Prep filter for NtQueryDirectoryFile

[JeremyKuhne]

NtQueryDirectoryFile should always be able to take filters as long as they are properly escaped for how we'll do our matching. The special directories . and .. get blocked, but anything outside of that should be fair game.

cc: @stephentoub

[Copilot]

Pull request overview

This PR refactors how filter expressions are prepared for NtQueryDirectoryFile on Windows. Instead of conservatively rejecting patterns that might be unsafe for OS-level filtering, it now escapes special DOS wildcard characters to ensure any expression (except . and ..) can be safely passed to the OS.

Changes:

• Adds expression preprocessing logic to escape special characters (\, ", <, >) for MatchType.Simple patterns
• Replaces the conservative IsSafePatternForOSFilter check with a simple null check, allowing more patterns to use OS-level filtering
• Removes the IsSafePatternForOSFilter method and its associated SearchValues helper

[stephentoub]

@JeremyKuhne there are 73 relevant test failures, e.g.

    System.IO.Tests.Directory_GetFiles_str_str.WindowsSearchPatternWhitespace [FAIL]
      System.IO.IOException : The filename, directory name, or volume label syntax is incorrect. : 'C:\h\w\B61E099C\t\#Directory_GetFiles_str_str_u2cqwqyk.mit'.
      Stack Trace:
        /_/src/libraries/System.Private.CoreLib/src/System/IO/Enumeration/FileSystemEnumerator.Windows.cs(282,0): at System.IO.Enumeration.FileSystemEnumerator`1.MoveNext()
        /_/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/List.cs(85,0): at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
        /_/src/libraries/System.Private.CoreLib/src/System/IO/Directory.cs(174,0): at System.IO.Directory.GetFiles(String path, String searchPattern, EnumerationOptions enumerationOptions)
        /_/src/libraries/System.Private.CoreLib/src/System/IO/Directory.cs(168,0): at System.IO.Directory.GetFiles(String path, String searchPattern)
        /_/src/libraries/System.Runtime/tests/System.IO.FileSystem.Tests/Directory/GetFiles.cs(96,0): at System.IO.Tests.Directory_GetFiles_str_str.GetEntries(String path, String searchPattern)
        /_/src/libraries/System.Runtime/tests/System.IO.FileSystem.Tests/Directory/GetFileSystemEntries_str_str.cs(695,0): at System.IO.Tests.Directory_GetFileSystemEntries_str_str.WindowsSearchPatternWhitespace()
           at System.RuntimeMethodHandle.InvokeMethod(ObjectHandleOnStack target, Void** arguments, ObjectHandleOnStack sig, BOOL isConstructor, ObjectHandleOnStack result)
           at System.RuntimeMethodHandle.InvokeMethod(ObjectHandleOnStack target, Void** arguments, ObjectHandleOnStack sig, BOOL isConstructor, ObjectHandleOnStack result)
        /_/src/coreclr/System.Private.CoreLib/src/System/Reflection/MethodBaseInvoker.CoreCLR.cs(36,0): at System.Reflection.MethodBaseInvoker.InterpretedInvoke_Method(Object obj, IntPtr* args)
        /_/src/libraries/System.Private.CoreLib/src/System/Reflection/RuntimeMethodInfo.cs(134,0): at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)

[jozkee]

I'm still confused about the FileName param in NtQueryDirectoryFile. I can't find anything backing that it follows similar rules to MatchType.Win32. How do we know that's the case?

[JeremyKuhne]

I'm still confused about the FileName param in NtQueryDirectoryFile. I can't find anything backing that it follows similar rules to MatchType.Win32. How do we know that's the case?

@jozkee Well, partially by looking at the sources when writing this all originally. :) https://learn.microsoft.com/openspecs/windows_protocols/ms-fsa/0b034646-4e23-4874-8488-2adac231ff23 talks about it. RtlIsNameInExpression is what everything calls (and we literally copy in FileSystemName), but it isn't particularly coherently documented. You can look at the implementation for FindFirstFile to see that it translates to these special characters.

[Copilot]

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

[stephentoub]

LGTM. Thanks!

[Copilot]

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

[jozkee]

Thanks, @JeremyKuhne.

[jozkee]

nit

Suggested change

	ReadOnlySpan<char> charsToEscape = ['\\', '"', '<', '>'];
	int i = span.IndexOfAny(charsToEscape);
	int i = span.IndexOfAny("\\\"<>");

[jozkee]

If this test doesn't fail, I guess we could remove if (!PlatformDetection.IsWindows10Version20348OrGreater) from the other tests too.

[jozkee]

/ba-g infrastructure errors