5.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Budimir Markovic <markovicbudimir@xxxxxxxxx>
[ 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.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-by: Budimir Markovic <markovicbudimir@xxxxxxxxx>
Signed-off-by: Budimir Markovic <markovicbudimir@xxxxxxxxx>
Acked-by: Jamal Hadi Salim <jhs@xxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20230824084905.422-1-markovicbudimir@xxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
net/sched/sch_hfsc.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/net/sched/sch_hfsc.c b/net/sched/sch_hfsc.c
index 92ad4115e473c..2af4adb7e84e4 100644
--- a/net/sched/sch_hfsc.c
+++ b/net/sched/sch_hfsc.c
@@ -1012,6 +1012,10 @@ hfsc_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
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;
--
2.40.1
