YOURLS/includes/functions-auth.php

748 lines
25 KiB
PHP

<?php
/**
* Function related to authentication functions and nonces
*/
/**
* Show login form if required
*
* @return void
*/
function yourls_maybe_require_auth() {
if( yourls_is_private() ) {
yourls_do_action( 'require_auth' );
require_once( YOURLS_INC.'/auth.php' );
} else {
yourls_do_action( 'require_no_auth' );
}
}
/**
* Check for valid user via login form or stored cookie. Returns true or an error message
*
* @return bool|string|mixed true if valid user, error message otherwise. Can also call yourls_die() or redirect to login page. Oh my.
*/
function yourls_is_valid_user() {
// Allow plugins to short-circuit the whole function
$pre = yourls_apply_filter( 'shunt_is_valid_user', null );
if ( null !== $pre ) {
return $pre;
}
// $unfiltered_valid : are credentials valid? Boolean value. It's "unfiltered" to allow plugins to eventually filter it.
$unfiltered_valid = false;
// Logout request
if( isset( $_GET['action'] ) && $_GET['action'] == 'logout' && isset( $_REQUEST['nonce'] ) ) {
// The logout nonce is associated to fake user 'logout' since at this point we don't know the real user
yourls_verify_nonce('admin_logout', $_REQUEST['nonce'], 'logout');
yourls_do_action( 'logout' );
yourls_store_cookie( '' );
return yourls__( 'Logged out successfully' );
}
// Check cookies or login request. Login form has precedence.
yourls_do_action( 'pre_login' );
// Determine auth method and check credentials
if
// API only: Secure (no login or pwd) and time limited token
// ?timestamp=12345678&signature=md5(totoblah12345678)
( yourls_is_API() &&
isset( $_REQUEST['timestamp'] ) && !empty($_REQUEST['timestamp'] ) &&
isset( $_REQUEST['signature'] ) && !empty($_REQUEST['signature'] )
)
{
yourls_do_action( 'pre_login_signature_timestamp' );
$unfiltered_valid = yourls_check_signature_timestamp();
}
elseif
// API only: Secure (no login or pwd)
// ?signature=md5(totoblah)
( yourls_is_API() &&
!isset( $_REQUEST['timestamp'] ) &&
isset( $_REQUEST['signature'] ) && !empty( $_REQUEST['signature'] )
)
{
yourls_do_action( 'pre_login_signature' );
$unfiltered_valid = yourls_check_signature();
}
elseif
// API or normal: login with username & pwd
( isset( $_REQUEST['username'] ) && isset( $_REQUEST['password'] )
&& !empty( $_REQUEST['username'] ) && !empty( $_REQUEST['password'] ) )
{
yourls_do_action( 'pre_login_username_password' );
$unfiltered_valid = yourls_check_username_password();
}
elseif
// Normal only: cookies
( !yourls_is_API() &&
isset( $_COOKIE[ yourls_cookie_name() ] ) )
{
yourls_do_action( 'pre_login_cookie' );
$unfiltered_valid = yourls_check_auth_cookie();
}
// Regardless of validity, allow plugins to filter the boolean and have final word
$valid = yourls_apply_filter( 'is_valid_user', $unfiltered_valid );
// Login for the win!
if ( $valid ) {
yourls_do_action( 'login' );
// (Re)store encrypted cookie if needed
if ( !yourls_is_API() ) {
yourls_store_cookie( YOURLS_USER );
// Login form : redirect to requested URL to avoid re-submitting the login form on page reload
if( isset( $_REQUEST['username'] ) && isset( $_REQUEST['password'] ) && isset( $_SERVER['REQUEST_URI'] ) ) {
// The return makes sure we exit this function before waiting for redirection.
// See #3189 and note in yourls_redirect()
return yourls_redirect( yourls_sanitize_url_safe($_SERVER['REQUEST_URI']) );
}
}
// Login successful
return true;
}
// Login failed
yourls_do_action( 'login_failed' );
if ( isset( $_REQUEST['username'] ) || isset( $_REQUEST['password'] ) ) {
return yourls__( 'Invalid username or password' );
} else {
return yourls__( 'Please log in' );
}
}
/**
* Check auth against list of login=>pwd. Sets user if applicable, returns bool
*
* @return bool true if login/pwd pair is valid (and sets user if applicable), false otherwise
*/
function yourls_check_username_password() {
global $yourls_user_passwords;
// If login form (not API), check for nonce
if(!yourls_is_API()) {
yourls_verify_nonce('admin_login');
}
if( isset( $yourls_user_passwords[ $_REQUEST['username'] ] ) && yourls_check_password_hash( $_REQUEST['username'], $_REQUEST['password'] ) ) {
yourls_set_user( $_REQUEST['username'] );
return true;
}
return false;
}
/**
* Check a submitted password sent in plain text against stored password which can be a salted hash
*
* @param string $user
* @param string $submitted_password
* @return bool
*/
function yourls_check_password_hash($user, $submitted_password ) {
global $yourls_user_passwords;
if( !isset( $yourls_user_passwords[ $user ] ) )
return false;
if ( yourls_has_phpass_password( $user ) ) {
// Stored password is hashed
list( , $hash ) = explode( ':', $yourls_user_passwords[ $user ] );
$hash = str_replace( '!', '$', $hash );
return ( yourls_phpass_check( $submitted_password, $hash ) );
} else if( yourls_has_md5_password( $user ) ) {
// Stored password is a salted md5 hash: "md5:<$r = rand(10000,99999)>:<md5($r.'thepassword')>"
list( , $salt, ) = explode( ':', $yourls_user_passwords[ $user ] );
return( $yourls_user_passwords[ $user ] == 'md5:'.$salt.':'.md5( $salt . $submitted_password ) );
} else {
// Password stored in clear text
return( $yourls_user_passwords[ $user ] === $submitted_password );
}
}
/**
* Overwrite plaintext passwords in config file with hashed versions.
*
* @since 1.7
* @param string $config_file Full path to file
* @return true|string if overwrite was successful, an error message otherwise
*/
function yourls_hash_passwords_now( $config_file ) {
if( !is_readable( $config_file ) ) {
yourls_debug_log( 'Cannot hash passwords: cannot read file ' . $config_file );
return 'cannot read file'; // not sure that can actually happen...
}
if( !is_writable( $config_file ) ) {
yourls_debug_log( 'Cannot hash passwords: cannot write file ' . $config_file );
return 'cannot write file';
}
$yourls_user_passwords = [];
// Include file to read value of $yourls_user_passwords
// Temporary suppress error reporting to avoid notices about redeclared constants
$errlevel = error_reporting();
error_reporting( 0 );
require $config_file;
error_reporting( $errlevel );
$configdata = file_get_contents( $config_file );
if( $configdata == false ) {
yourls_debug_log('Cannot hash passwords: file_get_contents() false with ' . $config_file);
return 'could not read file';
}
$to_hash = 0; // keep track of number of passwords that need hashing
foreach ( $yourls_user_passwords as $user => $password ) {
// avoid "deprecated" warning when password is null -- see test case in tests/data/auth/preg_replace_problem.php
$password ??= '';
if ( !yourls_has_phpass_password( $user ) && !yourls_has_md5_password( $user ) ) {
$to_hash++;
$hash = yourls_phpass_hash( $password );
// PHP would interpret $ as a variable, so replace it in storage.
$hash = str_replace( '$', '!', $hash );
$quotes = "'" . '"';
$pattern = "/[$quotes]" . preg_quote( $user, '/' ) . "[$quotes]\s*=>\s*[$quotes]" . preg_quote( $password, '/' ) . "[$quotes]/";
$replace = "'$user' => 'phpass:$hash' /* Password encrypted by YOURLS */ ";
$count = 0;
$configdata = preg_replace( $pattern, $replace, $configdata, -1, $count );
// There should be exactly one replacement. Otherwise, fast fail.
if ( $count != 1 ) {
yourls_debug_log( "Problem with preg_replace for password hash of user $user" );
return 'preg_replace problem';
}
}
}
if( $to_hash == 0 ) {
yourls_debug_log('Cannot hash passwords: no password found in ' . $config_file);
return 'no password found';
}
$success = file_put_contents( $config_file, $configdata );
if ( $success === FALSE ) {
yourls_debug_log( 'Failed writing to ' . $config_file );
return 'could not write file';
}
yourls_debug_log('Successfully encrypted passwords in ' . basename($config_file));
return true;
}
/**
* Create a password hash
*
* @since 1.7
* @param string $password password to hash
* @return string hashed password
*/
function yourls_phpass_hash( $password ) {
/**
* Filter for hashing algorithm. See https://www.php.net/manual/en/function.password-hash.php
* Hashing algos are available if PHP was compiled with it.
* PASSWORD_BCRYPT is always available.
*/
$algo = yourls_apply_filter('hash_algo', PASSWORD_BCRYPT);
/**
* Filter for hashing options. See https://www.php.net/manual/en/function.password-hash.php
* A typical option for PASSWORD_BCRYPT would be ['cost' => <int in range 4-31> ]
* We're leaving the options at default values, which means a cost of 10 for PASSWORD_BCRYPT.
*
* If willing to modify this, be warned about the computing time, as there is a 2^n factor.
* See https://gist.github.com/ozh/65a75392b7cb254131cc55afd28de99b for examples.
*/
$options = yourls_apply_filter('hash_options', [] );
return password_hash($password, $algo, $options);
}
/**
* Verify that a password matches a hash
*
* @since 1.7
* @param string $password clear (eg submitted in a form) password
* @param string $hash hash
* @return bool true if the hash matches the password, false otherwise
*/
function yourls_phpass_check( $password, $hash ) {
return password_verify($password, $hash);
}
/**
* Check to see if any passwords are stored as cleartext.
*
* @since 1.7
* @return bool true if any passwords are cleartext
*/
function yourls_has_cleartext_passwords() {
global $yourls_user_passwords;
foreach ( $yourls_user_passwords as $user => $pwdata ) {
if ( !yourls_has_md5_password( $user ) && !yourls_has_phpass_password( $user ) ) {
return true;
}
}
return false;
}
/**
* Check if a user has a md5 hashed password
*
* Check if a user password is 'md5:[38 chars]'.
* TODO: deprecate this when/if we have proper user management with password hashes stored in the DB
*
* @since 1.7
* @param string $user user login
* @return bool true if password hashed, false otherwise
*/
function yourls_has_md5_password( $user ) {
global $yourls_user_passwords;
return( isset( $yourls_user_passwords[ $user ] )
&& substr( $yourls_user_passwords[ $user ], 0, 4 ) == 'md5:'
&& strlen( $yourls_user_passwords[ $user ] ) == 42 // http://www.google.com/search?q=the+answer+to+life+the+universe+and+everything
);
}
/**
* Check if a user's password is hashed with password_hash
*
* Check if a user password is 'phpass:[lots of chars]'.
* (For historical reason we're using 'phpass' as an identifier.)
* TODO: deprecate this when/if we have proper user management with password hashes stored in the DB
*
* @since 1.7
* @param string $user user login
* @return bool true if password hashed with password_hash, otherwise false
*/
function yourls_has_phpass_password( $user ) {
global $yourls_user_passwords;
return( isset( $yourls_user_passwords[ $user ] )
&& substr( $yourls_user_passwords[ $user ], 0, 7 ) == 'phpass:'
);
}
/**
* Check auth against encrypted COOKIE data. Sets user if applicable, returns bool
*
* @return bool true if authenticated, false otherwise
*/
function yourls_check_auth_cookie() {
global $yourls_user_passwords;
foreach( $yourls_user_passwords as $valid_user => $valid_password ) {
if ( yourls_cookie_value( $valid_user ) === $_COOKIE[ yourls_cookie_name() ] ) {
yourls_set_user( $valid_user );
return true;
}
}
return false;
}
/**
* Check auth against signature and timestamp. Sets user if applicable, returns bool
*
* Original usage :
* http://sho.rt/yourls-api.php?timestamp=<timestamp>&signature=<md5 hash>&action=...
* Since 1.7.7 we allow a `hash` parameter and an arbitrary hashed signature, hashed
* with the `hash` function. Examples :
* http://sho.rt/yourls-api.php?timestamp=<timestamp>&signature=<sha512 hash>&hash=sha512&action=...
* http://sho.rt/yourls-api.php?timestamp=<timestamp>&signature=<crc32 hash>&hash=crc32&action=...
*
* @since 1.4.1
* @return bool False if signature or timestamp missing or invalid, true if valid
*/
function yourls_check_signature_timestamp() {
if( !isset( $_REQUEST['signature'] ) OR empty( $_REQUEST['signature'] )
OR !isset( $_REQUEST['timestamp'] ) OR empty( $_REQUEST['timestamp'] )
) {
return false;
}
// Exit if the timestamp argument is outdated or invalid
if( !yourls_check_timestamp( $_REQUEST['timestamp'] )) {
return false;
}
// if there is a hash argument, make sure it's part of the availables algos
$hash_function = isset($_REQUEST['hash']) ? (string)$_REQUEST['hash'] : 'md5';
if( !in_array($hash_function, hash_algos()) ) {
return false;
}
// Check signature & timestamp against all possible users
global $yourls_user_passwords;
foreach( $yourls_user_passwords as $valid_user => $valid_password ) {
if (
hash( $hash_function, $_REQUEST['timestamp'].yourls_auth_signature( $valid_user ) ) === $_REQUEST['signature']
or
hash( $hash_function, yourls_auth_signature( $valid_user ).$_REQUEST['timestamp'] ) === $_REQUEST['signature']
) {
yourls_set_user( $valid_user );
return true;
}
}
// Signature doesn't match known user
return false;
}
/**
* Check auth against signature. Sets user if applicable, returns bool
*
* @since 1.4.1
* @return bool False if signature missing or invalid, true if valid
*/
function yourls_check_signature() {
if( !isset( $_REQUEST['signature'] ) OR empty( $_REQUEST['signature'] ) )
return false;
// Check signature against all possible users
global $yourls_user_passwords;
foreach( $yourls_user_passwords as $valid_user => $valid_password ) {
if ( yourls_auth_signature( $valid_user ) === $_REQUEST['signature'] ) {
yourls_set_user( $valid_user );
return true;
}
}
// Signature doesn't match known user
return false;
}
/**
* Generate secret signature hash
*
* @param false|string $username Username to generate signature for, or false to use current user
* @return string Signature
*/
function yourls_auth_signature( $username = false ) {
if( !$username && defined('YOURLS_USER') ) {
$username = YOURLS_USER;
}
return ( $username ? substr( yourls_salt( $username ), 0, 10 ) : 'Cannot generate auth signature: no username' );
}
/**
* Check if timestamp is not too old
*
* @param int $time Timestamp to check
* @return bool True if timestamp is valid
*/
function yourls_check_timestamp( $time ) {
$now = time();
// Allow timestamp to be a little in the future or the past -- see Issue 766
return yourls_apply_filter( 'check_timestamp', abs( $now - (int)$time ) < yourls_get_nonce_life(), $time );
}
/**
* Store new cookie. No $user will delete the cookie.
*
* @param string $user User login, or empty string to delete cookie
* @return void
*/
function yourls_store_cookie( $user = '' ) {
// No user will delete the cookie with a cookie time from the past
if( !$user ) {
$time = time() - 3600;
} else {
$time = time() + yourls_get_cookie_life();
}
$path = yourls_apply_filter( 'setcookie_path', '/' );
$domain = yourls_apply_filter( 'setcookie_domain', parse_url( yourls_get_yourls_site(), PHP_URL_HOST ) );
$secure = yourls_apply_filter( 'setcookie_secure', yourls_is_ssl() );
$httponly = yourls_apply_filter( 'setcookie_httponly', true );
// Some browsers refuse to store localhost cookie
if ( $domain == 'localhost' )
$domain = '';
yourls_do_action( 'pre_setcookie', $user, $time, $path, $domain, $secure, $httponly );
if ( !headers_sent( $filename, $linenum ) ) {
yourls_setcookie( yourls_cookie_name(), yourls_cookie_value( $user ), $time, $path, $domain, $secure, $httponly );
} else {
// For some reason cookies were not stored: action to be able to debug that
yourls_do_action( 'setcookie_failed', $user );
yourls_debug_log( "Could not store cookie: headers already sent in $filename on line $linenum" );
}
}
/**
* Replacement for PHP's setcookie(), with support for SameSite cookie attribute
*
* @see https://github.com/GoogleChromeLabs/samesite-examples/blob/master/php.md
* @see https://stackoverflow.com/a/59654832/36850
* @see https://www.php.net/manual/en/function.setcookie.php
*
* @since 1.7.7
* @param string $name cookie name
* @param string $value cookie value
* @param int $expire time the cookie expires as a Unix timestamp (number of seconds since the epoch)
* @param string $path path on the server in which the cookie will be available on
* @param string $domain (sub)domain that the cookie is available to
* @param bool $secure if cookie should only be transmitted over a secure HTTPS connection
* @param bool $httponly if cookie will be made accessible only through the HTTP protocol
* @return bool setcookie() result : false if output sent before, true otherwise. This does not indicate whether the user accepted the cookie.
*/
function yourls_setcookie($name, $value, $expire, $path, $domain, $secure, $httponly) {
$samesite = yourls_apply_filter('setcookie_samesite', 'Lax' );
return(setcookie($name, $value, array(
'expires' => $expire,
'path' => $path,
'domain' => $domain,
'samesite' => $samesite,
'secure' => $secure,
'httponly' => $httponly,
)));
}
/**
* Set user name
*
* @param string $user Username
* @return void
*/
function yourls_set_user( $user ) {
if( !defined( 'YOURLS_USER' ) )
define( 'YOURLS_USER', $user );
}
/**
* Get YOURLS_COOKIE_LIFE value (ie the life span of an auth cookie in seconds)
*
* Use this function instead of directly using the constant. This way, its value can be modified by plugins
* on a per case basis
*
* @since 1.7.7
* @see includes/Config/Config.php
* @return integer cookie life span, in seconds
*/
function yourls_get_cookie_life() {
return yourls_apply_filter( 'get_cookie_life', YOURLS_COOKIE_LIFE );
}
/**
* Get YOURLS_NONCE_LIFE value (ie life span of a nonce in seconds)
*
* Use this function instead of directly using the constant. This way, its value can be modified by plugins
* on a per case basis
*
* @since 1.7.7
* @see includes/Config/Config.php
* @see https://en.wikipedia.org/wiki/Cryptographic_nonce
* @return integer nonce life span, in seconds
*/
function yourls_get_nonce_life() {
return yourls_apply_filter( 'get_nonce_life', YOURLS_NONCE_LIFE );
}
/**
* Get YOURLS cookie name
*
* The name is unique for each install, to prevent mismatch between sho.rt and very.sho.rt -- see #1673
*
* TODO: when multi user is implemented, the whole cookie stuff should be reworked to allow storing multiple users
*
* @since 1.7.1
* @return string unique cookie name for a given YOURLS site
*/
function yourls_cookie_name() {
return yourls_apply_filter( 'cookie_name', 'yourls_' . yourls_salt( yourls_get_yourls_site() ) );
}
/**
* Get auth cookie value
*
* @since 1.7.7
* @param string $user user name
* @return string cookie value
*/
function yourls_cookie_value( $user ) {
return yourls_apply_filter( 'set_cookie_value', yourls_salt( $user ?? '' ), $user );
}
/**
* Return a time-dependent string for nonce creation
*
* Actually, this returns a float: ceil rounds up a value but is of type float, see https://www.php.net/ceil
*
* @return float
*/
function yourls_tick() {
return ceil( time() / yourls_get_nonce_life() );
}
/**
* Return hashed string
*
* This function is badly named, it's not a salt or a salted string : it's a cryptographic hash.
*
* @since 1.4.1
* @param string $string string to salt
* @return string hashed string
*/
function yourls_salt( $string ) {
$salt = defined('YOURLS_COOKIEKEY') ? YOURLS_COOKIEKEY : md5(__FILE__) ;
return yourls_apply_filter( 'yourls_salt', hash_hmac( yourls_hmac_algo(), $string, $salt), $string );
}
/**
* Return an available hash_hmac() algorithm
*
* @since 1.8.3
* @return string hash_hmac() algorithm
*/
function yourls_hmac_algo() {
$algo = yourls_apply_filter( 'hmac_algo', 'sha256' );
if( !in_array( $algo, hash_hmac_algos() ) ) {
$algo = 'sha256';
}
return $algo;
}
/**
* Create a time limited, action limited and user limited token
*
* @param string $action Action to create nonce for
* @param false|string $user Optional user string, false for current user
* @return string Nonce token
*/
function yourls_create_nonce($action, $user = false ) {
if( false === $user ) {
$user = defined('YOURLS_USER') ? YOURLS_USER : '-1';
}
$tick = yourls_tick();
$nonce = substr( yourls_salt($tick . $action . $user), 0, 10 );
// Allow plugins to alter the nonce
return yourls_apply_filter( 'create_nonce', $nonce, $action, $user );
}
/**
* Echoes or returns a nonce field for inclusion into a form
*
* @param string $action Action to create nonce for
* @param string $name Optional name of nonce field -- defaults to 'nonce'
* @param false|string $user Optional user string, false if unspecified
* @param bool $echo True to echo, false to return nonce field
* @return string Nonce field
*/
function yourls_nonce_field($action, $name = 'nonce', $user = false, $echo = true ) {
$field = '<input type="hidden" id="'.$name.'" name="'.$name.'" value="'.yourls_create_nonce( $action, $user ).'" />';
if( $echo )
echo $field."\n";
return $field;
}
/**
* Add a nonce to a URL. If URL omitted, adds nonce to current URL
*
* @param string $action Action to create nonce for
* @param string $url Optional URL to add nonce to -- defaults to current URL
* @param string $name Optional name of nonce field -- defaults to 'nonce'
* @param false|string $user Optional user string, false if unspecified
* @return string URL with nonce added
*/
function yourls_nonce_url($action, $url = false, $name = 'nonce', $user = false ) {
$nonce = yourls_create_nonce( $action, $user );
return yourls_add_query_arg( $name, $nonce, $url );
}
/**
* Check validity of a nonce (ie time span, user and action match).
*
* Returns true if valid, dies otherwise (yourls_die() or die($return) if defined).
* If $nonce is false or unspecified, it will use $_REQUEST['nonce']
*
* @param string $action
* @param false|string $nonce Optional, string: nonce value, or false to use $_REQUEST['nonce']
* @param false|string $user Optional, string user, false for current user
* @param string $return Optional, string: message to die with if nonce is invalid
* @return bool|void True if valid, dies otherwise
*/
function yourls_verify_nonce($action, $nonce = false, $user = false, $return = '' ) {
// Get user
if( false === $user ) {
$user = defined('YOURLS_USER') ? YOURLS_USER : '-1';
}
// Get nonce value from $_REQUEST if not specified
if( false === $nonce && isset( $_REQUEST['nonce'] ) ) {
$nonce = $_REQUEST['nonce'];
}
// Allow plugins to short-circuit the rest of the function
if (yourls_apply_filter( 'verify_nonce', false, $action, $nonce, $user, $return ) === true) {
return true;
}
// What nonce should be
$valid = yourls_create_nonce( $action, $user );
if( $nonce === $valid ) {
return true;
} else {
if( $return )
die( $return );
yourls_die( yourls__( 'Unauthorized action or expired link' ), yourls__( 'Error' ), 403 );
}
}
/**
* Check if YOURLS_USER comes from environment variables
*
* @since 1.8.2
* @return bool true if YOURLS_USER and YOURLS_PASSWORD are defined as environment variables
*/
function yourls_is_user_from_env() {
return yourls_apply_filter('is_user_from_env', getenv('YOURLS_USER') && getenv('YOURLS_PASSWORD'));
}
/**
* Check if we should hash passwords in the config file
*
* By default, passwords are hashed. They are not if
* - there is no password in clear text in the config file (ie everything is already hashed)
* - the user defined constant YOURLS_NO_HASH_PASSWORD is true, see https://docs.yourls.org/guide/essentials/credentials.html#i-don-t-want-to-encrypt-my-password
* - YOURLS_USER and YOURLS_PASSWORD are provided by the environment, not the config file
*
* @since 1.8.2
* @return bool
*/
function yourls_maybe_hash_passwords() {
$hash = true;
if ( !yourls_has_cleartext_passwords()
OR (yourls_skip_password_hashing())
OR (yourls_is_user_from_env())
) {
$hash = false;
}
return yourls_apply_filter('maybe_hash_password', $hash );
}
/**
* Check if user setting for skipping password hashing is set
*
* @since 1.8.2
* @return bool
*/
function yourls_skip_password_hashing() {
return yourls_apply_filter('skip_password_hashing', defined('YOURLS_NO_HASH_PASSWORD') && YOURLS_NO_HASH_PASSWORD);
}