Fix WindowsCertificateManager to correctly detect user cancellation of trust dialog#66604
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Fix WindowsCertificateManager to correctly detect user cancellation of trust dialog#66604
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…ation Agent-Logs-Url: https://github.com/dotnet/aspnetcore/sessions/d251b35d-591f-48d3-9a0f-38022f445c36 Co-authored-by: Youssef1313 <31348972+Youssef1313@users.noreply.github.com>
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[WIP] Fix cancellation reporting in WindowsCertificateManager
Fix WindowsCertificateManager to correctly detect user cancellation of trust dialog
May 6, 2026
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Pull request overview
This PR updates Windows certificate trust handling to correctly recognize when a user cancels the Windows trust prompt, so the cancellation can be translated into UserCancelledTrustException instead of surfacing as an unhandled CryptographicException.
Changes:
- Updates the
CryptographicExceptionfilter inWindowsCertificateManager.TrustCertificateCoreto detect the cancellation code based on the exception HRESULT’s encoded structure. - Adds inline commentary explaining how the HRESULT is interpreted for this check.
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| // https://msdn.microsoft.com/library/cc231198.aspx documents how HResult is formed. | ||
| // In short, the error code is only the 2 least significant bytes. | ||
| catch (CryptographicException exception) when ((exception.HResult & 0xFFFF) == UserCancelledErrorCode) |
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| // https://msdn.microsoft.com/library/cc231198.aspx documents how HResult is formed. | ||
| // In short, the error code is only the 2 least significant bytes. | ||
| catch (CryptographicException exception) when ((exception.HResult & 0xFFFF) == UserCancelledErrorCode) | ||
| { | ||
| Log.WindowsCertificateTrustCanceled(); | ||
| throw new UserCancelledTrustException(); |
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WindowsCertificateManager.TrustCertificateCorewas comparingexception.HResultagainst the raw Win32 error code (ERROR_CANCELLED = 1223 = 0x4C7) instead of its HRESULT-encoded form. SinceHResultusesHRESULT_FROM_WIN32encoding (0x80070000 | win32code), the check never matched, causing user cancellations to surface as unhandled exceptions rather than being caught and converted toUserCancelledTrustException.Description
UserCancelledErrorCodefrom1223tounchecked((int)0x800704C7)— the HRESULT encoding ofERROR_CANCELLEDNote:
Exception.HResultalways returns the HRESULT-encoded value (0x8007xxxxfor Win32 errors), never the raw Win32 error code. The original value1223was therefore dead code — it could never matchexception.HResult. Replacing it withunchecked((int)0x800704C7)is the correct fix; retaining1223alongside the new value would leave unreachable dead code.