lkml.org 
[lkml]   [2018]   [Jun]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH 00/10] Control Flow Enforcement - Part (3)
From
Date
On Thu, 2018-06-14 at 07:56 -0700, Yu-cheng Yu wrote:
> On Thu, 2018-06-14 at 11:07 +1000, Balbir Singh wrote:
> > On Tue, 2018-06-12 at 08:03 -0700, Yu-cheng Yu wrote:
> > > On Tue, 2018-06-12 at 20:56 +1000, Balbir Singh wrote:
> > > >
> > > > On 08/06/18 00:37, Yu-cheng Yu wrote:
> > > > > This series introduces CET - Shadow stack
> > > > >
> > > > > At the high level, shadow stack is:
> > > > >
> > > > > Allocated from a task's address space with vm_flags VM_SHSTK;
> > > > > Its PTEs must be read-only and dirty;
> > > > > Fixed sized, but the default size can be changed by sys admin.
> > > > >
> > > > > For a forked child, the shadow stack is duplicated when the next
> > > > > shadow stack access takes place.
> > > > >
> > > > > For a pthread child, a new shadow stack is allocated.
> > > > >
> > > > > The signal handler uses the same shadow stack as the main program.
> > > > >
> > > >
> > > > Even with sigaltstack()?
> > > >
> > >
> > > Yes.
> >
> > I am not convinced that it would work, as we switch stacks, oveflow might
> > be an issue. I also forgot to bring up setcontext(2), I presume those
> > will get new shadow stacks
>
> Do you mean signal stack/sigaltstack overflow or swapcontext in a signal
> handler?
>

I meant any combination of that. If there is a user space threads implementation that uses sigaltstack for switching threads

Balbir Singh.

> Yu-cheng
>

\
 
 \ /
  Last update: 2018-06-17 05:16    [W:0.117 / U:0.284 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site