Merge pull request #135 from simonlnu/master

[friendica.git] / include / security.php

diff --git a/include/security.php b/include/security.php
index 6b8128bdd8516cf406c13492a711cedda999b505..6ea515bffe41ff907b5bffb7ee1d237b0bc397f5 100755 (executable)
--- a/include/security.php
+++ b/include/security.php
@@ -202,7 +202,7 @@ function permissions_sql($owner_id,$remote_verified = false,$groups = null) {
                                " AND ( allow_cid = '' OR allow_cid REGEXP '<%d>' ) 
                                  AND ( deny_cid  = '' OR  NOT deny_cid REGEXP '<%d>' ) 
                                  AND ( allow_gid = '' OR allow_gid REGEXP '%s' )
-                                 AND ( deny_gid  = '' OR NOT deny_gid REGEXP '%s') 
+                                 AND ( deny_gid  = '' OR NOT deny_gid REGEXP '%s')
                                ",
                                intval($remote_user),
                                intval($remote_user),
@@ -212,4 +212,125 @@ function permissions_sql($owner_id,$remote_verified = false,$groups = null) {
                }
        }
        return $sql;
-}
\ No newline at end of file
+}
+
+
+function item_permissions_sql($owner_id,$remote_verified = false,$groups = null) {
+
+       $local_user = local_user();
+       $remote_user = remote_user();
+
+       /**
+        * Construct permissions
+        *
+        * default permissions - anonymous user
+        */
+
+       $sql = " AND allow_cid = '' 
+                        AND allow_gid = '' 
+                        AND deny_cid  = '' 
+                        AND deny_gid  = '' 
+                        AND private = 0
+       ";
+
+       /**
+        * Profile owner - everything is visible
+        */
+
+       if(($local_user) && ($local_user == $owner_id)) {
+               $sql = ''; 
+       }
+
+       /**
+        * Authenticated visitor. Unless pre-verified, 
+        * check that the contact belongs to this $owner_id
+        * and load the groups the visitor belongs to.
+        * If pre-verified, the caller is expected to have already
+        * done this and passed the groups into this function.
+        */
+
+       elseif($remote_user) {
+
+               if(! $remote_verified) {
+                       $r = q("SELECT id FROM contact WHERE id = %d AND uid = %d AND blocked = 0 LIMIT 1",
+                               intval($remote_user),
+                               intval($owner_id)
+                       );
+                       if(count($r)) {
+                               $remote_verified = true;
+                               $groups = init_groups_visitor($remote_user);
+                       }
+               }
+               if($remote_verified) {
+               
+                       $gs = '<<>>'; // should be impossible to match
+
+                       if(is_array($groups) && count($groups)) {
+                               foreach($groups as $g)
+                                       $gs .= '|<' . intval($g) . '>';
+                       } 
+
+                       $sql = sprintf(
+                               " AND ( private = 0 OR ( private = 1 AND wall = 1 AND ( allow_cid = '' OR allow_cid REGEXP '<%d>' ) 
+                                 AND ( deny_cid  = '' OR  NOT deny_cid REGEXP '<%d>' ) 
+                                 AND ( allow_gid = '' OR allow_gid REGEXP '%s' )
+                                 AND ( deny_gid  = '' OR NOT deny_gid REGEXP '%s'))) 
+                               ",
+                               intval($remote_user),
+                               intval($remote_user),
+                               dbesc($gs),
+                               dbesc($gs)
+                       );
+               }
+       }
+
+       return $sql;
+}
+
+
+/*
+ * Functions used to protect against Cross-Site Request Forgery
+ * The security token has to base on at least one value that an attacker can't know - here it's the session ID and the private key.
+ * In this implementation, a security token is reusable (if the user submits a form, goes back and resubmits the form, maybe with small changes;
+ * or if the security token is used for ajax-calls that happen several times), but only valid for a certain amout of time (3hours).
+ * The "typename" seperates the security tokens of different types of forms. This could be relevant in the following case:
+ *    A security token is used to protekt a link from CSRF (e.g. the "delete this profile"-link).
+ *    If the new page contains by any chance external elements, then the used security token is exposed by the referrer.
+ *    Actually, important actions should not be triggered by Links / GET-Requests at all, but somethimes they still are,
+ *    so this mechanism brings in some damage control (the attacker would be able to forge a request to a form of this type, but not to forms of other types).
+ */ 
+function get_form_security_token($typename = "") {
+       $a = get_app();
+       
+       $timestamp = time();
+       $sec_hash = hash('whirlpool', $a->user["guid"] . $a->user["prvkey"] . session_id() . $timestamp . $typename);
+       
+       return $timestamp . "." . $sec_hash;
+}
+
+function check_form_security_token($typename = "", $formname = 'form_security_token') {
+       if (!x($_REQUEST, $formname)) return false;
+       $hash = $_REQUEST[$formname];
+       
+       $max_livetime = 10800; // 3 hours
+       
+       $a = get_app();
+       
+       $x = explode(".", $hash);
+       if (time() > (IntVal($x[0]) + $max_livetime)) return false;
+       
+       $sec_hash = hash('whirlpool', $a->user["guid"] . $a->user["prvkey"] . session_id() . $x[0] . $typename);
+       
+       return ($sec_hash == $x[1]);
+}
+
+function check_form_security_std_err_msg() {
+       return t('The form security token was not correct. This probably happened because the form has been opened for too long (>3 hours) before subitting it.') . EOL;
+}
+function check_form_security_token_redirectOnErr($err_redirect, $typename = "", $formname = 'form_security_token') {
+       if (!check_form_security_token($typename, $formname)) {
+               $a = get_app();
+               notice( check_form_security_std_err_msg() );
+               goaway($a->get_baseurl() . $err_redirect );
+       }
+}