[PATCH v2 net 2/2] geneve: avoid using stale geneve socket.
From: Pravin B Shelar <hidden>
Date: 2016-10-28 16:59:23
Subsystem:
networking drivers, the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
This patch is similar to earlier vxlan patch. Geneve device close operation frees geneve socket. This operation can race with geneve-xmit function which dereferences geneve socket. Following patch uses RCU mechanism to avoid this situation. Signed-off-by: Pravin B Shelar <redacted> Acked-by: John W. Linville <redacted> --- drivers/net/geneve.c | 45 ++++++++++++++++++++++++++++++++++----------- 1 file changed, 34 insertions(+), 11 deletions(-)
diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c
index 16af1ce..42edd7b 100644
--- a/drivers/net/geneve.c
+++ b/drivers/net/geneve.c@@ -58,9 +58,9 @@ struct geneve_dev { struct hlist_node hlist; /* vni hash table */ struct net *net; /* netns for packet i/o */ struct net_device *dev; /* netdev for geneve tunnel */ - struct geneve_sock *sock4; /* IPv4 socket used for geneve tunnel */ + struct geneve_sock __rcu *sock4; /* IPv4 socket used for geneve tunnel */ #if IS_ENABLED(CONFIG_IPV6) - struct geneve_sock *sock6; /* IPv6 socket used for geneve tunnel */ + struct geneve_sock __rcu *sock6; /* IPv6 socket used for geneve tunnel */ #endif u8 vni[3]; /* virtual network ID for tunnel */ u8 ttl; /* TTL override */
@@ -543,9 +543,19 @@ static void __geneve_sock_release(struct geneve_sock *gs) static void geneve_sock_release(struct geneve_dev *geneve) { - __geneve_sock_release(geneve->sock4); + struct geneve_sock *gs4 = rtnl_dereference(geneve->sock4); #if IS_ENABLED(CONFIG_IPV6) - __geneve_sock_release(geneve->sock6); + struct geneve_sock *gs6 = rtnl_dereference(geneve->sock6); + + rcu_assign_pointer(geneve->sock6, NULL); +#endif + + rcu_assign_pointer(geneve->sock4, NULL); + synchronize_net(); + + __geneve_sock_release(gs4); +#if IS_ENABLED(CONFIG_IPV6) + __geneve_sock_release(gs6); #endif }
@@ -586,10 +596,10 @@ static int geneve_sock_add(struct geneve_dev *geneve, bool ipv6) gs->flags = geneve->flags; #if IS_ENABLED(CONFIG_IPV6) if (ipv6) - geneve->sock6 = gs; + rcu_assign_pointer(geneve->sock6, gs); else #endif - geneve->sock4 = gs; + rcu_assign_pointer(geneve->sock4, gs); hash = geneve_net_vni_hash(geneve->vni); hlist_add_head_rcu(&geneve->hlist, &gs->vni_list[hash]);
@@ -603,9 +613,7 @@ static int geneve_open(struct net_device *dev) bool metadata = geneve->collect_md; int ret = 0; - geneve->sock4 = NULL; #if IS_ENABLED(CONFIG_IPV6) - geneve->sock6 = NULL; if (ipv6 || metadata) ret = geneve_sock_add(geneve, true); #endif
@@ -720,6 +728,9 @@ static struct rtable *geneve_get_v4_rt(struct sk_buff *skb, struct rtable *rt = NULL; __u8 tos; + if (!rcu_dereference(geneve->sock4)) + return ERR_PTR(-EIO); + memset(fl4, 0, sizeof(*fl4)); fl4->flowi4_mark = skb->mark; fl4->flowi4_proto = IPPROTO_UDP;
@@ -772,11 +783,15 @@ static struct dst_entry *geneve_get_v6_dst(struct sk_buff *skb, { bool use_cache = ip_tunnel_dst_cache_usable(skb, info); struct geneve_dev *geneve = netdev_priv(dev); - struct geneve_sock *gs6 = geneve->sock6; struct dst_entry *dst = NULL; struct dst_cache *dst_cache; + struct geneve_sock *gs6; __u8 prio; + gs6 = rcu_dereference(geneve->sock6); + if (!gs6) + return ERR_PTR(-EIO); + memset(fl6, 0, sizeof(*fl6)); fl6->flowi6_mark = skb->mark; fl6->flowi6_proto = IPPROTO_UDP;
@@ -842,7 +857,7 @@ static netdev_tx_t geneve_xmit_skb(struct sk_buff *skb, struct net_device *dev, struct ip_tunnel_info *info) { struct geneve_dev *geneve = netdev_priv(dev); - struct geneve_sock *gs4 = geneve->sock4; + struct geneve_sock *gs4; struct rtable *rt = NULL; const struct iphdr *iip; /* interior IP header */ int err = -EINVAL;
@@ -853,6 +868,10 @@ static netdev_tx_t geneve_xmit_skb(struct sk_buff *skb, struct net_device *dev, bool xnet = !net_eq(geneve->net, dev_net(geneve->dev)); u32 flags = geneve->flags; + gs4 = rcu_dereference(geneve->sock4); + if (!gs4) + goto tx_error; + if (geneve->collect_md) { if (unlikely(!info || !(info->mode & IP_TUNNEL_INFO_TX))) { netdev_dbg(dev, "no tunnel metadata\n");
@@ -932,9 +951,9 @@ static netdev_tx_t geneve6_xmit_skb(struct sk_buff *skb, struct net_device *dev, struct ip_tunnel_info *info) { struct geneve_dev *geneve = netdev_priv(dev); - struct geneve_sock *gs6 = geneve->sock6; struct dst_entry *dst = NULL; const struct iphdr *iip; /* interior IP header */ + struct geneve_sock *gs6; int err = -EINVAL; struct flowi6 fl6; __u8 prio, ttl;
@@ -943,6 +962,10 @@ static netdev_tx_t geneve6_xmit_skb(struct sk_buff *skb, struct net_device *dev, bool xnet = !net_eq(geneve->net, dev_net(geneve->dev)); u32 flags = geneve->flags; + gs6 = rcu_dereference(geneve->sock6); + if (!gs6) + goto tx_error; + if (geneve->collect_md) { if (unlikely(!info || !(info->mode & IP_TUNNEL_INFO_TX))) { netdev_dbg(dev, "no tunnel metadata\n");
--
1.9.1