linux-kernel - Re: [PATCH v26 0/9] Control-flow Enforcement: Indirect Branch Tracking

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAMe9rOp7FauoqQ0vx+ZVPGOE9+ABspheuGLc++Chj_goE5HvWA@mail.gmail.com>
Date:   Wed, 28 Apr 2021 07:56:38 -0700
From:   "H.J. Lu" <hjl.tools@...il.com>
To:     Andy Lutomirski <luto@...nel.org>
Cc:     David Laight <David.Laight@...lab.com>,
        Yu-cheng Yu <yu-cheng.yu@...el.com>,
        "x86@...nel.org" <x86@...nel.org>,
        "H. Peter Anvin" <hpa@...or.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-doc@...r.kernel.org" <linux-doc@...r.kernel.org>,
        "linux-mm@...ck.org" <linux-mm@...ck.org>,
        "linux-arch@...r.kernel.org" <linux-arch@...r.kernel.org>,
        "linux-api@...r.kernel.org" <linux-api@...r.kernel.org>,
        Arnd Bergmann <arnd@...db.de>,
        Balbir Singh <bsingharora@...il.com>,
        Borislav Petkov <bp@...en8.de>,
        Cyrill Gorcunov <gorcunov@...il.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Eugene Syromiatnikov <esyr@...hat.com>,
        Florian Weimer <fweimer@...hat.com>,
        Jann Horn <jannh@...gle.com>, Jonathan Corbet <corbet@....net>,
        Kees Cook <keescook@...omium.org>,
        Mike Kravetz <mike.kravetz@...cle.com>,
        Nadav Amit <nadav.amit@...il.com>,
        Oleg Nesterov <oleg@...hat.com>, Pavel Machek <pavel@....cz>,
        Peter Zijlstra <peterz@...radead.org>,
        Randy Dunlap <rdunlap@...radead.org>,
        "Ravi V. Shankar" <ravi.v.shankar@...el.com>,
        Vedvyas Shanbhogue <vedvyas.shanbhogue@...el.com>,
        Dave Martin <Dave.Martin@....com>,
        Weijiang Yang <weijiang.yang@...el.com>,
        Pengfei Xu <pengfei.xu@...el.com>,
        Haitao Huang <haitao.huang@...el.com>
Subject: Re: [PATCH v26 0/9] Control-flow Enforcement: Indirect Branch Tracking

On Wed, Apr 28, 2021 at 7:52 AM Andy Lutomirski <luto@...nel.org> wrote:
>
> On Wed, Apr 28, 2021 at 7:48 AM David Laight <David.Laight@...lab.com> wrote:
> >
> > From: Yu-cheng Yu
> > > Sent: 27 April 2021 21:47
> > >
> > > Control-flow Enforcement (CET) is a new Intel processor feature that blocks
> > > return/jump-oriented programming attacks.  Details are in "Intel 64 and
> > > IA-32 Architectures Software Developer's Manual" [1].
> > ...
> >
> > Does this feature require that 'binary blobs' for out of tree drivers
> > be compiled by a version of gcc that adds the ENDBRA instructions?
> >
> > If enabled for userspace, what happens if an old .so is dynamically
> > loaded?

CET will be disabled by ld.so in this case.

> > Or do all userspace programs and libraries have to have been compiled
> > with the ENDBRA instructions?

Correct.  ld and ld.so check this.

> If you believe that the userspace tooling for the legacy IBT table
> actually works, then it should just work.  Yu-cheng, etc: how well
> tested is it?
>

Legacy IBT bitmap isn't unused since it doesn't cover legacy codes
generated by legacy JITs.

-- 
H.J.