RE: [PATCH v5 4/5] virtio-crypto: adjust dst_len at ops callback

["Gonglei (Arei)" <arei.gonglei@huawei.com>]

> -----Original Message-----
> From: zhenwei pi [mailto:pizhenwei@bytedance.com]
> Sent: Thursday, May 5, 2022 5:24 PM
> To: Gonglei (Arei) <arei.gonglei@huawei.com>; mst@redhat.com
> Cc: jasowang@redhat.com; herbert@gondor.apana.org.au;
> linux-kernel@vger.kernel.org; virtualization@lists.linux-foundation.org;
> linux-crypto@vger.kernel.org; helei.sig11@bytedance.com;
> pizhenwei@bytedance.com; davem@davemloft.net
> Subject: [PATCH v5 4/5] virtio-crypto: adjust dst_len at ops callback
> 
> From: lei he <helei.sig11@bytedance.com>
> 
> For some akcipher operations(eg, decryption of pkcs1pad(rsa)), the length of
> returned result maybe less than akcipher_req->dst_len, we need to recalculate
> the actual dst_len through the virt-queue protocol.
> 
> Cc: Michael S. Tsirkin <mst@redhat.com>
> Cc: Jason Wang <jasowang@redhat.com>
> Cc: Gonglei <arei.gonglei@huawei.com>
> Signed-off-by: lei he <helei.sig11@bytedance.com>
> Signed-off-by: zhenwei pi <pizhenwei@bytedance.com>
> ---
>  drivers/crypto/virtio/virtio_crypto_akcipher_algs.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 

Reviewed-by: Gonglei <arei.gonglei@huawei.com>

Regards,
-Gonglei


> diff --git a/drivers/crypto/virtio/virtio_crypto_akcipher_algs.c
> b/drivers/crypto/virtio/virtio_crypto_akcipher_algs.c
> index 382ccec9ab12..2a60d0525cde 100644
> --- a/drivers/crypto/virtio/virtio_crypto_akcipher_algs.c
> +++ b/drivers/crypto/virtio/virtio_crypto_akcipher_algs.c
> @@ -90,9 +90,12 @@ static void
> virtio_crypto_dataq_akcipher_callback(struct virtio_crypto_request *
>  	}
> 
>  	akcipher_req = vc_akcipher_req->akcipher_req;
> -	if (vc_akcipher_req->opcode != VIRTIO_CRYPTO_AKCIPHER_VERIFY)
> +	if (vc_akcipher_req->opcode != VIRTIO_CRYPTO_AKCIPHER_VERIFY) {
> +		/* actuall length maybe less than dst buffer */
> +		akcipher_req->dst_len = len - sizeof(vc_req->status);
>  		sg_copy_from_buffer(akcipher_req->dst,
> sg_nents(akcipher_req->dst),
>  				    vc_akcipher_req->dst_buf, akcipher_req->dst_len);
> +	}
>  	virtio_crypto_akcipher_finalize_req(vc_akcipher_req, akcipher_req,
> error);  }
> 
> --
> 2.20.1