lkml.org 
[lkml]   [2021]   [Feb]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH v19 24/25] x86/cet/shstk: Add arch_prctl functions for shadow stack
    On Thu, Feb 04, 2021 at 03:41:59PM -0800, Yu, Yu-cheng wrote:
    > On 2/4/2021 12:35 PM, Kees Cook wrote:
    > > On Wed, Feb 03, 2021 at 02:55:46PM -0800, Yu-cheng Yu wrote:
    > > > arch_prctl(ARCH_X86_CET_STATUS, u64 *args)
    > > > Get CET feature status.
    > > >
    > > > The parameter 'args' is a pointer to a user buffer. The kernel returns
    > > > the following information:
    > > >
    > > > *args = shadow stack/IBT status
    > > > *(args + 1) = shadow stack base address
    > > > *(args + 2) = shadow stack size
    > >
    > > What happens if this needs to grow in the future? Should the first u64
    > > contain the array size?
    > >
    > > Otherwise, looks sensible.
    > >
    > > -Kees
    > >
    >
    > The first item is a bitmap, and there are two possible bits. Should there
    > be a need, we can then do things about it. My thought at the moment is, we
    > may not meet the situation. Can we keep this for now?

    Ah, good point. Yes, since that's a bitmap it ends up describing what
    follows. This is fine as-is. Thanks!

    Reviewed-by: Kees Cook <keescook@chromium.org>


    --
    Kees Cook

    \
     
     \ /
      Last update: 2021-02-05 19:32    [W:3.538 / U:0.008 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site