Vboot Reference: Kernel Boot signing utility.

src/platform/vboot_reference/utils/kernel_utility.cc

Index: src/platform/vboot_reference/utils/kernel_utility.cc
diff --git a/src/platform/vboot_reference/utils/kernel_utility.cc b/src/platform/vboot_reference/utils/kernel_utility.cc
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+// 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 for manipulating verified boot firmware images.
+//
+
+#include "kernel_utility.h"
+
+#include <errno.h>
+#include <getopt.h>
+#include <stdint.h>  // Needed for UINT16_MAX.
+#include <stdlib.h>
+#include <unistd.h>
+
+#include <iostream>
+
+extern "C" {
+#include "file_keys.h"
+#include "kernel_image.h"
+#include "padding.h"
+#include "rsa_utility.h"
+#include "sha_utility.h"
+#include "utility.h"
+}
+
+extern int errno;
+using std::cerr;
+
+namespace vboot_reference {
+
+KernelUtility::KernelUtility(): image_(NULL),
+                                firmware_key_pub_(NULL),
+                                header_version_(1),
+                                firmware_sign_algorithm_(-1),
+                                kernel_sign_algorithm_(-1),
+                                kernel_key_version_(-1),
+                                kernel_version_(-1),
+                                is_generate_(false),
+                                is_verify_(false) {
+  // Populate kernel config options with defaults.
+  options_.version[0] = 1;
+  options_.version[1] = 0;
+  options_.kernel_len = 0;
+  options_.kernel_load_addr = 0;
+  options_.kernel_entry_addr = 0;
+}
+
+KernelUtility::~KernelUtility() {
+  RSAPublicKeyFree(firmware_key_pub_);
+  KernelImageFree(image_);
+}
+
+void KernelUtility::PrintUsage(void) {
+  cerr <<
+      "Utility to generate/verify a verified boot kernel image\n\n"
+      "Usage: firmware_utility <--generate|--verify> [OPTIONS]\n\n"
+      "For \"--verify\",  required OPTIONS are:\n"
+      "--in <infile>\t\t\tVerified boot kernel image to verify.\n"
+      "--firmware_key_pub <pubkeyfile>\tPre-processed public firmware key "
+      "to use for verification.\n\n"
+      "For \"--generate\", required OPTIONS are:\n"
+      "--firmware_key <privkeyfile>\tPrivate firmware signing key file\n"
+      "--kernel_key <privkeyfile>\tPrivate kernel signing key file\n"
+      "--kernel_key_pub <pubkeyfile>\tPre-processed public kernel signing"
+      " key\n"
+      "--firmware_sign_algorithm <algoid>\tSigning algorithm used by "
+      "the firmware\n"
+      "--kernel_sign_algorithm <algoid>\tSigning algorithm to use for kernel\n"
+      "--kernel_key_version <version#>\tKernel signing Key Version#\n"
+      "--kernel_version <version#>\tKernel Version#\n"
+      "--in <infile>\t\tKernel Image to sign\n"
+      "--out <outfile>\t\tOutput file for verified boot Kernel image\n\n"
+      "Optional arguments for \"--generate\" include:\n"
+      "--config_version <version>\n"
+      "--kernel_load_addr <addr>\n"
+      "--kernel_entry_addr <addr>\n\n"
+      "<algoid> (for --*_sign_algorithm) is one of the following:\n";
+  for (int i = 0; i < kNumAlgorithms; i++) {
+    cerr << i << " for " << algo_strings[i] << "\n";
+  }
+  cerr << "\n\n";
+}
+
+bool KernelUtility::ParseCmdLineOptions(int argc, char* argv[]) {
+  int option_index;
+  static struct option long_options[] = {
+    {"firmware_key", 1, 0, 0},
+    {"firmware_key_pub", 1, 0, 0},
+    {"kernel_key", 1, 0, 0},
+    {"kernel_key_pub", 1, 0, 0},
+    {"firmware_sign_algorithm", 1, 0, 0},
+    {"kernel_sign_algorithm", 1, 0, 0},
+    {"kernel_key_version", 1, 0, 0},
+    {"kernel_version", 1, 0, 0},
+    {"in", 1, 0, 0},
+    {"out", 1, 0, 0},
+    {"generate", 0, 0, 0},
+    {"verify", 0, 0, 0},
+    {"config_version", 1, 0, 0},
+    {"kernel_load_addr", 1, 0, 0},
+    {"kernel_entry_addr", 1, 0, 0},
+    {NULL, 0, 0, 0}
+  };
+  while (1) {
+    int i = getopt_long(argc, argv, "", long_options, &option_index);
+    if (-1 == i)  // Done with option processing.
+      break;
+    if ('?' == i)  // Invalid option found.
+      return false;
+
+    if (0 == i) {
+      switch (option_index) {
+        case 0:  // firmware_key
+          firmware_key_file_ = optarg;
+          break;
+        case 1:  // firmware_key_pub
+          firmware_key_pub_file_ = optarg;
+          break;
+        case 2:  // kernel_key
+          kernel_key_file_ = optarg;
+          break;
+        case 3:  // kernel_key_pub
+          kernel_key_pub_file_ = optarg;
+          break;
+        case 4:  // firmware_sign_algorithm
+          errno = 0;  // strtol() returns an error via errno
+          firmware_sign_algorithm_ = strtol(optarg,
+                                            reinterpret_cast<char**>(NULL), 10);
+          if (errno)
+            return false;
+          break;
+        case 5:  // kernel_sign_algorithm
+          errno = 0;
+          kernel_sign_algorithm_ = strtol(optarg,
+                                          reinterpret_cast<char**>(NULL), 10);
+          if (errno)
+            return false;
+          break;
+        case 6:  // kernel_key_version
+          errno = 0;
+          kernel_key_version_ = strtol(optarg,
+                                       reinterpret_cast<char**>(NULL), 10);
+          if (errno)
+            return false;
+          break;
+        case 7:  // kernel_version
+          errno = 0;
+          kernel_version_ = strtol(optarg,
+                                   reinterpret_cast<char**>(NULL), 10);
+          if (errno)
+            return false;
+          break;
+        case 8:  // in
+          in_file_ = optarg;
+          break;
+        case 9:  // out
+          out_file_ = optarg;
+          break;
+        case 10:  // generate
+          is_generate_ = true;
+          break;
+        case 11:  // verify
+          is_verify_ = true;
+          break;
+        case 12:  // config_version
+          if (2 != sscanf(optarg, "%d.%d", &options_.version[0],
+                          &options_.version[1]))
+            return false;
+          break;
+        case 13:  // kernel_load_addr
+          errno = 0;
+          options_.kernel_load_addr =
+              strtol(optarg, reinterpret_cast<char**>(NULL), 10);
+          if (errno)
+            return false;
+          break;
+        case 14:  // kernel_entry_addr
+          errno = 0;
+          options_.kernel_entry_addr =
+              strtol(optarg, reinterpret_cast<char**>(NULL), 10);
+
+          if (errno)
+            return false;
+          break;
+      }
+    }
+  }
+  return CheckOptions();
+}
+
+void KernelUtility::OutputSignedImage(void) {
+  if (image_) {
+    if (!WriteKernelImage(out_file_.c_str(), image_)) {
+      cerr << "Couldn't write verified boot kernel image to file "
+           << out_file_ <<".\n";
+    }
+  }
+}
+
+bool KernelUtility::GenerateSignedImage(void) {
+  uint32_t kernel_key_pub_len;
+  uint8_t* header_checksum;
+  DigestContext ctx;
+  image_ = KernelImageNew();
+
+  Memcpy(image_->magic, KERNEL_MAGIC, KERNEL_MAGIC_SIZE);
+
+  // TODO(gauravsh): make this a command line option.
+  image_->header_version = 1;
+  image_->firmware_sign_algorithm = (uint16_t) firmware_sign_algorithm_;
+  // Copy pre-processed public signing key.
+  image_->kernel_sign_algorithm = (uint16_t) kernel_sign_algorithm_;
+  image_->kernel_sign_key = BufferFromFile(kernel_key_pub_file_.c_str(),
+                                           &kernel_key_pub_len);
+  if (!image_->kernel_sign_key)
+    return false;
+  image_->kernel_key_version = kernel_key_version_;
+
+  // Update header length.
+  image_->header_len = GetKernelHeaderLen(image_);
+
+  // Calculate header checksum.
+  DigestInit(&ctx, SHA512_DIGEST_ALGORITHM);
+  DigestUpdate(&ctx, reinterpret_cast<uint8_t*>(&image_->header_version),
+               sizeof(image_->header_version));
+  DigestUpdate(&ctx, reinterpret_cast<uint8_t*>(&image_->header_len),
+               sizeof(image_->header_len));
+  DigestUpdate(&ctx, reinterpret_cast<uint8_t*>(&image_->kernel_sign_algorithm),
+               sizeof(image_->kernel_sign_algorithm));
+  DigestUpdate(&ctx, reinterpret_cast<uint8_t*>(&image_->kernel_key_version),
+               sizeof(image_->kernel_key_version));
+  DigestUpdate(&ctx, image_->kernel_sign_key,
+               RSAProcessedKeySize(image_->kernel_sign_algorithm));
+  header_checksum = DigestFinal(&ctx);
+  Memcpy(image_->header_checksum, header_checksum, SHA512_DIGEST_SIZE);
+  Free(header_checksum);
+
+  image_->kernel_version = kernel_version_;
+  image_->options.version[0] = options_.version[0];
+  image_->options.version[1] = options_.version[1];
+  image_->options.kernel_load_addr = options_.kernel_load_addr;
+  image_->options.kernel_entry_addr = options_.kernel_entry_addr;
+  image_->kernel_data = BufferFromFile(in_file_.c_str(),
+                                       &image_->options.kernel_len);
+  if (!image_)
+    return false;
+  // Generate and add the signatures.
+  if (!AddKernelKeySignature(image_, firmware_key_file_.c_str())) {
+    cerr << "Couldn't write key signature to verified boot image.\n";
+    return false;
+  }
+
+  if (!AddKernelSignature(image_, kernel_key_file_.c_str())) {
+    cerr << "Couldn't write firmware signature to verified boot image.\n";
+    return false;
+  }
+  return true;
+}
+
+bool KernelUtility::VerifySignedImage(void) {
+  int error;
+  firmware_key_pub_ = RSAPublicKeyFromFile(firmware_key_pub_file_.c_str());
+  image_ = ReadKernelImage(in_file_.c_str());
+
+  if (!firmware_key_pub_) {
+    cerr << "Couldn't read pre-processed public root key.\n";
+    return false;
+  }
+
+  if (!image_) {
+    cerr << "Couldn't read firmware image or malformed image.\n";
+    return false;
+  }
+  if (!(error = VerifyKernelImage(firmware_key_pub_, image_, 0)))
+    return true;
+  cerr << VerifyKernelErrorString(error) << "\n";
+  return false;
+}
+
+bool KernelUtility::CheckOptions(void) {
+  if (is_generate_ == is_verify_) {
+    cerr << "One of --generate or --verify must be specified.\n";
+    return false;
+  }
+  // Common required options.
+  if (in_file_.empty()) {
+    cerr << "No input file specified.\n";
+    return false;
+  }
+  // Required options for --verify.
+  if (is_verify_ && firmware_key_pub_file_.empty()) {
+    cerr << "No pre-processed public firmware key file specified.\n";
+    return false;
+  }
+  // Required options for --generate.
+  if (is_generate_) {
+    if (firmware_key_file_.empty()) {
+      cerr << "No firmware key file specified.\n";
+      return false;
+    }
+    if (kernel_key_file_.empty()) {
+      cerr << "No kernel key file specified.\n";
+      return false;
+    }
+    if (kernel_key_pub_file_.empty()) {
+      cerr << "No pre-processed public kernel key file specified\n";
+      return false;
+    }
+    if (kernel_key_version_ <= 0 || kernel_key_version_ > UINT16_MAX) {
+      cerr << "Invalid or no kernel key version specified.\n";
+      return false;
+    }
+    if (firmware_sign_algorithm_ < 0 ||
+        firmware_sign_algorithm_ >= kNumAlgorithms) {
+      cerr << "Invalid or no firmware signing key algorithm specified.\n";
+      return false;
+    }
+    if (kernel_sign_algorithm_ < 0 ||
+        kernel_sign_algorithm_ >= kNumAlgorithms) {
+      cerr << "Invalid or no kernel signing key algorithm specified.\n";
+      return false;
+    }
+    if (kernel_version_ <=0 || kernel_version_ > UINT16_MAX) {
+      cerr << "Invalid or no kernel version specified.\n";
+      return false;
+    }
+    if (out_file_.empty()) {
+      cerr <<"No output file specified.\n";
+      return false;
+    }
+  }
+  return true;
+}
+
+}  // namespace vboot_reference
+
+int main(int argc, char* argv[]) {
+  vboot_reference::KernelUtility fu;
+  if (!fu.ParseCmdLineOptions(argc, argv)) {
+    fu.PrintUsage();
+    return -1;
+  }
+  if (fu.is_generate()) {
+    if (!fu.GenerateSignedImage())
+      return -1;
+    fu.OutputSignedImage();
+  }
+  if (fu.is_verify()) {
+    cerr << "Verification ";
+    if (fu.VerifySignedImage())
+      cerr << "SUCCESS.\n";
+    else
+      cerr << "FAILURE.\n";
+  }
+  return 0;
+}