From: Patrick McHardy <kaber@trash.net>
Date: Wed, 11 Jul 2007 06:24:52 +0000 (-0700)
Subject: [NETFILTER]: {ip, nf}_conntrack_sctp: fix remotely triggerable NULL ptr dereference... 
X-Git-Tag: v2.6.23-rc1~1109^2~14
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=99d24edeb6abc6ca3a0d0fbdb83c664c04403c8c;p=linux-2.6

[NETFILTER]: {ip, nf}_conntrack_sctp: fix remotely triggerable NULL ptr dereference (CVE-2007-2876)

When creating a new connection by sending an unknown chunk type, we
don't transition to a valid state, causing a NULL pointer dereference
in sctp_packet when accessing sctp_timeouts[SCTP_CONNTRACK_NONE].

Fix by don't creating new conntrack entry if initial state is invalid.

Noticed by Vilmos Nebehaj <vilmos.nebehaj@ramsys.hu>

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/netfilter/nf_conntrack_proto_sctp.c b/net/netfilter/nf_conntrack_proto_sctp.c
index 265769e500..debfe61378 100644
--- a/net/netfilter/nf_conntrack_proto_sctp.c
+++ b/net/netfilter/nf_conntrack_proto_sctp.c
@@ -431,7 +431,8 @@ static int sctp_new(struct nf_conn *conntrack, const struct sk_buff *skb,
 					 SCTP_CONNTRACK_NONE, sch->type);
 
 		/* Invalid: delete conntrack */
-		if (newconntrack == SCTP_CONNTRACK_MAX) {
+		if (newconntrack == SCTP_CONNTRACK_NONE ||
+		    newconntrack == SCTP_CONNTRACK_MAX) {
 			pr_debug("nf_conntrack_sctp: invalid new deleting.\n");
 			return 0;
 		}