From: Kees Cook <keescook@chromium.org>
To: Andy Lutomirski <luto@kernel.org>
Cc: 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: Mon, 10 Jun 2019 13:44:55 -0700 [thread overview]
Message-ID: <201906101344.018BE4C5C1@keescook> (raw)
In-Reply-To: <25fd7036cefca16c68ecd990e05e05a8ad8fe8b2.1560198181.git.luto@kernel.org>
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?)
-Kees
>
> Cc: Kees Cook <keescook@chromium.org>
> Cc: Borislav Petkov <bp@alien8.de>
> Cc: Kernel Hardening <kernel-hardening@lists.openwall.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Signed-off-by: Andy Lutomirski <luto@kernel.org>
> ---
> arch/x86/Kconfig | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index 054033cc4b1b..e56f33e6b045 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -2280,7 +2280,7 @@ config COMPAT_VDSO
> choice
> prompt "vsyscall table for legacy applications"
> depends on X86_64
> - default LEGACY_VSYSCALL_EMULATE
> + default LEGACY_VSYSCALL_XONLY
> help
> Legacy user code that does not know how to find the vDSO expects
> to be able to issue three syscalls by calling fixed addresses in
> --
> 2.21.0
>
--
Kees Cook
next prev parent reply other threads:[~2019-06-10 20:44 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 [this message]
2019-06-13 19:14 ` Andy Lutomirski
2019-06-14 5:19 ` Kees Cook
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=201906101344.018BE4C5C1@keescook \
--to=keescook@chromium.org \
--cc=bp@alien8.de \
--cc=kernel-hardening@lists.openwall.com \
--cc=linux-kernel@vger.kernel.org \
--cc=luto@kernel.org \
--cc=peterz@infradead.org \
--cc=tglx@linutronix.de \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).