Harden auth, add subtitles, vendor all assets locally

- Session cookies are HttpOnly + SameSite=Lax (Secure on HTTPS), with
  strict session-ID mode; the CSRF token from GET api/auth.php must now
  accompany every state-changing request (X-CSRF-Token header, or a csrf
  body field for the sendBeacon progress save), rotated at login.
- Failed sign-ins are throttled per username and IP via login_attempts
  (created lazily, so existing installs need no migration): 5 failures a
  username / 20 an IP inside 15 minutes answer 429 with Retry-After.
- A video's sibling .srt now appears as a CC button in the player;
  captions.php converts it to WebVTT (comma timestamps, legacy encodings,
  and the already-VTT files with out-of-spec 6-digit fractions).
- Plyr and Inter ship in assets/vendor/ instead of coming from CDNs, and
  anime.js is gone along with all scripted animations and the motion
  setting — the app now runs with no internet access at all.
- .htaccess denies direct access to videos/, includes/, config.php and
  schema.sql, so video URLs cannot bypass login on Apache.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SePf61iazhCLJBefdRLBDm
This commit is contained in:
Harwinder Sekhon
2026-07-30 21:14:07 -04:00
parent 0bd11f6ab3
commit 17a401c313
22 changed files with 433 additions and 102 deletions
+114
View File
@@ -2,6 +2,16 @@
require_once __DIR__ . '/db.php';
if (session_status() === PHP_SESSION_NONE) {
// Reject session IDs the server never issued (blocks session fixation),
// and keep the cookie away from scripts and cross-site requests.
ini_set('session.use_strict_mode', '1');
session_set_cookie_params([
'lifetime' => 0,
'path' => '/',
'secure' => !empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] !== 'off',
'httponly' => true,
'samesite' => 'Lax',
]);
session_start();
}
@@ -10,6 +20,33 @@ function currentUserId(): ?int
return isset($_SESSION['user_id']) ? (int)$_SESSION['user_id'] : null;
}
/* ---------------------------------------------------------------------------
* CSRF
* The token lives in the session and reaches the SPA via GET api/auth.php
* (and again in the login/register response, since login rotates it). Every
* state-changing request must echo it back — fetch() sends the X-CSRF-Token
* header; sendBeacon() can't set headers, so a `csrf` body field counts too.
* ------------------------------------------------------------------------- */
function csrfToken(): string
{
if (empty($_SESSION['csrf_token'])) {
$_SESSION['csrf_token'] = bin2hex(random_bytes(16));
}
return $_SESSION['csrf_token'];
}
/** 403s the request unless it carries the session's CSRF token. */
function verifyCsrfApi(?array $body = null): void
{
$sent = $_SERVER['HTTP_X_CSRF_TOKEN'] ?? $body['csrf'] ?? '';
if (!is_string($sent) || $sent === '' || !hash_equals(csrfToken(), $sent)) {
http_response_code(403);
header('Content-Type: application/json');
echo json_encode(['error' => 'Invalid session token — reload the page and try again.']);
exit;
}
}
function currentUsername(): ?string
{
return $_SESSION['username'] ?? null;
@@ -44,6 +81,7 @@ function attemptLogin(string $username, string $password): bool
$user = $stmt->fetch();
if ($user && password_verify($password, $user['password_hash'])) {
session_regenerate_id(true);
unset($_SESSION['csrf_token']); // a fresh token for the fresh session id
$_SESSION['user_id'] = (int)$user['id'];
$_SESSION['username'] = $user['username'];
return true;
@@ -51,6 +89,82 @@ function attemptLogin(string $username, string $password): bool
return false;
}
/* ---------------------------------------------------------------------------
* Login brute-force throttle
* Failed attempts are recorded per username + IP. Once a username collects
* LOGIN_MAX_USER_FAILS failures (or an IP LOGIN_MAX_IP_FAILS, across any
* usernames) inside LOGIN_FAIL_WINDOW, sign-in answers 429 until the window
* has passed since the last failure. Retrying while blocked never verifies a
* password, so it doesn't extend the block. A successful login clears the
* username's failures.
* ------------------------------------------------------------------------- */
const LOGIN_FAIL_WINDOW = 900; // seconds
const LOGIN_MAX_USER_FAILS = 5;
const LOGIN_MAX_IP_FAILS = 20;
/** Seconds until this username/IP may try again — 0 means go ahead. */
function loginRetryAfter(string $username, string $ip): int
{
// The clock math stays inside MySQL: TIMESTAMP values come back in the
// connection's time zone, so comparing them against PHP's clock would be
// off by the server's UTC offset.
$recent = function (string $col, string $value): array {
$stmt = db()->prepare(
"SELECT COUNT(*) AS fails,
COALESCE(TIMESTAMPDIFF(SECOND, NOW(),
MAX(attempted_at) + INTERVAL " . LOGIN_FAIL_WINDOW . " SECOND), 0) AS retry
FROM login_attempts
WHERE $col = ? AND attempted_at > NOW() - INTERVAL " . LOGIN_FAIL_WINDOW . " SECOND"
);
$stmt->execute([$value]);
return $stmt->fetch();
};
try {
$user = $recent('username', $username);
$byIp = $recent('ip', $ip);
} catch (Throwable $e) {
return 0; // table not created yet — no failures recorded so far
}
$retry = 0;
if ((int)$user['fails'] >= LOGIN_MAX_USER_FAILS) {
$retry = max($retry, (int)$user['retry']);
}
if ((int)$byIp['fails'] >= LOGIN_MAX_IP_FAILS) {
$retry = max($retry, (int)$byIp['retry']);
}
return max(0, $retry);
}
function recordLoginFailure(string $username, string $ip): void
{
$db = db();
// Lazy creation keeps installs made before this table existed working
// (same pattern as app_meta).
$db->exec(
'CREATE TABLE IF NOT EXISTS login_attempts (
id INT UNSIGNED AUTO_INCREMENT PRIMARY KEY,
username VARCHAR(50) NOT NULL,
ip VARCHAR(45) NOT NULL,
attempted_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
INDEX idx_la_user_time (username, attempted_at),
INDEX idx_la_ip_time (ip, attempted_at)
) ENGINE=InnoDB'
);
$db->prepare('DELETE FROM login_attempts WHERE attempted_at < NOW() - INTERVAL 1 HOUR')->execute();
$db->prepare('INSERT INTO login_attempts (username, ip) VALUES (?, ?)')->execute([$username, $ip]);
}
function clearLoginFailures(string $username): void
{
try {
db()->prepare('DELETE FROM login_attempts WHERE username = ?')->execute([$username]);
} catch (Throwable $e) {
// table doesn't exist yet — nothing to clear
}
}
/** Returns true on success, or an error-message string. */
function registerUser(string $username, string $password): string|bool
{
+56
View File
@@ -692,6 +692,62 @@ function quizFilePath(array $quiz): ?string
return $file;
}
/**
* Absolute, containment-checked path of a video's sibling subtitle file
* ("Lesson.mp4" -> "Lesson.srt"), or null if there isn't one.
*/
function srtFilePath(array $video): ?string
{
$rel = preg_replace('/\.mp4$/i', '.srt', $video['path']);
if ($rel === null || $rel === $video['path']) {
return null;
}
$file = realpath(rtrim(VIDEOS_ROOT, '/') . '/' . $rel);
$root = realpath(VIDEOS_ROOT);
if ($file === false || $root === false
|| !str_starts_with($file, $root . DIRECTORY_SEPARATOR) || !is_file($file)) {
return null;
}
return $file;
}
/**
* SubRip -> WebVTT (the only caption format browsers take in <track>).
* The formats differ by a header line and the decimal separator in
* timestamps; cue numbers are legal VTT cue identifiers and pass through.
*/
function srtToVtt(string $srt): string
{
if (str_starts_with($srt, "\xEF\xBB\xBF")) {
$srt = substr($srt, 3);
}
if (!preg_match('//u', $srt)) { // not valid UTF-8 — legacy single-byte file
$recoded = function_exists('iconv')
? @iconv('Windows-1252', 'UTF-8//TRANSLIT', $srt)
: (function_exists('mb_convert_encoding')
? mb_convert_encoding($srt, 'UTF-8', 'Windows-1252') : false);
if (is_string($recoded)) {
$srt = $recoded;
}
}
$srt = str_replace(["\r\n", "\r"], "\n", $srt);
// Normalise timestamps to HH:MM:SS.mmm. SRT uses a comma; generated files
// in the wild also carry single-digit hours and six-digit fractions, and
// the WebVTT parsing algorithm rejects any fraction that isn't exactly
// three digits — such cues would silently drop.
$srt = preg_replace_callback(
'/(\d+):(\d{2}):(\d{2})[.,](\d+)/',
fn($m) => sprintf('%02d:%s:%s.%s', $m[1], $m[2], $m[3],
substr(str_pad($m[4], 3, '0', STR_PAD_RIGHT), 0, 3)),
$srt
);
// Some ".srt" files are already WebVTT — don't stack a second header.
$srt = trim($srt);
return (str_starts_with($srt, 'WEBVTT') ? $srt : "WEBVTT\n\n" . $srt) . "\n";
}
/** Breadcrumb chain root -> ... -> folder. */
function folderBreadcrumbs(array $folder): array
{