/* Map in a shared object's segments from the file. Copyright (C) 1995-2020 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. The GNU C Library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with the GNU C Library; if not, see . */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* Type for the buffer we put the ELF header and hopefully the program header. This buffer does not really have to be too large. In most cases the program header follows the ELF header directly. If this is not the case all bets are off and we can make the header arbitrarily large and still won't get it read. This means the only question is how large are the ELF and program header combined. The ELF header 32-bit files is 52 bytes long and in 64-bit files is 64 bytes long. Each program header entry is again 32 and 56 bytes long respectively. I.e., even with a file which has 10 program header entries we only have to read 372B/624B respectively. Add to this a bit of margin for program notes and reading 512B and 832B for 32-bit and 64-bit files respecitvely is enough. If this heuristic should really fail for some file the code in `_dl_map_object_from_fd' knows how to recover. */ struct filebuf { ssize_t len; #if __WORDSIZE == 32 # define FILEBUF_SIZE 512 #else # define FILEBUF_SIZE 832 #endif char buf[FILEBUF_SIZE] __attribute__ ((aligned (__alignof (ElfW(Ehdr))))); }; #include "dynamic-link.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #if BYTE_ORDER == BIG_ENDIAN # define byteorder ELFDATA2MSB #elif BYTE_ORDER == LITTLE_ENDIAN # define byteorder ELFDATA2LSB #else # error "Unknown BYTE_ORDER " BYTE_ORDER # define byteorder ELFDATANONE #endif #define STRING(x) __STRING (x) int __stack_prot attribute_hidden attribute_relro #if _STACK_GROWS_DOWN && defined PROT_GROWSDOWN = PROT_GROWSDOWN; #elif _STACK_GROWS_UP && defined PROT_GROWSUP = PROT_GROWSUP; #else = 0; #endif /* This is the decomposed LD_LIBRARY_PATH search path. */ struct r_search_path_struct __rtld_env_path_list attribute_relro; /* List of the hardware capabilities we might end up using. */ #ifdef SHARED static const struct r_strlenpair *capstr attribute_relro; static size_t ncapstr attribute_relro; static size_t max_capstrlen attribute_relro; #else enum { ncapstr = 1, max_capstrlen = 0 }; #endif /* Get the generated information about the trusted directories. Use an array of concatenated strings to avoid relocations. See gen-trusted-dirs.awk. */ #include "trusted-dirs.h" static const char system_dirs[] = SYSTEM_DIRS; static const size_t system_dirs_len[] = { SYSTEM_DIRS_LEN }; #define nsystem_dirs_len array_length (system_dirs_len) static bool is_trusted_path_normalize (const char *path, size_t len) { if (len == 0) return false; char *npath = (char *) alloca (len + 2); char *wnp = npath; while (*path != '\0') { if (path[0] == '/') { if (path[1] == '.') { if (path[2] == '.' && (path[3] == '/' || path[3] == '\0')) { while (wnp > npath && *--wnp != '/') ; path += 3; continue; } else if (path[2] == '/' || path[2] == '\0') { path += 2; continue; } } if (wnp > npath && wnp[-1] == '/') { ++path; continue; } } *wnp++ = *path++; } if (wnp == npath || wnp[-1] != '/') *wnp++ = '/'; const char *trun = system_dirs; for (size_t idx = 0; idx < nsystem_dirs_len; ++idx) { if (wnp - npath >= system_dirs_len[idx] && memcmp (trun, npath, system_dirs_len[idx]) == 0) /* Found it. */ return true; trun += system_dirs_len[idx] + 1; } return false; } /* Given a substring starting at INPUT, just after the DST '$' start token, determine if INPUT contains DST token REF, following the ELF gABI rules for DSTs: * Longest possible sequence using the rules (greedy). * Must start with a $ (enforced by caller). * Must follow $ with one underscore or ASCII [A-Za-z] (caller follows these rules for REF) or '{' (start curly quoted name). * Must follow first two characters with zero or more [A-Za-z0-9_] (enforced by caller) or '}' (end curly quoted name). If the sequence is a DST matching REF then the length of the DST (excluding the $ sign but including curly braces, if any) is returned, otherwise 0. */ static size_t is_dst (const char *input, const char *ref) { bool is_curly = false; /* Is a ${...} input sequence? */ if (input[0] == '{') { is_curly = true; ++input; } /* Check for matching name, following closing curly brace (if required), or trailing characters which are part of an identifier. */ size_t rlen = strlen (ref); if (strncmp (input, ref, rlen) != 0 || (is_curly && input[rlen] != '}') || ((input[rlen] >= 'A' && input[rlen] <= 'Z') || (input[rlen] >= 'a' && input[rlen] <= 'z') || (input[rlen] >= '0' && input[rlen] <= '9') || (input[rlen] == '_'))) return 0; if (is_curly) /* Count the two curly braces. */ return rlen + 2; else return rlen; } /* INPUT should be the start of a path e.g DT_RPATH or name e.g. DT_NEEDED. The return value is the number of known DSTs found. We count all known DSTs regardless of __libc_enable_secure; the caller is responsible for enforcing the security of the substitution rules (usually _dl_dst_substitute). */ size_t _dl_dst_count (const char *input) { size_t cnt = 0; input = strchr (input, '$'); /* Most likely there is no DST. */ if (__glibc_likely (input == NULL)) return 0; do { size_t len; ++input; /* All DSTs must follow ELF gABI rules, see is_dst (). */ if ((len = is_dst (input, "ORIGIN")) != 0 || (len = is_dst (input, "PLATFORM")) != 0 || (len = is_dst (input, "LIB")) != 0) ++cnt; /* There may be more than one DST in the input. */ input = strchr (input + len, '$'); } while (input != NULL); return cnt; } /* Process INPUT for DSTs and store in RESULT using the information from link map L to resolve the DSTs. This function only handles one path at a time and does not handle colon-separated path lists (see fillin_rpath ()). Lastly the size of result in bytes should be at least equal to the value returned by DL_DST_REQUIRED. Note that it is possible for a DT_NEEDED, DT_AUXILIARY, and DT_FILTER entries to have colons, but we treat those as literal colons here, not as path list delimeters. */ char * _dl_dst_substitute (struct link_map *l, const char *input, char *result) { /* Copy character-by-character from input into the working pointer looking for any DSTs. We track the start of input and if we are going to check for trusted paths, all of which are part of $ORIGIN handling in SUID/SGID cases (see below). In some cases, like when a DST cannot be replaced, we may set result to an empty string and return. */ char *wp = result; const char *start = input; bool check_for_trusted = false; do { if (__glibc_unlikely (*input == '$')) { const char *repl = NULL; size_t len; ++input; if ((len = is_dst (input, "ORIGIN")) != 0) { /* For SUID/GUID programs we normally ignore the path with $ORIGIN in DT_RUNPATH, or DT_RPATH. However, there is one exception to this rule, and it is: * $ORIGIN appears as the first path element, and is the only string in the path or is immediately followed by a path separator and the rest of the path, and ... * The path is rooted in a trusted directory. This exception allows such programs to reference shared libraries in subdirectories of trusted directories. The use case is one of general organization and deployment flexibility. Trusted directories are usually such paths as "/lib64" or "/usr/lib64", and the usual RPATHs take the form of [$ORIGIN/../$LIB/somedir]. */ if (__glibc_unlikely (__libc_enable_secure) && !(input == start + 1 && (input[len] == '\0' || input[len] == '/'))) repl = (const char *) -1; else repl = l->l_origin; check_for_trusted = (__libc_enable_secure && l->l_type == lt_executable); } else if ((len = is_dst (input, "PLATFORM")) != 0) repl = GLRO(dl_platform); else if ((len = is_dst (input, "LIB")) != 0) repl = DL_DST_LIB; if (repl != NULL && repl != (const char *) -1) { wp = __stpcpy (wp, repl); input += len; } else if (len != 0) { /* We found a valid DST that we know about, but we could not find a replacement value for it, therefore we cannot use this path and discard it. */ *result = '\0'; return result; } else /* No DST we recognize. */ *wp++ = '$'; } else { *wp++ = *input++; } } while (*input != '\0'); /* In SUID/SGID programs, after $ORIGIN expansion the normalized path must be rooted in one of the trusted directories. The $LIB and $PLATFORM DST cannot in any way be manipulated by the caller because they are fixed values that are set by the dynamic loader and therefore any paths using just $LIB or $PLATFORM need not be checked for trust, the authors of the binaries themselves are trusted to have designed this correctly. Only $ORIGIN is tested in this way because it may be manipulated in some ways with hard links. */ if (__glibc_unlikely (check_for_trusted) && !is_trusted_path_normalize (result, wp - result)) { *result = '\0'; return result; } *wp = '\0'; return result; } /* Return a malloc allocated copy of INPUT with all recognized DSTs replaced. On some platforms it might not be possible to determine the path from which the object belonging to the map is loaded. In this case the path containing the DST is left out. On error NULL is returned. */ static char * expand_dynamic_string_token (struct link_map *l, const char *input) { /* We make two runs over the string. First we determine how large the resulting string is and then we copy it over. Since this is no frequently executed operation we are looking here not for performance but rather for code size. */ size_t cnt; size_t total; char *result; /* Determine the number of DSTs. */ cnt = _dl_dst_count (input); /* If we do not have to replace anything simply copy the string. */ if (__glibc_likely (cnt == 0)) return __strdup (input); /* Determine the length of the substituted string. */ total = DL_DST_REQUIRED (l, input, strlen (input), cnt); /* Allocate the necessary memory. */ result = (char *) malloc (total + 1); if (result == NULL) return NULL; return _dl_dst_substitute (l, input, result); } /* Add `name' to the list of names for a particular shared object. `name' is expected to have been allocated with malloc and will be freed if the shared object already has this name. Returns false if the object already had this name. */ static void add_name_to_object (struct link_map *l, const char *name) { struct libname_list *lnp, *lastp; struct libname_list *newname; size_t name_len; lastp = NULL; for (lnp = l->l_libname; lnp != NULL; lastp = lnp, lnp = lnp->next) if (strcmp (name, lnp->name) == 0) return; name_len = strlen (name) + 1; newname = (struct libname_list *) malloc (sizeof *newname + name_len); if (newname == NULL) { /* No more memory. */ _dl_signal_error (ENOMEM, name, NULL, N_("cannot allocate name record")); return; } /* The object should have a libname set from _dl_new_object. */ assert (lastp != NULL); newname->name = memcpy (newname + 1, name, name_len); newname->next = NULL; newname->dont_free = 0; lastp->next = newname; } /* Standard search directories. */ struct r_search_path_struct __rtld_search_dirs attribute_relro; static size_t max_dirnamelen; 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) { char *cp; size_t nelems = 0; while ((cp = __strsep (&rpath, sep)) != NULL) { struct r_search_path_elem *dirp; char *to_free = NULL; size_t len = 0; /* `strsep' can pass an empty string. */ if (*cp != '\0') { to_free = cp = expand_dynamic_string_token (l, cp); /* expand_dynamic_string_token can return NULL in case of empty path or memory allocation failure. */ if (cp == NULL) continue; /* Compute the length after dynamic string token expansion and ignore empty paths. */ len = strlen (cp); if (len == 0) { free (to_free); continue; } /* Remove trailing slashes (except for "/"). */ while (len > 1 && cp[len - 1] == '/') --len; /* Now add one if there is none so far. */ if (len > 0 && cp[len - 1] != '/') cp[len++] = '/'; } /* See if this directory is already known. */ for (dirp = GL(dl_all_dirs); dirp != NULL; dirp = dirp->next) if (dirp->dirnamelen == len && memcmp (cp, dirp->dirname, len) == 0) break; if (dirp != NULL) { /* It is available, see whether it's on our own list. */ size_t cnt; for (cnt = 0; cnt < nelems; ++cnt) if (result[cnt] == dirp) break; if (cnt == nelems) result[nelems++] = dirp; } else { size_t cnt; enum r_dir_status init_val; size_t where_len = where ? strlen (where) + 1 : 0; /* It's a new directory. Create an entry and add it. */ dirp = (struct r_search_path_elem *) malloc (sizeof (*dirp) + ncapstr * sizeof (enum r_dir_status) + where_len + len + 1); if (dirp == NULL) _dl_signal_error (ENOMEM, NULL, NULL, N_("cannot create cache for search path")); dirp->dirname = ((char *) dirp + sizeof (*dirp) + ncapstr * sizeof (enum r_dir_status)); *((char *) __mempcpy ((char *) dirp->dirname, cp, len)) = '\0'; dirp->dirnamelen = len; if (len > max_dirnamelen) max_dirnamelen = len; /* We have to make sure all the relative directories are never ignored. The current directory might change and all our saved information would be void. */ init_val = cp[0] != '/' ? existing : unknown; for (cnt = 0; cnt < ncapstr; ++cnt) dirp->status[cnt] = init_val; dirp->what = what; if (__glibc_likely (where != NULL)) dirp->where = memcpy ((char *) dirp + sizeof (*dirp) + len + 1 + (ncapstr * sizeof (enum r_dir_status)), where, where_len); else dirp->where = NULL; dirp->next = GL(dl_all_dirs); GL(dl_all_dirs) = dirp; /* Put it in the result array. */ result[nelems++] = dirp; } free (to_free); } /* Terminate the array. */ result[nelems] = NULL; return result; } static bool decompose_rpath (struct r_search_path_struct *sps, const char *rpath, struct link_map *l, const char *what) { /* Make a copy we can work with. */ const char *where = l->l_name; char *cp; struct r_search_path_elem **result; size_t nelems; /* Initialize to please the compiler. */ const char *errstring = NULL; /* First see whether we must forget the RUNPATH and RPATH from this object. */ if (__glibc_unlikely (GLRO(dl_inhibit_rpath) != NULL) && !__libc_enable_secure) { const char *inhp = GLRO(dl_inhibit_rpath); do { const char *wp = where; while (*inhp == *wp && *wp != '\0') { ++inhp; ++wp; } if (*wp == '\0' && (*inhp == '\0' || *inhp == ':')) { /* This object is on the list of objects for which the RUNPATH and RPATH must not be used. */ sps->dirs = (void *) -1; return false; } while (*inhp != '\0') if (*inhp++ == ':') break; } while (*inhp != '\0'); } /* Ignore empty rpaths. */ if (*rpath == '\0') { sps->dirs = (struct r_search_path_elem **) -1; return false; } /* Make a writable copy. */ char *copy = __strdup (rpath); if (copy == NULL) { errstring = N_("cannot create RUNPATH/RPATH copy"); goto signal_error; } /* Count the number of necessary elements in the result array. */ nelems = 0; for (cp = copy; *cp != '\0'; ++cp) if (*cp == ':') ++nelems; /* Allocate room for the result. NELEMS + 1 is an upper limit for the number of necessary entries. */ result = (struct r_search_path_elem **) malloc ((nelems + 1 + 1) * sizeof (*result)); if (result == NULL) { free (copy); errstring = N_("cannot create cache for search path"); signal_error: _dl_signal_error (ENOMEM, NULL, NULL, errstring); } fillin_rpath (copy, result, ":", what, where, l); /* Free the copied RPATH string. `fillin_rpath' make own copies if necessary. */ free (copy); /* There is no path after expansion. */ if (result[0] == NULL) { free (result); sps->dirs = (struct r_search_path_elem **) -1; return false; } sps->dirs = result; /* The caller will change this value if we haven't used a real malloc. */ sps->malloced = 1; return true; } /* Make sure cached path information is stored in *SP and return true if there are any paths to search there. */ static bool cache_rpath (struct link_map *l, struct r_search_path_struct *sp, int tag, const char *what) { if (sp->dirs == (void *) -1) return false; if (sp->dirs != NULL) return true; if (l->l_info[tag] == NULL) { /* There is no path. */ sp->dirs = (void *) -1; return false; } /* Make sure the cache information is available. */ return decompose_rpath (sp, (const char *) (D_PTR (l, l_info[DT_STRTAB]) + l->l_info[tag]->d_un.d_val), l, what); } void _dl_init_paths (const char *llp, const char *source, const char *glibc_hwcaps_prepend, const char *glibc_hwcaps_mask) { size_t idx; const char *strp; struct r_search_path_elem *pelem, **aelem; size_t round_size; struct link_map __attribute__ ((unused)) *l = NULL; /* Initialize to please the compiler. */ const char *errstring = NULL; /* Fill in the information about the application's RPATH and the directories addressed by the LD_LIBRARY_PATH environment variable. */ #ifdef SHARED /* Get the capabilities. */ capstr = _dl_important_hwcaps (glibc_hwcaps_prepend, glibc_hwcaps_mask, &ncapstr, &max_capstrlen); #endif /* First set up the rest of the default search directory entries. */ aelem = __rtld_search_dirs.dirs = (struct r_search_path_elem **) malloc ((nsystem_dirs_len + 1) * sizeof (struct r_search_path_elem *)); if (__rtld_search_dirs.dirs == NULL) { errstring = N_("cannot create search path array"); signal_error: _dl_signal_error (ENOMEM, NULL, NULL, errstring); } round_size = ((2 * sizeof (struct r_search_path_elem) - 1 + ncapstr * sizeof (enum r_dir_status)) / sizeof (struct r_search_path_elem)); __rtld_search_dirs.dirs[0] = malloc (nsystem_dirs_len * round_size * sizeof (*__rtld_search_dirs.dirs[0])); if (__rtld_search_dirs.dirs[0] == NULL) { errstring = N_("cannot create cache for search path"); goto signal_error; } __rtld_search_dirs.malloced = 0; pelem = GL(dl_all_dirs) = __rtld_search_dirs.dirs[0]; strp = system_dirs; idx = 0; do { size_t cnt; *aelem++ = pelem; pelem->what = "system search path"; pelem->where = NULL; pelem->dirname = strp; pelem->dirnamelen = system_dirs_len[idx]; strp += system_dirs_len[idx] + 1; /* System paths must be absolute. */ assert (pelem->dirname[0] == '/'); for (cnt = 0; cnt < ncapstr; ++cnt) pelem->status[cnt] = unknown; pelem->next = (++idx == nsystem_dirs_len ? NULL : (pelem + round_size)); pelem += round_size; } while (idx < nsystem_dirs_len); max_dirnamelen = SYSTEM_DIRS_MAX_LEN; *aelem = NULL; #ifdef SHARED /* This points to the map of the main object. */ l = GL(dl_ns)[LM_ID_BASE]._ns_loaded; if (l != NULL) { assert (l->l_type != lt_loaded); if (l->l_info[DT_RUNPATH]) { /* Allocate room for the search path and fill in information from RUNPATH. */ decompose_rpath (&l->l_runpath_dirs, (const void *) (D_PTR (l, l_info[DT_STRTAB]) + l->l_info[DT_RUNPATH]->d_un.d_val), l, "RUNPATH"); /* During rtld init the memory is allocated by the stub malloc, prevent any attempt to free it by the normal malloc. */ l->l_runpath_dirs.malloced = 0; /* The RPATH is ignored. */ l->l_rpath_dirs.dirs = (void *) -1; } else { l->l_runpath_dirs.dirs = (void *) -1; if (l->l_info[DT_RPATH]) { /* Allocate room for the search path and fill in information from RPATH. */ decompose_rpath (&l->l_rpath_dirs, (const void *) (D_PTR (l, l_info[DT_STRTAB]) + l->l_info[DT_RPATH]->d_un.d_val), l, "RPATH"); /* During rtld init the memory is allocated by the stub malloc, prevent any attempt to free it by the normal malloc. */ l->l_rpath_dirs.malloced = 0; } else l->l_rpath_dirs.dirs = (void *) -1; } } #endif /* SHARED */ if (llp != NULL && *llp != '\0') { char *llp_tmp = strdupa (llp); /* Decompose the LD_LIBRARY_PATH contents. First determine how many elements it has. */ size_t nllp = 1; for (const char *cp = llp_tmp; *cp != '\0'; ++cp) if (*cp == ':' || *cp == ';') ++nllp; __rtld_env_path_list.dirs = (struct r_search_path_elem **) malloc ((nllp + 1) * sizeof (struct r_search_path_elem *)); if (__rtld_env_path_list.dirs == NULL) { errstring = N_("cannot create cache for search path"); goto signal_error; } (void) fillin_rpath (llp_tmp, __rtld_env_path_list.dirs, ":;", source, NULL, l); if (__rtld_env_path_list.dirs[0] == NULL) { free (__rtld_env_path_list.dirs); __rtld_env_path_list.dirs = (void *) -1; } __rtld_env_path_list.malloced = 0; } else __rtld_env_path_list.dirs = (void *) -1; } /* Process PT_GNU_PROPERTY program header PH in module L after PT_LOAD segments are mapped. Only one NT_GNU_PROPERTY_TYPE_0 note is handled which contains processor specific properties. FD is -1 for the kernel mapped main executable otherwise it is the fd used for loading module L. */ void _dl_process_pt_gnu_property (struct link_map *l, int fd, const ElfW(Phdr) *ph) { const ElfW(Nhdr) *note = (const void *) (ph->p_vaddr + l->l_addr); const ElfW(Addr) size = ph->p_memsz; const ElfW(Addr) align = ph->p_align; /* The NT_GNU_PROPERTY_TYPE_0 note must be aligned to 4 bytes in 32-bit objects and to 8 bytes in 64-bit objects. Skip notes with incorrect alignment. */ if (align != (__ELF_NATIVE_CLASS / 8)) return; const ElfW(Addr) start = (ElfW(Addr)) note; unsigned int last_type = 0; while ((ElfW(Addr)) (note + 1) - start < size) { /* Find the NT_GNU_PROPERTY_TYPE_0 note. */ if (note->n_namesz == 4 && note->n_type == NT_GNU_PROPERTY_TYPE_0 && memcmp (note + 1, "GNU", 4) == 0) { /* Check for invalid property. */ if (note->n_descsz < 8 || (note->n_descsz % sizeof (ElfW(Addr))) != 0) return; /* Start and end of property array. */ unsigned char *ptr = (unsigned char *) (note + 1) + 4; unsigned char *ptr_end = ptr + note->n_descsz; do { unsigned int type = *(unsigned int *) ptr; unsigned int datasz = *(unsigned int *) (ptr + 4); /* Property type must be in ascending order. */ if (type < last_type) return; ptr += 8; if ((ptr + datasz) > ptr_end) return; last_type = type; /* Target specific property processing. */ if (_dl_process_gnu_property (l, fd, type, datasz, ptr) == 0) return; /* Check the next property item. */ ptr += ALIGN_UP (datasz, sizeof (ElfW(Addr))); } while ((ptr_end - ptr) >= 8); /* Only handle one NT_GNU_PROPERTY_TYPE_0. */ return; } note = ((const void *) note + ELF_NOTE_NEXT_OFFSET (note->n_namesz, note->n_descsz, align)); } } /* Map in the shared object NAME, actually located in REALNAME, and already opened on FD. */ #ifndef EXTERNAL_MAP_FROM_FD static #endif 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) { struct link_map *l = NULL; const ElfW(Ehdr) *header; const ElfW(Phdr) *phdr; const ElfW(Phdr) *ph; size_t maplength; int type; /* Initialize to keep the compiler happy. */ const char *errstring = NULL; int errval = 0; struct r_debug *r = _dl_debug_initialize (0, nsid); bool make_consistent = false; /* Get file information. To match the kernel behavior, do not fill in this information for the executable in case of an explicit loader invocation. */ struct r_file_id id; if (mode & __RTLD_OPENEXEC) { assert (nsid == LM_ID_BASE); memset (&id, 0, sizeof (id)); } else { if (__glibc_unlikely (!_dl_get_file_id (fd, &id))) { errstring = N_("cannot stat shared object"); lose_errno: errval = errno; lose: /* The file might already be closed. */ if (fd != -1) __close_nocancel (fd); if (l != NULL && l->l_map_start != 0) _dl_unmap_segments (l); if (l != NULL && l->l_origin != (char *) -1l) free ((char *) l->l_origin); if (l != NULL && !l->l_libname->dont_free) free (l->l_libname); if (l != NULL && l->l_phdr_allocated) free ((void *) l->l_phdr); free (l); free (realname); if (make_consistent && r != NULL) { r->r_state = RT_CONSISTENT; _dl_debug_state (); LIBC_PROBE (map_failed, 2, nsid, r); } _dl_signal_error (errval, name, NULL, errstring); } /* Look again to see if the real name matched another already loaded. */ for (l = GL(dl_ns)[nsid]._ns_loaded; l != NULL; l = l->l_next) if (!l->l_removed && _dl_file_id_match_p (&l->l_file_id, &id)) { /* The object is already loaded. Just bump its reference count and return it. */ __close_nocancel (fd); /* If the name is not in the list of names for this object add it. */ free (realname); add_name_to_object (l, name); return l; } } #ifdef SHARED /* When loading into a namespace other than the base one we must avoid loading ld.so since there can only be one copy. Ever. */ if (__glibc_unlikely (nsid != LM_ID_BASE) && (_dl_file_id_match_p (&id, &GL(dl_rtld_map).l_file_id) || _dl_name_match_p (name, &GL(dl_rtld_map)))) { /* This is indeed ld.so. Create a new link_map which refers to the real one for almost everything. */ l = _dl_new_object (realname, name, l_type, loader, mode, nsid); if (l == NULL) goto fail_new; /* Refer to the real descriptor. */ l->l_real = &GL(dl_rtld_map); /* No need to bump the refcount of the real object, ld.so will never be unloaded. */ __close_nocancel (fd); /* Add the map for the mirrored object to the object list. */ _dl_add_to_namespace_list (l, nsid); return l; } #endif if (mode & RTLD_NOLOAD) { /* We are not supposed to load the object unless it is already loaded. So return now. */ free (realname); __close_nocancel (fd); return NULL; } /* Print debugging message. */ if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_FILES)) _dl_debug_printf ("file=%s [%lu]; generating link map\n", name, nsid); /* This is the ELF header. We read it in `open_verify'. */ header = (void *) fbp->buf; /* Signal that we are going to add new objects. */ if (r->r_state == RT_CONSISTENT) { #ifdef SHARED /* Auditing checkpoint: we are going to add new objects. */ if ((mode & __RTLD_AUDIT) == 0 && __glibc_unlikely (GLRO(dl_naudit) > 0)) { struct link_map *head = GL(dl_ns)[nsid]._ns_loaded; /* Do not call the functions for any auditing object. */ if (head->l_auditing == 0) { struct audit_ifaces *afct = GLRO(dl_audit); for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt) { if (afct->activity != NULL) afct->activity (&link_map_audit_state (head, cnt)->cookie, LA_ACT_ADD); afct = afct->next; } } } #endif /* Notify the debugger we have added some objects. We need to call _dl_debug_initialize in a static program in case dynamic linking has not been used before. */ r->r_state = RT_ADD; _dl_debug_state (); LIBC_PROBE (map_start, 2, nsid, r); make_consistent = true; } else assert (r->r_state == RT_ADD); /* Enter the new object in the list of loaded objects. */ l = _dl_new_object (realname, name, l_type, loader, mode, nsid); if (__glibc_unlikely (l == NULL)) { #ifdef SHARED fail_new: #endif errstring = N_("cannot create shared object descriptor"); goto lose_errno; } /* Extract the remaining details we need from the ELF header and then read in the program header table. */ l->l_entry = header->e_entry; type = header->e_type; l->l_phnum = header->e_phnum; maplength = header->e_phnum * sizeof (ElfW(Phdr)); if (header->e_phoff + maplength <= (size_t) fbp->len) phdr = (void *) (fbp->buf + header->e_phoff); else { phdr = alloca (maplength); if ((size_t) __pread64_nocancel (fd, (void *) phdr, maplength, header->e_phoff) != maplength) { errstring = N_("cannot read file data"); goto lose_errno; } } /* On most platforms presume that PT_GNU_STACK is absent and the stack is * executable. Other platforms default to a nonexecutable stack and don't * need PT_GNU_STACK to do so. */ uint_fast16_t stack_flags = DEFAULT_STACK_PERMS; { /* Scan the program header table, collecting its load commands. */ struct loadcmd loadcmds[l->l_phnum]; size_t nloadcmds = 0; bool has_holes = false; /* The struct is initialized to zero so this is not necessary: l->l_ld = 0; l->l_phdr = 0; l->l_addr = 0; */ for (ph = phdr; ph < &phdr[l->l_phnum]; ++ph) switch (ph->p_type) { /* These entries tell us where to find things once the file's segments are mapped in. We record the addresses it says verbatim, and later correct for the run-time load address. */ case PT_DYNAMIC: if (ph->p_filesz) { /* Debuginfo only files from "objcopy --only-keep-debug" contain a PT_DYNAMIC segment with p_filesz == 0. Skip such a segment to avoid a crash later. */ l->l_ld = (void *) ph->p_vaddr; l->l_ldnum = ph->p_memsz / sizeof (ElfW(Dyn)); } break; case PT_PHDR: l->l_phdr = (void *) ph->p_vaddr; break; case PT_LOAD: /* A load command tells us to map in part of the file. We record the load commands and process them all later. */ if (__glibc_unlikely ((ph->p_align & (GLRO(dl_pagesize) - 1)) != 0)) { errstring = N_("ELF load command alignment not page-aligned"); goto lose; } if (__glibc_unlikely (((ph->p_vaddr - ph->p_offset) & (ph->p_align - 1)) != 0)) { errstring = N_("ELF load command address/offset not properly aligned"); goto lose; } struct loadcmd *c = &loadcmds[nloadcmds++]; c->mapstart = ALIGN_DOWN (ph->p_vaddr, GLRO(dl_pagesize)); c->mapend = ALIGN_UP (ph->p_vaddr + ph->p_filesz, GLRO(dl_pagesize)); c->dataend = ph->p_vaddr + ph->p_filesz; c->allocend = ph->p_vaddr + ph->p_memsz; c->mapoff = ALIGN_DOWN (ph->p_offset, GLRO(dl_pagesize)); /* Determine whether there is a gap between the last segment and this one. */ if (nloadcmds > 1 && c[-1].mapend != c->mapstart) has_holes = true; /* Optimize a common case. */ #if (PF_R | PF_W | PF_X) == 7 && (PROT_READ | PROT_WRITE | PROT_EXEC) == 7 c->prot = (PF_TO_PROT >> ((ph->p_flags & (PF_R | PF_W | PF_X)) * 4)) & 0xf; #else c->prot = 0; if (ph->p_flags & PF_R) c->prot |= PROT_READ; if (ph->p_flags & PF_W) c->prot |= PROT_WRITE; if (ph->p_flags & PF_X) c->prot |= PROT_EXEC; #endif break; case PT_TLS: if (ph->p_memsz == 0) /* Nothing to do for an empty segment. */ break; l->l_tls_blocksize = ph->p_memsz; l->l_tls_align = ph->p_align; if (ph->p_align == 0) l->l_tls_firstbyte_offset = 0; else l->l_tls_firstbyte_offset = ph->p_vaddr & (ph->p_align - 1); l->l_tls_initimage_size = ph->p_filesz; /* Since we don't know the load address yet only store the offset. We will adjust it later. */ l->l_tls_initimage = (void *) ph->p_vaddr; /* l->l_tls_modid is assigned below, once there is no possibility for failure. */ if (l->l_type != lt_library && GL(dl_tls_dtv_slotinfo_list) == NULL) { #ifdef SHARED /* We are loading the executable itself when the dynamic linker was executed directly. The setup will happen later. */ assert (l->l_prev == NULL || (mode & __RTLD_AUDIT) != 0); #else assert (false && "TLS not initialized in static application"); #endif } break; case PT_GNU_STACK: stack_flags = ph->p_flags; break; case PT_GNU_RELRO: l->l_relro_addr = ph->p_vaddr; l->l_relro_size = ph->p_memsz; break; } if (__glibc_unlikely (nloadcmds == 0)) { /* This only happens for a bogus object that will be caught with another error below. But we don't want to go through the calculations below using NLOADCMDS - 1. */ errstring = N_("object file has no loadable segments"); goto lose; } /* dlopen of an executable is not valid because it is not possible to perform proper relocations, handle static TLS, or run the ELF constructors. For PIE, the check needs the dynamic section, so there is another check below. */ if (__glibc_unlikely (type != ET_DYN) && __glibc_unlikely ((mode & __RTLD_OPENEXEC) == 0)) { /* This object is loaded at a fixed address. This must never happen for objects loaded with dlopen. */ errstring = N_("cannot dynamically load executable"); goto lose; } /* Length of the sections to be loaded. */ maplength = loadcmds[nloadcmds - 1].allocend - loadcmds[0].mapstart; /* Now process the load commands and map segments into memory. This is responsible for filling in: l_map_start, l_map_end, l_addr, l_contiguous, l_text_end, l_phdr */ errstring = _dl_map_segments (l, fd, header, type, loadcmds, nloadcmds, maplength, has_holes, loader); if (__glibc_unlikely (errstring != NULL)) { /* Mappings can be in an inconsistent state: avoid unmap. */ l->l_map_start = l->l_map_end = 0; goto lose; } } if (l->l_ld == 0) { if (__glibc_unlikely (type == ET_DYN)) { errstring = N_("object file has no dynamic section"); goto lose; } } else l->l_ld = (ElfW(Dyn) *) ((ElfW(Addr)) l->l_ld + l->l_addr); elf_get_dynamic_info (l, NULL); /* Make sure we are not dlopen'ing an object that has the DF_1_NOOPEN flag set, or a PIE object. */ if ((__glibc_unlikely (l->l_flags_1 & DF_1_NOOPEN) && (mode & __RTLD_DLOPEN)) || (__glibc_unlikely (l->l_flags_1 & DF_1_PIE) && __glibc_unlikely ((mode & __RTLD_OPENEXEC) == 0))) { if (l->l_flags_1 & DF_1_PIE) errstring = N_("cannot dynamically load position-independent executable"); else errstring = N_("shared object cannot be dlopen()ed"); goto lose; } if (l->l_phdr == NULL) { /* The program header is not contained in any of the segments. We have to allocate memory ourself and copy it over from out temporary place. */ ElfW(Phdr) *newp = (ElfW(Phdr) *) malloc (header->e_phnum * sizeof (ElfW(Phdr))); if (newp == NULL) { errstring = N_("cannot allocate memory for program header"); goto lose_errno; } l->l_phdr = memcpy (newp, phdr, (header->e_phnum * sizeof (ElfW(Phdr)))); l->l_phdr_allocated = 1; } else /* Adjust the PT_PHDR value by the runtime load address. */ l->l_phdr = (ElfW(Phdr) *) ((ElfW(Addr)) l->l_phdr + l->l_addr); if (__glibc_unlikely ((stack_flags &~ GL(dl_stack_flags)) & PF_X)) { /* The stack is presently not executable, but this module requires that it be executable. We must change the protection of the variable which contains the flags used in the mprotect calls. */ #ifdef SHARED if ((mode & (__RTLD_DLOPEN | __RTLD_AUDIT)) == __RTLD_DLOPEN) { const uintptr_t p = (uintptr_t) &__stack_prot & -GLRO(dl_pagesize); const size_t s = (uintptr_t) (&__stack_prot + 1) - p; struct link_map *const m = &GL(dl_rtld_map); const uintptr_t relro_end = ((m->l_addr + m->l_relro_addr + m->l_relro_size) & -GLRO(dl_pagesize)); if (__glibc_likely (p + s <= relro_end)) { /* The variable lies in the region protected by RELRO. */ if (__mprotect ((void *) p, s, PROT_READ|PROT_WRITE) < 0) { errstring = N_("cannot change memory protections"); goto lose_errno; } __stack_prot |= PROT_READ|PROT_WRITE|PROT_EXEC; __mprotect ((void *) p, s, PROT_READ); } else __stack_prot |= PROT_READ|PROT_WRITE|PROT_EXEC; } else #endif __stack_prot |= PROT_READ|PROT_WRITE|PROT_EXEC; #ifdef check_consistency check_consistency (); #endif errval = (*GL(dl_make_stack_executable_hook)) (stack_endp); if (errval) { errstring = N_("\ cannot enable executable stack as shared object requires"); goto lose; } } /* Adjust the address of the TLS initialization image. */ if (l->l_tls_initimage != NULL) l->l_tls_initimage = (char *) l->l_tls_initimage + l->l_addr; /* Process program headers again after load segments are mapped in case processing requires accessing those segments. Scan program headers backward so that PT_NOTE can be skipped if PT_GNU_PROPERTY exits. */ for (ph = &l->l_phdr[l->l_phnum]; ph != l->l_phdr; --ph) switch (ph[-1].p_type) { case PT_NOTE: _dl_process_pt_note (l, fd, &ph[-1]); break; case PT_GNU_PROPERTY: _dl_process_pt_gnu_property (l, fd, &ph[-1]); break; } /* We are done mapping in the file. We no longer need the descriptor. */ if (__glibc_unlikely (__close_nocancel (fd) != 0)) { errstring = N_("cannot close file descriptor"); goto lose_errno; } /* Signal that we closed the file. */ fd = -1; /* Failures before this point are handled locally via lose. There are no more failures in this function until return, to change that the cleanup handling needs to be updated. */ /* If this is ET_EXEC, we should have loaded it as lt_executable. */ assert (type != ET_EXEC || l->l_type == lt_executable); l->l_entry += l->l_addr; if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_FILES)) _dl_debug_printf ("\ dynamic: 0x%0*lx base: 0x%0*lx size: 0x%0*Zx\n\ entry: 0x%0*lx phdr: 0x%0*lx phnum: %*u\n\n", (int) sizeof (void *) * 2, (unsigned long int) l->l_ld, (int) sizeof (void *) * 2, (unsigned long int) l->l_addr, (int) sizeof (void *) * 2, maplength, (int) sizeof (void *) * 2, (unsigned long int) l->l_entry, (int) sizeof (void *) * 2, (unsigned long int) l->l_phdr, (int) sizeof (void *) * 2, l->l_phnum); /* Set up the symbol hash table. */ _dl_setup_hash (l); /* If this object has DT_SYMBOLIC set modify now its scope. We don't have to do this for the main map. */ if ((mode & RTLD_DEEPBIND) == 0 && __glibc_unlikely (l->l_info[DT_SYMBOLIC] != NULL) && &l->l_searchlist != l->l_scope[0]) { /* Create an appropriate searchlist. It contains only this map. This is the definition of DT_SYMBOLIC in SysVr4. */ l->l_symbolic_searchlist.r_list[0] = l; l->l_symbolic_searchlist.r_nlist = 1; /* Now move the existing entries one back. */ memmove (&l->l_scope[1], &l->l_scope[0], (l->l_scope_max - 1) * sizeof (l->l_scope[0])); /* Now add the new entry. */ l->l_scope[0] = &l->l_symbolic_searchlist; } /* Remember whether this object must be initialized first. */ if (l->l_flags_1 & DF_1_INITFIRST) GL(dl_initfirst) = l; /* Finally the file information. */ l->l_file_id = id; #ifdef SHARED /* When auditing is used the recorded names might not include the name by which the DSO is actually known. Add that as well. */ if (__glibc_unlikely (origname != NULL)) add_name_to_object (l, origname); #else /* Audit modules only exist when linking is dynamic so ORIGNAME cannot be non-NULL. */ assert (origname == NULL); #endif /* When we profile the SONAME might be needed for something else but loading. Add it right away. */ if (__glibc_unlikely (GLRO(dl_profile) != NULL) && l->l_info[DT_SONAME] != NULL) add_name_to_object (l, ((const char *) D_PTR (l, l_info[DT_STRTAB]) + l->l_info[DT_SONAME]->d_un.d_val)); /* If we have newly loaded libc.so, update the namespace description. */ if (GL(dl_ns)[nsid].libc_map == NULL && l->l_info[DT_SONAME] != NULL && strcmp (((const char *) D_PTR (l, l_info[DT_STRTAB]) + l->l_info[DT_SONAME]->d_un.d_val), LIBC_SO) == 0) GL(dl_ns)[nsid].libc_map = l; /* _dl_close can only eventually undo the module ID assignment (via remove_slotinfo) if this function returns a pointer to a link map. Therefore, delay this step until all possibilities for failure have been excluded. */ if (l->l_tls_blocksize > 0 && (__glibc_likely (l->l_type == lt_library) /* If GL(dl_tls_dtv_slotinfo_list) == NULL, then rtld.c did not set up TLS data structures, so don't use them now. */ || __glibc_likely (GL(dl_tls_dtv_slotinfo_list) != NULL))) /* Assign the next available module ID. */ l->l_tls_modid = _dl_next_tls_modid (); #ifdef DL_AFTER_LOAD DL_AFTER_LOAD (l); #endif /* Now that the object is fully initialized add it to the object list. */ _dl_add_to_namespace_list (l, nsid); #ifdef SHARED /* Auditing checkpoint: we have a new object. */ if (__glibc_unlikely (GLRO(dl_naudit) > 0) && !GL(dl_ns)[l->l_ns]._ns_loaded->l_auditing) { struct audit_ifaces *afct = GLRO(dl_audit); for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt) { if (afct->objopen != NULL) { struct auditstate *state = link_map_audit_state (l, cnt); state->bindflags = afct->objopen (l, nsid, &state->cookie); l->l_audit_any_plt |= state->bindflags != 0; } afct = afct->next; } } #endif return l; } /* Print search path. */ static void print_search_path (struct r_search_path_elem **list, const char *what, const char *name) { char buf[max_dirnamelen + max_capstrlen]; int first = 1; _dl_debug_printf (" search path="); while (*list != NULL && (*list)->what == what) /* Yes, ==. */ { char *endp = __mempcpy (buf, (*list)->dirname, (*list)->dirnamelen); size_t cnt; for (cnt = 0; cnt < ncapstr; ++cnt) if ((*list)->status[cnt] != nonexisting) { #ifdef SHARED char *cp = __mempcpy (endp, capstr[cnt].str, capstr[cnt].len); if (cp == buf || (cp == buf + 1 && buf[0] == '/')) cp[0] = '\0'; else cp[-1] = '\0'; #else *endp = '\0'; #endif _dl_debug_printf_c (first ? "%s" : ":%s", buf); first = 0; } ++list; } if (name != NULL) _dl_debug_printf_c ("\t\t(%s from file %s)\n", what, DSO_FILENAME (name)); else _dl_debug_printf_c ("\t\t(%s)\n", what); } /* Open a file and verify it is an ELF file for this architecture. We ignore only ELF files for other architectures. Non-ELF files and ELF files with different header information cause fatal errors since this could mean there is something wrong in the installation and the user might want to know about this. If FD is not -1, then the file is already open and FD refers to it. In that case, FD is consumed for both successful and error returns. */ 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) { /* This is the expected ELF header. */ #define ELF32_CLASS ELFCLASS32 #define ELF64_CLASS ELFCLASS64 #ifndef VALID_ELF_HEADER # define VALID_ELF_HEADER(hdr,exp,size) (memcmp (hdr, exp, size) == 0) # define VALID_ELF_OSABI(osabi) (osabi == ELFOSABI_SYSV) # define VALID_ELF_ABIVERSION(osabi,ver) (ver == 0) #elif defined MORE_ELF_HEADER_DATA MORE_ELF_HEADER_DATA; #endif static const unsigned char expected[EI_NIDENT] = { [EI_MAG0] = ELFMAG0, [EI_MAG1] = ELFMAG1, [EI_MAG2] = ELFMAG2, [EI_MAG3] = ELFMAG3, [EI_CLASS] = ELFW(CLASS), [EI_DATA] = byteorder, [EI_VERSION] = EV_CURRENT, [EI_OSABI] = ELFOSABI_SYSV, [EI_ABIVERSION] = 0 }; static const struct { ElfW(Word) vendorlen; ElfW(Word) datalen; ElfW(Word) type; char vendor[4]; } expected_note = { 4, 16, 1, "GNU" }; /* Initialize it to make the compiler happy. */ const char *errstring = NULL; int errval = 0; #ifdef SHARED /* Give the auditing libraries a chance. */ if (__glibc_unlikely (GLRO(dl_naudit) > 0) && whatcode != 0 && loader->l_auditing == 0) { const char *original_name = name; struct audit_ifaces *afct = GLRO(dl_audit); for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt) { if (afct->objsearch != NULL) { struct auditstate *state = link_map_audit_state (loader, cnt); name = afct->objsearch (name, &state->cookie, whatcode); if (name == NULL) /* Ignore the path. */ return -1; } afct = afct->next; } if (fd != -1 && name != original_name && strcmp (name, original_name)) { /* An audit library changed what we're supposed to open, so FD no longer matches it. */ __close_nocancel (fd); fd = -1; } } #endif if (fd == -1) /* Open the file. We always open files read-only. */ fd = __open64_nocancel (name, O_RDONLY | O_CLOEXEC); if (fd != -1) { ElfW(Ehdr) *ehdr; ElfW(Phdr) *phdr, *ph; ElfW(Word) *abi_note; ElfW(Word) *abi_note_malloced = NULL; unsigned int osversion; size_t maplength; /* We successfully opened the file. Now verify it is a file we can use. */ __set_errno (0); fbp->len = 0; assert (sizeof (fbp->buf) > sizeof (ElfW(Ehdr))); /* Read in the header. */ do { ssize_t retlen = __read_nocancel (fd, fbp->buf + fbp->len, sizeof (fbp->buf) - fbp->len); if (retlen <= 0) break; fbp->len += retlen; } while (__glibc_unlikely (fbp->len < sizeof (ElfW(Ehdr)))); /* This is where the ELF header is loaded. */ ehdr = (ElfW(Ehdr) *) fbp->buf; /* Now run the tests. */ if (__glibc_unlikely (fbp->len < (ssize_t) sizeof (ElfW(Ehdr)))) { errval = errno; errstring = (errval == 0 ? N_("file too short") : N_("cannot read file data")); lose: if (free_name) { char *realname = (char *) name; name = strdupa (realname); free (realname); } __close_nocancel (fd); _dl_signal_error (errval, name, NULL, errstring); } /* See whether the ELF header is what we expect. */ if (__glibc_unlikely (! VALID_ELF_HEADER (ehdr->e_ident, expected, EI_ABIVERSION) || !VALID_ELF_ABIVERSION (ehdr->e_ident[EI_OSABI], ehdr->e_ident[EI_ABIVERSION]) || memcmp (&ehdr->e_ident[EI_PAD], &expected[EI_PAD], EI_NIDENT - EI_PAD) != 0)) { /* Something is wrong. */ const Elf32_Word *magp = (const void *) ehdr->e_ident; if (*magp != #if BYTE_ORDER == LITTLE_ENDIAN ((ELFMAG0 << (EI_MAG0 * 8)) | (ELFMAG1 << (EI_MAG1 * 8)) | (ELFMAG2 << (EI_MAG2 * 8)) | (ELFMAG3 << (EI_MAG3 * 8))) #else ((ELFMAG0 << (EI_MAG3 * 8)) | (ELFMAG1 << (EI_MAG2 * 8)) | (ELFMAG2 << (EI_MAG1 * 8)) | (ELFMAG3 << (EI_MAG0 * 8))) #endif ) errstring = N_("invalid ELF header"); else if (ehdr->e_ident[EI_CLASS] != ELFW(CLASS)) { /* This is not a fatal error. On architectures where 32-bit and 64-bit binaries can be run this might happen. */ *found_other_class = true; goto close_and_out; } else if (ehdr->e_ident[EI_DATA] != byteorder) { if (BYTE_ORDER == BIG_ENDIAN) errstring = N_("ELF file data encoding not big-endian"); else errstring = N_("ELF file data encoding not little-endian"); } else if (ehdr->e_ident[EI_VERSION] != EV_CURRENT) errstring = N_("ELF file version ident does not match current one"); /* XXX We should be able so set system specific versions which are allowed here. */ else if (!VALID_ELF_OSABI (ehdr->e_ident[EI_OSABI])) errstring = N_("ELF file OS ABI invalid"); else if (!VALID_ELF_ABIVERSION (ehdr->e_ident[EI_OSABI], ehdr->e_ident[EI_ABIVERSION])) errstring = N_("ELF file ABI version invalid"); else if (memcmp (&ehdr->e_ident[EI_PAD], &expected[EI_PAD], EI_NIDENT - EI_PAD) != 0) errstring = N_("nonzero padding in e_ident"); else /* Otherwise we don't know what went wrong. */ errstring = N_("internal error"); goto lose; } if (__glibc_unlikely (ehdr->e_version != EV_CURRENT)) { errstring = N_("ELF file version does not match current one"); goto lose; } if (! __glibc_likely (elf_machine_matches_host (ehdr))) goto close_and_out; else if (__glibc_unlikely (ehdr->e_type != ET_DYN && ehdr->e_type != ET_EXEC)) { errstring = N_("only ET_DYN and ET_EXEC can be loaded"); goto lose; } else if (__glibc_unlikely (ehdr->e_phentsize != sizeof (ElfW(Phdr)))) { errstring = N_("ELF file's phentsize not the expected size"); goto lose; } maplength = ehdr->e_phnum * sizeof (ElfW(Phdr)); if (ehdr->e_phoff + maplength <= (size_t) fbp->len) phdr = (void *) (fbp->buf + ehdr->e_phoff); else { phdr = alloca (maplength); if ((size_t) __pread64_nocancel (fd, (void *) phdr, maplength, ehdr->e_phoff) != maplength) { read_error: errval = errno; errstring = N_("cannot read file data"); goto lose; } } if (__glibc_unlikely (elf_machine_reject_phdr_p (phdr, ehdr->e_phnum, fbp->buf, fbp->len, loader, fd))) goto close_and_out; /* Check .note.ABI-tag if present. */ for (ph = phdr; ph < &phdr[ehdr->e_phnum]; ++ph) if (ph->p_type == PT_NOTE && ph->p_filesz >= 32 && (ph->p_align == 4 || ph->p_align == 8)) { ElfW(Addr) size = ph->p_filesz; if (ph->p_offset + size <= (size_t) fbp->len) abi_note = (void *) (fbp->buf + ph->p_offset); else { /* Note: __libc_use_alloca is not usable here, because thread info may not have been set up yet. */ if (size < __MAX_ALLOCA_CUTOFF) abi_note = alloca (size); else { /* There could be multiple PT_NOTEs. */ abi_note_malloced = realloc (abi_note_malloced, size); if (abi_note_malloced == NULL) goto read_error; abi_note = abi_note_malloced; } if (__pread64_nocancel (fd, (void *) abi_note, size, ph->p_offset) != size) { free (abi_note_malloced); goto read_error; } } while (memcmp (abi_note, &expected_note, sizeof (expected_note))) { ElfW(Addr) note_size = ELF_NOTE_NEXT_OFFSET (abi_note[0], abi_note[1], ph->p_align); if (size - 32 < note_size) { size = 0; break; } size -= note_size; abi_note = (void *) abi_note + note_size; } if (size == 0) continue; osversion = (abi_note[5] & 0xff) * 65536 + (abi_note[6] & 0xff) * 256 + (abi_note[7] & 0xff); if (abi_note[4] != __ABI_TAG_OS || (GLRO(dl_osversion) && GLRO(dl_osversion) < osversion)) { close_and_out: __close_nocancel (fd); __set_errno (ENOENT); fd = -1; } break; } free (abi_note_malloced); } return fd; } /* Try to open NAME in one of the directories in *DIRSP. Return the fd, or -1. If successful, fill in *REALNAME with the malloc'd full directory name. If it turns out that none of the directories in *DIRSP exists, *DIRSP is replaced with (void *) -1, and the old value is free()d if MAY_FREE_DIRS is true. */ 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) { struct r_search_path_elem **dirs = sps->dirs; char *buf; int fd = -1; const char *current_what = NULL; int any = 0; if (__glibc_unlikely (dirs == NULL)) /* We're called before _dl_init_paths when loading the main executable given on the command line when rtld is run directly. */ return -1; buf = alloca (max_dirnamelen + max_capstrlen + namelen); do { struct r_search_path_elem *this_dir = *dirs; size_t buflen = 0; size_t cnt; char *edp; int here_any = 0; int err; /* If we are debugging the search for libraries print the path now if it hasn't happened now. */ if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_LIBS) && current_what != this_dir->what) { current_what = this_dir->what; print_search_path (dirs, current_what, this_dir->where); } edp = (char *) __mempcpy (buf, this_dir->dirname, this_dir->dirnamelen); for (cnt = 0; fd == -1 && cnt < ncapstr; ++cnt) { /* Skip this directory if we know it does not exist. */ if (this_dir->status[cnt] == nonexisting) continue; #ifdef SHARED buflen = ((char *) __mempcpy (__mempcpy (edp, capstr[cnt].str, capstr[cnt].len), name, namelen) - buf); #else buflen = (char *) __mempcpy (edp, name, namelen) - buf; #endif /* Print name we try if this is wanted. */ if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_LIBS)) _dl_debug_printf (" trying file=%s\n", buf); fd = open_verify (buf, -1, fbp, loader, whatcode, mode, found_other_class, false); if (this_dir->status[cnt] == unknown) { if (fd != -1) this_dir->status[cnt] = existing; /* Do not update the directory information when loading auditing code. We must try to disturb the program as little as possible. */ else if (loader == NULL || GL(dl_ns)[loader->l_ns]._ns_loaded->l_auditing == 0) { /* We failed to open machine dependent library. Let's test whether there is any directory at all. */ struct stat64 st; buf[buflen - namelen - 1] = '\0'; if (__stat64 (buf, &st) != 0 || ! S_ISDIR (st.st_mode)) /* The directory does not exist or it is no directory. */ this_dir->status[cnt] = nonexisting; else this_dir->status[cnt] = existing; } } /* Remember whether we found any existing directory. */ here_any |= this_dir->status[cnt] != nonexisting; if (fd != -1 && __glibc_unlikely (mode & __RTLD_SECURE) && __libc_enable_secure) { /* This is an extra security effort to make sure nobody can preload broken shared objects which are in the trusted directories and so exploit the bugs. */ struct stat64 st; if (__fstat64 (fd, &st) != 0 || (st.st_mode & S_ISUID) == 0) { /* The shared object cannot be tested for being SUID or this bit is not set. In this case we must not use this object. */ __close_nocancel (fd); fd = -1; /* We simply ignore the file, signal this by setting the error value which would have been set by `open'. */ errno = ENOENT; } } } if (fd != -1) { *realname = (char *) malloc (buflen); if (*realname != NULL) { memcpy (*realname, buf, buflen); return fd; } else { /* No memory for the name, we certainly won't be able to load and link it. */ __close_nocancel (fd); return -1; } } if (here_any && (err = errno) != ENOENT && err != EACCES) /* The file exists and is readable, but something went wrong. */ return -1; /* Remember whether we found anything. */ any |= here_any; } while (*++dirs != NULL); /* Remove the whole path if none of the directories exists. */ if (__glibc_unlikely (! any)) { /* Paths which were allocated using the minimal malloc() in ld.so must not be freed using the general free() in libc. */ if (sps->malloced) free (sps->dirs); /* __rtld_search_dirs and __rtld_env_path_list are attribute_relro, therefore avoid writing to them. */ if (sps != &__rtld_search_dirs && sps != &__rtld_env_path_list) sps->dirs = (void *) -1; } return -1; } /* Map in the shared object file NAME. */ struct link_map * _dl_map_object (struct link_map *loader, const char *name, int type, int trace_mode, int mode, Lmid_t nsid) { int fd; const char *origname = NULL; char *realname; char *name_copy; struct link_map *l; struct filebuf fb; assert (nsid >= 0); assert (nsid < GL(dl_nns)); /* Look for this name among those already loaded. */ for (l = GL(dl_ns)[nsid]._ns_loaded; l; l = l->l_next) { /* If the requested name matches the soname of a loaded object, use that object. Elide this check for names that have not yet been opened. */ if (__glibc_unlikely ((l->l_faked | l->l_removed) != 0)) continue; if (!_dl_name_match_p (name, l)) { const char *soname; if (__glibc_likely (l->l_soname_added) || l->l_info[DT_SONAME] == NULL) continue; soname = ((const char *) D_PTR (l, l_info[DT_STRTAB]) + l->l_info[DT_SONAME]->d_un.d_val); if (strcmp (name, soname) != 0) continue; /* We have a match on a new name -- cache it. */ add_name_to_object (l, soname); l->l_soname_added = 1; } /* We have a match. */ return l; } /* Display information if we are debugging. */ if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_FILES) && loader != NULL) _dl_debug_printf ((mode & __RTLD_CALLMAP) == 0 ? "\nfile=%s [%lu]; needed by %s [%lu]\n" : "\nfile=%s [%lu]; dynamically loaded by %s [%lu]\n", name, nsid, DSO_FILENAME (loader->l_name), loader->l_ns); #ifdef SHARED /* Give the auditing libraries a chance to change the name before we try anything. */ if (__glibc_unlikely (GLRO(dl_naudit) > 0) && (loader == NULL || loader->l_auditing == 0)) { struct audit_ifaces *afct = GLRO(dl_audit); for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt) { if (afct->objsearch != NULL) { const char *before = name; struct auditstate *state = link_map_audit_state (loader, cnt); name = afct->objsearch (name, &state->cookie, LA_SER_ORIG); if (name == NULL) { /* Do not try anything further. */ fd = -1; goto no_file; } if (before != name && strcmp (before, name) != 0) { if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_FILES)) _dl_debug_printf ("audit changed filename %s -> %s\n", before, name); if (origname == NULL) origname = before; } } afct = afct->next; } } #endif /* Will be true if we found a DSO which is of the other ELF class. */ bool found_other_class = false; if (strchr (name, '/') == NULL) { /* Search for NAME in several places. */ size_t namelen = strlen (name) + 1; if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_LIBS)) _dl_debug_printf ("find library=%s [%lu]; searching\n", name, nsid); fd = -1; /* When the object has the RUNPATH information we don't use any RPATHs. */ if (loader == NULL || loader->l_info[DT_RUNPATH] == NULL) { /* This is the executable's map (if there is one). Make sure that we do not look at it twice. */ struct link_map *main_map = GL(dl_ns)[LM_ID_BASE]._ns_loaded; bool did_main_map = false; /* First try the DT_RPATH of the dependent object that caused NAME to be loaded. Then that object's dependent, and on up. */ for (l = loader; l; l = l->l_loader) if (cache_rpath (l, &l->l_rpath_dirs, DT_RPATH, "RPATH")) { fd = open_path (name, namelen, mode, &l->l_rpath_dirs, &realname, &fb, loader, LA_SER_RUNPATH, &found_other_class); if (fd != -1) break; did_main_map |= l == main_map; } /* If dynamically linked, try the DT_RPATH of the executable itself. NB: we do this for lookups in any namespace. */ if (fd == -1 && !did_main_map && main_map != NULL && main_map->l_type != lt_loaded && cache_rpath (main_map, &main_map->l_rpath_dirs, DT_RPATH, "RPATH")) fd = open_path (name, namelen, mode, &main_map->l_rpath_dirs, &realname, &fb, loader ?: main_map, LA_SER_RUNPATH, &found_other_class); } /* Try the LD_LIBRARY_PATH environment variable. */ if (fd == -1 && __rtld_env_path_list.dirs != (void *) -1) fd = open_path (name, namelen, mode, &__rtld_env_path_list, &realname, &fb, loader ?: GL(dl_ns)[LM_ID_BASE]._ns_loaded, LA_SER_LIBPATH, &found_other_class); /* Look at the RUNPATH information for this binary. */ if (fd == -1 && loader != NULL && cache_rpath (loader, &loader->l_runpath_dirs, DT_RUNPATH, "RUNPATH")) fd = open_path (name, namelen, mode, &loader->l_runpath_dirs, &realname, &fb, loader, LA_SER_RUNPATH, &found_other_class); if (fd == -1) { realname = _dl_sysdep_open_object (name, namelen, &fd); if (realname != NULL) { fd = open_verify (realname, fd, &fb, loader ?: GL(dl_ns)[nsid]._ns_loaded, LA_SER_CONFIG, mode, &found_other_class, false); if (fd == -1) free (realname); } } #ifdef USE_LDCONFIG if (fd == -1 && (__glibc_likely ((mode & __RTLD_SECURE) == 0) || ! __libc_enable_secure) && __glibc_likely (GLRO(dl_inhibit_cache) == 0)) { /* Check the list of libraries in the file /etc/ld.so.cache, for compatibility with Linux's ldconfig program. */ char *cached = _dl_load_cache_lookup (name); if (cached != NULL) { // XXX Correct to unconditionally default to namespace 0? l = (loader ?: GL(dl_ns)[LM_ID_BASE]._ns_loaded # ifdef SHARED ?: &GL(dl_rtld_map) # endif ); /* If the loader has the DF_1_NODEFLIB flag set we must not use a cache entry from any of these directories. */ if (__glibc_unlikely (l->l_flags_1 & DF_1_NODEFLIB)) { const char *dirp = system_dirs; unsigned int cnt = 0; do { if (memcmp (cached, dirp, system_dirs_len[cnt]) == 0) { /* The prefix matches. Don't use the entry. */ free (cached); cached = NULL; break; } dirp += system_dirs_len[cnt] + 1; ++cnt; } while (cnt < nsystem_dirs_len); } if (cached != NULL) { fd = open_verify (cached, -1, &fb, loader ?: GL(dl_ns)[nsid]._ns_loaded, LA_SER_CONFIG, mode, &found_other_class, false); if (__glibc_likely (fd != -1)) realname = cached; else free (cached); } } } #endif /* Finally, try the default path. */ if (fd == -1 && ((l = loader ?: GL(dl_ns)[nsid]._ns_loaded) == NULL || __glibc_likely (!(l->l_flags_1 & DF_1_NODEFLIB))) && __rtld_search_dirs.dirs != (void *) -1) fd = open_path (name, namelen, mode, &__rtld_search_dirs, &realname, &fb, l, LA_SER_DEFAULT, &found_other_class); /* Add another newline when we are tracing the library loading. */ if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_LIBS)) _dl_debug_printf ("\n"); } else { /* The path may contain dynamic string tokens. */ realname = (loader ? expand_dynamic_string_token (loader, name) : __strdup (name)); if (realname == NULL) fd = -1; else { fd = open_verify (realname, -1, &fb, loader ?: GL(dl_ns)[nsid]._ns_loaded, 0, mode, &found_other_class, true); if (__glibc_unlikely (fd == -1)) free (realname); } } #ifdef SHARED no_file: #endif /* In case the LOADER information has only been provided to get to the appropriate RUNPATH/RPATH information we do not need it anymore. */ if (mode & __RTLD_CALLMAP) loader = NULL; if (__glibc_unlikely (fd == -1)) { if (trace_mode && __glibc_likely ((GLRO(dl_debug_mask) & DL_DEBUG_PRELINK) == 0)) { /* We haven't found an appropriate library. But since we are only interested in the list of libraries this isn't so severe. Fake an entry with all the information we have. */ static const Elf_Symndx dummy_bucket = STN_UNDEF; /* Allocate a new object map. */ if ((name_copy = __strdup (name)) == NULL || (l = _dl_new_object (name_copy, name, type, loader, mode, nsid)) == NULL) { free (name_copy); _dl_signal_error (ENOMEM, name, NULL, N_("cannot create shared object descriptor")); } /* Signal that this is a faked entry. */ l->l_faked = 1; /* Since the descriptor is initialized with zero we do not have do this here. l->l_reserved = 0; */ l->l_buckets = &dummy_bucket; l->l_nbuckets = 1; l->l_relocated = 1; /* Enter the object in the object list. */ _dl_add_to_namespace_list (l, nsid); return l; } else if (found_other_class) _dl_signal_error (0, name, NULL, ELFW(CLASS) == ELFCLASS32 ? N_("wrong ELF class: ELFCLASS64") : N_("wrong ELF class: ELFCLASS32")); else _dl_signal_error (errno, name, NULL, N_("cannot open shared object file")); } void *stack_end = __libc_stack_end; return _dl_map_object_from_fd (name, origname, fd, &fb, realname, loader, type, mode, &stack_end, nsid); } struct add_path_state { bool counting; unsigned int idx; Dl_serinfo *si; char *allocptr; }; static void add_path (struct add_path_state *p, const struct r_search_path_struct *sps, unsigned int flags) { if (sps->dirs != (void *) -1) { struct r_search_path_elem **dirs = sps->dirs; do { const struct r_search_path_elem *const r = *dirs++; if (p->counting) { p->si->dls_cnt++; p->si->dls_size += MAX (2, r->dirnamelen); } else { Dl_serpath *const sp = &p->si->dls_serpath[p->idx++]; sp->dls_name = p->allocptr; if (r->dirnamelen < 2) *p->allocptr++ = r->dirnamelen ? '/' : '.'; else p->allocptr = __mempcpy (p->allocptr, r->dirname, r->dirnamelen - 1); *p->allocptr++ = '\0'; sp->dls_flags = flags; } } while (*dirs != NULL); } } void _dl_rtld_di_serinfo (struct link_map *loader, Dl_serinfo *si, bool counting) { if (counting) { si->dls_cnt = 0; si->dls_size = 0; } struct add_path_state p = { .counting = counting, .idx = 0, .si = si, .allocptr = (char *) &si->dls_serpath[si->dls_cnt] }; # define add_path(p, sps, flags) add_path(p, sps, 0) /* XXX */ /* When the object has the RUNPATH information we don't use any RPATHs. */ if (loader->l_info[DT_RUNPATH] == NULL) { /* First try the DT_RPATH of the dependent object that caused NAME to be loaded. Then that object's dependent, and on up. */ struct link_map *l = loader; do { if (cache_rpath (l, &l->l_rpath_dirs, DT_RPATH, "RPATH")) add_path (&p, &l->l_rpath_dirs, XXX_RPATH); l = l->l_loader; } while (l != NULL); /* If dynamically linked, try the DT_RPATH of the executable itself. */ if (loader->l_ns == LM_ID_BASE) { l = GL(dl_ns)[LM_ID_BASE]._ns_loaded; if (l != NULL && l->l_type != lt_loaded && l != loader) if (cache_rpath (l, &l->l_rpath_dirs, DT_RPATH, "RPATH")) add_path (&p, &l->l_rpath_dirs, XXX_RPATH); } } /* Try the LD_LIBRARY_PATH environment variable. */ add_path (&p, &__rtld_env_path_list, XXX_ENV); /* Look at the RUNPATH information for this binary. */ if (cache_rpath (loader, &loader->l_runpath_dirs, DT_RUNPATH, "RUNPATH")) add_path (&p, &loader->l_runpath_dirs, XXX_RUNPATH); /* XXX Here is where ld.so.cache gets checked, but we don't have a way to indicate that in the results for Dl_serinfo. */ /* Finally, try the default path. */ if (!(loader->l_flags_1 & DF_1_NODEFLIB)) add_path (&p, &__rtld_search_dirs, XXX_default); if (counting) /* Count the struct size before the string area, which we didn't know before we completed dls_cnt. */ si->dls_size += (char *) &si->dls_serpath[si->dls_cnt] - (char *) si; }