1 /* Map in a shared object's segments from the file.
2 Copyright (C) 1995-2019 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
28 #include <bits/wordsize.h>
30 #include <sys/param.h>
32 #include <sys/types.h>
34 /* Type for the buffer we put the ELF header and hopefully the program
35 header. This buffer does not really have to be too large. In most
36 cases the program header follows the ELF header directly. If this
37 is not the case all bets are off and we can make the header
38 arbitrarily large and still won't get it read. This means the only
39 question is how large are the ELF and program header combined. The
40 ELF header 32-bit files is 52 bytes long and in 64-bit files is 64
41 bytes long. Each program header entry is again 32 and 56 bytes
42 long respectively. I.e., even with a file which has 10 program
43 header entries we only have to read 372B/624B respectively. Add to
44 this a bit of margin for program notes and reading 512B and 832B
45 for 32-bit and 64-bit files respecitvely is enough. If this
46 heuristic should really fail for some file the code in
47 `_dl_map_object_from_fd' knows how to recover. */
52 # define FILEBUF_SIZE 512
54 # define FILEBUF_SIZE 832
56 char buf
[FILEBUF_SIZE
] __attribute__ ((aligned (__alignof (ElfW(Ehdr
)))));
59 #include "dynamic-link.h"
61 #include <stackinfo.h>
63 #include <stap-probe.h>
64 #include <libc-pointer-arith.h>
65 #include <array_length.h>
69 #include <dl-map-segments.h>
70 #include <dl-unmap-segments.h>
71 #include <dl-machine-reject-phdr.h>
72 #include <dl-sysdep-open.h>
74 #include <not-cancel.h>
77 #if BYTE_ORDER == BIG_ENDIAN
78 # define byteorder ELFDATA2MSB
79 #elif BYTE_ORDER == LITTLE_ENDIAN
80 # define byteorder ELFDATA2LSB
82 # error "Unknown BYTE_ORDER " BYTE_ORDER
83 # define byteorder ELFDATANONE
86 #define STRING(x) __STRING (x)
89 int __stack_prot attribute_hidden attribute_relro
90 #if _STACK_GROWS_DOWN && defined PROT_GROWSDOWN
92 #elif _STACK_GROWS_UP && defined PROT_GROWSUP
99 /* This is the decomposed LD_LIBRARY_PATH search path. */
100 static struct r_search_path_struct env_path_list attribute_relro
;
102 /* List of the hardware capabilities we might end up using. */
103 static const struct r_strlenpair
*capstr attribute_relro
;
104 static size_t ncapstr attribute_relro
;
105 static size_t max_capstrlen attribute_relro
;
108 /* Get the generated information about the trusted directories. Use
109 an array of concatenated strings to avoid relocations. See
110 gen-trusted-dirs.awk. */
111 #include "trusted-dirs.h"
113 static const char system_dirs
[] = SYSTEM_DIRS
;
114 static const size_t system_dirs_len
[] =
118 #define nsystem_dirs_len array_length (system_dirs_len)
121 is_trusted_path_normalize (const char *path
, size_t len
)
126 char *npath
= (char *) alloca (len
+ 2);
128 while (*path
!= '\0')
134 if (path
[2] == '.' && (path
[3] == '/' || path
[3] == '\0'))
136 while (wnp
> npath
&& *--wnp
!= '/')
141 else if (path
[2] == '/' || path
[2] == '\0')
148 if (wnp
> npath
&& wnp
[-1] == '/')
158 if (wnp
== npath
|| wnp
[-1] != '/')
161 const char *trun
= system_dirs
;
163 for (size_t idx
= 0; idx
< nsystem_dirs_len
; ++idx
)
165 if (wnp
- npath
>= system_dirs_len
[idx
]
166 && memcmp (trun
, npath
, system_dirs_len
[idx
]) == 0)
170 trun
+= system_dirs_len
[idx
] + 1;
176 /* Given a substring starting at INPUT, just after the DST '$' start
177 token, determine if INPUT contains DST token REF, following the
178 ELF gABI rules for DSTs:
180 * Longest possible sequence using the rules (greedy).
182 * Must start with a $ (enforced by caller).
184 * Must follow $ with one underscore or ASCII [A-Za-z] (caller
185 follows these rules for REF) or '{' (start curly quoted name).
187 * Must follow first two characters with zero or more [A-Za-z0-9_]
188 (enforced by caller) or '}' (end curly quoted name).
190 If the sequence is a DST matching REF then the length of the DST
191 (excluding the $ sign but including curly braces, if any) is
192 returned, otherwise 0. */
194 is_dst (const char *input
, const char *ref
)
196 bool is_curly
= false;
198 /* Is a ${...} input sequence? */
205 /* Check for matching name, following closing curly brace (if
206 required), or trailing characters which are part of an
208 size_t rlen
= strlen (ref
);
209 if (strncmp (input
, ref
, rlen
) != 0
210 || (is_curly
&& input
[rlen
] != '}')
211 || ((input
[rlen
] >= 'A' && input
[rlen
] <= 'Z')
212 || (input
[rlen
] >= 'a' && input
[rlen
] <= 'z')
213 || (input
[rlen
] >= '0' && input
[rlen
] <= '9')
214 || (input
[rlen
] == '_')))
218 /* Count the two curly braces. */
224 /* INPUT should be the start of a path e.g DT_RPATH or name e.g.
225 DT_NEEDED. The return value is the number of known DSTs found. We
226 count all known DSTs regardless of __libc_enable_secure; the caller
227 is responsible for enforcing the security of the substitution rules
228 (usually _dl_dst_substitute). */
230 _dl_dst_count (const char *input
)
234 input
= strchr (input
, '$');
236 /* Most likely there is no DST. */
237 if (__glibc_likely (input
== NULL
))
245 /* All DSTs must follow ELF gABI rules, see is_dst (). */
246 if ((len
= is_dst (input
, "ORIGIN")) != 0
247 || (len
= is_dst (input
, "PLATFORM")) != 0
248 || (len
= is_dst (input
, "LIB")) != 0)
251 /* There may be more than one DST in the input. */
252 input
= strchr (input
+ len
, '$');
254 while (input
!= NULL
);
259 /* Process INPUT for DSTs and store in RESULT using the information
260 from link map L to resolve the DSTs. This function only handles one
261 path at a time and does not handle colon-separated path lists (see
262 fillin_rpath ()). Lastly the size of result in bytes should be at
263 least equal to the value returned by DL_DST_REQUIRED. Note that it
264 is possible for a DT_NEEDED, DT_AUXILIARY, and DT_FILTER entries to
265 have colons, but we treat those as literal colons here, not as path
268 _dl_dst_substitute (struct link_map
*l
, const char *input
, char *result
)
270 /* Copy character-by-character from input into the working pointer
271 looking for any DSTs. We track the start of input and if we are
272 going to check for trusted paths, all of which are part of $ORIGIN
273 handling in SUID/SGID cases (see below). In some cases, like when
274 a DST cannot be replaced, we may set result to an empty string and
277 const char *start
= input
;
278 bool check_for_trusted
= false;
282 if (__glibc_unlikely (*input
== '$'))
284 const char *repl
= NULL
;
288 if ((len
= is_dst (input
, "ORIGIN")) != 0)
290 /* For SUID/GUID programs we normally ignore the path with
291 $ORIGIN in DT_RUNPATH, or DT_RPATH. However, there is
292 one exception to this rule, and it is:
294 * $ORIGIN appears as the first path element, and is
295 the only string in the path or is immediately
296 followed by a path separator and the rest of the
301 * The path is rooted in a trusted directory.
303 This exception allows such programs to reference
304 shared libraries in subdirectories of trusted
305 directories. The use case is one of general
306 organization and deployment flexibility.
307 Trusted directories are usually such paths as "/lib64"
308 or "/usr/lib64", and the usual RPATHs take the form of
309 [$ORIGIN/../$LIB/somedir]. */
310 if (__glibc_unlikely (__libc_enable_secure
)
311 && !(input
== start
+ 1
312 && (input
[len
] == '\0' || input
[len
] == '/')))
313 repl
= (const char *) -1;
317 check_for_trusted
= (__libc_enable_secure
318 && l
->l_type
== lt_executable
);
320 else if ((len
= is_dst (input
, "PLATFORM")) != 0)
321 repl
= GLRO(dl_platform
);
322 else if ((len
= is_dst (input
, "LIB")) != 0)
325 if (repl
!= NULL
&& repl
!= (const char *) -1)
327 wp
= __stpcpy (wp
, repl
);
332 /* We found a valid DST that we know about, but we could
333 not find a replacement value for it, therefore we
334 cannot use this path and discard it. */
339 /* No DST we recognize. */
347 while (*input
!= '\0');
349 /* In SUID/SGID programs, after $ORIGIN expansion the normalized
350 path must be rooted in one of the trusted directories. The $LIB
351 and $PLATFORM DST cannot in any way be manipulated by the caller
352 because they are fixed values that are set by the dynamic loader
353 and therefore any paths using just $LIB or $PLATFORM need not be
354 checked for trust, the authors of the binaries themselves are
355 trusted to have designed this correctly. Only $ORIGIN is tested in
356 this way because it may be manipulated in some ways with hard
358 if (__glibc_unlikely (check_for_trusted
)
359 && !is_trusted_path_normalize (result
, wp
- result
))
371 /* Return a malloc allocated copy of INPUT with all recognized DSTs
372 replaced. On some platforms it might not be possible to determine the
373 path from which the object belonging to the map is loaded. In this
374 case the path containing the DST is left out. On error NULL
377 expand_dynamic_string_token (struct link_map
*l
, const char *input
)
379 /* We make two runs over the string. First we determine how large the
380 resulting string is and then we copy it over. Since this is no
381 frequently executed operation we are looking here not for performance
382 but rather for code size. */
387 /* Determine the number of DSTs. */
388 cnt
= _dl_dst_count (input
);
390 /* If we do not have to replace anything simply copy the string. */
391 if (__glibc_likely (cnt
== 0))
392 return __strdup (input
);
394 /* Determine the length of the substituted string. */
395 total
= DL_DST_REQUIRED (l
, input
, strlen (input
), cnt
);
397 /* Allocate the necessary memory. */
398 result
= (char *) malloc (total
+ 1);
402 return _dl_dst_substitute (l
, input
, result
);
406 /* Add `name' to the list of names for a particular shared object.
407 `name' is expected to have been allocated with malloc and will
408 be freed if the shared object already has this name.
409 Returns false if the object already had this name. */
411 add_name_to_object (struct link_map
*l
, const char *name
)
413 struct libname_list
*lnp
, *lastp
;
414 struct libname_list
*newname
;
418 for (lnp
= l
->l_libname
; lnp
!= NULL
; lastp
= lnp
, lnp
= lnp
->next
)
419 if (strcmp (name
, lnp
->name
) == 0)
422 name_len
= strlen (name
) + 1;
423 newname
= (struct libname_list
*) malloc (sizeof *newname
+ name_len
);
426 /* No more memory. */
427 _dl_signal_error (ENOMEM
, name
, NULL
, N_("cannot allocate name record"));
430 /* The object should have a libname set from _dl_new_object. */
431 assert (lastp
!= NULL
);
433 newname
->name
= memcpy (newname
+ 1, name
, name_len
);
434 newname
->next
= NULL
;
435 newname
->dont_free
= 0;
436 lastp
->next
= newname
;
439 /* Standard search directories. */
440 static struct r_search_path_struct rtld_search_dirs attribute_relro
;
442 static size_t max_dirnamelen
;
444 static struct r_search_path_elem
**
445 fillin_rpath (char *rpath
, struct r_search_path_elem
**result
, const char *sep
,
446 const char *what
, const char *where
, struct link_map
*l
)
451 while ((cp
= __strsep (&rpath
, sep
)) != NULL
)
453 struct r_search_path_elem
*dirp
;
454 char *to_free
= NULL
;
457 /* `strsep' can pass an empty string. */
460 to_free
= cp
= expand_dynamic_string_token (l
, cp
);
462 /* expand_dynamic_string_token can return NULL in case of empty
463 path or memory allocation failure. */
467 /* Compute the length after dynamic string token expansion and
468 ignore empty paths. */
476 /* Remove trailing slashes (except for "/"). */
477 while (len
> 1 && cp
[len
- 1] == '/')
480 /* Now add one if there is none so far. */
481 if (len
> 0 && cp
[len
- 1] != '/')
485 /* See if this directory is already known. */
486 for (dirp
= GL(dl_all_dirs
); dirp
!= NULL
; dirp
= dirp
->next
)
487 if (dirp
->dirnamelen
== len
&& memcmp (cp
, dirp
->dirname
, len
) == 0)
492 /* It is available, see whether it's on our own list. */
494 for (cnt
= 0; cnt
< nelems
; ++cnt
)
495 if (result
[cnt
] == dirp
)
499 result
[nelems
++] = dirp
;
504 enum r_dir_status init_val
;
505 size_t where_len
= where
? strlen (where
) + 1 : 0;
507 /* It's a new directory. Create an entry and add it. */
508 dirp
= (struct r_search_path_elem
*)
509 malloc (sizeof (*dirp
) + ncapstr
* sizeof (enum r_dir_status
)
510 + where_len
+ len
+ 1);
512 _dl_signal_error (ENOMEM
, NULL
, NULL
,
513 N_("cannot create cache for search path"));
515 dirp
->dirname
= ((char *) dirp
+ sizeof (*dirp
)
516 + ncapstr
* sizeof (enum r_dir_status
));
517 *((char *) __mempcpy ((char *) dirp
->dirname
, cp
, len
)) = '\0';
518 dirp
->dirnamelen
= len
;
520 if (len
> max_dirnamelen
)
521 max_dirnamelen
= len
;
523 /* We have to make sure all the relative directories are
524 never ignored. The current directory might change and
525 all our saved information would be void. */
526 init_val
= cp
[0] != '/' ? existing
: unknown
;
527 for (cnt
= 0; cnt
< ncapstr
; ++cnt
)
528 dirp
->status
[cnt
] = init_val
;
531 if (__glibc_likely (where
!= NULL
))
532 dirp
->where
= memcpy ((char *) dirp
+ sizeof (*dirp
) + len
+ 1
533 + (ncapstr
* sizeof (enum r_dir_status
)),
538 dirp
->next
= GL(dl_all_dirs
);
539 GL(dl_all_dirs
) = dirp
;
541 /* Put it in the result array. */
542 result
[nelems
++] = dirp
;
547 /* Terminate the array. */
548 result
[nelems
] = NULL
;
555 decompose_rpath (struct r_search_path_struct
*sps
,
556 const char *rpath
, struct link_map
*l
, const char *what
)
558 /* Make a copy we can work with. */
559 const char *where
= l
->l_name
;
561 struct r_search_path_elem
**result
;
563 /* Initialize to please the compiler. */
564 const char *errstring
= NULL
;
566 /* First see whether we must forget the RUNPATH and RPATH from this
568 if (__glibc_unlikely (GLRO(dl_inhibit_rpath
) != NULL
)
569 && !__libc_enable_secure
)
571 const char *inhp
= GLRO(dl_inhibit_rpath
);
575 const char *wp
= where
;
577 while (*inhp
== *wp
&& *wp
!= '\0')
583 if (*wp
== '\0' && (*inhp
== '\0' || *inhp
== ':'))
585 /* This object is on the list of objects for which the
586 RUNPATH and RPATH must not be used. */
587 sps
->dirs
= (void *) -1;
591 while (*inhp
!= '\0')
595 while (*inhp
!= '\0');
598 /* Ignore empty rpaths. */
601 sps
->dirs
= (struct r_search_path_elem
**) -1;
605 /* Make a writable copy. */
606 char *copy
= __strdup (rpath
);
609 errstring
= N_("cannot create RUNPATH/RPATH copy");
613 /* Count the number of necessary elements in the result array. */
615 for (cp
= copy
; *cp
!= '\0'; ++cp
)
619 /* Allocate room for the result. NELEMS + 1 is an upper limit for the
620 number of necessary entries. */
621 result
= (struct r_search_path_elem
**) malloc ((nelems
+ 1 + 1)
626 errstring
= N_("cannot create cache for search path");
628 _dl_signal_error (ENOMEM
, NULL
, NULL
, errstring
);
631 fillin_rpath (copy
, result
, ":", what
, where
, l
);
633 /* Free the copied RPATH string. `fillin_rpath' make own copies if
637 /* There is no path after expansion. */
638 if (result
[0] == NULL
)
641 sps
->dirs
= (struct r_search_path_elem
**) -1;
646 /* The caller will change this value if we haven't used a real malloc. */
651 /* Make sure cached path information is stored in *SP
652 and return true if there are any paths to search there. */
654 cache_rpath (struct link_map
*l
,
655 struct r_search_path_struct
*sp
,
659 if (sp
->dirs
== (void *) -1)
662 if (sp
->dirs
!= NULL
)
665 if (l
->l_info
[tag
] == NULL
)
667 /* There is no path. */
668 sp
->dirs
= (void *) -1;
672 /* Make sure the cache information is available. */
673 return decompose_rpath (sp
, (const char *) (D_PTR (l
, l_info
[DT_STRTAB
])
674 + l
->l_info
[tag
]->d_un
.d_val
),
680 _dl_init_paths (const char *llp
)
684 struct r_search_path_elem
*pelem
, **aelem
;
686 struct link_map
__attribute__ ((unused
)) *l
= NULL
;
687 /* Initialize to please the compiler. */
688 const char *errstring
= NULL
;
690 /* Fill in the information about the application's RPATH and the
691 directories addressed by the LD_LIBRARY_PATH environment variable. */
693 /* Get the capabilities. */
694 capstr
= _dl_important_hwcaps (GLRO(dl_platform
), GLRO(dl_platformlen
),
695 &ncapstr
, &max_capstrlen
);
697 /* First set up the rest of the default search directory entries. */
698 aelem
= rtld_search_dirs
.dirs
= (struct r_search_path_elem
**)
699 malloc ((nsystem_dirs_len
+ 1) * sizeof (struct r_search_path_elem
*));
700 if (rtld_search_dirs
.dirs
== NULL
)
702 errstring
= N_("cannot create search path array");
704 _dl_signal_error (ENOMEM
, NULL
, NULL
, errstring
);
707 round_size
= ((2 * sizeof (struct r_search_path_elem
) - 1
708 + ncapstr
* sizeof (enum r_dir_status
))
709 / sizeof (struct r_search_path_elem
));
711 rtld_search_dirs
.dirs
[0] = malloc (nsystem_dirs_len
* round_size
712 * sizeof (*rtld_search_dirs
.dirs
[0]));
713 if (rtld_search_dirs
.dirs
[0] == NULL
)
715 errstring
= N_("cannot create cache for search path");
719 rtld_search_dirs
.malloced
= 0;
720 pelem
= GL(dl_all_dirs
) = rtld_search_dirs
.dirs
[0];
730 pelem
->what
= "system search path";
733 pelem
->dirname
= strp
;
734 pelem
->dirnamelen
= system_dirs_len
[idx
];
735 strp
+= system_dirs_len
[idx
] + 1;
737 /* System paths must be absolute. */
738 assert (pelem
->dirname
[0] == '/');
739 for (cnt
= 0; cnt
< ncapstr
; ++cnt
)
740 pelem
->status
[cnt
] = unknown
;
742 pelem
->next
= (++idx
== nsystem_dirs_len
? NULL
: (pelem
+ round_size
));
746 while (idx
< nsystem_dirs_len
);
748 max_dirnamelen
= SYSTEM_DIRS_MAX_LEN
;
752 /* This points to the map of the main object. */
753 l
= GL(dl_ns
)[LM_ID_BASE
]._ns_loaded
;
756 assert (l
->l_type
!= lt_loaded
);
758 if (l
->l_info
[DT_RUNPATH
])
760 /* Allocate room for the search path and fill in information
762 decompose_rpath (&l
->l_runpath_dirs
,
763 (const void *) (D_PTR (l
, l_info
[DT_STRTAB
])
764 + l
->l_info
[DT_RUNPATH
]->d_un
.d_val
),
766 /* During rtld init the memory is allocated by the stub malloc,
767 prevent any attempt to free it by the normal malloc. */
768 l
->l_runpath_dirs
.malloced
= 0;
770 /* The RPATH is ignored. */
771 l
->l_rpath_dirs
.dirs
= (void *) -1;
775 l
->l_runpath_dirs
.dirs
= (void *) -1;
777 if (l
->l_info
[DT_RPATH
])
779 /* Allocate room for the search path and fill in information
781 decompose_rpath (&l
->l_rpath_dirs
,
782 (const void *) (D_PTR (l
, l_info
[DT_STRTAB
])
783 + l
->l_info
[DT_RPATH
]->d_un
.d_val
),
785 /* During rtld init the memory is allocated by the stub
786 malloc, prevent any attempt to free it by the normal
788 l
->l_rpath_dirs
.malloced
= 0;
791 l
->l_rpath_dirs
.dirs
= (void *) -1;
796 if (llp
!= NULL
&& *llp
!= '\0')
798 char *llp_tmp
= strdupa (llp
);
800 /* Decompose the LD_LIBRARY_PATH contents. First determine how many
803 for (const char *cp
= llp_tmp
; *cp
!= '\0'; ++cp
)
804 if (*cp
== ':' || *cp
== ';')
807 env_path_list
.dirs
= (struct r_search_path_elem
**)
808 malloc ((nllp
+ 1) * sizeof (struct r_search_path_elem
*));
809 if (env_path_list
.dirs
== NULL
)
811 errstring
= N_("cannot create cache for search path");
815 (void) fillin_rpath (llp_tmp
, env_path_list
.dirs
, ":;",
816 "LD_LIBRARY_PATH", NULL
, l
);
818 if (env_path_list
.dirs
[0] == NULL
)
820 free (env_path_list
.dirs
);
821 env_path_list
.dirs
= (void *) -1;
824 env_path_list
.malloced
= 0;
827 env_path_list
.dirs
= (void *) -1;
832 __attribute__ ((noreturn
, noinline
))
833 lose (int code
, int fd
, const char *name
, char *realname
, struct link_map
*l
,
834 const char *msg
, struct r_debug
*r
, Lmid_t nsid
)
836 /* The file might already be closed. */
838 (void) __close_nocancel (fd
);
839 if (l
!= NULL
&& l
->l_origin
!= (char *) -1l)
840 free ((char *) l
->l_origin
);
846 r
->r_state
= RT_CONSISTENT
;
848 LIBC_PROBE (map_failed
, 2, nsid
, r
);
851 _dl_signal_error (code
, name
, NULL
, msg
);
855 /* Map in the shared object NAME, actually located in REALNAME, and already
858 #ifndef EXTERNAL_MAP_FROM_FD
862 _dl_map_object_from_fd (const char *name
, const char *origname
, int fd
,
863 struct filebuf
*fbp
, char *realname
,
864 struct link_map
*loader
, int l_type
, int mode
,
865 void **stack_endp
, Lmid_t nsid
)
867 struct link_map
*l
= NULL
;
868 const ElfW(Ehdr
) *header
;
869 const ElfW(Phdr
) *phdr
;
870 const ElfW(Phdr
) *ph
;
873 /* Initialize to keep the compiler happy. */
874 const char *errstring
= NULL
;
876 struct r_debug
*r
= _dl_debug_initialize (0, nsid
);
877 bool make_consistent
= false;
879 /* Get file information. To match the kernel behavior, do not fill
880 in this information for the executable in case of an explicit
881 loader invocation. */
883 if (mode
& __RTLD_OPENEXEC
)
885 assert (nsid
== LM_ID_BASE
);
886 memset (&id
, 0, sizeof (id
));
890 if (__glibc_unlikely (!_dl_get_file_id (fd
, &id
)))
892 errstring
= N_("cannot stat shared object");
896 lose (errval
, fd
, name
, realname
, l
, errstring
,
897 make_consistent
? r
: NULL
, nsid
);
900 /* Look again to see if the real name matched another already loaded. */
901 for (l
= GL(dl_ns
)[nsid
]._ns_loaded
; l
!= NULL
; l
= l
->l_next
)
902 if (!l
->l_removed
&& _dl_file_id_match_p (&l
->l_file_id
, &id
))
904 /* The object is already loaded.
905 Just bump its reference count and return it. */
906 __close_nocancel (fd
);
908 /* If the name is not in the list of names for this object add
911 add_name_to_object (l
, name
);
918 /* When loading into a namespace other than the base one we must
919 avoid loading ld.so since there can only be one copy. Ever. */
920 if (__glibc_unlikely (nsid
!= LM_ID_BASE
)
921 && (_dl_file_id_match_p (&id
, &GL(dl_rtld_map
).l_file_id
)
922 || _dl_name_match_p (name
, &GL(dl_rtld_map
))))
924 /* This is indeed ld.so. Create a new link_map which refers to
925 the real one for almost everything. */
926 l
= _dl_new_object (realname
, name
, l_type
, loader
, mode
, nsid
);
930 /* Refer to the real descriptor. */
931 l
->l_real
= &GL(dl_rtld_map
);
933 /* No need to bump the refcount of the real object, ld.so will
934 never be unloaded. */
935 __close_nocancel (fd
);
937 /* Add the map for the mirrored object to the object list. */
938 _dl_add_to_namespace_list (l
, nsid
);
944 if (mode
& RTLD_NOLOAD
)
946 /* We are not supposed to load the object unless it is already
947 loaded. So return now. */
949 __close_nocancel (fd
);
953 /* Print debugging message. */
954 if (__glibc_unlikely (GLRO(dl_debug_mask
) & DL_DEBUG_FILES
))
955 _dl_debug_printf ("file=%s [%lu]; generating link map\n", name
, nsid
);
957 /* This is the ELF header. We read it in `open_verify'. */
958 header
= (void *) fbp
->buf
;
960 /* Signal that we are going to add new objects. */
961 if (r
->r_state
== RT_CONSISTENT
)
964 /* Auditing checkpoint: we are going to add new objects. */
965 if ((mode
& __RTLD_AUDIT
) == 0
966 && __glibc_unlikely (GLRO(dl_naudit
) > 0))
968 struct link_map
*head
= GL(dl_ns
)[nsid
]._ns_loaded
;
969 /* Do not call the functions for any auditing object. */
970 if (head
->l_auditing
== 0)
972 struct audit_ifaces
*afct
= GLRO(dl_audit
);
973 for (unsigned int cnt
= 0; cnt
< GLRO(dl_naudit
); ++cnt
)
975 if (afct
->activity
!= NULL
)
976 afct
->activity (&head
->l_audit
[cnt
].cookie
, LA_ACT_ADD
);
984 /* Notify the debugger we have added some objects. We need to
985 call _dl_debug_initialize in a static program in case dynamic
986 linking has not been used before. */
989 LIBC_PROBE (map_start
, 2, nsid
, r
);
990 make_consistent
= true;
993 assert (r
->r_state
== RT_ADD
);
995 /* Enter the new object in the list of loaded objects. */
996 l
= _dl_new_object (realname
, name
, l_type
, loader
, mode
, nsid
);
997 if (__glibc_unlikely (l
== NULL
))
1002 errstring
= N_("cannot create shared object descriptor");
1003 goto call_lose_errno
;
1006 /* Extract the remaining details we need from the ELF header
1007 and then read in the program header table. */
1008 l
->l_entry
= header
->e_entry
;
1009 type
= header
->e_type
;
1010 l
->l_phnum
= header
->e_phnum
;
1012 maplength
= header
->e_phnum
* sizeof (ElfW(Phdr
));
1013 if (header
->e_phoff
+ maplength
<= (size_t) fbp
->len
)
1014 phdr
= (void *) (fbp
->buf
+ header
->e_phoff
);
1017 phdr
= alloca (maplength
);
1018 if ((size_t) __pread64_nocancel (fd
, (void *) phdr
, maplength
,
1019 header
->e_phoff
) != maplength
)
1021 errstring
= N_("cannot read file data");
1022 goto call_lose_errno
;
1026 /* On most platforms presume that PT_GNU_STACK is absent and the stack is
1027 * executable. Other platforms default to a nonexecutable stack and don't
1028 * need PT_GNU_STACK to do so. */
1029 uint_fast16_t stack_flags
= DEFAULT_STACK_PERMS
;
1032 /* Scan the program header table, collecting its load commands. */
1033 struct loadcmd loadcmds
[l
->l_phnum
];
1034 size_t nloadcmds
= 0;
1035 bool has_holes
= false;
1037 /* The struct is initialized to zero so this is not necessary:
1041 for (ph
= phdr
; ph
< &phdr
[l
->l_phnum
]; ++ph
)
1044 /* These entries tell us where to find things once the file's
1045 segments are mapped in. We record the addresses it says
1046 verbatim, and later correct for the run-time load address. */
1050 /* Debuginfo only files from "objcopy --only-keep-debug"
1051 contain a PT_DYNAMIC segment with p_filesz == 0. Skip
1052 such a segment to avoid a crash later. */
1053 l
->l_ld
= (void *) ph
->p_vaddr
;
1054 l
->l_ldnum
= ph
->p_memsz
/ sizeof (ElfW(Dyn
));
1059 l
->l_phdr
= (void *) ph
->p_vaddr
;
1063 /* A load command tells us to map in part of the file.
1064 We record the load commands and process them all later. */
1065 if (__glibc_unlikely ((ph
->p_align
& (GLRO(dl_pagesize
) - 1)) != 0))
1067 errstring
= N_("ELF load command alignment not page-aligned");
1070 if (__glibc_unlikely (((ph
->p_vaddr
- ph
->p_offset
)
1071 & (ph
->p_align
- 1)) != 0))
1074 = N_("ELF load command address/offset not properly aligned");
1078 struct loadcmd
*c
= &loadcmds
[nloadcmds
++];
1079 c
->mapstart
= ALIGN_DOWN (ph
->p_vaddr
, GLRO(dl_pagesize
));
1080 c
->mapend
= ALIGN_UP (ph
->p_vaddr
+ ph
->p_filesz
, GLRO(dl_pagesize
));
1081 c
->dataend
= ph
->p_vaddr
+ ph
->p_filesz
;
1082 c
->allocend
= ph
->p_vaddr
+ ph
->p_memsz
;
1083 c
->mapoff
= ALIGN_DOWN (ph
->p_offset
, GLRO(dl_pagesize
));
1085 /* Determine whether there is a gap between the last segment
1087 if (nloadcmds
> 1 && c
[-1].mapend
!= c
->mapstart
)
1090 /* Optimize a common case. */
1091 #if (PF_R | PF_W | PF_X) == 7 && (PROT_READ | PROT_WRITE | PROT_EXEC) == 7
1092 c
->prot
= (PF_TO_PROT
1093 >> ((ph
->p_flags
& (PF_R
| PF_W
| PF_X
)) * 4)) & 0xf;
1096 if (ph
->p_flags
& PF_R
)
1097 c
->prot
|= PROT_READ
;
1098 if (ph
->p_flags
& PF_W
)
1099 c
->prot
|= PROT_WRITE
;
1100 if (ph
->p_flags
& PF_X
)
1101 c
->prot
|= PROT_EXEC
;
1106 if (ph
->p_memsz
== 0)
1107 /* Nothing to do for an empty segment. */
1110 l
->l_tls_blocksize
= ph
->p_memsz
;
1111 l
->l_tls_align
= ph
->p_align
;
1112 if (ph
->p_align
== 0)
1113 l
->l_tls_firstbyte_offset
= 0;
1115 l
->l_tls_firstbyte_offset
= ph
->p_vaddr
& (ph
->p_align
- 1);
1116 l
->l_tls_initimage_size
= ph
->p_filesz
;
1117 /* Since we don't know the load address yet only store the
1118 offset. We will adjust it later. */
1119 l
->l_tls_initimage
= (void *) ph
->p_vaddr
;
1121 /* l->l_tls_modid is assigned below, once there is no
1122 possibility for failure. */
1124 if (l
->l_type
!= lt_library
1125 && GL(dl_tls_dtv_slotinfo_list
) == NULL
)
1128 /* We are loading the executable itself when the dynamic
1129 linker was executed directly. The setup will happen
1131 assert (l
->l_prev
== NULL
|| (mode
& __RTLD_AUDIT
) != 0);
1133 assert (false && "TLS not initialized in static application");
1139 stack_flags
= ph
->p_flags
;
1143 l
->l_relro_addr
= ph
->p_vaddr
;
1144 l
->l_relro_size
= ph
->p_memsz
;
1148 if (_dl_process_pt_note (l
, ph
, fd
, fbp
))
1150 errstring
= N_("cannot process note segment");
1156 if (__glibc_unlikely (nloadcmds
== 0))
1158 /* This only happens for a bogus object that will be caught with
1159 another error below. But we don't want to go through the
1160 calculations below using NLOADCMDS - 1. */
1161 errstring
= N_("object file has no loadable segments");
1165 /* dlopen of an executable is not valid because it is not possible
1166 to perform proper relocations, handle static TLS, or run the
1167 ELF constructors. For PIE, the check needs the dynamic
1168 section, so there is another check below. */
1169 if (__glibc_unlikely (type
!= ET_DYN
)
1170 && __glibc_unlikely ((mode
& __RTLD_OPENEXEC
) == 0))
1172 /* This object is loaded at a fixed address. This must never
1173 happen for objects loaded with dlopen. */
1174 errstring
= N_("cannot dynamically load executable");
1178 /* Length of the sections to be loaded. */
1179 maplength
= loadcmds
[nloadcmds
- 1].allocend
- loadcmds
[0].mapstart
;
1181 /* Now process the load commands and map segments into memory.
1182 This is responsible for filling in:
1183 l_map_start, l_map_end, l_addr, l_contiguous, l_text_end, l_phdr
1185 errstring
= _dl_map_segments (l
, fd
, header
, type
, loadcmds
, nloadcmds
,
1186 maplength
, has_holes
, loader
);
1187 if (__glibc_unlikely (errstring
!= NULL
))
1193 if (__glibc_unlikely (type
== ET_DYN
))
1195 errstring
= N_("object file has no dynamic section");
1200 l
->l_ld
= (ElfW(Dyn
) *) ((ElfW(Addr
)) l
->l_ld
+ l
->l_addr
);
1202 elf_get_dynamic_info (l
, NULL
);
1204 /* Make sure we are not dlopen'ing an object that has the
1205 DF_1_NOOPEN flag set, or a PIE object. */
1206 if ((__glibc_unlikely (l
->l_flags_1
& DF_1_NOOPEN
)
1207 && (mode
& __RTLD_DLOPEN
))
1208 || (__glibc_unlikely (l
->l_flags_1
& DF_1_PIE
)
1209 && __glibc_unlikely ((mode
& __RTLD_OPENEXEC
) == 0)))
1211 /* We are not supposed to load this object. Free all resources. */
1212 _dl_unmap_segments (l
);
1214 if (!l
->l_libname
->dont_free
)
1215 free (l
->l_libname
);
1217 if (l
->l_phdr_allocated
)
1218 free ((void *) l
->l_phdr
);
1220 if (l
->l_flags_1
& DF_1_PIE
)
1222 = N_("cannot dynamically load position-independent executable");
1224 errstring
= N_("shared object cannot be dlopen()ed");
1228 if (l
->l_phdr
== NULL
)
1230 /* The program header is not contained in any of the segments.
1231 We have to allocate memory ourself and copy it over from out
1233 ElfW(Phdr
) *newp
= (ElfW(Phdr
) *) malloc (header
->e_phnum
1234 * sizeof (ElfW(Phdr
)));
1237 errstring
= N_("cannot allocate memory for program header");
1238 goto call_lose_errno
;
1241 l
->l_phdr
= memcpy (newp
, phdr
,
1242 (header
->e_phnum
* sizeof (ElfW(Phdr
))));
1243 l
->l_phdr_allocated
= 1;
1246 /* Adjust the PT_PHDR value by the runtime load address. */
1247 l
->l_phdr
= (ElfW(Phdr
) *) ((ElfW(Addr
)) l
->l_phdr
+ l
->l_addr
);
1249 if (__glibc_unlikely ((stack_flags
&~ GL(dl_stack_flags
)) & PF_X
))
1251 /* The stack is presently not executable, but this module
1252 requires that it be executable. We must change the
1253 protection of the variable which contains the flags used in
1254 the mprotect calls. */
1256 if ((mode
& (__RTLD_DLOPEN
| __RTLD_AUDIT
)) == __RTLD_DLOPEN
)
1258 const uintptr_t p
= (uintptr_t) &__stack_prot
& -GLRO(dl_pagesize
);
1259 const size_t s
= (uintptr_t) (&__stack_prot
+ 1) - p
;
1261 struct link_map
*const m
= &GL(dl_rtld_map
);
1262 const uintptr_t relro_end
= ((m
->l_addr
+ m
->l_relro_addr
1264 & -GLRO(dl_pagesize
));
1265 if (__glibc_likely (p
+ s
<= relro_end
))
1267 /* The variable lies in the region protected by RELRO. */
1268 if (__mprotect ((void *) p
, s
, PROT_READ
|PROT_WRITE
) < 0)
1270 errstring
= N_("cannot change memory protections");
1271 goto call_lose_errno
;
1273 __stack_prot
|= PROT_READ
|PROT_WRITE
|PROT_EXEC
;
1274 __mprotect ((void *) p
, s
, PROT_READ
);
1277 __stack_prot
|= PROT_READ
|PROT_WRITE
|PROT_EXEC
;
1281 __stack_prot
|= PROT_READ
|PROT_WRITE
|PROT_EXEC
;
1283 #ifdef check_consistency
1284 check_consistency ();
1287 errval
= (*GL(dl_make_stack_executable_hook
)) (stack_endp
);
1291 cannot enable executable stack as shared object requires");
1296 /* Adjust the address of the TLS initialization image. */
1297 if (l
->l_tls_initimage
!= NULL
)
1298 l
->l_tls_initimage
= (char *) l
->l_tls_initimage
+ l
->l_addr
;
1300 /* We are done mapping in the file. We no longer need the descriptor. */
1301 if (__glibc_unlikely (__close_nocancel (fd
) != 0))
1303 errstring
= N_("cannot close file descriptor");
1304 goto call_lose_errno
;
1306 /* Signal that we closed the file. */
1309 /* If this is ET_EXEC, we should have loaded it as lt_executable. */
1310 assert (type
!= ET_EXEC
|| l
->l_type
== lt_executable
);
1312 l
->l_entry
+= l
->l_addr
;
1314 if (__glibc_unlikely (GLRO(dl_debug_mask
) & DL_DEBUG_FILES
))
1315 _dl_debug_printf ("\
1316 dynamic: 0x%0*lx base: 0x%0*lx size: 0x%0*Zx\n\
1317 entry: 0x%0*lx phdr: 0x%0*lx phnum: %*u\n\n",
1318 (int) sizeof (void *) * 2,
1319 (unsigned long int) l
->l_ld
,
1320 (int) sizeof (void *) * 2,
1321 (unsigned long int) l
->l_addr
,
1322 (int) sizeof (void *) * 2, maplength
,
1323 (int) sizeof (void *) * 2,
1324 (unsigned long int) l
->l_entry
,
1325 (int) sizeof (void *) * 2,
1326 (unsigned long int) l
->l_phdr
,
1327 (int) sizeof (void *) * 2, l
->l_phnum
);
1329 /* Set up the symbol hash table. */
1332 /* If this object has DT_SYMBOLIC set modify now its scope. We don't
1333 have to do this for the main map. */
1334 if ((mode
& RTLD_DEEPBIND
) == 0
1335 && __glibc_unlikely (l
->l_info
[DT_SYMBOLIC
] != NULL
)
1336 && &l
->l_searchlist
!= l
->l_scope
[0])
1338 /* Create an appropriate searchlist. It contains only this map.
1339 This is the definition of DT_SYMBOLIC in SysVr4. */
1340 l
->l_symbolic_searchlist
.r_list
[0] = l
;
1341 l
->l_symbolic_searchlist
.r_nlist
= 1;
1343 /* Now move the existing entries one back. */
1344 memmove (&l
->l_scope
[1], &l
->l_scope
[0],
1345 (l
->l_scope_max
- 1) * sizeof (l
->l_scope
[0]));
1347 /* Now add the new entry. */
1348 l
->l_scope
[0] = &l
->l_symbolic_searchlist
;
1351 /* Remember whether this object must be initialized first. */
1352 if (l
->l_flags_1
& DF_1_INITFIRST
)
1353 GL(dl_initfirst
) = l
;
1355 /* Finally the file information. */
1359 /* When auditing is used the recorded names might not include the
1360 name by which the DSO is actually known. Add that as well. */
1361 if (__glibc_unlikely (origname
!= NULL
))
1362 add_name_to_object (l
, origname
);
1364 /* Audit modules only exist when linking is dynamic so ORIGNAME
1365 cannot be non-NULL. */
1366 assert (origname
== NULL
);
1369 /* When we profile the SONAME might be needed for something else but
1370 loading. Add it right away. */
1371 if (__glibc_unlikely (GLRO(dl_profile
) != NULL
)
1372 && l
->l_info
[DT_SONAME
] != NULL
)
1373 add_name_to_object (l
, ((const char *) D_PTR (l
, l_info
[DT_STRTAB
])
1374 + l
->l_info
[DT_SONAME
]->d_un
.d_val
));
1376 /* _dl_close can only eventually undo the module ID assignment (via
1377 remove_slotinfo) if this function returns a pointer to a link
1378 map. Therefore, delay this step until all possibilities for
1379 failure have been excluded. */
1380 if (l
->l_tls_blocksize
> 0
1381 && (__glibc_likely (l
->l_type
== lt_library
)
1382 /* If GL(dl_tls_dtv_slotinfo_list) == NULL, then rtld.c did
1383 not set up TLS data structures, so don't use them now. */
1384 || __glibc_likely (GL(dl_tls_dtv_slotinfo_list
) != NULL
)))
1385 /* Assign the next available module ID. */
1386 l
->l_tls_modid
= _dl_next_tls_modid ();
1388 #ifdef DL_AFTER_LOAD
1392 /* Now that the object is fully initialized add it to the object list. */
1393 _dl_add_to_namespace_list (l
, nsid
);
1396 /* Auditing checkpoint: we have a new object. */
1397 if (__glibc_unlikely (GLRO(dl_naudit
) > 0)
1398 && !GL(dl_ns
)[l
->l_ns
]._ns_loaded
->l_auditing
)
1400 struct audit_ifaces
*afct
= GLRO(dl_audit
);
1401 for (unsigned int cnt
= 0; cnt
< GLRO(dl_naudit
); ++cnt
)
1403 if (afct
->objopen
!= NULL
)
1405 l
->l_audit
[cnt
].bindflags
1406 = afct
->objopen (l
, nsid
, &l
->l_audit
[cnt
].cookie
);
1408 l
->l_audit_any_plt
|= l
->l_audit
[cnt
].bindflags
!= 0;
1419 /* Print search path. */
1421 print_search_path (struct r_search_path_elem
**list
,
1422 const char *what
, const char *name
)
1424 char buf
[max_dirnamelen
+ max_capstrlen
];
1427 _dl_debug_printf (" search path=");
1429 while (*list
!= NULL
&& (*list
)->what
== what
) /* Yes, ==. */
1431 char *endp
= __mempcpy (buf
, (*list
)->dirname
, (*list
)->dirnamelen
);
1434 for (cnt
= 0; cnt
< ncapstr
; ++cnt
)
1435 if ((*list
)->status
[cnt
] != nonexisting
)
1437 char *cp
= __mempcpy (endp
, capstr
[cnt
].str
, capstr
[cnt
].len
);
1438 if (cp
== buf
|| (cp
== buf
+ 1 && buf
[0] == '/'))
1443 _dl_debug_printf_c (first
? "%s" : ":%s", buf
);
1451 _dl_debug_printf_c ("\t\t(%s from file %s)\n", what
,
1452 DSO_FILENAME (name
));
1454 _dl_debug_printf_c ("\t\t(%s)\n", what
);
1457 /* Open a file and verify it is an ELF file for this architecture. We
1458 ignore only ELF files for other architectures. Non-ELF files and
1459 ELF files with different header information cause fatal errors since
1460 this could mean there is something wrong in the installation and the
1461 user might want to know about this.
1463 If FD is not -1, then the file is already open and FD refers to it.
1464 In that case, FD is consumed for both successful and error returns. */
1466 open_verify (const char *name
, int fd
,
1467 struct filebuf
*fbp
, struct link_map
*loader
,
1468 int whatcode
, int mode
, bool *found_other_class
, bool free_name
)
1470 /* This is the expected ELF header. */
1471 #define ELF32_CLASS ELFCLASS32
1472 #define ELF64_CLASS ELFCLASS64
1473 #ifndef VALID_ELF_HEADER
1474 # define VALID_ELF_HEADER(hdr,exp,size) (memcmp (hdr, exp, size) == 0)
1475 # define VALID_ELF_OSABI(osabi) (osabi == ELFOSABI_SYSV)
1476 # define VALID_ELF_ABIVERSION(osabi,ver) (ver == 0)
1477 #elif defined MORE_ELF_HEADER_DATA
1478 MORE_ELF_HEADER_DATA
;
1480 static const unsigned char expected
[EI_NIDENT
] =
1482 [EI_MAG0
] = ELFMAG0
,
1483 [EI_MAG1
] = ELFMAG1
,
1484 [EI_MAG2
] = ELFMAG2
,
1485 [EI_MAG3
] = ELFMAG3
,
1486 [EI_CLASS
] = ELFW(CLASS
),
1487 [EI_DATA
] = byteorder
,
1488 [EI_VERSION
] = EV_CURRENT
,
1489 [EI_OSABI
] = ELFOSABI_SYSV
,
1494 ElfW(Word
) vendorlen
;
1498 } expected_note
= { 4, 16, 1, "GNU" };
1499 /* Initialize it to make the compiler happy. */
1500 const char *errstring
= NULL
;
1504 /* Give the auditing libraries a chance. */
1505 if (__glibc_unlikely (GLRO(dl_naudit
) > 0) && whatcode
!= 0
1506 && loader
->l_auditing
== 0)
1508 const char *original_name
= name
;
1509 struct audit_ifaces
*afct
= GLRO(dl_audit
);
1510 for (unsigned int cnt
= 0; cnt
< GLRO(dl_naudit
); ++cnt
)
1512 if (afct
->objsearch
!= NULL
)
1514 name
= afct
->objsearch (name
, &loader
->l_audit
[cnt
].cookie
,
1517 /* Ignore the path. */
1524 if (fd
!= -1 && name
!= original_name
&& strcmp (name
, original_name
))
1526 /* An audit library changed what we're supposed to open,
1527 so FD no longer matches it. */
1528 __close_nocancel (fd
);
1535 /* Open the file. We always open files read-only. */
1536 fd
= __open64_nocancel (name
, O_RDONLY
| O_CLOEXEC
);
1541 ElfW(Phdr
) *phdr
, *ph
;
1542 ElfW(Word
) *abi_note
;
1543 ElfW(Word
) *abi_note_malloced
= NULL
;
1544 unsigned int osversion
;
1547 /* We successfully opened the file. Now verify it is a file
1551 assert (sizeof (fbp
->buf
) > sizeof (ElfW(Ehdr
)));
1552 /* Read in the header. */
1555 ssize_t retlen
= __read_nocancel (fd
, fbp
->buf
+ fbp
->len
,
1556 sizeof (fbp
->buf
) - fbp
->len
);
1561 while (__glibc_unlikely (fbp
->len
< sizeof (ElfW(Ehdr
))));
1563 /* This is where the ELF header is loaded. */
1564 ehdr
= (ElfW(Ehdr
) *) fbp
->buf
;
1566 /* Now run the tests. */
1567 if (__glibc_unlikely (fbp
->len
< (ssize_t
) sizeof (ElfW(Ehdr
))))
1570 errstring
= (errval
== 0
1571 ? N_("file too short") : N_("cannot read file data"));
1575 char *realname
= (char *) name
;
1576 name
= strdupa (realname
);
1579 lose (errval
, fd
, name
, NULL
, NULL
, errstring
, NULL
, 0);
1582 /* See whether the ELF header is what we expect. */
1583 if (__glibc_unlikely (! VALID_ELF_HEADER (ehdr
->e_ident
, expected
,
1585 || !VALID_ELF_ABIVERSION (ehdr
->e_ident
[EI_OSABI
],
1586 ehdr
->e_ident
[EI_ABIVERSION
])
1587 || memcmp (&ehdr
->e_ident
[EI_PAD
],
1589 EI_NIDENT
- EI_PAD
) != 0))
1591 /* Something is wrong. */
1592 const Elf32_Word
*magp
= (const void *) ehdr
->e_ident
;
1594 #if BYTE_ORDER == LITTLE_ENDIAN
1595 ((ELFMAG0
<< (EI_MAG0
* 8))
1596 | (ELFMAG1
<< (EI_MAG1
* 8))
1597 | (ELFMAG2
<< (EI_MAG2
* 8))
1598 | (ELFMAG3
<< (EI_MAG3
* 8)))
1600 ((ELFMAG0
<< (EI_MAG3
* 8))
1601 | (ELFMAG1
<< (EI_MAG2
* 8))
1602 | (ELFMAG2
<< (EI_MAG1
* 8))
1603 | (ELFMAG3
<< (EI_MAG0
* 8)))
1606 errstring
= N_("invalid ELF header");
1607 else if (ehdr
->e_ident
[EI_CLASS
] != ELFW(CLASS
))
1609 /* This is not a fatal error. On architectures where
1610 32-bit and 64-bit binaries can be run this might
1612 *found_other_class
= true;
1615 else if (ehdr
->e_ident
[EI_DATA
] != byteorder
)
1617 if (BYTE_ORDER
== BIG_ENDIAN
)
1618 errstring
= N_("ELF file data encoding not big-endian");
1620 errstring
= N_("ELF file data encoding not little-endian");
1622 else if (ehdr
->e_ident
[EI_VERSION
] != EV_CURRENT
)
1624 = N_("ELF file version ident does not match current one");
1625 /* XXX We should be able so set system specific versions which are
1627 else if (!VALID_ELF_OSABI (ehdr
->e_ident
[EI_OSABI
]))
1628 errstring
= N_("ELF file OS ABI invalid");
1629 else if (!VALID_ELF_ABIVERSION (ehdr
->e_ident
[EI_OSABI
],
1630 ehdr
->e_ident
[EI_ABIVERSION
]))
1631 errstring
= N_("ELF file ABI version invalid");
1632 else if (memcmp (&ehdr
->e_ident
[EI_PAD
], &expected
[EI_PAD
],
1633 EI_NIDENT
- EI_PAD
) != 0)
1634 errstring
= N_("nonzero padding in e_ident");
1636 /* Otherwise we don't know what went wrong. */
1637 errstring
= N_("internal error");
1642 if (__glibc_unlikely (ehdr
->e_version
!= EV_CURRENT
))
1644 errstring
= N_("ELF file version does not match current one");
1647 if (! __glibc_likely (elf_machine_matches_host (ehdr
)))
1649 else if (__glibc_unlikely (ehdr
->e_type
!= ET_DYN
1650 && ehdr
->e_type
!= ET_EXEC
))
1652 errstring
= N_("only ET_DYN and ET_EXEC can be loaded");
1655 else if (__glibc_unlikely (ehdr
->e_phentsize
!= sizeof (ElfW(Phdr
))))
1657 errstring
= N_("ELF file's phentsize not the expected size");
1661 maplength
= ehdr
->e_phnum
* sizeof (ElfW(Phdr
));
1662 if (ehdr
->e_phoff
+ maplength
<= (size_t) fbp
->len
)
1663 phdr
= (void *) (fbp
->buf
+ ehdr
->e_phoff
);
1666 phdr
= alloca (maplength
);
1667 if ((size_t) __pread64_nocancel (fd
, (void *) phdr
, maplength
,
1668 ehdr
->e_phoff
) != maplength
)
1672 errstring
= N_("cannot read file data");
1677 if (__glibc_unlikely (elf_machine_reject_phdr_p
1678 (phdr
, ehdr
->e_phnum
, fbp
->buf
, fbp
->len
,
1682 /* Check .note.ABI-tag if present. */
1683 for (ph
= phdr
; ph
< &phdr
[ehdr
->e_phnum
]; ++ph
)
1684 if (ph
->p_type
== PT_NOTE
&& ph
->p_filesz
>= 32
1685 && (ph
->p_align
== 4 || ph
->p_align
== 8))
1687 ElfW(Addr
) size
= ph
->p_filesz
;
1689 if (ph
->p_offset
+ size
<= (size_t) fbp
->len
)
1690 abi_note
= (void *) (fbp
->buf
+ ph
->p_offset
);
1693 /* Note: __libc_use_alloca is not usable here, because
1694 thread info may not have been set up yet. */
1695 if (size
< __MAX_ALLOCA_CUTOFF
)
1696 abi_note
= alloca (size
);
1699 /* There could be multiple PT_NOTEs. */
1700 abi_note_malloced
= realloc (abi_note_malloced
, size
);
1701 if (abi_note_malloced
== NULL
)
1704 abi_note
= abi_note_malloced
;
1706 if (__pread64_nocancel (fd
, (void *) abi_note
, size
,
1707 ph
->p_offset
) != size
)
1709 free (abi_note_malloced
);
1714 while (memcmp (abi_note
, &expected_note
, sizeof (expected_note
)))
1716 ElfW(Addr
) note_size
1717 = ELF_NOTE_NEXT_OFFSET (abi_note
[0], abi_note
[1],
1720 if (size
- 32 < note_size
)
1726 abi_note
= (void *) abi_note
+ note_size
;
1732 osversion
= (abi_note
[5] & 0xff) * 65536
1733 + (abi_note
[6] & 0xff) * 256
1734 + (abi_note
[7] & 0xff);
1735 if (abi_note
[4] != __ABI_TAG_OS
1736 || (GLRO(dl_osversion
) && GLRO(dl_osversion
) < osversion
))
1739 __close_nocancel (fd
);
1740 __set_errno (ENOENT
);
1746 free (abi_note_malloced
);
1752 /* Try to open NAME in one of the directories in *DIRSP.
1753 Return the fd, or -1. If successful, fill in *REALNAME
1754 with the malloc'd full directory name. If it turns out
1755 that none of the directories in *DIRSP exists, *DIRSP is
1756 replaced with (void *) -1, and the old value is free()d
1757 if MAY_FREE_DIRS is true. */
1760 open_path (const char *name
, size_t namelen
, int mode
,
1761 struct r_search_path_struct
*sps
, char **realname
,
1762 struct filebuf
*fbp
, struct link_map
*loader
, int whatcode
,
1763 bool *found_other_class
)
1765 struct r_search_path_elem
**dirs
= sps
->dirs
;
1768 const char *current_what
= NULL
;
1771 if (__glibc_unlikely (dirs
== NULL
))
1772 /* We're called before _dl_init_paths when loading the main executable
1773 given on the command line when rtld is run directly. */
1776 buf
= alloca (max_dirnamelen
+ max_capstrlen
+ namelen
);
1779 struct r_search_path_elem
*this_dir
= *dirs
;
1786 /* If we are debugging the search for libraries print the path
1787 now if it hasn't happened now. */
1788 if (__glibc_unlikely (GLRO(dl_debug_mask
) & DL_DEBUG_LIBS
)
1789 && current_what
!= this_dir
->what
)
1791 current_what
= this_dir
->what
;
1792 print_search_path (dirs
, current_what
, this_dir
->where
);
1795 edp
= (char *) __mempcpy (buf
, this_dir
->dirname
, this_dir
->dirnamelen
);
1796 for (cnt
= 0; fd
== -1 && cnt
< ncapstr
; ++cnt
)
1798 /* Skip this directory if we know it does not exist. */
1799 if (this_dir
->status
[cnt
] == nonexisting
)
1803 ((char *) __mempcpy (__mempcpy (edp
, capstr
[cnt
].str
,
1808 /* Print name we try if this is wanted. */
1809 if (__glibc_unlikely (GLRO(dl_debug_mask
) & DL_DEBUG_LIBS
))
1810 _dl_debug_printf (" trying file=%s\n", buf
);
1812 fd
= open_verify (buf
, -1, fbp
, loader
, whatcode
, mode
,
1813 found_other_class
, false);
1814 if (this_dir
->status
[cnt
] == unknown
)
1817 this_dir
->status
[cnt
] = existing
;
1818 /* Do not update the directory information when loading
1819 auditing code. We must try to disturb the program as
1820 little as possible. */
1821 else if (loader
== NULL
1822 || GL(dl_ns
)[loader
->l_ns
]._ns_loaded
->l_auditing
== 0)
1824 /* We failed to open machine dependent library. Let's
1825 test whether there is any directory at all. */
1828 buf
[buflen
- namelen
- 1] = '\0';
1830 if (__xstat64 (_STAT_VER
, buf
, &st
) != 0
1831 || ! S_ISDIR (st
.st_mode
))
1832 /* The directory does not exist or it is no directory. */
1833 this_dir
->status
[cnt
] = nonexisting
;
1835 this_dir
->status
[cnt
] = existing
;
1839 /* Remember whether we found any existing directory. */
1840 here_any
|= this_dir
->status
[cnt
] != nonexisting
;
1842 if (fd
!= -1 && __glibc_unlikely (mode
& __RTLD_SECURE
)
1843 && __libc_enable_secure
)
1845 /* This is an extra security effort to make sure nobody can
1846 preload broken shared objects which are in the trusted
1847 directories and so exploit the bugs. */
1850 if (__fxstat64 (_STAT_VER
, fd
, &st
) != 0
1851 || (st
.st_mode
& S_ISUID
) == 0)
1853 /* The shared object cannot be tested for being SUID
1854 or this bit is not set. In this case we must not
1856 __close_nocancel (fd
);
1858 /* We simply ignore the file, signal this by setting
1859 the error value which would have been set by `open'. */
1867 *realname
= (char *) malloc (buflen
);
1868 if (*realname
!= NULL
)
1870 memcpy (*realname
, buf
, buflen
);
1875 /* No memory for the name, we certainly won't be able
1876 to load and link it. */
1877 __close_nocancel (fd
);
1881 if (here_any
&& (err
= errno
) != ENOENT
&& err
!= EACCES
)
1882 /* The file exists and is readable, but something went wrong. */
1885 /* Remember whether we found anything. */
1888 while (*++dirs
!= NULL
);
1890 /* Remove the whole path if none of the directories exists. */
1891 if (__glibc_unlikely (! any
))
1893 /* Paths which were allocated using the minimal malloc() in ld.so
1894 must not be freed using the general free() in libc. */
1898 /* rtld_search_dirs and env_path_list are attribute_relro, therefore
1899 avoid writing into it. */
1900 if (sps
!= &rtld_search_dirs
&& sps
!= &env_path_list
)
1901 sps
->dirs
= (void *) -1;
1907 /* Map in the shared object file NAME. */
1910 _dl_map_object (struct link_map
*loader
, const char *name
,
1911 int type
, int trace_mode
, int mode
, Lmid_t nsid
)
1914 const char *origname
= NULL
;
1921 assert (nsid
< GL(dl_nns
));
1923 /* Look for this name among those already loaded. */
1924 for (l
= GL(dl_ns
)[nsid
]._ns_loaded
; l
; l
= l
->l_next
)
1926 /* If the requested name matches the soname of a loaded object,
1927 use that object. Elide this check for names that have not
1929 if (__glibc_unlikely ((l
->l_faked
| l
->l_removed
) != 0))
1931 if (!_dl_name_match_p (name
, l
))
1935 if (__glibc_likely (l
->l_soname_added
)
1936 || l
->l_info
[DT_SONAME
] == NULL
)
1939 soname
= ((const char *) D_PTR (l
, l_info
[DT_STRTAB
])
1940 + l
->l_info
[DT_SONAME
]->d_un
.d_val
);
1941 if (strcmp (name
, soname
) != 0)
1944 /* We have a match on a new name -- cache it. */
1945 add_name_to_object (l
, soname
);
1946 l
->l_soname_added
= 1;
1949 /* We have a match. */
1953 /* Display information if we are debugging. */
1954 if (__glibc_unlikely (GLRO(dl_debug_mask
) & DL_DEBUG_FILES
)
1956 _dl_debug_printf ((mode
& __RTLD_CALLMAP
) == 0
1957 ? "\nfile=%s [%lu]; needed by %s [%lu]\n"
1958 : "\nfile=%s [%lu]; dynamically loaded by %s [%lu]\n",
1959 name
, nsid
, DSO_FILENAME (loader
->l_name
), loader
->l_ns
);
1962 /* Give the auditing libraries a chance to change the name before we
1964 if (__glibc_unlikely (GLRO(dl_naudit
) > 0)
1965 && (loader
== NULL
|| loader
->l_auditing
== 0))
1967 struct audit_ifaces
*afct
= GLRO(dl_audit
);
1968 for (unsigned int cnt
= 0; cnt
< GLRO(dl_naudit
); ++cnt
)
1970 if (afct
->objsearch
!= NULL
)
1972 const char *before
= name
;
1973 name
= afct
->objsearch (name
, &loader
->l_audit
[cnt
].cookie
,
1977 /* Do not try anything further. */
1981 if (before
!= name
&& strcmp (before
, name
) != 0)
1983 if (__glibc_unlikely (GLRO(dl_debug_mask
) & DL_DEBUG_FILES
))
1984 _dl_debug_printf ("audit changed filename %s -> %s\n",
1987 if (origname
== NULL
)
1997 /* Will be true if we found a DSO which is of the other ELF class. */
1998 bool found_other_class
= false;
2000 if (strchr (name
, '/') == NULL
)
2002 /* Search for NAME in several places. */
2004 size_t namelen
= strlen (name
) + 1;
2006 if (__glibc_unlikely (GLRO(dl_debug_mask
) & DL_DEBUG_LIBS
))
2007 _dl_debug_printf ("find library=%s [%lu]; searching\n", name
, nsid
);
2011 /* When the object has the RUNPATH information we don't use any
2013 if (loader
== NULL
|| loader
->l_info
[DT_RUNPATH
] == NULL
)
2015 /* This is the executable's map (if there is one). Make sure that
2016 we do not look at it twice. */
2017 struct link_map
*main_map
= GL(dl_ns
)[LM_ID_BASE
]._ns_loaded
;
2018 bool did_main_map
= false;
2020 /* First try the DT_RPATH of the dependent object that caused NAME
2021 to be loaded. Then that object's dependent, and on up. */
2022 for (l
= loader
; l
; l
= l
->l_loader
)
2023 if (cache_rpath (l
, &l
->l_rpath_dirs
, DT_RPATH
, "RPATH"))
2025 fd
= open_path (name
, namelen
, mode
,
2027 &realname
, &fb
, loader
, LA_SER_RUNPATH
,
2028 &found_other_class
);
2032 did_main_map
|= l
== main_map
;
2035 /* If dynamically linked, try the DT_RPATH of the executable
2036 itself. NB: we do this for lookups in any namespace. */
2037 if (fd
== -1 && !did_main_map
2038 && main_map
!= NULL
&& main_map
->l_type
!= lt_loaded
2039 && cache_rpath (main_map
, &main_map
->l_rpath_dirs
, DT_RPATH
,
2041 fd
= open_path (name
, namelen
, mode
,
2042 &main_map
->l_rpath_dirs
,
2043 &realname
, &fb
, loader
?: main_map
, LA_SER_RUNPATH
,
2044 &found_other_class
);
2047 /* Try the LD_LIBRARY_PATH environment variable. */
2048 if (fd
== -1 && env_path_list
.dirs
!= (void *) -1)
2049 fd
= open_path (name
, namelen
, mode
, &env_path_list
,
2051 loader
?: GL(dl_ns
)[LM_ID_BASE
]._ns_loaded
,
2052 LA_SER_LIBPATH
, &found_other_class
);
2054 /* Look at the RUNPATH information for this binary. */
2055 if (fd
== -1 && loader
!= NULL
2056 && cache_rpath (loader
, &loader
->l_runpath_dirs
,
2057 DT_RUNPATH
, "RUNPATH"))
2058 fd
= open_path (name
, namelen
, mode
,
2059 &loader
->l_runpath_dirs
, &realname
, &fb
, loader
,
2060 LA_SER_RUNPATH
, &found_other_class
);
2064 realname
= _dl_sysdep_open_object (name
, namelen
, &fd
);
2065 if (realname
!= NULL
)
2067 fd
= open_verify (realname
, fd
,
2068 &fb
, loader
?: GL(dl_ns
)[nsid
]._ns_loaded
,
2069 LA_SER_CONFIG
, mode
, &found_other_class
,
2078 && (__glibc_likely ((mode
& __RTLD_SECURE
) == 0)
2079 || ! __libc_enable_secure
)
2080 && __glibc_likely (GLRO(dl_inhibit_cache
) == 0))
2082 /* Check the list of libraries in the file /etc/ld.so.cache,
2083 for compatibility with Linux's ldconfig program. */
2084 char *cached
= _dl_load_cache_lookup (name
);
2088 // XXX Correct to unconditionally default to namespace 0?
2090 ?: GL(dl_ns
)[LM_ID_BASE
]._ns_loaded
2096 /* If the loader has the DF_1_NODEFLIB flag set we must not
2097 use a cache entry from any of these directories. */
2098 if (__glibc_unlikely (l
->l_flags_1
& DF_1_NODEFLIB
))
2100 const char *dirp
= system_dirs
;
2101 unsigned int cnt
= 0;
2105 if (memcmp (cached
, dirp
, system_dirs_len
[cnt
]) == 0)
2107 /* The prefix matches. Don't use the entry. */
2113 dirp
+= system_dirs_len
[cnt
] + 1;
2116 while (cnt
< nsystem_dirs_len
);
2121 fd
= open_verify (cached
, -1,
2122 &fb
, loader
?: GL(dl_ns
)[nsid
]._ns_loaded
,
2123 LA_SER_CONFIG
, mode
, &found_other_class
,
2125 if (__glibc_likely (fd
!= -1))
2134 /* Finally, try the default path. */
2136 && ((l
= loader
?: GL(dl_ns
)[nsid
]._ns_loaded
) == NULL
2137 || __glibc_likely (!(l
->l_flags_1
& DF_1_NODEFLIB
)))
2138 && rtld_search_dirs
.dirs
!= (void *) -1)
2139 fd
= open_path (name
, namelen
, mode
, &rtld_search_dirs
,
2140 &realname
, &fb
, l
, LA_SER_DEFAULT
, &found_other_class
);
2142 /* Add another newline when we are tracing the library loading. */
2143 if (__glibc_unlikely (GLRO(dl_debug_mask
) & DL_DEBUG_LIBS
))
2144 _dl_debug_printf ("\n");
2148 /* The path may contain dynamic string tokens. */
2150 ? expand_dynamic_string_token (loader
, name
)
2152 if (realname
== NULL
)
2156 fd
= open_verify (realname
, -1, &fb
,
2157 loader
?: GL(dl_ns
)[nsid
]._ns_loaded
, 0, mode
,
2158 &found_other_class
, true);
2159 if (__glibc_unlikely (fd
== -1))
2167 /* In case the LOADER information has only been provided to get to
2168 the appropriate RUNPATH/RPATH information we do not need it
2170 if (mode
& __RTLD_CALLMAP
)
2173 if (__glibc_unlikely (fd
== -1))
2176 && __glibc_likely ((GLRO(dl_debug_mask
) & DL_DEBUG_PRELINK
) == 0))
2178 /* We haven't found an appropriate library. But since we
2179 are only interested in the list of libraries this isn't
2180 so severe. Fake an entry with all the information we
2182 static const Elf_Symndx dummy_bucket
= STN_UNDEF
;
2184 /* Allocate a new object map. */
2185 if ((name_copy
= __strdup (name
)) == NULL
2186 || (l
= _dl_new_object (name_copy
, name
, type
, loader
,
2187 mode
, nsid
)) == NULL
)
2190 _dl_signal_error (ENOMEM
, name
, NULL
,
2191 N_("cannot create shared object descriptor"));
2193 /* Signal that this is a faked entry. */
2195 /* Since the descriptor is initialized with zero we do not
2197 l->l_reserved = 0; */
2198 l
->l_buckets
= &dummy_bucket
;
2202 /* Enter the object in the object list. */
2203 _dl_add_to_namespace_list (l
, nsid
);
2207 else if (found_other_class
)
2208 _dl_signal_error (0, name
, NULL
,
2209 ELFW(CLASS
) == ELFCLASS32
2210 ? N_("wrong ELF class: ELFCLASS64")
2211 : N_("wrong ELF class: ELFCLASS32"));
2213 _dl_signal_error (errno
, name
, NULL
,
2214 N_("cannot open shared object file"));
2217 void *stack_end
= __libc_stack_end
;
2218 return _dl_map_object_from_fd (name
, origname
, fd
, &fb
, realname
, loader
,
2219 type
, mode
, &stack_end
, nsid
);
2222 struct add_path_state
2231 add_path (struct add_path_state
*p
, const struct r_search_path_struct
*sps
,
2234 if (sps
->dirs
!= (void *) -1)
2236 struct r_search_path_elem
**dirs
= sps
->dirs
;
2239 const struct r_search_path_elem
*const r
= *dirs
++;
2243 p
->si
->dls_size
+= MAX (2, r
->dirnamelen
);
2247 Dl_serpath
*const sp
= &p
->si
->dls_serpath
[p
->idx
++];
2248 sp
->dls_name
= p
->allocptr
;
2249 if (r
->dirnamelen
< 2)
2250 *p
->allocptr
++ = r
->dirnamelen
? '/' : '.';
2252 p
->allocptr
= __mempcpy (p
->allocptr
,
2253 r
->dirname
, r
->dirnamelen
- 1);
2254 *p
->allocptr
++ = '\0';
2255 sp
->dls_flags
= flags
;
2258 while (*dirs
!= NULL
);
2263 _dl_rtld_di_serinfo (struct link_map
*loader
, Dl_serinfo
*si
, bool counting
)
2271 struct add_path_state p
=
2273 .counting
= counting
,
2276 .allocptr
= (char *) &si
->dls_serpath
[si
->dls_cnt
]
2279 # define add_path(p, sps, flags) add_path(p, sps, 0) /* XXX */
2281 /* When the object has the RUNPATH information we don't use any RPATHs. */
2282 if (loader
->l_info
[DT_RUNPATH
] == NULL
)
2284 /* First try the DT_RPATH of the dependent object that caused NAME
2285 to be loaded. Then that object's dependent, and on up. */
2287 struct link_map
*l
= loader
;
2290 if (cache_rpath (l
, &l
->l_rpath_dirs
, DT_RPATH
, "RPATH"))
2291 add_path (&p
, &l
->l_rpath_dirs
, XXX_RPATH
);
2296 /* If dynamically linked, try the DT_RPATH of the executable itself. */
2297 if (loader
->l_ns
== LM_ID_BASE
)
2299 l
= GL(dl_ns
)[LM_ID_BASE
]._ns_loaded
;
2300 if (l
!= NULL
&& l
->l_type
!= lt_loaded
&& l
!= loader
)
2301 if (cache_rpath (l
, &l
->l_rpath_dirs
, DT_RPATH
, "RPATH"))
2302 add_path (&p
, &l
->l_rpath_dirs
, XXX_RPATH
);
2306 /* Try the LD_LIBRARY_PATH environment variable. */
2307 add_path (&p
, &env_path_list
, XXX_ENV
);
2309 /* Look at the RUNPATH information for this binary. */
2310 if (cache_rpath (loader
, &loader
->l_runpath_dirs
, DT_RUNPATH
, "RUNPATH"))
2311 add_path (&p
, &loader
->l_runpath_dirs
, XXX_RUNPATH
);
2314 Here is where ld.so.cache gets checked, but we don't have
2315 a way to indicate that in the results for Dl_serinfo. */
2317 /* Finally, try the default path. */
2318 if (!(loader
->l_flags_1
& DF_1_NODEFLIB
))
2319 add_path (&p
, &rtld_search_dirs
, XXX_default
);
2322 /* Count the struct size before the string area, which we didn't
2323 know before we completed dls_cnt. */
2324 si
->dls_size
+= (char *) &si
->dls_serpath
[si
->dls_cnt
] - (char *) si
;