1 files changed, 25 insertions, 2 deletions

diff --git a/net/sctp/input.c b/net/sctp/input.c
index ca6b022b1df2..d354a23972d4 100644
--- a/net/sctp/input.c
+++ b/net/sctp/input.c
@@ -430,6 +430,9 @@ struct sock *sctp_err_lookup(int family, struct sk_buff *skb,
         struct sock *sk = NULL;
         struct sctp_association *asoc;
         struct sctp_transport *transport = NULL;
+        struct sctp_init_chunk *chunkhdr;
+        __u32 vtag = ntohl(sctphdr->vtag);
+        int len = skb->len - ((void *)sctphdr - (void *)skb->data);
 
         *app = NULL; *tpp = NULL;
 
@@ -451,8 +454,28 @@ struct sock *sctp_err_lookup(int family, struct sk_buff *skb,
 
         sk = asoc->base.sk;
 
-        if (ntohl(sctphdr->vtag) != asoc->c.peer_vtag) {
-                ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
+        /* RFC 4960, Appendix C. ICMP Handling
+         *
+         * ICMP6) An implementation MUST validate that the Verification Tag
+         * contained in the ICMP message matches the Verification Tag of
+         * the peer.  If the Verification Tag is not 0 and does NOT
+         * match, discard the ICMP message.  If it is 0 and the ICMP
+         * message contains enough bytes to verify that the chunk type is
+         * an INIT chunk and that the Initiate Tag matches the tag of the
+         * peer, continue with ICMP7.  If the ICMP message is too short
+         * or the chunk type or the Initiate Tag does not match, silently
+         * discard the packet.
+         */
+        if (vtag == 0) {
+                chunkhdr = (struct sctp_init_chunk *)((void *)sctphdr
+                                + sizeof(struct sctphdr));
+                if (len < sizeof(struct sctphdr) + sizeof(sctp_chunkhdr_t)
+                          + sizeof(__be32) ||
+                    chunkhdr->chunk_hdr.type != SCTP_CID_INIT ||
+                    ntohl(chunkhdr->init_hdr.init_tag) != asoc->c.my_vtag) {
+                        goto out;
+                }
+        } else if (vtag != asoc->c.peer_vtag) {
                 goto out;
         }