| 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 |
| } |