Avoid backtrace from __stack_chk_fail [BZ #12189]

__stack_chk_fail is called on corrupted stack.  Stack backtrace is very
unreliable against corrupted stack.  __libc_message is changed to accept
enum __libc_message_action and call BEFORE_ABORT only if action includes
do_backtrace.  __fortify_fail_abort is added to avoid backtrace from
__stack_chk_fail.

	[BZ #12189]
	* debug/Makefile (CFLAGS-tst-ssp-1.c): New.
	(tests): Add tst-ssp-1 if -fstack-protector works.
	* debug/fortify_fail.c: Include <stdbool.h>.
	(_fortify_fail_abort): New function.
	(__fortify_fail): Call _fortify_fail_abort.
	(__fortify_fail_abort): Add a hidden definition.
	* debug/stack_chk_fail.c: Include <stdbool.h>.
	(__stack_chk_fail): Call __fortify_fail_abort, instead of
	__fortify_fail.
	* debug/tst-ssp-1.c: New file.
	* include/stdio.h (__libc_message_action): New enum.
	(__libc_message): Replace int with enum __libc_message_action.
	(__fortify_fail_abort): New hidden prototype.
	* malloc/malloc.c (malloc_printerr): Update __libc_message calls.
	* sysdeps/posix/libc_fatal.c (__libc_message): Replace int
	with enum __libc_message_action.  Call BEFORE_ABORT only if
	action includes do_backtrace.
	(__libc_fatal): Update __libc_message call.

1 files changed, 45 insertions, 0 deletions

diff --git a/debug/tst-ssp-1.c b/debug/tst-ssp-1.c
new file mode 100644
index 0000000..52c67e2
--- /dev/null
+++ b/debug/tst-ssp-1.c
@@ -0,0 +1,45 @@
+/* Verify that __stack_chk_fail won't segfault.
+   Copyright (C) 2017 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
+   <http://www.gnu.org/licenses/>.  */
+
+/* Based on gcc.dg/ssp-1.c from GCC testsuite.  */
+
+#include <signal.h>
+
+static void
+__attribute__ ((noinline, noclone))
+test (char *foo)
+{
+  int i;
+
+  /* smash stack */
+  for (i = 0; i <= 400; i++)
+    foo[i] = 42;
+}
+
+static int
+do_test (void)
+{
+  char foo[30];
+
+  test (foo);
+
+  return 1; /* fail */
+}
+
+#define EXPECTED_SIGNAL SIGABRT
+#include <support/test-driver.c>