Re: [PATCH 0/3] exec: Pin stack limit during exec

[Kees Cook]

On Tue, Jan 9, 2018 at 12:23 PM, Kees Cook <keescook@xxxxxxxxxxxx> wrote:
> Attempts to solve problems with the stack limit changing during exec
> continue to be frustrated[1][2]. In addition to the specific issues
> around the Stack Clash family of flaws, Andy Lutomirski pointed out[3]
> other places during exec where the stack limit is used and is assumed
> to be unchanging. Given the many places it gets used and the fact that
> it can be manipulated/raced via setrlimit() and prlimit(), I think the
> only way to handle this is to move away from the "current" view of the
> stack limit and instead attach it to the bprm, and plumb this down into
> the functions that need to know the stack limits. This series implements
> the approach. I'd be curious to hear feedback on alternatives.

Friendly ping -- looking for some people with spare cycles to look
this over. If people want, I can toss it into -next as part of my kspp
tree. It's been living happily in 0-day for  2 weeks...

Thanks!

-Kees

> [1] 04e35f4495dd ("exec: avoid RLIMIT_STACK races with prlimit()")
> [2] 779f4e1c6c7c ("Revert "exec: avoid RLIMIT_STACK races with prlimit()"")
> [3] to security@xxxxxxxxxx, "Subject: existing rlimit races?"

-- 
Kees Cook
Pixel Security