From: Mark Rutland <mark.rutland@arm.com>
To: Kees Cook <keescook@chromium.org>
Cc: "kernel-hardening@lists.openwall.com"
<kernel-hardening@lists.openwall.com>
Subject: Re: [kernel-hardening] patches for __write_rarely section
Date: Fri, 18 Nov 2016 11:42:35 +0000 [thread overview]
Message-ID: <20161118114234.GB1197@leverpostej> (raw)
In-Reply-To: <20161118111059.GA1197@leverpostej>
On Fri, Nov 18, 2016 at 11:10:59AM +0000, Mark Rutland wrote:
> With something like the below (assuming all helpers are inlined):
>
> #define rare_write(__var, __val) ({ \
> typeof(var) *__rw_var; \
... iwith s/var/__var/ here...
> __some_typecheck_perhaps(__var, __val); \
> \
> __rw_var = __rare_rw_ptr(&(__var)); \
> \
> __rare_rw_map(); \
> *__rw_var = (__val); \
> __rare_rw_unmap(); \
> \
> __clobber_var_so_gcc_knows(__var); \
> })
... and with explicit clobber gone, since __rare_rw_unmap would
presumably have to have a memory clobber anyway, just like the fixmap
code.
Thanks,
Mark.
next prev parent reply other threads:[~2016-11-18 11:42 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-16 14:39 [kernel-hardening] patches for __write_rarely section Gengjia Chen
2016-11-16 15:16 ` Mark Rutland
2016-11-17 23:47 ` Kees Cook
2016-11-18 11:10 ` Mark Rutland
2016-11-18 11:42 ` Mark Rutland [this message]
2016-11-16 15:22 ` Rik van Riel
2016-11-16 16:14 ` Greg KH
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