Commit b057df24 authored by Ignacy Gawędzki's avatar Ignacy Gawędzki Committed by David S. Miller

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

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: default avatarIgnacy Gawędzki <ignacy.gawedzki@green-communications.fr>
Acked-by: default avatarCong Wang <cwang@twopensource.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 3725a269
......@@ -556,8 +556,9 @@ 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)
#define tcf_exts_first_act(ext) \
list_first_entry_or_null(&(exts)->actions, \
struct tc_action, list)
int tcf_exts_dump(struct sk_buff *skb, struct tcf_exts *exts)
{
......@@ -603,7 +604,7 @@ 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;
......
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