185 lines
6.8 KiB
PHP
185 lines
6.8 KiB
PHP
<?php
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// +----------------------------------------------------------------------
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// | YwxApp [ WE CAN DO IT JUST THINK ]
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// +----------------------------------------------------------------------
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// | Copyright (c) 2026-2036 http://ywxapp.cn All rights reserved.
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// +----------------------------------------------------------------------
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// | Author: ywxapp<admin@ywxapp.cn>
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// +----------------------------------------------------------------------
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namespace ywxapp\utils;
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/**
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* 微信公众号消息加解密类 (JSON数组版) - 互通修复版
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* ✅ 严格PKCS#7填充验证 | ✅ 二进制安全随机数 | ✅ JSON字节一致性保障
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* 实测环境：PHP 7.4+ / Node.js 18+ / Chrome 115+
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*/
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class JsonCrypto
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{
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private $token;
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private $encodingAesKey;
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private $appId;
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const BLOCK_SIZE = 32;
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public function __construct($token, $encodingAesKey, $appId)
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{
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if (empty($token) || empty($appId) || strlen($encodingAesKey) !== 43) {
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throw new Exception("配置错误：Token/AppID不能为空，EncodingAESKey需为43位Base64字符串");
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}
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// 严格验证Base64字符集（防空格/换行等污染）
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if (!preg_match('/^[A-Za-z0-9+\/]{43}$/', $encodingAesKey)) {
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throw new Exception("EncodingAESKey包含非法字符（仅允许A-Z, a-z, 0-9, +, /）");
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}
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$this->token = $token;
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$this->encodingAesKey = base64_decode($encodingAesKey . '=', true);
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if ($this->encodingAesKey === false || strlen($this->encodingAesKey) !== 32) {
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throw new Exception("EncodingAESKey解码失败或长度错误（应为32字节）");
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}
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$this->appId = $appId;
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}
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/**
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* 加密消息 (数组 -> 标准JSON -> 拼接 -> PKCS#7 -> AES)
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* ✅ 与JS完全对齐：JSON无空格、无转义、严格UTF-8字节
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*/
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public function encrypt(array $data): string
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{
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// 核心修复1：强制生成与JS完全一致的JSON字节流
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$jsonPayload = json_encode($data, JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES);
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if ($jsonPayload === false) {
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throw new Exception("JSON编码失败: " . json_last_error_msg());
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}
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// 移除所有空格/换行（确保与JS的JSON.stringify(data, null, 0)字节一致）
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$jsonPayload = preg_replace('/\s+/', '', $jsonPayload);
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// 核心修复2：使用二进制安全随机数（与JS crypto.getRandomValues 对齐）
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$random = random_bytes(16); // PHP 7.0+ 原生支持
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// 拼接明文: random(16) + len(4, big-endian) + json + appId
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$msgLength = strlen($jsonPayload);
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$msgLengthBin = pack('N', $msgLength); // 大端序4字节
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$toBeEncrypted = $random . $msgLengthBin . $jsonPayload . $this->appId;
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// PKCS#7填充
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$paddedText = $this->pkcs7Pad($toBeEncrypted);
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// AES-256-CBC加密（IV=Key前16字节，无填充）
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$encrypted = openssl_encrypt(
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$paddedText,
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'AES-256-CBC',
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$this->encodingAesKey,
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OPENSSL_RAW_DATA | OPENSSL_ZERO_PADDING,
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substr($this->encodingAesKey, 0, 16)
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);
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if ($encrypted === false) {
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throw new Exception("AES加密失败: " . openssl_error_string());
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}
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return base64_encode($encrypted);
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}
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/**
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* 解密消息 (Base64 -> AES -> PKCS#7验证 -> 解析)
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* ✅ 严格填充验证 | ✅ 长度边界检查 | ✅ AppID原始字节比对
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*/
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public function decrypt(string $encryptedBase64): ?array
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{
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$ciphertext = base64_decode($encryptedBase64, true);
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if ($ciphertext === false || strlen($ciphertext) < 32) {
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return null;
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}
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$decrypted = openssl_decrypt(
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$ciphertext,
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'AES-256-CBC',
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$this->encodingAesKey,
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OPENSSL_RAW_DATA | OPENSSL_ZERO_PADDING,
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substr($this->encodingAesKey, 0, 16)
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);
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if ($decrypted === false) {
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return null;
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}
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// 核心修复3：严格PKCS#7填充验证（与JS逻辑完全一致）
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$unpadded = $this->pkcs7Unpad($decrypted);
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if ($unpadded === null || strlen($unpadded) < 20) {
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return null;
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}
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// 解析长度字段（大端序4字节）
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$msgLengthBin = substr($unpadded, 16, 4);
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if (strlen($msgLengthBin) !== 4) return null;
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$msgLength = unpack('N', $msgLengthBin)[1];
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// 严格边界检查（防越界）
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if ($msgLength <= 0 || (20 + $msgLength) > strlen($unpadded)) {
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return null;
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}
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// 提取JSON和AppID（原始字节比对，禁止trim/过滤）
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$jsonPayload = substr($unpadded, 20, $msgLength);
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$fromAppId = substr($unpadded, 20 + $msgLength);
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// 核心修复4：AppID原始字节比对（禁止字符过滤！）
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if ($fromAppId !== $this->appId) {
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// 调试用（生产环境建议移除）
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error_log("AppID mismatch! Expected: " . bin2hex($this->appId) . ", Got: " . bin2hex($fromAppId));
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return null;
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}
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$data = json_decode($jsonPayload, true, 512, JSON_THROW_ON_ERROR | JSON_UNESCAPED_UNICODE);
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return is_array($data) ? $data : null;
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}
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/**
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* 生成签名（与JS逻辑严格一致）
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*/
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public function generateSignature($timestamp, $nonce, $encryptMsg): string
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{
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$tmpArr = [$this->token, (string)$timestamp, (string)$nonce, (string)$encryptMsg];
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sort($tmpArr, SORT_STRING);
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return sha1(implode('', $tmpArr));
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}
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// =============== 私有辅助方法（关键修复区） ===============
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/**
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* PKCS#7填充（安全实现）
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*/
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private function pkcs7Pad(string $text): string
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{
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$padLen = self::BLOCK_SIZE - (strlen($text) % self::BLOCK_SIZE);
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return $text . str_repeat(chr($padLen), $padLen);
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}
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/**
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* PKCS#7严格验证与移除（核心修复！）
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* ✅ 验证填充长度范围
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* ✅ 验证所有填充字节值一致性
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* ✅ 验证填充长度不超过原文长度
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* ❌ 任何异常立即返回null（与JS行为一致）
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*/
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private function pkcs7Unpad(string $text): ?string
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{
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$textLen = strlen($text);
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if ($textLen === 0) return null;
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$pad = ord($text[$textLen - 1]);
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// 严格验证1：填充长度合法性
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if ($pad < 1 || $pad > self::BLOCK_SIZE || $pad > $textLen) {
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return null;
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}
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// 严格验证2：所有填充字节必须等于$pad值
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for ($i = $textLen - $pad; $i < $textLen; $i++) {
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if (ord($text[$i]) !== $pad) {
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return null;
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}
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}
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return substr($text, 0, -$pad);
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}
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} |