# http://seclists.org/fulldisclosure/2010/Oct/344 # http://sourceware.org/ml/libc-hacker/2010-10/msg00010.html 2010-10-22 Andreas Schwab * include/dlfcn.h (__RTLD_SECURE): Define. * elf/dl-load.c (_dl_map_object): Remove preloaded parameter. Use mode & __RTLD_SECURE instead. (open_path): Rename preloaded parameter to secure. * sysdeps/generic/ldsodefs.h (_dl_map_object): Adjust declaration. * elf/dl-open.c (dl_open_worker): Adjust call to _dl_map_object. * elf/dl-deps.c (openaux): Likewise. * elf/rtld.c (struct map_args): Remove is_preloaded. (map_doit): Don't use it. (dl_main): Likewise. (do_preload): Use __RTLD_SECURE instead of is_preloaded. (dlmopen_doit): Add __RTLD_SECURE to mode bits. --- elf/dl-deps.c | 2 +- elf/dl-load.c | 20 +++++++++++--------- elf/dl-open.c | 2 +- elf/rtld.c | 16 +++++++--------- include/dlfcn.h | 1 + sysdeps/generic/ldsodefs.h | 6 ++---- 6 files changed, 23 insertions(+), 24 deletions(-) diff --git a/elf/dl-deps.c b/elf/dl-deps.c index e5b9cdf..1cab2d1 100644 --- a/elf/dl-deps.c +++ b/elf/dl-deps.c @@ -62,7 +62,7 @@ openaux (void *a) { struct openaux_args *args = (struct openaux_args *) a; - args->aux = _dl_map_object (args->map, args->name, 0, + args->aux = _dl_map_object (args->map, args->name, (args->map->l_type == lt_executable ? lt_library : args->map->l_type), args->trace_mode, args->open_mode, diff --git a/elf/dl-load.c b/elf/dl-load.c index 776f7e4..9ab3520 100644 --- a/elf/dl-load.c +++ b/elf/dl-load.c @@ -1808,7 +1808,7 @@ 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 preloaded, +open_path (const char *name, size_t namelen, int secure, struct r_search_path_struct *sps, char **realname, struct filebuf *fbp, struct link_map *loader, int whatcode, bool *found_other_class) @@ -1890,7 +1890,7 @@ open_path (const char *name, size_t namelen, int preloaded, /* Remember whether we found any existing directory. */ here_any |= this_dir->status[cnt] != nonexisting; - if (fd != -1 && __builtin_expect (preloaded, 0) + if (fd != -1 && __builtin_expect (secure, 0) && INTUSE(__libc_enable_secure)) { /* This is an extra security effort to make sure nobody can @@ -1959,7 +1959,7 @@ open_path (const char *name, size_t namelen, int preloaded, struct link_map * internal_function -_dl_map_object (struct link_map *loader, const char *name, int preloaded, +_dl_map_object (struct link_map *loader, const char *name, int type, int trace_mode, int mode, Lmid_t nsid) { int fd; @@ -2063,7 +2063,8 @@ _dl_map_object (struct link_map *loader, const char *name, int preloaded, for (l = loader; l; l = l->l_loader) if (cache_rpath (l, &l->l_rpath_dirs, DT_RPATH, "RPATH")) { - fd = open_path (name, namelen, preloaded, &l->l_rpath_dirs, + fd = open_path (name, namelen, mode & __RTLD_SECURE, + &l->l_rpath_dirs, &realname, &fb, loader, LA_SER_RUNPATH, &found_other_class); if (fd != -1) @@ -2078,14 +2079,15 @@ _dl_map_object (struct link_map *loader, const char *name, int preloaded, && 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, preloaded, &main_map->l_rpath_dirs, + fd = open_path (name, namelen, mode & __RTLD_SECURE, + &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 && env_path_list.dirs != (void *) -1) - fd = open_path (name, namelen, preloaded, &env_path_list, + fd = open_path (name, namelen, mode & __RTLD_SECURE, &env_path_list, &realname, &fb, loader ?: GL(dl_ns)[LM_ID_BASE]._ns_loaded, LA_SER_LIBPATH, &found_other_class); @@ -2094,12 +2096,12 @@ _dl_map_object (struct link_map *loader, const char *name, int preloaded, if (fd == -1 && loader != NULL && cache_rpath (loader, &loader->l_runpath_dirs, DT_RUNPATH, "RUNPATH")) - fd = open_path (name, namelen, preloaded, + fd = open_path (name, namelen, mode & __RTLD_SECURE, &loader->l_runpath_dirs, &realname, &fb, loader, LA_SER_RUNPATH, &found_other_class); if (fd == -1 - && (__builtin_expect (! preloaded, 1) + && (__builtin_expect (! (mode & __RTLD_SECURE), 1) || ! INTUSE(__libc_enable_secure))) { /* Check the list of libraries in the file /etc/ld.so.cache, @@ -2165,7 +2167,7 @@ _dl_map_object (struct link_map *loader, const char *name, int preloaded, && ((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, preloaded, &rtld_search_dirs, + fd = open_path (name, namelen, mode & __RTLD_SECURE, &rtld_search_dirs, &realname, &fb, l, LA_SER_DEFAULT, &found_other_class); /* Add another newline when we are tracing the library loading. */ diff --git a/elf/dl-open.c b/elf/dl-open.c index c394b3f..cf8e8cc 100644 --- a/elf/dl-open.c +++ b/elf/dl-open.c @@ -223,7 +223,7 @@ dl_open_worker (void *a) /* Load the named object. */ struct link_map *new; - args->map = new = _dl_map_object (call_map, file, 0, lt_loaded, 0, + args->map = new = _dl_map_object (call_map, file, lt_loaded, 0, mode | __RTLD_CALLMAP, args->nsid); /* If the pointer returned is NULL this means the RTLD_NOLOAD flag is diff --git a/elf/rtld.c b/elf/rtld.c index 201c9cf..4a8cee8 100644 --- a/elf/rtld.c +++ b/elf/rtld.c @@ -587,7 +587,6 @@ struct map_args /* Argument to map_doit. */ char *str; struct link_map *loader; - int is_preloaded; int mode; /* Return value of map_doit. */ struct link_map *map; @@ -625,16 +624,17 @@ static void map_doit (void *a) { struct map_args *args = (struct map_args *) a; - args->map = _dl_map_object (args->loader, args->str, - args->is_preloaded, lt_library, 0, args->mode, - LM_ID_BASE); + args->map = _dl_map_object (args->loader, args->str, lt_library, 0, + args->mode, LM_ID_BASE); } static void dlmopen_doit (void *a) { struct dlmopen_args *args = (struct dlmopen_args *) a; - args->map = _dl_open (args->fname, RTLD_LAZY | __RTLD_DLOPEN | __RTLD_AUDIT, + args->map = _dl_open (args->fname, + (RTLD_LAZY | __RTLD_DLOPEN | __RTLD_AUDIT + | __RTLD_SECURE), dl_main, LM_ID_NEWLM, _dl_argc, INTUSE(_dl_argv), __environ); } @@ -804,8 +804,7 @@ do_preload (char *fname, struct link_map *main_map, const char *where) args.str = fname; args.loader = main_map; - args.is_preloaded = 1; - args.mode = 0; + args.mode = __RTLD_SECURE; unsigned int old_nloaded = GL(dl_ns)[LM_ID_BASE]._ns_nloaded; @@ -1050,7 +1049,6 @@ of this helper program; chances are you did not intend to run this program.\n\ args.str = rtld_progname; args.loader = NULL; - args.is_preloaded = 0; args.mode = __RTLD_OPENEXEC; (void) _dl_catch_error (&objname, &err_str, &malloced, map_doit, &args); @@ -1062,7 +1060,7 @@ of this helper program; chances are you did not intend to run this program.\n\ else { HP_TIMING_NOW (start); - _dl_map_object (NULL, rtld_progname, 0, lt_library, 0, + _dl_map_object (NULL, rtld_progname, lt_library, 0, __RTLD_OPENEXEC, LM_ID_BASE); HP_TIMING_NOW (stop); diff --git a/include/dlfcn.h b/include/dlfcn.h index a67426d..af92483 100644 --- a/include/dlfcn.h +++ b/include/dlfcn.h @@ -9,6 +9,7 @@ #define __RTLD_OPENEXEC 0x20000000 #define __RTLD_CALLMAP 0x10000000 #define __RTLD_AUDIT 0x08000000 +#define __RTLD_SECURE 0x04000000 /* Apply additional security checks. */ #define __LM_ID_CALLER -2 diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h index fcc943b..fa4b6b2 100644 --- a/sysdeps/generic/ldsodefs.h +++ b/sysdeps/generic/ldsodefs.h @@ -824,11 +824,9 @@ extern void _dl_receive_error (receiver_fct fct, void (*operate) (void *), /* Open the shared object NAME and map in its segments. LOADER's DT_RPATH is used in searching for NAME. - If the object is already opened, returns its existing map. - For preloaded shared objects PRELOADED is set to a non-zero - value to allow additional security checks. */ + If the object is already opened, returns its existing map. */ extern struct link_map *_dl_map_object (struct link_map *loader, - const char *name, int preloaded, + const char *name, int type, int trace_mode, int mode, Lmid_t nsid) internal_function attribute_hidden;