Vboot Reference: Add the "real" reference firmware verification function (VerifyFirmware).

src/platform/vboot_reference/crypto/sha_utility.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.
  *
  * Utility functions for message digest functions.
  */
 
 #include "sha_utility.h"
 
 #include <fcntl.h>
@@ skipping 90 matching lines @@
   while ( (len = read(input_fd, data, SHA1_BLOCK_SIZE)) ==
           SHA1_BLOCK_SIZE)
     DigestUpdate(&ctx, data, len);
   if (len != -1)
     DigestUpdate(&ctx, data, len);
   digest = DigestFinal(&ctx);
   close(input_fd);
   return digest;
 }
 
-uint8_t* DigestBuf(uint8_t* buf, int len, int sig_algorithm) {
+uint8_t* DigestBuf(const uint8_t* buf, int len, int sig_algorithm) {
   uint8_t* digest = (uint8_t*) Malloc(SHA512_DIGEST_SIZE); /* Use the max. */
   /* Define an array mapping [sig_algorithm] to function pointers to the
    * SHA{1|256|512} functions.
    */
   typedef uint8_t* (*Hash_ptr) (const uint8_t*, int, uint8_t*);
   Hash_ptr hash[] = {
     SHA1,  /* RSA 1024 */
     SHA256,
     SHA512,
     SHA1,  /* RSA 2048 */
     SHA256,
     SHA512,
     SHA1,  /* RSA 4096 */
     SHA256,
     SHA512,
     SHA1,  /* RSA 8192 */
     SHA256,
     SHA512,
   };
   /* Call the appropriate hash function. */
   return hash[sig_algorithm](buf, len, digest);
 }