friendica/mod/dfrn_confirm.php

<?php

// There are two possible entry points. 

function dfrn_confirm_post(&$a,$handsfree = null) {

	if(is_array($handsfree)) {

		// called directly from dfrn_request due to automatic friend acceptance
		// any $_POST parameters we may require are supplied in the $handsfree array

		$node = $handsfree['node'];
		$a->interactive = false; // notice() becomes a no-op since nobody is there to see it

	}
	else {
		if($a->argc > 1)
			$node = $a->argv[1];
	}

		// Main entry point. Our user received a friend request notification (perhaps 
		// from another site) and clicked 'Approve'. $POST['source_url'] is not set.
		// OR we have been called directly from dfrn_request ($handsfree != null) due to 
		// this being a page type which supports automatic friend acceptance.

	if(! x($_POST,'source_url')) {

		$uid = ((is_array($handsfree)) ? $handsfree['uid'] : local_user());

		if(! $uid) {
			notice( t('Permission denied.') . EOL );
			return;
		}	

		$user = q("SELECT * FROM `user` WHERE `uid` = %d LIMIT 1",
			intval($uid)
		);

		if(! $user) {
			notice( t('Profile not found.') . EOL );
			return;
		}	


		// These come from either the friend request notification form or $handsfree array.

		if(is_array($handsfree)) {
			$dfrn_id = $handsfree['dfrn_id'];
			$intro_id = $handsfree['intro_id'];
			$duplex = $handsfree['duplex'];
		}
		else {
			$dfrn_id  = ((x($_POST,'dfrn_id')) ? notags(trim($_POST['dfrn_id'])) : "");
			$intro_id = intval($_POST['intro_id']);
			$duplex   = intval($_POST['duplex']);
			$cid      = intval($_POST['contact_id']);
		}

		// The other person will have been issued an ID when they first requested friendship.
		// Locate their record. At this time, their record will have both pending and blocked set to 1. 
		// There won't be any dfrn_id if this is a network follower, so use the contact_id instead.

		$r = q("SELECT * FROM `contact` WHERE ( ( `issued-id` != '' AND `issued-id` = '%s' ) OR ( `id` = %d AND `id` != 0 ) ) AND `uid` = %d LIMIT 1",
				dbesc($dfrn_id),
				intval($cid),
				intval($uid)
		);

		if(! count($r)) {
			notice( t('Contact not found.') . EOL );
			return;
		}

		$contact = $r[0];

		$contact_id   = $contact['id'];
		$relation     = $contact['rel'];
		$site_pubkey  = $contact['site-pubkey'];
		$dfrn_confirm = $contact['confirm'];
		$aes_allow    = $contact['aes_allow'];


		if($contact['network'] === 'dfrn') {

			// Generate a key pair for all further communications with this person.
			// We have a keypair for every contact, and a site key for unknown people.
			// This provides a means to carry on relationships with other people if 
			// any single key is compromised. It is a robust key. We're much more 
			// worried about key leakage than anybody cracking it.  

			$res = openssl_pkey_new(array(
				'digest_alg' => 'whirlpool',
				'private_key_bits' => 4096,
				'encrypt_key' => false )
			);


			$private_key = '';

			openssl_pkey_export($res, $private_key);

			$pubkey = openssl_pkey_get_details($res);
			$public_key = $pubkey["key"];

			// Save the private key. Send them the public key.

			$r = q("UPDATE `contact` SET `prvkey` = '%s' WHERE `id` = %d AND `uid` = %d LIMIT 1",
				dbesc($private_key),
				intval($contact_id),
				intval($uid) 
			);

			$params = array();

			// Per the protocol document, we will verify both ends by encrypting the dfrn_id with our 
			// site private key (person on the other end can decrypt it with our site public key).
			// Then encrypt our profile URL with the other person's site public key. They can decrypt
			// it with their site private key. If the decryption on the other end fails for either
			// item, it indicates tampering or key failure on at least one site and we will not be 
			// able to provide a secure communication pathway.

			// If other site is willing to accept full encryption, (aes_allow is 1 AND we have php5.3 
			// or later) then we encrypt the personal public key we send them using AES-256-CBC and a 
			// random key which is encrypted with their site public key.  

			$src_aes_key = random_string();

			$result = '';
			openssl_private_encrypt($dfrn_id,$result,$user[0]['prvkey']);

			$params['dfrn_id'] = bin2hex($result);
			$params['public_key'] = $public_key;


			$my_url = $a->get_baseurl() . '/profile/' . $user[0]['nickname'];

			openssl_public_encrypt($my_url, $params['source_url'], $site_pubkey);
			$params['source_url'] = bin2hex($params['source_url']);

			if($aes_allow && function_exists('openssl_encrypt')) {
				openssl_public_encrypt($src_aes_key, $params['aes_key'], $site_pubkey);
				$params['aes_key'] = bin2hex($params['aes_key']);
				$params['public_key'] = bin2hex(openssl_encrypt($public_key,'AES-256-CBC',$src_aes_key));
			}

			$params['dfrn_version'] = DFRN_PROTOCOL_VERSION ;
			if($duplex == 1)
				$params['duplex'] = 1;

			// POST all this stuff to the other site.

			$res = post_url($dfrn_confirm,$params);

			// Now figure out what they responded. Try to be robust if the remote site is 
			// having difficulty and throwing up errors of some kind. 

			$leading_junk = substr($res,0,strpos($res,'<?xml'));

			$res = substr($res,strpos($res,'<?xml'));
			if(! strlen($res)) {

					// No XML at all, this exchange is messed up really bad.
					// We shouldn't proceed, because the xml parser might choke,
					// and $status is going to be zero, which indicates success.
					// We can hardly call this a success.  
	
				notice( t('Response from remote site was not understood.') . EOL);
				return;
			}

			if(strlen($leading_junk) && get_config('system','debugging')) {
	
					// This might be more common. Mixed error text and some XML.
					// If we're configured for debugging, show the text. Proceed in either case.

				notice( t('Unexpected response from remote site: ') . EOL . $leading_junk . EOL );
			}

			$xml = simplexml_load_string($res);
			$status = (int) $xml->status;
			$message = unxmlify($xml->message);   // human readable text of what may have gone wrong.
			switch($status) {
				case 0:
					notice( t("Confirmation completed successfully.") . EOL);
					if(strlen($message))
						notice( t('Remote site reported: ') . $message . EOL);
					break;
				case 1:
					// birthday paradox - generate new dfrn-id and fall through.
					$new_dfrn_id = random_string();
					$r = q("UPDATE contact SET `issued-id` = '%s' WHERE `id` = %d AND `uid` = %d LIMIT 1",
						dbesc($new_dfrn_id),
						intval($contact_id),
						intval($uid) 
					);

				case 2:
					notice( t("Temporary failure. Please wait and try again.") . EOL);
					if(strlen($message))
						notice( t('Remote site reported: ') . $message . EOL);
					break;


				case 3:
					notice( t("Introduction failed or was revoked.") . EOL);
					if(strlen($message))
						notice( t('Remote site reported: ') . $message . EOL);
					break;
				}

			if(($status == 0) && ($intro_id)) {
	
				// Success. Delete the notification.
	
				$r = q("DELETE FROM `intro` WHERE `id` = %d AND `uid` = %d LIMIT 1",
					intval($intro_id),
					intval($uid)
				);
				
			}

			if($status != 0) 
				return;
		}

		// We have now established a relationship with the other site.
		// Let's make our own personal copy of their profile photo so we don't have
		// to always load it from their site.

		require_once("Photo.php");

		$photos = import_profile_photo($contact['photo'],$uid,$contact_id);

		if($contact['network'] === 'dfrn') {

			$new_relation = REL_VIP;
			if(($relation == REL_FAN) || ($duplex))
				$new_relation = REL_BUD;

			$r = q("UPDATE `contact` SET `photo` = '%s', 
				`thumb` = '%s', 
				`rel` = %d, 
				`name-date` = '%s', 
				`uri-date` = '%s', 
				`avatar-date` = '%s', 
				`blocked` = 0, 
				`pending` = 0,
				`duplex` = %d,
				`network` = 'dfrn' WHERE `id` = %d LIMIT 1
			",
				dbesc($photos[0]),
				dbesc($photos[1]),
				intval($new_relation),
				dbesc(datetime_convert()),
				dbesc(datetime_convert()),
				dbesc(datetime_convert()),
				intval($duplex),
				intval($contact_id)
			);
		}
		else {  

			$notify = '';
			$poll   = '';

			// $contact['network'] !== 'dfrn'

			$arr = lrdd($contact['url']);
			if(count($arr)) {
				foreach($arr as $link) {
					if($link['@attributes']['rel'] === 'salmon')
						$notify = $link['@attributes']['href'];
					if($link['@attributes']['rel'] === NAMESPACE_FEED)
						$poll = $link['@attributes']['href'];
				}
			}

			$r = q("DELETE FROM `intro` WHERE `id` = %d AND `uid` = %d LIMIT 1",
				intval($intro_id),
				intval($uid)
			);

			$r = q("UPDATE `contact` SET `photo` = '%s', 
				`thumb` = '%s', 
				`name-date` = '%s', 
				`uri-date` = '%s', 
				`avatar-date` = '%s', 
				`notify` = '%s',
				`poll` = '%s',
				`blocked` = 0, 
				`pending` = 0
				WHERE `id` = %d LIMIT 1
			",
				dbesc($photos[0]),
				dbesc($photos[1]),
				dbesc(datetime_convert()),
				dbesc(datetime_convert()),
				dbesc(datetime_convert()),
				dbesc($notify),
				dbesc($poll),
				intval($contact_id)
			);			
		}

		if($r === false)
				notice( t('Unable to set contact photo.') . EOL);


		// Let's send our user to the contact editor in case they want to
		// do anything special with this new friend.

		if($handsfree === null)
			goaway($a->get_baseurl() . '/contacts/' . intval($contact_id));
		return;  //NOTREACHED

	}



	// End of first scenario. [Local confirmation of remote friend request].



	// Begin scenario two. This is the remote response to the above scenario.
	// This will take place on the site that originally initiated the friend request.
	// In the section above where the confirming party makes a POST and 
	// retrieves xml status information, they are communicating with the following code.

	if(x($_POST,'source_url')) {

		// We are processing an external confirmation to an introduction created by our user.

		$public_key = $_POST['public_key'];
		$dfrn_id    = hex2bin($_POST['dfrn_id']);
		$source_url = hex2bin($_POST['source_url']);
		$aes_key    = $_POST['aes_key'];
		$duplex     = $_POST['duplex'];
		$version_id = (float) $_POST['dfrn_version'];


		// If $aes_key is set, both of these items require unpacking from the hex transport encoding.

		if(x($aes_key)) {
			$aes_key = hex2bin($aes_key);
			$public_key = hex2bin($public_key);
		}

		// Find our user's account

		$r = q("SELECT * FROM `user` WHERE `nickname` = '%s' LIMIT 1",
			dbesc($node));

		if(! count($r)) {
			$message = t('No user record found for ') . '\'' . $node . '\'';
			xml_status(3,$message); // failure
			// NOTREACHED
		}

		$my_prvkey = $r[0]['prvkey'];
		$local_uid = $r[0]['uid'];


		if(! strstr($my_prvkey,'BEGIN RSA PRIVATE KEY')) {
			$message = t('Our site encryption key is apparently messed up.');
			xml_status(3,$message);
		}

		// verify everything

		$decrypted_source_url = "";
		openssl_private_decrypt($source_url,$decrypted_source_url,$my_prvkey);


		if(! strlen($decrypted_source_url)) {
			$message = t('Empty site URL was provided or URL could not be decrypted by us.');
			xml_status(3,$message);
			// NOTREACHED
		}

		$ret = q("SELECT * FROM `contact` WHERE `url` = '%s' AND `uid` = %d LIMIT 1",
			dbesc($decrypted_source_url),
			intval($local_uid)
		);

		if(! count($ret)) {
			// this is either a bogus confirmation (?) or we deleted the original introduction.
			$message = t('Contact record was not found for you on our site.');
			xml_status(3,$message);
			return; // NOTREACHED 
		}

		$relation = $ret[0]['rel'];

		// Decrypt all this stuff we just received

		$foreign_pubkey = $ret[0]['site-pubkey'];
		$dfrn_record    = $ret[0]['id'];

		$decrypted_dfrn_id = "";
		openssl_public_decrypt($dfrn_id,$decrypted_dfrn_id,$foreign_pubkey);

		if(strlen($aes_key)) {
			$decrypted_aes_key = "";
			openssl_private_decrypt($aes_key,$decrypted_aes_key,$my_prvkey);
			$dfrn_pubkey = openssl_decrypt($public_key,'AES-256-CBC',$decrypted_aes_key);
		}
		else {
			$dfrn_pubkey = $public_key;
		}

		$r = q("SELECT * FROM `contact` WHERE `dfrn-id` = '%s' LIMIT 1",
			dbesc($decrypted_dfrn_id),
			intval($local_uid)
		);
		if(count($r)) {
			$message = t('The ID provided by your system is a duplicate on our system. It should work if you try again.');
			xml_status(1,$message); // Birthday paradox - duplicate dfrn-id
			// NOTREACHED
		}

		$r = q("UPDATE `contact` SET `dfrn-id` = '%s', `pubkey` = '%s' WHERE `id` = %d LIMIT 1",
			dbesc($decrypted_dfrn_id),
			dbesc($dfrn_pubkey),
			intval($dfrn_record)
		);
		if(! count($r)) {
			$message = t('Unable to set your contact credentials on our system.');
			xml_status(3,$message);
		}

		// We're good but now we have to scrape the profile photo and send notifications.



		$r = q("SELECT `photo` FROM `contact` WHERE `id` = %d LIMIT 1",
			intval($dfrn_record));

		if(count($r))
			$photo = $r[0]['photo'];
		else
			$photo = $a->get_baseurl() . '/images/default-profile.jpg';
				
		require_once("Photo.php");

		$photos = import_profile_photo($photo,$local_uid,$dfrn_record);

		$new_relation = REL_FAN;
		if(($relation == REL_VIP) || ($duplex))
			$new_relation = REL_BUD;

		$r = q("UPDATE `contact` SET 
			`photo` = '%s', 
			`thumb` = '%s', 
			`rel` = %d, 
			`name-date` = '%s', 
			`uri-date` = '%s', 
			`avatar-date` = '%s', 
			`blocked` = 0, 
			`pending` = 0,
			`duplex` = %d, 
			`network` = 'dfrn' WHERE `id` = %d LIMIT 1
		",
			dbesc($photos[0]),
			dbesc($photos[1]),
			intval($new_relation),
			dbesc(datetime_convert()),
			dbesc(datetime_convert()),
			dbesc(datetime_convert()),
			intval($duplex),
			intval($dfrn_record)
		);
		if($r === false) {    // indicates schema is messed up or total db failure
			$message = t('Unable to update your contact profile details on our system');
			xml_status(3,$message);
		}

		// Otherwise everything seems to have worked and we are almost done. Yay!
		// Send an email notification

		$r = q("SELECT * FROM `contact` LEFT JOIN `user` ON `contact`.`uid` = `user`.`uid`
			WHERE `contact`.`id` = %d LIMIT 1",
			intval($dfrn_record)
		);
		if((count($r)) && ($r[0]['notify-flags'] & NOTIFY_CONFIRM)) {

			$tpl = (($new_relation == REL_BUD) 
				? load_view_file('view/friend_complete_eml.tpl')
				: load_view_file('view/intro_complete_eml.tpl'));
		
			$email_tpl = replace_macros($tpl, array(
				'$sitename' => $a->config['sitename'],
				'$siteurl' =>  $a->get_baseurl(),
				'$username' => $r[0]['username'],
				'$email' => $r[0]['email'],
				'$fn' => $r[0]['name'],
				'$dfrn_url' => $r[0]['url'],
				'$uid' => $newuid )
			);
	
			$res = mail($r[0]['email'], t("Connection accepted at ") . $a->config['sitename'],
				$email_tpl, 'From: ' . t('Administrator') . '@' . $_SERVER[SERVER_NAME] );
			if(!$res) {
				// pointless throwing an error here and confusing the person at the other end of the wire.
			}
		}
		xml_status(0); // Success
		return; // NOTREACHED

			////////////////////// End of this scenario ///////////////////////////////////////////////
	}

	// somebody arrived here by mistake or they are fishing. Send them to the homepage.

	goaway($a->get_baseurl());
	// NOTREACHED

}