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net_cls: fix unconfigured struct tcf_proto keeps chaining and avoid kernel panic when we use cls_cgroup

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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>
This commit is contained in:
Minoru Usui 2009-06-02 02:17:34 -07:00 committed by David S. Miller
parent ea30e11970
commit 12186be7d2
1 changed files with 17 additions and 6 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

23
net/sched/cls_api.c
View file

@ -135,6 +135,7 @@ static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n, void *arg)
unsigned long cl;
unsigned long fh;
int err;
int tp_created = 0;
if (net != &init_net)
return -EINVAL;
@ -266,10 +267,7 @@ static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n, void *arg)
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 @@ static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n, void *arg)
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 @@ static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n, void *arg)
}
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)