linux-kernel - Re: [RFC 05/10] x86/speculation: Add basic IBRS support infrastructure

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: <1516807081.13558.147.camel@infradead.org>
Date:   Wed, 24 Jan 2018 15:18:01 +0000
From:   David Woodhouse <dwmw2@...radead.org>
To:     Arjan van de Ven <arjan@...ux.intel.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        KarimAllah Ahmed <karahmed@...zon.de>,
        linux-kernel@...r.kernel.org, Andi Kleen <ak@...ux.intel.com>,
        Andrea Arcangeli <aarcange@...hat.com>,
        Andy Lutomirski <luto@...nel.org>,
        Ashok Raj <ashok.raj@...el.com>,
        Asit Mallick <asit.k.mallick@...el.com>,
        Borislav Petkov <bp@...e.de>,
        Dan Williams <dan.j.williams@...el.com>,
        Dave Hansen <dave.hansen@...el.com>,
        "H . Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...hat.com>,
        Janakarajan Natarajan <Janakarajan.Natarajan@....com>,
        Joerg Roedel <joro@...tes.org>,
        Jun Nakajima <jun.nakajima@...el.com>,
        Laura Abbott <labbott@...hat.com>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Radim Krčmář <rkrcmar@...hat.com>,
        Tim Chen <tim.c.chen@...ux.intel.com>,
        Tom Lendacky <thomas.lendacky@....com>, kvm@...r.kernel.org,
        x86@...nel.org
Subject: Re: [RFC 05/10] x86/speculation: Add basic IBRS support
 infrastructure

On Wed, 2018-01-24 at 07:09 -0800, Arjan van de Ven wrote:
> On 1/24/2018 1:10 AM, Greg Kroah-Hartman wrote:
> > Arjan, why do you think this can only be done as a whitelist?
>
> I suggested a minimum version list for those cpus that need it.
>
> microcode versions are tricky (and we've released betas etc etc with their own numbers)
> and as a result there might be several numbers that have those issues with their IBRS for the same F/M/S

I really think that's fine. Anyone who uses beta microcodes, should be
perfectly prepared to deal with the results. And probably *wanted* to
be able to actually test them, instead of having the kernel refuse to
do so.

So if there are beta microcodes floating around with numbers higher
than in Intel's currently-published list, which are not yet known to be
safe (or even if they're known not to be), that's absolutely OK.

If you're telling me that there will be *publicly* released microcodes
with version numbers higher than those in the list, which still have
the same issues... well, then I think Mr Shouty is going to come for
another visit.
Download attachment "smime.p7s" of type "application/x-pkcs7-signature" (5213 bytes)