diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index affee44bd38e..cccc662561aa 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -312,7 +312,8 @@ struct sctp_cookie {
 
 	__u8 auth_random[sizeof(struct sctp_paramhdr) +
 			 SCTP_AUTH_RANDOM_LENGTH];
-	__u8 auth_hmacs[SCTP_AUTH_NUM_HMACS * sizeof(__u16) + 2];
+	__u8 auth_hmacs[sizeof(struct sctp_paramhdr) +
+			SCTP_AUTH_NUM_HMACS * sizeof(__u16)];
 	__u8 auth_chunks[sizeof(struct sctp_paramhdr) + SCTP_AUTH_MAX_CHUNKS];
 
 	/* This is a shim for my peer's INIT packet, followed by