mirror of
https://github.com/pierre42100/comunic
synced 2024-09-29 03:22:49 +00:00
430 lines
17 KiB
PHP
Executable File
430 lines
17 KiB
PHP
Executable File
<?php
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/*
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ZeroBin - a zero-knowledge paste bin
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Please see project page: http://sebsauvage.net/wiki/doku.php?id=php:zerobin
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*/
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$VERSION='Alpha 0.19';
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if (version_compare(PHP_VERSION, '5.2.6') < 0) die('ZeroBin requiert php 5.2.6 ou une version supérieure pour fonctionner. Désolé.');
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require_once "lib/serversalt.php";
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require_once "lib/vizhash_gd_zero.php";
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// In case stupid admin has left magic_quotes enabled in php.ini:
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if (get_magic_quotes_gpc())
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{
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function stripslashes_deep($value) { $value = is_array($value) ? array_map('stripslashes_deep', $value) : stripslashes($value); return $value; }
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$_POST = array_map('stripslashes_deep', $_POST);
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$_GET = array_map('stripslashes_deep', $_GET);
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$_COOKIE = array_map('stripslashes_deep', $_COOKIE);
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}
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// trafic_limiter : Make sure the IP address makes at most 1 request every 10 seconds.
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// Will return false if IP address made a call less than 10 seconds ago.
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function trafic_limiter_canPass($ip)
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{
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$tfilename='./data/trafic_limiter.php';
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if (!is_file($tfilename))
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{
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file_put_contents($tfilename,"<?php\n\$GLOBALS['trafic_limiter']=array();\n?>", LOCK_EX);
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chmod($tfilename,0705);
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}
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require $tfilename;
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$tl=$GLOBALS['trafic_limiter'];
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if (!empty($tl[$ip]) && ($tl[$ip]+10>=time()))
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{
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return false;
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// FIXME: purge file of expired IPs to keep it small
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}
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$tl[$ip]=time();
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file_put_contents($tfilename, "<?php\n\$GLOBALS['trafic_limiter']=".var_export($tl,true).";\n?>", LOCK_EX);
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return true;
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}
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// Constant time string comparison.
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// (Used to deter time attacks on hmac checking. See section 2.7 of https://defuse.ca/audits/zerobin.htm)
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function slow_equals($a, $b)
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{
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$diff = strlen($a) ^ strlen($b);
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for($i = 0; $i < strlen($a) && $i < strlen($b); $i++)
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{
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$diff |= ord($a[$i]) ^ ord($b[$i]);
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}
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return $diff === 0;
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}
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/* Convert paste id to storage path.
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The idea is to creates subdirectories in order to limit the number of files per directory.
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(A high number of files in a single directory can slow things down.)
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eg. "f468483c313401e8" will be stored in "data/f4/68/f468483c313401e8"
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High-trafic websites may want to deepen the directory structure (like Squid does).
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eg. input 'e3570978f9e4aa90' --> output 'data/e3/57/'
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*/
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function dataid2path($dataid)
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{
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return 'data/'.substr($dataid,0,2).'/'.substr($dataid,2,2).'/';
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}
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/* Convert paste id to discussion storage path.
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eg. 'e3570978f9e4aa90' --> 'data/e3/57/e3570978f9e4aa90.discussion/'
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*/
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function dataid2discussionpath($dataid)
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{
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return dataid2path($dataid).$dataid.'.discussion/';
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}
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// Checks if a json string is a proper SJCL encrypted message.
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// False if format is incorrect.
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function validSJCL($jsonstring)
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{
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$accepted_keys=array('iv','v','iter','ks','ts','mode','adata','cipher','salt','ct');
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// Make sure content is valid json
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$decoded = json_decode($jsonstring);
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if ($decoded==null) return false;
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$decoded = (array)$decoded;
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// Make sure required fields are present
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foreach($accepted_keys as $k)
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{
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if (!array_key_exists($k,$decoded)) { return false; }
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}
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// Make sure some fields are base64 data
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if (base64_decode($decoded['iv'],$strict=true)==null) { return false; }
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if (base64_decode($decoded['salt'],$strict=true)==null) { return false; }
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if (base64_decode($decoded['cipher'],$strict=true)==null) { return false; }
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// Make sure no additionnal keys were added.
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if (count(array_intersect(array_keys($decoded),$accepted_keys))!=10) { return false; }
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// Reject data if entropy is too low
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$ct = base64_decode($decoded['ct'], $strict=true);
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if (strlen($ct) > strlen(gzdeflate($ct))) return false;
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// Make sure some fields have a reasonable size.
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if (strlen($decoded['iv'])>24) return false;
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if (strlen($decoded['salt'])>14) return false;
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return true;
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}
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// Delete a paste and its discussion.
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// Input: $pasteid : the paste identifier.
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function deletePaste($pasteid)
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{
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// Delete the paste itself
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unlink(dataid2path($pasteid).$pasteid);
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// Delete discussion if it exists.
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$discdir = dataid2discussionpath($pasteid);
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if (is_dir($discdir))
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{
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// Delete all files in discussion directory
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$dhandle = opendir($discdir);
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while (false !== ($filename = readdir($dhandle)))
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{
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if (is_file($discdir.$filename)) unlink($discdir.$filename);
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}
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closedir($dhandle);
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// Delete the discussion directory.
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rmdir($discdir);
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}
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}
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if (!empty($_POST['data'])) // Create new paste/comment
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{
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/* POST contains:
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data (mandatory) = json encoded SJCL encrypted text (containing keys: iv,salt,ct)
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All optional data will go to meta information:
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expire (optional) = expiration delay (never,5min,10min,1hour,1day,1week,1month,1year,burn) (default:never)
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opendiscusssion (optional) = is the discussion allowed on this paste ? (0/1) (default:0)
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syntaxcoloring (optional) = should this paste use syntax coloring when displaying.
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nickname (optional) = son encoded SJCL encrypted text nickname of author of comment (containing keys: iv,salt,ct)
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parentid (optional) = in discussion, which comment this comment replies to.
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pasteid (optional) = in discussion, which paste this comment belongs to.
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*/
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header('Content-type: application/json');
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$error = false;
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// Create storage directory if it does not exist.
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if (!is_dir('data'))
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{
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mkdir('data',0705);
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file_put_contents('data/.htaccess',"Allow from none\nDeny from all\n", LOCK_EX);
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}
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// Make sure last paste from the IP address was more than 10 seconds ago.
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if (!trafic_limiter_canPass($_SERVER['REMOTE_ADDR']))
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{ echo json_encode(array('status'=>1,'message'=>'Veuillez patienter 10 secondes entre chaque message s’il vous plaît.')); exit; }
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// Make sure content is not too big.
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$data = $_POST['data'];
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if (strlen($data)>2000000)
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{ echo json_encode(array('status'=>1,'message'=>'Le contenu est limité à 2 Mb de données chiffrées.')); exit; }
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// Make sure format is correct.
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if (!validSJCL($data))
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{ echo json_encode(array('status'=>1,'message'=>'Données incorrectes.')); exit; }
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// Read additional meta-information.
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$meta=array();
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// Read expiration date
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if (!empty($_POST['expire']))
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{
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$expire=$_POST['expire'];
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if ($expire=='5min') $meta['expire_date']=time()+5*60;
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elseif ($expire=='10min') $meta['expire_date']=time()+10*60;
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elseif ($expire=='1hour') $meta['expire_date']=time()+60*60;
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elseif ($expire=='1day') $meta['expire_date']=time()+24*60*60;
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elseif ($expire=='1week') $meta['expire_date']=time()+7*24*60*60;
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elseif ($expire=='1month') $meta['expire_date']=time()+30*24*60*60; // Well this is not *exactly* one month, it's 30 days.
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elseif ($expire=='1year') $meta['expire_date']=time()+365*24*60*60;
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}
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// Destroy the paste when it is read.
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if (!empty($_POST['burnafterreading']))
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{
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$burnafterreading = $_POST['burnafterreading'];
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if ($burnafterreading!='0' && $burnafterreading!='1') { $error=true; }
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if ($burnafterreading!='0') { $meta['burnafterreading']=true; }
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}
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// Read open discussion flag
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if (!empty($_POST['opendiscussion']))
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{
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$opendiscussion = $_POST['opendiscussion'];
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if ($opendiscussion!='0' && $opendiscussion!='1') { $error=true; }
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if ($opendiscussion!='0') { $meta['opendiscussion']=true; }
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}
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// Should we use syntax coloring when displaying ?
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if (!empty($_POST['syntaxcoloring']))
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{
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$syntaxcoloring = $_POST['syntaxcoloring'];
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if ($syntaxcoloring!='0' && $syntaxcoloring!='1') { $error=true; }
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if ($syntaxcoloring!='0') { $meta['syntaxcoloring']=true; }
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}
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// You can't have an open discussion on a "Burn after reading" paste:
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if (isset($meta['burnafterreading'])) unset($meta['opendiscussion']);
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// Optional nickname for comments
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if (!empty($_POST['nickname']))
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{
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$nick = $_POST['nickname'];
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if (!validSJCL($nick))
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{
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$error=true;
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}
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else
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{
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$meta['nickname']=$nick;
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// Generation of the anonymous avatar (Vizhash):
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// If a nickname is provided, we generate a Vizhash.
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// (We assume that if the user did not enter a nickname, he/she wants
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// to be anonymous and we will not generate the vizhash.)
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$vz = new vizhash16x16();
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$pngdata = $vz->generate($_SERVER['REMOTE_ADDR']);
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if ($pngdata!='') $meta['vizhash'] = 'data:image/png;base64,'.base64_encode($pngdata);
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// Once the avatar is generated, we do not keep the IP address, nor its hash.
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}
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}
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if ($error)
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{
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echo json_encode(array('status'=>1,'message'=>'Données incorrectes.'));
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exit;
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}
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// Add post date to meta.
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$meta['postdate']=time();
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// We just want a small hash to avoid collisions: Half-MD5 (64 bits) will do the trick.
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$dataid = substr(hash('md5',$data),0,16);
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$is_comment = (!empty($_POST['parentid']) && !empty($_POST['pasteid'])); // Is this post a comment ?
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$storage = array('data'=>$data);
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if (count($meta)>0) $storage['meta'] = $meta; // Add meta-information only if necessary.
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if ($is_comment) // The user posts a comment.
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{
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$pasteid = $_POST['pasteid'];
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$parentid = $_POST['parentid'];
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if (!preg_match('/\A[a-f\d]{16}\z/',$pasteid)) { echo json_encode(array('status'=>1,'message'=>'Données incorrectes.')); exit; }
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if (!preg_match('/\A[a-f\d]{16}\z/',$parentid)) { echo json_encode(array('status'=>1,'message'=>'Données incorrectes.')); exit; }
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unset($storage['expire_date']); // Comment do not expire (it's the paste that expires)
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unset($storage['opendiscussion']);
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unset($storage['syntaxcoloring']);
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// Make sure paste exists.
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$storagedir = dataid2path($pasteid);
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if (!is_file($storagedir.$pasteid)) { echo json_encode(array('status'=>1,'message'=>'Données incorrectes.')); exit; }
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// Make sure the discussion is opened in this paste.
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$paste=json_decode(file_get_contents($storagedir.$pasteid));
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if (!$paste->meta->opendiscussion) { echo json_encode(array('status'=>1,'message'=>'Données incorrectes.')); exit; }
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$discdir = dataid2discussionpath($pasteid);
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$filename = $pasteid.'.'.$dataid.'.'.$parentid;
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if (!is_dir($discdir)) mkdir($discdir,$mode=0705,$recursive=true);
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if (is_file($discdir.$filename)) // Oups... improbable collision.
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{
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echo json_encode(array('status'=>1,'message'=>'Vous n’avez pas de chance. Essayez à nouveau.'));
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exit;
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}
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file_put_contents($discdir.$filename,json_encode($storage), LOCK_EX);
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echo json_encode(array('status'=>0,'id'=>$dataid)); // 0 = no error
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exit;
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}
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else // a standard paste.
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{
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$storagedir = dataid2path($dataid);
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if (!is_dir($storagedir)) mkdir($storagedir,$mode=0705,$recursive=true);
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if (is_file($storagedir.$dataid)) // Oups... improbable collision.
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{
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echo json_encode(array('status'=>1,'message'=>'Vous n’avez pas de chance. Essayez à nouveau.'));
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exit;
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}
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// New paste
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file_put_contents($storagedir.$dataid,json_encode($storage), LOCK_EX);
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// Generate the "delete" token.
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// The token is the hmac of the pasteid signed with the server salt.
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// The paste can be delete by calling http://myserver.com/zerobin/?pasteid=<pasteid>&deletetoken=<deletetoken>
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$deletetoken = hash_hmac('sha1', $dataid , getServerSalt());
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echo json_encode(array('status'=>0,'id'=>$dataid,'deletetoken'=>$deletetoken)); // 0 = no error
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exit;
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}
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echo json_encode(array('status'=>1,'message'=>'Erreur du serveur.'));
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exit;
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}
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/* Process a paste deletion request.
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Returns an array ('',$ERRORMESSAGE,$STATUS)
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*/
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function processPasteDelete($pasteid,$deletetoken)
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{
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if (preg_match('/\A[a-f\d]{16}\z/',$pasteid)) // Is this a valid paste identifier ?
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{
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$filename = dataid2path($pasteid).$pasteid;
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if (!is_file($filename)) // Check that paste exists.
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{
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return array('','Ce texte n’existe pas, il a expiré ou a été supprimé.','');
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}
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}
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else
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{
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return array('','Données incorrectes.','');
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}
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if (!slow_equals($deletetoken, hash_hmac('sha1', $pasteid , getServerSalt()))) // Make sure token is valid.
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{
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return array('','Mauvais code de suppression. Le texte n’a pu être supprimé.','');
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}
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// Paste exists and deletion token is valid: Delete the paste.
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deletePaste($pasteid);
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return array('','','Texte a bien été supprimé.');
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}
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/* Process a paste fetch request.
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Returns an array ($CIPHERDATA,$ERRORMESSAGE,$STATUS)
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*/
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function processPasteFetch($pasteid)
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{
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if (preg_match('/\A[a-f\d]{16}\z/',$pasteid)) // Is this a valid paste identifier ?
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{
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$filename = dataid2path($pasteid).$pasteid;
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if (!is_file($filename)) // Check that paste exists.
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{
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return array('','Ce texte n’existe pas, il a expiré ou a été supprimé.','');
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}
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}
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else
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{
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return array('','Données incorrectes.','');
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}
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// Get the paste itself.
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$paste=json_decode(file_get_contents($filename));
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// See if paste has expired.
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if (isset($paste->meta->expire_date) && $paste->meta->expire_date<time())
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{
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deletePaste($pasteid); // Delete the paste
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return array('','Ce texte n’existe pas, il a expiré ou a été supprimé.','');
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}
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// We kindly provide the remaining time before expiration (in seconds)
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if (property_exists($paste->meta, 'expire_date')) $paste->meta->remaining_time = $paste->meta->expire_date - time();
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$messages = array($paste); // The paste itself is the first in the list of encrypted messages.
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// If it's a discussion, get all comments.
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if (property_exists($paste->meta, 'opendiscussion') && $paste->meta->opendiscussion)
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{
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$comments=array();
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$datadir = dataid2discussionpath($pasteid);
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if (!is_dir($datadir)) mkdir($datadir,$mode=0705,$recursive=true);
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$dhandle = opendir($datadir);
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while (false !== ($filename = readdir($dhandle)))
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{
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if (is_file($datadir.$filename))
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{
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$comment=json_decode(file_get_contents($datadir.$filename));
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// Filename is in the form pasteid.commentid.parentid:
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// - pasteid is the paste this reply belongs to.
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// - commentid is the comment identifier itself.
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// - parentid is the comment this comment replies to (It can be pasteid)
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$items=explode('.',$filename);
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$comment->meta->commentid=$items[1]; // Add some meta information not contained in file.
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$comment->meta->parentid=$items[2];
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$comments[$comment->meta->postdate]=$comment; // Store in table
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}
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}
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closedir($dhandle);
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ksort($comments); // Sort comments by date, oldest first.
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$messages = array_merge($messages, $comments);
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}
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$CIPHERDATA = json_encode($messages);
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// If the paste was meant to be read only once, delete it.
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if (property_exists($paste->meta, 'burnafterreading') && $paste->meta->burnafterreading) deletePaste($pasteid);
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return array($CIPHERDATA,'','');
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}
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$CIPHERDATA='';
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$ERRORMESSAGE='';
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$STATUS='';
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if (!empty($_GET['deletetoken']) && !empty($_GET['pasteid'])) // Delete an existing paste
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{
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list ($CIPHERDATA, $ERRORMESSAGE, $STATUS) = processPasteDelete($_GET['pasteid'],$_GET['deletetoken']);
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}
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else if (!empty($_SERVER['QUERY_STRING'])) // Return an existing paste.
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{
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list ($CIPHERDATA, $ERRORMESSAGE, $STATUS) = processPasteFetch($_SERVER['QUERY_STRING']);
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}
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require_once "lib/rain.tpl.class.php";
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header('Content-Type: text/html; charset=utf-8');
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$page = new RainTPL;
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$page->assign('CIPHERDATA',htmlspecialchars($CIPHERDATA,ENT_NOQUOTES)); // We escape it here because ENT_NOQUOTES can't be used in RainTPL templates.
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$page->assign('VERSION',$VERSION);
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$page->assign('ERRORMESSAGE',$ERRORMESSAGE);
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$page->assign('STATUS',$STATUS);
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$page->draw('page');
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?>
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