From: Thomas Gleixner <tglx@linutronix.de>
To: Andi Kleen <andi@firstfloor.org>
Cc: Andy Lutomirski <luto@MIT.EDU>, Ingo Molnar <mingo@elte.hu>,
x86@kernel.org, linux-kernel@vger.kernel.org,
Jesper Juhl <jj@chaosbits.net>, Borislav Petkov <bp@alien8.de>,
Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
Arjan van de Ven <arjan@infradead.org>,
Jan Beulich <JBeulich@novell.com>,
richard -rw- weinberger <richard.weinberger@gmail.com>,
Mikael Pettersson <mikpe@it.uu.se>
Subject: Re: [PATCH v4 10/10] x86-64: Add CONFIG_UNSAFE_VSYSCALLS to feature-removal-schedule
Date: Tue, 31 May 2011 20:57:27 +0200 (CEST) [thread overview]
Message-ID: <alpine.LFD.2.02.1105312056120.3078@ionos> (raw)
In-Reply-To: <20110531183448.GA27166@one.firstfloor.org>
On Tue, 31 May 2011, Andi Kleen wrote:
> > +What: CONFIG_UNSAFE_VSYSCALLS (x86_64)
> > +When: When glibc 2.14 or newer is ubitquitous. Perhaps mid-2012.
> > +Why: Having user-executable code at a fixed address is a security problem.
> > + Turning off CONFIG_UNSAFE_VSYSCALLS mostly removes the risk but will
> > + make the time() function slower on glibc versions 2.13 and below.
>
> I disagree with this description (and the whole idea really)
>
> First it's time+gettimeofday+vgetcu, not just time.
>
> A more accurate description is
>
> "will make all x86-64 Linux programs written to the original pre
> vDSO syscall ABI significantly slower"
>
> And the assumption that all world is using glibc is still as bad
> as it was on the first po.st
>
> And it's still a bad idea. Especially since there's a much better
> alternative anyways for the "security problem" which has none of
> these drawbacks.
How about posting an alternative patch?
Thanks,
tglx
next prev parent reply other threads:[~2011-05-31 18:57 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-31 14:13 [PATCH v4 00/10] Remove syscall instructions at fixed addresses Andy Lutomirski
2011-05-31 14:13 ` [PATCH v4 01/10] x86-64: Fix alignment of jiffies variable Andy Lutomirski
2011-05-31 14:14 ` [PATCH v4 02/10] x86-64: Document some of entry_64.S Andy Lutomirski
2011-05-31 14:14 ` [PATCH v4 03/10] x86-64: Give vvars their own page Andy Lutomirski
2011-05-31 17:17 ` Louis Rilling
2011-05-31 14:14 ` [PATCH v4 04/10] x86-64: Remove kernel.vsyscall64 sysctl Andy Lutomirski
2011-05-31 14:14 ` [PATCH v4 05/10] x86-64: Map the HPET NX Andy Lutomirski
2011-05-31 14:14 ` [PATCH v4 06/10] x86-64: Remove vsyscall number 3 (venosys) Andy Lutomirski
2011-05-31 14:14 ` [PATCH v4 07/10] x86-64: Fill unused parts of the vsyscall page with 0xcc Andy Lutomirski
2011-05-31 14:14 ` [PATCH v4 08/10] x86-64: Emulate legacy vsyscalls Andy Lutomirski
2011-05-31 15:35 ` Ingo Molnar
2011-05-31 14:14 ` [PATCH v4 09/10] x86-64: Randomize int 0xcc magic al values at boot Andy Lutomirski
2011-05-31 15:40 ` Ingo Molnar
2011-05-31 15:56 ` Andrew Lutomirski
2011-05-31 16:10 ` Andrew Lutomirski
2011-05-31 16:43 ` Ingo Molnar
2011-05-31 16:42 ` Ingo Molnar
2011-05-31 18:08 ` Andrew Lutomirski
2011-05-31 14:14 ` [PATCH v4 10/10] x86-64: Add CONFIG_UNSAFE_VSYSCALLS to feature-removal-schedule Andy Lutomirski
2011-05-31 18:34 ` Andi Kleen
2011-05-31 18:57 ` Thomas Gleixner [this message]
2011-05-31 18:59 ` Andrew Lutomirski
2011-05-31 19:28 ` Ingo Molnar
2011-05-31 19:36 ` Ingo Molnar
2011-05-31 20:05 ` Andrew Lutomirski
2011-05-31 20:24 ` Ingo Molnar
2011-08-06 20:18 ` [PATCH v3 " Andrew Lutomirski
2011-06-08 8:50 ` [PATCH v4 " Ingo Molnar
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