From: "H. Peter Anvin" <hpa@zytor.com>
To: Chuck Ebbert <76306.1226@compuserve.com>
Cc: linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [Announcement] "Exec Shield", new Linux security feature
Date: Sun, 04 May 2003 20:14:32 -0700 [thread overview]
Message-ID: <3EB5D718.4050101@zytor.com> (raw)
In-Reply-To: <200305041956_MC3-1-375E-31DB@compuserve.com>
Chuck Ebbert wrote:
>>There is another issue: x86 uses relative jumps, so although "ASCII
>>armor" addresses aren't easily accessible using return address smashes
>>(although the \0 at the end thing is a real issue), you may be able to
>>get to them through a jump instruction.
>
> Does the instruction-pointer-relative data addressing mode added by
> AMD64 make these exploits easier? Maybe someone should be working on a
> version of this patch for that platform...
>
No, they don't, not if your mode of exploit is hacking return addresses
on the stack.
AMD64 makes this pretty easy, *ALL* user-space addresses are in the
"ASCII armour" area, and it supports exec-off. Apparently this is
currently off by default, but Andi Kleen says that they have identified
the bug that caused it and they're making it available as a kernel option.
-hpa
next prev parent reply other threads:[~2003-05-05 3:02 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-05-04 23:55 [Announcement] "Exec Shield", new Linux security feature Chuck Ebbert
2003-05-05 3:14 ` H. Peter Anvin [this message]
-- strict thread matches above, loose matches on Subject: below --
2003-05-05 7:14 Ingo Molnar
2003-05-04 16:20 Yoav Weiss
[not found] <Pine.LNX.4.44.0305040404300.12757-100000@devserv.devel.redhat.com.suse.lists.linux.kernel>
[not found] ` <Pine.LNX.4.44.0305040448250.24497-100000@devserv.devel.redhat.com.suse.lists.linux.kernel>
2003-05-04 15:48 ` Andi Kleen
2003-05-04 14:25 Chuck Ebbert
2003-05-04 22:22 ` Richard Henderson
2003-05-05 0:41 ` H. Peter Anvin
2003-05-04 11:19 Yoav Weiss
2003-05-04 13:51 ` Ingo Molnar
2003-05-03 13:19 linux
2003-05-03 23:00 ` Valdis.Kletnieks
2003-05-04 7:03 ` Calin A. Culianu
2003-05-04 8:49 ` Arjan van de Ven
2003-05-05 13:35 ` Jesse Pollard
2003-05-04 15:24 ` linux
2003-05-02 22:46 Chuck Ebbert
[not found] <Pine.LNX.4.44.0305021325130.6565-100000@devserv.devel.redhat.com.suse.lists.linux.kernel>
[not found] ` <200305021829.h42ITclA000178@81-2-122-30.bradfords.org.uk.suse.lists.linux.kernel>
[not found] ` <b8udjm$cgq$1@cesium.transmeta.com.suse.lists.linux.kernel>
2003-05-02 20:51 ` Andi Kleen
2003-05-02 20:56 ` H. Peter Anvin
2003-05-02 21:07 ` Andi Kleen
2003-05-02 21:09 ` H. Peter Anvin
2003-05-02 21:25 ` Andi Kleen
2003-05-02 16:37 Ingo Molnar
2003-05-02 17:05 ` Matthias Andree
2003-05-02 17:12 ` Marc-Christian Petersen
2003-05-02 17:12 ` Davide Libenzi
2003-05-02 17:18 ` Arjan van de Ven
2003-05-02 17:32 ` Ingo Molnar
2003-05-02 18:29 ` John Bradford
2003-05-02 18:32 ` H. Peter Anvin
2003-05-02 19:09 ` David Mosberger
2003-05-02 18:51 ` Davide Libenzi
[not found] ` <20030502172011$0947@gated-at.bofh.it>
2003-05-02 18:17 ` Florian Weimer
2003-05-02 18:29 ` Davide Libenzi
2003-05-02 18:32 ` Florian Weimer
2003-05-02 18:50 ` Davide Libenzi
2003-05-02 21:48 ` Carl-Daniel Hailfinger
2003-05-03 6:52 ` Ingo Molnar
2003-05-03 9:56 ` Carl-Daniel Hailfinger
2003-05-03 12:48 ` Arjan van de Ven
2003-05-04 6:52 ` Calin A. Culianu
2003-05-04 8:10 ` Ingo Molnar
2003-05-04 8:52 ` Ingo Molnar
2003-05-04 15:40 ` Calin A. Culianu
2003-05-04 15:48 ` Sean Neakums
2003-05-04 15:23 ` Calin A. Culianu
2003-05-04 20:07 ` H. Peter Anvin
2003-05-04 20:57 ` Kasper Dupont
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