The checks include making sure that the authentication cookie is set and pulling in the contents (if $cookie is not used).
Makes sure the cookie is not expired. Verifies the hash in cookie is what is should be and compares the two.
Pluggable function — this function can be replaced from a plugin. It means that this function is defined (works) only after all plugins are loaded (included), but before this moment this function has not defined. Therefore, you cannot call this and all functions depended on this function directly from a plugin code. They need to be called on plugins_loaded hook or later, for example on init hook.
Function replacement (override) — in must-use or regular plugin you can create a function with the same name, then it will replace this function.
function wp_validate_auth_cookie( $cookie = '', $scheme = '' ) {
$cookie_elements = wp_parse_auth_cookie( $cookie, $scheme );
if ( ! $cookie_elements ) {
/**
* Fires if an authentication cookie is malformed.
*
* @since 2.7.0
*
* @param string $cookie Malformed auth cookie.
* @param string $scheme Authentication scheme. Values include 'auth', 'secure_auth',
* or 'logged_in'.
*/
do_action( 'auth_cookie_malformed', $cookie, $scheme );
return false;
}
$scheme = $cookie_elements['scheme'];
$username = $cookie_elements['username'];
$hmac = $cookie_elements['hmac'];
$token = $cookie_elements['token'];
$expired = $cookie_elements['expiration'];
$expiration = $cookie_elements['expiration'];
// Allow a grace period for POST and Ajax requests.
if ( wp_doing_ajax() || 'POST' === $_SERVER['REQUEST_METHOD'] ) {
$expired += HOUR_IN_SECONDS;
}
// Quick check to see if an honest cookie has expired.
if ( $expired < time() ) {
/**
* Fires once an authentication cookie has expired.
*
* @since 2.7.0
*
* @param string[] $cookie_elements {
* Authentication cookie components. None of the components should be assumed
* to be valid as they come directly from a client-provided cookie value.
*
* @type string $username User's username.
* @type string $expiration The time the cookie expires as a UNIX timestamp.
* @type string $token User's session token used.
* @type string $hmac The security hash for the cookie.
* @type string $scheme The cookie scheme to use.
* }
*/
do_action( 'auth_cookie_expired', $cookie_elements );
return false;
}
$user = get_user_by( 'login', $username );
if ( ! $user ) {
/**
* Fires if a bad username is entered in the user authentication process.
*
* @since 2.7.0
*
* @param string[] $cookie_elements {
* Authentication cookie components. None of the components should be assumed
* to be valid as they come directly from a client-provided cookie value.
*
* @type string $username User's username.
* @type string $expiration The time the cookie expires as a UNIX timestamp.
* @type string $token User's session token used.
* @type string $hmac The security hash for the cookie.
* @type string $scheme The cookie scheme to use.
* }
*/
do_action( 'auth_cookie_bad_username', $cookie_elements );
return false;
}
$pass_frag = substr( $user->user_pass, 8, 4 );
$key = wp_hash( $username . '|' . $pass_frag . '|' . $expiration . '|' . $token, $scheme );
// If ext/hash is not present, compat.php's hash_hmac() does not support sha256.
$algo = function_exists( 'hash' ) ? 'sha256' : 'sha1';
$hash = hash_hmac( $algo, $username . '|' . $expiration . '|' . $token, $key );
if ( ! hash_equals( $hash, $hmac ) ) {
/**
* Fires if a bad authentication cookie hash is encountered.
*
* @since 2.7.0
*
* @param string[] $cookie_elements {
* Authentication cookie components. None of the components should be assumed
* to be valid as they come directly from a client-provided cookie value.
*
* @type string $username User's username.
* @type string $expiration The time the cookie expires as a UNIX timestamp.
* @type string $token User's session token used.
* @type string $hmac The security hash for the cookie.
* @type string $scheme The cookie scheme to use.
* }
*/
do_action( 'auth_cookie_bad_hash', $cookie_elements );
return false;
}
$manager = WP_Session_Tokens::get_instance( $user->ID );
if ( ! $manager->verify( $token ) ) {
/**
* Fires if a bad session token is encountered.
*
* @since 4.0.0
*
* @param string[] $cookie_elements {
* Authentication cookie components. None of the components should be assumed
* to be valid as they come directly from a client-provided cookie value.
*
* @type string $username User's username.
* @type string $expiration The time the cookie expires as a UNIX timestamp.
* @type string $token User's session token used.
* @type string $hmac The security hash for the cookie.
* @type string $scheme The cookie scheme to use.
* }
*/
do_action( 'auth_cookie_bad_session_token', $cookie_elements );
return false;
}
// Ajax/POST grace period set above.
if ( $expiration < time() ) {
$GLOBALS['login_grace_period'] = 1;
}
/**
* Fires once an authentication cookie has been validated.
*
* @since 2.7.0
*
* @param string[] $cookie_elements {
* Authentication cookie components.
*
* @type string $username User's username.
* @type string $expiration The time the cookie expires as a UNIX timestamp.
* @type string $token User's session token used.
* @type string $hmac The security hash for the cookie.
* @type string $scheme The cookie scheme to use.
* }
* @param WP_User $user User object.
*/
do_action( 'auth_cookie_valid', $cookie_elements, $user );
return $user->ID;
}