1 files changed, 39 insertions, 0 deletions

diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
index 4c02875786ac..fa2ba543183d 100644
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -1111,6 +1111,41 @@ nodata:
         return retval;
 }
 
+struct sctp_chunk *sctp_make_auth(const struct sctp_association *asoc)
+{
+        struct sctp_chunk *retval;
+        struct sctp_hmac *hmac_desc;
+        struct sctp_authhdr auth_hdr;
+        __u8 *hmac;
+
+        /* Get the first hmac that the peer told us to use */
+        hmac_desc = sctp_auth_asoc_get_hmac(asoc);
+        if (unlikely(!hmac_desc))
+                return NULL;
+
+        retval = sctp_make_chunk(asoc, SCTP_CID_AUTH, 0,
+                        hmac_desc->hmac_len + sizeof(sctp_authhdr_t));
+        if (!retval)
+                return NULL;
+
+        auth_hdr.hmac_id = htons(hmac_desc->hmac_id);
+        auth_hdr.shkey_id = htons(asoc->active_key_id);
+
+        retval->subh.auth_hdr = sctp_addto_chunk(retval, sizeof(sctp_authhdr_t),
+                                                &auth_hdr);
+
+        hmac = skb_put(retval->skb, hmac_desc->hmac_len);
+        memset(hmac, 0, hmac_desc->hmac_len);
+
+        /* Adjust the chunk header to include the empty MAC */
+        retval->chunk_hdr->length =
+                htons(ntohs(retval->chunk_hdr->length) + hmac_desc->hmac_len);
+        retval->chunk_end = skb_tail_pointer(retval->skb);
+
+        return retval;
+}
+
+
 /********************************************************************
  * 2nd Level Abstractions
  ********************************************************************/
@@ -1225,6 +1260,10 @@ struct sctp_chunk *sctp_make_chunk(const struct sctp_association *asoc,
         retval->chunk_hdr = chunk_hdr;
         retval->chunk_end = ((__u8 *)chunk_hdr) + sizeof(struct sctp_chunkhdr);
 
+        /* Determine if the chunk needs to be authenticated */
+        if (sctp_auth_send_cid(type, asoc))
+                retval->auth = 1;
+
         /* Set the skb to the belonging sock for accounting.  */
         skb->sk = sk;