package sftp
import (
"bytes"
"encoding"
"encoding/binary"
"errors"
"fmt"
"io"
"os"
"reflect"
)
var (
errLongPacket = errors.New("packet too long")
errShortPacket = errors.New("packet too short")
errUnknownExtendedPacket = errors.New("unknown extended packet")
)
const (
maxMsgLength = 256 * 1024
debugDumpTxPacket = false
debugDumpRxPacket = false
debugDumpTxPacketBytes = false
debugDumpRxPacketBytes = false
)
func marshalUint32(b []byte, v uint32) []byte {
return append(b, byte(v>>24), byte(v>>16), byte(v>>8), byte(v))
}
func marshalUint64(b []byte, v uint64) []byte {
return marshalUint32(marshalUint32(b, uint32(v>>32)), uint32(v))
}
func marshalString(b []byte, v string) []byte {
return append(marshalUint32(b, uint32(len(v))), v...)
}
func marshalFileInfo(b []byte, fi os.FileInfo) []byte {
// attributes variable struct, and also variable per protocol version
// spec version 3 attributes:
// uint32 flags
// uint64 size present only if flag SSH_FILEXFER_ATTR_SIZE
// uint32 uid present only if flag SSH_FILEXFER_ATTR_UIDGID
// uint32 gid present only if flag SSH_FILEXFER_ATTR_UIDGID
// uint32 permissions present only if flag SSH_FILEXFER_ATTR_PERMISSIONS
// uint32 atime present only if flag SSH_FILEXFER_ACMODTIME
// uint32 mtime present only if flag SSH_FILEXFER_ACMODTIME
// uint32 extended_count present only if flag SSH_FILEXFER_ATTR_EXTENDED
// string extended_type
// string extended_data
// ... more extended data (extended_type - extended_data pairs),
// so that number of pairs equals extended_count
flags, fileStat := fileStatFromInfo(fi)
b = marshalUint32(b, flags)
if flags&sshFileXferAttrSize != 0 {
b = marshalUint64(b, fileStat.Size)
}
if flags&sshFileXferAttrUIDGID != 0 {
b = marshalUint32(b, fileStat.UID)
b = marshalUint32(b, fileStat.GID)
}
if flags&sshFileXferAttrPermissions != 0 {
b = marshalUint32(b, fileStat.Mode)
}
if flags&sshFileXferAttrACmodTime != 0 {
b = marshalUint32(b, fileStat.Atime)
b = marshalUint32(b, fileStat.Mtime)
}
return b
}
func marshalStatus(b []byte, err StatusError) []byte {
b = marshalUint32(b, err.Code)
b = marshalString(b, err.msg)
b = marshalString(b, err.lang)
return b
}
func marshal(b []byte, v interface{}) []byte {
if v == nil {
return b
}
switch v := v.(type) {
case uint8:
return append(b, v)
case uint32:
return marshalUint32(b, v)
case uint64:
return marshalUint64(b, v)
case string:
return marshalString(b, v)
case os.FileInfo:
return marshalFileInfo(b, v)
default:
switch d := reflect.ValueOf(v); d.Kind() {
case reflect.Struct:
for i, n := 0, d.NumField(); i < n; i++ {
b = marshal(b, d.Field(i).Interface())
}
return b
case reflect.Slice:
for i, n := 0, d.Len(); i < n; i++ {
b = marshal(b, d.Index(i).Interface())
}
return b
default:
panic(fmt.Sprintf("marshal(%#v): cannot handle type %T", v, v))
}
}
}
func unmarshalUint32(b []byte) (uint32, []byte) {
v := uint32(b[3]) | uint32(b[2])<<8 | uint32(b[1])<<16 | uint32(b[0])<<24
return v, b[4:]
}
func unmarshalUint32Safe(b []byte) (uint32, []byte, error) {
var v uint32
if len(b) < 4 {
return 0, nil, errShortPacket
}
v, b = unmarshalUint32(b)
return v, b, nil
}
func unmarshalUint64(b []byte) (uint64, []byte) {
h, b := unmarshalUint32(b)
l, b := unmarshalUint32(b)
return uint64(h)<<32 | uint64(l), b
}
func unmarshalUint64Safe(b []byte) (uint64, []byte, error) {
var v uint64
if len(b) < 8 {
return 0, nil, errShortPacket
}
v, b = unmarshalUint64(b)
return v, b, nil
}
func unmarshalString(b []byte) (string, []byte) {
n, b := unmarshalUint32(b)
return string(b[:n]), b[n:]
}
func unmarshalStringSafe(b []byte) (string, []byte, error) {
n, b, err := unmarshalUint32Safe(b)
if err != nil {
return "", nil, err
}
if int64(n) > int64(len(b)) {
return "", nil, errShortPacket
}
return string(b[:n]), b[n:], nil
}
func unmarshalAttrs(b []byte) (*FileStat, []byte) {
flags, b := unmarshalUint32(b)
return unmarshalFileStat(flags, b)
}
func unmarshalFileStat(flags uint32, b []byte) (*FileStat, []byte) {
var fs FileStat
if flags&sshFileXferAttrSize == sshFileXferAttrSize {
fs.Size, b, _ = unmarshalUint64Safe(b)
}
if flags&sshFileXferAttrUIDGID == sshFileXferAttrUIDGID {
fs.UID, b, _ = unmarshalUint32Safe(b)
}
if flags&sshFileXferAttrUIDGID == sshFileXferAttrUIDGID {
fs.GID, b, _ = unmarshalUint32Safe(b)
}
if flags&sshFileXferAttrPermissions == sshFileXferAttrPermissions {
fs.Mode, b, _ = unmarshalUint32Safe(b)
}
if flags&sshFileXferAttrACmodTime == sshFileXferAttrACmodTime {
fs.Atime, b, _ = unmarshalUint32Safe(b)
fs.Mtime, b, _ = unmarshalUint32Safe(b)
}
if flags&sshFileXferAttrExtended == sshFileXferAttrExtended {
var count uint32
count, b, _ = unmarshalUint32Safe(b)
ext := make([]StatExtended, count)
for i := uint32(0); i < count; i++ {
var typ string
var data string
typ, b, _ = unmarshalStringSafe(b)
data, b, _ = unmarshalStringSafe(b)
ext[i] = StatExtended{
ExtType: typ,
ExtData: data,
}
}
fs.Extended = ext
}
return &fs, b
}
func unmarshalStatus(id uint32, data []byte) error {
sid, data := unmarshalUint32(data)
if sid != id {
return &unexpectedIDErr{id, sid}
}
code, data := unmarshalUint32(data)
msg, data, _ := unmarshalStringSafe(data)
lang, _, _ := unmarshalStringSafe(data)
return &StatusError{
Code: code,
msg: msg,
lang: lang,
}
}
type packetMarshaler interface {
marshalPacket() (header, payload []byte, err error)
}
func marshalPacket(m encoding.BinaryMarshaler) (header, payload []byte, err error) {
if m, ok := m.(packetMarshaler); ok {
return m.marshalPacket()
}
header, err = m.MarshalBinary()
return
}
// sendPacket marshals p according to RFC 4234.
func sendPacket(w io.Writer, m encoding.BinaryMarshaler) error {
header, payload, err := marshalPacket(m)
if err != nil {
return fmt.Errorf("binary marshaller failed: %w", err)
}
length := len(header) + len(payload) - 4 // subtract the uint32(length) from the start
if debugDumpTxPacketBytes {
debug("send packet: %s %d bytes %x%x", fxp(header[4]), length, header[5:], payload)
} else if debugDumpTxPacket {
debug("send packet: %s %d bytes", fxp(header[4]), length)
}
binary.BigEndian.PutUint32(header[:4], uint32(length))
if _, err := w.Write(header); err != nil {
return fmt.Errorf("failed to send packet: %w", err)
}
if len(payload) > 0 {
if _, err := w.Write(payload); err != nil {
return fmt.Errorf("failed to send packet payload: %w", err)
}
}
return nil
}
func recvPacket(r io.Reader, alloc *allocator, orderID uint32) (uint8, []byte, error) {
var b []byte
if alloc != nil {
b = alloc.GetPage(orderID)
} else {
b = make([]byte, 4)
}
if _, err := io.ReadFull(r, b[:4]); err != nil {
return 0, nil, err
}
length, _ := unmarshalUint32(b)
if length > maxMsgLength {
debug("recv packet %d bytes too long", length)
return 0, nil, errLongPacket
}
if length == 0 {
debug("recv packet of 0 bytes too short")
return 0, nil, errShortPacket
}
if alloc == nil {
b = make([]byte, length)
}
if _, err := io.ReadFull(r, b[:length]); err != nil {
debug("recv packet %d bytes: err %v", length, err)
return 0, nil, err
}
if debugDumpRxPacketBytes {
debug("recv packet: %s %d bytes %x", fxp(b[0]), length, b[1:length])
} else if debugDumpRxPacket {
debug("recv packet: %s %d bytes", fxp(b[0]), length)
}
return b[0], b[1:length], nil
}
type extensionPair struct {
Name string
Data string
}
func unmarshalExtensionPair(b []byte) (extensionPair, []byte, error) {
var ep extensionPair
var err error
ep.Name, b, err = unmarshalStringSafe(b)
if err != nil {
return ep, b, err
}
ep.Data, b, err = unmarshalStringSafe(b)
return ep, b, err
}
// Here starts the definition of packets along with their MarshalBinary
// implementations.
// Manually writing the marshalling logic wins us a lot of time and
// allocation.
type sshFxInitPacket struct {
Version uint32
Extensions []extensionPair
}
func (p *sshFxInitPacket) MarshalBinary() ([]byte, error) {
l := 4 + 1 + 4 // uint32(length) + byte(type) + uint32(version)
for _, e := range p.Extensions {
l += 4 + len(e.Name) + 4 + len(e.Data)
}
b := make([]byte, 4, l)
b = append(b, sshFxpInit)
b = marshalUint32(b, p.Version)
for _, e := range p.Extensions {
b = marshalString(b, e.Name)
b = marshalString(b, e.Data)
}
return b, nil
}
func (p *sshFxInitPacket) UnmarshalBinary(b []byte) error {
var err error
if p.Version, b, err = unmarshalUint32Safe(b); err != nil {
return err
}
for len(b) > 0 {
var ep extensionPair
ep, b, err = unmarshalExtensionPair(b)
if err != nil {
return err
}
p.Extensions = append(p.Extensions, ep)
}
return nil
}
type sshFxVersionPacket struct {
Version uint32
Extensions []sshExtensionPair
}
type sshExtensionPair struct {
Name, Data string
}
func (p *sshFxVersionPacket) MarshalBinary() ([]byte, error) {
l := 4 + 1 + 4 // uint32(length) + byte(type) + uint32(version)
for _, e := range p.Extensions {
l += 4 + len(e.Name) + 4 + len(e.Data)
}
b := make([]byte, 4, l)
b = append(b, sshFxpVersion)
b = marshalUint32(b, p.Version)
for _, e := range p.Extensions {
b = marshalString(b, e.Name)
b = marshalString(b, e.Data)
}
return b, nil
}
func marshalIDStringPacket(packetType byte, id uint32, str string) ([]byte, error) {
l := 4 + 1 + 4 + // uint32(length) + byte(type) + uint32(id)
4 + len(str)
b := make([]byte, 4, l)
b = append(b, packetType)
b = marshalUint32(b, id)
b = marshalString(b, str)
return b, nil
}
func unmarshalIDString(b []byte, id *uint32, str *string) error {
var err error
*id, b, err = unmarshalUint32Safe(b)
if err != nil {
return err
}
*str, _, err = unmarshalStringSafe(b)
return err
}
type sshFxpReaddirPacket struct {
ID uint32
Handle string
}
func (p *sshFxpReaddirPacket) id() uint32 { return p.ID }
func (p *sshFxpReaddirPacket) MarshalBinary() ([]byte, error) {
return marshalIDStringPacket(sshFxpReaddir, p.ID, p.Handle)
}
func (p *sshFxpReaddirPacket) UnmarshalBinary(b []byte) error {
return unmarshalIDString(b, &p.ID, &p.Handle)
}
type sshFxpOpendirPacket struct {
ID uint32
Path string
}
func (p *sshFxpOpendirPacket) id() uint32 { return p.ID }
func (p *sshFxpOpendirPacket) MarshalBinary() ([]byte, error) {
return marshalIDStringPacket(sshFxpOpendir, p.ID, p.Path)
}
func (p *sshFxpOpendirPacket) UnmarshalBinary(b []byte) error {
return unmarshalIDString(b, &p.ID, &p.Path)
}
type sshFxpLstatPacket struct {
ID uint32
Path string
}
func (p *sshFxpLstatPacket) id() uint32 { return p.ID }
func (p *sshFxpLstatPacket) MarshalBinary() ([]byte, error) {
return marshalIDStringPacket(sshFxpLstat, p.ID, p.Path)
}
func (p *sshFxpLstatPacket) UnmarshalBinary(b []byte) error {
return unmarshalIDString(b, &p.ID, &p.Path)
}
type sshFxpStatPacket struct {
ID uint32
Path string
}
func (p *sshFxpStatPacket) id() uint32 { return p.ID }
func (p *sshFxpStatPacket) MarshalBinary() ([]byte, error) {
return marshalIDStringPacket(sshFxpStat, p.ID, p.Path)
}
func (p *sshFxpStatPacket) UnmarshalBinary(b []byte) error {
return unmarshalIDString(b, &p.ID, &p.Path)
}
type sshFxpFstatPacket struct {
ID uint32
Handle string
}
func (p *sshFxpFstatPacket) id() uint32 { return p.ID }
func (p *sshFxpFstatPacket) MarshalBinary() ([]byte, error) {
return marshalIDStringPacket(sshFxpFstat, p.ID, p.Handle)
}
func (p *sshFxpFstatPacket) UnmarshalBinary(b []byte) error {
return unmarshalIDString(b, &p.ID, &p.Handle)
}
type sshFxpClosePacket struct {
ID uint32
Handle string
}
func (p *sshFxpClosePacket) id() uint32 { return p.ID }
func (p *sshFxpClosePacket) MarshalBinary() ([]byte, error) {
return marshalIDStringPacket(sshFxpClose, p.ID, p.Handle)
}
func (p *sshFxpClosePacket) UnmarshalBinary(b []byte) error {
return unmarshalIDString(b, &p.ID, &p.Handle)
}
type sshFxpRemovePacket struct {
ID uint32
Filename string
}
func (p *sshFxpRemovePacket) id() uint32 { return p.ID }
func (p *sshFxpRemovePacket) MarshalBinary() ([]byte, error) {
return marshalIDStringPacket(sshFxpRemove, p.ID, p.Filename)
}
func (p *sshFxpRemovePacket) UnmarshalBinary(b []byte) error {
return unmarshalIDString(b, &p.ID, &p.Filename)
}
type sshFxpRmdirPacket struct {
ID uint32
Path string
}
func (p *sshFxpRmdirPacket) id() uint32 { return p.ID }
func (p *sshFxpRmdirPacket) MarshalBinary() ([]byte, error) {
return marshalIDStringPacket(sshFxpRmdir, p.ID, p.Path)
}
func (p *sshFxpRmdirPacket) UnmarshalBinary(b []byte) error {
return unmarshalIDString(b, &p.ID, &p.Path)
}
type sshFxpSymlinkPacket struct {
ID uint32
Targetpath string
Linkpath string
}
func (p *sshFxpSymlinkPacket) id() uint32 { return p.ID }
func (p *sshFxpSymlinkPacket) MarshalBinary() ([]byte, error) {
l := 4 + 1 + 4 + // uint32(length) + byte(type) + uint32(id)
4 + len(p.Targetpath) +
4 + len(p.Linkpath)
b := make([]byte, 4, l)
b = append(b, sshFxpSymlink)
b = marshalUint32(b, p.ID)
b = marshalString(b, p.Targetpath)
b = marshalString(b, p.Linkpath)
return b, nil
}
func (p *sshFxpSymlinkPacket) UnmarshalBinary(b []byte) error {
var err error
if p.ID, b, err = unmarshalUint32Safe(b); err != nil {
return err
} else if p.Targetpath, b, err = unmarshalStringSafe(b); err != nil {
return err
} else if p.Linkpath, _, err = unmarshalStringSafe(b); err != nil {
return err
}
return nil
}
type sshFxpHardlinkPacket struct {
ID uint32
Oldpath string
Newpath string
}
func (p *sshFxpHardlinkPacket) id() uint32 { return p.ID }
func (p *sshFxpHardlinkPacket) MarshalBinary() ([]byte, error) {
const ext = "hardlink@openssh.com"
l := 4 + 1 + 4 + // uint32(length) + byte(type) + uint32(id)
4 + len(ext) +
4 + len(p.Oldpath) +
4 + len(p.Newpath)
b := make([]byte, 4, l)
b = append(b, sshFxpExtended)
b = marshalUint32(b, p.ID)
b = marshalString(b, ext)
b = marshalString(b, p.Oldpath)
b = marshalString(b, p.Newpath)
return b, nil
}
type sshFxpReadlinkPacket struct {
ID uint32
Path string
}
func (p *sshFxpReadlinkPacket) id() uint32 { return p.ID }
func (p *sshFxpReadlinkPacket) MarshalBinary() ([]byte, error) {
return marshalIDStringPacket(sshFxpReadlink, p.ID, p.Path)
}
func (p *sshFxpReadlinkPacket) UnmarshalBinary(b []byte) error {
return unmarshalIDString(b, &p.ID, &p.Path)
}
type sshFxpRealpathPacket struct {
ID uint32
Path string
}
func (p *sshFxpRealpathPacket) id() uint32 { return p.ID }
func (p *sshFxpRealpathPacket) MarshalBinary() ([]byte, error) {
return marshalIDStringPacket(sshFxpRealpath, p.ID, p.Path)
}
func (p *sshFxpRealpathPacket) UnmarshalBinary(b []byte) error {
return unmarshalIDString(b, &p.ID, &p.Path)
}
type sshFxpNameAttr struct {
Name string
LongName string
Attrs []interface{}
}
func (p *sshFxpNameAttr) MarshalBinary() ([]byte, error) {
var b []byte
b = marshalString(b, p.Name)
b = marshalString(b, p.LongName)
for _, attr := range p.Attrs {
b = marshal(b, attr)
}
return b, nil
}
type sshFxpNamePacket struct {
ID uint32
NameAttrs []*sshFxpNameAttr
}
func (p *sshFxpNamePacket) marshalPacket() ([]byte, []byte, error) {
l := 4 + 1 + 4 + // uint32(length) + byte(type) + uint32(id)
4
b := make([]byte, 4, l)
b = append(b, sshFxpName)
b = marshalUint32(b, p.ID)
b = marshalUint32(b, uint32(len(p.NameAttrs)))
var payload []byte
for _, na := range p.NameAttrs {
ab, err := na.MarshalBinary()
if err != nil {
return nil, nil, err
}
payload = append(payload, ab...)
}
return b, payload, nil
}
func (p *sshFxpNamePacket) MarshalBinary() ([]byte, error) {
header, payload, err := p.marshalPacket()
return append(header, payload...), err
}
type sshFxpOpenPacket struct {
ID uint32
Path string
Pflags uint32
Flags uint32 // ignored
}
func (p *sshFxpOpenPacket) id() uint32 { return p.ID }
func (p *sshFxpOpenPacket) MarshalBinary() ([]byte, error) {
l := 4 + 1 + 4 + // uint32(length) + byte(type) + uint32(id)
4 + len(p.Path) +
4 + 4
b := make([]byte, 4, l)
b = append(b, sshFxpOpen)
b = marshalUint32(b, p.ID)
b = marshalString(b, p.Path)
b = marshalUint32(b, p.Pflags)
b = marshalUint32(b, p.Flags)
return b, nil
}
func (p *sshFxpOpenPacket) UnmarshalBinary(b []byte) error {
var err error
if p.ID, b, err = unmarshalUint32Safe(b); err != nil {
return err
} else if p.Path, b, err = unmarshalStringSafe(b); err != nil {
return err
} else if p.Pflags, b, err = unmarshalUint32Safe(b); err != nil {
return err
} else if p.Flags, _, err = unmarshalUint32Safe(b); err != nil {
return err
}
return nil
}
type sshFxpReadPacket struct {
ID uint32
Len uint32
Offset uint64
Handle string
}
func (p *sshFxpReadPacket) id() uint32 { return p.ID }
func (p *sshFxpReadPacket) MarshalBinary() ([]byte, error) {
l := 4 + 1 + 4 + // uint32(length) + byte(type) + uint32(id)
4 + len(p.Handle) +
8 + 4 // uint64 + uint32
b := make([]byte, 4, l)
b = append(b, sshFxpRead)
b = marshalUint32(b, p.ID)
b = marshalString(b, p.Handle)
b = marshalUint64(b, p.Offset)
b = marshalUint32(b, p.Len)
return b, nil
}
func (p *sshFxpReadPacket) UnmarshalBinary(b []byte) error {
var err error
if p.ID, b, err = unmarshalUint32Safe(b); err != nil {
return err
} else if p.Handle, b, err = unmarshalStringSafe(b); err != nil {
return err
} else if p.Offset, b, err = unmarshalUint64Safe(b); err != nil {
return err
} else if p.Len, _, err = unmarshalUint32Safe(b); err != nil {
return err
}
return nil
}
// We need allocate bigger slices with extra capacity to avoid a re-allocation in sshFxpDataPacket.MarshalBinary
// So, we need: uint32(length) + byte(type) + uint32(id) + uint32(data_length)
const dataHeaderLen = 4 + 1 + 4 + 4
func (p *sshFxpReadPacket) getDataSlice(alloc *allocator, orderID uint32) []byte {
dataLen := p.Len
if dataLen > maxTxPacket {
dataLen = maxTxPacket
}
if alloc != nil {
// GetPage returns a slice with capacity = maxMsgLength this is enough to avoid new allocations in
// sshFxpDataPacket.MarshalBinary
return alloc.GetPage(orderID)[:dataLen]
}
// allocate with extra space for the header
return make([]byte, dataLen, dataLen+dataHeaderLen)
}
type sshFxpRenamePacket struct {
ID uint32
Oldpath string
Newpath string
}
func (p *sshFxpRenamePacket) id() uint32 { return p.ID }
func (p *sshFxpRenamePacket) MarshalBinary() ([]byte, error) {
l := 4 + 1 + 4 + // uint32(length) + byte(type) + uint32(id)
4 + len(p.Oldpath) +
4 + len(p.Newpath)
b := make([]byte, 4, l)
b = append(b, sshFxpRename)
b = marshalUint32(b, p.ID)
b = marshalString(b, p.Oldpath)
b = marshalString(b, p.Newpath)
return b, nil
}
func (p *sshFxpRenamePacket) UnmarshalBinary(b []byte) error {
var err error
if p.ID, b, err = unmarshalUint32Safe(b); err != nil {
return err
} else if p.Oldpath, b, err = unmarshalStringSafe(b); err != nil {
return err
} else if p.Newpath, _, err = unmarshalStringSafe(b); err != nil {
return err
}
return nil
}
type sshFxpPosixRenamePacket struct {
ID uint32
Oldpath string
Newpath string
}
func (p *sshFxpPosixRenamePacket) id() uint32 { return p.ID }
func (p *sshFxpPosixRenamePacket) MarshalBinary() ([]byte, error) {
const ext = "posix-rename@openssh.com"
l := 4 + 1 + 4 + // uint32(length) + byte(type) + uint32(id)
4 + len(ext) +
4 + len(p.Oldpath) +
4 + len(p.Newpath)
b := make([]byte, 4, l)
b = append(b, sshFxpExtended)
b = marshalUint32(b, p.ID)
b = marshalString(b, ext)
b = marshalString(b, p.Oldpath)
b = marshalString(b, p.Newpath)
return b, nil
}
type sshFxpWritePacket struct {
ID uint32
Length uint32
Offset uint64
Handle string
Data []byte
}
func (p *sshFxpWritePacket) id() uint32 { return p.ID }
func (p *sshFxpWritePacket) marshalPacket() ([]byte, []byte, error) {
l := 4 + 1 + 4 + // uint32(length) + byte(type) + uint32(id)
4 + len(p.Handle) +
8 + // uint64
4
b := make([]byte, 4, l)
b = append(b, sshFxpWrite)
b = marshalUint32(b, p.ID)
b = marshalString(b, p.Handle)
b = marshalUint64(b, p.Offset)
b = marshalUint32(b, p.Length)
return b, p.Data, nil
}
func (p *sshFxpWritePacket) MarshalBinary() ([]byte, error) {
header, payload, err := p.marshalPacket()
return append(header, payload...), err
}
func (p *sshFxpWritePacket) UnmarshalBinary(b []byte) error {
var err error
if p.ID, b, err = unmarshalUint32Safe(b); err != nil {
return err
} else if p.Handle, b, err = unmarshalStringSafe(b); err != nil {
return err
} else if p.Offset, b, err = unmarshalUint64Safe(b); err != nil {
return err
} else if p.Length, b, err = unmarshalUint32Safe(b); err != nil {
return err
} else if uint32(len(b)) < p.Length {
return errShortPacket
}
p.Data = b[:p.Length]
return nil
}
type sshFxpMkdirPacket struct {
ID uint32
Flags uint32 // ignored
Path string
}
func (p *sshFxpMkdirPacket) id() uint32 { return p.ID }
func (p *sshFxpMkdirPacket) MarshalBinary() ([]byte, error) {
l := 4 + 1 + 4 + // uint32(length) + byte(type) + uint32(id)
4 + len(p.Path) +
4 // uint32
b := make([]byte, 4, l)
b = append(b, sshFxpMkdir)
b = marshalUint32(b, p.ID)
b = marshalString(b, p.Path)
b = marshalUint32(b, p.Flags)
return b, nil
}
func (p *sshFxpMkdirPacket) UnmarshalBinary(b []byte) error {
var err error
if p.ID, b, err = unmarshalUint32Safe(b); err != nil {
return err
} else if p.Path, b, err = unmarshalStringSafe(b); err != nil {
return err
} else if p.Flags, _, err = unmarshalUint32Safe(b); err != nil {
return err
}
return nil
}
type sshFxpSetstatPacket struct {
ID uint32
Flags uint32
Path string
Attrs interface{}
}
type sshFxpFsetstatPacket struct {
ID uint32
Flags uint32
Handle string
Attrs interface{}
}
func (p *sshFxpSetstatPacket) id() uint32 { return p.ID }
func (p *sshFxpFsetstatPacket) id() uint32 { return p.ID }
func (p *sshFxpSetstatPacket) marshalPacket() ([]byte, []byte, error) {
l := 4 + 1 + 4 + // uint32(length) + byte(type) + uint32(id)
4 + len(p.Path) +
4 // uint32
b := make([]byte, 4, l)
b = append(b, sshFxpSetstat)
b = marshalUint32(b, p.ID)
b = marshalString(b, p.Path)
b = marshalUint32(b, p.Flags)
payload := marshal(nil, p.Attrs)
return b, payload, nil
}
func (p *sshFxpSetstatPacket) MarshalBinary() ([]byte, error) {
header, payload, err := p.marshalPacket()
return append(header, payload...), err
}
func (p *sshFxpFsetstatPacket) marshalPacket() ([]byte, []byte, error) {
l := 4 + 1 + 4 + // uint32(length) + byte(type) + uint32(id)
4 + len(p.Handle) +
4 // uint32
b := make([]byte, 4, l)
b = append(b, sshFxpFsetstat)
b = marshalUint32(b, p.ID)
b = marshalString(b, p.Handle)
b = marshalUint32(b, p.Flags)
payload := marshal(nil, p.Attrs)
return b, payload, nil
}
func (p *sshFxpFsetstatPacket) MarshalBinary() ([]byte, error) {
header, payload, err := p.marshalPacket()
return append(header, payload...), err
}
func (p *sshFxpSetstatPacket) UnmarshalBinary(b []byte) error {
var err error
if p.ID, b, err = unmarshalUint32Safe(b); err != nil {
return err
} else if p.Path, b, err = unmarshalStringSafe(b); err != nil {
return err
} else if p.Flags, b, err = unmarshalUint32Safe(b); err != nil {
return err
}
p.Attrs = b
return nil
}
func (p *sshFxpFsetstatPacket) UnmarshalBinary(b []byte) error {
var err error
if p.ID, b, err = unmarshalUint32Safe(b); err != nil {
return err
} else if p.Handle, b, err = unmarshalStringSafe(b); err != nil {
return err
} else if p.Flags, b, err = unmarshalUint32Safe(b); err != nil {
return err
}
p.Attrs = b
return nil
}
type sshFxpHandlePacket struct {
ID uint32
Handle string
}
func (p *sshFxpHandlePacket) MarshalBinary() ([]byte, error) {
l := 4 + 1 + 4 + // uint32(length) + byte(type) + uint32(id)
4 + len(p.Handle)
b := make([]byte, 4, l)
b = append(b, sshFxpHandle)
b = marshalUint32(b, p.ID)
b = marshalString(b, p.Handle)
return b, nil
}
type sshFxpStatusPacket struct {
ID uint32
StatusError
}
func (p *sshFxpStatusPacket) MarshalBinary() ([]byte, error) {
l := 4 + 1 + 4 + // uint32(length) + byte(type) + uint32(id)
4 +
4 + len(p.StatusError.msg) +
4 + len(p.StatusError.lang)
b := make([]byte, 4, l)
b = append(b, sshFxpStatus)
b = marshalUint32(b, p.ID)
b = marshalStatus(b, p.StatusError)
return b, nil
}
type sshFxpDataPacket struct {
ID uint32
Length uint32
Data []byte
}
func (p *sshFxpDataPacket) marshalPacket() ([]byte, []byte, error) {
l := 4 + 1 + 4 + // uint32(length) + byte(type) + uint32(id)
4
b := make([]byte, 4, l)
b = append(b, sshFxpData)
b = marshalUint32(b, p.ID)
b = marshalUint32(b, p.Length)
return b, p.Data, nil
}
// MarshalBinary encodes the receiver into a binary form and returns the result.
// To avoid a new allocation the Data slice must have a capacity >= Length + 9
//
// This is hand-coded rather than just append(header, payload...),
// in order to try and reuse the r.Data backing store in the packet.
func (p *sshFxpDataPacket) MarshalBinary() ([]byte, error) {
b := append(p.Data, make([]byte, dataHeaderLen)...)
copy(b[dataHeaderLen:], p.Data[:p.Length])
// b[0:4] will be overwritten with the length in sendPacket
b[4] = sshFxpData
binary.BigEndian.PutUint32(b[5:9], p.ID)
binary.BigEndian.PutUint32(b[9:13], p.Length)
return b, nil
}
func (p *sshFxpDataPacket) UnmarshalBinary(b []byte) error {
var err error
if p.ID, b, err = unmarshalUint32Safe(b); err != nil {
return err
} else if p.Length, b, err = unmarshalUint32Safe(b); err != nil {
return err
} else if uint32(len(b)) < p.Length {
return errShortPacket
}
p.Data = b[:p.Length]
return nil
}
type sshFxpStatvfsPacket struct {
ID uint32
Path string
}
func (p *sshFxpStatvfsPacket) id() uint32 { return p.ID }
func (p *sshFxpStatvfsPacket) MarshalBinary() ([]byte, error) {
const ext = "statvfs@openssh.com"
l := 4 + 1 + 4 + // uint32(length) + byte(type) + uint32(id)
4 + len(ext) +
4 + len(p.Path)
b := make([]byte, 4, l)
b = append(b, sshFxpExtended)
b = marshalUint32(b, p.ID)
b = marshalString(b, ext)
b = marshalString(b, p.Path)
return b, nil
}
// A StatVFS contains statistics about a filesystem.
type StatVFS struct {
ID uint32
Bsize uint64 /* file system block size */
Frsize uint64 /* fundamental fs block size */
Blocks uint64 /* number of blocks (unit f_frsize) */
Bfree uint64 /* free blocks in file system */
Bavail uint64 /* free blocks for non-root */
Files uint64 /* total file inodes */
Ffree uint64 /* free file inodes */
Favail uint64 /* free file inodes for to non-root */
Fsid uint64 /* file system id */
Flag uint64 /* bit mask of f_flag values */
Namemax uint64 /* maximum filename length */
}
// TotalSpace calculates the amount of total space in a filesystem.
func (p *StatVFS) TotalSpace() uint64 {
return p.Frsize * p.Blocks
}
// FreeSpace calculates the amount of free space in a filesystem.
func (p *StatVFS) FreeSpace() uint64 {
return p.Frsize * p.Bfree
}
// marshalPacket converts to ssh_FXP_EXTENDED_REPLY packet binary format
func (p *StatVFS) marshalPacket() ([]byte, []byte, error) {
header := []byte{0, 0, 0, 0, sshFxpExtendedReply}
var buf bytes.Buffer
err := binary.Write(&buf, binary.BigEndian, p)
return header, buf.Bytes(), err
}
// MarshalBinary encodes the StatVFS as an SSH_FXP_EXTENDED_REPLY packet.
func (p *StatVFS) MarshalBinary() ([]byte, error) {
header, payload, err := p.marshalPacket()
return append(header, payload...), err
}
type sshFxpFsyncPacket struct {
ID uint32
Handle string
}
func (p *sshFxpFsyncPacket) id() uint32 { return p.ID }
func (p *sshFxpFsyncPacket) MarshalBinary() ([]byte, error) {
const ext = "fsync@openssh.com"
l := 4 + 1 + 4 + // uint32(length) + byte(type) + uint32(id)
4 + len(ext) +
4 + len(p.Handle)
b := make([]byte, 4, l)
b = append(b, sshFxpExtended)
b = marshalUint32(b, p.ID)
b = marshalString(b, ext)
b = marshalString(b, p.Handle)
return b, nil
}
type sshFxpExtendedPacket struct {
ID uint32
ExtendedRequest string
SpecificPacket interface {
serverRespondablePacket
readonly() bool
}
}
func (p *sshFxpExtendedPacket) id() uint32 { return p.ID }
func (p *sshFxpExtendedPacket) readonly() bool {
if p.SpecificPacket == nil {
return true
}
return p.SpecificPacket.readonly()
}
func (p *sshFxpExtendedPacket) respond(svr *Server) responsePacket {
if p.SpecificPacket == nil {
return statusFromError(p.ID, nil)
}
return p.SpecificPacket.respond(svr)
}
func (p *sshFxpExtendedPacket) UnmarshalBinary(b []byte) error {
var err error
bOrig := b
if p.ID, b, err = unmarshalUint32Safe(b); err != nil {
return err
} else if p.ExtendedRequest, _, err = unmarshalStringSafe(b); err != nil {
return err
}
// specific unmarshalling
switch p.ExtendedRequest {
case "statvfs@openssh.com":
p.SpecificPacket = &sshFxpExtendedPacketStatVFS{}
case "posix-rename@openssh.com":
p.SpecificPacket = &sshFxpExtendedPacketPosixRename{}
case "hardlink@openssh.com":
p.SpecificPacket = &sshFxpExtendedPacketHardlink{}
default:
return fmt.Errorf("packet type %v: %w", p.SpecificPacket, errUnknownExtendedPacket)
}
return p.SpecificPacket.UnmarshalBinary(bOrig)
}
type sshFxpExtendedPacketStatVFS struct {
ID uint32
ExtendedRequest string
Path string
}
func (p *sshFxpExtendedPacketStatVFS) id() uint32 { return p.ID }
func (p *sshFxpExtendedPacketStatVFS) readonly() bool { return true }
func (p *sshFxpExtendedPacketStatVFS) UnmarshalBinary(b []byte) error {
var err error
if p.ID, b, err = unmarshalUint32Safe(b); err != nil {
return err
} else if p.ExtendedRequest, b, err = unmarshalStringSafe(b); err != nil {
return err
} else if p.Path, _, err = unmarshalStringSafe(b); err != nil {
return err
}
return nil
}
type sshFxpExtendedPacketPosixRename struct {
ID uint32
ExtendedRequest string
Oldpath string
Newpath string
}
func (p *sshFxpExtendedPacketPosixRename) id() uint32 { return p.ID }
func (p *sshFxpExtendedPacketPosixRename) readonly() bool { return false }
func (p *sshFxpExtendedPacketPosixRename) UnmarshalBinary(b []byte) error {
var err error
if p.ID, b, err = unmarshalUint32Safe(b); err != nil {
return err
} else if p.ExtendedRequest, b, err = unmarshalStringSafe(b); err != nil {
return err
} else if p.Oldpath, b, err = unmarshalStringSafe(b); err != nil {
return err
} else if p.Newpath, _, err = unmarshalStringSafe(b); err != nil {
return err
}
return nil
}
func (p *sshFxpExtendedPacketPosixRename) respond(s *Server) responsePacket {
err := os.Rename(p.Oldpath, p.Newpath)
return statusFromError(p.ID, err)
}
type sshFxpExtendedPacketHardlink struct {
ID uint32
ExtendedRequest string
Oldpath string
Newpath string
}
// https://github.com/openssh/openssh-portable/blob/master/PROTOCOL
func (p *sshFxpExtendedPacketHardlink) id() uint32 { return p.ID }
func (p *sshFxpExtendedPacketHardlink) readonly() bool { return true }
func (p *sshFxpExtendedPacketHardlink) UnmarshalBinary(b []byte) error {
var err error
if p.ID, b, err = unmarshalUint32Safe(b); err != nil {
return err
} else if p.ExtendedRequest, b, err = unmarshalStringSafe(b); err != nil {
return err
} else if p.Oldpath, b, err = unmarshalStringSafe(b); err != nil {
return err
} else if p.Newpath, _, err = unmarshalStringSafe(b); err != nil {
return err
}
return nil
}
func (p *sshFxpExtendedPacketHardlink) respond(s *Server) responsePacket {
err := os.Link(p.Oldpath, p.Newpath)
return statusFromError(p.ID, err)
}
