README for Widevine CDM Partner Kit v2.1
Date: 6/03/2014
This document provides additional details on installation, system
setup, building, and testing components of the Widevine Content
Decryption Module supplied in the Widevine CDM Partner Kit.
This document supplements the information found in the "WV Modular DRM
Security Integration Guide for Common Encryption (CENC): EME/Embedded
Device Supplement v2.1", which is the EME-specific portion of the
dcoeument "WV Modular DRM Security Integration Guide for Common
Encryption (CENC)".
Kit Contents
The Widevine CDM Partner Kit is distributed as an XZipped tar file
(.tar.xz). To unpack the kit into your current working directory:
tar xf widevine-cdm_<kit-version>.tar.xz
cd widevine-cdm_<kit-version>
The remaining instructions will refer to this directory as <cdm-kit-dir>.
The top level directories and files of the kit are as follows:
cdm - the CDM interface declarations and definitions, and tests
core - the CDM implementation, and tests
linux - platform-specific files for the CDM implementation
oemcrypto - OEMCrypto declarations, a mock implementation, and tests
platforms - platform-specific build configs
README - this file
run_test.sh - builds and tests the CDM with mock OEMCrypto
System Setup
Some third-party software packages are required to build the CDM, OEMCrypto,
and various test modules. The actual versions that have been used and
verified are listed here, but earlier or later versions may also work. If
you already have a different version of a particular package installed
on your system, then you should try the build and unit tests to see if
there are any issues.
The current set of third-party packages includes:
- gTest and gMock (version 1.6.0)
- protobufs (Google Protocol Buffers) (version 2.5)
- OpenSSL (libssl and libcrypto) (version 1.0.1g)
- stringencoders (https://code.google.com/p/stringencoders)
- python (version 2.7 or better)
- GYP (python-based build tool) (https://code.google.com/p/gyp,
svn revision 1846)
The following sections provide information about acquiring
and installing some of these packages. This is not a complete list, but
it tries to cover the items that do not follow the typical methodologies.
Also, the instructions apply to and were tested on an up-to-date Ubuntu
system. They may not work on your system exactly as shown.
GYP
The kit uses GYP (Generate Your Projects) to create makefiles.
The standard GYP source release is through a subversion (svn) checkout
of trunk. Most of this kit's development and testing was performed with
GYP revision 1846. The newest revision at the time of this document
is 1884. You may already have GYP installed on your system, or you may
try "apt-get install gyp" to install the version packaged for your
system. If you choose to install the latest revision (option 1) or install
revision 1846 (option 2), follow the instructions below.
GYP requires Python. You should already have python 2.7 or better on your
system. There is also a python package called setuptools that GYP requires.
If the GYP build fails, see the section below to install setuptools.
python --version # will return "Python 2.7.3" or something similar
mkdir <gyp-kit-root>
cd <gyp-kit-root>
# checkout latest GYP (option 1)
svn checkout http://gyp.googlecode.com/svn/trunk/ gyp-read-only
# checkout GYP revision 1846 (option 2)
svn checkout http://gyp.googlecode.com/svn/trunk/ gyp-read-only -r1846
cd gyp-read-only/
./setup.py build # this will fail if setuptools is not installed
sudo ./setup.py install
Python setuptools
Do this if the "setup.py build" fails.
mkdir <setuptools-temp>
cd <setuptools-temp>
wget https://bitbucket.org/pypa/setuptools/raw/bootstrap/ez_setup.py \
-O - | sudo python
Return to the GYP installation.
Google Protocol Buffers (protobufs)
The following instructions will install the protobuf compiler and libraries
in /usr. The default installation directory is /usr/local, which you may
also use, but you should make sure that an older version is not installed
in /usr.
protoc --version # test whether protobufs already on system
which protoc # where is it installed?
mkdir <protobuf-kit-root>
cd <protobuf-kit-root>
wget http://protobuf.googlecode.com/files/protobuf-2.5.0.tar.gz
tar xzf protobuf-2.5.0.tar.gz
cd protobuf-2.5.0/
./configure --prefix=/usr --exec-prefix=/usr
make
sudo make install
protoc --version
The final command should return: libprotoc 2.5.0
Google C++ Mocking Framework (gmock and gtest)
The following instructions will install the Google Mock and
Google Test frameworks. The package can exist anywhere on
the build system. The kit uses gmock-1.6.0.zip and can be
downloaded from https://code.google.com/p/googlemock/downloads/list.
mkdir <gmock_dir>
cd <gmock_dir>
wget https://googlemock.googlecode.com/files/gmock-1.6.0.zip
unzip gmock-1.6.0.zip
cd <cdm-kit-dir>
mkdir third_party
cd third_party
ln -sf <gmock_dir>/gmock-1.6.0 gmock
The kit build will use the symlink when building the unit tests.
StringEncoders 3.10.3 (stringencoders)
The following instructions will install and configure the
stringencoders package. After configuring and building the
package, several files must be copied to the kit.
The kit uses stringencoders-v3.10.3.tar.gz which can be downloaded from
https://code.google.com/p/stringencoders/downloads/list.
mkdir <stringencoders-dir>
cd <stringencoders-dir>
wget \
https://stringencoders.googlecode.com/files/stringencoders-v3.10.3.tar.gz
tar xzvf stringencoders-v3.10.3.tar.gz
cd stringencoders-v3.10.3
./configure --with-b64wchars='-_=' CFLAGS=-Wno-unused-but-set-variable
make
mkdir -p <cdm-kit-dir>/third_party/stringencoders/src
cp modp_b64w_data.h <cdm-kit-dir>/third_party/stringencoders/src
cp src/modp_b64w.c \
<cdm-kit-dir>/third_party/stringencoders/src/modp_b64w.cpp
cp src/modp_b64w.h <cdm-kit-dir>/third_party/stringencoders/src
Note that the file extension of the source is changed from .c to .cpp.
The final step will be to edit
<cdm-kit-dir>/third_party/stringencoders/src/modp_b64w.cpp
and comment out the line '#include "config.h"'.
What's in the kit?
The kit contains two major components and a small suite of unit tests:
a Widevine CDM and a Mock OEMCrypto. These components will enable you
to create an OEMCrypto library and a CDM module for your target devices.
The CDM relies on OEMCrypto for performing secure operations. The Mock
OEMCrypto uses OpenSSL to perform all OEMCrypto functions. This library
is *NOT* secure and it *CANNOT* be used in a production environment, but
it allows you to verify your CDM port before you have a working OEMCrypto
for your device, plus it provides a reference implementation to help you
implement and verify your OEMCrypto.
The CDM uses a "Host" interface to communicate with the upper layers of
the system and also to obtain certain services it needs, such as timers
and file I/O support. This kit contains a simple implementation of the
Host interface. You will create a complete Host interface for each of
your target devices.
Building components
The easiest way to build is to navigate to the top level directory of
the installed kit and run the following script. This does a full build
of the linux target and runs wvcdm_shared_api_unittest:
./run_test.sh
The top-level build script is build.py. It configures the build
environment, runs GYP to generate a series of make files. and starts the
top level make. The build scripts are parameterized to build for multiple
targets. All the pieces are provided to build for x86-64 (linux). You
can use the x86-64 build as a template for building for your embedded targets.
The "CDM Porting Guide" supplied with this kit discusses the steps involved.
Configuring for a new target device
The kit "out of the box" builds a CDM module and links it into a unit
test executable image that can be run on your linux system. To build
the CDM for a different target device, you will have to install an appropriate
toolchain and SDK for your targets. Then you will have to extend
the build scripts to utilize these resources. You will also have to modify
or add certain source modules to integrate the CDM into your target's
media and/or browser environment. This process is documented in the
"CDM Porting Guide".
Tests
Read the sections related to testing in the "WV Modular DRM Security
Integration Guide for Common Encryption (CENC): EME/Embedded Device
Supplement v2.1"
Test directories can be found in many of the kit's directories. The GYP files
for building the test images are found in the test directory or one level
above the test directory. The test-releated GYP targets will have "test" or
"unittest" in the name.
Here's a current list of GYP files and test-related targets:
File - Targets Purpose
cdm/cdm.gyp
license_protocol Create protobuf sources for license protocol
device_files Create protobuf sources for license storage
wvcdm_sysdep Build system-dependent layer of CDM
wvcdm_shared Build CDM shared library
cdm/cdm_unittests.gyp
wvcdm_shared_api_unittest Build CDM unit tests
cdm/test/gtest.gyp
gtest Provides gtest modules for unit tests
cdm/test/gmock.gyp
gmock Provides gmock modules for unit tests
gmock_main Provides main routine for unit tests
oemcrypto/mock/oec_mock.gyp
oemcrypto Top level target to build/link OEMCrypto
oemcrypto/oemcrypto.gyp
oec_lib Build OEMCrypto library
oec_mock Build mock OEMCrypto library
oec_unittest Build OEMCrypto unit tests
oemcrypto/mock/oec_mock.gyp
oec_mock Build mock OEMCrypto sources
oemcrypto/prebuilt/oec_prebuilt.gyp
oec_prebuilt Integrate prebuilt OEMCrypto library
The "CDM Porting Guide" discusses how these targets are used and how you
will modify them to build libraries and test binaries for your target devices.
The "CDM Porting Guide", the "WV Modular DRM Security Integration Guide for
Common Encryption (CENC): EME/Embedded Device Supplement v2.1", and the
"WV Modular DRM Security Integration Guide for Common Encryption (CENC)"
should provide the information you need to create your OEMCrypto and CDM
implementations for your target devices.