Security policy wildcard support for methods/properties

src/Sandbox/MemberMatcher.php

@@ -0,0 +1,79 @@
+<?php
+
+/*
+ * This file is part of Twig.
+ *
+ * (c) Fabien Potencier
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Twig\Sandbox;
+
+/**
+ * Allows for flexible wildcard support in allowedMethods and allowedProperties in SecurityPolicy.
+ * - Class can be specified as wildcard `* => [...]` in order to allow those methods/properties for all classes.
+ * - Method/property can be specified as wildcard eg. `\DateTime => '*'` in order to allow all methods/properties for that class.
+ * - Method/property can also be specified with a trailing wildcard to allow all methods/properties with a certain prefix, eg. `\DateTime => ['get*', ...]` in order to allow all methods/properties that start with `get`.
+ *
+ * @author Yaakov Saxon <ysaxon@gmail.com>
+ */
+final class MemberMatcher
+{
+    private $allowedMembers;
+    private $cache = [];
+
+    public function __construct(array $allowedMembers)
+    {
+        $normalizedMembers = [];
+        foreach ($allowedMembers as $class => $members) {
+            if (!\is_array($members)) {
+                $normalizedMembers[$class][] = strtolower($members);
+            } else {
+                foreach ($members as $index => $member) {
+                    $normalizedMembers[$class][$index] = strtolower($member);
+                }
+            }
+        }
+        $this->allowedMembers = $normalizedMembers;
+    }
+
+    public function isAllowed($obj, string $member): bool
+    {
+        $cacheKey = get_class($obj) . "::" . $member;
+
+        // Check cache first
+        if (isset($this->cache[$cacheKey])) {
+            return true;
+        }
+
+        $member = strtolower($member); // normalize member name
+
+        foreach ($this->allowedMembers as $class => $members) {
+            if ('*' === $class || $obj instanceof $class) {
+                foreach ($members as $allowedMember) {
+                    if ('*' === $allowedMember) {
+                        $this->cache[$cacheKey] = true;
+
+                        return true;
+                    }
+                    if ($allowedMember === $member) {
+                        $this->cache[$cacheKey] = true;
+
+                        return true;
+                    }
+                    // if allowedMember ends with a *, check if the member starts with the allowedMember
+                    if ('*' === substr($allowedMember, -1) && substr($member, 0, \strlen($allowedMember) - 1) === rtrim($allowedMember, '*')) {
+                        $this->cache[$cacheKey] = true;
+
+                        return true;
+                    }
+                }
+            }
+        }
+
+        // If we reach here, the member is not allowed
+        return false;
+    }
+}

src/Sandbox/SecurityPolicy.php

@@ -32,7 +32,7 @@ public function __construct(array $allowedTags = [], array $allowedFilters = [],
         $this->allowedTags = $allowedTags;
         $this->allowedFilters = $allowedFilters;
         $this->setAllowedMethods($allowedMethods);
-        $this->allowedProperties = $allowedProperties;
+        $this->setAllowedProperties($allowedProperties);
         $this->allowedFunctions = $allowedFunctions;
     }
 
@@ -48,15 +48,12 @@ public function setAllowedFilters(array $filters)
 
     public function setAllowedMethods(array $methods)
     {
-        $this->allowedMethods = [];
-        foreach ($methods as $class => $m) {
-            $this->allowedMethods[$class] = array_map(function ($value) { return strtr($value, 'ABCDEFGHIJKLMNOPQRSTUVWXYZ', 'abcdefghijklmnopqrstuvwxyz'); }, \is_array($m) ? $m : [$m]);
-        }
+        $this->allowedMethods = new MemberMatcher($methods);
     }
 
     public function setAllowedProperties(array $properties)
     {
-        $this->allowedProperties = $properties;
+        $this->allowedProperties = new MemberMatcher($properties);
     }
 
     public function setAllowedFunctions(array $functions)
@@ -91,32 +88,16 @@ public function checkMethodAllowed($obj, $method)
             return;
         }
 
-        $allowed = false;
-        $method = strtr($method, 'ABCDEFGHIJKLMNOPQRSTUVWXYZ', 'abcdefghijklmnopqrstuvwxyz');
-        foreach ($this->allowedMethods as $class => $methods) {
-            if ($obj instanceof $class && \in_array($method, $methods)) {
-                $allowed = true;
-                break;
-            }
-        }
-
-        if (!$allowed) {
+        if (!$this->allowedMethods->isAllowed($obj, $method)) {
             $class = \get_class($obj);
+            $method = strtr($method, 'ABCDEFGHIJKLMNOPQRSTUVWXYZ', 'abcdefghijklmnopqrstuvwxyz');
             throw new SecurityNotAllowedMethodError(sprintf('Calling "%s" method on a "%s" object is not allowed.', $method, $class), $class, $method);
         }
     }
 
     public function checkPropertyAllowed($obj, $property)
     {
-        $allowed = false;
-        foreach ($this->allowedProperties as $class => $properties) {
-            if ($obj instanceof $class && \in_array($property, \is_array($properties) ? $properties : [$properties])) {
-                $allowed = true;
-                break;
-            }
-        }
-
-        if (!$allowed) {
+        if (!$this->allowedProperties->isAllowed($obj, $property)) {
             $class = \get_class($obj);
             throw new SecurityNotAllowedPropertyError(sprintf('Calling "%s" property on a "%s" object is not allowed.', $property, $class), $class, $property);
         }

tests/Extension/SandboxTest.php

@@ -449,6 +449,87 @@ public function testMultipleClassMatchesViaInheritanceInAllowedMethods()
         }
     }
 
+    public function testSandboxAllowedWildcardMethod()
+    {
+        $allowedMethods = ['Twig\Tests\Extension\FooObject' => ['*']];
+        $twig = $this->getEnvironment(true, [], self::$templates, [], [], $allowedMethods);
+
+        // This should pass without throwing an exception
+        $result = $twig->load('1_basic1')->render(self::$params);
+        $this->assertEquals('foo', $result);
+        $result = $twig->load('1_basic8')->render(self::$params);
+        $this->assertEquals('foobarfoobar', $result);
+
+    }
+
+    public function testSandboxAllowedWildcardSuffixMethod()
+    {
+        $allowedMethods = ['Twig\Tests\Extension\FooObject' => ['get*']];
+        $twig = $this->getEnvironment(true, [], self::$templates, [], [], $allowedMethods);
+
+        // This should pass without throwing an exception
+        $result = $twig->load('1_basic8')->render(self::$params);
+        $this->assertEquals('foobarfoobar', $result);
+    }
+
+    public function testSandboxUnallowedPrefixWildcardSuffixMethod()
+    {
+        $allowedMethods = ['Twig\Tests\Extension\FooObject' => ['get*']];
+        $twig = $this->getEnvironment(true, [], self::$templates, [], [], $allowedMethods);
+
+        try {
+            $twig->load('1_basic1')->render(self::$params);
+            $this->fail('Sandbox should block method not matching method prefix');
+        } catch (SecurityError $e) {
+            $this->assertInstanceOf(SecurityNotAllowedMethodError::class, $e);
+            $this->assertEquals('foo', $e->getMethodName());
+        }
+    }
+
+    public function testSandboxAllowedWildcardClassMethod()
+    {
+        $allowedMethods = ['*' => ['foo']];
+        $twig = $this->getEnvironment(true, [], self::$templates, [], [], $allowedMethods);
+
+        // This should pass without throwing an exception
+        $result = $twig->load('1_basic1')->render(self::$params);
+        $this->assertEquals('foo', $result);
+    }
+
+    public function testSandboxUnallowedWildcardClassMethod()
+    {
+        $allowedMethods = ['*' => ['foo']];
+        $twig = $this->getEnvironment(true, [], self::$templates, [], [], $allowedMethods);
+
+        try {
+            $twig->load('1_basic8')->render(self::$params);
+            $this->fail('Sandbox should block non matching method despite class wildcard');
+        } catch (SecurityError $e) {
+            $this->assertInstanceOf(SecurityNotAllowedMethodError::class, $e);
+            $this->assertEquals('getfoobar', $e->getMethodName());
+        }
+    }
+
+    public function testSandboxAllowedWildcardClassWildcardSuffixMethod()
+    {
+        $allowedMethods = ['*' => ['get*']];
+        $twig = $this->getEnvironment(true, [], self::$templates, [], [], $allowedMethods);
+
+        // This should pass without throwing an exception
+        $result = $twig->load('1_basic8')->render(self::$params);
+        $this->assertEquals('foobarfoobar', $result);
+    }
+
+    public function testSandboxAllowedWildcardClassWildcardSuffixProperty()
+    {
+        $allowedProperties = ['*' => ['b*']];
+        $twig = $this->getEnvironment(true, [], self::$templates, [], [], [], $allowedProperties);
+
+        // This should pass without throwing an exception
+        $result = $twig->load('1_basic4')->render(self::$params);
+        $this->assertEquals('bar', $result);
+    }
+
     protected function getEnvironment($sandboxed, $options, $templates, $tags = [], $filters = [], $methods = [], $properties = [], $functions = [])
     {
         $loader = new ArrayLoader($templates);