Re: [PATCH] crypto: mxs-dcp - fix source scatterlist length access

[Frank Li]

>
> 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.

It'd beter add some description about copy sg to a bounce buffer to do
descrytpion, needn't map sg firstly and direct use the original
scatterlist length.

Reviewed-by: Frank Li <Frank.Li@xxxxxxx>
>
> Fixes: 15b59e7c3733 ("crypto: mxs - Add Freescale MXS DCP driver")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Thorsten Blum <thorsten.blum@xxxxxxxxx>
> ---
>  drivers/crypto/mxs-dcp.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/crypto/mxs-dcp.c b/drivers/crypto/mxs-dcp.c
> index 133ebc998236..595b2fd84667 100644
> --- a/drivers/crypto/mxs-dcp.c
> +++ b/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;
>
>