Changelog

* fix(math): fix equation regexp

Fixes #702.

CHANGELOG.md

@@ -6,6 +6,32 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Security
+- Prevent PHP injection through malicious block name or include file name. This addresses CVE-2022-
+
+### Fixed
+- Math equation `max(x, y)` didn't work anymore [#721](https://github.com/smarty-php/smarty/issues/721)
+
+## [3.1.44] - 2022-01-18
+
+### Fixed
+- Fixed illegal characters bug in math function security check [#702](https://github.com/smarty-php/smarty/issues/702)
+
+## [3.1.43] - 2022-01-10
+
+### Security
+- Prevent evasion of the `static_classes` security policy. This addresses CVE-2021-21408
+
+## [3.1.42] - 2022-01-10
+
+### Security
+- Prevent arbitrary PHP code execution through maliciously crafted expression for the math function. This addresses CVE-2021-29454
+
+## [3.1.41] - 2022-01-09
+
+### Security
+- Rewrote the mailto function to not use `eval` when encoding with javascript
+
 ## [3.1.40] - 2021-10-13
 
 ### Changed

lexer/smarty_internal_templateparser.y

@@ -758,6 +758,9 @@ value(res)       ::= doublequoted_with_quotes(s). {
 
 
 value(res)    ::= varindexed(vi) DOUBLECOLON static_class_access(r). {
+    if ($this->security && $this->security->static_classes !== array()) {
+        $this->compiler->trigger_template_error('dynamic static class not allowed by security setting');
+    }
     $prefixVar = $this->compiler->getNewPrefixVariable();
     if (vi['var'] === '\'smarty\'') {
         $this->compiler->appendPrefixCode("<?php {$prefixVar} = ". $this->compiler->compileTag('private_special_variable',array(),vi['smarty_internal_index']).';?>');

libs/Smarty.class.php

@@ -111,7 +111,7 @@ class Smarty extends Smarty_Internal_TemplateBase
     /**
      * smarty version
      */
-    const SMARTY_VERSION = '3.1.40';
+    const SMARTY_VERSION = '3.1.44';
     /**
      * define variable scopes
      */

libs/plugins/function.mailto.php

@@ -94,22 +94,19 @@ function smarty_function_mailto($params)
         );
         return;
     }
-    // FIXME: (rodneyrehm) document.write() excues me what? 1998 has passed!
     if ($encode === 'javascript') {
-        $string = 'document.write(\'<a href="mailto:' . $address . '" ' . $extra . '>' . $text . '</a>\');';
+	    $string = '<a href="mailto:' . $address . '" ' . $extra . '>' . $text . '</a>';
         $js_encode = '';
         for ($x = 0, $_length = strlen($string); $x < $_length; $x++) {
             $js_encode .= '%' . bin2hex($string[ $x ]);
         }
-        return '<script type="text/javascript">eval(unescape(\'' . $js_encode . '\'))</script>';
+        return '<script type="text/javascript">document.write(unescape(\'' . $js_encode . '\'))</script>';
     } elseif ($encode === 'javascript_charcode') {
         $string = '<a href="mailto:' . $address . '" ' . $extra . '>' . $text . '</a>';
-        for ($x = 0, $y = strlen($string); $x < $y; $x++) {
+        for ($x = 0, $_length = strlen($string); $x < $_length; $x++) {
             $ord[] = ord($string[ $x ]);
         }
-        $_ret = "<script type=\"text/javascript\" language=\"javascript\">\n" . "{document.write(String.fromCharCode(" .
+	    return '<script type="text/javascript">document.write(String.fromCharCode(' . implode(',', $ord) . '))</script>';
-                implode(',', $ord) . "))" . "}\n" . "</script>\n";
-        return $_ret;
     } elseif ($encode === 'hex') {
         preg_match('!^(.*)(\?.*)$!', $address, $match);
         if (!empty($match[ 2 ])) {

libs/plugins/function.math.php

@@ -28,7 +28,12 @@ function smarty_function_math($params, $template)
             'int'   => true,
             'abs'   => true,
             'ceil'  => true,
+            'acos'   => true,
+            'acosh'   => true,
             'cos'   => true,
+            'cosh'   => true,
+            'deg2rad'   => true,
+            'rad2deg'   => true,
             'exp'   => true,
             'floor' => true,
             'log'   => true,
@@ -39,27 +44,51 @@ function smarty_function_math($params, $template)
             'pow'   => true,
             'rand'  => true,
             'round' => true,
+            'asin'   => true,
+            'asinh'   => true,
             'sin'   => true,
+            'sinh'   => true,
             'sqrt'  => true,
             'srand' => true,
-            'tan'   => true
+            'atan'   => true,
+            'atanh'   => true,
+            'tan'   => true,
+            'tanh'   => true
         );
+
     // be sure equation parameter is present
     if (empty($params[ 'equation' ])) {
         trigger_error("math: missing equation parameter", E_USER_WARNING);
         return;
     }
     $equation = $params[ 'equation' ];
+
+    // Remove whitespaces
+    $equation = preg_replace('/\s+/', '', $equation);
+
+    // Adapted from https://www.php.net/manual/en/function.eval.php#107377
+    $number = '(?:\d+(?:[,.]\d+)?|pi|π)'; // What is a number
+    $functionsOrVars = '((?:0x[a-fA-F0-9]+)|([a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*))';
+    $operators = '[,+\/*\^%-]'; // Allowed math operators
+    $regexp = '/^(('.$number.'|'.$functionsOrVars.'|('.$functionsOrVars.'\s*\((?1)+\)|\((?1)+\)))(?:'.$operators.'(?1))?)+$/';
+
+    if (!preg_match($regexp, $equation)) {
+        trigger_error("math: illegal characters", E_USER_WARNING);
+        return;
+    }
+
     // make sure parenthesis are balanced
     if (substr_count($equation, '(') !== substr_count($equation, ')')) {
         trigger_error("math: unbalanced parenthesis", E_USER_WARNING);
         return;
     }
+
     // disallow backticks
     if (strpos($equation, '`') !== false) {
         trigger_error("math: backtick character not allowed in equation", E_USER_WARNING);
         return;
     }
+
     // also disallow dollar signs
     if (strpos($equation, '$') !== false) {
         trigger_error("math: dollar signs not allowed in equation", E_USER_WARNING);
@@ -96,6 +125,7 @@ function smarty_function_math($params, $template)
     }
     $smarty_math_result = null;
     eval("\$smarty_math_result = " . $equation . ";");
+
     if (empty($params[ 'format' ])) {
         if (empty($params[ 'assign' ])) {
             return $smarty_math_result;

libs/sysplugins/smarty_internal_compile_block.php

@@ -125,7 +125,7 @@ class Smarty_Internal_Compile_Blockclose extends Smarty_Internal_Compile_Shared_
         // setup buffer for template function code
         $compiler->parser->current_buffer = new Smarty_Internal_ParseTree_Template();
         $output = "<?php\n";
-        $output .= "/* {block {$_name}} */\n";
+        $output .= $compiler->cStyleComment(" {block {$_name}} ") . "\n";
         $output .= "class {$_className} extends Smarty_Internal_Block\n";
         $output .= "{\n";
         foreach ($_block as $property => $value) {
@@ -155,7 +155,7 @@ class Smarty_Internal_Compile_Blockclose extends Smarty_Internal_Compile_Shared_
         }
         $output .= "}\n";
         $output .= "}\n";
-        $output .= "/* {/block {$_name}} */\n\n";
+        $output .= $compiler->cStyleComment(" {/block {$_name}} ") . "\n\n";
         $output .= "?>\n";
         $compiler->parser->current_buffer->append_subtree(
             $compiler->parser,

libs/sysplugins/smarty_internal_compile_function.php

@@ -134,7 +134,7 @@ class Smarty_Internal_Compile_Functionclose extends Smarty_Internal_CompileBase
         if ($compiler->template->compiled->has_nocache_code) {
             $compiler->parent_compiler->tpl_function[ $_name ][ 'call_name_caching' ] = $_funcNameCaching;
             $output = "<?php\n";
-            $output .= "/* {$_funcNameCaching} */\n";
+            $output .= $compiler->cStyleComment(" {$_funcNameCaching} ") . "\n";
             $output .= "if (!function_exists('{$_funcNameCaching}')) {\n";
             $output .= "function {$_funcNameCaching} (Smarty_Internal_Template \$_smarty_tpl,\$params) {\n";
             $output .= "ob_start();\n";
@@ -159,7 +159,7 @@ class Smarty_Internal_Compile_Functionclose extends Smarty_Internal_CompileBase
             $output .= "/*/%%SmartyNocache:{$compiler->template->compiled->nocache_hash}%%*/\";\n?>";
             $output .= "<?php echo str_replace('{$compiler->template->compiled->nocache_hash}', \$_smarty_tpl->compiled->nocache_hash, ob_get_clean());\n";
             $output .= "}\n}\n";
-            $output .= "/*/ {$_funcName}_nocache */\n\n";
+            $output .= $compiler->cStyleComment("/ {$_funcName}_nocache ") . "\n\n";
             $output .= "?>\n";
             $compiler->parser->current_buffer->append_subtree(
                 $compiler->parser,
@@ -179,7 +179,7 @@ class Smarty_Internal_Compile_Functionclose extends Smarty_Internal_CompileBase
         }
         $compiler->parent_compiler->tpl_function[ $_name ][ 'call_name' ] = $_funcName;
         $output = "<?php\n";
-        $output .= "/* {$_funcName} */\n";
+        $output .= $compiler->cStyleComment(" {$_funcName} ") . "\n";
         $output .= "if (!function_exists('{$_funcName}')) {\n";
         $output .= "function {$_funcName}(Smarty_Internal_Template \$_smarty_tpl,\$params) {\n";
         $output .= $_paramsCode;
@@ -196,7 +196,7 @@ class Smarty_Internal_Compile_Functionclose extends Smarty_Internal_CompileBase
         );
         $compiler->parser->current_buffer->append_subtree($compiler->parser, $_functionCode);
         $output = "<?php\n}}\n";
-        $output .= "/*/ {$_funcName} */\n\n";
+        $output .= $compiler->cStyleComment("/ {$_funcName} ") . "\n\n";
         $output .= "?>\n";
         $compiler->parser->current_buffer->append_subtree(
             $compiler->parser,

libs/sysplugins/smarty_internal_compile_include.php

@@ -318,14 +318,14 @@ class Smarty_Internal_Compile_Include extends Smarty_Internal_CompileBase
             }
             // get compiled code
             $compiled_code = "<?php\n\n";
-            $compiled_code .= "/* Start inline template \"{$sourceInfo}\" =============================*/\n";
+            $compiled_code .= $compiler->cStyleComment(" Start inline template \"{$sourceInfo}\" =============================") . "\n";
             $compiled_code .= "function {$tpl->compiled->unifunc} (Smarty_Internal_Template \$_smarty_tpl) {\n";
             $compiled_code .= "?>\n" . $tpl->compiler->compileTemplateSource($tpl, null, $compiler->parent_compiler);
             $compiled_code .= "<?php\n";
             $compiled_code .= "}\n?>\n";
             $compiled_code .= $tpl->compiler->postFilter($tpl->compiler->blockOrFunctionCode);
             $compiled_code .= "<?php\n\n";
-            $compiled_code .= "/* End inline template \"{$sourceInfo}\" =============================*/\n";
+            $compiled_code .= $compiler->cStyleComment(" End inline template \"{$sourceInfo}\" =============================") . "\n";
             $compiled_code .= '?>';
             unset($tpl->compiler);
             if ($tpl->compiled->has_nocache_code) {

libs/sysplugins/smarty_internal_config_file_compiler.php

@@ -157,10 +157,12 @@ class Smarty_Internal_Config_File_Compiler
             $this->smarty->_debug->end_compile($this->template);
         }
         // template header code
-        $template_header =
+        $template_header = sprintf(
-            "<?php /* Smarty version " . Smarty::SMARTY_VERSION . ", created on " . strftime("%Y-%m-%d %H:%M:%S") .
+            "<?php /* Smarty version %s, created on %s\n         compiled from '%s' */ ?>\n",
-            "\n";
+            Smarty::SMARTY_VERSION,
-        $template_header .= "         compiled from '{$this->template->source->filepath}' */ ?>\n";
+            date("Y-m-d H:i:s"),
+            str_replace('*/', '* /' , $this->template->source->filepath)
+        );
         $code = '<?php $_smarty_tpl->smarty->ext->configLoad->_loadConfigVars($_smarty_tpl, ' .
                 var_export($this->config_data, true) . '); ?>';
         return $template_header . $this->template->smarty->ext->_codeFrame->create($this->template, $code);

libs/sysplugins/smarty_internal_runtime_codeframe.php

@@ -44,9 +44,12 @@ class Smarty_Internal_Runtime_CodeFrame
             $properties[ 'file_dependency' ] = $_template->cached->file_dependency;
             $properties[ 'cache_lifetime' ] = $_template->cache_lifetime;
         }
-        $output = "<?php\n";
+        $output = sprintf(
-        $output .= "/* Smarty version {$properties[ 'version' ]}, created on " . strftime("%Y-%m-%d %H:%M:%S") .
+            "<?php\n/* Smarty version %s, created on %s\n  from '%s' */\n\n",
-                   "\n  from '" . str_replace('*/', '* /', $_template->source->filepath) . "' */\n\n";
+            $properties[ 'version' ],
+            date("Y-m-d H:i:s"),
+            str_replace('*/', '* /', $_template->source->filepath)
+        );
         $output .= "/* @var Smarty_Internal_Template \$_smarty_tpl */\n";
         $dec = "\$_smarty_tpl->_decodeProperties(\$_smarty_tpl, " . var_export($properties, true) . ',' .
                ($cache ? 'true' : 'false') . ')';

libs/sysplugins/smarty_internal_templatecompilerbase.php

@@ -1455,6 +1455,10 @@ abstract class Smarty_Internal_TemplateCompilerBase
      */
     abstract protected function doCompile($_content, $isTemplateSource = false);
 
+    public function cStyleComment($string) {
+        return '/*' . str_replace('*/', '* /' , $string) . '*/';
+    }
+
     /**
      * Compile Tag
      *

libs/sysplugins/smarty_internal_templateparser.php

@@ -2837,6 +2837,10 @@ class Smarty_Internal_Templateparser
     // line 765 "../smarty/lexer/smarty_internal_templateparser.y"
     public function yy_r95()
     {
+        if ($this->security && $this->security->static_classes !== array()) {
+            $this->compiler->trigger_template_error('dynamic static class not allowed by security setting');
+        }
+
         $prefixVar = $this->compiler->getNewPrefixVariable();
         if ($this->yystack[ $this->yyidx + -2 ]->minor[ 'var' ] === '\'smarty\'') {
             $this->compiler->appendPrefixCode("<?php {$prefixVar} = " .

make-release.sh

@@ -1,6 +1,11 @@
 #!/bin/bash
 
-printf 'Creating release %s\n' "$1"
+if [[ "$1" =~ ^3\.[0-9\.-rc]+$ ]]; then
+   printf 'Creating release %s\n' "$1"
+else
+   echo "Invalid version number: $1. This script can only make v3.x.x releases."
+   exit 1;
+fi
 
 git checkout -b "release/$1"
 sed -i "s/## \\[Unreleased\\]/## \\[Unreleased\\]\\n\\n## \\[$1\\] - $(date +%Y-%m-%d)/" CHANGELOG.md
@@ -9,11 +14,13 @@ sed -i "s/const SMARTY_VERSION = '[^']\+';/const SMARTY_VERSION = '$1';/" libs/S
 git add CHANGELOG.md libs/Smarty.class.php
 git commit -m "version bump"
 
-git checkout master
+git checkout support/3.1
 git pull
 git merge --no-ff "release/$1"
 git branch -d "release/$1"
 git tag -a "v$1" -m "Release $1"
 
 printf 'Done creating release %s\n' "$1"
+
+# shellcheck disable=SC2016
 printf 'Run `git push --follow-tags origin` to publish it.\n'

tests/UnitTests/SecurityTests/SecurityTest.php

@@ -298,18 +298,38 @@ class SecurityTest extends PHPUnit_Smarty
         $this->assertEquals('25', $this->smarty->fetch($tpl));
     }
 
-/**
+	/**
- * test not trusted PHP function
+	 * test not trusted PHP function
-  * @expectedException        SmartyException
+	 * @expectedException        SmartyException
-  * @expectedExceptionMessage   access to static class 'mysecuritystaticclass' not allowed by security setting
+	 * @expectedExceptionMessage   access to static class 'mysecuritystaticclass' not allowed by security setting
-  * @runInSeparateProcess
+	 */
-  * @preserveGlobalState disabled
+	public function testNotTrustedStaticClass()
-  */
+	{
-    public function testNotTrustedStaticClass()
+		$this->smarty->security_policy->static_classes = array('null');
-    {
+		$this->smarty->fetch('string:{mysecuritystaticclass::square(5)}');
-        $this->smarty->security_policy->static_classes = array('null');
+	}
-            $this->smarty->fetch('string:{mysecuritystaticclass::square(5)}');
+
-    }
+	/**
+	 * test not trusted PHP function
+	 * @expectedException        SmartyException
+	 * @expectedExceptionMessage   dynamic static class not allowed by security setting
+	 */
+	public function testNotTrustedStaticClassEval()
+	{
+		$this->smarty->security_policy->static_classes = array('null');
+		$this->smarty->fetch('string:{$test = "mysecuritystaticclass"}{$test::square(5)}');
+	}
+
+	/**
+	 * test not trusted PHP function
+	 * @expectedException        SmartyException
+	 * @expectedExceptionMessage   dynamic static class not allowed by security setting
+	 */
+	public function testNotTrustedStaticClassSmartyVar()
+	{
+		$this->smarty->security_policy->static_classes = array('null');
+		$this->smarty->fetch('string:{$smarty.template_object::square(5)}');
+	}
 
     public function testChangedTrustedDirectory()
     {

tests/UnitTests/TemplateSource/TagTests/PluginFunction/PluginFunctionMailtoTest.php

@@ -54,7 +54,7 @@ class PluginFunctionMailtoTest extends PHPUnit_Smarty
 
     public function testEncodeJavascript()
     {
-        $result = '<script type="text/javascript">eval(unescape(\'%64%6f%63%75%6d%65%6e%74%2e%77%72%69%74%65%28%27%3c%61%20%68%72%65%66%3d%22%6d%61%69%6c%74%6f%3a%6d%65%40%65%78%61%6d%70%6c%65%2e%63%6f%6d%22%20%3e%6d%65%40%65%78%61%6d%70%6c%65%2e%63%6f%6d%3c%2f%61%3e%27%29%3b\'))</script>';
+        $result = '<script type="text/javascript">document.write(unescape(\'%3c%61%20%68%72%65%66%3d%22%6d%61%69%6c%74%6f%3a%6d%65%40%65%78%61%6d%70%6c%65%2e%63%6f%6d%22%20%3e%6d%65%40%65%78%61%6d%70%6c%65%2e%63%6f%6d%3c%2f%61%3e\'))</script>';
         $tpl = $this->smarty->createTemplate('eval:{mailto address="me@example.com" encode="javascript"}');
         $this->assertEquals(str_replace("\r", '', $result), $this->smarty->fetch($tpl));
     }
@@ -62,7 +62,7 @@ class PluginFunctionMailtoTest extends PHPUnit_Smarty
     public function testEncodeJavascriptWithoutMbstring()
     {
         Smarty::$_MBSTRING = false;
-        $result = '<script type="text/javascript">eval(unescape(\'%64%6f%63%75%6d%65%6e%74%2e%77%72%69%74%65%28%27%3c%61%20%68%72%65%66%3d%22%6d%61%69%6c%74%6f%3a%6d%65%40%65%78%61%6d%70%6c%65%2e%63%6f%6d%22%20%3e%6d%65%40%65%78%61%6d%70%6c%65%2e%63%6f%6d%3c%2f%61%3e%27%29%3b\'))</script>';
+        $result = '<script type="text/javascript">document.write(unescape(\'%3c%61%20%68%72%65%66%3d%22%6d%61%69%6c%74%6f%3a%6d%65%40%65%78%61%6d%70%6c%65%2e%63%6f%6d%22%20%3e%6d%65%40%65%78%61%6d%70%6c%65%2e%63%6f%6d%3c%2f%61%3e\'))</script>';
         $tpl = $this->smarty->createTemplate('eval:{mailto address="me@example.com" encode="javascript"}');
         $this->assertEquals(str_replace("\r", '', $result), $this->smarty->fetch($tpl));
         Smarty::$_MBSTRING = true;
@@ -70,7 +70,7 @@ class PluginFunctionMailtoTest extends PHPUnit_Smarty
 
     public function testEncodeJavascriptCharcode()
     {
-        $result = "<script type=\"text/javascript\" language=\"javascript\">\n{document.write(String.fromCharCode(60,97,32,104,114,101,102,61,34,109,97,105,108,116,111,58,109,101,64,101,120,97,109,112,108,101,46,99,111,109,34,32,62,109,101,64,101,120,97,109,112,108,101,46,99,111,109,60,47,97,62))}\n</script>\n";
+        $result = '<script type="text/javascript">document.write(String.fromCharCode(60,97,32,104,114,101,102,61,34,109,97,105,108,116,111,58,109,101,64,101,120,97,109,112,108,101,46,99,111,109,34,32,62,109,101,64,101,120,97,109,112,108,101,46,99,111,109,60,47,97,62))</script>';
         $tpl = $this->smarty->createTemplate('eval:{mailto address="me@example.com" encode="javascript_charcode"}');
         $this->assertEquals(str_replace("\r", '', $result), $this->smarty->fetch($tpl));
     }
@@ -78,7 +78,7 @@ class PluginFunctionMailtoTest extends PHPUnit_Smarty
     public function testEncodeJavascriptCharcodeWithoutMbstring()
     {
         Smarty::$_MBSTRING = false;
-        $result = "<script type=\"text/javascript\" language=\"javascript\">\n{document.write(String.fromCharCode(60,97,32,104,114,101,102,61,34,109,97,105,108,116,111,58,109,101,64,101,120,97,109,112,108,101,46,99,111,109,34,32,62,109,101,64,101,120,97,109,112,108,101,46,99,111,109,60,47,97,62))}\n</script>\n";
+        $result = '<script type="text/javascript">document.write(String.fromCharCode(60,97,32,104,114,101,102,61,34,109,97,105,108,116,111,58,109,101,64,101,120,97,109,112,108,101,46,99,111,109,34,32,62,109,101,64,101,120,97,109,112,108,101,46,99,111,109,60,47,97,62))</script>';
         $tpl = $this->smarty->createTemplate('eval:{mailto address="me@example.com" encode="javascript_charcode"}');
         $this->assertEquals(str_replace("\r", '', $result), $this->smarty->fetch($tpl));
         Smarty::$_MBSTRING = true;

tests/UnitTests/TemplateSource/ValueTests/Math/MathTest.php

@@ -44,6 +44,30 @@ class MathTest extends PHPUnit_Smarty
         $this->assertEquals($expected, $this->smarty->fetch($tpl));
     }
 
+    public function testMultipleOperators()
+    {
+        $this->smarty->disableSecurity();
+        $expected = "2 -- 2";
+        $tpl = $this->smarty->createTemplate('eval:{$x = 5}{$y = 4}{math equation="x - y + 1" x=$x y=$y} -- {math equation="5 - 4 + 1"}');
+        $this->assertEquals($expected, $this->smarty->fetch($tpl));
+    }
+
+    public function testMathMaxFunctionParameters()
+    {
+        $this->smarty->disableSecurity();
+        $expected = max(0, 2) . ' -- ' . max(0, 2, 3);
+        $tpl = $this->smarty->createTemplate('eval:{$x = 0}{$y = 2}{$z = 3}{math equation="max(x, y)" x=$x y=$y} -- {math equation="max(x, y, z)" x=$x y=$y z=$z}');
+        $this->assertEquals($expected, $this->smarty->fetch($tpl));
+    }
+
+    public function testMathMinFunctionParameters()
+    {
+        $this->smarty->disableSecurity();
+        $expected = min(1, 2) . ' -- ' . min(1, 2, 0);
+        $tpl = $this->smarty->createTemplate('eval:{$x = 1}{$y = 2}{$z = 0}{math equation="min(x, y)" x=$x y=$y} -- {math equation="min(x, y, z)" x=$x y=$y z=$z}');
+        $this->assertEquals($expected, $this->smarty->fetch($tpl));
+    }
+
     public function testSyntaxSin()
     {
         $this->smarty->disableSecurity();
@@ -107,4 +131,35 @@ class MathTest extends PHPUnit_Smarty
         $tpl = $this->smarty->createTemplate('eval:{$x = "4"}{$y = "5.5"}{math equation="x * y" x=$x y=$y format="%0.2f"} -- {math equation="20.5 / 5" format="%0.2f"}');
         $this->assertEquals($expected, $this->smarty->fetch($tpl));
     }
+
+	/**
+	 * @expectedException PHPUnit_Framework_Error_Warning
+	 */
+	public function testBackticksIllegal()
+	{
+		$expected = "22.00";
+		$tpl = $this->smarty->createTemplate('eval:{$x = "4"}{$y = "5.5"}{math equation="`ls` x * y" x=$x y=$y}');
+		$this->assertEquals($expected, $this->smarty->fetch($tpl));
+	}
+
+	/**
+	 * @expectedException PHPUnit_Framework_Error_Warning
+	 */
+	public function testDollarSignsIllegal()
+	{
+		$expected = "22.00";
+		$tpl = $this->smarty->createTemplate('eval:{$x = "4"}{$y = "5.5"}{math equation="$" x=$x y=$y}');
+		$this->assertEquals($expected, $this->smarty->fetch($tpl));
+	}
+
+	/**
+	 * @expectedException PHPUnit_Framework_Error_Warning
+	 */
+	public function testBracketsIllegal()
+	{
+		$expected = "I";
+		$tpl = $this->smarty->createTemplate('eval:{$x = "0"}{$y = "1"}{math equation="((y/x).(x))[x]" x=$x y=$y}');
+		$this->assertEquals($expected, $this->smarty->fetch($tpl));
+	}
+
 }