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Date: Sun, 9 Sep 2018 02:31:22 +0100
From: Al Viro <viro@...IV.linux.org.uk>
To: netdev@...r.kernel.org
Cc: Jamal Hadi Salim <jhs@...atatu.com>,
Cong Wang <xiyou.wangcong@...il.com>,
Jiri Pirko <jiri@...nulli.us>
Subject: [PATCH net 03/13] net: sched: cls_u32: disallow linking to root hnode
From: Al Viro <viro@...iv.linux.org.uk>
Operation makes no sense. Nothing will actually break if we do so
(depth limit in u32_classify() will prevent infinite loops), but
according to maintainers it's best prohibited outright.
NOTE: doing so guarantees that u32_destroy() will trigger the call
of u32_destroy_hnode(); we might want to make that unconditional.
Test:
tc qdisc add dev eth0 ingress
tc filter add dev eth0 parent ffff: protocol ip prio 100 u32 \
link 800: offset at 0 mask 0f00 shift 6 plus 0 eat match ip protocol 6 ff
should fail with
Error: cls_u32: Not linking to root node
Signed-off-by: Al Viro <viro@...iv.linux.org.uk>
---
net/sched/cls_u32.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/net/sched/cls_u32.c b/net/sched/cls_u32.c
index c4782aa808c7..72459b09d910 100644
--- a/net/sched/cls_u32.c
+++ b/net/sched/cls_u32.c
@@ -797,6 +797,10 @@ static int u32_set_parms(struct net *net, struct tcf_proto *tp,
NL_SET_ERR_MSG_MOD(extack, "Link hash table not found");
return -EINVAL;
}
+ if (ht_down->is_root) {
+ NL_SET_ERR_MSG_MOD(extack, "Not linking to root node");
+ return -EINVAL;
+ }
ht_down->refcnt++;
}
--
2.11.0
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