Files
Go_I2p/lib/common/keys_and_cert.go
2021-07-29 18:01:01 -04:00

280 lines
9.1 KiB
Go

package common
/*
I2P KeysAndCert
https://geti2p.net/spec/common-structures#keysandcert
Accurate for version 0.9.24
+----+----+----+----+----+----+----+----+
| public_key |
+ +
| |
~ ~
~ ~
| |
+----+----+----+----+----+----+----+----+
| padding (optional) |
~ ~
~ ~
| |
+----+----+----+----+----+----+----+----+
| signing_key |
+ +
| |
~ ~
~ ~
| |
+----+----+----+----+----+----+----+----+
| certificate |
+----+----+----+-//
public_key :: PublicKey (partial or full)
length -> 256 bytes or as specified in key certificate
padding :: random data
length -> 0 bytes or as specified in key certificate
padding length + signing_key length == KEYS_AND_CERT_SPK_SIZE bytes
signing__key :: SigningPublicKey (partial or full)
length -> 128 bytes or as specified in key certificate
padding length + signing_key length == KEYS_AND_CERT_SPK_SIZE bytes
certificate :: Certificate
length -> >= 3 bytes
total length: 387+ bytes
*/
import (
"errors"
"github.com/go-i2p/go-i2p/lib/crypto"
log "github.com/sirupsen/logrus"
)
// Sizes of various KeysAndCert structures and requirements
const (
KEYS_AND_CERT_PUBKEY_SIZE = 256
KEYS_AND_CERT_SPK_SIZE = 128
KEYS_AND_CERT_MIN_SIZE = 387
KEYS_AND_CERT_DATA_SIZE = 384
)
type KeysAndCertInterface interface {
GetPublicKey() (key crypto.PublicKey, err error)
GetSigningPublicKey() (signing_public_key crypto.SigningPublicKey, err error)
GetCertificate() (cert Certificate, err error)
Bytes() (bytes []byte)
}
type KeysAndCert struct {
crypto.SigningPublicKey
crypto.PublicKey
CertificateInterface
}
func (keys_and_cert KeysAndCert) Bytes() (bytes []byte) { //, err error) {
pubkey, _ := keys_and_cert.GetPublicKey()
signpubkey, _ := keys_and_cert.GetSigningPublicKey()
elg_key := pubkey.(crypto.ElgPublicKey)
dsa_key := signpubkey.(crypto.DSAPublicKey)
bytes = append(bytes, dsa_key[:]...)
bytes = append(bytes, elg_key[:]...)
bytes = append(bytes, keys_and_cert.CertificateInterface.Cert()...)
return
}
//
// Return the PublicKey for this KeysAndCert, reading from the Key Certificate if it is present to
// determine correct lengths.
//
func (keys_and_cert KeysAndCert) GetPublicKey() (key crypto.PublicKey, err error) {
data := make([]byte, KEYS_AND_CERT_PUBKEY_SIZE)
if keys_and_cert.PublicKey == nil {
epk := crypto.ElgPublicKey{}
copy(data[:KEYS_AND_CERT_PUBKEY_SIZE], epk[:])
keys_and_cert.PublicKey = epk
err = errors.New("error parsing KeysAndCert: data is smaller than minimum valid size")
}
/*cert, err := keys_and_cert.GetCertificate()
if err != nil {
return
}
cert_len, err := cert.Length()
if err != nil {
return
}
if cert_len != 0 {*/
key = keys_and_cert.PublicKey
/*}*/
return
}
//
// Return the SigningPublicKey for this KeysAndCert, reading from the Key Certificate if it is present to
// determine correct lengths.
//
func (keys_and_cert KeysAndCert) GetSigningPublicKey() (signing_public_key crypto.SigningPublicKey, err error) {
if keys_and_cert.SigningPublicKey == nil {
keys_and_cert.SigningPublicKey = crypto.DSAPublicKey{}
err = errors.New("error parsing KeysAndCert: data is smaller than minimum valid size")
}
/*cert, err := keys_and_cert.GetCertificate()
if err != nil {
return
}
cert_len, err := cert.Length()
if err != nil {
return
}
if cert_len != 0 {*/
signing_public_key = keys_and_cert.SigningPublicKey
/*}*/
return
}
//
// Return the Certificate contained in the KeysAndCert and any errors encountered while parsing the
// KeysAndCert or Certificate.
//
func (keys_and_cert KeysAndCert) GetCertificate() (cert CertificateInterface, err error) {
data_len := len(keys_and_cert.Cert())
if data_len < CERT_MIN_SIZE {
log.WithFields(log.Fields{
"at": "ReadKeysAndCert",
"data_len": data_len,
"required_len": KEYS_AND_CERT_MIN_SIZE,
"reason": "not enough data",
}).Error("error parsing keys and cert")
err = errors.New("certificate parsing warning: certificate data is shorter than specified by length")
}
if data_len > CERT_MIN_SIZE {
log.WithFields(log.Fields{
"at": "ReadKeysAndCert",
"data_len": data_len,
"required_len": KEYS_AND_CERT_MIN_SIZE,
"reason": "too much data",
}).Error("error parsing keys and cert")
err = errors.New("certificate parsing warning: certificate data is longer than specified by length")
}
cert = keys_and_cert.CertificateInterface
return
}
func ReadKeys(data []byte, cert CertificateInterface) (spk crypto.SigningPublicKey, pk crypto.PublicKey, remainder []byte, err error) {
data_len := len(data)
if data_len < KEYS_AND_CERT_MIN_SIZE {
log.WithFields(log.Fields{
"at": "ReadKeysAndCert",
"data_len": data_len,
"required_len": KEYS_AND_CERT_MIN_SIZE,
"reason": "not enough data",
}).Error("error parsing keys and cert")
err = errors.New("error parsing KeysAndCert: data is smaller than minimum valid size")
return
}
if cert == nil {
// No Certificate is present, return the KEYS_AND_CERT_PUBKEY_SIZE byte
// PublicKey space as ElgPublicKey.
var elg_key crypto.ElgPublicKey
copy(data[:KEYS_AND_CERT_PUBKEY_SIZE], elg_key[:])
pk = elg_key
} else {
// A Certificate is present in this KeysAndCert
cert_type, cert_bytes, _ := cert.Type()
if cert_type == CERT_KEY {
// This KeysAndCert contains a Key Certificate, construct
// a PublicKey from the data in the KeysAndCert and
// any additional data in the Certificate.
cert_integer, _ := NewInteger(cert_bytes)
pk, err = KeyCertificate{PKType: cert_integer}.ConstructPublicKey(
data[:KEYS_AND_CERT_PUBKEY_SIZE],
)
} else {
// Key Certificate is not present, return the KEYS_AND_CERT_PUBKEY_SIZE byte
// PublicKey space as ElgPublicKey. No other Certificate
// types are currently in use.
var elg_key crypto.ElgPublicKey
copy(data[:KEYS_AND_CERT_PUBKEY_SIZE], elg_key[:])
pk = elg_key
log.WithFields(log.Fields{
"at": "(KeysAndCert) PublicKey",
"cert_type": cert_type,
}).Warn("unused certificate type observed")
}
// }
if data_len == 0 {
// No Certificate is present, return the KEYS_AND_CERT_SPK_SIZE byte
// SigningPublicKey space as legacy DSA SHA1 SigningPublicKey.
var dsa_pk crypto.DSAPublicKey
copy(dsa_pk[:], data[KEYS_AND_CERT_PUBKEY_SIZE:KEYS_AND_CERT_PUBKEY_SIZE+KEYS_AND_CERT_SPK_SIZE])
spk = dsa_pk
} else {
// A Certificate is present in this KeysAndCert
cert_type, cert_bytes, _ := cert.Type()
if cert_type == CERT_KEY {
// This KeysAndCert contains a Key Certificate, construct
// a SigningPublicKey from the data in the KeysAndCert and
// any additional data in the Certificate.
cert_integer, _ := NewInteger(cert_bytes)
spk, err = KeyCertificate{SPKType: cert_integer}.ConstructSigningPublicKey(
data[KEYS_AND_CERT_PUBKEY_SIZE : KEYS_AND_CERT_PUBKEY_SIZE+KEYS_AND_CERT_SPK_SIZE],
)
} else {
// Key Certificate is not present, return the KEYS_AND_CERT_SPK_SIZE byte
// SigningPublicKey space as legacy SHA DSA1 SigningPublicKey.
// No other Certificate types are currently in use.
var dsa_pk crypto.DSAPublicKey
copy(dsa_pk[:], data[KEYS_AND_CERT_PUBKEY_SIZE:KEYS_AND_CERT_PUBKEY_SIZE+KEYS_AND_CERT_SPK_SIZE])
spk = dsa_pk
}
}
cert_len, _ := cert.Length()
if cert_len == 0 {
remainder = data[KEYS_AND_CERT_MIN_SIZE:]
return
}
remainder = data[KEYS_AND_CERT_PUBKEY_SIZE+KEYS_AND_CERT_SPK_SIZE:]
}
return
}
//
// Read a KeysAndCert from a slice of bytes, retuning it and the remaining data as well as any errors
// encoutered parsing the KeysAndCert.
//
func ReadKeysAndCert(data []byte) (keys_and_cert KeysAndCert, remainder []byte, err error) {
data_len := len(data)
keys_and_cert.CertificateInterface = &Certificate{}
if data_len < KEYS_AND_CERT_MIN_SIZE {
log.WithFields(log.Fields{
"at": "ReadKeysAndCert",
"data_len": data_len,
"required_len": KEYS_AND_CERT_MIN_SIZE,
"reason": "not enough data",
}).Error("error parsing keys and cert")
err = errors.New("error parsing KeysAndCert: data is smaller than minimum valid size")
// return
}
cert, remainder, err := ReadCertificate(data[KEYS_AND_CERT_DATA_SIZE:])
if err != nil {
//return
log.Error("ERROR READ CERTIFICATE", err)
err = nil
}
log.Println("READ CERTIFICATE", cert.Cert())
keys_and_cert.CertificateInterface = cert
spk, pk, remainder, err := ReadKeys(data, cert)
if err != nil {
// return
log.Error("ERROR READ KEYS", err)
err = nil
}
log.Println("READ KEYS")
keys_and_cert.SigningPublicKey = spk
keys_and_cert.PublicKey = pk
return
}