linux-kernel - Re: Replacement for page fault notifiers?

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: <1199908703.6734.133.camel@pasglop>
Date:	Thu, 10 Jan 2008 06:58:23 +1100
From:	Benjamin Herrenschmidt <benh@...nel.crashing.org>
To:	Christoph Hellwig <hch@...radead.org>
Cc:	Pavel Roskin <proski@....org>, Dave Airlie <airlied@...il.com>,
	Pekka Paalanen <pq@....fi>, linux-kernel@...r.kernel.org,
	jbeulich@...ell.com
Subject: Re: Replacement for page fault notifiers?


On Wed, 2008-01-09 at 18:21 +0000, Christoph Hellwig wrote:
> On Wed, Jan 09, 2008 at 01:18:44PM -0500, Pavel Roskin wrote:
> > notification without patching the kernel.  But if no such solution is
> > found, I would also support reverting the patch that removed fault
> > notifiers on i386.
> 
> With your fixation on not patching the kernel you sound like a windows
> developer.  There is no problem with patching the kernel, but the best
> patching of that kernel is that which happens upstream so please folks
> start submitting an mmiotrace variant for kernel inclusion.
> 
> Then again I don't quite get why you absolutely want to track pagefaults
> anyway.  Just hooking into ioremap and read*/write* and iomap +
> ioread*/iowrite* would be much easier and also a lot faster.  It would
> also allow adding a nice sysfs attribute to enable this per-device.

Because binary drivers don't use ioread/iowrite/readX/writeX (or if they
do, they've long been inlined in the blob). The only solution is to map
things as non-accessible and trap the page faults.

It's a sane thing to do, Christoph, I don't think it's a unreasonable
request to put the hooks back in.

Cheers,
Ben.


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/