On Thu, 2018-08-30 at 10:33 -0700, Dave Hansen wrote: > On 08/30/2018 10:26 AM, Yu-cheng Yu wrote: > > > > We don't have the guard page now, but there is a shadow stack > > token > > there, which cannot be used as a return address. > The overall concern is that we could overflow into a page that we > did > not intend. Either another actual shadow stack or something that a > page > that the attacker constructed, like the transient scenario Jann > described. > A task could go beyond the bottom of its shadow stack by doing either 'ret' or 'incssp'. If it is the 'ret' case, the token prevents it. If it is the 'incssp' case, a guard page cannot prevent it entirely, right? Yu-cheng
