From: James Bottomley <James.Bottomley@HansenPartnership.com>
To: Matthew Garrett <mjg59@google.com>
Cc: Mimi Zohar <zohar@linux.ibm.com>,
linux-integrity <linux-integrity@vger.kernel.org>,
Dmitry Kasatkin <dmitry.kasatkin@gmail.com>,
linux-fsdevel@vger.kernel.org, miklos@szeredi.hu
Subject: Re: [PATCH V2 3/4] IMA: Optionally make use of filesystem-provided hashes
Date: Thu, 04 Apr 2019 15:35:15 -0700 [thread overview]
Message-ID: <1554417315.24612.15.camel@HansenPartnership.com> (raw)
In-Reply-To: <CACdnJutZzJu7FxcLWasyvx9BLQJeGrA=7WA389JL8ixFJ6Skrg@mail.gmail.com>
On Thu, 2019-04-04 at 15:26 -0700, Matthew Garrett wrote:
> On Thu, Apr 4, 2019 at 3:18 PM James Bottomley
> <James.Bottomley@hansenpartnership.com> wrote:
> > The obvious other thought is integration with fs-verity, which is a
> > filesystem maintained possibly signed merkel tree hash. The
> > problem here is what does vfs_get_hash() actually mean? The
> > assumption seems to be that it is the flat hash of the entire file
> > which doesn't work for merkle trees. However, if it could be a
> > representative hash of the file which is produced however the
> > filesystem decides, it could work (well, unless the file is copied
> > on to a different fs, of course ...).
>
> We could always use fs-verity to store additional verifiable metadata
> including actual hashes for consistency?
Redundant information is always possible, but it can become
inconsistent and, because the hashes can't be derived from each other,
it's hard to tell if it is inconsistent without redoing the whole hash
with each method.
I was more wondering what, if any, problems would follow if we did let
the filesystem choose the hash method and simply used the top merkle
hash in place of the usual IMA hash?
James
next prev parent reply other threads:[~2019-04-04 22:35 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-26 21:50 Allow trusted filesystems to provide IMA hashes directly Matthew Garrett
2019-02-26 21:50 ` [PATCH V2 1/4] VFS: Add a call to obtain a file's hash Matthew Garrett
2019-02-26 21:50 ` [PATCH V2 2/4] IMA: Allow rule matching on filesystem subtype Matthew Garrett
2019-02-26 21:50 ` [PATCH V2 3/4] IMA: Optionally make use of filesystem-provided hashes Matthew Garrett
2019-02-28 16:03 ` Mimi Zohar
2019-02-28 18:05 ` Mimi Zohar
2019-02-28 21:41 ` Matthew Garrett
2019-02-28 21:59 ` Mimi Zohar
2019-02-28 22:38 ` Matthew Garrett
2019-03-04 19:52 ` Matthew Garrett
2019-03-04 20:32 ` Mimi Zohar
2019-03-04 22:10 ` Matthew Garrett
2019-03-05 13:18 ` Mimi Zohar
2019-03-05 18:39 ` Matthew Garrett
2019-03-05 19:51 ` Mimi Zohar
2019-03-05 20:27 ` Matthew Garrett
2019-03-06 12:30 ` Mimi Zohar
2019-03-06 18:31 ` Matthew Garrett
2019-03-06 22:38 ` Mimi Zohar
2019-03-06 23:36 ` Matthew Garrett
2019-03-07 1:54 ` Mimi Zohar
2019-03-07 4:19 ` Matthew Garrett
2019-03-07 20:48 ` Mimi Zohar
2019-03-07 22:41 ` Matthew Garrett
2019-04-04 21:46 ` Matthew Garrett
2019-04-04 22:18 ` James Bottomley
2019-04-04 22:26 ` Matthew Garrett
2019-04-04 22:35 ` James Bottomley [this message]
2019-04-05 1:50 ` Matthew Garrett
2019-04-05 2:26 ` James Bottomley
2019-04-05 20:55 ` Matthew Garrett
2019-04-29 22:51 ` Matthew Garrett
2019-05-02 20:25 ` Mimi Zohar
2019-05-02 22:37 ` Matthew Garrett
2019-05-02 23:02 ` Mimi Zohar
2019-05-03 6:51 ` Roberto Sassu
2019-05-03 8:17 ` Roberto Sassu
2019-05-03 12:47 ` Mimi Zohar
2019-05-03 13:20 ` Roberto Sassu
2019-02-26 21:50 ` [PATCH V2 4/4] FUSE: Allow filesystems to provide gethash methods Matthew Garrett
2019-02-27 14:26 ` Jann Horn
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