linux-kernel - Re: [PATCHv5 02/19] mm: Do not use zero page in encrypted pages

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: <e09c67ab-38a7-5b76-29e6-a45627eec1e5@intel.com>
Date:   Wed, 18 Jul 2018 10:36:24 -0700
From:   Dave Hansen <dave.hansen@...el.com>
To:     "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
        Ingo Molnar <mingo@...hat.com>, x86@...nel.org,
        Thomas Gleixner <tglx@...utronix.de>,
        "H. Peter Anvin" <hpa@...or.com>,
        Tom Lendacky <thomas.lendacky@....com>
Cc:     Kai Huang <kai.huang@...ux.intel.com>,
        Jacob Pan <jacob.jun.pan@...ux.intel.com>,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org
Subject: Re: [PATCHv5 02/19] mm: Do not use zero page in encrypted pages

On 07/17/2018 04:20 AM, Kirill A. Shutemov wrote:
> Zero page is not encrypted and putting it into encrypted VMA produces
> garbage.
> 
> We can map zero page with KeyID-0 into an encrypted VMA, but this would
> be violation security boundary between encryption domains.

Why?  How is it a violation?

It only matters if they write secrets.  They can't write secrets to the
zero page.

Is this only because you accidentally inherited ->vm_page_prot on the
zero page PTE?