Commit 9918b511 authored Feb 03, 2015 by Ignacy Gawędzki Committed by Greg Kroah-Hartman Oct 27, 2017

cls_api.c: Fix dumping of non-existing actions' stats.

commit b057df24a7536cce6c372efe9d0e3d1558afedf4 upstream.

In tcf_exts_dump_stats(), ensure that exts->actions is not empty before
accessing the first element of that list and calling tcf_action_copy_stats()
on it. This fixes some random segvs when adding filters of type "basic" with
no particular action.

This also fixes the dumping of those "no-action" filters, which more often
than not made calls to tcf_action_copy_stats() fail and consequently netlink
attributes added by the caller to be removed by a call to nla_nest_cancel().

Fixes: 33be6271 ("net_sched: act: use standard struct list_head")
Signed-off-by: Ignacy Gawędzki <ignacy.gawedzki@green-communications.fr>
Acked-by: Cong Wang <cwang@twopensource.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Cc: J Pommnitz <jpo234@outlook.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 98c4e5ca

net/sched/cls_api.c

+4 −3

Original line number	Diff line number	Diff line
		@@ -564,7 +564,8 @@ void tcf_exts_change(struct tcf_proto tp, struct tcf_exts dst,
		EXPORT_SYMBOL(tcf_exts_change);

		#define tcf_exts_first_act(ext) \
		list_first_entry(&(exts)->actions, struct tc_action, list)
		list_first_entry_or_null(&(exts)->actions, \
		struct tc_action, list)

		int tcf_exts_dump(struct sk_buff skb, struct tcf_exts exts)
		{
		@@ -610,7 +611,7 @@ int tcf_exts_dump_stats(struct sk_buff skb, struct tcf_exts exts)
		{
		#ifdef CONFIG_NET_CLS_ACT
		struct tc_action *a = tcf_exts_first_act(exts);
		if (tcf_action_copy_stats(skb, a, 1) < 0)
		if (a != NULL && tcf_action_copy_stats(skb, a, 1) < 0)
		return -1;
		#endif
		return 0;