some heavy lifting porting the old salmon code

1 files changed, 201 insertions, 0 deletions

diff --git a/include/salmon.php b/include/salmon.php
new file mode 100644
index 000000000..e1895ab75
--- /dev/null
+++ b/include/salmon.php
@@ -0,0 +1,201 @@
+<?php
+
+require_once('include/crypto.php');
+
+function get_salmon_key($uri,$keyhash) {
+	$ret = array();
+
+	logger('Fetching salmon key for ' . $uri, LOGGER_DEBUG, LOG_INFO);
+
+	$x = webfinger_rfc7033($uri,true);
+
+	logger('webfinger returns: ' . print_r($x,true), LOGGER_DATA, LOG_DEBUG);
+
+	if($x && array_key_exists('links',$x) && $x['links']) {
+		foreach($x['links'] as $link) {
+			if(array_key_exists('rel',$link) && $link['rel'] === 'magic-public-key') {
+				$ret[] = $link['href'];
+			}
+		}
+	}
+
+	else {
+		$arr = old_webfinger($uri);
+
+		logger('old webfinger returns: ' . print_r($arr,true), LOGGER_DATA, LOG_DEBUG);
+
+		if(is_array($arr)) {
+			foreach($arr as $a) {
+				if($a['@attributes']['rel'] === 'magic-public-key') {
+					$ret[] = $a['@attributes']['href'];
+				}
+			}
+		}
+		else {
+			return '';
+		}
+	}
+
+	// We have found at least one key URL
+	// If it's inline, parse it - otherwise get the key
+
+	if(count($ret)) {
+		for($x = 0; $x < count($ret); $x ++) {
+			if(substr($ret[$x],0,5) === 'data:') {
+				if(strstr($ret[$x],','))
+					$ret[$x] = substr($ret[$x],strpos($ret[$x],',')+1);
+				else
+					$ret[$x] = substr($ret[$x],5);
+			}
+			else
+				$ret[$x] = fetch_url($ret[$x]);
+		}
+	}
+
+
+	logger('Key located: ' . print_r($ret,true), LOGGER_DEBUG, LOG_INFO);
+
+	if(count($ret) == 1) {
+
+		// We only found one one key so we don't care if the hash matches.
+		// If it's the wrong key we'll find out soon enough because
+		// message verification will fail. This also covers some older
+		// software which don't supply a keyhash. As long as they only
+		// have one key we'll be right.
+
+		return $ret[0];
+	}
+	else {
+		foreach($ret as $a) {
+			$hash = base64url_encode(hash('sha256',$a));
+			if($hash == $keyhash)
+				return $a;
+		}
+	}
+
+	return '';
+}
+
+
+
+function slapper($owner,$url,$slap) {
+
+	// does contact have a salmon endpoint?
+
+	if(! strlen($url))
+		return;
+
+
+	if(! $owner['channel_prvkey']) {
+		logger(sprintf("channel '%s' (%d) does not have a salmon private key. Send failed.",
+		$owner['channel_address'],$owner['channel_id']));
+		return;
+	}
+
+	logger('slapper called for ' .$url . '. Data: ' . $slap, LOGGER_DATA, LOG_DEBUG);
+
+	// create a magic envelope
+
+	$data      = base64url_encode($slap);
+	$data_type = 'application/atom+xml';
+	$encoding  = 'base64url';
+	$algorithm = 'RSA-SHA256';
+	$keyhash   = base64url_encode(hash('sha256',salmon_key($owner['channel_pubkey'])),true);
+
+	// precomputed base64url encoding of data_type, encoding, algorithm concatenated with periods
+
+	$precomputed = '.YXBwbGljYXRpb24vYXRvbSt4bWw=.YmFzZTY0dXJs.UlNBLVNIQTI1Ng==';
+
+	$signature   = base64url_encode(rsa_sign(str_replace('=','',$data . $precomputed),$owner['channel_prvkey']));
+
+	$signature2  = base64url_encode(rsa_sign($data . $precomputed,$owner['channel_prvkey']));
+
+	$signature3  = base64url_encode(rsa_sign($data,$owner['channel_prvkey']));
+
+	$salmon_tpl = get_markup_template('magicsig.tpl');
+
+	$salmon = replace_macros($salmon_tpl,array(
+		'$data'      => $data,
+		'$encoding'  => $encoding,
+		'$algorithm' => $algorithm,
+		'$keyhash'   => $keyhash,
+		'$signature' => $signature
+	));
+
+	// slap them
+
+	$redirects = 0;
+
+	$ret = z_post_url($url,$salmon, $redirects, array('headers' => array(
+		'Content-type: application/magic-envelope+xml',
+		'Content-length: ' . strlen($salmon))
+	));
+
+
+	$return_code = $ret['return_code'];
+
+	// check for success, e.g. 2xx
+
+	if($return_code > 299) {
+
+		logger('compliant salmon failed. Falling back to status.net hack2');
+
+		// Entirely likely that their salmon implementation is
+		// non-compliant. Let's try once more, this time only signing
+		// the data, without stripping '=' chars
+
+		$salmon = replace_macros($salmon_tpl,array(
+			'$data'      => $data,
+			'$encoding'  => $encoding,
+			'$algorithm' => $algorithm,
+			'$keyhash'   => $keyhash,
+			'$signature' => $signature2
+		));
+
+		$redirects = 0;
+
+		$ret = z_post_url($url,$salmon, $redirects, array('headers' => array(
+			'Content-type: application/magic-envelope+xml',
+			'Content-length: ' . strlen($salmon))
+		));
+
+
+		$return_code = $ret['return_code'];
+
+		if($return_code > 299) {
+
+			logger('compliant salmon failed. Falling back to status.net hack3');
+
+			// Entirely likely that their salmon implementation is
+			// non-compliant. Let's try once more, this time only signing
+			// the data, without the precomputed blob
+
+			$salmon = replace_macros($salmon_tpl,array(
+				'$data'      => $data,
+				'$encoding'  => $encoding,
+				'$algorithm' => $algorithm,
+				'$keyhash'   => $keyhash,
+				'$signature' => $signature3
+			));
+
+			$redirects = 0;
+	
+			$ret = z_post_url($url,$salmon, $redirects, array('headers' => array(
+				'Content-type: application/magic-envelope+xml',
+				'Content-length: ' . strlen($salmon))
+			));
+
+
+			$return_code = $ret['return_code'];
+		}
+	}
+	logger('slapper for ' . $url . ' returned ' . $return_code);
+
+	if(! $return_code)
+		return(-1);
+	if(($return_code == 503) && (stristr($ret['header'],'retry-after')))
+		return(-1);
+
+	return ((($return_code >= 200) && ($return_code < 300)) ? 0 : 1);
+}
+