4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Al Viro <v...@zeniv.linux.org.uk>
commit 1c109fabbd51863475cd12ac206bdd249aee35af upstream.
get_user_ex(x, ptr) should zero x on failure. It's not a lot of a leak
(at most we are leaking uninitialized 64bit value off the kernel stack,
and in a fairly constrained situation, at that), but the fix is trivial,
so...
Signed-off-by: Al Viro <v...@zeniv.linux.org.uk>
[ This sat in different branch from the uaccess fixes since mid-August ]
Signed-off-by: Linus Torvalds <torva...@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
arch/x86/include/asm/uaccess.h | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
--- a/arch/x86/include/asm/uaccess.h
+++ b/arch/x86/include/asm/uaccess.h
@@ -394,7 +394,11 @@ do {
\
#define __get_user_asm_ex(x, addr, itype, rtype, ltype)
\
asm volatile("1: mov"itype" %1,%"rtype"0\n" \
"2:\n" \
- _ASM_EXTABLE_EX(1b, 2b) \
+ ".section .fixup,\"ax\"\n" \
+ "3:xor"itype" %"rtype"0,%"rtype"0\n" \
+ " jmp 2b\n" \
+ ".previous\n" \
+ _ASM_EXTABLE_EX(1b, 3b) \
: ltype(x) : "m" (__m(addr)))
#define __put_user_nocheck(x, ptr, size) \
