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 73407C07E9D for ; Mon, 26 Sep 2022 10:15:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234495AbiIZKPU (ORCPT ); Mon, 26 Sep 2022 06:15:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45814 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234808AbiIZKPC (ORCPT ); Mon, 26 Sep 2022 06:15:02 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 375D7476D9; Mon, 26 Sep 2022 03:14:12 -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 6BCF160BFE; Mon, 26 Sep 2022 10:14:11 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7BD64C433D7; Mon, 26 Sep 2022 10:14:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1664187250; bh=bbnmpylZreDUTDme6h0ibI/W2LjDmiXSyGclQyVmXck=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=SHqDqZw4g8cNQIMprKGVU/96P6YIDEfMbmx/9f28ZYY+o/dZ+yZgNSu0qbXCyMuGQ UGTZOufmt/FX1taF4XcVNI6InvCYmgxL6uGiHh0dhBbQ67f1gB7ytoHpm6+3GnlA6i B03Y62XSzt4r6TDfulyh46qvP17qe7ES/3yQgJc0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, David Leadbeater , Florian Westphal , Sasha Levin Subject: [PATCH 4.9 19/30] netfilter: nf_conntrack_irc: Tighten matching on DCC message Date: Mon, 26 Sep 2022 12:11:50 +0200 Message-Id: <20220926100736.846278933@linuxfoundation.org> X-Mailer: git-send-email 2.37.3 In-Reply-To: <20220926100736.153157100@linuxfoundation.org> References: <20220926100736.153157100@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: David Leadbeater [ Upstream commit e8d5dfd1d8747b56077d02664a8838c71ced948e ] CTCP messages should only be at the start of an IRC message, not anywhere within it. While the helper only decodes packes in the ORIGINAL direction, its possible to make a client send a CTCP message back by empedding one into a PING request. As-is, thats enough to make the helper believe that it saw a CTCP message. Fixes: 869f37d8e48f ("[NETFILTER]: nf_conntrack/nf_nat: add IRC helper port") Signed-off-by: David Leadbeater Signed-off-by: Florian Westphal Signed-off-by: Sasha Levin --- net/netfilter/nf_conntrack_irc.c | 34 ++++++++++++++++++++++++++------ 1 file changed, 28 insertions(+), 6 deletions(-) diff --git a/net/netfilter/nf_conntrack_irc.c b/net/netfilter/nf_conntrack_irc.c index c6a8bdc3a226..5d630288f86c 100644 --- a/net/netfilter/nf_conntrack_irc.c +++ b/net/netfilter/nf_conntrack_irc.c @@ -150,15 +150,37 @@ static int help(struct sk_buff *skb, unsigned int protoff, data = ib_ptr; data_limit = ib_ptr + skb->len - dataoff; - /* strlen("\1DCC SENT t AAAAAAAA P\1\n")=24 - * 5+MINMATCHLEN+strlen("t AAAAAAAA P\1\n")=14 */ - while (data < data_limit - (19 + MINMATCHLEN)) { - if (memcmp(data, "\1DCC ", 5)) { + /* Skip any whitespace */ + while (data < data_limit - 10) { + if (*data == ' ' || *data == '\r' || *data == '\n') + data++; + else + break; + } + + /* strlen("PRIVMSG x ")=10 */ + if (data < data_limit - 10) { + if (strncasecmp("PRIVMSG ", data, 8)) + goto out; + data += 8; + } + + /* strlen(" :\1DCC SENT t AAAAAAAA P\1\n")=26 + * 7+MINMATCHLEN+strlen("t AAAAAAAA P\1\n")=26 + */ + while (data < data_limit - (21 + MINMATCHLEN)) { + /* Find first " :", the start of message */ + if (memcmp(data, " :", 2)) { data++; continue; } + data += 2; + + /* then check that place only for the DCC command */ + if (memcmp(data, "\1DCC ", 5)) + goto out; data += 5; - /* we have at least (19+MINMATCHLEN)-5 bytes valid data left */ + /* we have at least (21+MINMATCHLEN)-(2+5) bytes valid data left */ iph = ip_hdr(skb); pr_debug("DCC found in master %pI4:%u %pI4:%u\n", @@ -174,7 +196,7 @@ static int help(struct sk_buff *skb, unsigned int protoff, pr_debug("DCC %s detected\n", dccprotos[i]); /* we have at least - * (19+MINMATCHLEN)-5-dccprotos[i].matchlen bytes valid + * (21+MINMATCHLEN)-7-dccprotos[i].matchlen bytes valid * data left (== 14/13 bytes) */ if (parse_dcc(data, data_limit, &dcc_ip, &dcc_port, &addr_beg_p, &addr_end_p)) { -- 2.35.1