efi_loader: Allow capsule update on-disk without checking OsIndications

Although U-Boot supports capsule update on-disk, it's lack of support for
SetVariable at runtime prevents applications like fwupd from using it.

In order to perform the capsule update on-disk the spec says that the OS
must copy the capsule to the \EFI\UpdateCapsule directory and set a bit in
the OsIndications variable.  The firmware then checks for the
EFI_OS_INDICATIONS_FILE_CAPSULE_DELIVERY_SUPPORTED bit in OsIndications
variable, which is set by the submitter to trigger processing of the
capsule on the next reboot.

Let's add a config option which ignores the bit and just relies on the
capsule being present. Since U-Boot deletes the capsule while processing
it, we won't end up applying it multiple times.

Note that this is allowed for all capsules. In the future, once
authenticated capsules are fully supported, we can limit the functionality
to those only.

Signed-off-by: apalos <[email protected]>

Reword Kconfig description.
Reviewed-by: Heinrich Schuchardt <[email protected]>

Signed-off-by: Heinrich Schuchardt <[email protected]>

lib/efi_loader/Kconfig

@@ -137,6 +137,16 @@ config EFI_CAPSULE_ON_DISK
 	  under a specific directory on UEFI system partition instead of
 	  via UpdateCapsule API.
 
+config EFI_IGNORE_OSINDICATIONS
+	bool "Ignore OsIndications for CapsuleUpdate on-disk"
+	depends on EFI_CAPSULE_ON_DISK
+	default n
+	help
+	  There are boards where U-Boot does not support SetVariable at runtime.
+	  Select this option if you want to use the capsule-on-disk feature
+	  without setting the EFI_OS_INDICATIONS_FILE_CAPSULE_DELIVERY_SUPPORTED
+	  flag in variable OsIndications.
+
 config EFI_CAPSULE_ON_DISK_EARLY
 	bool "Initiate capsule-on-disk at U-Boot boottime"
 	depends on EFI_CAPSULE_ON_DISK

lib/efi_loader/efi_capsule.c

@@ -948,6 +948,33 @@ efi_status_t __weak efi_load_capsule_drivers(void)
 	return ret;
 }
 
+/**
+ * check_run_capsules - Check whether capsule update should run
+ *
+ * The spec says OsIndications must be set in order to run the capsule update
+ * on-disk.  Since U-Boot doesn't support runtime SetVariable, allow capsules to
+ * run explicitly if CONFIG_EFI_IGNORE_OSINDICATIONS is selected
+ */
+static bool check_run_capsules(void)
+{
+	u64 os_indications;
+	efi_uintn_t size;
+	efi_status_t ret;
+
+	if (IS_ENABLED(CONFIG_EFI_IGNORE_OSINDICATIONS))
+		return true;
+
+	size = sizeof(os_indications);
+	ret = efi_get_variable_int(L"OsIndications", &efi_global_variable_guid,
+				   NULL, &size, &os_indications, NULL);
+	if (ret == EFI_SUCCESS &&
+	    (os_indications
+	      & EFI_OS_INDICATIONS_FILE_CAPSULE_DELIVERY_SUPPORTED))
+		return true;
+
+	return false;
+}
+
 /**
  * efi_launch_capsule - launch capsules
  *
@@ -958,20 +985,13 @@ efi_status_t __weak efi_load_capsule_drivers(void)
  */
 efi_status_t efi_launch_capsules(void)
 {
-	u64 os_indications;
-	efi_uintn_t size;
 	struct efi_capsule_header *capsule = NULL;
 	u16 **files;
 	unsigned int nfiles, index, i;
 	u16 variable_name16[12];
 	efi_status_t ret;
 
-	size = sizeof(os_indications);
-	ret = efi_get_variable_int(L"OsIndications", &efi_global_variable_guid,
-				   NULL, &size, &os_indications, NULL);
-	if (ret != EFI_SUCCESS ||
-	    !(os_indications
-	      & EFI_OS_INDICATIONS_FILE_CAPSULE_DELIVERY_SUPPORTED))
+	if (!check_run_capsules())
 		return EFI_SUCCESS;
 
 	index = get_last_capsule();