diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index f5c22d7..72aeae4 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -405,8 +405,9 @@
 /* The format of our cookie that we send to our peer. */
 struct sctp_signed_cookie {
 	__u8 signature[SCTP_SECRET_SIZE];
+	__u32 __pad;		/* force sctp_cookie alignment to 64 bits */
 	struct sctp_cookie c;
-};
+} __attribute__((packed));
 
 /* This is another convenience type to allocate memory for address
  * params for the maximum size and pass such structures around
diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
index 556c495..4fe1d6c 100644
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -1275,7 +1275,12 @@
 	unsigned int keylen;
 	char *key;
 
-	headersize = sizeof(sctp_paramhdr_t) + SCTP_SECRET_SIZE;
+	/* Header size is static data prior to the actual cookie, including
+	 * any padding.
+	 */
+	headersize = sizeof(sctp_paramhdr_t) + 
+		     (sizeof(struct sctp_signed_cookie) - 
+		      sizeof(struct sctp_cookie));
 	bodysize = sizeof(struct sctp_cookie)
 		+ ntohs(init_chunk->chunk_hdr->length) + addrs_len;
 
@@ -1362,7 +1367,12 @@
 	struct sk_buff *skb = chunk->skb;
 	struct timeval tv;
 
-	headersize = sizeof(sctp_chunkhdr_t) + SCTP_SECRET_SIZE;
+	/* Header size is static data prior to the actual cookie, including
+	 * any padding.
+	 */
+	headersize = sizeof(sctp_chunkhdr_t) +
+		     (sizeof(struct sctp_signed_cookie) - 
+		      sizeof(struct sctp_cookie));
 	bodysize = ntohs(chunk->chunk_hdr->length) - headersize;
 	fixed_size = headersize + sizeof(struct sctp_cookie);