From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751121AbcBLHMA (ORCPT ); Fri, 12 Feb 2016 02:12:00 -0500 Received: from tundra.namei.org ([65.99.196.166]:38326 "EHLO namei.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750714AbcBLHL6 (ORCPT ); Fri, 12 Feb 2016 02:11:58 -0500 Date: Fri, 12 Feb 2016 18:11:54 +1100 (AEDT) From: James Morris To: Linus Torvalds cc: linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [GIT] EVM hmac security fix Message-ID: User-Agent: Alpine 2.20 (LRH 67 2015-01-07) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Please pull this patch for the EVM code, which fixes CVE-2016-2085. The following changes since commit c05235d50f681bf685e7290cae05ab3b4fa493f3: Merge tag 'gpio-v4.5-2' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio (2016-02-11 11:25:55 -0800) are available in the git repository at: git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security.git for-linus Ryan Ware (1): EVM: Use crypto_memneq() for digest comparisons security/integrity/evm/evm_main.c | 3 ++- 1 files changed, 2 insertions(+), 1 deletions(-) --- commit 613317bd212c585c20796c10afe5daaa95d4b0a1 Author: Ryan Ware Date: Thu Feb 11 15:58:44 2016 -0800 EVM: Use crypto_memneq() for digest comparisons 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 Signed-off-by: Ryan Ware Cc: stable@vger.kernel.org Signed-off-by: Mimi Zohar Signed-off-by: James Morris diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c index f716025..e6ea9d4 100644 --- a/security/integrity/evm/evm_main.c +++ b/security/integrity/evm/evm_main.c @@ -23,6 +23,7 @@ #include #include #include +#include #include "evm.h" int evm_initialized; @@ -148,7 +149,7 @@ static enum integrity_status evm_verify_hmac(struct dentry *dentry, 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;