From fceb9c3e38252992bbf1a3028cc2f7b871211533 Mon Sep 17 00:00:00 2001 From: pravin shelar Date: Fri, 28 Oct 2016 09:59:16 -0700 Subject: [PATCH] geneve: avoid using stale geneve socket. 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 Acked-by: John W. Linville Signed-off-by: David S. Miller --- 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 16af1ce99233..42edd7b7902f 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 @@ out: 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"); -- 2.20.1