4 files changed, 47 insertions, 1 deletions
diff --git a/phpBB/includes/functions.php b/phpBB/includes/functions.php
index 8017c379f3..817111491f 100644
--- a/phpBB/includes/functions.php
+++ b/phpBB/includes/functions.php
@@ -3486,6 +3486,10 @@ function get_preg_expression($mode)
 			$inline = ($mode == 'relative_url') ? ')' : '';
 			return "(?:[a-z0-9\-._~!$&'($inline*+,;=:@|]+|%[\dA-F]{2})*(?:/(?:[a-z0-9\-._~!$&'($inline*+,;=:@|]+|%[\dA-F]{2})*)*(?:\?(?:[a-z0-9\-._~!$&'($inline*+,;=:@/?|]+|%[\dA-F]{2})*)?(?:\#(?:[a-z0-9\-._~!$&'($inline*+,;=:@/?|]+|%[\dA-F]{2})*)?";
 		break;
+
+		case 'table_prefix':
+			return '#^[a-zA-Z][a-zA-Z0-9_]*$#';
+		break;
 	}
 
 	return '';
diff --git a/phpBB/install/install_install.php b/phpBB/install/install_install.php
index 9fe0c8aed5..ccdcf211f1 100644
--- a/phpBB/install/install_install.php
+++ b/phpBB/install/install_install.php
@@ -546,6 +546,11 @@ class install_install extends module
 				$error[] = $lang['INST_ERR_NO_DB'];
 				$connect_test = false;
 			}
+			else if (!preg_match(get_preg_expression('table_prefix'), $data['table_prefix']))
+			{
+				$error[] = $lang['INST_ERR_DB_INVALID_PREFIX'];
+				$connect_test = false;
+			}
 			else
 			{
 				$connect_test = connect_check_db(true, $error, $available_dbms[$data['dbms']], $data['table_prefix'], $data['dbhost'], $data['dbuser'], htmlspecialchars_decode($data['dbpasswd']), $data['dbname'], $data['dbport']);
@@ -2032,7 +2037,7 @@ class install_install extends module
 		'dbname'				=> array('lang' => 'DB_NAME',		'type' => 'text:25:100', 'explain' => false),
 		'dbuser'				=> array('lang' => 'DB_USERNAME',	'type' => 'text:25:100', 'explain' => false),
 		'dbpasswd'				=> array('lang' => 'DB_PASSWORD',	'type' => 'password:25:100', 'explain' => false),
-		'table_prefix'			=> array('lang' => 'TABLE_PREFIX',	'type' => 'text:25:100', 'explain' => false),
+		'table_prefix'			=> array('lang' => 'TABLE_PREFIX',	'type' => 'text:25:100', 'explain' => true),
 	);
 	var $admin_config_options = array(
 		'legend1'				=> 'ADMIN_CONFIG',
diff --git a/phpBB/language/en/install.php b/phpBB/language/en/install.php
index befa7c6f40..f038177df4 100644
--- a/phpBB/language/en/install.php
+++ b/phpBB/language/en/install.php
@@ -232,6 +232,7 @@ $lang = array_merge($lang, array(
 	'INST_ERR'					=> 'Installation error',
 	'INST_ERR_DB_CONNECT'		=> 'Could not connect to the database, see error message below.',
 	'INST_ERR_DB_FORUM_PATH'	=> 'The database file specified is within your board directory tree. You should put this file in a non web-accessible location.',
+	'INST_ERR_DB_INVALID_PREFIX'=> 'The prefix you entered is invalid. It must start with an alphanumeric character and must only contain alphanumeric characters, numbers and underscores.',
 	'INST_ERR_DB_NO_ERROR'		=> 'No error message given.',
 	'INST_ERR_DB_NO_MYSQLI'		=> 'The version of MySQL installed on this machine is incompatible with the “MySQL with MySQLi Extension” option you have selected. Please try the “MySQL” option instead.',
 	'INST_ERR_DB_NO_SQLITE'		=> 'The version of the SQLite extension you have installed is too old, it must be upgraded to at least 2.8.2.',
@@ -352,6 +353,7 @@ $lang = array_merge($lang, array(
 
 	'TABLES_MISSING'			=> 'Could not find these tables<br />» <strong>%s</strong>.',
 	'TABLE_PREFIX'				=> 'Prefix for tables in database',
+	'TABLE_PREFIX_EXPLAIN'		=> 'The prefix must start with an alphanumeric character and must only contain alphanumeric characters, numbers and underscores.',
 	'TABLE_PREFIX_SAME'			=> 'The table prefix needs to be the one used by the software you are converting from.<br />» Specified table prefix was %s.',
 	'TESTS_PASSED'				=> 'Tests passed',
 	'TESTS_FAILED'				=> 'Tests failed',
diff --git a/tests/regex/table_prefix_test.php b/tests/regex/table_prefix_test.php
new file mode 100644
index 0000000000..67a18b4fbc
--- /dev/null
+++ b/tests/regex/table_prefix_test.php
@@ -0,0 +1,35 @@
+<?php
+/**
+*
+* @package testing
+* @copyright (c) 2011 phpBB Group
+* @license http://opensource.org/licenses/gpl-license.php GNU Public License
+*
+*/
+
+require_once dirname(__FILE__) . '/../../phpBB/includes/functions.php';
+
+class phpbb_regex_table_prefix_test extends phpbb_test_case
+{
+	public function table_prefix_test_data()
+	{
+		return array(
+			array('phpbb_', 1),
+			array('phpBB3', 1),
+			array('a', 1),
+
+			array('', 0),
+			array('_', 0),
+			array('a-', 0),
+			array("'", 0),
+		);
+	}
+
+	/**
+	* @dataProvider table_prefix_test_data
+	*/
+	public function test_table_prefix($prefix, $expected)
+	{
+		$this->assertEquals($expected, preg_match(get_preg_expression('table_prefix'), $prefix));
+	}
+}