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 49291C43219 for ; Mon, 21 Mar 2022 14:12:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1351863AbiCUOMB (ORCPT ); Mon, 21 Mar 2022 10:12:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35098 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1348944AbiCUOFK (ORCPT ); Mon, 21 Mar 2022 10:05:10 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4AF01181B2C; Mon, 21 Mar 2022 07:01:29 -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 ams.source.kernel.org (Postfix) with ESMTPS id ECD4BB816CE; Mon, 21 Mar 2022 14:01:25 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 444E9C340ED; Mon, 21 Mar 2022 14:01:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1647871284; bh=2nO093whqQ/sqbYqWbv0LaogH00/S1O/HY0QpO+NfNU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CiH/1Ha3UbvdZ/nBRLVJd6kUz7aGcQhQHHO4sa86nQubwWOQzW7oodf667KRnFCKV K8RokQAh33z3sinIIsyqf9akd+P2m6/zx/PvNpupsqFaMhl8XEpeWY4opG5fyyMfOd YKdnWim2sof2Fu26ow7wqzoW8IfaSpJH/AaT63Lc= 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 5.15 09/32] esp6: fix check on ipv6_skip_exthdrs return value Date: Mon, 21 Mar 2022 14:52:45 +0100 Message-Id: <20220321133220.833086671@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220321133220.559554263@linuxfoundation.org> References: <20220321133220.559554263@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