From: Mikhail Kurinnoi <viewizard@viewizard.com>
To: Matthew Garrett <mjg59@google.com>
Cc: linux-integrity <linux-integrity@vger.kernel.org>,
Mimi Zohar <zohar@linux.vnet.ibm.com>,
Dmitry Kasatkin <dmitry.kasatkin@huawei.com>
Subject: Re: [RFC] EVM: Add support for portable signature format
Date: Thu, 26 Oct 2017 12:46:16 +0300 [thread overview]
Message-ID: <20171026124616.2f2ef1d2@totoro> (raw)
In-Reply-To: <CACdnJuvQUGXJb664ZVJk6Z_YDYomgRSwX_C3vk4DRk5EVj02Gg@mail.gmail.com>
? Thu, 26 Oct 2017 02:08:25 -0700
Matthew Garrett <mjg59@google.com> ?????:
> On Thu, Oct 26, 2017 at 2:03 AM, Mikhail Kurinnoi
> <viewizard@viewizard.com> wrote:
> > ? Thu, 26 Oct 2017 01:31:44 -0700
> > Matthew Garrett <mjg59@google.com> ?????:
> >
> >> @@ -317,7 +319,7 @@ void ima_update_xattr(struct
> >> integrity_iint_cache *iint, struct file *file) int rc = 0;
> >>
> >> /* do not collect and update hash for digital signatures */
> >> - if (iint->flags & IMA_DIGSIG)
> >> + if (iint->flags & IMA_DIGSIG || iint->flags &
> >> EVM_IMMUTABLE_DIGSIG) return;
> >>
> >
> > Isn't this mean, we already changed files data, and we just don't
> > allow IMA xattr update? This file will not pass integrity
> > verification next time.
>
> That's fine - policy may not care. It's easier to sign all files and
> then leave enforcement up to the local policy than it is to determine
> in advance which files will need protection.
>
> > I thought, the idea was prevent data changes, and in this way
> > prevent IMA xattr update.
>
> No, the goal is to be able to detect when files have been modified and
> (optionally) restrict access as a result. Otherwise the packaging
> system has to be able to identify all files that may be legitimately
> modified, which is something that may differ depending on the client.
> It's much easier to permit the data modification and have the local
> policy block reading or execution if it's actually a sensitive file.
Hmm...
http://www.spinics.net/lists/linux-integrity/msg00151.html
probably, we should decide first, what exactly immutable EVM mean.
It's hard to propose something or test patch if we still have
misunderstanding in concept of immutable EVM.
--
Best regards,
Mikhail Kurinnoi
next prev parent reply other threads:[~2017-10-26 9:46 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-26 8:31 [RFC] EVM: Add support for portable signature format Matthew Garrett
2017-10-26 9:03 ` Mikhail Kurinnoi
2017-10-26 9:08 ` Matthew Garrett
2017-10-26 9:46 ` Mikhail Kurinnoi [this message]
2017-10-26 19:22 ` Mimi Zohar
2017-10-30 10:53 ` Matthew Garrett
2017-10-30 11:36 ` Mimi Zohar
2017-10-30 11:51 ` Matthew Garrett
2017-10-30 12:14 ` Mimi Zohar
2017-10-27 10:27 ` Dmitry Kasatkin
2017-10-30 12:30 ` Mimi Zohar
2017-10-30 13:21 ` Matthew Garrett
2017-10-30 13:58 ` Mimi Zohar
2017-10-30 14:04 ` Matthew Garrett
2017-10-27 10:41 ` Dmitry Kasatkin
2017-10-30 12:38 ` Mimi Zohar
2017-10-30 13:17 ` Matthew Garrett
2017-10-30 15:31 ` Mimi Zohar
2017-10-30 15:36 ` Matthew Garrett
2017-11-01 17:54 ` Matthew Garrett
2017-11-01 18:25 ` Mimi Zohar
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