Fixed bug #77632 (FFI Segfaults When Called With Variadics)

Author: dstogov

ext/ffi/ffi.c

@@ -1776,14 +1776,12 @@ static int zend_ffi_cdata_get_closure(zval *obj, zend_class_entry **ce_ptr, zend
 	func->common.arg_flags[2] = 0;
 	func->common.fn_flags = ZEND_ACC_CALL_VIA_TRAMPOLINE;
 	func->common.function_name = ZSTR_KNOWN(ZEND_STR_MAGIC_INVOKE);
-	func->common.num_args = func->common.required_num_args = type->func.args ? zend_hash_num_elements(type->func.args) : 0;
+	/* set to 0 to avoid arg_info[] allocation, because all values are passed by value anyway */
+	func->common.num_args = 0;
+	func->common.required_num_args = type->func.args ? zend_hash_num_elements(type->func.args) : 0;
+	func->common.arg_info = NULL;
 	func->internal_function.handler = ZEND_FN(ffi_trampoline);
 
-	if (func->common.num_args > MAX_ARG_FLAG_NUM) {
-		func->common.arg_info = emalloc(sizeof(zend_arg_info) * func->common.num_args);
-		memset(func->common.arg_info, 0, sizeof(zend_arg_info) * func->common.num_args);
-	}
-
 	func->internal_function.reserved[0] = type;
 	func->internal_function.reserved[1] = *(void**)cdata->ptr;
 
@@ -2447,9 +2445,6 @@ static ZEND_FUNCTION(ffi_trampoline) /* {{{ */
 
 	zend_string_release(EX(func)->common.function_name);
 	if (EX(func)->common.fn_flags & ZEND_ACC_CALL_VIA_TRAMPOLINE) {
-		if (EX(func)->common.arg_info) {
-			efree(EX(func)->common.arg_info);
-		}
 		zend_free_trampoline(EX(func));
 		EX(func) = NULL;
 	}
@@ -2507,14 +2502,12 @@ static zend_function *zend_ffi_get_func(zend_object **obj, zend_string *name, co
 	func->common.arg_flags[2] = 0;
 	func->common.fn_flags = ZEND_ACC_CALL_VIA_TRAMPOLINE;
 	func->common.function_name = zend_string_copy(name);
-	func->common.num_args = func->common.required_num_args = type->func.args ? zend_hash_num_elements(type->func.args) : 0;
+	/* set to 0 to avoid arg_info[] allocation, because all values are passed by value anyway */
+	func->common.num_args = 0;
+	func->common.required_num_args = type->func.args ? zend_hash_num_elements(type->func.args) : 0;
+	func->common.arg_info = NULL;
 	func->internal_function.handler = ZEND_FN(ffi_trampoline);
 
-	if (func->common.num_args > MAX_ARG_FLAG_NUM) {
-		func->common.arg_info = emalloc(sizeof(zend_arg_info) * func->common.num_args);
-		memset(func->common.arg_info, 0, sizeof(zend_arg_info) * func->common.num_args);
-	}
-
 	func->internal_function.reserved[0] = type;
 	func->internal_function.reserved[1] = sym->addr;
 

ext/ffi/tests/bug77632.phpt

@@ -0,0 +1,14 @@
+--TEST--
+Bug #77632 (FFI Segfaults When Called With Variadics)
+--SKIPIF--
+<?php require_once('skipif.inc'); ?>
+--INI--
+ffi.enable=1
+--FILE--
+<?php
+$libc = FFI::cdef("int printf(const char *format, ...);", "libc.so.6");
+$args = ["test\n"];
+$libc->printf(...$args);
+?>
+--EXPECT--
+test