linux-kernel - Re: [PATCH v6 3/6] crypto: AF_ALG -- add asymmetric cipher interface

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Date:	Tue, 14 Jun 2016 10:22:15 -0700 (PDT)
From:	Mat Martineau <mathew.j.martineau@...ux.intel.com>
To:	smueller@...onox.de
cc:	Tadeusz Struk <tadeusz.struk@...el.com>, dhowells@...hat.com,
	herbert@...dor.apana.org.au, linux-api@...r.kernel.org,
	marcel@...tmann.org, linux-kernel@...r.kernel.org,
	keyrings@...r.kernel.org, linux-crypto@...r.kernel.org,
	dwmw2@...radead.org, davem@...emloft.net
Subject: Re: [PATCH v6 3/6] crypto: AF_ALG -- add asymmetric cipher
 interface


Stephan,

On Sat, 14 May 2016, Tadeusz Struk wrote:

> From: Stephan Mueller <smueller@...onox.de>
>
> This patch adds the user space interface for asymmetric ciphers. The
> interface allows the use of sendmsg as well as vmsplice to provide data.
>
> This version has been rebased on top of 4.6 and a few chackpatch issues
> have been fixed.
>
> Signed-off-by: Stephan Mueller <smueller@...onox.de>
> Signed-off-by: Tadeusz Struk <tadeusz.struk@...el.com>
> ---
> crypto/algif_akcipher.c |  542 +++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 542 insertions(+)
> create mode 100644 crypto/algif_akcipher.c
>
> diff --git a/crypto/algif_akcipher.c b/crypto/algif_akcipher.c
> new file mode 100644
> index 0000000..6342b6e
> --- /dev/null
> +++ b/crypto/algif_akcipher.c
> +
> +static int akcipher_sendmsg(struct socket *sock, struct msghdr *msg,
> +			    size_t size)
> +{
> +	struct sock *sk = sock->sk;
> +	struct alg_sock *ask = alg_sk(sk);
> +	struct akcipher_ctx *ctx = ask->private;
> +	struct akcipher_sg_list *sgl = &ctx->tsgl;
> +	struct af_alg_control con = {};
> +	long copied = 0;
> +	int op = 0;
> +	bool init = 0;
> +	int err;
> +
> +	if (msg->msg_controllen) {
> +		err = af_alg_cmsg_send(msg, &con);
> +		if (err)
> +			return err;
> +
> +		init = 1;
> +		switch (con.op) {
> +		case ALG_OP_VERIFY:
> +		case ALG_OP_SIGN:
> +		case ALG_OP_ENCRYPT:
> +		case ALG_OP_DECRYPT:
> +			op = con.op;
> +			break;
> +		default:
> +			return -EINVAL;
> +		}
> +	}
> +
> +	lock_sock(sk);
> +	if (!ctx->more && ctx->used)
> +		goto unlock;

err might be uninitialised at this goto. Should it be set to something 
like -EALREADY to indicate that data is already queued for a different 
crypto op?

<snip>

> +unlock:
> +	akcipher_data_wakeup(sk);
> +	release_sock(sk);
> +
> +	return err ?: copied;
> +}

Regards,

--
Mat Martineau
Intel OTC