linux-kernel - Re: [PATCH v4 15/75] x86/boot/compressed/64: Always switch to own page-table

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: <202007141823.326D9DC102@keescook>
Date:   Tue, 14 Jul 2020 18:23:47 -0700
From:   Kees Cook <keescook@...omium.org>
To:     Joerg Roedel <joro@...tes.org>
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>,
        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>,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        virtualization@...ts.linux-foundation.org
Subject: Re: [PATCH v4 15/75] x86/boot/compressed/64: Always switch to own
 page-table

On Tue, Jul 14, 2020 at 02:08:17PM +0200, Joerg Roedel wrote:
> From: Joerg Roedel <jroedel@...e.de>
> 
> When booted through startup_64 the kernel keeps running on the EFI
> page-table until the KASLR code sets up its own page-table. Without
> KASLR the pre-decompression boot code never switches off the EFI
> page-table. Change that by unconditionally switching to a kernel
> controlled page-table after relocation.
> 
> This makes sure we can make changes to the mapping when necessary, for
> example map pages unencrypted in SEV and SEV-ES guests.
> 
> Also remove the debug_putstr() calls in initialize_identity_maps()
> because the function now runs before console_init() is called.
> 
> Signed-off-by: Joerg Roedel <jroedel@...e.de>

Reviewed-by: Kees Cook <keescook@...omium.org>

-- 
Kees Cook