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SubjectRe: [PATCH v11 9/9] x86: Disallow vsyscall emulation when CET is enabled
On Mon, Aug 24, 2020 at 5:30 PM Yu-cheng Yu <yu-cheng.yu@intel.com> wrote:
>
> From: "H.J. Lu" <hjl.tools@gmail.com>
>
> Emulation of the legacy vsyscall page is required by some programs built
> before 2013. Newer programs after 2013 don't use it. Disallow vsyscall
> emulation when Control-flow Enforcement (CET) is enabled to enhance
> security.

NAK.

By all means disable execute emulation if CET-IBT is enabled at the
time emulation is attempted, and maybe even disable the vsyscall page
entirely if you can magically tell that CET-IBT will be enabled when a
process starts, but you don't get to just disable it outright on a
CET-enabled kernel.

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