openvswitch: Fix double-free on ip_defrag() errors
If ip_defrag() returns an error other than -EINPROGRESS, then the skb is
freed. When handle_fragments() passes this back up to
do_execute_actions(), it will be freed again. Prevent this double free
by never freeing the skb in do_execute_actions() for errors returned by
ovs_ct_execute. Always free it in ovs_ct_execute() error paths instead.
Fixes: 7f8a436eaa2c ("openvswitch: Add conntrack action")
Reported-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Joe Stringer <joestringer@nicira.com>
Acked-by: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/openvswitch/conntrack.c b/net/openvswitch/conntrack.c
index a5ec34f..b5dcc0a 100644
--- a/net/openvswitch/conntrack.c
+++ b/net/openvswitch/conntrack.c
@@ -293,6 +293,9 @@
return helper->help(skb, protoff, ct, ctinfo);
}
+/* Returns 0 on success, -EINPROGRESS if 'skb' is stolen, or other nonzero
+ * value if 'skb' is freed.
+ */
static int handle_fragments(struct net *net, struct sw_flow_key *key,
u16 zone, struct sk_buff *skb)
{
@@ -308,8 +311,8 @@
return err;
ovs_cb.mru = IPCB(skb)->frag_max_size;
- } else if (key->eth.type == htons(ETH_P_IPV6)) {
#if IS_ENABLED(CONFIG_NF_DEFRAG_IPV6)
+ } else if (key->eth.type == htons(ETH_P_IPV6)) {
enum ip6_defrag_users user = IP6_DEFRAG_CONNTRACK_IN + zone;
struct sk_buff *reasm;
@@ -318,17 +321,18 @@
if (!reasm)
return -EINPROGRESS;
- if (skb == reasm)
+ if (skb == reasm) {
+ kfree_skb(skb);
return -EINVAL;
+ }
key->ip.proto = ipv6_hdr(reasm)->nexthdr;
skb_morph(skb, reasm);
consume_skb(reasm);
ovs_cb.mru = IP6CB(skb)->frag_max_size;
-#else
- return -EPFNOSUPPORT;
#endif
} else {
+ kfree_skb(skb);
return -EPFNOSUPPORT;
}
@@ -473,6 +477,9 @@
return false;
}
+/* Returns 0 on success, -EINPROGRESS if 'skb' is stolen, or other nonzero
+ * value if 'skb' is freed.
+ */
int ovs_ct_execute(struct net *net, struct sk_buff *skb,
struct sw_flow_key *key,
const struct ovs_conntrack_info *info)
@@ -508,6 +515,8 @@
&info->labels.mask);
err:
skb_push(skb, nh_ofs);
+ if (err)
+ kfree_skb(skb);
return err;
}