netdev - [PATCH 2/2] netfilter: nf_ct_sip: fix SDP parsing in TCP SIP messages for some Cisco phones

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1305610014-3056-3-git-send-email-kaber@trash.net>
Date:	Tue, 17 May 2011 07:26:54 +0200
From:	kaber@...sh.net
To:	davem@...emloft.net
Cc:	netfilter-devel@...r.kernel.org, netdev@...r.kernel.org
Subject: [PATCH 2/2] netfilter: nf_ct_sip: fix SDP parsing in TCP SIP messages for some Cisco phones

From: Patrick McHardy <kaber@...sh.net>

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@...tek.com.tw>
Signed-off-by: Patrick McHardy <kaber@...sh.net>
---
 net/netfilter/nf_conntrack_sip.c |   14 ++++++++++----
 1 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/net/netfilter/nf_conntrack_sip.c b/net/netfilter/nf_conntrack_sip.c
index 1f81abd..c05c0dc 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;
 
-- 
1.7.2.3

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html