tools/releasetools/test_verity_utils.py

#
# Copyright (C) 2018 The Android Open Source Project
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#

"""Unittests for verity_utils.py."""

import math
import os.path
import random

import common
import sparse_img
from rangelib import RangeSet
from test_utils import get_testdata_dir, ReleaseToolsTestCase
from verity_utils import (
    CreateHashtreeInfoGenerator, CreateVerityImageBuilder, HashtreeInfo,
    VerifiedBootVersion1HashtreeInfoGenerator)

BLOCK_SIZE = common.BLOCK_SIZE


class VerifiedBootVersion1HashtreeInfoGeneratorTest(ReleaseToolsTestCase):

  def setUp(self):
    self.testdata_dir = get_testdata_dir()

    self.partition_size = 1024 * 1024
    self.prop_dict = {
        'verity': 'true',
        'verity_fec': 'true',
        'system_verity_block_device': '/dev/block/system',
        'system_size': self.partition_size
    }

    self.hash_algorithm = "sha256"
    self.fixed_salt = \
        "aee087a5be3b982978c923f566a94613496b417f2af592639bc80d141e34dfe7"
    self.expected_root_hash = \
        "0b7c4565e87b1026e11fbab91c0bc29e185c847a5b44d40e6e86e461e8adf80d"

  def _create_simg(self, raw_data):
    output_file = common.MakeTempFile()
    raw_image = common.MakeTempFile()
    with open(raw_image, 'wb') as f:
      f.write(raw_data)

    cmd = ["img2simg", raw_image, output_file, '4096']
    p = common.Run(cmd)
    p.communicate()
    self.assertEqual(0, p.returncode)

    return output_file

  def _generate_image(self):
    partition_size = 1024 * 1024
    prop_dict = {
        'partition_size': str(partition_size),
        'verity': 'true',
        'verity_block_device': '/dev/block/system',
        'verity_key': os.path.join(self.testdata_dir, 'testkey'),
        'verity_fec': 'true',
        'verity_signer_cmd': 'verity_signer',
    }
    verity_image_builder = CreateVerityImageBuilder(prop_dict)
    self.assertIsNotNone(verity_image_builder)
    adjusted_size = verity_image_builder.CalculateMaxImageSize()

    raw_image = ""
    for i in range(adjusted_size):
      raw_image += str(i % 10)

    output_file = self._create_simg(raw_image)

    # Append the verity metadata.
    verity_image_builder.Build(output_file)

    return output_file

  def test_CreateHashtreeInfoGenerator(self):
    image_file = sparse_img.SparseImage(self._generate_image())

    generator = CreateHashtreeInfoGenerator(
        'system', image_file, self.prop_dict)
    self.assertEqual(
        VerifiedBootVersion1HashtreeInfoGenerator, type(generator))
    self.assertEqual(self.partition_size, generator.partition_size)
    self.assertTrue(generator.fec_supported)

  def test_DecomposeSparseImage(self):
    image_file = sparse_img.SparseImage(self._generate_image())

    generator = VerifiedBootVersion1HashtreeInfoGenerator(
        self.partition_size, 4096, True)
    generator.DecomposeSparseImage(image_file)
    self.assertEqual(991232, generator.filesystem_size)
    self.assertEqual(12288, generator.hashtree_size)
    self.assertEqual(32768, generator.metadata_size)

  def test_ParseHashtreeMetadata(self):
    image_file = sparse_img.SparseImage(self._generate_image())
    generator = VerifiedBootVersion1HashtreeInfoGenerator(
        self.partition_size, 4096, True)
    generator.DecomposeSparseImage(image_file)

    # pylint: disable=protected-access
    generator._ParseHashtreeMetadata()

    self.assertEqual(
        self.hash_algorithm, generator.hashtree_info.hash_algorithm)
    self.assertEqual(self.fixed_salt, generator.hashtree_info.salt)
    self.assertEqual(self.expected_root_hash, generator.hashtree_info.root_hash)

  def test_ValidateHashtree_smoke(self):
    generator = VerifiedBootVersion1HashtreeInfoGenerator(
        self.partition_size, 4096, True)
    generator.image = sparse_img.SparseImage(self._generate_image())

    generator.hashtree_info = info = HashtreeInfo()
    info.filesystem_range = RangeSet(data=[0, 991232 / 4096])
    info.hashtree_range = RangeSet(
        data=[991232 / 4096, (991232 + 12288) / 4096])
    info.hash_algorithm = self.hash_algorithm
    info.salt = self.fixed_salt
    info.root_hash = self.expected_root_hash

    self.assertTrue(generator.ValidateHashtree())

  def test_ValidateHashtree_failure(self):
    generator = VerifiedBootVersion1HashtreeInfoGenerator(
        self.partition_size, 4096, True)
    generator.image = sparse_img.SparseImage(self._generate_image())

    generator.hashtree_info = info = HashtreeInfo()
    info.filesystem_range = RangeSet(data=[0, 991232 / 4096])
    info.hashtree_range = RangeSet(
        data=[991232 / 4096, (991232 + 12288) / 4096])
    info.hash_algorithm = self.hash_algorithm
    info.salt = self.fixed_salt
    info.root_hash = "a" + self.expected_root_hash[1:]

    self.assertFalse(generator.ValidateHashtree())

  def test_Generate(self):
    image_file = sparse_img.SparseImage(self._generate_image())
    generator = CreateHashtreeInfoGenerator('system', 4096, self.prop_dict)
    info = generator.Generate(image_file)

    self.assertEqual(RangeSet(data=[0, 991232 / 4096]), info.filesystem_range)
    self.assertEqual(RangeSet(data=[991232 / 4096, (991232 + 12288) / 4096]),
                     info.hashtree_range)
    self.assertEqual(self.hash_algorithm, info.hash_algorithm)
    self.assertEqual(self.fixed_salt, info.salt)
    self.assertEqual(self.expected_root_hash, info.root_hash)


class VerifiedBootVersion2VerityImageBuilderTest(ReleaseToolsTestCase):

  def setUp(self):
    # To test CalculateMinPartitionSize(), by using 200MB to 2GB image size.
    #   -  51200 = 200MB * 1024 * 1024 / 4096
    #   - 524288 = 2GB * 1024 * 1024 * 1024 / 4096
    self._image_sizes = [BLOCK_SIZE * random.randint(51200, 524288) + offset
                         for offset in range(BLOCK_SIZE)]

    prop_dict = {
        'partition_size': None,
        'partition_name': 'system',
        'avb_avbtool': 'avbtool',
        'avb_hashtree_enable': 'true',
        'avb_add_hashtree_footer_args': None,
    }
    self.builder = CreateVerityImageBuilder(prop_dict)
    self.assertEqual(2, self.builder.version)

  def test_CalculateMinPartitionSize_LinearFooterSize(self):
    """Tests with footer size which is linear to partition size."""
    for image_size in self._image_sizes:
      for ratio in 0.95, 0.56, 0.22:
        expected_size = common.RoundUpTo4K(int(math.ceil(image_size / ratio)))
        self.assertEqual(
            expected_size,
            self.builder.CalculateMinPartitionSize(
                image_size, lambda x, ratio=ratio: int(x * ratio)))

  def test_AVBCalcMinPartitionSize_SlowerGrowthFooterSize(self):
    """Tests with footer size which grows slower than partition size."""

    def _SizeCalculator(partition_size):
      """Footer size is the power of 0.95 of partition size."""
      # Minus footer size to return max image size.
      return partition_size - int(math.pow(partition_size, 0.95))

    for image_size in self._image_sizes:
      min_partition_size = self.builder.CalculateMinPartitionSize(
          image_size, _SizeCalculator)
      # Checks min_partition_size can accommodate image_size.
      self.assertGreaterEqual(
          _SizeCalculator(min_partition_size),
          image_size)
      # Checks min_partition_size (round to BLOCK_SIZE) is the minimum.
      self.assertLess(
          _SizeCalculator(min_partition_size - BLOCK_SIZE),
          image_size)

  def test_CalculateMinPartitionSize_FasterGrowthFooterSize(self):
    """Tests with footer size which grows faster than partition size."""

    def _SizeCalculator(partition_size):
      """Max image size is the power of 0.95 of partition size."""
      # Max image size grows less than partition size, which means
      # footer size grows faster than partition size.
      return int(math.pow(partition_size, 0.95))

    for image_size in self._image_sizes:
      min_partition_size = self.builder.CalculateMinPartitionSize(
          image_size, _SizeCalculator)
      # Checks min_partition_size can accommodate image_size.
      self.assertGreaterEqual(
          _SizeCalculator(min_partition_size),
          image_size)
      # Checks min_partition_size (round to BLOCK_SIZE) is the minimum.
      self.assertLess(
          _SizeCalculator(min_partition_size - BLOCK_SIZE),
          image_size)