Re: [PATCH v3 06/10] certs: Make blacklist_vet_description() more strict

Mickaël Salaün
2021-01-20T12:00:13Z

On 20/01/2021 05:16, Jarkko Sakkinen wrote:
> On Thu, Jan 14, 2021 at 04:19:05PM +0100, Mickaël Salaün wrote:
>> From: Mickaël Salaün <mic@linux.microsoft.com>
>>
>> Before exposing this new key type to user space, make sure that only
>> meaningful blacklisted hashes are accepted. This is also checked for
>> builtin blacklisted hashes, but a following commit make sure that the
>> user will notice (at built time) and will fix the configuration if it
>> already included errors.
>>
>> Check that a blacklist key description starts with a valid prefix and
>> then a valid hexadecimal string.
>>
>> Cc: David Howells <dhowells@redhat.com>
>> Cc: David Woodhouse <dwmw2@infradead.org>
>> Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com>
>> Acked-by: Jarkko Sakkinen <jarkko@kernel.org>
>
> In this I'm not as worried about ABI, i.e. you don't have any reason
> supply any other data, which doesn't follow these ruels, whereas there
> could very well be a script that does format hex "incorrectly".

I think I answered this comment in patch 2/10: there is no ABI breakage,
it only prepares for safe dynamic key addition. Patch 10/10 enables to
avoid using incorrect/useless/mis-leading hashes and force users to fix
these hashes (that were not taken into account)

>
> /Jarkko
>