linux-kernel - Re: [patch] honour MNT

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <9a8748490610080339t668095b9v15c4d0040dabae89@mail.gmail.com>
Date:	Sun, 8 Oct 2006 12:39:42 +0200
From:	"Jesper Juhl" <jesper.juhl@...il.com>
To:	"Jeremy Fitzhardinge" <jeremy@...p.org>
Cc:	"Stas Sergeev" <stsp@...et.ru>,
	"Alan Cox" <alan@...rguk.ukuu.org.uk>,
	"Jakub Jelinek" <jakub@...hat.com>,
	"Arjan van de Ven" <arjan@...radead.org>,
	"Linux kernel" <linux-kernel@...r.kernel.org>,
	"Hugh Dickins" <hugh@...itas.com>,
	"Ulrich Drepper" <drepper@...hat.com>
Subject: Re: [patch] honour MNT_NOEXEC for access()

On 08/10/06, Jeremy Fitzhardinge <jeremy@...p.org> wrote:
[snip]
> Also, I guess there's the general question of what the noexec mount flag
> really means?  Does it mean "make the execve syscall fail", or does it
> mean "no bits on this filesystem may be interpreted as instructions".
> The former is simple to implement, but probably not very useful; the
> latter is not possible to implement in general.
>

As I see it, what we can resonably do with 'noexec' is
- make execve() fail.
- make access(), faccessat() return EACCESS for files stored on
'noexec' filesystems.
- make mmap(...PROT_EXEC...) fail for files stored on 'noexec' filesystems.

For things like /dev/shm we can additionally let 'noexec' mean "don't
allow executable shared memory".

Since we can't really prevent things like perl/php/bash/tcl/whatever
scripts from being executed/interpreted from there with this
mechanism, let's not worry about that.  Leave that for things like
SELinux to deal with.

I don't think we can do much more with 'noexec'.


-- 
Jesper Juhl <jesper.juhl@...il.com>
Don't top-post  http://www.catb.org/~esr/jargon/html/T/top-post.html
Plain text mails only, please      http://www.expita.com/nomime.html
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/