From e6e4d9ed11fb1fab8b3256a3dc14d71b5e984ac4 Mon Sep 17 00:00:00 2001
From: Patrick McHardy <kaber@trash.net>
Date: Mon, 16 May 2011 14:45:39 +0200
Subject: [PATCH] netfilter: nf_ct_sip: fix SDP parsing in TCP SIP messages for
some Cisco phones
Some Cisco phones do not place the Content-Length field at the end of the
SIP message. This is valid, due to a misunderstanding of the specification
the parser expects the SDP body to start directly after the Content-Length
field. Fix the parser to scan for \r\n\r\n to locate the beginning of the
SDP body.
Reported-by: Teresa Kang <teresa_kang@gemtek.com.tw>
Signed-off-by: Patrick McHardy <kaber@trash.net>
---
net/netfilter/nf_conntrack_sip.c | 14 ++++++++++----
1 file changed, 10 insertions(+), 4 deletions(-)
diff --git a/net/netfilter/nf_conntrack_sip.c b/net/netfilter/nf_conntrack_sip.c
index 1f81abde131f..c05c0dc33499 100644
--- a/net/netfilter/nf_conntrack_sip.c
+++ b/net/netfilter/nf_conntrack_sip.c
@@ -1419,6 +1419,7 @@ static int sip_help_tcp(struct sk_buff *skb, unsigned int protoff,
const char *dptr, *end;
s16 diff, tdiff = 0;
int ret = NF_ACCEPT;
+ bool term;
typeof(nf_nat_sip_seq_adjust_hook) nf_nat_sip_seq_adjust;
if (ctinfo != IP_CT_ESTABLISHED &&
@@ -1453,10 +1454,15 @@ static int sip_help_tcp(struct sk_buff *skb, unsigned int protoff,
if (dptr + matchoff == end)
break;
- if (end + strlen("\r\n\r\n") > dptr + datalen)
- break;
- if (end[0] != '\r' || end[1] != '\n' ||
- end[2] != '\r' || end[3] != '\n')
+ term = false;
+ for (; end + strlen("\r\n\r\n") <= dptr + datalen; end++) {
+ if (end[0] == '\r' && end[1] == '\n' &&
+ end[2] == '\r' && end[3] == '\n') {
+ term = true;
+ break;
+ }
+ }
+ if (!term)
break;
end += strlen("\r\n\r\n") + clen;
--
2.20.1