This is a simple Android application whose purpose is to display fullscreen non-interactive dashboards on Android devices. Its main use is to be run from an Android stick plug on some TV to run the web application to display dashboards.
Currently, the minimal version of Android is 4.1 (Jelly Bean. Dashkiosk is using the Crosswalk project to provide an up-to-date webview with support of recent technologies.
There are a lot of Android devices that you can choose to run Dashkiosk on. When choosing one, prefer the ones which can be upgraded to Android 4.2.
Many cheap devices are using a Rockchip SoC limited to a 720p resolution. This can be circumvented with some non official experimental firmwares but usually, this is a sufficient resolution to display dashboards.
The following devices  are known to work reasonably well:
- It registers as a possible home screen. It is therefore to run the application on boot.
- It provides a really fullscreen webview. Absolutely no space lost in bars.
- No possible interactions. If run on a tablet, the user is mostly locked out. However, there are still some way to interact with the device while the application is running by invoking the settings and changing the home application from here.
- Prevent the device going to sleep.
If you don’t want to compile the Android app yourself, you can download a pre-compiled version from GitHub.
Building from source is just a matter of following those two simple steps:
Clone the git repository.
Build the application with the following command:./gradlew assemble
At the end of the compilation, you get build/outputs/apk/dashkiosk-android-debug.apk that should be installed on the Android device.
You need the adb tool. On Debian and Ubuntu, you can install the android-tools-adb package to get it. Otherwise, it is available in the platform-tools of the Android SDK. If you didn’t install the SDK yourself, it should be in ~/.android-sdk. If adb is not present in the platform-tools directory, you can install it with:
tools/android update sdk --no-ui --all --filter platform-tool
You can then install the APK on a device attached through USB on your computer with the following command:
adb install -r build/outputs/apk/dashkiosk-android-debug.apk
Alternatively, you can just point a browser to the APK and you will get proposed to install it. You need to ensure that you allowed the installation of APK from unknown sources.
The next step is to run the configuration panel. This panel can be accessed by using the back button while the loading screen is running. It can be accessed later by clicking on the pen icon in the action bar.
The orientation is configured to landscape by default. You can choose either auto or portrait.
If you want to lock a bit the application, you can lock settings to prevent any further modifications. You can still revert the changes by invoking the preferences activity with adb:
adb shell am start -n \ com.deezer.android.dashkiosk/com.deezer.android.dashkiosk.DashboardPreferences
The important part is to input the receiver URL. You can check that this is the correct URL with any browser. You should see a dashboard with some nice images cycling.
The timeout is not really important. Until the application is able to make contact with the receiver, it will try to reload the receiver if the timeout is reached.
Alternatively, the configuration can be done at compile-time by modifying res/xml/preferences.xml.
Unfortunately, it is currently not possible to trust third-party certificates. Trusted certificates are built into the app and cannot be modified.
The only possibility is to accept untrusted certificates in the preferences. This makes TLS useless and you could just use HTTP, except if you are interested in client certificates. In this case, blindly trusting the server certificate doesn’t allow an attacker to use your client certificate for its own requests (client has to demonstrate its ability to sign a the whole handshake with its certificate, including the “server certificate” message).
It is possible to use client certificates. The support is still quite new and may be troublesome to implement. Be sure to use adb logcat -s DashKiosk AndroidRuntime while running to spot any error.
Creating a keystore¶
Currently, you can only provide one client certificate and it will be used with any site requesting a client certificate. The certificate needs to be provided as a BKS (BouncyCastle KeyStore). You can either use keytool or Portecle, a graphical tool to manage such a store. You can find a cheatsheet to use keytool. If you already have your client certificate as a PKCS#12 file, you only need to use keytool -importkeystore:
keytool -importkeystore \ -destkeystore clientstore.bks \ -deststoretype BKS \ -provider org.bouncycastle.jce.provider.BouncyCastleProvider \ -providerpath /usr/share/java/bcprov.jar \ -srckeystore client.p12 \ -srcstoretype PKCS12
You will be prompted the password to protect the newly created keystore and the password protecting the PKCS#12 file. Ensure you use the same password for both: keytool seems to protect the private key with the password from the PKCS#12 file while Dashkiosk will use the same password for the private key and for the keystore.
On Debian, bcprov.jar is from the libbcprov-java package. Be sure to only put one keypair in the store. Dashkiosk wil always use the first one.
If you have your certificates in PEM format, you can convert them in PKCS#12 with the following command:
openssl pkcs12 -export -out client.p12 \ -in cert.pem \ -inkey key.pem \ -certfile ca.pem
You can import several certificates in the keystore.
Providing the keystore to the application¶
There are two ways to provide a client certificate to the application. The first one is to put the certificate on the filesystem. For example, in /sdcard/dashkiosk.bks. Then, in the preferences, ensure to untick Embedded keystore and tick External keystore, then specify the path to the keystore in Keystore path. The second one is to embed the client certificate directly into the application. Replace the file res/raw/clientstore.bks by your own and recompile the application. In the preferences, ensure you tick Embedded keystore. In both cases, you also need to provide the password protecting the keystore.
Grant permissions to read the keystore¶
Starting from Android 6, you also have to grant Dashkiosk the permission to access the keystore if you use the external one. This can be done in Android Settings. Go to Applications, click on Dashkiosk. You should see a Permissions tab. The only item in this tab should be Storage. Enable it.
Once configured, just run the application as usual. You can also click on the home button and choose the application from here to make it starts on boot.
Still with adb, you can see the log generated by the application with the following command:
adb logcat -s DashKiosk AndroidRuntime
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