Messages in this thread | | | From | Andy Lutomirski <> | Date | Thu, 13 Jun 2019 12:14:50 -0700 | Subject | Re: [PATCH 5/5] x86/vsyscall: Change the default vsyscall mode to xonly |
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On Mon, Jun 10, 2019 at 1:44 PM Kees Cook <keescook@chromium.org> wrote: > > On Mon, Jun 10, 2019 at 01:25:31PM -0700, Andy Lutomirski wrote: > > The use case for full emulation over xonly is very esoteric. Let's > > change the default to the safer xonly mode. > > Perhaps describe the esoteric cases here (and maybe in the Kconfig help > text)? That should a user determine if they actually need it. (What > would the failure under xonly look like for someone needing emulate?)
I added it to the Kconfig text.
Right now, the failure will just be a segfault. I could add some logic so that it would log "invalid read to vsyscall page -- fix your userspace or boot with vsyscall=emulate". Do you think that's important?
--Andy
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