From: Patrick McHardy <kaber@trash.net>
Date: Tue, 2 May 2006 21:23:07 +0000 (+0200)
Subject: [NETFILTER] SCTP conntrack: fix infinite loop
X-Git-Tag: v2.6.17-rc4~54
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e17df688f7064dae1417ce425dd1e4b71d24d63b;p=linux-2.6

[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>

CVE-2006-1527

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---

diff --git a/net/ipv4/netfilter/ip_conntrack_proto_sctp.c b/net/ipv4/netfilter/ip_conntrack_proto_sctp.c
index 5259abd0fb..0416073c56 100644
--- 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_conntrack *conntrack,
 			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;
 		}
diff --git a/net/netfilter/nf_conntrack_proto_sctp.c b/net/netfilter/nf_conntrack_proto_sctp.c
index 9cccc325b6..0c6da496cf 100644
--- 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_conn *conntrack,
 			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;
 		}