linux-kernel - Re: [PATCH v2] crypto: virtio - Less function calls in __virtio_crypto_akcipher_do

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Date: Tue, 9 Jan 2024 23:42:41 +0000
From: Justin Stitt <justinstitt@...gle.com>
To: Markus Elfring <Markus.Elfring@....de>
Cc: kernel test robot <lkp@...el.com>, virtualization@...ts.linux.dev,
	linux-crypto@...r.kernel.org, kernel-janitors@...r.kernel.org,
	"David S. Miller" <davem@...emloft.net>,
	Gonglei <arei.gonglei@...wei.com>,
	Herbert Xu <herbert@...dor.apana.org.au>,
	Jason Wang <jasowang@...hat.com>,
	"Michael S. Tsirkin" <mst@...hat.com>,
	Xuan Zhuo <xuanzhuo@...ux.alibaba.com>, llvm@...ts.linux.dev,
	oe-kbuild-all@...ts.linux.dev, netdev@...r.kernel.org,
	LKML <linux-kernel@...r.kernel.org>, cocci@...ia.fr
Subject: Re: [PATCH v2] crypto: virtio - Less function calls in
 __virtio_crypto_akcipher_do_req() after error detection

Hi,

On Tue, Dec 26, 2023 at 11:12:23AM +0100, Markus Elfring wrote:
> From: Markus Elfring <elfring@...rs.sourceforge.net>
> Date: Tue, 26 Dec 2023 11:00:20 +0100
>
> The kfree() function was called in up to two cases by the
> __virtio_crypto_akcipher_do_req() function during error handling
> even if the passed variable contained a null pointer.
> This issue was detected by using the Coccinelle software.

If the script is short and simple would you mind, in the future,
including it below the fold -- this may help others do similar work down
the line -- Or you could also link to a git-managed version like what
Kees has been doing with his __counted_by patches [1].

>
> * Adjust jump targets.
>
> * Delete two initialisations which became unnecessary
>   with this refactoring.
>
> Signed-off-by: Markus Elfring <elfring@...rs.sourceforge.net>
> ---

Nonetheless,

Reviewed-by: Justin Stitt <justinstitt@...gle.com>
>
> v2:
> A typo was fixed for the delimiter of a label.
>
>  drivers/crypto/virtio/virtio_crypto_akcipher_algs.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/crypto/virtio/virtio_crypto_akcipher_algs.c b/drivers/crypto/virtio/virtio_crypto_akcipher_algs.c
> index 2621ff8a9376..057da5bd8d30 100644
> --- a/drivers/crypto/virtio/virtio_crypto_akcipher_algs.c
> +++ b/drivers/crypto/virtio/virtio_crypto_akcipher_algs.c
> @@ -224,11 +224,11 @@ static int __virtio_crypto_akcipher_do_req(struct virtio_crypto_akcipher_request
>  	struct virtio_crypto *vcrypto = ctx->vcrypto;
>  	struct virtio_crypto_op_data_req *req_data = vc_req->req_data;
>  	struct scatterlist *sgs[4], outhdr_sg, inhdr_sg, srcdata_sg, dstdata_sg;
> -	void *src_buf = NULL, *dst_buf = NULL;
> +	void *src_buf, *dst_buf = NULL;
>  	unsigned int num_out = 0, num_in = 0;
>  	int node = dev_to_node(&vcrypto->vdev->dev);
>  	unsigned long flags;
> -	int ret = -ENOMEM;
> +	int ret;
>  	bool verify = vc_akcipher_req->opcode == VIRTIO_CRYPTO_AKCIPHER_VERIFY;
>  	unsigned int src_len = verify ? req->src_len + req->dst_len : req->src_len;
>
> @@ -239,7 +239,7 @@ static int __virtio_crypto_akcipher_do_req(struct virtio_crypto_akcipher_request
>  	/* src data */
>  	src_buf = kcalloc_node(src_len, 1, GFP_KERNEL, node);
>  	if (!src_buf)
> -		goto err;
> +		return -ENOMEM;
>
>  	if (verify) {
>  		/* for verify operation, both src and dst data work as OUT direction */
> @@ -254,7 +254,7 @@ static int __virtio_crypto_akcipher_do_req(struct virtio_crypto_akcipher_request
>  		/* dst data */
>  		dst_buf = kcalloc_node(req->dst_len, 1, GFP_KERNEL, node);
>  		if (!dst_buf)
> -			goto err;
> +			goto free_src;
>
>  		sg_init_one(&dstdata_sg, dst_buf, req->dst_len);
>  		sgs[num_out + num_in++] = &dstdata_sg;
> @@ -277,9 +277,9 @@ static int __virtio_crypto_akcipher_do_req(struct virtio_crypto_akcipher_request
>  	return 0;
>
>  err:
> -	kfree(src_buf);
>  	kfree(dst_buf);
> -
> +free_src:
> +	kfree(src_buf);
>  	return -ENOMEM;
>  }
>
> --
> 2.43.0
>

[1]: https://lore.kernel.org/all/20230922175023.work.239-kees@kernel.org/

Thanks
Justin