linux-kernel - Re: [PATCH v28 04/10] x86/cet/ibt: Disable IBT for ia32

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: <3318ca57-7ac3-8296-f9ae-0ae83d5f95dd@kernel.org>
Date:   Mon, 9 Aug 2021 16:04:18 -0700
From:   Andy Lutomirski <luto@...nel.org>
To:     Yu-cheng Yu <yu-cheng.yu@...el.com>, 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-doc@...r.kernel.org, linux-mm@...ck.org,
        linux-arch@...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>,
        "H.J. Lu" <hjl.tools@...il.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>,
        Dave Martin <Dave.Martin@....com>,
        Weijiang Yang <weijiang.yang@...el.com>,
        Pengfei Xu <pengfei.xu@...el.com>,
        Haitao Huang <haitao.huang@...el.com>,
        Rick P Edgecombe <rick.p.edgecombe@...el.com>
Subject: Re: [PATCH v28 04/10] x86/cet/ibt: Disable IBT for ia32

On 7/22/21 1:57 PM, Yu-cheng Yu wrote:
> In a signal, a task's IBT status needs to be saved to the signal frame, and
> later restored in sigreturn.  For the purpose, previous versions of the
> series add a new struct to the signal frame.  However, a new signal frame
> format (or re-using a reserved space) introduces complex compatibility
> issues.
> 
> In the discussion (see link below), Andy Lutomirski proposed using a
> ucontext flag.  The approach is clean and eliminates most compatibility
> issues.
> 
> However, a legacy IA32 signal frame does not have ucontext and cannot
> support a uc flag.  Thus,
> 
> - Disable IBT for ia32.
> - In ia32 sigreturn, verify ibt is disabled.

Acked-by: Andy Lutomirski <luto@...nel.org>