Messages in this thread | | | From | Andy Lutomirski <> | Date | Mon, 6 Mar 2023 10:15:13 -0800 | Subject | Re: [PATCH v7 24/41] mm: Don't allow write GUPs to shadow stack memory |
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On Mon, Mar 6, 2023 at 5:10 AM Borislav Petkov <bp@alien8.de> 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
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