Re: [PATCH] x86/vsyscall: Remove CONFIG_LEGACY_VSYSCALL_EMULATE

[Kees Cook]

On Wed, May 11, 2022 at 10:38:53AM -0700, Andy Lutomirski wrote:
> CONFIG_LEGACY_VSYSCALL_EMULATE is, as far as I know, only needed for the
> combined use of exotic and outdated debugging mechanisms with outdated
> binaries.  At this point, no one should be using it.  We would like to
> implement dynamic switching of vsyscalls, but this is much more
> complicated to support in EMULATE mode than XONLY mode.
> 
> So let's force all the distros off of EMULATE mode.  If anyone actually
> needs it, they can set vsyscall=emulate, and we can then get away with
> refusing to support newer security models if that option is set.
> 
> Cc: x86@xxxxxxxxxx
> Cc: Kees Cook <keescook@xxxxxxxxxxxx>
> Cc: Florian Weimer <fweimer@xxxxxxxxxx>
> Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx>

Sounds legit! Can we switch the default to "none" while we're at it?

Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>

-- 
Kees Cook