telebit/vendor/github.com/jcmturner/gokrb5/v8/pac/signature_data.go

68 lines
2.1 KiB
Go

package pac
import (
"bytes"
"github.com/jcmturner/gokrb5/v8/iana/chksumtype"
"github.com/jcmturner/rpc/v2/mstypes"
)
/*
https://msdn.microsoft.com/en-us/library/cc237955.aspx
The Key Usage Value MUST be KERB_NON_KERB_CKSUM_SALT (17) [MS-KILE] (section 3.1.5.9).
Server Signature (SignatureType = 0x00000006)
https://msdn.microsoft.com/en-us/library/cc237957.aspx
KDC Signature (SignatureType = 0x00000007)
https://msdn.microsoft.com/en-us/library/dd357117.aspx
*/
// SignatureData implements https://msdn.microsoft.com/en-us/library/cc237955.aspx
type SignatureData struct {
SignatureType uint32 // A 32-bit unsigned integer value in little-endian format that defines the cryptographic system used to calculate the checksum. This MUST be one of the following checksum types: KERB_CHECKSUM_HMAC_MD5 (signature size = 16), HMAC_SHA1_96_AES128 (signature size = 12), HMAC_SHA1_96_AES256 (signature size = 12).
Signature []byte // Size depends on the type. See comment above.
RODCIdentifier uint16 // A 16-bit unsigned integer value in little-endian format that contains the first 16 bits of the key version number ([MS-KILE] section 3.1.5.8) when the KDC is an RODC. When the KDC is not an RODC, this field does not exist.
}
// Unmarshal bytes into the SignatureData struct
func (k *SignatureData) Unmarshal(b []byte) (rb []byte, err error) {
r := mstypes.NewReader(bytes.NewReader(b))
k.SignatureType, err = r.Uint32()
if err != nil {
return
}
var c int
switch k.SignatureType {
case chksumtype.KERB_CHECKSUM_HMAC_MD5_UNSIGNED:
c = 16
case uint32(chksumtype.HMAC_SHA1_96_AES128):
c = 12
case uint32(chksumtype.HMAC_SHA1_96_AES256):
c = 12
}
k.Signature, err = r.ReadBytes(c)
if err != nil {
return
}
// When the KDC is not an Read Only Domain Controller (RODC), this field does not exist.
if len(b) >= 4+c+2 {
k.RODCIdentifier, err = r.Uint16()
if err != nil {
return
}
}
// Create bytes with zeroed signature needed for checksum verification
rb = make([]byte, len(b), len(b))
copy(rb, b)
z := make([]byte, len(b), len(b))
copy(rb[4:4+c], z)
return
}