refactor SFTP to use the new minio/pkg implementation (#18406)

This commit is contained in:
Sveinn 2023-11-08 17:47:05 +00:00 committed by GitHub
parent 8c9974bc0f
commit 15137d0327
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4 changed files with 175 additions and 199 deletions

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@ -18,20 +18,14 @@
package cmd
import (
"context"
"crypto/subtle"
"fmt"
"net"
"os"
"strconv"
"strings"
"time"
"github.com/minio/cli"
"github.com/minio/minio/internal/logger"
"github.com/pkg/sftp"
ftp "goftp.io/server/v2"
"golang.org/x/crypto/ssh"
)
var globalRemoteFTPClientTransport = NewRemoteTargetHTTPTransport(true)()
@ -75,196 +69,6 @@ func (log *minioLogger) PrintResponse(sessionID string, code int, message string
}
}
func acceptSFTPConnection(conn net.Conn, config *ssh.ServerConfig) {
// For SSH handshake keep a 2 minute deadline, as OpensSSH default.
conn.SetDeadline(time.Now().Add(2 * time.Minute))
// Before use, a handshake must be performed on the incoming net.Conn.
sconn, chans, reqs, err := ssh.NewServerConn(conn, config)
if err != nil {
return
}
// Once we are done with SSH handshake, remove deadline.
conn.SetDeadline(time.Time{})
// 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"
if newChannel.ChannelType() != "session" {
newChannel.Reject(ssh.UnknownChannelType, "unknown channel type")
continue
}
channel, requests, err := newChannel.Accept()
if err != nil {
logger.LogOnceIf(context.Background(), fmt.Errorf("unable to accept the connection requests channel: %w", err), "accept-channel-sftp")
continue
}
// 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 {
ok := false
if req.Type == "subsystem" {
if len(req.Payload) > 4 && string(req.Payload[4:]) == "sftp" {
ok = true
go handleSFTPConnection(channel, sconn)
}
}
if req.WantReply {
// We only reply to SSH packets that have `sftp` payload, all other
// packets are rejected
req.Reply(ok, nil)
}
}
}(requests)
}
}
func handleSFTPConnection(channel ssh.Channel, sconn *ssh.ServerConn) {
// Create the server instance for the channel using the handler we created above.
server := sftp.NewRequestServer(channel, NewSFTPDriver(sconn.Permissions), sftp.WithRSAllocator())
defer server.Close()
server.Serve()
}
func startSFTPServer(c *cli.Context) {
args := c.StringSlice("sftp")
var (
port int
publicIP string
sshPrivateKey string
)
var err error
for _, arg := range args {
tokens := strings.SplitN(arg, "=", 2)
if len(tokens) != 2 {
logger.Fatal(fmt.Errorf("invalid arguments passed to --sftp=%s", arg), "unable to start SFTP server")
}
switch tokens[0] {
case "address":
host, portStr, err := net.SplitHostPort(tokens[1])
if err != nil {
logger.Fatal(fmt.Errorf("invalid arguments passed to --sftp=%s (%v)", arg, err), "unable to start SFTP server")
}
port, err = strconv.Atoi(portStr)
if err != nil {
logger.Fatal(fmt.Errorf("invalid arguments passed to --sftp=%s (%v)", arg, err), "unable to start SFTP server")
}
if port < 1 || port > 65535 {
logger.Fatal(fmt.Errorf("invalid arguments passed to --sftp=%s, (port number must be between 1 to 65535)", arg), "unable to start SFTP server")
}
publicIP = host
case "ssh-private-key":
sshPrivateKey = tokens[1]
}
}
if port == 0 {
port = 8022 // Default SFTP port, since no port was given.
}
if sshPrivateKey == "" {
logger.Fatal(fmt.Errorf("invalid arguments passed, private key file is mandatory for --sftp='ssh-private-key=path/to/id_ecdsa'"), "unable to start SFTP server")
}
privateBytes, err := os.ReadFile(sshPrivateKey)
if err != nil {
logger.Fatal(fmt.Errorf("invalid arguments passed, private key file is not accessible: %v", err), "unable to start SFTP server")
}
private, err := ssh.ParsePrivateKey(privateBytes)
if err != nil {
logger.Fatal(fmt.Errorf("invalid arguments passed, private key file is not parseable: %v", err), "unable to start SFTP server")
}
// 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) {
if globalIAMSys.LDAPConfig.Enabled() {
targetUser, targetGroups, err := globalIAMSys.LDAPConfig.Bind(c.User(), string(pass))
if err != nil {
return nil, err
}
ldapPolicies, _ := globalIAMSys.PolicyDBGet(targetUser, false, targetGroups...)
if len(ldapPolicies) == 0 {
return nil, errAuthentication
}
return &ssh.Permissions{
CriticalOptions: map[string]string{
ldapUser: targetUser,
ldapUserN: c.User(),
},
Extensions: make(map[string]string),
}, nil
}
ui, ok := globalIAMSys.GetUser(context.Background(), c.User())
if !ok {
return nil, errNoSuchUser
}
if subtle.ConstantTimeCompare([]byte(ui.Credentials.SecretKey), pass) == 1 {
return &ssh.Permissions{
CriticalOptions: map[string]string{
"accessKey": c.User(),
},
Extensions: make(map[string]string),
}, nil
}
return nil, errAuthentication
},
}
config.AddHostKey(private)
// Once a ServerConfig has been configured, connections can be accepted.
listener, err := net.Listen("tcp", net.JoinHostPort(publicIP, strconv.Itoa(port)))
if err != nil {
logger.Fatal(err, "unable to start listening on --sftp='port=%d'", port)
}
logger.Info(fmt.Sprintf("MinIO SFTP Server listening on %s", net.JoinHostPort(publicIP, strconv.Itoa(port))))
var tempDelay time.Duration // how long to sleep on accept failure
for {
conn, err := listener.Accept()
if err != nil {
// From https://github.com/golang/go/blob/4aa1efed4853ea067d665a952eee77c52faac774/src/net/http/server.go#L3046
if ne, ok := err.(net.Error); ok && ne.Temporary() {
if tempDelay == 0 {
tempDelay = 5 * time.Millisecond
} else {
tempDelay *= 2
}
if max := 1 * time.Second; tempDelay > max {
tempDelay = max
}
logger.LogOnceIf(context.Background(), fmt.Errorf("error while accepting connections: %w, retrying in %s", err, tempDelay), "accept-limit-sftp")
time.Sleep(tempDelay)
continue
}
logger.Fatal(err, "unrecoverable error while accepting new connections")
}
go acceptSFTPConnection(conn, config)
}
}
func startFTPServer(c *cli.Context) {
args := c.StringSlice("ftp")

172
cmd/sftp-server.go Normal file
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@ -0,0 +1,172 @@
// Copyright (c) 2015-2023 MinIO, Inc.
//
// This file is part of MinIO Object Storage stack
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package cmd
import (
"context"
"crypto/subtle"
"fmt"
"net"
"os"
"strconv"
"strings"
"time"
"github.com/minio/cli"
"github.com/minio/minio/internal/logger"
xsftp "github.com/minio/pkg/v2/sftp"
"github.com/pkg/sftp"
"golang.org/x/crypto/ssh"
)
type sftpLogger struct{}
func (s *sftpLogger) Info(tag xsftp.LogType, msg string) {
logger.Info(msg)
}
func (s *sftpLogger) Error(tag xsftp.LogType, err error) {
switch tag {
case xsftp.AcceptNetworkError:
logger.LogOnceIf(context.Background(), err, "accept-limit-sftp")
case xsftp.AcceptChannelError:
logger.LogOnceIf(context.Background(), err, "accept-channel-sftp")
case xsftp.SSHKeyExchangeError:
logger.LogOnceIf(context.Background(), err, "key-exchange-sftp")
default:
logger.LogOnceIf(context.Background(), err, "unknown-error-sftp")
}
}
func startSFTPServer(c *cli.Context) {
args := c.StringSlice("sftp")
var (
port int
publicIP string
sshPrivateKey string
)
var err error
for _, arg := range args {
tokens := strings.SplitN(arg, "=", 2)
if len(tokens) != 2 {
logger.Fatal(fmt.Errorf("invalid arguments passed to --sftp=%s", arg), "unable to start SFTP server")
}
switch tokens[0] {
case "address":
host, portStr, err := net.SplitHostPort(tokens[1])
if err != nil {
logger.Fatal(fmt.Errorf("invalid arguments passed to --sftp=%s (%v)", arg, err), "unable to start SFTP server")
}
port, err = strconv.Atoi(portStr)
if err != nil {
logger.Fatal(fmt.Errorf("invalid arguments passed to --sftp=%s (%v)", arg, err), "unable to start SFTP server")
}
if port < 1 || port > 65535 {
logger.Fatal(fmt.Errorf("invalid arguments passed to --sftp=%s, (port number must be between 1 to 65535)", arg), "unable to start SFTP server")
}
publicIP = host
case "ssh-private-key":
sshPrivateKey = tokens[1]
}
}
if port == 0 {
port = 8022 // Default SFTP port, since no port was given.
}
if sshPrivateKey == "" {
logger.Fatal(fmt.Errorf("invalid arguments passed, private key file is mandatory for --sftp='ssh-private-key=path/to/id_ecdsa'"), "unable to start SFTP server")
}
privateBytes, err := os.ReadFile(sshPrivateKey)
if err != nil {
logger.Fatal(fmt.Errorf("invalid arguments passed, private key file is not accessible: %v", err), "unable to start SFTP server")
}
private, err := ssh.ParsePrivateKey(privateBytes)
if err != nil {
logger.Fatal(fmt.Errorf("invalid arguments passed, private key file is not parseable: %v", err), "unable to start SFTP server")
}
// An SSH server is represented by a ServerConfig, which holds
// certificate details and handles authentication of ServerConns.
sshConfig := &ssh.ServerConfig{
PasswordCallback: func(c ssh.ConnMetadata, pass []byte) (*ssh.Permissions, error) {
if globalIAMSys.LDAPConfig.Enabled() {
targetUser, targetGroups, err := globalIAMSys.LDAPConfig.Bind(c.User(), string(pass))
if err != nil {
return nil, err
}
ldapPolicies, _ := globalIAMSys.PolicyDBGet(targetUser, false, targetGroups...)
if len(ldapPolicies) == 0 {
return nil, errAuthentication
}
return &ssh.Permissions{
CriticalOptions: map[string]string{
ldapUser: targetUser,
ldapUserN: c.User(),
},
Extensions: make(map[string]string),
}, nil
}
ui, ok := globalIAMSys.GetUser(context.Background(), c.User())
if !ok {
return nil, errNoSuchUser
}
if subtle.ConstantTimeCompare([]byte(ui.Credentials.SecretKey), pass) == 1 {
return &ssh.Permissions{
CriticalOptions: map[string]string{
"accessKey": c.User(),
},
Extensions: make(map[string]string),
}, nil
}
return nil, errAuthentication
},
}
sshConfig.AddHostKey(private)
handleSFTPSession := func(channel ssh.Channel, sconn *ssh.ServerConn) {
server := sftp.NewRequestServer(channel, NewSFTPDriver(sconn.Permissions), sftp.WithRSAllocator())
defer server.Close()
server.Serve()
}
sftpServer, err := xsftp.NewServer(&xsftp.Options{
PublicIP: publicIP,
Port: port,
// OpensSSH default handshake timeout is 2 minutes.
SSHHandshakeDeadline: 2 * time.Minute,
Logger: new(sftpLogger),
SSHConfig: sshConfig,
HandleSFTPSession: handleSFTPSession,
})
if err != nil {
logger.Fatal(err, "Unable to start SFTP Server")
}
err = sftpServer.Listen()
if err != nil {
logger.Fatal(err, "SFTP Server had an unrecoverable error while accepting connections")
}
}

2
go.mod
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@ -51,7 +51,7 @@ require (
github.com/minio/madmin-go/v3 v3.0.29
github.com/minio/minio-go/v7 v7.0.64-0.20230920204636-e783c9ba11b3
github.com/minio/mux v1.9.0
github.com/minio/pkg/v2 v2.0.2
github.com/minio/pkg/v2 v2.0.3-0.20231107172951-8a60b89ec9b4
github.com/minio/selfupdate v0.6.0
github.com/minio/sha256-simd v1.0.1
github.com/minio/simdjson-go v0.4.5

4
go.sum
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@ -491,8 +491,8 @@ github.com/minio/mux v1.9.0 h1:dWafQFyEfGhJvK6AwLOt83bIG5bxKxKJnKMCi0XAaoA=
github.com/minio/mux v1.9.0/go.mod h1:1pAare17ZRL5GpmNL+9YmqHoWnLmMZF9C/ioUCfy0BQ=
github.com/minio/pkg v1.7.5 h1:UOUJjewE5zoaDPlCMJtNx/swc1jT1ZR+IajT7hrLd44=
github.com/minio/pkg v1.7.5/go.mod h1:mEfGMTm5Z0b5EGxKNuPwyb5A2d+CC/VlUyRj6RJtIwo=
github.com/minio/pkg/v2 v2.0.2 h1:cytXmC21fBNS+0NVKEE5FuYmQfY+HFTqis6Kkj3U9ac=
github.com/minio/pkg/v2 v2.0.2/go.mod h1:6xTAr5M9yobpUroXAAaTrGJ9fhOZIqKYOT0I87u2yZ4=
github.com/minio/pkg/v2 v2.0.3-0.20231107172951-8a60b89ec9b4 h1:5eHjHtFZrrCQ3eO0sesXomdAUTtcGh0Fpp7Qa6dtjrY=
github.com/minio/pkg/v2 v2.0.3-0.20231107172951-8a60b89ec9b4/go.mod h1:6xTAr5M9yobpUroXAAaTrGJ9fhOZIqKYOT0I87u2yZ4=
github.com/minio/selfupdate v0.6.0 h1:i76PgT0K5xO9+hjzKcacQtO7+MjJ4JKA8Ak8XQ9DDwU=
github.com/minio/selfupdate v0.6.0/go.mod h1:bO02GTIPCMQFTEvE5h4DjYB58bCoZ35XLeBf0buTDdM=
github.com/minio/sha256-simd v0.1.1/go.mod h1:B5e1o+1/KgNmWrSQK08Y6Z1Vb5pwIktudl0J58iy0KM=