winrm

Command-line tool and library for Windows remote command execution in Go

Programming language: Go

License: Apache License 2.0

Tags: Networking    

README

WinRM for Go

Note: if you're looking for the winrm command-line tool, this has been splitted from this project and is available at winrm-cli

This is a Go library to execute remote commands on Windows machines through the use of WinRM/WinRS.

Note: this library doesn't support domain users (it doesn't support GSSAPI nor Kerberos). It's primary target is to execute remote commands on EC2 windows machines.

Contact

• Bugs: https://github.com/masterzen/winrm/issues

Getting Started

WinRM is available on Windows Server 2008 and up. This project natively supports basic authentication for local accounts, see the steps in the next section on how to prepare the remote Windows machine for this scenario. The authentication model is pluggable, see below for an example on using Negotiate/NTLM authentication (e.g. for connecting to vanilla Azure VMs) or Kerberos authentication (using domain accounts).

Note: This library only supports Golang 1.7+

Preparing the remote Windows machine for Basic authentication

This project supports only basic authentication for local accounts (domain users are not supported). The remote windows system must be prepared for winrm:

For a PowerShell script to do what is described below in one go, check Richard Downer's blog

On the remote host, a PowerShell prompt, using the Run as Administrator option and paste in the following lines:

    winrm quickconfig
    y
    winrm set winrm/config/service/Auth '@{Basic="true"}'
    winrm set winrm/config/service '@{AllowUnencrypted="true"}'
    winrm set winrm/config/winrs '@{MaxMemoryPerShellMB="1024"}'

N.B.: The Windows Firewall needs to be running to run this command. See Microsoft Knowledge Base article #2004640.

N.B.: Do not disable Negotiate authentication as the winrm command itself uses this for internal authentication, and you risk getting a system where winrm doesn't work anymore.

N.B.: The MaxMemoryPerShellMB option has no effects on some Windows 2008R2 systems because of a WinRM bug. Make sure to install the hotfix described Microsoft Knowledge Base article #2842230 if you need to run commands that use more than 150MB of memory.

For more information on WinRM, please refer to the online documentation at Microsoft's DevCenter.

Preparing the remote Windows machine for kerberos authentication

This project supports domain users via kerberos authentication. The remote windows system must be prepared for winrm:

On the remote host, a PowerShell prompt, using the Run as Administrator option and paste in the following lines:

            winrm quickconfig
            y
            winrm set winrm/config/service '@{AllowUnencrypted="true"}'
            winrm set winrm/config/winrs '@{MaxMemoryPerShellMB="1024"}'

All N.B points of "Preparing the remote Windows machine for Basic authentication" also applies.

Building the winrm go and executable

You can build winrm from source:

git clone https://github.com/masterzen/winrm
cd winrm
make

Note: this winrm code doesn't depend anymore on Gokogiri which means it is now in pure Go.

Note: you need go 1.5+. Please check your installation with

go version

Command-line usage

For command-line usage check the winrm-cli project

Library Usage

Warning the API might be subject to change.

For the fast version (this doesn't allow to send input to the command) and it's using HTTP as the transport:

package main

import (
    "github.com/masterzen/winrm"
    "os"
)

endpoint := winrm.NewEndpoint(host, 5986, false, false, nil, nil, nil, 0)
client, err := winrm.NewClient(endpoint, "Administrator", "secret")
if err != nil {
    panic(err)
}
ctx, cancel := context.WithCancel(context.Background())
defer cancel()
client.RunWithContext(ctx, "ipconfig /all", os.Stdout, os.Stderr)

or

package main
import (
  "github.com/masterzen/winrm"
  "fmt"
  "os"
)

endpoint := winrm.NewEndpoint("localhost", 5985, false, false, nil, nil, nil, 0)
client, err := winrm.NewClient(endpoint,"Administrator", "secret")
if err != nil {
    panic(err)
}

ctx, cancel := context.WithCancel(context.Background())
defer cancel()
_, err := client.RunWithContextWithInput(ctx, "ipconfig", os.Stdout, os.Stderr, os.Stdin)
if err != nil {
    panic(err)
}

By passing a TransportDecorator in the Parameters struct it is possible to use different Transports (e.g. NTLM)

package main
import (
  "github.com/masterzen/winrm"
  "fmt"
  "os"
)

endpoint := winrm.NewEndpoint("localhost", 5985, false, false, nil, nil, nil, 0)

params := DefaultParameters
params.TransportDecorator = func() Transporter { return &ClientNTLM{} }

client, err := NewClientWithParameters(endpoint, "test", "test", params)
if err != nil {
    panic(err)
}

_, err := client.RunWithInput("ipconfig", os.Stdout, os.Stderr, os.Stdin)
if err != nil {
    panic(err)
}

Passing a TransportDecorator also permit to use Kerberos authentication

package main
import (
  "os"
  "fmt"
  "github.com/masterzen/winrm"
)

endpoint := winrm.NewEndpoint("srv-win", 5985, false, false, nil, nil, nil, 0)

params := winrm.DefaultParameters
params.TransportDecorator = func() Transporter {
        return &winrm.ClientKerberos{
        Username: "test",
        Password: "s3cr3t",
        Hostname: "srv-win",
        Realm: "DOMAIN.LAN",
        Port: 5985,
        Proto: "http",
        KrbConf: "/etc/krb5.conf",
        SPN: fmt.Sprintf("HTTP/%s", hostname),
    }
}

client, err := NewClientWithParameters(endpoint, "test", "s3cr3t", params)
if err != nil {
        panic(err)
}

ctx, cancel := context.WithCancel(context.Background())
defer cancel()
_, err := client.RunWithContextWithInput(ctx, "ipconfig", os.Stdout, os.Stderr, os.Stdin)
if err != nil {
        panic(err)
}

By passing a Dial in the Parameters struct it is possible to use different dialer (e.g. tunnel through SSH)

package main

 import (
    "github.com/masterzen/winrm"
    "golang.org/x/crypto/ssh"
    "os"
 )

 func main() {

    sshClient, err := ssh.Dial("tcp","localhost:22", &ssh.ClientConfig{
        User:"ubuntu",
        Auth: []ssh.AuthMethod{ssh.Password("ubuntu")},
        HostKeyCallback: ssh.InsecureIgnoreHostKey(),
    })

    endpoint := winrm.NewEndpoint("other-host", 5985, false, false, nil, nil, nil, 0)

    params := winrm.DefaultParameters
    params.Dial = sshClient.Dial

    client, err := winrm.NewClientWithParameters(endpoint, "test", "test", params)
    if err != nil {
        panic(err)
    }

    ctx, cancel := context.WithCancel(context.Background())
    defer cancel()
    _, err = client.RunWithContextWithInput(ctx, "ipconfig", os.Stdout, os.Stderr, os.Stdin)
    if err != nil {
        panic(err)
    }
 }

For a more complex example, it is possible to call the various functions directly:

package main

import (
  "github.com/masterzen/winrm"
  "fmt"
  "bytes"
  "os"
)

stdin := bytes.NewBufferString("ipconfig /all")
endpoint := winrm.NewEndpoint("localhost", 5985, false, false,nil, nil, nil, 0)
client , err := winrm.NewClient(endpoint, "Administrator", "secret")
if err != nil {
    panic(err)
}
shell, err := client.CreateShell()
if err != nil {
  panic(err)
}
ctx, cancel := context.WithCancel(context.Background())
defer cancel()
var cmd *winrm.Command
cmd, err = shell.ExecuteWithContext(ctx, "cmd.exe")
if err != nil {
  panic(err)
}

go io.Copy(cmd.Stdin, stdin)
go io.Copy(os.Stdout, cmd.Stdout)
go io.Copy(os.Stderr, cmd.Stderr)

cmd.Wait()
shell.Close()

For using HTTPS authentication with x 509 cert without checking the CA

package main

import (
    "github.com/masterzen/winrm"
    "io/ioutil"
    "log"
    "os"
)

func main() {
    clientCert, err := ioutil.ReadFile("/home/example/winrm_client_cert.pem")
    if err != nil {
        log.Fatalf("failed to read client certificate: %q", err)
    }

    clientKey, err := ioutil.ReadFile("/home/example/winrm_client_key.pem")
    if err != nil {
        log.Fatalf("failed to read client key: %q", err)
    }

    winrm.DefaultParameters.TransportDecorator = func() winrm.Transporter {
        // winrm https module
        return &winrm.ClientAuthRequest{}
    }

    endpoint := winrm.NewEndpoint(
        "192.168.100.2", // host to connect to
        5986,            // winrm port
        true,            // use TLS
        true,            // Allow insecure connection
        nil,             // CA certificate
        clientCert,      // Client Certificate
        clientKey,       // Client Key
        0,               // Timeout
    )
    client, err := winrm.NewClient(endpoint, "Administrator", "")
    if err != nil {
        log.Fatalf("failed to create client: %q", err)
    }
    ctx, cancel := context.WithCancel(context.Background())
    defer cancel()
    _, err = client.RunWithContext(ctx, "whoami", os.Stdout, os.Stderr)
    if err != nil {
        log.Fatalf("failed to run command: %q", err)
    }
}

Note: canceling the context.Context passed as first argument to the various functions of the API will not cancel the HTTP requests themselves, it will rather cause a running command to be aborted on the remote machine via a call to command.Stop().

Developing on WinRM

If you wish to work on winrm itself, you'll first need Go installed (version 1.5+ is required). Make sure you have Go properly installed, including setting up your GOPATH.

For some additional dependencies, Go needs Mercurial and Bazaar to be installed. Winrm itself doesn't require these, but a dependency of a dependency does.

Next, clone this repository into $GOPATH/src/github.com/masterzen/winrm and then just type make.

You can run tests by typing make test.

If you make any changes to the code, run make format in order to automatically format the code according to Go standards.

When new dependencies are added to winrm you can use make updatedeps to get the latest and subsequently use make to compile.