1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 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/cdefs.h> 42 __FBSDID("$FreeBSD$"); 43 44 #include <sys/param.h> 45 #include <sys/mount.h> 46 #include <sys/mman.h> 47 #include <sys/stat.h> 48 #include <sys/sysctl.h> 49 #include <sys/uio.h> 50 #include <sys/utsname.h> 51 #include <sys/ktrace.h> 52 53 #include <dlfcn.h> 54 #include <err.h> 55 #include <errno.h> 56 #include <fcntl.h> 57 #include <stdarg.h> 58 #include <stdio.h> 59 #include <stdlib.h> 60 #include <string.h> 61 #include <unistd.h> 62 63 #include "debug.h" 64 #include "rtld.h" 65 #include "libmap.h" 66 #include "rtld_paths.h" 67 #include "rtld_tls.h" 68 #include "rtld_printf.h" 69 #include "rtld_malloc.h" 70 #include "rtld_utrace.h" 71 #include "notes.h" 72 #include "rtld_libc.h" 73 74 /* Types. */ 75 typedef void (*func_ptr_type)(void); 76 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 77 78 79 /* Variables that cannot be static: */ 80 extern struct r_debug r_debug; /* For GDB */ 81 extern int _thread_autoinit_dummy_decl; 82 extern void (*__cleanup)(void); 83 84 struct dlerror_save { 85 int seen; 86 char *msg; 87 }; 88 89 /* 90 * Function declarations. 91 */ 92 static const char *basename(const char *); 93 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 94 const Elf_Dyn **, const Elf_Dyn **); 95 static bool digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 96 const Elf_Dyn *); 97 static bool digest_dynamic(Obj_Entry *, int); 98 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 99 static void distribute_static_tls(Objlist *, RtldLockState *); 100 static Obj_Entry *dlcheck(void *); 101 static int dlclose_locked(void *, RtldLockState *); 102 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 103 int lo_flags, int mode, RtldLockState *lockstate); 104 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 105 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 106 static bool donelist_check(DoneList *, const Obj_Entry *); 107 static void dump_auxv(Elf_Auxinfo **aux_info); 108 static void errmsg_restore(struct dlerror_save *); 109 static struct dlerror_save *errmsg_save(void); 110 static void *fill_search_info(const char *, size_t, void *); 111 static char *find_library(const char *, const Obj_Entry *, int *); 112 static const char *gethints(bool); 113 static void hold_object(Obj_Entry *); 114 static void unhold_object(Obj_Entry *); 115 static void init_dag(Obj_Entry *); 116 static void init_marker(Obj_Entry *); 117 static void init_pagesizes(Elf_Auxinfo **aux_info); 118 static void init_rtld(caddr_t, Elf_Auxinfo **); 119 static void initlist_add_neededs(Needed_Entry *, Objlist *); 120 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *); 121 static int initlist_objects_ifunc(Objlist *, bool, int, RtldLockState *); 122 static void linkmap_add(Obj_Entry *); 123 static void linkmap_delete(Obj_Entry *); 124 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 125 static void unload_filtees(Obj_Entry *, RtldLockState *); 126 static int load_needed_objects(Obj_Entry *, int); 127 static int load_preload_objects(const char *, bool); 128 static int load_kpreload(const void *addr); 129 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 130 static void map_stacks_exec(RtldLockState *); 131 static int obj_disable_relro(Obj_Entry *); 132 static int obj_enforce_relro(Obj_Entry *); 133 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 134 static void objlist_call_init(Objlist *, RtldLockState *); 135 static void objlist_clear(Objlist *); 136 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 137 static void objlist_init(Objlist *); 138 static void objlist_push_head(Objlist *, Obj_Entry *); 139 static void objlist_push_tail(Objlist *, Obj_Entry *); 140 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 141 static void objlist_remove(Objlist *, Obj_Entry *); 142 static int open_binary_fd(const char *argv0, bool search_in_path, 143 const char **binpath_res); 144 static int parse_args(char* argv[], int argc, bool *use_pathp, int *fdp, 145 const char **argv0, bool *dir_ignore); 146 static int parse_integer(const char *); 147 static void *path_enumerate(const char *, path_enum_proc, const char *, void *); 148 static void print_usage(const char *argv0); 149 static void release_object(Obj_Entry *); 150 static int relocate_object_dag(Obj_Entry *root, bool bind_now, 151 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 152 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 153 int flags, RtldLockState *lockstate); 154 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 155 RtldLockState *); 156 static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *); 157 static int rtld_dirname(const char *, char *); 158 static int rtld_dirname_abs(const char *, char *); 159 static void *rtld_dlopen(const char *name, int fd, int mode); 160 static void rtld_exit(void); 161 static void rtld_nop_exit(void); 162 static char *search_library_path(const char *, const char *, const char *, 163 int *); 164 static char *search_library_pathfds(const char *, const char *, int *); 165 static const void **get_program_var_addr(const char *, RtldLockState *); 166 static void set_program_var(const char *, const void *); 167 static int symlook_default(SymLook *, const Obj_Entry *refobj); 168 static int symlook_global(SymLook *, DoneList *); 169 static void symlook_init_from_req(SymLook *, const SymLook *); 170 static int symlook_list(SymLook *, const Objlist *, DoneList *); 171 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 172 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 173 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 174 static void *tls_get_addr_slow(Elf_Addr **, int, size_t, bool) __noinline; 175 static void trace_loaded_objects(Obj_Entry *, bool); 176 static void unlink_object(Obj_Entry *); 177 static void unload_object(Obj_Entry *, RtldLockState *lockstate); 178 static void unref_dag(Obj_Entry *); 179 static void ref_dag(Obj_Entry *); 180 static char *origin_subst_one(Obj_Entry *, char *, const char *, 181 const char *, bool); 182 static char *origin_subst(Obj_Entry *, const char *); 183 static bool obj_resolve_origin(Obj_Entry *obj); 184 static void preinit_main(void); 185 static int rtld_verify_versions(const Objlist *); 186 static int rtld_verify_object_versions(Obj_Entry *); 187 static void object_add_name(Obj_Entry *, const char *); 188 static int object_match_name(const Obj_Entry *, const char *); 189 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 190 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 191 struct dl_phdr_info *phdr_info); 192 static uint32_t gnu_hash(const char *); 193 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 194 const unsigned long); 195 196 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 197 void _r_debug_postinit(struct link_map *) __noinline __exported; 198 199 int __sys_openat(int, const char *, int, ...); 200 201 /* 202 * Data declarations. 203 */ 204 struct r_debug r_debug __exported; /* for GDB; */ 205 static bool libmap_disable; /* Disable libmap */ 206 static bool ld_loadfltr; /* Immediate filters processing */ 207 static const char *libmap_override;/* Maps to use in addition to libmap.conf */ 208 static bool trust; /* False for setuid and setgid programs */ 209 static bool dangerous_ld_env; /* True if environment variables have been 210 used to affect the libraries loaded */ 211 bool ld_bind_not; /* Disable PLT update */ 212 static const char *ld_bind_now; /* Environment variable for immediate binding */ 213 static const char *ld_debug; /* Environment variable for debugging */ 214 static bool ld_dynamic_weak = true; /* True if non-weak definition overrides 215 weak definition */ 216 static const char *ld_library_path;/* Environment variable for search path */ 217 static const char *ld_library_dirs;/* Environment variable for library descriptors */ 218 static const char *ld_preload; /* Environment variable for libraries to 219 load first */ 220 static const char *ld_preload_fds;/* Environment variable for libraries represented by 221 descriptors */ 222 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 223 static const char *ld_tracing; /* Called from ldd to print libs */ 224 static const char *ld_utrace; /* Use utrace() to log events. */ 225 static struct obj_entry_q obj_list; /* Queue of all loaded objects */ 226 static Obj_Entry *obj_main; /* The main program shared object */ 227 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 228 static unsigned int obj_count; /* Number of objects in obj_list */ 229 static unsigned int obj_loads; /* Number of loads of objects (gen count) */ 230 231 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 232 STAILQ_HEAD_INITIALIZER(list_global); 233 static Objlist list_main = /* Objects loaded at program startup */ 234 STAILQ_HEAD_INITIALIZER(list_main); 235 static Objlist list_fini = /* Objects needing fini() calls */ 236 STAILQ_HEAD_INITIALIZER(list_fini); 237 238 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 239 240 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 241 242 extern Elf_Dyn _DYNAMIC; 243 #pragma weak _DYNAMIC 244 245 int dlclose(void *) __exported; 246 char *dlerror(void) __exported; 247 void *dlopen(const char *, int) __exported; 248 void *fdlopen(int, int) __exported; 249 void *dlsym(void *, const char *) __exported; 250 dlfunc_t dlfunc(void *, const char *) __exported; 251 void *dlvsym(void *, const char *, const char *) __exported; 252 int dladdr(const void *, Dl_info *) __exported; 253 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 254 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 255 int dlinfo(void *, int , void *) __exported; 256 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 257 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 258 int _rtld_get_stack_prot(void) __exported; 259 int _rtld_is_dlopened(void *) __exported; 260 void _rtld_error(const char *, ...) __exported; 261 262 /* Only here to fix -Wmissing-prototypes warnings */ 263 int __getosreldate(void); 264 func_ptr_type _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp); 265 Elf_Addr _rtld_bind(Obj_Entry *obj, Elf_Size reloff); 266 267 268 int npagesizes; 269 static int osreldate; 270 size_t *pagesizes; 271 272 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 273 static int max_stack_flags; 274 275 /* 276 * Global declarations normally provided by crt1. The dynamic linker is 277 * not built with crt1, so we have to provide them ourselves. 278 */ 279 char *__progname; 280 char **environ; 281 282 /* 283 * Used to pass argc, argv to init functions. 284 */ 285 int main_argc; 286 char **main_argv; 287 288 /* 289 * Globals to control TLS allocation. 290 */ 291 size_t tls_last_offset; /* Static TLS offset of last module */ 292 size_t tls_last_size; /* Static TLS size of last module */ 293 size_t tls_static_space; /* Static TLS space allocated */ 294 static size_t tls_static_max_align; 295 Elf_Addr tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 296 int tls_max_index = 1; /* Largest module index allocated */ 297 298 static bool ld_library_path_rpath = false; 299 bool ld_fast_sigblock = false; 300 301 /* 302 * Globals for path names, and such 303 */ 304 const char *ld_elf_hints_default = _PATH_ELF_HINTS; 305 const char *ld_path_libmap_conf = _PATH_LIBMAP_CONF; 306 const char *ld_path_rtld = _PATH_RTLD; 307 const char *ld_standard_library_path = STANDARD_LIBRARY_PATH; 308 const char *ld_env_prefix = LD_; 309 310 static void (*rtld_exit_ptr)(void); 311 312 /* 313 * Fill in a DoneList with an allocation large enough to hold all of 314 * the currently-loaded objects. Keep this as a macro since it calls 315 * alloca and we want that to occur within the scope of the caller. 316 */ 317 #define donelist_init(dlp) \ 318 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 319 assert((dlp)->objs != NULL), \ 320 (dlp)->num_alloc = obj_count, \ 321 (dlp)->num_used = 0) 322 323 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 324 if (ld_utrace != NULL) \ 325 ld_utrace_log(e, h, mb, ms, r, n); \ 326 } while (0) 327 328 static void 329 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 330 int refcnt, const char *name) 331 { 332 struct utrace_rtld ut; 333 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG; 334 335 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig)); 336 ut.event = event; 337 ut.handle = handle; 338 ut.mapbase = mapbase; 339 ut.mapsize = mapsize; 340 ut.refcnt = refcnt; 341 bzero(ut.name, sizeof(ut.name)); 342 if (name) 343 strlcpy(ut.name, name, sizeof(ut.name)); 344 utrace(&ut, sizeof(ut)); 345 } 346 347 enum { 348 LD_BIND_NOW = 0, 349 LD_PRELOAD, 350 LD_LIBMAP, 351 LD_LIBRARY_PATH, 352 LD_LIBRARY_PATH_FDS, 353 LD_LIBMAP_DISABLE, 354 LD_BIND_NOT, 355 LD_DEBUG, 356 LD_ELF_HINTS_PATH, 357 LD_LOADFLTR, 358 LD_LIBRARY_PATH_RPATH, 359 LD_PRELOAD_FDS, 360 LD_DYNAMIC_WEAK, 361 LD_TRACE_LOADED_OBJECTS, 362 LD_UTRACE, 363 LD_DUMP_REL_PRE, 364 LD_DUMP_REL_POST, 365 LD_TRACE_LOADED_OBJECTS_PROGNAME, 366 LD_TRACE_LOADED_OBJECTS_FMT1, 367 LD_TRACE_LOADED_OBJECTS_FMT2, 368 LD_TRACE_LOADED_OBJECTS_ALL, 369 LD_SHOW_AUXV, 370 }; 371 372 struct ld_env_var_desc { 373 const char * const n; 374 const char *val; 375 const bool unsecure; 376 }; 377 #define LD_ENV_DESC(var, unsec) \ 378 [LD_##var] = { .n = #var, .unsecure = unsec } 379 380 static struct ld_env_var_desc ld_env_vars[] = { 381 LD_ENV_DESC(BIND_NOW, false), 382 LD_ENV_DESC(PRELOAD, true), 383 LD_ENV_DESC(LIBMAP, true), 384 LD_ENV_DESC(LIBRARY_PATH, true), 385 LD_ENV_DESC(LIBRARY_PATH_FDS, true), 386 LD_ENV_DESC(LIBMAP_DISABLE, true), 387 LD_ENV_DESC(BIND_NOT, true), 388 LD_ENV_DESC(DEBUG, true), 389 LD_ENV_DESC(ELF_HINTS_PATH, true), 390 LD_ENV_DESC(LOADFLTR, true), 391 LD_ENV_DESC(LIBRARY_PATH_RPATH, true), 392 LD_ENV_DESC(PRELOAD_FDS, true), 393 LD_ENV_DESC(DYNAMIC_WEAK, true), 394 LD_ENV_DESC(TRACE_LOADED_OBJECTS, false), 395 LD_ENV_DESC(UTRACE, false), 396 LD_ENV_DESC(DUMP_REL_PRE, false), 397 LD_ENV_DESC(DUMP_REL_POST, false), 398 LD_ENV_DESC(TRACE_LOADED_OBJECTS_PROGNAME, false), 399 LD_ENV_DESC(TRACE_LOADED_OBJECTS_FMT1, false), 400 LD_ENV_DESC(TRACE_LOADED_OBJECTS_FMT2, false), 401 LD_ENV_DESC(TRACE_LOADED_OBJECTS_ALL, false), 402 LD_ENV_DESC(SHOW_AUXV, false), 403 }; 404 405 static const char * 406 ld_get_env_var(int idx) 407 { 408 return (ld_env_vars[idx].val); 409 } 410 411 static const char * 412 rtld_get_env_val(char **env, const char *name, size_t name_len) 413 { 414 char **m, *n, *v; 415 416 for (m = env; *m != NULL; m++) { 417 n = *m; 418 v = strchr(n, '='); 419 if (v == NULL) { 420 /* corrupt environment? */ 421 continue; 422 } 423 if (v - n == (ptrdiff_t)name_len && 424 strncmp(name, n, name_len) == 0) 425 return (v + 1); 426 } 427 return (NULL); 428 } 429 430 static void 431 rtld_init_env_vars_for_prefix(char **env, const char *env_prefix) 432 { 433 struct ld_env_var_desc *lvd; 434 size_t prefix_len, nlen; 435 char **m, *n, *v; 436 int i; 437 438 prefix_len = strlen(env_prefix); 439 for (m = env; *m != NULL; m++) { 440 n = *m; 441 if (strncmp(env_prefix, n, prefix_len) != 0) { 442 /* Not a rtld environment variable. */ 443 continue; 444 } 445 n += prefix_len; 446 v = strchr(n, '='); 447 if (v == NULL) { 448 /* corrupt environment? */ 449 continue; 450 } 451 for (i = 0; i < (int)nitems(ld_env_vars); i++) { 452 lvd = &ld_env_vars[i]; 453 if (lvd->val != NULL) { 454 /* Saw higher-priority variable name already. */ 455 continue; 456 } 457 nlen = strlen(lvd->n); 458 if (v - n == (ptrdiff_t)nlen && 459 strncmp(lvd->n, n, nlen) == 0) { 460 lvd->val = v + 1; 461 break; 462 } 463 } 464 } 465 } 466 467 static void 468 rtld_init_env_vars(char **env) 469 { 470 rtld_init_env_vars_for_prefix(env, ld_env_prefix); 471 } 472 473 static void 474 set_ld_elf_hints_path(void) 475 { 476 if (ld_elf_hints_path == NULL || strlen(ld_elf_hints_path) == 0) 477 ld_elf_hints_path = ld_elf_hints_default; 478 } 479 480 /* 481 * Main entry point for dynamic linking. The first argument is the 482 * stack pointer. The stack is expected to be laid out as described 483 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 484 * Specifically, the stack pointer points to a word containing 485 * ARGC. Following that in the stack is a null-terminated sequence 486 * of pointers to argument strings. Then comes a null-terminated 487 * sequence of pointers to environment strings. Finally, there is a 488 * sequence of "auxiliary vector" entries. 489 * 490 * The second argument points to a place to store the dynamic linker's 491 * exit procedure pointer and the third to a place to store the main 492 * program's object. 493 * 494 * The return value is the main program's entry point. 495 */ 496 func_ptr_type 497 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 498 { 499 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT]; 500 Objlist_Entry *entry; 501 Obj_Entry *last_interposer, *obj, *preload_tail; 502 const Elf_Phdr *phdr; 503 Objlist initlist; 504 RtldLockState lockstate; 505 struct stat st; 506 Elf_Addr *argcp; 507 char **argv, **env, **envp, *kexecpath; 508 const char *argv0, *binpath, *library_path_rpath; 509 struct ld_env_var_desc *lvd; 510 caddr_t imgentry; 511 char buf[MAXPATHLEN]; 512 int argc, fd, i, mib[4], old_osrel, osrel, phnum, rtld_argc; 513 size_t sz; 514 #ifdef __powerpc__ 515 int old_auxv_format = 1; 516 #endif 517 bool dir_enable, dir_ignore, direct_exec, explicit_fd, search_in_path; 518 519 /* 520 * On entry, the dynamic linker itself has not been relocated yet. 521 * Be very careful not to reference any global data until after 522 * init_rtld has returned. It is OK to reference file-scope statics 523 * and string constants, and to call static and global functions. 524 */ 525 526 /* Find the auxiliary vector on the stack. */ 527 argcp = sp; 528 argc = *sp++; 529 argv = (char **) sp; 530 sp += argc + 1; /* Skip over arguments and NULL terminator */ 531 env = (char **) sp; 532 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 533 ; 534 aux = (Elf_Auxinfo *) sp; 535 536 /* Digest the auxiliary vector. */ 537 for (i = 0; i < AT_COUNT; i++) 538 aux_info[i] = NULL; 539 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 540 if (auxp->a_type < AT_COUNT) 541 aux_info[auxp->a_type] = auxp; 542 #ifdef __powerpc__ 543 if (auxp->a_type == 23) /* AT_STACKPROT */ 544 old_auxv_format = 0; 545 #endif 546 } 547 548 #ifdef __powerpc__ 549 if (old_auxv_format) { 550 /* Remap from old-style auxv numbers. */ 551 aux_info[23] = aux_info[21]; /* AT_STACKPROT */ 552 aux_info[21] = aux_info[19]; /* AT_PAGESIZESLEN */ 553 aux_info[19] = aux_info[17]; /* AT_NCPUS */ 554 aux_info[17] = aux_info[15]; /* AT_CANARYLEN */ 555 aux_info[15] = aux_info[13]; /* AT_EXECPATH */ 556 aux_info[13] = NULL; /* AT_GID */ 557 558 aux_info[20] = aux_info[18]; /* AT_PAGESIZES */ 559 aux_info[18] = aux_info[16]; /* AT_OSRELDATE */ 560 aux_info[16] = aux_info[14]; /* AT_CANARY */ 561 aux_info[14] = NULL; /* AT_EGID */ 562 } 563 #endif 564 565 /* Initialize and relocate ourselves. */ 566 assert(aux_info[AT_BASE] != NULL); 567 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 568 569 dlerror_dflt_init(); 570 571 __progname = obj_rtld.path; 572 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 573 environ = env; 574 main_argc = argc; 575 main_argv = argv; 576 577 if (aux_info[AT_BSDFLAGS] != NULL && 578 (aux_info[AT_BSDFLAGS]->a_un.a_val & ELF_BSDF_SIGFASTBLK) != 0) 579 ld_fast_sigblock = true; 580 581 trust = !issetugid(); 582 direct_exec = false; 583 584 md_abi_variant_hook(aux_info); 585 rtld_init_env_vars(env); 586 587 fd = -1; 588 if (aux_info[AT_EXECFD] != NULL) { 589 fd = aux_info[AT_EXECFD]->a_un.a_val; 590 } else { 591 assert(aux_info[AT_PHDR] != NULL); 592 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr; 593 if (phdr == obj_rtld.phdr) { 594 if (!trust) { 595 _rtld_error("Tainted process refusing to run binary %s", 596 argv0); 597 rtld_die(); 598 } 599 direct_exec = true; 600 601 dbg("opening main program in direct exec mode"); 602 if (argc >= 2) { 603 rtld_argc = parse_args(argv, argc, &search_in_path, &fd, 604 &argv0, &dir_ignore); 605 explicit_fd = (fd != -1); 606 binpath = NULL; 607 if (!explicit_fd) 608 fd = open_binary_fd(argv0, search_in_path, &binpath); 609 if (fstat(fd, &st) == -1) { 610 _rtld_error("Failed to fstat FD %d (%s): %s", fd, 611 explicit_fd ? "user-provided descriptor" : argv0, 612 rtld_strerror(errno)); 613 rtld_die(); 614 } 615 616 /* 617 * Rough emulation of the permission checks done by 618 * execve(2), only Unix DACs are checked, ACLs are 619 * ignored. Preserve the semantic of disabling owner 620 * to execute if owner x bit is cleared, even if 621 * others x bit is enabled. 622 * mmap(2) does not allow to mmap with PROT_EXEC if 623 * binary' file comes from noexec mount. We cannot 624 * set a text reference on the binary. 625 */ 626 dir_enable = false; 627 if (st.st_uid == geteuid()) { 628 if ((st.st_mode & S_IXUSR) != 0) 629 dir_enable = true; 630 } else if (st.st_gid == getegid()) { 631 if ((st.st_mode & S_IXGRP) != 0) 632 dir_enable = true; 633 } else if ((st.st_mode & S_IXOTH) != 0) { 634 dir_enable = true; 635 } 636 if (!dir_enable && !dir_ignore) { 637 _rtld_error("No execute permission for binary %s", 638 argv0); 639 rtld_die(); 640 } 641 642 /* 643 * For direct exec mode, argv[0] is the interpreter 644 * name, we must remove it and shift arguments left 645 * before invoking binary main. Since stack layout 646 * places environment pointers and aux vectors right 647 * after the terminating NULL, we must shift 648 * environment and aux as well. 649 */ 650 main_argc = argc - rtld_argc; 651 for (i = 0; i <= main_argc; i++) 652 argv[i] = argv[i + rtld_argc]; 653 *argcp -= rtld_argc; 654 environ = env = envp = argv + main_argc + 1; 655 dbg("move env from %p to %p", envp + rtld_argc, envp); 656 do { 657 *envp = *(envp + rtld_argc); 658 } while (*envp++ != NULL); 659 aux = auxp = (Elf_Auxinfo *)envp; 660 auxpf = (Elf_Auxinfo *)(envp + rtld_argc); 661 dbg("move aux from %p to %p", auxpf, aux); 662 /* XXXKIB insert place for AT_EXECPATH if not present */ 663 for (;; auxp++, auxpf++) { 664 *auxp = *auxpf; 665 if (auxp->a_type == AT_NULL) 666 break; 667 } 668 /* Since the auxiliary vector has moved, redigest it. */ 669 for (i = 0; i < AT_COUNT; i++) 670 aux_info[i] = NULL; 671 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 672 if (auxp->a_type < AT_COUNT) 673 aux_info[auxp->a_type] = auxp; 674 } 675 676 /* Point AT_EXECPATH auxv and aux_info to the binary path. */ 677 if (binpath == NULL) { 678 aux_info[AT_EXECPATH] = NULL; 679 } else { 680 if (aux_info[AT_EXECPATH] == NULL) { 681 aux_info[AT_EXECPATH] = xmalloc(sizeof(Elf_Auxinfo)); 682 aux_info[AT_EXECPATH]->a_type = AT_EXECPATH; 683 } 684 aux_info[AT_EXECPATH]->a_un.a_ptr = __DECONST(void *, 685 binpath); 686 } 687 } else { 688 _rtld_error("No binary"); 689 rtld_die(); 690 } 691 } 692 } 693 694 ld_bind_now = ld_get_env_var(LD_BIND_NOW); 695 696 /* 697 * If the process is tainted, then we un-set the dangerous environment 698 * variables. The process will be marked as tainted until setuid(2) 699 * is called. If any child process calls setuid(2) we do not want any 700 * future processes to honor the potentially un-safe variables. 701 */ 702 if (!trust) { 703 for (i = 0; i < (int)nitems(ld_env_vars); i++) { 704 lvd = &ld_env_vars[i]; 705 if (lvd->unsecure) 706 lvd->val = NULL; 707 } 708 } 709 710 ld_debug = ld_get_env_var(LD_DEBUG); 711 if (ld_bind_now == NULL) 712 ld_bind_not = ld_get_env_var(LD_BIND_NOT) != NULL; 713 ld_dynamic_weak = ld_get_env_var(LD_DYNAMIC_WEAK) == NULL; 714 libmap_disable = ld_get_env_var(LD_LIBMAP_DISABLE) != NULL; 715 libmap_override = ld_get_env_var(LD_LIBMAP); 716 ld_library_path = ld_get_env_var(LD_LIBRARY_PATH); 717 ld_library_dirs = ld_get_env_var(LD_LIBRARY_PATH_FDS); 718 ld_preload = ld_get_env_var(LD_PRELOAD); 719 ld_preload_fds = ld_get_env_var(LD_PRELOAD_FDS); 720 ld_elf_hints_path = ld_get_env_var(LD_ELF_HINTS_PATH); 721 ld_loadfltr = ld_get_env_var(LD_LOADFLTR) != NULL; 722 library_path_rpath = ld_get_env_var(LD_LIBRARY_PATH_RPATH); 723 if (library_path_rpath != NULL) { 724 if (library_path_rpath[0] == 'y' || 725 library_path_rpath[0] == 'Y' || 726 library_path_rpath[0] == '1') 727 ld_library_path_rpath = true; 728 else 729 ld_library_path_rpath = false; 730 } 731 dangerous_ld_env = libmap_disable || libmap_override != NULL || 732 ld_library_path != NULL || ld_preload != NULL || 733 ld_elf_hints_path != NULL || ld_loadfltr || !ld_dynamic_weak; 734 ld_tracing = ld_get_env_var(LD_TRACE_LOADED_OBJECTS); 735 ld_utrace = ld_get_env_var(LD_UTRACE); 736 737 set_ld_elf_hints_path(); 738 if (ld_debug != NULL && *ld_debug != '\0') 739 debug = 1; 740 dbg("%s is initialized, base address = %p", __progname, 741 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 742 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 743 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 744 745 dbg("initializing thread locks"); 746 lockdflt_init(); 747 748 /* 749 * Load the main program, or process its program header if it is 750 * already loaded. 751 */ 752 if (fd != -1) { /* Load the main program. */ 753 dbg("loading main program"); 754 obj_main = map_object(fd, argv0, NULL); 755 close(fd); 756 if (obj_main == NULL) 757 rtld_die(); 758 max_stack_flags = obj_main->stack_flags; 759 } else { /* Main program already loaded. */ 760 dbg("processing main program's program header"); 761 assert(aux_info[AT_PHDR] != NULL); 762 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 763 assert(aux_info[AT_PHNUM] != NULL); 764 phnum = aux_info[AT_PHNUM]->a_un.a_val; 765 assert(aux_info[AT_PHENT] != NULL); 766 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 767 assert(aux_info[AT_ENTRY] != NULL); 768 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 769 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL) 770 rtld_die(); 771 } 772 773 if (aux_info[AT_EXECPATH] != NULL && fd == -1) { 774 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 775 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 776 if (kexecpath[0] == '/') 777 obj_main->path = kexecpath; 778 else if (getcwd(buf, sizeof(buf)) == NULL || 779 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 780 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 781 obj_main->path = xstrdup(argv0); 782 else 783 obj_main->path = xstrdup(buf); 784 } else { 785 dbg("No AT_EXECPATH or direct exec"); 786 obj_main->path = xstrdup(argv0); 787 } 788 dbg("obj_main path %s", obj_main->path); 789 obj_main->mainprog = true; 790 791 if (aux_info[AT_STACKPROT] != NULL && 792 aux_info[AT_STACKPROT]->a_un.a_val != 0) 793 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 794 795 #ifndef COMPAT_32BIT 796 /* 797 * Get the actual dynamic linker pathname from the executable if 798 * possible. (It should always be possible.) That ensures that 799 * gdb will find the right dynamic linker even if a non-standard 800 * one is being used. 801 */ 802 if (obj_main->interp != NULL && 803 strcmp(obj_main->interp, obj_rtld.path) != 0) { 804 free(obj_rtld.path); 805 obj_rtld.path = xstrdup(obj_main->interp); 806 __progname = obj_rtld.path; 807 } 808 #endif 809 810 if (!digest_dynamic(obj_main, 0)) 811 rtld_die(); 812 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 813 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 814 obj_main->dynsymcount); 815 816 linkmap_add(obj_main); 817 linkmap_add(&obj_rtld); 818 819 /* Link the main program into the list of objects. */ 820 TAILQ_INSERT_HEAD(&obj_list, obj_main, next); 821 obj_count++; 822 obj_loads++; 823 824 /* Initialize a fake symbol for resolving undefined weak references. */ 825 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 826 sym_zero.st_shndx = SHN_UNDEF; 827 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 828 829 if (!libmap_disable) 830 libmap_disable = (bool)lm_init(libmap_override); 831 832 if (aux_info[AT_KPRELOAD] != NULL && 833 aux_info[AT_KPRELOAD]->a_un.a_ptr != NULL) { 834 dbg("loading kernel vdso"); 835 if (load_kpreload(aux_info[AT_KPRELOAD]->a_un.a_ptr) == -1) 836 rtld_die(); 837 } 838 839 dbg("loading LD_PRELOAD_FDS libraries"); 840 if (load_preload_objects(ld_preload_fds, true) == -1) 841 rtld_die(); 842 843 dbg("loading LD_PRELOAD libraries"); 844 if (load_preload_objects(ld_preload, false) == -1) 845 rtld_die(); 846 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 847 848 dbg("loading needed objects"); 849 if (load_needed_objects(obj_main, ld_tracing != NULL ? RTLD_LO_TRACE : 850 0) == -1) 851 rtld_die(); 852 853 /* Make a list of all objects loaded at startup. */ 854 last_interposer = obj_main; 855 TAILQ_FOREACH(obj, &obj_list, next) { 856 if (obj->marker) 857 continue; 858 if (obj->z_interpose && obj != obj_main) { 859 objlist_put_after(&list_main, last_interposer, obj); 860 last_interposer = obj; 861 } else { 862 objlist_push_tail(&list_main, obj); 863 } 864 obj->refcount++; 865 } 866 867 dbg("checking for required versions"); 868 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 869 rtld_die(); 870 871 if (ld_get_env_var(LD_SHOW_AUXV) != NULL) 872 dump_auxv(aux_info); 873 874 if (ld_tracing) { /* We're done */ 875 trace_loaded_objects(obj_main, true); 876 exit(0); 877 } 878 879 if (ld_get_env_var(LD_DUMP_REL_PRE) != NULL) { 880 dump_relocations(obj_main); 881 exit (0); 882 } 883 884 /* 885 * Processing tls relocations requires having the tls offsets 886 * initialized. Prepare offsets before starting initial 887 * relocation processing. 888 */ 889 dbg("initializing initial thread local storage offsets"); 890 STAILQ_FOREACH(entry, &list_main, link) { 891 /* 892 * Allocate all the initial objects out of the static TLS 893 * block even if they didn't ask for it. 894 */ 895 allocate_tls_offset(entry->obj); 896 } 897 898 if (relocate_objects(obj_main, 899 ld_bind_now != NULL && *ld_bind_now != '\0', 900 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 901 rtld_die(); 902 903 dbg("doing copy relocations"); 904 if (do_copy_relocations(obj_main) == -1) 905 rtld_die(); 906 907 if (ld_get_env_var(LD_DUMP_REL_POST) != NULL) { 908 dump_relocations(obj_main); 909 exit (0); 910 } 911 912 ifunc_init(aux); 913 914 /* 915 * Setup TLS for main thread. This must be done after the 916 * relocations are processed, since tls initialization section 917 * might be the subject for relocations. 918 */ 919 dbg("initializing initial thread local storage"); 920 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list))); 921 922 dbg("initializing key program variables"); 923 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 924 set_program_var("environ", env); 925 set_program_var("__elf_aux_vector", aux); 926 927 /* Make a list of init functions to call. */ 928 objlist_init(&initlist); 929 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)), 930 preload_tail, &initlist); 931 932 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 933 934 map_stacks_exec(NULL); 935 936 if (!obj_main->crt_no_init) { 937 /* 938 * Make sure we don't call the main program's init and fini 939 * functions for binaries linked with old crt1 which calls 940 * _init itself. 941 */ 942 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 943 obj_main->preinit_array = obj_main->init_array = 944 obj_main->fini_array = (Elf_Addr)NULL; 945 } 946 947 if (direct_exec) { 948 /* Set osrel for direct-execed binary */ 949 mib[0] = CTL_KERN; 950 mib[1] = KERN_PROC; 951 mib[2] = KERN_PROC_OSREL; 952 mib[3] = getpid(); 953 osrel = obj_main->osrel; 954 sz = sizeof(old_osrel); 955 dbg("setting osrel to %d", osrel); 956 (void)sysctl(mib, 4, &old_osrel, &sz, &osrel, sizeof(osrel)); 957 } 958 959 wlock_acquire(rtld_bind_lock, &lockstate); 960 961 dbg("resolving ifuncs"); 962 if (initlist_objects_ifunc(&initlist, ld_bind_now != NULL && 963 *ld_bind_now != '\0', SYMLOOK_EARLY, &lockstate) == -1) 964 rtld_die(); 965 966 rtld_exit_ptr = rtld_exit; 967 if (obj_main->crt_no_init) 968 preinit_main(); 969 objlist_call_init(&initlist, &lockstate); 970 _r_debug_postinit(&obj_main->linkmap); 971 objlist_clear(&initlist); 972 dbg("loading filtees"); 973 TAILQ_FOREACH(obj, &obj_list, next) { 974 if (obj->marker) 975 continue; 976 if (ld_loadfltr || obj->z_loadfltr) 977 load_filtees(obj, 0, &lockstate); 978 } 979 980 dbg("enforcing main obj relro"); 981 if (obj_enforce_relro(obj_main) == -1) 982 rtld_die(); 983 984 lock_release(rtld_bind_lock, &lockstate); 985 986 dbg("transferring control to program entry point = %p", obj_main->entry); 987 988 /* Return the exit procedure and the program entry point. */ 989 *exit_proc = rtld_exit_ptr; 990 *objp = obj_main; 991 return ((func_ptr_type)obj_main->entry); 992 } 993 994 void * 995 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 996 { 997 void *ptr; 998 Elf_Addr target; 999 1000 ptr = (void *)make_function_pointer(def, obj); 1001 target = call_ifunc_resolver(ptr); 1002 return ((void *)target); 1003 } 1004 1005 Elf_Addr 1006 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 1007 { 1008 const Elf_Rel *rel; 1009 const Elf_Sym *def; 1010 const Obj_Entry *defobj; 1011 Elf_Addr *where; 1012 Elf_Addr target; 1013 RtldLockState lockstate; 1014 1015 rlock_acquire(rtld_bind_lock, &lockstate); 1016 if (sigsetjmp(lockstate.env, 0) != 0) 1017 lock_upgrade(rtld_bind_lock, &lockstate); 1018 if (obj->pltrel) 1019 rel = (const Elf_Rel *)((const char *)obj->pltrel + reloff); 1020 else 1021 rel = (const Elf_Rel *)((const char *)obj->pltrela + reloff); 1022 1023 where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 1024 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, 1025 NULL, &lockstate); 1026 if (def == NULL) 1027 rtld_die(); 1028 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 1029 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 1030 else 1031 target = (Elf_Addr)(defobj->relocbase + def->st_value); 1032 1033 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 1034 defobj->strtab + def->st_name, 1035 obj->path == NULL ? NULL : basename(obj->path), 1036 (void *)target, 1037 defobj->path == NULL ? NULL : basename(defobj->path)); 1038 1039 /* 1040 * Write the new contents for the jmpslot. Note that depending on 1041 * architecture, the value which we need to return back to the 1042 * lazy binding trampoline may or may not be the target 1043 * address. The value returned from reloc_jmpslot() is the value 1044 * that the trampoline needs. 1045 */ 1046 target = reloc_jmpslot(where, target, defobj, obj, rel); 1047 lock_release(rtld_bind_lock, &lockstate); 1048 return (target); 1049 } 1050 1051 /* 1052 * Error reporting function. Use it like printf. If formats the message 1053 * into a buffer, and sets things up so that the next call to dlerror() 1054 * will return the message. 1055 */ 1056 void 1057 _rtld_error(const char *fmt, ...) 1058 { 1059 va_list ap; 1060 1061 va_start(ap, fmt); 1062 rtld_vsnprintf(lockinfo.dlerror_loc(), lockinfo.dlerror_loc_sz, 1063 fmt, ap); 1064 va_end(ap); 1065 *lockinfo.dlerror_seen() = 0; 1066 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, lockinfo.dlerror_loc()); 1067 } 1068 1069 /* 1070 * Return a dynamically-allocated copy of the current error message, if any. 1071 */ 1072 static struct dlerror_save * 1073 errmsg_save(void) 1074 { 1075 struct dlerror_save *res; 1076 1077 res = xmalloc(sizeof(*res)); 1078 res->seen = *lockinfo.dlerror_seen(); 1079 if (res->seen == 0) 1080 res->msg = xstrdup(lockinfo.dlerror_loc()); 1081 return (res); 1082 } 1083 1084 /* 1085 * Restore the current error message from a copy which was previously saved 1086 * by errmsg_save(). The copy is freed. 1087 */ 1088 static void 1089 errmsg_restore(struct dlerror_save *saved_msg) 1090 { 1091 if (saved_msg == NULL || saved_msg->seen == 1) { 1092 *lockinfo.dlerror_seen() = 1; 1093 } else { 1094 *lockinfo.dlerror_seen() = 0; 1095 strlcpy(lockinfo.dlerror_loc(), saved_msg->msg, 1096 lockinfo.dlerror_loc_sz); 1097 free(saved_msg->msg); 1098 } 1099 free(saved_msg); 1100 } 1101 1102 static const char * 1103 basename(const char *name) 1104 { 1105 const char *p; 1106 1107 p = strrchr(name, '/'); 1108 return (p != NULL ? p + 1 : name); 1109 } 1110 1111 static struct utsname uts; 1112 1113 static char * 1114 origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 1115 const char *subst, bool may_free) 1116 { 1117 char *p, *p1, *res, *resp; 1118 int subst_len, kw_len, subst_count, old_len, new_len; 1119 1120 kw_len = strlen(kw); 1121 1122 /* 1123 * First, count the number of the keyword occurrences, to 1124 * preallocate the final string. 1125 */ 1126 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 1127 p1 = strstr(p, kw); 1128 if (p1 == NULL) 1129 break; 1130 } 1131 1132 /* 1133 * If the keyword is not found, just return. 1134 * 1135 * Return non-substituted string if resolution failed. We 1136 * cannot do anything more reasonable, the failure mode of the 1137 * caller is unresolved library anyway. 1138 */ 1139 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 1140 return (may_free ? real : xstrdup(real)); 1141 if (obj != NULL) 1142 subst = obj->origin_path; 1143 1144 /* 1145 * There is indeed something to substitute. Calculate the 1146 * length of the resulting string, and allocate it. 1147 */ 1148 subst_len = strlen(subst); 1149 old_len = strlen(real); 1150 new_len = old_len + (subst_len - kw_len) * subst_count; 1151 res = xmalloc(new_len + 1); 1152 1153 /* 1154 * Now, execute the substitution loop. 1155 */ 1156 for (p = real, resp = res, *resp = '\0';;) { 1157 p1 = strstr(p, kw); 1158 if (p1 != NULL) { 1159 /* Copy the prefix before keyword. */ 1160 memcpy(resp, p, p1 - p); 1161 resp += p1 - p; 1162 /* Keyword replacement. */ 1163 memcpy(resp, subst, subst_len); 1164 resp += subst_len; 1165 *resp = '\0'; 1166 p = p1 + kw_len; 1167 } else 1168 break; 1169 } 1170 1171 /* Copy to the end of string and finish. */ 1172 strcat(resp, p); 1173 if (may_free) 1174 free(real); 1175 return (res); 1176 } 1177 1178 static const struct { 1179 const char *kw; 1180 bool pass_obj; 1181 const char *subst; 1182 } tokens[] = { 1183 { .kw = "$ORIGIN", .pass_obj = true, .subst = NULL }, 1184 { .kw = "${ORIGIN}", .pass_obj = true, .subst = NULL }, 1185 { .kw = "$OSNAME", .pass_obj = false, .subst = uts.sysname }, 1186 { .kw = "${OSNAME}", .pass_obj = false, .subst = uts.sysname }, 1187 { .kw = "$OSREL", .pass_obj = false, .subst = uts.release }, 1188 { .kw = "${OSREL}", .pass_obj = false, .subst = uts.release }, 1189 { .kw = "$PLATFORM", .pass_obj = false, .subst = uts.machine }, 1190 { .kw = "${PLATFORM}", .pass_obj = false, .subst = uts.machine }, 1191 }; 1192 1193 static char * 1194 origin_subst(Obj_Entry *obj, const char *real) 1195 { 1196 char *res; 1197 int i; 1198 1199 if (obj == NULL || !trust) 1200 return (xstrdup(real)); 1201 if (uts.sysname[0] == '\0') { 1202 if (uname(&uts) != 0) { 1203 _rtld_error("utsname failed: %d", errno); 1204 return (NULL); 1205 } 1206 } 1207 1208 /* __DECONST is safe here since without may_free real is unchanged */ 1209 res = __DECONST(char *, real); 1210 for (i = 0; i < (int)nitems(tokens); i++) { 1211 res = origin_subst_one(tokens[i].pass_obj ? obj : NULL, 1212 res, tokens[i].kw, tokens[i].subst, i == 0); 1213 } 1214 return (res); 1215 } 1216 1217 void 1218 rtld_die(void) 1219 { 1220 const char *msg = dlerror(); 1221 1222 if (msg == NULL) 1223 msg = "Fatal error"; 1224 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": "); 1225 rtld_fdputstr(STDERR_FILENO, msg); 1226 rtld_fdputchar(STDERR_FILENO, '\n'); 1227 _exit(1); 1228 } 1229 1230 /* 1231 * Process a shared object's DYNAMIC section, and save the important 1232 * information in its Obj_Entry structure. 1233 */ 1234 static void 1235 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 1236 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 1237 { 1238 const Elf_Dyn *dynp; 1239 Needed_Entry **needed_tail = &obj->needed; 1240 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 1241 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 1242 const Elf_Hashelt *hashtab; 1243 const Elf32_Word *hashval; 1244 Elf32_Word bkt, nmaskwords; 1245 int bloom_size32; 1246 int plttype = DT_REL; 1247 1248 *dyn_rpath = NULL; 1249 *dyn_soname = NULL; 1250 *dyn_runpath = NULL; 1251 1252 obj->bind_now = false; 1253 dynp = obj->dynamic; 1254 if (dynp == NULL) 1255 return; 1256 for (; dynp->d_tag != DT_NULL; dynp++) { 1257 switch (dynp->d_tag) { 1258 1259 case DT_REL: 1260 obj->rel = (const Elf_Rel *)(obj->relocbase + dynp->d_un.d_ptr); 1261 break; 1262 1263 case DT_RELSZ: 1264 obj->relsize = dynp->d_un.d_val; 1265 break; 1266 1267 case DT_RELENT: 1268 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 1269 break; 1270 1271 case DT_JMPREL: 1272 obj->pltrel = (const Elf_Rel *) 1273 (obj->relocbase + dynp->d_un.d_ptr); 1274 break; 1275 1276 case DT_PLTRELSZ: 1277 obj->pltrelsize = dynp->d_un.d_val; 1278 break; 1279 1280 case DT_RELA: 1281 obj->rela = (const Elf_Rela *)(obj->relocbase + dynp->d_un.d_ptr); 1282 break; 1283 1284 case DT_RELASZ: 1285 obj->relasize = dynp->d_un.d_val; 1286 break; 1287 1288 case DT_RELAENT: 1289 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 1290 break; 1291 1292 case DT_RELR: 1293 obj->relr = (const Elf_Relr *)(obj->relocbase + dynp->d_un.d_ptr); 1294 break; 1295 1296 case DT_RELRSZ: 1297 obj->relrsize = dynp->d_un.d_val; 1298 break; 1299 1300 case DT_RELRENT: 1301 assert(dynp->d_un.d_val == sizeof(Elf_Relr)); 1302 break; 1303 1304 case DT_PLTREL: 1305 plttype = dynp->d_un.d_val; 1306 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 1307 break; 1308 1309 case DT_SYMTAB: 1310 obj->symtab = (const Elf_Sym *) 1311 (obj->relocbase + dynp->d_un.d_ptr); 1312 break; 1313 1314 case DT_SYMENT: 1315 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 1316 break; 1317 1318 case DT_STRTAB: 1319 obj->strtab = (const char *)(obj->relocbase + dynp->d_un.d_ptr); 1320 break; 1321 1322 case DT_STRSZ: 1323 obj->strsize = dynp->d_un.d_val; 1324 break; 1325 1326 case DT_VERNEED: 1327 obj->verneed = (const Elf_Verneed *)(obj->relocbase + 1328 dynp->d_un.d_val); 1329 break; 1330 1331 case DT_VERNEEDNUM: 1332 obj->verneednum = dynp->d_un.d_val; 1333 break; 1334 1335 case DT_VERDEF: 1336 obj->verdef = (const Elf_Verdef *)(obj->relocbase + 1337 dynp->d_un.d_val); 1338 break; 1339 1340 case DT_VERDEFNUM: 1341 obj->verdefnum = dynp->d_un.d_val; 1342 break; 1343 1344 case DT_VERSYM: 1345 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1346 dynp->d_un.d_val); 1347 break; 1348 1349 case DT_HASH: 1350 { 1351 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1352 dynp->d_un.d_ptr); 1353 obj->nbuckets = hashtab[0]; 1354 obj->nchains = hashtab[1]; 1355 obj->buckets = hashtab + 2; 1356 obj->chains = obj->buckets + obj->nbuckets; 1357 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1358 obj->buckets != NULL; 1359 } 1360 break; 1361 1362 case DT_GNU_HASH: 1363 { 1364 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1365 dynp->d_un.d_ptr); 1366 obj->nbuckets_gnu = hashtab[0]; 1367 obj->symndx_gnu = hashtab[1]; 1368 nmaskwords = hashtab[2]; 1369 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1370 obj->maskwords_bm_gnu = nmaskwords - 1; 1371 obj->shift2_gnu = hashtab[3]; 1372 obj->bloom_gnu = (const Elf_Addr *)(hashtab + 4); 1373 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1374 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1375 obj->symndx_gnu; 1376 /* Number of bitmask words is required to be power of 2 */ 1377 obj->valid_hash_gnu = powerof2(nmaskwords) && 1378 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1379 } 1380 break; 1381 1382 case DT_NEEDED: 1383 if (!obj->rtld) { 1384 Needed_Entry *nep = NEW(Needed_Entry); 1385 nep->name = dynp->d_un.d_val; 1386 nep->obj = NULL; 1387 nep->next = NULL; 1388 1389 *needed_tail = nep; 1390 needed_tail = &nep->next; 1391 } 1392 break; 1393 1394 case DT_FILTER: 1395 if (!obj->rtld) { 1396 Needed_Entry *nep = NEW(Needed_Entry); 1397 nep->name = dynp->d_un.d_val; 1398 nep->obj = NULL; 1399 nep->next = NULL; 1400 1401 *needed_filtees_tail = nep; 1402 needed_filtees_tail = &nep->next; 1403 1404 if (obj->linkmap.l_refname == NULL) 1405 obj->linkmap.l_refname = (char *)dynp->d_un.d_val; 1406 } 1407 break; 1408 1409 case DT_AUXILIARY: 1410 if (!obj->rtld) { 1411 Needed_Entry *nep = NEW(Needed_Entry); 1412 nep->name = dynp->d_un.d_val; 1413 nep->obj = NULL; 1414 nep->next = NULL; 1415 1416 *needed_aux_filtees_tail = nep; 1417 needed_aux_filtees_tail = &nep->next; 1418 } 1419 break; 1420 1421 case DT_PLTGOT: 1422 obj->pltgot = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1423 break; 1424 1425 case DT_TEXTREL: 1426 obj->textrel = true; 1427 break; 1428 1429 case DT_SYMBOLIC: 1430 obj->symbolic = true; 1431 break; 1432 1433 case DT_RPATH: 1434 /* 1435 * We have to wait until later to process this, because we 1436 * might not have gotten the address of the string table yet. 1437 */ 1438 *dyn_rpath = dynp; 1439 break; 1440 1441 case DT_SONAME: 1442 *dyn_soname = dynp; 1443 break; 1444 1445 case DT_RUNPATH: 1446 *dyn_runpath = dynp; 1447 break; 1448 1449 case DT_INIT: 1450 obj->init = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1451 break; 1452 1453 case DT_PREINIT_ARRAY: 1454 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1455 break; 1456 1457 case DT_PREINIT_ARRAYSZ: 1458 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1459 break; 1460 1461 case DT_INIT_ARRAY: 1462 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1463 break; 1464 1465 case DT_INIT_ARRAYSZ: 1466 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1467 break; 1468 1469 case DT_FINI: 1470 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1471 break; 1472 1473 case DT_FINI_ARRAY: 1474 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1475 break; 1476 1477 case DT_FINI_ARRAYSZ: 1478 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1479 break; 1480 1481 case DT_DEBUG: 1482 if (!early) 1483 dbg("Filling in DT_DEBUG entry"); 1484 (__DECONST(Elf_Dyn *, dynp))->d_un.d_ptr = (Elf_Addr)&r_debug; 1485 break; 1486 1487 case DT_FLAGS: 1488 if (dynp->d_un.d_val & DF_ORIGIN) 1489 obj->z_origin = true; 1490 if (dynp->d_un.d_val & DF_SYMBOLIC) 1491 obj->symbolic = true; 1492 if (dynp->d_un.d_val & DF_TEXTREL) 1493 obj->textrel = true; 1494 if (dynp->d_un.d_val & DF_BIND_NOW) 1495 obj->bind_now = true; 1496 if (dynp->d_un.d_val & DF_STATIC_TLS) 1497 obj->static_tls = true; 1498 break; 1499 1500 #ifdef __powerpc__ 1501 #ifdef __powerpc64__ 1502 case DT_PPC64_GLINK: 1503 obj->glink = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1504 break; 1505 #else 1506 case DT_PPC_GOT: 1507 obj->gotptr = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1508 break; 1509 #endif 1510 #endif 1511 1512 case DT_FLAGS_1: 1513 if (dynp->d_un.d_val & DF_1_NOOPEN) 1514 obj->z_noopen = true; 1515 if (dynp->d_un.d_val & DF_1_ORIGIN) 1516 obj->z_origin = true; 1517 if (dynp->d_un.d_val & DF_1_GLOBAL) 1518 obj->z_global = true; 1519 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1520 obj->bind_now = true; 1521 if (dynp->d_un.d_val & DF_1_NODELETE) 1522 obj->z_nodelete = true; 1523 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1524 obj->z_loadfltr = true; 1525 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1526 obj->z_interpose = true; 1527 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1528 obj->z_nodeflib = true; 1529 if (dynp->d_un.d_val & DF_1_PIE) 1530 obj->z_pie = true; 1531 break; 1532 1533 default: 1534 if (!early) { 1535 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1536 (long)dynp->d_tag); 1537 } 1538 break; 1539 } 1540 } 1541 1542 obj->traced = false; 1543 1544 if (plttype == DT_RELA) { 1545 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1546 obj->pltrel = NULL; 1547 obj->pltrelasize = obj->pltrelsize; 1548 obj->pltrelsize = 0; 1549 } 1550 1551 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1552 if (obj->valid_hash_sysv) 1553 obj->dynsymcount = obj->nchains; 1554 else if (obj->valid_hash_gnu) { 1555 obj->dynsymcount = 0; 1556 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1557 if (obj->buckets_gnu[bkt] == 0) 1558 continue; 1559 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1560 do 1561 obj->dynsymcount++; 1562 while ((*hashval++ & 1u) == 0); 1563 } 1564 obj->dynsymcount += obj->symndx_gnu; 1565 } 1566 1567 if (obj->linkmap.l_refname != NULL) 1568 obj->linkmap.l_refname = obj->strtab + (unsigned long)obj-> 1569 linkmap.l_refname; 1570 } 1571 1572 static bool 1573 obj_resolve_origin(Obj_Entry *obj) 1574 { 1575 1576 if (obj->origin_path != NULL) 1577 return (true); 1578 obj->origin_path = xmalloc(PATH_MAX); 1579 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1580 } 1581 1582 static bool 1583 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1584 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1585 { 1586 1587 if (obj->z_origin && !obj_resolve_origin(obj)) 1588 return (false); 1589 1590 if (dyn_runpath != NULL) { 1591 obj->runpath = (const char *)obj->strtab + dyn_runpath->d_un.d_val; 1592 obj->runpath = origin_subst(obj, obj->runpath); 1593 } else if (dyn_rpath != NULL) { 1594 obj->rpath = (const char *)obj->strtab + dyn_rpath->d_un.d_val; 1595 obj->rpath = origin_subst(obj, obj->rpath); 1596 } 1597 if (dyn_soname != NULL) 1598 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1599 return (true); 1600 } 1601 1602 static bool 1603 digest_dynamic(Obj_Entry *obj, int early) 1604 { 1605 const Elf_Dyn *dyn_rpath; 1606 const Elf_Dyn *dyn_soname; 1607 const Elf_Dyn *dyn_runpath; 1608 1609 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1610 return (digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath)); 1611 } 1612 1613 /* 1614 * Process a shared object's program header. This is used only for the 1615 * main program, when the kernel has already loaded the main program 1616 * into memory before calling the dynamic linker. It creates and 1617 * returns an Obj_Entry structure. 1618 */ 1619 static Obj_Entry * 1620 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1621 { 1622 Obj_Entry *obj; 1623 const Elf_Phdr *phlimit = phdr + phnum; 1624 const Elf_Phdr *ph; 1625 Elf_Addr note_start, note_end; 1626 int nsegs = 0; 1627 1628 obj = obj_new(); 1629 for (ph = phdr; ph < phlimit; ph++) { 1630 if (ph->p_type != PT_PHDR) 1631 continue; 1632 1633 obj->phdr = phdr; 1634 obj->phsize = ph->p_memsz; 1635 obj->relocbase = __DECONST(char *, phdr) - ph->p_vaddr; 1636 break; 1637 } 1638 1639 obj->stack_flags = PF_X | PF_R | PF_W; 1640 1641 for (ph = phdr; ph < phlimit; ph++) { 1642 switch (ph->p_type) { 1643 1644 case PT_INTERP: 1645 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1646 break; 1647 1648 case PT_LOAD: 1649 if (nsegs == 0) { /* First load segment */ 1650 obj->vaddrbase = trunc_page(ph->p_vaddr); 1651 obj->mapbase = obj->vaddrbase + obj->relocbase; 1652 } else { /* Last load segment */ 1653 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1654 obj->vaddrbase; 1655 } 1656 nsegs++; 1657 break; 1658 1659 case PT_DYNAMIC: 1660 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1661 break; 1662 1663 case PT_TLS: 1664 obj->tlsindex = 1; 1665 obj->tlssize = ph->p_memsz; 1666 obj->tlsalign = ph->p_align; 1667 obj->tlsinitsize = ph->p_filesz; 1668 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1669 obj->tlspoffset = ph->p_offset; 1670 break; 1671 1672 case PT_GNU_STACK: 1673 obj->stack_flags = ph->p_flags; 1674 break; 1675 1676 case PT_GNU_RELRO: 1677 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1678 obj->relro_size = trunc_page(ph->p_vaddr + ph->p_memsz) - 1679 trunc_page(ph->p_vaddr); 1680 break; 1681 1682 case PT_NOTE: 1683 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1684 note_end = note_start + ph->p_filesz; 1685 digest_notes(obj, note_start, note_end); 1686 break; 1687 } 1688 } 1689 if (nsegs < 1) { 1690 _rtld_error("%s: too few PT_LOAD segments", path); 1691 return (NULL); 1692 } 1693 1694 obj->entry = entry; 1695 return (obj); 1696 } 1697 1698 void 1699 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1700 { 1701 const Elf_Note *note; 1702 const char *note_name; 1703 uintptr_t p; 1704 1705 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1706 note = (const Elf_Note *)((const char *)(note + 1) + 1707 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1708 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1709 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1710 note->n_descsz != sizeof(int32_t)) 1711 continue; 1712 if (note->n_type != NT_FREEBSD_ABI_TAG && 1713 note->n_type != NT_FREEBSD_FEATURE_CTL && 1714 note->n_type != NT_FREEBSD_NOINIT_TAG) 1715 continue; 1716 note_name = (const char *)(note + 1); 1717 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1718 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1719 continue; 1720 switch (note->n_type) { 1721 case NT_FREEBSD_ABI_TAG: 1722 /* FreeBSD osrel note */ 1723 p = (uintptr_t)(note + 1); 1724 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1725 obj->osrel = *(const int32_t *)(p); 1726 dbg("note osrel %d", obj->osrel); 1727 break; 1728 case NT_FREEBSD_FEATURE_CTL: 1729 /* FreeBSD ABI feature control note */ 1730 p = (uintptr_t)(note + 1); 1731 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1732 obj->fctl0 = *(const uint32_t *)(p); 1733 dbg("note fctl0 %#x", obj->fctl0); 1734 break; 1735 case NT_FREEBSD_NOINIT_TAG: 1736 /* FreeBSD 'crt does not call init' note */ 1737 obj->crt_no_init = true; 1738 dbg("note crt_no_init"); 1739 break; 1740 } 1741 } 1742 } 1743 1744 static Obj_Entry * 1745 dlcheck(void *handle) 1746 { 1747 Obj_Entry *obj; 1748 1749 TAILQ_FOREACH(obj, &obj_list, next) { 1750 if (obj == (Obj_Entry *) handle) 1751 break; 1752 } 1753 1754 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1755 _rtld_error("Invalid shared object handle %p", handle); 1756 return (NULL); 1757 } 1758 return (obj); 1759 } 1760 1761 /* 1762 * If the given object is already in the donelist, return true. Otherwise 1763 * add the object to the list and return false. 1764 */ 1765 static bool 1766 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1767 { 1768 unsigned int i; 1769 1770 for (i = 0; i < dlp->num_used; i++) 1771 if (dlp->objs[i] == obj) 1772 return (true); 1773 /* 1774 * Our donelist allocation should always be sufficient. But if 1775 * our threads locking isn't working properly, more shared objects 1776 * could have been loaded since we allocated the list. That should 1777 * never happen, but we'll handle it properly just in case it does. 1778 */ 1779 if (dlp->num_used < dlp->num_alloc) 1780 dlp->objs[dlp->num_used++] = obj; 1781 return (false); 1782 } 1783 1784 /* 1785 * Hash function for symbol table lookup. Don't even think about changing 1786 * this. It is specified by the System V ABI. 1787 */ 1788 unsigned long 1789 elf_hash(const char *name) 1790 { 1791 const unsigned char *p = (const unsigned char *) name; 1792 unsigned long h = 0; 1793 unsigned long g; 1794 1795 while (*p != '\0') { 1796 h = (h << 4) + *p++; 1797 if ((g = h & 0xf0000000) != 0) 1798 h ^= g >> 24; 1799 h &= ~g; 1800 } 1801 return (h); 1802 } 1803 1804 /* 1805 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1806 * unsigned in case it's implemented with a wider type. 1807 */ 1808 static uint32_t 1809 gnu_hash(const char *s) 1810 { 1811 uint32_t h; 1812 unsigned char c; 1813 1814 h = 5381; 1815 for (c = *s; c != '\0'; c = *++s) 1816 h = h * 33 + c; 1817 return (h & 0xffffffff); 1818 } 1819 1820 1821 /* 1822 * Find the library with the given name, and return its full pathname. 1823 * The returned string is dynamically allocated. Generates an error 1824 * message and returns NULL if the library cannot be found. 1825 * 1826 * If the second argument is non-NULL, then it refers to an already- 1827 * loaded shared object, whose library search path will be searched. 1828 * 1829 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1830 * descriptor (which is close-on-exec) will be passed out via the third 1831 * argument. 1832 * 1833 * The search order is: 1834 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1835 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1836 * LD_LIBRARY_PATH 1837 * DT_RUNPATH in the referencing file 1838 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1839 * from list) 1840 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1841 * 1842 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1843 */ 1844 static char * 1845 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1846 { 1847 char *pathname, *refobj_path; 1848 const char *name; 1849 bool nodeflib, objgiven; 1850 1851 objgiven = refobj != NULL; 1852 1853 if (libmap_disable || !objgiven || 1854 (name = lm_find(refobj->path, xname)) == NULL) 1855 name = xname; 1856 1857 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 1858 if (name[0] != '/' && !trust) { 1859 _rtld_error("Absolute pathname required " 1860 "for shared object \"%s\"", name); 1861 return (NULL); 1862 } 1863 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1864 __DECONST(char *, name))); 1865 } 1866 1867 dbg(" Searching for \"%s\"", name); 1868 refobj_path = objgiven ? refobj->path : NULL; 1869 1870 /* 1871 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1872 * back to pre-conforming behaviour if user requested so with 1873 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1874 * nodeflib. 1875 */ 1876 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1877 pathname = search_library_path(name, ld_library_path, 1878 refobj_path, fdp); 1879 if (pathname != NULL) 1880 return (pathname); 1881 if (refobj != NULL) { 1882 pathname = search_library_path(name, refobj->rpath, 1883 refobj_path, fdp); 1884 if (pathname != NULL) 1885 return (pathname); 1886 } 1887 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1888 if (pathname != NULL) 1889 return (pathname); 1890 pathname = search_library_path(name, gethints(false), 1891 refobj_path, fdp); 1892 if (pathname != NULL) 1893 return (pathname); 1894 pathname = search_library_path(name, ld_standard_library_path, 1895 refobj_path, fdp); 1896 if (pathname != NULL) 1897 return (pathname); 1898 } else { 1899 nodeflib = objgiven ? refobj->z_nodeflib : false; 1900 if (objgiven) { 1901 pathname = search_library_path(name, refobj->rpath, 1902 refobj->path, fdp); 1903 if (pathname != NULL) 1904 return (pathname); 1905 } 1906 if (objgiven && refobj->runpath == NULL && refobj != obj_main) { 1907 pathname = search_library_path(name, obj_main->rpath, 1908 refobj_path, fdp); 1909 if (pathname != NULL) 1910 return (pathname); 1911 } 1912 pathname = search_library_path(name, ld_library_path, 1913 refobj_path, fdp); 1914 if (pathname != NULL) 1915 return (pathname); 1916 if (objgiven) { 1917 pathname = search_library_path(name, refobj->runpath, 1918 refobj_path, fdp); 1919 if (pathname != NULL) 1920 return (pathname); 1921 } 1922 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1923 if (pathname != NULL) 1924 return (pathname); 1925 pathname = search_library_path(name, gethints(nodeflib), 1926 refobj_path, fdp); 1927 if (pathname != NULL) 1928 return (pathname); 1929 if (objgiven && !nodeflib) { 1930 pathname = search_library_path(name, 1931 ld_standard_library_path, refobj_path, fdp); 1932 if (pathname != NULL) 1933 return (pathname); 1934 } 1935 } 1936 1937 if (objgiven && refobj->path != NULL) { 1938 _rtld_error("Shared object \"%s\" not found, " 1939 "required by \"%s\"", name, basename(refobj->path)); 1940 } else { 1941 _rtld_error("Shared object \"%s\" not found", name); 1942 } 1943 return (NULL); 1944 } 1945 1946 /* 1947 * Given a symbol number in a referencing object, find the corresponding 1948 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1949 * no definition was found. Returns a pointer to the Obj_Entry of the 1950 * defining object via the reference parameter DEFOBJ_OUT. 1951 */ 1952 const Elf_Sym * 1953 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1954 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1955 RtldLockState *lockstate) 1956 { 1957 const Elf_Sym *ref; 1958 const Elf_Sym *def; 1959 const Obj_Entry *defobj; 1960 const Ver_Entry *ve; 1961 SymLook req; 1962 const char *name; 1963 int res; 1964 1965 /* 1966 * If we have already found this symbol, get the information from 1967 * the cache. 1968 */ 1969 if (symnum >= refobj->dynsymcount) 1970 return (NULL); /* Bad object */ 1971 if (cache != NULL && cache[symnum].sym != NULL) { 1972 *defobj_out = cache[symnum].obj; 1973 return (cache[symnum].sym); 1974 } 1975 1976 ref = refobj->symtab + symnum; 1977 name = refobj->strtab + ref->st_name; 1978 def = NULL; 1979 defobj = NULL; 1980 ve = NULL; 1981 1982 /* 1983 * We don't have to do a full scale lookup if the symbol is local. 1984 * We know it will bind to the instance in this load module; to 1985 * which we already have a pointer (ie ref). By not doing a lookup, 1986 * we not only improve performance, but it also avoids unresolvable 1987 * symbols when local symbols are not in the hash table. This has 1988 * been seen with the ia64 toolchain. 1989 */ 1990 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1991 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1992 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1993 symnum); 1994 } 1995 symlook_init(&req, name); 1996 req.flags = flags; 1997 ve = req.ventry = fetch_ventry(refobj, symnum); 1998 req.lockstate = lockstate; 1999 res = symlook_default(&req, refobj); 2000 if (res == 0) { 2001 def = req.sym_out; 2002 defobj = req.defobj_out; 2003 } 2004 } else { 2005 def = ref; 2006 defobj = refobj; 2007 } 2008 2009 /* 2010 * If we found no definition and the reference is weak, treat the 2011 * symbol as having the value zero. 2012 */ 2013 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 2014 def = &sym_zero; 2015 defobj = obj_main; 2016 } 2017 2018 if (def != NULL) { 2019 *defobj_out = defobj; 2020 /* Record the information in the cache to avoid subsequent lookups. */ 2021 if (cache != NULL) { 2022 cache[symnum].sym = def; 2023 cache[symnum].obj = defobj; 2024 } 2025 } else { 2026 if (refobj != &obj_rtld) 2027 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name, 2028 ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); 2029 } 2030 return (def); 2031 } 2032 2033 /* 2034 * Return the search path from the ldconfig hints file, reading it if 2035 * necessary. If nostdlib is true, then the default search paths are 2036 * not added to result. 2037 * 2038 * Returns NULL if there are problems with the hints file, 2039 * or if the search path there is empty. 2040 */ 2041 static const char * 2042 gethints(bool nostdlib) 2043 { 2044 static char *filtered_path; 2045 static const char *hints; 2046 static struct elfhints_hdr hdr; 2047 struct fill_search_info_args sargs, hargs; 2048 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 2049 struct dl_serpath *SLPpath, *hintpath; 2050 char *p; 2051 struct stat hint_stat; 2052 unsigned int SLPndx, hintndx, fndx, fcount; 2053 int fd; 2054 size_t flen; 2055 uint32_t dl; 2056 bool skip; 2057 2058 /* First call, read the hints file */ 2059 if (hints == NULL) { 2060 /* Keep from trying again in case the hints file is bad. */ 2061 hints = ""; 2062 2063 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 2064 return (NULL); 2065 2066 /* 2067 * Check of hdr.dirlistlen value against type limit 2068 * intends to pacify static analyzers. Further 2069 * paranoia leads to checks that dirlist is fully 2070 * contained in the file range. 2071 */ 2072 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 2073 hdr.magic != ELFHINTS_MAGIC || 2074 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 2075 fstat(fd, &hint_stat) == -1) { 2076 cleanup1: 2077 close(fd); 2078 hdr.dirlistlen = 0; 2079 return (NULL); 2080 } 2081 dl = hdr.strtab; 2082 if (dl + hdr.dirlist < dl) 2083 goto cleanup1; 2084 dl += hdr.dirlist; 2085 if (dl + hdr.dirlistlen < dl) 2086 goto cleanup1; 2087 dl += hdr.dirlistlen; 2088 if (dl > hint_stat.st_size) 2089 goto cleanup1; 2090 p = xmalloc(hdr.dirlistlen + 1); 2091 if (pread(fd, p, hdr.dirlistlen + 1, 2092 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 || 2093 p[hdr.dirlistlen] != '\0') { 2094 free(p); 2095 goto cleanup1; 2096 } 2097 hints = p; 2098 close(fd); 2099 } 2100 2101 /* 2102 * If caller agreed to receive list which includes the default 2103 * paths, we are done. Otherwise, if we still did not 2104 * calculated filtered result, do it now. 2105 */ 2106 if (!nostdlib) 2107 return (hints[0] != '\0' ? hints : NULL); 2108 if (filtered_path != NULL) 2109 goto filt_ret; 2110 2111 /* 2112 * Obtain the list of all configured search paths, and the 2113 * list of the default paths. 2114 * 2115 * First estimate the size of the results. 2116 */ 2117 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2118 smeta.dls_cnt = 0; 2119 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2120 hmeta.dls_cnt = 0; 2121 2122 sargs.request = RTLD_DI_SERINFOSIZE; 2123 sargs.serinfo = &smeta; 2124 hargs.request = RTLD_DI_SERINFOSIZE; 2125 hargs.serinfo = &hmeta; 2126 2127 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 2128 &sargs); 2129 path_enumerate(hints, fill_search_info, NULL, &hargs); 2130 2131 SLPinfo = xmalloc(smeta.dls_size); 2132 hintinfo = xmalloc(hmeta.dls_size); 2133 2134 /* 2135 * Next fetch both sets of paths. 2136 */ 2137 sargs.request = RTLD_DI_SERINFO; 2138 sargs.serinfo = SLPinfo; 2139 sargs.serpath = &SLPinfo->dls_serpath[0]; 2140 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 2141 2142 hargs.request = RTLD_DI_SERINFO; 2143 hargs.serinfo = hintinfo; 2144 hargs.serpath = &hintinfo->dls_serpath[0]; 2145 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 2146 2147 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 2148 &sargs); 2149 path_enumerate(hints, fill_search_info, NULL, &hargs); 2150 2151 /* 2152 * Now calculate the difference between two sets, by excluding 2153 * standard paths from the full set. 2154 */ 2155 fndx = 0; 2156 fcount = 0; 2157 filtered_path = xmalloc(hdr.dirlistlen + 1); 2158 hintpath = &hintinfo->dls_serpath[0]; 2159 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 2160 skip = false; 2161 SLPpath = &SLPinfo->dls_serpath[0]; 2162 /* 2163 * Check each standard path against current. 2164 */ 2165 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 2166 /* matched, skip the path */ 2167 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 2168 skip = true; 2169 break; 2170 } 2171 } 2172 if (skip) 2173 continue; 2174 /* 2175 * Not matched against any standard path, add the path 2176 * to result. Separate consequtive paths with ':'. 2177 */ 2178 if (fcount > 0) { 2179 filtered_path[fndx] = ':'; 2180 fndx++; 2181 } 2182 fcount++; 2183 flen = strlen(hintpath->dls_name); 2184 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 2185 fndx += flen; 2186 } 2187 filtered_path[fndx] = '\0'; 2188 2189 free(SLPinfo); 2190 free(hintinfo); 2191 2192 filt_ret: 2193 return (filtered_path[0] != '\0' ? filtered_path : NULL); 2194 } 2195 2196 static void 2197 init_dag(Obj_Entry *root) 2198 { 2199 const Needed_Entry *needed; 2200 const Objlist_Entry *elm; 2201 DoneList donelist; 2202 2203 if (root->dag_inited) 2204 return; 2205 donelist_init(&donelist); 2206 2207 /* Root object belongs to own DAG. */ 2208 objlist_push_tail(&root->dldags, root); 2209 objlist_push_tail(&root->dagmembers, root); 2210 donelist_check(&donelist, root); 2211 2212 /* 2213 * Add dependencies of root object to DAG in breadth order 2214 * by exploiting the fact that each new object get added 2215 * to the tail of the dagmembers list. 2216 */ 2217 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2218 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 2219 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 2220 continue; 2221 objlist_push_tail(&needed->obj->dldags, root); 2222 objlist_push_tail(&root->dagmembers, needed->obj); 2223 } 2224 } 2225 root->dag_inited = true; 2226 } 2227 2228 static void 2229 init_marker(Obj_Entry *marker) 2230 { 2231 2232 bzero(marker, sizeof(*marker)); 2233 marker->marker = true; 2234 } 2235 2236 Obj_Entry * 2237 globallist_curr(const Obj_Entry *obj) 2238 { 2239 2240 for (;;) { 2241 if (obj == NULL) 2242 return (NULL); 2243 if (!obj->marker) 2244 return (__DECONST(Obj_Entry *, obj)); 2245 obj = TAILQ_PREV(obj, obj_entry_q, next); 2246 } 2247 } 2248 2249 Obj_Entry * 2250 globallist_next(const Obj_Entry *obj) 2251 { 2252 2253 for (;;) { 2254 obj = TAILQ_NEXT(obj, next); 2255 if (obj == NULL) 2256 return (NULL); 2257 if (!obj->marker) 2258 return (__DECONST(Obj_Entry *, obj)); 2259 } 2260 } 2261 2262 /* Prevent the object from being unmapped while the bind lock is dropped. */ 2263 static void 2264 hold_object(Obj_Entry *obj) 2265 { 2266 2267 obj->holdcount++; 2268 } 2269 2270 static void 2271 unhold_object(Obj_Entry *obj) 2272 { 2273 2274 assert(obj->holdcount > 0); 2275 if (--obj->holdcount == 0 && obj->unholdfree) 2276 release_object(obj); 2277 } 2278 2279 static void 2280 process_z(Obj_Entry *root) 2281 { 2282 const Objlist_Entry *elm; 2283 Obj_Entry *obj; 2284 2285 /* 2286 * Walk over object DAG and process every dependent object 2287 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 2288 * to grow their own DAG. 2289 * 2290 * For DF_1_GLOBAL, DAG is required for symbol lookups in 2291 * symlook_global() to work. 2292 * 2293 * For DF_1_NODELETE, the DAG should have its reference upped. 2294 */ 2295 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2296 obj = elm->obj; 2297 if (obj == NULL) 2298 continue; 2299 if (obj->z_nodelete && !obj->ref_nodel) { 2300 dbg("obj %s -z nodelete", obj->path); 2301 init_dag(obj); 2302 ref_dag(obj); 2303 obj->ref_nodel = true; 2304 } 2305 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 2306 dbg("obj %s -z global", obj->path); 2307 objlist_push_tail(&list_global, obj); 2308 init_dag(obj); 2309 } 2310 } 2311 } 2312 2313 static void 2314 parse_rtld_phdr(Obj_Entry *obj) 2315 { 2316 const Elf_Phdr *ph; 2317 Elf_Addr note_start, note_end; 2318 2319 obj->stack_flags = PF_X | PF_R | PF_W; 2320 for (ph = obj->phdr; (const char *)ph < (const char *)obj->phdr + 2321 obj->phsize; ph++) { 2322 switch (ph->p_type) { 2323 case PT_GNU_STACK: 2324 obj->stack_flags = ph->p_flags; 2325 break; 2326 case PT_GNU_RELRO: 2327 obj->relro_page = obj->relocbase + 2328 trunc_page(ph->p_vaddr); 2329 obj->relro_size = round_page(ph->p_memsz); 2330 break; 2331 case PT_NOTE: 2332 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 2333 note_end = note_start + ph->p_filesz; 2334 digest_notes(obj, note_start, note_end); 2335 break; 2336 } 2337 } 2338 } 2339 2340 /* 2341 * Initialize the dynamic linker. The argument is the address at which 2342 * the dynamic linker has been mapped into memory. The primary task of 2343 * this function is to relocate the dynamic linker. 2344 */ 2345 static void 2346 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 2347 { 2348 Obj_Entry objtmp; /* Temporary rtld object */ 2349 const Elf_Ehdr *ehdr; 2350 const Elf_Dyn *dyn_rpath; 2351 const Elf_Dyn *dyn_soname; 2352 const Elf_Dyn *dyn_runpath; 2353 2354 #ifdef RTLD_INIT_PAGESIZES_EARLY 2355 /* The page size is required by the dynamic memory allocator. */ 2356 init_pagesizes(aux_info); 2357 #endif 2358 2359 /* 2360 * Conjure up an Obj_Entry structure for the dynamic linker. 2361 * 2362 * The "path" member can't be initialized yet because string constants 2363 * cannot yet be accessed. Below we will set it correctly. 2364 */ 2365 memset(&objtmp, 0, sizeof(objtmp)); 2366 objtmp.path = NULL; 2367 objtmp.rtld = true; 2368 objtmp.mapbase = mapbase; 2369 #ifdef PIC 2370 objtmp.relocbase = mapbase; 2371 #endif 2372 2373 objtmp.dynamic = rtld_dynamic(&objtmp); 2374 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 2375 assert(objtmp.needed == NULL); 2376 assert(!objtmp.textrel); 2377 /* 2378 * Temporarily put the dynamic linker entry into the object list, so 2379 * that symbols can be found. 2380 */ 2381 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 2382 2383 ehdr = (Elf_Ehdr *)mapbase; 2384 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 2385 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 2386 2387 /* Initialize the object list. */ 2388 TAILQ_INIT(&obj_list); 2389 2390 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 2391 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 2392 2393 #ifndef RTLD_INIT_PAGESIZES_EARLY 2394 /* The page size is required by the dynamic memory allocator. */ 2395 init_pagesizes(aux_info); 2396 #endif 2397 2398 if (aux_info[AT_OSRELDATE] != NULL) 2399 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 2400 2401 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 2402 2403 /* Replace the path with a dynamically allocated copy. */ 2404 obj_rtld.path = xstrdup(ld_path_rtld); 2405 2406 parse_rtld_phdr(&obj_rtld); 2407 if (obj_enforce_relro(&obj_rtld) == -1) 2408 rtld_die(); 2409 2410 r_debug.r_version = R_DEBUG_VERSION; 2411 r_debug.r_brk = r_debug_state; 2412 r_debug.r_state = RT_CONSISTENT; 2413 r_debug.r_ldbase = obj_rtld.relocbase; 2414 } 2415 2416 /* 2417 * Retrieve the array of supported page sizes. The kernel provides the page 2418 * sizes in increasing order. 2419 */ 2420 static void 2421 init_pagesizes(Elf_Auxinfo **aux_info) 2422 { 2423 static size_t psa[MAXPAGESIZES]; 2424 int mib[2]; 2425 size_t len, size; 2426 2427 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 2428 NULL) { 2429 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 2430 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2431 } else { 2432 len = 2; 2433 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2434 size = sizeof(psa); 2435 else { 2436 /* As a fallback, retrieve the base page size. */ 2437 size = sizeof(psa[0]); 2438 if (aux_info[AT_PAGESZ] != NULL) { 2439 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2440 goto psa_filled; 2441 } else { 2442 mib[0] = CTL_HW; 2443 mib[1] = HW_PAGESIZE; 2444 len = 2; 2445 } 2446 } 2447 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2448 _rtld_error("sysctl for hw.pagesize(s) failed"); 2449 rtld_die(); 2450 } 2451 psa_filled: 2452 pagesizes = psa; 2453 } 2454 npagesizes = size / sizeof(pagesizes[0]); 2455 /* Discard any invalid entries at the end of the array. */ 2456 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2457 npagesizes--; 2458 } 2459 2460 /* 2461 * Add the init functions from a needed object list (and its recursive 2462 * needed objects) to "list". This is not used directly; it is a helper 2463 * function for initlist_add_objects(). The write lock must be held 2464 * when this function is called. 2465 */ 2466 static void 2467 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2468 { 2469 /* Recursively process the successor needed objects. */ 2470 if (needed->next != NULL) 2471 initlist_add_neededs(needed->next, list); 2472 2473 /* Process the current needed object. */ 2474 if (needed->obj != NULL) 2475 initlist_add_objects(needed->obj, needed->obj, list); 2476 } 2477 2478 /* 2479 * Scan all of the DAGs rooted in the range of objects from "obj" to 2480 * "tail" and add their init functions to "list". This recurses over 2481 * the DAGs and ensure the proper init ordering such that each object's 2482 * needed libraries are initialized before the object itself. At the 2483 * same time, this function adds the objects to the global finalization 2484 * list "list_fini" in the opposite order. The write lock must be 2485 * held when this function is called. 2486 */ 2487 static void 2488 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2489 { 2490 Obj_Entry *nobj; 2491 2492 if (obj->init_scanned || obj->init_done) 2493 return; 2494 obj->init_scanned = true; 2495 2496 /* Recursively process the successor objects. */ 2497 nobj = globallist_next(obj); 2498 if (nobj != NULL && obj != tail) 2499 initlist_add_objects(nobj, tail, list); 2500 2501 /* Recursively process the needed objects. */ 2502 if (obj->needed != NULL) 2503 initlist_add_neededs(obj->needed, list); 2504 if (obj->needed_filtees != NULL) 2505 initlist_add_neededs(obj->needed_filtees, list); 2506 if (obj->needed_aux_filtees != NULL) 2507 initlist_add_neededs(obj->needed_aux_filtees, list); 2508 2509 /* Add the object to the init list. */ 2510 objlist_push_tail(list, obj); 2511 2512 /* Add the object to the global fini list in the reverse order. */ 2513 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2514 && !obj->on_fini_list) { 2515 objlist_push_head(&list_fini, obj); 2516 obj->on_fini_list = true; 2517 } 2518 } 2519 2520 #ifndef FPTR_TARGET 2521 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 2522 #endif 2523 2524 static void 2525 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) 2526 { 2527 Needed_Entry *needed, *needed1; 2528 2529 for (needed = n; needed != NULL; needed = needed->next) { 2530 if (needed->obj != NULL) { 2531 dlclose_locked(needed->obj, lockstate); 2532 needed->obj = NULL; 2533 } 2534 } 2535 for (needed = n; needed != NULL; needed = needed1) { 2536 needed1 = needed->next; 2537 free(needed); 2538 } 2539 } 2540 2541 static void 2542 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) 2543 { 2544 2545 free_needed_filtees(obj->needed_filtees, lockstate); 2546 obj->needed_filtees = NULL; 2547 free_needed_filtees(obj->needed_aux_filtees, lockstate); 2548 obj->needed_aux_filtees = NULL; 2549 obj->filtees_loaded = false; 2550 } 2551 2552 static void 2553 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2554 RtldLockState *lockstate) 2555 { 2556 2557 for (; needed != NULL; needed = needed->next) { 2558 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2559 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2560 RTLD_LOCAL, lockstate); 2561 } 2562 } 2563 2564 static void 2565 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2566 { 2567 2568 lock_restart_for_upgrade(lockstate); 2569 if (!obj->filtees_loaded) { 2570 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2571 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2572 obj->filtees_loaded = true; 2573 } 2574 } 2575 2576 static int 2577 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2578 { 2579 Obj_Entry *obj1; 2580 2581 for (; needed != NULL; needed = needed->next) { 2582 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2583 flags & ~RTLD_LO_NOLOAD); 2584 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2585 return (-1); 2586 } 2587 return (0); 2588 } 2589 2590 /* 2591 * Given a shared object, traverse its list of needed objects, and load 2592 * each of them. Returns 0 on success. Generates an error message and 2593 * returns -1 on failure. 2594 */ 2595 static int 2596 load_needed_objects(Obj_Entry *first, int flags) 2597 { 2598 Obj_Entry *obj; 2599 2600 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2601 if (obj->marker) 2602 continue; 2603 if (process_needed(obj, obj->needed, flags) == -1) 2604 return (-1); 2605 } 2606 return (0); 2607 } 2608 2609 static int 2610 load_preload_objects(const char *penv, bool isfd) 2611 { 2612 Obj_Entry *obj; 2613 const char *name; 2614 size_t len; 2615 char savech, *p, *psave; 2616 int fd; 2617 static const char delim[] = " \t:;"; 2618 2619 if (penv == NULL) 2620 return (0); 2621 2622 p = psave = xstrdup(penv); 2623 p += strspn(p, delim); 2624 while (*p != '\0') { 2625 len = strcspn(p, delim); 2626 2627 savech = p[len]; 2628 p[len] = '\0'; 2629 if (isfd) { 2630 name = NULL; 2631 fd = parse_integer(p); 2632 if (fd == -1) { 2633 free(psave); 2634 return (-1); 2635 } 2636 } else { 2637 name = p; 2638 fd = -1; 2639 } 2640 2641 obj = load_object(name, fd, NULL, 0); 2642 if (obj == NULL) { 2643 free(psave); 2644 return (-1); /* XXX - cleanup */ 2645 } 2646 obj->z_interpose = true; 2647 p[len] = savech; 2648 p += len; 2649 p += strspn(p, delim); 2650 } 2651 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2652 2653 free(psave); 2654 return (0); 2655 } 2656 2657 static const char * 2658 printable_path(const char *path) 2659 { 2660 2661 return (path == NULL ? "<unknown>" : path); 2662 } 2663 2664 /* 2665 * Load a shared object into memory, if it is not already loaded. The 2666 * object may be specified by name or by user-supplied file descriptor 2667 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2668 * duplicate is. 2669 * 2670 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2671 * on failure. 2672 */ 2673 static Obj_Entry * 2674 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2675 { 2676 Obj_Entry *obj; 2677 int fd; 2678 struct stat sb; 2679 char *path; 2680 2681 fd = -1; 2682 if (name != NULL) { 2683 TAILQ_FOREACH(obj, &obj_list, next) { 2684 if (obj->marker || obj->doomed) 2685 continue; 2686 if (object_match_name(obj, name)) 2687 return (obj); 2688 } 2689 2690 path = find_library(name, refobj, &fd); 2691 if (path == NULL) 2692 return (NULL); 2693 } else 2694 path = NULL; 2695 2696 if (fd >= 0) { 2697 /* 2698 * search_library_pathfds() opens a fresh file descriptor for the 2699 * library, so there is no need to dup(). 2700 */ 2701 } else if (fd_u == -1) { 2702 /* 2703 * If we didn't find a match by pathname, or the name is not 2704 * supplied, open the file and check again by device and inode. 2705 * This avoids false mismatches caused by multiple links or ".." 2706 * in pathnames. 2707 * 2708 * To avoid a race, we open the file and use fstat() rather than 2709 * using stat(). 2710 */ 2711 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2712 _rtld_error("Cannot open \"%s\"", path); 2713 free(path); 2714 return (NULL); 2715 } 2716 } else { 2717 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2718 if (fd == -1) { 2719 _rtld_error("Cannot dup fd"); 2720 free(path); 2721 return (NULL); 2722 } 2723 } 2724 if (fstat(fd, &sb) == -1) { 2725 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2726 close(fd); 2727 free(path); 2728 return (NULL); 2729 } 2730 TAILQ_FOREACH(obj, &obj_list, next) { 2731 if (obj->marker || obj->doomed) 2732 continue; 2733 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2734 break; 2735 } 2736 if (obj != NULL && name != NULL) { 2737 object_add_name(obj, name); 2738 free(path); 2739 close(fd); 2740 return (obj); 2741 } 2742 if (flags & RTLD_LO_NOLOAD) { 2743 free(path); 2744 close(fd); 2745 return (NULL); 2746 } 2747 2748 /* First use of this object, so we must map it in */ 2749 obj = do_load_object(fd, name, path, &sb, flags); 2750 if (obj == NULL) 2751 free(path); 2752 close(fd); 2753 2754 return (obj); 2755 } 2756 2757 static Obj_Entry * 2758 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2759 int flags) 2760 { 2761 Obj_Entry *obj; 2762 struct statfs fs; 2763 2764 /* 2765 * First, make sure that environment variables haven't been 2766 * used to circumvent the noexec flag on a filesystem. 2767 * We ignore fstatfs(2) failures, since fd might reference 2768 * not a file, e.g. shmfd. 2769 */ 2770 if (dangerous_ld_env && fstatfs(fd, &fs) == 0 && 2771 (fs.f_flags & MNT_NOEXEC) != 0) { 2772 _rtld_error("Cannot execute objects on %s", fs.f_mntonname); 2773 return (NULL); 2774 } 2775 2776 dbg("loading \"%s\"", printable_path(path)); 2777 obj = map_object(fd, printable_path(path), sbp); 2778 if (obj == NULL) 2779 return (NULL); 2780 2781 /* 2782 * If DT_SONAME is present in the object, digest_dynamic2 already 2783 * added it to the object names. 2784 */ 2785 if (name != NULL) 2786 object_add_name(obj, name); 2787 obj->path = path; 2788 if (!digest_dynamic(obj, 0)) 2789 goto errp; 2790 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2791 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2792 if (obj->z_pie && (flags & RTLD_LO_TRACE) == 0) { 2793 dbg("refusing to load PIE executable \"%s\"", obj->path); 2794 _rtld_error("Cannot load PIE binary %s as DSO", obj->path); 2795 goto errp; 2796 } 2797 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2798 RTLD_LO_DLOPEN) { 2799 dbg("refusing to load non-loadable \"%s\"", obj->path); 2800 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2801 goto errp; 2802 } 2803 2804 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2805 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2806 obj_count++; 2807 obj_loads++; 2808 linkmap_add(obj); /* for GDB & dlinfo() */ 2809 max_stack_flags |= obj->stack_flags; 2810 2811 dbg(" %p .. %p: %s", obj->mapbase, 2812 obj->mapbase + obj->mapsize - 1, obj->path); 2813 if (obj->textrel) 2814 dbg(" WARNING: %s has impure text", obj->path); 2815 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2816 obj->path); 2817 2818 return (obj); 2819 2820 errp: 2821 munmap(obj->mapbase, obj->mapsize); 2822 obj_free(obj); 2823 return (NULL); 2824 } 2825 2826 static int 2827 load_kpreload(const void *addr) 2828 { 2829 Obj_Entry *obj; 2830 const Elf_Ehdr *ehdr; 2831 const Elf_Phdr *phdr, *phlimit, *phdyn, *seg0, *segn; 2832 static const char kname[] = "[vdso]"; 2833 2834 ehdr = addr; 2835 if (!check_elf_headers(ehdr, "kpreload")) 2836 return (-1); 2837 obj = obj_new(); 2838 phdr = (const Elf_Phdr *)((const char *)addr + ehdr->e_phoff); 2839 obj->phdr = phdr; 2840 obj->phsize = ehdr->e_phnum * sizeof(*phdr); 2841 phlimit = phdr + ehdr->e_phnum; 2842 seg0 = segn = NULL; 2843 2844 for (; phdr < phlimit; phdr++) { 2845 switch (phdr->p_type) { 2846 case PT_DYNAMIC: 2847 phdyn = phdr; 2848 break; 2849 case PT_GNU_STACK: 2850 /* Absense of PT_GNU_STACK implies stack_flags == 0. */ 2851 obj->stack_flags = phdr->p_flags; 2852 break; 2853 case PT_LOAD: 2854 if (seg0 == NULL || seg0->p_vaddr > phdr->p_vaddr) 2855 seg0 = phdr; 2856 if (segn == NULL || segn->p_vaddr + segn->p_memsz < 2857 phdr->p_vaddr + phdr->p_memsz) 2858 segn = phdr; 2859 break; 2860 } 2861 } 2862 2863 obj->mapbase = __DECONST(caddr_t, addr); 2864 obj->mapsize = segn->p_vaddr + segn->p_memsz - (Elf_Addr)addr; 2865 obj->vaddrbase = 0; 2866 obj->relocbase = obj->mapbase; 2867 2868 object_add_name(obj, kname); 2869 obj->path = xstrdup(kname); 2870 obj->dynamic = (const Elf_Dyn *)(obj->relocbase + phdyn->p_vaddr); 2871 2872 if (!digest_dynamic(obj, 0)) { 2873 obj_free(obj); 2874 return (-1); 2875 } 2876 2877 /* 2878 * We assume that kernel-preloaded object does not need 2879 * relocation. It is currently written into read-only page, 2880 * handling relocations would mean we need to allocate at 2881 * least one additional page per AS. 2882 */ 2883 dbg("%s mapbase %p phdrs %p PT_LOAD phdr %p vaddr %p dynamic %p", 2884 obj->path, obj->mapbase, obj->phdr, seg0, 2885 obj->relocbase + seg0->p_vaddr, obj->dynamic); 2886 2887 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2888 obj_count++; 2889 obj_loads++; 2890 linkmap_add(obj); /* for GDB & dlinfo() */ 2891 max_stack_flags |= obj->stack_flags; 2892 2893 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, 0, 0, obj->path); 2894 return (0); 2895 } 2896 2897 Obj_Entry * 2898 obj_from_addr(const void *addr) 2899 { 2900 Obj_Entry *obj; 2901 2902 TAILQ_FOREACH(obj, &obj_list, next) { 2903 if (obj->marker) 2904 continue; 2905 if (addr < (void *) obj->mapbase) 2906 continue; 2907 if (addr < (void *)(obj->mapbase + obj->mapsize)) 2908 return obj; 2909 } 2910 return (NULL); 2911 } 2912 2913 static void 2914 preinit_main(void) 2915 { 2916 Elf_Addr *preinit_addr; 2917 int index; 2918 2919 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2920 if (preinit_addr == NULL) 2921 return; 2922 2923 for (index = 0; index < obj_main->preinit_array_num; index++) { 2924 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2925 dbg("calling preinit function for %s at %p", obj_main->path, 2926 (void *)preinit_addr[index]); 2927 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2928 0, 0, obj_main->path); 2929 call_init_pointer(obj_main, preinit_addr[index]); 2930 } 2931 } 2932 } 2933 2934 /* 2935 * Call the finalization functions for each of the objects in "list" 2936 * belonging to the DAG of "root" and referenced once. If NULL "root" 2937 * is specified, every finalization function will be called regardless 2938 * of the reference count and the list elements won't be freed. All of 2939 * the objects are expected to have non-NULL fini functions. 2940 */ 2941 static void 2942 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2943 { 2944 Objlist_Entry *elm; 2945 struct dlerror_save *saved_msg; 2946 Elf_Addr *fini_addr; 2947 int index; 2948 2949 assert(root == NULL || root->refcount == 1); 2950 2951 if (root != NULL) 2952 root->doomed = true; 2953 2954 /* 2955 * Preserve the current error message since a fini function might 2956 * call into the dynamic linker and overwrite it. 2957 */ 2958 saved_msg = errmsg_save(); 2959 do { 2960 STAILQ_FOREACH(elm, list, link) { 2961 if (root != NULL && (elm->obj->refcount != 1 || 2962 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2963 continue; 2964 /* Remove object from fini list to prevent recursive invocation. */ 2965 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2966 /* Ensure that new references cannot be acquired. */ 2967 elm->obj->doomed = true; 2968 2969 hold_object(elm->obj); 2970 lock_release(rtld_bind_lock, lockstate); 2971 /* 2972 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2973 * When this happens, DT_FINI_ARRAY is processed first. 2974 */ 2975 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2976 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2977 for (index = elm->obj->fini_array_num - 1; index >= 0; 2978 index--) { 2979 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2980 dbg("calling fini function for %s at %p", 2981 elm->obj->path, (void *)fini_addr[index]); 2982 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2983 (void *)fini_addr[index], 0, 0, elm->obj->path); 2984 call_initfini_pointer(elm->obj, fini_addr[index]); 2985 } 2986 } 2987 } 2988 if (elm->obj->fini != (Elf_Addr)NULL) { 2989 dbg("calling fini function for %s at %p", elm->obj->path, 2990 (void *)elm->obj->fini); 2991 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2992 0, 0, elm->obj->path); 2993 call_initfini_pointer(elm->obj, elm->obj->fini); 2994 } 2995 wlock_acquire(rtld_bind_lock, lockstate); 2996 unhold_object(elm->obj); 2997 /* No need to free anything if process is going down. */ 2998 if (root != NULL) 2999 free(elm); 3000 /* 3001 * We must restart the list traversal after every fini call 3002 * because a dlclose() call from the fini function or from 3003 * another thread might have modified the reference counts. 3004 */ 3005 break; 3006 } 3007 } while (elm != NULL); 3008 errmsg_restore(saved_msg); 3009 } 3010 3011 /* 3012 * Call the initialization functions for each of the objects in 3013 * "list". All of the objects are expected to have non-NULL init 3014 * functions. 3015 */ 3016 static void 3017 objlist_call_init(Objlist *list, RtldLockState *lockstate) 3018 { 3019 Objlist_Entry *elm; 3020 Obj_Entry *obj; 3021 struct dlerror_save *saved_msg; 3022 Elf_Addr *init_addr; 3023 void (*reg)(void (*)(void)); 3024 int index; 3025 3026 /* 3027 * Clean init_scanned flag so that objects can be rechecked and 3028 * possibly initialized earlier if any of vectors called below 3029 * cause the change by using dlopen. 3030 */ 3031 TAILQ_FOREACH(obj, &obj_list, next) { 3032 if (obj->marker) 3033 continue; 3034 obj->init_scanned = false; 3035 } 3036 3037 /* 3038 * Preserve the current error message since an init function might 3039 * call into the dynamic linker and overwrite it. 3040 */ 3041 saved_msg = errmsg_save(); 3042 STAILQ_FOREACH(elm, list, link) { 3043 if (elm->obj->init_done) /* Initialized early. */ 3044 continue; 3045 /* 3046 * Race: other thread might try to use this object before current 3047 * one completes the initialization. Not much can be done here 3048 * without better locking. 3049 */ 3050 elm->obj->init_done = true; 3051 hold_object(elm->obj); 3052 reg = NULL; 3053 if (elm->obj == obj_main && obj_main->crt_no_init) { 3054 reg = (void (*)(void (*)(void)))get_program_var_addr( 3055 "__libc_atexit", lockstate); 3056 } 3057 lock_release(rtld_bind_lock, lockstate); 3058 if (reg != NULL) { 3059 reg(rtld_exit); 3060 rtld_exit_ptr = rtld_nop_exit; 3061 } 3062 3063 /* 3064 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 3065 * When this happens, DT_INIT is processed first. 3066 */ 3067 if (elm->obj->init != (Elf_Addr)NULL) { 3068 dbg("calling init function for %s at %p", elm->obj->path, 3069 (void *)elm->obj->init); 3070 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 3071 0, 0, elm->obj->path); 3072 call_init_pointer(elm->obj, elm->obj->init); 3073 } 3074 init_addr = (Elf_Addr *)elm->obj->init_array; 3075 if (init_addr != NULL) { 3076 for (index = 0; index < elm->obj->init_array_num; index++) { 3077 if (init_addr[index] != 0 && init_addr[index] != 1) { 3078 dbg("calling init function for %s at %p", elm->obj->path, 3079 (void *)init_addr[index]); 3080 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 3081 (void *)init_addr[index], 0, 0, elm->obj->path); 3082 call_init_pointer(elm->obj, init_addr[index]); 3083 } 3084 } 3085 } 3086 wlock_acquire(rtld_bind_lock, lockstate); 3087 unhold_object(elm->obj); 3088 } 3089 errmsg_restore(saved_msg); 3090 } 3091 3092 static void 3093 objlist_clear(Objlist *list) 3094 { 3095 Objlist_Entry *elm; 3096 3097 while (!STAILQ_EMPTY(list)) { 3098 elm = STAILQ_FIRST(list); 3099 STAILQ_REMOVE_HEAD(list, link); 3100 free(elm); 3101 } 3102 } 3103 3104 static Objlist_Entry * 3105 objlist_find(Objlist *list, const Obj_Entry *obj) 3106 { 3107 Objlist_Entry *elm; 3108 3109 STAILQ_FOREACH(elm, list, link) 3110 if (elm->obj == obj) 3111 return elm; 3112 return (NULL); 3113 } 3114 3115 static void 3116 objlist_init(Objlist *list) 3117 { 3118 STAILQ_INIT(list); 3119 } 3120 3121 static void 3122 objlist_push_head(Objlist *list, Obj_Entry *obj) 3123 { 3124 Objlist_Entry *elm; 3125 3126 elm = NEW(Objlist_Entry); 3127 elm->obj = obj; 3128 STAILQ_INSERT_HEAD(list, elm, link); 3129 } 3130 3131 static void 3132 objlist_push_tail(Objlist *list, Obj_Entry *obj) 3133 { 3134 Objlist_Entry *elm; 3135 3136 elm = NEW(Objlist_Entry); 3137 elm->obj = obj; 3138 STAILQ_INSERT_TAIL(list, elm, link); 3139 } 3140 3141 static void 3142 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 3143 { 3144 Objlist_Entry *elm, *listelm; 3145 3146 STAILQ_FOREACH(listelm, list, link) { 3147 if (listelm->obj == listobj) 3148 break; 3149 } 3150 elm = NEW(Objlist_Entry); 3151 elm->obj = obj; 3152 if (listelm != NULL) 3153 STAILQ_INSERT_AFTER(list, listelm, elm, link); 3154 else 3155 STAILQ_INSERT_TAIL(list, elm, link); 3156 } 3157 3158 static void 3159 objlist_remove(Objlist *list, Obj_Entry *obj) 3160 { 3161 Objlist_Entry *elm; 3162 3163 if ((elm = objlist_find(list, obj)) != NULL) { 3164 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 3165 free(elm); 3166 } 3167 } 3168 3169 /* 3170 * Relocate dag rooted in the specified object. 3171 * Returns 0 on success, or -1 on failure. 3172 */ 3173 3174 static int 3175 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 3176 int flags, RtldLockState *lockstate) 3177 { 3178 Objlist_Entry *elm; 3179 int error; 3180 3181 error = 0; 3182 STAILQ_FOREACH(elm, &root->dagmembers, link) { 3183 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 3184 lockstate); 3185 if (error == -1) 3186 break; 3187 } 3188 return (error); 3189 } 3190 3191 /* 3192 * Prepare for, or clean after, relocating an object marked with 3193 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 3194 * segments are remapped read-write. After relocations are done, the 3195 * segment's permissions are returned back to the modes specified in 3196 * the phdrs. If any relocation happened, or always for wired 3197 * program, COW is triggered. 3198 */ 3199 static int 3200 reloc_textrel_prot(Obj_Entry *obj, bool before) 3201 { 3202 const Elf_Phdr *ph; 3203 void *base; 3204 size_t l, sz; 3205 int prot; 3206 3207 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 3208 l--, ph++) { 3209 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 3210 continue; 3211 base = obj->relocbase + trunc_page(ph->p_vaddr); 3212 sz = round_page(ph->p_vaddr + ph->p_filesz) - 3213 trunc_page(ph->p_vaddr); 3214 prot = before ? (PROT_READ | PROT_WRITE) : 3215 convert_prot(ph->p_flags); 3216 if (mprotect(base, sz, prot) == -1) { 3217 _rtld_error("%s: Cannot write-%sable text segment: %s", 3218 obj->path, before ? "en" : "dis", 3219 rtld_strerror(errno)); 3220 return (-1); 3221 } 3222 } 3223 return (0); 3224 } 3225 3226 /* Process RELR relative relocations. */ 3227 static void 3228 reloc_relr(Obj_Entry *obj) 3229 { 3230 const Elf_Relr *relr, *relrlim; 3231 Elf_Addr *where; 3232 3233 relrlim = (const Elf_Relr *)((const char *)obj->relr + obj->relrsize); 3234 for (relr = obj->relr; relr < relrlim; relr++) { 3235 Elf_Relr entry = *relr; 3236 3237 if ((entry & 1) == 0) { 3238 where = (Elf_Addr *)(obj->relocbase + entry); 3239 *where++ += (Elf_Addr)obj->relocbase; 3240 } else { 3241 for (long i = 0; (entry >>= 1) != 0; i++) 3242 if ((entry & 1) != 0) 3243 where[i] += (Elf_Addr)obj->relocbase; 3244 where += CHAR_BIT * sizeof(Elf_Relr) - 1; 3245 } 3246 } 3247 } 3248 3249 /* 3250 * Relocate single object. 3251 * Returns 0 on success, or -1 on failure. 3252 */ 3253 static int 3254 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 3255 int flags, RtldLockState *lockstate) 3256 { 3257 3258 if (obj->relocated) 3259 return (0); 3260 obj->relocated = true; 3261 if (obj != rtldobj) 3262 dbg("relocating \"%s\"", obj->path); 3263 3264 if (obj->symtab == NULL || obj->strtab == NULL || 3265 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) 3266 dbg("object %s has no run-time symbol table", obj->path); 3267 3268 /* There are relocations to the write-protected text segment. */ 3269 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 3270 return (-1); 3271 3272 /* Process the non-PLT non-IFUNC relocations. */ 3273 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 3274 return (-1); 3275 reloc_relr(obj); 3276 3277 /* Re-protected the text segment. */ 3278 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 3279 return (-1); 3280 3281 /* Set the special PLT or GOT entries. */ 3282 init_pltgot(obj); 3283 3284 /* Process the PLT relocations. */ 3285 if (reloc_plt(obj, flags, lockstate) == -1) 3286 return (-1); 3287 /* Relocate the jump slots if we are doing immediate binding. */ 3288 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags, 3289 lockstate) == -1) 3290 return (-1); 3291 3292 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 3293 return (-1); 3294 3295 /* 3296 * Set up the magic number and version in the Obj_Entry. These 3297 * were checked in the crt1.o from the original ElfKit, so we 3298 * set them for backward compatibility. 3299 */ 3300 obj->magic = RTLD_MAGIC; 3301 obj->version = RTLD_VERSION; 3302 3303 return (0); 3304 } 3305 3306 /* 3307 * Relocate newly-loaded shared objects. The argument is a pointer to 3308 * the Obj_Entry for the first such object. All objects from the first 3309 * to the end of the list of objects are relocated. Returns 0 on success, 3310 * or -1 on failure. 3311 */ 3312 static int 3313 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 3314 int flags, RtldLockState *lockstate) 3315 { 3316 Obj_Entry *obj; 3317 int error; 3318 3319 for (error = 0, obj = first; obj != NULL; 3320 obj = TAILQ_NEXT(obj, next)) { 3321 if (obj->marker) 3322 continue; 3323 error = relocate_object(obj, bind_now, rtldobj, flags, 3324 lockstate); 3325 if (error == -1) 3326 break; 3327 } 3328 return (error); 3329 } 3330 3331 /* 3332 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 3333 * referencing STT_GNU_IFUNC symbols is postponed till the other 3334 * relocations are done. The indirect functions specified as 3335 * ifunc are allowed to call other symbols, so we need to have 3336 * objects relocated before asking for resolution from indirects. 3337 * 3338 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 3339 * instead of the usual lazy handling of PLT slots. It is 3340 * consistent with how GNU does it. 3341 */ 3342 static int 3343 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 3344 RtldLockState *lockstate) 3345 { 3346 3347 if (obj->ifuncs_resolved) 3348 return (0); 3349 obj->ifuncs_resolved = true; 3350 if (!obj->irelative && !obj->irelative_nonplt && 3351 !((obj->bind_now || bind_now) && obj->gnu_ifunc) && 3352 !obj->non_plt_gnu_ifunc) 3353 return (0); 3354 if (obj_disable_relro(obj) == -1 || 3355 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) || 3356 (obj->irelative_nonplt && reloc_iresolve_nonplt(obj, 3357 lockstate) == -1) || 3358 ((obj->bind_now || bind_now) && obj->gnu_ifunc && 3359 reloc_gnu_ifunc(obj, flags, lockstate) == -1) || 3360 (obj->non_plt_gnu_ifunc && reloc_non_plt(obj, &obj_rtld, 3361 flags | SYMLOOK_IFUNC, lockstate) == -1) || 3362 obj_enforce_relro(obj) == -1) 3363 return (-1); 3364 return (0); 3365 } 3366 3367 static int 3368 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 3369 RtldLockState *lockstate) 3370 { 3371 Objlist_Entry *elm; 3372 Obj_Entry *obj; 3373 3374 STAILQ_FOREACH(elm, list, link) { 3375 obj = elm->obj; 3376 if (obj->marker) 3377 continue; 3378 if (resolve_object_ifunc(obj, bind_now, flags, 3379 lockstate) == -1) 3380 return (-1); 3381 } 3382 return (0); 3383 } 3384 3385 /* 3386 * Cleanup procedure. It will be called (by the atexit mechanism) just 3387 * before the process exits. 3388 */ 3389 static void 3390 rtld_exit(void) 3391 { 3392 RtldLockState lockstate; 3393 3394 wlock_acquire(rtld_bind_lock, &lockstate); 3395 dbg("rtld_exit()"); 3396 objlist_call_fini(&list_fini, NULL, &lockstate); 3397 /* No need to remove the items from the list, since we are exiting. */ 3398 if (!libmap_disable) 3399 lm_fini(); 3400 lock_release(rtld_bind_lock, &lockstate); 3401 } 3402 3403 static void 3404 rtld_nop_exit(void) 3405 { 3406 } 3407 3408 /* 3409 * Iterate over a search path, translate each element, and invoke the 3410 * callback on the result. 3411 */ 3412 static void * 3413 path_enumerate(const char *path, path_enum_proc callback, 3414 const char *refobj_path, void *arg) 3415 { 3416 const char *trans; 3417 if (path == NULL) 3418 return (NULL); 3419 3420 path += strspn(path, ":;"); 3421 while (*path != '\0') { 3422 size_t len; 3423 char *res; 3424 3425 len = strcspn(path, ":;"); 3426 trans = lm_findn(refobj_path, path, len); 3427 if (trans) 3428 res = callback(trans, strlen(trans), arg); 3429 else 3430 res = callback(path, len, arg); 3431 3432 if (res != NULL) 3433 return (res); 3434 3435 path += len; 3436 path += strspn(path, ":;"); 3437 } 3438 3439 return (NULL); 3440 } 3441 3442 struct try_library_args { 3443 const char *name; 3444 size_t namelen; 3445 char *buffer; 3446 size_t buflen; 3447 int fd; 3448 }; 3449 3450 static void * 3451 try_library_path(const char *dir, size_t dirlen, void *param) 3452 { 3453 struct try_library_args *arg; 3454 int fd; 3455 3456 arg = param; 3457 if (*dir == '/' || trust) { 3458 char *pathname; 3459 3460 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3461 return (NULL); 3462 3463 pathname = arg->buffer; 3464 strncpy(pathname, dir, dirlen); 3465 pathname[dirlen] = '/'; 3466 strcpy(pathname + dirlen + 1, arg->name); 3467 3468 dbg(" Trying \"%s\"", pathname); 3469 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY); 3470 if (fd >= 0) { 3471 dbg(" Opened \"%s\", fd %d", pathname, fd); 3472 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3473 strcpy(pathname, arg->buffer); 3474 arg->fd = fd; 3475 return (pathname); 3476 } else { 3477 dbg(" Failed to open \"%s\": %s", 3478 pathname, rtld_strerror(errno)); 3479 } 3480 } 3481 return (NULL); 3482 } 3483 3484 static char * 3485 search_library_path(const char *name, const char *path, 3486 const char *refobj_path, int *fdp) 3487 { 3488 char *p; 3489 struct try_library_args arg; 3490 3491 if (path == NULL) 3492 return (NULL); 3493 3494 arg.name = name; 3495 arg.namelen = strlen(name); 3496 arg.buffer = xmalloc(PATH_MAX); 3497 arg.buflen = PATH_MAX; 3498 arg.fd = -1; 3499 3500 p = path_enumerate(path, try_library_path, refobj_path, &arg); 3501 *fdp = arg.fd; 3502 3503 free(arg.buffer); 3504 3505 return (p); 3506 } 3507 3508 3509 /* 3510 * Finds the library with the given name using the directory descriptors 3511 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3512 * 3513 * Returns a freshly-opened close-on-exec file descriptor for the library, 3514 * or -1 if the library cannot be found. 3515 */ 3516 static char * 3517 search_library_pathfds(const char *name, const char *path, int *fdp) 3518 { 3519 char *envcopy, *fdstr, *found, *last_token; 3520 size_t len; 3521 int dirfd, fd; 3522 3523 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3524 3525 /* Don't load from user-specified libdirs into setuid binaries. */ 3526 if (!trust) 3527 return (NULL); 3528 3529 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3530 if (path == NULL) 3531 return (NULL); 3532 3533 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3534 if (name[0] == '/') { 3535 dbg("Absolute path (%s) passed to %s", name, __func__); 3536 return (NULL); 3537 } 3538 3539 /* 3540 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3541 * copy of the path, as strtok_r rewrites separator tokens 3542 * with '\0'. 3543 */ 3544 found = NULL; 3545 envcopy = xstrdup(path); 3546 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3547 fdstr = strtok_r(NULL, ":", &last_token)) { 3548 dirfd = parse_integer(fdstr); 3549 if (dirfd < 0) { 3550 _rtld_error("failed to parse directory FD: '%s'", 3551 fdstr); 3552 break; 3553 } 3554 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3555 if (fd >= 0) { 3556 *fdp = fd; 3557 len = strlen(fdstr) + strlen(name) + 3; 3558 found = xmalloc(len); 3559 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3560 _rtld_error("error generating '%d/%s'", 3561 dirfd, name); 3562 rtld_die(); 3563 } 3564 dbg("open('%s') => %d", found, fd); 3565 break; 3566 } 3567 } 3568 free(envcopy); 3569 3570 return (found); 3571 } 3572 3573 3574 int 3575 dlclose(void *handle) 3576 { 3577 RtldLockState lockstate; 3578 int error; 3579 3580 wlock_acquire(rtld_bind_lock, &lockstate); 3581 error = dlclose_locked(handle, &lockstate); 3582 lock_release(rtld_bind_lock, &lockstate); 3583 return (error); 3584 } 3585 3586 static int 3587 dlclose_locked(void *handle, RtldLockState *lockstate) 3588 { 3589 Obj_Entry *root; 3590 3591 root = dlcheck(handle); 3592 if (root == NULL) 3593 return (-1); 3594 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3595 root->path); 3596 3597 /* Unreference the object and its dependencies. */ 3598 root->dl_refcount--; 3599 3600 if (root->refcount == 1) { 3601 /* 3602 * The object will be no longer referenced, so we must unload it. 3603 * First, call the fini functions. 3604 */ 3605 objlist_call_fini(&list_fini, root, lockstate); 3606 3607 unref_dag(root); 3608 3609 /* Finish cleaning up the newly-unreferenced objects. */ 3610 GDB_STATE(RT_DELETE,&root->linkmap); 3611 unload_object(root, lockstate); 3612 GDB_STATE(RT_CONSISTENT,NULL); 3613 } else 3614 unref_dag(root); 3615 3616 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3617 return (0); 3618 } 3619 3620 char * 3621 dlerror(void) 3622 { 3623 if (*(lockinfo.dlerror_seen()) != 0) 3624 return (NULL); 3625 *lockinfo.dlerror_seen() = 1; 3626 return (lockinfo.dlerror_loc()); 3627 } 3628 3629 /* 3630 * This function is deprecated and has no effect. 3631 */ 3632 void 3633 dllockinit(void *context, 3634 void *(*_lock_create)(void *context) __unused, 3635 void (*_rlock_acquire)(void *lock) __unused, 3636 void (*_wlock_acquire)(void *lock) __unused, 3637 void (*_lock_release)(void *lock) __unused, 3638 void (*_lock_destroy)(void *lock) __unused, 3639 void (*context_destroy)(void *context)) 3640 { 3641 static void *cur_context; 3642 static void (*cur_context_destroy)(void *); 3643 3644 /* Just destroy the context from the previous call, if necessary. */ 3645 if (cur_context_destroy != NULL) 3646 cur_context_destroy(cur_context); 3647 cur_context = context; 3648 cur_context_destroy = context_destroy; 3649 } 3650 3651 void * 3652 dlopen(const char *name, int mode) 3653 { 3654 3655 return (rtld_dlopen(name, -1, mode)); 3656 } 3657 3658 void * 3659 fdlopen(int fd, int mode) 3660 { 3661 3662 return (rtld_dlopen(NULL, fd, mode)); 3663 } 3664 3665 static void * 3666 rtld_dlopen(const char *name, int fd, int mode) 3667 { 3668 RtldLockState lockstate; 3669 int lo_flags; 3670 3671 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3672 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3673 if (ld_tracing != NULL) { 3674 rlock_acquire(rtld_bind_lock, &lockstate); 3675 if (sigsetjmp(lockstate.env, 0) != 0) 3676 lock_upgrade(rtld_bind_lock, &lockstate); 3677 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate)); 3678 lock_release(rtld_bind_lock, &lockstate); 3679 } 3680 lo_flags = RTLD_LO_DLOPEN; 3681 if (mode & RTLD_NODELETE) 3682 lo_flags |= RTLD_LO_NODELETE; 3683 if (mode & RTLD_NOLOAD) 3684 lo_flags |= RTLD_LO_NOLOAD; 3685 if (mode & RTLD_DEEPBIND) 3686 lo_flags |= RTLD_LO_DEEPBIND; 3687 if (ld_tracing != NULL) 3688 lo_flags |= RTLD_LO_TRACE | RTLD_LO_IGNSTLS; 3689 3690 return (dlopen_object(name, fd, obj_main, lo_flags, 3691 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3692 } 3693 3694 static void 3695 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3696 { 3697 3698 obj->dl_refcount--; 3699 unref_dag(obj); 3700 if (obj->refcount == 0) 3701 unload_object(obj, lockstate); 3702 } 3703 3704 static Obj_Entry * 3705 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3706 int mode, RtldLockState *lockstate) 3707 { 3708 Obj_Entry *old_obj_tail; 3709 Obj_Entry *obj; 3710 Objlist initlist; 3711 RtldLockState mlockstate; 3712 int result; 3713 3714 dbg("dlopen_object name \"%s\" fd %d refobj \"%s\" lo_flags %#x mode %#x", 3715 name != NULL ? name : "<null>", fd, refobj == NULL ? "<null>" : 3716 refobj->path, lo_flags, mode); 3717 objlist_init(&initlist); 3718 3719 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3720 wlock_acquire(rtld_bind_lock, &mlockstate); 3721 lockstate = &mlockstate; 3722 } 3723 GDB_STATE(RT_ADD,NULL); 3724 3725 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3726 obj = NULL; 3727 if (name == NULL && fd == -1) { 3728 obj = obj_main; 3729 obj->refcount++; 3730 } else { 3731 obj = load_object(name, fd, refobj, lo_flags); 3732 } 3733 3734 if (obj) { 3735 obj->dl_refcount++; 3736 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3737 objlist_push_tail(&list_global, obj); 3738 if (globallist_next(old_obj_tail) != NULL) { 3739 /* We loaded something new. */ 3740 assert(globallist_next(old_obj_tail) == obj); 3741 if ((lo_flags & RTLD_LO_DEEPBIND) != 0) 3742 obj->symbolic = true; 3743 result = 0; 3744 if ((lo_flags & (RTLD_LO_EARLY | RTLD_LO_IGNSTLS)) == 0 && 3745 obj->static_tls && !allocate_tls_offset(obj)) { 3746 _rtld_error("%s: No space available " 3747 "for static Thread Local Storage", obj->path); 3748 result = -1; 3749 } 3750 if (result != -1) 3751 result = load_needed_objects(obj, lo_flags & (RTLD_LO_DLOPEN | 3752 RTLD_LO_EARLY | RTLD_LO_IGNSTLS | RTLD_LO_TRACE)); 3753 init_dag(obj); 3754 ref_dag(obj); 3755 if (result != -1) 3756 result = rtld_verify_versions(&obj->dagmembers); 3757 if (result != -1 && ld_tracing) 3758 goto trace; 3759 if (result == -1 || relocate_object_dag(obj, 3760 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3761 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3762 lockstate) == -1) { 3763 dlopen_cleanup(obj, lockstate); 3764 obj = NULL; 3765 } else if (lo_flags & RTLD_LO_EARLY) { 3766 /* 3767 * Do not call the init functions for early loaded 3768 * filtees. The image is still not initialized enough 3769 * for them to work. 3770 * 3771 * Our object is found by the global object list and 3772 * will be ordered among all init calls done right 3773 * before transferring control to main. 3774 */ 3775 } else { 3776 /* Make list of init functions to call. */ 3777 initlist_add_objects(obj, obj, &initlist); 3778 } 3779 /* 3780 * Process all no_delete or global objects here, given 3781 * them own DAGs to prevent their dependencies from being 3782 * unloaded. This has to be done after we have loaded all 3783 * of the dependencies, so that we do not miss any. 3784 */ 3785 if (obj != NULL) 3786 process_z(obj); 3787 } else { 3788 /* 3789 * Bump the reference counts for objects on this DAG. If 3790 * this is the first dlopen() call for the object that was 3791 * already loaded as a dependency, initialize the dag 3792 * starting at it. 3793 */ 3794 init_dag(obj); 3795 ref_dag(obj); 3796 3797 if ((lo_flags & RTLD_LO_TRACE) != 0) 3798 goto trace; 3799 } 3800 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3801 obj->z_nodelete) && !obj->ref_nodel) { 3802 dbg("obj %s nodelete", obj->path); 3803 ref_dag(obj); 3804 obj->z_nodelete = obj->ref_nodel = true; 3805 } 3806 } 3807 3808 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3809 name); 3810 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3811 3812 if ((lo_flags & RTLD_LO_EARLY) == 0) { 3813 map_stacks_exec(lockstate); 3814 if (obj != NULL) 3815 distribute_static_tls(&initlist, lockstate); 3816 } 3817 3818 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3819 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3820 lockstate) == -1) { 3821 objlist_clear(&initlist); 3822 dlopen_cleanup(obj, lockstate); 3823 if (lockstate == &mlockstate) 3824 lock_release(rtld_bind_lock, lockstate); 3825 return (NULL); 3826 } 3827 3828 if (!(lo_flags & RTLD_LO_EARLY)) { 3829 /* Call the init functions. */ 3830 objlist_call_init(&initlist, lockstate); 3831 } 3832 objlist_clear(&initlist); 3833 if (lockstate == &mlockstate) 3834 lock_release(rtld_bind_lock, lockstate); 3835 return (obj); 3836 trace: 3837 trace_loaded_objects(obj, false); 3838 if (lockstate == &mlockstate) 3839 lock_release(rtld_bind_lock, lockstate); 3840 exit(0); 3841 } 3842 3843 static void * 3844 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3845 int flags) 3846 { 3847 DoneList donelist; 3848 const Obj_Entry *obj, *defobj; 3849 const Elf_Sym *def; 3850 SymLook req; 3851 RtldLockState lockstate; 3852 tls_index ti; 3853 void *sym; 3854 int res; 3855 3856 def = NULL; 3857 defobj = NULL; 3858 symlook_init(&req, name); 3859 req.ventry = ve; 3860 req.flags = flags | SYMLOOK_IN_PLT; 3861 req.lockstate = &lockstate; 3862 3863 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3864 rlock_acquire(rtld_bind_lock, &lockstate); 3865 if (sigsetjmp(lockstate.env, 0) != 0) 3866 lock_upgrade(rtld_bind_lock, &lockstate); 3867 if (handle == NULL || handle == RTLD_NEXT || 3868 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3869 3870 if ((obj = obj_from_addr(retaddr)) == NULL) { 3871 _rtld_error("Cannot determine caller's shared object"); 3872 lock_release(rtld_bind_lock, &lockstate); 3873 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3874 return (NULL); 3875 } 3876 if (handle == NULL) { /* Just the caller's shared object. */ 3877 res = symlook_obj(&req, obj); 3878 if (res == 0) { 3879 def = req.sym_out; 3880 defobj = req.defobj_out; 3881 } 3882 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3883 handle == RTLD_SELF) { /* ... caller included */ 3884 if (handle == RTLD_NEXT) 3885 obj = globallist_next(obj); 3886 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3887 if (obj->marker) 3888 continue; 3889 res = symlook_obj(&req, obj); 3890 if (res == 0) { 3891 if (def == NULL || (ld_dynamic_weak && 3892 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK)) { 3893 def = req.sym_out; 3894 defobj = req.defobj_out; 3895 if (!ld_dynamic_weak || 3896 ELF_ST_BIND(def->st_info) != STB_WEAK) 3897 break; 3898 } 3899 } 3900 } 3901 /* 3902 * Search the dynamic linker itself, and possibly resolve the 3903 * symbol from there. This is how the application links to 3904 * dynamic linker services such as dlopen. 3905 * Note that we ignore ld_dynamic_weak == false case, 3906 * always overriding weak symbols by rtld definitions. 3907 */ 3908 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3909 res = symlook_obj(&req, &obj_rtld); 3910 if (res == 0) { 3911 def = req.sym_out; 3912 defobj = req.defobj_out; 3913 } 3914 } 3915 } else { 3916 assert(handle == RTLD_DEFAULT); 3917 res = symlook_default(&req, obj); 3918 if (res == 0) { 3919 defobj = req.defobj_out; 3920 def = req.sym_out; 3921 } 3922 } 3923 } else { 3924 if ((obj = dlcheck(handle)) == NULL) { 3925 lock_release(rtld_bind_lock, &lockstate); 3926 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3927 return (NULL); 3928 } 3929 3930 donelist_init(&donelist); 3931 if (obj->mainprog) { 3932 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3933 res = symlook_global(&req, &donelist); 3934 if (res == 0) { 3935 def = req.sym_out; 3936 defobj = req.defobj_out; 3937 } 3938 /* 3939 * Search the dynamic linker itself, and possibly resolve the 3940 * symbol from there. This is how the application links to 3941 * dynamic linker services such as dlopen. 3942 */ 3943 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3944 res = symlook_obj(&req, &obj_rtld); 3945 if (res == 0) { 3946 def = req.sym_out; 3947 defobj = req.defobj_out; 3948 } 3949 } 3950 } 3951 else { 3952 /* Search the whole DAG rooted at the given object. */ 3953 res = symlook_list(&req, &obj->dagmembers, &donelist); 3954 if (res == 0) { 3955 def = req.sym_out; 3956 defobj = req.defobj_out; 3957 } 3958 } 3959 } 3960 3961 if (def != NULL) { 3962 lock_release(rtld_bind_lock, &lockstate); 3963 3964 /* 3965 * The value required by the caller is derived from the value 3966 * of the symbol. this is simply the relocated value of the 3967 * symbol. 3968 */ 3969 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3970 sym = make_function_pointer(def, defobj); 3971 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3972 sym = rtld_resolve_ifunc(defobj, def); 3973 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3974 ti.ti_module = defobj->tlsindex; 3975 ti.ti_offset = def->st_value; 3976 sym = __tls_get_addr(&ti); 3977 } else 3978 sym = defobj->relocbase + def->st_value; 3979 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3980 return (sym); 3981 } 3982 3983 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 3984 ve != NULL ? ve->name : ""); 3985 lock_release(rtld_bind_lock, &lockstate); 3986 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3987 return (NULL); 3988 } 3989 3990 void * 3991 dlsym(void *handle, const char *name) 3992 { 3993 return (do_dlsym(handle, name, __builtin_return_address(0), NULL, 3994 SYMLOOK_DLSYM)); 3995 } 3996 3997 dlfunc_t 3998 dlfunc(void *handle, const char *name) 3999 { 4000 union { 4001 void *d; 4002 dlfunc_t f; 4003 } rv; 4004 4005 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 4006 SYMLOOK_DLSYM); 4007 return (rv.f); 4008 } 4009 4010 void * 4011 dlvsym(void *handle, const char *name, const char *version) 4012 { 4013 Ver_Entry ventry; 4014 4015 ventry.name = version; 4016 ventry.file = NULL; 4017 ventry.hash = elf_hash(version); 4018 ventry.flags= 0; 4019 return (do_dlsym(handle, name, __builtin_return_address(0), &ventry, 4020 SYMLOOK_DLSYM)); 4021 } 4022 4023 int 4024 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 4025 { 4026 const Obj_Entry *obj; 4027 RtldLockState lockstate; 4028 4029 rlock_acquire(rtld_bind_lock, &lockstate); 4030 obj = obj_from_addr(addr); 4031 if (obj == NULL) { 4032 _rtld_error("No shared object contains address"); 4033 lock_release(rtld_bind_lock, &lockstate); 4034 return (0); 4035 } 4036 rtld_fill_dl_phdr_info(obj, phdr_info); 4037 lock_release(rtld_bind_lock, &lockstate); 4038 return (1); 4039 } 4040 4041 int 4042 dladdr(const void *addr, Dl_info *info) 4043 { 4044 const Obj_Entry *obj; 4045 const Elf_Sym *def; 4046 void *symbol_addr; 4047 unsigned long symoffset; 4048 RtldLockState lockstate; 4049 4050 rlock_acquire(rtld_bind_lock, &lockstate); 4051 obj = obj_from_addr(addr); 4052 if (obj == NULL) { 4053 _rtld_error("No shared object contains address"); 4054 lock_release(rtld_bind_lock, &lockstate); 4055 return (0); 4056 } 4057 info->dli_fname = obj->path; 4058 info->dli_fbase = obj->mapbase; 4059 info->dli_saddr = (void *)0; 4060 info->dli_sname = NULL; 4061 4062 /* 4063 * Walk the symbol list looking for the symbol whose address is 4064 * closest to the address sent in. 4065 */ 4066 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 4067 def = obj->symtab + symoffset; 4068 4069 /* 4070 * For skip the symbol if st_shndx is either SHN_UNDEF or 4071 * SHN_COMMON. 4072 */ 4073 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 4074 continue; 4075 4076 /* 4077 * If the symbol is greater than the specified address, or if it 4078 * is further away from addr than the current nearest symbol, 4079 * then reject it. 4080 */ 4081 symbol_addr = obj->relocbase + def->st_value; 4082 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 4083 continue; 4084 4085 /* Update our idea of the nearest symbol. */ 4086 info->dli_sname = obj->strtab + def->st_name; 4087 info->dli_saddr = symbol_addr; 4088 4089 /* Exact match? */ 4090 if (info->dli_saddr == addr) 4091 break; 4092 } 4093 lock_release(rtld_bind_lock, &lockstate); 4094 return (1); 4095 } 4096 4097 int 4098 dlinfo(void *handle, int request, void *p) 4099 { 4100 const Obj_Entry *obj; 4101 RtldLockState lockstate; 4102 int error; 4103 4104 rlock_acquire(rtld_bind_lock, &lockstate); 4105 4106 if (handle == NULL || handle == RTLD_SELF) { 4107 void *retaddr; 4108 4109 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 4110 if ((obj = obj_from_addr(retaddr)) == NULL) 4111 _rtld_error("Cannot determine caller's shared object"); 4112 } else 4113 obj = dlcheck(handle); 4114 4115 if (obj == NULL) { 4116 lock_release(rtld_bind_lock, &lockstate); 4117 return (-1); 4118 } 4119 4120 error = 0; 4121 switch (request) { 4122 case RTLD_DI_LINKMAP: 4123 *((struct link_map const **)p) = &obj->linkmap; 4124 break; 4125 case RTLD_DI_ORIGIN: 4126 error = rtld_dirname(obj->path, p); 4127 break; 4128 4129 case RTLD_DI_SERINFOSIZE: 4130 case RTLD_DI_SERINFO: 4131 error = do_search_info(obj, request, (struct dl_serinfo *)p); 4132 break; 4133 4134 default: 4135 _rtld_error("Invalid request %d passed to dlinfo()", request); 4136 error = -1; 4137 } 4138 4139 lock_release(rtld_bind_lock, &lockstate); 4140 4141 return (error); 4142 } 4143 4144 static void 4145 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 4146 { 4147 uintptr_t **dtvp; 4148 4149 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 4150 phdr_info->dlpi_name = obj->path; 4151 phdr_info->dlpi_phdr = obj->phdr; 4152 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 4153 phdr_info->dlpi_tls_modid = obj->tlsindex; 4154 dtvp = &_tcb_get()->tcb_dtv; 4155 phdr_info->dlpi_tls_data = (char *)tls_get_addr_slow(dtvp, 4156 obj->tlsindex, 0, true) + TLS_DTV_OFFSET; 4157 phdr_info->dlpi_adds = obj_loads; 4158 phdr_info->dlpi_subs = obj_loads - obj_count; 4159 } 4160 4161 int 4162 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 4163 { 4164 struct dl_phdr_info phdr_info; 4165 Obj_Entry *obj, marker; 4166 RtldLockState bind_lockstate, phdr_lockstate; 4167 int error; 4168 4169 init_marker(&marker); 4170 error = 0; 4171 4172 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 4173 wlock_acquire(rtld_bind_lock, &bind_lockstate); 4174 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 4175 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 4176 rtld_fill_dl_phdr_info(obj, &phdr_info); 4177 hold_object(obj); 4178 lock_release(rtld_bind_lock, &bind_lockstate); 4179 4180 error = callback(&phdr_info, sizeof phdr_info, param); 4181 4182 wlock_acquire(rtld_bind_lock, &bind_lockstate); 4183 unhold_object(obj); 4184 obj = globallist_next(&marker); 4185 TAILQ_REMOVE(&obj_list, &marker, next); 4186 if (error != 0) { 4187 lock_release(rtld_bind_lock, &bind_lockstate); 4188 lock_release(rtld_phdr_lock, &phdr_lockstate); 4189 return (error); 4190 } 4191 } 4192 4193 if (error == 0) { 4194 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 4195 lock_release(rtld_bind_lock, &bind_lockstate); 4196 error = callback(&phdr_info, sizeof(phdr_info), param); 4197 } 4198 lock_release(rtld_phdr_lock, &phdr_lockstate); 4199 return (error); 4200 } 4201 4202 static void * 4203 fill_search_info(const char *dir, size_t dirlen, void *param) 4204 { 4205 struct fill_search_info_args *arg; 4206 4207 arg = param; 4208 4209 if (arg->request == RTLD_DI_SERINFOSIZE) { 4210 arg->serinfo->dls_cnt ++; 4211 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 4212 } else { 4213 struct dl_serpath *s_entry; 4214 4215 s_entry = arg->serpath; 4216 s_entry->dls_name = arg->strspace; 4217 s_entry->dls_flags = arg->flags; 4218 4219 strncpy(arg->strspace, dir, dirlen); 4220 arg->strspace[dirlen] = '\0'; 4221 4222 arg->strspace += dirlen + 1; 4223 arg->serpath++; 4224 } 4225 4226 return (NULL); 4227 } 4228 4229 static int 4230 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 4231 { 4232 struct dl_serinfo _info; 4233 struct fill_search_info_args args; 4234 4235 args.request = RTLD_DI_SERINFOSIZE; 4236 args.serinfo = &_info; 4237 4238 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 4239 _info.dls_cnt = 0; 4240 4241 path_enumerate(obj->rpath, fill_search_info, NULL, &args); 4242 path_enumerate(ld_library_path, fill_search_info, NULL, &args); 4243 path_enumerate(obj->runpath, fill_search_info, NULL, &args); 4244 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args); 4245 if (!obj->z_nodeflib) 4246 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args); 4247 4248 4249 if (request == RTLD_DI_SERINFOSIZE) { 4250 info->dls_size = _info.dls_size; 4251 info->dls_cnt = _info.dls_cnt; 4252 return (0); 4253 } 4254 4255 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 4256 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 4257 return (-1); 4258 } 4259 4260 args.request = RTLD_DI_SERINFO; 4261 args.serinfo = info; 4262 args.serpath = &info->dls_serpath[0]; 4263 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 4264 4265 args.flags = LA_SER_RUNPATH; 4266 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL) 4267 return (-1); 4268 4269 args.flags = LA_SER_LIBPATH; 4270 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL) 4271 return (-1); 4272 4273 args.flags = LA_SER_RUNPATH; 4274 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL) 4275 return (-1); 4276 4277 args.flags = LA_SER_CONFIG; 4278 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args) 4279 != NULL) 4280 return (-1); 4281 4282 args.flags = LA_SER_DEFAULT; 4283 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path, 4284 fill_search_info, NULL, &args) != NULL) 4285 return (-1); 4286 return (0); 4287 } 4288 4289 static int 4290 rtld_dirname(const char *path, char *bname) 4291 { 4292 const char *endp; 4293 4294 /* Empty or NULL string gets treated as "." */ 4295 if (path == NULL || *path == '\0') { 4296 bname[0] = '.'; 4297 bname[1] = '\0'; 4298 return (0); 4299 } 4300 4301 /* Strip trailing slashes */ 4302 endp = path + strlen(path) - 1; 4303 while (endp > path && *endp == '/') 4304 endp--; 4305 4306 /* Find the start of the dir */ 4307 while (endp > path && *endp != '/') 4308 endp--; 4309 4310 /* Either the dir is "/" or there are no slashes */ 4311 if (endp == path) { 4312 bname[0] = *endp == '/' ? '/' : '.'; 4313 bname[1] = '\0'; 4314 return (0); 4315 } else { 4316 do { 4317 endp--; 4318 } while (endp > path && *endp == '/'); 4319 } 4320 4321 if (endp - path + 2 > PATH_MAX) 4322 { 4323 _rtld_error("Filename is too long: %s", path); 4324 return(-1); 4325 } 4326 4327 strncpy(bname, path, endp - path + 1); 4328 bname[endp - path + 1] = '\0'; 4329 return (0); 4330 } 4331 4332 static int 4333 rtld_dirname_abs(const char *path, char *base) 4334 { 4335 char *last; 4336 4337 if (realpath(path, base) == NULL) { 4338 _rtld_error("realpath \"%s\" failed (%s)", path, 4339 rtld_strerror(errno)); 4340 return (-1); 4341 } 4342 dbg("%s -> %s", path, base); 4343 last = strrchr(base, '/'); 4344 if (last == NULL) { 4345 _rtld_error("non-abs result from realpath \"%s\"", path); 4346 return (-1); 4347 } 4348 if (last != base) 4349 *last = '\0'; 4350 return (0); 4351 } 4352 4353 static void 4354 linkmap_add(Obj_Entry *obj) 4355 { 4356 struct link_map *l, *prev; 4357 4358 l = &obj->linkmap; 4359 l->l_name = obj->path; 4360 l->l_base = obj->mapbase; 4361 l->l_ld = obj->dynamic; 4362 l->l_addr = obj->relocbase; 4363 4364 if (r_debug.r_map == NULL) { 4365 r_debug.r_map = l; 4366 return; 4367 } 4368 4369 /* 4370 * Scan to the end of the list, but not past the entry for the 4371 * dynamic linker, which we want to keep at the very end. 4372 */ 4373 for (prev = r_debug.r_map; 4374 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 4375 prev = prev->l_next) 4376 ; 4377 4378 /* Link in the new entry. */ 4379 l->l_prev = prev; 4380 l->l_next = prev->l_next; 4381 if (l->l_next != NULL) 4382 l->l_next->l_prev = l; 4383 prev->l_next = l; 4384 } 4385 4386 static void 4387 linkmap_delete(Obj_Entry *obj) 4388 { 4389 struct link_map *l; 4390 4391 l = &obj->linkmap; 4392 if (l->l_prev == NULL) { 4393 if ((r_debug.r_map = l->l_next) != NULL) 4394 l->l_next->l_prev = NULL; 4395 return; 4396 } 4397 4398 if ((l->l_prev->l_next = l->l_next) != NULL) 4399 l->l_next->l_prev = l->l_prev; 4400 } 4401 4402 /* 4403 * Function for the debugger to set a breakpoint on to gain control. 4404 * 4405 * The two parameters allow the debugger to easily find and determine 4406 * what the runtime loader is doing and to whom it is doing it. 4407 * 4408 * When the loadhook trap is hit (r_debug_state, set at program 4409 * initialization), the arguments can be found on the stack: 4410 * 4411 * +8 struct link_map *m 4412 * +4 struct r_debug *rd 4413 * +0 RetAddr 4414 */ 4415 void 4416 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused) 4417 { 4418 /* 4419 * The following is a hack to force the compiler to emit calls to 4420 * this function, even when optimizing. If the function is empty, 4421 * the compiler is not obliged to emit any code for calls to it, 4422 * even when marked __noinline. However, gdb depends on those 4423 * calls being made. 4424 */ 4425 __compiler_membar(); 4426 } 4427 4428 /* 4429 * A function called after init routines have completed. This can be used to 4430 * break before a program's entry routine is called, and can be used when 4431 * main is not available in the symbol table. 4432 */ 4433 void 4434 _r_debug_postinit(struct link_map *m __unused) 4435 { 4436 4437 /* See r_debug_state(). */ 4438 __compiler_membar(); 4439 } 4440 4441 static void 4442 release_object(Obj_Entry *obj) 4443 { 4444 4445 if (obj->holdcount > 0) { 4446 obj->unholdfree = true; 4447 return; 4448 } 4449 munmap(obj->mapbase, obj->mapsize); 4450 linkmap_delete(obj); 4451 obj_free(obj); 4452 } 4453 4454 /* 4455 * Get address of the pointer variable in the main program. 4456 * Prefer non-weak symbol over the weak one. 4457 */ 4458 static const void ** 4459 get_program_var_addr(const char *name, RtldLockState *lockstate) 4460 { 4461 SymLook req; 4462 DoneList donelist; 4463 4464 symlook_init(&req, name); 4465 req.lockstate = lockstate; 4466 donelist_init(&donelist); 4467 if (symlook_global(&req, &donelist) != 0) 4468 return (NULL); 4469 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 4470 return ((const void **)make_function_pointer(req.sym_out, 4471 req.defobj_out)); 4472 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 4473 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 4474 else 4475 return ((const void **)(req.defobj_out->relocbase + 4476 req.sym_out->st_value)); 4477 } 4478 4479 /* 4480 * Set a pointer variable in the main program to the given value. This 4481 * is used to set key variables such as "environ" before any of the 4482 * init functions are called. 4483 */ 4484 static void 4485 set_program_var(const char *name, const void *value) 4486 { 4487 const void **addr; 4488 4489 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4490 dbg("\"%s\": *%p <-- %p", name, addr, value); 4491 *addr = value; 4492 } 4493 } 4494 4495 /* 4496 * Search the global objects, including dependencies and main object, 4497 * for the given symbol. 4498 */ 4499 static int 4500 symlook_global(SymLook *req, DoneList *donelist) 4501 { 4502 SymLook req1; 4503 const Objlist_Entry *elm; 4504 int res; 4505 4506 symlook_init_from_req(&req1, req); 4507 4508 /* Search all objects loaded at program start up. */ 4509 if (req->defobj_out == NULL || (ld_dynamic_weak && 4510 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK)) { 4511 res = symlook_list(&req1, &list_main, donelist); 4512 if (res == 0 && (!ld_dynamic_weak || req->defobj_out == NULL || 4513 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4514 req->sym_out = req1.sym_out; 4515 req->defobj_out = req1.defobj_out; 4516 assert(req->defobj_out != NULL); 4517 } 4518 } 4519 4520 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4521 STAILQ_FOREACH(elm, &list_global, link) { 4522 if (req->defobj_out != NULL && (!ld_dynamic_weak || 4523 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)) 4524 break; 4525 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 4526 if (res == 0 && (req->defobj_out == NULL || 4527 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4528 req->sym_out = req1.sym_out; 4529 req->defobj_out = req1.defobj_out; 4530 assert(req->defobj_out != NULL); 4531 } 4532 } 4533 4534 return (req->sym_out != NULL ? 0 : ESRCH); 4535 } 4536 4537 /* 4538 * Given a symbol name in a referencing object, find the corresponding 4539 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4540 * no definition was found. Returns a pointer to the Obj_Entry of the 4541 * defining object via the reference parameter DEFOBJ_OUT. 4542 */ 4543 static int 4544 symlook_default(SymLook *req, const Obj_Entry *refobj) 4545 { 4546 DoneList donelist; 4547 const Objlist_Entry *elm; 4548 SymLook req1; 4549 int res; 4550 4551 donelist_init(&donelist); 4552 symlook_init_from_req(&req1, req); 4553 4554 /* 4555 * Look first in the referencing object if linked symbolically, 4556 * and similarly handle protected symbols. 4557 */ 4558 res = symlook_obj(&req1, refobj); 4559 if (res == 0 && (refobj->symbolic || 4560 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4561 req->sym_out = req1.sym_out; 4562 req->defobj_out = req1.defobj_out; 4563 assert(req->defobj_out != NULL); 4564 } 4565 if (refobj->symbolic || req->defobj_out != NULL) 4566 donelist_check(&donelist, refobj); 4567 4568 symlook_global(req, &donelist); 4569 4570 /* Search all dlopened DAGs containing the referencing object. */ 4571 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4572 if (req->sym_out != NULL && (!ld_dynamic_weak || 4573 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)) 4574 break; 4575 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4576 if (res == 0 && (req->sym_out == NULL || 4577 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4578 req->sym_out = req1.sym_out; 4579 req->defobj_out = req1.defobj_out; 4580 assert(req->defobj_out != NULL); 4581 } 4582 } 4583 4584 /* 4585 * Search the dynamic linker itself, and possibly resolve the 4586 * symbol from there. This is how the application links to 4587 * dynamic linker services such as dlopen. 4588 */ 4589 if (req->sym_out == NULL || 4590 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4591 res = symlook_obj(&req1, &obj_rtld); 4592 if (res == 0) { 4593 req->sym_out = req1.sym_out; 4594 req->defobj_out = req1.defobj_out; 4595 assert(req->defobj_out != NULL); 4596 } 4597 } 4598 4599 return (req->sym_out != NULL ? 0 : ESRCH); 4600 } 4601 4602 static int 4603 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4604 { 4605 const Elf_Sym *def; 4606 const Obj_Entry *defobj; 4607 const Objlist_Entry *elm; 4608 SymLook req1; 4609 int res; 4610 4611 def = NULL; 4612 defobj = NULL; 4613 STAILQ_FOREACH(elm, objlist, link) { 4614 if (donelist_check(dlp, elm->obj)) 4615 continue; 4616 symlook_init_from_req(&req1, req); 4617 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4618 if (def == NULL || (ld_dynamic_weak && 4619 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4620 def = req1.sym_out; 4621 defobj = req1.defobj_out; 4622 if (!ld_dynamic_weak || ELF_ST_BIND(def->st_info) != STB_WEAK) 4623 break; 4624 } 4625 } 4626 } 4627 if (def != NULL) { 4628 req->sym_out = def; 4629 req->defobj_out = defobj; 4630 return (0); 4631 } 4632 return (ESRCH); 4633 } 4634 4635 /* 4636 * Search the chain of DAGS cointed to by the given Needed_Entry 4637 * for a symbol of the given name. Each DAG is scanned completely 4638 * before advancing to the next one. Returns a pointer to the symbol, 4639 * or NULL if no definition was found. 4640 */ 4641 static int 4642 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4643 { 4644 const Elf_Sym *def; 4645 const Needed_Entry *n; 4646 const Obj_Entry *defobj; 4647 SymLook req1; 4648 int res; 4649 4650 def = NULL; 4651 defobj = NULL; 4652 symlook_init_from_req(&req1, req); 4653 for (n = needed; n != NULL; n = n->next) { 4654 if (n->obj == NULL || 4655 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4656 continue; 4657 if (def == NULL || (ld_dynamic_weak && 4658 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4659 def = req1.sym_out; 4660 defobj = req1.defobj_out; 4661 if (!ld_dynamic_weak || ELF_ST_BIND(def->st_info) != STB_WEAK) 4662 break; 4663 } 4664 } 4665 if (def != NULL) { 4666 req->sym_out = def; 4667 req->defobj_out = defobj; 4668 return (0); 4669 } 4670 return (ESRCH); 4671 } 4672 4673 /* 4674 * Search the symbol table of a single shared object for a symbol of 4675 * the given name and version, if requested. Returns a pointer to the 4676 * symbol, or NULL if no definition was found. If the object is 4677 * filter, return filtered symbol from filtee. 4678 * 4679 * The symbol's hash value is passed in for efficiency reasons; that 4680 * eliminates many recomputations of the hash value. 4681 */ 4682 int 4683 symlook_obj(SymLook *req, const Obj_Entry *obj) 4684 { 4685 DoneList donelist; 4686 SymLook req1; 4687 int flags, res, mres; 4688 4689 /* 4690 * If there is at least one valid hash at this point, we prefer to 4691 * use the faster GNU version if available. 4692 */ 4693 if (obj->valid_hash_gnu) 4694 mres = symlook_obj1_gnu(req, obj); 4695 else if (obj->valid_hash_sysv) 4696 mres = symlook_obj1_sysv(req, obj); 4697 else 4698 return (EINVAL); 4699 4700 if (mres == 0) { 4701 if (obj->needed_filtees != NULL) { 4702 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4703 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4704 donelist_init(&donelist); 4705 symlook_init_from_req(&req1, req); 4706 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4707 if (res == 0) { 4708 req->sym_out = req1.sym_out; 4709 req->defobj_out = req1.defobj_out; 4710 } 4711 return (res); 4712 } 4713 if (obj->needed_aux_filtees != NULL) { 4714 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4715 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4716 donelist_init(&donelist); 4717 symlook_init_from_req(&req1, req); 4718 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4719 if (res == 0) { 4720 req->sym_out = req1.sym_out; 4721 req->defobj_out = req1.defobj_out; 4722 return (res); 4723 } 4724 } 4725 } 4726 return (mres); 4727 } 4728 4729 /* Symbol match routine common to both hash functions */ 4730 static bool 4731 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4732 const unsigned long symnum) 4733 { 4734 Elf_Versym verndx; 4735 const Elf_Sym *symp; 4736 const char *strp; 4737 4738 symp = obj->symtab + symnum; 4739 strp = obj->strtab + symp->st_name; 4740 4741 switch (ELF_ST_TYPE(symp->st_info)) { 4742 case STT_FUNC: 4743 case STT_NOTYPE: 4744 case STT_OBJECT: 4745 case STT_COMMON: 4746 case STT_GNU_IFUNC: 4747 if (symp->st_value == 0) 4748 return (false); 4749 /* fallthrough */ 4750 case STT_TLS: 4751 if (symp->st_shndx != SHN_UNDEF) 4752 break; 4753 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4754 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4755 break; 4756 /* fallthrough */ 4757 default: 4758 return (false); 4759 } 4760 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4761 return (false); 4762 4763 if (req->ventry == NULL) { 4764 if (obj->versyms != NULL) { 4765 verndx = VER_NDX(obj->versyms[symnum]); 4766 if (verndx > obj->vernum) { 4767 _rtld_error( 4768 "%s: symbol %s references wrong version %d", 4769 obj->path, obj->strtab + symnum, verndx); 4770 return (false); 4771 } 4772 /* 4773 * If we are not called from dlsym (i.e. this 4774 * is a normal relocation from unversioned 4775 * binary), accept the symbol immediately if 4776 * it happens to have first version after this 4777 * shared object became versioned. Otherwise, 4778 * if symbol is versioned and not hidden, 4779 * remember it. If it is the only symbol with 4780 * this name exported by the shared object, it 4781 * will be returned as a match by the calling 4782 * function. If symbol is global (verndx < 2) 4783 * accept it unconditionally. 4784 */ 4785 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4786 verndx == VER_NDX_GIVEN) { 4787 result->sym_out = symp; 4788 return (true); 4789 } 4790 else if (verndx >= VER_NDX_GIVEN) { 4791 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4792 == 0) { 4793 if (result->vsymp == NULL) 4794 result->vsymp = symp; 4795 result->vcount++; 4796 } 4797 return (false); 4798 } 4799 } 4800 result->sym_out = symp; 4801 return (true); 4802 } 4803 if (obj->versyms == NULL) { 4804 if (object_match_name(obj, req->ventry->name)) { 4805 _rtld_error("%s: object %s should provide version %s " 4806 "for symbol %s", obj_rtld.path, obj->path, 4807 req->ventry->name, obj->strtab + symnum); 4808 return (false); 4809 } 4810 } else { 4811 verndx = VER_NDX(obj->versyms[symnum]); 4812 if (verndx > obj->vernum) { 4813 _rtld_error("%s: symbol %s references wrong version %d", 4814 obj->path, obj->strtab + symnum, verndx); 4815 return (false); 4816 } 4817 if (obj->vertab[verndx].hash != req->ventry->hash || 4818 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4819 /* 4820 * Version does not match. Look if this is a 4821 * global symbol and if it is not hidden. If 4822 * global symbol (verndx < 2) is available, 4823 * use it. Do not return symbol if we are 4824 * called by dlvsym, because dlvsym looks for 4825 * a specific version and default one is not 4826 * what dlvsym wants. 4827 */ 4828 if ((req->flags & SYMLOOK_DLSYM) || 4829 (verndx >= VER_NDX_GIVEN) || 4830 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4831 return (false); 4832 } 4833 } 4834 result->sym_out = symp; 4835 return (true); 4836 } 4837 4838 /* 4839 * Search for symbol using SysV hash function. 4840 * obj->buckets is known not to be NULL at this point; the test for this was 4841 * performed with the obj->valid_hash_sysv assignment. 4842 */ 4843 static int 4844 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4845 { 4846 unsigned long symnum; 4847 Sym_Match_Result matchres; 4848 4849 matchres.sym_out = NULL; 4850 matchres.vsymp = NULL; 4851 matchres.vcount = 0; 4852 4853 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4854 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4855 if (symnum >= obj->nchains) 4856 return (ESRCH); /* Bad object */ 4857 4858 if (matched_symbol(req, obj, &matchres, symnum)) { 4859 req->sym_out = matchres.sym_out; 4860 req->defobj_out = obj; 4861 return (0); 4862 } 4863 } 4864 if (matchres.vcount == 1) { 4865 req->sym_out = matchres.vsymp; 4866 req->defobj_out = obj; 4867 return (0); 4868 } 4869 return (ESRCH); 4870 } 4871 4872 /* Search for symbol using GNU hash function */ 4873 static int 4874 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4875 { 4876 Elf_Addr bloom_word; 4877 const Elf32_Word *hashval; 4878 Elf32_Word bucket; 4879 Sym_Match_Result matchres; 4880 unsigned int h1, h2; 4881 unsigned long symnum; 4882 4883 matchres.sym_out = NULL; 4884 matchres.vsymp = NULL; 4885 matchres.vcount = 0; 4886 4887 /* Pick right bitmask word from Bloom filter array */ 4888 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4889 obj->maskwords_bm_gnu]; 4890 4891 /* Calculate modulus word size of gnu hash and its derivative */ 4892 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4893 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4894 4895 /* Filter out the "definitely not in set" queries */ 4896 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4897 return (ESRCH); 4898 4899 /* Locate hash chain and corresponding value element*/ 4900 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4901 if (bucket == 0) 4902 return (ESRCH); 4903 hashval = &obj->chain_zero_gnu[bucket]; 4904 do { 4905 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4906 symnum = hashval - obj->chain_zero_gnu; 4907 if (matched_symbol(req, obj, &matchres, symnum)) { 4908 req->sym_out = matchres.sym_out; 4909 req->defobj_out = obj; 4910 return (0); 4911 } 4912 } 4913 } while ((*hashval++ & 1) == 0); 4914 if (matchres.vcount == 1) { 4915 req->sym_out = matchres.vsymp; 4916 req->defobj_out = obj; 4917 return (0); 4918 } 4919 return (ESRCH); 4920 } 4921 4922 static void 4923 trace_calc_fmts(const char **main_local, const char **fmt1, const char **fmt2) 4924 { 4925 *main_local = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_PROGNAME); 4926 if (*main_local == NULL) 4927 *main_local = ""; 4928 4929 *fmt1 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT1); 4930 if (*fmt1 == NULL) 4931 *fmt1 = "\t%o => %p (%x)\n"; 4932 4933 *fmt2 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT2); 4934 if (*fmt2 == NULL) 4935 *fmt2 = "\t%o (%x)\n"; 4936 } 4937 4938 static void 4939 trace_print_obj(Obj_Entry *obj, const char *name, const char *path, 4940 const char *main_local, const char *fmt1, const char *fmt2) 4941 { 4942 const char *fmt; 4943 int c; 4944 4945 fmt = strncmp(name, "lib", 3) == 0 ? fmt1 : fmt2; /* XXX bogus */ 4946 while ((c = *fmt++) != '\0') { 4947 switch (c) { 4948 default: 4949 rtld_putchar(c); 4950 continue; 4951 case '\\': 4952 switch (c = *fmt) { 4953 case '\0': 4954 continue; 4955 case 'n': 4956 rtld_putchar('\n'); 4957 break; 4958 case 't': 4959 rtld_putchar('\t'); 4960 break; 4961 } 4962 break; 4963 case '%': 4964 switch (c = *fmt) { 4965 case '\0': 4966 continue; 4967 case '%': 4968 default: 4969 rtld_putchar(c); 4970 break; 4971 case 'A': 4972 rtld_putstr(main_local); 4973 break; 4974 case 'a': 4975 rtld_putstr(obj_main->path); 4976 break; 4977 case 'o': 4978 rtld_putstr(name); 4979 break; 4980 case 'p': 4981 rtld_putstr(path); 4982 break; 4983 case 'x': 4984 rtld_printf("%p", obj != NULL ? 4985 obj->mapbase : NULL); 4986 break; 4987 } 4988 break; 4989 } 4990 ++fmt; 4991 } 4992 } 4993 4994 static void 4995 trace_loaded_objects(Obj_Entry *obj, bool show_preload) 4996 { 4997 const char *fmt1, *fmt2, *main_local; 4998 const char *name, *path; 4999 bool first_spurious, list_containers; 5000 5001 trace_calc_fmts(&main_local, &fmt1, &fmt2); 5002 list_containers = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_ALL) != NULL; 5003 5004 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 5005 Needed_Entry *needed; 5006 5007 if (obj->marker) 5008 continue; 5009 if (list_containers && obj->needed != NULL) 5010 rtld_printf("%s:\n", obj->path); 5011 for (needed = obj->needed; needed; needed = needed->next) { 5012 if (needed->obj != NULL) { 5013 if (needed->obj->traced && !list_containers) 5014 continue; 5015 needed->obj->traced = true; 5016 path = needed->obj->path; 5017 } else 5018 path = "not found"; 5019 5020 name = obj->strtab + needed->name; 5021 trace_print_obj(obj, name, path, main_local, 5022 fmt1, fmt2); 5023 } 5024 } 5025 5026 if (show_preload) { 5027 first_spurious = true; 5028 TAILQ_FOREACH(obj, &obj_list, next) { 5029 if (obj->marker || obj == obj_main || obj->traced) 5030 continue; 5031 5032 if (first_spurious) { 5033 rtld_printf("[preloaded]\n"); 5034 first_spurious = false; 5035 } 5036 Name_Entry *fname = STAILQ_FIRST(&obj->names); 5037 name = fname == NULL ? "<unknown>" : fname->name; 5038 trace_print_obj(obj, name, obj->path, main_local, 5039 fmt1, fmt2); 5040 } 5041 } 5042 } 5043 5044 /* 5045 * Unload a dlopened object and its dependencies from memory and from 5046 * our data structures. It is assumed that the DAG rooted in the 5047 * object has already been unreferenced, and that the object has a 5048 * reference count of 0. 5049 */ 5050 static void 5051 unload_object(Obj_Entry *root, RtldLockState *lockstate) 5052 { 5053 Obj_Entry marker, *obj, *next; 5054 5055 assert(root->refcount == 0); 5056 5057 /* 5058 * Pass over the DAG removing unreferenced objects from 5059 * appropriate lists. 5060 */ 5061 unlink_object(root); 5062 5063 /* Unmap all objects that are no longer referenced. */ 5064 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 5065 next = TAILQ_NEXT(obj, next); 5066 if (obj->marker || obj->refcount != 0) 5067 continue; 5068 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 5069 obj->mapsize, 0, obj->path); 5070 dbg("unloading \"%s\"", obj->path); 5071 /* 5072 * Unlink the object now to prevent new references from 5073 * being acquired while the bind lock is dropped in 5074 * recursive dlclose() invocations. 5075 */ 5076 TAILQ_REMOVE(&obj_list, obj, next); 5077 obj_count--; 5078 5079 if (obj->filtees_loaded) { 5080 if (next != NULL) { 5081 init_marker(&marker); 5082 TAILQ_INSERT_BEFORE(next, &marker, next); 5083 unload_filtees(obj, lockstate); 5084 next = TAILQ_NEXT(&marker, next); 5085 TAILQ_REMOVE(&obj_list, &marker, next); 5086 } else 5087 unload_filtees(obj, lockstate); 5088 } 5089 release_object(obj); 5090 } 5091 } 5092 5093 static void 5094 unlink_object(Obj_Entry *root) 5095 { 5096 Objlist_Entry *elm; 5097 5098 if (root->refcount == 0) { 5099 /* Remove the object from the RTLD_GLOBAL list. */ 5100 objlist_remove(&list_global, root); 5101 5102 /* Remove the object from all objects' DAG lists. */ 5103 STAILQ_FOREACH(elm, &root->dagmembers, link) { 5104 objlist_remove(&elm->obj->dldags, root); 5105 if (elm->obj != root) 5106 unlink_object(elm->obj); 5107 } 5108 } 5109 } 5110 5111 static void 5112 ref_dag(Obj_Entry *root) 5113 { 5114 Objlist_Entry *elm; 5115 5116 assert(root->dag_inited); 5117 STAILQ_FOREACH(elm, &root->dagmembers, link) 5118 elm->obj->refcount++; 5119 } 5120 5121 static void 5122 unref_dag(Obj_Entry *root) 5123 { 5124 Objlist_Entry *elm; 5125 5126 assert(root->dag_inited); 5127 STAILQ_FOREACH(elm, &root->dagmembers, link) 5128 elm->obj->refcount--; 5129 } 5130 5131 /* 5132 * Common code for MD __tls_get_addr(). 5133 */ 5134 static void * 5135 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset, bool locked) 5136 { 5137 Elf_Addr *newdtv, *dtv; 5138 RtldLockState lockstate; 5139 int to_copy; 5140 5141 dtv = *dtvp; 5142 /* Check dtv generation in case new modules have arrived */ 5143 if (dtv[0] != tls_dtv_generation) { 5144 if (!locked) 5145 wlock_acquire(rtld_bind_lock, &lockstate); 5146 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5147 to_copy = dtv[1]; 5148 if (to_copy > tls_max_index) 5149 to_copy = tls_max_index; 5150 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 5151 newdtv[0] = tls_dtv_generation; 5152 newdtv[1] = tls_max_index; 5153 free(dtv); 5154 if (!locked) 5155 lock_release(rtld_bind_lock, &lockstate); 5156 dtv = *dtvp = newdtv; 5157 } 5158 5159 /* Dynamically allocate module TLS if necessary */ 5160 if (dtv[index + 1] == 0) { 5161 /* Signal safe, wlock will block out signals. */ 5162 if (!locked) 5163 wlock_acquire(rtld_bind_lock, &lockstate); 5164 if (!dtv[index + 1]) 5165 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 5166 if (!locked) 5167 lock_release(rtld_bind_lock, &lockstate); 5168 } 5169 return ((void *)(dtv[index + 1] + offset)); 5170 } 5171 5172 void * 5173 tls_get_addr_common(uintptr_t **dtvp, int index, size_t offset) 5174 { 5175 uintptr_t *dtv; 5176 5177 dtv = *dtvp; 5178 /* Check dtv generation in case new modules have arrived */ 5179 if (__predict_true(dtv[0] == tls_dtv_generation && 5180 dtv[index + 1] != 0)) 5181 return ((void *)(dtv[index + 1] + offset)); 5182 return (tls_get_addr_slow(dtvp, index, offset, false)); 5183 } 5184 5185 #ifdef TLS_VARIANT_I 5186 5187 /* 5188 * Return pointer to allocated TLS block 5189 */ 5190 static void * 5191 get_tls_block_ptr(void *tcb, size_t tcbsize) 5192 { 5193 size_t extra_size, post_size, pre_size, tls_block_size; 5194 size_t tls_init_align; 5195 5196 tls_init_align = MAX(obj_main->tlsalign, 1); 5197 5198 /* Compute fragments sizes. */ 5199 extra_size = tcbsize - TLS_TCB_SIZE; 5200 post_size = calculate_tls_post_size(tls_init_align); 5201 tls_block_size = tcbsize + post_size; 5202 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 5203 5204 return ((char *)tcb - pre_size - extra_size); 5205 } 5206 5207 /* 5208 * Allocate Static TLS using the Variant I method. 5209 * 5210 * For details on the layout, see lib/libc/gen/tls.c. 5211 * 5212 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as 5213 * it is based on tls_last_offset, and TLS offsets here are really TCB 5214 * offsets, whereas libc's tls_static_space is just the executable's static 5215 * TLS segment. 5216 */ 5217 void * 5218 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 5219 { 5220 Obj_Entry *obj; 5221 char *tls_block; 5222 Elf_Addr *dtv, **tcb; 5223 Elf_Addr addr; 5224 Elf_Addr i; 5225 size_t extra_size, maxalign, post_size, pre_size, tls_block_size; 5226 size_t tls_init_align, tls_init_offset; 5227 5228 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 5229 return (oldtcb); 5230 5231 assert(tcbsize >= TLS_TCB_SIZE); 5232 maxalign = MAX(tcbalign, tls_static_max_align); 5233 tls_init_align = MAX(obj_main->tlsalign, 1); 5234 5235 /* Compute fragmets sizes. */ 5236 extra_size = tcbsize - TLS_TCB_SIZE; 5237 post_size = calculate_tls_post_size(tls_init_align); 5238 tls_block_size = tcbsize + post_size; 5239 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 5240 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size; 5241 5242 /* Allocate whole TLS block */ 5243 tls_block = malloc_aligned(tls_block_size, maxalign, 0); 5244 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size); 5245 5246 if (oldtcb != NULL) { 5247 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize), 5248 tls_static_space); 5249 free_aligned(get_tls_block_ptr(oldtcb, tcbsize)); 5250 5251 /* Adjust the DTV. */ 5252 dtv = tcb[0]; 5253 for (i = 0; i < dtv[1]; i++) { 5254 if (dtv[i+2] >= (Elf_Addr)oldtcb && 5255 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 5256 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb; 5257 } 5258 } 5259 } else { 5260 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5261 tcb[0] = dtv; 5262 dtv[0] = tls_dtv_generation; 5263 dtv[1] = tls_max_index; 5264 5265 for (obj = globallist_curr(objs); obj != NULL; 5266 obj = globallist_next(obj)) { 5267 if (obj->tlsoffset == 0) 5268 continue; 5269 tls_init_offset = obj->tlspoffset & (obj->tlsalign - 1); 5270 addr = (Elf_Addr)tcb + obj->tlsoffset; 5271 if (tls_init_offset > 0) 5272 memset((void *)addr, 0, tls_init_offset); 5273 if (obj->tlsinitsize > 0) { 5274 memcpy((void *)(addr + tls_init_offset), obj->tlsinit, 5275 obj->tlsinitsize); 5276 } 5277 if (obj->tlssize > obj->tlsinitsize) { 5278 memset((void *)(addr + tls_init_offset + obj->tlsinitsize), 5279 0, obj->tlssize - obj->tlsinitsize - tls_init_offset); 5280 } 5281 dtv[obj->tlsindex + 1] = addr; 5282 } 5283 } 5284 5285 return (tcb); 5286 } 5287 5288 void 5289 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused) 5290 { 5291 Elf_Addr *dtv; 5292 Elf_Addr tlsstart, tlsend; 5293 size_t post_size; 5294 size_t dtvsize, i, tls_init_align; 5295 5296 assert(tcbsize >= TLS_TCB_SIZE); 5297 tls_init_align = MAX(obj_main->tlsalign, 1); 5298 5299 /* Compute fragments sizes. */ 5300 post_size = calculate_tls_post_size(tls_init_align); 5301 5302 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size; 5303 tlsend = (Elf_Addr)tcb + tls_static_space; 5304 5305 dtv = *(Elf_Addr **)tcb; 5306 dtvsize = dtv[1]; 5307 for (i = 0; i < dtvsize; i++) { 5308 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 5309 free((void*)dtv[i+2]); 5310 } 5311 } 5312 free(dtv); 5313 free_aligned(get_tls_block_ptr(tcb, tcbsize)); 5314 } 5315 5316 #endif /* TLS_VARIANT_I */ 5317 5318 #ifdef TLS_VARIANT_II 5319 5320 /* 5321 * Allocate Static TLS using the Variant II method. 5322 */ 5323 void * 5324 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 5325 { 5326 Obj_Entry *obj; 5327 size_t size, ralign; 5328 char *tls; 5329 Elf_Addr *dtv, *olddtv; 5330 Elf_Addr segbase, oldsegbase, addr; 5331 size_t i; 5332 5333 ralign = tcbalign; 5334 if (tls_static_max_align > ralign) 5335 ralign = tls_static_max_align; 5336 size = roundup(tls_static_space, ralign) + roundup(tcbsize, ralign); 5337 5338 assert(tcbsize >= 2*sizeof(Elf_Addr)); 5339 tls = malloc_aligned(size, ralign, 0 /* XXX */); 5340 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5341 5342 segbase = (Elf_Addr)(tls + roundup(tls_static_space, ralign)); 5343 ((Elf_Addr *)segbase)[0] = segbase; 5344 ((Elf_Addr *)segbase)[1] = (Elf_Addr) dtv; 5345 5346 dtv[0] = tls_dtv_generation; 5347 dtv[1] = tls_max_index; 5348 5349 if (oldtls) { 5350 /* 5351 * Copy the static TLS block over whole. 5352 */ 5353 oldsegbase = (Elf_Addr) oldtls; 5354 memcpy((void *)(segbase - tls_static_space), 5355 (const void *)(oldsegbase - tls_static_space), 5356 tls_static_space); 5357 5358 /* 5359 * If any dynamic TLS blocks have been created tls_get_addr(), 5360 * move them over. 5361 */ 5362 olddtv = ((Elf_Addr **)oldsegbase)[1]; 5363 for (i = 0; i < olddtv[1]; i++) { 5364 if (olddtv[i + 2] < oldsegbase - size || 5365 olddtv[i + 2] > oldsegbase) { 5366 dtv[i + 2] = olddtv[i + 2]; 5367 olddtv[i + 2] = 0; 5368 } 5369 } 5370 5371 /* 5372 * We assume that this block was the one we created with 5373 * allocate_initial_tls(). 5374 */ 5375 free_tls(oldtls, 2 * sizeof(Elf_Addr), sizeof(Elf_Addr)); 5376 } else { 5377 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 5378 if (obj->marker || obj->tlsoffset == 0) 5379 continue; 5380 addr = segbase - obj->tlsoffset; 5381 memset((void *)(addr + obj->tlsinitsize), 5382 0, obj->tlssize - obj->tlsinitsize); 5383 if (obj->tlsinit) { 5384 memcpy((void *)addr, obj->tlsinit, obj->tlsinitsize); 5385 obj->static_tls_copied = true; 5386 } 5387 dtv[obj->tlsindex + 1] = addr; 5388 } 5389 } 5390 5391 return ((void *)segbase); 5392 } 5393 5394 void 5395 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign) 5396 { 5397 Elf_Addr* dtv; 5398 size_t size, ralign; 5399 int dtvsize, i; 5400 Elf_Addr tlsstart, tlsend; 5401 5402 /* 5403 * Figure out the size of the initial TLS block so that we can 5404 * find stuff which ___tls_get_addr() allocated dynamically. 5405 */ 5406 ralign = tcbalign; 5407 if (tls_static_max_align > ralign) 5408 ralign = tls_static_max_align; 5409 size = roundup(tls_static_space, ralign); 5410 5411 dtv = ((Elf_Addr **)tls)[1]; 5412 dtvsize = dtv[1]; 5413 tlsend = (Elf_Addr)tls; 5414 tlsstart = tlsend - size; 5415 for (i = 0; i < dtvsize; i++) { 5416 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || 5417 dtv[i + 2] > tlsend)) { 5418 free_aligned((void *)dtv[i + 2]); 5419 } 5420 } 5421 5422 free_aligned((void *)tlsstart); 5423 free((void *)dtv); 5424 } 5425 5426 #endif /* TLS_VARIANT_II */ 5427 5428 /* 5429 * Allocate TLS block for module with given index. 5430 */ 5431 void * 5432 allocate_module_tls(int index) 5433 { 5434 Obj_Entry *obj; 5435 char *p; 5436 5437 TAILQ_FOREACH(obj, &obj_list, next) { 5438 if (obj->marker) 5439 continue; 5440 if (obj->tlsindex == index) 5441 break; 5442 } 5443 if (obj == NULL) { 5444 _rtld_error("Can't find module with TLS index %d", index); 5445 rtld_die(); 5446 } 5447 5448 p = malloc_aligned(obj->tlssize, obj->tlsalign, obj->tlspoffset); 5449 memcpy(p, obj->tlsinit, obj->tlsinitsize); 5450 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 5451 return (p); 5452 } 5453 5454 bool 5455 allocate_tls_offset(Obj_Entry *obj) 5456 { 5457 size_t off; 5458 5459 if (obj->tls_done) 5460 return (true); 5461 5462 if (obj->tlssize == 0) { 5463 obj->tls_done = true; 5464 return (true); 5465 } 5466 5467 if (tls_last_offset == 0) 5468 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign, 5469 obj->tlspoffset); 5470 else 5471 off = calculate_tls_offset(tls_last_offset, tls_last_size, 5472 obj->tlssize, obj->tlsalign, obj->tlspoffset); 5473 5474 obj->tlsoffset = off; 5475 #ifdef TLS_VARIANT_I 5476 off += obj->tlssize; 5477 #endif 5478 5479 /* 5480 * If we have already fixed the size of the static TLS block, we 5481 * must stay within that size. When allocating the static TLS, we 5482 * leave a small amount of space spare to be used for dynamically 5483 * loading modules which use static TLS. 5484 */ 5485 if (tls_static_space != 0) { 5486 if (off > tls_static_space) 5487 return (false); 5488 } else if (obj->tlsalign > tls_static_max_align) { 5489 tls_static_max_align = obj->tlsalign; 5490 } 5491 5492 tls_last_offset = off; 5493 tls_last_size = obj->tlssize; 5494 obj->tls_done = true; 5495 5496 return (true); 5497 } 5498 5499 void 5500 free_tls_offset(Obj_Entry *obj) 5501 { 5502 5503 /* 5504 * If we were the last thing to allocate out of the static TLS 5505 * block, we give our space back to the 'allocator'. This is a 5506 * simplistic workaround to allow libGL.so.1 to be loaded and 5507 * unloaded multiple times. 5508 */ 5509 size_t off = obj->tlsoffset; 5510 #ifdef TLS_VARIANT_I 5511 off += obj->tlssize; 5512 #endif 5513 if (off == tls_last_offset) { 5514 tls_last_offset -= obj->tlssize; 5515 tls_last_size = 0; 5516 } 5517 } 5518 5519 void * 5520 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 5521 { 5522 void *ret; 5523 RtldLockState lockstate; 5524 5525 wlock_acquire(rtld_bind_lock, &lockstate); 5526 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 5527 tcbsize, tcbalign); 5528 lock_release(rtld_bind_lock, &lockstate); 5529 return (ret); 5530 } 5531 5532 void 5533 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 5534 { 5535 RtldLockState lockstate; 5536 5537 wlock_acquire(rtld_bind_lock, &lockstate); 5538 free_tls(tcb, tcbsize, tcbalign); 5539 lock_release(rtld_bind_lock, &lockstate); 5540 } 5541 5542 static void 5543 object_add_name(Obj_Entry *obj, const char *name) 5544 { 5545 Name_Entry *entry; 5546 size_t len; 5547 5548 len = strlen(name); 5549 entry = malloc(sizeof(Name_Entry) + len); 5550 5551 if (entry != NULL) { 5552 strcpy(entry->name, name); 5553 STAILQ_INSERT_TAIL(&obj->names, entry, link); 5554 } 5555 } 5556 5557 static int 5558 object_match_name(const Obj_Entry *obj, const char *name) 5559 { 5560 Name_Entry *entry; 5561 5562 STAILQ_FOREACH(entry, &obj->names, link) { 5563 if (strcmp(name, entry->name) == 0) 5564 return (1); 5565 } 5566 return (0); 5567 } 5568 5569 static Obj_Entry * 5570 locate_dependency(const Obj_Entry *obj, const char *name) 5571 { 5572 const Objlist_Entry *entry; 5573 const Needed_Entry *needed; 5574 5575 STAILQ_FOREACH(entry, &list_main, link) { 5576 if (object_match_name(entry->obj, name)) 5577 return (entry->obj); 5578 } 5579 5580 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5581 if (strcmp(obj->strtab + needed->name, name) == 0 || 5582 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5583 /* 5584 * If there is DT_NEEDED for the name we are looking for, 5585 * we are all set. Note that object might not be found if 5586 * dependency was not loaded yet, so the function can 5587 * return NULL here. This is expected and handled 5588 * properly by the caller. 5589 */ 5590 return (needed->obj); 5591 } 5592 } 5593 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5594 obj->path, name); 5595 rtld_die(); 5596 } 5597 5598 static int 5599 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5600 const Elf_Vernaux *vna) 5601 { 5602 const Elf_Verdef *vd; 5603 const char *vername; 5604 5605 vername = refobj->strtab + vna->vna_name; 5606 vd = depobj->verdef; 5607 if (vd == NULL) { 5608 _rtld_error("%s: version %s required by %s not defined", 5609 depobj->path, vername, refobj->path); 5610 return (-1); 5611 } 5612 for (;;) { 5613 if (vd->vd_version != VER_DEF_CURRENT) { 5614 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5615 depobj->path, vd->vd_version); 5616 return (-1); 5617 } 5618 if (vna->vna_hash == vd->vd_hash) { 5619 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5620 ((const char *)vd + vd->vd_aux); 5621 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5622 return (0); 5623 } 5624 if (vd->vd_next == 0) 5625 break; 5626 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5627 } 5628 if (vna->vna_flags & VER_FLG_WEAK) 5629 return (0); 5630 _rtld_error("%s: version %s required by %s not found", 5631 depobj->path, vername, refobj->path); 5632 return (-1); 5633 } 5634 5635 static int 5636 rtld_verify_object_versions(Obj_Entry *obj) 5637 { 5638 const Elf_Verneed *vn; 5639 const Elf_Verdef *vd; 5640 const Elf_Verdaux *vda; 5641 const Elf_Vernaux *vna; 5642 const Obj_Entry *depobj; 5643 int maxvernum, vernum; 5644 5645 if (obj->ver_checked) 5646 return (0); 5647 obj->ver_checked = true; 5648 5649 maxvernum = 0; 5650 /* 5651 * Walk over defined and required version records and figure out 5652 * max index used by any of them. Do very basic sanity checking 5653 * while there. 5654 */ 5655 vn = obj->verneed; 5656 while (vn != NULL) { 5657 if (vn->vn_version != VER_NEED_CURRENT) { 5658 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5659 obj->path, vn->vn_version); 5660 return (-1); 5661 } 5662 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5663 for (;;) { 5664 vernum = VER_NEED_IDX(vna->vna_other); 5665 if (vernum > maxvernum) 5666 maxvernum = vernum; 5667 if (vna->vna_next == 0) 5668 break; 5669 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5670 } 5671 if (vn->vn_next == 0) 5672 break; 5673 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5674 } 5675 5676 vd = obj->verdef; 5677 while (vd != NULL) { 5678 if (vd->vd_version != VER_DEF_CURRENT) { 5679 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5680 obj->path, vd->vd_version); 5681 return (-1); 5682 } 5683 vernum = VER_DEF_IDX(vd->vd_ndx); 5684 if (vernum > maxvernum) 5685 maxvernum = vernum; 5686 if (vd->vd_next == 0) 5687 break; 5688 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5689 } 5690 5691 if (maxvernum == 0) 5692 return (0); 5693 5694 /* 5695 * Store version information in array indexable by version index. 5696 * Verify that object version requirements are satisfied along the 5697 * way. 5698 */ 5699 obj->vernum = maxvernum + 1; 5700 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5701 5702 vd = obj->verdef; 5703 while (vd != NULL) { 5704 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5705 vernum = VER_DEF_IDX(vd->vd_ndx); 5706 assert(vernum <= maxvernum); 5707 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux); 5708 obj->vertab[vernum].hash = vd->vd_hash; 5709 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5710 obj->vertab[vernum].file = NULL; 5711 obj->vertab[vernum].flags = 0; 5712 } 5713 if (vd->vd_next == 0) 5714 break; 5715 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5716 } 5717 5718 vn = obj->verneed; 5719 while (vn != NULL) { 5720 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5721 if (depobj == NULL) 5722 return (-1); 5723 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5724 for (;;) { 5725 if (check_object_provided_version(obj, depobj, vna)) 5726 return (-1); 5727 vernum = VER_NEED_IDX(vna->vna_other); 5728 assert(vernum <= maxvernum); 5729 obj->vertab[vernum].hash = vna->vna_hash; 5730 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5731 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5732 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5733 VER_INFO_HIDDEN : 0; 5734 if (vna->vna_next == 0) 5735 break; 5736 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5737 } 5738 if (vn->vn_next == 0) 5739 break; 5740 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5741 } 5742 return (0); 5743 } 5744 5745 static int 5746 rtld_verify_versions(const Objlist *objlist) 5747 { 5748 Objlist_Entry *entry; 5749 int rc; 5750 5751 rc = 0; 5752 STAILQ_FOREACH(entry, objlist, link) { 5753 /* 5754 * Skip dummy objects or objects that have their version requirements 5755 * already checked. 5756 */ 5757 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5758 continue; 5759 if (rtld_verify_object_versions(entry->obj) == -1) { 5760 rc = -1; 5761 if (ld_tracing == NULL) 5762 break; 5763 } 5764 } 5765 if (rc == 0 || ld_tracing != NULL) 5766 rc = rtld_verify_object_versions(&obj_rtld); 5767 return (rc); 5768 } 5769 5770 const Ver_Entry * 5771 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5772 { 5773 Elf_Versym vernum; 5774 5775 if (obj->vertab) { 5776 vernum = VER_NDX(obj->versyms[symnum]); 5777 if (vernum >= obj->vernum) { 5778 _rtld_error("%s: symbol %s has wrong verneed value %d", 5779 obj->path, obj->strtab + symnum, vernum); 5780 } else if (obj->vertab[vernum].hash != 0) { 5781 return (&obj->vertab[vernum]); 5782 } 5783 } 5784 return (NULL); 5785 } 5786 5787 int 5788 _rtld_get_stack_prot(void) 5789 { 5790 5791 return (stack_prot); 5792 } 5793 5794 int 5795 _rtld_is_dlopened(void *arg) 5796 { 5797 Obj_Entry *obj; 5798 RtldLockState lockstate; 5799 int res; 5800 5801 rlock_acquire(rtld_bind_lock, &lockstate); 5802 obj = dlcheck(arg); 5803 if (obj == NULL) 5804 obj = obj_from_addr(arg); 5805 if (obj == NULL) { 5806 _rtld_error("No shared object contains address"); 5807 lock_release(rtld_bind_lock, &lockstate); 5808 return (-1); 5809 } 5810 res = obj->dlopened ? 1 : 0; 5811 lock_release(rtld_bind_lock, &lockstate); 5812 return (res); 5813 } 5814 5815 static int 5816 obj_remap_relro(Obj_Entry *obj, int prot) 5817 { 5818 5819 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5820 prot) == -1) { 5821 _rtld_error("%s: Cannot set relro protection to %#x: %s", 5822 obj->path, prot, rtld_strerror(errno)); 5823 return (-1); 5824 } 5825 return (0); 5826 } 5827 5828 static int 5829 obj_disable_relro(Obj_Entry *obj) 5830 { 5831 5832 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE)); 5833 } 5834 5835 static int 5836 obj_enforce_relro(Obj_Entry *obj) 5837 { 5838 5839 return (obj_remap_relro(obj, PROT_READ)); 5840 } 5841 5842 static void 5843 map_stacks_exec(RtldLockState *lockstate) 5844 { 5845 void (*thr_map_stacks_exec)(void); 5846 5847 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5848 return; 5849 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5850 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5851 if (thr_map_stacks_exec != NULL) { 5852 stack_prot |= PROT_EXEC; 5853 thr_map_stacks_exec(); 5854 } 5855 } 5856 5857 static void 5858 distribute_static_tls(Objlist *list, RtldLockState *lockstate) 5859 { 5860 Objlist_Entry *elm; 5861 Obj_Entry *obj; 5862 void (*distrib)(size_t, void *, size_t, size_t); 5863 5864 distrib = (void (*)(size_t, void *, size_t, size_t))(uintptr_t) 5865 get_program_var_addr("__pthread_distribute_static_tls", lockstate); 5866 if (distrib == NULL) 5867 return; 5868 STAILQ_FOREACH(elm, list, link) { 5869 obj = elm->obj; 5870 if (obj->marker || !obj->tls_done || obj->static_tls_copied) 5871 continue; 5872 distrib(obj->tlsoffset, obj->tlsinit, obj->tlsinitsize, 5873 obj->tlssize); 5874 obj->static_tls_copied = true; 5875 } 5876 } 5877 5878 void 5879 symlook_init(SymLook *dst, const char *name) 5880 { 5881 5882 bzero(dst, sizeof(*dst)); 5883 dst->name = name; 5884 dst->hash = elf_hash(name); 5885 dst->hash_gnu = gnu_hash(name); 5886 } 5887 5888 static void 5889 symlook_init_from_req(SymLook *dst, const SymLook *src) 5890 { 5891 5892 dst->name = src->name; 5893 dst->hash = src->hash; 5894 dst->hash_gnu = src->hash_gnu; 5895 dst->ventry = src->ventry; 5896 dst->flags = src->flags; 5897 dst->defobj_out = NULL; 5898 dst->sym_out = NULL; 5899 dst->lockstate = src->lockstate; 5900 } 5901 5902 static int 5903 open_binary_fd(const char *argv0, bool search_in_path, 5904 const char **binpath_res) 5905 { 5906 char *binpath, *pathenv, *pe, *res1; 5907 const char *res; 5908 int fd; 5909 5910 binpath = NULL; 5911 res = NULL; 5912 if (search_in_path && strchr(argv0, '/') == NULL) { 5913 binpath = xmalloc(PATH_MAX); 5914 pathenv = getenv("PATH"); 5915 if (pathenv == NULL) { 5916 _rtld_error("-p and no PATH environment variable"); 5917 rtld_die(); 5918 } 5919 pathenv = strdup(pathenv); 5920 if (pathenv == NULL) { 5921 _rtld_error("Cannot allocate memory"); 5922 rtld_die(); 5923 } 5924 fd = -1; 5925 errno = ENOENT; 5926 while ((pe = strsep(&pathenv, ":")) != NULL) { 5927 if (strlcpy(binpath, pe, PATH_MAX) >= PATH_MAX) 5928 continue; 5929 if (binpath[0] != '\0' && 5930 strlcat(binpath, "/", PATH_MAX) >= PATH_MAX) 5931 continue; 5932 if (strlcat(binpath, argv0, PATH_MAX) >= PATH_MAX) 5933 continue; 5934 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 5935 if (fd != -1 || errno != ENOENT) { 5936 res = binpath; 5937 break; 5938 } 5939 } 5940 free(pathenv); 5941 } else { 5942 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 5943 res = argv0; 5944 } 5945 5946 if (fd == -1) { 5947 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno)); 5948 rtld_die(); 5949 } 5950 if (res != NULL && res[0] != '/') { 5951 res1 = xmalloc(PATH_MAX); 5952 if (realpath(res, res1) != NULL) { 5953 if (res != argv0) 5954 free(__DECONST(char *, res)); 5955 res = res1; 5956 } else { 5957 free(res1); 5958 } 5959 } 5960 *binpath_res = res; 5961 return (fd); 5962 } 5963 5964 /* 5965 * Parse a set of command-line arguments. 5966 */ 5967 static int 5968 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp, 5969 const char **argv0, bool *dir_ignore) 5970 { 5971 const char *arg; 5972 char machine[64]; 5973 size_t sz; 5974 int arglen, fd, i, j, mib[2]; 5975 char opt; 5976 bool seen_b, seen_f; 5977 5978 dbg("Parsing command-line arguments"); 5979 *use_pathp = false; 5980 *fdp = -1; 5981 *dir_ignore = false; 5982 seen_b = seen_f = false; 5983 5984 for (i = 1; i < argc; i++ ) { 5985 arg = argv[i]; 5986 dbg("argv[%d]: '%s'", i, arg); 5987 5988 /* 5989 * rtld arguments end with an explicit "--" or with the first 5990 * non-prefixed argument. 5991 */ 5992 if (strcmp(arg, "--") == 0) { 5993 i++; 5994 break; 5995 } 5996 if (arg[0] != '-') 5997 break; 5998 5999 /* 6000 * All other arguments are single-character options that can 6001 * be combined, so we need to search through `arg` for them. 6002 */ 6003 arglen = strlen(arg); 6004 for (j = 1; j < arglen; j++) { 6005 opt = arg[j]; 6006 if (opt == 'h') { 6007 print_usage(argv[0]); 6008 _exit(0); 6009 } else if (opt == 'b') { 6010 if (seen_f) { 6011 _rtld_error("Both -b and -f specified"); 6012 rtld_die(); 6013 } 6014 i++; 6015 *argv0 = argv[i]; 6016 seen_b = true; 6017 break; 6018 } else if (opt == 'd') { 6019 *dir_ignore = true; 6020 break; 6021 } else if (opt == 'f') { 6022 if (seen_b) { 6023 _rtld_error("Both -b and -f specified"); 6024 rtld_die(); 6025 } 6026 6027 /* 6028 * -f XX can be used to specify a 6029 * descriptor for the binary named at 6030 * the command line (i.e., the later 6031 * argument will specify the process 6032 * name but the descriptor is what 6033 * will actually be executed). 6034 * 6035 * -f must be the last option in, e.g., -abcf. 6036 */ 6037 if (j != arglen - 1) { 6038 _rtld_error("Invalid options: %s", arg); 6039 rtld_die(); 6040 } 6041 i++; 6042 fd = parse_integer(argv[i]); 6043 if (fd == -1) { 6044 _rtld_error( 6045 "Invalid file descriptor: '%s'", 6046 argv[i]); 6047 rtld_die(); 6048 } 6049 *fdp = fd; 6050 seen_f = true; 6051 break; 6052 } else if (opt == 'p') { 6053 *use_pathp = true; 6054 } else if (opt == 'u') { 6055 trust = false; 6056 } else if (opt == 'v') { 6057 machine[0] = '\0'; 6058 mib[0] = CTL_HW; 6059 mib[1] = HW_MACHINE; 6060 sz = sizeof(machine); 6061 sysctl(mib, nitems(mib), machine, &sz, NULL, 0); 6062 ld_elf_hints_path = ld_get_env_var( 6063 LD_ELF_HINTS_PATH); 6064 set_ld_elf_hints_path(); 6065 rtld_printf( 6066 "FreeBSD ld-elf.so.1 %s\n" 6067 "FreeBSD_version %d\n" 6068 "Default lib path %s\n" 6069 "Hints lib path %s\n" 6070 "Env prefix %s\n" 6071 "Default hint file %s\n" 6072 "Hint file %s\n" 6073 "libmap file %s\n", 6074 machine, 6075 __FreeBSD_version, ld_standard_library_path, 6076 gethints(false), 6077 ld_env_prefix, ld_elf_hints_default, 6078 ld_elf_hints_path, 6079 ld_path_libmap_conf); 6080 _exit(0); 6081 } else { 6082 _rtld_error("Invalid argument: '%s'", arg); 6083 print_usage(argv[0]); 6084 rtld_die(); 6085 } 6086 } 6087 } 6088 6089 if (!seen_b) 6090 *argv0 = argv[i]; 6091 return (i); 6092 } 6093 6094 /* 6095 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 6096 */ 6097 static int 6098 parse_integer(const char *str) 6099 { 6100 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 6101 const char *orig; 6102 int n; 6103 char c; 6104 6105 orig = str; 6106 n = 0; 6107 for (c = *str; c != '\0'; c = *++str) { 6108 if (c < '0' || c > '9') 6109 return (-1); 6110 6111 n *= RADIX; 6112 n += c - '0'; 6113 } 6114 6115 /* Make sure we actually parsed something. */ 6116 if (str == orig) 6117 return (-1); 6118 return (n); 6119 } 6120 6121 static void 6122 print_usage(const char *argv0) 6123 { 6124 6125 rtld_printf( 6126 "Usage: %s [-h] [-b <exe>] [-d] [-f <FD>] [-p] [--] <binary> [<args>]\n" 6127 "\n" 6128 "Options:\n" 6129 " -h Display this help message\n" 6130 " -b <exe> Execute <exe> instead of <binary>, arg0 is <binary>\n" 6131 " -d Ignore lack of exec permissions for the binary\n" 6132 " -f <FD> Execute <FD> instead of searching for <binary>\n" 6133 " -p Search in PATH for named binary\n" 6134 " -u Ignore LD_ environment variables\n" 6135 " -v Display identification information\n" 6136 " -- End of RTLD options\n" 6137 " <binary> Name of process to execute\n" 6138 " <args> Arguments to the executed process\n", argv0); 6139 } 6140 6141 #define AUXFMT(at, xfmt) [at] = { .name = #at, .fmt = xfmt } 6142 static const struct auxfmt { 6143 const char *name; 6144 const char *fmt; 6145 } auxfmts[] = { 6146 AUXFMT(AT_NULL, NULL), 6147 AUXFMT(AT_IGNORE, NULL), 6148 AUXFMT(AT_EXECFD, "%ld"), 6149 AUXFMT(AT_PHDR, "%p"), 6150 AUXFMT(AT_PHENT, "%lu"), 6151 AUXFMT(AT_PHNUM, "%lu"), 6152 AUXFMT(AT_PAGESZ, "%lu"), 6153 AUXFMT(AT_BASE, "%#lx"), 6154 AUXFMT(AT_FLAGS, "%#lx"), 6155 AUXFMT(AT_ENTRY, "%p"), 6156 AUXFMT(AT_NOTELF, NULL), 6157 AUXFMT(AT_UID, "%ld"), 6158 AUXFMT(AT_EUID, "%ld"), 6159 AUXFMT(AT_GID, "%ld"), 6160 AUXFMT(AT_EGID, "%ld"), 6161 AUXFMT(AT_EXECPATH, "%s"), 6162 AUXFMT(AT_CANARY, "%p"), 6163 AUXFMT(AT_CANARYLEN, "%lu"), 6164 AUXFMT(AT_OSRELDATE, "%lu"), 6165 AUXFMT(AT_NCPUS, "%lu"), 6166 AUXFMT(AT_PAGESIZES, "%p"), 6167 AUXFMT(AT_PAGESIZESLEN, "%lu"), 6168 AUXFMT(AT_TIMEKEEP, "%p"), 6169 AUXFMT(AT_STACKPROT, "%#lx"), 6170 AUXFMT(AT_EHDRFLAGS, "%#lx"), 6171 AUXFMT(AT_HWCAP, "%#lx"), 6172 AUXFMT(AT_HWCAP2, "%#lx"), 6173 AUXFMT(AT_BSDFLAGS, "%#lx"), 6174 AUXFMT(AT_ARGC, "%lu"), 6175 AUXFMT(AT_ARGV, "%p"), 6176 AUXFMT(AT_ENVC, "%p"), 6177 AUXFMT(AT_ENVV, "%p"), 6178 AUXFMT(AT_PS_STRINGS, "%p"), 6179 AUXFMT(AT_FXRNG, "%p"), 6180 AUXFMT(AT_KPRELOAD, "%p"), 6181 }; 6182 6183 static bool 6184 is_ptr_fmt(const char *fmt) 6185 { 6186 char last; 6187 6188 last = fmt[strlen(fmt) - 1]; 6189 return (last == 'p' || last == 's'); 6190 } 6191 6192 static void 6193 dump_auxv(Elf_Auxinfo **aux_info) 6194 { 6195 Elf_Auxinfo *auxp; 6196 const struct auxfmt *fmt; 6197 int i; 6198 6199 for (i = 0; i < AT_COUNT; i++) { 6200 auxp = aux_info[i]; 6201 if (auxp == NULL) 6202 continue; 6203 fmt = &auxfmts[i]; 6204 if (fmt->fmt == NULL) 6205 continue; 6206 rtld_fdprintf(STDOUT_FILENO, "%s:\t", fmt->name); 6207 if (is_ptr_fmt(fmt->fmt)) { 6208 rtld_fdprintfx(STDOUT_FILENO, fmt->fmt, 6209 auxp->a_un.a_ptr); 6210 } else { 6211 rtld_fdprintfx(STDOUT_FILENO, fmt->fmt, 6212 auxp->a_un.a_val); 6213 } 6214 rtld_fdprintf(STDOUT_FILENO, "\n"); 6215 } 6216 } 6217 6218 /* 6219 * Overrides for libc_pic-provided functions. 6220 */ 6221 6222 int 6223 __getosreldate(void) 6224 { 6225 size_t len; 6226 int oid[2]; 6227 int error, osrel; 6228 6229 if (osreldate != 0) 6230 return (osreldate); 6231 6232 oid[0] = CTL_KERN; 6233 oid[1] = KERN_OSRELDATE; 6234 osrel = 0; 6235 len = sizeof(osrel); 6236 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 6237 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 6238 osreldate = osrel; 6239 return (osreldate); 6240 } 6241 const char * 6242 rtld_strerror(int errnum) 6243 { 6244 6245 if (errnum < 0 || errnum >= sys_nerr) 6246 return ("Unknown error"); 6247 return (sys_errlist[errnum]); 6248 } 6249 6250 char * 6251 getenv(const char *name) 6252 { 6253 return (__DECONST(char *, rtld_get_env_val(environ, name, 6254 strlen(name)))); 6255 } 6256 6257 /* malloc */ 6258 void * 6259 malloc(size_t nbytes) 6260 { 6261 6262 return (__crt_malloc(nbytes)); 6263 } 6264 6265 void * 6266 calloc(size_t num, size_t size) 6267 { 6268 6269 return (__crt_calloc(num, size)); 6270 } 6271 6272 void 6273 free(void *cp) 6274 { 6275 6276 __crt_free(cp); 6277 } 6278 6279 void * 6280 realloc(void *cp, size_t nbytes) 6281 { 6282 6283 return (__crt_realloc(cp, nbytes)); 6284 } 6285 6286 extern int _rtld_version__FreeBSD_version __exported; 6287 int _rtld_version__FreeBSD_version = __FreeBSD_version; 6288 6289 extern char _rtld_version_laddr_offset __exported; 6290 char _rtld_version_laddr_offset; 6291 6292 extern char _rtld_version_dlpi_tls_data __exported; 6293 char _rtld_version_dlpi_tls_data; 6294