package pac import ( "bytes" "errors" "fmt" "github.com/jcmturner/gokrb5/v8/crypto" "github.com/jcmturner/gokrb5/v8/iana/keyusage" "github.com/jcmturner/gokrb5/v8/types" "github.com/jcmturner/rpc/v2/mstypes" "github.com/jcmturner/rpc/v2/ndr" ) // https://msdn.microsoft.com/en-us/library/cc237931.aspx // CredentialsInfo implements https://msdn.microsoft.com/en-us/library/cc237953.aspx type CredentialsInfo struct { Version uint32 // A 32-bit unsigned integer in little-endian format that defines the version. MUST be 0x00000000. EType uint32 PACCredentialDataEncrypted []byte // Key usage number for encryption: KERB_NON_KERB_SALT (16) PACCredentialData CredentialData } // Unmarshal bytes into the CredentialsInfo struct func (c *CredentialsInfo) Unmarshal(b []byte, k types.EncryptionKey) (err error) { //The CredentialsInfo structure is a simple structure that is not NDR-encoded. r := mstypes.NewReader(bytes.NewReader(b)) c.Version, err = r.Uint32() if err != nil { return } if c.Version != 0 { err = errors.New("credentials info version is not zero") return } c.EType, err = r.Uint32() if err != nil { return } c.PACCredentialDataEncrypted, err = r.ReadBytes(len(b) - 8) err = c.DecryptEncPart(k) if err != nil { err = fmt.Errorf("error decrypting PAC Credentials Data: %v", err) return } return } // DecryptEncPart decrypts the encrypted part of the CredentialsInfo. func (c *CredentialsInfo) DecryptEncPart(k types.EncryptionKey) error { if k.KeyType != int32(c.EType) { return fmt.Errorf("key provided is not the correct type. Type needed: %d, type provided: %d", c.EType, k.KeyType) } pt, err := crypto.DecryptMessage(c.PACCredentialDataEncrypted, k, keyusage.KERB_NON_KERB_SALT) if err != nil { return err } err = c.PACCredentialData.Unmarshal(pt) if err != nil { return err } return nil } // CredentialData implements https://msdn.microsoft.com/en-us/library/cc237952.aspx type CredentialData struct { CredentialCount uint32 Credentials []SECPKGSupplementalCred // Size is the value of CredentialCount } // Unmarshal converts the bytes provided into a CredentialData type. func (c *CredentialData) Unmarshal(b []byte) (err error) { dec := ndr.NewDecoder(bytes.NewReader(b)) err = dec.Decode(c) if err != nil { err = fmt.Errorf("error unmarshaling KerbValidationInfo: %v", err) } return }