From: Andy Lutomirski <luto@kernel.org>
To: Daniel Colascione <dancol@google.com>
Cc: Andy Lutomirski <luto@kernel.org>,
Linux API <linux-api@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Lokesh Gidra <lokeshgidra@google.com>,
Nick Kralevich <nnk@google.com>, Nosh Minwalla <nosh@google.com>,
Tim Murray <timmurray@google.com>
Subject: Re: [PATCH 4/7] Teach SELinux about a new userfaultfd class
Date: Sat, 12 Oct 2019 17:46:16 -0700 [thread overview]
Message-ID: <CALCETrWFFbgdR3qtsQhxdMbaocoeHHkwpTQ-mQKJ4mgWBHz-Ng@mail.gmail.com> (raw)
In-Reply-To: <CAKOZuevQD-xsy_PrvT7F3Pqaoo5apZFukj2ZKLLQKup1cwgZ-A@mail.gmail.com>
On Sat, Oct 12, 2019 at 5:12 PM Daniel Colascione <dancol@google.com> wrote:
>
> On Sat, Oct 12, 2019 at 4:09 PM Andy Lutomirski <luto@kernel.org> wrote:
> >
> > On Sat, Oct 12, 2019 at 12:16 PM Daniel Colascione <dancol@google.com> wrote:
> > >
> > > Use the secure anonymous inode LSM hook we just added to let SELinux
> > > policy place restrictions on userfaultfd use. The create operation
> > > applies to processes creating new instances of these file objects;
> > > transfer between processes is covered by restrictions on read, write,
> > > and ioctl access already checked inside selinux_file_receive.
> >
> > This is great, and I suspect we'll want it for things like SGX, too.
> > But the current design seems like it will make it essentially
> > impossible for SELinux to reference an anon_inode class whose
> > file_operations are in a module, and moving file_operations out of a
> > module would be nasty.
> >
> > Could this instead be keyed off a new struct anon_inode_class, an
> > enum, or even just a string?
>
> The new LSM hook already receives the string that callers pass to the
> anon_inode APIs; modules can look at that instead of the fops if they
> want. The reason to pass both the name and the fops through the hook
> is to allow LSMs to match using fops comparison (which seems less
> prone to breakage) when possible and rely on string matching when it
> isn't.
I suppose that whoever makes the first module that wants to use this
mechanism can have the fun task of reworking it. There's nothing
user-visible here that would make it hard to change in the future.
next prev parent reply other threads:[~2019-10-13 0:46 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-12 19:15 [PATCH 0/7] Harden userfaultfd Daniel Colascione
2019-10-12 19:15 ` [PATCH 1/7] Add a new flags-accepting interface for anonymous inodes Daniel Colascione
2019-10-14 4:26 ` kbuild test robot
2019-10-14 15:38 ` Jann Horn
2019-10-14 18:15 ` Daniel Colascione
2019-10-14 18:30 ` Jann Horn
2019-10-15 8:08 ` Christoph Hellwig
2019-10-12 19:15 ` [PATCH 2/7] Add a concept of a "secure" anonymous file Daniel Colascione
2019-10-14 3:01 ` kbuild test robot
2019-10-15 8:08 ` Christoph Hellwig
2019-10-12 19:15 ` [PATCH 3/7] Add a UFFD_SECURE flag to the userfaultfd API Daniel Colascione
2019-10-12 23:10 ` Andy Lutomirski
2019-10-13 0:51 ` Daniel Colascione
2019-10-13 1:14 ` Andy Lutomirski
2019-10-13 1:38 ` Daniel Colascione
2019-10-14 16:04 ` Jann Horn
2019-10-23 19:09 ` Andrea Arcangeli
2019-10-23 19:21 ` Andy Lutomirski
2019-10-23 21:16 ` Andrea Arcangeli
2019-10-23 21:25 ` Andy Lutomirski
2019-10-23 22:41 ` Andrea Arcangeli
2019-10-23 23:01 ` Andy Lutomirski
2019-10-23 23:27 ` Andrea Arcangeli
2019-10-23 20:05 ` Daniel Colascione
2019-10-24 0:23 ` Andrea Arcangeli
2019-10-23 20:15 ` Linus Torvalds
2019-10-24 9:02 ` Mike Rapoport
2019-10-24 15:10 ` Andrea Arcangeli
2019-10-25 20:12 ` Mike Rapoport
2019-10-22 21:27 ` Daniel Colascione
2019-10-23 4:11 ` Andy Lutomirski
2019-10-23 7:29 ` Cyrill Gorcunov
2019-10-23 12:43 ` Mike Rapoport
2019-10-23 17:13 ` Andy Lutomirski
2019-10-12 19:15 ` [PATCH 4/7] Teach SELinux about a new userfaultfd class Daniel Colascione
2019-10-12 23:08 ` Andy Lutomirski
2019-10-13 0:11 ` Daniel Colascione
2019-10-13 0:46 ` Andy Lutomirski [this message]
2019-10-12 19:16 ` [PATCH 5/7] Let userfaultfd opt out of handling kernel-mode faults Daniel Colascione
2019-10-12 19:16 ` [PATCH 6/7] Allow users to require UFFD_SECURE Daniel Colascione
2019-10-12 23:12 ` Andy Lutomirski
2019-10-12 19:16 ` [PATCH 7/7] Add a new sysctl for limiting userfaultfd to user mode faults Daniel Colascione
2019-10-16 0:02 ` [PATCH 0/7] Harden userfaultfd James Morris
2019-11-15 15:09 ` Stephen Smalley
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