Changelog

Fixes #702.

CHANGELOG.md

@@ -6,6 +6,19 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### 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

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 = '3.1.41';
+    const SMARTY_VERSION = '3.1.43';
     /**
      * define variable scopes
      */

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_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} = " .

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
-  * @expectedException        SmartyException
-  * @expectedExceptionMessage   access to static class 'mysecuritystaticclass' not allowed by security setting
-  * @runInSeparateProcess
-  * @preserveGlobalState disabled
-  */
-    public function testNotTrustedStaticClass()
-    {
-        $this->smarty->security_policy->static_classes = array('null');
-            $this->smarty->fetch('string:{mysecuritystaticclass::square(5)}');
-    }
+	/**
+	 * test not trusted PHP function
+	 * @expectedException        SmartyException
+	 * @expectedExceptionMessage   access to static class 'mysecuritystaticclass' not allowed by security setting
+	 */
+	public function testNotTrustedStaticClass()
+	{
+		$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 +44,14 @@ 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 testSyntaxSin()
     {
         $this->smarty->disableSecurity();
@@ -107,4 +115,35 @@ 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));
+	}
+
 }