1 files changed, 23 insertions, 12 deletions

diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
index 51c4d7fef1d2..2b1129a7a94a 100644
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -1174,25 +1174,36 @@ out:
  */
 void sctp_chunk_assign_ssn(struct sctp_chunk *chunk)
 {
+        struct sctp_datamsg *msg;
+        struct sctp_chunk *lchunk;
+        struct sctp_stream *stream;
         __u16 ssn;
         __u16 sid;
 
         if (chunk->has_ssn)
                 return;
 
-        /* This is the last possible instant to assign a SSN. */
-        if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) {
-                ssn = 0;
-        } else {
-                sid = ntohs(chunk->subh.data_hdr->stream);
-                if (chunk->chunk_hdr->flags & SCTP_DATA_LAST_FRAG)
-                        ssn = sctp_ssn_next(&chunk->asoc->ssnmap->out, sid);
-                else
-                        ssn = sctp_ssn_peek(&chunk->asoc->ssnmap->out, sid);
-        }
+        /* All fragments will be on the same stream */
+        sid = ntohs(chunk->subh.data_hdr->stream);
+        stream = &chunk->asoc->ssnmap->out;
 
-        chunk->subh.data_hdr->ssn = htons(ssn);
-        chunk->has_ssn = 1;
+        /* Now assign the sequence number to the entire message.
+         * All fragments must have the same stream sequence number.
+         */
+        msg = chunk->msg;
+        list_for_each_entry(lchunk, &msg->chunks, frag_list) {
+                if (lchunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) {
+                        ssn = 0;
+                } else {
+                        if (lchunk->chunk_hdr->flags & SCTP_DATA_LAST_FRAG)
+                                ssn = sctp_ssn_next(stream, sid);
+                        else
+                                ssn = sctp_ssn_peek(stream, sid);
+                }
+
+                lchunk->subh.data_hdr->ssn = htons(ssn);
+                lchunk->has_ssn = 1;
+        }
 }
 
 /* Helper function to assign a TSN if needed.  This assumes that both