From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 30 Mar 2017 20:45:28 +0100 From: Russell King - ARM Linux Message-ID: <20170330194528.GJ7909@n2100.armlinux.org.uk> References: <1490884982-5066-1-git-send-email-hoeun.ryu@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: Russell King - ARM Linux Subject: [kernel-hardening] Re: [RFCv2] arm64: support HAVE_ARCH_RARE_WRITE and HAVE_ARCH_RARE_WRITE_MEMCPY To: Kees Cook Cc: Hoeun Ryu , "kernel-hardening@lists.openwall.com" , Andy Lutomirski , PaX Team , Emese Revfy , "x86@kernel.org" , Catalin Marinas , Will Deacon , Ard Biesheuvel , Christoffer Dall , Mark Rutland , Suzuki K Poulose , Laura Abbott , Hugh Dickins , Steve Capper , Ganapatrao Kulkarni , James Morse , Kefeng Wang , "linux-arm-kernel@lists.infradead.org" , LKML List-ID: On Thu, Mar 30, 2017 at 12:38:15PM -0700, Kees Cook wrote: > Great work! I think this will need some further changes, though, since > it doesn't look to me like this would pass LKDTM's tests if it was > built as a module. (This is missing from my ARM attempt too... I > haven't figured out how to set the domain on the kernel modules...) You're not going to be able to do it very easily. The only way I can think of achieving it would be to split the module area into one chunk for text, one chunk for write-rare and one chunk for data. I still think that using domains is a mistake for this - it's a good solution for things that are contiguous and big (like userspace), but not for small amounts of data (like module sections.) -- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up according to speedtest.net.