From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CE9E4C06510 for ; Tue, 2 Jul 2019 00:25:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9A7E62173E for ; Tue, 2 Jul 2019 00:25:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1562027126; bh=MPIDSjZSqrqTeWvWT//E/0wZy5fEnuIgGI95YyoSxss=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=MzP7/Y/7c+URI6yaHenhSgg8QNEZqtZirPQS4mRD0Bd7mZcYMNKr6/DZNGliI1jNi yhvnLc0UmlrJ/L86BhU+9gxwl8MIPRhFz+/oV9m0Jo1Q0uO8hdKa9p/i5zSNfOlFam UTTRhJto2+EtHwejftEcW42wQJq6Hdtg4nGtOhdE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727073AbfGBAZZ (ORCPT ); Mon, 1 Jul 2019 20:25:25 -0400 Received: from mail.kernel.org ([198.145.29.99]:40162 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727023AbfGBAZY (ORCPT ); Mon, 1 Jul 2019 20:25:24 -0400 Received: from sol.localdomain (c-24-5-143-220.hsd1.ca.comcast.net [24.5.143.220]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 9319C21721; Tue, 2 Jul 2019 00:25:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1562027123; bh=MPIDSjZSqrqTeWvWT//E/0wZy5fEnuIgGI95YyoSxss=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=K17hf1xlfaVcjMn/oGAGN5LYYVhtG4iXNAAmaxiEg6SyeDPInPxpVPw9wjAXFJ5Yg T+yiH8itPf3deW5gsoP+7cb8s7Psg8LUbHUvGwIGZ6WFZTbzcNOAvJrUISTps6zu/7 S2f7kL+yDqHTPQbr/5Lua9vshmIaF/SqxhPY5dYg= Date: Mon, 1 Jul 2019 17:25:22 -0700 From: Eric Biggers To: Cfir Cohen Cc: Tom Lendacky , Gary Hook , Herbert Xu , David Rientjes , linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org Subject: Re: [PATCH] crypto: ccp/gcm - use const time tag comparison. Message-ID: <20190702002522.GA693@sol.localdomain> References: <20190702000132.88836-1-cfir@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190702000132.88836-1-cfir@google.com> User-Agent: Mutt/1.12.1 (2019-06-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jul 01, 2019 at 05:01:32PM -0700, Cfir Cohen wrote: > Avoid leaking GCM tag through timing side channel. > > Signed-off-by: Cfir Cohen > --- > drivers/crypto/ccp/ccp-ops.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/crypto/ccp/ccp-ops.c b/drivers/crypto/ccp/ccp-ops.c > index db8de89d990f..633670220f6c 100644 > --- a/drivers/crypto/ccp/ccp-ops.c > +++ b/drivers/crypto/ccp/ccp-ops.c > @@ -840,7 +840,8 @@ static int ccp_run_aes_gcm_cmd(struct ccp_cmd_queue *cmd_q, > if (ret) > goto e_tag; > > - ret = memcmp(tag.address, final_wa.address, AES_BLOCK_SIZE); > + ret = crypto_memneq(tag.address, final_wa.address, > + AES_BLOCK_SIZE) ? -EBADMSG : 0; > ccp_dm_free(&tag); > } > > -- > 2.22.0.410.gd8fdbe21b5-goog > Looks like this needs: Fixes: 36cf515b9bbe ("crypto: ccp - Enable support for AES GCM on v5 CCPs") Cc: # v4.12+ - Eric