I've a signing and compiled APK but I can not install it on a rooted device.
I've tried:
- Put APK on system/priv-app folder
- Run adb set-device-owner
- Install apk using adb install
And nothing...
I want to enroll my device with COPE ownership.
Thanks in advance
Martín
In order to use system service, you might need to sign the system service with system signing key (i.e the key which used to sign the Android OS). In the system service manifest, it set as follows in order to work as a system application
android:sharedUserId="android.uid.system"
However if you need to run this on a rooted device, you can simply remove that attribute from the manifest and make app as a system app using root utility application in order to enroll device with COPE ownership.
Related
I have access to an Android tablets' platform key and certificate. I'm attempting to build an app and install it with system level privileges by doing the following:
Create a Java KeyStore file with platform.pk8 and platform.x509.pem using the bash script called platform_import_keystore found on GitHub.
In AndroidManifex.xml add the following:
<uses-permission android:name="android.permission.READ_LOGS"/>
android:sharedUserId="android.uid.system"
Sign APK with PLATFORM key and certificate using a Java KeyStore file in Android Studio.
Install APK
When the app runs, the system denies READ_LOGS permission.
Why isn't my app running with system level permissions?
What #Mark mentions is correct to some extent, for system apps.
I think you are doing something else wrong.
I have tried this with system apps as well, and as long it was signed with the platform keystore, it works. Now this was on Android 8 and Android 9. You haven't mentioned the AOSP version running the device.
That changes things AFAIK, so if it's AOSP 10+, it might behave differently.
Also the other comments are missing another key thing SELinux. SELinux is not permissive for user builds. Verity is enabled, and you cannot have root access. So you cannot push the app into /system/priv-app/ or push it into /vendor/app/.
You cannot access system resources without proper SE Policy files. You can check the logs yourself, to see avc denied messages.
I think overall what you are seeing should be inline with AOSP's security ideals. An app signed with System keys should not be able to get system permissions. It also needs to be located in the correct place, either as a privileged app or vendor app. Such apps need to be whitelisted. There's a built in script in AOSP source to even generate the permissions for whitelisting (it produces the required xml)
There's two classes of system apps, /system/app/ and /system/priv-app/
The privileged apps are the only ones that get signature level permissions, and according to newer versions of android, you need to enable whitelisting in the /system/etc/priv_app-permissions_device_name.
If you make any changes to the system or vendor when verity is enabled, firstly they are mounted read only, but somehow if you do make a change, the device will brick itself. This is the security feature. All custom development needs to be done in userdebug builds with SELinux in permissive mode, and then all the permissions need to be predefined, SE Policies fine tuned to utmost minimal, only then the user build can function normally. User build is not at all suitable for AOSP development activities, even if it's just for testing or trying out a single app.
User build is production type build that the end user can use and is not for development. It's the most secure form of android, so if you have platform keys, it may never be enough.
All that being said, I'm sure you don't have the right keys. Just pull an app from system/priv-app/ and use keytool or similar to check it's signature, and then try to match with your release apk.
It's little complicated as it is, and kind of hard to explain and there are levels of permissions also in android, so if you aren't following a specific approach/path, you will not be able to get it to work.
I have started to work on AOSP and I have a couple of applications that I do not to update when I update my OS. I tried using the vendor partition and flashing my specified appilcations on the vendor partition which built successfully. During run time the application crashed since it needs some system level permissions. Is there any way I can have a system app on the vendor partition ?
Have this in your manifest
android:sharedUserId="android.uid.system"
Then using Android Studio menu Build > Build APK(s). Then take that apk and sign with system signature using pek and pk8 files. Then push them in /vendor/app
OR Build the app using AOSP tree. Push that apk from out//vendor/app/ .
Hope this helps.
What I should to do to create a system app (to obtain rights to use android:sharedUserId="android.uid.system"in manifest file without receiving an error from package manager about certification problem?
I use rooted phone with stock firmware.
Ok, I think that I find sollution from great xda developers: http://forum.xda-developers.com/showthread.php?t=1776095 here is full description how to obtain access to apps signed by platform keys.
Do you apply with this approach?
PS it is interesting that users from stack instead of investigating hard problem immediately say that you can not solve it, then reduce novice user's reputation...
What I should to do to create a system app
There are two types of system apps:
Apps installed on the system partition, which can be accomplished by users with root privileges
Apps signed by the same signing key that signed the firmware
to obtain rights to use android:sharedUserId="android.uid.system"
That definitely would require your app to be signed by the same signing key that signed the firmware. That's true for any android:sharedUserId.
But some guys edit stock apps, prepare zip file which user can update system apps by recovery.
You are welcome to provide any evidence that what they do somehow involves android:sharedUserId="android.uid.system".
A system app must be signed with the platform key. This is done by developers deploying an android platform on their own device, or mobile carriers.
If that is your case, the easiest way is to add this to your Android.mk:
LOCAL_CERTIFICATE := platform
LOCAL_PRIVILEGED_MODULE := true
or this to your Android.bp:
certificate: "platform",
privileged: true,
If you add those lines without adding android:sharedUserId="android.uid.system" to your manifest, you will be a platform_app. A system app is more privileged than a platform app. That uses the platform key and runs as the system user.
If you are not the platform vendor, the platform vendor would need to sign your application using their platform key. Some vendors, including my company, will do this for 3rd parties demonstrating a valid reason for doing so.
Without the signature, your application can only be used on rooted devices.
I did not need to sign my app with the firmware signature! I have a rooted device. Therefore I can grant myself rights to write to certain directories using adb.
I moved my app to /system/priv-app instead of /system/app using those steps: Push my apk to /system/app
Now, I can access system permissions like android.permission.SHUTDOWN
There is two types of system apps.
Type 1: The App which is in the same signature of the Device ROM .
Type 2: The Signed app which is in system/priv-app ( Might differ based on adnroid version ) in your device storage location .
Visit this link -> http://www.archive.ricston.com/blog/explaining-behavior-android-application-system-apps-nonsystem-apps/
I exported an unsigned apk file that represents a test version of my Android application. I need to distribute this to quite a few users. Is there a simple method to distribute the apk file where it will install the app? I'm trying to avoid the test users from having to download something like Astro or the sdk. Any ideas? I tried putting it out on a global web server and the file downloads but doesn't install. Thanks for the help!
From the android documentation:
The Android system will not install or run an application that is not
signed appropriately. This applies wherever the Android system is run,
whether on an actual device or on the emulator. For this reason, you
must set up signing for your application before you can run it or
debug it on an emulator or device.
So even if your users have the "Allow installing non-market apps" checked, your application will still have to be signed with at least a test key before it can be installed on a physical device.
I just put my experimental apps on the Android market with a description that says "don't install this, it won't work for you" and then give an access key to my testers.
I am building an app that will be bundled on an android device as a system app. The manufacturer is a ways out on delivering the device to us, so in the meantime I'd like to grant my app system level permissions in the emulator so I can work on an auto update feature that will do silent installs of APKs without any interactions from the user. From what I've read, its my understanding that the only way to be able to do silent installs on android is if your app is signed with the same cert as the OS. So how can I simulate this in the emulator?
If you want a signatureOrSystem permission, you just need to be placed on the system image; you don't need to be signed with any special cert. You can do this as a one-off (until you exit the emulator) like this:
> adb root
> adb remount
> adb push /path/to/My.apk /system/app/My.apk
Once you have done that, you can use the normal process to install further updates on the data partition ("adb install -r /path/to/My.apk" which is what the developer tools do when you run from Eclipse). When installing this way, the app retains any signatureOrSystem permissions it had requested from the original version on the system image, but can not gain any new such permissions.
If you need pure signature permissions, you need to sign your app with the same cert as whatever is declaring those permissions (typically the core framework, but the media system is a separate cert etc). If you are requesting signature permissions you don't need to be installed on the system image, you can just install it as a normal app and it can still get the permissions because of the signing.
As far as I can tell, you need to:
download the Android source and build an emulator firmware image.
sign your application with the keys in the Android source tree at /build/target/product/security/.
add android:sharedUserId="android.uid.system" to your application's manifest.
run your application on an emulator using the image built in step 1.
The reason for having to build your own firmware image is so that you can get at the keys. Now, it might be possible that the keys for the standard emulator image are available somewhere, which will save you the long and exceedingly tedious process of building your own Android, but I'm afraid I have no idea where these might be.
Disclaimer: never tried this myself.