[SCTP]: Correctly handle unexpected INIT-ACK chunk.

Consider the chunk as Out-of-the-Blue if we don't have
an endpoint.  Otherwise discard it as before.

Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 22 insertions, 0 deletions

diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index 2c165dc9fb71..fce1f602cde2 100644
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -1534,6 +1534,28 @@ sctp_disposition_t sctp_sf_do_5_2_2_dupinit(const struct sctp_endpoint *ep,
 }
 
 
+/*
+ * Unexpected INIT-ACK handler.
+ *
+ * Section 5.2.3
+ * If an INIT ACK received by an endpoint in any state other than the
+ * COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk.
+ * An unexpected INIT ACK usually indicates the processing of an old or
+ * duplicated INIT chunk.
+*/
+sctp_disposition_t sctp_sf_do_5_2_3_initack(const struct sctp_endpoint *ep,
+                                            const struct sctp_association *asoc,
+                                            const sctp_subtype_t type,
+                                            void *arg, sctp_cmd_seq_t *commands)
+{
+        /* Per the above section, we'll discard the chunk if we have an
+         * endpoint.  If this is an OOTB INIT-ACK, treat it as such.
+         */
+        if (ep == sctp_sk((sctp_get_ctl_sock()))->ep)
+                return sctp_sf_ootb(ep, asoc, type, arg, commands);
+        else
+                return sctp_sf_discard_chunk(ep, asoc, type, arg, commands);
+}
 
 /* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A')
  *