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