linux-kernel - Re: [PATCH RFC V2 17/17] x86/entry: Preserve PKRS MSR across exceptions

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: <CALCETrVe1i5JdyzD_BcctxQJn+ZE3T38EFPgjxN1F577M36g+w@mail.gmail.com>
Date:   Wed, 22 Jul 2020 09:21:43 -0700
From:   Andy Lutomirski <luto@...nel.org>
To:     Weiny Ira <ira.weiny@...el.com>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Andy Lutomirski <luto@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        X86 ML <x86@...nel.org>,
        Dan Williams <dan.j.williams@...el.com>,
        Vishal Verma <vishal.l.verma@...el.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Fenghua Yu <fenghua.yu@...el.com>,
        "open list:DOCUMENTATION" <linux-doc@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        linux-nvdimm <linux-nvdimm@...ts.01.org>,
        Linux FS Devel <linux-fsdevel@...r.kernel.org>,
        Linux-MM <linux-mm@...ck.org>,
        "open list:KERNEL SELFTEST FRAMEWORK" 
        <linux-kselftest@...r.kernel.org>
Subject: Re: [PATCH RFC V2 17/17] x86/entry: Preserve PKRS MSR across exceptions

On Fri, Jul 17, 2020 at 12:21 AM <ira.weiny@...el.com> wrote:
>
> From: Ira Weiny <ira.weiny@...el.com>
>
> The PKRS MSR is not managed by XSAVE.  It is already preserved through a
> context switch but this support leaves exception handling code open to
> memory accesses which the interrupted process has allowed.
>
> Close this hole by preserve the current task's PKRS MSR, reset the PKRS
> MSR value on exception entry, and then restore the state on exception
> exit.

Should this live in pt_regs?

--Andy