Make RegisterClassExA check that reserved bytes is a valid value.

dlls/user/tests/class.c

@@ -310,6 +310,7 @@ static void test_instances(void)
 
     cls.lpszMenuName  = "main_module";
     cls.hInstance = main_module;
+
     ok( RegisterClassA( &cls ), "Failed to register local class for main module\n" );
     check_class( main_module, name, "main_module" );
     check_instance( name, main_module, main_module, main_module );
@@ -324,6 +325,29 @@ static void test_instances(void)
     check_thread_instance( name, kernel32, kernel32, kernel32 );
     ok( UnregisterClassA( name, kernel32 ), "Unregister failed for kernel32\n" );
 
+    /* Bug 2631 - Supplying an invalid number of bytes fails */
+    cls.cbClsExtra    = 0;
+    cls.cbWndExtra    = -1;
+    SetLastError(0xdeadbeef);
+    ok( ((RegisterClassA( &cls ) == 0) && (GetLastError() == ERROR_INVALID_PARAMETER)),
+          "Failed with invalid number of WndExtra bytes\n");
+
+    cls.cbClsExtra    = -1;
+    cls.cbWndExtra    = 0;
+    SetLastError(0xdeadbeef);
+    ok( ((RegisterClassA( &cls ) == 0) && (GetLastError() == ERROR_INVALID_PARAMETER)),
+          "Failed with invalid number of ClsExtra bytes\n");
+
+    cls.cbClsExtra    = -1;
+    cls.cbWndExtra    = -1;
+    SetLastError(0xdeadbeef);
+    ok( ((RegisterClassA( &cls ) == 0) && (GetLastError() == ERROR_INVALID_PARAMETER)),
+          "Failed with invalid number of ClsExtra and cbWndExtra bytes\n");
+
+    cls.cbClsExtra    = 0;
+    cls.cbWndExtra    = 0;
+    SetLastError(0xdeadbeef);
+
     /* setting global flag doesn't change status of class */
     hwnd = CreateWindowExA( 0, name, "test", 0, 0, 0, 0, 0, 0, 0, main_module, 0 );
     SetClassLongA( hwnd, GCL_STYLE, CS_GLOBALCLASS );

windows/class.c

@@ -379,11 +379,14 @@ static CLASS *CLASS_RegisterClass( ATOM atom, HINSTANCE hInstance, BOOL local,
 
     /* Fix the extra bytes value */
 
-    if (classExtra < 0) classExtra = 0;
-    else if (classExtra > 40)  /* Extra bytes are limited to 40 in Win32 */
+    if (classExtra < 0 || winExtra < 0)
+    {
+         SetLastError( ERROR_INVALID_PARAMETER );
+         return NULL;
+    }
+    if (classExtra > 40)  /* Extra bytes are limited to 40 in Win32 */
         WARN("Class extra bytes %d is > 40\n", classExtra);
-    if (winExtra < 0) winExtra = 0;
-    else if (winExtra > 40)    /* Extra bytes are limited to 40 in Win32 */
+    if (winExtra > 40)    /* Extra bytes are limited to 40 in Win32 */
         WARN("Win extra bytes %d is > 40\n", winExtra );
 
     classPtr = HeapAlloc( GetProcessHeap(), HEAP_ZERO_MEMORY, sizeof(CLASS) + classExtra );