From c118fb92386cc6f81aadf2a64473e94bac938cee Mon Sep 17 00:00:00 2001
From: DesWurstes <DesWurstes@users.noreply.github.com>
Date: Sat, 7 Jul 2018 12:10:53 +0300
Subject: [PATCH] modes/ocb128.c: improve the calculation of double mask

CLA: trivial

Reviewed-by: Andy Polyakov <appro@openssl.org>
Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/6667)
---
 crypto/modes/ocb128.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crypto/modes/ocb128.c b/crypto/modes/ocb128.c
index 76591e6992..72e6ea9b58 100644
--- a/crypto/modes/ocb128.c
+++ b/crypto/modes/ocb128.c
@@ -74,7 +74,7 @@ static void ocb_double(OCB_BLOCK *in, OCB_BLOCK *out)
      */
     mask = in->c[0] & 0x80;
     mask >>= 7;
-    mask *= 135;
+    mask = (0 - mask) & 0x87;
 
     ocb_block_lshift(in->c, 1, out->c);