1 /* Map in a shared object's segments from the file.
2 Copyright (C) 1995-2021 Free Software Foundation, Inc.
3 Copyright The GNU Toolchain Authors.
4 This file is part of the GNU C Library.
5
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
10
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
15
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, see
18 <https://www.gnu.org/licenses/>. */
19
20 #include <elf.h>
21 #include <errno.h>
22 #include <fcntl.h>
23 #include <libintl.h>
24 #include <stdbool.h>
25 #include <stdlib.h>
26 #include <string.h>
27 #include <unistd.h>
28 #include <ldsodefs.h>
29 #include <bits/wordsize.h>
30 #include <sys/mman.h>
31 #include <sys/param.h>
32 #include <sys/stat.h>
33 #include <sys/types.h>
34 #include <gnu/lib-names.h>
35
36 /* Type for the buffer we put the ELF header and hopefully the program
37 header. This buffer does not really have to be too large. In most
38 cases the program header follows the ELF header directly. If this
39 is not the case all bets are off and we can make the header
40 arbitrarily large and still won't get it read. This means the only
41 question is how large are the ELF and program header combined. The
42 ELF header 32-bit files is 52 bytes long and in 64-bit files is 64
43 bytes long. Each program header entry is again 32 and 56 bytes
44 long respectively. I.e., even with a file which has 10 program
45 header entries we only have to read 372B/624B respectively. Add to
46 this a bit of margin for program notes and reading 512B and 832B
47 for 32-bit and 64-bit files respecitvely is enough. If this
48 heuristic should really fail for some file the code in
49 `_dl_map_object_from_fd' knows how to recover. */
50 struct filebuf
51 {
52 ssize_t len;
53 #if __WORDSIZE == 32
54 # define FILEBUF_SIZE 512
55 #else
56 # define FILEBUF_SIZE 832
57 #endif
58 char buf[FILEBUF_SIZE] __attribute__ ((aligned (__alignof (ElfW(Ehdr)))));
59 };
60
61 #include "dynamic-link.h"
62 #include "get-dynamic-info.h"
63 #include <abi-tag.h>
64 #include <stackinfo.h>
65 #include <sysdep.h>
66 #include <stap-probe.h>
67 #include <libc-pointer-arith.h>
68 #include <array_length.h>
69
70 #include <dl-dst.h>
71 #include <dl-load.h>
72 #include <dl-map-segments.h>
73 #include <dl-unmap-segments.h>
74 #include <dl-machine-reject-phdr.h>
75 #include <dl-sysdep-open.h>
76 #include <dl-prop.h>
77 #include <not-cancel.h>
78
79 #include <endian.h>
80 #if BYTE_ORDER == BIG_ENDIAN
81 # define byteorder ELFDATA2MSB
82 #elif BYTE_ORDER == LITTLE_ENDIAN
83 # define byteorder ELFDATA2LSB
84 #else
85 # error "Unknown BYTE_ORDER " BYTE_ORDER
86 # define byteorder ELFDATANONE
87 #endif
88
89 #define STRING(x) __STRING (x)
90
91
92 int __stack_prot attribute_hidden attribute_relro
93 #if _STACK_GROWS_DOWN && defined PROT_GROWSDOWN
94 = PROT_GROWSDOWN;
95 #elif _STACK_GROWS_UP && defined PROT_GROWSUP
96 = PROT_GROWSUP;
97 #else
98 = 0;
99 #endif
100
101
102 /* This is the decomposed LD_LIBRARY_PATH search path. */
103 struct r_search_path_struct __rtld_env_path_list attribute_relro;
104
105 /* List of the hardware capabilities we might end up using. */
106 #ifdef SHARED
107 static const struct r_strlenpair *capstr attribute_relro;
108 static size_t ncapstr attribute_relro;
109 static size_t max_capstrlen attribute_relro;
110 #else
111 enum { ncapstr = 1, max_capstrlen = 0 };
112 #endif
113
114
115 /* Get the generated information about the trusted directories. Use
116 an array of concatenated strings to avoid relocations. See
117 gen-trusted-dirs.awk. */
118 #include "trusted-dirs.h"
119
120 static const char system_dirs[] = SYSTEM_DIRS;
121 static const size_t system_dirs_len[] =
122 {
123 SYSTEM_DIRS_LEN
124 };
125 #define nsystem_dirs_len array_length (system_dirs_len)
126
127 static bool
is_trusted_path_normalize(const char * path,size_t len)128 is_trusted_path_normalize (const char *path, size_t len)
129 {
130 if (len == 0)
131 return false;
132
133 char *npath = (char *) alloca (len + 2);
134 char *wnp = npath;
135 while (*path != '\0')
136 {
137 if (path[0] == '/')
138 {
139 if (path[1] == '.')
140 {
141 if (path[2] == '.' && (path[3] == '/' || path[3] == '\0'))
142 {
143 while (wnp > npath && *--wnp != '/')
144 ;
145 path += 3;
146 continue;
147 }
148 else if (path[2] == '/' || path[2] == '\0')
149 {
150 path += 2;
151 continue;
152 }
153 }
154
155 if (wnp > npath && wnp[-1] == '/')
156 {
157 ++path;
158 continue;
159 }
160 }
161
162 *wnp++ = *path++;
163 }
164
165 if (wnp == npath || wnp[-1] != '/')
166 *wnp++ = '/';
167
168 const char *trun = system_dirs;
169
170 for (size_t idx = 0; idx < nsystem_dirs_len; ++idx)
171 {
172 if (wnp - npath >= system_dirs_len[idx]
173 && memcmp (trun, npath, system_dirs_len[idx]) == 0)
174 /* Found it. */
175 return true;
176
177 trun += system_dirs_len[idx] + 1;
178 }
179
180 return false;
181 }
182
183 /* Given a substring starting at INPUT, just after the DST '$' start
184 token, determine if INPUT contains DST token REF, following the
185 ELF gABI rules for DSTs:
186
187 * Longest possible sequence using the rules (greedy).
188
189 * Must start with a $ (enforced by caller).
190
191 * Must follow $ with one underscore or ASCII [A-Za-z] (caller
192 follows these rules for REF) or '{' (start curly quoted name).
193
194 * Must follow first two characters with zero or more [A-Za-z0-9_]
195 (enforced by caller) or '}' (end curly quoted name).
196
197 If the sequence is a DST matching REF then the length of the DST
198 (excluding the $ sign but including curly braces, if any) is
199 returned, otherwise 0. */
200 static size_t
is_dst(const char * input,const char * ref)201 is_dst (const char *input, const char *ref)
202 {
203 bool is_curly = false;
204
205 /* Is a ${...} input sequence? */
206 if (input[0] == '{')
207 {
208 is_curly = true;
209 ++input;
210 }
211
212 /* Check for matching name, following closing curly brace (if
213 required), or trailing characters which are part of an
214 identifier. */
215 size_t rlen = strlen (ref);
216 if (strncmp (input, ref, rlen) != 0
217 || (is_curly && input[rlen] != '}')
218 || ((input[rlen] >= 'A' && input[rlen] <= 'Z')
219 || (input[rlen] >= 'a' && input[rlen] <= 'z')
220 || (input[rlen] >= '0' && input[rlen] <= '9')
221 || (input[rlen] == '_')))
222 return 0;
223
224 if (is_curly)
225 /* Count the two curly braces. */
226 return rlen + 2;
227 else
228 return rlen;
229 }
230
231 /* INPUT should be the start of a path e.g DT_RPATH or name e.g.
232 DT_NEEDED. The return value is the number of known DSTs found. We
233 count all known DSTs regardless of __libc_enable_secure; the caller
234 is responsible for enforcing the security of the substitution rules
235 (usually _dl_dst_substitute). */
236 size_t
_dl_dst_count(const char * input)237 _dl_dst_count (const char *input)
238 {
239 size_t cnt = 0;
240
241 input = strchr (input, '$');
242
243 /* Most likely there is no DST. */
244 if (__glibc_likely (input == NULL))
245 return 0;
246
247 do
248 {
249 size_t len;
250
251 ++input;
252 /* All DSTs must follow ELF gABI rules, see is_dst (). */
253 if ((len = is_dst (input, "ORIGIN")) != 0
254 || (len = is_dst (input, "PLATFORM")) != 0
255 || (len = is_dst (input, "LIB")) != 0)
256 ++cnt;
257
258 /* There may be more than one DST in the input. */
259 input = strchr (input + len, '$');
260 }
261 while (input != NULL);
262
263 return cnt;
264 }
265
266 /* Process INPUT for DSTs and store in RESULT using the information
267 from link map L to resolve the DSTs. This function only handles one
268 path at a time and does not handle colon-separated path lists (see
269 fillin_rpath ()). Lastly the size of result in bytes should be at
270 least equal to the value returned by DL_DST_REQUIRED. Note that it
271 is possible for a DT_NEEDED, DT_AUXILIARY, and DT_FILTER entries to
272 have colons, but we treat those as literal colons here, not as path
273 list delimeters. */
274 char *
_dl_dst_substitute(struct link_map * l,const char * input,char * result)275 _dl_dst_substitute (struct link_map *l, const char *input, char *result)
276 {
277 /* Copy character-by-character from input into the working pointer
278 looking for any DSTs. We track the start of input and if we are
279 going to check for trusted paths, all of which are part of $ORIGIN
280 handling in SUID/SGID cases (see below). In some cases, like when
281 a DST cannot be replaced, we may set result to an empty string and
282 return. */
283 char *wp = result;
284 const char *start = input;
285 bool check_for_trusted = false;
286
287 do
288 {
289 if (__glibc_unlikely (*input == '$'))
290 {
291 const char *repl = NULL;
292 size_t len;
293
294 ++input;
295 if ((len = is_dst (input, "ORIGIN")) != 0)
296 {
297 /* For SUID/GUID programs we normally ignore the path with
298 $ORIGIN in DT_RUNPATH, or DT_RPATH. However, there is
299 one exception to this rule, and it is:
300
301 * $ORIGIN appears as the first path element, and is
302 the only string in the path or is immediately
303 followed by a path separator and the rest of the
304 path,
305
306 and ...
307
308 * The path is rooted in a trusted directory.
309
310 This exception allows such programs to reference
311 shared libraries in subdirectories of trusted
312 directories. The use case is one of general
313 organization and deployment flexibility.
314 Trusted directories are usually such paths as "/lib64"
315 or "/usr/lib64", and the usual RPATHs take the form of
316 [$ORIGIN/../$LIB/somedir]. */
317 if (__glibc_unlikely (__libc_enable_secure)
318 && !(input == start + 1
319 && (input[len] == '\0' || input[len] == '/')))
320 repl = (const char *) -1;
321 else
322 repl = l->l_origin;
323
324 check_for_trusted = (__libc_enable_secure
325 && l->l_type == lt_executable);
326 }
327 else if ((len = is_dst (input, "PLATFORM")) != 0)
328 repl = GLRO(dl_platform);
329 else if ((len = is_dst (input, "LIB")) != 0)
330 repl = DL_DST_LIB;
331
332 if (repl != NULL && repl != (const char *) -1)
333 {
334 wp = __stpcpy (wp, repl);
335 input += len;
336 }
337 else if (len != 0)
338 {
339 /* We found a valid DST that we know about, but we could
340 not find a replacement value for it, therefore we
341 cannot use this path and discard it. */
342 *result = '\0';
343 return result;
344 }
345 else
346 /* No DST we recognize. */
347 *wp++ = '$';
348 }
349 else
350 {
351 *wp++ = *input++;
352 }
353 }
354 while (*input != '\0');
355
356 /* In SUID/SGID programs, after $ORIGIN expansion the normalized
357 path must be rooted in one of the trusted directories. The $LIB
358 and $PLATFORM DST cannot in any way be manipulated by the caller
359 because they are fixed values that are set by the dynamic loader
360 and therefore any paths using just $LIB or $PLATFORM need not be
361 checked for trust, the authors of the binaries themselves are
362 trusted to have designed this correctly. Only $ORIGIN is tested in
363 this way because it may be manipulated in some ways with hard
364 links. */
365 if (__glibc_unlikely (check_for_trusted)
366 && !is_trusted_path_normalize (result, wp - result))
367 {
368 *result = '\0';
369 return result;
370 }
371
372 *wp = '\0';
373
374 return result;
375 }
376
377
378 /* Return a malloc allocated copy of INPUT with all recognized DSTs
379 replaced. On some platforms it might not be possible to determine the
380 path from which the object belonging to the map is loaded. In this
381 case the path containing the DST is left out. On error NULL
382 is returned. */
383 static char *
expand_dynamic_string_token(struct link_map * l,const char * input)384 expand_dynamic_string_token (struct link_map *l, const char *input)
385 {
386 /* We make two runs over the string. First we determine how large the
387 resulting string is and then we copy it over. Since this is no
388 frequently executed operation we are looking here not for performance
389 but rather for code size. */
390 size_t cnt;
391 size_t total;
392 char *result;
393
394 /* Determine the number of DSTs. */
395 cnt = _dl_dst_count (input);
396
397 /* If we do not have to replace anything simply copy the string. */
398 if (__glibc_likely (cnt == 0))
399 return __strdup (input);
400
401 /* Determine the length of the substituted string. */
402 total = DL_DST_REQUIRED (l, input, strlen (input), cnt);
403
404 /* Allocate the necessary memory. */
405 result = (char *) malloc (total + 1);
406 if (result == NULL)
407 return NULL;
408
409 return _dl_dst_substitute (l, input, result);
410 }
411
412
413 /* Add `name' to the list of names for a particular shared object.
414 `name' is expected to have been allocated with malloc and will
415 be freed if the shared object already has this name.
416 Returns false if the object already had this name. */
417 static void
add_name_to_object(struct link_map * l,const char * name)418 add_name_to_object (struct link_map *l, const char *name)
419 {
420 struct libname_list *lnp, *lastp;
421 struct libname_list *newname;
422 size_t name_len;
423
424 lastp = NULL;
425 for (lnp = l->l_libname; lnp != NULL; lastp = lnp, lnp = lnp->next)
426 if (strcmp (name, lnp->name) == 0)
427 return;
428
429 name_len = strlen (name) + 1;
430 newname = (struct libname_list *) malloc (sizeof *newname + name_len);
431 if (newname == NULL)
432 {
433 /* No more memory. */
434 _dl_signal_error (ENOMEM, name, NULL, N_("cannot allocate name record"));
435 return;
436 }
437 /* The object should have a libname set from _dl_new_object. */
438 assert (lastp != NULL);
439
440 newname->name = memcpy (newname + 1, name, name_len);
441 newname->next = NULL;
442 newname->dont_free = 0;
443 /* CONCURRENCY NOTES:
444
445 Make sure the initialization of newname happens before its address is
446 read from the lastp->next store below.
447
448 GL(dl_load_lock) is held here (and by other writers, e.g. dlclose), so
449 readers of libname_list->next (e.g. _dl_check_caller or the reads above)
450 can use that for synchronization, however the read in _dl_name_match_p
451 may be executed without holding the lock during _dl_runtime_resolve
452 (i.e. lazy symbol resolution when a function of library l is called).
453
454 The release MO store below synchronizes with the acquire MO load in
455 _dl_name_match_p. Other writes need to synchronize with that load too,
456 however those happen either early when the process is single threaded
457 (dl_main) or when the library is unloaded (dlclose) and the user has to
458 synchronize library calls with unloading. */
459 atomic_store_release (&lastp->next, newname);
460 }
461
462 /* Standard search directories. */
463 struct r_search_path_struct __rtld_search_dirs attribute_relro;
464
465 static size_t max_dirnamelen;
466
467 static struct r_search_path_elem **
fillin_rpath(char * rpath,struct r_search_path_elem ** result,const char * sep,const char * what,const char * where,struct link_map * l)468 fillin_rpath (char *rpath, struct r_search_path_elem **result, const char *sep,
469 const char *what, const char *where, struct link_map *l)
470 {
471 char *cp;
472 size_t nelems = 0;
473
474 while ((cp = __strsep (&rpath, sep)) != NULL)
475 {
476 struct r_search_path_elem *dirp;
477 char *to_free = NULL;
478 size_t len = 0;
479
480 /* `strsep' can pass an empty string. */
481 if (*cp != '\0')
482 {
483 to_free = cp = expand_dynamic_string_token (l, cp);
484
485 /* expand_dynamic_string_token can return NULL in case of empty
486 path or memory allocation failure. */
487 if (cp == NULL)
488 continue;
489
490 /* Compute the length after dynamic string token expansion and
491 ignore empty paths. */
492 len = strlen (cp);
493 if (len == 0)
494 {
495 free (to_free);
496 continue;
497 }
498
499 /* Remove trailing slashes (except for "/"). */
500 while (len > 1 && cp[len - 1] == '/')
501 --len;
502
503 /* Now add one if there is none so far. */
504 if (len > 0 && cp[len - 1] != '/')
505 cp[len++] = '/';
506 }
507
508 /* See if this directory is already known. */
509 for (dirp = GL(dl_all_dirs); dirp != NULL; dirp = dirp->next)
510 if (dirp->dirnamelen == len && memcmp (cp, dirp->dirname, len) == 0)
511 break;
512
513 if (dirp != NULL)
514 {
515 /* It is available, see whether it's on our own list. */
516 size_t cnt;
517 for (cnt = 0; cnt < nelems; ++cnt)
518 if (result[cnt] == dirp)
519 break;
520
521 if (cnt == nelems)
522 result[nelems++] = dirp;
523 }
524 else
525 {
526 size_t cnt;
527 enum r_dir_status init_val;
528 size_t where_len = where ? strlen (where) + 1 : 0;
529
530 /* It's a new directory. Create an entry and add it. */
531 dirp = (struct r_search_path_elem *)
532 malloc (sizeof (*dirp) + ncapstr * sizeof (enum r_dir_status)
533 + where_len + len + 1);
534 if (dirp == NULL)
535 _dl_signal_error (ENOMEM, NULL, NULL,
536 N_("cannot create cache for search path"));
537
538 dirp->dirname = ((char *) dirp + sizeof (*dirp)
539 + ncapstr * sizeof (enum r_dir_status));
540 *((char *) __mempcpy ((char *) dirp->dirname, cp, len)) = '\0';
541 dirp->dirnamelen = len;
542
543 if (len > max_dirnamelen)
544 max_dirnamelen = len;
545
546 /* We have to make sure all the relative directories are
547 never ignored. The current directory might change and
548 all our saved information would be void. */
549 init_val = cp[0] != '/' ? existing : unknown;
550 for (cnt = 0; cnt < ncapstr; ++cnt)
551 dirp->status[cnt] = init_val;
552
553 dirp->what = what;
554 if (__glibc_likely (where != NULL))
555 dirp->where = memcpy ((char *) dirp + sizeof (*dirp) + len + 1
556 + (ncapstr * sizeof (enum r_dir_status)),
557 where, where_len);
558 else
559 dirp->where = NULL;
560
561 dirp->next = GL(dl_all_dirs);
562 GL(dl_all_dirs) = dirp;
563
564 /* Put it in the result array. */
565 result[nelems++] = dirp;
566 }
567 free (to_free);
568 }
569
570 /* Terminate the array. */
571 result[nelems] = NULL;
572
573 return result;
574 }
575
576
577 static bool
decompose_rpath(struct r_search_path_struct * sps,const char * rpath,struct link_map * l,const char * what)578 decompose_rpath (struct r_search_path_struct *sps,
579 const char *rpath, struct link_map *l, const char *what)
580 {
581 /* Make a copy we can work with. */
582 const char *where = l->l_name;
583 char *cp;
584 struct r_search_path_elem **result;
585 size_t nelems;
586 /* Initialize to please the compiler. */
587 const char *errstring = NULL;
588
589 /* First see whether we must forget the RUNPATH and RPATH from this
590 object. */
591 if (__glibc_unlikely (GLRO(dl_inhibit_rpath) != NULL)
592 && !__libc_enable_secure)
593 {
594 const char *inhp = GLRO(dl_inhibit_rpath);
595
596 do
597 {
598 const char *wp = where;
599
600 while (*inhp == *wp && *wp != '\0')
601 {
602 ++inhp;
603 ++wp;
604 }
605
606 if (*wp == '\0' && (*inhp == '\0' || *inhp == ':'))
607 {
608 /* This object is on the list of objects for which the
609 RUNPATH and RPATH must not be used. */
610 sps->dirs = (void *) -1;
611 return false;
612 }
613
614 while (*inhp != '\0')
615 if (*inhp++ == ':')
616 break;
617 }
618 while (*inhp != '\0');
619 }
620
621 /* Ignore empty rpaths. */
622 if (*rpath == '\0')
623 {
624 sps->dirs = (struct r_search_path_elem **) -1;
625 return false;
626 }
627
628 /* Make a writable copy. */
629 char *copy = __strdup (rpath);
630 if (copy == NULL)
631 {
632 errstring = N_("cannot create RUNPATH/RPATH copy");
633 goto signal_error;
634 }
635
636 /* Count the number of necessary elements in the result array. */
637 nelems = 0;
638 for (cp = copy; *cp != '\0'; ++cp)
639 if (*cp == ':')
640 ++nelems;
641
642 /* Allocate room for the result. NELEMS + 1 is an upper limit for the
643 number of necessary entries. */
644 result = (struct r_search_path_elem **) malloc ((nelems + 1 + 1)
645 * sizeof (*result));
646 if (result == NULL)
647 {
648 free (copy);
649 errstring = N_("cannot create cache for search path");
650 signal_error:
651 _dl_signal_error (ENOMEM, NULL, NULL, errstring);
652 }
653
654 fillin_rpath (copy, result, ":", what, where, l);
655
656 /* Free the copied RPATH string. `fillin_rpath' make own copies if
657 necessary. */
658 free (copy);
659
660 /* There is no path after expansion. */
661 if (result[0] == NULL)
662 {
663 free (result);
664 sps->dirs = (struct r_search_path_elem **) -1;
665 return false;
666 }
667
668 sps->dirs = result;
669 /* The caller will change this value if we haven't used a real malloc. */
670 sps->malloced = 1;
671 return true;
672 }
673
674 /* Make sure cached path information is stored in *SP
675 and return true if there are any paths to search there. */
676 static bool
cache_rpath(struct link_map * l,struct r_search_path_struct * sp,int tag,const char * what)677 cache_rpath (struct link_map *l,
678 struct r_search_path_struct *sp,
679 int tag,
680 const char *what)
681 {
682 if (sp->dirs == (void *) -1)
683 return false;
684
685 if (sp->dirs != NULL)
686 return true;
687
688 if (l->l_info[tag] == NULL)
689 {
690 /* There is no path. */
691 sp->dirs = (void *) -1;
692 return false;
693 }
694
695 /* Make sure the cache information is available. */
696 return decompose_rpath (sp, (const char *) (D_PTR (l, l_info[DT_STRTAB])
697 + l->l_info[tag]->d_un.d_val),
698 l, what);
699 }
700
701
702 void
_dl_init_paths(const char * llp,const char * source,const char * glibc_hwcaps_prepend,const char * glibc_hwcaps_mask)703 _dl_init_paths (const char *llp, const char *source,
704 const char *glibc_hwcaps_prepend,
705 const char *glibc_hwcaps_mask)
706 {
707 size_t idx;
708 const char *strp;
709 struct r_search_path_elem *pelem, **aelem;
710 size_t round_size;
711 struct link_map __attribute__ ((unused)) *l = NULL;
712 /* Initialize to please the compiler. */
713 const char *errstring = NULL;
714
715 /* Fill in the information about the application's RPATH and the
716 directories addressed by the LD_LIBRARY_PATH environment variable. */
717
718 #ifdef SHARED
719 /* Get the capabilities. */
720 capstr = _dl_important_hwcaps (glibc_hwcaps_prepend, glibc_hwcaps_mask,
721 &ncapstr, &max_capstrlen);
722 #endif
723
724 /* First set up the rest of the default search directory entries. */
725 aelem = __rtld_search_dirs.dirs = (struct r_search_path_elem **)
726 malloc ((nsystem_dirs_len + 1) * sizeof (struct r_search_path_elem *));
727 if (__rtld_search_dirs.dirs == NULL)
728 {
729 errstring = N_("cannot create search path array");
730 signal_error:
731 _dl_signal_error (ENOMEM, NULL, NULL, errstring);
732 }
733
734 round_size = ((2 * sizeof (struct r_search_path_elem) - 1
735 + ncapstr * sizeof (enum r_dir_status))
736 / sizeof (struct r_search_path_elem));
737
738 __rtld_search_dirs.dirs[0]
739 = malloc (nsystem_dirs_len * round_size
740 * sizeof (*__rtld_search_dirs.dirs[0]));
741 if (__rtld_search_dirs.dirs[0] == NULL)
742 {
743 errstring = N_("cannot create cache for search path");
744 goto signal_error;
745 }
746
747 __rtld_search_dirs.malloced = 0;
748 pelem = GL(dl_all_dirs) = __rtld_search_dirs.dirs[0];
749 strp = system_dirs;
750 idx = 0;
751
752 do
753 {
754 size_t cnt;
755
756 *aelem++ = pelem;
757
758 pelem->what = "system search path";
759 pelem->where = NULL;
760
761 pelem->dirname = strp;
762 pelem->dirnamelen = system_dirs_len[idx];
763 strp += system_dirs_len[idx] + 1;
764
765 /* System paths must be absolute. */
766 assert (pelem->dirname[0] == '/');
767 for (cnt = 0; cnt < ncapstr; ++cnt)
768 pelem->status[cnt] = unknown;
769
770 pelem->next = (++idx == nsystem_dirs_len ? NULL : (pelem + round_size));
771
772 pelem += round_size;
773 }
774 while (idx < nsystem_dirs_len);
775
776 max_dirnamelen = SYSTEM_DIRS_MAX_LEN;
777 *aelem = NULL;
778
779 /* This points to the map of the main object. If there is no main
780 object (e.g., under --help, use the dynamic loader itself as a
781 stand-in. */
782 l = GL(dl_ns)[LM_ID_BASE]._ns_loaded;
783 #ifdef SHARED
784 if (l == NULL)
785 l = &GL (dl_rtld_map);
786 #endif
787 assert (l->l_type != lt_loaded);
788
789 if (l->l_info[DT_RUNPATH])
790 {
791 /* Allocate room for the search path and fill in information
792 from RUNPATH. */
793 decompose_rpath (&l->l_runpath_dirs,
794 (const void *) (D_PTR (l, l_info[DT_STRTAB])
795 + l->l_info[DT_RUNPATH]->d_un.d_val),
796 l, "RUNPATH");
797 /* During rtld init the memory is allocated by the stub malloc,
798 prevent any attempt to free it by the normal malloc. */
799 l->l_runpath_dirs.malloced = 0;
800
801 /* The RPATH is ignored. */
802 l->l_rpath_dirs.dirs = (void *) -1;
803 }
804 else
805 {
806 l->l_runpath_dirs.dirs = (void *) -1;
807
808 if (l->l_info[DT_RPATH])
809 {
810 /* Allocate room for the search path and fill in information
811 from RPATH. */
812 decompose_rpath (&l->l_rpath_dirs,
813 (const void *) (D_PTR (l, l_info[DT_STRTAB])
814 + l->l_info[DT_RPATH]->d_un.d_val),
815 l, "RPATH");
816 /* During rtld init the memory is allocated by the stub
817 malloc, prevent any attempt to free it by the normal
818 malloc. */
819 l->l_rpath_dirs.malloced = 0;
820 }
821 else
822 l->l_rpath_dirs.dirs = (void *) -1;
823 }
824
825 if (llp != NULL && *llp != '\0')
826 {
827 char *llp_tmp = strdupa (llp);
828
829 /* Decompose the LD_LIBRARY_PATH contents. First determine how many
830 elements it has. */
831 size_t nllp = 1;
832 for (const char *cp = llp_tmp; *cp != '\0'; ++cp)
833 if (*cp == ':' || *cp == ';')
834 ++nllp;
835
836 __rtld_env_path_list.dirs = (struct r_search_path_elem **)
837 malloc ((nllp + 1) * sizeof (struct r_search_path_elem *));
838 if (__rtld_env_path_list.dirs == NULL)
839 {
840 errstring = N_("cannot create cache for search path");
841 goto signal_error;
842 }
843
844 (void) fillin_rpath (llp_tmp, __rtld_env_path_list.dirs, ":;",
845 source, NULL, l);
846
847 if (__rtld_env_path_list.dirs[0] == NULL)
848 {
849 free (__rtld_env_path_list.dirs);
850 __rtld_env_path_list.dirs = (void *) -1;
851 }
852
853 __rtld_env_path_list.malloced = 0;
854 }
855 else
856 __rtld_env_path_list.dirs = (void *) -1;
857 }
858
859
860 /* Process PT_GNU_PROPERTY program header PH in module L after
861 PT_LOAD segments are mapped. Only one NT_GNU_PROPERTY_TYPE_0
862 note is handled which contains processor specific properties.
863 FD is -1 for the kernel mapped main executable otherwise it is
864 the fd used for loading module L. */
865
866 void
_dl_process_pt_gnu_property(struct link_map * l,int fd,const ElfW (Phdr)* ph)867 _dl_process_pt_gnu_property (struct link_map *l, int fd, const ElfW(Phdr) *ph)
868 {
869 const ElfW(Nhdr) *note = (const void *) (ph->p_vaddr + l->l_addr);
870 const ElfW(Addr) size = ph->p_memsz;
871 const ElfW(Addr) align = ph->p_align;
872
873 /* The NT_GNU_PROPERTY_TYPE_0 note must be aligned to 4 bytes in
874 32-bit objects and to 8 bytes in 64-bit objects. Skip notes
875 with incorrect alignment. */
876 if (align != (__ELF_NATIVE_CLASS / 8))
877 return;
878
879 const ElfW(Addr) start = (ElfW(Addr)) note;
880 unsigned int last_type = 0;
881
882 while ((ElfW(Addr)) (note + 1) - start < size)
883 {
884 /* Find the NT_GNU_PROPERTY_TYPE_0 note. */
885 if (note->n_namesz == 4
886 && note->n_type == NT_GNU_PROPERTY_TYPE_0
887 && memcmp (note + 1, "GNU", 4) == 0)
888 {
889 /* Check for invalid property. */
890 if (note->n_descsz < 8
891 || (note->n_descsz % sizeof (ElfW(Addr))) != 0)
892 return;
893
894 /* Start and end of property array. */
895 unsigned char *ptr = (unsigned char *) (note + 1) + 4;
896 unsigned char *ptr_end = ptr + note->n_descsz;
897
898 do
899 {
900 unsigned int type = *(unsigned int *) ptr;
901 unsigned int datasz = *(unsigned int *) (ptr + 4);
902
903 /* Property type must be in ascending order. */
904 if (type < last_type)
905 return;
906
907 ptr += 8;
908 if ((ptr + datasz) > ptr_end)
909 return;
910
911 last_type = type;
912
913 /* Target specific property processing. */
914 if (_dl_process_gnu_property (l, fd, type, datasz, ptr) == 0)
915 return;
916
917 /* Check the next property item. */
918 ptr += ALIGN_UP (datasz, sizeof (ElfW(Addr)));
919 }
920 while ((ptr_end - ptr) >= 8);
921
922 /* Only handle one NT_GNU_PROPERTY_TYPE_0. */
923 return;
924 }
925
926 note = ((const void *) note
927 + ELF_NOTE_NEXT_OFFSET (note->n_namesz, note->n_descsz,
928 align));
929 }
930 }
931
932
933 /* Map in the shared object NAME, actually located in REALNAME, and already
934 opened on FD. */
935
936 #ifndef EXTERNAL_MAP_FROM_FD
937 static
938 #endif
939 struct link_map *
_dl_map_object_from_fd(const char * name,const char * origname,int fd,struct filebuf * fbp,char * realname,struct link_map * loader,int l_type,int mode,void ** stack_endp,Lmid_t nsid)940 _dl_map_object_from_fd (const char *name, const char *origname, int fd,
941 struct filebuf *fbp, char *realname,
942 struct link_map *loader, int l_type, int mode,
943 void **stack_endp, Lmid_t nsid)
944 {
945 struct link_map *l = NULL;
946 const ElfW(Ehdr) *header;
947 const ElfW(Phdr) *phdr;
948 const ElfW(Phdr) *ph;
949 size_t maplength;
950 int type;
951 /* Initialize to keep the compiler happy. */
952 const char *errstring = NULL;
953 int errval = 0;
954 struct r_debug *r = _dl_debug_update (nsid);
955 bool make_consistent = false;
956
957 /* Get file information. To match the kernel behavior, do not fill
958 in this information for the executable in case of an explicit
959 loader invocation. */
960 struct r_file_id id;
961 if (mode & __RTLD_OPENEXEC)
962 {
963 assert (nsid == LM_ID_BASE);
964 memset (&id, 0, sizeof (id));
965 }
966 else
967 {
968 if (__glibc_unlikely (!_dl_get_file_id (fd, &id)))
969 {
970 errstring = N_("cannot stat shared object");
971 lose_errno:
972 errval = errno;
973 lose:
974 /* The file might already be closed. */
975 if (fd != -1)
976 __close_nocancel (fd);
977 if (l != NULL && l->l_map_start != 0)
978 _dl_unmap_segments (l);
979 if (l != NULL && l->l_origin != (char *) -1l)
980 free ((char *) l->l_origin);
981 if (l != NULL && !l->l_libname->dont_free)
982 free (l->l_libname);
983 if (l != NULL && l->l_phdr_allocated)
984 free ((void *) l->l_phdr);
985 free (l);
986 free (realname);
987
988 if (make_consistent && r != NULL)
989 {
990 r->r_state = RT_CONSISTENT;
991 _dl_debug_state ();
992 LIBC_PROBE (map_failed, 2, nsid, r);
993 }
994
995 _dl_signal_error (errval, name, NULL, errstring);
996 }
997
998 /* Look again to see if the real name matched another already loaded. */
999 for (l = GL(dl_ns)[nsid]._ns_loaded; l != NULL; l = l->l_next)
1000 if (!l->l_removed && _dl_file_id_match_p (&l->l_file_id, &id))
1001 {
1002 /* The object is already loaded.
1003 Just bump its reference count and return it. */
1004 __close_nocancel (fd);
1005
1006 /* If the name is not in the list of names for this object add
1007 it. */
1008 free (realname);
1009 add_name_to_object (l, name);
1010
1011 return l;
1012 }
1013 }
1014
1015 #ifdef SHARED
1016 /* When loading into a namespace other than the base one we must
1017 avoid loading ld.so since there can only be one copy. Ever. */
1018 if (__glibc_unlikely (nsid != LM_ID_BASE)
1019 && (_dl_file_id_match_p (&id, &GL(dl_rtld_map).l_file_id)
1020 || _dl_name_match_p (name, &GL(dl_rtld_map))))
1021 {
1022 /* This is indeed ld.so. Create a new link_map which refers to
1023 the real one for almost everything. */
1024 l = _dl_new_object (realname, name, l_type, loader, mode, nsid);
1025 if (l == NULL)
1026 goto fail_new;
1027
1028 /* Refer to the real descriptor. */
1029 l->l_real = &GL(dl_rtld_map);
1030
1031 /* Copy l_addr and l_ld to avoid a GDB warning with dlmopen(). */
1032 l->l_addr = l->l_real->l_addr;
1033 l->l_ld = l->l_real->l_ld;
1034
1035 /* No need to bump the refcount of the real object, ld.so will
1036 never be unloaded. */
1037 __close_nocancel (fd);
1038
1039 /* Add the map for the mirrored object to the object list. */
1040 _dl_add_to_namespace_list (l, nsid);
1041
1042 return l;
1043 }
1044 #endif
1045
1046 if (mode & RTLD_NOLOAD)
1047 {
1048 /* We are not supposed to load the object unless it is already
1049 loaded. So return now. */
1050 free (realname);
1051 __close_nocancel (fd);
1052 return NULL;
1053 }
1054
1055 /* Print debugging message. */
1056 if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_FILES))
1057 _dl_debug_printf ("file=%s [%lu]; generating link map\n", name, nsid);
1058
1059 /* This is the ELF header. We read it in `open_verify'. */
1060 header = (void *) fbp->buf;
1061
1062 /* Enter the new object in the list of loaded objects. */
1063 l = _dl_new_object (realname, name, l_type, loader, mode, nsid);
1064 if (__glibc_unlikely (l == NULL))
1065 {
1066 #ifdef SHARED
1067 fail_new:
1068 #endif
1069 errstring = N_("cannot create shared object descriptor");
1070 goto lose_errno;
1071 }
1072
1073 /* Extract the remaining details we need from the ELF header
1074 and then read in the program header table. */
1075 l->l_entry = header->e_entry;
1076 type = header->e_type;
1077 l->l_phnum = header->e_phnum;
1078
1079 maplength = header->e_phnum * sizeof (ElfW(Phdr));
1080 if (header->e_phoff + maplength <= (size_t) fbp->len)
1081 phdr = (void *) (fbp->buf + header->e_phoff);
1082 else
1083 {
1084 phdr = alloca (maplength);
1085 if ((size_t) __pread64_nocancel (fd, (void *) phdr, maplength,
1086 header->e_phoff) != maplength)
1087 {
1088 errstring = N_("cannot read file data");
1089 goto lose_errno;
1090 }
1091 }
1092
1093 /* On most platforms presume that PT_GNU_STACK is absent and the stack is
1094 * executable. Other platforms default to a nonexecutable stack and don't
1095 * need PT_GNU_STACK to do so. */
1096 uint_fast16_t stack_flags = DEFAULT_STACK_PERMS;
1097
1098 {
1099 /* Scan the program header table, collecting its load commands. */
1100 struct loadcmd loadcmds[l->l_phnum];
1101 size_t nloadcmds = 0;
1102 bool has_holes = false;
1103 bool empty_dynamic = false;
1104
1105 /* The struct is initialized to zero so this is not necessary:
1106 l->l_ld = 0;
1107 l->l_phdr = 0;
1108 l->l_addr = 0; */
1109 for (ph = phdr; ph < &phdr[l->l_phnum]; ++ph)
1110 switch (ph->p_type)
1111 {
1112 /* These entries tell us where to find things once the file's
1113 segments are mapped in. We record the addresses it says
1114 verbatim, and later correct for the run-time load address. */
1115 case PT_DYNAMIC:
1116 if (ph->p_filesz == 0)
1117 empty_dynamic = true; /* Usually separate debuginfo. */
1118 else
1119 {
1120 /* Debuginfo only files from "objcopy --only-keep-debug"
1121 contain a PT_DYNAMIC segment with p_filesz == 0. Skip
1122 such a segment to avoid a crash later. */
1123 l->l_ld = (void *) ph->p_vaddr;
1124 l->l_ldnum = ph->p_memsz / sizeof (ElfW(Dyn));
1125 l->l_ld_readonly = (ph->p_flags & PF_W) == 0;
1126 }
1127 break;
1128
1129 case PT_PHDR:
1130 l->l_phdr = (void *) ph->p_vaddr;
1131 break;
1132
1133 case PT_LOAD:
1134 /* A load command tells us to map in part of the file.
1135 We record the load commands and process them all later. */
1136 if (__glibc_unlikely (((ph->p_vaddr - ph->p_offset)
1137 & (GLRO(dl_pagesize) - 1)) != 0))
1138 {
1139 errstring
1140 = N_("ELF load command address/offset not page-aligned");
1141 goto lose;
1142 }
1143
1144 struct loadcmd *c = &loadcmds[nloadcmds++];
1145 c->mapstart = ALIGN_DOWN (ph->p_vaddr, GLRO(dl_pagesize));
1146 c->mapend = ALIGN_UP (ph->p_vaddr + ph->p_filesz, GLRO(dl_pagesize));
1147 c->dataend = ph->p_vaddr + ph->p_filesz;
1148 c->allocend = ph->p_vaddr + ph->p_memsz;
1149 c->mapalign = ph->p_align;
1150 c->mapoff = ALIGN_DOWN (ph->p_offset, GLRO(dl_pagesize));
1151
1152 /* Determine whether there is a gap between the last segment
1153 and this one. */
1154 if (nloadcmds > 1 && c[-1].mapend != c->mapstart)
1155 has_holes = true;
1156
1157 /* Optimize a common case. */
1158 #if (PF_R | PF_W | PF_X) == 7 && (PROT_READ | PROT_WRITE | PROT_EXEC) == 7
1159 c->prot = (PF_TO_PROT
1160 >> ((ph->p_flags & (PF_R | PF_W | PF_X)) * 4)) & 0xf;
1161 #else
1162 c->prot = 0;
1163 if (ph->p_flags & PF_R)
1164 c->prot |= PROT_READ;
1165 if (ph->p_flags & PF_W)
1166 c->prot |= PROT_WRITE;
1167 if (ph->p_flags & PF_X)
1168 c->prot |= PROT_EXEC;
1169 #endif
1170 break;
1171
1172 case PT_TLS:
1173 if (ph->p_memsz == 0)
1174 /* Nothing to do for an empty segment. */
1175 break;
1176
1177 l->l_tls_blocksize = ph->p_memsz;
1178 l->l_tls_align = ph->p_align;
1179 if (ph->p_align == 0)
1180 l->l_tls_firstbyte_offset = 0;
1181 else
1182 l->l_tls_firstbyte_offset = ph->p_vaddr & (ph->p_align - 1);
1183 l->l_tls_initimage_size = ph->p_filesz;
1184 /* Since we don't know the load address yet only store the
1185 offset. We will adjust it later. */
1186 l->l_tls_initimage = (void *) ph->p_vaddr;
1187
1188 /* l->l_tls_modid is assigned below, once there is no
1189 possibility for failure. */
1190
1191 if (l->l_type != lt_library
1192 && GL(dl_tls_dtv_slotinfo_list) == NULL)
1193 {
1194 #ifdef SHARED
1195 /* We are loading the executable itself when the dynamic
1196 linker was executed directly. The setup will happen
1197 later. */
1198 assert (l->l_prev == NULL || (mode & __RTLD_AUDIT) != 0);
1199 #else
1200 assert (false && "TLS not initialized in static application");
1201 #endif
1202 }
1203 break;
1204
1205 case PT_GNU_STACK:
1206 stack_flags = ph->p_flags;
1207 break;
1208
1209 case PT_GNU_RELRO:
1210 l->l_relro_addr = ph->p_vaddr;
1211 l->l_relro_size = ph->p_memsz;
1212 break;
1213 }
1214
1215 if (__glibc_unlikely (nloadcmds == 0))
1216 {
1217 /* This only happens for a bogus object that will be caught with
1218 another error below. But we don't want to go through the
1219 calculations below using NLOADCMDS - 1. */
1220 errstring = N_("object file has no loadable segments");
1221 goto lose;
1222 }
1223
1224 /* dlopen of an executable is not valid because it is not possible
1225 to perform proper relocations, handle static TLS, or run the
1226 ELF constructors. For PIE, the check needs the dynamic
1227 section, so there is another check below. */
1228 if (__glibc_unlikely (type != ET_DYN)
1229 && __glibc_unlikely ((mode & __RTLD_OPENEXEC) == 0))
1230 {
1231 /* This object is loaded at a fixed address. This must never
1232 happen for objects loaded with dlopen. */
1233 errstring = N_("cannot dynamically load executable");
1234 goto lose;
1235 }
1236
1237 /* This check recognizes most separate debuginfo files. */
1238 if (__glibc_unlikely ((l->l_ld == 0 && type == ET_DYN) || empty_dynamic))
1239 {
1240 errstring = N_("object file has no dynamic section");
1241 goto lose;
1242 }
1243
1244 /* Length of the sections to be loaded. */
1245 maplength = loadcmds[nloadcmds - 1].allocend - loadcmds[0].mapstart;
1246
1247 /* Now process the load commands and map segments into memory.
1248 This is responsible for filling in:
1249 l_map_start, l_map_end, l_addr, l_contiguous, l_text_end, l_phdr
1250 */
1251 errstring = _dl_map_segments (l, fd, header, type, loadcmds, nloadcmds,
1252 maplength, has_holes, loader);
1253 if (__glibc_unlikely (errstring != NULL))
1254 {
1255 /* Mappings can be in an inconsistent state: avoid unmap. */
1256 l->l_map_start = l->l_map_end = 0;
1257 goto lose;
1258 }
1259 }
1260
1261 if (l->l_ld != 0)
1262 l->l_ld = (ElfW(Dyn) *) ((ElfW(Addr)) l->l_ld + l->l_addr);
1263
1264 elf_get_dynamic_info (l, false, false);
1265
1266 /* Make sure we are not dlopen'ing an object that has the
1267 DF_1_NOOPEN flag set, or a PIE object. */
1268 if ((__glibc_unlikely (l->l_flags_1 & DF_1_NOOPEN)
1269 && (mode & __RTLD_DLOPEN))
1270 || (__glibc_unlikely (l->l_flags_1 & DF_1_PIE)
1271 && __glibc_unlikely ((mode & __RTLD_OPENEXEC) == 0)))
1272 {
1273 if (l->l_flags_1 & DF_1_PIE)
1274 errstring
1275 = N_("cannot dynamically load position-independent executable");
1276 else
1277 errstring = N_("shared object cannot be dlopen()ed");
1278 goto lose;
1279 }
1280
1281 if (l->l_phdr == NULL)
1282 {
1283 /* The program header is not contained in any of the segments.
1284 We have to allocate memory ourself and copy it over from out
1285 temporary place. */
1286 ElfW(Phdr) *newp = (ElfW(Phdr) *) malloc (header->e_phnum
1287 * sizeof (ElfW(Phdr)));
1288 if (newp == NULL)
1289 {
1290 errstring = N_("cannot allocate memory for program header");
1291 goto lose_errno;
1292 }
1293
1294 l->l_phdr = memcpy (newp, phdr,
1295 (header->e_phnum * sizeof (ElfW(Phdr))));
1296 l->l_phdr_allocated = 1;
1297 }
1298 else
1299 /* Adjust the PT_PHDR value by the runtime load address. */
1300 l->l_phdr = (ElfW(Phdr) *) ((ElfW(Addr)) l->l_phdr + l->l_addr);
1301
1302 if (__glibc_unlikely ((stack_flags &~ GL(dl_stack_flags)) & PF_X))
1303 {
1304 /* The stack is presently not executable, but this module
1305 requires that it be executable. We must change the
1306 protection of the variable which contains the flags used in
1307 the mprotect calls. */
1308 #ifdef SHARED
1309 if ((mode & (__RTLD_DLOPEN | __RTLD_AUDIT)) == __RTLD_DLOPEN)
1310 {
1311 const uintptr_t p = (uintptr_t) &__stack_prot & -GLRO(dl_pagesize);
1312 const size_t s = (uintptr_t) (&__stack_prot + 1) - p;
1313
1314 struct link_map *const m = &GL(dl_rtld_map);
1315 const uintptr_t relro_end = ((m->l_addr + m->l_relro_addr
1316 + m->l_relro_size)
1317 & -GLRO(dl_pagesize));
1318 if (__glibc_likely (p + s <= relro_end))
1319 {
1320 /* The variable lies in the region protected by RELRO. */
1321 if (__mprotect ((void *) p, s, PROT_READ|PROT_WRITE) < 0)
1322 {
1323 errstring = N_("cannot change memory protections");
1324 goto lose_errno;
1325 }
1326 __stack_prot |= PROT_READ|PROT_WRITE|PROT_EXEC;
1327 __mprotect ((void *) p, s, PROT_READ);
1328 }
1329 else
1330 __stack_prot |= PROT_READ|PROT_WRITE|PROT_EXEC;
1331 }
1332 else
1333 #endif
1334 __stack_prot |= PROT_READ|PROT_WRITE|PROT_EXEC;
1335
1336 #ifdef check_consistency
1337 check_consistency ();
1338 #endif
1339
1340 #if PTHREAD_IN_LIBC
1341 errval = _dl_make_stacks_executable (stack_endp);
1342 #else
1343 errval = (*GL(dl_make_stack_executable_hook)) (stack_endp);
1344 #endif
1345 if (errval)
1346 {
1347 errstring = N_("\
1348 cannot enable executable stack as shared object requires");
1349 goto lose;
1350 }
1351 }
1352
1353 /* Adjust the address of the TLS initialization image. */
1354 if (l->l_tls_initimage != NULL)
1355 l->l_tls_initimage = (char *) l->l_tls_initimage + l->l_addr;
1356
1357 /* Process program headers again after load segments are mapped in
1358 case processing requires accessing those segments. Scan program
1359 headers backward so that PT_NOTE can be skipped if PT_GNU_PROPERTY
1360 exits. */
1361 for (ph = &l->l_phdr[l->l_phnum]; ph != l->l_phdr; --ph)
1362 switch (ph[-1].p_type)
1363 {
1364 case PT_NOTE:
1365 _dl_process_pt_note (l, fd, &ph[-1]);
1366 break;
1367 case PT_GNU_PROPERTY:
1368 _dl_process_pt_gnu_property (l, fd, &ph[-1]);
1369 break;
1370 }
1371
1372 /* We are done mapping in the file. We no longer need the descriptor. */
1373 if (__glibc_unlikely (__close_nocancel (fd) != 0))
1374 {
1375 errstring = N_("cannot close file descriptor");
1376 goto lose_errno;
1377 }
1378 /* Signal that we closed the file. */
1379 fd = -1;
1380
1381 /* Failures before this point are handled locally via lose.
1382 There are no more failures in this function until return,
1383 to change that the cleanup handling needs to be updated. */
1384
1385 /* If this is ET_EXEC, we should have loaded it as lt_executable. */
1386 assert (type != ET_EXEC || l->l_type == lt_executable);
1387
1388 l->l_entry += l->l_addr;
1389
1390 if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_FILES))
1391 _dl_debug_printf ("\
1392 dynamic: 0x%0*lx base: 0x%0*lx size: 0x%0*Zx\n\
1393 entry: 0x%0*lx phdr: 0x%0*lx phnum: %*u\n\n",
1394 (int) sizeof (void *) * 2,
1395 (unsigned long int) l->l_ld,
1396 (int) sizeof (void *) * 2,
1397 (unsigned long int) l->l_addr,
1398 (int) sizeof (void *) * 2, maplength,
1399 (int) sizeof (void *) * 2,
1400 (unsigned long int) l->l_entry,
1401 (int) sizeof (void *) * 2,
1402 (unsigned long int) l->l_phdr,
1403 (int) sizeof (void *) * 2, l->l_phnum);
1404
1405 /* Set up the symbol hash table. */
1406 _dl_setup_hash (l);
1407
1408 /* If this object has DT_SYMBOLIC set modify now its scope. We don't
1409 have to do this for the main map. */
1410 if ((mode & RTLD_DEEPBIND) == 0
1411 && __glibc_unlikely (l->l_info[DT_SYMBOLIC] != NULL)
1412 && &l->l_searchlist != l->l_scope[0])
1413 {
1414 /* Create an appropriate searchlist. It contains only this map.
1415 This is the definition of DT_SYMBOLIC in SysVr4. */
1416 l->l_symbolic_searchlist.r_list[0] = l;
1417 l->l_symbolic_searchlist.r_nlist = 1;
1418
1419 /* Now move the existing entries one back. */
1420 memmove (&l->l_scope[1], &l->l_scope[0],
1421 (l->l_scope_max - 1) * sizeof (l->l_scope[0]));
1422
1423 /* Now add the new entry. */
1424 l->l_scope[0] = &l->l_symbolic_searchlist;
1425 }
1426
1427 /* Remember whether this object must be initialized first. */
1428 if (l->l_flags_1 & DF_1_INITFIRST)
1429 GL(dl_initfirst) = l;
1430
1431 /* Finally the file information. */
1432 l->l_file_id = id;
1433
1434 #ifdef SHARED
1435 /* When auditing is used the recorded names might not include the
1436 name by which the DSO is actually known. Add that as well. */
1437 if (__glibc_unlikely (origname != NULL))
1438 add_name_to_object (l, origname);
1439 #else
1440 /* Audit modules only exist when linking is dynamic so ORIGNAME
1441 cannot be non-NULL. */
1442 assert (origname == NULL);
1443 #endif
1444
1445 /* When we profile the SONAME might be needed for something else but
1446 loading. Add it right away. */
1447 if (__glibc_unlikely (GLRO(dl_profile) != NULL)
1448 && l->l_info[DT_SONAME] != NULL)
1449 add_name_to_object (l, ((const char *) D_PTR (l, l_info[DT_STRTAB])
1450 + l->l_info[DT_SONAME]->d_un.d_val));
1451
1452 /* If we have newly loaded libc.so, update the namespace
1453 description. */
1454 if (GL(dl_ns)[nsid].libc_map == NULL
1455 && l->l_info[DT_SONAME] != NULL
1456 && strcmp (((const char *) D_PTR (l, l_info[DT_STRTAB])
1457 + l->l_info[DT_SONAME]->d_un.d_val), LIBC_SO) == 0)
1458 GL(dl_ns)[nsid].libc_map = l;
1459
1460 /* _dl_close can only eventually undo the module ID assignment (via
1461 remove_slotinfo) if this function returns a pointer to a link
1462 map. Therefore, delay this step until all possibilities for
1463 failure have been excluded. */
1464 if (l->l_tls_blocksize > 0
1465 && (__glibc_likely (l->l_type == lt_library)
1466 /* If GL(dl_tls_dtv_slotinfo_list) == NULL, then rtld.c did
1467 not set up TLS data structures, so don't use them now. */
1468 || __glibc_likely (GL(dl_tls_dtv_slotinfo_list) != NULL)))
1469 /* Assign the next available module ID. */
1470 _dl_assign_tls_modid (l);
1471
1472 #ifdef DL_AFTER_LOAD
1473 DL_AFTER_LOAD (l);
1474 #endif
1475
1476 /* Now that the object is fully initialized add it to the object list. */
1477 _dl_add_to_namespace_list (l, nsid);
1478
1479 /* Signal that we are going to add new objects. */
1480 if (r->r_state == RT_CONSISTENT)
1481 {
1482 #ifdef SHARED
1483 /* Auditing checkpoint: we are going to add new objects. Since this
1484 is called after _dl_add_to_namespace_list the namespace is guaranteed
1485 to not be empty. */
1486 if ((mode & __RTLD_AUDIT) == 0)
1487 _dl_audit_activity_nsid (nsid, LA_ACT_ADD);
1488 #endif
1489
1490 /* Notify the debugger we have added some objects. We need to
1491 call _dl_debug_initialize in a static program in case dynamic
1492 linking has not been used before. */
1493 r->r_state = RT_ADD;
1494 _dl_debug_state ();
1495 LIBC_PROBE (map_start, 2, nsid, r);
1496 make_consistent = true;
1497 }
1498 else
1499 assert (r->r_state == RT_ADD);
1500
1501 #ifdef SHARED
1502 /* Auditing checkpoint: we have a new object. */
1503 if (!GL(dl_ns)[l->l_ns]._ns_loaded->l_auditing)
1504 _dl_audit_objopen (l, nsid);
1505 #endif
1506
1507 return l;
1508 }
1509
1510 /* Print search path. */
1511 static void
print_search_path(struct r_search_path_elem ** list,const char * what,const char * name)1512 print_search_path (struct r_search_path_elem **list,
1513 const char *what, const char *name)
1514 {
1515 char buf[max_dirnamelen + max_capstrlen];
1516 int first = 1;
1517
1518 _dl_debug_printf (" search path=");
1519
1520 while (*list != NULL && (*list)->what == what) /* Yes, ==. */
1521 {
1522 char *endp = __mempcpy (buf, (*list)->dirname, (*list)->dirnamelen);
1523 size_t cnt;
1524
1525 for (cnt = 0; cnt < ncapstr; ++cnt)
1526 if ((*list)->status[cnt] != nonexisting)
1527 {
1528 #ifdef SHARED
1529 char *cp = __mempcpy (endp, capstr[cnt].str, capstr[cnt].len);
1530 if (cp == buf || (cp == buf + 1 && buf[0] == '/'))
1531 cp[0] = '\0';
1532 else
1533 cp[-1] = '\0';
1534 #else
1535 *endp = '\0';
1536 #endif
1537
1538 _dl_debug_printf_c (first ? "%s" : ":%s", buf);
1539 first = 0;
1540 }
1541
1542 ++list;
1543 }
1544
1545 if (name != NULL)
1546 _dl_debug_printf_c ("\t\t(%s from file %s)\n", what,
1547 DSO_FILENAME (name));
1548 else
1549 _dl_debug_printf_c ("\t\t(%s)\n", what);
1550 }
1551
1552 /* Open a file and verify it is an ELF file for this architecture. We
1553 ignore only ELF files for other architectures. Non-ELF files and
1554 ELF files with different header information cause fatal errors since
1555 this could mean there is something wrong in the installation and the
1556 user might want to know about this.
1557
1558 If FD is not -1, then the file is already open and FD refers to it.
1559 In that case, FD is consumed for both successful and error returns. */
1560 static int
open_verify(const char * name,int fd,struct filebuf * fbp,struct link_map * loader,int whatcode,int mode,bool * found_other_class,bool free_name)1561 open_verify (const char *name, int fd,
1562 struct filebuf *fbp, struct link_map *loader,
1563 int whatcode, int mode, bool *found_other_class, bool free_name)
1564 {
1565 /* This is the expected ELF header. */
1566 #define ELF32_CLASS ELFCLASS32
1567 #define ELF64_CLASS ELFCLASS64
1568 #ifndef VALID_ELF_HEADER
1569 # define VALID_ELF_HEADER(hdr,exp,size) (memcmp (hdr, exp, size) == 0)
1570 # define VALID_ELF_OSABI(osabi) (osabi == ELFOSABI_SYSV)
1571 # define VALID_ELF_ABIVERSION(osabi,ver) (ver == 0)
1572 #elif defined MORE_ELF_HEADER_DATA
1573 MORE_ELF_HEADER_DATA;
1574 #endif
1575 static const unsigned char expected[EI_NIDENT] =
1576 {
1577 [EI_MAG0] = ELFMAG0,
1578 [EI_MAG1] = ELFMAG1,
1579 [EI_MAG2] = ELFMAG2,
1580 [EI_MAG3] = ELFMAG3,
1581 [EI_CLASS] = ELFW(CLASS),
1582 [EI_DATA] = byteorder,
1583 [EI_VERSION] = EV_CURRENT,
1584 [EI_OSABI] = ELFOSABI_SYSV,
1585 [EI_ABIVERSION] = 0
1586 };
1587 static const struct
1588 {
1589 ElfW(Word) vendorlen;
1590 ElfW(Word) datalen;
1591 ElfW(Word) type;
1592 char vendor[4];
1593 } expected_note = { 4, 16, 1, "GNU" };
1594 /* Initialize it to make the compiler happy. */
1595 const char *errstring = NULL;
1596 int errval = 0;
1597
1598 #ifdef SHARED
1599 /* Give the auditing libraries a chance. */
1600 if (__glibc_unlikely (GLRO(dl_naudit) > 0))
1601 {
1602 const char *original_name = name;
1603 name = _dl_audit_objsearch (name, loader, whatcode);
1604 if (name == NULL)
1605 return -1;
1606
1607 if (fd != -1 && name != original_name && strcmp (name, original_name))
1608 {
1609 /* An audit library changed what we're supposed to open,
1610 so FD no longer matches it. */
1611 __close_nocancel (fd);
1612 fd = -1;
1613 }
1614 }
1615 #endif
1616
1617 if (fd == -1)
1618 /* Open the file. We always open files read-only. */
1619 fd = __open64_nocancel (name, O_RDONLY | O_CLOEXEC);
1620
1621 if (fd != -1)
1622 {
1623 ElfW(Ehdr) *ehdr;
1624 ElfW(Phdr) *phdr, *ph;
1625 ElfW(Word) *abi_note;
1626 ElfW(Word) *abi_note_malloced = NULL;
1627 unsigned int osversion;
1628 size_t maplength;
1629
1630 /* We successfully opened the file. Now verify it is a file
1631 we can use. */
1632 __set_errno (0);
1633 fbp->len = 0;
1634 assert (sizeof (fbp->buf) > sizeof (ElfW(Ehdr)));
1635 /* Read in the header. */
1636 do
1637 {
1638 ssize_t retlen = __read_nocancel (fd, fbp->buf + fbp->len,
1639 sizeof (fbp->buf) - fbp->len);
1640 if (retlen <= 0)
1641 break;
1642 fbp->len += retlen;
1643 }
1644 while (__glibc_unlikely (fbp->len < sizeof (ElfW(Ehdr))));
1645
1646 /* This is where the ELF header is loaded. */
1647 ehdr = (ElfW(Ehdr) *) fbp->buf;
1648
1649 /* Now run the tests. */
1650 if (__glibc_unlikely (fbp->len < (ssize_t) sizeof (ElfW(Ehdr))))
1651 {
1652 errval = errno;
1653 errstring = (errval == 0
1654 ? N_("file too short") : N_("cannot read file data"));
1655 lose:
1656 if (free_name)
1657 {
1658 char *realname = (char *) name;
1659 name = strdupa (realname);
1660 free (realname);
1661 }
1662 __close_nocancel (fd);
1663 _dl_signal_error (errval, name, NULL, errstring);
1664 }
1665
1666 /* See whether the ELF header is what we expect. */
1667 if (__glibc_unlikely (! VALID_ELF_HEADER (ehdr->e_ident, expected,
1668 EI_ABIVERSION)
1669 || !VALID_ELF_ABIVERSION (ehdr->e_ident[EI_OSABI],
1670 ehdr->e_ident[EI_ABIVERSION])
1671 || memcmp (&ehdr->e_ident[EI_PAD],
1672 &expected[EI_PAD],
1673 EI_NIDENT - EI_PAD) != 0))
1674 {
1675 /* Something is wrong. */
1676 const Elf32_Word *magp = (const void *) ehdr->e_ident;
1677 if (*magp !=
1678 #if BYTE_ORDER == LITTLE_ENDIAN
1679 ((ELFMAG0 << (EI_MAG0 * 8))
1680 | (ELFMAG1 << (EI_MAG1 * 8))
1681 | (ELFMAG2 << (EI_MAG2 * 8))
1682 | (ELFMAG3 << (EI_MAG3 * 8)))
1683 #else
1684 ((ELFMAG0 << (EI_MAG3 * 8))
1685 | (ELFMAG1 << (EI_MAG2 * 8))
1686 | (ELFMAG2 << (EI_MAG1 * 8))
1687 | (ELFMAG3 << (EI_MAG0 * 8)))
1688 #endif
1689 )
1690 errstring = N_("invalid ELF header");
1691 else if (ehdr->e_ident[EI_CLASS] != ELFW(CLASS))
1692 {
1693 /* This is not a fatal error. On architectures where
1694 32-bit and 64-bit binaries can be run this might
1695 happen. */
1696 *found_other_class = true;
1697 goto close_and_out;
1698 }
1699 else if (ehdr->e_ident[EI_DATA] != byteorder)
1700 {
1701 if (BYTE_ORDER == BIG_ENDIAN)
1702 errstring = N_("ELF file data encoding not big-endian");
1703 else
1704 errstring = N_("ELF file data encoding not little-endian");
1705 }
1706 else if (ehdr->e_ident[EI_VERSION] != EV_CURRENT)
1707 errstring
1708 = N_("ELF file version ident does not match current one");
1709 /* XXX We should be able so set system specific versions which are
1710 allowed here. */
1711 else if (!VALID_ELF_OSABI (ehdr->e_ident[EI_OSABI]))
1712 errstring = N_("ELF file OS ABI invalid");
1713 else if (!VALID_ELF_ABIVERSION (ehdr->e_ident[EI_OSABI],
1714 ehdr->e_ident[EI_ABIVERSION]))
1715 errstring = N_("ELF file ABI version invalid");
1716 else if (memcmp (&ehdr->e_ident[EI_PAD], &expected[EI_PAD],
1717 EI_NIDENT - EI_PAD) != 0)
1718 errstring = N_("nonzero padding in e_ident");
1719 else
1720 /* Otherwise we don't know what went wrong. */
1721 errstring = N_("internal error");
1722
1723 goto lose;
1724 }
1725
1726 if (__glibc_unlikely (ehdr->e_version != EV_CURRENT))
1727 {
1728 errstring = N_("ELF file version does not match current one");
1729 goto lose;
1730 }
1731 if (! __glibc_likely (elf_machine_matches_host (ehdr)))
1732 goto close_and_out;
1733 else if (__glibc_unlikely (ehdr->e_type != ET_DYN
1734 && ehdr->e_type != ET_EXEC))
1735 {
1736 errstring = N_("only ET_DYN and ET_EXEC can be loaded");
1737 goto lose;
1738 }
1739 else if (__glibc_unlikely (ehdr->e_phentsize != sizeof (ElfW(Phdr))))
1740 {
1741 errstring = N_("ELF file's phentsize not the expected size");
1742 goto lose;
1743 }
1744
1745 maplength = ehdr->e_phnum * sizeof (ElfW(Phdr));
1746 if (ehdr->e_phoff + maplength <= (size_t) fbp->len)
1747 phdr = (void *) (fbp->buf + ehdr->e_phoff);
1748 else
1749 {
1750 phdr = alloca (maplength);
1751 if ((size_t) __pread64_nocancel (fd, (void *) phdr, maplength,
1752 ehdr->e_phoff) != maplength)
1753 {
1754 read_error:
1755 errval = errno;
1756 errstring = N_("cannot read file data");
1757 goto lose;
1758 }
1759 }
1760
1761 if (__glibc_unlikely (elf_machine_reject_phdr_p
1762 (phdr, ehdr->e_phnum, fbp->buf, fbp->len,
1763 loader, fd)))
1764 goto close_and_out;
1765
1766 /* Check .note.ABI-tag if present. */
1767 for (ph = phdr; ph < &phdr[ehdr->e_phnum]; ++ph)
1768 if (ph->p_type == PT_NOTE && ph->p_filesz >= 32
1769 && (ph->p_align == 4 || ph->p_align == 8))
1770 {
1771 ElfW(Addr) size = ph->p_filesz;
1772
1773 if (ph->p_offset + size <= (size_t) fbp->len)
1774 abi_note = (void *) (fbp->buf + ph->p_offset);
1775 else
1776 {
1777 /* Note: __libc_use_alloca is not usable here, because
1778 thread info may not have been set up yet. */
1779 if (size < __MAX_ALLOCA_CUTOFF)
1780 abi_note = alloca (size);
1781 else
1782 {
1783 /* There could be multiple PT_NOTEs. */
1784 abi_note_malloced = realloc (abi_note_malloced, size);
1785 if (abi_note_malloced == NULL)
1786 goto read_error;
1787
1788 abi_note = abi_note_malloced;
1789 }
1790 if (__pread64_nocancel (fd, (void *) abi_note, size,
1791 ph->p_offset) != size)
1792 {
1793 free (abi_note_malloced);
1794 goto read_error;
1795 }
1796 }
1797
1798 while (memcmp (abi_note, &expected_note, sizeof (expected_note)))
1799 {
1800 ElfW(Addr) note_size
1801 = ELF_NOTE_NEXT_OFFSET (abi_note[0], abi_note[1],
1802 ph->p_align);
1803
1804 if (size - 32 < note_size)
1805 {
1806 size = 0;
1807 break;
1808 }
1809 size -= note_size;
1810 abi_note = (void *) abi_note + note_size;
1811 }
1812
1813 if (size == 0)
1814 continue;
1815
1816 osversion = (abi_note[5] & 0xff) * 65536
1817 + (abi_note[6] & 0xff) * 256
1818 + (abi_note[7] & 0xff);
1819 if (abi_note[4] != __ABI_TAG_OS
1820 || (GLRO(dl_osversion) && GLRO(dl_osversion) < osversion))
1821 {
1822 close_and_out:
1823 __close_nocancel (fd);
1824 __set_errno (ENOENT);
1825 fd = -1;
1826 }
1827
1828 break;
1829 }
1830 free (abi_note_malloced);
1831 }
1832
1833 return fd;
1834 }
1835
1836 /* Try to open NAME in one of the directories in *DIRSP.
1837 Return the fd, or -1. If successful, fill in *REALNAME
1838 with the malloc'd full directory name. If it turns out
1839 that none of the directories in *DIRSP exists, *DIRSP is
1840 replaced with (void *) -1, and the old value is free()d
1841 if MAY_FREE_DIRS is true. */
1842
1843 static int
open_path(const char * name,size_t namelen,int mode,struct r_search_path_struct * sps,char ** realname,struct filebuf * fbp,struct link_map * loader,int whatcode,bool * found_other_class)1844 open_path (const char *name, size_t namelen, int mode,
1845 struct r_search_path_struct *sps, char **realname,
1846 struct filebuf *fbp, struct link_map *loader, int whatcode,
1847 bool *found_other_class)
1848 {
1849 struct r_search_path_elem **dirs = sps->dirs;
1850 char *buf;
1851 int fd = -1;
1852 const char *current_what = NULL;
1853 int any = 0;
1854
1855 if (__glibc_unlikely (dirs == NULL))
1856 /* We're called before _dl_init_paths when loading the main executable
1857 given on the command line when rtld is run directly. */
1858 return -1;
1859
1860 buf = alloca (max_dirnamelen + max_capstrlen + namelen);
1861 do
1862 {
1863 struct r_search_path_elem *this_dir = *dirs;
1864 size_t buflen = 0;
1865 size_t cnt;
1866 char *edp;
1867 int here_any = 0;
1868 int err;
1869
1870 /* If we are debugging the search for libraries print the path
1871 now if it hasn't happened now. */
1872 if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_LIBS)
1873 && current_what != this_dir->what)
1874 {
1875 current_what = this_dir->what;
1876 print_search_path (dirs, current_what, this_dir->where);
1877 }
1878
1879 edp = (char *) __mempcpy (buf, this_dir->dirname, this_dir->dirnamelen);
1880 for (cnt = 0; fd == -1 && cnt < ncapstr; ++cnt)
1881 {
1882 /* Skip this directory if we know it does not exist. */
1883 if (this_dir->status[cnt] == nonexisting)
1884 continue;
1885
1886 #ifdef SHARED
1887 buflen =
1888 ((char *) __mempcpy (__mempcpy (edp, capstr[cnt].str,
1889 capstr[cnt].len),
1890 name, namelen)
1891 - buf);
1892 #else
1893 buflen = (char *) __mempcpy (edp, name, namelen) - buf;
1894 #endif
1895
1896 /* Print name we try if this is wanted. */
1897 if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_LIBS))
1898 _dl_debug_printf (" trying file=%s\n", buf);
1899
1900 fd = open_verify (buf, -1, fbp, loader, whatcode, mode,
1901 found_other_class, false);
1902 if (this_dir->status[cnt] == unknown)
1903 {
1904 if (fd != -1)
1905 this_dir->status[cnt] = existing;
1906 /* Do not update the directory information when loading
1907 auditing code. We must try to disturb the program as
1908 little as possible. */
1909 else if (loader == NULL
1910 || GL(dl_ns)[loader->l_ns]._ns_loaded->l_auditing == 0)
1911 {
1912 /* We failed to open machine dependent library. Let's
1913 test whether there is any directory at all. */
1914 struct __stat64_t64 st;
1915
1916 buf[buflen - namelen - 1] = '\0';
1917
1918 if (__stat64_time64 (buf, &st) != 0
1919 || ! S_ISDIR (st.st_mode))
1920 /* The directory does not exist or it is no directory. */
1921 this_dir->status[cnt] = nonexisting;
1922 else
1923 this_dir->status[cnt] = existing;
1924 }
1925 }
1926
1927 /* Remember whether we found any existing directory. */
1928 here_any |= this_dir->status[cnt] != nonexisting;
1929
1930 if (fd != -1 && __glibc_unlikely (mode & __RTLD_SECURE)
1931 && __libc_enable_secure)
1932 {
1933 /* This is an extra security effort to make sure nobody can
1934 preload broken shared objects which are in the trusted
1935 directories and so exploit the bugs. */
1936 struct __stat64_t64 st;
1937
1938 if (__fstat64_time64 (fd, &st) != 0
1939 || (st.st_mode & S_ISUID) == 0)
1940 {
1941 /* The shared object cannot be tested for being SUID
1942 or this bit is not set. In this case we must not
1943 use this object. */
1944 __close_nocancel (fd);
1945 fd = -1;
1946 /* We simply ignore the file, signal this by setting
1947 the error value which would have been set by `open'. */
1948 errno = ENOENT;
1949 }
1950 }
1951 }
1952
1953 if (fd != -1)
1954 {
1955 *realname = (char *) malloc (buflen);
1956 if (*realname != NULL)
1957 {
1958 memcpy (*realname, buf, buflen);
1959 return fd;
1960 }
1961 else
1962 {
1963 /* No memory for the name, we certainly won't be able
1964 to load and link it. */
1965 __close_nocancel (fd);
1966 return -1;
1967 }
1968 }
1969 if (here_any && (err = errno) != ENOENT && err != EACCES)
1970 /* The file exists and is readable, but something went wrong. */
1971 return -1;
1972
1973 /* Remember whether we found anything. */
1974 any |= here_any;
1975 }
1976 while (*++dirs != NULL);
1977
1978 /* Remove the whole path if none of the directories exists. */
1979 if (__glibc_unlikely (! any))
1980 {
1981 /* Paths which were allocated using the minimal malloc() in ld.so
1982 must not be freed using the general free() in libc. */
1983 if (sps->malloced)
1984 free (sps->dirs);
1985
1986 /* __rtld_search_dirs and __rtld_env_path_list are
1987 attribute_relro, therefore avoid writing to them. */
1988 if (sps != &__rtld_search_dirs && sps != &__rtld_env_path_list)
1989 sps->dirs = (void *) -1;
1990 }
1991
1992 return -1;
1993 }
1994
1995 /* Map in the shared object file NAME. */
1996
1997 struct link_map *
_dl_map_object(struct link_map * loader,const char * name,int type,int trace_mode,int mode,Lmid_t nsid)1998 _dl_map_object (struct link_map *loader, const char *name,
1999 int type, int trace_mode, int mode, Lmid_t nsid)
2000 {
2001 int fd;
2002 const char *origname = NULL;
2003 char *realname;
2004 char *name_copy;
2005 struct link_map *l;
2006 struct filebuf fb;
2007
2008 assert (nsid >= 0);
2009 assert (nsid < GL(dl_nns));
2010
2011 /* Look for this name among those already loaded. */
2012 for (l = GL(dl_ns)[nsid]._ns_loaded; l; l = l->l_next)
2013 {
2014 /* If the requested name matches the soname of a loaded object,
2015 use that object. Elide this check for names that have not
2016 yet been opened. */
2017 if (__glibc_unlikely ((l->l_faked | l->l_removed) != 0))
2018 continue;
2019 if (!_dl_name_match_p (name, l))
2020 {
2021 const char *soname;
2022
2023 if (__glibc_likely (l->l_soname_added)
2024 || l->l_info[DT_SONAME] == NULL)
2025 continue;
2026
2027 soname = ((const char *) D_PTR (l, l_info[DT_STRTAB])
2028 + l->l_info[DT_SONAME]->d_un.d_val);
2029 if (strcmp (name, soname) != 0)
2030 continue;
2031
2032 /* We have a match on a new name -- cache it. */
2033 add_name_to_object (l, soname);
2034 l->l_soname_added = 1;
2035 }
2036
2037 /* We have a match. */
2038 return l;
2039 }
2040
2041 /* Display information if we are debugging. */
2042 if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_FILES)
2043 && loader != NULL)
2044 _dl_debug_printf ((mode & __RTLD_CALLMAP) == 0
2045 ? "\nfile=%s [%lu]; needed by %s [%lu]\n"
2046 : "\nfile=%s [%lu]; dynamically loaded by %s [%lu]\n",
2047 name, nsid, DSO_FILENAME (loader->l_name), loader->l_ns);
2048
2049 #ifdef SHARED
2050 /* Give the auditing libraries a chance to change the name before we
2051 try anything. */
2052 if (__glibc_unlikely (GLRO(dl_naudit) > 0))
2053 {
2054 const char *before = name;
2055 name = _dl_audit_objsearch (name, loader, LA_SER_ORIG);
2056 if (name == NULL)
2057 {
2058 fd = -1;
2059 goto no_file;
2060 }
2061 if (before != name && strcmp (before, name) != 0)
2062 origname = before;
2063 }
2064 #endif
2065
2066 /* Will be true if we found a DSO which is of the other ELF class. */
2067 bool found_other_class = false;
2068
2069 if (strchr (name, '/') == NULL)
2070 {
2071 /* Search for NAME in several places. */
2072
2073 size_t namelen = strlen (name) + 1;
2074
2075 if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_LIBS))
2076 _dl_debug_printf ("find library=%s [%lu]; searching\n", name, nsid);
2077
2078 fd = -1;
2079
2080 /* When the object has the RUNPATH information we don't use any
2081 RPATHs. */
2082 if (loader == NULL || loader->l_info[DT_RUNPATH] == NULL)
2083 {
2084 /* This is the executable's map (if there is one). Make sure that
2085 we do not look at it twice. */
2086 struct link_map *main_map = GL(dl_ns)[LM_ID_BASE]._ns_loaded;
2087 bool did_main_map = false;
2088
2089 /* First try the DT_RPATH of the dependent object that caused NAME
2090 to be loaded. Then that object's dependent, and on up. */
2091 for (l = loader; l; l = l->l_loader)
2092 if (cache_rpath (l, &l->l_rpath_dirs, DT_RPATH, "RPATH"))
2093 {
2094 fd = open_path (name, namelen, mode,
2095 &l->l_rpath_dirs,
2096 &realname, &fb, loader, LA_SER_RUNPATH,
2097 &found_other_class);
2098 if (fd != -1)
2099 break;
2100
2101 did_main_map |= l == main_map;
2102 }
2103
2104 /* If dynamically linked, try the DT_RPATH of the executable
2105 itself. NB: we do this for lookups in any namespace. */
2106 if (fd == -1 && !did_main_map
2107 && main_map != NULL && main_map->l_type != lt_loaded
2108 && cache_rpath (main_map, &main_map->l_rpath_dirs, DT_RPATH,
2109 "RPATH"))
2110 fd = open_path (name, namelen, mode,
2111 &main_map->l_rpath_dirs,
2112 &realname, &fb, loader ?: main_map, LA_SER_RUNPATH,
2113 &found_other_class);
2114 }
2115
2116 /* Try the LD_LIBRARY_PATH environment variable. */
2117 if (fd == -1 && __rtld_env_path_list.dirs != (void *) -1)
2118 fd = open_path (name, namelen, mode, &__rtld_env_path_list,
2119 &realname, &fb,
2120 loader ?: GL(dl_ns)[LM_ID_BASE]._ns_loaded,
2121 LA_SER_LIBPATH, &found_other_class);
2122
2123 /* Look at the RUNPATH information for this binary. */
2124 if (fd == -1 && loader != NULL
2125 && cache_rpath (loader, &loader->l_runpath_dirs,
2126 DT_RUNPATH, "RUNPATH"))
2127 fd = open_path (name, namelen, mode,
2128 &loader->l_runpath_dirs, &realname, &fb, loader,
2129 LA_SER_RUNPATH, &found_other_class);
2130
2131 if (fd == -1)
2132 {
2133 realname = _dl_sysdep_open_object (name, namelen, &fd);
2134 if (realname != NULL)
2135 {
2136 fd = open_verify (realname, fd,
2137 &fb, loader ?: GL(dl_ns)[nsid]._ns_loaded,
2138 LA_SER_CONFIG, mode, &found_other_class,
2139 false);
2140 if (fd == -1)
2141 free (realname);
2142 }
2143 }
2144
2145 #ifdef USE_LDCONFIG
2146 if (fd == -1
2147 && (__glibc_likely ((mode & __RTLD_SECURE) == 0)
2148 || ! __libc_enable_secure)
2149 && __glibc_likely (GLRO(dl_inhibit_cache) == 0))
2150 {
2151 /* Check the list of libraries in the file /etc/ld.so.cache,
2152 for compatibility with Linux's ldconfig program. */
2153 char *cached = _dl_load_cache_lookup (name);
2154
2155 if (cached != NULL)
2156 {
2157 // XXX Correct to unconditionally default to namespace 0?
2158 l = (loader
2159 ?: GL(dl_ns)[LM_ID_BASE]._ns_loaded
2160 # ifdef SHARED
2161 ?: &GL(dl_rtld_map)
2162 # endif
2163 );
2164
2165 /* If the loader has the DF_1_NODEFLIB flag set we must not
2166 use a cache entry from any of these directories. */
2167 if (__glibc_unlikely (l->l_flags_1 & DF_1_NODEFLIB))
2168 {
2169 const char *dirp = system_dirs;
2170 unsigned int cnt = 0;
2171
2172 do
2173 {
2174 if (memcmp (cached, dirp, system_dirs_len[cnt]) == 0)
2175 {
2176 /* The prefix matches. Don't use the entry. */
2177 free (cached);
2178 cached = NULL;
2179 break;
2180 }
2181
2182 dirp += system_dirs_len[cnt] + 1;
2183 ++cnt;
2184 }
2185 while (cnt < nsystem_dirs_len);
2186 }
2187
2188 if (cached != NULL)
2189 {
2190 fd = open_verify (cached, -1,
2191 &fb, loader ?: GL(dl_ns)[nsid]._ns_loaded,
2192 LA_SER_CONFIG, mode, &found_other_class,
2193 false);
2194 if (__glibc_likely (fd != -1))
2195 realname = cached;
2196 else
2197 free (cached);
2198 }
2199 }
2200 }
2201 #endif
2202
2203 /* Finally, try the default path. */
2204 if (fd == -1
2205 && ((l = loader ?: GL(dl_ns)[nsid]._ns_loaded) == NULL
2206 || __glibc_likely (!(l->l_flags_1 & DF_1_NODEFLIB)))
2207 && __rtld_search_dirs.dirs != (void *) -1)
2208 fd = open_path (name, namelen, mode, &__rtld_search_dirs,
2209 &realname, &fb, l, LA_SER_DEFAULT, &found_other_class);
2210
2211 /* Add another newline when we are tracing the library loading. */
2212 if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_LIBS))
2213 _dl_debug_printf ("\n");
2214 }
2215 else
2216 {
2217 /* The path may contain dynamic string tokens. */
2218 realname = (loader
2219 ? expand_dynamic_string_token (loader, name)
2220 : __strdup (name));
2221 if (realname == NULL)
2222 fd = -1;
2223 else
2224 {
2225 fd = open_verify (realname, -1, &fb,
2226 loader ?: GL(dl_ns)[nsid]._ns_loaded, 0, mode,
2227 &found_other_class, true);
2228 if (__glibc_unlikely (fd == -1))
2229 free (realname);
2230 }
2231 }
2232
2233 #ifdef SHARED
2234 no_file:
2235 #endif
2236 /* In case the LOADER information has only been provided to get to
2237 the appropriate RUNPATH/RPATH information we do not need it
2238 anymore. */
2239 if (mode & __RTLD_CALLMAP)
2240 loader = NULL;
2241
2242 if (__glibc_unlikely (fd == -1))
2243 {
2244 if (trace_mode
2245 && __glibc_likely ((GLRO(dl_debug_mask) & DL_DEBUG_PRELINK) == 0))
2246 {
2247 /* We haven't found an appropriate library. But since we
2248 are only interested in the list of libraries this isn't
2249 so severe. Fake an entry with all the information we
2250 have. */
2251 static const Elf_Symndx dummy_bucket = STN_UNDEF;
2252
2253 /* Allocate a new object map. */
2254 if ((name_copy = __strdup (name)) == NULL
2255 || (l = _dl_new_object (name_copy, name, type, loader,
2256 mode, nsid)) == NULL)
2257 {
2258 free (name_copy);
2259 _dl_signal_error (ENOMEM, name, NULL,
2260 N_("cannot create shared object descriptor"));
2261 }
2262 /* Signal that this is a faked entry. */
2263 l->l_faked = 1;
2264 /* Since the descriptor is initialized with zero we do not
2265 have do this here.
2266 l->l_reserved = 0; */
2267 l->l_buckets = &dummy_bucket;
2268 l->l_nbuckets = 1;
2269 l->l_relocated = 1;
2270
2271 /* Enter the object in the object list. */
2272 _dl_add_to_namespace_list (l, nsid);
2273
2274 return l;
2275 }
2276 else if (found_other_class)
2277 _dl_signal_error (0, name, NULL,
2278 ELFW(CLASS) == ELFCLASS32
2279 ? N_("wrong ELF class: ELFCLASS64")
2280 : N_("wrong ELF class: ELFCLASS32"));
2281 else
2282 _dl_signal_error (errno, name, NULL,
2283 N_("cannot open shared object file"));
2284 }
2285
2286 void *stack_end = __libc_stack_end;
2287 return _dl_map_object_from_fd (name, origname, fd, &fb, realname, loader,
2288 type, mode, &stack_end, nsid);
2289 }
2290
2291 struct add_path_state
2292 {
2293 bool counting;
2294 unsigned int idx;
2295 Dl_serinfo *si;
2296 char *allocptr;
2297 };
2298
2299 static void
add_path(struct add_path_state * p,const struct r_search_path_struct * sps,unsigned int flags)2300 add_path (struct add_path_state *p, const struct r_search_path_struct *sps,
2301 unsigned int flags)
2302 {
2303 if (sps->dirs != (void *) -1)
2304 {
2305 struct r_search_path_elem **dirs = sps->dirs;
2306 do
2307 {
2308 const struct r_search_path_elem *const r = *dirs++;
2309 if (p->counting)
2310 {
2311 p->si->dls_cnt++;
2312 p->si->dls_size += MAX (2, r->dirnamelen);
2313 }
2314 else
2315 {
2316 Dl_serpath *const sp = &p->si->dls_serpath[p->idx++];
2317 sp->dls_name = p->allocptr;
2318 if (r->dirnamelen < 2)
2319 *p->allocptr++ = r->dirnamelen ? '/' : '.';
2320 else
2321 p->allocptr = __mempcpy (p->allocptr,
2322 r->dirname, r->dirnamelen - 1);
2323 *p->allocptr++ = '\0';
2324 sp->dls_flags = flags;
2325 }
2326 }
2327 while (*dirs != NULL);
2328 }
2329 }
2330
2331 void
_dl_rtld_di_serinfo(struct link_map * loader,Dl_serinfo * si,bool counting)2332 _dl_rtld_di_serinfo (struct link_map *loader, Dl_serinfo *si, bool counting)
2333 {
2334 if (counting)
2335 {
2336 si->dls_cnt = 0;
2337 si->dls_size = 0;
2338 }
2339
2340 struct add_path_state p =
2341 {
2342 .counting = counting,
2343 .idx = 0,
2344 .si = si,
2345 .allocptr = (char *) &si->dls_serpath[si->dls_cnt]
2346 };
2347
2348 # define add_path(p, sps, flags) add_path(p, sps, 0) /* XXX */
2349
2350 /* When the object has the RUNPATH information we don't use any RPATHs. */
2351 if (loader->l_info[DT_RUNPATH] == NULL)
2352 {
2353 /* First try the DT_RPATH of the dependent object that caused NAME
2354 to be loaded. Then that object's dependent, and on up. */
2355
2356 struct link_map *l = loader;
2357 do
2358 {
2359 if (cache_rpath (l, &l->l_rpath_dirs, DT_RPATH, "RPATH"))
2360 add_path (&p, &l->l_rpath_dirs, XXX_RPATH);
2361 l = l->l_loader;
2362 }
2363 while (l != NULL);
2364
2365 /* If dynamically linked, try the DT_RPATH of the executable itself. */
2366 if (loader->l_ns == LM_ID_BASE)
2367 {
2368 l = GL(dl_ns)[LM_ID_BASE]._ns_loaded;
2369 if (l != NULL && l->l_type != lt_loaded && l != loader)
2370 if (cache_rpath (l, &l->l_rpath_dirs, DT_RPATH, "RPATH"))
2371 add_path (&p, &l->l_rpath_dirs, XXX_RPATH);
2372 }
2373 }
2374
2375 /* Try the LD_LIBRARY_PATH environment variable. */
2376 add_path (&p, &__rtld_env_path_list, XXX_ENV);
2377
2378 /* Look at the RUNPATH information for this binary. */
2379 if (cache_rpath (loader, &loader->l_runpath_dirs, DT_RUNPATH, "RUNPATH"))
2380 add_path (&p, &loader->l_runpath_dirs, XXX_RUNPATH);
2381
2382 /* XXX
2383 Here is where ld.so.cache gets checked, but we don't have
2384 a way to indicate that in the results for Dl_serinfo. */
2385
2386 /* Finally, try the default path. */
2387 if (!(loader->l_flags_1 & DF_1_NODEFLIB))
2388 add_path (&p, &__rtld_search_dirs, XXX_default);
2389
2390 if (counting)
2391 /* Count the struct size before the string area, which we didn't
2392 know before we completed dls_cnt. */
2393 si->dls_size += (char *) &si->dls_serpath[si->dls_cnt] - (char *) si;
2394 }
2395