Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751877AbdFJC7j (ORCPT ); Fri, 9 Jun 2017 22:59:39 -0400 Received: from frisell.zx2c4.com ([192.95.5.64]:52679 "EHLO frisell.zx2c4.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751859AbdFJC7g (ORCPT ); Fri, 9 Jun 2017 22:59:36 -0400 From: "Jason A. Donenfeld" To: linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com Cc: "Jason A. Donenfeld" , David Safford , Mimi Zohar , David Howells , keyrings@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH 4/6] security/keys: use constant time memory comparison for macs Date: Sat, 10 Jun 2017 04:59:10 +0200 Message-Id: <20170610025912.6499-5-Jason@zx2c4.com> In-Reply-To: <20170610025912.6499-1-Jason@zx2c4.com> References: <20170610025912.6499-1-Jason@zx2c4.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1609 Lines: 53 Otherwise, we enable a MAC forgery via timing attack. Signed-off-by: Jason A. Donenfeld Cc: David Safford Cc: Mimi Zohar Cc: David Howells Cc: keyrings@vger.kernel.org Cc: stable@vger.kernel.org --- security/keys/trusted.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/security/keys/trusted.c b/security/keys/trusted.c index 2ae31c5a87de..df7d30b0a6f7 100644 --- a/security/keys/trusted.c +++ b/security/keys/trusted.c @@ -11,6 +11,7 @@ * See Documentation/security/keys-trusted-encrypted.txt */ +#include #include #include #include @@ -243,7 +244,7 @@ static int TSS_checkhmac1(unsigned char *buffer, if (ret < 0) goto out; - if (memcmp(testhmac, authdata, SHA1_DIGEST_SIZE)) + if (crypto_memneq(testhmac, authdata, SHA1_DIGEST_SIZE)) ret = -EINVAL; out: kfree(sdesc); @@ -335,7 +336,7 @@ static int TSS_checkhmac2(unsigned char *buffer, TPM_NONCE_SIZE, ononce, 1, continueflag1, 0, 0); if (ret < 0) goto out; - if (memcmp(testhmac1, authdata1, SHA1_DIGEST_SIZE)) { + if (crypto_memneq(testhmac1, authdata1, SHA1_DIGEST_SIZE)) { ret = -EINVAL; goto out; } @@ -344,7 +345,7 @@ static int TSS_checkhmac2(unsigned char *buffer, TPM_NONCE_SIZE, ononce, 1, continueflag2, 0, 0); if (ret < 0) goto out; - if (memcmp(testhmac2, authdata2, SHA1_DIGEST_SIZE)) + if (crypto_memneq(testhmac2, authdata2, SHA1_DIGEST_SIZE)) ret = -EINVAL; out: kfree(sdesc); -- 2.13.1