blob: ebc5d3d09737c072ad86874d7a733f1e913bf200 [file] [log] [blame]
Pragya Arya324337e2020-02-20 14:35:08 +05301package messages
2
3import (
4 "fmt"
5 "time"
6
7 "github.com/jcmturner/gofork/encoding/asn1"
8 "gopkg.in/jcmturner/gokrb5.v7/asn1tools"
9 "gopkg.in/jcmturner/gokrb5.v7/crypto"
10 "gopkg.in/jcmturner/gokrb5.v7/iana"
11 "gopkg.in/jcmturner/gokrb5.v7/iana/asnAppTag"
12 "gopkg.in/jcmturner/gokrb5.v7/iana/keyusage"
13 "gopkg.in/jcmturner/gokrb5.v7/iana/msgtype"
14 "gopkg.in/jcmturner/gokrb5.v7/krberror"
15 "gopkg.in/jcmturner/gokrb5.v7/types"
16)
17
18// KRBPriv implements RFC 4120 type: https://tools.ietf.org/html/rfc4120#section-5.7.1.
19type KRBPriv struct {
20 PVNO int `asn1:"explicit,tag:0"`
21 MsgType int `asn1:"explicit,tag:1"`
22 EncPart types.EncryptedData `asn1:"explicit,tag:3"`
23 DecryptedEncPart EncKrbPrivPart `asn1:"optional,omitempty"` // Not part of ASN1 bytes so marked as optional so unmarshalling works
24}
25
26// EncKrbPrivPart is the encrypted part of KRB_PRIV.
27type EncKrbPrivPart struct {
28 UserData []byte `asn1:"explicit,tag:0"`
29 Timestamp time.Time `asn1:"generalized,optional,explicit,tag:1"`
30 Usec int `asn1:"optional,explicit,tag:2"`
31 SequenceNumber int64 `asn1:"optional,explicit,tag:3"`
32 SAddress types.HostAddress `asn1:"explicit,tag:4"`
33 RAddress types.HostAddress `asn1:"optional,explicit,tag:5"`
34}
35
36// NewKRBPriv returns a new KRBPriv type.
37func NewKRBPriv(part EncKrbPrivPart) KRBPriv {
38 return KRBPriv{
39 PVNO: iana.PVNO,
40 MsgType: msgtype.KRB_PRIV,
41 DecryptedEncPart: part,
42 }
43}
44
45// Unmarshal bytes b into the KRBPriv struct.
46func (k *KRBPriv) Unmarshal(b []byte) error {
47 _, err := asn1.UnmarshalWithParams(b, k, fmt.Sprintf("application,explicit,tag:%v", asnAppTag.KRBPriv))
48 if err != nil {
49 return processUnmarshalReplyError(b, err)
50 }
51 expectedMsgType := msgtype.KRB_PRIV
52 if k.MsgType != expectedMsgType {
53 return krberror.NewErrorf(krberror.KRBMsgError, "message ID does not indicate a KRB_PRIV. Expected: %v; Actual: %v", expectedMsgType, k.MsgType)
54 }
55 return nil
56}
57
58// Unmarshal bytes b into the EncKrbPrivPart struct.
59func (k *EncKrbPrivPart) Unmarshal(b []byte) error {
60 _, err := asn1.UnmarshalWithParams(b, k, fmt.Sprintf("application,explicit,tag:%v", asnAppTag.EncKrbPrivPart))
61 if err != nil {
62 return krberror.Errorf(err, krberror.EncodingError, "KRB_PRIV unmarshal error")
63 }
64 return nil
65}
66
67// Marshal the KRBPriv.
68func (k *KRBPriv) Marshal() ([]byte, error) {
69 tk := KRBPriv{
70 PVNO: k.PVNO,
71 MsgType: k.MsgType,
72 EncPart: k.EncPart,
73 }
74 b, err := asn1.Marshal(tk)
75 if err != nil {
76 return []byte{}, err
77 }
78 b = asn1tools.AddASNAppTag(b, asnAppTag.KRBPriv)
79 return b, nil
80}
81
82// EncryptEncPart encrypts the DecryptedEncPart within the KRBPriv.
83// Use to prepare for marshaling.
84func (k *KRBPriv) EncryptEncPart(key types.EncryptionKey) error {
85 b, err := asn1.Marshal(k.DecryptedEncPart)
86 if err != nil {
87 return err
88 }
89 b = asn1tools.AddASNAppTag(b, asnAppTag.EncKrbPrivPart)
90 k.EncPart, err = crypto.GetEncryptedData(b, key, keyusage.KRB_PRIV_ENCPART, 1)
91 if err != nil {
92 return err
93 }
94 return nil
95}
96
97// DecryptEncPart decrypts the encrypted part of the KRBPriv message.
98func (k *KRBPriv) DecryptEncPart(key types.EncryptionKey) error {
99 b, err := crypto.DecryptEncPart(k.EncPart, key, keyusage.KRB_PRIV_ENCPART)
100 if err != nil {
101 return fmt.Errorf("error decrypting KRBPriv EncPart: %v", err)
102 }
103 err = k.DecryptedEncPart.Unmarshal(b)
104 if err != nil {
105 return fmt.Errorf("error unmarshaling encrypted part: %v", err)
106 }
107 return nil
108}