Re: [PATCH v6 6/8] fscrypt: move all the shared mode key setup deeper

[Josef Bacik <josef@toxicpanda.com>]

On Tue, Aug 08, 2023 at 01:08:06PM -0400, Sweet Tea Dorminy wrote:
> Currently, fscrypt_setup_v2_file_key() has a set of ifs which encode
> various information about how to set up a new mode key if necessary for
> a shared-key policy (DIRECT or IV_INO_LBLK_*). This is somewhat awkward
> -- this information is only needed at the point that we need to setup a
> new key, which is not the common case; the setup details are recorded as
> function parameters relatively far from where they're actually used; and
> at the point we use the parameters, we can derive the information
> equally well.
> 
> So this moves mode and policy checking as deep into the callstack as
> possible. mk_prepared_key_for_mode_policy() deals with the array lookup
> within a master key. And fill_hkdf_info_for mode_key() deals with
> filling in the hkdf info as necessary for a particular policy. These
> seem a little clearer in broad strokes, emphasizing the similarities
> between the policies, but it does spread out the information on how the
> key is derived for a particular policy more.
> 
> Signed-off-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>

Reviewed-by: Josef Bacik <josef@toxicpanda.com>

Thanks,

Josef