julienmonnerie/kirby/src/Session/Session.php
2025-04-21 18:57:21 +02:00

810 lines
22 KiB
PHP

<?php
namespace Kirby\Session;
use Kirby\Exception\BadMethodCallException;
use Kirby\Exception\Exception;
use Kirby\Exception\InvalidArgumentException;
use Kirby\Exception\LogicException;
use Kirby\Exception\NotFoundException;
use Kirby\Http\Cookie;
use Kirby\Http\Url;
use Kirby\Toolkit\Str;
use Kirby\Toolkit\SymmetricCrypto;
/**
* @package Kirby Session
* @author Lukas Bestle <lukas@getkirby.com>
* @link https://getkirby.com
* @copyright Bastian Allgeier
* @license https://opensource.org/licenses/MIT
*/
class Session
{
// parent data
protected Sessions $sessions;
protected string $mode;
// parts of the token
protected int|null $tokenExpiry = null;
protected string|null $tokenId = null;
protected string|null $tokenKey = null;
// persistent data
protected int $startTime;
protected int $expiryTime;
protected int $duration;
protected int|false $timeout = false;
protected int|null $lastActivity = null;
protected bool $renewable;
protected SessionData $data;
protected array|null $newSession = null;
// temporary state flags
protected bool $updatingLastActivity = false;
protected bool $destroyed = false;
protected bool $writeMode = false;
protected bool $needsRetransmission = false;
/**
* Creates a new Session instance
*
* @param \Kirby\Session\Sessions $sessions Parent sessions object
* @param string|null $token Session token or null for a new session
* @param array $options Optional additional options:
* - `mode`: Token transmission mode (cookie or manual); defaults to `cookie`
* - `startTime`: Time the session starts being valid (date string or timestamp); defaults to `now`
* - `expiryTime`: Time the session expires (date string or timestamp); defaults to `+ 2 hours`
* - `timeout`: Activity timeout in seconds (integer or false for none); defaults to `1800` (half an hour)
* - `renewable`: Should it be possible to extend the expiry date?; defaults to `true`
*/
public function __construct(
Sessions $sessions,
string|null $token,
array $options
) {
$this->sessions = $sessions;
$this->mode = $options['mode'] ?? 'cookie';
// ensure that all changes are committed on script termination
register_shutdown_function([$this, 'commit']);
if (is_string($token) === true) {
// existing session
// set the token as instance vars
$this->parseToken($token);
// initialize, but only try to write to the session if not read-only
// (only the case for moved sessions)
$this->init();
if ($this->tokenKey !== null) {
$this->autoRenew();
}
return;
}
// new session ($token = null)
// set data based on options
$this->startTime = static::timeToTimestamp($options['startTime'] ?? time());
$this->expiryTime = static::timeToTimestamp($options['expiryTime'] ?? '+ 2 hours', $this->startTime);
$this->duration = $this->expiryTime - $this->startTime;
$this->timeout = $options['timeout'] ?? 1800;
$this->renewable = $options['renewable'] ?? true;
$this->data = new SessionData($this, []);
// validate persistent data
if (time() > $this->expiryTime) {
// session must not already be expired, but the start time may be in the future
throw new InvalidArgumentException([
'data' => [
'method' => 'Session::__construct',
'argument' => '$options[\'expiryTime\']'
],
'translate' => false
]);
}
if ($this->duration < 0) {
// expiry time must be after start time
throw new InvalidArgumentException([
'data' => [
'method' => 'Session::__construct',
'argument' => '$options[\'startTime\' & \'expiryTime\']'
],
'translate' => false
]);
}
// set activity time if a timeout was requested
if (is_int($this->timeout) === true) {
$this->lastActivity = time();
}
}
/**
* Gets the session token or null if the session doesn't have a token yet
*/
public function token(): string|null
{
if ($this->tokenExpiry !== null) {
$token = $this->tokenExpiry . '.' . $this->tokenId;
if (is_string($this->tokenKey) === true) {
$token .= '.' . $this->tokenKey;
}
return $token;
}
return null;
}
/**
* Gets or sets the transmission mode
* Setting only works for new sessions that haven't been transmitted yet
*
* @param string|null $mode Optional new transmission mode
* @return string Transmission mode
*/
public function mode(string|null $mode = null): string
{
if ($mode !== null) {
// only allow this if this is a new session, otherwise the change
// might not be applied correctly to the current request
if ($this->token() !== null) {
throw new InvalidArgumentException([
'data' => ['method' => 'Session::mode', 'argument' => '$mode'],
'translate' => false
]);
}
$this->mode = $mode;
}
return $this->mode;
}
/**
* Gets the session start time
*
* @return int Timestamp
*/
public function startTime(): int
{
return $this->startTime;
}
/**
* Gets or sets the session expiry time
* Setting the expiry time also updates the duration and regenerates the session token
*
* @param string|int|null $expiryTime Optional new expiry timestamp or time string to set
* @return int Timestamp
*/
public function expiryTime(string|int|null $expiryTime = null): int
{
if ($expiryTime !== null) {
// convert to a timestamp
$expiryTime = static::timeToTimestamp($expiryTime);
// verify that the expiry time is not in the past
if ($expiryTime <= time()) {
throw new InvalidArgumentException([
'data' => ['method' => 'Session::expiryTime', 'argument' => '$expiryTime'],
'translate' => false
]);
}
$this->prepareForWriting();
$this->expiryTime = $expiryTime;
$this->duration = $expiryTime - time();
$this->regenerateTokenIfNotNew();
}
return $this->expiryTime;
}
/**
* Gets or sets the session duration
* Setting the duration also updates the expiry time and regenerates the session token
*
* @param int|null $duration Optional new duration in seconds to set
* @return int Number of seconds
*/
public function duration(int|null $duration = null): int
{
if ($duration !== null) {
// verify that the duration is at least 1 second
if ($duration < 1) {
throw new InvalidArgumentException([
'data' => ['method' => 'Session::duration', 'argument' => '$duration'],
'translate' => false
]);
}
$this->prepareForWriting();
$this->duration = $duration;
$this->expiryTime = time() + $duration;
$this->regenerateTokenIfNotNew();
}
return $this->duration;
}
/**
* Gets or sets the session timeout
*
* @param int|false|null $timeout Optional new timeout to set or false to disable timeout
* @return int|false Number of seconds or false for "no timeout"
*/
public function timeout(int|false|null $timeout = null): int|false
{
if ($timeout !== null) {
// verify that the timeout is at least 1 second
if (is_int($timeout) === true && $timeout < 1) {
throw new InvalidArgumentException([
'data' => ['method' => 'Session::timeout', 'argument' => '$timeout'],
'translate' => false
]);
}
$this->prepareForWriting();
$this->timeout = $timeout;
$this->lastActivity = is_int($timeout) ? time() : null;
}
return $this->timeout;
}
/**
* Gets or sets the renewable flag
* Automatically renews the session if renewing gets enabled
*
* @param bool|null $renewable Optional new renewable flag to set
*/
public function renewable(bool|null $renewable = null): bool
{
if ($renewable !== null) {
$this->prepareForWriting();
$this->renewable = $renewable;
$this->autoRenew();
}
return $this->renewable;
}
/**
* Returns the session data object
*
* @return \Kirby\Session\SessionData
*/
public function data()
{
return $this->data;
}
/**
* Magic call method that proxies all calls to session data methods
*
* @param string $name Method name (one of set, increment, decrement, get, pull, remove, clear)
* @param array $arguments Method arguments
*/
public function __call(string $name, array $arguments): mixed
{
// validate that we can handle the called method
$methods = [
'clear',
'decrement',
'get',
'increment',
'pull',
'remove',
'set'
];
if (in_array($name, $methods) === false) {
throw new BadMethodCallException([
'data' => ['method' => 'Session::' . $name],
'translate' => false
]);
}
return $this->data()->$name(...$arguments);
}
/**
* Writes all changes to the session to the session store
*/
public function commit(): void
{
// nothing to do if nothing changed or the session has been just created or destroyed
/**
* @todo The $this->destroyed check gets flagged by Psalm for unknown reasons
* @psalm-suppress ParadoxicalCondition
*/
if (
$this->writeMode !== true ||
$this->tokenExpiry === null ||
$this->destroyed === true
) {
return;
}
// collect all data
if ($this->newSession !== null) {
// the token has changed
// we are writing to the old session: it only gets the reference to the new session
// and a shortened expiry time (30 second grace period)
$data = [
'startTime' => $this->startTime(),
'expiryTime' => time() + 30,
'newSession' => $this->newSession[0]
];
// include the token key for the new session if we
// have access to the PHP `sodium` extension;
// otherwise (if no encryption is possible), the token key
// is omitted, which makes the new session read-only
// when accessed through the old session
if ($crypto = $this->crypto()) {
// encrypt the new token key with the old token key
// so that attackers with read access to the session file
// (e.g. via directory traversal) cannot impersonate the new session
$data['newSessionKey'] = $crypto->encrypt($this->newSession[1]);
}
} else {
$data = [
'startTime' => $this->startTime(),
'expiryTime' => $this->expiryTime(),
'duration' => $this->duration(),
'timeout' => $this->timeout(),
'lastActivity' => $this->lastActivity,
'renewable' => $this->renewable(),
'data' => $this->data()->get()
];
}
// encode the data and attach an HMAC
$data = serialize($data);
$data = hash_hmac('sha256', $data, $this->tokenKey) . "\n" . $data;
// store the data
$this->sessions->store()->set($this->tokenExpiry, $this->tokenId, $data);
$this->sessions->store()->unlock($this->tokenExpiry, $this->tokenId);
$this->writeMode = false;
}
/**
* Entirely destroys the session
*/
public function destroy(): void
{
// no need to destroy new or destroyed sessions
if ($this->tokenExpiry === null || $this->destroyed === true) {
return;
}
// remove session file
$this->sessions->store()->destroy($this->tokenExpiry, $this->tokenId);
$this->destroyed = true;
$this->writeMode = false;
$this->needsRetransmission = false;
// remove cookie
if ($this->mode === 'cookie') {
Cookie::remove($this->sessions->cookieName());
}
}
/**
* Renews the session with the same session duration
* Renewing also regenerates the session token
*/
public function renew(): void
{
if ($this->renewable() !== true) {
throw new LogicException([
'key' => 'session.notRenewable',
'fallback' => 'Cannot renew a session that is not renewable, call $session->renewable(true) first',
'translate' => false,
]);
}
$this->prepareForWriting();
$this->expiryTime = time() + $this->duration();
$this->regenerateTokenIfNotNew();
}
/**
* Regenerates the session token
* The old token will keep its validity for a 30 second grace period
*/
public function regenerateToken(): void
{
// don't do anything for destroyed sessions
if ($this->destroyed === true) {
return;
}
$this->prepareForWriting();
// generate new token
$tokenExpiry = $this->expiryTime;
$tokenId = $this->sessions->store()->createId($tokenExpiry);
$tokenKey = bin2hex(random_bytes(32));
// mark the old session as moved if there is one
if ($this->tokenExpiry !== null) {
$this->newSession = [$tokenExpiry . '.' . $tokenId, $tokenKey];
$this->commit();
// we are now in the context of the new session
$this->newSession = null;
}
// set new data as instance vars
$this->tokenExpiry = $tokenExpiry;
$this->tokenId = $tokenId;
$this->tokenKey = $tokenKey;
// the new session needs to be written for the first time
$this->writeMode = true;
// (re)transmit session token
if ($this->mode === 'cookie') {
Cookie::set($this->sessions->cookieName(), $this->token(), [
'lifetime' => $this->tokenExpiry,
'path' => Url::index(['host' => null, 'trailingSlash' => true]),
'secure' => Url::scheme() === 'https',
'httpOnly' => true,
'sameSite' => 'Lax'
]);
} else {
$this->needsRetransmission = true;
}
// update cache of the Sessions instance with the new token
$this->sessions->updateCache($this);
}
/**
* Returns whether the session token needs to be retransmitted to the client
* Only relevant in header and manual modes
*/
public function needsRetransmission(): bool
{
return $this->needsRetransmission;
}
/**
* Ensures that all pending changes are written
* to disk before the object is destructed
*
* @return void
*/
public function __destruct()
{
$this->commit();
}
/**
* Initially generates the token for new sessions
* Used internally
*/
public function ensureToken(): void
{
if ($this->tokenExpiry === null) {
$this->regenerateToken();
}
}
/**
* Puts the session into write mode by acquiring a lock
* and reloading the data
* @internal
*/
public function prepareForWriting(): void
{
// verify that we need to get into write mode:
// - new sessions are only written to if the token has explicitly been ensured
// using $session->ensureToken() -> lazy session creation
// - destroyed sessions are never written to
// - no need to lock and re-init if we are already in write mode
/**
* @todo The $this->destroyed check gets flagged by Psalm for unknown reasons
* @psalm-suppress ParadoxicalCondition
*/
if (
$this->tokenExpiry === null ||
$this->destroyed === true ||
$this->writeMode === true
) {
return;
}
// don't allow writing for read-only sessions
// (only the case for moved sessions when the PHP `sodium` extension is not available)
/**
* @todo This check gets flagged by Psalm for unknown reasons
* @psalm-suppress ParadoxicalCondition
*/
if ($this->tokenKey === null) {
throw new LogicException([
'key' => 'session.readonly',
'data' => ['token' => $this->token()],
'fallback' => 'Session "' . $this->token() . '" is currently read-only because it was accessed via an old session token',
'translate' => false
]);
}
$this->sessions->store()->lock($this->tokenExpiry, $this->tokenId);
$this->init();
$this->writeMode = true;
}
/**
* Returns a symmetric crypto instance based on the
* token key of the session
*/
protected function crypto(): SymmetricCrypto|null
{
if (
$this->tokenKey === null ||
SymmetricCrypto::isAvailable() === false
) {
return null; // @codeCoverageIgnore
}
return new SymmetricCrypto(secretKey: hex2bin($this->tokenKey));
}
/**
* Parses a token string into its parts and sets them as instance vars
*
* @param string $token Session token
* @param bool $withoutKey If true, $token is passed without key
*/
protected function parseToken(string $token, bool $withoutKey = false): void
{
// split the token into its parts
$parts = explode('.', $token);
// only continue if the token has exactly the right amount of parts
$expectedParts = ($withoutKey === true) ? 2 : 3;
if (count($parts) !== $expectedParts) {
throw new InvalidArgumentException([
'data' => ['method' => 'Session::parseToken', 'argument' => '$token'],
'translate' => false
]);
}
$tokenExpiry = (int)$parts[0];
$tokenId = $parts[1];
$tokenKey = ($withoutKey === true) ? null : $parts[2];
// verify that all parts were parsed correctly using reassembly
$expectedToken = $tokenExpiry . '.' . $tokenId;
if ($withoutKey === false) {
$expectedToken .= '.' . $tokenKey;
}
if ($expectedToken !== $token) {
throw new InvalidArgumentException([
'data' => ['method' => 'Session::parseToken', 'argument' => '$token'],
'translate' => false
]);
}
$this->tokenExpiry = $tokenExpiry;
$this->tokenId = $tokenId;
$this->tokenKey = $tokenKey;
}
/**
* Makes sure that the given value is a valid timestamp
*
* @param string|int $time Timestamp or date string (must be supported by `strtotime()`)
* @param int|null $now Timestamp to use as a base for the calculation of relative dates
* @return int Timestamp value
*/
protected static function timeToTimestamp(
string|int $time,
int|null $now = null
): int {
// default to current time as $now
$now ??= time();
// convert date strings to a timestamp first
if (is_string($time) === true) {
$time = strtotime($time, $now);
}
return $time;
}
/**
* Loads the session data from the session store
*/
protected function init(): void
{
// sessions that are new, written to or that have been destroyed should never be initialized
if (
$this->tokenExpiry === null ||
$this->writeMode === true ||
$this->destroyed === true
) {
// unexpected error that shouldn't occur
throw new Exception(['translate' => false]); // @codeCoverageIgnore
}
// make sure that the session exists
if ($this->sessions->store()->exists($this->tokenExpiry, $this->tokenId) !== true) {
throw new NotFoundException([
'key' => 'session.notFound',
'data' => ['token' => $this->token()],
'fallback' => 'Session "' . $this->token() . '" does not exist',
'translate' => false,
'httpCode' => 404
]);
}
// get the session data from the store
$data = $this->sessions->store()->get(
$this->tokenExpiry,
$this->tokenId
);
// verify HMAC
// skip if we don't have the key (only the case for moved sessions)
$hmac = Str::before($data, "\n");
$data = trim(Str::after($data, "\n"));
if (
$this->tokenKey !== null &&
hash_equals(hash_hmac('sha256', $data, $this->tokenKey), $hmac) !== true
) {
throw new LogicException([
'key' => 'session.invalid',
'data' => ['token' => $this->token()],
'fallback' => 'Session "' . $this->token() . '" is invalid',
'translate' => false,
'httpCode' => 500
]);
}
// decode the serialized data
$data = @unserialize($data);
if ($data === false) {
throw new LogicException([
'key' => 'session.invalid',
'data' => ['token' => $this->token()],
'fallback' => 'Session "' . $this->token() . '" is invalid',
'translate' => false,
'httpCode' => 500
]);
}
// verify start and expiry time
if (
time() < $data['startTime'] ||
time() > $data['expiryTime']
) {
throw new LogicException([
'key' => 'session.invalid',
'data' => ['token' => $this->token()],
'fallback' => 'Session "' . $this->token() . '" is invalid',
'translate' => false,
'httpCode' => 500
]);
}
// follow to the new session if there is one
if (isset($data['newSession']) === true) {
// decrypt the token key if provided and we have access to
// the PHP `sodium` extension for decryption
if (
isset($data['newSessionKey']) === true &&
$crypto = $this->crypto()
) {
$tokenKey = $crypto->decrypt($data['newSessionKey']);
$this->parseToken($data['newSession'] . '.' . $tokenKey);
$this->init();
return;
}
// otherwise initialize without the token key (read-only mode)
$this->parseToken($data['newSession'], true);
$this->init();
return;
}
// verify timeout
if (is_int($data['timeout']) === true) {
if (time() - $data['lastActivity'] > $data['timeout']) {
throw new LogicException([
'key' => 'session.invalid',
'data' => ['token' => $this->token()],
'fallback' => 'Session "' . $this->token() . '" is invalid',
'translate' => false,
'httpCode' => 500
]);
}
// set a new activity timestamp, but only every few minutes for better performance
// don't do this if another call to init() is already doing it to prevent endless loops;
// also don't do this for read-only sessions
if (
$this->updatingLastActivity === false &&
$this->tokenKey !== null &&
time() - $data['lastActivity'] > $data['timeout'] / 15
) {
$this->updatingLastActivity = true;
$this->prepareForWriting();
// the remaining init steps have been done by prepareForWriting()
$this->lastActivity = time();
$this->updatingLastActivity = false;
return;
}
}
// (re)initialize all instance variables
$this->startTime = $data['startTime'];
$this->expiryTime = $data['expiryTime'];
$this->duration = $data['duration'];
$this->timeout = $data['timeout'];
$this->lastActivity = $data['lastActivity'];
$this->renewable = $data['renewable'];
// reload data into existing object to avoid breaking memory references
if (isset($this->data) === true) {
$this->data()->reload($data['data']);
} else {
$this->data = new SessionData($this, $data['data']);
}
}
/**
* Regenerate session token, but only if there is already one
*/
protected function regenerateTokenIfNotNew(): void
{
if ($this->tokenExpiry !== null) {
$this->regenerateToken();
}
}
/**
* Automatically renews the session if possible and necessary
*/
protected function autoRenew(): void
{
// check if the session needs renewal at all
if ($this->needsRenewal() !== true) {
return;
}
// re-load the session and check again to make sure that no other thread
// already renewed the session in the meantime
$this->prepareForWriting();
if ($this->needsRenewal() === true) {
$this->renew();
}
}
/**
* Checks if the session can be renewed and if the last renewal
* was more than half a session duration ago
*/
protected function needsRenewal(): bool
{
return
$this->renewable() === true &&
$this->expiryTime() - time() < $this->duration() / 2;
}
}