[PATCH v4 12/14] efi_loader: Enable uefi capsule authentication

[Sughosh Ganu]

Add support for enabling uefi capsule authentication. This feature is
enabled by setting the environment variable
"capsule_authentication_enabled".

The following configs are needed for enabling uefi capsule update and
capsule authentication features on the platform.

CONFIG_EFI_HAVE_CAPSULE_SUPPORT=y
CONFIG_EFI_CAPSULE_ON_DISK=y
CONFIG_EFI_CAPSULE_FIRMWARE_MANAGEMENT=y
CONFIG_EFI_CAPSULE_FIRMWARE=y
CONFIG_EFI_CAPSULE_FIRMWARE_RAW=y
CONFIG_EFI_CAPSULE_AUTHENTICATE=y

Signed-off-by: Sughosh Ganu <sughosh.ganu at linaro.org>
---

Changes since V3: None

 lib/efi_loader/efi_firmware.c | 36 ++++++++++++++++++++++++++++++++++-
 1 file changed, 35 insertions(+), 1 deletion(-)

diff --git a/lib/efi_loader/efi_firmware.c b/lib/efi_loader/efi_firmware.c
index 5d2ecde2f1..5e401bbca2 100644
--- a/lib/efi_loader/efi_firmware.c
+++ b/lib/efi_loader/efi_firmware.c
@@ -184,9 +184,16 @@ static efi_status_t efi_get_dfu_info(
 		image_info[i].version_name = NULL; /* not supported */
 		image_info[i].size = 0;
 		image_info[i].attributes_supported =
-				IMAGE_ATTRIBUTE_IMAGE_UPDATABLE;
+			IMAGE_ATTRIBUTE_IMAGE_UPDATABLE |
+			IMAGE_ATTRIBUTE_AUTHENTICATION_REQUIRED;
 		image_info[i].attributes_setting =
 				IMAGE_ATTRIBUTE_IMAGE_UPDATABLE;
+
+		/* Check if the capsule authentication is enabled */
+		if (env_get("capsule_authentication_enabled"))
+			image_info[0].attributes_setting |=
+				IMAGE_ATTRIBUTE_AUTHENTICATION_REQUIRED;
+
 		image_info[i].lowest_supported_image_version = 0;
 		image_info[i].last_attempt_version = 0;
 		image_info[i].last_attempt_status = LAST_ATTEMPT_STATUS_SUCCESS;
@@ -403,6 +410,9 @@ efi_status_t EFIAPI efi_firmware_raw_set_image(
 {
 	u32 fmp_hdr_signature;
 	struct fmp_payload_header *header;
+	void *capsule_payload;
+	efi_status_t status;
+	efi_uintn_t capsule_payload_size;
 
 	EFI_ENTRY("%p %d %p %ld %p %p %p\n", this, image_index, image,
 		  image_size, vendor_code, progress, abort_reason);
@@ -410,6 +420,30 @@ efi_status_t EFIAPI efi_firmware_raw_set_image(
 	if (!image)
 		return EFI_EXIT(EFI_INVALID_PARAMETER);
 
+	/* Authenticate the capsule if authentication enabled */
+	if (IS_ENABLED(CONFIG_EFI_CAPSULE_AUTHENTICATE) &&
+	    env_get("capsule_authentication_enabled")) {
+		capsule_payload = NULL;
+		capsule_payload_size = 0;
+		status = efi_capsule_authenticate(image, image_size,
+						  &capsule_payload,
+						  &capsule_payload_size);
+
+		if (status == EFI_SECURITY_VIOLATION) {
+			printf("Capsule authentication check failed. Aborting update\n");
+			return EFI_EXIT(status);
+		} else if (status != EFI_SUCCESS) {
+			return EFI_EXIT(status);
+		}
+
+		debug("Capsule authentication successfull\n");
+		image = capsule_payload;
+		image_size = capsule_payload_size;
+	} else {
+		debug("Capsule authentication disabled. ");
+		debug("Updating capsule without authenticating.\n");
+	}
+
 	fmp_hdr_signature = FMP_PAYLOAD_HDR_SIGNATURE;
 	header = (void *)image;
 
-- 
2.17.1