On Mon, Mar 6, 2023 at 5:10 AM Borislav Petkov <bp@xxxxxxxxx> wrote: > > On Mon, Feb 27, 2023 at 02:29:40PM -0800, Rick Edgecombe wrote: > > The x86 Control-flow Enforcement Technology (CET) feature includes a new > > type of memory called shadow stack. This shadow stack memory has some > > unusual properties, which requires some core mm changes to function > > properly. > > > > Shadow stack memory is writable only in very specific, controlled ways. > > However, since it is writable, the kernel treats it as such. As a result > ^ > , > > > there remain many ways for userspace to trigger the kernel to write to > > shadow stack's via get_user_pages(, FOLL_WRITE) operations. To make this a Is there an alternate mechanism, or do we still want to allow FOLL_FORCE so that debuggers can write it? --Andy
