82 lines
2.0 KiB
PHP
82 lines
2.0 KiB
PHP
<?php
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namespace App\LegacyEncrypter;
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use Illuminate\Contracts\Encryption\DecryptException;
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abstract class BaseEncrypter
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{
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/**
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* The encryption key.
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*
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* @var string
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*/
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protected $key;
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/**
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* Create a MAC for the given value.
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*
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* @param string $iv
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* @param string $value
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* @return string
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*/
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protected function hash($iv, $value)
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{
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return hash_hmac('sha256', $iv.$value, $this->key);
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}
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/**
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* Get the JSON array from the given payload.
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*
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* @param string $payload
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* @return array
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*
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* @throws \Illuminate\Contracts\Encryption\DecryptException
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*/
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protected function getJsonPayload($payload)
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{
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$payload = json_decode(base64_decode($payload), true);
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// If the payload is not valid JSON or does not have the proper keys set we will
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// assume it is invalid and bail out of the routine since we will not be able
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// to decrypt the given value. We'll also check the MAC for this encryption.
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if (! $payload || $this->invalidPayload($payload)) {
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throw new DecryptException('The payload is invalid.');
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}
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if (! $this->validMac($payload)) {
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throw new DecryptException('The MAC is invalid.');
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}
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return $payload;
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}
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/**
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* Verify that the encryption payload is valid.
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*
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* @param array|mixed $data
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* @return bool
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*/
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protected function invalidPayload($data)
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{
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return ! is_array($data) || ! isset($data['iv']) || ! isset($data['value']) || ! isset($data['mac']);
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}
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/**
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* Determine if the MAC for the given payload is valid.
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*
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* @param array $payload
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* @return bool
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*
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* @throws \RuntimeException
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*/
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protected function validMac(array $payload)
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{
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$bytes = random_bytes(16);
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$calcMac = hash_hmac('sha256', $this->hash($payload['iv'], $payload['value']), $bytes, true);
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return hash_equals(hash_hmac('sha256', $payload['mac'], $bytes, true), $calcMac);
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}
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}
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