linux-kernel - Re: [PATCH v4 0/4] Application Data Integrity feature introduced by SPARC M7

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]

Date:   Mon, 16 Jan 2017 23:42:13 -0500 (EST)
From:   David Miller <davem@...emloft.net>
To:     dave.hansen@...ux.intel.com
Cc:     khalid.aziz@...cle.com, corbet@....net, arnd@...db.de,
        akpm@...ux-foundation.org, hpa@...or.com, viro@...iv.linux.org.uk,
        nitin.m.gupta@...cle.com, chris.hyser@...cle.com,
        tushar.n.dave@...cle.com, sowmini.varadhan@...cle.com,
        mike.kravetz@...cle.com, adam.buchbinder@...il.com,
        minchan@...nel.org, hughd@...gle.com,
        kirill.shutemov@...ux.intel.com, keescook@...omium.org,
        allen.pais@...cle.com, aryabinin@...tuozzo.com,
        atish.patra@...cle.com, joe@...ches.com, pmladek@...e.com,
        jslaby@...e.cz, cmetcalf@...lanox.com,
        paul.gortmaker@...driver.com, mhocko@...e.com, jmarchan@...hat.com,
        lstoakes@...il.com, 0x7f454c46@...il.com, vbabka@...e.cz,
        tglx@...utronix.de, mingo@...hat.com, dan.j.williams@...el.com,
        iamjoonsoo.kim@....com, mgorman@...hsingularity.net,
        vdavydov.dev@...il.com, hannes@...xchg.org, namit@...are.com,
        linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
        sparclinux@...r.kernel.org, linux-arch@...r.kernel.org,
        x86@...nel.org, linux-mm@...ck.org
Subject: Re: [PATCH v4 0/4] Application Data Integrity feature introduced
 by SPARC M7

From: Dave Hansen <dave.hansen@...ux.intel.com>
Date: Wed, 11 Jan 2017 08:33:30 -0800

> Is there a cost in the hardware associated with doing this "ADI
> checking"?  For instance, instead of having this new mprotect()
> interface, why not just always set TTE.mcd on all PTEs?

If we did this then for every page mapped into userspace we'd have
to explicitly set all of the tags to zero, otherwise we'd get TAG
mismatch exceptions.

That would be like clearing the every mapped anonymous page twice, or
worse.