1package pac
2
3import (
4	"bytes"
5	"errors"
6	"fmt"
7
8	"github.com/jcmturner/gokrb5/v8/crypto"
9	"github.com/jcmturner/gokrb5/v8/iana/keyusage"
10	"github.com/jcmturner/gokrb5/v8/types"
11	"github.com/jcmturner/rpc/v2/mstypes"
12	"github.com/jcmturner/rpc/v2/ndr"
13)
14
15// https://msdn.microsoft.com/en-us/library/cc237931.aspx
16
17// CredentialsInfo implements https://msdn.microsoft.com/en-us/library/cc237953.aspx
18type CredentialsInfo struct {
19	Version                    uint32 // A 32-bit unsigned integer in little-endian format that defines the version. MUST be 0x00000000.
20	EType                      uint32
21	PACCredentialDataEncrypted []byte // Key usage number for encryption: KERB_NON_KERB_SALT (16)
22	PACCredentialData          CredentialData
23}
24
25// Unmarshal bytes into the CredentialsInfo struct
26func (c *CredentialsInfo) Unmarshal(b []byte, k types.EncryptionKey) (err error) {
27	//The CredentialsInfo structure is a simple structure that is not NDR-encoded.
28	r := mstypes.NewReader(bytes.NewReader(b))
29
30	c.Version, err = r.Uint32()
31	if err != nil {
32		return
33	}
34	if c.Version != 0 {
35		err = errors.New("credentials info version is not zero")
36		return
37	}
38	c.EType, err = r.Uint32()
39	if err != nil {
40		return
41	}
42	c.PACCredentialDataEncrypted, err = r.ReadBytes(len(b) - 8)
43	if err != nil {
44		err = fmt.Errorf("error reading PAC Credetials Data: %v", err)
45		return
46	}
47
48	err = c.DecryptEncPart(k)
49	if err != nil {
50		err = fmt.Errorf("error decrypting PAC Credentials Data: %v", err)
51		return
52	}
53	return
54}
55
56// DecryptEncPart decrypts the encrypted part of the CredentialsInfo.
57func (c *CredentialsInfo) DecryptEncPart(k types.EncryptionKey) error {
58	if k.KeyType != int32(c.EType) {
59		return fmt.Errorf("key provided is not the correct type. Type needed: %d, type provided: %d", c.EType, k.KeyType)
60	}
61	pt, err := crypto.DecryptMessage(c.PACCredentialDataEncrypted, k, keyusage.KERB_NON_KERB_SALT)
62	if err != nil {
63		return err
64	}
65	err = c.PACCredentialData.Unmarshal(pt)
66	if err != nil {
67		return err
68	}
69	return nil
70}
71
72// CredentialData implements https://msdn.microsoft.com/en-us/library/cc237952.aspx
73type CredentialData struct {
74	CredentialCount uint32
75	Credentials     []SECPKGSupplementalCred // Size is the value of CredentialCount
76}
77
78// Unmarshal converts the bytes provided into a CredentialData type.
79func (c *CredentialData) Unmarshal(b []byte) (err error) {
80	dec := ndr.NewDecoder(bytes.NewReader(b))
81	err = dec.Decode(c)
82	if err != nil {
83		err = fmt.Errorf("error unmarshaling KerbValidationInfo: %v", err)
84	}
85	return
86}
87