Cannot show 2 BiometricPrompts back-to-back with face unlock [157783075]

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Bug

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Description

ph...@monzo.com

created issue #1

May 30, 2020 11:07AM

If you show 2 BiometricPrompts back-to-back on a Pixel 4 (which uses face unlock), the second prompt will be immediately dismissed. This does not happen on devices that use fingerprint, like a Pixel 2.

I've attached a sample project that reproduces the issue. You can configure the delay between the first prompt being dismissed and the second being shown - with a delay of 400ms the issue reliably reproduces, and with a delay of 600ms it does not.

Here's a video of the sample on a Pixel 4: https://i.imgur.com/4sCWOm0.mp4

Here's a video of the sample on a Pixel 2: https://i.imgur.com/5dDI4zO.mp4

I believe it's caused by this postDelayed, which has a 500ms delay for face unlock and runs after the second prompt has been shown when 2 are shown back-to-back.

Note that this is a bug in the framework, not in the androidx.biometric library, but there doesn't seems to be a relevant component for framework biometrics (and it should be possible to work around this in androidx).

BUILD INFO:

Device type: Pixel 4
OS version: 10
Biometric library version: 1.0.1

STEPS TO REPRODUCE:

Install the sample.
Perform face unlock with the default 0 delay between prompts.

EXPECTED RESULTS: Both prompts work correctly.

OBSERVED RESULTS: The second prompt is immediately dismissed.

NUMBER OF TIMES YOU WERE ABLE TO REPRODUCE: 3/3

BiometricPrompt.zip

325 KB

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Comments

cu...@google.com <cu...@google.com> Aug 17, 2020 08:47PM

Reassigned to cu...@google.com.

ap...@google.com <ap...@google.com> #2Sep 3, 2020 06:34PM

Project: platform/frameworks/support
Branch: androidx-master-dev

commit f1c54b791ac77cc05436232486e2b1499d3a820c
Author: Curtis Belmonte <curtislb@google.com>
Date: Wed Sep 02 17:28:50 2020

Fix issue with showing BiometricPrompt back-to-back

Fixes an issue on some devices where using BiometricPrompt for
authentication again soon after it is dismissed causes the new prompt to
be dismissed as well. Because this solution involves adding artificial
latency to the second prompt invocation, it is currently limited to
known affected devices and Android OS versions.

Test: BiometricPrompt sample app from

b/157783075

on API 29-30.
Test: Biometric integration test app on API 27-30.
Test: ./gradlew biometric:biometric:test
Test: ./gradlew biometric:biometric:connectedAndroidTest
Test: ./gradlew biometric:integration-tests:testapp:connectedAndroidTest

Bug: 157783075
Change-Id: I830402327b759f5297721e992c4f3e617fc94d61

M biometric/biometric/src/androidTest/java/androidx/biometric/DeviceUtilsTest.java
M biometric/biometric/src/main/java/androidx/biometric/BiometricFragment.java
M biometric/biometric/src/main/java/androidx/biometric/BiometricViewModel.java
M biometric/biometric/src/main/java/androidx/biometric/DeviceUtils.java
M biometric/biometric/src/main/res/values/devices.xml

https://android-review.googlesource.com/1419278

cu...@google.com <cu...@google.com> #3Sep 3, 2020 09:29PM

Marked as fixed.

This issue should be fixed by commit f1c54b7 for any delay >= 1ms. The prompt can also be shown again immediately (with 0ms delay) by posting to the main thread via a Handler, rather than invoking inline in the onAuthenticationSucceeded callback.

It's worth noting that this solution is currently device-specific to avoid introducing unnecessary latency. Please reopen this issue or file a new one if the problem is found to persist on any devices not currently covered.

ap...@google.com <ap...@google.com> #4Sep 4, 2020 01:29AM

Project: platform/frameworks/support
Branch: androidx-master-dev

commit a44bc71d502aeb298c1b0a24c8c2373423bafcb9
Author: Curtis Belmonte <curtislb@google.com>
Date: Thu Sep 03 17:29:09 2020

Use exact model names for biometric prompt delay

The previous solution to delay showing the biometric prompt on some
devices incorrectly matched some unaffected devices based on model
prefix. This change addresses the problem by restricting the solution to
exact model string matches.

Test: BiometricPrompt sample app from

b/157783075

on API 29-30.
Test: Biometric integration test app on API 27-30.
Test: ./gradlew biometric:biometric:test
Test: ./gradlew biometric:biometric:connectedAndroidTest
Test: ./gradlew biometric:integration-tests:testapp:connectedAndroidTest

Bug: 157783075
Change-Id: Icdf953d9b34c296769f15f51007cdab5d43b5124

M biometric/biometric/src/androidTest/java/androidx/biometric/DeviceUtilsTest.java
M biometric/biometric/src/main/java/androidx/biometric/DeviceUtils.java
M biometric/biometric/src/main/res/values/devices.xml

https://android-review.googlesource.com/1419735

Issue 157783075

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Issue summary

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cu...@google.com <cu...@google.com> Aug 17, 2020 08:47PM

ap...@google.com <ap...@google.com> #2Sep 3, 2020 06:34PM

cu...@google.com <cu...@google.com> #3Sep 3, 2020 09:29PM

ap...@google.com <ap...@google.com> #4Sep 4, 2020 01:29AM

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