On Sat, Feb 12, 2022 at 6:59 PM Ondrej Mosnacek [off-list ref] wrote:

This is a third round of patches to fix the SCTP-SELinux interaction
w.r.t. client-side peeloff. The patches are a modified version of Xin
Long's patches posted previously, of which only a part was merged (the
rest was merged for a while, but was later reverted):
https://lore.kernel.org/selinux/cover.1635854268.git.lucien.xin@gmail.com/T/ (local)

In gist, these patches replace the call to
security_inet_conn_established() in SCTP with a new hook
security_sctp_assoc_established() and implement the new hook in SELinux
so that the client-side association labels are set correctly (which
matters in case the association eventually gets peeled off into a
separate socket).

Note that other LSMs than SELinux don't implement the SCTP hooks nor
inet_conn_established, so they shouldn't be affected by any of these
changes.

These patches were tested by selinux-testsuite [1] with an additional
patch [2] and by lksctp-tools func_tests [3].

Changes since v2:
- patches 1 and 2 dropped as they are already in mainline (not reverted)
- in patch 3, the return value of security_sctp_assoc_established() is
  changed to int, the call is moved earlier in the function, and if the
  hook returns an error value, the packet will now be discarded,
  aborting the association
- patch 4 has been changed a lot - please see the patch description for
  details on how the hook is now implemented and why

[1] https://github.com/SELinuxProject/selinux-testsuite/
[2] https://patchwork.kernel.org/project/selinux/patch/20211021144543.740762-1-omosnace@redhat.com/

Actually, that patch no longer applies to the current master. Please
refer to this rebased version instead:
https://patchwork.kernel.org/project/selinux/patch/20220212213454.689886-1-omosnace@redhat.com/

[3] https://github.com/sctp/lksctp-tools/tree/master/src/func_tests

Ondrej Mosnacek (2):
  security: add sctp_assoc_established hook
  security: implement sctp_assoc_established hook in selinux

 Documentation/security/SCTP.rst | 22 ++++----
 include/linux/lsm_hook_defs.h   |  2 +
 include/linux/lsm_hooks.h       |  5 ++
 include/linux/security.h        |  8 +++
 net/sctp/sm_statefuns.c         |  8 +--
 security/security.c             |  7 +++
 security/selinux/hooks.c        | 90 ++++++++++++++++++++++++---------
 7 files changed, 103 insertions(+), 39 deletions(-)

--
2.34.1

-- 
Ondrej Mosnacek
Software Engineer, Linux Security - SELinux kernel
Red Hat, Inc.