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From: Rik van Riel <riel@redhat.com>
To: Michal Hocko <mhocko@kernel.org>, Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	Andy Lutomirski <luto@kernel.org>,
	Ben Hutchings <ben@decadent.org.uk>, Willy Tarreau <w@1wt.eu>,
	Hugh Dickins <hughd@google.com>, Oleg Nesterov <oleg@redhat.com>,
	"Jason A. Donenfeld" <Jason@zx2c4.com>,
	Larry Woodman <lwoodman@redhat.com>,
	"Kirill A. Shutemov" <kirill@shutemov.name>,
	Tony Luck <tony.luck@intel.com>,
	"James E.J. Bottomley" <jejb@parisc-linux.org>,
	Helge Diller <deller@gmx.de>,
	James Hogan <james.hogan@imgtec.com>,
	Laura Abbott <labbott@redhat.com>, Greg KH <greg@kroah.com>,
	"security@kernel.org" <security@kernel.org>,
	Qualys Security Advisory <qsa@qualys.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Ximin Luo <infinity0@debian.org>
Subject: Re: [RFC][PATCH] exec: Use init rlimits for setuid exec
Date: Mon, 10 Jul 2017 14:29:45 -0400	[thread overview]
Message-ID: <1499711385.6130.41.camel@redhat.com> (raw)
In-Reply-To: <20170710181600.GG7071@dhcp22.suse.cz>

On Mon, 2017-07-10 at 20:16 +0200, Michal Hocko wrote:

> OK, I misread the code. 32b applications on 64b systems do top down
> by
> default and only if they override this by ADDR_COMPAT_LAYOUT
> personality. For some reason I thought that 32b userspace goes a
> different path and makes sure that they are always doing bottom up.
> 
> Anyway even if somebody really needs to grow stack really large we
> have
> the personality to give them the legacy layout.

I think what will happen when rlimit_stack is RLIMIT_INFINITY
is that mmap_base will end up placing mm->mmap_base at 512MB
(task_size / 6 * 5 below the top of address space) for 32 bit
kernels, and we eventually fall back to a bottom-up search
if the space below mmap_base is exhausted (if it ever is).

  reply	other threads:[~2017-07-10 18:29 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-07-06  4:32 [RFC][PATCH] exec: Use init rlimits for setuid exec Kees Cook
2017-07-06  4:59 ` Andy Lutomirski
2017-07-06 12:45   ` Eric W. Biederman
2017-07-06 15:27     ` Andy Lutomirski
2017-07-06  5:47 ` Willy Tarreau
2017-07-06 12:38 ` Eric W. Biederman
2017-07-06 15:30   ` Andy Lutomirski
2017-07-06 16:34 ` Linus Torvalds
2017-07-06 16:50   ` Linus Torvalds
2017-07-06 17:29   ` Kees Cook
2017-07-06 17:52     ` Linus Torvalds
2017-07-06 19:12       ` Kees Cook
2017-07-07  4:48         ` Andy Lutomirski
2017-07-07  5:03           ` Linus Torvalds
2017-07-07  5:10           ` Kees Cook
2017-07-07  5:15             ` Kees Cook
2017-07-07  5:36               ` Andy Lutomirski
2017-07-07  5:45                 ` Kees Cook
2017-07-07  6:02                   ` Linus Torvalds
2017-07-07  6:10                     ` Kees Cook
2017-07-07 16:06                       ` Linus Torvalds
2017-07-07 18:28                         ` Kees Cook
2017-07-07 14:48                   ` Andy Lutomirski
2017-07-07  5:39               ` Linus Torvalds
2017-07-07  5:49                 ` Kees Cook
2017-07-07  6:40                   ` Kees Cook
2017-07-07 16:22                     ` Linus Torvalds
2017-07-07 18:27                       ` Kees Cook
2017-07-10  8:44         ` Michal Hocko
2017-07-10 16:12           ` Kees Cook
2017-07-10 16:18             ` Linus Torvalds
2017-07-10 16:52               ` Willy Tarreau
2017-07-10 16:27             ` Michal Hocko
2017-07-10 18:16               ` Michal Hocko
2017-07-10 18:29                 ` Rik van Riel [this message]
2017-07-12 23:50   ` Alan Cox

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