Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Corentin Labbe <clabbe.montjoie@gmail.com>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.14 072/193] crypto: sun4i-ss - Fix invalid calculation of hash end
Date:   Wed, 29 May 2019 20:05:26 -0700
Message-Id: <20190530030459.261512234@linuxfoundation.org>
In-Reply-To: <20190530030446.953835040@linuxfoundation.org>
References: <20190530030446.953835040@linuxfoundation.org>
User-Agent: quilt/0.66
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

[ Upstream commit f87391558acf816b48f325a493d81d45dec40da0 ]

When nbytes < 4, end is wronlgy set to a negative value which, due to
uint, is then interpreted to a large value leading to a deadlock in the
following code.

This patch fix this problem.

Fixes: 6298e948215f ("crypto: sunxi-ss - Add Allwinner Security System crypto accelerator")
Signed-off-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/crypto/sunxi-ss/sun4i-ss-hash.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/crypto/sunxi-ss/sun4i-ss-hash.c b/drivers/crypto/sunxi-ss/sun4i-ss-hash.c
index a4b5ff2b72f87..f6936bb3b7be4 100644
--- a/drivers/crypto/sunxi-ss/sun4i-ss-hash.c
+++ b/drivers/crypto/sunxi-ss/sun4i-ss-hash.c
@@ -240,7 +240,10 @@ static int sun4i_hash(struct ahash_request *areq)
 		}
 	} else {
 		/* Since we have the flag final, we can go up to modulo 4 */
-		end = ((areq->nbytes + op->len) / 4) * 4 - op->len;
+		if (areq->nbytes < 4)
+			end = 0;
+		else
+			end = ((areq->nbytes + op->len) / 4) * 4 - op->len;
 	}
 
 	/* TODO if SGlen % 4 and !op->len then DMA */
-- 
2.20.1