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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 31B09C433F5 for ; Fri, 6 May 2022 10:01:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1390772AbiEFKFG (ORCPT ); Fri, 6 May 2022 06:05:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47518 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1358846AbiEFKFF (ORCPT ); Fri, 6 May 2022 06:05:05 -0400 Received: from mga18.intel.com (mga18.intel.com [134.134.136.126]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6BA155A2D5; Fri, 6 May 2022 03:01:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1651831283; x=1683367283; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=v9a6QaqxlteklQ5eDNhQA4DeU/Xa34oGSnLKTwJy6DU=; b=JUVhfrYo5ayOFHdgpYwlnxBWbTIoF4PTT117/zFkqtE8Bh7DpO4qRexL t5GhcW0zsUyVYbYs58yB7FRgnbw+BKjLcBV+rVDrVSAXs5SbKxiOIl9Mm C5K4aOBS/zBwT4PiJeoYy6jTOVLrn8GIvAzuo1iEqF6yWDrldPWwWlYcE kVGl8IixDQkybWYY/UXNB8UgJxfzCUQdg8K8NWx+70o7nVNHact5jt3DQ R8IkTyHyMPRT2Kv75mU9i27GRHbSces+Fbt+a8GIwno1K9COg02haTH07 8Q8EeLbF6NMKxaMWnDErw8gPjgbhvSVpRiTVDnqpMImB7YJUmcmjE3pMW w==; X-IronPort-AV: E=McAfee;i="6400,9594,10338"; a="250420256" X-IronPort-AV: E=Sophos;i="5.91,203,1647327600"; d="scan'208";a="250420256" Received: from orsmga004.jf.intel.com ([10.7.209.38]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 May 2022 03:01:22 -0700 X-IronPort-AV: E=Sophos;i="5.91,203,1647327600"; d="scan'208";a="695107850" Received: from silpixa00400314.ir.intel.com (HELO silpixa00400314) ([10.237.222.76]) by orsmga004-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 May 2022 03:01:20 -0700 Date: Fri, 6 May 2022 11:01:17 +0100 From: Giovanni Cabiddu To: Greg KH Cc: herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org, qat-linux@intel.com, vdronov@redhat.com, stable@vger.kernel.org, Adam Guerin , Wojciech Ziemba Subject: Re: [PATCH 07/12] crypto: qat - set to zero DH parameters before free Message-ID: References: <20220506082327.21605-1-giovanni.cabiddu@intel.com> <20220506082327.21605-8-giovanni.cabiddu@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Organization: Intel Research and Development Ireland Ltd - Co. Reg. #308263 - Collinstown Industrial Park, Leixlip, County Kildare - Ireland Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Fri, May 06, 2022 at 11:23:50AM +0200, Greg KH wrote: > On Fri, May 06, 2022 at 09:23:22AM +0100, Giovanni Cabiddu wrote: > > Set to zero the DH context buffers containing the DH key before they are > > freed. > > That says what, but not why. > > > Cc: stable@vger.kernel.org > > Fixes: c9839143ebbf ("crypto: qat - Add DH support") > > Signed-off-by: Giovanni Cabiddu > > Reviewed-by: Adam Guerin > > Reviewed-by: Wojciech Ziemba > > --- > > drivers/crypto/qat/qat_common/qat_asym_algs.c | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/drivers/crypto/qat/qat_common/qat_asym_algs.c b/drivers/crypto/qat/qat_common/qat_asym_algs.c > > index d75eb77c9fb9..2fec89b8a188 100644 > > --- a/drivers/crypto/qat/qat_common/qat_asym_algs.c > > +++ b/drivers/crypto/qat/qat_common/qat_asym_algs.c > > @@ -421,14 +421,17 @@ static int qat_dh_set_params(struct qat_dh_ctx *ctx, struct dh *params) > > static void qat_dh_clear_ctx(struct device *dev, struct qat_dh_ctx *ctx) > > { > > if (ctx->g) { > > + memzero_explicit(ctx->g, ctx->p_size); > > dma_free_coherent(dev, ctx->p_size, ctx->g, ctx->dma_g); > > Why is a memset() not sufficient here? Based on the previous conversation a memset() should be sufficient. > And what is this solving? Who would get this stale data? This is to make sure the buffer containing sensitive data (i.e. a key) is not leaked out by a subsequent allocation. I will clarify it in the commit message. Thanks, -- Giovanni