From: Mark Rutland <mark.rutland@arm.com>
To: Andy Lutomirski <luto@kernel.org>
Cc: Mathias Krause <minipli@googlemail.com>,
Thomas Gleixner <tglx@linutronix.de>,
Kees Cook <keescook@chromium.org>,
"kernel-hardening@lists.openwall.com"
<kernel-hardening@lists.openwall.com>,
Hoeun Ryu <hoeun.ryu@gmail.com>, PaX Team <pageexec@freemail.hu>,
Emese Revfy <re.emese@gmail.com>,
Russell King <linux@armlinux.org.uk>, X86 ML <x86@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
Peter Zijlstra <peterz@infradead.org>
Subject: Re: [kernel-hardening] Re: [RFC v2][PATCH 04/11] x86: Implement __arch_rare_write_begin/unmap()
Date: Fri, 7 Apr 2017 17:22:39 +0100 [thread overview]
Message-ID: <20170407162238.GD858@leverpostej> (raw)
In-Reply-To: <CALCETrWuZPDjAuE1jnhJNKiZOOEdbus-O6GY8++0UO56Q84PZw@mail.gmail.com>
On Fri, Apr 07, 2017 at 09:14:29AM -0700, Andy Lutomirski wrote:
> I think we're approaching this all wrong, actually. The fact that x86
> has this CR0.WP thing is arguably a historical accident, and the fact
> that PaX uses it doesn't mean that PaX is doing it the best way for
> upstream Linux.
>
> Why don't we start at the other end and do a generic non-arch-specific
> implementation: set up an mm_struct that contains an RW alias of the
> relevant parts of rodata and use use_mm to access it. (That is,
> get_fs() to back up the old fs, set_fs(USER_DS),
> use_mm(&rare_write_mm), do the write using copy_to_user, undo
> everything.)
FWIW, I completely agree with this approach.
That's largely the approach arm64 would have to take regardless (as per
Hoeun's patches), and having a consistent common implementation would be
desireable.
There are a couple of other complications to handle (e.g. a perf
interrupt coming in and trying to read from the mapping), but I think we
can handle that generically.
Thanks,
Mark.
next prev parent reply other threads:[~2017-04-07 16:23 UTC|newest]
Thread overview: 63+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-29 18:15 [RFC v2] Introduce rare_write() infrastructure Kees Cook
2017-03-29 18:15 ` [RFC v2][PATCH 01/11] " Kees Cook
2017-03-29 18:23 ` Kees Cook
2017-03-30 7:44 ` Ho-Eun Ryu
2017-03-30 17:02 ` Kees Cook
2017-04-07 8:09 ` Ho-Eun Ryu
2017-04-07 20:38 ` Kees Cook
2017-03-29 18:15 ` [RFC v2][PATCH 02/11] lkdtm: add test for " Kees Cook
2017-03-30 9:34 ` [kernel-hardening] " Ian Campbell
2017-03-30 16:16 ` Kees Cook
2017-03-29 18:15 ` [RFC v2][PATCH 03/11] net: switch sock_diag handlers to rare_write() Kees Cook
2017-03-29 18:15 ` [RFC v2][PATCH 04/11] x86: Implement __arch_rare_write_begin/unmap() Kees Cook
2017-03-29 22:38 ` Andy Lutomirski
2017-03-30 1:41 ` Kees Cook
2017-04-05 23:57 ` Andy Lutomirski
2017-04-06 0:14 ` Kees Cook
2017-04-06 15:59 ` Andy Lutomirski
2017-04-07 8:34 ` [kernel-hardening] " Mathias Krause
2017-04-07 9:46 ` Thomas Gleixner
2017-04-07 10:51 ` Mathias Krause
2017-04-07 13:14 ` Thomas Gleixner
2017-04-07 13:30 ` Mathias Krause
2017-04-07 16:14 ` Andy Lutomirski
2017-04-07 16:22 ` Mark Rutland [this message]
2017-04-07 19:58 ` PaX Team
2017-04-08 4:58 ` Andy Lutomirski
2017-04-09 12:47 ` PaX Team
2017-04-10 0:10 ` Andy Lutomirski
2017-04-10 10:42 ` PaX Team
2017-04-10 16:01 ` Andy Lutomirski
2017-04-07 20:44 ` Thomas Gleixner
2017-04-07 21:20 ` Kees Cook
2017-04-08 4:12 ` Daniel Micay
2017-04-08 4:13 ` Daniel Micay
2017-04-08 4:21 ` Daniel Micay
2017-04-08 5:07 ` Andy Lutomirski
2017-04-08 7:33 ` Daniel Micay
2017-04-08 15:20 ` Andy Lutomirski
2017-04-09 10:53 ` Ingo Molnar
2017-04-10 10:22 ` Mark Rutland
2017-04-09 20:24 ` PaX Team
2017-04-10 0:31 ` Andy Lutomirski
2017-04-10 19:47 ` PaX Team
2017-04-10 20:27 ` Andy Lutomirski
2017-04-10 20:13 ` Kees Cook
2017-04-10 20:17 ` Andy Lutomirski
2017-04-07 19:25 ` Thomas Gleixner
2017-04-07 14:45 ` Peter Zijlstra
2017-04-10 10:29 ` Mark Rutland
2017-04-07 19:52 ` PaX Team
2017-04-10 8:26 ` Thomas Gleixner
2017-04-10 19:55 ` PaX Team
2017-04-07 9:37 ` Peter Zijlstra
2017-03-29 18:15 ` [RFC v2][PATCH 05/11] ARM: mm: dump: Add domain to output Kees Cook
2017-03-29 18:15 ` [RFC v2][PATCH 06/11] ARM: domains: Extract common USER domain init Kees Cook
2017-03-29 18:15 ` [RFC v2][PATCH 07/11] ARM: mm: set DOMAIN_WR_RARE for rodata Kees Cook
2017-03-29 18:16 ` [RFC v2][PATCH 08/11] ARM: Implement __arch_rare_write_begin/end() Kees Cook
2017-04-07 9:36 ` Peter Zijlstra
2017-03-29 18:16 ` [RFC v2][PATCH 09/11] list: add rare_write() list helpers Kees Cook
2017-03-29 18:16 ` [RFC v2][PATCH 10/11] gcc-plugins: Add constify plugin Kees Cook
2017-03-29 18:16 ` [RFC v2][PATCH 11/11] cgroups: force all struct cftype const Kees Cook
2017-03-29 19:00 ` [RFC v2] Introduce rare_write() infrastructure Russell King - ARM Linux
2017-03-29 19:14 ` Kees Cook
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