netdev - [PATCH net 1/4 v3] ipvlan: fix addr hash list corruption

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Date:	Sat, 28 Mar 2015 19:13:22 +0100
From:	Jiri Benc <jbenc@...hat.com>
To:	netdev@...r.kernel.org
Cc:	Mahesh Bandewar <maheshb@...gle.com>,
	Dan Williams <dcbw@...hat.com>
Subject: [PATCH net 1/4 v3] ipvlan: fix addr hash list corruption

When ipvlan interface with IP addresses attached is brought down and then
deleted, the assigned addresses are deleted twice from the address hash
list, first on the interface down and second on the link deletion.
Similarly, when an address is added while the interface is down, it is added
second time once the interface is brought up.

When the interface is down, the addresses should be kept off the hash list
for performance reasons. Ensure this is true, which also fixes the double add
problem. To fix the double free, check whether the address is hashed before
removing it.

Reported-by: Dan Williams <dcbw@...hat.com>
Signed-off-by: Jiri Benc <jbenc@...hat.com>
---

v2 -> v3: check hlist_unhashed also on addition; fixed comment coding style

v1 -> v2: check hlist_unhashed on deletion instead of depending on
netif_running
---
 drivers/net/ipvlan/ipvlan_core.c |  5 +++--
 drivers/net/ipvlan/ipvlan_main.c | 12 ++++++++++--
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ipvlan/ipvlan_core.c b/drivers/net/ipvlan/ipvlan_core.c
index 2a175006028b..8a542b9340c4 100644
--- a/drivers/net/ipvlan/ipvlan_core.c
+++ b/drivers/net/ipvlan/ipvlan_core.c
@@ -81,12 +81,13 @@ void ipvlan_ht_addr_add(struct ipvl_dev *ipvlan, struct ipvl_addr *addr)
 	hash = (addr->atype == IPVL_IPV6) ?
 	       ipvlan_get_v6_hash(&addr->ip6addr) :
 	       ipvlan_get_v4_hash(&addr->ip4addr);
-	hlist_add_head_rcu(&addr->hlnode, &port->hlhead[hash]);
+	if (hlist_unhashed(&addr->hlnode))
+		hlist_add_head_rcu(&addr->hlnode, &port->hlhead[hash]);
 }
 
 void ipvlan_ht_addr_del(struct ipvl_addr *addr, bool sync)
 {
-	hlist_del_rcu(&addr->hlnode);
+	hlist_del_init_rcu(&addr->hlnode);
 	if (sync)
 		synchronize_rcu();
 }
diff --git a/drivers/net/ipvlan/ipvlan_main.c b/drivers/net/ipvlan/ipvlan_main.c
index 4f4099d5603d..1eb3f33e11cc 100644
--- a/drivers/net/ipvlan/ipvlan_main.c
+++ b/drivers/net/ipvlan/ipvlan_main.c
@@ -622,7 +622,11 @@ static int ipvlan_add_addr6(struct ipvl_dev *ipvlan, struct in6_addr *ip6_addr)
 	addr->atype = IPVL_IPV6;
 	list_add_tail_rcu(&addr->anode, &ipvlan->addrs);
 	ipvlan->ipv6cnt++;
-	ipvlan_ht_addr_add(ipvlan, addr);
+	/* If the interface is not up, the address will be added to the hash
+	 * list by ipvlan_open.
+	 */
+	if (netif_running(ipvlan->dev))
+		ipvlan_ht_addr_add(ipvlan, addr);
 
 	return 0;
 }
@@ -690,7 +694,11 @@ static int ipvlan_add_addr4(struct ipvl_dev *ipvlan, struct in_addr *ip4_addr)
 	addr->atype = IPVL_IPV4;
 	list_add_tail_rcu(&addr->anode, &ipvlan->addrs);
 	ipvlan->ipv4cnt++;
-	ipvlan_ht_addr_add(ipvlan, addr);
+	/* If the interface is not up, the address will be added to the hash
+	 * list by ipvlan_open.
+	 */
+	if (netif_running(ipvlan->dev))
+		ipvlan_ht_addr_add(ipvlan, addr);
 	ipvlan_set_broadcast_mac_filter(ipvlan, true);
 
 	return 0;
-- 
1.8.3.1

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