67 lines
1.7 KiB
PHP
67 lines
1.7 KiB
PHP
<?php
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/**
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* The MIT License
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* Copyright (c) 2007 Andy Smith
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*/
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namespace Abraham\TwitterOAuth;
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/**
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* A class for implementing a Signature Method
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* See section 9 ("Signing Requests") in the spec
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*/
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abstract class SignatureMethod
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{
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/**
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* Needs to return the name of the Signature Method (ie HMAC-SHA1)
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*
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* @return string
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*/
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abstract public function getName();
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/**
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* Build up the signature
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* NOTE: The output of this function MUST NOT be urlencoded.
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* the encoding is handled in OAuthRequest when the final
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* request is serialized
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*
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* @param Request $request
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* @param Consumer $consumer
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* @param Token $token
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*
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* @return string
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*/
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abstract public function buildSignature(Request $request, Consumer $consumer, Token $token = null);
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/**
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* Verifies that a given signature is correct
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*
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* @param Request $request
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* @param Consumer $consumer
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* @param Token $token
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* @param string $signature
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*
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* @return bool
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*/
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public function checkSignature(Request $request, Consumer $consumer, Token $token, $signature)
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{
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$built = $this->buildSignature($request, $consumer, $token);
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// Check for zero length, although unlikely here
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if (strlen($built) == 0 || strlen($signature) == 0) {
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return false;
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}
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if (strlen($built) != strlen($signature)) {
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return false;
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}
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// Avoid a timing leak with a (hopefully) time insensitive compare
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$result = 0;
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for ($i = 0; $i < strlen($signature); $i++) {
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$result |= ord($built{$i}) ^ ord($signature{$i});
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}
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return $result == 0;
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}
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}
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