diff options
| -rw-r--r-- | drivers/firmware/efi/libstub/secureboot.c | 25 |
1 files changed, 24 insertions, 1 deletions
diff --git a/drivers/firmware/efi/libstub/secureboot.c b/drivers/firmware/efi/libstub/secureboot.c index b20b8b460d77..6def402bf569 100644 --- a/drivers/firmware/efi/libstub/secureboot.c +++ b/drivers/firmware/efi/libstub/secureboot.c @@ -21,6 +21,12 @@ static const efi_char16_t const efi_SetupMode_name[] = { 'S', 'e', 't', 'u', 'p', 'M', 'o', 'd', 'e', 0 }; +/* SHIM variables */ +static const efi_guid_t shim_guid = EFI_SHIM_LOCK_GUID; +static efi_char16_t const shim_MokSBState_name[] = { + 'M', 'o', 'k', 'S', 'B', 'S', 't', 'a', 't', 'e', 0 +}; + #define get_efi_var(name, vendor, ...) \ efi_call_runtime(get_variable, \ (efi_char16_t *)(name), (efi_guid_t *)(vendor), \ @@ -31,7 +37,8 @@ static const efi_char16_t const efi_SetupMode_name[] = { */ enum efi_secureboot_mode efi_get_secureboot(efi_system_table_t *sys_table_arg) { - u8 secboot, setupmode; + u32 attr; + u8 secboot, setupmode, moksbstate; unsigned long size; efi_status_t status; @@ -50,6 +57,22 @@ enum efi_secureboot_mode efi_get_secureboot(efi_system_table_t *sys_table_arg) if (secboot == 0 || setupmode == 1) return efi_secureboot_mode_disabled; + /* + * See if a user has put the shim into insecure mode. If so, and if the + * variable doesn't have the runtime attribute set, we might as well + * honor that. + */ + size = sizeof(moksbstate); + status = get_efi_var(shim_MokSBState_name, &shim_guid, + &attr, &size, &moksbstate); + + /* If it fails, we don't care why. Default to secure */ + if (status != EFI_SUCCESS) + goto secure_boot_enabled; + if (!(attr & EFI_VARIABLE_RUNTIME_ACCESS) && moksbstate == 1) + return efi_secureboot_mode_disabled; + +secure_boot_enabled: pr_efi(sys_table_arg, "UEFI Secure Boot is enabled.\n"); return efi_secureboot_mode_enabled; |