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From:   Nikita Zhandarovich <n.zhandarovich@fintech.ru>
To:     Antoine Tenart <atenart@kernel.org>
CC:     Nikita Zhandarovich <n.zhandarovich@fintech.ru>,
        "David S. Miller" <davem@davemloft.net>,
        <linux-crypto@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: [PATCH v2] crypto: safexcel - Add error handling for dma_map_sg() calls
Date:   Fri, 1 Dec 2023 04:49:29 -0800
Message-ID: <20231201124929.12448-1-n.zhandarovich@fintech.ru>
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Macro dma_map_sg() may return 0 on error. This patch enables
checks in case of the macro failure and ensures unmapping of
previously mapped buffers with dma_unmap_sg().

Found by Linux Verification Center (linuxtesting.org) with static
analysis tool SVACE.

Fixes: 49186a7d9e46 ("crypto: inside_secure - Avoid dma map if size is zero")
Signed-off-by: Nikita Zhandarovich <n.zhandarovich@fintech.ru>
---
v2: remove extra level of parentheses and
change return error code from -ENOMEM to EIO
per Antoine Tenart's <atenart@kernel.org> suggestion

 drivers/crypto/inside-secure/safexcel_cipher.c | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/drivers/crypto/inside-secure/safexcel_cipher.c b/drivers/crypto/inside-secure/safexcel_cipher.c
index 272c28b5a088..b83818634ae4 100644
--- a/drivers/crypto/inside-secure/safexcel_cipher.c
+++ b/drivers/crypto/inside-secure/safexcel_cipher.c
@@ -742,9 +742,9 @@ static int safexcel_send_req(struct crypto_async_request *base, int ring,
 				max(totlen_src, totlen_dst));
 			return -EINVAL;
 		}
-		if (sreq->nr_src > 0)
-			dma_map_sg(priv->dev, src, sreq->nr_src,
-				   DMA_BIDIRECTIONAL);
+		if (sreq->nr_src > 0 &&
+		    !dma_map_sg(priv->dev, src, sreq->nr_src, DMA_BIDIRECTIONAL))
+			return -EIO;
 	} else {
 		if (unlikely(totlen_src && (sreq->nr_src <= 0))) {
 			dev_err(priv->dev, "Source buffer not large enough (need %d bytes)!",
@@ -752,8 +752,9 @@ static int safexcel_send_req(struct crypto_async_request *base, int ring,
 			return -EINVAL;
 		}
 
-		if (sreq->nr_src > 0)
-			dma_map_sg(priv->dev, src, sreq->nr_src, DMA_TO_DEVICE);
+		if (sreq->nr_src > 0 &&
+		    !dma_map_sg(priv->dev, src, sreq->nr_src, DMA_TO_DEVICE))
+			return -EIO;
 
 		if (unlikely(totlen_dst && (sreq->nr_dst <= 0))) {
 			dev_err(priv->dev, "Dest buffer not large enough (need %d bytes)!",
@@ -762,9 +763,11 @@ static int safexcel_send_req(struct crypto_async_request *base, int ring,
 			goto unmap;
 		}
 
-		if (sreq->nr_dst > 0)
-			dma_map_sg(priv->dev, dst, sreq->nr_dst,
-				   DMA_FROM_DEVICE);
+		if (sreq->nr_dst > 0 &&
+		    !dma_map_sg(priv->dev, dst, sreq->nr_dst, DMA_FROM_DEVICE)) {
+			ret = -EIO;
+			goto unmap;
+		}
 	}
 
 	memcpy(ctx->base.ctxr->data, ctx->key, ctx->key_len);