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SubjectRe: [PATCH 4/4] integrity: Load mokx variables into the blacklist keyring
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> On Mar 12, 2021, at 11:39 AM, Dimitri John Ledkov <dimitri.ledkov@canonical.com> wrote:
>
> On 25/02/2021 20:59, David Howells wrote:
>> From: Eric Snowberg <eric.snowberg@oracle.com>
>>
>> During boot the Secure Boot Forbidden Signature Database, dbx,
>> is loaded into the blacklist keyring. Systems booted with shim
>> have an equivalent Forbidden Signature Database called mokx.
>> Currently mokx is only used by shim and grub, the contents are
>> ignored by the kernel.
>>
>> Add the ability to load mokx into the blacklist keyring during boot.
>>
>> Signed-off-by: Eric Snowberg <eric.snowberg@oracle.com>
>> Suggested-by: James Bottomley <James.Bottomley@HansenPartnership.com>
>> Signed-off-by: David Howells <dhowells@redhat.com>
>> cc: Jarkko Sakkinen <jarkko@kernel.org>
>> Link: https://lore.kernel.org/r/20210122181054.32635-5-eric.snowberg@oracle.com/ # v5
>> Link: https://lore.kernel.org/r/c33c8e3839a41e9654f41cc92c7231104931b1d7.camel@HansenPartnership.com/
>> ---
>>
>> security/integrity/platform_certs/load_uefi.c | 20 ++++++++++++++++++--
>> 1 file changed, 18 insertions(+), 2 deletions(-)
>>
>> diff --git a/security/integrity/platform_certs/load_uefi.c b/security/integrity/platform_certs/load_uefi.c
>> index ee4b4c666854..f290f78c3f30 100644
>> --- a/security/integrity/platform_certs/load_uefi.c
>> +++ b/security/integrity/platform_certs/load_uefi.c
>> @@ -132,8 +132,9 @@ static int __init load_moklist_certs(void)
>> static int __init load_uefi_certs(void)
>> {
>> efi_guid_t secure_var = EFI_IMAGE_SECURITY_DATABASE_GUID;
>> - void *db = NULL, *dbx = NULL;
>> - unsigned long dbsize = 0, dbxsize = 0;
>> + efi_guid_t mok_var = EFI_SHIM_LOCK_GUID;
>> + void *db = NULL, *dbx = NULL, *mokx = NULL;
>> + unsigned long dbsize = 0, dbxsize = 0, mokxsize = 0;
>> efi_status_t status;
>> int rc = 0;
>>
>> @@ -175,6 +176,21 @@ static int __init load_uefi_certs(void)
>> kfree(dbx);
>> }
>>
>> + mokx = get_cert_list(L"MokListXRT", &mok_var, &mokxsize, &status);
>> + if (!mokx) {
>> + if (status == EFI_NOT_FOUND)
>> + pr_debug("mokx variable wasn't found\n");
>> + else
>> + pr_info("Couldn't get mokx list\n");
>> + } else {
>> + rc = parse_efi_signature_list("UEFI:MokListXRT",
>> + mokx, mokxsize,
>> + get_handler_for_dbx);
>> + if (rc)
>> + pr_err("Couldn't parse mokx signatures %d\n", rc);
>> + kfree(mokx);
>> + }
>> +
>
>
> My preference would be if the above hunk was moved into the
> load_moklist_certs() function which is called just below. Such that
> loading of MokListRT & MOkListXRT are done next to each other.
>
> And also implement loading the same way it is done for MokListRT -
> specifically via the EFI MOKvar config table & then via a variable.
>
> See 726bd8965a5f112d9601f7ce68effa1e46e02bf2 otherwise large MokListXRT
> will fail to parse.

Is this support available from shim now? Previously I thought only
MOK could be loaded from the config table, not MOKx.


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