Commit 12186be7 authored Jun 02, 2009 by Minoru Usui Committed by David S. Miller Jun 02, 2009

net_cls: fix unconfigured struct tcf_proto keeps chaining and avoid kernel...


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>

parent ea30e119

net/sched/cls_api.c

+17 −6

Original line number	Diff line number	Diff line
		@@ -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 @@ replay:
		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 @@ replay:
		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 @@ replay:
		}

		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)

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