lkml.org 
[lkml]   [2022]   [May]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH -next] exec: Remove redundant check in do_open_execat/uselib
On Wed, 18 May 2022 12:17:45 -0700 Kees Cook <keescook@chromium.org> wrote:

> > > - /*
> > > - * may_open() has already checked for this, so it should be
> > > - * impossible to trip now. But we need to be extra cautious
> > > - * and check again at the very end too.
> > > - */
> > > - error = -EACCES;
> > > - if (WARN_ON_ONCE(!S_ISREG(file_inode(file)->i_mode) ||
> > > - path_noexec(&file->f_path)))
> > > - goto exit;
> > > -
> >
> > Maybe we should retain the `goto exit'. The remount has now occurred,
> > so the execution attempt should be denied. If so, the comment should
> > be updated to better explain what's happening.
> >
> > I guess we'd still be racy against `mount -o exec', but accidentally
> > denying something seems less serious than accidentally permitting it.
>
> I'd like to leave this as-is, since we _do_ want to find the cases where
> we're about to allow an exec and a very important security check was NOT
> handled.

In which case we don't want the "_ONCE". If some app is hammering away
at this trying to hit a race window then the operator wants that log
flood.

Or,umm, fix the dang race?

\
 
 \ /
  Last update: 2022-05-18 21:29    [W:0.059 / U:1.364 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site