+
+
+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
+ */
+
+ $sql = " AND `item`.allow_cid = ''
+ AND `item`.allow_gid = ''
+ AND `item`.deny_cid = ''
+ AND `item`.deny_gid = ''
+ AND `item`.private = 0
+ ";
+
+ /**
+ * Profile owner - everything is visible
+ */
+
+ if($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) . '>';
+ }
+
+ $sql = sprintf(
+ /*" AND ( private = 0 OR ( private in (1,2) AND wall = 1 AND ( allow_cid = '' OR allow_cid REGEXP '<%d>' )
+ AND ( deny_cid = '' OR NOT deny_cid REGEXP '<%d>' )
+ AND ( allow_gid = '' OR allow_gid REGEXP '%s' )
+ AND ( deny_gid = '' OR NOT deny_gid REGEXP '%s')))
+ ",
+ intval($remote_user),
+ intval($remote_user),
+ dbesc($gs),
+ dbesc($gs)
+*/
+ " AND ( `item`.private = 0 OR ( `item`.private in (1,2) AND `item`.`wall` = 1
+ AND ( NOT (`item`.deny_cid REGEXP '<%d>' OR `item`.deny_gid REGEXP '%s')
+ AND ( `item`.allow_cid REGEXP '<%d>' OR `item`.allow_gid REGEXP '%s' OR ( `item`.allow_cid = '' AND `item`.allow_gid = '')))))
+ ",
+ intval($remote_user),
+ dbesc($gs),
+ intval($remote_user),
+ 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 == $x[1]);
+}
+
+function check_form_security_std_err_msg() {
+ return t('The form security token was not correct. This probably happened because the form has been opened for too long (>3 hours) before submitting it.') . EOL;
+}
+function check_form_security_token_redirectOnErr($err_redirect, $typename = '', $formname = 'form_security_token') {
+ if (!check_form_security_token($typename, $formname)) {
+ $a = get_app();
+ logger('check_form_security_token failed: user ' . $a->user['guid'] . ' - form element ' . $typename);
+ logger('check_form_security_token failed: _REQUEST data: ' . print_r($_REQUEST, true), LOGGER_DATA);
+ notice( check_form_security_std_err_msg() );
+ goaway($a->get_baseurl() . $err_redirect );
+ }
+}
+function check_form_security_token_ForbiddenOnErr($typename = '', $formname = 'form_security_token') {
+ if (!check_form_security_token($typename, $formname)) {
+ $a = get_app();
+ logger('check_form_security_token failed: user ' . $a->user['guid'] . ' - form element ' . $typename);
+ logger('check_form_security_token failed: _REQUEST data: ' . print_r($_REQUEST, true), LOGGER_DATA);
+ header('HTTP/1.1 403 Forbidden');
+ killme();
+ }
+}
+
+// Returns an array of group id's this contact is a member of.
+// This array will only contain group id's related to the uid of this
+// DFRN contact. They are *not* neccessarily unique across the entire site.
+
+
+if(! function_exists('init_groups_visitor')) {
+function init_groups_visitor($contact_id) {
+ $groups = array();
+ $r = q("SELECT `gid` FROM `group_member`
+ WHERE `contact-id` = %d ",
+ intval($contact_id)
+ );
+ if(count($r)) {
+ foreach($r as $rr)
+ $groups[] = $rr['gid'];
+ }
+ return $groups;
+}}
+