lkml.org 
[lkml]   [2007]   [May]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [rfc] increase struct page size?!
On Mon, May 21, 2007 at 11:12:59AM +0200, Helge Hafting wrote:
> Andrew Morton wrote:
> >On Sat, 19 May 2007 11:15:01 -0700 William Lee Irwin III
> ><wli@holomorphy.com> wrote:
> >
> >
> >>Much the same holds for the atomic_t's; 32 + PAGE_SHIFT is
> >>44 bits or more, about as much as is possible, and one reference per
> >>page per page is not even feasible. Full-length atomic_t's are just
> >>not necessary.
> >>
> >
> >You can overflow a page's refcount by mapping it 4G times. That requires
> >32GB of pagetable memory. It's quite feasible with remap_file_pages().
> >
> But do anybody ever need to do that?
> Such an attack is easily thwarted by refusing to map it more
> than, say 3G times?

That still allows you to DoS the page.

-
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: 2007-05-21 11:47    [W:0.152 / U:0.552 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site