linux/net/sctp
Ondrej Mosnacek 3a0504d54b sctp: fix association labeling in the duplicate COOKIE-ECHO case
sctp_sf_do_5_2_4_dupcook() currently calls security_sctp_assoc_request()
on new_asoc, but as it turns out, this association is always discarded
and the LSM labels never get into the final association (asoc).

This can be reproduced by having two SCTP endpoints try to initiate an
association with each other at approximately the same time and then peel
off the association into a new socket, which exposes the unitialized
labels and triggers SELinux denials.

Fix it by calling security_sctp_assoc_request() on asoc instead of
new_asoc. Xin Long also suggested limit calling the hook only to cases
A, B, and D, since in cases C and E the COOKIE ECHO chunk is discarded
and the association doesn't enter the ESTABLISHED state, so rectify that
as well.

One related caveat with SELinux and peer labeling: When an SCTP
connection is set up simultaneously in this way, we will end up with an
association that is initialized with security_sctp_assoc_request() on
both sides, so the MLS component of the security context of the
association will get swapped between the peers, instead of just one side
setting it to the other's MLS component. However, at that point
security_sctp_assoc_request() had already been called on both sides in
sctp_sf_do_unexpected_init() (on a temporary association) and thus if
the exchange didn't fail before due to MLS, it won't fail now either
(most likely both endpoints have the same MLS range).

Tested by:
 - reproducer from https://src.fedoraproject.org/tests/selinux/pull-request/530
 - selinux-testsuite (https://github.com/SELinuxProject/selinux-testsuite/)
 - sctp-tests (https://github.com/sctp/sctp-tests) - no tests failed
   that wouldn't fail also without the patch applied

Fixes: c081d53f97 ("security: pass asoc to sctp_assoc_request and sctp_sk_clone")
Suggested-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Acked-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Paul Moore <paul@paul-moore.com> (LSM/SELinux)
Link: https://patch.msgid.link/20240826130711.141271-1-omosnace@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-08-27 16:07:12 -07:00
..
associola.c sctp: update transport state when processing a dupcook packet 2023-10-04 17:29:44 -07:00
auth.c sctp: delete the nested flexible array hmac 2023-04-21 08:19:30 +01:00
bind_addr.c sctp: fail if no bound addresses can be used for a given scope 2023-01-24 18:32:33 -08:00
chunk.c net: sctp: chunk.c: delete duplicated word 2020-08-24 16:21:43 -07:00
debug.c sctp: add the probe timer in transport for PLPMTUD 2021-06-22 11:28:52 -07:00
diag.c inet_diag: add module pointer to "struct inet_diag_handler" 2024-01-23 15:13:54 +01:00
endpointola.c sctp: add dif and sdif check in asoc and ep lookup 2022-11-18 11:42:54 +00:00
input.c sctp: Fix null-ptr-deref in reuseport_add_sock(). 2024-08-02 16:25:06 -07:00
inqueue.c net: sctp: fix skb leak in sctp_inq_free() 2024-02-15 07:34:52 -08:00
ipv6.c ipv6: introduce dst_rt6_info() helper 2024-04-29 13:32:01 +01:00
Kconfig sctp: create udp4 sock and add its encap_rcv 2020-10-30 15:23:52 -07:00
Makefile sctp: add fair capacity stream scheduler 2023-03-09 11:31:44 +01:00
objcnt.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 104 2019-05-24 17:39:00 +02:00
offload.c net: move gso declarations and functions to their own files 2023-06-10 00:11:41 -07:00
output.c net: allow gso_max_size to exceed 65536 2022-05-16 10:18:55 +01:00
outqueue.c sctp: delete the nested flexible array variable 2023-04-21 08:19:29 +01:00
primitive.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 104 2019-05-24 17:39:00 +02:00
proc.c sctp: annotate data-races around sk->sk_wmem_queued 2023-08-31 11:56:59 +02:00
protocol.c inet: introduce dst_rtable() helper 2024-04-30 18:32:38 -07:00
sm_make_chunk.c sctp: Spelling s/preceeding/preceding/g 2023-10-04 14:04:58 -07:00
sm_sideeffect.c sctp: handle invalid error codes without calling BUG() 2023-06-12 09:36:27 +01:00
sm_statefuns.c sctp: fix association labeling in the duplicate COOKIE-ECHO case 2024-08-27 16:07:12 -07:00
sm_statetable.c sctp: add the probe timer in transport for PLPMTUD 2021-06-22 11:28:52 -07:00
socket.c sctp: cancel a blocking accept when shutdown a listen socket 2024-07-03 09:45:39 +01:00
stream_interleave.c sctp: delete the nested flexible array skip 2023-04-21 08:19:29 +01:00
stream_sched_fc.c sctp: add weighted fair queueing stream scheduler 2023-03-09 11:31:44 +01:00
stream_sched_prio.c sctp: add a refcnt in sctp_stream_priorities to avoid a nested loop 2023-02-23 12:59:40 -08:00
stream_sched_rr.c sctp: delete free member from struct sctp_sched_ops 2022-12-01 20:14:23 -08:00
stream_sched.c sctp: fix a potential OOB access in sctp_sched_set_sched() 2023-05-10 12:10:15 +01:00
stream.c sctp: delete the nested flexible array params 2023-04-21 08:19:29 +01:00
sysctl.c sysctl: treewide: constify the ctl_table argument of proc_handlers 2024-07-24 20:59:29 +02:00
transport.c sctp: fix an issue that plpmtu can never go to complete state 2023-05-22 11:05:20 +01:00
tsnmap.c net: sctp: trivial: fix typo in comment 2021-03-04 13:48:32 -08:00
ulpevent.c net: remove noblock parameter from recvmsg() entities 2022-04-12 15:00:25 +02:00
ulpqueue.c sctp: remove unnecessary NULL check in sctp_ulpq_tail_event() 2022-10-20 21:43:10 -07:00