71 lines
2.4 KiB
PHP
71 lines
2.4 KiB
PHP
<?php
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namespace Eher\OAuth\SignatureMethod;
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/**
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* The RSA-SHA1 signature method uses the RSASSA-PKCS1-v1_5 signature algorithm as defined in
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* [RFC3447] section 8.2 (more simply known as PKCS#1), using SHA-1 as the hash function for
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* EMSA-PKCS1-v1_5. It is assumed that the Consumer has provided its RSA public key in a
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* verified way to the Service Provider, in a manner which is beyond the scope of this
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* specification.
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* - Chapter 9.3 ("RSA-SHA1")
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*/
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abstract class RsaSha1 extends SignatureMethod {
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public function get_name() {
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return "RSA-SHA1";
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}
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// Up to the SP to implement this lookup of keys. Possible ideas are:
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// (1) do a lookup in a table of trusted certs keyed off of consumer
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// (2) fetch via http using a url provided by the requester
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// (3) some sort of specific discovery code based on request
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//
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// Either way should return a string representation of the certificate
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protected abstract function fetch_public_cert(&$request);
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// Up to the SP to implement this lookup of keys. Possible ideas are:
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// (1) do a lookup in a table of trusted certs keyed off of consumer
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//
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// Either way should return a string representation of the certificate
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protected abstract function fetch_private_cert(&$request);
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public function build_signature($request, $consumer, $token) {
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$base_string = $request->get_signature_base_string();
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$request->base_string = $base_string;
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// Fetch the private key cert based on the request
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$cert = $this->fetch_private_cert($request);
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// Pull the private key ID from the certificate
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$privatekeyid = openssl_get_privatekey($cert);
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// Sign using the key
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$ok = openssl_sign($base_string, $signature, $privatekeyid);
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// Release the key resource
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openssl_free_key($privatekeyid);
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return base64_encode($signature);
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}
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public function check_signature($request, $consumer, $token, $signature) {
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$decoded_sig = base64_decode($signature);
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$base_string = $request->get_signature_base_string();
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// Fetch the public key cert based on the request
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$cert = $this->fetch_public_cert($request);
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// Pull the public key ID from the certificate
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$publickeyid = openssl_get_publickey($cert);
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// Check the computed signature against the one passed in the query
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$ok = openssl_verify($base_string, $decoded_sig, $publickeyid);
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// Release the key resource
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openssl_free_key($publickeyid);
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return $ok == 1;
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}
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}
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