From b3d26c5702c7d6c45456326e56d2ccf3f103e60f Mon Sep 17 00:00:00 2001
From: Budimir Markovic <markovicbudimir@gmail.com>
Date: Thu, 24 Aug 2023 01:49:05 -0700
Subject: [PATCH] net/sched: sch_hfsc: Ensure inner classes have fsc curve
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@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
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
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 70b0c5873d326..61d52594ff6d8 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;
--
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