[PATCH v3 3/3] efi_loader: correct determination of secure boot state

[Heinrich Schuchardt]

From: Heinrich Schuchardt <xypron.glpk at gmx.de>

When U-Boot is started we have to use the existing variables to determine
in which secure boot state we are.

* If a platform key PK is present and DeployedMode=1, we are in deployed
  mode.
* If no platform key PK is present and AuditMode=1, we are in audit mode.
* Otherwise if a platform key is present, we are in user mode.
* Otherwise if no platform key is present, we are in setup mode.

Signed-off-by: Heinrich Schuchardt <xypron.glpk at gmx.de>
---
 lib/efi_loader/efi_var_common.c | 39 ++++++++++++++++++++++++++-------
 1 file changed, 31 insertions(+), 8 deletions(-)

diff --git a/lib/efi_loader/efi_var_common.c b/lib/efi_loader/efi_var_common.c
index c744e2fd91..a00bbf1620 100644
--- a/lib/efi_loader/efi_var_common.c
+++ b/lib/efi_loader/efi_var_common.c
@@ -314,17 +314,40 @@ err:
 
 efi_status_t efi_init_secure_state(void)
 {
-	enum efi_secure_mode mode = EFI_MODE_SETUP;
+	enum efi_secure_mode mode;
 	u8 efi_vendor_keys = 0;
-	efi_uintn_t size = 0;
+	efi_uintn_t size;
 	efi_status_t ret;
-
-	ret = efi_get_variable_int(L"PK", &efi_global_variable_guid,
-				   NULL, &size, NULL, NULL);
-	if (ret == EFI_BUFFER_TOO_SMALL) {
-		if (IS_ENABLED(CONFIG_EFI_SECURE_BOOT))
-			mode = EFI_MODE_USER;
+	u8 deployed_mode = 0;
+	u8 audit_mode = 0;
+	u8 setup_mode = 1;
+
+	if (IS_ENABLED(CONFIG_EFI_SECURE_BOOT)) {
+		size = sizeof(deployed_mode);
+		ret = efi_get_variable_int(u"DeployedMode", &efi_global_variable_guid,
+					   NULL, &size, &deployed_mode, NULL);
+		size = sizeof(audit_mode);
+		ret = efi_get_variable_int(u"AuditMode", &efi_global_variable_guid,
+					   NULL, &size, &audit_mode, NULL);
+		size = 0;
+		ret = efi_get_variable_int(u"PK", &efi_global_variable_guid,
+					   NULL, &size, NULL, NULL);
+		if (ret == EFI_BUFFER_TOO_SMALL) {
+			setup_mode = 0;
+			audit_mode = 0;
+		} else {
+			setup_mode = 1;
+			deployed_mode = 0;
+		}
 	}
+	if (deployed_mode)
+		mode = EFI_MODE_DEPLOYED;
+	else if (audit_mode)
+		mode = EFI_MODE_AUDIT;
+	else if (setup_mode)
+		mode = EFI_MODE_SETUP;
+	else
+		mode = EFI_MODE_USER;
 
 	ret = efi_transfer_secure_state(mode);
 	if (ret != EFI_SUCCESS)
-- 
2.32.0