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
|
<?php
require_once('library/asn1.php');
function salmon_key($pubkey) {
$lines = explode("\n",$pubkey);
unset($lines[0]);
unset($lines[count($lines)]);
$x = base64_decode(implode('',$lines));
$r = ASN_BASE::parseASNString($x);
$m = $r[0]->asnData[1]->asnData[0]->asnData[0]->asnData;
$e = $r[0]->asnData[1]->asnData[0]->asnData[1]->asnData;
return 'RSA' . '.' . $m . '.' . $e ;
}
function base64url_encode($s, $strip_padding = false) {
$s = strtr(base64_encode($s),'+/','-_');
if($strip_padding)
$s = str_replace('=','',$s);
return $s;
}
function base64url_decode($s) {
/*
* // Placeholder for new rev of salmon which strips base64 padding.
* // PHP base64_decode handles the un-padded input without requiring this step
* // Uncomment if you find you need it.
*
* $l = strlen($s);
* if(! strpos($s,'=')) {
* $m = $l % 4;
* if($m == 2)
* $s .= '==';
* if($m == 3)
* $s .= '=';
* }
*
*/
return base64_decode(strtr($s,'-_','+/'));
}
function get_salmon_key($uri,$keyhash) {
$ret = array();
logger('Fetching salmon key');
$arr = lrdd($uri);
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($ret,true));
if(count($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) {
logger('slapper called. Data: ' . $slap);
// does contact have a salmon endpoint?
if(! strlen($url))
return;
// add all namespaces to item
$namespaces = <<< EOT
<entry xmlns="http://www.w3.org/2005/Atom"
xmlns:thr="http://purl.org/syndication/thread/1.0"
xmlns:at="http://purl.org/atompub/tombstones/1.0"
xmlns:media="http://purl.org/syndication/atommedia"
xmlns:dfrn="http://purl.org/macgirvin/dfrn/1.0"
xmlns:as="http://activitystrea.ms/spec/1.0/"
xmlns:georss="http://www.georss.org/georss"
xmlns:poco="http://portablecontacts.net/spec/1.0" >
EOT;
$slap = str_replace('<entry>',$namespaces,$slap);
// 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['spubkey'])));
// Setup RSA stuff to PKCS#1 sign the data
set_include_path(get_include_path() . PATH_SEPARATOR . 'phpsec');
require_once('phpsec/Crypt/RSA.php');
$rsa = new CRYPT_RSA();
$rsa->signatureMode = CRYPT_RSA_SIGNATURE_PKCS1;
$rsa->setHash('sha256');
$rsa->loadKey($owner['sprvkey']);
// precomputed base64url encoding of data_type, encoding, algorithm concatenated with periods
$precomputed = '.YXBwbGljYXRpb24vYXRvbSt4bWw=.YmFzZTY0dXJs.UlNBLVNIQTI1Ng==';
$signature = base64url_encode($rsa->sign($data . $precomputed));
$signature2 = base64url_encode($rsa->sign($data));
$salmon_tpl = load_view_file('view/magicsig.tpl');
$salmon = replace_macros($salmon_tpl,array(
'$data' => $data,
'$encoding' => $encoding,
'$algorithm' => $algorithm,
'$keyhash' => $keyhash,
'$signature' => $signature
));
// slap them
post_url($url,$salmon, array(
'Content-type: application/magic-envelope+xml',
'Content-length: ' . strlen($salmon)
));
$a = get_app();
$return_code = $a->get_curl_code();
// check for success, e.g. 2xx
if($return_code > 299) {
logger('slapper: compliant salmon failed. Falling back to status.net hack');
// 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' => $signature2
));
// slap them
post_url($url,$salmon, array(
'Content-type: application/magic-envelope+xml',
'Content-length: ' . strlen($salmon)
));
$return_code = $a->get_curl_code();
}
logger('slapper returned ' . $return_code);
if(! $return_code)
return(-1);
return ((($return_code >= 200) && ($return_code < 300)) ? 0 : 1);
}
|
