437 lines
13 KiB
Go
437 lines
13 KiB
Go
package sftpd
|
|
|
|
import (
|
|
"crypto/md5"
|
|
"crypto/sha1"
|
|
"crypto/sha256"
|
|
"crypto/sha512"
|
|
"errors"
|
|
"fmt"
|
|
"hash"
|
|
"io"
|
|
"os"
|
|
"os/exec"
|
|
"path"
|
|
"path/filepath"
|
|
"strings"
|
|
"sync"
|
|
"time"
|
|
|
|
"github.com/drakkan/sftpgo/dataprovider"
|
|
"github.com/drakkan/sftpgo/logger"
|
|
"github.com/drakkan/sftpgo/metrics"
|
|
"github.com/drakkan/sftpgo/utils"
|
|
"github.com/drakkan/sftpgo/vfs"
|
|
"golang.org/x/crypto/ssh"
|
|
)
|
|
|
|
var (
|
|
errQuotaExceeded = errors.New("denying write due to space limit")
|
|
errPermissionDenied = errors.New("Permission denied. You don't have the permissions to execute this command")
|
|
errUnsupportedConfig = errors.New("command unsupported for this configuration")
|
|
)
|
|
|
|
type sshCommand struct {
|
|
command string
|
|
args []string
|
|
connection Connection
|
|
}
|
|
|
|
type systemCommand struct {
|
|
cmd *exec.Cmd
|
|
realPath string
|
|
}
|
|
|
|
func processSSHCommand(payload []byte, connection *Connection, channel ssh.Channel, enabledSSHCommands []string) bool {
|
|
var msg sshSubsystemExecMsg
|
|
if err := ssh.Unmarshal(payload, &msg); err == nil {
|
|
name, args, err := parseCommandPayload(strings.TrimSpace(msg.Command))
|
|
connection.Log(logger.LevelDebug, logSenderSSH, "new ssh command: %#v args: %v user: %v, error: %v",
|
|
name, args, connection.User.Username, err)
|
|
if err == nil && utils.IsStringInSlice(name, enabledSSHCommands) {
|
|
connection.command = fmt.Sprintf("%v %v", name, strings.Join(args, " "))
|
|
if name == "scp" && len(args) >= 2 {
|
|
connection.protocol = protocolSCP
|
|
connection.channel = channel
|
|
scpCommand := scpCommand{
|
|
sshCommand: sshCommand{
|
|
command: name,
|
|
connection: *connection,
|
|
args: args},
|
|
}
|
|
go scpCommand.handle()
|
|
return true
|
|
}
|
|
if name != "scp" {
|
|
connection.protocol = protocolSSH
|
|
connection.channel = channel
|
|
sshCommand := sshCommand{
|
|
command: name,
|
|
connection: *connection,
|
|
args: args,
|
|
}
|
|
go sshCommand.handle()
|
|
return true
|
|
}
|
|
} else {
|
|
connection.Log(logger.LevelInfo, logSenderSSH, "ssh command not enabled/supported: %#v", name)
|
|
}
|
|
}
|
|
return false
|
|
}
|
|
|
|
func (c *sshCommand) handle() error {
|
|
addConnection(c.connection)
|
|
defer removeConnection(c.connection)
|
|
updateConnectionActivity(c.connection.ID)
|
|
if utils.IsStringInSlice(c.command, sshHashCommands) {
|
|
return c.handleHashCommands()
|
|
} else if utils.IsStringInSlice(c.command, systemCommands) {
|
|
command, err := c.getSystemCommand()
|
|
if err != nil {
|
|
return c.sendErrorResponse(err)
|
|
}
|
|
return c.executeSystemCommand(command)
|
|
} else if c.command == "cd" {
|
|
c.sendExitStatus(nil)
|
|
} else if c.command == "pwd" {
|
|
// hard coded response to "/"
|
|
c.connection.channel.Write([]byte("/\n"))
|
|
c.sendExitStatus(nil)
|
|
}
|
|
return nil
|
|
}
|
|
|
|
func (c *sshCommand) handleHashCommands() error {
|
|
if !vfs.IsLocalOsFs(c.connection.fs) {
|
|
return c.sendErrorResponse(errUnsupportedConfig)
|
|
}
|
|
var h hash.Hash
|
|
if c.command == "md5sum" {
|
|
h = md5.New()
|
|
} else if c.command == "sha1sum" {
|
|
h = sha1.New()
|
|
} else if c.command == "sha256sum" {
|
|
h = sha256.New()
|
|
} else if c.command == "sha384sum" {
|
|
h = sha512.New384()
|
|
} else {
|
|
h = sha512.New()
|
|
}
|
|
var response string
|
|
if len(c.args) == 0 {
|
|
// without args we need to read the string to hash from stdin
|
|
buf := make([]byte, 4096)
|
|
n, err := c.connection.channel.Read(buf)
|
|
if err != nil && err != io.EOF {
|
|
return c.sendErrorResponse(err)
|
|
}
|
|
h.Write(buf[:n])
|
|
response = fmt.Sprintf("%x -\n", h.Sum(nil))
|
|
} else {
|
|
sshPath := c.getDestPath()
|
|
fsPath, err := c.connection.fs.ResolvePath(sshPath)
|
|
if err != nil {
|
|
return c.sendErrorResponse(err)
|
|
}
|
|
if !c.connection.User.HasPerm(dataprovider.PermListItems, sshPath) {
|
|
return c.sendErrorResponse(errPermissionDenied)
|
|
}
|
|
hash, err := computeHashForFile(h, fsPath)
|
|
if err != nil {
|
|
return c.sendErrorResponse(err)
|
|
}
|
|
response = fmt.Sprintf("%v %v\n", hash, sshPath)
|
|
}
|
|
c.connection.channel.Write([]byte(response))
|
|
c.sendExitStatus(nil)
|
|
return nil
|
|
}
|
|
|
|
func (c *sshCommand) executeSystemCommand(command systemCommand) error {
|
|
if !vfs.IsLocalOsFs(c.connection.fs) {
|
|
return c.sendErrorResponse(errUnsupportedConfig)
|
|
}
|
|
if c.connection.User.QuotaFiles > 0 && c.connection.User.UsedQuotaFiles > c.connection.User.QuotaFiles {
|
|
return c.sendErrorResponse(errQuotaExceeded)
|
|
}
|
|
perms := []string{dataprovider.PermDownload, dataprovider.PermUpload, dataprovider.PermCreateDirs, dataprovider.PermListItems,
|
|
dataprovider.PermOverwrite, dataprovider.PermDelete, dataprovider.PermRename}
|
|
if !c.connection.User.HasPerms(perms, c.getDestPath()) {
|
|
return c.sendErrorResponse(errPermissionDenied)
|
|
}
|
|
|
|
stdin, err := command.cmd.StdinPipe()
|
|
if err != nil {
|
|
return c.sendErrorResponse(err)
|
|
}
|
|
stdout, err := command.cmd.StdoutPipe()
|
|
if err != nil {
|
|
return c.sendErrorResponse(err)
|
|
}
|
|
stderr, err := command.cmd.StderrPipe()
|
|
if err != nil {
|
|
return c.sendErrorResponse(err)
|
|
}
|
|
err = command.cmd.Start()
|
|
if err != nil {
|
|
return c.sendErrorResponse(err)
|
|
}
|
|
|
|
closeCmdOnError := func() {
|
|
c.connection.Log(logger.LevelDebug, logSenderSSH, "kill cmd: %#v and close ssh channel after read or write error",
|
|
c.connection.command)
|
|
command.cmd.Process.Kill()
|
|
c.connection.channel.Close()
|
|
}
|
|
var once sync.Once
|
|
commandResponse := make(chan bool)
|
|
|
|
go func() {
|
|
defer stdin.Close()
|
|
remainingQuotaSize := int64(0)
|
|
if c.connection.User.QuotaSize > 0 {
|
|
remainingQuotaSize = c.connection.User.QuotaSize - c.connection.User.UsedQuotaSize
|
|
}
|
|
transfer := Transfer{
|
|
file: nil,
|
|
path: command.realPath,
|
|
start: time.Now(),
|
|
bytesSent: 0,
|
|
bytesReceived: 0,
|
|
user: c.connection.User,
|
|
connectionID: c.connection.ID,
|
|
transferType: transferUpload,
|
|
lastActivity: time.Now(),
|
|
isNewFile: false,
|
|
protocol: c.connection.protocol,
|
|
transferError: nil,
|
|
isFinished: false,
|
|
minWriteOffset: 0,
|
|
lock: new(sync.Mutex),
|
|
}
|
|
addTransfer(&transfer)
|
|
defer removeTransfer(&transfer)
|
|
w, e := transfer.copyFromReaderToWriter(stdin, c.connection.channel, remainingQuotaSize)
|
|
c.connection.Log(logger.LevelDebug, logSenderSSH, "command: %#v, copy from remote command to sdtin ended, written: %v, "+
|
|
"initial remaining quota: %v, err: %v", c.connection.command, w, remainingQuotaSize, e)
|
|
if e != nil {
|
|
once.Do(closeCmdOnError)
|
|
}
|
|
}()
|
|
|
|
go func() {
|
|
transfer := Transfer{
|
|
file: nil,
|
|
path: command.realPath,
|
|
start: time.Now(),
|
|
bytesSent: 0,
|
|
bytesReceived: 0,
|
|
user: c.connection.User,
|
|
connectionID: c.connection.ID,
|
|
transferType: transferDownload,
|
|
lastActivity: time.Now(),
|
|
isNewFile: false,
|
|
protocol: c.connection.protocol,
|
|
transferError: nil,
|
|
isFinished: false,
|
|
minWriteOffset: 0,
|
|
lock: new(sync.Mutex),
|
|
}
|
|
addTransfer(&transfer)
|
|
defer removeTransfer(&transfer)
|
|
w, e := transfer.copyFromReaderToWriter(c.connection.channel, stdout, 0)
|
|
c.connection.Log(logger.LevelDebug, logSenderSSH, "command: %#v, copy from sdtout to remote command ended, written: %v err: %v",
|
|
c.connection.command, w, e)
|
|
if e != nil {
|
|
once.Do(closeCmdOnError)
|
|
}
|
|
commandResponse <- true
|
|
}()
|
|
|
|
go func() {
|
|
transfer := Transfer{
|
|
file: nil,
|
|
path: command.realPath,
|
|
start: time.Now(),
|
|
bytesSent: 0,
|
|
bytesReceived: 0,
|
|
user: c.connection.User,
|
|
connectionID: c.connection.ID,
|
|
transferType: transferDownload,
|
|
lastActivity: time.Now(),
|
|
isNewFile: false,
|
|
protocol: c.connection.protocol,
|
|
transferError: nil,
|
|
isFinished: false,
|
|
minWriteOffset: 0,
|
|
lock: new(sync.Mutex),
|
|
}
|
|
addTransfer(&transfer)
|
|
defer removeTransfer(&transfer)
|
|
w, e := transfer.copyFromReaderToWriter(c.connection.channel.Stderr(), stderr, 0)
|
|
c.connection.Log(logger.LevelDebug, logSenderSSH, "command: %#v, copy from sdterr to remote command ended, written: %v err: %v",
|
|
c.connection.command, w, e)
|
|
// os.ErrClosed means that the command is finished so we don't need to do anything
|
|
if (e != nil && !errors.Is(e, os.ErrClosed)) || w > 0 {
|
|
once.Do(closeCmdOnError)
|
|
}
|
|
}()
|
|
|
|
<-commandResponse
|
|
err = command.cmd.Wait()
|
|
c.sendExitStatus(err)
|
|
c.rescanHomeDir()
|
|
return err
|
|
}
|
|
|
|
func (c *sshCommand) getSystemCommand() (systemCommand, error) {
|
|
command := systemCommand{
|
|
cmd: nil,
|
|
realPath: "",
|
|
}
|
|
args := make([]string, len(c.args))
|
|
copy(args, c.args)
|
|
var path string
|
|
if len(c.args) > 0 {
|
|
var err error
|
|
sshPath := c.getDestPath()
|
|
path, err = c.connection.fs.ResolvePath(sshPath)
|
|
if err != nil {
|
|
return command, err
|
|
}
|
|
args = args[:len(args)-1]
|
|
args = append(args, path)
|
|
}
|
|
if c.command == "rsync" {
|
|
// we cannot avoid that rsync create symlinks so if the user has the permission
|
|
// to create symlinks we add the option --safe-links to the received rsync command if
|
|
// it is not already set. This should prevent to create symlinks that point outside
|
|
// the home dir.
|
|
// If the user cannot create symlinks we add the option --munge-links, if it is not
|
|
// already set. This should make symlinks unusable (but manually recoverable)
|
|
if c.connection.User.HasPerm(dataprovider.PermCreateSymlinks, c.getDestPath()) {
|
|
if !utils.IsStringInSlice("--safe-links", args) {
|
|
args = append([]string{"--safe-links"}, args...)
|
|
}
|
|
} else {
|
|
if !utils.IsStringInSlice("--munge-links", args) {
|
|
args = append([]string{"--munge-links"}, args...)
|
|
}
|
|
}
|
|
}
|
|
c.connection.Log(logger.LevelDebug, logSenderSSH, "new system command %#v, with args: %v path: %v", c.command, args, path)
|
|
cmd := exec.Command(c.command, args...)
|
|
uid := c.connection.User.GetUID()
|
|
gid := c.connection.User.GetGID()
|
|
cmd = wrapCmd(cmd, uid, gid)
|
|
command.cmd = cmd
|
|
command.realPath = path
|
|
return command, nil
|
|
}
|
|
|
|
func (c *sshCommand) rescanHomeDir() error {
|
|
quotaTracking := dataprovider.GetQuotaTracking()
|
|
if (!c.connection.User.HasQuotaRestrictions() && quotaTracking == 2) || quotaTracking == 0 {
|
|
return nil
|
|
}
|
|
var err error
|
|
var numFiles int
|
|
var size int64
|
|
if AddQuotaScan(c.connection.User.Username) {
|
|
numFiles, size, err = c.connection.fs.ScanRootDirContents()
|
|
if err != nil {
|
|
c.connection.Log(logger.LevelWarn, logSenderSSH, "error scanning user home dir %#v: %v", c.connection.User.HomeDir, err)
|
|
} else {
|
|
err := dataprovider.UpdateUserQuota(dataProvider, c.connection.User, numFiles, size, true)
|
|
c.connection.Log(logger.LevelDebug, logSenderSSH, "user home dir scanned, user: %#v, dir: %#v, error: %v",
|
|
c.connection.User.Username, c.connection.User.HomeDir, err)
|
|
}
|
|
RemoveQuotaScan(c.connection.User.Username)
|
|
}
|
|
return err
|
|
}
|
|
|
|
// for the supported command, the path, if any, is the last argument
|
|
func (c *sshCommand) getDestPath() string {
|
|
if len(c.args) == 0 {
|
|
return ""
|
|
}
|
|
destPath := strings.Trim(c.args[len(c.args)-1], "'")
|
|
destPath = strings.Trim(destPath, "\"")
|
|
destPath = filepath.ToSlash(destPath)
|
|
if !path.IsAbs(destPath) {
|
|
destPath = "/" + destPath
|
|
}
|
|
result := path.Clean(destPath)
|
|
if strings.HasSuffix(destPath, "/") && !strings.HasSuffix(result, "/") {
|
|
result += "/"
|
|
}
|
|
return result
|
|
}
|
|
|
|
func (c *sshCommand) sendErrorResponse(err error) error {
|
|
errorString := fmt.Sprintf("%v: %v %v\n", c.command, c.getDestPath(), err)
|
|
c.connection.channel.Write([]byte(errorString))
|
|
c.sendExitStatus(err)
|
|
return err
|
|
}
|
|
|
|
func (c *sshCommand) sendExitStatus(err error) {
|
|
status := uint32(0)
|
|
if err != nil {
|
|
status = uint32(1)
|
|
c.connection.Log(logger.LevelWarn, logSenderSSH, "command failed: %#v args: %v user: %v err: %v",
|
|
c.command, c.args, c.connection.User.Username, err)
|
|
} else {
|
|
logger.CommandLog(sshCommandLogSender, c.getDestPath(), "", c.connection.User.Username, "", c.connection.ID,
|
|
protocolSSH, -1, -1, "", "", c.connection.command)
|
|
}
|
|
exitStatus := sshSubsystemExitStatus{
|
|
Status: status,
|
|
}
|
|
c.connection.channel.SendRequest("exit-status", false, ssh.Marshal(&exitStatus))
|
|
c.connection.channel.Close()
|
|
metrics.SSHCommandCompleted(err)
|
|
// for scp we notify single uploads/downloads
|
|
if err == nil && c.command != "scp" {
|
|
realPath := c.getDestPath()
|
|
if len(realPath) > 0 {
|
|
p, err := c.connection.fs.ResolvePath(realPath)
|
|
if err == nil {
|
|
realPath = p
|
|
}
|
|
}
|
|
go executeAction(operationSSHCmd, c.connection.User.Username, realPath, "", c.command, 0, vfs.IsLocalOsFs(c.connection.fs))
|
|
}
|
|
}
|
|
|
|
func computeHashForFile(hasher hash.Hash, path string) (string, error) {
|
|
hash := ""
|
|
f, err := os.Open(path)
|
|
if err != nil {
|
|
return hash, err
|
|
}
|
|
defer f.Close()
|
|
_, err = io.Copy(hasher, f)
|
|
if err == nil {
|
|
hash = fmt.Sprintf("%x", hasher.Sum(nil))
|
|
}
|
|
return hash, err
|
|
}
|
|
|
|
func parseCommandPayload(command string) (string, []string, error) {
|
|
parts := strings.Split(strings.ReplaceAll(command, "\\ ", "\\"), " ")
|
|
if len(parts) < 2 {
|
|
return parts[0], []string{}, nil
|
|
}
|
|
args := []string{}
|
|
for _, arg := range parts[1:] {
|
|
parsed := strings.TrimSpace(strings.ReplaceAll(arg, "\\", " "))
|
|
if len(parsed) == 0 {
|
|
continue
|
|
}
|
|
args = append(args, parsed)
|
|
}
|
|
return parts[0], args, nil
|
|
}
|