Add --subkey_in and --subkey_out options to firmware signing utility.

src/platform/vboot_reference/vfirmware/firmware_image.c

 /* Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  *
  * Functions for generating and manipulating a verified boot firmware image.
  */
 
 #include "firmware_image.h"
 
 #include <sys/types.h>
@@ skipping 241 matching lines @@
 
   if (st.overrun || st.remaining_len != 0) { /* Underrun or Overrun. */
     Free(firmware_blob);
     return NULL;
   }
   return firmware_blob;
 }
 
 int WriteFirmwareImage(const char* output_file,
                        const FirmwareImage* image,
-                       int is_only_vblock) {
+                       int is_only_vblock,
+                       int is_subkey_out) {
   int fd;
   int success = 1;
   uint8_t* firmware_blob;
+  uint8_t* subkey_out_buf = NULL;
+  uint8_t* subkey_header = NULL;
   uint64_t blob_len;
 
   if (!image)
     return 0;
   if (-1 == (fd = creat(output_file, 0666))) {
     debug("Couldn't open file for writing.\n");
     return 0;
   }
+  if (is_subkey_out) {
+    blob_len = GetFirmwareHeaderLen(image) +
+        siglen_map[ROOT_SIGNATURE_ALGORITHM];
+    subkey_out_buf = (uint8_t*) Malloc(blob_len);
+    subkey_header = GetFirmwareHeaderBlob(image);
+    Memcpy(subkey_out_buf, subkey_header, GetFirmwareHeaderLen(image));
+    Memcpy(subkey_out_buf + GetFirmwareHeaderLen(image),
+           image->firmware_key_signature,
+           siglen_map[ROOT_SIGNATURE_ALGORITHM]);
+    if (blob_len != write(fd, subkey_out_buf, blob_len)) {
+      debug("Couldn't write kernel subkey header to file: %s\n",
+            output_file);
+      success = 0;
+    }
+    Free(subkey_header);
+    Free(subkey_out_buf);
+    close(fd);
+    return success;
+  }
 
   firmware_blob = GetFirmwareBlob(image, &blob_len);
   if (!firmware_blob) {
     debug("Couldn't create firmware blob from FirmwareImage.\n");
     return 0;
   }
   if (!is_only_vblock) {
     if (blob_len != write(fd, firmware_blob, blob_len)) {
       debug("Couldn't write Firmware Image to file: %s\n", output_file);
       success = 0;
@@ skipping 188 matching lines @@
     Free(firmware_buf);
     return 0;
   }
   image->firmware_signature = (uint8_t*) Malloc(signature_len);
   Memcpy(image->firmware_signature, firmware_signature, signature_len);
   Free(firmware_signature);
   Free(firmware_buf);
   Free(preamble_blob);
   return 1;
 }