From patchwork Wed Nov 23 08:52:31 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 13053390 X-Patchwork-Delegate: kuba@kernel.org 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 86B32C43219 for ; Wed, 23 Nov 2022 10:10:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237230AbiKWKKP (ORCPT ); Wed, 23 Nov 2022 05:10:15 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33620 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236442AbiKWKI4 (ORCPT ); Wed, 23 Nov 2022 05:08:56 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 085CD10579; Wed, 23 Nov 2022 01:58:45 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id A4F77B81EF1; Wed, 23 Nov 2022 09:58:43 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8DB87C433D6; Wed, 23 Nov 2022 09:58:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1669197522; bh=m6MbNbll0gZxzTxmpyO62Y8I/bMY5gacCHv+7TeqXy8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=oQKAp7C0eXGRDmI34dMa520kmbpnrk7i/7+42DV/bUal0RYf3lUP/MTVnLe8OPdpT tcSBCBfpV7OA5nPozvPif9TsRqsx8ZZw3P55QuCIj79SVBroZbQbc+scHnl3kQKHOP /rQ35kQLZHPpUecgfgbP6TFCaYA7hNy+KU4j+IJY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jakub Kicinski , Pablo Neira Ayuso , Jozsef Kadlecsik , Florian Westphal , "David S. Miller" , Eric Dumazet , Paolo Abeni , syzbot , netfilter-devel@vger.kernel.org, coreteam@netfilter.org, netdev@vger.kernel.org, Kees Cook Subject: [PATCH 6.0 306/314] netlink: Bounds-check struct nlmsgerr creation Date: Wed, 23 Nov 2022 09:52:31 +0100 Message-Id: <20221123084639.430560487@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221123084625.457073469@linuxfoundation.org> References: <20221123084625.457073469@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org From: Kees Cook commit 710d21fdff9a98d621cd4e64167f3ef8af4e2fd1 upstream. In preparation for FORTIFY_SOURCE doing bounds-check on memcpy(), switch from __nlmsg_put to nlmsg_put(), and explain the bounds check for dealing with the memcpy() across a composite flexible array struct. Avoids this future run-time warning: memcpy: detected field-spanning write (size 32) of single field "&errmsg->msg" at net/netlink/af_netlink.c:2447 (size 16) Cc: Jakub Kicinski Cc: Pablo Neira Ayuso Cc: Jozsef Kadlecsik Cc: Florian Westphal Cc: "David S. Miller" Cc: Eric Dumazet Cc: Paolo Abeni Cc: syzbot Cc: netfilter-devel@vger.kernel.org Cc: coreteam@netfilter.org Cc: netdev@vger.kernel.org Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20220901071336.1418572-1-keescook@chromium.org Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/netfilter/ipset/ip_set_core.c | 8 +++++--- net/netlink/af_netlink.c | 8 +++++--- 2 files changed, 10 insertions(+), 6 deletions(-) --- a/net/netfilter/ipset/ip_set_core.c +++ b/net/netfilter/ipset/ip_set_core.c @@ -1719,11 +1719,13 @@ call_ad(struct net *net, struct sock *ct skb2 = nlmsg_new(payload, GFP_KERNEL); if (!skb2) return -ENOMEM; - rep = __nlmsg_put(skb2, NETLINK_CB(skb).portid, - nlh->nlmsg_seq, NLMSG_ERROR, payload, 0); + rep = nlmsg_put(skb2, NETLINK_CB(skb).portid, + nlh->nlmsg_seq, NLMSG_ERROR, payload, 0); errmsg = nlmsg_data(rep); errmsg->error = ret; - memcpy(&errmsg->msg, nlh, nlh->nlmsg_len); + unsafe_memcpy(&errmsg->msg, nlh, nlh->nlmsg_len, + /* Bounds checked by the skb layer. */); + cmdattr = (void *)&errmsg->msg + min_len; ret = nla_parse(cda, IPSET_ATTR_CMD_MAX, cmdattr, --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -2440,11 +2440,13 @@ void netlink_ack(struct sk_buff *in_skb, return; } - rep = __nlmsg_put(skb, NETLINK_CB(in_skb).portid, nlh->nlmsg_seq, - NLMSG_ERROR, payload, flags); + rep = nlmsg_put(skb, NETLINK_CB(in_skb).portid, nlh->nlmsg_seq, + NLMSG_ERROR, payload, flags); errmsg = nlmsg_data(rep); errmsg->error = err; - memcpy(&errmsg->msg, nlh, payload > sizeof(*errmsg) ? nlh->nlmsg_len : sizeof(*nlh)); + unsafe_memcpy(&errmsg->msg, nlh, payload > sizeof(*errmsg) + ? nlh->nlmsg_len : sizeof(*nlh), + /* Bounds checked by the skb layer. */); if (nlk_has_extack && extack) { if (extack->_msg) {