/
client.go
267 lines (219 loc) · 6.45 KB
/
client.go
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package ntlmssp
import (
"fmt"
"strings"
)
type lmCompatibilityLevel int
const (
DefaultClientCompatibilityLevel lmCompatibilityLevel = 3
)
type Client struct {
compatibilityLevel lmCompatibilityLevel
defaultFlags uint32
domain string
password string
username string
workstation string
version *Version
negotiatedFlags uint32
negotiateMessage []byte
challengeMessage []byte
complete bool
securitySession *SecuritySession
}
func realClientChallenge() ([]byte, error) {
return nonce(8)
}
func realExportedSessionKey() ([]byte, error) {
return nonce(16)
}
var (
generateClientChallenge = realClientChallenge
generateExportedSessionKey = realExportedSessionKey
)
func NewClient(options ...func(*Client) error) (*Client, error) {
c := &Client{}
// Set the defaults
if err := c.SetOption(SetCompatibilityLevel(DefaultClientCompatibilityLevel)); err != nil {
return nil, err
}
if err := c.SetOption(options...); err != nil {
return nil, err
}
return c, nil
}
func defaultClientFlags() uint32 {
flags := uint32(0)
flags = ntlmsspNegotiateUnicode.Set(flags)
flags = ntlmsspNegotiateSign.Set(flags)
flags = ntlmsspNegotiateSeal.Set(flags)
flags = ntlmsspNegotiateAlwaysSign.Set(flags)
flags = ntlmsspNegotiateTargetInfo.Set(flags)
flags = ntlmsspNegotiate128.Set(flags)
flags = ntlmsspNegotiateKeyExch.Set(flags)
flags = ntlmsspNegotiate56.Set(flags)
return flags
}
func (c *Client) SetOption(options ...func(*Client) error) error {
for _, option := range options {
if err := option(c); err != nil {
return err
}
}
return nil
}
func SetCompatibilityLevel(level lmCompatibilityLevel) func(*Client) error {
return func(c *Client) error {
flags := defaultClientFlags()
// Ideally these should be constants if there's official naming for them
switch level {
case 0: // LM Auth and NTLMv1 Auth
flags = ntlmsspNegotiateLMKey.Set(flags)
flags = ntlmsspNegotiateNTLM.Set(flags)
case 1: // LM Auth and NTLMv1 Auth with Extended Session Security (NTLM2)
flags = ntlmsspNegotiateNTLM.Set(flags)
flags = ntlmsspNegotiateExtendedSessionsecurity.Set(flags)
case 2: // NTLMv1 Auth with Extended Session Security (NTLM2)
fallthrough
case 3, 4, 5: // NTLMv2 Auth
flags = ntlmsspNegotiateExtendedSessionsecurity.Set(flags)
default:
return fmt.Errorf("invalid compatibility level(0-5): %d", level)
}
c.compatibilityLevel = level
c.defaultFlags = flags
return nil
}
}
func SetDomain(domain string) func(*Client) error {
return func(c *Client) error {
c.domain = strings.TrimSpace(domain)
return nil
}
}
func SetUserInfo(username, password string) func(*Client) error {
return func(c *Client) error {
c.username = username
c.password = password
return nil
}
}
func SetWorkstation(workstation string) func(*Client) error {
return func(c *Client) error {
c.workstation = strings.TrimSpace(workstation)
return nil
}
}
func SetVersion(version *Version) func(*Client) error {
return func(c *Client) error {
c.version = version
return nil
}
}
func (c *Client) Authenticate(input []byte, bindings *ChannelBindings) ([]byte, error) {
if input != nil {
return c.processChallengeMessage(input, bindings)
}
return c.newNegotiateMessage()
}
func (c *Client) newNegotiateMessage() ([]byte, error) {
m := &negotiateMessage{
negotiateMessageFields: negotiateMessageFields{
messageHeader: newMessageHeader(ntLmNegotiate),
NegotiateFlags: c.defaultFlags,
},
DomainName: c.domain,
Workstation: c.workstation,
Version: c.version,
}
b, err := m.Marshal()
if err != nil {
return nil, err
}
// Store the message bytes in case we need to generate a MIC
c.negotiateMessage = b
return b, nil
}
func (c *Client) processChallengeMessage(input []byte, bindings *ChannelBindings) ([]byte, error) {
cm := &challengeMessage{}
if err := cm.Unmarshal(input); err != nil {
return nil, err
}
// Store the message bytes in case we need to generate a MIC
c.challengeMessage = input
c.negotiatedFlags = cm.NegotiateFlags
if ntlmsspNegotiateUnicode.IsSet(c.negotiatedFlags) {
c.negotiatedFlags = ntlmNegotiateOEM.Unset(c.negotiatedFlags)
}
// Set anonymous flag
if c.username == "" && c.password == "" {
c.negotiatedFlags = ntlmsspAnonymous.Set(c.negotiatedFlags)
}
clientChallenge, err := generateClientChallenge()
if err != nil {
return nil, err
}
lmChallengeResponse, err := lmChallengeResponse(c.negotiatedFlags, c.compatibilityLevel, clientChallenge, c.username, c.password, c.domain, cm)
if err != nil {
return nil, err
}
targetInfo, err := cm.TargetInfo.Clone()
if err != nil {
return nil, err
}
ntChallengeResponse, keyExchangeKey, err := ntChallengeResponse(c.negotiatedFlags, c.compatibilityLevel, clientChallenge, c.username, c.password, c.domain, cm, lmChallengeResponse, *targetInfo, bindings)
if err != nil {
return nil, err
}
var encryptedRandomSessionKey, exportedSessionKey []byte
if ntlmsspNegotiateKeyExch.IsSet(c.negotiatedFlags) {
exportedSessionKey, err = generateExportedSessionKey()
if err != nil {
return nil, err
}
encryptedRandomSessionKey, err = encryptRC4K(keyExchangeKey, exportedSessionKey)
if err != nil {
return nil, err
}
} else {
exportedSessionKey = keyExchangeKey
}
if ntlmsspNegotiateSeal.IsSet(c.negotiatedFlags) || ntlmsspNegotiateSign.IsSet(c.negotiatedFlags) {
c.securitySession, err = newSecuritySession(c.negotiatedFlags, exportedSessionKey, sourceClient)
if err != nil {
return nil, err
}
}
am := &authenticateMessage{
authenticateMessageFields: authenticateMessageFields{
messageHeader: newMessageHeader(ntLmAuthenticate),
NegotiateFlags: c.negotiatedFlags,
},
LmChallengeResponse: lmChallengeResponse,
NtChallengeResponse: ntChallengeResponse,
DomainName: c.domain,
UserName: c.username,
Workstation: c.workstation,
EncryptedRandomSessionKey: encryptedRandomSessionKey,
Version: c.version,
// Needed for computing the MIC
ExportedSessionKey: exportedSessionKey,
TargetInfo: *targetInfo,
}
if err := am.UpdateMIC(concat(c.negotiateMessage, c.challengeMessage)); err != nil {
return nil, err
}
b, err := am.Marshal()
if err != nil {
return nil, err
}
// Mark transaction as complete
c.complete = true
return b, nil
}
func (c *Client) Complete() bool {
return c.complete
}
func (c *Client) SecuritySession() *SecuritySession {
return c.securitySession
}