Re: [RFC v2 1/7] integrity: added digest calculation function

[Rusty Russell]

On Wed, 15 Aug 2012 21:43:06 +0300, Dmitry Kasatkin <dmitry.kasatkin@xxxxxxxxx> wrote:
> +	} else {
> +		struct {
> +			struct shash_desc shash;
> +			char ctx[crypto_shash_descsize(tfm)];
> +		} desc;

Linus had a rant a while ago about using variable-sized stack vars in
the kernel (can't find a reference right now, sorry).

The problem is that either you know there's a limit to
crypto_shash_descsize(), in which case you can just use this here, or
you don't know, in which case, this risks a stack oveflow.

Cheers,
Rusty.
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