System.IO.FileSystem.AccessControl can't set ACLs on files with long paths

[hach-que]

Description

When attempting to set ACLs on a file with a long path on Windows, SetAccessControl throws ArgumentException: Invalid name:

Failed to grant Everyone full control of 'C:\ProgramData\UET\SDKs\Android-android-33-33.0.1-3.10.2.4988404-25.1.8937393-jdk-11.0.19+7\Sdk\cmdline-tools\lib\external\com\google\guava\listenablefuture\9999.0-empty-to-avoid-conflict-with-guava\listenablefuture-9999.0-empty-to-avoid-conflict-with-guava.jar'. Exception was: System.ArgumentException: Invalid name. (Parameter 'name')    at System.Security.AccessControl.NativeObjectSecurity.Persist(String name, SafeHandle handle, AccessControlSections includeSections, Object exceptionContext)    at System.Security.AccessControl.FileSystemSecurity.Persist(String fullPath)

Reproduction Steps

var dacl = file.GetAccessControl(AccessControlSections.Access);
dacl.AddAccessRule(new FileSystemAccessRule(_everyoneWindows.Value, FileSystemRights.FullControl, AccessControlType.Allow));
file.SetAccessControl(dacl);

where file is a FileInfo pointing to a file with a long path.

Expected behavior

SetAccessControl should work with long paths on Windows.

Actual behavior

SetAccessControl throws ArgumentException: Invalid name.

Regression?

No response

Known Workarounds

I tried to workaround this with this code:

var dacl = new FileSecurity(@"\\?\" + file.FullName, AccessControlSections.Access);
dacl.AddAccessRule(new FileSystemAccessRule(_everyoneWindows.Value, FileSystemRights.FullControl, AccessControlType.Allow));
dacl.Persist(@"\\?\" + file.FullName);

however, Persist is internal/protected and not available to user code. You also can't inherit from FileSystemSecurity to access the protected method, as all constructors on that class are internal.

Configuration

.NET 7

Other information

No response

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Issue Details

---

Description

When attempting to set ACLs on a file with a long path on Windows, SetAccessControl throws ArgumentException: Invalid name:

Failed to grant Everyone full control of 'C:\ProgramData\UET\SDKs\Android-android-33-33.0.1-3.10.2.4988404-25.1.8937393-jdk-11.0.19+7\Sdk\cmdline-tools\lib\external\com\google\guava\listenablefuture\9999.0-empty-to-avoid-conflict-with-guava\listenablefuture-9999.0-empty-to-avoid-conflict-with-guava.jar'. Exception was: System.ArgumentException: Invalid name. (Parameter 'name')    at System.Security.AccessControl.NativeObjectSecurity.Persist(String name, SafeHandle handle, AccessControlSections includeSections, Object exceptionContext)    at System.Security.AccessControl.FileSystemSecurity.Persist(String fullPath)

Reproduction Steps

var dacl = file.GetAccessControl(AccessControlSections.Access);
dacl.AddAccessRule(new FileSystemAccessRule(_everyoneWindows.Value, FileSystemRights.FullControl, AccessControlType.Allow));
file.SetAccessControl(dacl);

where file is a FileInfo pointing to a file with a long path.

Expected behavior

SetAccessControl should work with long paths on Windows.

Actual behavior

SetAccessControl throws ArgumentException: Invalid name.

Regression?

No response

Known Workarounds

I tried to workaround this with this code:

var dacl = new FileSecurity(@"\\?\" + file.FullName, AccessControlSections.Access);
dacl.AddAccessRule(new FileSystemAccessRule(_everyoneWindows.Value, FileSystemRights.FullControl, AccessControlType.Allow));
dacl.Persist(@"\\?\" + file.FullName);

however, Persist is internal/protected and not available to user code. You also can't inherit from FileSystemSecurity to access the protected method, as all constructors on that class are internal.

Configuration

.NET 7

Other information

No response

Author:	hach-que
Assignees:	-
Labels:	area-System.IO
Milestone:	-

[adamsitnik]

Triage: I've marked this issue as help wanted. Whoever wants to work on it should attach a debugger and see which sys-call is being used in that scenario:

• the one that takes a name:

  runtime/src/libraries/System.Security.AccessControl/src/System/Security/AccessControl/Win32.cs

  Line 278 in 35fc3c0

  errorCode = (int)Interop.Advapi32.SetSecurityInfoByName(name, (uint)type, unchecked((uint)securityInformation), OwnerBinary, GroupBinary, DaclBinary, SaclBinary);

• the one that takes a handle:

  runtime/src/libraries/System.Security.AccessControl/src/System/Security/AccessControl/Win32.cs

  Line 290 in 35fc3c0

  errorCode = (int)Interop.Advapi32.SetSecurityInfoByHandle(handle, (uint)type, (uint)securityInformation, OwnerBinary, GroupBinary, DaclBinary, SaclBinary);

I suspect it's the one that takes the string name. In such case we need to ensure that we call the sys-call in the right way, if we do and it's impossible to get it working we should most likely open the file on our own via File.OpenHandle and use the sys-call that accepts a file handle.

[karakasa]

the call hierarchy is:

• FileSystemAclExtensions.SetAccessControl(this FileInfo)
• FileSystemSecurity.Persist(string name)
• NativeObjectSecurity.Persist (handle is null)
• Win32.SetSecurityInfo (handle is null)
• Interop.Advapi32.SetSecurityInfoByName when handle is null

It seems the file handle is never created, if the security object is constructed via name (file location).

I think we may add System.IO.PathInternal.EnsureExtendedPrefixIfNeeded to FileSystemSecurity.Persist(string) just as it does in the constructor.

Another workaround would be FileSystemAclExtensions.SetAccessControl(this FileStream fileStream, FileSecurity fileSecurity) because it calls FileSystemSecurity.Persist(SafeFileHandle)

I also noticed that the Security tab is missing for long-named files in explorer... 🤔