CHORE: Vendor go-powershell (#2837)

pkg/powershell/LICENSE

@@ -0,0 +1,21 @@
+Copyright (c) 2017, Gorillalabs
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+
+http://www.opensource.org/licenses/MIT

pkg/powershell/README.md

@@ -0,0 +1,110 @@
+# go-powershell
+
+This package is inspired by [jPowerShell](https://github.com/profesorfalken/jPowerShell)
+and allows one to run and remote-control a PowerShell session. Use this if you
+don't have a static script that you want to execute, bur rather run dynamic
+commands.
+
+## Installation
+
+    go get github.com/bhendo/go-powershell
+
+## Usage
+
+To start a PowerShell shell, you need a backend. Backends take care of starting
+and controlling the actual powershell.exe process. In most cases, you will want
+to use the Local backend, which just uses ``os/exec`` to start the process.
+
+```go
+package main
+
+import (
+	"fmt"
+
+	ps "github.com/bhendo/go-powershell"
+	"github.com/bhendo/go-powershell/backend"
+)
+
+func main() {
+	// choose a backend
+	back := &backend.Local{}
+
+	// start a local powershell process
+	shell, err := ps.New(back)
+	if err != nil {
+		panic(err)
+	}
+	defer shell.Exit()
+
+	// ... and interact with it
+	stdout, stderr, err := shell.Execute("Get-WmiObject -Class Win32_Processor")
+	if err != nil {
+		panic(err)
+	}
+
+	fmt.Println(stdout)
+}
+```
+
+## Remote Sessions
+
+You can use an existing PS shell to use PSSession cmdlets to connect to remote
+computers. Instead of manually handling that, you can use the Session middleware,
+which takes care of authentication. Note that you can still use the "raw" shell
+to execute commands on the computer where the powershell host process is running.
+
+```go
+package main
+
+import (
+	"fmt"
+
+	ps "github.com/bhendo/go-powershell"
+	"github.com/bhendo/go-powershell/backend"
+	"github.com/bhendo/go-powershell/middleware"
+)
+
+func main() {
+	// choose a backend
+	back := &backend.Local{}
+
+	// start a local powershell process
+	shell, err := ps.New(back)
+	if err != nil {
+		panic(err)
+	}
+
+	// prepare remote session configuration
+	config := middleware.NewSessionConfig()
+	config.ComputerName = "remote-pc-1"
+
+	// create a new shell by wrapping the existing one in the session middleware
+	session, err := middleware.NewSession(shell, config)
+	if err != nil {
+		panic(err)
+	}
+	defer session.Exit() // will also close the underlying ps shell!
+
+	// everything run via the session is run on the remote machine
+	stdout, stderr, err = session.Execute("Get-WmiObject -Class Win32_Processor")
+	if err != nil {
+		panic(err)
+	}
+
+	fmt.Println(stdout)
+}
+```
+
+Note that a single shell instance is not safe for concurrent use, as are remote
+sessions. You can have as many remote sessions using the same shell as you like,
+but you must execute commands serially. If you need concurrency, you can just
+spawn multiple PowerShell processes (i.e. call ``.New()`` multiple times).
+
+Also, note that all commands that you execute are wrapped in special echo
+statements to delimit the stdout/stderr streams. After ``.Execute()``ing a command,
+you can therefore not access ``$LastExitCode`` anymore and expect meaningful
+results.
+
+## License
+
+MIT, see LICENSE file.

pkg/powershell/backend/local.go

@@ -0,0 +1,38 @@
+// Copyright (c) 2017 Gorillalabs. All rights reserved.
+
+package backend
+
+import (
+	"io"
+	"os/exec"
+
+	"github.com/juju/errors"
+)
+
+type Local struct{}
+
+func (b *Local) StartProcess(cmd string, args ...string) (Waiter, io.Writer, io.Reader, io.Reader, error) {
+	command := exec.Command(cmd, args...)
+
+	stdin, err := command.StdinPipe()
+	if err != nil {
+		return nil, nil, nil, nil, errors.Annotate(err, "Could not get hold of the PowerShell's stdin stream")
+	}
+
+	stdout, err := command.StdoutPipe()
+	if err != nil {
+		return nil, nil, nil, nil, errors.Annotate(err, "Could not get hold of the PowerShell's stdout stream")
+	}
+
+	stderr, err := command.StderrPipe()
+	if err != nil {
+		return nil, nil, nil, nil, errors.Annotate(err, "Could not get hold of the PowerShell's stderr stream")
+	}
+
+	err = command.Start()
+	if err != nil {
+		return nil, nil, nil, nil, errors.Annotate(err, "Could not spawn PowerShell process")
+	}
+
+	return command, stdin, stdout, stderr, nil
+}

pkg/powershell/backend/ssh.go

@@ -0,0 +1,69 @@
+// Copyright (c) 2017 Gorillalabs. All rights reserved.
+
+package backend
+
+import (
+	"fmt"
+	"io"
+	"regexp"
+	"strings"
+
+	"github.com/juju/errors"
+)
+
+// sshSession exists so we don't create a hard dependency on crypto/ssh.
+type sshSession interface {
+	Waiter
+
+	StdinPipe() (io.WriteCloser, error)
+	StdoutPipe() (io.Reader, error)
+	StderrPipe() (io.Reader, error)
+	Start(string) error
+}
+
+type SSH struct {
+	Session sshSession
+}
+
+func (b *SSH) StartProcess(cmd string, args ...string) (Waiter, io.Writer, io.Reader, io.Reader, error) {
+	stdin, err := b.Session.StdinPipe()
+	if err != nil {
+		return nil, nil, nil, nil, errors.Annotate(err, "Could not get hold of the SSH session's stdin stream")
+	}
+
+	stdout, err := b.Session.StdoutPipe()
+	if err != nil {
+		return nil, nil, nil, nil, errors.Annotate(err, "Could not get hold of the SSH session's stdout stream")
+	}
+
+	stderr, err := b.Session.StderrPipe()
+	if err != nil {
+		return nil, nil, nil, nil, errors.Annotate(err, "Could not get hold of the SSH session's stderr stream")
+	}
+
+	err = b.Session.Start(b.createCmd(cmd, args))
+	if err != nil {
+		return nil, nil, nil, nil, errors.Annotate(err, "Could not spawn process via SSH")
+	}
+
+	return b.Session, stdin, stdout, stderr, nil
+}
+
+func (b *SSH) createCmd(cmd string, args []string) string {
+	parts := []string{cmd}
+	simple := regexp.MustCompile(`^[a-z0-9_/.~+-]+$`)
+
+	for _, arg := range args {
+		if !simple.MatchString(arg) {
+			arg = b.quote(arg)
+		}
+
+		parts = append(parts, arg)
+	}
+
+	return strings.Join(parts, " ")
+}
+
+func (b *SSH) quote(s string) string {
+	return fmt.Sprintf(`"%s"`, s)
+}

pkg/powershell/backend/types.go

@@ -0,0 +1,13 @@
+// Copyright (c) 2017 Gorillalabs. All rights reserved.
+
+package backend
+
+import "io"
+
+type Waiter interface {
+	Wait() error
+}
+
+type Starter interface {
+	StartProcess(cmd string, args ...string) (Waiter, io.Writer, io.Reader, io.Reader, error)
+}

pkg/powershell/middleware/session.go

@@ -0,0 +1,47 @@
+// Copyright (c) 2017 Gorillalabs. All rights reserved.
+
+package middleware
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/StackExchange/dnscontrol/v4/pkg/powershell/utils"
+	"github.com/juju/errors"
+)
+
+type session struct {
+	upstream Middleware
+	name     string
+}
+
+func NewSession(upstream Middleware, config *SessionConfig) (Middleware, error) {
+	asserted, ok := config.Credential.(credential)
+	if ok {
+		credentialParamValue, err := asserted.prepare(upstream)
+		if err != nil {
+			return nil, errors.Annotate(err, "Could not setup credentials")
+		}
+
+		config.Credential = credentialParamValue
+	}
+
+	name := "goSess" + utils.CreateRandomString(8)
+	args := strings.Join(config.ToArgs(), " ")
+
+	_, _, err := upstream.Execute(fmt.Sprintf("$%s = New-PSSession %s", name, args))
+	if err != nil {
+		return nil, errors.Annotate(err, "Could not create new PSSession")
+	}
+
+	return &session{upstream, name}, nil
+}
+
+func (s *session) Execute(cmd string) (string, string, error) {
+	return s.upstream.Execute(fmt.Sprintf("Invoke-Command -Session $%s -Script {%s}", s.name, cmd))
+}
+
+func (s *session) Exit() {
+	s.upstream.Execute(fmt.Sprintf("Disconnect-PSSession -Session $%s", s.name))
+	s.upstream.Exit()
+}

pkg/powershell/middleware/session_config.go

@@ -0,0 +1,95 @@
+// Copyright (c) 2017 Gorillalabs. All rights reserved.
+
+package middleware
+
+import (
+	"fmt"
+	"strconv"
+
+	"github.com/StackExchange/dnscontrol/v4/pkg/powershell/utils"
+	"github.com/juju/errors"
+)
+
+const (
+	HTTPPort  = 5985
+	HTTPSPort = 5986
+)
+
+type SessionConfig struct {
+	ComputerName          string
+	AllowRedirection      bool
+	Authentication        string
+	CertificateThumbprint string
+	Credential            interface{}
+	Port                  int
+	UseSSL                bool
+}
+
+func NewSessionConfig() *SessionConfig {
+	return &SessionConfig{}
+}
+
+func (c *SessionConfig) ToArgs() []string {
+	args := make([]string, 0)
+
+	if c.ComputerName != "" {
+		args = append(args, "-ComputerName")
+		args = append(args, utils.QuoteArg(c.ComputerName))
+	}
+
+	if c.AllowRedirection {
+		args = append(args, "-AllowRedirection")
+	}
+
+	if c.Authentication != "" {
+		args = append(args, "-Authentication")
+		args = append(args, utils.QuoteArg(c.Authentication))
+	}
+
+	if c.CertificateThumbprint != "" {
+		args = append(args, "-CertificateThumbprint")
+		args = append(args, utils.QuoteArg(c.CertificateThumbprint))
+	}
+
+	if c.Port > 0 {
+		args = append(args, "-Port")
+		args = append(args, strconv.Itoa(c.Port))
+	}
+
+	if asserted, ok := c.Credential.(string); ok {
+		args = append(args, "-Credential")
+		args = append(args, asserted) // do not quote, as it contains a variable name when using password auth
+	}
+
+	if c.UseSSL {
+		args = append(args, "-UseSSL")
+	}
+
+	return args
+}
+
+type credential interface {
+	prepare(Middleware) (interface{}, error)
+}
+
+type UserPasswordCredential struct {
+	Username string
+	Password string
+}
+
+func (c *UserPasswordCredential) prepare(s Middleware) (interface{}, error) {
+	name := "goCred" + utils.CreateRandomString(8)
+	pwname := "goPass" + utils.CreateRandomString(8)
+
+	_, _, err := s.Execute(fmt.Sprintf("$%s = ConvertTo-SecureString -String %s -AsPlainText -Force", pwname, utils.QuoteArg(c.Password)))
+	if err != nil {
+		return nil, errors.Annotate(err, "Could not convert password to secure string")
+	}
+
+	_, _, err = s.Execute(fmt.Sprintf("$%s = New-Object -TypeName 'System.Management.Automation.PSCredential' -ArgumentList %s, $%s", name, utils.QuoteArg(c.Username), pwname))
+	if err != nil {
+		return nil, errors.Annotate(err, "Could not create PSCredential object")
+	}
+
+	return fmt.Sprintf("$%s", name), nil
+}

pkg/powershell/middleware/types.go

@@ -0,0 +1,8 @@
+// Copyright (c) 2017 Gorillalabs. All rights reserved.
+
+package middleware
+
+type Middleware interface {
+	Execute(cmd string) (string, string, error)
+	Exit()
+}

pkg/powershell/middleware/utf8.go

@@ -0,0 +1,49 @@
+// Copyright (c) 2017 Gorillalabs. All rights reserved.
+
+package middleware
+
+import (
+	"encoding/base64"
+	"fmt"
+
+	"github.com/StackExchange/dnscontrol/v4/pkg/powershell/utils"
+)
+
+// utf8 implements a primitive middleware that encodes all outputs
+// as base64 to prevent encoding issues between remote PowerShell
+// shells and the receiver. Just setting $OutputEncoding does not
+// work reliably enough, sadly.
+type utf8 struct {
+	upstream Middleware
+	wrapper  string
+}
+
+func NewUTF8(upstream Middleware) (Middleware, error) {
+	wrapper := "goUTF8" + utils.CreateRandomString(8)
+
+	_, _, err := upstream.Execute(fmt.Sprintf(`function %s { process { if ($_) { [Convert]::ToBase64String([Text.Encoding]::UTF8.GetBytes($_)) } else { '' } } }`, wrapper))
+
+	return &utf8{upstream, wrapper}, err
+}
+
+func (u *utf8) Execute(cmd string) (string, string, error) {
+	// Out-String to concat all lines into a single line,
+	// Write-Host to prevent line breaks at the "window width"
+	cmd = fmt.Sprintf(`%s | Out-String | %s | Write-Host`, cmd, u.wrapper)
+
+	stdout, stderr, err := u.upstream.Execute(cmd)
+	if err != nil {
+		return stdout, stderr, err
+	}
+
+	decoded, err := base64.StdEncoding.DecodeString(stdout)
+	if err != nil {
+		return stdout, stderr, err
+	}
+
+	return string(decoded), stderr, nil
+}
+
+func (u *utf8) Exit() {
+	u.upstream.Exit()
+}

pkg/powershell/shell.go

@@ -0,0 +1,120 @@
+// Copyright (c) 2017 Gorillalabs. All rights reserved.
+
+package powershell
+
+import (
+	"fmt"
+	"io"
+	"strings"
+	"sync"
+
+	"github.com/StackExchange/dnscontrol/v4/pkg/powershell/backend"
+	"github.com/StackExchange/dnscontrol/v4/pkg/powershell/utils"
+	"github.com/juju/errors"
+)
+
+const newline = "\r\n"
+
+type Shell interface {
+	Execute(cmd string) (string, string, error)
+	Exit()
+}
+
+type shell struct {
+	handle backend.Waiter
+	stdin  io.Writer
+	stdout io.Reader
+	stderr io.Reader
+}
+
+func New(backend backend.Starter) (Shell, error) {
+	handle, stdin, stdout, stderr, err := backend.StartProcess("powershell.exe", "-NoExit", "-Command", "-")
+	if err != nil {
+		return nil, err
+	}
+
+	return &shell{handle, stdin, stdout, stderr}, nil
+}
+
+func (s *shell) Execute(cmd string) (string, string, error) {
+	if s.handle == nil {
+		return "", "", errors.Annotate(errors.New(cmd), "Cannot execute commands on closed shells.")
+	}
+
+	outBoundary := createBoundary()
+	errBoundary := createBoundary()
+
+	// wrap the command in special markers so we know when to stop reading from the pipes
+	full := fmt.Sprintf("%s; echo '%s'; [Console]::Error.WriteLine('%s')%s", cmd, outBoundary, errBoundary, newline)
+
+	_, err := s.stdin.Write([]byte(full))
+	if err != nil {
+		return "", "", errors.Annotate(errors.Annotate(err, cmd), "Could not send PowerShell command")
+	}
+
+	// read stdout and stderr
+	sout := ""
+	serr := ""
+
+	waiter := &sync.WaitGroup{}
+	waiter.Add(2)
+
+	go streamReader(s.stdout, outBoundary, &sout, waiter)
+	go streamReader(s.stderr, errBoundary, &serr, waiter)
+
+	waiter.Wait()
+
+	if len(serr) > 0 {
+		return sout, serr, errors.Annotate(errors.New(cmd), serr)
+	}
+
+	return sout, serr, nil
+}
+
+func (s *shell) Exit() {
+	s.stdin.Write([]byte("exit" + newline))
+
+	// if it's possible to close stdin, do so (some backends, like the local one,
+	// do support it)
+	closer, ok := s.stdin.(io.Closer)
+	if ok {
+		closer.Close()
+	}
+
+	s.handle.Wait()
+
+	s.handle = nil
+	s.stdin = nil
+	s.stdout = nil
+	s.stderr = nil
+}
+
+func streamReader(stream io.Reader, boundary string, buffer *string, signal *sync.WaitGroup) error {
+	// read all output until we have found our boundary token
+	output := ""
+	bufsize := 64
+	marker := boundary + newline
+
+	for {
+		buf := make([]byte, bufsize)
+		read, err := stream.Read(buf)
+		if err != nil {
+			return err
+		}
+
+		output = output + string(buf[:read])
+
+		if strings.HasSuffix(output, marker) {
+			break
+		}
+	}
+
+	*buffer = strings.TrimSuffix(output, marker)
+	signal.Done()
+
+	return nil
+}
+
+func createBoundary() string {
+	return "$gorilla" + utils.CreateRandomString(12) + "$"
+}

pkg/powershell/utils/quote.go

@@ -0,0 +1,9 @@
+// Copyright (c) 2017 Gorillalabs. All rights reserved.
+
+package utils
+
+import "strings"
+
+func QuoteArg(s string) string {
+	return "'" + strings.Replace(s, "'", "\"", -1) + "'"
+}

pkg/powershell/utils/quote_test.go

@@ -0,0 +1,28 @@
+// Copyright (c) 2017 Gorillalabs. All rights reserved.
+
+package utils
+
+import "testing"
+
+func TestQuotingArguments(t *testing.T) {
+	testcases := [][]string{
+		{"", "''"},
+		{"test", "'test'"},
+		{"two words", "'two words'"},
+		{"quo\"ted", "'quo\"ted'"},
+		{"quo'ted", "'quo\"ted'"},
+		{"quo\\'ted", "'quo\\\"ted'"},
+		{"quo\"t'ed", "'quo\"t\"ed'"},
+		{"es\\caped", "'es\\caped'"},
+		{"es`caped", "'es`caped'"},
+		{"es\\`caped", "'es\\`caped'"},
+	}
+
+	for i, testcase := range testcases {
+		quoted := QuoteArg(testcase[0])
+
+		if quoted != testcase[1] {
+			t.Errorf("test %02d failed: input '%s', expected %s, actual %s", i+1, testcase[0], testcase[1], quoted)
+		}
+	}
+}

pkg/powershell/utils/rand.go

@@ -0,0 +1,20 @@
+// Copyright (c) 2017 Gorillalabs. All rights reserved.
+
+package utils
+
+import (
+	"crypto/rand"
+	"encoding/hex"
+)
+
+func CreateRandomString(bytes int) string {
+	c := bytes
+	b := make([]byte, c)
+
+	_, err := rand.Read(b)
+	if err != nil {
+		panic(err)
+	}
+
+	return hex.EncodeToString(b)
+}

pkg/powershell/utils/rand_test.go

@@ -0,0 +1,16 @@
+// Copyright (c) 2017 Gorillalabs. All rights reserved.
+
+package utils
+
+import "testing"
+
+func TestRandomStrings(t *testing.T) {
+	r1 := CreateRandomString(8)
+	r2 := CreateRandomString(8)
+
+	if r1 == r2 {
+		t.Error("Failed to create random strings: The two generated strings are identical.")
+	} else if len(r1) != 16 {
+		t.Errorf("Expected the random string to contain 16 characters, but got %d.", len(r1))
+	}
+}