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<?php
/*********************************************************************************
* SugarCRM Community Edition is a customer relationship management program developed by
* SugarCRM, Inc. Copyright (C) 2004-2013 SugarCRM Inc.
*
* This program is free software; you can redistribute it and/or modify it under
* the terms of the GNU Affero General Public License version 3 as published by the
* Free Software Foundation with the addition of the following permission added
* to Section 15 as permitted in Section 7(a): FOR ANY PART OF THE COVERED WORK
* IN WHICH THE COPYRIGHT IS OWNED BY SUGARCRM, SUGARCRM DISCLAIMS THE WARRANTY
* OF NON INFRINGEMENT OF THIRD PARTY RIGHTS.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
* details.
*
* You should have received a copy of the GNU Affero General Public License along with
* this program; if not, see http://www.gnu.org/licenses or write to the Free
* Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301 USA.
*
* You can contact SugarCRM, Inc. headquarters at 10050 North Wolfe Road,
* SW2-130, Cupertino, CA 95014, USA. or at email address contact@sugarcrm.com.
*
* The interactive user interfaces in modified source and object code versions
* of this program must display Appropriate Legal Notices, as required under
* Section 5 of the GNU Affero General Public License version 3.
*
* In accordance with Section 7(b) of the GNU Affero General Public License version 3,
* these Appropriate Legal Notices must retain the display of the "Powered by
* SugarCRM" logo. If the display of the logo is not reasonably feasible for
* technical reasons, the Appropriate Legal Notices must display the words
* "Powered by SugarCRM".
********************************************************************************/
require_once 'include/php-sql-parser.php';
/**
* SQL Validator class
* @api
*/
class SugarSQLValidate
{
/**
* Parse SQL query WHERE and ORDER BY clauses and validate that nothing bad is happening there
* @param string $where
* @param string $order_by
* @return bool
*/
public function validateQueryClauses($where, $order_by = '')
{
if(empty($where) && empty($order_by)) {
return true;
}
if(empty($where) && !empty($order_by)) {
$where = "deleted=0";
}
$parser = new PHPSQLParser();
$testquery = "SELECT dummy FROM dummytable WHERE $where";
$clauses = 3;
if(!empty($order_by)) {
$testquery .= " ORDER BY $order_by";
$clauses++;
}
$parsed = $parser->parse($testquery);
//$GLOBALS['log']->debug("PARSE: ".var_export($parsed, true));
if(count($parsed) != $clauses) {
// we assume: SELECT, FROM, WHERE, maybe ORDER
return false;
}
$parts = array_keys($parsed);
if($parts[0] != "SELECT" || $parts[1] != "FROM" || $parts[2] != "WHERE") {
// check the keys to be SELECT, FROM, WHERE
return false;
}
if(!empty($order_by) && $parts[3] != "ORDER") {
// extra key is ORDER
return false;
}
// verify SELECT didn't change
if(count($parsed["SELECT"]) != 1 || $parsed["SELECT"][0] !== array ('expr_type' => 'colref','alias' => '`dummy`', 'base_expr' => 'dummy', 'sub_tree' => false)) {
$GLOBALS['log']->debug("validation failed SELECT");
return false;
}
// verify FROM didn't change
if(count($parsed["FROM"]) != 1 || $parsed["FROM"][0] !== array ('table' => 'dummytable', 'alias' => 'dummytable', 'join_type' => 'JOIN', 'ref_type' => '', 'ref_clause' => '', 'base_expr' => false, 'sub_tree' => false)) {
$GLOBALS['log']->debug("validation failed FROM");
return false;
}
// check WHERE
if(!$this->validateExpression($parsed["WHERE"], true)) {
$GLOBALS['log']->debug("validation failed WHERE");
return false;
}
// check ORDER
if(!empty($order_by) && !$this->validateExpression($parsed["ORDER"])) {
$GLOBALS['log']->debug("validation failed ORDER");
return false;
}
return true;
}
/**
* Prohibited functions
* @var array
*/
protected $bad_functions = array("benchmark", "encode", "sleep",
"generate_series", "load_file", "sys_eval", "user_name",
"xp_cmdshell", "sys_exec", "sp_replwritetovarbin");
/**
* Validate parsed SQL expression
* @param array $expr Parsed expression
* @return bool
*/
protected function validateExpression($expr, $allow_some_subqueries = false)
{
foreach($expr as $term) {
if(!is_array($term)) continue;
// check subtrees
if(isset($term['expr_type']) && $term['expr_type'] == 'subquery') {
if(!$allow_some_subqueries || !$this->allowedSubquery($term)) {
// subqueries are verboten, except for some very special ones
$GLOBALS['log']->debug("validation failed subquery");
return false;
}
} else {
if(!empty($term['sub_tree']) && !$this->validateExpression($term['sub_tree'], $allow_some_subqueries)) {
return false;
}
}
if(isset($term['type']) && $term['type'] == 'expression') {
continue;
}
if($term['expr_type'] == 'const' || $term['expr_type'] == 'expression') {
// constants are OK, expressions checked above
continue;
}
if($term['expr_type'] == 'function') {
// prohibit some functions
if(in_array(strtolower($term['base_expr']), $this->bad_functions)) {
$GLOBALS['log']->debug("validation failed function");
return false;
}
}
if($term['expr_type'] == 'colref' && !$this->validateColumnName($term['base_expr'])) {
// check column names
$GLOBALS['log']->debug("validation failed column name");
return false;
}
if(!empty($term['alias']) && $term['alias'] != $term['base_expr'] && $term['alias'] != "`".$term['base_expr']."`") {
$GLOBALS['log']->debug("validation failed alias: ".var_export($term, true));
return false;
}
}
return true;
}
/**
* Tables allowed in subqueries
* @var array
*/
protected $subquery_allowed_tables = array(
'email_addr_bean_rel' => true,
'email_addresses' => true,
'emails' => true,
'emails_beans' => true,
'emails_text' => true,
'teams' => true,
'team_sets_teams' => true);
/**
* Allow some subqueries to pass
* Needed since OPI uses subqueries for email searches... sigh
* @param array $term term structure of the subquery
*/
protected function allowedSubquery($term)
{
// Must be SELECT ... FROM ... WHERE ...
if(empty($term['sub_tree']) || empty($term['sub_tree']['SELECT']) || empty($term['sub_tree']['FROM']) || empty($term['sub_tree']['WHERE'])) {
$GLOBALS['log']->debug("subquery validation failed: missing item");
return false;
}
foreach($term['sub_tree']['SELECT'] as $select) {
if($select['expr_type'] == 'operator' && $select['base_expr'] == '*') {
continue;
}
if($select['expr_type'] != 'colref') {
$GLOBALS['log']->debug("subquery validation failed: column: {$select['expr_type']}");
// allow only columns in select
return false;
}
}
foreach($term['sub_tree']['FROM'] as $from) {
if(empty($this->subquery_allowed_tables[$from['table']])) {
$GLOBALS['log']->debug("subquery validation failed: table: {$from['table']}");
// only specific tables are allowed
return false;
}
if(!empty($from['ref_clause']) && !$this->validateQueryClauses($from['ref_clause'])) {
// validate join condition, if bad, bail out
$GLOBALS['log']->debug("subquery validation failed: join: {$from['ref_clause']}");
return false;
}
}
if(!$this->validateExpression($term['sub_tree']['WHERE'])) {
// validate where clause, no sub-subqueries allowed here
$GLOBALS['log']->debug("subquery validation failed: where clause");
return false;
}
return true;
}
/**
* validateColumnName
* This method validates the column name portion of the SQL statement and returns true if it is deemed safe.
* We check against querying for the user_hash column.
*
* @param $name String portion of the column name from SQL
* @return boolean True if column name is deemed safe, false otherwise
*/
protected function validateColumnName($name)
{
if($name == ",") return true; // sometimes , gets as column name
$name = strtolower($name); // case does not matter
$parts = explode(".", $name);
if(count($parts) > 2) {
// too many dots
return false;
}
foreach($parts AS $part)
{
//the user_hash column is forbidden in passed in SQL
if($part == "user_hash")
{
return false;
}
//Remove leading and trailing ` characters for the part
if(preg_match('/^[\`](.+?)[\`]$/', $part, $matches))
{
$part = $matches[1];
}
//We added an exception for # symbol (see Bug 50324)
//This should be removed when Bug 50360 is resolved
if(preg_match('/[^a-z0-9._#]/', $part)) {
// bad chars in name
return false;
}
}
return true;
}
}