mirror of
https://github.com/go-gitea/gitea
synced 2024-11-14 01:35:54 +01:00
22770c324d
Signed-off-by: Andrew Thornton <art27@cantab.net>
517 lines
14 KiB
Go
517 lines
14 KiB
Go
package ldap
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import (
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"crypto/tls"
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"errors"
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"fmt"
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"log"
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"net"
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"net/url"
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"sync"
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"sync/atomic"
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"time"
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"gopkg.in/asn1-ber.v1"
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)
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const (
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// MessageQuit causes the processMessages loop to exit
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MessageQuit = 0
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// MessageRequest sends a request to the server
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MessageRequest = 1
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// MessageResponse receives a response from the server
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MessageResponse = 2
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// MessageFinish indicates the client considers a particular message ID to be finished
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MessageFinish = 3
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// MessageTimeout indicates the client-specified timeout for a particular message ID has been reached
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MessageTimeout = 4
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)
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const (
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// DefaultLdapPort default ldap port for pure TCP connection
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DefaultLdapPort = "389"
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// DefaultLdapsPort default ldap port for SSL connection
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DefaultLdapsPort = "636"
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)
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// PacketResponse contains the packet or error encountered reading a response
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type PacketResponse struct {
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// Packet is the packet read from the server
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Packet *ber.Packet
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// Error is an error encountered while reading
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Error error
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}
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// ReadPacket returns the packet or an error
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func (pr *PacketResponse) ReadPacket() (*ber.Packet, error) {
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if (pr == nil) || (pr.Packet == nil && pr.Error == nil) {
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return nil, NewError(ErrorNetwork, errors.New("ldap: could not retrieve response"))
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}
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return pr.Packet, pr.Error
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}
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type messageContext struct {
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id int64
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// close(done) should only be called from finishMessage()
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done chan struct{}
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// close(responses) should only be called from processMessages(), and only sent to from sendResponse()
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responses chan *PacketResponse
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}
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// sendResponse should only be called within the processMessages() loop which
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// is also responsible for closing the responses channel.
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func (msgCtx *messageContext) sendResponse(packet *PacketResponse) {
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select {
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case msgCtx.responses <- packet:
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// Successfully sent packet to message handler.
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case <-msgCtx.done:
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// The request handler is done and will not receive more
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// packets.
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}
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}
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type messagePacket struct {
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Op int
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MessageID int64
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Packet *ber.Packet
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Context *messageContext
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}
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type sendMessageFlags uint
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const (
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startTLS sendMessageFlags = 1 << iota
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)
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// Conn represents an LDAP Connection
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type Conn struct {
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// requestTimeout is loaded atomically
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// so we need to ensure 64-bit alignment on 32-bit platforms.
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requestTimeout int64
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conn net.Conn
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isTLS bool
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closing uint32
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closeErr atomic.Value
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isStartingTLS bool
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Debug debugging
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chanConfirm chan struct{}
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messageContexts map[int64]*messageContext
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chanMessage chan *messagePacket
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chanMessageID chan int64
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wgClose sync.WaitGroup
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outstandingRequests uint
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messageMutex sync.Mutex
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}
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var _ Client = &Conn{}
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// DefaultTimeout is a package-level variable that sets the timeout value
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// used for the Dial and DialTLS methods.
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//
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// WARNING: since this is a package-level variable, setting this value from
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// multiple places will probably result in undesired behaviour.
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var DefaultTimeout = 60 * time.Second
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// Dial connects to the given address on the given network using net.Dial
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// and then returns a new Conn for the connection.
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func Dial(network, addr string) (*Conn, error) {
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c, err := net.DialTimeout(network, addr, DefaultTimeout)
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if err != nil {
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return nil, NewError(ErrorNetwork, err)
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}
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conn := NewConn(c, false)
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conn.Start()
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return conn, nil
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}
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// DialTLS connects to the given address on the given network using tls.Dial
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// and then returns a new Conn for the connection.
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func DialTLS(network, addr string, config *tls.Config) (*Conn, error) {
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c, err := tls.DialWithDialer(&net.Dialer{Timeout: DefaultTimeout}, network, addr, config)
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if err != nil {
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return nil, NewError(ErrorNetwork, err)
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}
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conn := NewConn(c, true)
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conn.Start()
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return conn, nil
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}
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// DialURL connects to the given ldap URL vie TCP using tls.Dial or net.Dial if ldaps://
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// or ldap:// specified as protocol. On success a new Conn for the connection
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// is returned.
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func DialURL(addr string) (*Conn, error) {
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lurl, err := url.Parse(addr)
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if err != nil {
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return nil, NewError(ErrorNetwork, err)
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}
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host, port, err := net.SplitHostPort(lurl.Host)
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if err != nil {
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// we asume that error is due to missing port
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host = lurl.Host
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port = ""
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}
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switch lurl.Scheme {
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case "ldap":
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if port == "" {
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port = DefaultLdapPort
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}
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return Dial("tcp", net.JoinHostPort(host, port))
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case "ldaps":
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if port == "" {
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port = DefaultLdapsPort
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}
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tlsConf := &tls.Config{
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ServerName: host,
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}
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return DialTLS("tcp", net.JoinHostPort(host, port), tlsConf)
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}
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return nil, NewError(ErrorNetwork, fmt.Errorf("Unknown scheme '%s'", lurl.Scheme))
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}
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// NewConn returns a new Conn using conn for network I/O.
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func NewConn(conn net.Conn, isTLS bool) *Conn {
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return &Conn{
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conn: conn,
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chanConfirm: make(chan struct{}),
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chanMessageID: make(chan int64),
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chanMessage: make(chan *messagePacket, 10),
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messageContexts: map[int64]*messageContext{},
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requestTimeout: 0,
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isTLS: isTLS,
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}
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}
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// Start initializes goroutines to read responses and process messages
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func (l *Conn) Start() {
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go l.reader()
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go l.processMessages()
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l.wgClose.Add(1)
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}
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// IsClosing returns whether or not we're currently closing.
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func (l *Conn) IsClosing() bool {
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return atomic.LoadUint32(&l.closing) == 1
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}
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// setClosing sets the closing value to true
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func (l *Conn) setClosing() bool {
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return atomic.CompareAndSwapUint32(&l.closing, 0, 1)
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}
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// Close closes the connection.
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func (l *Conn) Close() {
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l.messageMutex.Lock()
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defer l.messageMutex.Unlock()
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if l.setClosing() {
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l.Debug.Printf("Sending quit message and waiting for confirmation")
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l.chanMessage <- &messagePacket{Op: MessageQuit}
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<-l.chanConfirm
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close(l.chanMessage)
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l.Debug.Printf("Closing network connection")
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if err := l.conn.Close(); err != nil {
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log.Println(err)
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}
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l.wgClose.Done()
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}
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l.wgClose.Wait()
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}
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// SetTimeout sets the time after a request is sent that a MessageTimeout triggers
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func (l *Conn) SetTimeout(timeout time.Duration) {
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if timeout > 0 {
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atomic.StoreInt64(&l.requestTimeout, int64(timeout))
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}
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}
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// Returns the next available messageID
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func (l *Conn) nextMessageID() int64 {
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if messageID, ok := <-l.chanMessageID; ok {
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return messageID
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}
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return 0
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}
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// StartTLS sends the command to start a TLS session and then creates a new TLS Client
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func (l *Conn) StartTLS(config *tls.Config) error {
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if l.isTLS {
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return NewError(ErrorNetwork, errors.New("ldap: already encrypted"))
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}
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packet := ber.Encode(ber.ClassUniversal, ber.TypeConstructed, ber.TagSequence, nil, "LDAP Request")
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packet.AppendChild(ber.NewInteger(ber.ClassUniversal, ber.TypePrimitive, ber.TagInteger, l.nextMessageID(), "MessageID"))
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request := ber.Encode(ber.ClassApplication, ber.TypeConstructed, ApplicationExtendedRequest, nil, "Start TLS")
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request.AppendChild(ber.NewString(ber.ClassContext, ber.TypePrimitive, 0, "1.3.6.1.4.1.1466.20037", "TLS Extended Command"))
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packet.AppendChild(request)
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l.Debug.PrintPacket(packet)
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msgCtx, err := l.sendMessageWithFlags(packet, startTLS)
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if err != nil {
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return err
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}
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defer l.finishMessage(msgCtx)
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l.Debug.Printf("%d: waiting for response", msgCtx.id)
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packetResponse, ok := <-msgCtx.responses
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if !ok {
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return NewError(ErrorNetwork, errors.New("ldap: response channel closed"))
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}
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packet, err = packetResponse.ReadPacket()
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l.Debug.Printf("%d: got response %p", msgCtx.id, packet)
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if err != nil {
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return err
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}
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if l.Debug {
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if err := addLDAPDescriptions(packet); err != nil {
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l.Close()
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return err
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}
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ber.PrintPacket(packet)
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}
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if err := GetLDAPError(packet); err == nil {
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conn := tls.Client(l.conn, config)
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if connErr := conn.Handshake(); connErr != nil {
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l.Close()
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return NewError(ErrorNetwork, fmt.Errorf("TLS handshake failed (%v)", connErr))
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}
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l.isTLS = true
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l.conn = conn
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} else {
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return err
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}
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go l.reader()
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return nil
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}
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// TLSConnectionState returns the client's TLS connection state.
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// The return values are their zero values if StartTLS did
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// not succeed.
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func (l *Conn) TLSConnectionState() (state tls.ConnectionState, ok bool) {
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tc, ok := l.conn.(*tls.Conn)
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if !ok {
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return
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}
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return tc.ConnectionState(), true
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}
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func (l *Conn) sendMessage(packet *ber.Packet) (*messageContext, error) {
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return l.sendMessageWithFlags(packet, 0)
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}
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func (l *Conn) sendMessageWithFlags(packet *ber.Packet, flags sendMessageFlags) (*messageContext, error) {
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if l.IsClosing() {
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return nil, NewError(ErrorNetwork, errors.New("ldap: connection closed"))
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}
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l.messageMutex.Lock()
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l.Debug.Printf("flags&startTLS = %d", flags&startTLS)
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if l.isStartingTLS {
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l.messageMutex.Unlock()
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return nil, NewError(ErrorNetwork, errors.New("ldap: connection is in startls phase"))
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}
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if flags&startTLS != 0 {
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if l.outstandingRequests != 0 {
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l.messageMutex.Unlock()
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return nil, NewError(ErrorNetwork, errors.New("ldap: cannot StartTLS with outstanding requests"))
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}
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l.isStartingTLS = true
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}
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l.outstandingRequests++
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l.messageMutex.Unlock()
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responses := make(chan *PacketResponse)
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messageID := packet.Children[0].Value.(int64)
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message := &messagePacket{
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Op: MessageRequest,
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MessageID: messageID,
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Packet: packet,
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Context: &messageContext{
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id: messageID,
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done: make(chan struct{}),
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responses: responses,
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},
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}
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l.sendProcessMessage(message)
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return message.Context, nil
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}
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func (l *Conn) finishMessage(msgCtx *messageContext) {
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close(msgCtx.done)
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if l.IsClosing() {
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return
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}
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l.messageMutex.Lock()
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l.outstandingRequests--
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if l.isStartingTLS {
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l.isStartingTLS = false
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}
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l.messageMutex.Unlock()
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message := &messagePacket{
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Op: MessageFinish,
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MessageID: msgCtx.id,
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}
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l.sendProcessMessage(message)
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}
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func (l *Conn) sendProcessMessage(message *messagePacket) bool {
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l.messageMutex.Lock()
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defer l.messageMutex.Unlock()
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if l.IsClosing() {
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return false
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}
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l.chanMessage <- message
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return true
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}
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func (l *Conn) processMessages() {
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defer func() {
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if err := recover(); err != nil {
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log.Printf("ldap: recovered panic in processMessages: %v", err)
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}
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for messageID, msgCtx := range l.messageContexts {
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// If we are closing due to an error, inform anyone who
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// is waiting about the error.
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if l.IsClosing() && l.closeErr.Load() != nil {
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msgCtx.sendResponse(&PacketResponse{Error: l.closeErr.Load().(error)})
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}
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l.Debug.Printf("Closing channel for MessageID %d", messageID)
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close(msgCtx.responses)
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delete(l.messageContexts, messageID)
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}
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close(l.chanMessageID)
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close(l.chanConfirm)
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}()
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var messageID int64 = 1
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for {
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select {
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case l.chanMessageID <- messageID:
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messageID++
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case message := <-l.chanMessage:
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switch message.Op {
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case MessageQuit:
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l.Debug.Printf("Shutting down - quit message received")
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return
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case MessageRequest:
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// Add to message list and write to network
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l.Debug.Printf("Sending message %d", message.MessageID)
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buf := message.Packet.Bytes()
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_, err := l.conn.Write(buf)
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if err != nil {
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l.Debug.Printf("Error Sending Message: %s", err.Error())
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message.Context.sendResponse(&PacketResponse{Error: fmt.Errorf("unable to send request: %s", err)})
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close(message.Context.responses)
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break
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}
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// Only add to messageContexts if we were able to
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// successfully write the message.
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l.messageContexts[message.MessageID] = message.Context
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// Add timeout if defined
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requestTimeout := time.Duration(atomic.LoadInt64(&l.requestTimeout))
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if requestTimeout > 0 {
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go func() {
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defer func() {
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if err := recover(); err != nil {
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log.Printf("ldap: recovered panic in RequestTimeout: %v", err)
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}
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}()
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time.Sleep(requestTimeout)
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timeoutMessage := &messagePacket{
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Op: MessageTimeout,
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MessageID: message.MessageID,
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}
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l.sendProcessMessage(timeoutMessage)
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}()
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}
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case MessageResponse:
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l.Debug.Printf("Receiving message %d", message.MessageID)
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if msgCtx, ok := l.messageContexts[message.MessageID]; ok {
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msgCtx.sendResponse(&PacketResponse{message.Packet, nil})
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} else {
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log.Printf("Received unexpected message %d, %v", message.MessageID, l.IsClosing())
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ber.PrintPacket(message.Packet)
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}
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case MessageTimeout:
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// Handle the timeout by closing the channel
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// All reads will return immediately
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if msgCtx, ok := l.messageContexts[message.MessageID]; ok {
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l.Debug.Printf("Receiving message timeout for %d", message.MessageID)
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msgCtx.sendResponse(&PacketResponse{message.Packet, errors.New("ldap: connection timed out")})
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delete(l.messageContexts, message.MessageID)
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close(msgCtx.responses)
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}
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case MessageFinish:
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l.Debug.Printf("Finished message %d", message.MessageID)
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if msgCtx, ok := l.messageContexts[message.MessageID]; ok {
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delete(l.messageContexts, message.MessageID)
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close(msgCtx.responses)
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}
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}
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}
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}
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}
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func (l *Conn) reader() {
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cleanstop := false
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defer func() {
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if err := recover(); err != nil {
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log.Printf("ldap: recovered panic in reader: %v", err)
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}
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if !cleanstop {
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l.Close()
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}
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}()
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for {
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if cleanstop {
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l.Debug.Printf("reader clean stopping (without closing the connection)")
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return
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}
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packet, err := ber.ReadPacket(l.conn)
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if err != nil {
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// A read error is expected here if we are closing the connection...
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if !l.IsClosing() {
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l.closeErr.Store(fmt.Errorf("unable to read LDAP response packet: %s", err))
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l.Debug.Printf("reader error: %s", err.Error())
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}
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return
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}
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addLDAPDescriptions(packet)
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if len(packet.Children) == 0 {
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l.Debug.Printf("Received bad ldap packet")
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continue
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}
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l.messageMutex.Lock()
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if l.isStartingTLS {
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cleanstop = true
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}
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l.messageMutex.Unlock()
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message := &messagePacket{
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Op: MessageResponse,
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MessageID: packet.Children[0].Value.(int64),
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Packet: packet,
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}
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if !l.sendProcessMessage(message) {
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return
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}
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}
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}
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