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ExtendedProcessFailedEventArgs.md #3824

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85 changes: 85 additions & 0 deletions specs/ExtendedProcessFailedEventArgs.md
Original file line number Diff line number Diff line change
@@ -0,0 +1,85 @@

Title
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===

# Background
Code integrity is a feature of Windows that verifies the authenticity and integrity of the code that runs on the system. It helps protect it from malware, tampering, and unauthorized changes. Code integrity checks the digital signatures of the files that are loaded into memory, and prevents any file that does not have a valid signature from running in WebView2. We are extending ProcessFailedEventArgs with BlockedFile property which caused webview2 process to exit with code STATUS_INVALID_IMAGE_HASH.
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# Examples

```c#
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Remove the leading spaces here to let the backticks get interpreted correctly so this shows as a formatted code block.

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Please fix.

/// This is an event handler for our CoreWebView2's ProcessFailedEvent
private void CoreWebView2_ProcessFailed(object sender, CoreWebView2ProcessFailedEventArgs e)
{
if (e.ExitCode == -1073740760 /*STATUS_INVALID_IMAGE_HASH*/)
{
SendTelemetry(e.BlockedFile);
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}
}
```

```cpp
CHECK_FAILURE(m_webView->add_ProcessFailed(
Callback<ICoreWebView2ProcessFailedEventHandler>(
[this](ICoreWebView2* sender, ICoreWebView2ProcessFailedEventArgs* argsRaw)
-> HRESULT {
wil::com_ptr<ICoreWebView2ProcessFailedEventArgs> args = argsRaw;
int exit_code;
CHECK_FAILURE(args->get_ExitCode(&exit_code));
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get_ExitCode is a method on ICoreWebView2ProcessFailedEventArgs2, so would have to QI to it first.

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Please fix.


if (exit_code == -1073740760 /*STATUS_INVALID_IMAGE_HASH*/) {
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FailureSourceModulePath doesn't appear to be specific to STATUS_INVALID_IMAGE_HASH or Windows Code Integrity. Is the expectation that this string could be populated in other failure cases, but STATUS_INVALID_IMAGE_HASH is the only case when we're currently promising it will always be populated?

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Yes that is exactly what I was thinking.

wil::unique_cotaskmem_string blockedFile;
CHECK_FAILURE(arg_blocked_file->get_BlockedFile(&blockedFile));

SendTelemetry(blockedFile);
}

return S_OK;
}
```


# API Details

```
/// A continuation of the ICoreWebView2ProcessFailedEventArgs2 interface
/// fot getting blocked file for code integrity process failures.
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[uuid(a9fc1af8-f934-4f0f-a788-7be0808c329b), object, pointer_default(unique)]
interface ICoreWebView2ProcessFailedEventArgs : IUnknown {
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Um, we already have a ICoreWebView2ProcessFailedEventArgs. and even a ICoreWebView2ProcessFailedEventArgs2. Shouldn't this be ICoreWebView2ProcessFailedEventArgs3?

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Please fix. Yes, should be ICoreWebView2ProcessFailedEventArgs3 and it should be derived from ICoreWebView2ProcessFailedEventArgs2

/// Code Integrity is a feature that verifies the integrity and
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/// authenticity of dynamic-link libraries (DLLs)
/// on Windows systems. It ensures that only trusted
/// code can run on the system and prevents unauthorized or
/// malicious modifications.
/// When ProcessFailed occurred due to a failed Code Integrity check,
/// this property returns the name of the blocked file that was prevented from
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/// loading on the system.
/// The webview2 process which tried to load blocked DLL will fail with
/// exit code STATUS_INVALID_IMAGE_HASH(-1073740760).
/// A file can be blocked for various
/// reasons, such as:
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May be out of scope, but will the developer ever need to know the more specific reason?

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I don't believe this is required and we can look into adding it if necessary in the future. @vbryh-msft or @aluhrs13 can comment otherwise.

/// - It has an invalid or missing signature that does
/// not match the publisher or signer of the file.
/// - It has been tampered with or corrupted by malware or other software.
/// - It has been blocklisted by an administrator or a security policy.
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Suggested change
/// - It has been blocklisted by an administrator or a security policy.
/// - It has been blocked by an administrator or a security policy.

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Please fix.

/// This property always will be empty if failure is not caused by
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/// STATUS_INVALID_IMAGE_HASH.
[propget] HRESULT BlockedFile([out, retval] LPWSTR* blockedFile);
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}
```

```c# (but really MIDL3)
namespace Microsoft.Web.WebView2.Core
{
runtimeclass CoreWebView2ProcessFailedEventArgs
{
// ICoreWebView2ProcessFailedEventArgs members continuation
[interface_name("Microsoft.Web.WebView2.Core.ICoreWebView2ProcessFailedEventArgs3")]
{
// ICoreWebView2ProcessFailedEventArgs3 members
String BlockedFile { get; };
}

}
}
```