netdev - [PATCH net v2] cls_api.c: Fix dumping of non-existing actions' stats.

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20150203180518.GA3806@zenon.in.qult.net>
Date:	Tue, 3 Feb 2015 19:05:18 +0100
From:	Ignacy Gawędzki 
	<ignacy.gawedzki@...en-communications.fr>
To:	netdev@...r.kernel.org
Subject: [PATCH net v2] 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: 33be62715991 ("net_sched: act: use standard struct list_head")
Signed-off-by: Ignacy Gawędzki <ignacy.gawedzki@...en-communications.fr>
---
 net/sched/cls_api.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index aad6a67..baef987 100644
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -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;
-- 
2.1.0
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html