On Thu, Dec 04, 2025 at 07:25:02PM +0800, Bibo Mao wrote:
> Add IV buffer in structure virtio_crypto_sym_request to avoid unnecessary
> IV buffer allocation in encrypt/decrypt process. And IV buffer is cleared
> when encrypt/decrypt is finished.
>
> Signed-off-by: Bibo Mao <[email protected]>
> ---
> .../virtio/virtio_crypto_skcipher_algs.c | 20 +++++++------------
> 1 file changed, 7 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/crypto/virtio/virtio_crypto_skcipher_algs.c
> b/drivers/crypto/virtio/virtio_crypto_skcipher_algs.c
> index a7c7c726e6d9..c911b7ba8f13 100644
> --- a/drivers/crypto/virtio/virtio_crypto_skcipher_algs.c
> +++ b/drivers/crypto/virtio/virtio_crypto_skcipher_algs.c
> @@ -30,9 +30,9 @@ struct virtio_crypto_sym_request {
>
> /* Cipher or aead */
> uint32_t type;
> - uint8_t *iv;
> /* Encryption? */
> bool encrypt;
> + uint8_t iv[0];
> };
>
> struct virtio_crypto_algo {
> @@ -402,12 +402,7 @@ __virtio_crypto_skcipher_do_req(struct
> virtio_crypto_sym_request *vc_sym_req,
> * Avoid to do DMA from the stack, switch to using
> * dynamically-allocated for the IV
> */
> - iv = kzalloc_node(ivsize, GFP_ATOMIC,
> - dev_to_node(&vcrypto->vdev->dev));
> - if (!iv) {
> - err = -ENOMEM;
> - goto free;
> - }
> + iv = vc_sym_req->iv;
> memcpy(iv, req->iv, ivsize);
> if (!vc_sym_req->encrypt)
> scatterwalk_map_and_copy(req->iv, req->src,
> @@ -416,7 +411,6 @@ __virtio_crypto_skcipher_do_req(struct
> virtio_crypto_sym_request *vc_sym_req,
>
> sg_init_one(&iv_sg, iv, ivsize);
> sgs[num_out++] = &iv_sg;
> - vc_sym_req->iv = iv;
>
> /* Source data */
> for (sg = req->src; src_nents; sg = sg_next(sg), src_nents--)
> @@ -438,12 +432,10 @@ __virtio_crypto_skcipher_do_req(struct
> virtio_crypto_sym_request *vc_sym_req,
> virtqueue_kick(data_vq->vq);
> spin_unlock_irqrestore(&data_vq->lock, flags);
> if (unlikely(err < 0))
> - goto free_iv;
> + goto free;
>
> return 0;
>
> -free_iv:
> - kfree_sensitive(iv);
so iv is no longer cleared on error. problem?
> free:
> kfree(sgs);
> return err;
> @@ -501,8 +493,10 @@ static int virtio_crypto_skcipher_init(struct
> crypto_skcipher *tfm)
> {
> struct virtio_crypto_skcipher_ctx *ctx = crypto_skcipher_ctx(tfm);
> struct skcipher_alg *alg = crypto_skcipher_alg(tfm);
> + int size;
>
> - crypto_skcipher_set_reqsize(tfm, sizeof(struct
> virtio_crypto_sym_request));
> + size = sizeof(struct virtio_crypto_sym_request) +
> crypto_skcipher_ivsize(tfm);
> + crypto_skcipher_set_reqsize(tfm, size);
> ctx->alg = container_of(alg, struct virtio_crypto_algo, algo.base);
>
> return 0;
> @@ -552,7 +546,7 @@ static void virtio_crypto_skcipher_finalize_req(
> scatterwalk_map_and_copy(req->iv, req->dst,
> req->cryptlen - ivsize,
> ivsize, 0);
> - kfree_sensitive(vc_sym_req->iv);
> + memzero_explicit(vc_sym_req->iv, ivsize);
> virtcrypto_clear_request(&vc_sym_req->base);
>
> crypto_finalize_skcipher_request(vc_sym_req->base.dataq->engine,
> --
> 2.39.3
