[PATCH] crypto: atmel-tdes - use scatterlist length before DMA mapping

[Herbert Xu]

On Sun, May 31, 2026 at 10:41:17PM +0200, Thorsten Blum wrote:
> Using sg_dma_len() is only valid after mapping the scatterlist with
> dma_map_sg(). However, atmel_tdes_crypt_start() uses it before mapping
> to compare input/output lengths and to compute the transfer count.
> 
> Use the original scatterlist lengths before DMA mapping to avoid reading
> stale or uninitialized DMA lengths when CONFIG_NEED_SG_DMA_LENGTH=y.
> 
> Fixes: 13802005d8f2 ("crypto: atmel - add Atmel DES/TDES driver")
> Fixes: 1f858040c2f7 ("crypto: atmel-tdes - add support for latest release of the IP (0x700)")
> Cc: stable at vger.kernel.org
> Signed-off-by: Thorsten Blum <thorsten.blum at linux.dev>
> ---
>  drivers/crypto/atmel-tdes.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/crypto/atmel-tdes.c b/drivers/crypto/atmel-tdes.c
> index 643e507f9c02..0d62b24e9fc7 100644
> --- a/drivers/crypto/atmel-tdes.c
> +++ b/drivers/crypto/atmel-tdes.c
> @@ -463,14 +463,14 @@ static int atmel_tdes_crypt_start(struct atmel_tdes_dev *dd)
>  			IS_ALIGNED(dd->out_sg->length, dd->ctx->block_size);
>  		fast = in && out;
>  
> -		if (sg_dma_len(dd->in_sg) != sg_dma_len(dd->out_sg))
> +		if (dd->in_sg->length != dd->out_sg->length)
>  			fast = 0;
>  	}
>  
>  
>  	if (fast)  {
> -		count = min_t(size_t, dd->total, sg_dma_len(dd->in_sg));
> -		count = min_t(size_t, count, sg_dma_len(dd->out_sg));
> +		count = min_t(size_t, dd->total, dd->in_sg->length);
> +		count = min_t(size_t, count, dd->out_sg->length);

If fast == 1, then dd->in_sg->length must be equal to dd->out_sg->length,
so the second line is redundant.

Cheers,
-- 
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