[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <CAJcbSZG21d3=1w5eiWtxUF4ooDiGPZc7wOExPsGiB3D3wTUFLQ@mail.gmail.com>
Date: Wed, 8 Mar 2017 14:27:18 -0800
From: Thomas Garnier <thgarnie@...gle.com>
To: Andy Lutomirski <luto@...capital.net>
Cc: Russell King - ARM Linux <linux@...linux.org.uk>, Arnd Bergmann <arnd@...db.de>,
David Howells <dhowells@...hat.com>, Al Viro <viro@...iv.linux.org.uk>,
Dave Hansen <dave.hansen@...el.com>, René Nyffenegger <mail@...enyffenegger.ch>,
Andrew Morton <akpm@...ux-foundation.org>, Kees Cook <keescook@...omium.org>,
"Paul E . McKenney" <paulmck@...ux.vnet.ibm.com>, Petr Mladek <pmladek@...e.com>,
Andy Lutomirski <luto@...nel.org>, Ard Biesheuvel <ard.biesheuvel@...aro.org>,
Nicolas Pitre <nicolas.pitre@...aro.org>,
Sebastian Andrzej Siewior <bigeasy@...utronix.de>, Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
Helge Deller <deller@....de>, Rik van Riel <riel@...hat.com>, Ingo Molnar <mingo@...nel.org>,
John Stultz <john.stultz@...aro.org>, Thomas Gleixner <tglx@...utronix.de>,
Oleg Nesterov <oleg@...hat.com>, Stanislav Kinsburskiy <skinsbursky@...tuozzo.com>,
Pavel Tikhomirov <ptikhomirov@...tuozzo.com>, Stephen Smalley <sds@...ho.nsa.gov>,
Frederic Weisbecker <fweisbec@...il.com>, Ingo Molnar <mingo@...hat.com>, "H . Peter Anvin" <hpa@...or.com>,
Paolo Bonzini <pbonzini@...hat.com>, Dmitry Safonov <dsafonov@...tuozzo.com>,
Borislav Petkov <bp@...en8.de>, Josh Poimboeuf <jpoimboe@...hat.com>, Brian Gerst <brgerst@...il.com>,
Alexander Potapenko <glider@...gle.com>, Jan Beulich <JBeulich@...e.com>, Will Deacon <will.deacon@....com>,
Catalin Marinas <catalin.marinas@....com>, Mark Rutland <mark.rutland@....com>,
James Morse <james.morse@....com>, Chris Metcalf <cmetcalf@...lanox.com>,
Laura Abbott <labbott@...hat.com>, Andre Przywara <andre.przywara@....com>,
Linux API <linux-api@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, X86 ML <x86@...nel.org>,
"linux-arm-kernel@...ts.infradead.org" <linux-arm-kernel@...ts.infradead.org>,
"kernel-hardening@...ts.openwall.com" <kernel-hardening@...ts.openwall.com>
Subject: Re: [PATCH v1 1/4] syscalls: Restore address limit after a syscall
That make sense. I will optimize each architecture to not require a call.
On Wed, Mar 8, 2017 at 2:20 PM, Andy Lutomirski <luto@...capital.net> wrote:
> On Wed, Mar 8, 2017 at 1:58 PM, Russell King - ARM Linux
> <linux@...linux.org.uk> wrote:
>> On Wed, Mar 08, 2017 at 01:38:41PM -0800, Thomas Garnier wrote:
>>> This patch prevents a syscall to modify the address limit of the
>>> caller. The address limit is kept by the syscall wrapper and restored
>>> just after the syscall ends.
>>
>> I would much rather architectures were given the opportunity to code up
>> checks like this efficiently (iow, inline in the exit path assembly),
>> rather than having to unconditionally call an additional function on
>> every syscall, with its register saving overheads.
>>
>
> Me too. I think the two config choices should be:
>
> (a) BUG_ON(!segment_eq(...));
>
> (b) No generic check at all -- arch code will handle it
>
> --Andy
--
Thomas
Powered by blists - more mailing lists
Confused about mailing lists and their use?
Read about mailing lists on Wikipedia
and check out these
guidelines on proper formatting of your messages.
