Re: Qualcomm QCE driver: XTS setkey only allows 128 bit AES

[Herbert Xu <herbert@gondor.apana.org.au>]

Stephan Müller <smueller@chronox.de> wrote:
> Hi,
> 
> The Qualcomm QCE driver implementation defines:
> 
>                .flags          = QCE_ALG_AES | QCE_MODE_XTS,
>                .name           = "xts(aes)",
>                .drv_name       = "xts-aes-qce",
>                .blocksize      = AES_BLOCK_SIZE,
>                .ivsize         = AES_BLOCK_SIZE,
>                .min_keysize    = AES_MIN_KEY_SIZE,
>                .max_keysize    = AES_MAX_KEY_SIZE,
> 
> and
> 
>        alg->cra_ablkcipher.min_keysize = def->min_keysize;
>        alg->cra_ablkcipher.max_keysize = def->max_keysize;
>        alg->cra_ablkcipher.setkey = qce_ablkcipher_setkey;
> 
> Thus, this driver has the limits of 128 to 256 bits for the key. Furthermore, 
> the common setkey function is used.
> 
> May I ask how the key for AES XTS is supposed to be handled here considering 
> that the kernel crypto API expects that the AES key and the tweak key is set 
> via one setkey call. I.e. the setkey should expect 256 through 512 bits.

If the hardware doesn't support it then it needs to be handled with
a fallback.  Shouldn't testmgr catch this though?

Cheers,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
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