Messages in this thread | | | Date | Mon, 21 Nov 2011 10:40:25 -0800 | Subject | Re: [PATCH 3/3] security: Yama: add ptrace relationship tracking interface | From | Kees Cook <> |
| |
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/
| |