sctp: Fix malformed "Invalid Stream Identifier" error

The "Invalid Stream Identifier" error has a 16 bit reserved
field at the end, thus making the parameter length be 8 bytes.
We've never supplied that reserved field making wireshark
tag the packet as malformed.

Reported-by: Chris Dischino <cdischino@sonusnet.com>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>

1 files changed, 9 insertions, 4 deletions

diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
index 9d881a61ac02..9e732916b671 100644
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -987,7 +987,10 @@ static void *sctp_addto_param(struct sctp_chunk *chunk, int len,
 
         target = skb_put(chunk->skb, len);
 
-        memcpy(target, data, len);
+        if (data)
+                memcpy(target, data, len);
+        else
+                memset(target, 0, len);
 
         /* Adjust the chunk length field.  */
         chunk->chunk_hdr->length = htons(chunklen + len);
@@ -1129,16 +1132,18 @@ nodata:
 struct sctp_chunk *sctp_make_op_error(const struct sctp_association *asoc,
                                  const struct sctp_chunk *chunk,
                                  __be16 cause_code, const void *payload,
-                                 size_t paylen)
+                                 size_t paylen, size_t reserve_tail)
 {
         struct sctp_chunk *retval;
 
-        retval = sctp_make_op_error_space(asoc, chunk, paylen);
+        retval = sctp_make_op_error_space(asoc, chunk, paylen + reserve_tail);
         if (!retval)
                 goto nodata;
 
-        sctp_init_cause(retval, cause_code, paylen);
+        sctp_init_cause(retval, cause_code, paylen + reserve_tail);
         sctp_addto_chunk(retval, paylen, payload);
+        if (reserve_tail)
+                sctp_addto_param(retval, reserve_tail, NULL);
 
 nodata:
         return retval;