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=-12.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 6FA04C433E2 for ; Tue, 8 Sep 2020 20:16:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 467B020936 for ; Tue, 8 Sep 2020 20:16:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729717AbgIHUQA (ORCPT ); Tue, 8 Sep 2020 16:16:00 -0400 Received: from correo.us.es ([193.147.175.20]:60758 "EHLO mail.us.es" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729529AbgIHPKD (ORCPT ); Tue, 8 Sep 2020 11:10:03 -0400 Received: from antivirus1-rhel7.int (unknown [192.168.2.11]) by mail.us.es (Postfix) with ESMTP id 273001F0CF8 for ; Tue, 8 Sep 2020 17:09:55 +0200 (CEST) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id 19AA8DA7B6 for ; Tue, 8 Sep 2020 17:09:55 +0200 (CEST) Received: by antivirus1-rhel7.int (Postfix, from userid 99) id 0F0F0DA793; Tue, 8 Sep 2020 17:09:55 +0200 (CEST) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id D3BB3DA78E; Tue, 8 Sep 2020 17:09:52 +0200 (CEST) Received: from 192.168.1.97 (192.168.1.97) by antivirus1-rhel7.int (F-Secure/fsigk_smtp/550/antivirus1-rhel7.int); Tue, 08 Sep 2020 17:09:52 +0200 (CEST) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/antivirus1-rhel7.int) Received: from localhost.localdomain (unknown [90.77.255.23]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: pneira@us.es) by entrada.int (Postfix) with ESMTPSA id A5E354301DE1; Tue, 8 Sep 2020 17:09:52 +0200 (CEST) X-SMTPAUTHUS: auth mail.us.es From: Pablo Neira Ayuso To: netfilter-devel@vger.kernel.org Cc: davem@davemloft.net, netdev@vger.kernel.org, kuba@kernel.org Subject: [PATCH 1/5] netfilter: ctnetlink: add a range check for l3/l4 protonum Date: Tue, 8 Sep 2020 17:09:43 +0200 Message-Id: <20200908150947.12623-2-pablo@netfilter.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200908150947.12623-1-pablo@netfilter.org> References: <20200908150947.12623-1-pablo@netfilter.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Virus-Scanned: ClamAV using ClamSMTP Sender: netfilter-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org From: Will McVicker The indexes to the nf_nat_l[34]protos arrays come from userspace. So check the tuple's family, e.g. l3num, when creating the conntrack in order to prevent an OOB memory access during setup. Here is an example kernel panic on 4.14.180 when userspace passes in an index greater than NFPROTO_NUMPROTO. Internal error: Oops - BUG: 0 [#1] PREEMPT SMP Modules linked in:... Process poc (pid: 5614, stack limit = 0x00000000a3933121) CPU: 4 PID: 5614 Comm: poc Tainted: G S W O 4.14.180-g051355490483 Hardware name: Qualcomm Technologies, Inc. SM8150 V2 PM8150 Google Inc. MSM task: 000000002a3dfffe task.stack: 00000000a3933121 pc : __cfi_check_fail+0x1c/0x24 lr : __cfi_check_fail+0x1c/0x24 ... Call trace: __cfi_check_fail+0x1c/0x24 name_to_dev_t+0x0/0x468 nfnetlink_parse_nat_setup+0x234/0x258 ctnetlink_parse_nat_setup+0x4c/0x228 ctnetlink_new_conntrack+0x590/0xc40 nfnetlink_rcv_msg+0x31c/0x4d4 netlink_rcv_skb+0x100/0x184 nfnetlink_rcv+0xf4/0x180 netlink_unicast+0x360/0x770 netlink_sendmsg+0x5a0/0x6a4 ___sys_sendmsg+0x314/0x46c SyS_sendmsg+0xb4/0x108 el0_svc_naked+0x34/0x38 This crash is not happening since 5.4+, however, ctnetlink still allows for creating entries with unsupported layer 3 protocol number. Fixes: c1d10adb4a521 ("[NETFILTER]: Add ctnetlink port for nf_conntrack") Signed-off-by: Will McVicker [pablo@netfilter.org: rebased original patch on top of nf.git] Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_conntrack_netlink.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c index 832eabecfbdd..d65846aa8059 100644 --- a/net/netfilter/nf_conntrack_netlink.c +++ b/net/netfilter/nf_conntrack_netlink.c @@ -1404,7 +1404,8 @@ ctnetlink_parse_tuple_filter(const struct nlattr * const cda[], if (err < 0) return err; - + if (l3num != NFPROTO_IPV4 && l3num != NFPROTO_IPV6) + return -EOPNOTSUPP; tuple->src.l3num = l3num; if (flags & CTA_FILTER_FLAG(CTA_IP_DST) || -- 2.20.1