1 files changed, 12 insertions, 0 deletions

diff --git a/net/sctp/chunk.c b/net/sctp/chunk.c
index 77fb7b06a9c4..619d0f2dee51 100644
--- a/net/sctp/chunk.c
+++ b/net/sctp/chunk.c
@@ -194,6 +194,18 @@ struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc,
 
         max = asoc->frag_point;
 
+        /* If the the peer requested that we authenticate DATA chunks
+         * we need to accound for bundling of the AUTH chunks along with
+         * DATA.
+         */
+        if (sctp_auth_send_cid(SCTP_CID_DATA, asoc)) {
+                struct sctp_hmac *hmac_desc = sctp_auth_asoc_get_hmac(asoc);
+
+                if (hmac_desc)
+                        max -= WORD_ROUND(sizeof(sctp_auth_chunk_t) +
+                                            hmac_desc->hmac_len);
+        }
+
         whole = 0;
         first_len = max;