Issue 177 matcheddn (#191)

* * Changes for adding support for matchedDN parsing

* * Replace getLDAPResultCode with GetLDAPError

* * 'err' shadowed in some places fixed.

* * Adding doc comment for GetLDAPError()

Author: koushik2506

add.go

@@ -106,9 +106,9 @@ func (l *Conn) Add(addRequest *AddRequest) error {
 	}
 
 	if packet.Children[1].Tag == ApplicationAddResponse {
-		resultCode, resultDescription := getLDAPResultCode(packet)
-		if resultCode != 0 {
-			return NewError(resultCode, errors.New(resultDescription))
+		err := GetLDAPError(packet)
+		if err != nil {
+			return err
 		}
 	} else {
 		log.Printf("Unexpected Response: %d", packet.Children[1].Tag)

bind.go

@@ -79,7 +79,7 @@ func (l *Conn) SimpleBind(simpleBindRequest *SimpleBindRequest) (*SimpleBindResu
 	}
 
 	if l.Debug {
-		if err := addLDAPDescriptions(packet); err != nil {
+		if err = addLDAPDescriptions(packet); err != nil {
 			return nil, err
 		}
 		ber.PrintPacket(packet)
@@ -91,20 +91,16 @@ func (l *Conn) SimpleBind(simpleBindRequest *SimpleBindRequest) (*SimpleBindResu
 
 	if len(packet.Children) == 3 {
 		for _, child := range packet.Children[2].Children {
-			decodedChild, err := DecodeControl(child)
-			if err != nil {
-				return nil, fmt.Errorf("failed to decode child control: %s", err)
+			decodedChild, decodeErr := DecodeControl(child)
+			if decodeErr != nil {
+				return nil, fmt.Errorf("failed to decode child control: %s", decodeErr)
 			}
 			result.Controls = append(result.Controls, decodedChild)
 		}
 	}
 
-	resultCode, resultDescription := getLDAPResultCode(packet)
-	if resultCode != 0 {
-		return result, NewError(resultCode, errors.New(resultDescription))
-	}
-
-	return result, nil
+	err = GetLDAPError(packet)
+	return result, err
 }
 
 // Bind performs a bind with the given username and password.

compare.go

@@ -68,15 +68,15 @@ func (l *Conn) Compare(dn, attribute, value string) (bool, error) {
 	}
 
 	if packet.Children[1].Tag == ApplicationCompareResponse {
-		resultCode, resultDescription := getLDAPResultCode(packet)
+		err := GetLDAPError(packet)
 
 		switch {
-		case resultCode == LDAPResultCompareTrue:
+		case IsErrorWithCode(err, LDAPResultCompareTrue):
 			return true, nil
-		case resultCode == LDAPResultCompareFalse:
+		case IsErrorWithCode(err, LDAPResultCompareFalse):
 			return false, nil
 		default:
-			return false, NewError(resultCode, errors.New(resultDescription))
+			return false, err
 		}
 	}
 	return false, fmt.Errorf("unexpected Response: %d", packet.Children[1].Tag)

conn.go

@@ -275,18 +275,18 @@ func (l *Conn) StartTLS(config *tls.Config) error {
 		ber.PrintPacket(packet)
 	}
 
-	if resultCode, message := getLDAPResultCode(packet); resultCode == LDAPResultSuccess {
+	if err := GetLDAPError(packet); err == nil {
 		conn := tls.Client(l.conn, config)
 
-		if err := conn.Handshake(); err != nil {
+		if connErr := conn.Handshake(); connErr != nil {
 			l.Close()
-			return NewError(ErrorNetwork, fmt.Errorf("TLS handshake failed (%v)", err))
+			return NewError(ErrorNetwork, fmt.Errorf("TLS handshake failed (%v)", connErr))
 		}
 
 		l.isTLS = true
 		l.conn = conn
 	} else {
-		return NewError(resultCode, fmt.Errorf("ldap: cannot StartTLS (%s)", message))
+		return err
 	}
 	go l.reader()
 

del.go

@@ -71,9 +71,9 @@ func (l *Conn) Del(delRequest *DelRequest) error {
 	}
 
 	if packet.Children[1].Tag == ApplicationDelResponse {
-		resultCode, resultDescription := getLDAPResultCode(packet)
-		if resultCode != 0 {
-			return NewError(resultCode, errors.New(resultDescription))
+		err := GetLDAPError(packet)
+		if err != nil {
+			return err
 		}
 	} else {
 		log.Printf("Unexpected Response: %d", packet.Children[1].Tag)

error.go

@@ -176,35 +176,44 @@ var LDAPResultCodeMap = map[uint16]string{
 	ErrorEmptyPassword:      "Empty password not allowed by the client",
 }
 
-func getLDAPResultCode(packet *ber.Packet) (code uint16, description string) {
-	if packet == nil {
-		return ErrorUnexpectedResponse, "Empty packet"
-	} else if len(packet.Children) >= 2 {
-		response := packet.Children[1]
-		if response == nil {
-			return ErrorUnexpectedResponse, "Empty response in packet"
-		}
-		if response.ClassType == ber.ClassApplication && response.TagType == ber.TypeConstructed && len(response.Children) >= 3 {
-			// Children[1].Children[2] is the diagnosticMessage which is guaranteed to exist as seen here: https://tools.ietf.org/html/rfc4511#section-4.1.9
-			return uint16(response.Children[0].Value.(int64)), response.Children[2].Value.(string)
-		}
-	}
-
-	return ErrorNetwork, "Invalid packet format"
-}
-
 // Error holds LDAP error information
 type Error struct {
 	// Err is the underlying error
 	Err error
 	// ResultCode is the LDAP error code
 	ResultCode uint16
+	// MatchedDN is the matchedDN returned if any
+	MatchedDN string
 }
 
 func (e *Error) Error() string {
 	return fmt.Sprintf("LDAP Result Code %d %q: %s", e.ResultCode, LDAPResultCodeMap[e.ResultCode], e.Err.Error())
 }
 
+// GetLDAPError creates an Error out of a BER packet representing a LDAPResult
+// The return is an error object. It can be casted to a Error structure.
+// This function returns nil if resultCode in the LDAPResult sequence is success(0).
+func GetLDAPError(packet *ber.Packet) error {
+	if packet == nil {
+		return &Error{ResultCode: ErrorUnexpectedResponse, Err: fmt.Errorf("Empty packet")}
+	} else if len(packet.Children) >= 2 {
+		response := packet.Children[1]
+		if response == nil {
+			return &Error{ResultCode: ErrorUnexpectedResponse, Err: fmt.Errorf("Empty response in packet")}
+		}
+		if response.ClassType == ber.ClassApplication && response.TagType == ber.TypeConstructed && len(response.Children) >= 3 {
+			resultCode := uint16(response.Children[0].Value.(int64))
+			if resultCode == 0 { // No error
+				return nil
+			}
+			return &Error{ResultCode: resultCode, MatchedDN: response.Children[1].Value.(string),
+				Err: fmt.Errorf(response.Children[2].Value.(string))}
+		}
+	}
+
+	return &Error{ResultCode: ErrorNetwork, Err: fmt.Errorf("Invalid packet format")}
+}
+
 // NewError creates an LDAP error with the given code and underlying error
 func NewError(resultCode uint16, err error) error {
 	return &Error{ResultCode: resultCode, Err: err}

error_test.go

@@ -13,9 +13,9 @@ import (
 // TestNilPacket tests that nil packets don't cause a panic.
 func TestNilPacket(t *testing.T) {
 	// Test for nil packet
-	code, _ := getLDAPResultCode(nil)
-	if code != ErrorUnexpectedResponse {
-		t.Errorf("Should have an 'ErrorUnexpectedResponse' error in nil packets, got: %v", code)
+	err := GetLDAPError(nil)
+	if !IsErrorWithCode(err, ErrorUnexpectedResponse) {
+		t.Errorf("Should have an 'ErrorUnexpectedResponse' error in nil packets, got: %v", err)
 	}
 
 	// Test for nil result
@@ -24,10 +24,10 @@ func TestNilPacket(t *testing.T) {
 		nil, // Can't be nil
 	}
 	pack := &ber.Packet{Children: kids}
-	code, _ = getLDAPResultCode(pack)
+	err = GetLDAPError(pack)
 
-	if code != ErrorUnexpectedResponse {
-		t.Errorf("Should have an 'ErrorUnexpectedResponse' error in nil packets, got: %v", code)
+	if !IsErrorWithCode(err, ErrorUnexpectedResponse) {
+		t.Errorf("Should have an 'ErrorUnexpectedResponse' error in nil packets, got: %v", err)
 	}
 }
 

ldap.go

@@ -270,9 +270,9 @@ func addRequestDescriptions(packet *ber.Packet) error {
 }
 
 func addDefaultLDAPResponseDescriptions(packet *ber.Packet) error {
-	resultCode, _ := getLDAPResultCode(packet)
-	packet.Children[1].Children[0].Description = "Result Code (" + LDAPResultCodeMap[resultCode] + ")"
-	packet.Children[1].Children[1].Description = "Matched DN"
+	err := GetLDAPError(packet)
+	packet.Children[1].Children[0].Description = "Result Code (" + LDAPResultCodeMap[err.(*Error).ResultCode] + ")"
+	packet.Children[1].Children[1].Description = "Matched DN (" + err.(*Error).MatchedDN + ")"
 	packet.Children[1].Children[2].Description = "Error Message"
 	if len(packet.Children[1].Children) > 3 {
 		packet.Children[1].Children[3].Description = "Referral"

ldap_test.go

@@ -271,3 +271,32 @@ func TestCompare(t *testing.T) {
 
 	fmt.Printf("TestCompare: -> %v\n", sr)
 }
+
+func TestMatchDNError(t *testing.T) {
+	fmt.Printf("TestMatchDNError: starting..\n")
+
+	l, err := Dial("tcp", fmt.Sprintf("%s:%d", ldapServer, ldapPort))
+	if err != nil {
+		t.Fatal(err.Error())
+	}
+	defer l.Close()
+
+	wrongBase := "ou=roups,dc=umich,dc=edu"
+
+	searchRequest := NewSearchRequest(
+		wrongBase,
+		ScopeWholeSubtree, DerefAlways, 0, 0, false,
+		filter[0],
+		attributes,
+		nil)
+
+	_, err = l.Search(searchRequest)
+
+	if err == nil {
+		t.Errorf("Expected Error, got nil")
+		return
+	}
+
+	fmt.Printf("TestMatchDNError: err: %s\n", err.Error())
+
+}

moddn.go

@@ -91,9 +91,9 @@ func (l *Conn) ModifyDN(m *ModifyDNRequest) error {
 	}
 
 	if packet.Children[1].Tag == ApplicationModifyDNResponse {
-		resultCode, resultDescription := getLDAPResultCode(packet)
-		if resultCode != 0 {
-			return NewError(resultCode, errors.New(resultDescription))
+		err := GetLDAPError(packet)
+		if err != nil {
+			return err
 		}
 	} else {
 		log.Printf("Unexpected Response: %d", packet.Children[1].Tag)