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=-16.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 CFBEAC4320A for ; Fri, 30 Jul 2021 02:31:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B8A1260F5E for ; Fri, 30 Jul 2021 02:31:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235887AbhG3CbR (ORCPT ); Thu, 29 Jul 2021 22:31:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35598 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235464AbhG3CbP (ORCPT ); Thu, 29 Jul 2021 22:31:15 -0400 Received: from mail-pj1-x1036.google.com (mail-pj1-x1036.google.com [IPv6:2607:f8b0:4864:20::1036]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 93AFCC0613C1 for ; Thu, 29 Jul 2021 19:31:10 -0700 (PDT) Received: by mail-pj1-x1036.google.com with SMTP id e2-20020a17090a4a02b029016f3020d867so12294648pjh.3 for ; Thu, 29 Jul 2021 19:31:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=fUqZ0NLVZxg4yvCXyE1lEs/e7e2cakQ+3GgW8pZJCvA=; b=etYre1AjERNhjyVA/9+2+oLRj921sU45jCtD5h5fRrioHVxndRb/wVYqd+Gvs/9PWN W5TIwCrEKVrSomZp1XNcHMR3yLthFd9Qftp86Ybrvy7SLYwhXBueLu90Yc4ejQUhYSOC pE6uT73BOuVftlnSqfS6+2EzGpdU+4QF+7NHo= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=fUqZ0NLVZxg4yvCXyE1lEs/e7e2cakQ+3GgW8pZJCvA=; b=TO47HHbbJFq7EA9vTMXbv9kkgs7XXAuH7qkQgYvRgKm98s0qzS8omi0W3oHvH20GLj U2OpELz7BsskvxIoT8vSX1KMu4h3Wu4oA49jP/wEDAUcBQtPY/qUJIkrLAkYoxUou5m6 nr+bG3O02Lwd/7CDXy/EKTI2idDG0Kfv1EXJ92R0KZ01O+uSDPMLkIvNVY16QR+ago0b jlIeIX/DYGQRLpYCZQ2RTNO5z/M3/tRKCBkMV+SF9FnI1jx7ZpHuMR9wpkMPDJlkjomm PoRvvcW1P5QEjuaOk4XehbggJyEDndyjeHueDN775KhRd3e20P31HolZjOr0ZMtOIRZZ w3Tw== X-Gm-Message-State: AOAM531cGVpwT15VLvoUla5c7AT6GwqcyET5eE5oDy1qB0aHi5uKR5Pt h0BrHT9Dr6pk2oZTsdH4nipTpw== X-Google-Smtp-Source: ABdhPJxIpjyYfp2wSF3KUcMBsoeqagBGHs5J6YJ1XjDsi8DNMVFxuffmFFgkMO9ZoPoLSYu5GHbnWw== X-Received: by 2002:a05:6a00:168a:b029:2fb:6bb0:aba with SMTP id k10-20020a056a00168ab02902fb6bb00abamr526959pfc.32.1627612270101; Thu, 29 Jul 2021 19:31:10 -0700 (PDT) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id q13sm218718pjq.10.2021.07.29.19.31.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 29 Jul 2021 19:31:09 -0700 (PDT) Date: Thu, 29 Jul 2021 19:31:08 -0700 From: Kees Cook To: Bart Van Assche Cc: linux-hardening@vger.kernel.org, "Gustavo A. R. Silva" , Keith Packard , Greg Kroah-Hartman , Andrew Morton , linux-kernel@vger.kernel.org, linux-wireless@vger.kernel.org, netdev@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-staging@lists.linux.dev, linux-block@vger.kernel.org, linux-kbuild@vger.kernel.org, clang-built-linux@googlegroups.com Subject: Re: [PATCH 48/64] drbd: Use struct_group() to zero algs Message-ID: <202107291845.1E1528D@keescook> References: <20210727205855.411487-1-keescook@chromium.org> <20210727205855.411487-49-keescook@chromium.org> <1cc74e5e-8d28-6da4-244e-861eac075ca2@acm.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1cc74e5e-8d28-6da4-244e-861eac075ca2@acm.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jul 28, 2021 at 02:45:55PM -0700, Bart Van Assche wrote: > On 7/27/21 1:58 PM, Kees Cook wrote: > > In preparation for FORTIFY_SOURCE performing compile-time and run-time > > field bounds checking for memset(), avoid intentionally writing across > > neighboring fields. > > > > Add a struct_group() for the algs so that memset() can correctly reason > > about the size. > > > > Signed-off-by: Kees Cook > > --- > > drivers/block/drbd/drbd_main.c | 3 ++- > > drivers/block/drbd/drbd_protocol.h | 6 ++++-- > > drivers/block/drbd/drbd_receiver.c | 3 ++- > > 3 files changed, 8 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c > > index 55234a558e98..b824679cfcb2 100644 > > --- a/drivers/block/drbd/drbd_main.c > > +++ b/drivers/block/drbd/drbd_main.c > > @@ -729,7 +729,8 @@ int drbd_send_sync_param(struct drbd_peer_device *peer_device) > > cmd = apv >= 89 ? P_SYNC_PARAM89 : P_SYNC_PARAM; > > /* initialize verify_alg and csums_alg */ > > - memset(p->verify_alg, 0, 2 * SHARED_SECRET_MAX); > > + BUILD_BUG_ON(sizeof(p->algs) != 2 * SHARED_SECRET_MAX); > > + memset(&p->algs, 0, sizeof(p->algs)); > > if (get_ldev(peer_device->device)) { > > dc = rcu_dereference(peer_device->device->ldev->disk_conf); > > diff --git a/drivers/block/drbd/drbd_protocol.h b/drivers/block/drbd/drbd_protocol.h > > index dea59c92ecc1..a882b65ab5d2 100644 > > --- a/drivers/block/drbd/drbd_protocol.h > > +++ b/drivers/block/drbd/drbd_protocol.h > > @@ -283,8 +283,10 @@ struct p_rs_param_89 { > > struct p_rs_param_95 { > > u32 resync_rate; > > - char verify_alg[SHARED_SECRET_MAX]; > > - char csums_alg[SHARED_SECRET_MAX]; > > + struct_group(algs, > > + char verify_alg[SHARED_SECRET_MAX]; > > + char csums_alg[SHARED_SECRET_MAX]; > > + ); > > u32 c_plan_ahead; > > u32 c_delay_target; > > u32 c_fill_target; > > diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c > > index 1f740e42e457..6df2539e215b 100644 > > --- a/drivers/block/drbd/drbd_receiver.c > > +++ b/drivers/block/drbd/drbd_receiver.c > > @@ -3921,7 +3921,8 @@ static int receive_SyncParam(struct drbd_connection *connection, struct packet_i > > /* initialize verify_alg and csums_alg */ > > p = pi->data; > > - memset(p->verify_alg, 0, 2 * SHARED_SECRET_MAX); > > + BUILD_BUG_ON(sizeof(p->algs) != 2 * SHARED_SECRET_MAX); > > + memset(&p->algs, 0, sizeof(p->algs)); > > Using struct_group() introduces complexity. Has it been considered not to > modify struct p_rs_param_95 and instead to use two memset() calls instead of > one (one memset() call per member)? I went this direction because using two memset()s (or memcpy()s in other patches) changes the machine code. It's not much of a change, but it seems easier to justify "no binary changes" via the use of struct_group(). If splitting the memset() is preferred, I can totally do that instead. :) -Kees -- Kees Cook 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=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 AAA51C4320A for ; Fri, 30 Jul 2021 02:31:12 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 6CDD660F5E for ; Fri, 30 Jul 2021 02:31:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 6CDD660F5E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=chromium.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 8715F6E213; Fri, 30 Jul 2021 02:31:11 +0000 (UTC) Received: from mail-pl1-x629.google.com (mail-pl1-x629.google.com [IPv6:2607:f8b0:4864:20::629]) by gabe.freedesktop.org (Postfix) with ESMTPS id 80F1E6E213 for ; Fri, 30 Jul 2021 02:31:10 +0000 (UTC) Received: by mail-pl1-x629.google.com with SMTP id k1so9239792plt.12 for ; Thu, 29 Jul 2021 19:31:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=fUqZ0NLVZxg4yvCXyE1lEs/e7e2cakQ+3GgW8pZJCvA=; b=etYre1AjERNhjyVA/9+2+oLRj921sU45jCtD5h5fRrioHVxndRb/wVYqd+Gvs/9PWN W5TIwCrEKVrSomZp1XNcHMR3yLthFd9Qftp86Ybrvy7SLYwhXBueLu90Yc4ejQUhYSOC pE6uT73BOuVftlnSqfS6+2EzGpdU+4QF+7NHo= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=fUqZ0NLVZxg4yvCXyE1lEs/e7e2cakQ+3GgW8pZJCvA=; b=tpfT+8FMXue7gVzSzvKsIzp02bvafzx6Y79oek/VtqK9OCLtlw3Yn/p10pRy5pZtUy QmyUlW1c2gaqoUUp2B6+I7Kr6V0AkfTj7Xb9cQa+2Av1rjJjPLqA1rUeqwe3golmrCmS dVFx41lPLfnwaTrpNFQBoFtPMbs0NyyhM/8phsq2CjpT1nwbuVNds7cDshozFg98qhKR eWuVnK16eDLSW34rf20xqGN1LmhwZP5KG82w9Qqw1cmawg4Lwgf9ohpyOO8MjpF3nGPZ FDf+FKQxx4HNrG/gZhyQweYddJ31gB3i2qk8HGeGk6J2ZI/D81gVHuLe0wBp5+btj1TI vujQ== X-Gm-Message-State: AOAM532MHXM9byq+6yI56P8E92uSarbyJ6n0r1rBty9/sec6MdsBuNAh NkyQgGtEftNU00oRGaUBopTLXA== X-Google-Smtp-Source: ABdhPJxIpjyYfp2wSF3KUcMBsoeqagBGHs5J6YJ1XjDsi8DNMVFxuffmFFgkMO9ZoPoLSYu5GHbnWw== X-Received: by 2002:a05:6a00:168a:b029:2fb:6bb0:aba with SMTP id k10-20020a056a00168ab02902fb6bb00abamr526959pfc.32.1627612270101; Thu, 29 Jul 2021 19:31:10 -0700 (PDT) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id q13sm218718pjq.10.2021.07.29.19.31.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 29 Jul 2021 19:31:09 -0700 (PDT) Date: Thu, 29 Jul 2021 19:31:08 -0700 From: Kees Cook To: Bart Van Assche Subject: Re: [PATCH 48/64] drbd: Use struct_group() to zero algs Message-ID: <202107291845.1E1528D@keescook> References: <20210727205855.411487-1-keescook@chromium.org> <20210727205855.411487-49-keescook@chromium.org> <1cc74e5e-8d28-6da4-244e-861eac075ca2@acm.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1cc74e5e-8d28-6da4-244e-861eac075ca2@acm.org> X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-kbuild@vger.kernel.org, Greg Kroah-Hartman , linux-staging@lists.linux.dev, linux-wireless@vger.kernel.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, "Gustavo A. R. Silva" , linux-block@vger.kernel.org, clang-built-linux@googlegroups.com, Keith Packard , linux-hardening@vger.kernel.org, netdev@vger.kernel.org, Andrew Morton Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Wed, Jul 28, 2021 at 02:45:55PM -0700, Bart Van Assche wrote: > On 7/27/21 1:58 PM, Kees Cook wrote: > > In preparation for FORTIFY_SOURCE performing compile-time and run-time > > field bounds checking for memset(), avoid intentionally writing across > > neighboring fields. > > > > Add a struct_group() for the algs so that memset() can correctly reason > > about the size. > > > > Signed-off-by: Kees Cook > > --- > > drivers/block/drbd/drbd_main.c | 3 ++- > > drivers/block/drbd/drbd_protocol.h | 6 ++++-- > > drivers/block/drbd/drbd_receiver.c | 3 ++- > > 3 files changed, 8 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c > > index 55234a558e98..b824679cfcb2 100644 > > --- a/drivers/block/drbd/drbd_main.c > > +++ b/drivers/block/drbd/drbd_main.c > > @@ -729,7 +729,8 @@ int drbd_send_sync_param(struct drbd_peer_device *peer_device) > > cmd = apv >= 89 ? P_SYNC_PARAM89 : P_SYNC_PARAM; > > /* initialize verify_alg and csums_alg */ > > - memset(p->verify_alg, 0, 2 * SHARED_SECRET_MAX); > > + BUILD_BUG_ON(sizeof(p->algs) != 2 * SHARED_SECRET_MAX); > > + memset(&p->algs, 0, sizeof(p->algs)); > > if (get_ldev(peer_device->device)) { > > dc = rcu_dereference(peer_device->device->ldev->disk_conf); > > diff --git a/drivers/block/drbd/drbd_protocol.h b/drivers/block/drbd/drbd_protocol.h > > index dea59c92ecc1..a882b65ab5d2 100644 > > --- a/drivers/block/drbd/drbd_protocol.h > > +++ b/drivers/block/drbd/drbd_protocol.h > > @@ -283,8 +283,10 @@ struct p_rs_param_89 { > > struct p_rs_param_95 { > > u32 resync_rate; > > - char verify_alg[SHARED_SECRET_MAX]; > > - char csums_alg[SHARED_SECRET_MAX]; > > + struct_group(algs, > > + char verify_alg[SHARED_SECRET_MAX]; > > + char csums_alg[SHARED_SECRET_MAX]; > > + ); > > u32 c_plan_ahead; > > u32 c_delay_target; > > u32 c_fill_target; > > diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c > > index 1f740e42e457..6df2539e215b 100644 > > --- a/drivers/block/drbd/drbd_receiver.c > > +++ b/drivers/block/drbd/drbd_receiver.c > > @@ -3921,7 +3921,8 @@ static int receive_SyncParam(struct drbd_connection *connection, struct packet_i > > /* initialize verify_alg and csums_alg */ > > p = pi->data; > > - memset(p->verify_alg, 0, 2 * SHARED_SECRET_MAX); > > + BUILD_BUG_ON(sizeof(p->algs) != 2 * SHARED_SECRET_MAX); > > + memset(&p->algs, 0, sizeof(p->algs)); > > Using struct_group() introduces complexity. Has it been considered not to > modify struct p_rs_param_95 and instead to use two memset() calls instead of > one (one memset() call per member)? I went this direction because using two memset()s (or memcpy()s in other patches) changes the machine code. It's not much of a change, but it seems easier to justify "no binary changes" via the use of struct_group(). If splitting the memset() is preferred, I can totally do that instead. :) -Kees -- Kees Cook