Received-SPF: pass (google.com: domain of linux-crypto-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Gaosheng Cui <cuigaosheng1@huawei.com>
To:     <herbert@gondor.apana.org.au>, <davem@davemloft.net>,
        <james.hartley@imgtec.com>, <abrestic@chromium.org>,
        <will.thomas@imgtec.com>, <cuigaosheng1@huawei.com>
CC:     <linux-crypto@vger.kernel.org>
Subject: [PATCH] crypto: img-hash - Fix variable dereferenced before check 'hdev->req'
Date:   Thu, 1 Dec 2022 14:25:26 +0800
Message-ID: <20221201062526.4089-1-cuigaosheng1@huawei.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 7BIT
Content-Type:   text/plain; charset=US-ASCII
Precedence: bulk

Smatch report warning as follows:

drivers/crypto/img-hash.c:366 img_hash_dma_task() warn: variable
dereferenced before check 'hdev->req'

Variable dereferenced should be done after check 'hdev->req',
fix it.

Fixes: d358f1abbf71 ("crypto: img-hash - Add Imagination Technologies hw hash accelerator")
Fixes: 10badea259fa ("crypto: img-hash - Fix null pointer exception")
Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
---
 drivers/crypto/img-hash.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/crypto/img-hash.c b/drivers/crypto/img-hash.c
index d8e82d69745d..9629e98bd68b 100644
--- a/drivers/crypto/img-hash.c
+++ b/drivers/crypto/img-hash.c
@@ -358,12 +358,16 @@ static int img_hash_dma_init(struct img_hash_dev *hdev)
 static void img_hash_dma_task(unsigned long d)
 {
 	struct img_hash_dev *hdev = (struct img_hash_dev *)d;
-	struct img_hash_request_ctx *ctx = ahash_request_ctx(hdev->req);
+	struct img_hash_request_ctx *ctx;
 	u8 *addr;
 	size_t nbytes, bleft, wsend, len, tbc;
 	struct scatterlist tsg;
 
-	if (!hdev->req || !ctx->sg)
+	if (!hdev->req)
+		return;
+
+	ctx = ahash_request_ctx(hdev->req);
+	if (!ctx->sg)
 		return;
 
 	addr = sg_virt(ctx->sg);
-- 
2.25.1