This is a note to let you know that I've just added the patch titled
EVM: Use crypto_memneq() for digest comparisons
to the 4.3-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
evm-use-crypto_memneq-for-digest-comparisons.patch
and it can be found in the queue-4.3 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 613317bd212c585c20796c10afe5daaa95d4b0a1 Mon Sep 17 00:00:00 2001
From: Ryan Ware <ware@xxxxxxxxxxxxxxx>
Date: Thu, 11 Feb 2016 15:58:44 -0800
Subject: EVM: Use crypto_memneq() for digest comparisons
From: Ryan Ware <ware@xxxxxxxxxxxxxxx>
commit 613317bd212c585c20796c10afe5daaa95d4b0a1 upstream.
This patch fixes vulnerability CVE-2016-2085. The problem exists
because the vm_verify_hmac() function includes a use of memcmp().
Unfortunately, this allows timing side channel attacks; specifically
a MAC forgery complexity drop from 2^128 to 2^12. This patch changes
the memcmp() to the cryptographically safe crypto_memneq().
Reported-by: Xiaofei Rex Guo <xiaofei.rex.guo@xxxxxxxxx>
Signed-off-by: Ryan Ware <ware@xxxxxxxxxxxxxxx>
Signed-off-by: Mimi Zohar <zohar@xxxxxxxxxxxxxxxxxx>
Signed-off-by: James Morris <james.l.morris@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
security/integrity/evm/evm_main.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/security/integrity/evm/evm_main.c
+++ b/security/integrity/evm/evm_main.c
@@ -23,6 +23,7 @@
#include <linux/integrity.h>
#include <linux/evm.h>
#include <crypto/hash.h>
+#include <crypto/algapi.h>
#include "evm.h"
int evm_initialized;
@@ -148,7 +149,7 @@ static enum integrity_status evm_verify_
xattr_value_len, calc.digest);
if (rc)
break;
- rc = memcmp(xattr_data->digest, calc.digest,
+ rc = crypto_memneq(xattr_data->digest, calc.digest,
sizeof(calc.digest));
if (rc)
rc = -EINVAL;
Patches currently in stable-queue which might be from ware@xxxxxxxxxxxxxxx are
queue-4.3/evm-use-crypto_memneq-for-digest-comparisons.patch
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