Fix comp-time and constant evaluation of dynamic class constant fetch

Fixes GH-10486
Fixes oss-fuzz #55436
Fixes oss-fuzz #55472

Author: iluuu1994

Zend/tests/gh10486.phpt

@@ -0,0 +1,11 @@
+--TEST--
+Assertion error when attempting comp-time eval of dynamic class constant fetch
+--FILE--
+<?php
+y::{5}::y;
+?>
+--EXPECTF--
+Fatal error: Uncaught Error: Class "y" not found in %s:%d
+Stack trace:
+#0 {main}
+  thrown in %s on line %d

Zend/tests/gh10486_2.phpt

@@ -0,0 +1,11 @@
+--TEST--
+Assertion error when attempting constant eval of dynamic class constant fetch
+--FILE--
+<?php
+const y = y::{y};
+?>
+--EXPECTF--
+Fatal error: Uncaught Error: Undefined constant "y" in %s:%d
+Stack trace:
+#0 {main}
+  thrown in %s on line %d

Zend/zend_ast.c

@@ -803,7 +803,15 @@ ZEND_API zend_result ZEND_FASTCALL zend_ast_evaluate_ex(
 		case ZEND_AST_CLASS_CONST:
 		{
 			zend_string *class_name = zend_ast_get_str(ast->child[0]);
-			zend_string *const_name = zend_ast_get_str(ast->child[1]);
+			if (UNEXPECTED(zend_ast_evaluate_ex(&op2, ast->child[1], scope, &short_circuited, ctx) != SUCCESS)) {
+				return FAILURE;
+			}
+			if (UNEXPECTED(Z_TYPE(op2) != IS_STRING)) {
+				zend_invalid_class_constant_type_error(Z_TYPE(op2));
+				zval_ptr_dtor_nogc(&op2);
+				return FAILURE;
+			}
+			zend_string *const_name = Z_STR(op2);
 
 			zend_string *previous_filename;
 			zend_long previous_lineno;
@@ -821,9 +829,11 @@ ZEND_API zend_result ZEND_FASTCALL zend_ast_evaluate_ex(
 
 			if (UNEXPECTED(zv == NULL)) {
 				ZVAL_UNDEF(result);
+				zval_ptr_dtor_nogc(&op2);
 				return FAILURE;
 			}
 			ZVAL_COPY_OR_DUP(result, zv);
+			zval_ptr_dtor_nogc(&op2);
 			break;
 		}
 		case ZEND_AST_NEW:

Zend/zend_compile.c

@@ -10742,6 +10742,11 @@ static void zend_eval_const_expr(zend_ast **ast_ptr) /* {{{ */
 			zend_ast *name_ast;
 			zend_string *resolved_name;
 
+			if (UNEXPECTED(ast->child[1]->kind != ZEND_AST_ZVAL
+				|| Z_TYPE_P(zend_ast_get_zval(ast->child[1])) != IS_STRING)) {
+				return;
+			}
+
 			zend_eval_const_expr(&ast->child[0]);
 			zend_eval_const_expr(&ast->child[1]);
 

Zend/zend_execute.c

@@ -894,6 +894,11 @@ ZEND_API ZEND_COLD void ZEND_FASTCALL zend_readonly_property_indirect_modificati
 		ZSTR_VAL(info->ce->name), zend_get_unmangled_property_name(info->name));
 }
 
+ZEND_API ZEND_COLD void ZEND_FASTCALL zend_invalid_class_constant_type_error(zend_uchar type)
+{
+	zend_type_error("Cannot use value of type %s as class constant name", zend_get_type_by_const(type));
+}
+
 static const zend_class_entry *resolve_single_class_type(zend_string *name, const zend_class_entry *self_ce) {
 	if (zend_string_equals_literal_ci(name, "self")) {
 		return self_ce;

Zend/zend_execute.h

@@ -82,6 +82,8 @@ ZEND_API ZEND_COLD void zend_wrong_string_offset_error(void);
 ZEND_API ZEND_COLD void ZEND_FASTCALL zend_readonly_property_modification_error(const zend_property_info *info);
 ZEND_API ZEND_COLD void ZEND_FASTCALL zend_readonly_property_indirect_modification_error(const zend_property_info *info);
 
+ZEND_API ZEND_COLD void ZEND_FASTCALL zend_invalid_class_constant_type_error(zend_uchar type);
+
 ZEND_API bool zend_verify_scalar_type_hint(uint32_t type_mask, zval *arg, bool strict, bool is_internal_arg);
 ZEND_API ZEND_COLD void zend_verify_arg_error(
 		const zend_function *zf, const zend_arg_info *arg_info, uint32_t arg_num, zval *value);

Zend/zend_vm_def.h

@@ -5922,7 +5922,7 @@ ZEND_VM_HANDLER(181, ZEND_FETCH_CLASS_CONSTANT, VAR|CONST|UNUSED|CLASS_FETCH, CO
 
 		constant_zv = GET_OP2_ZVAL_PTR_DEREF(BP_VAR_R);
 		if (UNEXPECTED(Z_TYPE_P(constant_zv) != IS_STRING)) {
-			zend_type_error("Cannot use value of type %s as class constant name", zend_get_type_by_const(Z_TYPE_P(constant_zv)));
+			zend_invalid_class_constant_type_error(Z_TYPE_P(constant_zv));
 			ZVAL_UNDEF(EX_VAR(opline->result.var));
 			FREE_OP2();
 			HANDLE_EXCEPTION();