add HEK Service-App to attestation compatibility guide

[reifenrath-dev]

Recently I learned that the HEK service app from a German health insurance company also seems to use Play Integrity API and therefore cannot be used on GrapheneOS, so I would like to add it to the list.

[thestinger]

We need to confirm this somehow. Do you have a screenshot? Can you get logs from View logs in the Settings app? Might need from the OS in addition to the app but the app logs might be enough.

[reifenrath-dev]

@thestinger thanks for your response. I tried for some hours now to find some relevant parts in the app and system log. Unfortunately I'm not experienced in android development. I also tried to look at the logs of the Revolut App to get an idea of what to look for. I could not find anything saying "Play Integrity API" or similar (which I could also not find for the Revolut App, tough). However, the following lines could be relevant:

12-27 20:53:01.039  6607  6607 W libc    : Access denied finding property "ro.product.name_for_attestation"
12-27 20:53:01.039  6607  6607 W libc    : Access denied finding property "ro.product.device_for_attestation"
12-27 20:53:01.039  6607  6607 W libc    : Access denied finding property "ro.product.manufacturer_for_attestation"
...
12-27 20:53:01.038  6607  6607 W main    : type=1400 audit(0.0:16038): avc:  denied  { read } for  name="u:object_r:build_attestation_prop:s0" dev="tmpfs" ino=11280 scontext=u:r:untrusted_app:s0:c124,c256,c522,c768 tcontext=u:object_r:build_attestation_prop:s0 tclass=file permissive=0
12-27 20:53:01.039  6607  6607 W libc    : Access denied finding property "ro.product.brand_for_attestation"
12-27 20:53:01.039  6607  6607 W libc    : Access denied finding property "ro.product.model_for_attestation"
...
12-27 20:53:03.297  6607  6669 E GoogleApiManager: Failed to get service from broker. 
12-27 20:53:03.297  6607  6669 E GoogleApiManager: java.lang.SecurityException: Unknown calling package name 'com.google.android.gms'.
...
12-27 20:53:03.304  6607  6668 W CondFlagRegistrar: Failed to register com.google.android.gms.providerinstaller#com.google.android.gms
12-27 20:53:03.304  6607  6668 W CondFlagRegistrar: ehvp: 17: 17: API: Phenotype.API is not available on this device. Connection failed with: ConnectionResult{statusCode=DEVELOPER_ERROR, resolution=null, message=null}

Could you point me to what I have to look out for or if you have the time look at the full log?

The full HEK app log:
HEK log 53ae20b42e5e.txt