From: "Serge E. Hallyn" <serge@hallyn.com>
To: "Serge E. Hallyn" <serge@hallyn.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>,
Andy Lutomirski <luto@amacapital.net>,
Seth Forshee <seth.forshee@canonical.com>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Serge Hallyn <serge.hallyn@canonical.com>,
James Morris <james.l.morris@oracle.com>,
Linux FS Devel <linux-fsdevel@vger.kernel.org>,
LSM List <linux-security-module@vger.kernel.org>,
SELinux-NSA <selinux@tycho.nsa.gov>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 3/7] fs: Ignore file caps in mounts from other user namespaces
Date: Wed, 29 Jul 2015 11:18:06 -0500 [thread overview]
Message-ID: <20150729161806.GB21625@mail.hallyn.com> (raw)
In-Reply-To: <20150729160450.GA21625@mail.hallyn.com>
On Wed, Jul 29, 2015 at 11:04:50AM -0500, Serge E. Hallyn wrote:
> On Thu, Jul 16, 2015 at 12:04:43AM -0500, Eric W. Biederman wrote:
> > > I tend to thing that, if we're not honoring the fcaps, we shouldn't be
> > > honoring the setuid bit either. After all, it's really not a trusted
> > > file, even though the only user who could have messed with it really
> > > is the apparent owner.
> >
> > For the file caps we can't honor them because you don't have the bits
> > in struct cred.
> >
> > For setuid we can honor it, and setuid is something that the user
> > namespace allows.
>
> Setuid is something explicitly tied to the user id. File capabilities
> are MAC, that is, explicitly orthogonal to user id. So 100% agreed with
> honoring setuid in user_ns and, for now, ignoring file caps.
Hm. No. Seems like both should be fine when current is in the mounter's
user_ns, and ignored otherwise.
(The below is still needed :)
> As I've mentioned a few times privately, I'm intending to implement
> user-namespaced file capabilities as a new xattr. Design is not 100%
> nailed down, but probably it would support a set of userns_fcaps, each
> of which lists the k_uid of the root user in the namespace assigning the
> filecaps, followed by three sets. Then when exec()ing the file, if
> the current->userns->root user has a userns_fcap entry, or there is a -1
> entry, then use that, else use nothing. I think this is a very importing
> thing to support, to remove a barrier to shipping packages with software
> using filecaps. Without this, any package, say ping, which wants to
> support being installed in a (unprivileged) cotainer would need to also
> support use without filecaps, meaning that will likely be the only
> supported mode.
>
> -serge
WARNING: multiple messages have this Message-ID (diff)
From: "Serge E. Hallyn" <serge@hallyn.com>
To: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Serge Hallyn <serge.hallyn@canonical.com>,
SELinux-NSA <selinux@tycho.nsa.gov>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Andy Lutomirski <luto@amacapital.net>,
Seth Forshee <seth.forshee@canonical.com>,
LSM List <linux-security-module@vger.kernel.org>,
James Morris <james.l.morris@oracle.com>,
Linux FS Devel <linux-fsdevel@vger.kernel.org>,
Alexander Viro <viro@zeniv.linux.org.uk>
Subject: Re: [PATCH 3/7] fs: Ignore file caps in mounts from other user namespaces
Date: Wed, 29 Jul 2015 11:18:06 -0500 [thread overview]
Message-ID: <20150729161806.GB21625@mail.hallyn.com> (raw)
In-Reply-To: <20150729160450.GA21625@mail.hallyn.com>
On Wed, Jul 29, 2015 at 11:04:50AM -0500, Serge E. Hallyn wrote:
> On Thu, Jul 16, 2015 at 12:04:43AM -0500, Eric W. Biederman wrote:
> > > I tend to thing that, if we're not honoring the fcaps, we shouldn't be
> > > honoring the setuid bit either. After all, it's really not a trusted
> > > file, even though the only user who could have messed with it really
> > > is the apparent owner.
> >
> > For the file caps we can't honor them because you don't have the bits
> > in struct cred.
> >
> > For setuid we can honor it, and setuid is something that the user
> > namespace allows.
>
> Setuid is something explicitly tied to the user id. File capabilities
> are MAC, that is, explicitly orthogonal to user id. So 100% agreed with
> honoring setuid in user_ns and, for now, ignoring file caps.
Hm. No. Seems like both should be fine when current is in the mounter's
user_ns, and ignored otherwise.
(The below is still needed :)
> As I've mentioned a few times privately, I'm intending to implement
> user-namespaced file capabilities as a new xattr. Design is not 100%
> nailed down, but probably it would support a set of userns_fcaps, each
> of which lists the k_uid of the root user in the namespace assigning the
> filecaps, followed by three sets. Then when exec()ing the file, if
> the current->userns->root user has a userns_fcap entry, or there is a -1
> entry, then use that, else use nothing. I think this is a very importing
> thing to support, to remove a barrier to shipping packages with software
> using filecaps. Without this, any package, say ping, which wants to
> support being installed in a (unprivileged) cotainer would need to also
> support use without filecaps, meaning that will likely be the only
> supported mode.
>
> -serge
next prev parent reply other threads:[~2015-07-29 16:18 UTC|newest]
Thread overview: 210+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-15 19:46 [PATCH 0/7] Initial support for user namespace owned mounts Seth Forshee
2015-07-15 19:46 ` Seth Forshee
2015-07-15 19:46 ` [PATCH 1/7] fs: Add user namesapace member to struct super_block Seth Forshee
2015-07-15 19:46 ` Seth Forshee
2015-07-16 2:47 ` Eric W. Biederman
2015-07-16 2:47 ` Eric W. Biederman
2015-08-05 21:03 ` Seth Forshee
2015-08-05 21:03 ` Seth Forshee
2015-08-05 21:19 ` Eric W. Biederman
2015-08-05 21:19 ` Eric W. Biederman
2015-08-06 14:20 ` Seth Forshee
2015-08-06 14:20 ` Seth Forshee
2015-08-06 14:51 ` Stephen Smalley
2015-08-06 14:51 ` Stephen Smalley
2015-08-06 15:44 ` Seth Forshee
2015-08-06 15:44 ` Seth Forshee
2015-08-06 16:11 ` Stephen Smalley
2015-08-06 16:11 ` Stephen Smalley
2015-08-07 14:16 ` Seth Forshee
2015-08-07 14:16 ` Seth Forshee
2015-08-07 14:32 ` Seth Forshee
2015-08-07 14:32 ` Seth Forshee
2015-08-07 18:35 ` Casey Schaufler
2015-08-07 18:35 ` Casey Schaufler
2015-08-07 18:57 ` Seth Forshee
2015-08-07 18:57 ` Seth Forshee
2015-07-15 19:46 ` [PATCH 2/7] userns: Simpilify MNT_NODEV handling Seth Forshee
2015-07-15 19:46 ` Seth Forshee
2015-07-15 19:46 ` [PATCH 3/7] fs: Ignore file caps in mounts from other user namespaces Seth Forshee
2015-07-15 19:46 ` Seth Forshee
2015-07-15 21:48 ` Serge E. Hallyn
2015-07-15 21:48 ` Serge E. Hallyn
2015-07-15 21:50 ` Andy Lutomirski
2015-07-15 21:50 ` Andy Lutomirski
2015-07-15 22:35 ` Eric W. Biederman
2015-07-15 22:35 ` Eric W. Biederman
2015-07-16 1:14 ` Seth Forshee
2015-07-16 1:14 ` Seth Forshee
2015-07-16 1:23 ` Andy Lutomirski
2015-07-16 1:23 ` Andy Lutomirski
2015-07-16 13:06 ` Seth Forshee
2015-07-16 13:06 ` Seth Forshee
2015-07-16 1:19 ` Andy Lutomirski
2015-07-16 1:19 ` Andy Lutomirski
2015-07-16 4:23 ` Eric W. Biederman
2015-07-16 4:23 ` Eric W. Biederman
2015-07-16 4:49 ` Andy Lutomirski
2015-07-16 4:49 ` Andy Lutomirski
2015-07-16 5:04 ` Eric W. Biederman
2015-07-16 5:04 ` Eric W. Biederman
2015-07-16 5:15 ` Andy Lutomirski
2015-07-16 5:15 ` Andy Lutomirski
2015-07-16 5:44 ` Eric W. Biederman
2015-07-16 5:44 ` Eric W. Biederman
2015-07-16 13:13 ` Seth Forshee
2015-07-16 13:13 ` Seth Forshee
2015-07-17 0:43 ` Eric W. Biederman
2015-07-17 0:43 ` Eric W. Biederman
2015-07-29 16:04 ` Serge E. Hallyn
2015-07-29 16:04 ` Serge E. Hallyn
2015-07-29 16:18 ` Serge E. Hallyn [this message]
2015-07-29 16:18 ` Serge E. Hallyn
2015-07-15 19:46 ` [PATCH 4/7] fs: Treat foreign mounts as nosuid Seth Forshee
2015-07-15 19:46 ` Seth Forshee
2015-07-17 6:46 ` Nikolay Borisov
2015-07-17 6:46 ` Nikolay Borisov
2015-07-15 19:46 ` [PATCH 5/7] security: Restrict security attribute updates for userns mounts Seth Forshee
2015-07-15 19:46 ` Seth Forshee
2015-07-15 19:46 ` [PATCH 6/7] selinux: Ignore security labels on user namespace mounts Seth Forshee
2015-07-15 19:46 ` Seth Forshee
2015-07-16 13:23 ` Stephen Smalley
2015-07-22 16:02 ` Stephen Smalley
2015-07-22 16:14 ` Seth Forshee
2015-07-22 16:14 ` Seth Forshee
2015-07-22 20:25 ` Stephen Smalley
2015-07-22 20:25 ` Stephen Smalley
2015-07-22 20:40 ` Stephen Smalley
2015-07-22 20:40 ` Stephen Smalley
2015-07-23 13:57 ` Stephen Smalley
2015-07-23 13:57 ` Stephen Smalley
2015-07-23 14:39 ` Seth Forshee
2015-07-23 14:39 ` Seth Forshee
2015-07-23 15:36 ` Stephen Smalley
2015-07-23 15:36 ` Stephen Smalley
2015-07-23 16:23 ` Seth Forshee
2015-07-23 16:23 ` Seth Forshee
2015-07-24 15:11 ` Seth Forshee
2015-07-24 15:11 ` Seth Forshee
2015-07-30 15:57 ` Stephen Smalley
2015-07-30 15:57 ` Stephen Smalley
2015-07-30 16:24 ` Seth Forshee
2015-07-30 16:24 ` Seth Forshee
2015-07-15 19:46 ` [PATCH 7/7] smack: Don't use security labels for " Seth Forshee
2015-07-15 19:46 ` Seth Forshee
2015-07-15 20:43 ` Casey Schaufler
2015-07-15 20:43 ` Casey Schaufler
2015-07-15 20:36 ` [PATCH 0/7] Initial support for user namespace owned mounts Casey Schaufler
2015-07-15 20:36 ` Casey Schaufler
2015-07-15 21:06 ` Eric W. Biederman
2015-07-15 21:06 ` Eric W. Biederman
2015-07-15 21:48 ` Seth Forshee
2015-07-15 21:48 ` Seth Forshee
2015-07-15 22:28 ` Eric W. Biederman
2015-07-15 22:28 ` Eric W. Biederman
2015-07-16 1:05 ` Andy Lutomirski
2015-07-16 1:05 ` Andy Lutomirski
2015-07-16 2:20 ` Eric W. Biederman
2015-07-16 2:20 ` Eric W. Biederman
2015-07-16 13:12 ` Stephen Smalley
2015-07-16 13:12 ` Stephen Smalley
2015-07-15 23:04 ` Casey Schaufler
2015-07-15 23:04 ` Casey Schaufler
2015-07-15 22:39 ` Casey Schaufler
2015-07-15 22:39 ` Casey Schaufler
2015-07-16 1:08 ` Andy Lutomirski
2015-07-16 1:08 ` Andy Lutomirski
2015-07-16 2:54 ` Casey Schaufler
2015-07-16 2:54 ` Casey Schaufler
2015-07-16 4:47 ` Eric W. Biederman
2015-07-16 4:47 ` Eric W. Biederman
2015-07-17 0:09 ` Dave Chinner
2015-07-17 0:09 ` Dave Chinner
2015-07-17 0:42 ` Eric W. Biederman
2015-07-17 0:42 ` Eric W. Biederman
2015-07-17 2:47 ` Dave Chinner
2015-07-17 2:47 ` Dave Chinner
2015-07-21 17:37 ` J. Bruce Fields
2015-07-21 17:37 ` J. Bruce Fields
2015-07-22 7:56 ` Dave Chinner
2015-07-22 7:56 ` Dave Chinner
2015-07-22 14:09 ` J. Bruce Fields
2015-07-22 14:09 ` J. Bruce Fields
2015-07-22 16:52 ` Austin S Hemmelgarn
2015-07-22 16:52 ` Austin S Hemmelgarn
2015-07-22 17:41 ` J. Bruce Fields
2015-07-22 17:41 ` J. Bruce Fields
2015-07-23 1:51 ` Dave Chinner
2015-07-23 1:51 ` Dave Chinner
2015-07-23 13:19 ` J. Bruce Fields
2015-07-23 13:19 ` J. Bruce Fields
2015-07-23 23:48 ` Dave Chinner
2015-07-23 23:48 ` Dave Chinner
2015-07-18 0:07 ` Serge E. Hallyn
2015-07-18 0:07 ` Serge E. Hallyn
2015-07-20 17:54 ` Colin Walters
2015-07-20 17:54 ` Colin Walters
2015-07-16 11:16 ` Lukasz Pawelczyk
2015-07-16 11:16 ` Lukasz Pawelczyk
2015-07-17 0:10 ` Eric W. Biederman
2015-07-17 0:10 ` Eric W. Biederman
2015-07-17 10:13 ` Lukasz Pawelczyk
2015-07-17 10:13 ` Lukasz Pawelczyk
2015-07-16 3:15 ` Eric W. Biederman
2015-07-16 3:15 ` Eric W. Biederman
2015-07-16 13:59 ` Seth Forshee
2015-07-16 13:59 ` Seth Forshee
2015-07-16 15:09 ` Casey Schaufler
2015-07-16 15:09 ` Casey Schaufler
2015-07-16 18:57 ` Seth Forshee
2015-07-16 18:57 ` Seth Forshee
2015-07-16 21:42 ` Casey Schaufler
2015-07-16 21:42 ` Casey Schaufler
2015-07-16 22:27 ` Andy Lutomirski
2015-07-16 22:27 ` Andy Lutomirski
2015-07-16 23:08 ` Casey Schaufler
2015-07-16 23:08 ` Casey Schaufler
2015-07-16 23:29 ` Andy Lutomirski
2015-07-16 23:29 ` Andy Lutomirski
2015-07-17 0:45 ` Casey Schaufler
2015-07-17 0:45 ` Casey Schaufler
2015-07-17 0:59 ` Andy Lutomirski
2015-07-17 0:59 ` Andy Lutomirski
2015-07-17 14:28 ` Serge E. Hallyn
2015-07-17 14:28 ` Serge E. Hallyn
2015-07-17 14:56 ` Seth Forshee
2015-07-17 14:56 ` Seth Forshee
2015-07-21 20:35 ` Seth Forshee
2015-07-21 20:35 ` Seth Forshee
2015-07-22 1:52 ` Casey Schaufler
2015-07-22 1:52 ` Casey Schaufler
2015-07-22 15:56 ` Seth Forshee
2015-07-22 15:56 ` Seth Forshee
2015-07-22 18:10 ` Casey Schaufler
2015-07-22 18:10 ` Casey Schaufler
2015-07-22 19:32 ` Seth Forshee
2015-07-22 19:32 ` Seth Forshee
2015-07-23 0:05 ` Casey Schaufler
2015-07-23 0:05 ` Casey Schaufler
2015-07-23 0:15 ` Eric W. Biederman
2015-07-23 0:15 ` Eric W. Biederman
2015-07-23 5:15 ` Seth Forshee
2015-07-23 5:15 ` Seth Forshee
2015-07-23 21:48 ` Casey Schaufler
2015-07-23 21:48 ` Casey Schaufler
2015-07-28 20:40 ` Seth Forshee
2015-07-28 20:40 ` Seth Forshee
2015-07-30 16:18 ` Casey Schaufler
2015-07-30 16:18 ` Casey Schaufler
2015-07-30 17:05 ` Eric W. Biederman
2015-07-30 17:05 ` Eric W. Biederman
2015-07-30 17:25 ` Seth Forshee
2015-07-30 17:25 ` Seth Forshee
2015-07-30 17:33 ` Eric W. Biederman
2015-07-30 17:33 ` Eric W. Biederman
2015-07-17 13:21 ` Seth Forshee
2015-07-17 13:21 ` Seth Forshee
2015-07-17 17:14 ` Casey Schaufler
2015-07-17 17:14 ` Casey Schaufler
2015-07-16 15:59 ` Seth Forshee
2015-07-16 15:59 ` Seth Forshee
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