1package messages
2
3import (
4	"fmt"
5	"time"
6
7	"github.com/jcmturner/gofork/encoding/asn1"
8	"github.com/jcmturner/gokrb5/v8/asn1tools"
9	"github.com/jcmturner/gokrb5/v8/crypto"
10	"github.com/jcmturner/gokrb5/v8/iana"
11	"github.com/jcmturner/gokrb5/v8/iana/asnAppTag"
12	"github.com/jcmturner/gokrb5/v8/iana/keyusage"
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// 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}
109