net_cls: fix unconfigured struct tcf_proto keeps chaining and avoid kernel panic when we use cls_cgroup
This patch fixes a bug which unconfigured struct tcf_proto keeps
chaining in tc_ctl_tfilter(), and avoids kernel panic in
cls_cgroup_classify() when we use cls_cgroup.
When we execute 'tc filter add', tcf_proto is allocated, initialized
by classifier's init(), and chained. After it's chained,
tc_ctl_tfilter() calls classifier's change(). When classifier's
change() fails, tc_ctl_tfilter() does not free and keeps tcf_proto.
In addition, cls_cgroup is initialized in change() not in init(). It
accesses unconfigured struct tcf_proto which is chained before
change(), then hits Oops.
Signed-off-by: Minoru Usui <usui@mxm.nes.nec.co.jp>
Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca>
Tested-by: Minoru Usui <usui@mxm.nes.nec.co.jp>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index 0759f32..09cdcdf 100644
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -135,6 +135,7 @@
unsigned long cl;
unsigned long fh;
int err;
+ int tp_created = 0;
if (net != &init_net)
return -EINVAL;
@@ -266,10 +267,7 @@
goto errout;
}
- spin_lock_bh(root_lock);
- tp->next = *back;
- *back = tp;
- spin_unlock_bh(root_lock);
+ tp_created = 1;
} else if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], tp->ops->kind))
goto errout;
@@ -296,8 +294,11 @@
switch (n->nlmsg_type) {
case RTM_NEWTFILTER:
err = -EEXIST;
- if (n->nlmsg_flags & NLM_F_EXCL)
+ if (n->nlmsg_flags & NLM_F_EXCL) {
+ if (tp_created)
+ tcf_destroy(tp);
goto errout;
+ }
break;
case RTM_DELTFILTER:
err = tp->ops->delete(tp, fh);
@@ -314,8 +315,18 @@
}
err = tp->ops->change(tp, cl, t->tcm_handle, tca, &fh);
- if (err == 0)
+ if (err == 0) {
+ if (tp_created) {
+ spin_lock_bh(root_lock);
+ tp->next = *back;
+ *back = tp;
+ spin_unlock_bh(root_lock);
+ }
tfilter_notify(skb, n, tp, fh, RTM_NEWTFILTER);
+ } else {
+ if (tp_created)
+ tcf_destroy(tp);
+ }
errout:
if (cl)
