crypto: s5p-sss - validate iv before memcpy

This patch adds code to validate "iv" buffer before trying to
memcpy the contents

Signed-off-by: Naveen Krishna Chatradhi <ch.naveen@samsung.com>
Reviewed-by: Tomasz Figa <t.figa@samsung.com>
CC: David S. Miller <davem@davemloft.net>
CC: <linux-samsung-soc@vger.kernel.org>
Acked-by: Vladimir Zapolskiy <vz@mleia.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/s5p-sss.c

@@ -380,7 +380,8 @@ static void s5p_set_aes(struct s5p_aes_dev *dev,
 {
 	void __iomem *keystart;
 
-	memcpy(dev->aes_ioaddr + SSS_REG_AES_IV_DATA(0), iv, 0x10);
+	if (iv)
+		memcpy(dev->aes_ioaddr + SSS_REG_AES_IV_DATA(0), iv, 0x10);
 
 	if (keylen == AES_KEYSIZE_256)
 		keystart = dev->aes_ioaddr + SSS_REG_AES_KEY_DATA(0);