Move to ldap.v3 to fix #5928 (#6105)

Signed-off-by: Andrew Thornton <art27@cantab.net>

vendor/gopkg.in/ldap.v3/bind.go

@@ -0,0 +1,135 @@
+package ldap
+
+import (
+	"errors"
+	"fmt"
+
+	"gopkg.in/asn1-ber.v1"
+)
+
+// SimpleBindRequest represents a username/password bind operation
+type SimpleBindRequest struct {
+	// Username is the name of the Directory object that the client wishes to bind as
+	Username string
+	// Password is the credentials to bind with
+	Password string
+	// Controls are optional controls to send with the bind request
+	Controls []Control
+	// AllowEmptyPassword sets whether the client allows binding with an empty password
+	// (normally used for unauthenticated bind).
+	AllowEmptyPassword bool
+}
+
+// SimpleBindResult contains the response from the server
+type SimpleBindResult struct {
+	Controls []Control
+}
+
+// NewSimpleBindRequest returns a bind request
+func NewSimpleBindRequest(username string, password string, controls []Control) *SimpleBindRequest {
+	return &SimpleBindRequest{
+		Username:           username,
+		Password:           password,
+		Controls:           controls,
+		AllowEmptyPassword: false,
+	}
+}
+
+func (bindRequest *SimpleBindRequest) encode() *ber.Packet {
+	request := ber.Encode(ber.ClassApplication, ber.TypeConstructed, ApplicationBindRequest, nil, "Bind Request")
+	request.AppendChild(ber.NewInteger(ber.ClassUniversal, ber.TypePrimitive, ber.TagInteger, 3, "Version"))
+	request.AppendChild(ber.NewString(ber.ClassUniversal, ber.TypePrimitive, ber.TagOctetString, bindRequest.Username, "User Name"))
+	request.AppendChild(ber.NewString(ber.ClassContext, ber.TypePrimitive, 0, bindRequest.Password, "Password"))
+
+	return request
+}
+
+// SimpleBind performs the simple bind operation defined in the given request
+func (l *Conn) SimpleBind(simpleBindRequest *SimpleBindRequest) (*SimpleBindResult, error) {
+	if simpleBindRequest.Password == "" && !simpleBindRequest.AllowEmptyPassword {
+		return nil, NewError(ErrorEmptyPassword, errors.New("ldap: empty password not allowed by the client"))
+	}
+
+	packet := ber.Encode(ber.ClassUniversal, ber.TypeConstructed, ber.TagSequence, nil, "LDAP Request")
+	packet.AppendChild(ber.NewInteger(ber.ClassUniversal, ber.TypePrimitive, ber.TagInteger, l.nextMessageID(), "MessageID"))
+	encodedBindRequest := simpleBindRequest.encode()
+	packet.AppendChild(encodedBindRequest)
+	if len(simpleBindRequest.Controls) > 0 {
+		packet.AppendChild(encodeControls(simpleBindRequest.Controls))
+	}
+
+	if l.Debug {
+		ber.PrintPacket(packet)
+	}
+
+	msgCtx, err := l.sendMessage(packet)
+	if err != nil {
+		return nil, err
+	}
+	defer l.finishMessage(msgCtx)
+
+	packetResponse, ok := <-msgCtx.responses
+	if !ok {
+		return nil, NewError(ErrorNetwork, errors.New("ldap: response channel closed"))
+	}
+	packet, err = packetResponse.ReadPacket()
+	l.Debug.Printf("%d: got response %p", msgCtx.id, packet)
+	if err != nil {
+		return nil, err
+	}
+
+	if l.Debug {
+		if err = addLDAPDescriptions(packet); err != nil {
+			return nil, err
+		}
+		ber.PrintPacket(packet)
+	}
+
+	result := &SimpleBindResult{
+		Controls: make([]Control, 0),
+	}
+
+	if len(packet.Children) == 3 {
+		for _, child := range packet.Children[2].Children {
+			decodedChild, decodeErr := DecodeControl(child)
+			if decodeErr != nil {
+				return nil, fmt.Errorf("failed to decode child control: %s", decodeErr)
+			}
+			result.Controls = append(result.Controls, decodedChild)
+		}
+	}
+
+	err = GetLDAPError(packet)
+	return result, err
+}
+
+// Bind performs a bind with the given username and password.
+//
+// It does not allow unauthenticated bind (i.e. empty password). Use the UnauthenticatedBind method
+// for that.
+func (l *Conn) Bind(username, password string) error {
+	req := &SimpleBindRequest{
+		Username:           username,
+		Password:           password,
+		AllowEmptyPassword: false,
+	}
+	_, err := l.SimpleBind(req)
+	return err
+}
+
+// UnauthenticatedBind performs an unauthenticated bind.
+//
+// A username may be provided for trace (e.g. logging) purpose only, but it is normally not
+// authenticated or otherwise validated by the LDAP server.
+//
+// See https://tools.ietf.org/html/rfc4513#section-5.1.2 .
+// See https://tools.ietf.org/html/rfc4513#section-6.3.1 .
+func (l *Conn) UnauthenticatedBind(username string) error {
+	req := &SimpleBindRequest{
+		Username:           username,
+		Password:           "",
+		AllowEmptyPassword: true,
+	}
+	_, err := l.SimpleBind(req)
+	return err
+}