From: Budimir Markovic markovicbudimir@gmail.com
[ 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@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 [ v4.14: Delete NL_SET_ERR_MSG because extack is not added to hfsc_change_class ] Cc: stable@vger.kernel.org # 4.14 Signed-off-by: Shaoying Xu shaoyi@amazon.com --- net/sched/sch_hfsc.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/net/sched/sch_hfsc.c b/net/sched/sch_hfsc.c index 3f88b75488b0..3a43abe4d9c4 100644 --- a/net/sched/sch_hfsc.c +++ b/net/sched/sch_hfsc.c @@ -1020,6 +1020,8 @@ hfsc_change_class(struct Qdisc *sch, u32 classid, u32 parentid, if (parent == NULL) return -ENOENT; } + if (!(parent->cl_flags & HFSC_FSC) && parent != &q->root) + return -EINVAL;
if (classid == 0 || TC_H_MAJ(classid ^ sch->handle) != 0) return -EINVAL;