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authorAl Viro <viro@ZenIV.linux.org.uk>2016-09-15 02:35:29 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-09-24 10:07:43 +0200
commit9d25c78ec01c402dc56272693c44ef9d72ecdd2e (patch)
tree17dea7497eb8d50ae4a7974daac737daee6c474c
parenta14f64ca402125152197f14783d97bc1a1e8279f (diff)
fix minor infoleak in get_user_ex()
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 <viro@zeniv.linux.org.uk> [ This sat in different branch from the uaccess fixes since mid-August ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--arch/x86/include/asm/uaccess.h6
1 files changed, 5 insertions, 1 deletions
diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
index 09b1b0ab94b7..d42252ce9b4d 100644
--- 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) \