Re: Conflict with Mickaël Salaün's blacklist patches [was [PATCH v5 0/4] Add EFI_CERT_X509_GUID support for dbx/mokx entries]

From: Eric Snowberg
Date: Thu Feb 04 2021 - 19:26:15 EST



> On Feb 4, 2021, at 1:26 AM, Mickaël Salaün <mic@xxxxxxxxxxx> wrote:
>
>
> On 04/02/2021 04:53, Eric Snowberg wrote:
>>
>>> On Feb 3, 2021, at 11:49 AM, Mickaël Salaün <mic@xxxxxxxxxxx> wrote:
>>>
>>> This looks good to me, and it still works for my use case. Eric's
>>> patchset only looks for asymmetric keys in the blacklist keyring, so
>>> even if we use the same keyring we don't look for the same key types. My
>>> patchset only allows blacklist keys (i.e. hashes, not asymmetric keys)
>>> to be added by user space (if authenticated), but because Eric's
>>> asymmetric keys are loaded with KEY_ALLOC_BYPASS_RESTRICTION, it should
>>> be OK for his use case. There should be no interference between the two
>>> new features, but I find it a bit confusing to have such distinct use of
>>> keys from the same keyring depending on their type.
>>
>> I agree, it is a bit confusing. What is the thought of having a dbx
>> keyring, similar to how the platform keyring works?
>>
>> https://www.spinics.net/lists/linux-security-module/msg40262.html
>>
>>
>>> On 03/02/2021 17:26, David Howells wrote:
>>>>
>>>> Eric Snowberg <eric.snowberg@xxxxxxxxxx> wrote:
>>>>
>>>>> This is the fifth patch series for adding support for
>>>>> EFI_CERT_X509_GUID entries [1]. It has been expanded to not only include
>>>>> dbx entries but also entries in the mokx. Additionally my series to
>>>>> preload these certificate [2] has also been included.
>>>>
>>>> Okay, I've tentatively applied this to my keys-next branch. However, it
>>>> conflicts minorly with Mickaël Salaün's patches that I've previously merged on
>>>> the same branch. Can you have a look at the merge commit
>>>>
>>>> https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git/commit/?h=keys-next&id=fdbbe7ceeb95090d09c33ce0497e0394c82aa33d
>>>>
>>>> (the top patch of my keys-next branch)
>>>>
>>>> to see if that is okay by both of you? If so, can you give it a whirl?
>>
>>
>> I’m seeing a build error within blacklist_hashes_checked with
>> one of my configs.
>>
>> The config is as follows:
>>
>> $ grep CONFIG_SYSTEM_BLACKLIST_HASH_LIST .config
>> CONFIG_SYSTEM_BLACKLIST_HASH_LIST=“revocation_list"
>>
>> $ cat certs/revocation_list
>> "tbs:1e125ea4f38acb7b29b0c495fd8e7602c2c3353b913811a9da3a2fb505c08a32”
>>
>> make[1]: *** No rule to make target 'revocation_list', needed by 'certs/blacklist_hashes_checked'. Stop.
>
> It requires an absolute path.

Ok, if I use an absolute path now with CONFIG_SYSTEM_BLACKLIST_HASH_LIST
it works.

> This is to align with other variables
> using the config_filename macro: CONFIG_SYSTEM_TRUSTED_KEYS,
> CONFIG_MODULE_SIG_KEY and now CONFIG_SYSTEM_REVOCATION_KEYS.

I just did a quick test with CONFIG_SYSTEM_TRUSTED_KEYS. It looks like we
can use either a relative or absolute path with CONFIG_SYSTEM_TRUSTED_KEYS.
Shouldn’t this be consistent?

> Cf. https://lore.kernel.org/lkml/1221725.1607515111@xxxxxxxxxxxxxxxxxxxxxx/
>
> We may want to patch scripts/kconfig/streamline_config.pl for both
> CONFIG_SYSTEM_REVOCATION_KEYS and CONFIG_SYSTEM_BLACKLIST_HASH_LIST, to
> warn user (and exit with an error) if such files are not found.