[Linux-stm32] [PATCH] crypto: stm32 - Fix empty message checks

[Herbert Xu]

The empty message checks may trigger on non-empty messages split
over an update operation followed by a final operation (where
req->nbytes can/should be set to zero).

Fixes: b56403a25af7 ("crypto: stm32/hash - Support Ux500 hash")
Signed-off-by: Herbert Xu <herbert at gondor.apana.org.au>

diff --git a/drivers/crypto/stm32/stm32-hash.c b/drivers/crypto/stm32/stm32-hash.c
index 7bf805563ac2..acf8bfc8de4b 100644
--- a/drivers/crypto/stm32/stm32-hash.c
+++ b/drivers/crypto/stm32/stm32-hash.c
@@ -148,6 +148,7 @@ struct stm32_hash_request_ctx {
 	int			nents;
 
 	u8			data_type;
+	bool			nonempty;
 
 	u8 buffer[HASH_BUFLEN] __aligned(sizeof(u32));
 
@@ -310,7 +311,7 @@ static void stm32_hash_write_ctrl(struct stm32_hash_dev *hdev, int bufcnt)
 		 * On the Ux500 we need to set a special flag to indicate that
 		 * the message is zero length.
 		 */
-		if (hdev->pdata->ux500 && bufcnt == 0)
+		if (hdev->pdata->ux500 && !rctx->nonempty)
 			reg |= HASH_CR_UX500_EMPTYMSG;
 
 		if (!hdev->polled)
@@ -754,6 +755,7 @@ static int stm32_hash_init(struct ahash_request *req)
 	rctx->total = 0;
 	rctx->offset = 0;
 	rctx->data_type = HASH_DATA_8_BITS;
+	rctx->nonempty = false;
 
 	memset(rctx->buffer, 0, HASH_BUFLEN);
 
@@ -832,7 +834,7 @@ static void stm32_hash_copy_hash(struct ahash_request *req)
 	__be32 *hash = (void *)rctx->digest;
 	unsigned int i, hashsize;
 
-	if (hdev->pdata->broken_emptymsg && !req->nbytes)
+	if (hdev->pdata->broken_emptymsg && !rctx->nonempty)
 		return stm32_hash_emptymsg_fallback(req);
 
 	switch (rctx->flags & HASH_FLAGS_ALGO_MASK) {
@@ -986,6 +988,8 @@ static int stm32_hash_update(struct ahash_request *req)
 {
 	struct stm32_hash_request_ctx *rctx = ahash_request_ctx(req);
 
+	rctx->nonempty = !!req->nbytes;
+
 	if (!req->nbytes || !(rctx->flags & HASH_FLAGS_CPU))
 		return 0;
 
-- 
Email: Herbert Xu <herbert at gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt