aboutsummaryrefslogtreecommitdiffstats
path: root/mod/receive.php
blob: f5a2eb7b6e62032a3ea591095fe58db8ed2cf794 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
<?php

/**
 * Diaspora endpoint
 */


require_once('include/salmon.php');
require_once('include/certfns.php');

function receive_return($val) {

	if($val >= 400)
		$err = 'Error';
	if($val >= 200 && $val < 300)
		$err = 'OK';

	logger('mod-diaspora returns ' . $val);	
	header($_SERVER["SERVER_PROTOCOL"] . ' ' . $val . ' ' . $err);
	killme();

}


function get_diaspora_key($uri) {
	$key = '';

	logger('Fetching diaspora key for: ' . $uri);

	$arr = lrdd($uri);

	if(is_array($arr)) {
		foreach($arr as $a) {
			if($a['@attributes']['rel'] === 'diaspora-public-key') {
				$key = base64_decode($a['@attributes']['href']);
			}
		}
	}
	else {
		return '';
	}

	if($key)
		return rsatopem($key);
	return '';
}
	
function receive_post(&$a) {

	if($a->argc != 3 || $a->argv[1] !== 'users')
		receive_return(500);

	$guid = $a->argv[2];

	$r = q("SELECT * FROM `user` WHERE `guid` = '%s' LIMIT 1",
		dbesc($guid)
	);
	if(! count($r))
		salmon_return(500);

	$importer = $r[0];

	$xml = $_POST['xml'];

	logger('mod-diaspora: new salmon ' . $xml, LOGGER_DATA);

	if(! $xml)
		receive_return(500);


	$basedom = parse_xml_string($xml);

	if($basedom)
		logger('parsed dom');

	$atom = $basedom->children(NAMESPACE_ATOM1);

	logger('atom: ' . count($atom));
	$encrypted_header = json_decode(base64_decode($atom->encrypted_header));

	print_r($encrypted_header);
	
	$encrypted_aes_key_bundle = base64_decode($encrypted_header->aes_key);
	$ciphertext = base64_decode($encrypted_header->ciphertext);

	logger('encrypted_aes: ' . print_r($encrypted_aes_key_bundle,true));
	logger('ciphertext: ' . print_r($ciphertext,true));

	$outer_key_bundle = '';
	openssl_private_decrypt($encrypted_aes_key_bundle,$outer_key_bundle,$localprvkey);

	logger('outer_bundle: ' . print_r($outer_key_bundle,true));

	$j_outer_key_bundle = json_decode($outer_key_bundle);

	$outer_iv = base64_decode($j_outer_key_bundle->iv);
	$outer_key = base64_decode($j_outer_key_bundle->key);

	$decrypted = mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $outer_key, $ciphertext, MCRYPT_MODE_CBC, $outer_iv);

	$decrypted = pkcs5_unpad($decrypted);

	logger('decrypted: ' . print_r($decrypted,true));

	/**
	 * $decrypted now contains something like
	 *
	 *  <decrypted_header>
	 *     <iv>8e+G2+ET8l5BPuW0sVTnQw==</iv>
	 *     <aes_key>UvSMb4puPeB14STkcDWq+4QE302Edu15oaprAQSkLKU=</aes_key>
	 *     <author>
	 *       <name>Ryan Hughes</name>
	 *       <uri>acct:galaxor@diaspora.pirateship.org</uri>
	 *     </author>
	 *  </decrypted_header>
	 */

	$idom = parse_xml_string($decrypted,false);

	$inner_iv = base64_decode($idom->iv);
	$inner_aes_key = base64_decode($idom->aes_key);

	logger('inner_iv: ' . $inner_iv);

	$dom = $basedom->children(NAMESPACE_SALMON_ME);

	if($dom)
		logger('have dom');

	logger('dom: ' . count($dom));
	// figure out where in the DOM tree our data is hiding

	if($dom->provenance->data)
		$base = $dom->provenance;
	elseif($dom->env->data)
		$base = $dom->env;
	elseif($dom->data)
		$base = $dom;
	
	if(! $base) {
		logger('mod-diaspora: unable to locate salmon data in xml ');
		dt_return(400);
	}


	// Stash the signature away for now. We have to find their key or it won't be good for anything.
	$signature = base64url_decode($base->sig);

	logger('signature: ' . bin2hex($signature));

	// unpack the  data

	// strip whitespace so our data element will return to one big base64 blob
	$data = str_replace(array(" ","\t","\r","\n"),array("","","",""),$base->data);
	// Add back the 60 char linefeeds
    $lines = str_split($data,60);
    $data = implode("\n",$lines);


	// stash away some other stuff for later

	$type = $base->data[0]->attributes()->type[0];
	$keyhash = $base->sig[0]->attributes()->keyhash[0];
	$encoding = $base->encoding;
	$alg = $base->alg;

	$signed_data = $data  . (($data[-1] != "\n") ? "\n" : '') . '.' . base64url_encode($type) . "\n" . '.' . base64url_encode($encoding) . "\n" . '.' . base64url_encode($alg) . "\n";

	logger('signed data: ' . $signed_data);

	// decode the data
	$data = base64url_decode($data);

	// Now pull out the inner encrypted blob

	$inner_encrypted = base64_decode($data);

	$inner_decrypted = 
	$inner_decrypted = mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $inner_aes_key, $inner_encrypted, MCRYPT_MODE_CBC, $inner_iv);

	$inner_decrypted = pkcs5_unpad($inner_decrypted);

	logger('inner_decrypted: ' . $inner_decrypted);



	if(! $author_link) {
		logger('mod-diaspora: Could not retrieve author URI.');
		receive_return(400);
	}

	// Once we have the author URI, go to the web and try to find their public key
	// *** or look it up locally ***

	logger('mod-diaspora: Fetching key for ' . $author_link );

	// Get diaspora public key (pkcs#1) and convert to pkcs#8
 	$key = get_diaspora_key($author_link);

	if(! $key) {
		logger('mod-salmon: Could not retrieve author key.');
		receive_return(400);
	}

	$verify = false;

	if (version_compare(PHP_VERSION, '5.3.0', '>=')) {
    	$verify = openssl_verify($signed_data,$signature,$key,'sha256');
	}
	else {
		// fallback sha256 verify for PHP < 5.3
		$rawsig = '';
		$hash = hash('sha256',$signed_data,true);
		openssl_public_decrypt($signature,$rawsig,$key);
		$verify = (($rawsig && substr($rawsig,-32) === $hash) ? true : false);
	}

	if(! $verify) {
		logger('mod-diaspora: Message did not verify. Discarding.');
		receive_return(400);
	}

	logger('mod-diaspora: Message verified.');

	// If we reached this point, the message is good. 
	// Now let's figure out if the author is allowed to send us stuff.

	$r = q("SELECT * FROM `contact` WHERE `network` = 'dspr' AND ( `url` = '%s' OR `alias` = '%s') 
		AND `uid` = %d LIMIT 1",
		dbesc($author_link),
		dbesc($author_link),
		intval($importer['uid'])
	);
	if(! count($r)) {
		logger('mod-diaspora: Author unknown to us.');
	}	

	// is this a follower? Or have we ignored the person?
	// If so we can not accept this post.

	if((count($r)) && (($r[0]['readonly']) || ($r[0]['rel'] == REL_VIP) || ($r[0]['blocked']))) {
		logger('mod-diaspora: Ignoring this author.');
		receive_return(202);
		// NOTREACHED
	}

	require_once('include/items.php');

	// Placeholder for hub discovery. We shouldn't find any hubs
	// since we supplied the fake feed header - and it doesn't have any.

	$hub = '';

	/**
	 *
	 * anti-spam measure: consume_feed will accept a follow activity from 
	 * this person (and nothing else) if there is no existing contact record.
	 *
	 */

	$contact_rec = ((count($r)) ? $r[0] : null);




// figure out what kind of diaspora message we have, and process accordingly.





	receive_return(200);
}