Re: [PATCH 5/11] [CRYPTO] chainiv: Add chain IV generator

[Evgeniy Polyakov <johnpol@2ka.mipt.ru>]

On Thu, Nov 22, 2007 at 04:48:43PM +0800, Herbert Xu (herbert@gondor.apana.org.au) wrote:
> +static int chainiv_givcrypt(struct ablkcipher_request *req)
> +{
> +	struct crypto_ablkcipher *geniv = crypto_ablkcipher_reqtfm(req);
> +	struct chainiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
> +	struct ablkcipher_request *subreq = ablkcipher_request_ctx(req);
> +	unsigned int ivsize;
> +	int err;
> +
> +	ablkcipher_request_set_tfm(subreq, ctx->cipher);
> +	ablkcipher_request_set_callback(subreq, req->base.flags &
> +						~CRYPTO_TFM_REQ_MAY_SLEEP,
> +					req->base.complete, req->base.data);
> +	ablkcipher_request_set_crypt(subreq, req->src, req->dst, req->nbytes,
> +				     req->info);
> +
> +	spin_lock_bh(&ctx->lock);

Crypto hardware can access iv in interrupt context and thus this can get
wrong data.

> +	ivsize = crypto_ablkcipher_ivsize(geniv);
> +
> +	memcpy(req->giv, ctx->iv, ivsize);
> +	memcpy(req->info, ctx->iv, ivsize);
> +
> +	err = crypto_ablkcipher_encrypt(subreq);
> +	if (err)
> +		goto unlock;

Are you sure that crypto operation has to be limited to be performed
with turned off bottom halves? I believe this is a huge limitation for
those ablkcipher devices which are not async actually...

-- 
	Evgeniy Polyakov