lkml.org 
[lkml]   [2018]   [Jun]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] ksys_mount: check for permissions before resource allocation
On Tue, Jun 05, 2018 at 04:07:15PM +0400, Ilya Matveychikov wrote:

> > If you depend upon preventing kmalloc'ed temporary allocations filled
> > with user-supplied data, you are screwed, plain and simple. It really can't
> > be prevented, in a lot of ways that are much less exotic than mount(2).
> > Most of syscall arguments are copied in, before we get any permission
> > checks. It does happen and it will happen - examining them while they are
> > still in userland is a nightmare in a lot of respects, starting with
> > security.
>
> I agree that it’s impossible to completely avoid this kind of allocations
> and examining data in user-land will be the bigger problem than copying
> arguments to the kernel. But aside of that what’s wrong with the idea of
> having the permission check before doing any kind of work?

Presenting that as mitigating a vulnerability. It's neither better nor worse
in that respect than the original.

\
 
 \ /
  Last update: 2018-06-05 14:34    [W:0.036 / U:59.632 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site