tree aeeb880fea8d52f7e5e1bcebe2aaf9c3ad5b7a8e
parent 6947a95cc7172abca5cceca3ed9454da47dd1407
author Pedro Tammela <pctammela@mojatatu.com> 1675953459 -0300
committer Robert Kolchmeyer <rkolchmeyer@google.com> 1678494579 +0000

net/sched: tcindex: update imperfect hash filters respecting rcu

commit ee059170b1f7e94e55fa6cadee544e176a6e59c2 upstream.

The imperfect hash area can be updated while packets are traversing,
which will cause a use-after-free when 'tcf_exts_exec()' is called
with the destroyed tcf_ext.

CPU 0:               CPU 1:
tcindex_set_parms    tcindex_classify
tcindex_lookup
                     tcindex_lookup
tcf_exts_change
                     tcf_exts_exec [UAF]

Stop operating on the shared area directly, by using a local copy,
and update the filter with 'rcu_replace_pointer()'. Delete the old
filter version only after a rcu grace period elapsed.

Fixes: 9b0d4446b569 ("net: sched: avoid atomic swap in tcf_exts_change")
Reported-by: valis <sec@valis.email>
Suggested-by: valis <sec@valis.email>
Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Pedro Tammela <pctammela@mojatatu.com>
Link: https://lore.kernel.org/r/20230209143739.279867-1-pctammela@mojatatu.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit becf55394f6acb60dd60634a1c797e73c747f9da)
Signed-off-by: Robert Kolchmeyer <rkolchmeyer@google.com>

BUG=b/272275066
TEST=presubmit
RELEASE_NOTE=Fixed a use-after-free issue in net/sched in the Linux kernel.

cos-patch: bug
Change-Id: I90db125604863e762c398882d92a4807dd3ee6b1
Reviewed-on: https://cos-review.googlesource.com/c/third_party/kernel/+/44712
Tested-by: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
Reviewed-by: Oleksandr Tymoshenko <ovt@google.com>