[PATCH] malloc/malloc.c: Mitigate null-byte overflow attacks

[Moritz Eckert]

> 
> Sorry, I'm not getting my idea across.  Let me try again.
> 
> I'm thinking, something that tests a size *before* we consider it in the
> context of a chunk, such as this one:
> 
>    https://www.sourceware.org/ml/libc-alpha/2017-10/msg01202.html
> 
> One might also consider certain combinations of the three low order
> bits, like setting both the A (arena) and M (mmap'd) bits at the same
> time.
> 
> Even if we had such a test, though, we'd still need to carefully
> consider all the places we'd use it - comparing possible utility vs
> performance degredation.
> 


Ah I see. That's a good check btw:-)


 > But please don't consider this a requirement for any pending patches, I
 > was just thinking out loud ;-)
 >

So for my current patch idea, would you prefer it with or without a 
macro and keeping the check inside unlink or not?