linux-kernel - Re: [PATCH[RFC] kill sysrq-u (emergency remount r/o)

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:	Tue, 6 Feb 2007 09:44:38 +0000
From:	Christoph Hellwig <hch@...radead.org>
To:	Theodore Tso <tytso@....edu>,
	Jan Engelhardt <jengelh@...ux01.gwdg.de>,
	Christoph Hellwig <hch@....de>, akpm@...l.org,
	haveblue@...ibm.com, linux-fsdevel@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH[RFC] kill sysrq-u (emergency remount r/o)

On Mon, Feb 05, 2007 at 10:17:44PM -0500, Theodore Tso wrote:
> > sysrq+u is helpful. It is like \( sysrq+s && make sure no further writes
> > go to disk \).
> 
> I agree it is useful, but if we're going to do it we really should do
> it right.  We should have real revoke() functionality on file
> descriptors, which revokes all of the mmap()'s (any attempt to write
> into a previously read/write mmap will cause a SEGV) as well as
> changing f_mode, and then use that to implement emergency read-only
> remount.

Revoke is only part of it.  What we really need is proper forced unmount
support.  That means revoking any kind of userspace access, blocking new
access and making sure the ondisk image is coherent.  This would definitly
be a useful feature, but it's a lot of work.
-
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/