3 files changed, 57 insertions, 3 deletions

diff --git a/net/sctp/input.c b/net/sctp/input.c
index a49fa80b57b9..bf612d954d41 100644
--- a/net/sctp/input.c
+++ b/net/sctp/input.c
@@ -369,7 +369,7 @@ static void sctp_add_backlog(struct sock *sk, struct sk_buff *skb)
 void sctp_icmp_frag_needed(struct sock *sk, struct sctp_association *asoc,
                            struct sctp_transport *t, __u32 pmtu)
 {
-        if (!t || (t->pathmtu == pmtu))
+        if (!t || (t->pathmtu <= pmtu))
                 return;
 
         if (sock_owned_by_user(sk)) {
diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index d4c3fbc4671e..a6a0ea71ae93 100644
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -2544,6 +2544,7 @@ sctp_disposition_t sctp_sf_do_9_2_shutdown(const struct sctp_endpoint *ep,
         sctp_shutdownhdr_t *sdh;
         sctp_disposition_t disposition;
         struct sctp_ulpevent *ev;
+        __u32 ctsn;
 
         if (!sctp_vtag_verify(chunk, asoc))
                 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
@@ -2558,6 +2559,14 @@ sctp_disposition_t sctp_sf_do_9_2_shutdown(const struct sctp_endpoint *ep,
         sdh = (sctp_shutdownhdr_t *)chunk->skb->data;
         skb_pull(chunk->skb, sizeof(sctp_shutdownhdr_t));
         chunk->subh.shutdown_hdr = sdh;
+        ctsn = ntohl(sdh->cum_tsn_ack);
+
+        /* If Cumulative TSN Ack beyond the max tsn currently
+         * send, terminating the association and respond to the
+         * sender with an ABORT.
+         */
+        if (!TSN_lt(ctsn, asoc->next_tsn))
+                return sctp_sf_violation_ctsn(ep, asoc, type, arg, commands);
 
         /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT
          * When a peer sends a SHUTDOWN, SCTP delivers this notification to
@@ -2599,6 +2608,51 @@ out:
         return disposition;
 }
 
+/*
+ * sctp_sf_do_9_2_shut_ctsn
+ *
+ * Once an endpoint has reached the SHUTDOWN-RECEIVED state,
+ * it MUST NOT send a SHUTDOWN in response to a ULP request.
+ * The Cumulative TSN Ack of the received SHUTDOWN chunk
+ * MUST be processed.
+ */
+sctp_disposition_t sctp_sf_do_9_2_shut_ctsn(const struct sctp_endpoint *ep,
+                                           const struct sctp_association *asoc,
+                                           const sctp_subtype_t type,
+                                           void *arg,
+                                           sctp_cmd_seq_t *commands)
+{
+        struct sctp_chunk *chunk = arg;
+        sctp_shutdownhdr_t *sdh;
+
+        if (!sctp_vtag_verify(chunk, asoc))
+                return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
+
+        /* Make sure that the SHUTDOWN chunk has a valid length. */
+        if (!sctp_chunk_length_valid(chunk,
+                                      sizeof(struct sctp_shutdown_chunk_t)))
+                return sctp_sf_violation_chunklen(ep, asoc, type, arg,
+                                                  commands);
+
+        sdh = (sctp_shutdownhdr_t *)chunk->skb->data;
+
+        /* If Cumulative TSN Ack beyond the max tsn currently
+         * send, terminating the association and respond to the
+         * sender with an ABORT.
+         */
+        if (!TSN_lt(ntohl(sdh->cum_tsn_ack), asoc->next_tsn))
+                return sctp_sf_violation_ctsn(ep, asoc, type, arg, commands);
+
+        /* verify, by checking the Cumulative TSN Ack field of the
+         * chunk, that all its outstanding DATA chunks have been
+         * received by the SHUTDOWN sender.
+         */
+        sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN,
+                        SCTP_BE32(sdh->cum_tsn_ack));
+
+        return SCTP_DISPOSITION_CONSUME;
+}
+
 /* RFC 2960 9.2
  * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk
  * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination
diff --git a/net/sctp/sm_statetable.c b/net/sctp/sm_statetable.c
index dd4ddc40c0ad..5c8186d88c61 100644
--- a/net/sctp/sm_statetable.c
+++ b/net/sctp/sm_statetable.c
@@ -266,11 +266,11 @@ const sctp_sm_table_entry_t *sctp_sm_lookup_event(sctp_event_t event_type,
         /* SCTP_STATE_ESTABLISHED */ \
         TYPE_SCTP_FUNC(sctp_sf_do_9_2_shutdown), \
         /* SCTP_STATE_SHUTDOWN_PENDING */ \
-        TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
+        TYPE_SCTP_FUNC(sctp_sf_do_9_2_shutdown), \
         /* SCTP_STATE_SHUTDOWN_SENT */ \
         TYPE_SCTP_FUNC(sctp_sf_do_9_2_shutdown_ack), \
         /* SCTP_STATE_SHUTDOWN_RECEIVED */ \
-        TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
+        TYPE_SCTP_FUNC(sctp_sf_do_9_2_shut_ctsn), \
         /* SCTP_STATE_SHUTDOWN_ACK_SENT */ \
         TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
 } /* TYPE_SCTP_SHUTDOWN */