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Message-Id: <1477673956-127319-1-git-send-email-pshelar@ovn.org>
Date: Fri, 28 Oct 2016 09:59:15 -0700
From: Pravin B Shelar <pshelar@....org>
To: netdev@...r.kernel.org
Cc: Pravin B Shelar <pshelar@....org>
Subject: [PATCH v2 net 1/2] vxlan: avoid using stale vxlan socket.
When vxlan device is closed vxlan socket is freed. This
operation can race with vxlan-xmit function which
dereferences vxlan socket. Following patch uses RCU
mechanism to avoid this situation.
Signed-off-by: Pravin B Shelar <pshelar@....org>
---
drivers/net/vxlan.c | 80 +++++++++++++++++++++++++++++++++--------------------
include/net/vxlan.h | 4 +--
2 files changed, 52 insertions(+), 32 deletions(-)
diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
index c1639a3..f3c2fa3 100644
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -943,17 +943,20 @@ static bool vxlan_snoop(struct net_device *dev,
static bool vxlan_group_used(struct vxlan_net *vn, struct vxlan_dev *dev)
{
struct vxlan_dev *vxlan;
+ struct vxlan_sock *sock4;
+ struct vxlan_sock *sock6 = NULL;
unsigned short family = dev->default_dst.remote_ip.sa.sa_family;
+ sock4 = rtnl_dereference(dev->vn4_sock);
+
/* The vxlan_sock is only used by dev, leaving group has
* no effect on other vxlan devices.
*/
- if (family == AF_INET && dev->vn4_sock &&
- atomic_read(&dev->vn4_sock->refcnt) == 1)
+ if (family == AF_INET && sock4 && atomic_read(&sock4->refcnt) == 1)
return false;
#if IS_ENABLED(CONFIG_IPV6)
- if (family == AF_INET6 && dev->vn6_sock &&
- atomic_read(&dev->vn6_sock->refcnt) == 1)
+ sock6 = rtnl_dereference(dev->vn6_sock);
+ if (family == AF_INET6 && sock6 && atomic_read(&sock6->refcnt) == 1)
return false;
#endif
@@ -961,10 +964,12 @@ static bool vxlan_group_used(struct vxlan_net *vn, struct vxlan_dev *dev)
if (!netif_running(vxlan->dev) || vxlan == dev)
continue;
- if (family == AF_INET && vxlan->vn4_sock != dev->vn4_sock)
+ if (family == AF_INET &&
+ rtnl_dereference(vxlan->vn4_sock) != sock4)
continue;
#if IS_ENABLED(CONFIG_IPV6)
- if (family == AF_INET6 && vxlan->vn6_sock != dev->vn6_sock)
+ if (family == AF_INET6 &&
+ rtnl_dereference(vxlan->vn6_sock) != sock6)
continue;
#endif
@@ -1005,22 +1010,25 @@ static bool __vxlan_sock_release_prep(struct vxlan_sock *vs)
static void vxlan_sock_release(struct vxlan_dev *vxlan)
{
- bool ipv4 = __vxlan_sock_release_prep(vxlan->vn4_sock);
+ struct vxlan_sock *sock4 = rtnl_dereference(vxlan->vn4_sock);
#if IS_ENABLED(CONFIG_IPV6)
- bool ipv6 = __vxlan_sock_release_prep(vxlan->vn6_sock);
+ struct vxlan_sock *sock6 = rtnl_dereference(vxlan->vn6_sock);
+
+ rcu_assign_pointer(vxlan->vn6_sock, NULL);
#endif
+ rcu_assign_pointer(vxlan->vn4_sock, NULL);
synchronize_net();
- if (ipv4) {
- udp_tunnel_sock_release(vxlan->vn4_sock->sock);
- kfree(vxlan->vn4_sock);
+ if (__vxlan_sock_release_prep(sock4)) {
+ udp_tunnel_sock_release(sock4->sock);
+ kfree(sock4);
}
#if IS_ENABLED(CONFIG_IPV6)
- if (ipv6) {
- udp_tunnel_sock_release(vxlan->vn6_sock->sock);
- kfree(vxlan->vn6_sock);
+ if (__vxlan_sock_release_prep(sock6)) {
+ udp_tunnel_sock_release(sock6->sock);
+ kfree(sock6);
}
#endif
}
@@ -1036,18 +1044,21 @@ static int vxlan_igmp_join(struct vxlan_dev *vxlan)
int ret = -EINVAL;
if (ip->sa.sa_family == AF_INET) {
+ struct vxlan_sock *sock4 = rtnl_dereference(vxlan->vn4_sock);
struct ip_mreqn mreq = {
.imr_multiaddr.s_addr = ip->sin.sin_addr.s_addr,
.imr_ifindex = ifindex,
};
- sk = vxlan->vn4_sock->sock->sk;
+ sk = sock4->sock->sk;
lock_sock(sk);
ret = ip_mc_join_group(sk, &mreq);
release_sock(sk);
#if IS_ENABLED(CONFIG_IPV6)
} else {
- sk = vxlan->vn6_sock->sock->sk;
+ struct vxlan_sock *sock6 = rtnl_dereference(vxlan->vn6_sock);
+
+ sk = sock6->sock->sk;
lock_sock(sk);
ret = ipv6_stub->ipv6_sock_mc_join(sk, ifindex,
&ip->sin6.sin6_addr);
@@ -1067,18 +1078,21 @@ static int vxlan_igmp_leave(struct vxlan_dev *vxlan)
int ret = -EINVAL;
if (ip->sa.sa_family == AF_INET) {
+ struct vxlan_sock *sock4 = rtnl_dereference(vxlan->vn4_sock);
struct ip_mreqn mreq = {
.imr_multiaddr.s_addr = ip->sin.sin_addr.s_addr,
.imr_ifindex = ifindex,
};
- sk = vxlan->vn4_sock->sock->sk;
+ sk = sock4->sock->sk;
lock_sock(sk);
ret = ip_mc_leave_group(sk, &mreq);
release_sock(sk);
#if IS_ENABLED(CONFIG_IPV6)
} else {
- sk = vxlan->vn6_sock->sock->sk;
+ struct vxlan_sock *sock6 = rtnl_dereference(vxlan->vn6_sock);
+
+ sk = sock6->sock->sk;
lock_sock(sk);
ret = ipv6_stub->ipv6_sock_mc_drop(sk, ifindex,
&ip->sin6.sin6_addr);
@@ -1828,11 +1842,15 @@ static struct dst_entry *vxlan6_get_route(struct vxlan_dev *vxlan,
struct dst_cache *dst_cache,
const struct ip_tunnel_info *info)
{
+ struct vxlan_sock *sock6 = rcu_dereference(vxlan->vn6_sock);
bool use_cache = ip_tunnel_dst_cache_usable(skb, info);
struct dst_entry *ndst;
struct flowi6 fl6;
int err;
+ if (!sock6)
+ return ERR_PTR(-EIO);
+
if (tos && !info)
use_cache = false;
if (use_cache) {
@@ -1850,7 +1868,7 @@ static struct dst_entry *vxlan6_get_route(struct vxlan_dev *vxlan,
fl6.flowi6_proto = IPPROTO_UDP;
err = ipv6_stub->ipv6_dst_lookup(vxlan->net,
- vxlan->vn6_sock->sock->sk,
+ sock6->sock->sk,
&ndst, &fl6);
if (err < 0)
return ERR_PTR(err);
@@ -1995,9 +2013,11 @@ static void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
}
if (dst->sa.sa_family == AF_INET) {
- if (!vxlan->vn4_sock)
+ struct vxlan_sock *sock4 = rcu_dereference(vxlan->vn4_sock);
+
+ if (!sock4)
goto drop;
- sk = vxlan->vn4_sock->sock->sk;
+ sk = sock4->sock->sk;
rt = vxlan_get_route(vxlan, skb,
rdst ? rdst->remote_ifindex : 0, tos,
@@ -2050,12 +2070,13 @@ static void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
src_port, dst_port, xnet, !udp_sum);
#if IS_ENABLED(CONFIG_IPV6)
} else {
+ struct vxlan_sock *sock6 = rcu_dereference(vxlan->vn6_sock);
struct dst_entry *ndst;
u32 rt6i_flags;
- if (!vxlan->vn6_sock)
+ if (!sock6)
goto drop;
- sk = vxlan->vn6_sock->sock->sk;
+ sk = sock6->sock->sk;
ndst = vxlan6_get_route(vxlan, skb,
rdst ? rdst->remote_ifindex : 0, tos,
@@ -2415,9 +2436,10 @@ static int vxlan_fill_metadata_dst(struct net_device *dev, struct sk_buff *skb)
dport = info->key.tp_dst ? : vxlan->cfg.dst_port;
if (ip_tunnel_info_af(info) == AF_INET) {
+ struct vxlan_sock *sock4 = rcu_dereference(vxlan->vn4_sock);
struct rtable *rt;
- if (!vxlan->vn4_sock)
+ if (!sock4)
return -EINVAL;
rt = vxlan_get_route(vxlan, skb, 0, info->key.tos,
info->key.u.ipv4.dst,
@@ -2429,8 +2451,6 @@ static int vxlan_fill_metadata_dst(struct net_device *dev, struct sk_buff *skb)
#if IS_ENABLED(CONFIG_IPV6)
struct dst_entry *ndst;
- if (!vxlan->vn6_sock)
- return -EINVAL;
ndst = vxlan6_get_route(vxlan, skb, 0, info->key.tos,
info->key.label, &info->key.u.ipv6.dst,
&info->key.u.ipv6.src, NULL, info);
@@ -2740,10 +2760,10 @@ static int __vxlan_sock_add(struct vxlan_dev *vxlan, bool ipv6)
return PTR_ERR(vs);
#if IS_ENABLED(CONFIG_IPV6)
if (ipv6)
- vxlan->vn6_sock = vs;
+ rcu_assign_pointer(vxlan->vn6_sock, vs);
else
#endif
- vxlan->vn4_sock = vs;
+ rcu_assign_pointer(vxlan->vn4_sock, vs);
vxlan_vs_add_dev(vs, vxlan);
return 0;
}
@@ -2754,9 +2774,9 @@ static int vxlan_sock_add(struct vxlan_dev *vxlan)
bool metadata = vxlan->flags & VXLAN_F_COLLECT_METADATA;
int ret = 0;
- vxlan->vn4_sock = NULL;
+ RCU_INIT_POINTER(vxlan->vn4_sock, NULL);
#if IS_ENABLED(CONFIG_IPV6)
- vxlan->vn6_sock = NULL;
+ RCU_INIT_POINTER(vxlan->vn6_sock, NULL);
if (ipv6 || metadata)
ret = __vxlan_sock_add(vxlan, true);
#endif
diff --git a/include/net/vxlan.h b/include/net/vxlan.h
index 0255613..308adc4 100644
--- a/include/net/vxlan.h
+++ b/include/net/vxlan.h
@@ -225,9 +225,9 @@ struct vxlan_config {
struct vxlan_dev {
struct hlist_node hlist; /* vni hash table */
struct list_head next; /* vxlan's per namespace list */
- struct vxlan_sock *vn4_sock; /* listening socket for IPv4 */
+ struct vxlan_sock __rcu *vn4_sock; /* listening socket for IPv4 */
#if IS_ENABLED(CONFIG_IPV6)
- struct vxlan_sock *vn6_sock; /* listening socket for IPv6 */
+ struct vxlan_sock __rcu *vn6_sock; /* listening socket for IPv6 */
#endif
struct net_device *dev;
struct net *net; /* netns for packet i/o */
--
1.9.1
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