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=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, 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 994CAC48BE5 for ; Mon, 21 Jun 2021 16:18:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 856EB61206 for ; Mon, 21 Jun 2021 16:18:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231138AbhFUQUR (ORCPT ); Mon, 21 Jun 2021 12:20:17 -0400 Received: from mail.kernel.org ([198.145.29.99]:40024 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231137AbhFUQTr (ORCPT ); Mon, 21 Jun 2021 12:19:47 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 0DF8461261; Mon, 21 Jun 2021 16:17:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1624292249; bh=r5hFlrbhEQOPVmyOTnKJiMArl514zZExxYE1qGVCGuQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=blMdYytBr89E3Jb7S9mGDjhLuw+Rs6PbtUJUFoN+E38EFHKGjJCAbbz4H38YbUXu1 bqWe5O0PWfYXygmAfuGU2SV19F+jU1e49CfOPEcvVzY/G7Y9SGvD7kiIgmfR24qWDm FFSO/ebxNrEIDIo4lo8owKf1Ym+Tnmfqbj0A06J4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Young Xiao <92siuyang@gmail.com>, Maxim Mikityanskiy , Florian Westphal , "David S. Miller" , Sasha Levin Subject: [PATCH 5.4 20/90] netfilter: synproxy: Fix out of bounds when parsing TCP options Date: Mon, 21 Jun 2021 18:14:55 +0200 Message-Id: <20210621154904.817295060@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210621154904.159672728@linuxfoundation.org> References: <20210621154904.159672728@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: Maxim Mikityanskiy [ Upstream commit 5fc177ab759418c9537433e63301096e733fb915 ] The TCP option parser in synproxy (synproxy_parse_options) could read one byte out of bounds. When the length is 1, the execution flow gets into the loop, reads one byte of the opcode, and if the opcode is neither TCPOPT_EOL nor TCPOPT_NOP, it reads one more byte, which exceeds the length of 1. This fix is inspired by commit 9609dad263f8 ("ipv4: tcp_input: fix stack out of bounds when parsing TCP options."). v2 changes: Added an early return when length < 0 to avoid calling skb_header_pointer with negative length. Cc: Young Xiao <92siuyang@gmail.com> Fixes: 48b1de4c110a ("netfilter: add SYNPROXY core/target") Signed-off-by: Maxim Mikityanskiy Reviewed-by: Florian Westphal Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/netfilter/nf_synproxy_core.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/net/netfilter/nf_synproxy_core.c b/net/netfilter/nf_synproxy_core.c index 4bb4cfde28b4..c6c0d27caaed 100644 --- a/net/netfilter/nf_synproxy_core.c +++ b/net/netfilter/nf_synproxy_core.c @@ -31,6 +31,9 @@ synproxy_parse_options(const struct sk_buff *skb, unsigned int doff, int length = (th->doff * 4) - sizeof(*th); u8 buf[40], *ptr; + if (unlikely(length < 0)) + return false; + ptr = skb_header_pointer(skb, doff + sizeof(*th), length, buf); if (ptr == NULL) return false; @@ -47,6 +50,8 @@ synproxy_parse_options(const struct sk_buff *skb, unsigned int doff, length--; continue; default: + if (length < 2) + return true; opsize = *ptr++; if (opsize < 2) return true; -- 2.30.2