linux-kernel - Re: [PATCH v8 10/11] arm64/kasan: explicitly zero kasan shadow memory

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]

Date:   Fri, 15 Sep 2017 22:51:48 +0100
From:   Mark Rutland <mark.rutland@....com>
To:     Pavel Tatashin <pasha.tatashin@...cle.com>
Cc:     linux-kernel@...r.kernel.org, sparclinux@...r.kernel.org,
        linux-mm@...ck.org, linuxppc-dev@...ts.ozlabs.org,
        linux-s390@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        x86@...nel.org, kasan-dev@...glegroups.com, borntraeger@...ibm.com,
        heiko.carstens@...ibm.com, davem@...emloft.net,
        willy@...radead.org, mhocko@...nel.org, ard.biesheuvel@...aro.org,
        will.deacon@....com, catalin.marinas@....com, sam@...nborg.org,
        mgorman@...hsingularity.net, Steven.Sistare@...cle.com,
        daniel.m.jordan@...cle.com, bob.picco@...cle.com
Subject: Re: [PATCH v8 10/11] arm64/kasan: explicitly zero kasan shadow memory

On Fri, Sep 15, 2017 at 05:20:59PM -0400, Pavel Tatashin wrote:
> Hi Mark,
> 
> I had this option  back upto version 3, where zero flag was passed into
> vmemmap_alloc_block(), but I was asked to remove it, because it required too
> many changes in other places.

Ok. Sorry for bringing back a point that had already been covered.

> So, the current approach is cleaner, but the idea is that kasan should use
> its own version of vmemmap_populate() for both x86 and ARM, but I think it is
> outside of the scope of this work.

I appreciate that this is unrelated to your ultimate goal, and that this is
somewhat frustrating given the KASAN code is arguably abusing the
vmemmap_populate() interface.

However, I do think we need to migrate the KASAN code to a proper interface
immediately, rather than making it worse in the interim.

> If you think I should add these function in this project, than sure I can
> send a new version with kasanmap_populate() functions.

I would very much appreciate if you could send a version with a
kasan_map_populate() interface. I'm more than happy to review/test that portion
of the series, or to help if there's some problem which makes that difficult.

Thanks,
Mark.