crypto: mxs-dcp - fix source scatterlist length access

commit c5bcb08 upstream.

mxs_dcp_aes_block_crypt() uses sg_dma_len() without mapping the source
scatterlist with dma_map_sg() first. Therefore, sg_dma_len() is invalid
and could return zero or a stale DMA length, causing encryption and
decryption to process the wrong number of bytes when
CONFIG_NEED_SG_DMA_LENGTH=y.

Use the original scatterlist length instead.

Fixes: 15b59e7 ("crypto: mxs - Add Freescale MXS DCP driver")
Cc: stable@vger.kernel.org
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: toblux

drivers/crypto/mxs-dcp.c

@@ -353,7 +353,7 @@ static int mxs_dcp_aes_block_crypt(struct crypto_async_request *arq)
 
 	for_each_sg(req->src, src, sg_nents(req->src), i) {
 		src_buf = sg_virt(src);
-		len = sg_dma_len(src);
+		len = src->length;
 		tlen += len;
 		limit_hit = tlen > req->cryptlen;