Automattic / jetpack

class.jetpack-data.php

<?php

use Automattic\Jetpack\Constants\Manager as Constants_Manager;

class Jetpack_Data {
	/*
	 * Used internally when we want to look for the Normal Blog Token
	 * without knowing its token key ahead of time.
	 */
	const MAGIC_NORMAL_TOKEN_KEY = ';normal;';

	/**
	 * Gets the requested token.
	 *
	 * Tokens are one of two types:
	 * 1. Blog Tokens: These are the "main" tokens. Each site typically has one Blog Token,
	 *    though some sites can have multiple "Special" Blog Tokens (see below). These tokens
	 *    are not associated with a user account. They represent the site's connection with
	 *    the Jetpack servers.
	 * 2. User Tokens: These are "sub-"tokens. Each connected user account has one User Token.
	 *
	 * All tokens look like "{$token_key}.{$private}". $token_key is a public ID for the
	 * token, and $private is a secret that should never be displayed anywhere or sent
	 * over the network; it's used only for signing things.
	 *
	 * Blog Tokens can be "Normal" or "Special".
	 * * Normal: The result of a normal connection flow. They look like
	 *   "{$random_string_1}.{$random_string_2}"
	 *   That is, $token_key and $private are both random strings.
	 *   Sites only have one Normal Blog Token. Normal Tokens are found in either
	 *   Jetpack_Options::get_option( 'blog_token' ) (usual) or the JETPACK_BLOG_TOKEN
	 *   constant (rare).
	 * * Special: A connection token for sites that have gone through an alternative
	 *   connection flow. They look like:
	 *   ";{$special_id}{$special_version};{$wpcom_blog_id};.{$random_string}"
	 *   That is, $private is a random string and $token_key has a special structure with
	 *   lots of semicolons.
	 *   Most sites have zero Special Blog Tokens. Special tokens are only found in the
	 *   JETPACK_BLOG_TOKEN constant.
	 *
	 * In particular, note that Normal Blog Tokens never start with ";" and that
	 * Special Blog Tokens always do.
	 *
	 * When searching for a matching Blog Tokens, Blog Tokens are examined in the following
	 * order:
	 * 1. Defined Special Blog Tokens (via the JETPACK_BLOG_TOKEN constant)
	 * 2. Stored Normal Tokens (via Jetpack_Options::get_option( 'blog_token' ))
	 * 3. Defined Normal Tokens (via the JETPACK_BLOG_TOKEN constant)
	 *
	 * @param int|false    $user_id   false: Return the Blog Token. int: Return that user's User Token.
	 * @param string|false $token_key If provided, check that the token matches the provided input.
	 *                                false                                : Use first token. Default.
	 *                                Jetpack_Data::MAGIC_NORMAL_TOKEN_KEY : Use first Normal Token.
	 *                                non-empty string                     : Use matching token
	 * @return object|false
	 */
	public static function get_access_token( $user_id = false, $token_key = false ) {
		$possible_special_tokens = array();
		$possible_normal_tokens  = array();

		if ( $user_id ) {

The expression $user_id of type false|integer is loosely compared to true; this is ambiguous if the integer can be zero. You might want to explicitly use !== null instead.

			if ( !$user_tokens = Jetpack_Options::get_option( 'user_tokens' ) ) {
				return false;
			}
			if ( $user_id === JETPACK_MASTER_USER ) {
				if ( !$user_id = Jetpack_Options::get_option( 'master_user' ) ) {
					return false;
				}
			}
			if ( !isset( $user_tokens[$user_id] ) || ! $user_tokens[$user_id] ) {
				return false;
			}
			$user_token_chunks = explode( '.', $user_tokens[$user_id] );
			if ( empty( $user_token_chunks[1] ) || empty( $user_token_chunks[2] ) ) {
				return false;
			}
			if ( $user_id != $user_token_chunks[2] ) {
				return false;
			}
			$possible_normal_tokens[] = "{$user_token_chunks[0]}.{$user_token_chunks[1]}";
		} else {
			$stored_blog_token = Jetpack_Options::get_option( 'blog_token' );
			if ( $stored_blog_token ) {
				$possible_normal_tokens[] = $stored_blog_token;
			}

			$defined_tokens = Constants_Manager::is_defined( 'JETPACK_BLOG_TOKEN' )
				? explode( ',', Constants_Manager::get_constant( 'JETPACK_BLOG_TOKEN' ) )
				: array();

			foreach ( $defined_tokens as $defined_token ) {
				if ( ';' === $defined_token[0] ) {
					$possible_special_tokens[] = $defined_token;
				} else {
					$possible_normal_tokens[] = $defined_token;
				}
			}
		}

		if ( self::MAGIC_NORMAL_TOKEN_KEY === $token_key ) {
			$possible_tokens = $possible_normal_tokens;
		} else {
			$possible_tokens = array_merge( $possible_special_tokens, $possible_normal_tokens );
		}

		if ( ! $possible_tokens ) {
			return false;
		}

		$valid_token = false;

		if ( false === $token_key ) {
			// Use first token.
			$valid_token = $possible_tokens[0];
		} elseif ( self::MAGIC_NORMAL_TOKEN_KEY === $token_key ) {
			// Use first normal token.
			$valid_token = $possible_tokens[0]; // $possible_tokens only contains normal tokens because of earlier check.
		} else {
			// Use the token matching $token_key or false if none.
			// Ensure we check the full key.
			$token_check = rtrim( $token_key, '.' ) . '.';

			foreach ( $possible_tokens as $possible_token ) {
				if ( hash_equals( substr( $possible_token, 0, strlen( $token_check ) ), $token_check ) ) {
					$valid_token = $possible_token;
					break;
				}
			}
		}

		if ( ! $valid_token ) {
			return false;
		}

		return (object) array(
			'secret' => $valid_token,
			'external_user_id' => (int) $user_id,
		);
	}
}