Merge pull request #48 from xor-gate/sftp-beta-for-upstream

Add SftpFs experimental backend

README.md

@@ -263,12 +263,17 @@ backed file implementation. This can be used in other memory backed file
 systems with ease. Plans are to add a radix tree memory stored file
 system using InMemoryFile.
 
+## SftpFs
+
+Afero has experimental support for secure file transfer protocol (sftp). Which can
+be used to perform file operations over a encrypted channel.
+
 ## Desired/possible backends
 
 The following is a short list of possible backends we hope someone will
 implement:
 
-* SSH/SCP
+* SSH
 * ZIP
 * TAR
 * S3
@@ -361,6 +366,7 @@ Names in no particular order:
 * [spf13](https://github.com/spf13)
 * [jaqx0r](https://github.com/jaqx0r)
 * [mbertschler](https://github.com/mbertschler)
+* [xor-gate](https://github.com/xor-gate)
 
 ## License
 

sftp.go

@@ -0,0 +1,128 @@
+// Copyright © 2015 Jerry Jacobs <jerry.jacobs@xor-gate.org>.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package afero
+
+import (
+	"os"
+	"time"
+
+	"github.com/spf13/afero/sftp"
+
+	"github.com/pkg/sftp"
+)
+
+// SftpFs is a Fs implementation that uses functions provided by the sftp package.
+//
+// For details in any method, check the documentation of the sftp package
+// (github.com/pkg/sftp).
+type SftpFs struct{
+	SftpClient  *sftp.Client
+}
+
+func (s SftpFs) Name() string { return "SftpFs" }
+
+func (s SftpFs) Create(name string) (File, error) {
+	f, err := sftpfs.FileCreate(s.SftpClient, name)
+	return f, err
+}
+
+func (s SftpFs) Mkdir(name string, perm os.FileMode) error {
+	err := s.SftpClient.Mkdir(name)
+	if err != nil {
+		return err
+	}
+	return s.SftpClient.Chmod(name, perm)
+}
+
+func (s SftpFs) MkdirAll(path string, perm os.FileMode) error {
+	// Fast path: if we can tell whether path is a directory or file, stop with success or error.
+	dir, err := s.Stat(path)
+	if err == nil {
+		if dir.IsDir() {
+			return nil
+		}
+		return err
+	}
+
+	// Slow path: make sure parent exists and then call Mkdir for path.
+	i := len(path)
+	for i > 0 && os.IsPathSeparator(path[i-1]) { // Skip trailing path separator.
+		i--
+	}
+
+	j := i
+	for j > 0 && !os.IsPathSeparator(path[j-1]) { // Scan backward over element.
+		j--
+	}
+
+	if j > 1 {
+		// Create parent
+		err = s.MkdirAll(path[0:j-1], perm)
+		if err != nil {
+			return err
+		}
+	}
+
+	// Parent now exists; invoke Mkdir and use its result.
+	err = s.Mkdir(path, perm)
+	if err != nil {
+		// Handle arguments like "foo/." by
+		// double-checking that directory doesn't exist.
+		dir, err1 := s.Lstat(path)
+		if err1 == nil && dir.IsDir() {
+			return nil
+		}
+		return err
+	}
+	return nil
+}
+
+func (s SftpFs) Open(name string) (File, error) {
+	f, err := sftpfs.FileOpen(s.SftpClient, name)
+	return f, err
+}
+
+func (s SftpFs) OpenFile(name string, flag int, perm os.FileMode) (File, error) {
+	return nil,nil
+}
+
+func (s SftpFs) Remove(name string) error {
+	return s.SftpClient.Remove(name)
+}
+
+func (s SftpFs) RemoveAll(path string) error {
+	// TODO have a look at os.RemoveAll
+	// https://github.com/golang/go/blob/master/src/os/path.go#L66
+	return nil
+}
+
+func (s SftpFs) Rename(oldname, newname string) error {
+	return s.SftpClient.Rename(oldname, newname)
+}
+
+func (s SftpFs) Stat(name string) (os.FileInfo, error) {
+	return s.SftpClient.Stat(name)
+}
+
+func (s SftpFs) Lstat(p string) (os.FileInfo, error) {
+	return s.SftpClient.Lstat(p)
+}
+
+func (s SftpFs) Chmod(name string, mode os.FileMode) error {
+	return s.SftpClient.Chmod(name, mode)
+}
+
+func (s SftpFs) Chtimes(name string, atime time.Time, mtime time.Time) error {
+	return s.SftpClient.Chtimes(name, atime, mtime)
+}

sftp/file.go

@@ -0,0 +1,95 @@
+// Copyright © 2015 Jerry Jacobs <jerry.jacobs@xor-gate.org>.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package sftpfs
+
+import (
+	"os"
+	"github.com/pkg/sftp"
+)
+
+type File struct {
+	fd *sftp.File
+}
+
+func FileOpen(s *sftp.Client, name string) (*File, error) {
+	fd, err := s.Open(name)
+	if err != nil {
+		return &File{}, err
+	}
+	return &File{fd: fd}, nil
+}
+
+func FileCreate(s *sftp.Client, name string) (*File, error) {
+	fd, err := s.Create(name)
+	if err != nil {
+		return &File{}, err
+	}
+	return &File{fd: fd}, nil
+}
+
+func (f *File) Close() error {
+	return f.fd.Close()
+}
+
+func (f *File) Name() string {
+	return f.fd.Name()
+}
+
+func (f *File) Stat() (os.FileInfo, error) {
+	return f.fd.Stat()
+}
+
+func (f *File) Sync() error {
+	return nil
+}
+
+func (f *File) Truncate(size int64) error {
+	return f.fd.Truncate(size)
+}
+
+func (f *File) Read(b []byte) (n int, err error) {
+	return f.fd.Read(b)
+}
+
+// TODO
+func (f *File) ReadAt(b []byte, off int64) (n int, err error) {
+	return 0,nil
+}
+
+// TODO
+func (f *File) Readdir(count int) (res []os.FileInfo, err error) {
+	return nil,nil
+}
+
+// TODO
+func (f *File) Readdirnames(n int) (names []string, err error) {
+	return nil,nil
+}
+
+func (f *File) Seek(offset int64, whence int) (int64, error) {
+	return f.fd.Seek(offset, whence)
+}
+
+func (f *File) Write(b []byte) (n int, err error) {
+	return f.fd.Write(b)
+}
+
+// TODO
+func (f *File) WriteAt(b []byte, off int64) (n int, err error) {
+	return 0,nil
+}
+
+func (f *File) WriteString(s string) (ret int, err error) {
+	return f.fd.Write([]byte(s))
+}

sftp_test.go

@@ -0,0 +1,286 @@
+// Copyright © 2015 Jerry Jacobs <jerry.jacobs@xor-gate.org>.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package afero
+
+import (
+	"testing"
+	"os"
+	"log"
+	"fmt"
+	"net"
+	"flag"
+	"time"
+	"io/ioutil"
+	"crypto/rsa"
+	_rand "crypto/rand"
+	"encoding/pem"
+	"crypto/x509"
+
+	"golang.org/x/crypto/ssh"
+	"github.com/pkg/sftp"
+)
+
+type SftpFsContext struct {
+	sshc   *ssh.Client
+	sshcfg *ssh.ClientConfig
+	sftpc  *sftp.Client
+}
+
+// TODO we only connect with hardcoded user+pass for now
+// it should be possible to use $HOME/.ssh/id_rsa to login into the stub sftp server
+func SftpConnect(user, password, host string) (*SftpFsContext, error) {
+/*
+	pemBytes, err := ioutil.ReadFile(os.Getenv("HOME") + "/.ssh/id_rsa")
+	if err != nil {
+		return nil,err
+	}
+
+	signer, err := ssh.ParsePrivateKey(pemBytes)
+	if err != nil {
+		return nil,err
+	}
+
+	sshcfg := &ssh.ClientConfig{
+		User: user,
+		Auth: []ssh.AuthMethod{
+			ssh.Password(password),
+			ssh.PublicKeys(signer),
+		},
+	}
+*/
+
+	sshcfg := &ssh.ClientConfig{
+		User: user,
+		Auth: []ssh.AuthMethod{
+			ssh.Password(password),
+		},
+	}
+
+	sshc, err := ssh.Dial("tcp", host, sshcfg)
+	if err != nil {
+		return nil,err
+	}
+
+	sftpc, err := sftp.NewClient(sshc)
+	if err != nil {
+		return nil,err
+	}
+
+	ctx := &SftpFsContext{
+		sshc: sshc,
+		sshcfg: sshcfg,
+		sftpc: sftpc,
+	}
+
+	return ctx,nil
+}
+
+func (ctx *SftpFsContext) Disconnect() error {
+	ctx.sftpc.Close()
+	ctx.sshc.Close()
+	return nil
+}
+
+// TODO for such a weird reason rootpath is "." when writing "file1" with afero sftp backend
+func RunSftpServer(rootpath string) {
+	var (
+		readOnly      bool
+		debugLevelStr string
+		debugLevel    int
+		debugStderr   bool
+		rootDir       string
+	)
+
+	flag.BoolVar(&readOnly, "R", false, "read-only server")
+	flag.BoolVar(&debugStderr, "e", true, "debug to stderr")
+	flag.StringVar(&debugLevelStr, "l", "none", "debug level")
+	flag.StringVar(&rootDir, "root", rootpath, "root directory")
+	flag.Parse()
+
+	debugStream := ioutil.Discard
+	if debugStderr {
+		debugStream = os.Stderr
+		debugLevel = 1
+	}
+
+	// An SSH server is represented by a ServerConfig, which holds
+	// certificate details and handles authentication of ServerConns.
+	config := &ssh.ServerConfig{
+		PasswordCallback: func(c ssh.ConnMetadata, pass []byte) (*ssh.Permissions, error) {
+			// Should use constant-time compare (or better, salt+hash) in
+			// a production setting.
+			fmt.Fprintf(debugStream, "Login: %s\n", c.User())
+			if c.User() == "test" && string(pass) == "test" {
+				return nil, nil
+			}
+			return nil, fmt.Errorf("password rejected for %q", c.User())
+		},
+	}
+
+	privateBytes, err := ioutil.ReadFile("./test/id_rsa")
+	if err != nil {
+		log.Fatal("Failed to load private key", err)
+	}
+
+	private, err := ssh.ParsePrivateKey(privateBytes)
+	if err != nil {
+		log.Fatal("Failed to parse private key", err)
+	}
+
+	config.AddHostKey(private)
+
+	// Once a ServerConfig has been configured, connections can be
+	// accepted.
+	listener, err := net.Listen("tcp", "0.0.0.0:2022")
+	if err != nil {
+		log.Fatal("failed to listen for connection", err)
+	}
+	fmt.Printf("Listening on %v\n", listener.Addr())
+
+	nConn, err := listener.Accept()
+	if err != nil {
+		log.Fatal("failed to accept incoming connection", err)
+	}
+
+	// Before use, a handshake must be performed on the incoming
+	// net.Conn.
+	_, chans, reqs, err := ssh.NewServerConn(nConn, config)
+	if err != nil {
+		log.Fatal("failed to handshake", err)
+	}
+	fmt.Fprintf(debugStream, "SSH server established\n")
+
+	// The incoming Request channel must be serviced.
+	go ssh.DiscardRequests(reqs)
+
+	// Service the incoming Channel channel.
+	for newChannel := range chans {
+		// Channels have a type, depending on the application level
+		// protocol intended. In the case of an SFTP session, this is "subsystem"
+		// with a payload string of "<length=4>sftp"
+		fmt.Fprintf(debugStream, "Incoming channel: %s\n", newChannel.ChannelType())
+		if newChannel.ChannelType() != "session" {
+			newChannel.Reject(ssh.UnknownChannelType, "unknown channel type")
+			fmt.Fprintf(debugStream, "Unknown channel type: %s\n", newChannel.ChannelType())
+			continue
+		}
+		channel, requests, err := newChannel.Accept()
+		if err != nil {
+			log.Fatal("could not accept channel.", err)
+		}
+		fmt.Fprintf(debugStream, "Channel accepted\n")
+
+		// Sessions have out-of-band requests such as "shell",
+		// "pty-req" and "env".  Here we handle only the
+		// "subsystem" request.
+		go func(in <-chan *ssh.Request) {
+			for req := range in {
+				fmt.Fprintf(debugStream, "Request: %v\n", req.Type)
+				ok := false
+				switch req.Type {
+				case "subsystem":
+					fmt.Fprintf(debugStream, "Subsystem: %s\n", req.Payload[4:])
+					if string(req.Payload[4:]) == "sftp" {
+						ok = true
+					}
+				}
+				fmt.Fprintf(debugStream, " - accepted: %v\n", ok)
+				req.Reply(ok, nil)
+			}
+		}(requests)
+
+		server, err := sftp.NewServer(channel, channel, debugStream, debugLevel, readOnly, rootpath)
+		if err != nil {
+			log.Fatal(err)
+		}
+		if err := server.Serve(); err != nil {
+			log.Fatal("sftp server completed with error:", err)
+		}
+	}
+}
+
+// MakeSSHKeyPair make a pair of public and private keys for SSH access.
+// Public key is encoded in the format for inclusion in an OpenSSH authorized_keys file.
+// Private Key generated is PEM encoded
+func MakeSSHKeyPair(bits int, pubKeyPath, privateKeyPath string) error {
+	privateKey, err := rsa.GenerateKey(_rand.Reader, bits)
+	if err != nil {
+		return err
+	}
+
+	// generate and write private key as PEM
+	privateKeyFile, err := os.Create(privateKeyPath)
+	defer privateKeyFile.Close()
+	if err != nil {
+		return err
+	}
+
+	privateKeyPEM := &pem.Block{Type: "RSA PRIVATE KEY", Bytes: x509.MarshalPKCS1PrivateKey(privateKey)}
+	if err := pem.Encode(privateKeyFile, privateKeyPEM); err != nil {
+		return err
+	}
+
+	// generate and write public key
+	pub, err := ssh.NewPublicKey(&privateKey.PublicKey)
+	if err != nil {
+		return err
+	}
+
+	return ioutil.WriteFile(pubKeyPath, ssh.MarshalAuthorizedKey(pub), 0655)
+}
+
+func TestSftpCreate(t *testing.T) {
+	os.Mkdir("./test", 0777)
+	MakeSSHKeyPair(1024, "./test/id_rsa.pub", "./test/id_rsa")
+
+	go RunSftpServer("./test/")
+	time.Sleep(5 * time.Second)
+
+	ctx, err := SftpConnect("test", "test", "localhost:2022")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer ctx.Disconnect()
+
+	var AppFs Fs = SftpFs{
+		SftpClient: ctx.sftpc,
+	}
+
+	AppFs.MkdirAll("test/dir1/dir2/dir3", os.FileMode(0777))
+	AppFs.Mkdir("test/foo", os.FileMode(0000))
+	AppFs.Chmod("test/foo", os.FileMode(0700))
+	AppFs.Mkdir("test/bar", os.FileMode(0777))
+
+	file, err := AppFs.Create("file1")
+	if err != nil {
+		t.Error(err)
+	}
+	defer file.Close()
+
+	file.Write([]byte("hello\t"))
+	file.WriteString("world!\n")
+
+	f1, err := AppFs.Open("file1")
+	if err != nil {
+		log.Fatalf("open: %v", err)
+	}
+	defer f1.Close()
+
+	b := make([]byte, 100)
+
+	_, err = f1.Read(b)
+	fmt.Println(string(b))
+
+	// TODO check here if "hello\tworld\n" is in buffer b
+}