LAContext evaluatePolicy not showing TouchID prompt

Question

ziwei.zhao OP

Created Aug ’19

Replies 21

Boosts 0

Views 11k

Participants 11

We are using LAContext evaluatePolicy API to show the TouchID prompt in our App.

If we place our finger for authentication, then we can see the TouchID prompt and it completes the authentication.
What's even more strange is that when we can't see the pop-up window, then shake the device can make it appear.

😐

A simple project with code below:

 #import "ViewController.h"
#import 
@interface ViewController ()
@end
@implementation ViewController
- (void)viewDidLoad {
    [super viewDidLoad];
}
- (void)viewDidAppear:(BOOL)animated{
    dispatch_async(dispatch_get_main_queue(), ^{
        LAContext *context = [[LAContext alloc] init];
        [context evaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics localizedReason:@"xxxx" reply:^(BOOL success, NSError *error) {
            dispatch_async(dispatch_get_main_queue(), ^{
                NSLog(@"Verify successful");
            });
        }];
    });
}
@end

iPhone 6s

iOS 13-beta6

iOS 13-bata1 same behavior

iOS 13-beta5 same behavior

Boost

Answer 1

ziwei.zhao OP

Aug ’19

This stange issue disappear when i update to iOS13.0(17A5556d)

0

Answer 2

jfcs OP

Sep ’19

I am on iOS 13.1 public beta 3 (17A5837a) and am still seeing this issue. The problem is that it doesn't happen every time. It does still happen though.

0

Answer 3

lmDeveloper1 OP

Sep ’19

This is also happening to me on ios 13.1 beta 3, it seems to come and go and its completly random. I also noticed if you dont see the prompt just change orientation (in my case my ipad) and it will show up. It seems the view just sometimes doesnt show, I would file a bug report for it. Its weird i noticed it in ios 13 beta 1 then it went away completly , but now its back in ios13.1 beta 3. I also know its not just my app, other apps what use touch id, it randomly doesnt show also.

0

Answer 4

jfcs OP

Sep ’19

I submitted a bug report via their Feedback app. Probably wouldn't hurt if you all did as well.

It seems one workaround is to call evaluatePolicy twice. The second call will cancel and dismiss the first. If the first prompt happened to not show, the second seems to show everytime. If the prompt did show the first time, it will quickly display and then be dismissed and replaced with the second. I haven't found any other workarounds at this time.

0

Answer 5

lmDeveloper1 OP

Sep ’19

i also submitted a feedback.

0

Answer 6

lap0122 OP

Sep ’19

me too, do you have any solution?

0

Answer 7

chkpnt OP

Sep ’19

I can confirm this bug still exists in iOS 13.1 (17A844) and iOS 13.1.1 (17A854).

Calling SecItemCopyMatchig is affected by this bug, too.

A physical shake leads the Touch-ID-prompt to show up. Unfortunatly, a simulated shake event (I've written a FakeShaker, which provokes a UIMotionEvent) doesn't work.

0

Answer 8

tijme OP

Sep ’19

I've got the same issue on an iPhone 7 (iOS 13.1). It's not even the beta version. I'm using Valte (https://github.com/square/Valet) to manage TouchID unlock.

0

Answer 9

fysteven OP

Sep ’19

I see the same issue in iOS 13.1.1.

0

Answer 10

woodjobber OP

Sep ’19

I fix this bug.

LAContext *context = [[LAContext alloc]init];

NSError *error;

if ([fallbackTitle isKindOfClass:NSString.class]) {

context.localizedFallbackTitle = fallbackTitle;

}else {

context.localizedFallbackTitle = @"";

}

BOOL canEvaluate = [context canEvaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics error:&error];

if (canEvaluate) {

// It's working !!!

if (@available(iOS 13.0, *)) {

[context evaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics

localizedReason:[self biometricsText]

reply:^(BOOL success, NSError * _Nullable error)

{

}];

}

[context evaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics

localizedReason:[self biometricsText]

reply:^(BOOL success, NSError * _Nullable error)

{

//TODO:

}];

}

0

Answer 11

jfcs OP

Sep ’19

It appears that you are just simply calling it twice like I had mentioned. Or is this doing something else that I am not noticing?

https://forums.developer.apple.com/thread/121149#382237

The problem with this is that sometimes the prompt does display, and if that happens, then this code will display it again, causing the prompt to actually display twice.

0

Answer 12

jfcs OP

Sep ’19

Unfortunately, no. A not-so-great workaround is to call evaluatePolicy twice.

https://forums.developer.apple.com/thread/121149#382237

0

Answer 13

lmDeveloper1 OP

Sep ’19

It looks like its being reported now by iphone news outlets, maybe this will bring some awareness to it and apple will look into it.

https://9to5mac.com/2019/09/30/ios-13-iphone-touch-id-login-bug/

0

Answer 14

jfcs OP

Oct ’19

Thanks for sharing! Hopefully they get on this soon.

0

Answer 15

Nsdj1978 OP

Oct ’19

Seems to be fixed in 13.2 beta 1.

0

	#import "ViewController.h"
	#import
	@interface ViewController ()
	@end
	@implementation ViewController
	- (void)viewDidLoad {
	[super viewDidLoad];
	}
	- (void)viewDidAppear:(BOOL)animated{
	dispatch_async(dispatch_get_main_queue(), ^{
	LAContext *context = [[LAContext alloc] init];
	[context evaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics localizedReason:@"xxxx" reply:^(BOOL success, NSError *error) {
	dispatch_async(dispatch_get_main_queue(), ^{
	NSLog(@"Verify successful");
	});
	}];
	});
	}
	@end