lkml.org 
[lkml]   [2011]   [Nov]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    SubjectRe: [PATCH 3/3] security: Yama: add ptrace relationship tracking interface
    From
    On Sat, Nov 19, 2011 at 8:59 AM, Solar Designer <solar@openwall.com> wrote:
    > On Sat, Nov 19, 2011 at 08:30:58PM +0400, Vasiliy Kulikov wrote:
    >> On Wed, Oct 26, 2011 at 16:49 -0700, Kees Cook wrote:
    >> > +   if (mode == PTRACE_MODE_ATTACH &&
    >> > +       ptrace_scope &&
    >> > +       !capable(CAP_SYS_PTRACE) &&
    >> > +       !task_is_descendant(current, child) &&
    >> > +       !ptracer_exception_found(current, child))
    >> > +           rc = -EPERM;
    >>
    >> capable() is better to put after all other tests
    >
    > Right, but...
    >
    >> as a failed capable()
    >> might emit a false positive warning into logs or something.
    >
    > ...primarily for another reason: a successful capable() sets
    > PF_SUPERPRIV, whereas the permission might have been granted without
    > capable() as well.  The PF_SUPERPRIV flag is visible via BSD process
    > accounting.

    Fair point, I'll move it. I had to go look up an earlier thread since
    this was ringing a bell, but in there I was talking about moving it to
    the end of the tests too. :)

    https://lkml.org/lkml/2010/6/30/5

    -Kees

    --
    Kees Cook
    ChromeOS Security
    --
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2011-11-21 19:43    [W:0.024 / U:30.472 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site