Re: [PATCH v12 8/8] x86: Disallow vsyscall emulation when CET is enabled
From: H.J. Lu <hidden>
Date: 2020-09-18 21:06:40
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linux-arch, linux-doc, linux-mm, lkml
On Fri, Sep 18, 2020 at 2:00 PM Pavel Machek [off-list ref] wrote:
On Fri 2020-09-18 12:32:57, Dave Hansen wrote:quoted
On 9/18/20 12:23 PM, Yu-cheng Yu wrote:quoted
Emulation of the legacy vsyscall page is required by some programs built before 2013. Newer programs after 2013 don't use it. Disable vsyscall emulation when Control-flow Enforcement (CET) is enabled to enhance security.How does this "enhance security"? What is the connection between vsyscall emulation and CET?Boom. We don't break compatibility by default, and you should not tell people to enable CET by default if you plan to do this.
Nothing will be broken. CET enabled applications don't use/need vsyscall emulation. -- H.J.