Check for valid stack frame in longjmp.

If longjmp restores the stack frame to an address which is beyond
the stack frame at the time of the longjmp call it would install
an uninitialized stack frame.  If compiled with _FORTIFY_SOURCE
defined, longjmp will now bail out in this situation.

1 files changed, 28 insertions, 0 deletions

diff --git a/debug/longjmp_chk.c b/debug/longjmp_chk.c
new file mode 100644
index 0000000..7de2a98
--- /dev/null
+++ b/debug/longjmp_chk.c
@@ -0,0 +1,28 @@
+/* Copyright (C) 2009 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, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <setjmp.h>
+
+// XXX Should move to include/setjmp.h
+extern void ____longjmp_chk (__jmp_buf __env, int __val)
+     __attribute__ ((__noreturn__));
+
+#define __longjmp ____longjmp_chk
+#define __libc_siglongjmp __longjmp_chk
+
+#include <setjmp/longjmp.c>