[RFC PATCH 0/3] Improved ALSR

[Szabolcs Nagy]

The 11/23/2020 20:16, Topi Miettinen via Libc-alpha wrote:
> On 23.11.2020 18.44, Florian Weimer wrote:
> > And the series only changes the TCB allocation for the main thread.
> > Fixing thread TCB/stack collocation is a completely different matter
> > (and probably the more significant issue than lack of ASLR).
> 
> I thought I covered all uses of sbrk(), perhaps I missed that one. Does the
> thread TCB/stack allocation use sbrk()?

the point is that thread stack and tls is allocated
as one block (with mmap, but that does not matter).

you want at least a guard page in between, so stack
corruption does not clobber tcb/tls data.

but this has costs (kernel side vma) and significant
work in glibc (separate tls and stack size accounting).