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