Import extract_android_ota_payload

From cyxx/extract_android_ota_payload#8
Commit 254cbdc9825056fd6ac49aea5a4fc9bcefe0b3d0
"Support selective extraction of partitions"

Signed-off-by: spezi77 <[email protected]>

scripts/extract_android_ota_payload/.gitignore

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+*.pyc

scripts/extract_android_ota_payload/README.md

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+# extract_android_ota_payload.py
+
+Extract Android firmware images from an OTA payload.bin file.
+
+With the introduction of the A/B system update, the OTA file format changed.
+This tool allows to extract and decompress the firmware images packed using the 'brillo' toolset.
+
+Incremental firmware images are not supported (source_copy, source_bsdiff operations).
+
+## Usage
+
+```
+$ extract_android_ota_payload.py <payload.bin> [target_dir] [partition.img]
+  <payload.bin>   : file extracted from the OTA zip file or the OTA zip file
+  <target_dir>    : output directory for the extracted file
+  <partition_img> : name of partition to be extracted
+```
+
+## Example
+
+```
+$ python extract_android_ota_payload.py marlin-ota-opm4.171019.021.d1-fd6998a5.zip /tmp/
+Extracting 'boot.img'
+Extracting 'system.img'
+Extracting 'vendor.img'
+...
+Extracting 'modem.img'
+```
+
+## Dependencies
+
+```
+python-protobuf
+```

scripts/extract_android_ota_payload/extract_android_ota_payload.py

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+#!/usr/bin/env python
+
+import hashlib
+import os
+import os.path
+import shutil
+import struct
+import subprocess
+import sys
+import zipfile
+
+# protobufs compiled with protoc 2.5.0 are not compatible with python3
+if sys.version_info[0] != 2:
+  raise Exception("Python 2.x is required")
+
+# from https://android.googlesource.com/platform/system/update_engine/+/refs/heads/master/scripts/update_payload/
+import update_metadata_pb2
+
+PROGRAMS = [ 'bzcat', 'xzcat' ]
+
+BRILLO_MAJOR_PAYLOAD_VERSION = 2
+
+class PayloadError(Exception):
+  pass
+
+class Payload(object):
+  class _PayloadHeader(object):
+    _MAGIC = 'CrAU'
+
+    def __init__(self):
+      self.version = None
+      self.manifest_len = None
+      self.metadata_signature_len = None
+      self.size = None
+
+    def ReadFromPayload(self, payload_file):
+      magic = payload_file.read(4)
+      if magic != self._MAGIC:
+        raise PayloadError('Invalid payload magic: %s' % magic)
+      self.version = struct.unpack('>Q', payload_file.read(8))[0]
+      self.manifest_len = struct.unpack('>Q', payload_file.read(8))[0]
+      self.size = 20
+      self.metadata_signature_len = 0
+      if self.version != BRILLO_MAJOR_PAYLOAD_VERSION:
+        raise PayloadError('Unsupported payload version (%d)' % self.version)
+      self.size += 4
+      self.metadata_signature_len = struct.unpack('>I', payload_file.read(4))[0]
+
+  def __init__(self, payload_file):
+    self.payload_file = payload_file
+    self.header = None
+    self.manifest = None
+    self.data_offset = None
+    self.metadata_signature = None
+    self.metadata_size = None
+
+  def _ReadManifest(self):
+    return self.payload_file.read(self.header.manifest_len)
+
+  def _ReadMetadataSignature(self):
+    self.payload_file.seek(self.header.size + self.header.manifest_len)
+    return self.payload_file.read(self.header.metadata_signature_len);
+
+  def ReadDataBlob(self, offset, length):
+    self.payload_file.seek(self.data_offset + offset)
+    return self.payload_file.read(length)
+
+  def Init(self):
+    self.header = self._PayloadHeader()
+    self.header.ReadFromPayload(self.payload_file)
+    manifest_raw = self._ReadManifest()
+    self.manifest = update_metadata_pb2.DeltaArchiveManifest()
+    self.manifest.ParseFromString(manifest_raw)
+    metadata_signature_raw = self._ReadMetadataSignature()
+    if metadata_signature_raw:
+      self.metadata_signature = update_metadata_pb2.Signatures()
+      self.metadata_signature.ParseFromString(metadata_signature_raw)
+    self.metadata_size = self.header.size + self.header.manifest_len
+    self.data_offset = self.metadata_size + self.header.metadata_signature_len
+
+def decompress_payload(command, data, size, hash):
+  p = subprocess.Popen([command, '-'], stdout=subprocess.PIPE, stdin=subprocess.PIPE)
+  r = p.communicate(data)[0]
+  if len(r) != size:
+    print("Unexpected size %d %d" % (len(r), size))
+  elif hashlib.sha256(data).digest() != hash:
+    print("Hash mismatch")
+  return r
+
+def parse_payload(payload_f, partition, out_f):
+  BLOCK_SIZE = 4096
+  for operation in partition.operations:
+    e = operation.dst_extents[0]
+    data = payload_f.ReadDataBlob(operation.data_offset, operation.data_length)
+    out_f.seek(e.start_block * BLOCK_SIZE)
+    if operation.type == update_metadata_pb2.InstallOperation.REPLACE:
+      out_f.write(data)
+    elif operation.type == update_metadata_pb2.InstallOperation.REPLACE_XZ:
+      r = decompress_payload('xzcat', data, e.num_blocks * BLOCK_SIZE, operation.data_sha256_hash)
+      out_f.write(r)
+    elif operation.type == update_metadata_pb2.InstallOperation.REPLACE_BZ:
+      r = decompress_payload('bzcat', data, e.num_blocks * BLOCK_SIZE, operation.data_sha256_hash)
+      out_f.write(r)
+    else:
+      raise PayloadError('Unhandled operation type (%d)' % operation.type)
+
+def main(filename, output_dir, partition):
+  if filename.endswith('.zip'):
+    print("Extracting 'payload.bin' from OTA file...")
+    ota_zf = zipfile.ZipFile(filename)
+    payload_file = open(ota_zf.extract('payload.bin', output_dir))
+  else:
+    payload_file = file(filename)
+
+  payload = Payload(payload_file)
+  payload.Init()
+
+  for p in payload.manifest.partitions:
+    name = p.partition_name + '.img'
+    if (partition is not None and name != partition):
+      continue
+    print("Extracting '%s'" % name)
+    fname = os.path.join(output_dir, name)
+    out_f = open(fname, 'w')
+    try:
+      parse_payload(payload, p, out_f)
+    except PayloadError as e:
+      print('Failed: %s' % e)
+      out_f.close()
+      os.unlink(fname)
+
+if __name__ == '__main__':
+  try:
+    filename = sys.argv[1]
+  except:
+    print('Usage: %s payload.bin [output_dir] [partition.img]' % sys.argv[0])
+    sys.exit()
+
+  try:
+    output_dir = sys.argv[2]
+  except IndexError:
+    output_dir = os.getcwd()
+
+  try:
+    partition = sys.argv[3]
+  except IndexError:
+    try:
+      partition = sys.argv[2]
+    except IndexError:
+      partition = None
+
+  if partition is not None and not partition.endswith('.img'):
+    partition = None
+
+  if output_dir.endswith('.img'):
+    output_dir = os.getcwd()
+
+  if not os.path.exists(output_dir):
+    os.makedirs(output_dir)
+
+  main(filename, output_dir, partition)

scripts/extract_android_ota_payload/requirements.txt

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+protobuf>=2.5.0