<?php
/*************************************************************
# 076 License

Copyright (c) テクニカル諏訪子

Permission is hereby granted to any person obtaining a copy of the software
Little Beast (the "Software") to use, modify, merge, copy, publish, distribute,
sublicense, and/or sell copies of the Software, subject to the following conditions:

    1. **Origin Attribution**:
       - You must not misrepresent the origin of the Software; you must not claim
         you created the original Software.
       - If the Software is used in a product, you must either:
         a. Provide clear attribution in the product's documentation, user interface,
            or other visible areas, **OR**
         b. Pay the original developers a fee they specify in writing.
    2. **Usage Restriction**:
       - The Software, or any derivative works, dependencies, or libraries
         incorporating it, must not be used for censorship or to suppress freedom of
         speech, expression, or creativity. Prohibited uses include, but are not
         limited to:
         - Censorship of so-called "hate speech", visuals, non-mainstream opinions,
           ideas, or objective reality.
         - Tools or systems designed to restrict access to information or
           artistic works.
    3. **Notice Preservation**:
       - This license and the above copyright notice must remain intact in all copies
         of the source code.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE
OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
// テスト用のTLS 1.3のサーバー（MockServerが起動する、Std\Lib\Tlsのサーバー側を使う）
// 使い方：php tls-server.php ポート 証明書のPEMファイル 秘密鍵のPEMファイル [ALPN（カンマ区切り）] [グループ（カンマ区切り）] [悪意] [最大のバージョン]
// 悪意：bad-finished（間違ったFinishedを送る）、bad-cv（間違ったCertificateVerify・ServerKeyExchangeの署名を送る）、
//       downgrade（クライアントのTLS 1.3を無視して1.2にする＝攻撃者がClientHelloを書き換えた場合）
// 受け取った行をそのまま返す。特別な行：
//   INFO        接続の情報（JSON）
//   KEYUPDATE   鍵を更新して（相手にも求める）「updated」
//   BIG n       nバイトを返す
//   CLOSE       close_notifyを送って閉じる
//   DROP        close_notifyを送らずに切る
//   GARBAGE     壊れた（復号出来ない）レコードを送る
//   HELLOREQ    TLS 1.2の再ネゴシエーションを求める（HelloRequest）、その後「asked」

require_once __DIR__.'/../../../../autoload.php';

use Std\Lib\Crypto\Ec;
use Std\Lib\Crypto\Rsa;
use Std\Lib\Tls;
use Std\Lib\Tls\Connection;
use Std\Lib\Tls\Stream;

/** クライアントの確認をテストする為の、間違ったメッセージを送るサーバー */
class EvilConnection extends Connection {
  private int $finishedCalls = 0;

  public function __construct($sock, array $opt, private string $mode) {
    parent::__construct($sock, $opt, true);
  }

  protected function finished(string $base): string {
    $f = parent::finished($base);
    // サーバーは最初に自分のFinishedを作る
    return $this->mode === 'bad-finished' && $this->finishedCalls++ === 0 ? ~$f : $f;
  }

  protected function finished12(string $master, string $label): string {
    $f = parent::finished12($master, $label);
    return $this->mode === 'bad-finished' && $label === 'server finished' ? ~$f : $f;
  }

  protected function signTranscript(Rsa|Ec $key, int $scheme, string $context): string {
    $sig = parent::signTranscript($key, $scheme, $context);
    return $this->mode === 'bad-cv' ? $key->sign('別のメッセージ', 'sha256') : $sig;
  }

  protected function signKeyExchange(Rsa|Ec $key, int $scheme, string $data): string {
    $sig = parent::signKeyExchange($key, $scheme, $data);
    return $this->mode === 'bad-cv' ? $key->sign('別のメッセージ', 'sha256') : $sig;
  }

  protected function parseClientHello(string $b): array {
    $ch = parent::parseClientHello($b);
    if ($this->mode === 'downgrade') $ch['versions'] = array_values(array_diff($ch['versions'], [0x0304]));
    return $ch;
  }

  /** TLS 1.2の再ネゴシエーションを求める */
  public function helloRequest(): void {
    $this->writeRecord(22, "\x00\x00\x00\x00");
  }
}

$port = (int)($argv[1] ?? 0);
$opt = ['cert' => $argv[2] ?? '', 'key' => $argv[3] ?? ''];
if (!empty($argv[4])) $opt['alpn'] = explode(',', $argv[4]);
if (!empty($argv[5])) $opt['groups'] = explode(',', $argv[5]);
$evil = $argv[6] ?? '';
if (!empty($argv[7])) $opt['max_version'] = $argv[7];

$server = @stream_socket_server("tcp://127.0.0.1:{$port}", $errno, $errstr);
if (!$server) {
  fwrite(STDOUT, "error {$errstr}\n");
  exit(1);
}
fwrite(STDOUT, "ready\n");
fflush(STDOUT);

while (true) {
  $c = @stream_socket_accept($server, 120);
  if (!$c) break;
  stream_set_timeout($c, 10);
  // MockServer::stop()の終了のリクエスト（暗号化されていない）
  $peek = stream_socket_recvfrom($c, 4, STREAM_PEEK);
  if ($peek === 'QUIT') break;

  try {
    $conn = new EvilConnection($c, $opt, $evil);
    $conn->handshake();
    $s = Stream::wrap($conn);
  } catch (\Throwable $e) {
    fwrite(STDERR, $e->getMessage()."\n");
    @fclose($c);
    continue;
  }

  while (($line = fgets($s)) !== false) {
    $cmd = rtrim($line, "\r\n");
    if ($cmd === 'INFO') {
      $i = Tls::info($s);
      unset($i['peer_certificates']);
      fwrite($s, json_encode($i)."\n");
    } else if ($cmd === 'KEYUPDATE') {
      Stream::connection($s)->keyUpdate(true);
      fwrite($s, "updated\n");
    } else if (str_starts_with($cmd, 'BIG ')) {
      fwrite($s, str_repeat('x', (int)substr($cmd, 4)));
    } else if ($cmd === 'CLOSE') {
      break;
    } else if ($cmd === 'HELLOREQ') {
      $conn->helloRequest();
      fwrite($s, "asked\n");
    } else if ($cmd === 'GARBAGE') {
      fwrite(Stream::connection($s)->socket(), "\x17\x03\x03\x00\x20".random_bytes(32));
    } else if ($cmd === 'DROP') {
      fclose(Stream::connection($s)->socket());
      continue 2;
    } else {
      fwrite($s, $line);
    }
  }
  fclose($s);
}