QRemoteObjects not working when app is signed with system signature (Android)

delamor

I am using QRemoteObject to communicate between processes, it works fine so far when the app is signed with a random certificate; but as I need some permissions only granted to apps that has the system signature I signed the app with that signature and then QRemoteObject stops working.

The failure appears here:

m_repNode.connectToNode(QUrl(QStringLiteral("local:servicemessenger")));

m_repService = QSharedPointer<ServiceMessengerReplica>(
    m_repNode.acquire<ServiceMessengerReplica>());

bool res = m_repService->waitForSource();

res is null when system signature and true when random signature. I am not seeing anything relevant on logs.. anyone knows what is happening ?

I am seeing in logs SELinux blocking the creation of socket files, I think that's the cause but I am not sure on solution for this.

patrick521

Hello, @delamor

It seems SELinux is blocking your application from creating socket files when using the system signature. Follow these steps to resolve it:

Check SELinux Status and Logs:
getenforce
grep avc /var/log/audit/audit.log

Generate and Load Custom SELinux Policy:

grep avc /var/log/audit/audit.log | grep your_app_context > myapp-denials.log
audit2allow -M myapp-socket -i myapp-denials.log
semodule -i myapp-socket.pp

This will create and load a policy module that allows the necessary permissions for your app.

I hope this info is helpful to you.

Best Regard,
patrick521

@delamor said in QRemoteObjects not working when app is signed with system signature (Android):

I am using QRemoteObject to communicate between processes, it works fine so far when the app is signed with a random certificate; but as I need some permissions only granted to apps that has the system signature I signed the app with that signature and then QRemoteObject stops working.

The failure appears here:

m_repNode.connectToNode(QUrl(QStringLiteral("local:servicemessenger")));

m_repService = QSharedPointer<ServiceMessengerReplica>(
m_repNode.acquire<ServiceMessengerReplica>());

bool res = m_repService->waitForSource();
res is null when system signature and true when random signature. I am not seeing anything relevant on logs.. anyone knows what is happening ?

I am seeing in logs SELinux blocking the creation of socket files, I think that's the cause but I am not sure on solution for this.

osos11

@delamor
If you have the root access on your android device, try the following code. The code is used to change Selinux behavior "enforcing" to "permissive".

setenforce 0

After that your Qt app will work properly . Then you should check the SeLinux logs and share them with us.

Please write me the details of your Android device. Are you using custom AOSP build or stock firmware?

@patrick521
What you mentioned is not suitable for Android.