ea539673a4
Cherry pick of http://go/ag/9326830 This is a merge of the full decrypt path testing CLs from the Widevine repo: http://go/wvgerrit/q/topic:FDPT-subsamples This is the Full Decrypt Path Testing application that can be used by device makers to verify that OEMCrypto is correctly decrypting content to secure buffers. Testing: Ran App. Bug: 113594822 Change-Id: Icbb1e2f2e762bac3cc1b7b20749922c14ea24449
91 lines
3.3 KiB
Markdown
91 lines
3.3 KiB
Markdown
# Full Decrypt Path Testing Application
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Released August, 2019.
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This is the Full Decrypt Path Testing application. The application is used
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to test the full decrypt path of OEMCrypto.
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The app computes a hash of a clear frame, encrypts the frame, and sends both to
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OEMCrypto. OEMCrypto should decrypt, compute a hash, and then verify the
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hash. The app will display any errors in the hash.
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## Getting Started
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If OEMCrypto on the device supports CRC32 hash, then the application should work
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"out of the box". Install it using
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adb install FullDecryptPathTesting.apk
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To start a batch of tests, click on the "Start" button. The device needs to be
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connected to WiFi to fetch a license. Once the license is installed, it should
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cycle through a set of predefined tests and a bunch of random tests. The video
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surface should display a single frame, which is the FDPT logo.
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Press the "Clear" button to clear the logs if you want to run the tests again.
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## Settings
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To change which test to run, click on the "Setup" button. The default settings
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run two of the four standard modes, "cenc" and "cbcs" with 5000 randomly
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generated tests for each mode.
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## Running on a production device
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This application is intended to test decryption on a device running the full
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Android stack. However, most Level 1 OEMCrypto implementations will not support
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the decrypt hash feature on a production device. The feature will be optimized
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out on production devices. For this reason, it should not be suprising if no
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tests run when the settings for "Use Level 1" and "Use Secure Buffer" are set to
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true.
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## Running the application from adb
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The settings filed are stored on the device in the shared preferences
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directory. You can pull the XML file from the device, edit it, and push it back
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to the device:
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```shell
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DIR=/data/data/com.google.widevine.fulldecryptpathtesting/shared_prefs
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FILE=com.google.widevine.fulldecryptpathtesting_preferences.xml
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adb pull $DIR/$FILE
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```
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Now edit the xml file on your host computer. You can then push the file back
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to the directory. You might have to force-stop the application first, to force
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the preferences to be read again.
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```shell
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adb shell am force-stop com.google.widevine.fulldecryptpathtesting
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adb push $FILE $DIR/$FILE
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```
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Now that the settings have been updated, you can start the application from the
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command line:
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```shell
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adb shell am start -n "com.google.widevine.fulldecryptpathtesting/.MainActivity" \
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-d "start"
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```
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## Repeatable Tests
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If you want to re-run a test with the exact same test cases, you may change the random seed
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in the settings. Each run prints the random seed that it uses in the logcat.
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If you don't set the seed, the application picks a random seed using a secure
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random number generator.
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## Source Code
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The app builds with Android Studio.
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Vendors who wish to supply their own hashing function instead of using CRC32
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should edit the file HashGenerator.java or the C++ file native-lib.cpp.
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BUILD ERRORS:
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If you see the error below you might not have CMake installed.
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```shell
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>> * What went wrong:
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>> A problem occurred configuring project ':mobile'.
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>> > java.lang.NullPointerException (no error message)
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```
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Because the app includes native code written in C++, it requires CMake. From
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the tools menu, select Android and Android SDK Manager. On the tab "SDK Tools",
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make sure that Cmake is selected.
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