Partial backport of:
commit a42faf59d6d9f82e5293a9ebcc26d9c9e562b12b
Author: Paul Pluzhnikov <ppluzhnikov@google.com>
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 <ppluzhnikov@google.com>
[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);