249 lines
8.2 KiB
Go
249 lines
8.2 KiB
Go
// Package keys_and_cert implements the I2P KeysAndCert common data structure
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package keys_and_cert
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import (
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"crypto/rand"
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"errors"
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"fmt"
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"github.com/go-i2p/go-i2p/lib/util/logger"
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. "github.com/go-i2p/go-i2p/lib/common/certificate"
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. "github.com/go-i2p/go-i2p/lib/common/key_certificate"
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"github.com/go-i2p/go-i2p/lib/crypto"
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"github.com/sirupsen/logrus"
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)
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var log = logger.GetGoI2PLogger()
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// Sizes of various KeysAndCert structures and requirements
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const (
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KEYS_AND_CERT_PUBKEY_SIZE = 256
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KEYS_AND_CERT_SPK_SIZE = 128
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KEYS_AND_CERT_MIN_SIZE = 387
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KEYS_AND_CERT_DATA_SIZE = 384
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)
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/*
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[KeysAndCert]
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Accurate for version 0.9.49
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Description
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An encryption public key, a signing public key, and a certificate, used as either a RouterIdentity or a Destination.
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Contents
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A publicKey followed by a signingPublicKey and then a Certificate.
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+----+----+----+----+----+----+----+----+
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| public_key |
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+ +
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| |
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~ ~
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~ ~
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| |
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+----+----+----+----+----+----+----+----+
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| padding (optional) |
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~ ~
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~ ~
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| |
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+----+----+----+----+----+----+----+----+
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| signing_key |
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+ +
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| |
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~ ~
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~ ~
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+----+----+----+----+----+----+----+----+
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| certificate |
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+----+----+----+-//
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public_key :: publicKey (partial or full)
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length -> 256 bytes or as specified in key certificate
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padding :: random data
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length -> 0 bytes or as specified in key certificate
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padding length + signing_key length == 128 bytes
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signing__key :: signingPublicKey (partial or full)
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length -> 128 bytes or as specified in key certificate
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padding length + signing_key length == 128 bytes
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certificate :: Certificate
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length -> >= 3 bytes
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total length: 387+ bytes
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*/
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// KeysAndCert is the represenation of an I2P KeysAndCert.
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//
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// https://geti2p.net/spec/common-structures#keysandcert
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type KeysAndCert struct {
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keyCertificate *KeyCertificate
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publicKey crypto.PublicKey
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Padding []byte
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signingPublicKey crypto.SigningPublicKey
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}
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// Bytes returns the entire keyCertificate in []byte form, trims payload to specified length.
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func (keys_and_cert KeysAndCert) Bytes() []byte {
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bytes := keys_and_cert.publicKey.Bytes()
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bytes = append(bytes, keys_and_cert.Padding...)
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bytes = append(bytes, keys_and_cert.signingPublicKey.Bytes()...)
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bytes = append(bytes, keys_and_cert.keyCertificate.Bytes()...)
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log.WithFields(logrus.Fields{
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"bytes_length": len(bytes),
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"pk_bytes_length": len(keys_and_cert.publicKey.Bytes()),
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"padding_bytes_length": len(keys_and_cert.Padding),
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"spk_bytes_length": len(keys_and_cert.signingPublicKey.Bytes()),
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"cert_bytes_length": len(keys_and_cert.keyCertificate.Bytes()),
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}).Debug("Retrieved bytes from KeysAndCert")
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return bytes
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}
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// publicKey returns the public key as a crypto.publicKey.
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func (keys_and_cert *KeysAndCert) PublicKey() (key crypto.PublicKey) {
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return keys_and_cert.publicKey
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}
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// signingPublicKey returns the signing public key.
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func (keys_and_cert *KeysAndCert) SigningPublicKey() (signing_public_key crypto.SigningPublicKey) {
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return keys_and_cert.signingPublicKey
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}
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// Certfificate returns the certificate.
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func (keys_and_cert *KeysAndCert) Certificate() (cert Certificate) {
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return keys_and_cert.keyCertificate.Certificate
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}
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// ReadKeysAndCert creates a new *KeysAndCert from []byte using ReadKeysAndCert.
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// Returns a pointer to KeysAndCert unlike ReadKeysAndCert.
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func ReadKeysAndCert(data []byte) (keys_and_cert KeysAndCert, remainder []byte, err error) {
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log.WithFields(logrus.Fields{
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"input_length": len(data),
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}).Debug("Reading KeysAndCert from data")
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data_len := len(data)
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if data_len < KEYS_AND_CERT_MIN_SIZE {
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log.WithFields(logrus.Fields{
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"at": "ReadKeysAndCert",
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"data_len": data_len,
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"required_len": KEYS_AND_CERT_MIN_SIZE,
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"reason": "not enough data",
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}).Error("error parsing keys and cert")
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err = errors.New("error parsing KeysAndCert: data is smaller than minimum valid size")
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return
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}
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keys_and_cert.keyCertificate, remainder, err = NewKeyCertificate(data[KEYS_AND_CERT_DATA_SIZE:])
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if err != nil {
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log.WithError(err).Error("Failed to create keyCertificate")
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return
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}
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// Get the actual key sizes from the certificate
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pubKeySize := keys_and_cert.keyCertificate.CryptoSize()
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sigKeySize := keys_and_cert.keyCertificate.SignatureSize()
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// Construct public key
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keys_and_cert.publicKey, err = keys_and_cert.keyCertificate.ConstructPublicKey(data[:pubKeySize])
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if err != nil {
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log.WithError(err).Error("Failed to construct publicKey")
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return
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}
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// Calculate padding size and extract padding
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paddingSize := KEYS_AND_CERT_DATA_SIZE - pubKeySize - sigKeySize
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if paddingSize > 0 {
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keys_and_cert.Padding = make([]byte, paddingSize)
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copy(keys_and_cert.Padding, data[pubKeySize:pubKeySize+paddingSize])
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}
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// Construct signing public key
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keys_and_cert.signingPublicKey, err = keys_and_cert.keyCertificate.ConstructSigningPublicKey(
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data[KEYS_AND_CERT_DATA_SIZE-sigKeySize : KEYS_AND_CERT_DATA_SIZE],
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)
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if err != nil {
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log.WithError(err).Error("Failed to construct signingPublicKey")
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return
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}
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log.WithFields(logrus.Fields{
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"public_key_type": keys_and_cert.keyCertificate.PublicKeyType(),
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"signing_public_key_type": keys_and_cert.keyCertificate.SigningPublicKeyType(),
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"padding_length": len(keys_and_cert.Padding),
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"remainder_length": len(remainder),
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}).Debug("Successfully read KeysAndCert")
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return
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}
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// NewKeysAndCert creates a new KeysAndCert instance with the provided parameters.
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// It validates the sizes of the provided keys and padding before assembling the struct.
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func NewKeysAndCert(
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keyCertificate *KeyCertificate,
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publicKey crypto.PublicKey,
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padding []byte,
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signingPublicKey crypto.SigningPublicKey,
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) (*KeysAndCert, error) {
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log.Debug("Creating new KeysAndCert with provided parameters")
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if keyCertificate == nil {
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log.Error("KeyCertificate is nil")
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return nil, errors.New("KeyCertificate cannot be nil")
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}
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// Get actual key sizes from certificate
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pubKeySize := keyCertificate.CryptoSize()
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sigKeySize := keyCertificate.SignatureSize()
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// Validate public key size
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if publicKey.Len() != pubKeySize {
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log.WithFields(logrus.Fields{
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"expected_size": pubKeySize,
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"actual_size": publicKey.Len(),
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}).Error("Invalid publicKey size")
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return nil, fmt.Errorf("publicKey has invalid size: expected %d, got %d", pubKeySize, publicKey.Len())
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}
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// Validate signing key size
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if signingPublicKey.Len() != sigKeySize {
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log.WithFields(logrus.Fields{
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"expected_size": sigKeySize,
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"actual_size": signingPublicKey.Len(),
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}).Error("Invalid signingPublicKey size")
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return nil, fmt.Errorf("signingPublicKey has invalid size: expected %d, got %d", sigKeySize, signingPublicKey.Len())
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}
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// Calculate expected padding size
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expectedPaddingSize := KEYS_AND_CERT_DATA_SIZE - pubKeySize - sigKeySize
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if len(padding) != expectedPaddingSize {
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log.WithFields(logrus.Fields{
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"expected_size": expectedPaddingSize,
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"actual_size": len(padding),
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}).Warn("Invalid padding size")
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// Generate random padding if invalid or missing
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padding = make([]byte, expectedPaddingSize)
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if _, err := rand.Read(padding); err != nil {
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log.WithError(err).Error("Failed to generate random padding")
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return nil, err
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}
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log.Debug("Generated random padding")
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}
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keysAndCert := &KeysAndCert{
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keyCertificate: keyCertificate,
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publicKey: publicKey,
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Padding: padding,
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signingPublicKey: signingPublicKey,
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}
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log.WithFields(logrus.Fields{
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"public_key_length": publicKey.Len(),
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"signing_public_key_length": signingPublicKey.Len(),
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"padding_length": len(padding),
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}).Debug("Successfully created KeysAndCert")
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return keysAndCert, nil
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}
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