lkml.org 
[lkml]   [2011]   [Nov]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 3/3] security: Yama: add ptrace relationship tracking interface
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.

Alexander


\
 
 \ /
  Last update: 2011-11-19 18:09    [W:0.057 / U:3.068 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site