From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kees Cook Date: Tue, 9 Jan 2018 12:55:58 -0800 Message-Id: <1515531365-37423-30-git-send-email-keescook@chromium.org> In-Reply-To: <1515531365-37423-1-git-send-email-keescook@chromium.org> References: <1515531365-37423-1-git-send-email-keescook@chromium.org> Subject: [kernel-hardening] [PATCH 29/36] x86: Implement thread_struct whitelist for hardened usercopy 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 , Linus Torvalds , David Windsor , Alexander Viro , Andrew Morton , Christoph Hellwig , Christoph Lameter , "David S. Miller" , Laura Abbott , Mark Rutland , "Martin K. Petersen" , Paolo Bonzini , Christian Borntraeger , Christoffer Dall , Dave Kleikamp , Jan Kara , Luis de Bethencourt , Marc Zyngier , Rik van Riel , Matthew Garrett , linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, netdev@vger.kernel.org, linux-mm@kvack.org, kernel-hardening@lists.openwall.com List-ID: 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 Acked-by: Rik van Riel --- 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 8eed3f94bfc7..9ac4ac1a856b 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -116,6 +116,7 @@ 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 cc16fa882e3e..2b037b7fe0eb 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -492,6 +492,14 @@ 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