github.com/jcmturner/gokrb5/v8@v8.4.4/messages/KRBError.go (about)

     1  // Package messages implements Kerberos 5 message types and methods.
     2  package messages
     3  
     4  import (
     5  	"fmt"
     6  	"time"
     7  
     8  	"github.com/jcmturner/gofork/encoding/asn1"
     9  	"github.com/jcmturner/gokrb5/v8/asn1tools"
    10  	"github.com/jcmturner/gokrb5/v8/iana"
    11  	"github.com/jcmturner/gokrb5/v8/iana/asnAppTag"
    12  	"github.com/jcmturner/gokrb5/v8/iana/errorcode"
    13  	"github.com/jcmturner/gokrb5/v8/iana/msgtype"
    14  	"github.com/jcmturner/gokrb5/v8/krberror"
    15  	"github.com/jcmturner/gokrb5/v8/types"
    16  )
    17  
    18  // KRBError implements RFC 4120 KRB_ERROR: https://tools.ietf.org/html/rfc4120#section-5.9.1.
    19  type KRBError struct {
    20  	PVNO      int                 `asn1:"explicit,tag:0"`
    21  	MsgType   int                 `asn1:"explicit,tag:1"`
    22  	CTime     time.Time           `asn1:"generalized,optional,explicit,tag:2"`
    23  	Cusec     int                 `asn1:"optional,explicit,tag:3"`
    24  	STime     time.Time           `asn1:"generalized,explicit,tag:4"`
    25  	Susec     int                 `asn1:"explicit,tag:5"`
    26  	ErrorCode int32               `asn1:"explicit,tag:6"`
    27  	CRealm    string              `asn1:"generalstring,optional,explicit,tag:7"`
    28  	CName     types.PrincipalName `asn1:"optional,explicit,tag:8"`
    29  	Realm     string              `asn1:"generalstring,explicit,tag:9"`
    30  	SName     types.PrincipalName `asn1:"explicit,tag:10"`
    31  	EText     string              `asn1:"generalstring,optional,explicit,tag:11"`
    32  	EData     []byte              `asn1:"optional,explicit,tag:12"`
    33  }
    34  
    35  // NewKRBError creates a new KRBError.
    36  func NewKRBError(sname types.PrincipalName, realm string, code int32, etext string) KRBError {
    37  	t := time.Now().UTC()
    38  	return KRBError{
    39  		PVNO:      iana.PVNO,
    40  		MsgType:   msgtype.KRB_ERROR,
    41  		STime:     t,
    42  		Susec:     int((t.UnixNano() / int64(time.Microsecond)) - (t.Unix() * 1e6)),
    43  		ErrorCode: code,
    44  		SName:     sname,
    45  		Realm:     realm,
    46  		EText:     etext,
    47  	}
    48  }
    49  
    50  // Unmarshal bytes b into the KRBError struct.
    51  func (k *KRBError) Unmarshal(b []byte) error {
    52  	_, err := asn1.UnmarshalWithParams(b, k, fmt.Sprintf("application,explicit,tag:%v", asnAppTag.KRBError))
    53  	if err != nil {
    54  		return krberror.Errorf(err, krberror.EncodingError, "KRB_ERROR unmarshal error")
    55  	}
    56  	expectedMsgType := msgtype.KRB_ERROR
    57  	if k.MsgType != expectedMsgType {
    58  		return krberror.NewErrorf(krberror.KRBMsgError, "message ID does not indicate a KRB_ERROR. Expected: %v; Actual: %v", expectedMsgType, k.MsgType)
    59  	}
    60  	return nil
    61  }
    62  
    63  // Marshal a KRBError into bytes.
    64  func (k *KRBError) Marshal() ([]byte, error) {
    65  	b, err := asn1.Marshal(*k)
    66  	if err != nil {
    67  		return b, krberror.Errorf(err, krberror.EncodingError, "error marshaling KRBError")
    68  	}
    69  	b = asn1tools.AddASNAppTag(b, asnAppTag.KRBError)
    70  	return b, nil
    71  }
    72  
    73  // Error method implementing error interface on KRBError struct.
    74  func (k KRBError) Error() string {
    75  	etxt := fmt.Sprintf("KRB Error: %s", errorcode.Lookup(k.ErrorCode))
    76  	if k.EText != "" {
    77  		etxt = fmt.Sprintf("%s - %s", etxt, k.EText)
    78  	}
    79  	return etxt
    80  }
    81  
    82  func processUnmarshalReplyError(b []byte, err error) error {
    83  	switch err.(type) {
    84  	case asn1.StructuralError:
    85  		var krberr KRBError
    86  		tmperr := krberr.Unmarshal(b)
    87  		if tmperr != nil {
    88  			return krberror.Errorf(err, krberror.EncodingError, "failed to unmarshal KDC's reply")
    89  		}
    90  		return krberr
    91  	default:
    92  		return krberror.Errorf(err, krberror.EncodingError, "failed to unmarshal KDC's reply")
    93  	}
    94  }