/
server-ctrl.go
590 lines (541 loc) · 14.6 KB
/
server-ctrl.go
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package ftpd
import (
"bufio"
"bytes"
"fmt"
"io"
"log"
"net"
"runtime"
"strconv"
"strings"
"sync/atomic"
"time"
"github.com/Edgaru089/ftpd/auth"
"github.com/Edgaru089/ftpd/mount"
)
// This file houses the protocol implementation for the Control connection.
// Data transfer types
const (
DataASCII = iota
DataImage
DataEBCDIC // Not supported
)
const (
DataStream = iota
DataBlock // Not supported
DataCompressed // Not supported
)
const (
DataConnActive = iota // Not supported
DataConnPassive
)
// FTP control connections are stateful!
type ctrlState struct {
auth auth.AccessType // current auth level (zero-value means no permission)
username string // only store the username, verified on (USER or) PASS command
wd string // working directory
datatype int // ASCII, Image or EBCDIC(not implemented)
//datamode int // Stream, Block or Compress(not implemented)
activePort, pasvPort int // Active(client-side) and Passive(server-side) ports
activeIP net.IP // Active mode target IP
dataConnMode int // Data Connect mode (Active or Passive)
pasvListener *net.TCPListener // Passive mode TCP Listener, nil if none
pasvConn *net.TCPConn // Passive mode Data Connection
inTransfer int32 // 0 or 1, Must be read/written by the atomic package!!!
transferError int32 // 0(no error) or 1(error), Must be atomic!!!
}
var defaultCtrlState = ctrlState{
wd: "/",
}
// The conn can be any ReadWriteCloser (can be the ones from net or crypto/tls).
func (s *Server) goCtrlConn(conn io.ReadWriteCloser) {
defer func() {
err := recover()
if err != nil {
stack := make([]byte, 8192)
stack = stack[:runtime.Stack(stack, false)]
log.Print("goCtrlConn: panic: ", err, ", stack trace:\n", string(stack))
}
}()
// recover goes after conn.Close
defer conn.Close()
// Hello!
writeFTPReplySingleline(conn, &s.buffer, 220)
// The FTP protocol is strictly Telnet(CRLF) based so
// we could just use bufio.Scanner with CRLF ending
sc := bufio.NewScanner(conn)
sc.Split(ScanCRLF)
// FTP controls are stateful!
state := defaultCtrlState
defer func() { // State cleanup
if state.pasvListener != nil {
state.pasvListener.Close()
}
if state.pasvConn != nil {
state.pasvConn.Close()
}
}()
for sc.Scan() {
nline := sc.Bytes()
s.doCtrlLine(nline, sc, &state, conn)
}
}
func (s *Server) doCtrlLine(line []byte, sc *bufio.Scanner, state *ctrlState, writer io.WriteCloser) {
// Reuse the server buffer
buf := &s.buffer
buf.Reset()
// Read the first word ended either by Space or CRLF
var cmd []byte
for i, c := range line {
if c == ' ' {
break
}
cmd = line[:i+1]
}
log.Printf("doLine: Line=\"%s\", Cmd=%s\n", line, cmd)
switch string(bytes.ToUpper(cmd)) {
// ----- ACCESS CONTROL COMMANDS ----- //
case "USER":
// param should begin after the command and a Space
param := string(line[len(cmd)+1:])
// Reset the auth level
state.auth = s.Auth.Login(param, "")
if state.auth != auth.NoPermission {
// Success
writeFTPReplySingleline(writer, buf, 230)
} else {
state.username = param
writeFTPReplySingleline(writer, buf, 331)
}
case "PASS":
if len(state.username) == 0 { // Invalid: PASS comes after USER
writeFTPReplySingleline(writer, buf, 503)
break
}
var param string
if len(cmd) == len(line) {
param = "\uffefINVALID\uffef"
} else {
param = string(line[len(cmd)+1:])
}
state.auth = s.Auth.Login(state.username, param)
if state.auth != auth.NoPermission {
writeFTPReplySingleline(writer, buf, 230)
} else {
state.username = param
writeFTPReplySingleline(writer, buf, 530)
}
case "CWD":
if !state.auth.HasAccess(auth.ReadOnly) {
writeFTPReplySingleline(writer, buf, 530)
break
}
param := string(line[len(cmd)+1:])
var target string
if param[0] == '/' {
target = param
} else {
if state.wd == "/" {
target = "/" + param
} else {
target = state.wd + "/" + param
}
}
stat, err := s.Node.Stat(target)
if target == "/" || (err == nil && stat.IsDirectory) { // A folder
state.wd = target
if state.wd != "/" && state.wd[len(state.wd)-1] == '/' {
state.wd = state.wd[:len(state.wd)-1]
}
writeFTPReplySingleline(writer, buf, 200)
} else {
log.Print("doLine: warning: CWD target folder \"", target, "\" Stat failed")
writeFTPReplySingleline(writer, buf, 501)
}
case "PWD":
if !state.auth.HasAccess(auth.ReadOnly) {
writeFTPReplySingleline(writer, buf, 530)
break
}
writeFTPReplySingleline(writer, buf, 257, state.wd)
case "CDUP":
if !state.auth.HasAccess(auth.ReadOnly) {
writeFTPReplySingleline(writer, buf, 530)
break
}
// TODO CDUP called on root directory
if state.wd == "/" {
writeFTPReplySingleline(writer, buf, 550)
break
}
newpath := state.wd[:strings.LastIndexByte(state.wd, '/')]
if len(newpath) == 0 {
newpath = "/"
}
stat, err := s.Node.Stat(newpath)
if err != nil || !stat.IsDirectory {
log.Print("doLine: warning: CDUP folder \"", state.wd, "\" -> \"", newpath, "\" Stat failed")
writeFTPReplySingleline(writer, buf, 550)
} else {
//log.Print("doLine: CDUP folder \"", state.wd, "\" -> \"", newpath, "\"")
state.wd = newpath
writeFTPReplySingleline(writer, buf, 200)
}
case "REIN":
(*state) = defaultCtrlState
writeFTPReplySingleline(writer, buf, 200)
case "QUIT":
writeFTPReplySingleline(writer, buf, 221)
writer.Close()
// ----- TRANSFER PARAMETER COMMANDS ----- //
case "PORT":
if !state.auth.HasAccess(auth.ReadOnly) {
writeFTPReplySingleline(writer, buf, 530)
break
}
param := line[len(cmd)+1:]
state.activeIP, state.activePort = parseHostPort(param)
state.dataConnMode = DataConnActive
writeFTPReplySingleline(writer, buf, 200)
case "PASV":
if !state.auth.HasAccess(auth.ReadOnly) {
writeFTPReplySingleline(writer, buf, 530)
break
}
// Close previous
if state.pasvListener != nil {
state.pasvListener.Close()
}
// target listen data address
addr := s.DataAddress
if len(addr) == 0 || addr == "0.0.0.0" {
if conn, ok := writer.(*net.TCPConn); ok {
// Ignoring error
addr, _, _ = net.SplitHostPort(conn.LocalAddr().String())
}
}
dport := s.alloPort()
if dport == 0 {
writeFTPReplySingleline(writer, buf, 421)
break
}
state.pasvPort = dport
l, err := net.Listen("tcp4", net.JoinHostPort(addr, strconv.Itoa(dport)))
state.pasvListener = l.(*net.TCPListener)
if err != nil {
writeFTPReplySingleline(writer, buf, 421)
log.Print("doCtrlLine: listen error: ", err)
break
}
_, pasvStr, err := net.SplitHostPort(state.pasvListener.Addr().String())
if err != nil {
writeFTPReplySingleline(writer, buf, 421)
break
}
pasvPort, err := strconv.Atoi(pasvStr)
if err != nil {
writeFTPReplySingleline(writer, buf, 421)
break
}
writeFTPReplySingleline(writer, buf, 227, packHostPortSlice(net.ParseIP(s.DataAddress), pasvPort))
case "TYPE":
if !state.auth.HasAccess(auth.ReadOnly) {
writeFTPReplySingleline(writer, buf, 530)
break
}
param := line[len(cmd)+1:]
switch string(param) {
case "A":
state.datatype = DataASCII
writeFTPReplySingleline(writer, buf, 200)
case "I":
state.datatype = DataImage
writeFTPReplySingleline(writer, buf, 200)
case "E":
writeFTPReplySingleline(writer, buf, 504)
default:
writeFTPReplySingleline(writer, buf, 501)
}
case "STRU":
if !state.auth.HasAccess(auth.ReadOnly) {
writeFTPReplySingleline(writer, buf, 530)
break
}
param := line[len(cmd)+1:]
switch string(param) {
case "F":
writeFTPReplySingleline(writer, buf, 200)
case "R", "P":
writeFTPReplySingleline(writer, buf, 504)
default:
writeFTPReplySingleline(writer, buf, 501)
}
case "MODE":
if !state.auth.HasAccess(auth.ReadOnly) {
writeFTPReplySingleline(writer, buf, 530)
break
}
param := line[len(cmd)+1:]
switch string(param) {
case "S":
//state.datamode = DataStream
writeFTPReplySingleline(writer, buf, 200)
case "B", "C":
writeFTPReplySingleline(writer, buf, 504)
default:
writeFTPReplySingleline(writer, buf, 501)
}
// ----- FTP SERVICE COMMANDS ----- //
case "ABOR":
if !state.auth.HasAccess(auth.ReadOnly) {
writeFTPReplySingleline(writer, buf, 530)
break
}
if state.pasvConn == nil {
writeFTPReplySingleline(writer, buf, 226)
break
}
if atomic.LoadInt32(&state.inTransfer) != 0 {
atomic.StoreInt32(&state.transferError, 1)
state.pasvConn.Close()
// Actively wait for the data connection to finish.
for atomic.LoadInt32(&state.inTransfer) != 0 {
//runtime.Gosched()
time.Sleep(time.Millisecond)
}
} else {
state.pasvConn.Close()
state.pasvConn = nil
}
writeFTPReplySingleline(writer, buf, 226)
// TODO Active Mode Data Connection
case "RETR":
if !state.auth.HasAccess(auth.ReadOnly) {
writeFTPReplySingleline(writer, buf, 530)
break
}
param := line[len(cmd)+1:]
f, err := s.Node.ReadFile(state.wd + "/" + string(param))
if err != nil {
writeFTPReplySingleline(writer, buf, 550)
} else {
s.writeToDataConn(f, sc, state, writer)
}
case "STOR":
if !state.auth.HasAccess(auth.ReadWrite) {
writeFTPReplySingleline(writer, buf, 530)
break
}
param := line[len(cmd)+1:]
f, err := s.Node.WriteFile(state.wd + "/" + string(param))
if err != nil {
writeFTPReplySingleline(writer, buf, 550)
} else {
s.readFromDataConn(f, sc, state, writer)
}
case "APPE":
if !state.auth.HasAccess(auth.ReadWrite) {
writeFTPReplySingleline(writer, buf, 530)
break
}
param := line[len(cmd)+1:]
f, err := s.Node.AppendFile(state.wd + "/" + string(param))
if err != nil {
writeFTPReplySingleline(writer, buf, 550)
} else {
s.readFromDataConn(f, sc, state, writer)
}
case "DELE":
if !state.auth.HasAccess(auth.ReadWrite) {
writeFTPReplySingleline(writer, buf, 530)
break
}
param := line[len(cmd)+1:]
err := s.Node.DeleteFile(state.wd + "/" + string(param))
if err != nil {
writeFTPReplySingleline(writer, buf, 550)
} else {
writeFTPReplySingleline(writer, buf, 200)
}
case "RMD":
if !state.auth.HasAccess(auth.ReadWrite) {
writeFTPReplySingleline(writer, buf, 530)
break
}
param := line[len(cmd)+1:]
err := s.Node.RemoveDirectory(state.wd + "/" + string(param))
if err != nil {
writeFTPReplySingleline(writer, buf, 550)
} else {
writeFTPReplySingleline(writer, buf, 200)
}
case "MKD":
if !state.auth.HasAccess(auth.ReadWrite) {
writeFTPReplySingleline(writer, buf, 530)
break
}
param := line[len(cmd)+1:]
err := s.Node.MakeDirectory(state.wd + "/" + string(param))
if err != nil {
writeFTPReplySingleline(writer, buf, 550)
} else {
writeFTPReplySingleline(writer, buf, 200)
}
// ----- RFC3659 EXTENSION COMMANDS ----- //
case "SIZE":
if !state.auth.HasAccess(auth.ReadOnly) {
writeFTPReplySingleline(writer, buf, 530)
break
}
param := state.wd + "/" + string(line[len(cmd)+1:])
if state.wd == "/" { // param="//dir"
param = param[1:]
}
stat, err := s.Node.Stat(param)
if err != nil {
writeFTPReplySingleline(writer, buf, 550)
} else {
writeFTPReplySingleline(writer, buf, 213, strconv.FormatInt(stat.Size, 10))
}
case "MDTM":
if !state.auth.HasAccess(auth.ReadOnly) {
writeFTPReplySingleline(writer, buf, 530)
break
}
param := state.wd + "/" + string(line[len(cmd)+1:])
if state.wd == "/" { // param="//dir"
param = param[1:]
}
stat, err := s.Node.Stat(param)
if err != nil {
writeFTPReplySingleline(writer, buf, 550)
} else {
writeFTPReplySingleline(writer, buf, 213, ftpTime(stat.LastModify))
}
case "MLST":
if !state.auth.HasAccess(auth.ReadOnly) {
writeFTPReplySingleline(writer, buf, 530)
break
}
var param string
if len(line) == len(cmd) {
param = state.wd
} else {
param = state.wd + "/" + string(line[len(cmd)+1:])
if state.wd == "/" { // param="//dir"
param = param[1:]
}
}
stat, err := s.Node.Stat(param)
if err != nil {
writeFTPReplySingleline(writer, buf, 550)
break
}
buf.WriteString("250- Listing starting\r\n ")
formatMLSXString(buf, &stat)
buf.WriteString("\r\n250 End\r\n")
buf.WriteTo(writer)
case "MLSD":
if !state.auth.HasAccess(auth.ReadOnly) {
writeFTPReplySingleline(writer, buf, 530)
break
}
var param string
if len(line) == len(cmd) {
param = state.wd
} else {
param = state.wd + "/" + string(line[len(cmd)+1:])
if state.wd == "/" { // param="//dir"
param = param[1:]
}
}
list, err := s.Node.List(param)
if err != nil {
if err == mount.ErrNotFolder {
writeFTPReplySingleline(writer, buf, 501)
} else {
writeFTPReplySingleline(writer, buf, 550)
}
break
}
s.writeToDataConn(newMLSDWriter(list), sc, state, writer)
case "LIST":
if !state.auth.HasAccess(auth.ReadOnly) {
writeFTPReplySingleline(writer, buf, 530)
break
}
list, err := s.Node.List(state.wd)
if err != nil {
if err == mount.ErrNotFolder {
writeFTPReplySingleline(writer, buf, 501)
} else {
writeFTPReplySingleline(writer, buf, 550)
}
break
}
var permstr string
switch state.auth {
case auth.ReadOnly:
permstr = "r--r--r--"
case auth.ReadWrite:
permstr = "rw-rw-rw-"
}
year := time.Now().Year()
// We need a new buffer for async send
buf := &bytes.Buffer{}
for _, f := range list {
if f.IsDirectory {
buf.WriteByte('d')
} else {
buf.WriteByte('-')
}
buf.WriteString(permstr)
buf.WriteString(" 1 user group ")
var t string
// Refer to https://cr.yp.to/ftp/list/binls.html for
// details on the /bin/ls format.
if f.LastModify.Year() != year {
t = f.LastModify.Format("Jan _2 2006")
} else {
t = f.LastModify.Format("Jan _2 15:04")
}
fmt.Fprintf(buf, "%12d %s %s\r\n", f.Size, t, f.Name)
}
s.writeToDataConn(buf, sc, state, writer)
// ----- OTHER EXTENSION COMMANDS ----- //
case "FEAT":
buf.WriteString("211- Features supported\r\n")
buf.Write(Features)
buf.WriteString("211 End\r\n")
_, err := buf.WriteTo(writer)
if err != nil {
writer.Close()
}
case "SYST":
// Write "UNIX Type: L8" as described in https://cr.yp.to/ftp/syst.html
buf.WriteString("215 UNIX Type: L8\r\n")
_, err := buf.WriteTo(writer)
if err != nil {
writer.Close()
}
case "ALLO", "NOOP":
writeFTPReplySingleline(writer, buf, 200)
case "ACCT", "STOU", "REST", "NLST", "SITE", "STAT":
writeFTPReplySingleline(writer, buf, 502) // Command not Implemented
default:
writeFTPReplySingleline(writer, buf, 500)
}
}
type mlsdWriter struct {
files []mount.File
bytes.Buffer
}
func newMLSDWriter(files []mount.File) io.Reader {
o := &mlsdWriter{files: files}
for _, f := range files {
formatMLSXString(o, &f)
o.WriteString("\r\n")
}
return o
}