From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753144AbdC2SYB (ORCPT ); Wed, 29 Mar 2017 14:24:01 -0400 Received: from mail-it0-f51.google.com ([209.85.214.51]:36007 "EHLO mail-it0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752264AbdC2SX7 (ORCPT ); Wed, 29 Mar 2017 14:23:59 -0400 MIME-Version: 1.0 In-Reply-To: <1490811363-93944-2-git-send-email-keescook@chromium.org> References: <1490811363-93944-1-git-send-email-keescook@chromium.org> <1490811363-93944-2-git-send-email-keescook@chromium.org> From: Kees Cook Date: Wed, 29 Mar 2017 11:23:57 -0700 X-Google-Sender-Auth: bg9kc_I2sI65KcEHan0KrNzTbJI Message-ID: Subject: Re: [RFC v2][PATCH 01/11] Introduce rare_write() infrastructure To: "kernel-hardening@lists.openwall.com" Cc: Kees Cook , Mark Rutland , Andy Lutomirski , Hoeun Ryu , PaX Team , Emese Revfy , Russell King , "x86@kernel.org" , LKML , "linux-arm-kernel@lists.infradead.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Mar 29, 2017 at 11:15 AM, Kees Cook wrote: > +/* > + * Build "write rarely" infrastructure for flipping memory r/w > + * on a per-CPU basis. > + */ > +#ifndef CONFIG_HAVE_ARCH_RARE_WRITE > +# define __wr_rare > +# define __wr_rare_type > +# define __rare_write(__var, __val) (__var = (__val)) > +# define rare_write_begin() do { } while (0) > +# define rare_write_end() do { } while (0) > +#else > +# define __wr_rare __ro_after_init > +# define __wr_rare_type const > +# ifdef CONFIG_HAVE_ARCH_RARE_WRITE_MEMCPY > +# define __rare_write_n(dst, src, len) ({ \ > + BUILD_BUG(!builtin_const(len)); \ > + __arch_rare_write_memcpy((dst), (src), (len)); \ > + }) > +# define __rare_write(var, val) __rare_write_n(&(var), &(val), sizeof(var)) > +# else > +# define __rare_write(var, val) ((*(typeof((typeof(var))0) *)&(var)) = (val)) > +# endif > +# define rare_write_begin() __arch_rare_write_begin() > +# define rare_write_end() __arch_rare_write_end() > +#endif > +#define rare_write(__var, __val) ({ \ > + rare_write_begin(); \ > + __rare_write(__var, __val); \ > + rare_write_end(); \ > + __var; \ > +}) > + Of course, only after sending this do I realize that the MEMCPY case will need to be further adjusted, since it currently can't take literals. I guess something like this needs to be done: #define __rare_write(var, val) ({ \ typeof(var) __src = (val); \ __rare_write_n(&(var), &(__src), sizeof(var)); \ }) -Kees -- Kees Cook Pixel Security From mboxrd@z Thu Jan 1 00:00:00 1970 From: keescook@chromium.org (Kees Cook) Date: Wed, 29 Mar 2017 11:23:57 -0700 Subject: [RFC v2][PATCH 01/11] Introduce rare_write() infrastructure In-Reply-To: <1490811363-93944-2-git-send-email-keescook@chromium.org> References: <1490811363-93944-1-git-send-email-keescook@chromium.org> <1490811363-93944-2-git-send-email-keescook@chromium.org> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Wed, Mar 29, 2017 at 11:15 AM, Kees Cook wrote: > +/* > + * Build "write rarely" infrastructure for flipping memory r/w > + * on a per-CPU basis. > + */ > +#ifndef CONFIG_HAVE_ARCH_RARE_WRITE > +# define __wr_rare > +# define __wr_rare_type > +# define __rare_write(__var, __val) (__var = (__val)) > +# define rare_write_begin() do { } while (0) > +# define rare_write_end() do { } while (0) > +#else > +# define __wr_rare __ro_after_init > +# define __wr_rare_type const > +# ifdef CONFIG_HAVE_ARCH_RARE_WRITE_MEMCPY > +# define __rare_write_n(dst, src, len) ({ \ > + BUILD_BUG(!builtin_const(len)); \ > + __arch_rare_write_memcpy((dst), (src), (len)); \ > + }) > +# define __rare_write(var, val) __rare_write_n(&(var), &(val), sizeof(var)) > +# else > +# define __rare_write(var, val) ((*(typeof((typeof(var))0) *)&(var)) = (val)) > +# endif > +# define rare_write_begin() __arch_rare_write_begin() > +# define rare_write_end() __arch_rare_write_end() > +#endif > +#define rare_write(__var, __val) ({ \ > + rare_write_begin(); \ > + __rare_write(__var, __val); \ > + rare_write_end(); \ > + __var; \ > +}) > + Of course, only after sending this do I realize that the MEMCPY case will need to be further adjusted, since it currently can't take literals. I guess something like this needs to be done: #define __rare_write(var, val) ({ \ typeof(var) __src = (val); \ __rare_write_n(&(var), &(__src), sizeof(var)); \ }) -Kees -- Kees Cook Pixel Security From mboxrd@z Thu Jan 1 00:00:00 1970 MIME-Version: 1.0 Sender: keescook@google.com In-Reply-To: <1490811363-93944-2-git-send-email-keescook@chromium.org> References: <1490811363-93944-1-git-send-email-keescook@chromium.org> <1490811363-93944-2-git-send-email-keescook@chromium.org> From: Kees Cook Date: Wed, 29 Mar 2017 11:23:57 -0700 Message-ID: Content-Type: text/plain; charset=UTF-8 Subject: [kernel-hardening] Re: [RFC v2][PATCH 01/11] Introduce rare_write() infrastructure To: "kernel-hardening@lists.openwall.com" Cc: Kees Cook , Mark Rutland , Andy Lutomirski , Hoeun Ryu , PaX Team , Emese Revfy , Russell King , "x86@kernel.org" , LKML , "linux-arm-kernel@lists.infradead.org" List-ID: On Wed, Mar 29, 2017 at 11:15 AM, Kees Cook wrote: > +/* > + * Build "write rarely" infrastructure for flipping memory r/w > + * on a per-CPU basis. > + */ > +#ifndef CONFIG_HAVE_ARCH_RARE_WRITE > +# define __wr_rare > +# define __wr_rare_type > +# define __rare_write(__var, __val) (__var = (__val)) > +# define rare_write_begin() do { } while (0) > +# define rare_write_end() do { } while (0) > +#else > +# define __wr_rare __ro_after_init > +# define __wr_rare_type const > +# ifdef CONFIG_HAVE_ARCH_RARE_WRITE_MEMCPY > +# define __rare_write_n(dst, src, len) ({ \ > + BUILD_BUG(!builtin_const(len)); \ > + __arch_rare_write_memcpy((dst), (src), (len)); \ > + }) > +# define __rare_write(var, val) __rare_write_n(&(var), &(val), sizeof(var)) > +# else > +# define __rare_write(var, val) ((*(typeof((typeof(var))0) *)&(var)) = (val)) > +# endif > +# define rare_write_begin() __arch_rare_write_begin() > +# define rare_write_end() __arch_rare_write_end() > +#endif > +#define rare_write(__var, __val) ({ \ > + rare_write_begin(); \ > + __rare_write(__var, __val); \ > + rare_write_end(); \ > + __var; \ > +}) > + Of course, only after sending this do I realize that the MEMCPY case will need to be further adjusted, since it currently can't take literals. I guess something like this needs to be done: #define __rare_write(var, val) ({ \ typeof(var) __src = (val); \ __rare_write_n(&(var), &(__src), sizeof(var)); \ }) -Kees -- Kees Cook Pixel Security