From: Mimi Zohar <zohar@linux.vnet.ibm.com>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Dave Chinner <david@fromorbit.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
LSM List <linux-security-module@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Christoph Hellwig <hch@infradead.org>,
"Theodore Ts'o" <tytso@mit.edu>, Jan Kara <jack@suse.cz>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-integrity@vger.kernel.org,
Sascha Hauer <s.hauer@pengutronix.de>
Subject: Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been taken exclusively
Date: Mon, 02 Oct 2017 08:25:09 -0400 [thread overview]
Message-ID: <1506947109.5691.282.camel@linux.vnet.ibm.com> (raw)
In-Reply-To: <87zi9ai63l.fsf@xmission.com>
On Sun, 2017-10-01 at 22:25 -0500, Eric W. Biederman wrote:
> Mimi Zohar <zohar@linux.vnet.ibm.com> writes:
> > There should be no open writers in ima_check_last_writer(), so the
> > file shouldn't be changing.
>
> This is slightly tangential but I think important to consider.
> What do you do about distributed filesystems fuse, nfs, etc that
> can change the data behind the kernels back.
Exactly!
> Do you not support such systems or do you have a sufficient way to
> detect changes?
Currently, only the initial file access in policy is measured,
verified, audited. Even if there was a way of detecting the change,
since we can't trust these file systems, the performance would be
awful, but we should probably not be caching the
measurement/verification results.
Mimi
WARNING: multiple messages have this Message-ID (diff)
From: zohar@linux.vnet.ibm.com (Mimi Zohar)
To: linux-security-module@vger.kernel.org
Subject: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been taken exclusively
Date: Mon, 02 Oct 2017 08:25:09 -0400 [thread overview]
Message-ID: <1506947109.5691.282.camel@linux.vnet.ibm.com> (raw)
In-Reply-To: <87zi9ai63l.fsf@xmission.com>
On Sun, 2017-10-01 at 22:25 -0500, Eric W. Biederman wrote:
> Mimi Zohar <zohar@linux.vnet.ibm.com> writes:
> > There should be no open writers in ima_check_last_writer(), so the
> > file shouldn't be changing.
>
> This is slightly tangential but I think important to consider.
> What do you do about distributed filesystems fuse, nfs, etc that
> can change the data behind the kernels back.
Exactly!
> Do you not support such systems or do you have a sufficient way to
> detect changes?
Currently, only the initial file access in policy is measured,
verified, audited. ?Even if there was a way of detecting the change,
since we can't trust these file systems, the performance would be
awful, but we should probably not be caching the
measurement/verification results.
Mimi
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WARNING: multiple messages have this Message-ID (diff)
From: Mimi Zohar <zohar@linux.vnet.ibm.com>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Dave Chinner <david@fromorbit.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
LSM List <linux-security-module@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Christoph Hellwig <hch@infradead.org>,
"Theodore Ts'o" <tytso@mit.edu>, Jan Kara <jack@suse.cz>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-integrity@vger.kernel.org,
Sascha Hauer <s.hauer@pengutronix.de>
Subject: Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been taken exclusively
Date: Mon, 02 Oct 2017 08:25:09 -0400 [thread overview]
Message-ID: <1506947109.5691.282.camel@linux.vnet.ibm.com> (raw)
In-Reply-To: <87zi9ai63l.fsf@xmission.com>
On Sun, 2017-10-01 at 22:25 -0500, Eric W. Biederman wrote:
> Mimi Zohar <zohar@linux.vnet.ibm.com> writes:
> > There should be no open writers in ima_check_last_writer(), so the
> > file shouldn't be changing.
>
> This is slightly tangential but I think important to consider.
> What do you do about distributed filesystems fuse, nfs, etc that
> can change the data behind the kernels back.
Exactly!
> Do you not support such systems or do you have a sufficient way to
> detect changes?
Currently, only the initial file access in policy is measured,
verified, audited. Even if there was a way of detecting the change,
since we can't trust these file systems, the performance would be
awful, but we should probably not be caching the
measurement/verification results.
Mimi
next prev parent reply other threads:[~2017-10-02 12:25 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-28 12:39 [RFC PATCH 0/3] define new read_iter file operation rwf flag Mimi Zohar
2017-09-28 12:39 ` Mimi Zohar
2017-09-28 12:39 ` [RFC PATCH 1/3] fs: define new read_iter " Mimi Zohar
2017-09-28 12:39 ` Mimi Zohar
2017-09-28 13:54 ` Matthew Wilcox
2017-09-28 13:54 ` Matthew Wilcox
2017-09-28 14:33 ` Mimi Zohar
2017-09-28 14:33 ` Mimi Zohar
2017-09-28 15:51 ` Linus Torvalds
2017-09-28 15:51 ` Linus Torvalds
2017-09-28 12:39 ` [RFC PATCH 2/3] integrity: use call_read_iter to calculate the file hash Mimi Zohar
2017-09-28 12:39 ` Mimi Zohar
2017-09-28 12:39 ` [RFC PATCH 3/3] fs: detect that the i_rwsem has already been taken exclusively Mimi Zohar
2017-09-28 12:39 ` Mimi Zohar
2017-09-28 22:02 ` Dave Chinner
2017-09-28 22:02 ` Dave Chinner
2017-09-28 23:39 ` Linus Torvalds
2017-09-28 23:39 ` Linus Torvalds
2017-09-29 0:12 ` Mimi Zohar
2017-09-29 0:12 ` Mimi Zohar
2017-09-29 0:12 ` Mimi Zohar
2017-09-29 0:33 ` Linus Torvalds
2017-09-29 0:33 ` Linus Torvalds
2017-09-29 1:53 ` Mimi Zohar
2017-09-29 1:53 ` Mimi Zohar
2017-09-29 1:53 ` Mimi Zohar
2017-09-29 3:26 ` Linus Torvalds
2017-09-29 3:26 ` Linus Torvalds
2017-10-01 1:33 ` Eric W. Biederman
2017-10-01 1:33 ` Eric W. Biederman
[not found] ` <CA+55aFx726wT4VprN-sHm6s8Q_PV_VjhTBC4goEbMcerYU1Tig@mail.gmail.com>
2017-10-01 12:08 ` Mimi Zohar
2017-10-01 12:08 ` Mimi Zohar
2017-10-01 12:08 ` Mimi Zohar
2017-10-01 18:41 ` Linus Torvalds
2017-10-01 18:41 ` Linus Torvalds
2017-10-01 22:34 ` Dave Chinner
2017-10-01 22:34 ` Dave Chinner
2017-10-01 23:15 ` Linus Torvalds
2017-10-01 23:15 ` Linus Torvalds
2017-10-02 3:54 ` Dave Chinner
2017-10-02 3:54 ` Dave Chinner
2017-10-01 23:42 ` Mimi Zohar
2017-10-01 23:42 ` Mimi Zohar
2017-10-01 23:42 ` Mimi Zohar
2017-10-02 3:25 ` Eric W. Biederman
2017-10-02 3:25 ` Eric W. Biederman
2017-10-02 3:25 ` Eric W. Biederman
2017-10-02 12:25 ` Mimi Zohar [this message]
2017-10-02 12:25 ` Mimi Zohar
2017-10-02 12:25 ` Mimi Zohar
2017-10-02 4:35 ` Dave Chinner
2017-10-02 4:35 ` Dave Chinner
2017-10-02 4:35 ` Dave Chinner
2017-10-02 4:35 ` Dave Chinner
2017-10-02 12:09 ` Mimi Zohar
2017-10-02 12:09 ` Mimi Zohar
2017-10-02 12:09 ` Mimi Zohar
2017-10-02 12:43 ` Jeff Layton
2017-10-02 12:43 ` Jeff Layton
2017-10-01 22:06 ` Eric W. Biederman
2017-10-01 22:06 ` Eric W. Biederman
2017-10-01 22:20 ` Linus Torvalds
2017-10-01 22:20 ` Linus Torvalds
2017-10-01 23:54 ` Mimi Zohar
2017-10-01 23:54 ` Mimi Zohar
2017-10-01 23:54 ` Mimi Zohar
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