On 6 February 2017 at 08:47, Johannes Berg <johannes@xxxxxxxxxxxxxxxx> wrote:
>
>> {
>> u8 d[AES_BLOCK_SIZE], tmp[AES_BLOCK_SIZE];
>> + struct shash_desc *desc;
>> + u8 buf[sizeof(*desc) + crypto_shash_descsize(tfm)]
>> CRYPTO_MINALIGN_ATTR;
I realised we have a more idiomatic SHASH_DESC_ON_STACK for this.
>> size_t i;
>> - const u8 *data[2];
>> - size_t data_len[2], data_elems;
>> +
>> + desc = (struct shash_desc *)buf;
>> + desc->tfm = tfm;
>>
>> + crypto_shash_digest(desc, (u8[AES_BLOCK_SIZE]){},
>> AES_BLOCK_SIZE, d);
>
> That's an interesting expression in there. Can we name it into a real
> variable? :)
>
Sure, if you prefer.
> I'm also slightly worried about stack usage now - do we know none of
> this goes into an sg list eventually?
>
Shashes do not usually use scatterlists: the shash API does not use
them, but uses u8[] arrays and lengths everywhere, and shashes are
explicitly synchronous, which means they are unsuitable for being
exposed on top of a high latency peripheral that uses DMA.
