56 lines
1.4 KiB
PHP
56 lines
1.4 KiB
PHP
<?php
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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 OAuthSignatureMethod {
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/**
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* Needs to return the name of the Signature Method (ie HMAC-SHA1)
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* @return string
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*/
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abstract public function get_name();
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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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* @param OAuthRequest $request
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* @param OAuthConsumer $consumer
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* @param OAuthToken $token
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* @return string
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*/
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abstract public function build_signature($request, $consumer, $token);
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/**
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* Verifies that a given signature is correct
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* @param OAuthRequest $request
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* @param OAuthConsumer $consumer
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* @param OAuthToken $token
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* @param string $signature
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* @return bool
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*/
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public function check_signature($request, $consumer, $token, $signature) {
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$built = $this->build_signature($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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