Re: [PATCH v3 0/3] proc,security,selinux: let SELinux block FOLL_FORCE for /proc/self/mem

On Thu, Sep 10, 2026 at 3:48 AM Christian Brauner [off-list ref] wrote:

On Mon, 07 Sep 2026 23:00:15 +0200, Jann Horn wrote:

quoted

proc,security,selinux: let SELinux block FOLL_FORCE for /proc/self/mem

The goal of this series is to let SELinux prevent the use of FOLL_FORCE
when a process writes into /proc/self/mem and the system is configured
with PROC_MEM_FORCE_ALWAYS (which used to be the default behavior, and
is still used by current Android devices).

[...]

Let's move this on a shared branch that both the vfs tree and the lsm
tree pull. That's the standard way of handling dependencies between two
subsystems that want to route code that touches both of them. Branch is
stable.

For some reason (/me looks at gmail) your email never hit my inbox, I
only noticed it now while reviewing Jann's patchset.

Christian, can you explain why you merged LSM code that I haven't
ACK'd?  We've talked about this in the past and I think I've been
fairly clear about it; I wouldn't merge VFS code without an
ACK/Reviewed-by/etc. from you or Al, I've been expecting the same
consideration from you.

While I don't have a problem with a topic branch for this, can you
also explain why this topic branch should live in the VFS tree?  There
are more changes under security/ than fs/, and unless I've misread
Jann's cover letter, this entire patchset is focused around enabling
LSM/SELinux controls and not necessarily anything really new from a
VFS perspective.

---

Applied to the vfs-7.4.shared.lsm.foll_force branch of the vfs/vfs.git tree.
Patches in the vfs-7.4.shared.lsm.foll_force branch should appear in linux-next soon.

Please report any outstanding bugs that were missed during review in a
new review to the original patch series allowing us to drop it.

It's encouraged to provide Acked-bys and Reviewed-bys even though the
patch has now been applied. If possible patch trailers will be updated.

Note that commit hashes shown below are subject to change due to rebase,
trailer updates or similar. If in doubt, please check the listed branch.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git
branch: vfs-7.4.shared.lsm.foll_force

[1/3] proc: refactor /proc/$pid/mem to use struct as private_data
      https://git.kernel.org/vfs/vfs/c/d5662602d178
[2/3] proc: query LSMs for introspective mem access (if PROC_MEM_FORCE_ALWAYS)
      https://git.kernel.org/vfs/vfs/c/9f90f96af73d
[3/3] selinux: require PROCESS__PTRACE for FOLL_FORCE introspection
      https://git.kernel.org/vfs/vfs/c/5dac8c291d9b

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