From: Andy Lutomirski <luto@kernel.org>
To: Kees Cook <keescook@chromium.org>
Cc: Andy Lutomirski <luto@kernel.org>, X86 ML <x86@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Borislav Petkov <bp@alien8.de>,
Kernel Hardening <kernel-hardening@lists.openwall.com>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH 5/5] x86/vsyscall: Change the default vsyscall mode to xonly
Date: Thu, 13 Jun 2019 12:14:50 -0700 [thread overview]
Message-ID: <CALCETrUYNavL8pu4jQqJjoT=PdeRyjeoLDn=0r7h=2XsHDMezQ@mail.gmail.com> (raw)
In-Reply-To: <201906101344.018BE4C5C1@keescook>
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
next prev parent reply other threads:[~2019-06-13 19:15 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-10 20:25 [PATCH 0/5] vsyscall xonly mode Andy Lutomirski
2019-06-10 20:25 ` [PATCH 1/5] x86/vsyscall: Remove the vsyscall=native documentation Andy Lutomirski
2019-06-10 20:25 ` [PATCH 2/5] x86/vsyscall: Add a new vsyscall=xonly mode Andy Lutomirski
2019-06-10 20:43 ` Kees Cook
2019-06-13 19:08 ` Andy Lutomirski
2019-06-10 20:25 ` [PATCH 3/5] x86/vsyscall: Document odd #PF's error code for vsyscalls Andy Lutomirski
2019-06-10 20:40 ` Kees Cook
2019-06-13 19:07 ` Andy Lutomirski
2019-06-10 20:25 ` [PATCH 4/5] selftests/x86/vsyscall: Verify that vsyscall=none blocks execution Andy Lutomirski
2019-06-10 20:25 ` [PATCH 5/5] x86/vsyscall: Change the default vsyscall mode to xonly Andy Lutomirski
2019-06-10 20:44 ` Kees Cook
2019-06-13 19:14 ` Andy Lutomirski [this message]
2019-06-14 5:19 ` Kees Cook
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