crypto: caam - Clear some memory in instantiate_rng

[ Upstream commit 9c19fb8 ]

According to the comment at the end of the 'for' loop just a few lines
below, it looks needed to clear 'desc'.

So it should also be cleared for the first iteration.

Move the memset() to the beginning of the loop to be safe.

Fixes: 281922a ("crypto: caam - add support for SEC v5.x RNG4")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Gaurav Jain <gaurav.jain@nxp.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/crypto/caam/ctrl.c

@@ -284,6 +284,10 @@ static int instantiate_rng(struct device *ctrldev, int state_handle_mask,
 		const u32 rdsta_if = RDSTA_IF0 << sh_idx;
 		const u32 rdsta_pr = RDSTA_PR0 << sh_idx;
 		const u32 rdsta_mask = rdsta_if | rdsta_pr;
+
+		/* Clear the contents before using the descriptor */
+		memset(desc, 0x00, CAAM_CMD_SZ * 7);
+
 		/*
 		 * If the corresponding bit is set, this state handle
 		 * was initialized by somebody else, so it's left alone.
@@ -327,8 +331,6 @@ static int instantiate_rng(struct device *ctrldev, int state_handle_mask,
 		}
 
 		dev_info(ctrldev, "Instantiated RNG4 SH%d\n", sh_idx);
-		/* Clear the contents before recreating the descriptor */
-		memset(desc, 0x00, CAAM_CMD_SZ * 7);
 	}
 
 	kfree(desc);