diff options
authorGao Feng <>2017-06-28 12:53:54 +0800
committerDavid S. Miller <>2017-06-29 12:55:12 -0400
commitc1a4872ebfb83b1af7144f7b29ac8c4b344a12a8 (patch)
parent713a98d90c5ea072c1bb00ef40617aee2cef2232 (diff)
net: sched: Fix one possible panic when no destroy callback
When qdisc fail to init, qdisc_create would invoke the destroy callback to cleanup. But there is no check if the callback exists really. So it would cause the panic if there is no real destroy callback like the qdisc codel, fq, and so on. Take codel as an example following: When a malicious user constructs one invalid netlink msg, it would cause codel_init->codel_change->nla_parse_nested failed. Then kernel would invoke the destroy callback directly but qdisc codel doesn't define one. It causes one panic as a result. Now add one the check for destroy to avoid the possible panic. Fixes: 87b60cfacf9f ("net_sched: fix error recovery at qdisc creation") Signed-off-by: Gao Feng <> Acked-by: Eric Dumazet <> Signed-off-by: David S. Miller <>
1 files changed, 2 insertions, 1 deletions
diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index e88342fde1bc..cfdbfa18a95e 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -1019,7 +1019,8 @@ static struct Qdisc *qdisc_create(struct net_device *dev,
return sch;
/* ops->init() failed, we call ->destroy() like qdisc_create_dflt() */
- ops->destroy(sch);
+ if (ops->destroy)
+ ops->destroy(sch);
kfree((char *) sch - sch->padded);