Update Changelog for v1.1.0

Some service's might provide the Service Certificate as a SignedDrmCertificate instead of a SignedMessage so I added support for supplying such format certificates. I also added support for supplying a DrmCertificate directly, though it's unlikely for a service to provide it raw without a signature like that.

The Service Certificate is now also stored as just the DrmCertificate internally, as it will not be using the signature.

CHANGELOG.md

@@ -5,7 +5,35 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## [1.0.1] - 2021-07-21
+## [1.1.0] - 2022-07-21
+
+### Added
+
+- Added support for setting a Service Certificate in SignedDrmCertificate form as well as raw DrmCertificate form.
+  However, It's unlikely for the service to provide the certificate in raw DrmCertificate form without a signature.
+- Added a CLI command `create-device` to create Widevine Device (`.wvd`) files from RSA PEM/DER Private Keys and
+  Client ID blobs. You can also provide VMP (FileHashes) data which will be merged into the Client ID blob.
+- Added a CLI command `migrate` that uses `Device.migrate()` and `dump()` to migrate older v1 Widevine Device files
+  to v2.
+- Added the v1 Structure of Widevine Devices for migration use.
+- Added `Device.migrate()` class method that effectively loads older format WVD data. You can then use `dumps()` to
+  get back the WVD data in the latest supported format.
+- Added ability to use Privacy mode on the test command.
+
+### Changed
+
+- Set Service Certificates are now stored as the raw underlying DrmCertificate as the signature data is unused by
+  the CDM.
+- Moved all Widevine Device structures under a Structures class.
+- I removed the `send_key_control_nonce` flag from all Structures even though it was technically used.
+  This is because the flag was never used as of this project, and I do not want to take up the flag slot.
+
+### Fixed
+
+- Devices `dump()` function now uses the correct `type_` parameter when building the struct.
+- Fixed release date year of v1.0.0 and v1.0.1 in the changelog.
+
+## [1.0.1] - 2022-07-21
 
 ### Added
 
@@ -24,14 +52,15 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 
-- Cdm's `set_service_certificate()` now correctly raises a DecodeError on Decode Error instead of a ValueError.
+- CDMs `set_service_certificate()` now correctly raises a DecodeError on Decode Error instead of a ValueError.
 - Context Data will now always match to their corresponding License Responses. This fixes an issue where creating
   a second challenge would overwrite the context data of the first challenge. Parsing the first challenge after
   would result in either a key decrypt error, or garbage key data.
 
-## [1.0.0] - 2021-07-20
+## [1.0.0] - 2022-07-20
 
 Initial Release.
 
+[1.1.0]: https://github.com/rlaphoenix/pywidevine/releases/tag/v1.1.0
 [1.0.1]: https://github.com/rlaphoenix/pywidevine/releases/tag/v1.0.1
 [1.0.0]: https://github.com/rlaphoenix/pywidevine/releases/tag/v1.0.0

poetry.lock

@@ -137,6 +137,14 @@ category = "main"
 optional = false
 python-versions = ">=3.7"
 
+[[package]]
+name = "unidecode"
+version = "1.3.4"
+description = "ASCII transliterations of Unicode text"
+category = "main"
+optional = false
+python-versions = ">=3.5"
+
 [[package]]
 name = "urllib3"
 version = "1.26.10"
@@ -165,7 +173,7 @@ testing = ["pytest (>=6)", "pytest-checkdocs (>=2.4)", "pytest-flake8", "pytest-
 [metadata]
 lock-version = "1.1"
 python-versions = ">=3.7,<3.11"
-content-hash = "9c6a76629e0f0a4e98b6c47707899519f930debd70312d2e909eb42f94cd212f"
+content-hash = "0720732d3b990a11e3b35f4604103364ae5654d1ac6e31ead17c03e566a016d0"
 
 [metadata.files]
 certifi = []
@@ -195,5 +203,9 @@ pycryptodome = []
 pymp4 = []
 requests = []
 typing-extensions = []
+unidecode = [
+    {file = "Unidecode-1.3.4-py3-none-any.whl", hash = "sha256:afa04efcdd818a93237574791be9b2817d7077c25a068b00f8cff7baa4e59257"},
+    {file = "Unidecode-1.3.4.tar.gz", hash = "sha256:8e4352fb93d5a735c788110d2e7ac8e8031eb06ccbfe8d324ab71735015f9342"},
+]
 urllib3 = []
 zipp = []

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "poetry.core.masonry.api"
 
 [tool.poetry]
 name = "pywidevine"
-version = "1.0.1"
+version = "1.1.0"
 description = "Widevine CDM (Content Decryption Module) implementation in Python."
 authors = ["rlaphoenix <rlaphoenix@pm.me>"]
 license = "GPL-3.0-only"
@@ -33,6 +33,7 @@ pycryptodome = "^3.15.0"
 click = "^8.1.3"
 requests = "^2.28.1"
 lxml = "^4.9.1"
+Unidecode = "^1.3.4"
 
 [tool.poetry.scripts]
 pywidevine = "pywidevine.main:main"

pywidevine/__init__.py

@@ -1 +1 @@
-__version__ = "1.0.1"
+__version__ = "1.1.0"

pywidevine/cdm.py

@@ -84,10 +84,10 @@ class Cdm:
             self.init_data = PSSH.get_as_box(pssh).init_data
 
         self.session_id = get_random_bytes(16)
-        self.service_certificate: Optional[SignedMessage] = None
+        self.service_certificate: Optional[DrmCertificate] = None
         self.context: dict[bytes, tuple[bytes, bytes]] = {}
 
-    def set_service_certificate(self, certificate: Union[bytes, str]) -> SignedMessage:
+    def set_service_certificate(self, certificate: Union[bytes, str]) -> DrmCertificate:
         """
         Set a Service Privacy Certificate for Privacy Mode. (optional but recommended)
 
@@ -96,7 +96,7 @@ class Cdm:
                 Some services have their own, but most use the common privacy cert,
                 (common_privacy_cert).
 
-        Returns the parsed Signed Message if successful, otherwise raises a DecodeError.
+        Returns the parsed Drm Certificate if successful, otherwise raises a DecodeError.
 
         The Service Certificate is used to encrypt Client IDs in Licenses. This is also
         known as Privacy Mode and may be required for some services or for some devices.
@@ -106,13 +106,48 @@ class Cdm:
             certificate = base64.b64decode(certificate)  # assuming base64
 
         signed_message = SignedMessage()
-        try:
-            signed_message.ParseFromString(certificate)
-        except DecodeError as e:
-            raise DecodeError(f"Could not parse certificate as a Signed Message: {e}")
+        signed_drm_certificate = SignedDrmCertificate()
+        drm_certificate = DrmCertificate()
 
-        self.service_certificate = signed_message
-        return signed_message
+        # Note: A secure CDM would likely reject any Service Certificate that is
+        # not either a SignedMessage or a SignedDrmCertificate. This is because
+        # the DrmCertificate itself is not signed. This CDM does not verify the
+        # signatures as I'm not sure what HMAC key is used. At this stage of the
+        # CDM flow, we wouldn't have any mac_keys, and those might not work for
+        # verifying service certificate signatures (likely not).
+
+        # All these 3 schemas can sort of parse each other in a minimal buggy way,
+        # so we have to parse down the full chain instead of relaying each step
+
+        try:  # SignedMessage input
+            signed_message.ParseFromString(certificate)
+            signed_drm_certificate.ParseFromString(signed_message.msg)
+            if not signed_drm_certificate.drm_certificate:
+                raise DecodeError()
+            drm_certificate.ParseFromString(signed_drm_certificate.drm_certificate)
+            self.service_certificate = drm_certificate
+            return self.service_certificate
+        except DecodeError:
+            pass
+
+        try:  # SignedDrmCertificate input
+            signed_drm_certificate.ParseFromString(certificate)
+            if not signed_drm_certificate.drm_certificate:
+                raise DecodeError()
+            drm_certificate.ParseFromString(signed_drm_certificate.drm_certificate)
+            self.service_certificate = drm_certificate
+            return self.service_certificate
+        except DecodeError:
+            pass
+
+        try:  # DrmCertificate input
+            drm_certificate.ParseFromString(certificate)
+            self.service_certificate = drm_certificate
+            return self.service_certificate
+        except DecodeError:
+            pass
+
+        raise DecodeError("Could not parse certificate as a Service Certificate")
 
     def get_license_challenge(self, type_: LicenseType = LicenseType.STREAMING, privacy_mode: bool = True) -> bytes:
         """
@@ -253,7 +288,7 @@ class Cdm:
     @staticmethod
     def encrypt_client_id(
         client_id: ClientIdentification,
-        service_certificate: Union[SignedMessage, SignedDrmCertificate, DrmCertificate],
+        service_certificate: DrmCertificate,
         key: bytes = None,
         iv: bytes = None
     ) -> EncryptedClientIdentification:
@@ -261,18 +296,8 @@ class Cdm:
         privacy_key = key or get_random_bytes(16)
         privacy_iv = iv or get_random_bytes(16)
 
-        if isinstance(service_certificate, SignedMessage):
-            signed_service_certificate = SignedDrmCertificate()
-            signed_service_certificate.ParseFromString(service_certificate.msg)
-            service_certificate = signed_service_certificate
-
-        if isinstance(service_certificate, SignedDrmCertificate):
-            service_service_drm_certificate = DrmCertificate()
-            service_service_drm_certificate.ParseFromString(service_certificate.drm_certificate)
-            service_certificate = service_service_drm_certificate
-
         if not isinstance(service_certificate, DrmCertificate):
-            raise ValueError(f"Service Certificate is in an unexpected type {service_certificate!r}")
+            raise ValueError(f"Expecting Service Certificate to be a DrmCertificate, not {service_certificate!r}")
 
         enc_client_id = EncryptedClientIdentification()
         enc_client_id.provider_id = service_certificate.provider_id

pywidevine/device.py

@@ -1,13 +1,14 @@
 from __future__ import annotations
 
 import base64
+import logging
 from enum import Enum
 from pathlib import Path
 from typing import Any, Optional, Union
 
-from construct import BitStruct, Bytes, Const
+from construct import BitStruct, Bytes, Const, ConstructError, Container
 from construct import Enum as CEnum
-from construct import Flag, Int8ub, Int16ub
+from construct import Int8ub, Int16ub
 from construct import Optional as COptional
 from construct import Padded, Padding, Struct, this
 from Crypto.PublicKey import RSA
@@ -21,12 +22,16 @@ class _Types(Enum):
     ANDROID = 2
 
 
-class Device:
-    # needed so bin_format can enumerate the types
-    Types = _Types
+class _Structures:
+    magic = Const(b"WVD")
 
-    bin_format = Struct(
-        "signature" / Const(b"WVD"),
+    header = Struct(
+        "signature" / magic,
+        "version" / Int8ub
+    )
+
+    v2 = Struct(
+        "signature" / magic,
         "version" / Const(Int8ub, 2),
         "type_" / CEnum(
             Int8ub,
@@ -34,8 +39,8 @@ class Device:
         ),
         "security_level" / Int8ub,
         "flags" / Padded(1, COptional(BitStruct(
-            Padding(7),
-            "send_key_control_nonce" / Flag  # deprecated, do not use
+            # no per-device flags yet
+            Padding(8)
         ))),
         "private_key_len" / Int16ub,
         "private_key" / Bytes(this.private_key_len),
@@ -43,6 +48,32 @@ class Device:
         "client_id" / Bytes(this.client_id_len)
     )
 
+    v1 = Struct(
+        "signature" / magic,
+        "version" / Const(Int8ub, 1),
+        "type_" / CEnum(
+            Int8ub,
+            **{t.name: t.value for t in _Types}
+        ),
+        "security_level" / Int8ub,
+        "flags" / Padded(1, COptional(BitStruct(
+            # no per-device flags yet
+            Padding(8)
+        ))),
+        "private_key_len" / Int16ub,
+        "private_key" / Bytes(this.private_key_len),
+        "client_id_len" / Int16ub,
+        "client_id" / Bytes(this.client_id_len),
+        "vmp_len" / Int16ub,
+        "vmp" / Bytes(this.vmp_len)
+    )
+
+
+class Device:
+    Types = _Types
+    Structures = _Structures
+    supported_structure = Structures.v2
+
     # == Bin Format Revisions == #
     # Version 2: Removed vmp and vmp_len as it should already be within the Client ID
     # Version 1: Removed system_id as it can be retrieved from the Client ID's DRM Certificate
@@ -109,20 +140,20 @@ class Device:
             data = base64.b64decode(data)
         if not isinstance(data, bytes):
             raise ValueError(f"Expecting Bytes or Base64 input, got {data!r}")
-        return cls(**cls.bin_format.parse(data))
+        return cls(**cls.supported_structure.parse(data))
 
     @classmethod
     def load(cls, path: Union[Path, str]) -> Device:
         if not isinstance(path, (Path, str)):
             raise ValueError(f"Expecting Path object or path string, got {path!r}")
         with Path(path).open(mode="rb") as f:
-            return cls(**cls.bin_format.parse_stream(f))
+            return cls(**cls.supported_structure.parse_stream(f))
 
     def dumps(self) -> bytes:
         private_key = self.private_key.export_key("DER") if self.private_key else None
-        return self.bin_format.build(dict(
+        return self.supported_structure.build(dict(
             version=2,
-            type=self.type.value,
+            type_=self.type.value,
             security_level=self.security_level,
             flags=self.flags,
             private_key_len=len(private_key) if private_key else 0,
@@ -138,5 +169,54 @@ class Device:
         path.parent.mkdir(parents=True, exist_ok=True)
         path.write_bytes(self.dumps())
 
+    @classmethod
+    def migrate(cls, data: Union[bytes, str]) -> Device:
+        if isinstance(data, str):
+            data = base64.b64decode(data)
+        if not isinstance(data, bytes):
+            raise ValueError(f"Expecting Bytes or Base64 input, got {data!r}")
+
+        header = _Structures.header.parse(data)
+        if header.version == 2:
+            raise ValueError("Device Data is already migrated to the latest version.")
+        if header.version == 0 or header.version > 2:
+            # we have never used version 0, likely data that just so happened to use the WVD magic
+            raise ValueError("Device Data does not seem to be a WVD file (v0).")
+
+        if header.version == 1:  # v1 to v2
+            data = _Structures.v1.parse(data)
+            data.version = 2  # update version to 2 to allow loading
+            data.flags = Container()  # blank flags that may have been used in v1
+
+            vmp = FileHashes()
+            if data.vmp:
+                try:
+                    vmp.ParseFromString(data.vmp)
+                except DecodeError as e:
+                    raise DecodeError(f"Failed to parse VMP data as FileHashes, {e}")
+                data.vmp = vmp
+
+                client_id = ClientIdentification()
+                try:
+                    client_id.ParseFromString(data.client_id)
+                except DecodeError as e:
+                    raise DecodeError(f"Failed to parse VMP data as FileHashes, {e}")
+
+                new_vmp_data = data.vmp.SerializeToString()
+                if client_id.vmp_data and client_id.vmp_data != new_vmp_data:
+                    logging.getLogger("migrate").warning("Client ID already has Verified Media Path data")
+                client_id.vmp_data = new_vmp_data
+                data.client_id = client_id.SerializeToString()
+
+            try:
+                data = _Structures.v2.build(data)
+            except ConstructError as e:
+                raise ValueError(f"Migration failed, {e}")
+
+        try:
+            return cls.loads(data)
+        except ConstructError as e:
+            raise ValueError(f"Device Data seems to be corrupt or invalid, or migration failed, {e}")
+
 
 __ALL__ = (Device,)

pywidevine/main.py

@@ -1,14 +1,18 @@
 import logging
 from datetime import datetime
 from pathlib import Path
+from typing import Optional
+from zlib import crc32
 
 import click
 import requests
+from construct import ConstructError
+from unidecode import unidecode, UnidecodeError
 
 from pywidevine import __version__
 from pywidevine.cdm import Cdm
 from pywidevine.device import Device
-from pywidevine.license_protocol_pb2 import LicenseType
+from pywidevine.license_protocol_pb2 import LicenseType, FileHashes
 
 
 @click.group(invoke_without_command=True)
@@ -113,8 +117,10 @@ def license_(device: Path, pssh: str, server: str, type_: str, raw: bool, privac
 
 @main.command()
 @click.argument("device", type=Path)
+@click.option("-p", "--privacy", is_flag=True, default=False,
+              help="Use Privacy Mode, off by default.")
 @click.pass_context
-def test(ctx: click.Context, device: Path):
+def test(ctx: click.Context, device: Path, privacy: bool):
     """
     Test the CDM code by getting Content Keys for Bitmovin's Art of Motion example.
     https://bitmovin.com/demos/drm
@@ -148,5 +154,108 @@ def test(ctx: click.Context, device: Path):
         pssh=pssh,
         server=license_server,
         type_=LicenseType.Name(license_type),
-        raw=raw
+        raw=raw,
+        privacy=privacy
     )
+
+
+@main.command()
+@click.option("-t", "--type", "type_", type=click.Choice([x.name for x in Device.Types], case_sensitive=False),
+              required=True, help="Device Type")
+@click.option("-l", "--level", type=click.IntRange(1, 3), required=True, help="Device Security Level")
+@click.option("-k", "--key", type=Path, required=True, help="Device RSA Private Key in PEM or DER format")
+@click.option("-c", "--client_id", type=Path, required=True, help="Widevine ClientIdentification Blob file")
+@click.option("-v", "--vmp", type=Path, required=True, help="Widevine FileHashes Blob file")
+@click.option("-o", "--output", type=Path, default=None, help="Output Directory")
+@click.pass_context
+def create_device(
+    ctx: click.Context,
+    type_: str,
+    level: int,
+    key: Path,
+    client_id: Path,
+    vmp: Optional[Path] = None,
+    output: Optional[Path] = None
+) -> None:
+    """
+    Create a Widevine Device (.wvd) file from an RSA Private Key (PEM or DER) and Client ID Blob.
+    Optionally also a VMP (Verified Media Path) Blob, which will be stored in the Client ID.
+    """
+    if not key.is_file():
+        raise click.UsageError("key: Not a path to a file, or it doesn't exist.", ctx)
+    if not client_id.is_file():
+        raise click.UsageError("client_id: Not a path to a file, or it doesn't exist.", ctx)
+    if vmp and not vmp.is_file():
+        raise click.UsageError("vmp: Not a path to a file, or it doesn't exist.", ctx)
+
+    log = logging.getLogger("create-device")
+
+    device = Device(
+        type_=Device.Types[type_.upper()],
+        security_level=level,
+        flags=None,
+        private_key=key.read_bytes(),
+        client_id=client_id.read_bytes()
+    )
+
+    if vmp:
+        new_vmp_data = vmp.read_bytes()
+        if device.client_id.vmp_data and device.client_id.vmp_data != new_vmp_data:
+            log.warning("Client ID already has Verified Media Path data")
+        device.client_id.vmp_data = new_vmp_data
+
+    client_info = {}
+    for entry in device.client_id.client_info:
+        client_info[entry.name] = entry.value
+
+    wvd_bin = device.dumps()
+
+    name = f"{client_info['company_name']} {client_info['model_name']}"
+    if client_info.get("widevine_cdm_version"):
+        name += f" {client_info['widevine_cdm_version']}"
+    name += f" {crc32(wvd_bin).to_bytes(4, 'big').hex()}"
+
+    try:
+        name = unidecode(name.strip().lower().replace(" ", "_"))
+    except UnidecodeError as e:
+        raise click.ClickException(f"Failed to sanitize name, {e}")
+
+    out_path = (output or Path.cwd()) / f"{name}_{device.system_id}_l{device.security_level}.wvd"
+    out_path.write_bytes(wvd_bin)
+
+    log.info(f"Created Widevine Device (.wvd) file, {out_path.name}")
+    log.info(f" + Type: {device.type.name}")
+    log.info(f" + System ID: {device.system_id}")
+    log.info(f" + Security Level: {device.security_level}")
+    log.info(f" + Flags: {device.flags}")
+    log.info(f" + Private Key: {bool(device.private_key)} ({device.private_key.size_in_bits()} bit)")
+    log.info(f" + Client ID: {bool(device.client_id)} ({len(device.client_id.SerializeToString())} bytes)")
+    if device.client_id.vmp_data:
+        file_hashes_ = FileHashes()
+        file_hashes_.ParseFromString(device.client_id.vmp_data)
+        log.info(f" + VMP: True ({len(file_hashes_.signatures)} signatures)")
+    else:
+        log.info(f" + VMP: False")
+    log.info(f" + Saved to: {out_path.absolute()}")
+
+
+@main.command()
+@click.argument("device", type=Path)
+@click.pass_context
+def migrate(ctx: click.Context, device: Path) -> None:
+    """Upgrade from earlier versions of the Widevine Device (.wvd) format."""
+    if not device.is_file():
+        raise click.UsageError("device: Not a path to a file, or it doesn't exist.", ctx)
+
+    log = logging.getLogger("migrate")
+
+    try:
+        new_device = Device.migrate(device.read_bytes())
+    except (ConstructError, ValueError) as e:
+        raise click.UsageError(str(e), ctx)
+
+    # save
+    log.debug(new_device)
+    new_device.dump(device)
+
+    log.info("Successfully migrated the Widevine Device (.wvd) file!")