From 8179db52c2c8692cdabf818bf1b7fdf3ad43b2db Mon Sep 17 00:00:00 2001
From: Mark Johnston <markj@FreeBSD.org>
Date: Fri, 1 Jul 2022 11:04:15 -0400
Subject: [PATCH] crypto: Fix the NULL_HMAC finalizer

The current implementation leaves the digest buffer partially
uninitialized.

Reported by:	syzkaller
Reviewed by:	jhb
MFC after:	1 week
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D35547
---
 sys/opencrypto/xform_null.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/sys/opencrypto/xform_null.c b/sys/opencrypto/xform_null.c
index e070a4a97142..160e1d867792 100644
--- a/sys/opencrypto/xform_null.c
+++ b/sys/opencrypto/xform_null.c
@@ -135,6 +135,5 @@ null_update(void *ctx, const void *buf, u_int len)
 static void
 null_final(uint8_t *buf, void *ctx)
 {
-	if (buf != (uint8_t *) 0)
-		bzero(buf, 12);
+	bzero(buf, NULL_HASH_LEN);
 }