Files
go-i2p/lib/common/keys_and_cert/keys_and_cert.go
2024-11-15 11:30:59 -05:00

253 lines
8.8 KiB
Go

// Package keys_and_cert implements the I2P KeysAndCert common data structure
package keys_and_cert
import (
"crypto/rand"
"errors"
"github.com/go-i2p/go-i2p/lib/util/logger"
. "github.com/go-i2p/go-i2p/lib/common/certificate"
. "github.com/go-i2p/go-i2p/lib/common/key_certificate"
"github.com/go-i2p/go-i2p/lib/crypto"
"github.com/sirupsen/logrus"
)
var log = logger.GetGoI2PLogger()
// 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
)
/*
[KeysAndCert]
Accurate for version 0.9.49
Description
An encryption public key, a signing public key, and a certificate, used as either a RouterIdentity or a Destination.
Contents
A publicKey followed by a signingPublicKey and then a Certificate.
+----+----+----+----+----+----+----+----+
| 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 == 128 bytes
signing__key :: signingPublicKey (partial or full)
length -> 128 bytes or as specified in key certificate
padding length + signing_key length == 128 bytes
certificate :: Certificate
length -> >= 3 bytes
total length: 387+ bytes
*/
// KeysAndCert is the represenation of an I2P KeysAndCert.
//
// https://geti2p.net/spec/common-structures#keysandcert
type KeysAndCert struct {
keyCertificate *KeyCertificate
publicKey crypto.PublicKey
Padding []byte
signingPublicKey crypto.SigningPublicKey
}
// Bytes returns the entire keyCertificate in []byte form, trims payload to specified length.
func (keys_and_cert KeysAndCert) Bytes() []byte {
bytes := keys_and_cert.publicKey.Bytes()
bytes = append(bytes, keys_and_cert.Padding...)
bytes = append(bytes, keys_and_cert.signingPublicKey.Bytes()...)
bytes = append(bytes, keys_and_cert.keyCertificate.Bytes()...)
log.WithFields(logrus.Fields{
"bytes_length": len(bytes),
"pk_bytes_length": len(keys_and_cert.publicKey.Bytes()),
"padding_bytes_length": len(keys_and_cert.Padding),
"spk_bytes_length": len(keys_and_cert.signingPublicKey.Bytes()),
"cert_bytes_length": len(keys_and_cert.keyCertificate.Bytes()),
}).Debug("Retrieved bytes from KeysAndCert")
return bytes
}
// publicKey returns the public key as a crypto.publicKey.
func (keys_and_cert *KeysAndCert) PublicKey() (key crypto.PublicKey) {
return keys_and_cert.publicKey
}
// signingPublicKey returns the signing public key.
func (keys_and_cert *KeysAndCert) SigningPublicKey() (signing_public_key crypto.SigningPublicKey) {
return keys_and_cert.signingPublicKey
}
// Certfificate returns the certificate.
func (keys_and_cert *KeysAndCert) Certificate() (cert Certificate) {
return keys_and_cert.keyCertificate.Certificate
}
// ReadKeysAndCert creates a new *KeysAndCert from []byte using ReadKeysAndCert.
// Returns a pointer to KeysAndCert unlike ReadKeysAndCert.
func ReadKeysAndCert(data []byte) (keys_and_cert KeysAndCert, remainder []byte, err error) {
log.WithFields(logrus.Fields{
"input_length": len(data),
}).Debug("Reading KeysAndCert from data")
data_len := len(data)
// keys_and_cert = KeysAndCert{}
if data_len < KEYS_AND_CERT_MIN_SIZE && data_len > KEYS_AND_CERT_DATA_SIZE {
log.WithFields(logrus.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")
keys_and_cert.keyCertificate, remainder, _ = NewKeyCertificate(data[KEYS_AND_CERT_DATA_SIZE:])
return
} else if data_len < KEYS_AND_CERT_DATA_SIZE {
log.WithFields(logrus.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
}
keys_and_cert.keyCertificate, remainder, err = NewKeyCertificate(data[KEYS_AND_CERT_DATA_SIZE:])
if err != nil {
log.WithError(err).Error("Failed to create keyCertificate")
return
}
// TODO: this only supports one key type right now and it's the old key type, but the layout is the same.
// a case-switch which sets the size of the SPK and the PK should be used to replace the referenced KEYS_AND_CERT_PUBKEY_SIZE
// and KEYS_AND_CERT_SPK_SIZE constants in the future.
keys_and_cert.publicKey, err = keys_and_cert.keyCertificate.ConstructPublicKey(data[:keys_and_cert.keyCertificate.CryptoSize()])
if err != nil {
log.WithError(err).Error("Failed to construct publicKey")
return
}
keys_and_cert.signingPublicKey, err = keys_and_cert.keyCertificate.ConstructSigningPublicKey(data[KEYS_AND_CERT_DATA_SIZE-keys_and_cert.keyCertificate.SignatureSize() : KEYS_AND_CERT_DATA_SIZE])
if err != nil {
log.WithError(err).Error("Failed to construct signingPublicKey")
return
}
padding := data[KEYS_AND_CERT_PUBKEY_SIZE : KEYS_AND_CERT_DATA_SIZE-KEYS_AND_CERT_SPK_SIZE]
keys_and_cert.Padding = padding
log.WithFields(logrus.Fields{
"public_key_type": keys_and_cert.keyCertificate.PublicKeyType(),
"signing_public_key_type": keys_and_cert.keyCertificate.SigningPublicKeyType(),
"padding_length": len(padding),
"remainder_length": len(remainder),
}).Debug("Successfully read KeysAndCert")
return
}
// NewKeysAndCert creates a new KeysAndCert instance with the provided parameters.
// It validates the sizes of the provided keys and padding before assembling the struct.
func NewKeysAndCert(
keyCertificate *KeyCertificate,
publicKey crypto.PublicKey,
padding []byte,
signingPublicKey crypto.SigningPublicKey,
) (*KeysAndCert, error) {
log.Debug("Creating new KeysAndCert with provided parameters")
// 1. Validate keyCertificate
if keyCertificate == nil {
log.Error("KeyCertificate is nil")
return nil, errors.New("KeyCertificate cannot be nil")
}
// 2. Validate publicKey size
if publicKey.Len() != KEYS_AND_CERT_PUBKEY_SIZE {
log.WithFields(logrus.Fields{
"expected_size": KEYS_AND_CERT_PUBKEY_SIZE,
"actual_size": publicKey.Len(),
}).Error("Invalid publicKey size")
return nil, errors.New("publicKey has an invalid size")
}
/*
// 3. Validate signingPublicKey size
if signingPublicKey.Len() != KEYS_AND_CERT_SPK_SIZE {
log.WithFields(logrus.Fields{
"expected_size": KEYS_AND_CERT_SPK_SIZE,
"actual_size": signingPublicKey.Len(),
}).Error("Invalid signingPublicKey size")
return nil, errors.New("signingPublicKey has an invalid size")
}
*/
// 4. Validate padding size
publicKeyLength := publicKey.Len()
signingPublicKeyLength := signingPublicKey.Len()
totalKeysSize := publicKeyLength + signingPublicKeyLength
expectedPaddingSize := KEYS_AND_CERT_DATA_SIZE - totalKeysSize
if len(padding) != expectedPaddingSize {
log.WithFields(logrus.Fields{
"expected_size": expectedPaddingSize,
"actual_size": len(padding),
}).Warn("Invalid padding size")
// generate some random padding and continue
padding = make([]byte, expectedPaddingSize)
_, err := rand.Read(padding)
if err != nil {
log.WithError(err).Error("Failed to generate random padding")
return nil, err
}
log.WithFields(logrus.Fields{
"expected_size": expectedPaddingSize,
"actual_size": len(padding),
}).Warn("Generated random padding")
}
// 5. Assemble KeysAndCert
keysAndCert := &KeysAndCert{
keyCertificate: keyCertificate,
publicKey: publicKey,
Padding: padding,
signingPublicKey: signingPublicKey,
}
log.WithFields(logrus.Fields{
"public_key_length": publicKey.Len(),
"signing_public_key_length": signingPublicKey.Len(),
"padding_length": len(padding),
}).Debug("Successfully created KeysAndCert")
return keysAndCert, nil
}