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Message-ID: <CABqD9hZ25W58Yj6byoWTi+DdDGs6jvhtGpkRXiHPSGppbkTnhQ@mail.gmail.com>
Date: Wed, 18 Jan 2012 13:58:26 -0600
From: Will Drewry <wad@...omium.org>
To: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Andi Kleen <andi@...stfloor.org>, Indan Zupancic <indan@....nu>,
Jamie Lokier <jamie@...reable.org>,
Andrew Lutomirski <luto@....edu>,
Oleg Nesterov <oleg@...hat.com>, linux-kernel@...r.kernel.org,
keescook@...omium.org, john.johansen@...onical.com,
serge.hallyn@...onical.com, coreyb@...ux.vnet.ibm.com,
pmoore@...hat.com, eparis@...hat.com, djm@...drot.org,
segoon@...nwall.com, rostedt@...dmis.org, jmorris@...ei.org,
scarybeasts@...il.com, avi@...hat.com, penberg@...helsinki.fi,
viro@...iv.linux.org.uk, mingo@...e.hu, akpm@...ux-foundation.org,
khilman@...com, borislav.petkov@....com, amwang@...hat.com,
ak@...ux.intel.com, eric.dumazet@...il.com, gregkh@...e.de,
dhowells@...hat.com, daniel.lezcano@...e.fr,
linux-fsdevel@...r.kernel.org,
linux-security-module@...r.kernel.org, olofj@...omium.org,
mhalcrow@...gle.com, dlaor@...hat.com,
Roland McGrath <mcgrathr@...omium.org>
Subject: Re: Compat 32-bit syscall entry from 64-bit task!?
On Wed, Jan 18, 2012 at 1:52 PM, Will Drewry <wad@...omium.org> wrote:
> On Wed, Jan 18, 2012 at 1:47 PM, Linus Torvalds
> <torvalds@...ux-foundation.org> wrote:
>> On Wed, Jan 18, 2012 at 11:44 AM, Andi Kleen <andi@...stfloor.org> wrote:
>>>
>>> It can securely enable syscall auditing which can catch all syscalls
>>> (however you only get race free memory arguments for the ones with LSM hooks
>>> at the right place). Really need both.
>>>
>>> I agree it's not easy to get tight (and also not pretty), but you have a lot
>>> better chance doing it this way than with ptrace.
>>
>> .. And how the f*^& did you imagine that something like chrome would do that?
>>
>> You need massive amounts of privileges, and it's a total disaster in
>> every single respect.
>>
>> Stop pushing crap. No, ptrace isn't wonderful, but your LSM+auditing
>> idea is a billion times worse in all respects.
>>
>> We can definitely fix the ptrace issue with compat system calls.
>
> FWIW, it looks like audit needs fixing too. If a process only uses
> TIF_SYSCALL_AUDIT, then the fast-path will properly annotate the entry
> with AUDIT_ARCH_I386, but if it takes the slow path because of some
> other tracing on a thread (ftrace, ptrace, ...), then the audit record
> will incorrectly use TIF_IA32 to write the audit record. Easy patch
> (I'll write it up shortly), but yet another case of breakage.
Nevermind - mis-derefenced the IS_IA32 define.
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