This whitelists the FPU register state portion of the thread_struct for copying to userspace, instead of the default entire struct.
Cc: Thomas Gleixner <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Cc: [email protected] Cc: Borislav Petkov <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Mathias Krause <[email protected]> Signed-off-by: Kees Cook <[email protected]> Acked-by: Rik van Riel <[email protected]> --- 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 971feac13506..6642e8eaff45 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -114,6 +114,7 @@ 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 3fa26a61eabc..868235b967ed 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -488,6 +488,14 @@ 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
