SignTool: Process.WaitForExit() calls can block indefinitely

[MichaelSimons]

Summary

Several process execution call sites in Microsoft.DotNet.SignTool use Process.WaitForExit() without a timeout, which can block indefinitely if the child process hangs. This could cause signing builds to hang with no diagnostics.

Affected Locations:

All in src/Microsoft.DotNet.SignTool/src/:

File	Method	What it runs
ZipData.cs	RunPkgProcess	dotnet exec for pkg tool
ZipData.cs	RunTarProcess	dotnet exec for tar tool (.NET Framework)
ZipData.cs	RunExternalProcess	bash for cpio/RPM operations
BatchSignUtil.cs	RunWixTool	cmd /c for WiX tools

Note: RealSignTool.RunMSBuild already handles this correctly using a configurable _dotnetTimeout with process.Kill() on timeout.

Suggested Approach

Consider consolidating process execution into a shared utility with:

• Configurable timeout (with a sensible default)
• Kill + wait on timeout
• Consistent logging of command, stdout, stderr, and exit code
• Consistent error reporting

The existing Microsoft.Arcade.Common.Command / ICommand utility could be extended with timeout support (it also calls WaitForExit() without a timeout today), or the proven pattern from RealSignTool.RunMSBuild could be extracted into a reusable helper.