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From: Oleg Nesterov <oleg@redhat.com>
To: Kees Cook <keescook@chromium.org>
Cc: Rik van Riel <riel@redhat.com>, Michal Hocko <mhocko@suse.com>,
	Stanislav Kozina <skozina@redhat.com>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: get_arg_page() && ptr_size accounting
Date: Tue, 11 Sep 2018 17:25:31 +0200	[thread overview]
Message-ID: <20180911152531.GA9450@redhat.com> (raw)
In-Reply-To: <CAGXu5jL_a5B6w39Vb3S07-Epu4JGPTB5N6A75ERVOryvNeA7ZA@mail.gmail.com>

On 09/10, Kees Cook wrote:
>
> On Mon, Sep 10, 2018 at 10:21 AM, Oleg Nesterov <oleg@redhat.com> wrote:
>
> > Could you explain what this patch actually prevents from? Especially
> > now that we have stack_guard_gap?
>
> One of the many Stack Clash abuses was that it was possible to jump
> over the stack gap with outrageous environment variables that got
> expanded in stupid ways by, IIRC, glibc or the dynamic linker. The
> point here was to be defensive in the face of future weaknesses, and
> try to be robust in the face of crazy execs but workable under normal
> (but large) execs.

IOW, unlimited arg size makes many interesting attacks possible.

This is clear, I was confused because I thought this patch fixes some
particular problem not explained in the changelog.

Thanks,

Oleg.


  reply	other threads:[~2018-09-11 15:25 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-10 12:29 get_arg_page() && ptr_size accounting Oleg Nesterov
2018-09-10 16:41 ` Kees Cook
2018-09-10 16:45   ` Kees Cook
2018-09-10 17:21     ` Oleg Nesterov
2018-09-10 17:43       ` Oleg Nesterov
2018-09-11  4:30         ` Kees Cook
2018-09-11 15:29           ` Oleg Nesterov
2018-09-11  4:27       ` Kees Cook
2018-09-11 15:25         ` Oleg Nesterov [this message]
2018-09-10 17:18   ` Oleg Nesterov
2018-09-11  4:23     ` Kees Cook
2018-09-11 14:13       ` Oleg Nesterov
2018-09-11 19:06         ` Kees Cook
2018-09-12 12:27           ` Oleg Nesterov
2018-09-12 14:23             ` Oleg Nesterov
2018-09-12 20:42             ` Kees Cook

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