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From: Stephen Smalley <sds@tycho.nsa.gov>
To: Daniel Colascione <dancol@google.com>,
	linux-api@vger.kernel.org, linux-kernel@vger.kernel.org,
	lokeshgidra@google.com, nnk@google.com
Cc: nosh@google.com, timmurray@google.com
Subject: Re: [PATCH 0/7] Harden userfaultfd
Date: Fri, 15 Nov 2019 10:09:20 -0500
Message-ID: <77f984c6-0da2-8e6f-e3f4-9dab2bfb6c79@tycho.nsa.gov> (raw)
In-Reply-To: <20191012191602.45649-1-dancol@google.com>

On 10/12/19 3:15 PM, Daniel Colascione wrote:
> Userfaultfd in unprivileged contexts could be potentially very
> useful. We'd like to harden userfaultfd to make such unprivileged use
> less risky. This patch series allows SELinux to manage userfaultfd
> file descriptors (via a new flag, for compatibility with existing
> code) and allows administrators to limit userfaultfd to servicing
> user-mode faults, increasing the difficulty of using userfaultfd in
> exploit chains invoking delaying kernel faults.
> 
> A new anon_inodes interface allows callers to opt into SELinux
> management of anonymous file objects. In this mode, anon_inodes
> creates new ephemeral inodes for anonymous file objects instead of
> reusing a singleton dummy inode. A new LSM hook gives security modules
> an opportunity to configure and veto these ephemeral inodes.
> 
> Existing anon_inodes users must opt into the new functionality.
> 
> Daniel Colascione (7):
>    Add a new flags-accepting interface for anonymous inodes
>    Add a concept of a "secure" anonymous file
>    Add a UFFD_SECURE flag to the userfaultfd API.
>    Teach SELinux about a new userfaultfd class
>    Let userfaultfd opt out of handling kernel-mode faults
>    Allow users to require UFFD_SECURE
>    Add a new sysctl for limiting userfaultfd to user mode faults
> 
>   Documentation/admin-guide/sysctl/vm.rst | 19 +++++-
>   fs/anon_inodes.c                        | 89 +++++++++++++++++--------
>   fs/userfaultfd.c                        | 47 +++++++++++--
>   include/linux/anon_inodes.h             | 27 ++++++--
>   include/linux/lsm_hooks.h               |  8 +++
>   include/linux/security.h                |  2 +
>   include/linux/userfaultfd_k.h           |  3 +
>   include/uapi/linux/userfaultfd.h        | 14 ++++
>   kernel/sysctl.c                         |  9 +++
>   security/security.c                     |  8 +++
>   security/selinux/hooks.c                | 68 +++++++++++++++++++
>   security/selinux/include/classmap.h     |  2 +
>   12 files changed, 256 insertions(+), 40 deletions(-)

Please, in the future, cc selinux@vger.kernel.org for patches that 
modify SELinux.



      parent reply index

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-12 19:15 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
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 [this message]

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