Add missing NULL pointer checks related to the previous call frame

Author: ndossche

Zend/zend_builtin_functions.c

@@ -154,7 +154,7 @@ ZEND_FUNCTION(func_num_args)
 
 	ZEND_PARSE_PARAMETERS_NONE();
 
-	if (ZEND_CALL_INFO(ex) & ZEND_CALL_CODE) {
+	if (ex && (ZEND_CALL_INFO(ex) & ZEND_CALL_CODE)) {
 		zend_throw_error(NULL, "func_num_args() must be called from a function context");
 		RETURN_THROWS();
 	}
@@ -185,7 +185,7 @@ ZEND_FUNCTION(func_get_arg)
 	}
 
 	ex = EX(prev_execute_data);
-	if (ZEND_CALL_INFO(ex) & ZEND_CALL_CODE) {
+	if (ex && (ZEND_CALL_INFO(ex) & ZEND_CALL_CODE)) {
 		zend_throw_error(NULL, "func_get_arg() cannot be called from the global scope");
 		RETURN_THROWS();
 	}
@@ -223,7 +223,7 @@ ZEND_FUNCTION(func_get_args)
 
 	ZEND_PARSE_PARAMETERS_NONE();
 
-	if (ZEND_CALL_INFO(ex) & ZEND_CALL_CODE) {
+	if (ex && (ZEND_CALL_INFO(ex) & ZEND_CALL_CODE)) {
 		zend_throw_error(NULL, "func_get_args() cannot be called from the global scope");
 		RETURN_THROWS();
 	}

ext/standard/basic_functions.c

@@ -1541,7 +1541,7 @@ PHP_FUNCTION(forward_static_call)
 		Z_PARAM_VARIADIC('*', fci.params, fci.param_count)
 	ZEND_PARSE_PARAMETERS_END();
 
-	if (!EX(prev_execute_data)->func->common.scope) {
+	if (!EX(prev_execute_data) || !EX(prev_execute_data)->func->common.scope) {
 		zend_throw_error(NULL, "Cannot call forward_static_call() when no class scope is active");
 		RETURN_THROWS();
 	}

ext/standard/tests/general_functions/register_shutdown_functions_without_previous_call_frame_01.phpt

@@ -0,0 +1,15 @@
+--TEST--
+register_shutdown_function() without a previous call frame 01
+--FILE--
+<?php
+register_shutdown_function("forward_static_call", "hash_hkdf");
+?>
+Done
+--EXPECT--
+Done
+
+Fatal error: Uncaught Error: Cannot call forward_static_call() when no class scope is active in [no active file]:0
+Stack trace:
+#0 [internal function]: forward_static_call('hash_hkdf')
+#1 {main}
+  thrown in [no active file] on line 0

ext/standard/tests/general_functions/register_shutdown_functions_without_previous_call_frame_02.phpt

@@ -0,0 +1,15 @@
+--TEST--
+register_shutdown_function() without a previous call frame 02
+--FILE--
+<?php
+register_shutdown_function("func_get_args");
+?>
+Done
+--EXPECT--
+Done
+
+Fatal error: Uncaught Error: Cannot call func_get_args() dynamically in [no active file]:0
+Stack trace:
+#0 [internal function]: func_get_args()
+#1 {main}
+  thrown in [no active file] on line 0

ext/standard/tests/general_functions/register_shutdown_functions_without_previous_call_frame_03.phpt

@@ -0,0 +1,15 @@
+--TEST--
+register_shutdown_function() without a previous call frame 03
+--FILE--
+<?php
+register_shutdown_function("func_num_args");
+?>
+Done
+--EXPECT--
+Done
+
+Fatal error: Uncaught Error: Cannot call func_num_args() dynamically in [no active file]:0
+Stack trace:
+#0 [internal function]: func_num_args()
+#1 {main}
+  thrown in [no active file] on line 0

ext/standard/tests/general_functions/register_shutdown_functions_without_previous_call_frame_04.phpt

@@ -0,0 +1,15 @@
+--TEST--
+register_shutdown_function() without a previous call frame 04
+--FILE--
+<?php
+register_shutdown_function("func_get_arg");
+?>
+Done
+--EXPECT--
+Done
+
+Fatal error: Uncaught ArgumentCountError: func_get_arg() expects exactly 1 argument, 0 given in [no active file]:0
+Stack trace:
+#0 [internal function]: func_get_arg()
+#1 {main}
+  thrown in [no active file] on line 0