Partial backport of: commit a42faf59d6d9f82e5293a9ebcc26d9c9e562b12b Author: Paul Pluzhnikov Date: Mon Mar 24 10:58:26 2014 -0700 Fix BZ #16634. An application that erroneously tries to repeatedly dlopen("a.out", ...) may hit assertion failure: Inconsistency detected by ld.so: dl-tls.c: 474: _dl_allocate_tls_init: Assertion `listp != ((void *)0)' failed! dlopen() actually fails with "./a.out: cannot dynamically load executable", but it does so after incrementing dl_tls_max_dtv_idx. Once we run out of TLS_SLOTINFO_SURPLUS (62), we exit with above assertion failure. 2014-03-24 Paul Pluzhnikov [BZ #16634] * elf/dl-load.c (open_verify): Add mode parameter. Error early when ET_EXEC and mode does not have __RTLD_OPENEXEC. (open_path): Change from boolean 'secure' to complete flag 'mode' (_dl_map_object): Adjust. * elf/Makefile (tests): Add tst-dlopen-aout. * elf/tst-dlopen-aout.c: New test. Only the change to elf/dl-load.c is included here. The upstream test does not work because it depends on --enable-hardcoded-path-in-tests (which is not available in this tree, despite being documented in the manual). diff --git a/elf/dl-load.c b/elf/dl-load.c index 6a0005da502c8f37..0ba0712aa5201fa0 100644 --- a/elf/dl-load.c +++ b/elf/dl-load.c @@ -1686,7 +1686,7 @@ print_search_path (struct r_search_path_elem **list, user might want to know about this. */ static int open_verify (const char *name, struct filebuf *fbp, struct link_map *loader, - int whatcode, bool *found_other_class, bool free_name) + int whatcode, int mode, bool *found_other_class, bool free_name) { /* This is the expected ELF header. */ #define ELF32_CLASS ELFCLASS32 @@ -1863,6 +1863,17 @@ open_verify (const char *name, struct filebuf *fbp, struct link_map *loader, errstring = N_("only ET_DYN and ET_EXEC can be loaded"); goto call_lose; } + else if (__glibc_unlikely (ehdr->e_type == ET_EXEC + && (mode & __RTLD_OPENEXEC) == 0)) + { + /* BZ #16634. It is an error to dlopen ET_EXEC (unless + __RTLD_OPENEXEC is explicitly set). We return error here + so that code in _dl_map_object_from_fd does not try to set + l_tls_modid for this module. */ + + errstring = N_("cannot dynamically load executable"); + goto call_lose; + } else if (__builtin_expect (ehdr->e_phentsize, sizeof (ElfW(Phdr))) != sizeof (ElfW(Phdr))) { @@ -1964,7 +1975,7 @@ open_verify (const char *name, struct filebuf *fbp, struct link_map *loader, if MAY_FREE_DIRS is true. */ static int -open_path (const char *name, size_t namelen, int secure, +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) @@ -2016,8 +2027,8 @@ open_path (const char *name, size_t namelen, int secure, if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_LIBS, 0)) _dl_debug_printf (" trying file=%s\n", buf); - fd = open_verify (buf, fbp, loader, whatcode, found_other_class, - false); + fd = open_verify (buf, fbp, loader, whatcode, mode, + found_other_class, false); if (this_dir->status[cnt] == unknown) { if (fd != -1) @@ -2046,7 +2057,7 @@ open_path (const char *name, size_t namelen, int secure, /* Remember whether we found any existing directory. */ here_any |= this_dir->status[cnt] != nonexisting; - if (fd != -1 && __builtin_expect (secure, 0) + if (fd != -1 && __builtin_expect (mode & __RTLD_SECURE, 0) && INTUSE(__libc_enable_secure)) { /* This is an extra security effort to make sure nobody can @@ -2236,7 +2247,7 @@ _dl_map_object (struct link_map *loader, const char *name, 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 & __RTLD_SECURE, + fd = open_path (name, namelen, mode, &l->l_rpath_dirs, &realname, &fb, loader, LA_SER_RUNPATH, &found_other_class); @@ -2252,7 +2263,7 @@ _dl_map_object (struct link_map *loader, const char *name, && 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 & __RTLD_SECURE, + fd = open_path (name, namelen, mode, &main_map->l_rpath_dirs, &realname, &fb, loader ?: main_map, LA_SER_RUNPATH, &found_other_class); @@ -2260,7 +2271,7 @@ _dl_map_object (struct link_map *loader, const char *name, /* Try the LD_LIBRARY_PATH environment variable. */ if (fd == -1 && env_path_list.dirs != (void *) -1) - fd = open_path (name, namelen, mode & __RTLD_SECURE, &env_path_list, + fd = open_path (name, namelen, mode, &env_path_list, &realname, &fb, loader ?: GL(dl_ns)[LM_ID_BASE]._ns_loaded, LA_SER_LIBPATH, &found_other_class); @@ -2269,7 +2280,7 @@ _dl_map_object (struct link_map *loader, const char *name, if (fd == -1 && loader != NULL && cache_rpath (loader, &loader->l_runpath_dirs, DT_RUNPATH, "RUNPATH")) - fd = open_path (name, namelen, mode & __RTLD_SECURE, + fd = open_path (name, namelen, mode, &loader->l_runpath_dirs, &realname, &fb, loader, LA_SER_RUNPATH, &found_other_class); @@ -2326,7 +2337,8 @@ _dl_map_object (struct link_map *loader, const char *name, { fd = open_verify (cached, &fb, loader ?: GL(dl_ns)[nsid]._ns_loaded, - LA_SER_CONFIG, &found_other_class, false); + LA_SER_CONFIG, mode, &found_other_class, + false); if (__builtin_expect (fd != -1, 1)) realname = cached; else @@ -2341,7 +2353,7 @@ _dl_map_object (struct link_map *loader, const char *name, && ((l = loader ?: GL(dl_ns)[nsid]._ns_loaded) == NULL || __builtin_expect (!(l->l_flags_1 & DF_1_NODEFLIB), 1)) && rtld_search_dirs.dirs != (void *) -1) - fd = open_path (name, namelen, mode & __RTLD_SECURE, &rtld_search_dirs, + 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. */ @@ -2359,7 +2371,7 @@ _dl_map_object (struct link_map *loader, const char *name, else { fd = open_verify (realname, &fb, - loader ?: GL(dl_ns)[nsid]._ns_loaded, 0, + loader ?: GL(dl_ns)[nsid]._ns_loaded, 0, mode, &found_other_class, true); if (__builtin_expect (fd, 0) == -1) free (realname);