Re: [PATCH v5 05/11] crypto: qce: skcipher: Return error for zero length messages

[Eric Biggers <ebiggers@kernel.org>]

On Thu, Feb 04, 2021 at 04:43:53PM -0500, Thara Gopinath wrote:
> Crypto engine BAM dma does not support 0 length data. Return unsupported
> if zero length messages are passed for transformation.
> 
> Signed-off-by: Thara Gopinath <thara.gopinath@linaro.org>
> ---
>  drivers/crypto/qce/skcipher.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/crypto/qce/skcipher.c b/drivers/crypto/qce/skcipher.c
> index de1f37ed4ee6..331b3c3a5b59 100644
> --- a/drivers/crypto/qce/skcipher.c
> +++ b/drivers/crypto/qce/skcipher.c
> @@ -8,6 +8,7 @@
>  #include <linux/interrupt.h>
>  #include <linux/moduleparam.h>
>  #include <linux/types.h>
> +#include <linux/errno.h>
>  #include <crypto/aes.h>
>  #include <crypto/internal/des.h>
>  #include <crypto/internal/skcipher.h>
> @@ -260,6 +261,10 @@ static int qce_skcipher_crypt(struct skcipher_request *req, int encrypt)
>  	rctx->flags |= encrypt ? QCE_ENCRYPT : QCE_DECRYPT;
>  	keylen = IS_XTS(rctx->flags) ? ctx->enc_keylen >> 1 : ctx->enc_keylen;
>  
> +	/* CE does not handle 0 length messages */
> +	if (!req->cryptlen)
> +		return -EOPNOTSUPP;
> +

For the algorithms in question, the correct behavior is to return 0.

Aren't the tests catching that difference?

- Eric