From: Eric Blake <eblake@redhat.com>
To: Stefan Hajnoczi <stefanha@redhat.com>
Cc: "Kevin Wolf" <kwolf@redhat.com>,
"Kashyap Chamarthy" <kashyap.cv@gmail.com>,
qemu-devel@nongnu.org, "Benoît Canet" <benoit@irqsave.net>
Subject: Re: [Qemu-devel] [PATCH] qemu-img: Add --backing-chain option to info command
Date: Fri, 12 Oct 2012 08:24:27 -0600 [thread overview]
Message-ID: <5078281B.3090702@redhat.com> (raw)
In-Reply-To: <1350050969-14034-1-git-send-email-stefanha@redhat.com>
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On 10/12/2012 08:09 AM, Stefan Hajnoczi wrote:
> The qemu-img info --backing-chain option enumerates the backing file
> chain. For example, for base.qcow2 <- snap1.qcow2 <- snap2.qcow2 the
> output becomes:
>
> + do {
> + bs = bdrv_new_open(filename, fmt, BDRV_O_FLAGS | BDRV_O_NO_BACKING,
> + false);
> + if (!bs) {
> + goto err;
> + }
> + } while (filename);
Eww - infinite loop if presented with malicious data where someone has
used 'qemu-img rebase -u' to create a cycle. I think you need a
followup patch that hashes which files have been opened to date, and
abort the loop once a cycle is detected.
--
Eric Blake eblake@redhat.com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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next prev parent reply other threads:[~2012-10-12 14:24 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-12 14:09 [Qemu-devel] [PATCH] qemu-img: Add --backing-chain option to info command Stefan Hajnoczi
2012-10-12 14:18 ` Eric Blake
2012-10-12 14:24 ` Eric Blake [this message]
2012-10-12 14:27 ` Kevin Wolf
2012-10-12 14:32 ` Eric Blake
2012-10-12 14:38 ` Kevin Wolf
2012-10-12 14:50 ` Eric Blake
2012-10-12 19:16 ` Kashyap Chamarthy
2012-10-12 20:19 ` Kashyap Chamarthy
2012-10-12 20:31 ` Eric Blake
2012-10-13 15:50 ` Kashyap Chamarthy
2012-10-13 21:36 ` Eric Blake
2012-10-14 6:10 ` Kashyap Chamarthy
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