efi_loader: capsule: remove authentication data

If capsule authentication is disabled and yet a capsule file is signed,
its signature must be removed from image data to flush.
Otherwise, the firmware will be corrupted after update.

Fixes: 04be98bd6bcf ("efi: capsule: Add support for uefi capsule
	authentication")
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>

diff --git a/lib/efi_loader/efi_capsule.c b/lib/efi_loader/efi_capsule.c
index 3c029378de0a53585204014ab93ada654613f430..26990bc2df4a21b1e4420731e212156f4494b012 100644 (file)
--- a/lib/efi_loader/efi_capsule.c
+++ b/lib/efi_loader/efi_capsule.c
@@ -218,6 +218,39 @@ skip:
        return NULL;
 }
 
+/**
+ * efi_remove_auth_hdr - remove authentication data from image
+ * @image:     Pointer to pointer to Image
+ * @image_size:        Pointer to Image size
+ *
+ * Remove the authentication data from image if possible.
+ * Update @image and @image_size.
+ *
+ * Return:             status code
+ */
+static efi_status_t efi_remove_auth_hdr(void **image, efi_uintn_t *image_size)
+{
+       struct efi_firmware_image_authentication *auth_hdr;
+       efi_status_t ret = EFI_INVALID_PARAMETER;
+
+       auth_hdr = (struct efi_firmware_image_authentication *)*image;
+       if (*image_size < sizeof(*auth_hdr))
+               goto out;
+
+       if (auth_hdr->auth_info.hdr.dwLength <=
+           offsetof(struct win_certificate_uefi_guid, cert_data))
+               goto out;
+
+       *image = (uint8_t *)*image + sizeof(auth_hdr->monotonic_count) +
+               auth_hdr->auth_info.hdr.dwLength;
+       *image_size = *image_size - auth_hdr->auth_info.hdr.dwLength -
+               sizeof(auth_hdr->monotonic_count);
+
+       ret = EFI_SUCCESS;
+out:
+       return ret;
+}
+
 #if defined(CONFIG_EFI_CAPSULE_AUTHENTICATE)
 
 static int efi_get_public_key_data(void **pkey, efi_uintn_t *pkey_len)
@@ -254,21 +287,15 @@ efi_status_t efi_capsule_authenticate(const void *capsule, efi_uintn_t capsule_s
        if (capsule == NULL || capsule_size == 0)
                goto out;
 
-       auth_hdr = (struct efi_firmware_image_authentication *)capsule;
-       if (capsule_size < sizeof(*auth_hdr))
-               goto out;
-
-       if (auth_hdr->auth_info.hdr.dwLength <=
-           offsetof(struct win_certificate_uefi_guid, cert_data))
+       *image = (uint8_t *)capsule;
+       *image_size = capsule_size;
+       if (efi_remove_auth_hdr(image, image_size) != EFI_SUCCESS)
                goto out;
 
+       auth_hdr = (struct efi_firmware_image_authentication *)capsule;
        if (guidcmp(&auth_hdr->auth_info.cert_type, &efi_guid_cert_type_pkcs7))
                goto out;
 
-       *image = (uint8_t *)capsule + sizeof(auth_hdr->monotonic_count) +
-               auth_hdr->auth_info.hdr.dwLength;
-       *image_size = capsule_size - auth_hdr->auth_info.hdr.dwLength -
-               sizeof(auth_hdr->monotonic_count);
        memcpy(&monotonic_count, &auth_hdr->monotonic_count,
               sizeof(monotonic_count));
 
@@ -348,7 +375,7 @@ static efi_status_t efi_capsule_update_firmware(
 {
        struct efi_firmware_management_capsule_header *capsule;
        struct efi_firmware_management_capsule_image_header *image;
-       size_t capsule_size;
+       size_t capsule_size, image_binary_size;
        void *image_binary, *vendor_code;
        efi_handle_t *handles;
        efi_uintn_t no_handles;
@@ -410,13 +437,30 @@ static efi_status_t efi_capsule_update_firmware(
                }
 
                /* do update */
+               if (IS_ENABLED(CONFIG_EFI_CAPSULE_AUTHENTICATE) &&
+                   !(image->image_capsule_support &
+                               CAPSULE_SUPPORT_AUTHENTICATION)) {
+                       /* no signature */
+                       ret = EFI_SECURITY_VIOLATION;
+                       goto out;
+               }
+
                image_binary = (void *)image + sizeof(*image);
-               vendor_code = image_binary + image->update_image_size;
+               image_binary_size = image->update_image_size;
+               vendor_code = image_binary + image_binary_size;
+               if (!IS_ENABLED(CONFIG_EFI_CAPSULE_AUTHENTICATE) &&
+                   (image->image_capsule_support &
+                               CAPSULE_SUPPORT_AUTHENTICATION)) {
+                       ret = efi_remove_auth_hdr(&image_binary,
+                                                 &image_binary_size);
+                       if (ret != EFI_SUCCESS)
+                               goto out;
+               }
 
                abort_reason = NULL;
                ret = EFI_CALL(fmp->set_image(fmp, image->update_image_index,
                                              image_binary,
-                                             image->update_image_size,
+                                             image_binary_size,
                                              vendor_code, NULL,
                                              &abort_reason));
                if (ret != EFI_SUCCESS) {