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

Eric Snowberg
2021-02-08T23:07:05Z

> On Feb 6, 2021, at 11:30 AM, Mickaël Salaün <mic@digikod.net> wrote:
>
> On 06/02/2021 02:14, Eric Snowberg wrote:
>
>> I have done some additional testing, I am seeing a regression. The blacklist
>> keyring is no longer picking up any of the hashes from the dbx during boot.
>> I backed out the merge with my changes (fdbbe7ceeb95090d09c33ce0497e0394c82aa33d)
>> and still see the regression. I then backed out Mickaël merge
>> (5bf1adccf5c41dbdd51d1f4de220d335d9548598) and it fixes the regression.
>>
>> On a x86 with the updated dbx from uefi.org, I’d expect to see 234 bin hash entries
>> in the blacklist keyring. With the current merged code, there is none.
>
> Hum, I missed a part in refactoring (commit
> f78e50c8f750c0ac6767ac1ed006360cf77c56c4). :/
> Could you please test the following patch?
>
> diff --git a/certs/blacklist.c b/certs/blacklist.c
> index 07c592ae5307..f998a2e85ddc 100644
> --- a/certs/blacklist.c
> +++ b/certs/blacklist.c
> @@ -197,13 +197,16 @@ int mark_hash_blacklisted(const u8 *hash, size_t
> hash_len,
> enum blacklist_hash_type hash_type)
> {
> const char *buffer;
> + int err;
>
> buffer = get_raw_hash(hash, hash_len, hash_type);
> if (IS_ERR(buffer))
> return PTR_ERR(buffer);
> + err = mark_raw_hash_blacklisted(buffer);
> kfree(buffer);
> - return 0;
> + return err;
> }

I applied this patch, it works better, but there is still a regression.
Most of the hashes show up in the blacklist keyring now. However some
do not, here is what I see in the log during boot:

[ 2.321876] blacklist: Problem blacklisting hash (-13)
[ 2.322729] blacklist: Problem blacklisting hash (-13)
[ 2.323549] blacklist: Problem blacklisting hash (-13)
[ 2.324369] blacklist: Problem blacklisting hash (-13)

> Is it possible to test these kind of dbx blacklist with Qemu?

Yes, just use OVMF.