[U-Boot] [PATCH 09/16] efi_loader: variable: add VendorKeys variable

AKASHI Takahiro
2019-11-13T00:52:59Z

The following variable is exported as UEFI specification defines:
VendorKeys: whether the system is configured to use only vendor-provided
keys or not
The value will have to be modified if a platform has its own way of
initializing signature database, in particular, PK.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
---
lib/efi_loader/efi_variable.c | 69 ++++++++++++++++++++++++++++++++---
1 file changed, 63 insertions(+), 6 deletions(-)

diff --git a/lib/efi_loader/efi_variable.c b/lib/efi_loader/efi_variable.c
index eb6135be6154..c7138183b0b0 100644
--- a/lib/efi_loader/efi_variable.c
+++ b/lib/efi_loader/efi_variable.c
@@ -25,6 +25,7 @@ enum efi_secure_mode {
const efi_guid_t efi_guid_cert_type_pkcs7 = EFI_CERT_TYPE_PKCS7_GUID;
static bool efi_secure_boot;
static int efi_secure_mode;
+static u8 efi_vendor_keys;

#define READ_ONLY BIT(31)

@@ -342,6 +343,8 @@ static efi_status_t efi_transfer_secure_state(enum efi_secure_mode mode)
return EFI_INVALID_PARAMETER;
}

+ efi_secure_mode = mode;
+
return EFI_SUCCESS;

err:
@@ -357,16 +360,46 @@ err:
*/
static efi_status_t efi_init_secure_state(void)
{
- efi_uintn_t size = 0;
+ enum efi_secure_mode mode;
+ efi_uintn_t size;
efi_status_t ret;

+ /*
+ * TODO:
+ * Since there is currently no "platform-specific" installation
+ * method of Platform Key, we can't say if VendorKeys is 0 or 1
+ * precisely.
+ */
+
+ size = 0;
ret = EFI_CALL(efi_get_variable(L"PK", &efi_global_variable_guid,
NULL, &size, NULL));
- if (ret == EFI_BUFFER_TOO_SMALL && IS_ENABLED(CONFIG_EFI_SECURE_BOOT))
- ret = efi_transfer_secure_state(EFI_MODE_USER);
- else
- ret = efi_transfer_secure_state(EFI_MODE_SETUP);
+ if (ret == EFI_BUFFER_TOO_SMALL) {
+ if (IS_ENABLED(CONFIG_EFI_SECURE_BOOT))
+ mode = EFI_MODE_USER;
+ else
+ mode = EFI_MODE_SETUP;
+
+ efi_vendor_keys = 0;
+ } else if (ret == EFI_NOT_FOUND) {
+ mode = EFI_MODE_SETUP;
+ efi_vendor_keys = 1;
+ } else {
+ goto err;
+ }

+ ret = efi_transfer_secure_state(mode);
+ if (ret == EFI_SUCCESS)
+ ret = efi_set_variable_internal(L"VendorKeys",
+ &efi_global_variable_guid,
+ EFI_VARIABLE_BOOTSERVICE_ACCESS
+ | EFI_VARIABLE_RUNTIME_ACCESS
+ | READ_ONLY,
+ sizeof(efi_vendor_keys),
+ &efi_vendor_keys,
+ false);
+
+err:
return ret;
}

@@ -1121,6 +1154,8 @@ out:
if (env_set(native_name, val)) {
ret = EFI_DEVICE_ERROR;
} else {
+ bool vendor_keys_modified = false;
+
if ((u16_strcmp(variable_name, L"PK") == 0 &&
guidcmp(vendor, &efi_global_variable_guid) == 0)) {
ret = efi_transfer_secure_state(
@@ -1128,8 +1163,30 @@ out:
EFI_MODE_USER));
if (ret != EFI_SUCCESS)
goto err;
+
+ if (efi_secure_mode != EFI_MODE_SETUP)
+ vendor_keys_modified = true;
+ } else if ((u16_strcmp(variable_name, L"KEK") == 0 &&
+ guidcmp(vendor, &efi_global_variable_guid) == 0)) {
+ if (efi_secure_mode != EFI_MODE_SETUP)
+ vendor_keys_modified = true;
+ }
+
+ /* update VendorKeys */
+ if (vendor_keys_modified & efi_vendor_keys) {
+ efi_vendor_keys = 0;
+ ret = efi_set_variable_internal(
+ L"VendorKeys",
+ &efi_global_variable_guid,
+ EFI_VARIABLE_BOOTSERVICE_ACCESS
+ | EFI_VARIABLE_RUNTIME_ACCESS
+ | READ_ONLY,
+ sizeof(efi_vendor_keys),
+ &efi_vendor_keys,
+ false);
+ } else {
+ ret = EFI_SUCCESS;
}
- ret = EFI_SUCCESS;
}

err:
--
2.21.0