Entry *obj,
4989 Needed_Entry *needed)
4990 {
4991 DoneList donelist;
4992 int flags, res;
4993
4994 flags = (req->flags & SYMLOOK_EARLY) != 0 ? RTLD_LO_EARLY : 0;
4995 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
4996 donelist_init(&donelist, NULL);
4997 symlook_init_from_req(req1, req);
4998 res = symlook_needed(req1, needed, &donelist);
4999 donelist_free(&donelist);
5000 return (res);
5001 }
5002
5003 /*
5004 * Search the symbol table of a single shared object for a symbol of
5005 * the given name and version, if requested. Returns a pointer to the
5006 * symbol, or NULL if no definition was found. If the object is
5007 * filter, return filtered symbol from filtee.
5008 *
5009 * The symbol's hash value is passed in for efficiency reasons; that
5010 * eliminates many recomputations of the hash value.
5011 */
5012 int
symlook_obj(SymLook * req,const Obj_Entry * obj)5013 symlook_obj(SymLook *req, const Obj_Entry *obj)
5014 {
5015 SymLook req1;
5016 int res, mres;
5017
5018 /*
5019 * If there is at least one valid hash at this point, we prefer to
5020 * use the faster GNU version if available.
5021 */
5022 if (obj->valid_hash_gnu)
5023 mres = symlook_obj1_gnu(req, obj);
5024 else if (obj->valid_hash_sysv)
5025 mres = symlook_obj1_sysv(req, obj);
5026 else
5027 return (EINVAL);
5028
5029 if (mres == 0) {
5030 if (obj->needed_filtees != NULL) {
5031 res = symlook_obj_load_filtees(req, &req1, obj,
5032 obj->needed_filtees);
5033 if (res == 0) {
5034 req->sym_out = req1.sym_out;
5035 req->defobj_out = req1.defobj_out;
5036 }
5037 return (res);
5038 }
5039 if (obj->needed_aux_filtees != NULL) {
5040 res = symlook_obj_load_filtees(req, &req1, obj,
5041 obj->needed_aux_filtees);
5042 if (res == 0) {
5043 req->sym_out = req1.sym_out;
5044 req->defobj_out = req1.defobj_out;
5045 return (res);
5046 }
5047 }
5048 }
5049 return (mres);
5050 }
5051
5052 /* Symbol match routine common to both hash functions */
5053 static bool
matched_symbol(SymLook * req,const Obj_Entry * obj,Sym_Match_Result * result,const unsigned long symnum)5054 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
5055 const unsigned long symnum)
5056 {
5057 Elf_Versym verndx;
5058 const Elf_Sym *symp;
5059 const char *strp;
5060
5061 symp = obj->symtab + symnum;
5062 strp = obj->strtab + symp->st_name;
5063
5064 switch (ELF_ST_TYPE(symp->st_info)) {
5065 case STT_FUNC:
5066 case STT_NOTYPE:
5067 case STT_OBJECT:
5068 case STT_COMMON:
5069 case STT_GNU_IFUNC:
5070 if (symp->st_value == 0)
5071 return (false);
5072 /* fallthrough */
5073 case STT_TLS:
5074 if (symp->st_shndx != SHN_UNDEF)
5075 break;
5076 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
5077 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
5078 break;
5079 /* fallthrough */
5080 default:
5081 return (false);
5082 }
5083 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
5084 return (false);
5085
5086 if (req->ventry == NULL) {
5087 if (obj->versyms != NULL) {
5088 verndx = VER_NDX(obj->versyms[symnum]);
5089 if (verndx > obj->vernum) {
5090 _rtld_error(
5091 "%s: symbol %s references wrong version %d",
5092 obj->path, obj->strtab + symnum, verndx);
5093 return (false);
5094 }
5095 /*
5096 * If we are not called from dlsym (i.e. this
5097 * is a normal relocation from unversioned
5098 * binary), accept the symbol immediately if
5099 * it happens to have first version after this
5100 * shared object became versioned. Otherwise,
5101 * if symbol is versioned and not hidden,
5102 * remember it. If it is the only symbol with
5103 * this name exported by the shared object, it
5104 * will be returned as a match by the calling
5105 * function. If symbol is global (verndx < 2)
5106 * accept it unconditionally.
5107 */
5108 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
5109 verndx == VER_NDX_GIVEN) {
5110 result->sym_out = symp;
5111 return (true);
5112 } else if (verndx >= VER_NDX_GIVEN) {
5113 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) ==
5114 0) {
5115 if (result->vsymp == NULL)
5116 result->vsymp = symp;
5117 result->vcount++;
5118 }
5119 return (false);
5120 }
5121 }
5122 result->sym_out = symp;
5123 return (true);
5124 }
5125 if (obj->versyms == NULL) {
5126 if (object_match_name(obj, req->ventry->name)) {
5127 _rtld_error(
5128 "%s: object %s should provide version %s for symbol %s",
5129 obj_rtld.path, obj->path, req->ventry->name,
5130 obj->strtab + symnum);
5131 return (false);
5132 }
5133 } else {
5134 verndx = VER_NDX(obj->versyms[symnum]);
5135 if (verndx > obj->vernum) {
5136 _rtld_error("%s: symbol %s references wrong version %d",
5137 obj->path, obj->strtab + symnum, verndx);
5138 return (false);
5139 }
5140 if (obj->vertab[verndx].hash != req->ventry->hash ||
5141 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
5142 /*
5143 * Version does not match. Look if this is a
5144 * global symbol and if it is not hidden. If
5145 * global symbol (verndx < 2) is available,
5146 * use it. Do not return symbol if we are
5147 * called by dlvsym, because dlvsym looks for
5148 * a specific version and default one is not
5149 * what dlvsym wants.
5150 */
5151 if ((req->flags & SYMLOOK_DLSYM) ||
5152 (verndx >= VER_NDX_GIVEN) ||
5153 (obj->versyms[symnum] & VER_NDX_HIDDEN))
5154 return (false);
5155 }
5156 }
5157 result->sym_out = symp;
5158 return (true);
5159 }
5160
5161 /*
5162 * Search for symbol using SysV hash function.
5163 * obj->buckets is known not to be NULL at this point; the test for this was
5164 * performed with the obj->valid_hash_sysv assignment.
5165 */
5166 static int
symlook_obj1_sysv(SymLook * req,const Obj_Entry * obj)5167 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
5168 {
5169 unsigned long symnum;
5170 Sym_Match_Result matchres;
5171
5172 matchres.sym_out = NULL;
5173 matchres.vsymp = NULL;
5174 matchres.vcount = 0;
5175
5176 for (symnum = obj->buckets[req->hash % obj->nbuckets];
5177 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
5178 if (symnum >= obj->nchains)
5179 return (ESRCH); /* Bad object */
5180
5181 if (matched_symbol(req, obj, &matchres, symnum)) {
5182 req->sym_out = matchres.sym_out;
5183 req->defobj_out = obj;
5184 return (0);
5185 }
5186 }
5187 if (matchres.vcount == 1) {
5188 req->sym_out = matchres.vsymp;
5189 req->defobj_out = obj;
5190 return (0);
5191 }
5192 return (ESRCH);
5193 }
5194
5195 /* Search for symbol using GNU hash function */
5196 static int
symlook_obj1_gnu(SymLook * req,const Obj_Entry * obj)5197 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
5198 {
5199 Elf_Addr bloom_word;
5200 const Elf32_Word *hashval;
5201 Elf32_Word bucket;
5202 Sym_Match_Result matchres;
5203 unsigned int h1, h2;
5204 unsigned long symnum;
5205
5206 matchres.sym_out = NULL;
5207 matchres.vsymp = NULL;
5208 matchres.vcount = 0;
5209
5210 /* Pick right bitmask word from Bloom filter array */
5211 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
5212 obj->maskwords_bm_gnu];
5213
5214 /* Calculate modulus word size of gnu hash and its derivative */
5215 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
5216 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
5217
5218 /* Filter out the "definitely not in set" queries */
5219 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
5220 return (ESRCH);
5221
5222 /* Locate hash chain and corresponding value element*/
5223 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
5224 if (bucket == 0)
5225 return (ESRCH);
5226 hashval = &obj->chain_zero_gnu[bucket];
5227 do {
5228 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
5229 symnum = hashval - obj->chain_zero_gnu;
5230 if (matched_symbol(req, obj, &matchres, symnum)) {
5231 req->sym_out = matchres.sym_out;
5232 req->defobj_out = obj;
5233 return (0);
5234 }
5235 }
5236 } while ((*hashval++ & 1) == 0);
5237 if (matchres.vcount == 1) {
5238 req->sym_out = matchres.vsymp;
5239 req->defobj_out = obj;
5240 return (0);
5241 }
5242 return (ESRCH);
5243 }
5244
5245 static void
trace_calc_fmts(const char ** main_local,const char ** fmt1,const char ** fmt2)5246 trace_calc_fmts(const char **main_local, const char **fmt1, const char **fmt2)
5247 {
5248 *main_local = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_PROGNAME);
5249 if (*main_local == NULL)
5250 *main_local = "";
5251
5252 *fmt1 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT1);
5253 if (*fmt1 == NULL)
5254 *fmt1 = "\t%o => %p (%x)\n";
5255
5256 *fmt2 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT2);
5257 if (*fmt2 == NULL)
5258 *fmt2 = "\t%o (%x)\n";
5259 }
5260
5261 static void
trace_print_obj(Obj_Entry * obj,const char * name,const char * path,const char * main_local,const char * fmt1,const char * fmt2)5262 trace_print_obj(Obj_Entry *obj, const char *name, const char *path,
5263 const char *main_local, const char *fmt1, const char *fmt2)
5264 {
5265 const char *fmt;
5266 int c;
5267
5268 if (fmt1 == NULL)
5269 fmt = fmt2;
5270 else
5271 /* XXX bogus */
5272 fmt = strncmp(name, "lib", 3) == 0 ? fmt1 : fmt2;
5273
5274 while ((c = *fmt++) != '\0') {
5275 switch (c) {
5276 default:
5277 rtld_putchar(c);
5278 continue;
5279 case '\\':
5280 switch (c = *fmt) {
5281 case '\0':
5282 continue;
5283 case 'n':
5284 rtld_putchar('\n');
5285 break;
5286 case 't':
5287 rtld_putchar('\t');
5288 break;
5289 }
5290 break;
5291 case '%':
5292 switch (c = *fmt) {
5293 case '\0':
5294 continue;
5295 case '%':
5296 default:
5297 rtld_putchar(c);
5298 break;
5299 case 'A':
5300 rtld_putstr(main_local);
5301 break;
5302 case 'a':
5303 rtld_putstr(obj_main->path);
5304 break;
5305 case 'o':
5306 rtld_putstr(name);
5307 break;
5308 case 'p':
5309 rtld_putstr(path);
5310 break;
5311 case 'x':
5312 rtld_printf("%p",
5313 obj != NULL ? obj->mapbase : NULL);
5314 break;
5315 }
5316 break;
5317 }
5318 ++fmt;
5319 }
5320 }
5321
5322 static void
trace_loaded_objects(Obj_Entry * obj,bool show_preload)5323 trace_loaded_objects(Obj_Entry *obj, bool show_preload)
5324 {
5325 const char *fmt1, *fmt2, *main_local;
5326 const char *name, *path;
5327 bool first_spurious, list_containers;
5328
5329 trace_calc_fmts(&main_local, &fmt1, &fmt2);
5330 list_containers = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_ALL) != NULL;
5331
5332 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
5333 Needed_Entry *needed;
5334
5335 if (obj->marker)
5336 continue;
5337 if (list_containers && obj->needed != NULL)
5338 rtld_printf("%s:\n", obj->path);
5339 for (needed = obj->needed; needed; needed = needed->next) {
5340 if (needed->obj != NULL) {
5341 if (needed->obj->traced && !list_containers)
5342 continue;
5343 needed->obj->traced = true;
5344 path = needed->obj->path;
5345 } else
5346 path = "not found";
5347
5348 name = obj->strtab + needed->name;
5349 trace_print_obj(needed->obj, name, path, main_local,
5350 fmt1, fmt2);
5351 }
5352 }
5353
5354 if (show_preload) {
5355 if (ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT2) == NULL)
5356 fmt2 = "\t%p (%x)\n";
5357 first_spurious = true;
5358
5359 TAILQ_FOREACH(obj, &obj_list, next) {
5360 if (obj->marker || obj == obj_main || obj->traced)
5361 continue;
5362
5363 if (list_containers && first_spurious) {
5364 rtld_printf("[preloaded]\n");
5365 first_spurious = false;
5366 }
5367
5368 Name_Entry *fname = STAILQ_FIRST(&obj->names);
5369 name = fname == NULL ? "<unknown>" : fname->name;
5370 trace_print_obj(obj, name, obj->path, main_local, NULL,
5371 fmt2);
5372 }
5373 }
5374 }
5375
5376 /*
5377 * Unload a dlopened object and its dependencies from memory and from
5378 * our data structures. It is assumed that the DAG rooted in the
5379 * object has already been unreferenced, and that the object has a
5380 * reference count of 0.
5381 */
5382 static void
unload_object(Obj_Entry * root,RtldLockState * lockstate)5383 unload_object(Obj_Entry *root, RtldLockState *lockstate)
5384 {
5385 Obj_Entry marker, *obj, *next;
5386
5387 assert(root->refcount == 0);
5388
5389 /*
5390 * Pass over the DAG removing unreferenced objects from
5391 * appropriate lists.
5392 */
5393 unlink_object(root);
5394
5395 /* Unmap all objects that are no longer referenced. */
5396 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) {
5397 next = TAILQ_NEXT(obj, next);
5398 if (obj->marker || obj->refcount != 0)
5399 continue;
5400 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize,
5401 0, obj->path);
5402 dbg("unloading \"%s\"", obj->path);
5403 /*
5404 * Unlink the object now to prevent new references from
5405 * being acquired while the bind lock is dropped in
5406 * recursive dlclose() invocations.
5407 */
5408 TAILQ_REMOVE(&obj_list, obj, next);
5409 obj_count--;
5410
5411 if (obj->filtees_loaded) {
5412 if (next != NULL) {
5413 init_marker(&marker);
5414 TAILQ_INSERT_BEFORE(next, &marker, next);
5415 unload_filtees(obj, lockstate);
5416 next = TAILQ_NEXT(&marker, next);
5417 TAILQ_REMOVE(&obj_list, &marker, next);
5418 } else
5419 unload_filtees(obj, lockstate);
5420 }
5421 release_object(obj);
5422 }
5423 }
5424
5425 static void
unlink_object(Obj_Entry * root)5426 unlink_object(Obj_Entry *root)
5427 {
5428 Objlist_Entry *elm;
5429
5430 if (root->refcount == 0) {
5431 /* Remove the object from the RTLD_GLOBAL list. */
5432 objlist_remove(&list_global, root);
5433
5434 /* Remove the object from all objects' DAG lists. */
5435 STAILQ_FOREACH(elm, &root->dagmembers, link) {
5436 objlist_remove(&elm->obj->dldags, root);
5437 if (elm->obj != root)
5438 unlink_object(elm->obj);
5439 }
5440 }
5441 }
5442
5443 static void
ref_dag(Obj_Entry * root)5444 ref_dag(Obj_Entry *root)
5445 {
5446 Objlist_Entry *elm;
5447
5448 assert(root->dag_inited);
5449 STAILQ_FOREACH(elm, &root->dagmembers, link)
5450 elm->obj->refcount++;
5451 }
5452
5453 static void
unref_dag(Obj_Entry * root)5454 unref_dag(Obj_Entry *root)
5455 {
5456 Objlist_Entry *elm;
5457
5458 assert(root->dag_inited);
5459 STAILQ_FOREACH(elm, &root->dagmembers, link)
5460 elm->obj->refcount--;
5461 }
5462
5463 /*
5464 * Common code for MD __tls_get_addr().
5465 */
5466 static void *
tls_get_addr_slow(struct tcb * tcb,int index,size_t offset,bool locked)5467 tls_get_addr_slow(struct tcb *tcb, int index, size_t offset, bool locked)
5468 {
5469 struct dtv *newdtv, *dtv;
5470 RtldLockState lockstate;
5471 int to_copy;
5472
5473 dtv = tcb->tcb_dtv;
5474 /* Check dtv generation in case new modules have arrived */
5475 if (dtv->dtv_gen != tls_dtv_generation) {
5476 if (!locked)
5477 wlock_acquire(rtld_bind_lock, &lockstate);
5478 newdtv = xcalloc(1, sizeof(struct dtv) + tls_max_index *
5479 sizeof(struct dtv_slot));
5480 to_copy = dtv->dtv_size;
5481 if (to_copy > tls_max_index)
5482 to_copy = tls_max_index;
5483 memcpy(newdtv->dtv_slots, dtv->dtv_slots, to_copy *
5484 sizeof(struct dtv_slot));
5485 newdtv->dtv_gen = tls_dtv_generation;
5486 newdtv->dtv_size = tls_max_index;
5487 free(dtv);
5488 if (!locked)
5489 lock_release(rtld_bind_lock, &lockstate);
5490 dtv = tcb->tcb_dtv = newdtv;
5491 }
5492
5493 /* Dynamically allocate module TLS if necessary */
5494 if (dtv->dtv_slots[index - 1].dtvs_tls == 0) {
5495 /* Signal safe, wlock will block out signals. */
5496 if (!locked)
5497 wlock_acquire(rtld_bind_lock, &lockstate);
5498 if (!dtv->dtv_slots[index - 1].dtvs_tls)
5499 dtv->dtv_slots[index - 1].dtvs_tls =
5500 allocate_module_tls(tcb, index);
5501 if (!locked)
5502 lock_release(rtld_bind_lock, &lockstate);
5503 }
5504 return (dtv->dtv_slots[index - 1].dtvs_tls + offset);
5505 }
5506
5507 void *
tls_get_addr_common(struct tcb * tcb,int index,size_t offset)5508 tls_get_addr_common(struct tcb *tcb, int index, size_t offset)
5509 {
5510 struct dtv *dtv;
5511
5512 dtv = tcb->tcb_dtv;
5513 /* Check dtv generation in case new modules have arrived */
5514 if (__predict_true(dtv->dtv_gen == tls_dtv_generation &&
5515 dtv->dtv_slots[index - 1].dtvs_tls != 0))
5516 return (dtv->dtv_slots[index - 1].dtvs_tls + offset);
5517 return (tls_get_addr_slow(tcb, index, offset, false));
5518 }
5519
5520 static struct tcb *
tcb_from_tcb_list_entry(struct tcb_list_entry * tcbelm)5521 tcb_from_tcb_list_entry(struct tcb_list_entry *tcbelm)
5522 {
5523 #ifdef TLS_VARIANT_I
5524 return ((struct tcb *)((char *)tcbelm - tcb_list_entry_offset));
5525 #else
5526 return ((struct tcb *)((char *)tcbelm + tcb_list_entry_offset));
5527 #endif
5528 }
5529
5530 static struct tcb_list_entry *
tcb_list_entry_from_tcb(struct tcb * tcb)5531 tcb_list_entry_from_tcb(struct tcb *tcb)
5532 {
5533 #ifdef TLS_VARIANT_I
5534 return ((struct tcb_list_entry *)((char *)tcb + tcb_list_entry_offset));
5535 #else
5536 return ((struct tcb_list_entry *)((char *)tcb - tcb_list_entry_offset));
5537 #endif
5538 }
5539
5540 static void
tcb_list_insert(struct tcb * tcb)5541 tcb_list_insert(struct tcb *tcb)
5542 {
5543 struct tcb_list_entry *tcbelm;
5544
5545 tcbelm = tcb_list_entry_from_tcb(tcb);
5546 TAILQ_INSERT_TAIL(&tcb_list, tcbelm, next);
5547 }
5548
5549 static void
tcb_list_remove(struct tcb * tcb)5550 tcb_list_remove(struct tcb *tcb)
5551 {
5552 struct tcb_list_entry *tcbelm;
5553
5554 tcbelm = tcb_list_entry_from_tcb(tcb);
5555 TAILQ_REMOVE(&tcb_list, tcbelm, next);
5556 }
5557
5558 #ifdef TLS_VARIANT_I
5559
5560 /*
5561 * Return pointer to allocated TLS block
5562 */
5563 static void *
get_tls_block_ptr(void * tcb,size_t tcbsize)5564 get_tls_block_ptr(void *tcb, size_t tcbsize)
5565 {
5566 size_t extra_size, post_size, pre_size, tls_block_size;
5567 size_t tls_init_align;
5568
5569 tls_init_align = MAX(obj_main->tlsalign, 1);
5570
5571 /* Compute fragments sizes. */
5572 extra_size = tcbsize - TLS_TCB_SIZE;
5573 post_size = calculate_tls_post_size(tls_init_align);
5574 tls_block_size = tcbsize + post_size;
5575 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size;
5576
5577 return ((char *)tcb - pre_size - extra_size);
5578 }
5579
5580 /*
5581 * Allocate Static TLS using the Variant I method.
5582 *
5583 * For details on the layout, see lib/libc/gen/tls.c.
5584 *
5585 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as
5586 * it is based on tls_last_offset, and TLS offsets here are really TCB
5587 * offsets, whereas libc's tls_static_space is just the executable's static
5588 * TLS segment.
5589 *
5590 * NB: This differs from NetBSD's ld.elf_so, where TLS offsets are relative to
5591 * the end of the TCB.
5592 */
5593 void *
allocate_tls(Obj_Entry * objs,void * oldtcb,size_t tcbsize,size_t tcbalign)5594 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
5595 {
5596 Obj_Entry *obj;
5597 char *tls_block;
5598 struct dtv *dtv;
5599 struct tcb *tcb;
5600 char *addr;
5601 size_t i;
5602 size_t extra_size, maxalign, post_size, pre_size, tls_block_size;
5603 size_t tls_init_align, tls_init_offset, tls_bss_offset;
5604
5605 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
5606 return (oldtcb);
5607
5608 assert(tcbsize >= TLS_TCB_SIZE);
5609 maxalign = MAX(tcbalign, tls_static_max_align);
5610 tls_init_align = MAX(obj_main->tlsalign, 1);
5611
5612 /* Compute fragments sizes. */
5613 extra_size = tcbsize - TLS_TCB_SIZE;
5614 post_size = calculate_tls_post_size(tls_init_align);
5615 tls_block_size = tcbsize + post_size;
5616 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size;
5617 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE -
5618 post_size;
5619
5620 /* Allocate whole TLS block */
5621 tls_block = xmalloc_aligned(tls_block_size, maxalign, 0);
5622 tcb = (struct tcb *)(tls_block + pre_size + extra_size);
5623
5624 if (oldtcb != NULL) {
5625 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize),
5626 tls_static_space);
5627 free(get_tls_block_ptr(oldtcb, tcbsize));
5628
5629 /* Adjust the DTV. */
5630 dtv = tcb->tcb_dtv;
5631 for (i = 0; i < dtv->dtv_size; i++) {
5632 if ((uintptr_t)dtv->dtv_slots[i].dtvs_tls >=
5633 (uintptr_t)oldtcb &&
5634 (uintptr_t)dtv->dtv_slots[i].dtvs_tls <
5635 (uintptr_t)oldtcb + tls_static_space) {
5636 dtv->dtv_slots[i].dtvs_tls = (char *)tcb +
5637 (dtv->dtv_slots[i].dtvs_tls -
5638 (char *)oldtcb);
5639 }
5640 }
5641 } else {
5642 dtv = xcalloc(1, sizeof(struct dtv) + tls_max_index *
5643 sizeof(struct dtv_slot));
5644 tcb->tcb_dtv = dtv;
5645 dtv->dtv_gen = tls_dtv_generation;
5646 dtv->dtv_size = tls_max_index;
5647
5648 for (obj = globallist_curr(objs); obj != NULL;
5649 obj = globallist_next(obj)) {
5650 if (obj->tlsoffset == 0)
5651 continue;
5652 tls_init_offset = obj->tlspoffset & (obj->tlsalign - 1);
5653 addr = (char *)tcb + obj->tlsoffset;
5654 if (tls_init_offset > 0)
5655 memset(addr, 0, tls_init_offset);
5656 if (obj->tlsinitsize > 0) {
5657 memcpy(addr + tls_init_offset, obj->tlsinit,
5658 obj->tlsinitsize);
5659 }
5660 if (obj->tlssize > obj->tlsinitsize) {
5661 tls_bss_offset = tls_init_offset +
5662 obj->tlsinitsize;
5663 memset(addr + tls_bss_offset, 0,
5664 obj->tlssize - tls_bss_offset);
5665 }
5666 dtv->dtv_slots[obj->tlsindex - 1].dtvs_tls = addr;
5667 }
5668 }
5669
5670 tcb_list_insert(tcb);
5671 return (tcb);
5672 }
5673
5674 void
free_tls(void * tcb,size_t tcbsize,size_t tcbalign __unused)5675 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused)
5676 {
5677 struct dtv *dtv;
5678 uintptr_t tlsstart, tlsend;
5679 size_t post_size;
5680 size_t i, tls_init_align __unused;
5681
5682 tcb_list_remove(tcb);
5683
5684 assert(tcbsize >= TLS_TCB_SIZE);
5685 tls_init_align = MAX(obj_main->tlsalign, 1);
5686
5687 /* Compute fragments sizes. */
5688 post_size = calculate_tls_post_size(tls_init_align);
5689
5690 tlsstart = (uintptr_t)tcb + TLS_TCB_SIZE + post_size;
5691 tlsend = (uintptr_t)tcb + tls_static_space;
5692
5693 dtv = ((struct tcb *)tcb)->tcb_dtv;
5694 for (i = 0; i < dtv->dtv_size; i++) {
5695 if (dtv->dtv_slots[i].dtvs_tls != NULL &&
5696 ((uintptr_t)dtv->dtv_slots[i].dtvs_tls < tlsstart ||
5697 (uintptr_t)dtv->dtv_slots[i].dtvs_tls >= tlsend)) {
5698 free(dtv->dtv_slots[i].dtvs_tls);
5699 }
5700 }
5701 free(dtv);
5702 free(get_tls_block_ptr(tcb, tcbsize));
5703 }
5704
5705 #endif /* TLS_VARIANT_I */
5706
5707 #ifdef TLS_VARIANT_II
5708
5709 /*
5710 * Allocate Static TLS using the Variant II method.
5711 */
5712 void *
allocate_tls(Obj_Entry * objs,void * oldtcb,size_t tcbsize,size_t tcbalign)5713 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
5714 {
5715 Obj_Entry *obj;
5716 size_t size, ralign;
5717 char *tls_block;
5718 struct dtv *dtv, *olddtv;
5719 struct tcb *tcb;
5720 char *addr;
5721 size_t i;
5722
5723 ralign = tcbalign;
5724 if (tls_static_max_align > ralign)
5725 ralign = tls_static_max_align;
5726 size = roundup(tls_static_space, ralign) + roundup(tcbsize, ralign);
5727
5728 assert(tcbsize >= 2 * sizeof(uintptr_t));
5729 tls_block = xmalloc_aligned(size, ralign, 0 /* XXX */);
5730 dtv = xcalloc(1, sizeof(struct dtv) + tls_max_index *
5731 sizeof(struct dtv_slot));
5732
5733 tcb = (struct tcb *)(tls_block + roundup(tls_static_space, ralign));
5734 tcb->tcb_self = tcb;
5735 tcb->tcb_dtv = dtv;
5736
5737 dtv->dtv_gen = tls_dtv_generation;
5738 dtv->dtv_size = tls_max_index;
5739
5740 if (oldtcb != NULL) {
5741 /*
5742 * Copy the static TLS block over whole.
5743 */
5744 memcpy((char *)tcb - tls_static_space,
5745 (const char *)oldtcb - tls_static_space,
5746 tls_static_space);
5747
5748 /*
5749 * If any dynamic TLS blocks have been created tls_get_addr(),
5750 * move them over.
5751 */
5752 olddtv = ((struct tcb *)oldtcb)->tcb_dtv;
5753 for (i = 0; i < olddtv->dtv_size; i++) {
5754 if ((uintptr_t)olddtv->dtv_slots[i].dtvs_tls <
5755 (uintptr_t)oldtcb - size ||
5756 (uintptr_t)olddtv->dtv_slots[i].dtvs_tls >
5757 (uintptr_t)oldtcb) {
5758 dtv->dtv_slots[i].dtvs_tls =
5759 olddtv->dtv_slots[i].dtvs_tls;
5760 olddtv->dtv_slots[i].dtvs_tls = NULL;
5761 }
5762 }
5763
5764 /*
5765 * We assume that this block was the one we created with
5766 * allocate_initial_tls().
5767 */
5768 free_tls(oldtcb, 2 * sizeof(uintptr_t), sizeof(uintptr_t));
5769 } else {
5770 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
5771 if (obj->marker || obj->tlsoffset == 0)
5772 continue;
5773 addr = (char *)tcb - obj->tlsoffset;
5774 memset(addr + obj->tlsinitsize, 0, obj->tlssize -
5775 obj->tlsinitsize);
5776 if (obj->tlsinit) {
5777 memcpy(addr, obj->tlsinit, obj->tlsinitsize);
5778 obj->static_tls_copied = true;
5779 }
5780 dtv->dtv_slots[obj->tlsindex - 1].dtvs_tls = addr;
5781 }
5782 }
5783
5784 tcb_list_insert(tcb);
5785 return (tcb);
5786 }
5787
5788 void
free_tls(void * tcb,size_t tcbsize __unused,size_t tcbalign)5789 free_tls(void *tcb, size_t tcbsize __unused, size_t tcbalign)
5790 {
5791 struct dtv *dtv;
5792 size_t size, ralign;
5793 size_t i;
5794 uintptr_t tlsstart, tlsend;
5795
5796 tcb_list_remove(tcb);
5797
5798 /*
5799 * Figure out the size of the initial TLS block so that we can
5800 * find stuff which ___tls_get_addr() allocated dynamically.
5801 */
5802 ralign = tcbalign;
5803 if (tls_static_max_align > ralign)
5804 ralign = tls_static_max_align;
5805 size = roundup(tls_static_space, ralign);
5806
5807 dtv = ((struct tcb *)tcb)->tcb_dtv;
5808 tlsend = (uintptr_t)tcb;
5809 tlsstart = tlsend - size;
5810 for (i = 0; i < dtv->dtv_size; i++) {
5811 if (dtv->dtv_slots[i].dtvs_tls != NULL &&
5812 ((uintptr_t)dtv->dtv_slots[i].dtvs_tls < tlsstart ||
5813 (uintptr_t)dtv->dtv_slots[i].dtvs_tls > tlsend)) {
5814 free(dtv->dtv_slots[i].dtvs_tls);
5815 }
5816 }
5817
5818 free((void *)tlsstart);
5819 free(dtv);
5820 }
5821
5822 #endif /* TLS_VARIANT_II */
5823
5824 /*
5825 * Allocate TLS block for module with given index.
5826 */
5827 void *
allocate_module_tls(struct tcb * tcb,int index)5828 allocate_module_tls(struct tcb *tcb, int index)
5829 {
5830 Obj_Entry *obj;
5831 char *p;
5832
5833 TAILQ_FOREACH(obj, &obj_list, next) {
5834 if (obj->marker)
5835 continue;
5836 if (obj->tlsindex == index)
5837 break;
5838 }
5839 if (obj == NULL) {
5840 _rtld_error("Can't find module with TLS index %d", index);
5841 rtld_die();
5842 }
5843
5844 if (obj->tls_static) {
5845 #ifdef TLS_VARIANT_I
5846 p = (char *)tcb + obj->tlsoffset;
5847 #else
5848 p = (char *)tcb - obj->tlsoffset;
5849 #endif
5850 return (p);
5851 }
5852
5853 obj->tls_dynamic = true;
5854
5855 p = xmalloc_aligned(obj->tlssize, obj->tlsalign, obj->tlspoffset);
5856 memcpy(p, obj->tlsinit, obj->tlsinitsize);
5857 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
5858 return (p);
5859 }
5860
5861 static bool
allocate_tls_offset_common(size_t * offp,size_t tlssize,size_t tlsalign,size_t tlspoffset __unused)5862 allocate_tls_offset_common(size_t *offp, size_t tlssize, size_t tlsalign,
5863 size_t tlspoffset __unused)
5864 {
5865 size_t off;
5866
5867 if (tls_last_offset == 0)
5868 off = calculate_first_tls_offset(tlssize, tlsalign,
5869 tlspoffset);
5870 else
5871 off = calculate_tls_offset(tls_last_offset, tls_last_size,
5872 tlssize, tlsalign, tlspoffset);
5873
5874 *offp = off;
5875 #ifdef TLS_VARIANT_I
5876 off += tlssize;
5877 #endif
5878
5879 /*
5880 * If we have already fixed the size of the static TLS block, we
5881 * must stay within that size. When allocating the static TLS, we
5882 * leave a small amount of space spare to be used for dynamically
5883 * loading modules which use static TLS.
5884 */
5885 if (tls_static_space != 0) {
5886 if (off > tls_static_space)
5887 return (false);
5888 } else if (tlsalign > tls_static_max_align) {
5889 tls_static_max_align = tlsalign;
5890 }
5891
5892 tls_last_offset = off;
5893 tls_last_size = tlssize;
5894
5895 return (true);
5896 }
5897
5898 bool
allocate_tls_offset(Obj_Entry * obj)5899 allocate_tls_offset(Obj_Entry *obj)
5900 {
5901 if (obj->tls_dynamic)
5902 return (false);
5903
5904 if (obj->tls_static)
5905 return (true);
5906
5907 if (obj->tlssize == 0) {
5908 obj->tls_static = true;
5909 return (true);
5910 }
5911
5912 if (!allocate_tls_offset_common(&obj->tlsoffset, obj->tlssize,
5913 obj->tlsalign, obj->tlspoffset))
5914 return (false);
5915
5916 obj->tls_static = true;
5917
5918 return (true);
5919 }
5920
5921 void
free_tls_offset(Obj_Entry * obj)5922 free_tls_offset(Obj_Entry *obj)
5923 {
5924 /*
5925 * If we were the last thing to allocate out of the static TLS
5926 * block, we give our space back to the 'allocator'. This is a
5927 * simplistic workaround to allow libGL.so.1 to be loaded and
5928 * unloaded multiple times.
5929 */
5930 size_t off = obj->tlsoffset;
5931
5932 #ifdef TLS_VARIANT_I
5933 off += obj->tlssize;
5934 #endif
5935 if (off == tls_last_offset) {
5936 tls_last_offset -= obj->tlssize;
5937 tls_last_size = 0;
5938 }
5939 }
5940
5941 void *
_rtld_allocate_tls(void * oldtcb,size_t tcbsize,size_t tcbalign)5942 _rtld_allocate_tls(void *oldtcb, size_t tcbsize, size_t tcbalign)
5943 {
5944 void *ret;
5945 RtldLockState lockstate;
5946
5947 wlock_acquire(rtld_bind_lock, &lockstate);
5948 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtcb,
5949 tcbsize, tcbalign);
5950 lock_release(rtld_bind_lock, &lockstate);
5951 return (ret);
5952 }
5953
5954 void
_rtld_free_tls(void * tcb,size_t tcbsize,size_t tcbalign)5955 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
5956 {
5957 RtldLockState lockstate;
5958
5959 wlock_acquire(rtld_bind_lock, &lockstate);
5960 free_tls(tcb, tcbsize, tcbalign);
5961 lock_release(rtld_bind_lock, &lockstate);
5962 }
5963
5964 static void
object_add_name(Obj_Entry * obj,const char * name)5965 object_add_name(Obj_Entry *obj, const char *name)
5966 {
5967 Name_Entry *entry;
5968 size_t len;
5969
5970 len = strlen(name);
5971 entry = malloc(sizeof(Name_Entry) + len);
5972
5973 if (entry != NULL) {
5974 strcpy(entry->name, name);
5975 STAILQ_INSERT_TAIL(&obj->names, entry, link);
5976 }
5977 }
5978
5979 static int
object_match_name(const Obj_Entry * obj,const char * name)5980 object_match_name(const Obj_Entry *obj, const char *name)
5981 {
5982 Name_Entry *entry;
5983
5984 STAILQ_FOREACH(entry, &obj->names, link) {
5985 if (strcmp(name, entry->name) == 0)
5986 return (1);
5987 }
5988 return (0);
5989 }
5990
5991 static Obj_Entry *
locate_dependency(const Obj_Entry * obj,const char * name)5992 locate_dependency(const Obj_Entry *obj, const char *name)
5993 {
5994 const Objlist_Entry *entry;
5995 const Needed_Entry *needed;
5996
5997 STAILQ_FOREACH(entry, &list_main, link) {
5998 if (object_match_name(entry->obj, name))
5999 return (entry->obj);
6000 }
6001
6002 for (needed = obj->needed; needed != NULL; needed = needed->next) {
6003 if (strcmp(obj->strtab + needed->name, name) == 0 ||
6004 (needed->obj != NULL && object_match_name(needed->obj,
6005 name))) {
6006 /*
6007 * If there is DT_NEEDED for the name we are looking
6008 * for, we are all set. Note that object might not be
6009 * found if dependency was not loaded yet, so the
6010 * function can return NULL here. This is expected and
6011 * handled properly by the caller.
6012 */
6013 return (needed->obj);
6014 }
6015 }
6016 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
6017 obj->path, name);
6018 rtld_die();
6019 }
6020
6021 static int
check_object_provided_version(Obj_Entry * refobj,const Obj_Entry * depobj,const Elf_Vernaux * vna)6022 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
6023 const Elf_Vernaux *vna)
6024 {
6025 const Elf_Verdef *vd;
6026 const char *vername;
6027
6028 vername = refobj->strtab + vna->vna_name;
6029 vd = depobj->verdef;
6030 if (vd == NULL) {
6031 _rtld_error("%s: version %s required by %s not defined",
6032 depobj->path, vername, refobj->path);
6033 return (-1);
6034 }
6035 for (;;) {
6036 if (vd->vd_version != VER_DEF_CURRENT) {
6037 _rtld_error(
6038 "%s: Unsupported version %d of Elf_Verdef entry",
6039 depobj->path, vd->vd_version);
6040 return (-1);
6041 }
6042 if (vna->vna_hash == vd->vd_hash) {
6043 const Elf_Verdaux *aux =
6044 (const Elf_Verdaux *)((const char *)vd +
6045 vd->vd_aux);
6046 if (strcmp(vername, depobj->strtab + aux->vda_name) ==
6047 0)
6048 return (0);
6049 }
6050 if (vd->vd_next == 0)
6051 break;
6052 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
6053 }
6054 if (vna->vna_flags & VER_FLG_WEAK)
6055 return (0);
6056 _rtld_error("%s: version %s required by %s not found", depobj->path,
6057 vername, refobj->path);
6058 return (-1);
6059 }
6060
6061 static int
rtld_verify_object_versions(Obj_Entry * obj)6062 rtld_verify_object_versions(Obj_Entry *obj)
6063 {
6064 const Elf_Verneed *vn;
6065 const Elf_Verdef *vd;
6066 const Elf_Verdaux *vda;
6067 const Elf_Vernaux *vna;
6068 const Obj_Entry *depobj;
6069 int maxvernum, vernum;
6070
6071 if (obj->ver_checked)
6072 return (0);
6073 obj->ver_checked = true;
6074
6075 maxvernum = 0;
6076 /*
6077 * Walk over defined and required version records and figure out
6078 * max index used by any of them. Do very basic sanity checking
6079 * while there.
6080 */
6081 vn = obj->verneed;
6082 while (vn != NULL) {
6083 if (vn->vn_version != VER_NEED_CURRENT) {
6084 _rtld_error(
6085 "%s: Unsupported version %d of Elf_Verneed entry",
6086 obj->path, vn->vn_version);
6087 return (-1);
6088 }
6089 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux);
6090 for (;;) {
6091 vernum = VER_NEED_IDX(vna->vna_other);
6092 if (vernum > maxvernum)
6093 maxvernum = vernum;
6094 if (vna->vna_next == 0)
6095 break;
6096 vna = (const Elf_Vernaux *)((const char *)vna +
6097 vna->vna_next);
6098 }
6099 if (vn->vn_next == 0)
6100 break;
6101 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next);
6102 }
6103
6104 vd = obj->verdef;
6105 while (vd != NULL) {
6106 if (vd->vd_version != VER_DEF_CURRENT) {
6107 _rtld_error(
6108 "%s: Unsupported version %d of Elf_Verdef entry",
6109 obj->path, vd->vd_version);
6110 return (-1);
6111 }
6112 vernum = VER_DEF_IDX(vd->vd_ndx);
6113 if (vernum > maxvernum)
6114 maxvernum = vernum;
6115 if (vd->vd_next == 0)
6116 break;
6117 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
6118 }
6119
6120 if (maxvernum == 0)
6121 return (0);
6122
6123 /*
6124 * Store version information in array indexable by version index.
6125 * Verify that object version requirements are satisfied along the
6126 * way.
6127 */
6128 obj->vernum = maxvernum + 1;
6129 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
6130
6131 vd = obj->verdef;
6132 while (vd != NULL) {
6133 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
6134 vernum = VER_DEF_IDX(vd->vd_ndx);
6135 assert(vernum <= maxvernum);
6136 vda = (const Elf_Verdaux *)((const char *)vd +
6137 vd->vd_aux);
6138 obj->vertab[vernum].hash = vd->vd_hash;
6139 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
6140 obj->vertab[vernum].file = NULL;
6141 obj->vertab[vernum].flags = 0;
6142 }
6143 if (vd->vd_next == 0)
6144 break;
6145 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
6146 }
6147
6148 vn = obj->verneed;
6149 while (vn != NULL) {
6150 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
6151 if (depobj == NULL)
6152 return (-1);
6153 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux);
6154 for (;;) {
6155 if (check_object_provided_version(obj, depobj, vna))
6156 return (-1);
6157 vernum = VER_NEED_IDX(vna->vna_other);
6158 assert(vernum <= maxvernum);
6159 obj->vertab[vernum].hash = vna->vna_hash;
6160 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
6161 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
6162 obj->vertab[vernum].flags = (vna->vna_other &
6163 VER_NEED_HIDDEN) != 0 ? VER_INFO_HIDDEN : 0;
6164 if (vna->vna_next == 0)
6165 break;
6166 vna = (const Elf_Vernaux *)((const char *)vna +
6167 vna->vna_next);
6168 }
6169 if (vn->vn_next == 0)
6170 break;
6171 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next);
6172 }
6173 return (0);
6174 }
6175
6176 static int
rtld_verify_versions(const Objlist * objlist)6177 rtld_verify_versions(const Objlist *objlist)
6178 {
6179 Objlist_Entry *entry;
6180 int rc;
6181
6182 rc = 0;
6183 STAILQ_FOREACH(entry, objlist, link) {
6184 /*
6185 * Skip dummy objects or objects that have their version
6186 * requirements already checked.
6187 */
6188 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
6189 continue;
6190 if (rtld_verify_object_versions(entry->obj) == -1) {
6191 rc = -1;
6192 if (ld_tracing == NULL)
6193 break;
6194 }
6195 }
6196 if (rc == 0 || ld_tracing != NULL)
6197 rc = rtld_verify_object_versions(&obj_rtld);
6198 return (rc);
6199 }
6200
6201 const Ver_Entry *
fetch_ventry(const Obj_Entry * obj,unsigned long symnum)6202 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
6203 {
6204 Elf_Versym vernum;
6205
6206 if (obj->vertab) {
6207 vernum = VER_NDX(obj->versyms[symnum]);
6208 if (vernum >= obj->vernum) {
6209 _rtld_error("%s: symbol %s has wrong verneed value %d",
6210 obj->path, obj->strtab + symnum, vernum);
6211 } else if (obj->vertab[vernum].hash != 0) {
6212 return (&obj->vertab[vernum]);
6213 }
6214 }
6215 return (NULL);
6216 }
6217
6218 int
_rtld_get_stack_prot(void)6219 _rtld_get_stack_prot(void)
6220 {
6221 return (stack_prot);
6222 }
6223
6224 int
_rtld_is_dlopened(void * arg)6225 _rtld_is_dlopened(void *arg)
6226 {
6227 Obj_Entry *obj;
6228 RtldLockState lockstate;
6229 int res;
6230
6231 rlock_acquire(rtld_bind_lock, &lockstate);
6232 obj = dlcheck(arg);
6233 if (obj == NULL)
6234 obj = obj_from_addr(arg);
6235 if (obj == NULL) {
6236 _rtld_error("No shared object contains address");
6237 lock_release(rtld_bind_lock, &lockstate);
6238 return (-1);
6239 }
6240 res = obj->dlopened ? 1 : 0;
6241 lock_release(rtld_bind_lock, &lockstate);
6242 return (res);
6243 }
6244
6245 static int
obj_remap_relro(Obj_Entry * obj,int prot)6246 obj_remap_relro(Obj_Entry *obj, int prot)
6247 {
6248 const Elf_Phdr *ph;
6249 caddr_t relro_page;
6250 size_t relro_size;
6251
6252 for (ph = obj->phdr; ph < obj->phdr + obj->phnum; ph++) {
6253 if (ph->p_type != PT_GNU_RELRO)
6254 continue;
6255 relro_page = obj->relocbase + rtld_trunc_page(ph->p_vaddr);
6256 relro_size = rtld_round_page(ph->p_vaddr + ph->p_memsz) -
6257 rtld_trunc_page(ph->p_vaddr);
6258 if (mprotect(relro_page, relro_size, prot) == -1) {
6259 _rtld_error(
6260 "%s: Cannot set relro protection to %#x: %s",
6261 obj->path, prot, rtld_strerror(errno));
6262 return (-1);
6263 }
6264 break;
6265 }
6266 return (0);
6267 }
6268
6269 static int
obj_disable_relro(Obj_Entry * obj)6270 obj_disable_relro(Obj_Entry *obj)
6271 {
6272 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE));
6273 }
6274
6275 static int
obj_enforce_relro(Obj_Entry * obj)6276 obj_enforce_relro(Obj_Entry *obj)
6277 {
6278 return (obj_remap_relro(obj, PROT_READ));
6279 }
6280
6281 static void
map_stacks_exec(RtldLockState * lockstate)6282 map_stacks_exec(RtldLockState *lockstate)
6283 {
6284 void (*thr_map_stacks_exec)(void);
6285
6286 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
6287 return;
6288 thr_map_stacks_exec = (void (*)(void))(
6289 uintptr_t)get_program_var_addr("__pthread_map_stacks_exec",
6290 lockstate);
6291 if (thr_map_stacks_exec != NULL) {
6292 stack_prot |= PROT_EXEC;
6293 thr_map_stacks_exec();
6294 }
6295 }
6296
6297 static void
distribute_static_tls(Objlist * list)6298 distribute_static_tls(Objlist *list)
6299 {
6300 struct tcb_list_entry *tcbelm;
6301 Objlist_Entry *objelm;
6302 struct tcb *tcb;
6303 Obj_Entry *obj;
6304 char *tlsbase;
6305
6306 STAILQ_FOREACH(objelm, list, link) {
6307 obj = objelm->obj;
6308 if (obj->marker || !obj->tls_static || obj->static_tls_copied)
6309 continue;
6310 TAILQ_FOREACH(tcbelm, &tcb_list, next) {
6311 tcb = tcb_from_tcb_list_entry(tcbelm);
6312 #ifdef TLS_VARIANT_I
6313 tlsbase = (char *)tcb + obj->tlsoffset;
6314 #else
6315 tlsbase = (char *)tcb - obj->tlsoffset;
6316 #endif
6317 memcpy(tlsbase, obj->tlsinit, obj->tlsinitsize);
6318 memset(tlsbase + obj->tlsinitsize, 0,
6319 obj->tlssize - obj->tlsinitsize);
6320 }
6321 obj->static_tls_copied = true;
6322 }
6323 }
6324
6325 void
symlook_init(SymLook * dst,const char * name)6326 symlook_init(SymLook *dst, const char *name)
6327 {
6328 bzero(dst, sizeof(*dst));
6329 dst->name = name;
6330 dst->hash = elf_hash(name);
6331 dst->hash_gnu = gnu_hash(name);
6332 }
6333
6334 static void
symlook_init_from_req(SymLook * dst,const SymLook * src)6335 symlook_init_from_req(SymLook *dst, const SymLook *src)
6336 {
6337 dst->name = src->name;
6338 dst->hash = src->hash;
6339 dst->hash_gnu = src->hash_gnu;
6340 dst->ventry = src->ventry;
6341 dst->flags = src->flags;
6342 dst->defobj_out = NULL;
6343 dst->sym_out = NULL;
6344 dst->lockstate = src->lockstate;
6345 dst->donelist_mem = NULL;
6346 }
6347
6348 static int
open_binary_fd(const char * argv0,bool search_in_path,const char ** binpath_res)6349 open_binary_fd(const char *argv0, bool search_in_path, const char **binpath_res)
6350 {
6351 char *binpath, *pathenv, *pe, *res1;
6352 const char *res;
6353 int fd;
6354
6355 binpath = NULL;
6356 res = NULL;
6357 if (search_in_path && strchr(argv0, '/') == NULL) {
6358 binpath = xmalloc(PATH_MAX);
6359 pathenv = getenv("PATH");
6360 if (pathenv == NULL) {
6361 _rtld_error("-p and no PATH environment variable");
6362 rtld_die();
6363 }
6364 pathenv = strdup(pathenv);
6365 if (pathenv == NULL) {
6366 _rtld_error("Cannot allocate memory");
6367 rtld_die();
6368 }
6369 fd = -1;
6370 errno = ENOENT;
6371 while ((pe = strsep(&pathenv, ":")) != NULL) {
6372 if (strlcpy(binpath, pe, PATH_MAX) >= PATH_MAX)
6373 continue;
6374 if (binpath[0] != '\0' &&
6375 strlcat(binpath, "/", PATH_MAX) >= PATH_MAX)
6376 continue;
6377 if (strlcat(binpath, argv0, PATH_MAX) >= PATH_MAX)
6378 continue;
6379 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY);
6380 if (fd != -1 || errno != ENOENT) {
6381 res = binpath;
6382 break;
6383 }
6384 }
6385 free(pathenv);
6386 } else {
6387 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY);
6388 res = argv0;
6389 }
6390
6391 if (fd == -1) {
6392 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno));
6393 rtld_die();
6394 }
6395 if (res != NULL && res[0] != '/') {
6396 res1 = xmalloc(PATH_MAX);
6397 if (realpath(res, res1) != NULL) {
6398 if (res != argv0)
6399 free(__DECONST(char *, res));
6400 res = res1;
6401 } else {
6402 free(res1);
6403 }
6404 }
6405 *binpath_res = res;
6406 return (fd);
6407 }
6408
6409 /*
6410 * Parse a set of command-line arguments.
6411 */
6412 static int
parse_args(char * argv[],int argc,bool * use_pathp,int * fdp,const char ** argv0,bool * dir_ignore)6413 parse_args(char *argv[], int argc, bool *use_pathp, int *fdp,
6414 const char **argv0, bool *dir_ignore)
6415 {
6416 const char *arg;
6417 char machine[64];
6418 size_t sz;
6419 int arglen, fd, i, j, mib[2];
6420 char opt;
6421 bool seen_b, seen_f;
6422
6423 dbg("Parsing command-line arguments");
6424 *use_pathp = false;
6425 *fdp = -1;
6426 *dir_ignore = false;
6427 seen_b = seen_f = false;
6428
6429 for (i = 1; i < argc; i++) {
6430 arg = argv[i];
6431 dbg("argv[%d]: '%s'", i, arg);
6432
6433 /*
6434 * rtld arguments end with an explicit "--" or with the first
6435 * non-prefixed argument.
6436 */
6437 if (strcmp(arg, "--") == 0) {
6438 i++;
6439 break;
6440 }
6441 if (arg[0] != '-')
6442 break;
6443
6444 /*
6445 * All other arguments are single-character options that can
6446 * be combined, so we need to search through `arg` for them.
6447 */
6448 arglen = strlen(arg);
6449 for (j = 1; j < arglen; j++) {
6450 opt = arg[j];
6451 if (opt == 'h') {
6452 print_usage(argv[0]);
6453 _exit(0);
6454 } else if (opt == 'b') {
6455 if (seen_f) {
6456 _rtld_error("Both -b and -f specified");
6457 rtld_die();
6458 }
6459 if (j != arglen - 1) {
6460 _rtld_error("Invalid options: %s", arg);
6461 rtld_die();
6462 }
6463 i++;
6464 *argv0 = argv[i];
6465 seen_b = true;
6466 break;
6467 } else if (opt == 'd') {
6468 *dir_ignore = true;
6469 } else if (opt == 'f') {
6470 if (seen_b) {
6471 _rtld_error("Both -b and -f specified");
6472 rtld_die();
6473 }
6474
6475 /*
6476 * -f XX can be used to specify a
6477 * descriptor for the binary named at
6478 * the command line (i.e., the later
6479 * argument will specify the process
6480 * name but the descriptor is what
6481 * will actually be executed).
6482 *
6483 * -f must be the last option in the
6484 * group, e.g., -abcf <fd>.
6485 */
6486 if (j != arglen - 1) {
6487 _rtld_error("Invalid options: %s", arg);
6488 rtld_die();
6489 }
6490 i++;
6491 fd = parse_integer(argv[i]);
6492 if (fd == -1) {
6493 _rtld_error(
6494 "Invalid file descriptor: '%s'",
6495 argv[i]);
6496 rtld_die();
6497 }
6498 *fdp = fd;
6499 seen_f = true;
6500 break;
6501 } else if (opt == 'o') {
6502 struct ld_env_var_desc *l;
6503 char *n, *v;
6504 u_int ll;
6505
6506 if (j != arglen - 1) {
6507 _rtld_error("Invalid options: %s", arg);
6508 rtld_die();
6509 }
6510 i++;
6511 n = argv[i];
6512 v = strchr(n, '=');
6513 if (v == NULL) {
6514 _rtld_error("No '=' in -o parameter");
6515 rtld_die();
6516 }
6517 for (ll = 0; ll < nitems(ld_env_vars); ll++) {
6518 l = &ld_env_vars[ll];
6519 if (v - n == (ptrdiff_t)strlen(l->n) &&
6520 strncmp(n, l->n, v - n) == 0) {
6521 l->val = v + 1;
6522 break;
6523 }
6524 }
6525 if (ll == nitems(ld_env_vars)) {
6526 _rtld_error("Unknown LD_ option %s", n);
6527 rtld_die();
6528 }
6529 } else if (opt == 'p') {
6530 *use_pathp = true;
6531 } else if (opt == 'u') {
6532 u_int ll;
6533
6534 for (ll = 0; ll < nitems(ld_env_vars); ll++)
6535 ld_env_vars[ll].val = NULL;
6536 } else if (opt == 'v') {
6537 machine[0] = '\0';
6538 mib[0] = CTL_HW;
6539 mib[1] = HW_MACHINE;
6540 sz = sizeof(machine);
6541 sysctl(mib, nitems(mib), machine, &sz, NULL, 0);
6542 ld_elf_hints_path = ld_get_env_var(
6543 LD_ELF_HINTS_PATH);
6544 set_ld_elf_hints_path();
6545 rtld_printf(
6546 "FreeBSD ld-elf.so.1 %s\n"
6547 "FreeBSD_version %d\n"
6548 "Default lib path %s\n"
6549 "Hints lib path %s\n"
6550 "Env prefix %s\n"
6551 "Default hint file %s\n"
6552 "Hint file %s\n"
6553 "libmap file %s\n"
6554 "Optional static TLS size %zd bytes\n",
6555 machine, __FreeBSD_version,
6556 ld_standard_library_path, gethints(false),
6557 ld_env_prefix, ld_elf_hints_default,
6558 ld_elf_hints_path, ld_path_libmap_conf,
6559 ld_static_tls_extra);
6560 _exit(0);
6561 } else {
6562 _rtld_error("Invalid argument: '%s'", arg);
6563 print_usage(argv[0]);
6564 rtld_die();
6565 }
6566 }
6567 }
6568
6569 if (!seen_b)
6570 *argv0 = argv[i];
6571 return (i);
6572 }
6573
6574 /*
6575 * Parse a file descriptor number without pulling in more of libc (e.g. atoi).
6576 */
6577 static int
parse_integer(const char * str)6578 parse_integer(const char *str)
6579 {
6580 int radix;
6581 const char *orig;
6582 int n, val;
6583 char c;
6584
6585 if (str[0] == '0') {
6586 if (str[1] == 'x') {
6587 str += 2;
6588 radix = 16;
6589 } else if (str[1] == 'b') {
6590 str += 2;
6591 radix = 2;
6592 } else {
6593 str += 1;
6594 radix = 8;
6595 }
6596 } else {
6597 radix = 10;
6598 }
6599 orig = str;
6600 n = 0;
6601 for (c = *str; c != '\0'; c = *++str) {
6602 if (c >= '0' && c <= '9')
6603 val = c - '0';
6604 else if (c >= 'a' && c <= 'f')
6605 val = c - 'a' + 10;
6606 else if (c >= 'A' && c <= 'F')
6607 val = c - 'A' + 10;
6608 else
6609 return (-1);
6610 if (val >= radix)
6611 return (-1);
6612
6613 if (n > INT_MAX / radix)
6614 return (-1);
6615 n *= radix;
6616 if (n > INT_MAX - val)
6617 return (-1);
6618 n += val;
6619 }
6620
6621 /*
6622 * Make sure we actually parsed something.
6623 * Allow for lone '0'.
6624 */
6625 if (str == orig && radix != 8)
6626 return (-1);
6627 return (n);
6628 }
6629
6630 static void
print_usage(const char * argv0)6631 print_usage(const char *argv0)
6632 {
6633 rtld_printf(
6634 "Usage: %s [-h] [-b <exe>] [-d] [-f <FD>] [-p] [--] <binary> [<args>]\n"
6635 "\n"
6636 "Options:\n"
6637 " -h Display this help message\n"
6638 " -b <exe> Execute <exe> instead of <binary>, arg0 is <binary>\n"
6639 " -d Ignore lack of exec permissions for the binary\n"
6640 " -f <FD> Execute <FD> instead of searching for <binary>\n"
6641 " -o <OPT>=<VAL> Set LD_<OPT> to <VAL>, without polluting env\n"
6642 " -p Search in PATH for named binary\n"
6643 " -u Ignore LD_ environment variables\n"
6644 " -v Display identification information\n"
6645 " -- End of RTLD options\n"
6646 " <binary> Name of process to execute\n"
6647 " <args> Arguments to the executed process\n",
6648 argv0);
6649 }
6650
6651 #define AUXFMT(at, xfmt) [at] = { .name = #at, .fmt = xfmt }
6652 static const struct auxfmt {
6653 const char *name;
6654 const char *fmt;
6655 } auxfmts[] = {
6656 AUXFMT(AT_NULL, NULL),
6657 AUXFMT(AT_IGNORE, NULL),
6658 AUXFMT(AT_EXECFD, "%ld"),
6659 AUXFMT(AT_PHDR, "%p"),
6660 AUXFMT(AT_PHENT, "%lu"),
6661 AUXFMT(AT_PHNUM, "%lu"),
6662 AUXFMT(AT_PAGESZ, "%lu"),
6663 AUXFMT(AT_BASE, "%#lx"),
6664 AUXFMT(AT_FLAGS, "%#lx"),
6665 AUXFMT(AT_ENTRY, "%p"),
6666 AUXFMT(AT_NOTELF, NULL),
6667 AUXFMT(AT_UID, "%ld"),
6668 AUXFMT(AT_EUID, "%ld"),
6669 AUXFMT(AT_GID, "%ld"),
6670 AUXFMT(AT_EGID, "%ld"),
6671 AUXFMT(AT_EXECPATH, "%s"),
6672 AUXFMT(AT_CANARY, "%p"),
6673 AUXFMT(AT_CANARYLEN, "%lu"),
6674 AUXFMT(AT_OSRELDATE, "%lu"),
6675 AUXFMT(AT_NCPUS, "%lu"),
6676 AUXFMT(AT_PAGESIZES, "%p"),
6677 AUXFMT(AT_PAGESIZESLEN, "%lu"),
6678 AUXFMT(AT_TIMEKEEP, "%p"),
6679 AUXFMT(AT_STACKPROT, "%#lx"),
6680 AUXFMT(AT_EHDRFLAGS, "%#lx"),
6681 AUXFMT(AT_HWCAP, "%#lx"),
6682 AUXFMT(AT_HWCAP2, "%#lx"),
6683 AUXFMT(AT_BSDFLAGS, "%#lx"),
6684 AUXFMT(AT_ARGC, "%lu"),
6685 AUXFMT(AT_ARGV, "%p"),
6686 AUXFMT(AT_ENVC, "%p"),
6687 AUXFMT(AT_ENVV, "%p"),
6688 AUXFMT(AT_PS_STRINGS, "%p"),
6689 AUXFMT(AT_FXRNG, "%p"),
6690 AUXFMT(AT_KPRELOAD, "%p"),
6691 AUXFMT(AT_USRSTACKBASE, "%#lx"),
6692 AUXFMT(AT_USRSTACKLIM, "%#lx"),
6693 /* AT_CHERI_STATS */
6694 AUXFMT(AT_HWCAP3, "%#lx"),
6695 AUXFMT(AT_HWCAP4, "%#lx"),
6696
6697 };
6698
6699 static bool
is_ptr_fmt(const char * fmt)6700 is_ptr_fmt(const char *fmt)
6701 {
6702 char last;
6703
6704 last = fmt[strlen(fmt) - 1];
6705 return (last == 'p' || last == 's');
6706 }
6707
6708 static void
dump_auxv(Elf_Auxinfo ** aux_info)6709 dump_auxv(Elf_Auxinfo **aux_info)
6710 {
6711 Elf_Auxinfo *auxp;
6712 const struct auxfmt *fmt;
6713 int i;
6714
6715 for (i = 0; i < AT_COUNT; i++) {
6716 auxp = aux_info[i];
6717 if (auxp == NULL)
6718 continue;
6719 fmt = &auxfmts[i];
6720 if (fmt->fmt == NULL)
6721 continue;
6722 rtld_fdprintf(STDOUT_FILENO, "%s:\t", fmt->name);
6723 if (is_ptr_fmt(fmt->fmt)) {
6724 rtld_fdprintfx(STDOUT_FILENO, fmt->fmt,
6725 auxp->a_un.a_ptr);
6726 } else {
6727 rtld_fdprintfx(STDOUT_FILENO, fmt->fmt,
6728 auxp->a_un.a_val);
6729 }
6730 rtld_fdprintf(STDOUT_FILENO, "\n");
6731 }
6732 }
6733
6734 const char *
rtld_get_var(const char * name)6735 rtld_get_var(const char *name)
6736 {
6737 const struct ld_env_var_desc *lvd;
6738 u_int i;
6739
6740 for (i = 0; i < nitems(ld_env_vars); i++) {
6741 lvd = &ld_env_vars[i];
6742 if (strcmp(lvd->n, name) == 0)
6743 return (lvd->val);
6744 }
6745 return (NULL);
6746 }
6747
6748 static void
rtld_recalc_dangerous_ld_env(void)6749 rtld_recalc_dangerous_ld_env(void)
6750 {
6751 /*
6752 * Never reset dangerous_ld_env back to false if rtld was ever
6753 * contaminated with it set to true.
6754 */
6755 dangerous_ld_env |= libmap_disable || libmap_override != NULL ||
6756 ld_library_path != NULL || ld_preload != NULL ||
6757 ld_elf_hints_path != NULL || ld_loadfltr || !ld_dynamic_weak ||
6758 ld_get_env_var(LD_STATIC_TLS_EXTRA) != NULL;
6759 }
6760
6761 static void
rtld_recalc_debug(const char * ld_debug)6762 rtld_recalc_debug(const char *ld_debug)
6763 {
6764 if (ld_debug != NULL && *ld_debug != '\0')
6765 debug = 1;
6766 }
6767
6768 static void
rtld_set_var_debug(struct ld_env_var_desc * lvd)6769 rtld_set_var_debug(struct ld_env_var_desc *lvd)
6770 {
6771 rtld_recalc_debug(lvd->val);
6772 }
6773
6774 static void
rtld_set_var_library_path(struct ld_env_var_desc * lvd)6775 rtld_set_var_library_path(struct ld_env_var_desc *lvd)
6776 {
6777 ld_library_path = lvd->val;
6778 }
6779
6780 static void
rtld_set_var_library_path_fds(struct ld_env_var_desc * lvd)6781 rtld_set_var_library_path_fds(struct ld_env_var_desc *lvd)
6782 {
6783 ld_library_dirs = lvd->val;
6784 }
6785
6786 static void
rtld_recalc_path_rpath(const char * library_path_rpath)6787 rtld_recalc_path_rpath(const char *library_path_rpath)
6788 {
6789 if (library_path_rpath != NULL) {
6790 if (library_path_rpath[0] == 'y' ||
6791 library_path_rpath[0] == 'Y' ||
6792 library_path_rpath[0] == '1')
6793 ld_library_path_rpath = true;
6794 else
6795 ld_library_path_rpath = false;
6796 } else {
6797 ld_library_path_rpath = false;
6798 }
6799 }
6800
6801 static void
rtld_set_var_library_path_rpath(struct ld_env_var_desc * lvd)6802 rtld_set_var_library_path_rpath(struct ld_env_var_desc *lvd)
6803 {
6804 rtld_recalc_path_rpath(lvd->val);
6805 }
6806
6807 static void
rtld_recalc_bind_not(const char * bind_not_val)6808 rtld_recalc_bind_not(const char *bind_not_val)
6809 {
6810 if (ld_bind_now == NULL)
6811 ld_bind_not = bind_not_val != NULL;
6812 }
6813
6814 static void
rtld_set_var_bind_now(struct ld_env_var_desc * lvd)6815 rtld_set_var_bind_now(struct ld_env_var_desc *lvd)
6816 {
6817 ld_bind_now = lvd->val;
6818 rtld_recalc_bind_not(ld_get_env_var(LD_BIND_NOT));
6819 }
6820
6821 static void
rtld_set_var_bind_not(struct ld_env_var_desc * lvd)6822 rtld_set_var_bind_not(struct ld_env_var_desc *lvd)
6823 {
6824 rtld_recalc_bind_not(lvd->val);
6825 }
6826
6827 static void
rtld_set_var_dynamic_weak(struct ld_env_var_desc * lvd)6828 rtld_set_var_dynamic_weak(struct ld_env_var_desc *lvd)
6829 {
6830 ld_dynamic_weak = lvd->val == NULL;
6831 }
6832
6833 static void
rtld_set_var_loadfltr(struct ld_env_var_desc * lvd)6834 rtld_set_var_loadfltr(struct ld_env_var_desc *lvd)
6835 {
6836 ld_loadfltr = lvd->val != NULL;
6837 }
6838
6839 static void
rtld_set_var_libmap_disable(struct ld_env_var_desc * lvd)6840 rtld_set_var_libmap_disable(struct ld_env_var_desc *lvd)
6841 {
6842 libmap_disable = lvd->val != NULL;
6843 }
6844
6845 int
rtld_set_var(const char * name,const char * val)6846 rtld_set_var(const char *name, const char *val)
6847 {
6848 RtldLockState lockstate;
6849 struct ld_env_var_desc *lvd;
6850 u_int i;
6851 int error;
6852
6853 error = ENOENT;
6854 wlock_acquire(rtld_bind_lock, &lockstate);
6855 for (i = 0; i < nitems(ld_env_vars); i++) {
6856 lvd = &ld_env_vars[i];
6857 if (strcmp(lvd->n, name) != 0)
6858 continue;
6859 if (!lvd->can_update || (lvd->unsecure && !trust)) {
6860 error = EPERM;
6861 break;
6862 }
6863 if (lvd->owned)
6864 free(__DECONST(char *, lvd->val));
6865 if (val != NULL)
6866 lvd->val = xstrdup(val);
6867 else
6868 lvd->val = NULL;
6869 lvd->owned = true;
6870 if (lvd->on_update != NULL)
6871 lvd->on_update(lvd);
6872 error = 0;
6873 break;
6874 }
6875 if (error == 0)
6876 rtld_recalc_dangerous_ld_env();
6877 lock_release(rtld_bind_lock, &lockstate);
6878 return (error);
6879 }
6880
6881 /*
6882 * Overrides for libc_pic-provided functions.
6883 */
6884
6885 int
__getosreldate(void)6886 __getosreldate(void)
6887 {
6888 size_t len;
6889 int oid[2];
6890 int error, osrel;
6891
6892 if (osreldate != 0)
6893 return (osreldate);
6894
6895 oid[0] = CTL_KERN;
6896 oid[1] = KERN_OSRELDATE;
6897 osrel = 0;
6898 len = sizeof(osrel);
6899 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
6900 if (error == 0 && osrel > 0 && len == sizeof(osrel))
6901 osreldate = osrel;
6902 return (osreldate);
6903 }
6904 const char *
rtld_strerror(int errnum)6905 rtld_strerror(int errnum)
6906 {
6907 if (errnum < 0 || errnum >= sys_nerr)
6908 return ("Unknown error");
6909 return (sys_errlist[errnum]);
6910 }
6911
6912 char *
getenv(const char * name)6913 getenv(const char *name)
6914 {
6915 return (__DECONST(char *, rtld_get_env_val(environ, name,
6916 strlen(name))));
6917 }
6918
6919 extern int _rtld_version__FreeBSD_version __exported;
6920 int _rtld_version__FreeBSD_version = __FreeBSD_version;
6921
6922 extern char _rtld_version_laddr_offset __exported;
6923 char _rtld_version_laddr_offset;
6924
6925 extern char _rtld_version_dlpi_tls_data __exported;
6926 char _rtld_version_dlpi_tls_data;
6927