I’m migrating a .NET MAUI iOS authorization flow from one that handles redirect using the now-deprecated custom URL scheme to one that employs an Universal App Link verified via a apple-app-site-association file hosted on Firebase.
The callback works. The code is received successfully. The issue is that the app crashes upon returning from the WebAuthenticator authorization flow. This is a problem with iOS only, not Android which works perfectly using an Android App Link served by a assetlinks.json file on the same server.
Short question
Have you gotten this to work? In that case skip all the laborious details and walk me through it! Otherwise, here is…
What I’ve tried
- Verify the Universal App Link using the Developer settings on iPhone.
- With the app debugger attached, inject the URL in Safari from a special “redirect test” page on our server. Verify that a breakpoint in
ContinueUserActivityis hit. Verify that the app does not crash when the Universal App Link is exercised in this manner.
- Setting a breakpoint to inspect the returned authorization code. Then returning immediately to avoid any possibility of other exceptions.
buttonLogin.Clicked += async (sender, e) =>
{
var clientId = "123456789012-1ok9rauo969og7aljrnri1gesrr7l1b3.apps.googleusercontent.com";
var redirectUrl = "https://myfirebasedomain.com/auth";
var scopes = "profile%20openid%20email";
var authUrl = $"https://accounts.google.com/o/oauth2/auth?client_id={clientId}&redirect_uri={redirectUrl}&prompt=consent&response_type=code&scope={scopes}&access_type=offline";
Uri authUri = new Uri(authUrl);
Uri callbackUri = new Uri(redirectUrl);
WebAuthenticatorResult result;
try
{
result = await WebAuthenticator.AuthenticateAsync(new WebAuthenticatorOptions
{
Url = authUri,
CallbackUrl = callbackUri,
PrefersEphemeralWebBrowserSession = true
});
}
catch (TaskCanceledException)
{
// 'Not' an error. The user simply cancelled this op.
return;
}
catch (Exception ex)
{
Debug.Fail(ex.Message);
return;
}
// Exchange the authorization code for an access token
var payload = new
{
code = result.Properties["code"],
redirectUri = redirectUrl,
clientId = clientId,
key = "web",
};
var jsonPayload = JsonConvert.SerializeObject(payload, Formatting.Indented);
var content = new StringContent(jsonPayload, Encoding.UTF8, "application/json");
using var httpClient = new HttpClient();
HttpResponseMessage? response = null;
string? error = null;
try
{
// Exchange token using secret stored on server.
// We are unable to attempt this. The async post causes this
// method to return, and when it does, the app crashes.
}
catch (Exception ex)
{
Debug.WriteLine(ex.Message);
if (response != null)
{
error = await response.Content.ReadAsStringAsync();
}
Debug.Fail(error ?? "null");
}
};
Value of jsonPayload indicates success
{
"code": "4/0AanRRrte8fELNx0CyzgsPzrGCo46TLvkp_JhQaG0ao8DMmVLySwN4_8KIfAXNiouGAqkrQ",
"redirectUri": "https://myfirebasedomain.com/auth",
"clientId": "123456789012-1ok9rauo969og7aljrnri1gesrr7l1b3.apps.googleusercontent.com",
"key": "web"
}
- Going up a level to wrap the
ContinueUserActivityfor exceptions. I can set a breakpoint onreturn result. The crash occurs if this method is allowed to run from that point.
[Register("AppDelegate")]
public class AppDelegate : MauiUIApplicationDelegate
{
protected override MauiApp CreateMauiApp() => MauiProgram.CreateMauiApp();
public override bool ContinueUserActivity(UIApplication application, NSUserActivity userActivity, UIApplicationRestorationHandler completionHandler)
{
bool result = false;
try
{
// Calling the BC is what causes the AuthenticateAsync task to complete.
result = base.ContinueUserActivity(application, userActivity, completionHandler);
}
catch (Exception)
{
// NO exception being caught here.
}
return result;
}
}
My question:
AFAIK I’m doing everything right, but can anyone spot any reason for the crash? I’m inclined to log it as a bug against WebAuthenticator for iOS, but before I do anything dumb please “check my work!”
Crash Log (iPhone 11 physical device)
Loaded assembly: Anonymously Hosted DynamicMethods Assembly [External]
INFO: 0x1a3be2db0 - /System/Library/PrivateFrameworks/UIKitCore.framework/UIKitCore : <redacted>
INFO: 0x1a390977c - /System/Library/PrivateFrameworks/UIKitCore.framework/UIKitCore : __UIVIEW_IS_EXECUTING_ANIMATION_COMPLETION_BLOCK__
INFO: 0x1a3c6677c - /System/Library/PrivateFrameworks/UIKitCore.framework/UIKitCore : <redacted>
INFO: 014e7888 - /private/var/containers/Bundle/Application/0D3ED65C-DDCD-40D0-A24A-BE6EDA007591/IVSoftware.Maui.EchoesSyncProxy.app/IVSoftware.Maui.EchoesSyncProxy : xamarin_get_original_working_directory_path
0x101842cdc - /private/var/containers/Bundle/Application/0D3ED65C-DDCD-40D0-A24A-BE6EDA007591/IVSoftware.Maui.EchoesSyncProxy.app/IVSoftware.Maui.EchoesSyncProxy : AppleCryptoNative_X509ImportCollection
0x1c72e0de8 - /usr/lib/dyld : <redacted>
=================================================================
Basic Fault Address Reporting
=================================================================
Memory around native instruction pointer (0x19e5d634c):0x19e5d633c 21 20 37 91 30 06 00 14 00 00 00 ea 6d ff ff 54 ! 7.0.......m..T
0x19e5d634c 10 00
INFO: 0x19e5d635c 30 04 00 36 11
INFO: 0x1a3abee00 - /System/Library/PrivateFrameworks/UIKitCore.framework/UIKitCore : <redacted>
INFO: 0x1a3c02410 - /System/Library/PrivateFrameworks/UIKitCore.framework/UIKitCore : <redacted>
INFO: 0x1a3908434 - /System/Library/PrivateFrameworks/UIKitCore.framework/UIKitCore : <redacted>
INFO: 0x1a3886350 - /System/Library/PrivateFrameworks/UIKitCore.framework/UIKitCore : <redacted>
INFO: Disposing input and output streams...
INFO: 0x1a10d5bbc - /System/Library/Frameworks/CoreFoundation.framework/CoreFoundation : <redacted>
0x1a10d21b0 - /System/Library/Frameworks/CoreFoundation.framework/CoreFoundation : <redacted>
0x1a1124274 - /System/Library/Frameworks/CoreFoundation.framework/CoreFoundation : CFRunLoopRunSpecific
INFO: 0x1a38863c0 - /System/Library/PrivateFrameworks/UIKitCore.framework/UIKitCore : <redacted>
INFO: 0x1a2c47008 - /System/Library/Frameworks/QuartzCore.framework/QuartzCore : <redacted>
INFO: 0x1a3908434 - /System/Library/PrivateFrameworks/UIKitCore.framework/UIKitCore : <redacted>
INFO: 0x1a3c02410 - /System/Library/PrivateFrameworks/UIKitCore.framework/UIKitCore : <redacted>
INFO: 0x1a3c02790 - /System/Library/PrivateFrameworks/UIKitCore.framework/UIKitCore : <redacted>
INFO: 0x1a3886350 - /System/Library/PrivateFrameworks/UIKitCore.framework/UIKitCore : <redacted>
INFO: 0x1a3909718 - /System/Library/PrivateFrameworks/UIKitCore.framework/UIKitCore : <redacted>
INFO: 0x1a3ac1944 - /System/Library/PrivateFrameworks/UIKitCore.framework/UIKitCore : <redacted>
INFO: 0x1c4e37488 - /System/Library/Frameworks/SafariServices.framework/SafariServices : <redacted>
INFO: 0x1a3abee00 - /System/Library/PrivateFrameworks/UIKitCore.framework/UIKitCore : <redacted>
INFO: 0x1017efa50 - /private/var/containers/Bundle/Application/0D3ED65C-DDCD-40D0-A24A-BE6EDA007591/IVSoftware.Maui.EchoesSyncProxy.app/IVSoftware.Maui.EchoesSyncProxy : AppleCryptoNative_X509ImportCollection
0x1017d1d0c - /private/var/containers/Bundle/Application/0D3ED65C-DDCD-40D0-A24A-BE6EDA007591/IVSoftware.Maui.EchoesSyncProxy.app/IVSoftware.Maui.EchoesSyncProxy : AppleCryptoNative_X509ImportCollection
0x22bba8ca8 - /usr/lib/system/libsystem_platform.dylib : <redacted>
INFO:
=================================================================
Native Crash Reporting
=================================================================
INFO: Got a SIGSEGV while executing native code. This usually indicates
a fatal error in the mono runtime or one of the native libraries
used by your application.
=================================================================
=================================================================
Native stacktrace:
=================================================================
INFO: 0x101804b64 - /private/var/containers/Bundle/Application/0D3ED65C-DDCD-40D0-A24A-BE6EDA007591/IVSoftware.Maui.EchoesSyncProxy.app/IVSoftware.Maui.EchoesSyncProxy : AppleCryptoNative_X509ImportCollection
INFO: 0x1a8e0bfa8 - /usr/lib/system/libdispatch.dylib : <redacted>
0x1a8e1aa34 - /usr/lib/system/libdispatch.dylib : <redacted>
INFO: 0x1a8e1a64c - /usr/lib/system/libdispatch.dylib : _dispatch_main_queue_callback_4CF
INFO: 0x1014e7888 - /private/var/containers/Bundle/Application/0D3ED65C-DDCD-40D0-A24A-BE6EDA007591/IVSoftware.Maui.EchoesSyncProxy.app/IVSoftware.Maui.EchoesSyncProxy : xamarin_get_original_working_directory_path
0x101842cdc - /private/var/containers/Bundle/Application/0D3ED65C-DDCD-40D0-A24A-BE6EDA007591/IVSoftware.Maui.EchoesSyncProxy.app/IVSoftware.Maui.EchoesSyncProxy : AppleCryptoNative_X509ImportCollection
0x1c72e0de8 - /usr/lib/dyld : <redacted>
Exiting early due to double fault.
INFO: 0x1a1124274 - /System/Library/Frameworks/CoreFoundation.framework/CoreFoundation : CFRunLoopRunSpecific
0x1ee26d4c0 - /System/Library/PrivateFrameworks/GraphicsServices.framework/GraphicsServices : GSEventRunModal
0x1a3c6677c - /System/Library/PrivateFrameworks/UIKitCore.framework/UIKitCore : <redacted>
INFO: 0x1a388ce64 - /System/Library/PrivateFrameworks/UIKitCore.framework/UIKitCore : UIApplicationMain
0x1014bc5f4 - /private/var/containers/Bundle/Application/0D3ED65C-DDCD-40D0-A24A-BE6EDA007591/IVSoftware.Maui.EchoesSyncProxy.app/IVSoftware.Maui.EchoesSyncProxy : xamarin_UIApplicationMain
0x101815404 - /private/var/containers/Bundle/Application/0D3ED65C-DDCD-40D0-A24A-BE6EDA007591/IVSoftware.Maui.EchoesSyncProxy.app/IVSoftware.Maui.EchoesSyncProxy : AppleCryptoNative_X509ImportCollection
0x101813d04 - /private/var/containers/Bundle/Application/0D3ED65C-DDCD-40D0-A24A-BE6EDA007591/IVSoftware.Maui.EchoesSyncProxy.app/IVSoftware.Maui.EchoesSyncProxy : AppleCryptoNative_X509ImportCollection
0x101808714 - /private/var/containers/Bundle/Application/0D3ED65C-DDCD-40D0-A24A-BE6EDA007591/IVSoftware.Maui.EchoesSyncProxy.app/IVSoftware.Maui.EchoesSyncProxy : AppleCryptoNative_X509ImportCollection
0x1018062ac - /private/var/containers/Bundle/Application/0D3ED65C-DDCD-40D0-A24A-BE6EDA007591/IVSoftware.Maui.EchoesSyncP
INFO: 0x1a2c47008 - /System/Library/Frameworks/QuartzCore.framework/QuartzCore : <redacted>
0x1a8e0bfa8 - /usr/lib/system/libdispatch.dylib : <redacted>
0x1a8e1aa34 - /usr/lib/system/libdispatch.dylib : <redacted>
0x1a8e1a64c - /usr/lib/system/libdispatch.dylib : _dispatch_main_queue_callback_4CF
0x1a10d5bbc - /System/Library/Frameworks/CoreFoundation.framework/CoreFoundation : <redacted>
0x1a10d21b0 - /System/Library/Frameworks/CoreFoundation.framework/CoreFoundation : <redacted>
INFO: 0x1a38863c0 - /System/Library/PrivateFrameworks/UIKitCore.framework/UIKitCore : <redacted>
INFO: 0x1a390977c - /System/Library/PrivateFrameworks/UIKitCore.framework/UIKitCore : __UIVIEW_IS_EXECUTING_ANIMATION_COMPLETION_BLOCK__
INFO: 0x1a3909718 - /System/Library/PrivateFrameworks/UIKitCore.framework/UIKitCore : <redacted>
INFO: roxy.app/IVSoftware.Maui.EchoesSyncProxy : AppleCryptoNative_X509ImportCollection
0x1017d4e84 - /private/var/containers/Bundle/Application/0D3ED65C-DDCD-40D0-A24A-BE6EDA007591/IVSoftware.Maui.EchoesSyncProxy.app/IVSoftware.Maui.EchoesSyncProxy : AppleCryptoNative_X509ImportCollection
0x10177c548 - /private/var/containers/Bundle/Application/0D3ED65C-DDCD-40D0-A24A-BE6EDA007591/IVSoftware.Maui.EchoesSyncProxy.app/IVSoftware.Maui.EchoesSyncProxy : AppleCryptoNative_X509ImportCollection
0x101782844 - /private/var/containers/Bundle/Application/0D3ED65C-DDCD-40D0-A24A-BE6EDA007591/IVSoftware.Maui.EchoesSyncProxy.app/IVSoftware.Maui.EchoesSyncProxy : AppleCryptoNative_X509ImportCollection
0x1017da4a0 - /private/var/containers/Bundle/Application/0D3ED65C-DDCD-40D0-A24A-BE6EDA007591/IVSoftware.Maui.EchoesSyncProxy.app/IVSoftware.Maui.EchoesSyncProxy : AppleCryptoNative_X509ImportCollection
INFO: 0x1a3c02790 - /System/Library/PrivateFrameworks/UIKitCore.framework/UIKitCore : <redacted>
INFO: 0x1a3ac1944 - /System/Library/PrivateFrameworks/UIKitCore.framework/UIKitCore : <redacted>
INFO: 0x1a3be2db0 - /System/Library/PrivateFrameworks/UIKitCore.framework/UIKitCore : <redacted>
INFO: at UIKit.UIApplication:Main <0x00152>
at GoogleDriveLocalSyncProxy.Maui.TestProject.Program:Main <0x0002c>
at <Module>:runtime_invoke_direct_void_string[] <0x0007e>
at <unknown> <0x00000>
=================================================================
=================================================================
Native Crash Reporting
=================================================================
Got a SIGSEGV while executing native code. This usually indicates
a fatal error in the mono runtime or one of the native libraries
used by your application.
=================================================================
An error has occurred in the native fault reporting. Some diagnostic information will be unavailable.
INFO:
=================================================================
Native stacktrace:
=================================================================
0x101804b64 - /private/var/containers/Bundle/Application/0D3ED65C-DDCD-40D0-A24A-BE6EDA007591/IVSoftware.Maui.EchoesSyncProxy.app/IVSoftware.Maui.EchoesSyncProxy : AppleCryptoNative_X509ImportCollection
0x1017efa50 - /private/var/containers/Bundle/Application/0D3ED65C-DDCD-40D0-A24A-BE6EDA007591/IVSoftware.Maui.EchoesSyncProxy.app/IVSoftware.Maui.EchoesSyncProxy : AppleCryptoNative_X509ImportCollection
0x1017d1d0c - /private/var/containers/Bundle/Application/0D3ED65C-DDCD-40D0-A24A-BE6EDA007591/IVSoftware.Maui.EchoesSyncProxy.app/IVSoftware.Maui.EchoesSyncProxy : AppleCryptoNative_X509ImportCollection
INFO: ...
=================================================================
Managed Stacktrace:
=================================================================
at <unknown> <0xffffffff>
at UIKit.UIApplication:xamarin_UIApplicationMain <0x000b8>
at UIKit.UIApplication:UIApplicationMain <0x0006e>
INFO: 0x22bba8ca8 - /usr/lib/system/libsystem_platform.dylib : <redacted>
0x1c4e37488 - /System/Library/Frameworks/SafariServices.framework/SafariServices : <redacted>
INFO: `..T. .......
INFO: fe 77 d3 91 fe ff b4 3f 06 00 f1 0..6..w.....?...
INFO: ..@...}[email protected]
INFO: 40 f9 02 82 7d 92 51 10 40 f9 31 03 10 36
INFO: 0x1018062ac - /private/var/containers/Bundle/Application/0D3ED65C-DDCD-40D0-A24A-BE6EDA007591/IVSoftware.Maui.EchoesSyncProxy.app/IVSoftware.Maui.EchoesSyncProxy : AppleCryptoNative_X509ImportCollection
0x1017d4e84 - /private/var/containers/Bundle/Application/0D3ED65C-DDCD-40D0-A24A-BE6EDA007591/IVSoftware.Maui.EchoesSyncProxy.app/IVSoftware.Maui.EchoesSyncProxy : AppleCryptoNative_X509ImportCollection
0x10177c548 - /private/var/containers/Bundle/Application/0D3ED65C-DDCD-40D0-A24A-BE6EDA007591/IVSoftware.Maui.EchoesSyncProxy.app/IVSoftware.Maui.EchoesSyncProxy : AppleCryptoNative_X509ImportCollection
0x101782844 - /private/var/containers/Bundle/Application/0D3ED65C-DDCD-40D0-A24A-BE6EDA007591/IVSoftware.Maui.EchoesSyncProxy.app/IVSoftware.Maui.EchoesSyncProxy : AppleCryptoNative_X509ImportCollection
0x1017da4a0 - /private/var/containers/Bundle/Application/0D3ED65C-DDCD-40D0-A24A-BE6EDA007591/IVSoftware.Maui.EchoesSyncProxy.app/IVSoftware.Maui.EchoesSyncProxy : AppleCryptoNative_X509ImportCollection
0x1
INFO: 0x1a388ce64 - /System/Library/PrivateFrameworks/UIKitCore.framework/UIKitCore : UIApplicationMain
0x1014bc5f4 - /private/var/containers/Bundle/Application/0D3ED65C-DDCD-40D0-A24A-BE6EDA007591/IVSoftware.Maui.EchoesSyncProxy.app/IVSoftware.Maui.EchoesSyncProxy : xamarin_UIApplicationMain
0x101815404 - /private/var/containers/Bundle/Application/0D3ED65C-DDCD-40D0-A24A-BE6EDA007591/IVSoftware.Maui.EchoesSyncProxy.app/IVSoftware.Maui.EchoesSyncProxy : AppleCryptoNative_X509ImportCollection
0x101813d04 - /private/var/containers/Bundle/Application/0D3ED65C-DDCD-40D0-A24A-BE6EDA007591/IVSoftware.Maui.EchoesSyncProxy.app/IVSoftware.Maui.EchoesSyncProxy : AppleCryptoNative_X509ImportCollection
0x101808714 - /private/var/containers/Bundle/Application/0D3ED65C-DDCD-40D0-A24A-BE6EDA007591/IVSoftware.Maui.EchoesSyncProxy.app/IVSoftware.Maui.EchoesSyncProxy : AppleCryptoNative_X509ImportCollection
INFO: 0x1ee26d4c0 - /System/Library/PrivateFrameworks/GraphicsServices.framework/GraphicsServices : GSEventRunModal
INFO:
0x19e5d636c 60 02 00 54 11 20 e0 d2 11 02 11 cb e1 03 10 aa
INFO: Closing debug connection from remote debugger (TCP)
INFO: Closing debug connection from device (USB)
The app has been terminated.
INFO: Disposing input and output streams...
INFO: Disposing console and debugger streams...
ERROR: An error occurred while writing to the debug stream. Details: ObjectDisposed_Generic
ObjectDisposed_ObjectName_Name, UsbStream