From: Patrick McHardy <kaber@trash.net>
Date: Tue, 2 May 2006 21:23:07 +0000 (+0200)
Subject: [PATCH] NETFILTER: SCTP conntrack: fix infinite loop (CVE-2006-1527)
X-Git-Url: http://www.kernel.org/git/?p=linux/kernel/git/stable/linux-2.6.16.y.git;a=commitdiff;h=25b6badde42165b717e3c232e4992b3f6761920a

[PATCH] NETFILTER: SCTP conntrack: fix infinite loop (CVE-2006-1527)

[NETFILTER]: SCTP conntrack: fix infinite loop

fix infinite loop in the SCTP-netfilter code: check SCTP chunk size to
guarantee progress of for_each_sctp_chunk(). (all other uses of
for_each_sctp_chunk() are preceded by do_basic_checks(), so this fix
should be complete.)

Based on patch from Ingo Molnar <mingo@elte.hu>

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

--- a/net/ipv4/netfilter/ip_conntrack_proto_sctp.c
+++ b/net/ipv4/netfilter/ip_conntrack_proto_sctp.c
@@ -235,12 +235,15 @@ static int do_basic_checks(struct ip_con
 			flag = 1;
 		}
 
-		/* Cookie Ack/Echo chunks not the first OR 
-		   Init / Init Ack / Shutdown compl chunks not the only chunks */
-		if ((sch->type == SCTP_CID_COOKIE_ACK 
+		/*
+		 * Cookie Ack/Echo chunks not the first OR
+		 * Init / Init Ack / Shutdown compl chunks not the only chunks
+		 * OR zero-length.
+		 */
+		if (((sch->type == SCTP_CID_COOKIE_ACK
 			|| sch->type == SCTP_CID_COOKIE_ECHO
 			|| flag)
-		     && count !=0 ) {
+		      && count !=0) || !sch->length) {
 			DEBUGP("Basic checks failed\n");
 			return 1;
 		}
--- a/net/netfilter/nf_conntrack_proto_sctp.c
+++ b/net/netfilter/nf_conntrack_proto_sctp.c
@@ -240,12 +240,15 @@ static int do_basic_checks(struct nf_con
 			flag = 1;
 		}
 
-		/* Cookie Ack/Echo chunks not the first OR 
-		   Init / Init Ack / Shutdown compl chunks not the only chunks */
-		if ((sch->type == SCTP_CID_COOKIE_ACK 
+		/*
+		 * Cookie Ack/Echo chunks not the first OR
+		 * Init / Init Ack / Shutdown compl chunks not the only chunks
+		 * OR zero-length.
+		 */
+		if (((sch->type == SCTP_CID_COOKIE_ACK
 			|| sch->type == SCTP_CID_COOKIE_ECHO
 			|| flag)
-		     && count !=0 ) {
+		      && count !=0) || !sch->length) {
 			DEBUGP("Basic checks failed\n");
 			return 1;
 		}