From patchwork Mon Jun 21 16:14:24 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 465084 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=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 A3A59C49EA2 for ; Mon, 21 Jun 2021 16:25:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 88CD961405 for ; Mon, 21 Jun 2021 16:25:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231488AbhFUQ1z (ORCPT ); Mon, 21 Jun 2021 12:27:55 -0400 Received: from mail.kernel.org ([198.145.29.99]:48302 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231810AbhFUQ0H (ORCPT ); Mon, 21 Jun 2021 12:26:07 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id AE83361380; Mon, 21 Jun 2021 16:22:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1624292532; bh=bMUePvQ+VvmHOsBXni+Ytx/Rw6NBxqGfrpuAv4o4N78=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=loxmNE9bC6cikC2iopXXUasKDV4JCYnKTxaLz9KxxD4HV0Nk1Gz93w20yHR7BQPL4 xKe2zS5AKzFvWbbmjNHIi489gKOae9UQmm/9XnMrjF1U4HtOexulwPk6YUeL7kqqIu PFUOG3gkxgpMEEAX8jNlYlRhXLgqlnSfvbMNS5i8= 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 5.10 034/146] netfilter: synproxy: Fix out of bounds when parsing TCP options Date: Mon, 21 Jun 2021 18:14:24 +0200 Message-Id: <20210621154912.452507619@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210621154911.244649123@linuxfoundation.org> References: <20210621154911.244649123@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@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 d7d34a62d3bf..2fc4ae960769 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;