From fcd91dd449867c6bfe56a81cabba76b829fd05cd Mon Sep 17 00:00:00 2001 From: Sabrina Dubroca Date: Thu, 20 Oct 2016 15:58:02 +0200 Subject: net: add recursion limit to GRO MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Currently, GRO can do unlimited recursion through the gro_receive handlers. This was fixed for tunneling protocols by limiting tunnel GRO to one level with encap_mark, but both VLAN and TEB still have this problem. Thus, the kernel is vulnerable to a stack overflow, if we receive a packet composed entirely of VLAN headers. This patch adds a recursion counter to the GRO layer to prevent stack overflow. When a gro_receive function hits the recursion limit, GRO is aborted for this skb and it is processed normally. This recursion counter is put in the GRO CB, but could be turned into a percpu counter if we run out of space in the CB. Thanks to Vladimír Beneš for the initial bug report. Fixes: CVE-2016-7039 Fixes: 9b174d88c257 ("net: Add Transparent Ethernet Bridging GRO support.") Fixes: 66e5133f19e9 ("vlan: Add GRO support for non hardware accelerated vlan") Signed-off-by: Sabrina Dubroca Reviewed-by: Jiri Benc Acked-by: Hannes Frederic Sowa Acked-by: Tom Herbert Signed-off-by: David S. Miller --- drivers/net/geneve.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/net/geneve.c') diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c index 3c20e87bb761..16af1ce99233 100644 --- a/drivers/net/geneve.c +++ b/drivers/net/geneve.c @@ -453,7 +453,7 @@ static struct sk_buff **geneve_gro_receive(struct sock *sk, skb_gro_pull(skb, gh_len); skb_gro_postpull_rcsum(skb, gh, gh_len); - pp = ptype->callbacks.gro_receive(head, skb); + pp = call_gro_receive(ptype->callbacks.gro_receive, head, skb); flush = 0; out_unlock: -- cgit v1.2.3 From fceb9c3e38252992bbf1a3028cc2f7b871211533 Mon Sep 17 00:00:00 2001 From: pravin shelar Date: Fri, 28 Oct 2016 09:59:16 -0700 Subject: 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(-) (limited to 'drivers/net/geneve.c') 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"); -- cgit v1.2.3