linux-kernel - Re: [PATCH v4 3/3] crypto: Add Allwinner Security System crypto accelerator

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Date:	Thu, 24 Jul 2014 13:04:55 +0200
From:	Corentin LABBE <clabbe.montjoie@...il.com>
To:	Herbert Xu <herbert@...dor.apana.org.au>
CC:	robh+dt@...nel.org, pawel.moll@....com, mark.rutland@....com,
	ijc+devicetree@...lion.org.uk, galak@...eaurora.org,
	rdunlap@...radead.org, maxime.ripard@...e-electrons.com,
	linux@....linux.org.uk, davem@...emloft.net,
	grant.likely@...aro.org, devicetree@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	linux-crypto@...r.kernel.org
Subject: Re: [PATCH v4 3/3] crypto: Add Allwinner Security System crypto accelerator

Le 24/07/2014 08:00, Herbert Xu a écrit :
> On Sat, Jul 12, 2014 at 02:59:13PM +0200, LABBE Corentin wrote:
>>
>> +/* sunxi_hash_init: initialize request context
>> + * Activate the SS, and configure it for MD5 or SHA1
>> + */
>> +int sunxi_hash_init(struct ahash_request *areq)
>> +{
>> +	const char *hash_type;
>> +	struct crypto_ahash *tfm = crypto_ahash_reqtfm(areq);
>> +	struct sunxi_req_ctx *op = crypto_ahash_ctx(tfm);
>> +
>> +	mutex_lock(&ss->lock);
>> +
>> +	hash_type = crypto_tfm_alg_name(areq->base.tfm);
>> +
>> +	op->byte_count = 0;
>> +	op->nbwait = 0;
>> +	op->waitbuf = 0;
>> +
>> +	/* Enable and configure SS for MD5 or SHA1 */
>> +	if (strcmp(hash_type, "sha1") == 0)
>> +		op->mode = SS_OP_SHA1;
>> +	else
>> +		op->mode = SS_OP_MD5;
>> +
>> +	writel(op->mode | SS_ENABLED, ss->base + SS_CTL);
>> +	return 0;
> 
> The hash driver is completely broken.  You are modifying tfm
> ctx data which is shared by all users of a single tfm.  So
> if two users conduct hashes in parallel they will step all
> over each other.

So where can I store data for each request ?

> 
> Worse, the unpaired mutex_lock will quickly lead to dead locks.
> 
> You cannot assume that final will be called.

An user reported an equivalent problem when using openssl speed test with cryptodev.
Does cryptoqueue is a good answer to that problem since the device could handle only one transformation at a time ?
And perhaps with cryptoqueue,  my first question is useless.
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