[PATCH v2 0/6] Harden userfaultfd

[Stephen Smalley]

On 2/11/20 6:27 PM, Daniel Colascione wrote:
> On Tue, Feb 11, 2020 at 3:13 PM Casey Schaufler <casey at schaufler-ca.com> wrote:
>>
>> On 2/11/2020 2:55 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 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 (6):
>>>    Add a new flags-accepting interface for anonymous inodes
>>>    Add a concept of a "secure" anonymous file
>>>    Teach SELinux about a new userfaultfd class
>>>    Wire UFFD up to SELinux
>>>    Let userfaultfd opt out of handling kernel-mode faults
>>>    Add a new sysctl for limiting userfaultfd to user mode faults
>>
>> This must be posted to the linux Security Module list
>> <linux-security-module at vger.kernel.org>
> 
> Added. I thought selinux@ was sufficient.

scripts/get_maintainer.pl can be helpful in identifying relevant lists 
and maintainers for each patch.  I don't use its output blindly as it 
tends to over-approximate but since your patches span the VFS, LSM 
framework, and selinux, you do need to include relevant 
maintainers/lists for each.