net/sched: sch_hfsc: Ensure inner classes have fsc curve
[ Upstream commit b3d26c5702c7d6c45456326e56d2ccf3f103e60f ]
HFSC assumes that inner classes have an fsc curve, but it is currently
possible for classes without an fsc curve to become parents. This leads
to bugs including a use-after-free.
Don't allow non-root classes without HFSC_FSC to become parents.
BUG=b/300062914
TEST=None
RELEASE_NOTE=Fixed CVE-2023-4623 in the linux kernel.
cos-patch: security-high
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-by: Budimir Markovic <markovicbudimir@gmail.com>
Signed-off-by: Budimir Markovic <markovicbudimir@gmail.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Link: https://lore.kernel.org/r/20230824084905.422-1-markovicbudimir@gmail.com
Change-Id: Ie5cb6ce6ca451825c460587c46a577ab7fe3e9ee
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Reviewed-on: https://cos-review.googlesource.com/c/third_party/kernel/+/57328
Reviewed-by: Oleksandr Tymoshenko <ovt@google.com>
Tested-by: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
Main-Branch-Verified: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
diff --git a/net/sched/sch_hfsc.c b/net/sched/sch_hfsc.c
index 70b0c58..61d5259 100644
--- a/net/sched/sch_hfsc.c
+++ b/net/sched/sch_hfsc.c
@@ -1012,6 +1012,10 @@
if (parent == NULL)
return -ENOENT;
}
+ if (!(parent->cl_flags & HFSC_FSC) && parent != &q->root) {
+ NL_SET_ERR_MSG(extack, "Invalid parent - parent class must have FSC");
+ return -EINVAL;
+ }
if (classid == 0 || TC_H_MAJ(classid ^ sch->handle) != 0)
return -EINVAL;
