From: Ulrich Weber <ulrich.weber@riverbed.com>
Date: Mon, 24 Oct 2016 16:07:23 +0000 (+0200)
Subject: netfilter: nf_conntrack_sip: extend request line validation
X-Git-Tag: v3.18.93~22
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f1a49458d9ef2e02ad7163900eaa8cf15b083b78;p=thirdparty%2Fkernel%2Fstable.git

netfilter: nf_conntrack_sip: extend request line validation

commit 444f901742d054a4cd5ff045871eac5131646cfb upstream.

on SIP requests, so a fragmented TCP SIP packet from an allow header starting with
 INVITE,NOTIFY,OPTIONS,REFER,REGISTER,UPDATE,SUBSCRIBE
 Content-Length: 0

will not bet interpreted as an INVITE request. Also Request-URI must start with an alphabetic character.

Confirm with RFC 3261
 Request-Line   =  Method SP Request-URI SP SIP-Version CRLF

Fixes: 30f33e6dee80 ("[NETFILTER]: nf_conntrack_sip: support method specific request/response handling")
Signed-off-by: Ulrich Weber <ulrich.weber@riverbed.com>
Acked-by: Marco Angaroni <marcoangaroni@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Acked-by: Michal Kubecek <mkubecek@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/net/netfilter/nf_conntrack_sip.c b/net/netfilter/nf_conntrack_sip.c
index 885b4aba36956..1665c2159e4ba 100644
--- a/net/netfilter/nf_conntrack_sip.c
+++ b/net/netfilter/nf_conntrack_sip.c
@@ -1434,9 +1434,12 @@ static int process_sip_request(struct sk_buff *skb, unsigned int protoff,
 		handler = &sip_handlers[i];
 		if (handler->request == NULL)
 			continue;
-		if (*datalen < handler->len ||
+		if (*datalen < handler->len + 2 ||
 		    strncasecmp(*dptr, handler->method, handler->len))
 			continue;
+		if ((*dptr)[handler->len] != ' ' ||
+		    !isalpha((*dptr)[handler->len+1]))
+			continue;
 
 		if (ct_sip_get_header(ct, *dptr, 0, *datalen, SIP_HDR_CSEQ,
 				      &matchoff, &matchlen) <= 0) {