syscall, os/exec: Support running child process as different user on Windows

[mappu]

What version of Go are you using (go version)?

$ go version
go version go1.13.4 windows/amd64

Does this issue reproduce with the latest release?

n/a

What operating system and processor architecture are you using (go env)?

n/a

What did you do?

Try to launch a process as a different user. Found syscall.Credential can be supplied as a SysProcAttr to exec.Cmd.

What did you expect to see?

Ability to launch process as different user, on all supported OSes.

What did you see instead?

syscall.Credential only supports UID/GID and only works on Unix-like systems. There's no option for Windows (based on either CreateProcessWithLogonW call, or LogonUser/CreateProcessAsUserW pair call).

[acln0]

On Windows, syscall.SysProcAttr is this: https://golang.org/pkg/syscall/?GOOS=windows#SysProcAttr

I think you can load the appropriate DLL for LogonUser (see https://godoc.org/golang.org/x/sys/windows#NewLazyDLL), call the function, which grants a syscall.Token, then use it with SysProcAttr.

[toothrot]

Thanks @acln0, I think you're right.

I believe this is a duplicate of #21105. I think the associated CL, golang.org/cl/75253 includes an example of this. I'll close this as a duplicate, but please let me know if I am mistaken.