From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756456AbeDXIJr (ORCPT ); Tue, 24 Apr 2018 04:09:47 -0400 Received: from terminus.zytor.com ([198.137.202.136]:42795 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751161AbeDXIJk (ORCPT ); Tue, 24 Apr 2018 04:09:40 -0400 Date: Tue, 24 Apr 2018 01:08:37 -0700 From: tip-bot for Dave Hansen Message-ID: Cc: vbabka@suse.cz, torvalds@linux-foundation.org, jgross@suse.com, tglx@linutronix.de, peterz@infradead.org, hughd@google.com, aarcange@redhat.com, dan.j.williams@intel.com, jpoimboe@redhat.com, namit@vmware.com, gregkh@linuxfoundation.org, dwmw2@infradead.org, arjan@linux.intel.com, linux-kernel@vger.kernel.org, luto@kernel.org, dave.hansen@linux.intel.com, mingo@kernel.org, keescook@google.com, bp@alien8.de, hpa@zytor.com Reply-To: jgross@suse.com, vbabka@suse.cz, torvalds@linux-foundation.org, peterz@infradead.org, hughd@google.com, tglx@linutronix.de, dan.j.williams@intel.com, aarcange@redhat.com, namit@vmware.com, jpoimboe@redhat.com, arjan@linux.intel.com, gregkh@linuxfoundation.org, dwmw2@infradead.org, luto@kernel.org, linux-kernel@vger.kernel.org, dave.hansen@linux.intel.com, hpa@zytor.com, keescook@google.com, bp@alien8.de, mingo@kernel.org In-Reply-To: <20180420222026.D0B4AAC9@viggo.jf.intel.com> References: <20180420222026.D0B4AAC9@viggo.jf.intel.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/pti] x86/pti: Disallow global kernel text with RANDSTRUCT Git-Commit-ID: 26d35ca6c3776784f8156e1d6f80cc60d9a2a915 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 26d35ca6c3776784f8156e1d6f80cc60d9a2a915 Gitweb: https://git.kernel.org/tip/26d35ca6c3776784f8156e1d6f80cc60d9a2a915 Author: Dave Hansen AuthorDate: Fri, 20 Apr 2018 15:20:26 -0700 Committer: Thomas Gleixner CommitDate: Tue, 24 Apr 2018 09:50:54 +0200 x86/pti: Disallow global kernel text with RANDSTRUCT RANDSTRUCT derives its hardening benefits from the attacker's lack of knowledge about the layout of kernel data structures. Keep the kernel image non-global in cases where RANDSTRUCT is in use to help keep the layout a secret. Fixes: 8c06c7740 (x86/pti: Leave kernel text global for !PCID) Reported-by: Kees Cook Signed-off-by: Dave Hansen Signed-off-by: Thomas Gleixner Acked-by: Ingo Molnar Cc: Andrea Arcangeli Cc: Juergen Gross Cc: Josh Poimboeuf Cc: Greg Kroah-Hartman Cc: Peter Zijlstra Cc: David Woodhouse Cc: Hugh Dickins Cc: linux-mm@kvack.org Cc: Linus Torvalds Cc: Borislav Petkov Cc: Andy Lutomirski Cc: Nadav Amit Cc: Dan Williams Cc: Arjan van de Ven Cc: Vlastimil Babka Link: https://lkml.kernel.org/r/20180420222026.D0B4AAC9@viggo.jf.intel.com --- arch/x86/mm/pti.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/arch/x86/mm/pti.c b/arch/x86/mm/pti.c index ae3eb4f5d53b..4d418e705878 100644 --- a/arch/x86/mm/pti.c +++ b/arch/x86/mm/pti.c @@ -421,6 +421,16 @@ static inline bool pti_kernel_image_global_ok(void) if (boot_cpu_has(X86_FEATURE_K8)) return false; + /* + * RANDSTRUCT derives its hardening benefits from the + * attacker's lack of knowledge about the layout of kernel + * data structures. Keep the kernel image non-global in + * cases where RANDSTRUCT is in use to help keep the layout a + * secret. + */ + if (IS_ENABLED(CONFIG_GCC_PLUGIN_RANDSTRUCT)) + return false; + return true; }