test/fake_avb_ops.cc

/*
 * Copyright (C) 2016 The Android Open Source Project
 *
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use, copy,
 * modify, merge, publish, distribute, sublicense, and/or sell copies
 * of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include <iostream>

#include <endian.h>
#include <errno.h>
#include <inttypes.h>
#include <string.h>

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

#include <base/files/file_util.h>
#include <base/strings/string_util.h>
#include <base/strings/stringprintf.h>

#include "fake_avb_ops.h"

AvbIOResult FakeAvbOps::read_from_partition(const char* partition,
                                            int64_t offset, size_t num_bytes,
                                            void* buffer,
                                            size_t* out_num_read) {
  base::FilePath path =
      partition_dir_.Append(std::string(partition)).AddExtension("img");

  if (offset < 0) {
    int64_t file_size;
    if (!base::GetFileSize(path, &file_size)) {
      fprintf(stderr, "Error getting size of file '%s'\n",
              path.value().c_str());
      return AVB_IO_RESULT_ERROR_IO;
    }
    offset = file_size - (-offset);
  }

  int fd = open(path.value().c_str(), O_RDONLY);
  if (fd < 0) {
    fprintf(stderr, "Error opening file '%s': %s\n", path.value().c_str(),
            strerror(errno));
    return AVB_IO_RESULT_ERROR_IO;
  }
  if (lseek(fd, offset, SEEK_SET) != offset) {
    fprintf(stderr, "Error seeking to pos %zd in file %s: %s\n", offset,
            path.value().c_str(), strerror(errno));
    close(fd);
    return AVB_IO_RESULT_ERROR_IO;
  }
  ssize_t num_read = read(fd, buffer, num_bytes);
  if (num_read < 0) {
    fprintf(stderr,
            "Error reading %zd bytes from pos %" PRId64 " in file %s: %s\n",
            num_bytes, offset, path.value().c_str(), strerror(errno));
    close(fd);
    return AVB_IO_RESULT_ERROR_IO;
  }
  close(fd);

  if (out_num_read != NULL) {
    *out_num_read = num_read;
  }

  return AVB_IO_RESULT_OK;
}

AvbIOResult FakeAvbOps::write_to_partition(const char* partition,
                                           int64_t offset, size_t num_bytes,
                                           const void* buffer) {
  base::FilePath path =
      partition_dir_.Append(std::string(partition)).AddExtension("img");

  if (offset < 0) {
    int64_t file_size;
    if (!base::GetFileSize(path, &file_size)) {
      fprintf(stderr, "Error getting size of file '%s'\n",
              path.value().c_str());
      return AVB_IO_RESULT_ERROR_IO;
    }
    offset = file_size - (-offset);
  }

  int fd = open(path.value().c_str(), O_WRONLY);
  if (fd < 0) {
    fprintf(stderr, "Error opening file '%s': %s\n", path.value().c_str(),
            strerror(errno));
    return AVB_IO_RESULT_ERROR_IO;
  }
  if (lseek(fd, offset, SEEK_SET) != offset) {
    fprintf(stderr, "Error seeking to pos %zd in file %s: %s\n", offset,
            path.value().c_str(), strerror(errno));
    close(fd);
    return AVB_IO_RESULT_ERROR_IO;
  }
  ssize_t num_written = write(fd, buffer, num_bytes);
  if (num_written < 0) {
    fprintf(stderr,
            "Error writing %zd bytes at pos %" PRId64 " in file %s: %s\n",
            num_bytes, offset, path.value().c_str(), strerror(errno));
    close(fd);
    return AVB_IO_RESULT_ERROR_IO;
  }
  close(fd);

  return AVB_IO_RESULT_OK;
}

AvbIOResult FakeAvbOps::validate_vbmeta_public_key(
    AvbOps* ops, const uint8_t* public_key_data, size_t public_key_length,
    bool* out_key_is_trusted) {
  if (out_key_is_trusted != NULL) {
    *out_key_is_trusted = (public_key_length == expected_public_key_.size() &&
                           (memcmp(expected_public_key_.c_str(),
                                   public_key_data, public_key_length) == 0));
  }
  return AVB_IO_RESULT_OK;
}

AvbIOResult FakeAvbOps::read_rollback_index(AvbOps* ops,
                                            size_t rollback_index_slot,
                                            uint64_t* out_rollback_index) {
  if (rollback_index_slot >= stored_rollback_indexes_.size()) {
    fprintf(stderr, "No rollback index for slot %zd (has %zd slots).\n",
            rollback_index_slot, stored_rollback_indexes_.size());
    return AVB_IO_RESULT_ERROR_IO;
  }
  *out_rollback_index = stored_rollback_indexes_[rollback_index_slot];
  return AVB_IO_RESULT_OK;
}

AvbIOResult FakeAvbOps::write_rollback_index(AvbOps* ops,
                                             size_t rollback_index_slot,
                                             uint64_t rollback_index) {
  if (rollback_index_slot >= stored_rollback_indexes_.size()) {
    fprintf(stderr, "No rollback index for slot %zd (has %zd slots).\n",
            rollback_index_slot, stored_rollback_indexes_.size());
    return AVB_IO_RESULT_ERROR_IO;
  }
  stored_rollback_indexes_[rollback_index_slot] = rollback_index;
  return AVB_IO_RESULT_OK;
}

AvbIOResult FakeAvbOps::read_is_device_unlocked(AvbOps* ops,
                                                bool* out_is_device_unlocked) {
  *out_is_device_unlocked = stored_is_device_unlocked_ ? 1 : 0;
  return AVB_IO_RESULT_OK;
}

AvbIOResult FakeAvbOps::get_unique_guid_for_partition(AvbOps* ops,
                                                      const char* partition,
                                                      char* guid_buf,
                                                      size_t guid_buf_size) {
  // This is faking it a bit but makes testing easy. It works
  // because avb_slot_verify.c doesn't check that the returned GUID
  // is wellformed.
  snprintf(guid_buf, guid_buf_size, "1234-fake-guid-for:%s", partition);
  return AVB_IO_RESULT_OK;
}

struct FakeAvbOpsC {
  AvbOps parent;
  FakeAvbOps* my_ops;
};

static AvbIOResult my_ops_read_from_partition(AvbOps* ops,
                                              const char* partition,
                                              int64_t offset, size_t num_bytes,
                                              void* buffer,
                                              size_t* out_num_read) {
  return ((FakeAvbOpsC*)ops)
      ->my_ops->read_from_partition(partition, offset, num_bytes, buffer,
                                    out_num_read);
}

static AvbIOResult my_ops_write_to_partition(AvbOps* ops, const char* partition,
                                             int64_t offset, size_t num_bytes,
                                             const void* buffer) {
  return ((FakeAvbOpsC*)ops)
      ->my_ops->write_to_partition(partition, offset, num_bytes, buffer);
}

static AvbIOResult my_ops_validate_vbmeta_public_key(
    AvbOps* ops, const uint8_t* public_key_data, size_t public_key_length,
    bool* out_key_is_trusted) {
  return ((FakeAvbOpsC*)ops)
      ->my_ops->validate_vbmeta_public_key(
          ops, public_key_data, public_key_length, out_key_is_trusted);
}

static AvbIOResult my_ops_read_rollback_index(AvbOps* ops,
                                              size_t rollback_index_slot,
                                              uint64_t* out_rollback_index) {
  return ((FakeAvbOpsC*)ops)
      ->my_ops->read_rollback_index(ops, rollback_index_slot,
                                    out_rollback_index);
}

static AvbIOResult my_ops_write_rollback_index(AvbOps* ops,
                                               size_t rollback_index_slot,
                                               uint64_t rollback_index) {
  return ((FakeAvbOpsC*)ops)
      ->my_ops->write_rollback_index(ops, rollback_index_slot, rollback_index);
}

static AvbIOResult my_ops_read_is_device_unlocked(
    AvbOps* ops, bool* out_is_device_unlocked) {
  return ((FakeAvbOpsC*)ops)
      ->my_ops->read_is_device_unlocked(ops, out_is_device_unlocked);
}

static AvbIOResult my_ops_get_unique_guid_for_partition(AvbOps* ops,
                                                        const char* partition,
                                                        char* guid_buf,
                                                        size_t guid_buf_size) {
  return ((FakeAvbOpsC*)ops)
      ->my_ops->get_unique_guid_for_partition(ops, partition, guid_buf,
                                              guid_buf_size);
}

FakeAvbOps::FakeAvbOps() {
  avb_ops_ = new FakeAvbOpsC;
  avb_ops_->parent.read_from_partition = my_ops_read_from_partition;
  avb_ops_->parent.write_to_partition = my_ops_write_to_partition;
  avb_ops_->parent.validate_vbmeta_public_key =
      my_ops_validate_vbmeta_public_key;
  avb_ops_->parent.read_rollback_index = my_ops_read_rollback_index;
  avb_ops_->parent.write_rollback_index = my_ops_write_rollback_index;
  avb_ops_->parent.read_is_device_unlocked = my_ops_read_is_device_unlocked;
  avb_ops_->parent.get_unique_guid_for_partition =
      my_ops_get_unique_guid_for_partition;
  avb_ops_->my_ops = this;
}

FakeAvbOps::~FakeAvbOps() { delete avb_ops_; }