/* 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.
 */

/* Routines for verifying a file's signature. Useful in testing the core
 * RSA verification implementation.
 */

#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>

#include "sha_utility.h"
#include "padding.h"
#include "rsa.h"
#include "rsa_utility.h"
#include "verify_data.h"

RSAPublicKey* read_RSAkey(char* input_file) {
  int key_fd;
  int buf_len;
  struct stat stat_fd;
  uint8_t* buf = NULL;

  if ((key_fd = open(input_file, O_RDONLY)) == -1) {
    fprintf(stderr, "Couldn't open pre-processed key file\n");
    return NULL;
  }

  if (-1 == fstat(key_fd, &stat_fd)) {
    fprintf(stderr, "Couldn't stat key file\n");
    return NULL;
  }
  buf_len = stat_fd.st_size;

  /* Read entire key binary blob into a buffer. */
  buf = (uint8_t*) malloc(buf_len);
  if (!buf)
    return NULL;

  if (buf_len != read(key_fd, buf, buf_len)) {
    fprintf(stderr, "Couldn't read key into a buffer.\n");
    return NULL;
  }

  close(key_fd);
  return RSAPublicKeyFromBuf(buf, buf_len);
}

uint8_t* read_signature(char* input_file, int len) {
  int i, sigfd;
  uint8_t* signature = NULL;
  if ((sigfd = open(input_file, O_RDONLY)) == -1) {
    fprintf(stderr, "Couldn't open signature file\n");
    return NULL;
  }

  /* Read the signature into a buffer*/
  signature = (uint8_t*) malloc(len);
  if (!signature)
    return NULL;

  if( (i = read(sigfd, signature, len)) != len ) {
    fprintf(stderr, "Wrong signature length - Expected = %d, Received = %d\n",
            len, i);
    close(sigfd);
    return NULL;
  }

  close(sigfd);
  return signature;
}


int main(int argc, char* argv[]) {
  int i, algorithm, sig_len;
  int return_code = 1;  /* Default to error. */
  uint8_t* digest = NULL;
  uint8_t* signature = NULL;
  RSAPublicKey* key = NULL;

  if (argc!=5) {
    fprintf(stderr, "Usage: %s <algorithm> <key file> <signature file>"
            " <input file>\n\n", argv[0]);
    fprintf(stderr, "where <algorithm> depends on the signature algorithm"
            " used:\n");
    for(i = 0; i<kNumAlgorithms; i++)
      fprintf(stderr, "\t%d for %s\n", i, algo_strings[i]);
    return -1;
  }

  algorithm = atoi(argv[1]);
  if (algorithm >= kNumAlgorithms) {
    fprintf(stderr, "Invalid Algorithm!\n");
    return 0;
  }
  /* Length of the RSA Signature/RSA Key */
  sig_len = siglen_map[algorithm] * sizeof(uint32_t);

  if (!(key = read_RSAkey(argv[2])))
    goto failure;
  if (!(signature = read_signature(argv[3], sig_len)))
    goto failure;
  if (!(digest = DigestFile(argv[4], algorithm)))
    goto failure;
  if(RSA_verify(key, signature, sig_len, algorithm, digest)) {
    return_code = 0;
    fprintf(stderr, "Signature Verification SUCCEEDED.\n");
  }
  else {
    fprintf(stderr, "Signature Verification FAILED!\n");
  }

failure:
  free(key);
  free(signature);
  free(digest);

  return return_code;
}