Add --subkey_in option to kernel signing utility.

src/platform/vboot_reference/vkernel/kernel_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 kernel image.
  * (Userland portion)
  */
 #include "kernel_image.h"
 
 #include <fcntl.h>
@@ skipping 49 matching lines @@
     GetKernelPreambleLen(image->kernel_sign_algorithm) +
     kernel_signature_len;
 }
 
 
 KernelImage* ReadKernelImage(const char* input_file) {
   uint64_t file_size;
   uint64_t on_disk_header_size;
   uint64_t on_disk_padding;
   int header_len = 0;
-  int firmware_sign_key_len;
   int kernel_key_signature_len;
   int kernel_sign_key_len;
   int kernel_signature_len;
   uint8_t* kernel_buf;
   uint8_t header_checksum[FIELD_LEN(header_checksum)];
   MemcpyState st;
   KernelImage* image = KernelImageNew();
 
   if (!image)
     return NULL;
@@ skipping 25 matching lines @@
     return NULL;
   }
 
   /* Valid Kernel Signing Algorithm? */
   if (image->kernel_sign_algorithm >= kNumAlgorithms) {
     Free(kernel_buf);
     return NULL;
   }
 
   /* Compute size of pre-processed RSA public keys and signatures. */
-  firmware_sign_key_len = RSAProcessedKeySize(image->firmware_sign_algorithm);
   kernel_key_signature_len  = siglen_map[image->firmware_sign_algorithm];
   kernel_sign_key_len = RSAProcessedKeySize(image->kernel_sign_algorithm);
   kernel_signature_len = siglen_map[image->kernel_sign_algorithm];
 
   /* Check whether key header length is correct. */
   header_len = GetKernelHeaderLen(image);
   if (header_len != image->header_len) {
     debug("Header length mismatch. Got: %d, Expected: %d\n",
             image->header_len, header_len);
     Free(kernel_buf);
@@ skipping 624 matching lines @@
   // Clean up and return the blob.
 done3:
   Free(bootloader_buf);
 done2:
   Free(config_buf);
 done1:
   Free(kernel_buf);
 done0:
   return blob;
 }