99 lines
3.7 KiB
Diff
99 lines
3.7 KiB
Diff
commit 9ffa50b26b0cb5d3043adf6d3d0b1ea735acc147
|
|
Author: Florian Weimer <fweimer@redhat.com>
|
|
Date: Fri Dec 11 17:30:03 2020 +0100
|
|
|
|
elf: Include libc.so.6 as main program in dependency sort (bug 20972)
|
|
|
|
_dl_map_object_deps always sorts the initially loaded object first
|
|
during dependency sorting. This means it is relocated last in
|
|
dl_open_worker. This results in crashes in IFUNC resolvers without
|
|
lazy bindings if libraries are preloaded that refer to IFUNCs in
|
|
libc.so.6: the resolvers are called when libc.so.6 has not been
|
|
relocated yet, so references to _rtld_global_ro etc. crash.
|
|
|
|
The fix is to check against the libc.so.6 link map recorded by the
|
|
__libc_early_init framework, and let it participate in the dependency
|
|
sort.
|
|
|
|
This fixes bug 20972.
|
|
|
|
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
|
|
|
|
Conflicts:
|
|
elf/Makefile
|
|
(Usual test backport differences.)
|
|
|
|
diff --git a/elf/Makefile b/elf/Makefile
|
|
index 67029930dd2cb461..fc9c685b9d23bb6c 100644
|
|
--- a/elf/Makefile
|
|
+++ b/elf/Makefile
|
|
@@ -215,7 +215,7 @@ tests-internal += loadtest unload unload2 circleload1 \
|
|
tst-tls3 tst-tls6 tst-tls7 tst-tls8 tst-dlmopen2 \
|
|
tst-ptrguard1 tst-stackguard1 tst-libc_dlvsym \
|
|
tst-create_format1 tst-tls-surplus tst-dl-hwcaps_split
|
|
-tests-container += tst-pldd
|
|
+tests-container += tst-pldd tst-preload-pthread-libc
|
|
ifeq ($(build-hardcoded-path-in-tests),yes)
|
|
tests += tst-dlopen-aout
|
|
tst-dlopen-aout-no-pie = yes
|
|
diff --git a/elf/dl-deps.c b/elf/dl-deps.c
|
|
index 50f053a1586efdc3..007069f670eced95 100644
|
|
--- a/elf/dl-deps.c
|
|
+++ b/elf/dl-deps.c
|
|
@@ -610,7 +610,12 @@ Filters not supported with LD_TRACE_PRELINKING"));
|
|
memcpy (l_initfini, map->l_searchlist.r_list,
|
|
nlist * sizeof (struct link_map *));
|
|
|
|
- _dl_sort_maps (&l_initfini[1], nlist - 1, NULL, false);
|
|
+ /* If libc.so.6 is the main map, it participates in the sort, so
|
|
+ that the relocation order is correct regarding libc.so.6. */
|
|
+ if (l_initfini[0] == GL (dl_ns)[l_initfini[0]->l_ns].libc_map)
|
|
+ _dl_sort_maps (l_initfini, nlist, NULL, false);
|
|
+ else
|
|
+ _dl_sort_maps (&l_initfini[1], nlist - 1, NULL, false);
|
|
|
|
/* Terminate the list of dependencies. */
|
|
l_initfini[nlist] = NULL;
|
|
diff --git a/elf/tst-preload-pthread-libc.c b/elf/tst-preload-pthread-libc.c
|
|
new file mode 100644
|
|
index 0000000000000000..48cb512a93f3da19
|
|
--- /dev/null
|
|
+++ b/elf/tst-preload-pthread-libc.c
|
|
@@ -0,0 +1,36 @@
|
|
+/* Test relocation ordering if the main executable is libc.so.6 (bug 20972).
|
|
+ Copyright (C) 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
|
|
+ <https://www.gnu.org/licenses/>. */
|
|
+
|
|
+#include <gnu/lib-names.h>
|
|
+#include <stdio.h>
|
|
+#include <support/support.h>
|
|
+#include <unistd.h>
|
|
+
|
|
+int
|
|
+main (void)
|
|
+{
|
|
+ char *libc = xasprintf ("%s/%s", support_slibdir_prefix, LIBC_SO);
|
|
+ char *argv[] = { libc, NULL };
|
|
+ char *envp[] = { (char *) "LD_PRELOAD=" LIBPTHREAD_SO,
|
|
+ /* Relocation ordering matters most without lazy binding. */
|
|
+ (char *) "LD_BIND_NOW=1",
|
|
+ NULL };
|
|
+ execve (libc, argv, envp);
|
|
+ printf ("execve of %s failed: %m\n", libc);
|
|
+ return 1;
|
|
+}
|