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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id m6sm4511294pfc.151.2021.07.27.14.16.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 27 Jul 2021 14:16:50 -0700 (PDT) From: Kees Cook To: linux-hardening@vger.kernel.org Cc: Kees Cook , "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: [PATCH 62/64] netlink: Avoid false-positive memcpy() warning Date: Tue, 27 Jul 2021 13:58:53 -0700 Message-Id: <20210727205855.411487-63-keescook@chromium.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210727205855.411487-1-keescook@chromium.org> References: <20210727205855.411487-1-keescook@chromium.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1678; h=from:subject; bh=vs/nNFIrJxwpI5nY+xgEPX6hqzmriBWLvM3b/eZbMbo=; b=owEBbQKS/ZANAwAKAYly9N/cbcAmAcsmYgBhAHOOsotWr+xLgDAagynSwACfihlJOnm7qN9/Mu92 bGzCtbGJAjMEAAEKAB0WIQSlw/aPIp3WD3I+bhOJcvTf3G3AJgUCYQBzjgAKCRCJcvTf3G3AJj/ZD/ 9ntjJhpq8fBwkjGH+dUg05xTxsNzIOuiH2+WA92AhYmbos7FaDGTm1g+GjbS9tYtH4WO2HSlLQe7LQ FBHmUbu6aiUm0Adb7gUZE3muL85N91x3mnnmxIoo2J/A/2tV0zkQyLUOckCj8VK+SR9BfW61OwCULU 7dXUvxZG2bCfldSz9FFpeTg6B3n38v7ZsFzE0Z+OKqNG5B6gy6nq9hQDiK5eWY7jsHwu6TaCX2KdWP ox3h/ObmvzejD4r5bqMjjhvU16eLjApW1M3mdaJGfxBeiC7Hn4U7R0R/a57zPmDRTbz/MhdWbOOFDp ABNXWuprZfW5V1fn74AOyo4Qdi0fWAhH4ttZZuPFnGp39cUNy/oe1zMgHhD+XjhBS0RMucpc7gNElk gk4SaMhbgnC4Ou6wBhA+yQfDvMUjqtRWUuRYmsFZ5Llmrlr/jWnsbjlt39vSdTBC9vTKSqnxgt1omQ fQi/9qcta+kyf71Lx1H+c1m8ve+vz4yBPxEJ5ztsLmSYk+J3LMojiNObOTsmlTFbCj4ZoDBFSpnQga mYRnTFbLCAQHQtPXM2pa7+qmWPgSz70szWlbF1IDWFBmyv8JppWdlZQu+0ThYGXTdnhi+QLNwm/WxH Zw293JAH5hVEyNiT/+/fkkV4VjclpW+bzGJvvMPBwvfpxzJKDGLjwSx2fyMw== X-Developer-Key: i=keescook@chromium.org; a=openpgp; fpr=A5C3F68F229DD60F723E6E138972F4DFDC6DC026 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In preparation for FORTIFY_SOURCE performing compile-time and run-time field bounds checking for memcpy(), memmove(), and memset(), avoid intentionally writing across neighboring fields. Add a flexible array member to mark the end of struct nlmsghdr, and split the memcpy() to avoid false positive memcpy() warning: memcpy: detected field-spanning write (size 32) of single field (size 16) Signed-off-by: Kees Cook --- include/uapi/linux/netlink.h | 1 + net/netlink/af_netlink.c | 4 +++- 2 files changed, 4 insertions(+), 1 deletion(-) diff --git a/include/uapi/linux/netlink.h b/include/uapi/linux/netlink.h index 4c0cde075c27..ddeaa748df5e 100644 --- a/include/uapi/linux/netlink.h +++ b/include/uapi/linux/netlink.h @@ -47,6 +47,7 @@ struct nlmsghdr { __u16 nlmsg_flags; /* Additional flags */ __u32 nlmsg_seq; /* Sequence number */ __u32 nlmsg_pid; /* Sending process port ID */ + __u8 contents[]; }; /* Flags values */ diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index 24b7cf447bc5..f2dd99e96822 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -2447,7 +2447,9 @@ void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err, NLMSG_ERROR, payload, flags); errmsg = nlmsg_data(rep); errmsg->error = err; - memcpy(&errmsg->msg, nlh, payload > sizeof(*errmsg) ? nlh->nlmsg_len : sizeof(*nlh)); + memcpy(&errmsg->msg, nlh, sizeof(*nlh)); + if (payload > sizeof(*errmsg)) + memcpy(errmsg->msg.contents, nlh->contents, nlh->nlmsg_len - sizeof(*nlh)); if (nlk_has_extack && extack) { if (extack->_msg) { -- 2.30.2 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,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 81BCEC19F31 for ; Tue, 27 Jul 2021 21:17:05 +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 230F360F9C for ; Tue, 27 Jul 2021 21:17:05 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 230F360F9C 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 1D4E16EA9E; Tue, 27 Jul 2021 21:17:00 +0000 (UTC) Received: from mail-pj1-x1030.google.com (mail-pj1-x1030.google.com [IPv6:2607:f8b0:4864:20::1030]) by gabe.freedesktop.org (Postfix) with ESMTPS id 0088F6E9EF for ; Tue, 27 Jul 2021 21:16:53 +0000 (UTC) Received: by mail-pj1-x1030.google.com with SMTP id e2-20020a17090a4a02b029016f3020d867so1115219pjh.3 for ; Tue, 27 Jul 2021 14:16:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=HP4OyANmlGcmztFWqw/dgo2DQckUAHhybqKwZBENvis=; b=LCA95eGQPuDryGp7EbL19tEBN1vZX/DV2Ru999TrrBIWyGTxCgkLiQwMnWVaK3dqpk 60QOsc5jmDPjJIsota7QsQXAPPxE36dJdfR+Ydl1pbfvgmM6HMxLTyilm0vGV2trPRqk qPStf78RsWs4Jdx6SvJZesYZLDr/2M1lshLlo= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=HP4OyANmlGcmztFWqw/dgo2DQckUAHhybqKwZBENvis=; b=Fl9j0w4fBrsGCWjhmZRTqUjaXlC27rsG2kQSVG1je5sP/rNgMkxoCLdoodA0ToHLLg mz7U5x272fKS1BeMbvhgf4IaI6skBxno80PVGbtWUnsyV/ehNB+3AOr9FSUyNH9mWPCm 14IsL4L0eGZyLbyyR3ZrZskf2E1vKLu5YwZNKw/WOueS/Z2AYBOJSso5MYLx4pIJndRW 08bLA78HrkyekefrTTpbjhJ8BCryM220BFKWMMjVDkzBbTbcwajK7Aqw18NULALHfg+G gmdjdkbzZb4ejpUjcvV91w0QuEGHKYTQnOruwZPtSNu4jQHpdSN+JOxNH4IATFLx13p2 +C2Q== X-Gm-Message-State: AOAM531UG3EsF2lrzep+23Qp8ruG26Sav0NxUI5Yo0Biv6EcUY6EYrgA gnQ7o7jphPOJZ6l7Yd3KPMqalQ== X-Google-Smtp-Source: ABdhPJxnDJcYqdBzy28fe0pM7iN+zbksS85dJ1SqWH/meLyEzdRT3xN+44Z+ArcWYMJYdepJ2zZ1uQ== X-Received: by 2002:a17:90a:c902:: with SMTP id v2mr6116581pjt.136.1627420613728; Tue, 27 Jul 2021 14:16:53 -0700 (PDT) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id m6sm4511294pfc.151.2021.07.27.14.16.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 27 Jul 2021 14:16:50 -0700 (PDT) From: Kees Cook To: linux-hardening@vger.kernel.org Subject: [PATCH 62/64] netlink: Avoid false-positive memcpy() warning Date: Tue, 27 Jul 2021 13:58:53 -0700 Message-Id: <20210727205855.411487-63-keescook@chromium.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210727205855.411487-1-keescook@chromium.org> References: <20210727205855.411487-1-keescook@chromium.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1678; h=from:subject; bh=vs/nNFIrJxwpI5nY+xgEPX6hqzmriBWLvM3b/eZbMbo=; b=owEBbQKS/ZANAwAKAYly9N/cbcAmAcsmYgBhAHOOsotWr+xLgDAagynSwACfihlJOnm7qN9/Mu92 bGzCtbGJAjMEAAEKAB0WIQSlw/aPIp3WD3I+bhOJcvTf3G3AJgUCYQBzjgAKCRCJcvTf3G3AJj/ZD/ 9ntjJhpq8fBwkjGH+dUg05xTxsNzIOuiH2+WA92AhYmbos7FaDGTm1g+GjbS9tYtH4WO2HSlLQe7LQ FBHmUbu6aiUm0Adb7gUZE3muL85N91x3mnnmxIoo2J/A/2tV0zkQyLUOckCj8VK+SR9BfW61OwCULU 7dXUvxZG2bCfldSz9FFpeTg6B3n38v7ZsFzE0Z+OKqNG5B6gy6nq9hQDiK5eWY7jsHwu6TaCX2KdWP ox3h/ObmvzejD4r5bqMjjhvU16eLjApW1M3mdaJGfxBeiC7Hn4U7R0R/a57zPmDRTbz/MhdWbOOFDp ABNXWuprZfW5V1fn74AOyo4Qdi0fWAhH4ttZZuPFnGp39cUNy/oe1zMgHhD+XjhBS0RMucpc7gNElk gk4SaMhbgnC4Ou6wBhA+yQfDvMUjqtRWUuRYmsFZ5Llmrlr/jWnsbjlt39vSdTBC9vTKSqnxgt1omQ fQi/9qcta+kyf71Lx1H+c1m8ve+vz4yBPxEJ5ztsLmSYk+J3LMojiNObOTsmlTFbCj4ZoDBFSpnQga mYRnTFbLCAQHQtPXM2pa7+qmWPgSz70szWlbF1IDWFBmyv8JppWdlZQu+0ThYGXTdnhi+QLNwm/WxH Zw293JAH5hVEyNiT/+/fkkV4VjclpW+bzGJvvMPBwvfpxzJKDGLjwSx2fyMw== X-Developer-Key: i=keescook@chromium.org; a=openpgp; fpr=A5C3F68F229DD60F723E6E138972F4DFDC6DC026 Content-Transfer-Encoding: 8bit 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: Kees Cook , 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 , netdev@vger.kernel.org, Andrew Morton Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" In preparation for FORTIFY_SOURCE performing compile-time and run-time field bounds checking for memcpy(), memmove(), and memset(), avoid intentionally writing across neighboring fields. Add a flexible array member to mark the end of struct nlmsghdr, and split the memcpy() to avoid false positive memcpy() warning: memcpy: detected field-spanning write (size 32) of single field (size 16) Signed-off-by: Kees Cook --- include/uapi/linux/netlink.h | 1 + net/netlink/af_netlink.c | 4 +++- 2 files changed, 4 insertions(+), 1 deletion(-) diff --git a/include/uapi/linux/netlink.h b/include/uapi/linux/netlink.h index 4c0cde075c27..ddeaa748df5e 100644 --- a/include/uapi/linux/netlink.h +++ b/include/uapi/linux/netlink.h @@ -47,6 +47,7 @@ struct nlmsghdr { __u16 nlmsg_flags; /* Additional flags */ __u32 nlmsg_seq; /* Sequence number */ __u32 nlmsg_pid; /* Sending process port ID */ + __u8 contents[]; }; /* Flags values */ diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index 24b7cf447bc5..f2dd99e96822 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -2447,7 +2447,9 @@ void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err, NLMSG_ERROR, payload, flags); errmsg = nlmsg_data(rep); errmsg->error = err; - memcpy(&errmsg->msg, nlh, payload > sizeof(*errmsg) ? nlh->nlmsg_len : sizeof(*nlh)); + memcpy(&errmsg->msg, nlh, sizeof(*nlh)); + if (payload > sizeof(*errmsg)) + memcpy(errmsg->msg.contents, nlh->contents, nlh->nlmsg_len - sizeof(*nlh)); if (nlk_has_extack && extack) { if (extack->_msg) { -- 2.30.2