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From: David Howells <dhowells@redhat.com>
To: Jann Horn <jannh@google.com>, casey@schaufler-ca.com
Cc: dhowells@redhat.com, Al Viro <viro@zeniv.linux.org.uk>,
	raven@themaw.net, linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	Linux API <linux-api@vger.kernel.org>,
	linux-block@vger.kernel.org, keyrings@vger.kernel.org,
	linux-security-module <linux-security-module@vger.kernel.org>,
	kernel list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 3/7] vfs: Add a mount-notification facility
Date: Wed, 29 May 2019 12:00:57 +0100	[thread overview]
Message-ID: <14347.1559127657@warthog.procyon.org.uk> (raw)
In-Reply-To: <CAG48ez2rRh2_Kq_EGJs5k-ZBNffGs_Q=vkQdinorBgo58tbGpg@mail.gmail.com>

Jann Horn <jannh@google.com> wrote:

> > +void post_mount_notification(struct mount *changed,
> > +                            struct mount_notification *notify)
> > +{
> > +       const struct cred *cred = current_cred();
> 
> This current_cred() looks bogus to me. Can't mount topology changes
> come from all sorts of places? For example, umount_mnt() from
> umount_tree() from dissolve_on_fput() from __fput(), which could
> happen pretty much anywhere depending on where the last reference gets
> dropped?

IIRC, that's what Casey argued is the right thing to do from a security PoV.
Casey?

Maybe I should pass in NULL creds in the case that an event is being generated
because an object is being destroyed due to the last usage[*] being removed.

 [*] Usage, not ref - Superblocks are a bit weird in their accounting.

David

  parent reply	other threads:[~2019-05-29 11:01 UTC|newest]

Thread overview: 65+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-28 16:01 [RFC][PATCH 0/7] Mount, FS, Block and Keyrings notifications David Howells
2019-05-28 16:01 ` [PATCH 1/7] General notification queue with user mmap()'able ring buffer David Howells
2019-05-28 16:26   ` Greg KH
2019-05-28 17:30   ` David Howells
2019-05-28 23:12     ` Greg KH
2019-05-29 16:06     ` David Howells
2019-05-29 17:46       ` Jann Horn
2019-05-29 21:02       ` David Howells
2019-05-31 11:14         ` Peter Zijlstra
2019-05-31 12:02         ` David Howells
2019-05-31 13:26           ` Peter Zijlstra
2019-05-31 14:20           ` David Howells
2019-05-31 16:44             ` Peter Zijlstra
2019-05-31 17:12             ` David Howells
2019-06-17 16:24               ` Peter Zijlstra
2019-05-29 23:09       ` Greg KH
2019-05-29 23:11       ` Greg KH
2019-05-30  9:50         ` Andrea Parri
2019-05-31  8:35           ` Peter Zijlstra
2019-05-31  8:47       ` Peter Zijlstra
2019-05-31 12:42       ` David Howells
2019-05-31 14:55       ` David Howells
2019-05-28 19:14   ` Jann Horn
2019-05-28 22:28   ` David Howells
2019-05-28 23:16     ` Jann Horn
2019-05-28 16:02 ` [PATCH 2/7] keys: Add a notification facility David Howells
2019-05-28 16:02 ` [PATCH 3/7] vfs: Add a mount-notification facility David Howells
2019-05-28 20:06   ` Jann Horn
2019-05-28 23:04   ` David Howells
2019-05-28 23:23     ` Jann Horn
2019-05-29 11:16     ` David Howells
2019-05-28 23:08   ` David Howells
2019-05-29 10:55   ` David Howells
2019-05-29 11:00   ` David Howells [this message]
2019-05-29 15:53     ` Casey Schaufler
2019-05-29 16:12       ` Jann Horn
2019-05-29 17:04         ` Casey Schaufler
2019-06-03 16:30         ` David Howells
2019-05-29 17:13       ` Andy Lutomirski
2019-05-29 17:46         ` Casey Schaufler
2019-05-29 18:11           ` Jann Horn
2019-05-29 19:28             ` Casey Schaufler
2019-05-29 19:47               ` Jann Horn
2019-05-29 20:50                 ` Casey Schaufler
2019-05-29 23:12           ` Andy Lutomirski
2019-05-29 23:56             ` Casey Schaufler
2019-05-28 16:02 ` [PATCH 4/7] vfs: Add superblock notifications David Howells
2019-05-28 20:27   ` Jann Horn
2019-05-29 12:58   ` David Howells
2019-05-29 14:16     ` Jann Horn
2019-05-28 16:02 ` [PATCH 5/7] fsinfo: Export superblock notification counter David Howells
2019-05-28 16:02 ` [PATCH 6/7] block: Add block layer notifications David Howells
2019-05-28 20:37   ` Jann Horn
2019-05-28 16:02 ` [PATCH 7/7] Add sample notification program David Howells
2019-05-28 23:58 ` [RFC][PATCH 0/7] Mount, FS, Block and Keyrings notifications Greg KH
2019-05-29  6:33 ` Amir Goldstein
2019-05-29 14:25   ` Jan Kara
2019-05-29 15:10     ` Greg KH
2019-05-29 15:53     ` Amir Goldstein
2019-05-30 11:00       ` Jan Kara
2019-06-04 12:33     ` David Howells
2019-05-29  6:45 ` David Howells
2019-05-29  7:40   ` Amir Goldstein
2019-05-29  9:09 ` David Howells
2019-05-29 15:41   ` Casey Schaufler

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