Add SELinux SCTP protocol support

Posting on behalf of Richard Haines. Patchset is based on selinux-tree/next. Some small conflicts are expected when merging with current net-next due to I-Data patches, including one at include/uapi/linux/sctp.h, on which the fix is to update the define SCTP_SENDMSG_CONNECT to a higher number.
Below is the original cover letter from Richard, and the changes from v2->v3.

The kernel patches have been built on Fedora 27 with kernel 4.13.12 plus the following userspace patches to enable testing:

1) Updates to libsepol 2.7 to support the sctp portcon statement. The patch is available from:
http://arctic.selinuxproject.org/~rhaines/selinux-sctp/
selinux-Add-support-for-the-SCTP-portcon-keyword.patch

2) Updates to the SELinux Test Suite adding SCTP tests. Please read the selinux-testsuite/README.sctp for details. The patch is available from:
http://arctic.selinuxproject.org/~rhaines/selinux-sctp/
selinux-testsuite-Add-SCTP-test-support.patch

3) Updates to lksctp-tools that show SELinux info in sctp_darn and sctp_test. It also contains a minor patch for test_1_to_1_connect.c as when CIPSO/CALIPSO configured, NetLabel returns a different error code for illegal addresses in test 5. The patch is available from:
http://arctic.selinuxproject.org/~rhaines/selinux-sctp/
lksctp-tools-Add-SELinux-support-to-sctp_test-and-sc.patch

All SCTP lksctp-tools/src/func_tests run correctly in enforcing mode.

All SCTP regression tests "./sctp-tests run" run correctly in enforcing mode. These tests are obtained from: https://github.com/sctp/sctp-tests

The selinux-testsuite patch also adds remote tests (that need some manual configuration). These are useful for testing CIPSO/CALIPSO over a network with a number of categories to produce large ip option fields with various message sizes forcing fragmentation etc..

Changes since RFC Patch:
Removed the NetLabel patch (was [RFC PATCH 4/5] netlabel: Add SCTP support) as re-engineered. However this patchset will require the NetLabel patch at [1] to fully run the SCTP selinux-testsuite.

PATCH 1/4
Remove unused parameter from security_sctp_assoc_request(). Reformat and update LSM-sctp.rst documentation.
PATCH 2/4
Add variables and RCU locks as requested in [2] to support IP options. PATCH 3/4
Added security_sctp_assoc_request() hook to sctp_sf_do_unexpected_init() and sctp_sf_do_5_2_4_dupcook().
Removed security_sctp_assoc_request() hook from sctp_sf_do_5_1C_ack() as no longer required.
PATCH 4/4
Reformat and update SELinux-sctp.rst documentation.
Remove bindx and connectx permissions.
Rework selinux_socket_connect() and selinux_netlbl_socket_connect() to utilise helpers for code reuse.
Add spinlock to selinux_sctp_assoc_request().
Remove unused parameter from security_sctp_assoc_request(). Use address->sa_family = AF_INET in *_bind and *_connect to ensure correct address type.
Minor cleanups.

Changes since v2 post by Richard:
Updated sctp_frag_point() to also consider the ip options len.

[1] https://marc.info/?l=selinux&m1061619115945&w=2
[2] https://marc.info/?l=selinux&m0962470215797&w=2

Richard Haines (4):
security: Add support for SCTP security hooks
sctp: Add ip option support
sctp: Add LSM hooks
selinux: Add SCTP support

 Documentation/security/LSM-sctp.rst     | 194 ++++++++++++++++++++++
 Documentation/security/SELinux-sctp.rst | 104 ++++++++++++
 include/linux/lsm_hooks.h               |  35 ++++
 include/linux/security.h                |  25 +++
 include/net/sctp/sctp.h                 |   4 +-
 include/net/sctp/structs.h              |  12 ++
 include/uapi/linux/sctp.h               |   1 +
 net/sctp/chunk.c                        |  13 +-
 net/sctp/ipv6.c                         |  42 ++++-
 net/sctp/output.c                       |   5 +-
 net/sctp/protocol.c                     |  36 +++++
 net/sctp/sm_make_chunk.c                |  12 ++
 net/sctp/sm_statefuns.c                 |  18 +++
 net/sctp/socket.c                       |  70 +++++++-
 security/security.c                     |  22 +++
 security/selinux/hooks.c                | 278 +++++++++++++++++++++++++++++---
 security/selinux/include/classmap.h     |   2 +-
 security/selinux/include/netlabel.h     |  15 +-
 security/selinux/include/objsec.h       |   4 +
 security/selinux/netlabel.c             | 128 +++++++++++++--
 20 files changed, 971 insertions(+), 49 deletions(-)
 create mode 100644 Documentation/security/LSM-sctp.rst
 create mode 100644 Documentation/security/SELinux-sctp.rst

2.14.3