On Mon, Dec 04, 2017 at 03:07:29PM +0100, Thomas Gleixner wrote: > From: Andy Lutomirski <[email protected]> > > The TSS is a fairly juicy target for exploits, and, now that the TSS > is in the cpu_entry_area, it's no longer protected by kASLR. Make it > read-only on x86_64. > > On x86_32, it can't be RO because it's written by the CPU during task > switches, and we use a task gate for double faults. I'd also be > nervous about errata if we tried to make it RO even on configurations > without double fault handling. > > [ tglx: AMD confirmed that there is no problem on 64bit with TSS RO. So > it's probably safe to assume that it's a non issue, though Intel > might have been creative in that area. Still waiting for > confirmation. ] > > Signed-off-by: Andy Lutomirski <[email protected]> > Signed-off-by: Thomas Gleixner <[email protected]> > Cc: Kees Cook <[email protected]> > Cc: Peter Zijlstra <[email protected]> > Cc: Brian Gerst <[email protected]> > Cc: David Laight <[email protected]> > Cc: Borislav Petkov <[email protected]> > Link: > https://lkml.kernel.org/r/7d2f65f86a46e3489ba996932554485c3d345632.1512109321.git.l...@kernel.org > > --- > arch/x86/entry/entry_32.S | 4 ++-- > arch/x86/entry/entry_64.S | 8 ++++---- > arch/x86/include/asm/fixmap.h | 13 +++++++++---- > arch/x86/include/asm/processor.h | 17 ++++++++--------- > arch/x86/include/asm/switch_to.h | 4 ++-- > arch/x86/include/asm/thread_info.h | 2 +- > arch/x86/kernel/asm-offsets.c | 5 ++--- > arch/x86/kernel/asm-offsets_32.c | 4 ++-- > arch/x86/kernel/cpu/common.c | 29 +++++++++++++++++++---------- > arch/x86/kernel/ioport.c | 2 +- > arch/x86/kernel/process.c | 6 +++--- > arch/x86/kernel/process_32.c | 2 +- > arch/x86/kernel/process_64.c | 2 +- > arch/x86/kernel/traps.c | 4 ++-- > arch/x86/lib/delay.c | 4 ++-- > arch/x86/xen/enlighten_pv.c | 2 +- > 16 files changed, 60 insertions(+), 48 deletions(-)
Reviewed-by: Borislav Petkov <[email protected]> -- Regards/Gruss, Boris. SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg) --
