[DISCUSSION] Play Integrity API

[V0latyle]

Play Integrity API

What is Play Integrity?
Play Integrity has replaced SafetyNet for the most part, with a deadline of June 2024, when Google's SafetyNet servers will go offline. Apps that continue to exclusively depend on SafetyNet will no longer work once this happens. Most developers have already migrated to Play Integrity.

Is Play Integrity the same as Play Protect?
No. Play Integrity provides users with the ability to verify device compatibility and security, much like SafetyNet did. Play Protect is a part of the Play Store that ensures that your device is certified, and helps to protect against malware. In this context, "certified" refers to whether or not your device has passed Android compatibility testing. This is also used for part of the Play Integrity checks. More information here


My device passes SafetyNet but I can't use Google Pay/other apps.
Don't rely on SafetyNet as a good assessment of your device's compatibility and security. It is possible to pass SafetyNet, but fail Play Integrity.
Rooted Pixel 5 on stock firmware: USNF 2.3.1 shows SafetyNet Pass using YASNAC, but device fails Play Integrity DEVICE_INTEGRITY check.

How do I know if my device is passing Play Integrity checks?
To check Play Integrity status, you can use this app:

Play Integrity API Checker - Apps on Google Play

Get info about your Device Integrity through the Play Intergrity API

play.google.com

Github

If you're a nerd and you want to check key attestation, use this:

Key Attestation Demo - Apps on Google Play

Demo for Key Attestation feature of the Android system.

play.google.com

Github

What causes a device to fail Play Integrity checks?
It depends on your Android version and device state. If you're on an old version of Android prior to 8.0, even an unmodified device will only pass BASIC_INTEGRITY and DEVICE_INTEGRITY, because they are not capable of hardware backed attestation methods. Android 8.0+ devices that are not modified or unlocked should pass all 3; Android 8.0+ devices with unlocked bootloaders will fail all 3, because the unlocked bootloader state means hardware backed attestation is not possible.

What do I do if my device is failing all 3 checks?
You can use the Universal SafetyNet Fix Magisk module 2.4.0 or higher, which forces basic attestation similar to pre Android 8. If you're on rooted OEM firmware, this should be sufficient for most apps including Google Pay. Custom ROMs and Chinese OEMs may have to use fingerprint altering methods to pass. It is not possible to pass STRONG integrity on an unlocked bootloader...unless it's"broken", like an ASUS ROG. Fortunately, this isn't a big deal, as no app developers are known to require that verdict.

Now, details on what Play Integrity is and how it works...


SafetyNet has been discontinued in favor of the new Play Integrity, which uses stronger methods to verify the security of a device. This is why many rooted users have been unable to use security sensitive apps, such as banking and DRM.

The three elements in Play Integrity are:

• MEETS_DEVICE_INTEGRITY: Corresponds to SafetyNet ctsProfileMatch. The app is running on an Android device powered by Google Play services. The device passes system integrity checks and meets Android compatibility requirements. (Device profile matches that of a device that has passed Compatibility Test Suite) A device that fails this will appear as Uncertified in Play Store.
• MEETS_BASIC_INTEGRITY: Corresponds to SafetyNet basicIntegrity. The app is running on a device that passes basic system integrity checks. The device may not meet Android compatibility requirements and may not be approved to run Google Play services. For example, the device may be running an unrecognized version of Android, may have an unlocked bootloader, or may not have been certified by the manufacturer. Most devices should pass this, even if they're rooted.
• MEETS_STRONG_INTEGRITY: Corresponds to SafetyNet HARDWARE_BACKED evaluationType. The app is running on an Android device powered by Google Play services and has a strong guarantee of system integrity such as a hardware-backed proof of boot integrity. The device passes system integrity checks and meets Android compatibility requirements. An unlocked bootloader will ALWAYS fail this label because boot integrity cannot be verified, meaning that hardware backed attestation methods cannot be used.

This table shows the relationship between SafetyNet and Play Integrity responses:

The most fundamental change is this: Play Integrity, by default, uses hardware methods to verify BASIC and DEVICE integrity, but also uses the same hardware methods as proof of boot and system integrity. What this means is that Play Integrity uses stronger (and unbreakable!) methods as "proof" of the BASIC and DEVICE verdicts, and uses the availability of these hardware backed methods to determine the STRONG_INTEGRITY verdict.

These hardware methods include hardware-backed key attestation as well as Verified Boot to verify that a device has not been tampered with. It is not possible to pass STRONG integrity on an unlocked and/or modified device, or a pre Android 8 device. (Notable exception being devices with broken keystores such as ASUS ROG)

It is worth noting that SafetyNet always provided the means for developers to force hardware backed evaluation types; none did, including Google. The same seems to still be true; most app developers require DEVICE verdict, "secure" apps require BASIC and DEVICE, but none are known to require STRONG.

So if Play Integrity defaults to unbreakable hardware backed attestation, what can we do if this is broken or unavailable on our devices?
Fortunately, we have the ability to force a basic attestation method that prevents the use of hardware checks, meaning it is possible to partially pass. Universal SafetyNet Fix 2.4.0 does this:
(Response from Play Integrity Checker on my rooted Pixel 5 with Universal SafetyNet Fix MOD by Displax)

You can find that module here:

Releases · kdrag0n/safetynet-fix

Google SafetyNet attestation workarounds for Magisk - kdrag0n/safetynet-fix

github.com

As far as how this is going to affect us in the future, it's up to the app developers to decide what results they want. In most cases, all they care about is BASIC and DEVICE. But if they really want to ensure that they're running on a trusted platform, they can require STRONG attestation, which cannot be spoofed or bypassed. BASIC and DEVICE can, because they use the same mechanisms that SafetyNet did. The million dollar question is whether they ever will.


For those interested in the timeline:

For more information, please read the discussion in this thread.

 

[pndwal]

But new devices have originally been released with A11 (or A12).
Hence, it's not possible to spoof A10 on those devices just by 'downgrading' the Android version

Then we come to the 'suggestions' to spoof fingerprints from a 'close device' (where A10 or earlier stock ROM was available) - but that just opens a Pandora box with who knows what kind of problems, because the same fingerprints are also used by system apps and services to drive various components:
- go to MHPC thread and find people who experimented with the same and lost fingerprint or the whole touch
- on another phone it could be camera or who knows what
- not to mention that spoofed CTS fingerprints may screw OTA and therefore brick the system

Yup... But this is what the @Displax mod solution is doing however, but targeting GMS... Also his USNF PR...

Also interesting:

This kills two rabbits:
• fix old SN CTS profile check on some weird Custom ROMs
• bypass Integrity (MEETS_DEVICE_INTEGRITY) for now.

https://github.com/kdrag0n/safetynet-fix/pull/207#issue-1317290126

@kdragon is taking interest... He's concerned about fingerprint mismatch issues too:

Have you noticed any features acting up with the old fingerprint?

Ideally, I think this should be scoped to Play Integrity code by identifying methods it calls near the beginning and end of integrity checks, and adding hooks to set and restore the fingerprint. I feel like setting a fingerprint that doesn't match the system in so many ways is bound to cause an issue somewhere.

So @Displax says it's "for now" / and is "just quick example (and core resolve) with temp fix for impatient people))... But need more testing with various devices." He agreed:

We need separate target hook for this (if feasible) - will be more polite solution...

Target process (one of?) "com.android.vending/com.google.android.finsky.integrityservice.IntegrityService"

https://github.com/kdrag0n/safetynet-fix/pull/207#issuecomment-1195951660

PW

 

[zgfg]

Yup... But this is what the @Displax mod solution is doing however, but targeting GMS...

Yeah, that's the point - he uses Zygisk to limit CTS prints only to GMS - therefore if you use getprop you won't see the CTS prints being changed (like if you would use MHCP for changing the prints)

See that USNF is Zygisk type module, MHCP is not - hence MHCP cannot filter the props changes only to particular app/process

Therefore, other apps (like camera, Samsung store, etc) are not troubled - they still see the proper props values

 

[pndwal]

Some Insight on the New Cat and Mouse Game...

Since many are asking:

Is there a fix for this? ... Can't pass MEETS_STRONG_INTEGRITY.

I'm posting this WOT.

I predict some will like it, some won't... You've been warned!

FWIW, Play Integrity MEETS_STRONG_INTEGRITY is akin to SafetyNet Evaluation type HARDWARE with CTS Profile match...

Banks could have used this before (w/ S/N API) but haven't as it would have excluded too many users/devices/customers... Nothing has actually changed with new PI API; MEETS_STRONG_INTEGRITY will exclude the same group, so it's doubtful they'll rush to require this verdict...

Basically, the means to enforce Hardware key-backed Attestation has already been here w/ either of these attestations, but banks don't want to exclude all those w/Android 7 and below, or many w/ broken keymaster 3+ implementations in Android 8+ devices (CTS Profile match with HARDWARE Evaluation type / MEETS_STRONG_INTEGRITY won't pass with locked bootloader), eg most OnePlus devices (nb. Keymaster may have been fixed in OnePlus devices launched with Android 12+)...

I'm guessing the banks may well leverage this at some point if the time arrives when they feel there is a sufficient critical mass of devices w/ working hardware-backed keymaster (ie w/ hardware keystore, A8+) to trade against the number of modded (bootloader unlocked) devices in use especially if they deem Google slow to close the fallback-to-basic-attestation loophole that has allowed modders to bypass hardware based attestation to CTS Profile match enforcement (by triggering fallback to BASIC Evaluation type as well as bypassing enforcement) and also to allow its counterpart, MEETS_DEVICE_INTEGRITY verdict. (Nb. This verdict should not properly be obtained on modded devices, and it requires the same attestations as S/N as well as the same tricks to trigger fallback to BASIC attestation and bypass enforcement) The incentive to use this foolproof means is also certainly being weighed constantly against the cost / need to use their own custom means of sophisticated 'root' detection...

Google also, as other authorities have commented, appears to be waiting for some 'acceptable' percentile / critical mass of such devices in use to be reached also, before they swing the 'big hammer' that is Hardware-backed Key Attestation enforcement and that will definitely spell the endgame for modders' use of bank apps, and possibly for OnePlus users and others whose devices have broken keymaster*

*Nb. There are exceptions, eg Asus ROG Phone 3, where broken keymaster actually results in PI MEETS_STRONG_INTEGRITY and S/N CTS Profile match with Evaluation type HARDWARE regardless of bootloader status instead of the converse...

It seems likely to me that OnePlus and other devices with broken keymaster can be spared if Google do prevent on-device triggering of fallbacks to basic attestation use simply by using device info contained in the cryptographic attestation sent to Google servers instead of userspace model props etc now used, to bypass enforcement at the server end. If they do this it would be a concession as modded OnePlus etc may then still be able to pass CTS Profile match / DEVICE_INTEGRITY while other modern modded devices won't...

This would, however, be a way to swing the hammer a bit sooner, and either way, as can be seen from the above, they may be forced to do this once banks do indicate a willingness to enforce
MEETS_STRONG_INTEGRITY in order to stop a landslide that would prevent all stock locked Android 7 and lower devices using bank apps etc... Or maybe they'll just let the landslide go and force bank app users to upgrade devices...

Hopefully this gives some insight regarding what pressures may finally force Google to properly deploy (ie. strictly enforce) Hardware-based Key Attestation on devices that support it...

Personally, I think Google has exercised great restraint, possibly out of some regard for the modding community since I can't see any other compelling reason not to have properly enforced CTS Profile match with HARDWARE Evaluation type where supported or Hardware attested MEETS_DEVICE_INTEGRITY sooner, unless the matter of ensuring that the API properly sees hardware identifiers (ie. these cannot be spoofed, which I believe would again require cryptographic server-side attestation that the device doesn't indicate the presence of hardware keystore) for bypassing hardware attestation enforcement in devices launched with Android 7 and earlier is proving difficult (but I'm fairly sure this mechanism will be a simple matter for Google and probably already in place)...

It may well be that Google is benevolently holding off but is using/will use MEETS_STRONG_INTEGRITY uptake data as tha natural indicator of the banks propensity for reliable HKA... My bet is that if Google doesn't have immediate plans to move to srtict HKA enforcement for MEETS_DEVICE_INTEGRITY, then they will when the banks themselves move to use the even stricter MEETS_STRONG_INTEGRITY verdict...

 

[V0latyle]

Since many are asking:

I've posted some information about Play Integrity MEETS_STRONG_INTEGRITY being akin to SafetyNet Evaluation type HARDWARE with CTS Profile match, but since it became a WOT, I put it here:
https://forum.xda-developers.com/t/magisk-general-support-discussion.3432382/post-87274009

PW

I've been meaning to ask....Since Google is replacing SafetyNet with Play Integrity, is it safe to assume that there will come a day when app developers (particularly Google) remove SafetyNet support from their apps, at which point those of us with root will be unable to force "legacy" attestation as with the modified USNF? Of course this will mean that all versions of Android prior to the implementation of HA/TEE will be excluded as well, but it's not uncommon for developers to stop supporting older platforms.

 

[V0latyle]

Some Insight on the New Cat and Mouse Game...

Since many are asking:

I'm posting this WOT.

I predict some will like it, some won't... You've been warned!

FWIW, Play Integrity MEETS_STRONG_INTEGRITY is akin to SafetyNet Evaluation type HARDWARE with CTS Profile match...

Banks could have used this before (w/ S/N API) but haven't as it would have excluded too many users/devices/customers... Nothing has actually changed with new PI API; MEETS_STRONG_INTEGRITY will exclude the same group, so it's doubtful they'll rush to require this verdict...

Basically, the means to enforce Hardware key-backed Attestation has already been here w/ either of these attestations, but banks don't want to exclude all those w/Android 7 and below, or many w/ broken keymaster 3+ implementations in Android 8+ devices (CTS Profile match with HARDWARE Evaluation type / MEETS_STRONG_INTEGRITY won't pass with locked bootloader), eg most OnePlus devices (nb. Keymaster may have been fixed in OnePlus devices launched with Android 12+)...

I'm guessing the banks may well leverage this at some point if the time arrives when they feel there is a sufficient critical mass of devices w/ working hardware-backed keymaster (ie w/ hardware keystore, A8+) to trade against the number of modded (bootloader unlocked) devices in use especially if they deem Google slow to close the fallback-to-basic-attestation loophole that has allowed modders to bypass hardware based attestation to CTS Profile match enforcement (by triggering fallback to BASIC Evaluation type as well as bypassing enforcement) and also to allow its counterpart, MEETS_DEVICE_INTEGRITY verdict. (Nb. This verdict should not properly be obtained on modded devices, and it requires the same attestations as S/N as well as the same tricks to trigger fallback to BASIC attestation and bypass enforcement) The incentive to use this foolproof means is also certainly being weighed constantly against the cost / need to use their own custom means of sophisticated 'root' detection...

Google also, as other authorities have commented, appears to be waiting for some 'acceptable' percentile / critical mass of such devices in use to be reached also, before they swing the 'big hammer' that is Hardware-backed Key Attestation enforcement and that will definitely spell the endgame for modders' use of bank apps, and possibly for OnePlus users and others whose devices have broken keymaster*

*Nb. There are exceptions, eg Asus ROG Phone 3, where broken keymaster actually results in PI MEETS_STRONG_INTEGRITY and S/N CTS Profile match with Evaluation type HARDWARE regardless of bootloader status instead of the converse...

It seems likely to me that OnePlus and other devices with broken keymaster can be spared if Google do prevent on-device triggering of fallbacks to basic attestation use simply by using device info contained in the cryptographic attestation sent to Google servers instead of userspace model props etc now used, to bypass enforcement at the server end. If they do this it would be a concession as modded OnePlus etc may then still be able to pass CTS Profile match / DEVICE_INTEGRITY while other modern modded devices won't...

This would, however, be a way to swing the hammer a bit sooner, and either way, as can be seen from the above, they may be forced to do this once banks do indicate a willingness to enforce
MEETS_STRONG_INTEGRITY in order to stop a landslide that would prevent all stock locked Android 7 and lower devices using bank apps etc... Or maybe they'll just let the landslide go and force bank app users to upgrade devices...

Hopefully this gives some insight regarding what pressures may finally force Google to properly deploy (ie. strictly enforce) Hardware-based Key Attestation on devices that support it...

Personally, I think Google has exercised great restraint, possibly out of some regard for the modding community since I can't see any other compelling reason not to have properly enforced CTS Profile match with HARDWARE Evaluation type where supported or Hardware attested MEETS_DEVICE_INTEGRITY sooner, unless the matter of ensuring that the API properly sees hardware identifiers (ie. these cannot be spoofed, which I believe would again require cryptographic server-side attestation that the device doesn't indicate the presence of hardware keystore) for bypassing hardware attestation enforcement in devices launched with Android 7 and earlier is proving difficult (but I'm fairly sure this mechanism will be a simple matter for Google and probably already in place)...

It may well be that Google is benevolently holding off but is using/will use MEETS_STRONG_INTEGRITY uptake data as tha natural indicator of the banks propensity for reliable HKA... My bet is that if Google doesn't have immediate plans to move to srtict HKA enforcement for MEETS_DEVICE_INTEGRITY, then they will when the banks themselves move to use the even stricter MEETS_STRONG_INTEGRITY verdict...

Would you consider possibly boiling this down to a fairly simpler explanation that we can sticky? It's likely this will be the topic of quite repetitive questions going forward.

I tried to explain it somewhat simply here, please let me know how far I missed the mark

 

[pndwal]

I've been meaning to ask....Since Google is replacing SafetyNet with Play Integrity, is it safe to assume that there will come a day when app developers (particularly Google) remove SafetyNet support from their apps,

I put info about this originally here:
https://forum.xda-developers.com/t/magisk-module-universal-safetynet-fix-2-3-1.4217823/post-87188299

Google is urging Devs to do just that; S/N API was already depreciated in June with 'full turndown' slated for June 2024... banks are urged to move to PI asap, and at least before the June 2023 migration deadline. If they do, their older versions will continue to function with S/N API till June 2024. If they don't, these will cease to gat needed attestations from June 2023.

at which point those of us with root will be unable to force "legacy" attestation as with the modified USNF?

No, the new API includes all of the same device state checks and app processees use either one or the other, (although GPay seemed to use one for the app info and the other for card setup... but I'm betting it's only due to progressive changes...) so S/N turnoff won't matter...

You'll notice that if CTS Profile match fails for example, Device Integrity will fail also... The new API is a little stricter, especially for A11+ devices but @Displax's new USNF covers new enforcement bypass needed for these devices... The old bypasses are also still needed... And an official Pull Request is pending. (My Android 10 device doesn't need any change from official USNF)

Of course this will mean that all versions of Android prior to the implementation of HA/TEE will be excluded as well, but it's not uncommon for developers to stop supporting older platforms.

This is the point of what I just posted; if Google swings the enforce HKA if supported for MEETS_DEVICE_INTEGRITY hammer first, banks likely won't move to MEETS_STRONG_INTEGRITY sparing pre A8 stock devices... If they don't, eventually banks will implement MEETS_STRONG_INTEGRITY which will exclude customers using pre A8 devices... Either way it's game over for modders at that point... At least that's what my deduction says!

See official dates, info, links from here:
https://developer.android.com/training/safetynet/deprecation-timeline

PW

 

[zgfg]

I've been meaning to ask....Since Google is replacing SafetyNet with Play Integrity, is it safe to assume that there will come a day when app developers (particularly Google) remove SafetyNet support from their apps, at which point those of us with root will be unable to force "legacy" attestation as with the modified USNF? Of course this will mean that all versions of Android prior to the implementation of HA/TEE will be excluded as well, but it's not uncommon for developers to stop supporting older platforms.

That's something we can only speculate about.
Frankly, Google did not need Play Integrity - they could have simply forced CTS Profile checking through TEE (same thing as STRONG now) - but they didn't (yet)

Per specification, Google is not the final Judge. It only provides info how your device passes the Play Integrity API levels

If you are developer of a banking app, it is up to you would you allow DEVICE integrity, or would you require STRONG. Not even your banking app but better the banking server should make the final judgement (upon being passed the PI API test results)

Again, frankly, bankers could have already been checking do you pass CTS Profile with HARDWARE_BACKED or only BASIC, and allow only the first ones (they can also read that info with the old SafetyNet)

Btw, bankers (developers) can employ a more complex logic. Based on your phone model to require STRONG (new phones) or allow DEVICE (for older phones) - but it requires more work on their side

 

[pndwal]

Wow.. another thread ... Perhaps we could condense this in @Didgeridoohan's GPay thread?

Anyway, since you asked me to critique:

The reason for this is that Google is sunsetting the SafetyNet and Play Protect certifications

I hadn't heard about Play Protect depreciation (it's still there currently, and Play Store is already using Play Integrity API!), but SafetyNet is already deprecated...

in favor of the new Play Integrity API, which uses 3 fields:

MEETS_DEVICE_INTEGRITY

• The app is running on an Android device powered by Google Play services. The device passes system integrity checks and meets Android compatibility requirements. This is replacing SafetyNet's ctsProfile. This is what USNF fixes.

MEETS_BASIC_INTEGRITY

• The app is running on a device that passes basic system integrity checks. The device may not meet Android compatibility requirements and may not be approved to run Google Play services. For example, the device may be running an unrecognized version of Android, may have an unlocked bootloader, or may not have been certified by the manufacturer. This is replacing SafetyNet's basicIntegrity, and means that Play Services has not detected root.

MEETS_STRONG_INTEGRITY

• The app is running on an Android device powered by Google Play services and has a strong guarantee of system integrity such as a hardware-backed proof of boot integrity. The device passes system integrity checks and meets Android compatibility requirements.
  This is replacing SafetyNet's Hardware Attestation, and uses the Android system's Trusted Execution Environment to guarantee process security. This will not pass with an unlocked bootloader, and cannot be spoofed as it specifically relies on hardware security; unlocking the bootloader "breaks" TEE.

The workaround for this is the modded USNF module by @Displax which forces the system to use the old SafetyNet API instead of Play Integrity.

Um, no...

It simply allows PI MEETS_DEVICE_INTEGRITY verdict in Android 11+ (generally), by creating a fingerprint prop SDK-level (and possibly other) mismatch that triggers bypassing of Hardware keystore attestation enforcement... The original USNF fallback trigger (fake keystone registration) and enforcement bypass (altered Model prop) are also needed for MEETS_DEVICE_INTEGRITY verdict, and these alone are enough for many devices (pre-Android 11 generally).

I imagine at some point in the future when SafetyNet is completely retired, app developers (especially large ones like Google) will eventually remove support for SafetyNet in their apps, which will mean that anyone whose device does not pass Play Integrity will not be able to use the app. This will include everyone running versions of Android older than 8.0, when TEE was implemented.

Hardware keystore and hardware TEE have been around at least since Android 6, but keymaster could not reliably verify the key pairs were in hardware... This was strengthened in Android 7 Keymaster 2 attesting to hardware backed keys, but only Android 8's Keymaster 3, with ID attestation allowing the device to provide proof of hardware identifiers, such as serial number or IMEI, was considered an attestation strong enough for HKA in android..

The other points are treated in my post above. PW

 

[zgfg]

Would you consider possibly boiling this down to a fairly simpler explanation that we can sticky? It's likely this will be the topic of quite repetitive questions going forward.

I tried to explain it somewhat simply here, please let me know how far I missed the mark

You may also see this answer (we are all talking the same things, maybe with slightly different words):
https://forum.xda-developers.com/t/...agisk-discussion-thread.3906703/post-87274309

 

[V0latyle]

I admit it's a little hard to wrap my brain around this.

My understanding of the Play Integrity API was originally that in order to meet Play Integrity as a whole, devices would have to meet the BASIC, DEVICE, and STRONG integrity. I didn't know the apps looked at those qualities directly - I thought Play Integrity checked these, and if any of them was false, Play Integrity would report that integrity is compromised.

I promise I'm not being obtuse...

So the way it REALLY works is that the API is a method by which the apps can check these properties; it doesn't rely on a Google specific process (because AOSP)
Which means I still don't quite understand...how does the modded USNF allow apps such as GPay and Wallet to ignore the MEETS_STRONG_INTEGRITY?

It's clear to me that almost any device should return MEETS_BASIC_INTEGRITY, and that we have to use workarounds such as USNF to be able to return MEETS_DEVICE_INTEGRITY, and that we will never be able to return MEETS_STRONG_INTEGRITY because of HKA vs unlocked bootloaders.

 

[zgfg]

I admit it's a little hard to wrap my brain around this.

My understanding of the Play Integrity API was originally that in order to meet Play Integrity as a whole, devices would have to meet the BASIC, DEVICE, and STRONG integrity. I didn't know the apps looked at those qualities directly - I thought Play Integrity checked these, and if any of them was false, Play Integrity would report that integrity is compromised.

I promise I'm not being obtuse...

So the way it REALLY works is that the API is a method by which the apps can check these properties; it doesn't rely on a Google specific process (because AOSP)
Which means I still don't quite understand...how does the modded USNF allow apps such as GPay and Wallet to ignore the MEETS_STRONG_INTEGRITY?

It's clear to me that almost any device should return MEETS_BASIC_INTEGRITY, and that we have to use workarounds such as USNF to be able to return MEETS_DEVICE_INTEGRITY, and that we will never be able to return MEETS_STRONG_INTEGRITY because of HKA vs unlocked bootloaders.

Here (again) link to Google's doc:

Overview of the Play Integrity API | Google Play | Android Developers

developer.android.com

Pay attention to verdict - but better spend 15 minutes to read the whole

And in YASNAC, you can also read the JSON with eg details was the CTS Profile checked on TEE or not (= STRONG integrity for the be PI API)

 

[pndwal]

Frankly, Google did not need Play Integrity - they could have simply forced CTS Profile checking through TEE (same thing as STRONG now) - but they didn't (yet)...

FWIW, the real reason for the change was to provide an inclusive Integrity solution that

helps protect your apps and games from potentially risky and fraudulent interactions, allowing you to respond with appropriate actions to reduce attacks and abuse such as fraud, cheating, and unauthorized access.

by combining existing SafetyNet attestation in Device Integrity fields with the new Application integrity and Account details fields in a single API.

PW

 

[pndwal]

I admit it's a little hard to wrap my brain around this.

My understanding of the Play Integrity API was originally that in order to meet Play Integrity as a whole, devices would have to meet the BASIC, DEVICE, and STRONG integrity. I didn't know the apps looked at those qualities directly - I thought Play Integrity checked these, and if any of them was false, Play Integrity would report that integrity is compromised.

I promise I'm not being obtuse...

So the way it REALLY works is that the API is a method by which the apps can check these properties; it doesn't rely on a Google specific process (because AOSP)
Which means I still don't quite understand...how does the modded USNF allow apps such as GPay and Wallet to ignore the MEETS_STRONG_INTEGRITY?

It's clear to me that almost any device should return MEETS_BASIC_INTEGRITY, and that we have to use workarounds such as USNF to be able to return MEETS_DEVICE_INTEGRITY, and that we will never be able to return MEETS_STRONG_INTEGRITY because of HKA vs unlocked bootloaders.

Apps can use MEETS_DEVICE_INTEGRITY by default, using any distribution channel. Registration with Google Play allows use of MEETS_BASIC_INTEGRITY and MEETS_STRONG_INTEGRITY in addition...

Flow chart:

PW

 

[V0latyle]

Here (again) link to Google's doc:

Overview of the Play Integrity API | Google Play | Android Developers

developer.android.com

Pay attention to verdict - but better spend 15 minutes to read the whole

And in YASNAC, you can also read the JSON with eg details was the CTS Profile checked on TEE or not (= STRONG integrity for the be PI API)

I have read this and keep going back but I'm no developer and my general understanding of Android is less than elementary

Apps can use MEETS_DEVICE_INTEGRITY by default, using any distribution channel. Registration with Google Play allows use of MEETS_BASIC_INTEGRITY and MEETS_STRONG_INTEGRITY in addition...

This is where it's still confusing to me. Because according to that statement, it sounds like developers can choose what guarantee of security they want...but

Flow chart:

PW

This makes it sound like Play Integrity is not so much a framework as it is a service, meaning at some point app developers will have no choice?

Or am I right on both accounts, but app developers can either call the Play Integrity API, or they can call the device security fields alone?

 

[V0latyle]

@ipdev @pndwal @zgfg @TraderJack I know it's a lot of work, but could you please move your posts on Play Integrity into this thread as described above? The idea is to have one thread to discuss this topic, as well as a place to point other users to should they have questions. If someone would like to volunteer their post, I can copy/paste into the OP so we have an up front explanation of what Play Integrity is, how it works, and what it means for rooted/modded users.

 

[zgfg]

@ipdev @pndwal @zgfg @TraderJack I know it's a lot of work, but could you please move your posts on Play Integrity into this thread as described above? The idea is to have one thread to discuss this topic, as well as a place to point other users to should they have questions. If someone would like to volunteer their post, I can copy/paste into the OP so we have an up front explanation of what Play Integrity is, how it works, and what it means for rooted/modded users.

Is it possible to move the posts without copy-pasting them?

I mean it is if I mark it is Report and ask you to move - but then it's more work for you. Hence some other way?

 

[V0latyle]

Is it possible to move the posts without copy-pasting them?

I mean it is if I mark it is Report and ask you to move - but then it's more work for you. Hence some other way?

No, only moderators can move posts (and we have forum specific moderators so it wouldn't be me lol)

Else, you can copy/paste and request the old post be deleted

 

[pndwal]

I have read this and keep going back but I'm no developer and my general understanding of Android is less than elementary

X2

This is where it's still confusing to me. Because according to that statement, it sounds like developers can choose what guarantee of security they want...

Well Hardware evaluationTypes are used if available by default even if just calling Device_Integrity. That's why @kdragon uses both fake keystone (causes exception which triggers fall back to basic attestation) and altered Model prop (mismatch causes enforcement of a Hardware based verdict to be bypassed, ie. the forced basic attestation becomes acceptable)...

The statement "JSON ... details was the CTS Profile checked on TEE or not (= STRONG integrity for the be PI API)" may be misleading; really, MEETS_STRONG_INTEGRITY only indicates a passing STRONG_INTEGRITY verdict using hardware TEE; of course, unlocked devices will fail to return MEETS_STRONG_INTEGRITY and there will be no indication whether hardware TEE was used or not in PI, unlike old S/N attestation... Conversely, CTS Profile will be checked in TEE (ie. we see S/N HARDWARE evaluationType) to attest to DEVICE_INTEGRITY if it's available by default (ie. on A8+ devices), but if it fails there is no indication from PI API that hardware TEE was used, and no indication if hardware was used if it succeeds either unless STRONG_INTEGRITY succeeds also...

Don't confuse evaluationType with the choice of verdict type; Devs can choose any of three levels for verdict but cannot choose evaluationType used; Hardware will be used if it's available for that type unless userspace tricks are used to spoof device and cause fallbacks...

but

This makes it sound like Play Integrity is not so much a framework as it is a service, meaning at some point app developers will have no choice?

It's an API, (Application Programming Interface) requiring server-end support by Google; I gave you the dates / link a couple of times now for 'Migration deadline' & 'Full turndown' of S/N API at which point there will be no choice but to use PI API...

Or am I right on both accounts, but app developers can either call the Play Integrity API, or they can call the device security fields alone?

Sorry, are you referring to Play Integrity response labels?... These are all part of Play Integrity, of course!?

Main signals (responses) are defined as:

- Application integrity
- Account details
- Device integrity

For Device integrity, device_recognition_verdict is called.

By default, this can have one of the following labels:

MEETS_DEVICE_INTEGRITY
or
No labels (a blank value)

If you opt in to receive additional labels in Device integrity, device_recognition_verdict can have the following additional labels:

MEETS_BASIC_INTEGRITY
or
MEETS_STRONG_INTEGRITY
and for emulators only
MEETS_VIRTUAL_INTEGRITY

These 'fields' are all called via the Device Integrity API.

https://developer.android.com/google/play/integrity/verdict

PW

PS. Just did this on 140 min flight from Broken Hill to Sydney... Just landed...

 

[ipdev]

I am not sure about the Google Pay Magisk Discussion Thread but, posts (including mine) related to Play Integrity in the Universal SafetyNet Fix 2.3.1 thread seem to start around Post # 1,796.

All the posts about Play Integrity (that are not related to the USNF module) would have to be moved and kept in order to this thread.
I am not sure how easy that would be to do, since a lot of the discussion included linked posts in the responses.

Maybe @mrjuniork has an idea of the best and easiest way to do it?

Cheers.

PS.
Sorry to ping you mrjuniork.
I might be wrong but, it looks like you will be the one who gets stuck moving the posts.