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