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authorH.J. Lu <hjl.tools@gmail.com>2017-07-24 06:06:08 -0700
committerH.J. Lu <hjl.tools@gmail.com>2017-07-24 06:06:24 -0700
commit422ff87c249ddc06701d096421db63343e4754be (patch)
treee095970d350bffebdd21f9fa75a24494aeebbc47 /debug
parent55703fcace89b53d7f41f7d85ede50571da2bcc8 (diff)
downloadglibc-422ff87c249ddc06701d096421db63343e4754be.tar.gz
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Avoid accessing corrupted stack from __stack_chk_fail [BZ #21752]
__libc_argv[0] points to address on stack and __libc_secure_getenv
accesses environment variables which are on stack.  We should avoid
accessing stack when stack is corrupted.

This patch also renames function argument in __fortify_fail_abort
from do_backtrace to need_backtrace to avoid confusion with do_backtrace
from enum __libc_message_action.

	[BZ #21752]
	* debug/fortify_fail.c (__fortify_fail_abort): Don't pass down
	__libc_argv[0] if we aren't doing backtrace.  Rename do_backtrace
	to need_backtrace.
	* sysdeps/posix/libc_fatal.c (__libc_message): Don't call
	__libc_secure_getenv if we aren't doing backtrace.
Diffstat (limited to 'debug')
-rw-r--r--debug/fortify_fail.c12
1 files changed, 8 insertions, 4 deletions
diff --git a/debug/fortify_fail.c b/debug/fortify_fail.c
index c90d384daf..a0777ae570 100644
--- a/debug/fortify_fail.c
+++ b/debug/fortify_fail.c
@@ -24,13 +24,17 @@ extern char **__libc_argv attribute_hidden;
 
 void
 __attribute__ ((noreturn)) internal_function
-__fortify_fail_abort (_Bool do_backtrace, const char *msg)
+__fortify_fail_abort (_Bool need_backtrace, const char *msg)
 {
-  /* The loop is added only to keep gcc happy.  */
+  /* The loop is added only to keep gcc happy.  Don't pass down
+     __libc_argv[0] if we aren't doing backtrace since __libc_argv[0]
+     may point to the corrupted stack.  */
   while (1)
-    __libc_message (do_backtrace ? (do_abort | do_backtrace) : do_abort,
+    __libc_message (need_backtrace ? (do_abort | do_backtrace) : do_abort,
 		    "*** %s ***: %s terminated\n",
-		    msg, __libc_argv[0] ?: "<unknown>");
+		    msg,
+		    (need_backtrace && __libc_argv[0] != NULL
+		     ? __libc_argv[0] : "<unknown>"));
 }
 
 void