Patch "EVM: Use crypto_memneq() for digest comparisons" has been added to the 4.3-stable tree

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 <[email protected]> know about it.

From: Ryan Ware <[email protected]>
Date: Thu, 11 Feb 2016 15:58:44 -0800
Subject: EVM: Use crypto_memneq() for digest comparisons

From: Ryan Ware <[email protected]>

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().

---
 security/integrity/evm/evm_main.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

@@ -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 [email protected] are

queue-4.3/evm-use-crypto_memneq-for-digest-comparisons.patch