linux-kernel - Re: [PATCH 6/7] x86/boot/compressed/64: Check SEV encryption in 32-bit boot-path

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] [day] [month] [year] [list]

Message-ID: <YEdHvAWaWv8YDiUB@8bytes.org>
Date:   Tue, 9 Mar 2021 11:02:36 +0100
From:   Joerg Roedel <joro@...tes.org>
To:     Borislav Petkov <bp@...en8.de>
Cc:     x86@...nel.org, Joerg Roedel <jroedel@...e.de>, hpa@...or.com,
        Andy Lutomirski <luto@...nel.org>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Jiri Slaby <jslaby@...e.cz>,
        Dan Williams <dan.j.williams@...el.com>,
        Tom Lendacky <thomas.lendacky@....com>,
        Juergen Gross <jgross@...e.com>,
        Kees Cook <keescook@...omium.org>,
        David Rientjes <rientjes@...gle.com>,
        Cfir Cohen <cfir@...gle.com>,
        Erdem Aktas <erdemaktas@...gle.com>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Mike Stunes <mstunes@...are.com>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Martin Radev <martin.b.radev@...il.com>,
        Arvind Sankar <nivedita@...m.mit.edu>,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        virtualization@...ts.linux-foundation.org
Subject: Re: [PATCH 6/7] x86/boot/compressed/64: Check SEV encryption in
 32-bit boot-path

On Tue, Mar 02, 2021 at 08:43:53PM +0100, Borislav Petkov wrote:
> On Wed, Feb 10, 2021 at 11:21:34AM +0100, Joerg Roedel wrote:
> > +	/*
> > +	 * Store the sme_me_mask as an indicator that SEV is active. It will be
> > +	 * set again in startup_64().
> 
> So why bother? Or does something needs it before that?

This was actually a bug. The startup32_check_sev_cbit() needs something
to skip the check when SEV is not active. Therefore the value is set
here in sme_me_mask, but the function later checks sev_status.

I fixed it by setting sev_status to 1 here (indicates SEV is active).

Regards,

	Joerg