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SubjectRe: [PATCH 4/4] integrity: Load mokx variables into the blacklist keyring
Date
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.

> /* Load the MokListRT certs */
> rc = load_moklist_certs();
>
>
>
>

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