linux-kernel - [PATCH v2 5/9] crypto: inside-secure - do not access buffers mapped to the device

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Message-Id: <20180319082121.32103-6-antoine.tenart@bootlin.com>
Date:   Mon, 19 Mar 2018 09:21:17 +0100
From:   Antoine Tenart <antoine.tenart@...tlin.com>
To:     herbert@...dor.apana.org.au, davem@...emloft.net
Cc:     Antoine Tenart <antoine.tenart@...tlin.com>,
        linux-crypto@...r.kernel.org, linux-kernel@...r.kernel.org,
        thomas.petazzoni@...tlin.com, maxime.chevallier@...tlin.com,
        gregory.clement@...tlin.com, miquel.raynal@...tlin.com,
        nadavh@...vell.com, oferh@...vell.com, igall@...vell.com
Subject: [PATCH v2 5/9] crypto: inside-secure - do not access buffers mapped to the device

This patches update the way the digest is copied from the state buffer
to the result buffer, so that the copy only happen after the state
buffer was DMA unmapped, as otherwise the buffer would be owned by the
device.

Signed-off-by: Antoine Tenart <antoine.tenart@...tlin.com>
---
 drivers/crypto/inside-secure/safexcel_hash.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/crypto/inside-secure/safexcel_hash.c b/drivers/crypto/inside-secure/safexcel_hash.c
index ef3e0c1c0f2c..b9ec82f3dee1 100644
--- a/drivers/crypto/inside-secure/safexcel_hash.c
+++ b/drivers/crypto/inside-secure/safexcel_hash.c
@@ -156,10 +156,6 @@ static int safexcel_handle_req_result(struct safexcel_crypto_priv *priv, int rin
 	safexcel_complete(priv, ring);
 	spin_unlock_bh(&priv->ring[ring].egress_lock);
 
-	if (sreq->finish)
-		memcpy(areq->result, sreq->state,
-		       crypto_ahash_digestsize(ahash));
-
 	if (sreq->nents) {
 		dma_unmap_sg(priv->dev, areq->src, sreq->nents, DMA_TO_DEVICE);
 		sreq->nents = 0;
@@ -177,6 +173,10 @@ static int safexcel_handle_req_result(struct safexcel_crypto_priv *priv, int rin
 		sreq->cache_dma = 0;
 	}
 
+	if (sreq->finish)
+		memcpy(areq->result, sreq->state,
+		       crypto_ahash_digestsize(ahash));
+
 	cache_len = sreq->len - sreq->processed;
 	if (cache_len)
 		memcpy(sreq->cache, sreq->cache_next, cache_len);
-- 
2.14.3