path: root/security/integrity
diff options
authorLenny Szubowicz <>2020-09-04 21:31:07 -0400
committerArd Biesheuvel <>2020-09-16 18:53:42 +0300
commit726bd8965a5f112d9601f7ce68effa1e46e02bf2 (patch)
treec476fcad781d963d90a6248b083457ff465de9a5 /security/integrity
parent38a1f03aa24094b4a8de846700cb6cb21cc06468 (diff)
integrity: Load certs from the EFI MOK config table
Because of system-specific EFI firmware limitations, EFI volatile variables may not be capable of holding the required contents of the Machine Owner Key (MOK) certificate store when the certificate list grows above some size. Therefore, an EFI boot loader may pass the MOK certs via a EFI configuration table created specifically for this purpose to avoid this firmware limitation. An EFI configuration table is a much more primitive mechanism compared to EFI variables and is well suited for one-way passage of static information from a pre-OS environment to the kernel. This patch adds the support to load certs from the MokListRT entry in the MOK variable configuration table, if it's present. The pre-existing support to load certs from the MokListRT EFI variable remains and is used if the EFI MOK configuration table isn't present or can't be successfully used. Signed-off-by: Lenny Szubowicz <> Link: Signed-off-by: Ard Biesheuvel <>
Diffstat (limited to 'security/integrity')
1 files changed, 22 insertions, 0 deletions
diff --git a/security/integrity/platform_certs/load_uefi.c b/security/integrity/platform_certs/load_uefi.c
index c1c622b4dc78..ee4b4c666854 100644
--- a/security/integrity/platform_certs/load_uefi.c
+++ b/security/integrity/platform_certs/load_uefi.c
@@ -71,16 +71,38 @@ static __init void *get_cert_list(efi_char16_t *name, efi_guid_t *guid,
* Load the certs contained in the UEFI MokListRT database into the
* platform trusted keyring.
+ * This routine checks the EFI MOK config table first. If and only if
+ * that fails, this routine uses the MokListRT ordinary UEFI variable.
+ *
* Return: Status
static int __init load_moklist_certs(void)
+ struct efi_mokvar_table_entry *mokvar_entry;
efi_guid_t mok_var = EFI_SHIM_LOCK_GUID;
void *mok;
unsigned long moksize;
efi_status_t status;
int rc;
+ /* First try to load certs from the EFI MOKvar config table.
+ * It's not an error if the MOKvar config table doesn't exist
+ * or the MokListRT entry is not found in it.
+ */
+ mokvar_entry = efi_mokvar_entry_find("MokListRT");
+ if (mokvar_entry) {
+ rc = parse_efi_signature_list("UEFI:MokListRT (MOKvar table)",
+ mokvar_entry->data,
+ mokvar_entry->data_size,
+ get_handler_for_db);
+ /* All done if that worked. */
+ if (!rc)
+ return rc;
+ pr_err("Couldn't parse MokListRT signatures from EFI MOKvar config table: %d\n",
+ rc);
+ }
/* Get MokListRT. It might not exist, so it isn't an error
* if we can't get it.