From: Ulrich Weber Date: Mon, 24 Oct 2016 16:07:23 +0000 (+0200) Subject: netfilter: nf_conntrack_sip: extend request line validation X-Git-Tag: v4.9-rc6~27^2~23^2~10 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=444f901742d054a4cd5ff045871eac5131646cfb;p=karo-tx-linux.git netfilter: nf_conntrack_sip: extend request line validation 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 Acked-by: Marco Angaroni Signed-off-by: Pablo Neira Ayuso --- diff --git a/net/netfilter/nf_conntrack_sip.c b/net/netfilter/nf_conntrack_sip.c index 621b81c7bddc..c3fc14e021ec 100644 --- a/net/netfilter/nf_conntrack_sip.c +++ b/net/netfilter/nf_conntrack_sip.c @@ -1436,9 +1436,12 @@ 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) {