On Tue, Mar 23, 2021 at 08:57:42AM -0400, Steven Rostedt wrote: > Well, from what I understand is that typecasting functions to other types > of functions is one of the mistakes that cause security bugs to happen. And > there's been a few of them in the kernel. Which is why the compilers have > now been flagging them.
Doing the cast in the first pace is an indication something weird is happening anyway. C will already warn you if you assign non-matching pointer types. So if there's bugs, audit all (function) pointer casts. Don't wreck casts. This warning will only make people add more (void *) intermediate casts and then we have uglier code and an equal amount of hidden bugs. IE. we really didn't win anything at all. > This particular instance of the typecasting is unique and there's a bit of > magic involved. Adding this little work around here is fine. Probably needs > a better comment though. Nah, it's not unique, static_call() has a whole bunch of them, including the exact same you have. Yes, we're doing something C thinks is UB, but we do that all day every day.