[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 5259abd..0416073 100644 (file)
--- 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 9cccc32..0c6da49 100644 (file)
--- 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;
                }