From: Paul Moore <paul@paul-moore.com>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: Christian Brauner <brauner@kernel.org>,
Miklos Szeredi <mszeredi@redhat.com>,
Matthew House <mattlloydhouse@gmail.com>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-api@vger.kernel.org, linux-man@vger.kernel.org,
linux-security-module@vger.kernel.org,
Karel Zak <kzak@redhat.com>, Ian Kent <raven@themaw.net>,
David Howells <dhowells@redhat.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Al Viro <viro@zeniv.linux.org.uk>,
Christian Brauner <christian@brauner.io>,
Amir Goldstein <amir73il@gmail.com>
Subject: Re: [RFC PATCH 3/3] add listmnt(2) syscall
Date: Wed, 4 Oct 2023 15:22:54 -0400 [thread overview]
Message-ID: <CAHC9VhQvpGUVzv=6M9f4NNn_qi+kjHPMVoppmSitHs6HVgZDOg@mail.gmail.com> (raw)
In-Reply-To: <CAJfpegtJwcS9=7dCAVCEoBwD_U2MX44a6B62iDsc78AZt6nM7Q@mail.gmail.com>
On Thu, Sep 28, 2023 at 6:07 AM Miklos Szeredi <miklos@szeredi.hu> wrote:
> On Tue, 19 Sept 2023 at 18:48, Paul Moore <paul@paul-moore.com> wrote:
>
> > > Ideally we avoid multiple capable(CAP_SYS_ADMIN) calls by only doing it
> > > once and saving the return value. capable() call's aren't that cheap.
> >
> > Agreed. The capability check doesn't do any subject/object
> > comparisons so calling it for each mount is overkill. However, I
> > would think we would want the LSM hook called from inside the loop as
> > that could involve a subject (@current) and object (individual mount
> > point) comparison.
My apologies, I was traveling and while I was quickly checking my
email each day this message was lost. I'm very sorry for the delay in
responding.
> The security_sb_statfs() one?
Yes.
> Should a single failure result in a complete failure?
My opinion is that it should only result in the failure of that
listing/stat'ing that particular mount; if other mounts are allowed to
be queried than the operation should be allowed to continue.
> Why is it not enough to check permission on the parent?
Each mount has the potential to have a unique security identify in the
context of the LSM, and since the LSM access controls are generally
intended to support a subject-verb-object access control policy we
need to examine the subject and object together (the subject here is
@current, the object is the individual mount, and the verb is the
stat/list operation).
Does that make sense?
I'm looking at the v3 patchset right now, I've got some small nits,
but I'll add those to that thread.
--
paul-moore.com
next prev parent reply other threads:[~2023-10-04 19:23 UTC|newest]
Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-13 15:22 [RFC PATCH 0/3] quering mount attributes Miklos Szeredi
2023-09-13 15:22 ` [RFC PATCH 1/3] add unique mount ID Miklos Szeredi
2023-09-14 9:03 ` Christian Brauner
2023-09-14 9:30 ` Miklos Szeredi
2023-09-14 9:36 ` Christian Brauner
2023-09-14 9:43 ` Miklos Szeredi
2023-09-14 10:06 ` Christian Brauner
2023-09-15 1:31 ` Ian Kent
2023-09-13 15:22 ` [RFC PATCH 2/3] add statmnt(2) syscall Miklos Szeredi
2023-09-14 6:11 ` Amir Goldstein
2023-09-15 1:05 ` Ian Kent
2023-09-14 9:27 ` Christian Brauner
2023-09-14 10:13 ` Miklos Szeredi
2023-09-14 15:26 ` Christian Brauner
2023-09-15 8:56 ` Miklos Szeredi
2023-09-18 13:51 ` Christian Brauner
2023-09-18 14:14 ` Miklos Szeredi
2023-09-18 14:24 ` Christian Brauner
2023-09-18 14:32 ` Miklos Szeredi
2023-09-18 14:40 ` Christian Brauner
2023-09-18 14:51 ` Miklos Szeredi
2023-09-18 15:22 ` Christian Brauner
2023-09-18 15:39 ` Miklos Szeredi
2023-09-19 0:37 ` Matthew House
2023-09-19 8:02 ` Miklos Szeredi
2023-09-19 9:07 ` Christian Brauner
2023-09-19 10:51 ` Miklos Szeredi
2023-09-19 12:41 ` Christian Brauner
2023-09-19 12:59 ` Miklos Szeredi
2023-09-19 13:18 ` Christian Brauner
2023-09-19 21:28 ` Matthew House
2023-09-20 9:42 ` Miklos Szeredi
2023-09-20 13:26 ` Matthew House
2023-09-21 7:34 ` Miklos Szeredi
2023-09-26 13:48 ` Florian Weimer
2023-09-26 14:06 ` Miklos Szeredi
2023-09-26 14:19 ` Florian Weimer
2023-09-26 14:33 ` Miklos Szeredi
2023-09-26 14:39 ` Florian Weimer
2023-09-26 14:36 ` Christian Brauner
2023-09-26 14:13 ` Christian Brauner
2023-09-18 20:58 ` Andreas Dilger
2023-09-19 12:50 ` Christian Brauner
2023-09-20 0:33 ` Dave Chinner
2023-09-18 14:29 ` Jeff Layton
2023-09-18 14:35 ` Christian Brauner
2023-09-20 9:43 ` David Laight
2023-09-14 20:39 ` Paul Moore
2023-09-15 9:10 ` Miklos Szeredi
2023-09-17 18:18 ` Sargun Dhillon
2023-09-17 23:36 ` Ian Kent
2023-09-18 13:05 ` Christian Brauner
2023-09-25 12:57 ` Arnd Bergmann
2023-09-25 13:04 ` Christian Brauner
2023-09-25 13:13 ` Miklos Szeredi
2023-09-25 13:19 ` Christian Brauner
2023-09-25 13:20 ` Miklos Szeredi
2023-09-25 15:46 ` Arnd Bergmann
2023-09-26 10:05 ` Christian Brauner
2023-09-27 8:46 ` Miklos Szeredi
2023-09-13 15:22 ` [RFC PATCH 3/3] add listmnt(2) syscall Miklos Szeredi
2023-09-14 6:00 ` Amir Goldstein
2023-09-14 8:50 ` Miklos Szeredi
2023-09-14 10:01 ` Christian Brauner
2023-09-15 1:00 ` Ian Kent
2023-09-17 0:54 ` Matthew House
2023-09-17 14:32 ` Miklos Szeredi
2023-09-18 13:15 ` Christian Brauner
2023-09-19 16:47 ` Paul Moore
2023-09-28 10:07 ` Miklos Szeredi
2023-10-04 19:22 ` Paul Moore [this message]
2023-09-14 6:47 ` [RFC PATCH 0/3] quering mount attributes Amir Goldstein
2023-09-15 1:20 ` Ian Kent
2023-09-15 3:06 ` Amir Goldstein
2023-09-16 2:04 ` Ian Kent
2023-09-16 2:19 ` Ian Kent
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