Skip to content

Protect the fallback temporary home directory by enforcing and checking its file mode on Unix platforms #27985

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
Dongbo Wang (daxian-dbw) merged 1 commit into from
Sep 22, 2026
Merged

Protect the fallback temporary home directory by enforcing and checking its file mode on Unix platforms #27985

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
12 changes: 11 additions & 1 deletion src/System.Management.Automation/CoreCLR/CorePsPlatform.cs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -280,7 +280,17 @@ private static string GetHomeOrCreateTempHome()
try
{
s_tempHome = Path.Combine(Path.GetTempPath(), StringUtil.Format(tempHomeFolderName, Environment.UserName));
Directory.CreateDirectory(s_tempHome);

// Create the temporary home directory with the user-only permission.
UnixFileMode userOnlyMode = UnixFileMode.UserRead | UnixFileMode.UserWrite | UnixFileMode.UserExecute;
var dirInfo = Directory.CreateDirectory(s_tempHome, userOnlyMode);
if (dirInfo.UnixFileMode != userOnlyMode)
{
// The permission is not as expected, which indicates the directory may be pre-created by a different user.
// Throw an exception and fail PowerShell in this case for security reason.
throw new InvalidOperationException(
StringUtil.Format(CoreClrStubResources.TempHomeDirectoryUnsafePermission, s_tempHome));
}
}
catch (UnauthorizedAccessException)
{
Expand Down
4 changes: 4 additions & 0 deletions src/System.Management.Automation/resources/CoreClrStubResources.resx
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -138,4 +138,8 @@
<data name="UnknownErrorNumber" xml:space="preserve">
<value>Unknown error "{0}".</value>
</data>
<data name="TempHomeDirectoryUnsafePermission" xml:space="preserve">
<value>The temporary HOME directory '{0}' already exists but does not have the expected user-only permission. It may have been created by a different user, which is a potential security risk. PowerShell will not start until this directory is removed, its permission is corrected, or the 'HOME' environment variable is set.</value>
<comment>{StrContains="HOME"}</comment>
</data>
</root>
Loading