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 DF894C433F5 for ; Mon, 21 Mar 2022 14:14:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1349122AbiCUOPa (ORCPT ); Mon, 21 Mar 2022 10:15:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38336 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1349604AbiCUOId (ORCPT ); Mon, 21 Mar 2022 10:08:33 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 558291B7B5; Mon, 21 Mar 2022 07:03:06 -0700 (PDT) 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 dfw.source.kernel.org (Postfix) with ESMTPS id 9F6B661350; Mon, 21 Mar 2022 14:02:58 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id ACC41C340E8; Mon, 21 Mar 2022 14:02:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1647871378; bh=2nO093whqQ/sqbYqWbv0LaogH00/S1O/HY0QpO+NfNU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uqwUb/iCbeAiGiH6bOubamMb0i0uW3ZAg+C8v54TG9rDDjbseI5zc3tvU32XFWxJ8 jwKryWbIpPNP3K3PwOd/+kLeyVK/uYBK4XM1IO2XHFvt6pxYXC1ZUJFqrh1bYhsYTl OzZi9PNmaleALC0ulor5HDKmBUnlktbunm++uz+k= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Xiumei Mu , Sabrina Dubroca , Steffen Klassert , Sasha Levin Subject: [PATCH 5.16 09/37] esp6: fix check on ipv6_skip_exthdrs return value Date: Mon, 21 Mar 2022 14:52:51 +0100 Message-Id: <20220321133221.564244907@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220321133221.290173884@linuxfoundation.org> References: <20220321133221.290173884@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Sabrina Dubroca [ Upstream commit 4db4075f92af2b28f415fc979ab626e6b37d67b6 ] Commit 5f9c55c8066b ("ipv6: check return value of ipv6_skip_exthdr") introduced an incorrect check, which leads to all ESP packets over either TCPv6 or UDPv6 encapsulation being dropped. In this particular case, offset is negative, since skb->data points to the ESP header in the following chain of headers, while skb->network_header points to the IPv6 header: IPv6 | ext | ... | ext | UDP | ESP | ... That doesn't seem to be a problem, especially considering that if we reach esp6_input_done2, we're guaranteed to have a full set of headers available (otherwise the packet would have been dropped earlier in the stack). However, it means that the return value will (intentionally) be negative. We can make the test more specific, as the expected return value of ipv6_skip_exthdr will be the (negated) size of either a UDP header, or a TCP header with possible options. In the future, we should probably either make ipv6_skip_exthdr explicitly accept negative offsets (and adjust its return value for error cases), or make ipv6_skip_exthdr only take non-negative offsets (and audit all callers). Fixes: 5f9c55c8066b ("ipv6: check return value of ipv6_skip_exthdr") Reported-by: Xiumei Mu Signed-off-by: Sabrina Dubroca Signed-off-by: Steffen Klassert Signed-off-by: Sasha Levin --- net/ipv6/esp6.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/net/ipv6/esp6.c b/net/ipv6/esp6.c index b7b573085bd5..5023f59a5b96 100644 --- a/net/ipv6/esp6.c +++ b/net/ipv6/esp6.c @@ -813,8 +813,7 @@ int esp6_input_done2(struct sk_buff *skb, int err) struct tcphdr *th; offset = ipv6_skip_exthdr(skb, offset, &nexthdr, &frag_off); - - if (offset < 0) { + if (offset == -1) { err = -EINVAL; goto out; } -- 2.34.1