request.go

Documentation: github.com/go-ldap/ldap/v3

     1  package ldap
     2  
     3  import (
     4  	"errors"
     5  
     6  	ber "github.com/go-asn1-ber/asn1-ber"
     7  )
     8  
     9  var (
    10  	errRespChanClosed = errors.New("ldap: response channel closed")
    11  	errCouldNotRetMsg = errors.New("ldap: could not retrieve message")
    12  	// ErrNilConnection is returned if doRequest is called with a nil connection.
    13  	ErrNilConnection = errors.New("ldap: conn is nil, expected net.Conn")
    14  )
    15  
    16  type request interface {
    17  	appendTo(*ber.Packet) error
    18  }
    19  
    20  type requestFunc func(*ber.Packet) error
    21  
    22  func (f requestFunc) appendTo(p *ber.Packet) error {
    23  	return f(p)
    24  }
    25  
    26  func (l *Conn) doRequest(req request) (*messageContext, error) {
    27  	if l == nil || l.conn == nil {
    28  		return nil, ErrNilConnection
    29  	}
    30  
    31  	packet := ber.Encode(ber.ClassUniversal, ber.TypeConstructed, ber.TagSequence, nil, "LDAP Request")
    32  	packet.AppendChild(ber.NewInteger(ber.ClassUniversal, ber.TypePrimitive, ber.TagInteger, l.nextMessageID(), "MessageID"))
    33  	if err := req.appendTo(packet); err != nil {
    34  		return nil, err
    35  	}
    36  
    37  	if l.Debug {
    38  		l.Debug.PrintPacket(packet)
    39  	}
    40  
    41  	msgCtx, err := l.sendMessage(packet)
    42  	if err != nil {
    43  		return nil, err
    44  	}
    45  	l.Debug.Printf("%d: returning", msgCtx.id)
    46  	return msgCtx, nil
    47  }
    48  
    49  func (l *Conn) readPacket(msgCtx *messageContext) (*ber.Packet, error) {
    50  	l.Debug.Printf("%d: waiting for response", msgCtx.id)
    51  	packetResponse, ok := <-msgCtx.responses
    52  	if !ok {
    53  		return nil, NewError(ErrorNetwork, errRespChanClosed)
    54  	}
    55  	packet, err := packetResponse.ReadPacket()
    56  	l.Debug.Printf("%d: got response %p", msgCtx.id, packet)
    57  	if err != nil {
    58  		return nil, err
    59  	}
    60  
    61  	if packet == nil {
    62  		return nil, NewError(ErrorNetwork, errCouldNotRetMsg)
    63  	}
    64  
    65  	if l.Debug {
    66  		if err = addLDAPDescriptions(packet); err != nil {
    67  			return nil, err
    68  		}
    69  		l.Debug.PrintPacket(packet)
    70  	}
    71  	return packet, nil
    72  }
    73  
    74  func getReferral(err error, packet *ber.Packet) (referral string) {
    75  	if !IsErrorWithCode(err, LDAPResultReferral) {
    76  		return ""
    77  	}
    78  
    79  	if len(packet.Children) < 2 {
    80  		return ""
    81  	}
    82  
    83  	// The packet Tag itself (of child 2) is generally a ber.TagObjectDescriptor with referrals however OpenLDAP
    84  	// seemingly returns a ber.Tag.GeneralizedTime. Every currently tested LDAP server which returns referrals returns
    85  	// an ASN.1 BER packet with the Type of ber.TypeConstructed and Class of ber.ClassApplication however. Thus this
    86  	// check expressly checks these fields instead.
    87  	//
    88  	// Related Issues:
    89  	//   - https://github.com/authelia/authelia/issues/4199 (downstream)
    90  	if len(packet.Children[1].Children) == 0 || (packet.Children[1].TagType != ber.TypeConstructed || packet.Children[1].ClassType != ber.ClassApplication) {
    91  		return ""
    92  	}
    93  
    94  	var ok bool
    95  
    96  	for _, child := range packet.Children[1].Children {
    97  		// The referral URI itself should be contained within a child which has a Tag of ber.BitString or
    98  		// ber.TagPrintableString, and the Type of ber.TypeConstructed and the Class of ClassContext. As soon as any of
    99  		// these conditions is not true  we can skip this child.
   100  		if (child.Tag != ber.TagBitString && child.Tag != ber.TagPrintableString) || child.TagType != ber.TypeConstructed || child.ClassType != ber.ClassContext {
   101  			continue
   102  		}
   103  
   104  		if referral, ok = child.Children[0].Value.(string); ok {
   105  			return referral
   106  		}
   107  	}
   108  
   109  	return ""
   110  }
   111
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