Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751537AbdH1Vxz (ORCPT ); Mon, 28 Aug 2017 17:53:55 -0400 Received: from mail-pg0-f47.google.com ([74.125.83.47]:35484 "EHLO mail-pg0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751190AbdH1Vxw (ORCPT ); Mon, 28 Aug 2017 17:53:52 -0400 From: Kees Cook To: linux-kernel@vger.kernel.org Cc: Kees Cook , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, Borislav Petkov , Andy Lutomirski , Mathias Krause , linux-mm@kvack.org, kernel-hardening@lists.openwall.com, David Windsor Subject: [PATCH v2 27/30] x86: Implement thread_struct whitelist for hardened usercopy Date: Mon, 28 Aug 2017 14:35:08 -0700 Message-Id: <1503956111-36652-28-git-send-email-keescook@chromium.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1503956111-36652-1-git-send-email-keescook@chromium.org> References: <1503956111-36652-1-git-send-email-keescook@chromium.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1608 Lines: 49 This whitelists the FPU register state portion of the thread_struct for copying to userspace, instead of the default entire struct. Cc: Thomas Gleixner Cc: Ingo Molnar Cc: "H. Peter Anvin" Cc: x86@kernel.org Cc: Borislav Petkov Cc: Andy Lutomirski Cc: Mathias Krause Signed-off-by: Kees Cook --- arch/x86/Kconfig | 1 + arch/x86/include/asm/processor.h | 8 ++++++++ 2 files changed, 9 insertions(+) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 781521b7cf9e..a8793721483c 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -113,6 +113,7 @@ config X86 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT select HAVE_ARCH_SECCOMP_FILTER + select HAVE_ARCH_THREAD_STRUCT_WHITELIST select HAVE_ARCH_TRACEHOOK select HAVE_ARCH_TRANSPARENT_HUGEPAGE select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index 028245e1c42b..dc52ba90f090 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -481,6 +481,14 @@ struct thread_struct { */ }; +/* Whitelist the FPU state from the task_struct for hardened usercopy. */ +static inline void arch_thread_struct_whitelist(unsigned long *offset, + unsigned long *size) +{ + *offset = offsetof(struct thread_struct, fpu.state); + *size = fpu_kernel_xstate_size; +} + /* * Thread-synchronous status. * -- 2.7.4