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From: Andy Isaacson <adi@hexapodia.org>
To: Davide Libenzi <davidel@xmailserver.org>
Cc: Kyle Moffett <mrmacman_g4@mac.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Rik van Riel <riel@redhat.com>
Subject: Re: [patch 0/4] MAP_NOZERO v2 - VM_NOZERO/MAP_NOZERO early summer madness
Date: Mon, 2 Jul 2007 11:38:35 -0700	[thread overview]
Message-ID: <20070702183835.GM9157@hexapodia.org> (raw)
In-Reply-To: <Pine.LNX.4.64.0706291711320.31176@alien.or.mcafeemobile.com>

On Sat, Jun 30, 2007 at 12:03:07PM -0700, Davide Libenzi wrote:
> I think the focus should be to find a case where under the currently 
> implemented policy for MAP_NOZERO, MAP_NOZERO represent a loss of security 
> WRT no MAP_NOZERO.   I have not been able to find one yet, although Andy 
> found a potential one in the setuid+exec/ptrace race (fixed by a patch 
> that should IMO go in in any case).

BTW, the ptrace variant of this issue is not a problem -- PTRACE_ATTACH
running as newuid gets EPERM when trying to attach at /* here */ below.

    setuid(newuid);
    /* here */
    exec(...);
    exit(1);

sys_setuid sets current->mm->dumpable = suid_dumpable, so unless the
admin asked for it, there is no risk WRT PTRACE_ATTACH.  However, this
risk vector does need to be considered when implementing MAP_NOZERO.

-andy

  parent reply	other threads:[~2007-07-02 18:38 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-06-28 18:49 [patch 0/4] MAP_NOZERO v2 - VM_NOZERO/MAP_NOZERO early summer madness Davide Libenzi
2007-06-29  2:57 ` Kyle Moffett
2007-06-29  3:04   ` Rik van Riel
2007-06-29  5:09     ` Ulrich Drepper
2007-06-29  5:20   ` Davide Libenzi
2007-06-29 19:39   ` Andy Isaacson
2007-06-29 20:12     ` Davide Libenzi
2007-06-29 23:48       ` Kyle Moffett
2007-06-30 19:03         ` Davide Libenzi
2007-06-30 23:46           ` Kyle Moffett
2007-06-30 23:57             ` Davide Libenzi
2007-07-01  0:21               ` Kyle Moffett
2007-07-01  4:25                 ` Davide Libenzi
2007-07-02 19:00                 ` Andy Isaacson
2007-07-02 19:03                   ` Rik van Riel
2007-07-02 19:06                     ` Ulrich Drepper
2007-07-02 22:46                       ` Davide Libenzi
2007-07-02 22:55                         ` Rik van Riel
2007-07-02 23:46                           ` Davide Libenzi
2007-07-04 21:53                           ` Andy Isaacson
2007-07-04 23:42                             ` Davide Libenzi
2007-07-02 18:38           ` Andy Isaacson [this message]
2007-07-02 22:38             ` Davide Libenzi

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