linux-kernel - Re: [RESEND][PATCH 0/3] exec: Pin stack limit during exec

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Message-ID: <20180220134623.GA21134@dhcp22.suse.cz>
Date:   Tue, 20 Feb 2018 14:46:23 +0100
From:   Michal Hocko <mhocko@...nel.org>
To:     Kees Cook <keescook@...omium.org>
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Ben Hutchings <ben@...adent.org.uk>, Willy Tarreau <w@....eu>,
        Hugh Dickins <hughd@...gle.com>,
        Oleg Nesterov <oleg@...hat.com>,
        "Jason A. Donenfeld" <Jason@...c4.com>,
        Rik van Riel <riel@...hat.com>,
        Laura Abbott <labbott@...hat.com>, Greg KH <greg@...ah.com>,
        Andy Lutomirski <luto@...nel.org>, linux-mm@...ck.org,
        linux-arch@...r.kernel.org, linux-kernel@...r.kernel.org,
        kernel-hardening@...ts.openwall.com
Subject: Re: [RESEND][PATCH 0/3] exec: Pin stack limit during exec

On Wed 14-02-18 12:06:33, Kees Cook 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.
> 
> Neither I nor 0-day have found issues with this series, so I'd like to
> get it into -mm for further testing.

Sorry, for the late response. All three patches make sense to me.
finalize_exec could see a much better documentation and explain what is
the semantic.

Anyway, feel free to add
Acked-by: Michal Hocko <mhocko@...e.com>
-- 
Michal Hocko
SUSE Labs