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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Ulrich Weber <ulrich.weber@riverbed.com>,
        Marco Angaroni <marcoangaroni@gmail.com>,
        Pablo Neira Ayuso <pablo@netfilter.org>,
        Michal Kubecek <mkubecek@suse.cz>
Subject: [PATCH 4.4 36/74] netfilter: nf_conntrack_sip: extend request line validation
Date:   Mon, 29 Jan 2018 13:56:41 +0100
Message-Id: <20180129123849.229429127@linuxfoundation.org>
In-Reply-To: <20180129123847.507563674@linuxfoundation.org>
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4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ulrich Weber <ulrich.weber@riverbed.com>

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>

---
 net/netfilter/nf_conntrack_sip.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- 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
 		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) {