Extend zend guards to allow recursion protection

Author: bukka

Zend/zend_API.c

@@ -2746,6 +2746,7 @@ ZEND_API void zend_add_magic_method(zend_class_entry *ce, zend_function *fptr, z
 		ce->__tostring = fptr;
 	} else if (zend_string_equals_literal(lcname, ZEND_DEBUGINFO_FUNC_NAME)) {
 		ce->__debugInfo = fptr;
+		ce->ce_flags |= ZEND_ACC_USE_GUARDS;
 	} else if (zend_string_equals_literal(lcname, "__serialize")) {
 		ce->__serialize = fptr;
 	} else if (zend_string_equals_literal(lcname, "__unserialize")) {

Zend/zend_object_handlers.c

@@ -36,10 +36,10 @@
 #define ZEND_WRONG_PROPERTY_OFFSET   0
 
 /* guard flags */
-#define IN_GET		(1<<0)
-#define IN_SET		(1<<1)
-#define IN_UNSET	(1<<2)
-#define IN_ISSET	(1<<3)
+#define IN_GET		ZEND_GUARD_PROPERTY_GET
+#define IN_SET		ZEND_GUARD_PROPERTY_SET
+#define IN_UNSET	ZEND_GUARD_PROPERTY_UNSET
+#define IN_ISSET	ZEND_GUARD_PROPERTY_ISSET
 
 /*
   __X accessors explanation:
@@ -555,17 +555,17 @@ ZEND_API uint32_t *zend_get_property_guard(zend_object *zobj, zend_string *membe
 		if (EXPECTED(str == member) ||
 		    /* str and member don't necessarily have a pre-calculated hash value here */
 		    EXPECTED(zend_string_equal_content(str, member))) {
-			return &Z_PROPERTY_GUARD_P(zv);
-		} else if (EXPECTED(Z_PROPERTY_GUARD_P(zv) == 0)) {
+			return &Z_GUARD_P(zv);
+		} else if (EXPECTED(Z_GUARD_P(zv) == 0)) {
 			zval_ptr_dtor_str(zv);
 			ZVAL_STR_COPY(zv, member);
-			return &Z_PROPERTY_GUARD_P(zv);
+			return &Z_GUARD_P(zv);
 		} else {
 			ALLOC_HASHTABLE(guards);
 			zend_hash_init(guards, 8, NULL, zend_property_guard_dtor, 0);
 			/* mark pointer as "special" using low bit */
 			zend_hash_add_new_ptr(guards, str,
-				(void*)(((uintptr_t)&Z_PROPERTY_GUARD_P(zv)) | 1));
+				(void*)(((uintptr_t)&Z_GUARD_P(zv)) | 1));
 			zval_ptr_dtor_str(zv);
 			ZVAL_ARR(zv, guards);
 		}
@@ -579,8 +579,8 @@ ZEND_API uint32_t *zend_get_property_guard(zend_object *zobj, zend_string *membe
 	} else {
 		ZEND_ASSERT(Z_TYPE_P(zv) == IS_UNDEF);
 		ZVAL_STR_COPY(zv, member);
-		Z_PROPERTY_GUARD_P(zv) = 0;
-		return &Z_PROPERTY_GUARD_P(zv);
+		Z_GUARD_P(zv) &= ~ZEND_GUARD_PROPERTY_MASK;
+		return &Z_GUARD_P(zv);
 	}
 	/* we have to allocate uint32_t separately because ht->arData may be reallocated */
 	ptr = (uint32_t*)emalloc(sizeof(uint32_t));

Zend/zend_types.h

@@ -345,7 +345,7 @@ struct _zval_struct {
 		uint32_t     num_args;             /* arguments number for EX(This) */
 		uint32_t     fe_pos;               /* foreach position */
 		uint32_t     fe_iter_idx;          /* foreach iterator index */
-		uint32_t     property_guard;       /* single property guard */
+		uint32_t     guard;                /* recursion and single property guard */
 		uint32_t     constant_flags;       /* constant flags */
 		uint32_t     extra;                /* not further specified */
 	} u2;
@@ -619,6 +619,15 @@ struct _zend_ast_ref {
 #define _IS_BOOL					18
 #define _IS_NUMBER					19
 
+/* guard flags */
+#define ZEND_GUARD_PROPERTY_GET		(1<<0)
+#define ZEND_GUARD_PROPERTY_SET		(1<<1)
+#define ZEND_GUARD_PROPERTY_UNSET	(1<<2)
+#define ZEND_GUARD_PROPERTY_ISSET	(1<<3)
+#define ZEND_GUARD_PROPERTY_MASK	15
+#define ZEND_GUARD_RECURSION_DEBUG	(1<<4)
+#define ZEND_GUARD_RECURSION_JSON	(1<<5)
+
 static zend_always_inline uint8_t zval_get_type(const zval* pz) {
 	return pz->u1.v.type;
 }
@@ -659,8 +668,8 @@ static zend_always_inline uint8_t zval_get_type(const zval* pz) {
 #define Z_FE_ITER(zval)				(zval).u2.fe_iter_idx
 #define Z_FE_ITER_P(zval_p)			Z_FE_ITER(*(zval_p))
 
-#define Z_PROPERTY_GUARD(zval)		(zval).u2.property_guard
-#define Z_PROPERTY_GUARD_P(zval_p)	Z_PROPERTY_GUARD(*(zval_p))
+#define Z_GUARD(zval)				(zval).u2.guard
+#define Z_GUARD_P(zval_p)			Z_GUARD(*(zval_p))
 
 #define Z_CONSTANT_FLAGS(zval)		(zval).u2.constant_flags
 #define Z_CONSTANT_FLAGS_P(zval_p)	Z_CONSTANT_FLAGS(*(zval_p))

ext/json/json.c

@@ -37,10 +37,17 @@ PHP_JSON_API zend_class_entry *php_json_exception_ce;
 
 PHP_JSON_API ZEND_DECLARE_MODULE_GLOBALS(json)
 
+static int php_json_implement_json_serializable(zend_class_entry *interface, zend_class_entry *class_type)
+{
+	class_type->ce_flags |= ZEND_ACC_USE_GUARDS;
+	return SUCCESS;
+}
+
 /* {{{ MINIT */
 static PHP_MINIT_FUNCTION(json)
 {
 	php_json_serializable_ce = register_class_JsonSerializable();
+	php_json_serializable_ce->interface_gets_implemented = php_json_implement_json_serializable;
 
 	php_json_exception_ce = register_class_JsonException(zend_ce_exception);