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Custom AndroidMessageHandler.ServerCertificateCustomValidationCallback that returns false may cause application crash while debugging. #8608

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Custom AndroidMessageHandler.ServerCertificateCustomValidationCallback that returns false may cause application crash while debugging.#8608
Labels
Area: Mono.AndroidIssues with the Android API binding (Mono.Android.dll).need-attentionA xamarin-android contributor needs to review
Milestone
Under Consideration

Description

@anton-yashin
anton-yashin
opened on Dec 22, 2023

Android application type

.NET Android (net7.0-android, net8.0-android, etc.)

Affected platform version

VS2022 18.3 with .net 34.0.43/8.0.100

Description

When you using AndroidMessageHandler with ServerCertificateCustomValidationCallback that returns false while debugging you may get application crash.

Steps to Reproduce

  1. Create new android app with code like this
    Sample code:
try
{
    using (var ch = new AndroidMessageHandler())
    {
        ch.ServerCertificateCustomValidationCallback += (a, b, c, d) => false;
        using (var hc = new HttpClient(ch))
        {
            var result = await hc.GetAsync("https://github.com");
            // never get here
        }
    }
}
catch (Exception ex)
{
    // may be get here
    XDebug.WriteLine($"exception handled {ex.Message}");
}
  1. Run it several times. Two times in my case.
  2. Observe application crash.
    See sample project in attachment: UnhandledCertificateException.zip

Did you find any workaround?

No response

Relevant log output

No response

Activity

  1. anton-yashin
    added
    Area: App RuntimeIssues in `libmonodroid.so`.
    needs-triageIssues that need to be assigned.
    on Dec 22, 2023
  2. anton-yashin
    assigned
    grendello
    on Dec 22, 2023

  3. anton-yashin commented on Dec 22, 2023

    @anton-yashin
    anton-yashin
    on Dec 22, 2023
    Author

    You may run sample code more than one time to crash application. Debugger is required.

  4. jpobst commented on Dec 22, 2023

    @jpobst
    jpobst
    on Dec 22, 2023
    Contributor

    To be clear, the issue is that the exception isn't caught, correct?

    The exception is expected, but the catch handler isn't functioning.

  5. anton-yashin commented on Dec 22, 2023

    @anton-yashin
    anton-yashin
    on Dec 22, 2023
    Author

    With VS2022 17.8.3 debugger it's going to crash application, after second time running sample code. Without debugger seems works fine. There something strange happens.

  6. anton-yashin commented on Dec 22, 2023

    @anton-yashin
    anton-yashin
    on Dec 22, 2023
    Author

    With a debugger, it looks like a crash from an uncaught exception.

  7. anton-yashin
    changed the title [-]Java.Security.Cert.CertificateException when AndroidMessageHandler.ServerCertificateCustomValidationCallback is set and returns false.[/-] [+]Custom AndroidMessageHandler.ServerCertificateCustomValidationCallback that returns false may cause application crash while debugging.[/+] on Dec 23, 2023

  8. grendello commented on Jan 3, 2024

    @grendello
    grendello
    on Jan 3, 2024
    Contributor

    Please provide more information about the crash. We would need the following:

    Any messages VS shows in either its output/debug/etc panes and screenshots of popup boxes (if any) it produces.

    Full logcat of the application from the device/emulator. To record it, please follow the steps below:

    1. Open the VS Developer prompt. Do not start the application yet.
    2. Type the following commands one by one:
      1. adb shell setprop debug.mono.log default,assembly,mono_log_level=debug,mono_log_mask=all
      2. adb logcat -G 16M
      3. adb logcat -c
    3. Start the application from within VS and trigger the crash
    4. Back in the VS Developer prompt type: adb logcat -d > logcat.txt

    Please attach logcat.txt and the requested VS messages/screenshots. Thanks!

  9. grendello
    added
    need-infoIssues that need more information from the author.
    Area: Mono RuntimeMono-related issues: BCL bugs, AOT issues, etc.
    Area: DebuggerIssues using or interacting with the debugger.
    and removed
    Area: App RuntimeIssues in `libmonodroid.so`.
    needs-triageIssues that need to be assigned.
    on Jan 3, 2024

  10. anton-yashin commented on Jan 8, 2024

    @anton-yashin
    anton-yashin
    on Jan 8, 2024
    Author

    Here requested addtional info
    logcat.txt

  11. 14 remaining items

  12. simonrozsival
    removed their assignment
    on Feb 7, 2024

  13. gkarabin commented on Jun 14, 2024

    @gkarabin
    gkarabin
    on Jun 14, 2024

    My team seems to be running into this. Are there any other related tickets open?

    We are just getting organized to look into this. Is there anything we could do to help move things along?

  14. simonrozsival commented on Jun 15, 2024

    @simonrozsival
    simonrozsival
    on Jun 15, 2024
    Member

    This can't be easily fixed without additional runtime support.

    Would it be possible to raise the Java exception directly through some JNI helper in ServerCertificateCustomValidator without throwing it in C# first? Would we be able to avoid hitting the uncaught exception handler code?

  15. jonpryor
    added a commit that references this issue on Dec 4, 2024

    [generator] Remove `JNINativeWrapper.CreateDelegate` from bindings (#…

    356485e
  16. grendello
    removed their assignment
    on Mar 26, 2026
  17. simonrozsival
    added a commit that references this issue on Jul 1, 2026

    [tests] Ignore crashing ServerCertificateCustomValidationCallback tests

    47a26b3
  18. pull
    added a commit that references this issue on Jul 1, 2026

    [generator] Remove `JNINativeWrapper.CreateDelegate` from bindings (#…

    9f760b3
  19. simonrozsival
    added a commit that references this issue on Jul 6, 2026

    [tests] Stream on-device test results to MTP as they finish (#11833)

    41fb6ae
  20. jonathanpeppers
    added this to the Under Consideration milestone on Aug 13, 2026
  21. jonathanpeppers
    added
    possibly-staleIssues that are potentially no longer relevant.
    on Aug 13, 2026

  22. anton-yashin commented on Aug 14, 2026

    @anton-yashin
    anton-yashin
    on Aug 14, 2026
    Author

    Checked w 36.1.69/10.0.100. Works fine. Thanks :)

  23. anton-yashin
    closed this as completedon Aug 14, 2026
  24. dotnet-policy-service
    added
    need-attentionA xamarin-android contributor needs to review
    and removed
    possibly-staleIssues that are potentially no longer relevant.
    on Aug 14, 2026
  25. github-actions
    locked and limited conversation to collaborators on Sep 14, 2026
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