Extract more general-purpose logic to JwtUtils

this code could now be reused for creating custom login packets.
This commit is contained in:
Dylan K. Taylor 2020-05-13 20:46:01 +01:00
parent 161ac468f3
commit d7eb4f9651
3 changed files with 89 additions and 53 deletions

View File

@ -23,17 +23,39 @@ declare(strict_types=1);
namespace pocketmine\network\mcpe;
use Mdanter\Ecc\Crypto\Key\PrivateKeyInterface;
use Mdanter\Ecc\Crypto\Key\PublicKeyInterface;
use Mdanter\Ecc\Crypto\Signature\Signature;
use Mdanter\Ecc\Serializer\PrivateKey\DerPrivateKeySerializer;
use Mdanter\Ecc\Serializer\PrivateKey\PemPrivateKeySerializer;
use Mdanter\Ecc\Serializer\PublicKey\DerPublicKeySerializer;
use Mdanter\Ecc\Serializer\PublicKey\PemPublicKeySerializer;
use Mdanter\Ecc\Serializer\Signature\DerSignatureSerializer;
use pocketmine\network\mcpe\auth\VerifyLoginException;
use pocketmine\utils\AssumptionFailedError;
use function base64_decode;
use function base64_encode;
use function bin2hex;
use function count;
use function explode;
use function gmp_init;
use function gmp_strval;
use function hex2bin;
use function is_array;
use function json_decode;
use function json_encode;
use function json_last_error_msg;
use function openssl_error_string;
use function openssl_sign;
use function openssl_verify;
use function rtrim;
use function str_pad;
use function str_repeat;
use function str_split;
use function strlen;
use function strtr;
use const OPENSSL_ALGO_SHA384;
use const STR_PAD_LEFT;
final class JwtUtils{
@ -62,6 +84,57 @@ final class JwtUtils{
return [$header, $body, $signature];
}
/**
* @throws \UnexpectedValueException
*/
public static function verify(string $jwt, PublicKeyInterface $signingKey) : bool{
$parts = explode('.', $jwt);
if(count($parts) !== 3){
throw new \UnexpectedValueException("Expected exactly 3 JWT parts, got " . count($parts));
}
[$header, $body, $signature] = $parts;
$plainSignature = self::b64UrlDecode($signature);
if(strlen($plainSignature) !== 96){
throw new VerifyLoginException("JWT signature has unexpected length, expected 96, got " . strlen($plainSignature));
}
[$rString, $sString] = str_split($plainSignature, 48);
$sig = new Signature(gmp_init(bin2hex($rString), 16), gmp_init(bin2hex($sString), 16));
$v = openssl_verify(
$header . '.' . $body,
(new DerSignatureSerializer())->serialize($sig),
(new PemPublicKeySerializer(new DerPublicKeySerializer()))->serialize($signingKey),
OPENSSL_ALGO_SHA384
);
switch($v){
case 0: return false;
case 1: return true;
case -1: throw new \UnexpectedValueException("Error verifying JWT signature: " . openssl_error_string());
default: throw new AssumptionFailedError("openssl_verify() should only return -1, 0 or 1");
}
}
public static function create(array $header, array $claims, PrivateKeyInterface $signingKey) : string{
$jwtBody = JwtUtils::b64UrlEncode(json_encode($header)) . "." . JwtUtils::b64UrlEncode(json_encode($claims));
openssl_sign(
$jwtBody,
$sig,
(new PemPrivateKeySerializer(new DerPrivateKeySerializer()))->serialize($signingKey),
OPENSSL_ALGO_SHA384
);
$decodedSig = (new DerSignatureSerializer())->parse($sig);
$jwtSig = JwtUtils::b64UrlEncode(
hex2bin(str_pad(gmp_strval($decodedSig->getR(), 16), 96, "0", STR_PAD_LEFT)) .
hex2bin(str_pad(gmp_strval($decodedSig->getS(), 16), 96, "0", STR_PAD_LEFT))
);
return "$jwtBody.$jwtSig";
}
public static function b64UrlEncode(string $str) : string{
return rtrim(strtr(base64_encode($str), '+/', '-_'), '=');
}

View File

@ -25,24 +25,12 @@ namespace pocketmine\network\mcpe\auth;
use FG\ASN1\Exception\ParserException;
use Mdanter\Ecc\Crypto\Key\PublicKeyInterface;
use Mdanter\Ecc\Crypto\Signature\Signature;
use Mdanter\Ecc\Serializer\PublicKey\DerPublicKeySerializer;
use Mdanter\Ecc\Serializer\PublicKey\PemPublicKeySerializer;
use Mdanter\Ecc\Serializer\Signature\DerSignatureSerializer;
use pocketmine\network\mcpe\JwtUtils;
use pocketmine\network\mcpe\protocol\LoginPacket;
use pocketmine\scheduler\AsyncTask;
use pocketmine\utils\AssumptionFailedError;
use function base64_decode;
use function bin2hex;
use function count;
use function explode;
use function gmp_init;
use function openssl_verify;
use function str_split;
use function strlen;
use function time;
use const OPENSSL_ALGO_SHA384;
class ProcessLoginTask extends AsyncTask{
private const TLS_KEY_ON_COMPLETION = "completion";
@ -117,7 +105,7 @@ class ProcessLoginTask extends AsyncTask{
*/
private function validateToken(string $jwt, ?string &$currentPublicKey, bool $first = false) : void{
try{
[$headers, $claims, $plainSignature] = JwtUtils::parse($jwt);
[$headers, $claims, ] = JwtUtils::parse($jwt);
}catch(\UnexpectedValueException $e){
throw new VerifyLoginException("Failed to parse JWT: " . $e->getMessage(), 0, $e);
}
@ -131,13 +119,6 @@ class ProcessLoginTask extends AsyncTask{
$currentPublicKey = $headers["x5u"];
}
if(strlen($plainSignature) !== 96){
throw new VerifyLoginException("JWT signature has unexpected length, expected 96, got " . strlen($plainSignature));
}
[$rString, $sString] = str_split($plainSignature, 48);
$sig = new Signature(gmp_init(bin2hex($rString), 16), gmp_init(bin2hex($sString), 16));
$derPublicKeySerializer = new DerPublicKeySerializer();
$rawPublicKey = base64_decode($currentPublicKey, true);
if($rawPublicKey === false){
@ -149,17 +130,12 @@ class ProcessLoginTask extends AsyncTask{
throw new VerifyLoginException("Failed to parse DER public key: " . $e->getMessage(), 0, $e);
}
$rawParts = explode('.', $jwt);
if(count($rawParts) !== 3) throw new AssumptionFailedError("Parts count should be 3 as verified by JwtUtils::parse()");
$v = openssl_verify(
$rawParts[0] . '.' . $rawParts[1],
(new DerSignatureSerializer())->serialize($sig),
(new PemPublicKeySerializer($derPublicKeySerializer))->serialize($signingKey),
OPENSSL_ALGO_SHA384
);
if($v !== 1){
throw new VerifyLoginException("%pocketmine.disconnect.invalidSession.badSignature");
try{
if(!JwtUtils::verify($jwt, $signingKey)){
throw new VerifyLoginException("%pocketmine.disconnect.invalidSession.badSignature");
}
}catch(\UnexpectedValueException $e){
throw new VerifyLoginException($e->getMessage(), 0, $e);
}
if($currentPublicKey === self::MOJANG_ROOT_PUBLIC_KEY){

View File

@ -25,17 +25,12 @@ namespace pocketmine\network\mcpe\encryption;
use Mdanter\Ecc\Crypto\Key\PrivateKeyInterface;
use Mdanter\Ecc\Crypto\Key\PublicKeyInterface;
use Mdanter\Ecc\Serializer\PrivateKey\DerPrivateKeySerializer;
use Mdanter\Ecc\Serializer\PrivateKey\PemPrivateKeySerializer;
use Mdanter\Ecc\Serializer\PublicKey\DerPublicKeySerializer;
use Mdanter\Ecc\Serializer\Signature\DerSignatureSerializer;
use pocketmine\network\mcpe\JwtUtils;
use function base64_encode;
use function gmp_strval;
use function hex2bin;
use function json_encode;
use function openssl_digest;
use function openssl_sign;
use function str_pad;
final class EncryptionUtils{
@ -53,23 +48,15 @@ final class EncryptionUtils{
}
public static function generateServerHandshakeJwt(PrivateKeyInterface $serverPriv, string $salt) : string{
$jwtBody = JwtUtils::b64UrlEncode(json_encode([
"x5u" => base64_encode((new DerPublicKeySerializer())->serialize($serverPriv->getPublicKey())),
"alg" => "ES384"
])
) . "." . JwtUtils::b64UrlEncode(json_encode([
"salt" => base64_encode($salt)
])
);
openssl_sign($jwtBody, $sig, (new PemPrivateKeySerializer(new DerPrivateKeySerializer()))->serialize($serverPriv), OPENSSL_ALGO_SHA384);
$decodedSig = (new DerSignatureSerializer())->parse($sig);
$jwtSig = JwtUtils::b64UrlEncode(
hex2bin(str_pad(gmp_strval($decodedSig->getR(), 16), 96, "0", STR_PAD_LEFT)) .
hex2bin(str_pad(gmp_strval($decodedSig->getS(), 16), 96, "0", STR_PAD_LEFT))
return JwtUtils::create(
[
"x5u" => base64_encode((new DerPublicKeySerializer())->serialize($serverPriv->getPublicKey())),
"alg" => "ES384"
],
[
"salt" => base64_encode($salt)
],
$serverPriv
);
return "$jwtBody.$jwtSig";
}
}