telebit/vendor/github.com/jcmturner/gokrb5/v8/kadmin/message.go

115 lines
2.7 KiB
Go

package kadmin
import (
"bytes"
"encoding/binary"
"errors"
"fmt"
"math"
"github.com/jcmturner/gokrb5/v8/messages"
"github.com/jcmturner/gokrb5/v8/types"
)
const (
verisonHex = "ff80"
)
// Request message for changing password.
type Request struct {
APREQ messages.APReq
KRBPriv messages.KRBPriv
}
// Reply message for a password change.
type Reply struct {
MessageLength int
Version int
APREPLength int
APREP messages.APRep
KRBPriv messages.KRBPriv
KRBError messages.KRBError
IsKRBError bool
ResultCode uint16
Result string
}
// Marshal a Request into a byte slice.
func (m *Request) Marshal() (b []byte, err error) {
b = []byte{255, 128} // protocol version number: contains the hex constant 0xff80 (big-endian integer).
ab, e := m.APREQ.Marshal()
if e != nil {
err = fmt.Errorf("error marshaling AP_REQ: %v", e)
return
}
if len(ab) > math.MaxUint16 {
err = errors.New("length of AP_REQ greater then max Uint16 size")
return
}
al := make([]byte, 2)
binary.BigEndian.PutUint16(al, uint16(len(ab)))
b = append(b, al...)
b = append(b, ab...)
pb, e := m.KRBPriv.Marshal()
if e != nil {
err = fmt.Errorf("error marshaling KRB_Priv: %v", e)
return
}
b = append(b, pb...)
if len(b)+2 > math.MaxUint16 {
err = errors.New("length of message greater then max Uint16 size")
return
}
ml := make([]byte, 2)
binary.BigEndian.PutUint16(ml, uint16(len(b)+2))
b = append(ml, b...)
return
}
// Unmarshal a byte slice into a Reply.
func (m *Reply) Unmarshal(b []byte) error {
m.MessageLength = int(binary.BigEndian.Uint16(b[0:2]))
m.Version = int(binary.BigEndian.Uint16(b[2:4]))
if m.Version != 1 {
return fmt.Errorf("kadmin reply has incorrect protocol version number: %d", m.Version)
}
m.APREPLength = int(binary.BigEndian.Uint16(b[4:6]))
if m.APREPLength != 0 {
err := m.APREP.Unmarshal(b[6 : 6+m.APREPLength])
if err != nil {
return err
}
err = m.KRBPriv.Unmarshal(b[6+m.APREPLength : m.MessageLength])
if err != nil {
return err
}
} else {
m.IsKRBError = true
m.KRBError.Unmarshal(b[6:m.MessageLength])
m.ResultCode, m.Result = parseResponse(m.KRBError.EData)
}
return nil
}
func parseResponse(b []byte) (c uint16, s string) {
c = binary.BigEndian.Uint16(b[0:2])
buf := bytes.NewBuffer(b[2:])
m := make([]byte, len(b)-2)
binary.Read(buf, binary.BigEndian, &m)
s = string(m)
return
}
// Decrypt the encrypted part of the KRBError within the change password Reply.
func (m *Reply) Decrypt(key types.EncryptionKey) error {
if m.IsKRBError {
return m.KRBError
}
err := m.KRBPriv.DecryptEncPart(key)
if err != nil {
return err
}
m.ResultCode, m.Result = parseResponse(m.KRBPriv.DecryptedEncPart.UserData)
return nil
}