From e4961b0768852d9eb7383e1a5df178eacb714656 Mon Sep 17 00:00:00 2001 From: Ido Schimmel Date: Wed, 19 Oct 2016 16:57:08 +0300 Subject: net: core: Correctly iterate over lower adjacency list Tamir reported the following trace when processing ARP requests received via a vlan device on top of a VLAN-aware bridge: NMI watchdog: BUG: soft lockup - CPU#1 stuck for 22s! [swapper/1:0] [...] CPU: 1 PID: 0 Comm: swapper/1 Tainted: G W 4.8.0-rc7 #1 Hardware name: Mellanox Technologies Ltd. "MSN2100-CB2F"/"SA001017", BIOS 5.6.5 06/07/2016 task: ffff88017edfea40 task.stack: ffff88017ee10000 RIP: 0010:[] [] netdev_all_lower_get_next_rcu+0x33/0x60 [...] Call Trace: [] mlxsw_sp_port_lower_dev_hold+0x5a/0xa0 [mlxsw_spectrum] [] mlxsw_sp_router_netevent_event+0x80/0x150 [mlxsw_spectrum] [] notifier_call_chain+0x4a/0x70 [] atomic_notifier_call_chain+0x1a/0x20 [] call_netevent_notifiers+0x1b/0x20 [] neigh_update+0x306/0x740 [] neigh_event_ns+0x4e/0xb0 [] arp_process+0x66f/0x700 [] ? common_interrupt+0x8c/0x8c [] arp_rcv+0x139/0x1d0 [] ? vlan_do_receive+0xda/0x320 [] __netif_receive_skb_core+0x524/0xab0 [] ? dev_queue_xmit+0x10/0x20 [] ? br_forward_finish+0x3d/0xc0 [bridge] [] ? br_handle_vlan+0xf6/0x1b0 [bridge] [] __netif_receive_skb+0x18/0x60 [] netif_receive_skb_internal+0x40/0xb0 [] netif_receive_skb+0x1c/0x70 [] br_pass_frame_up+0xc6/0x160 [bridge] [] ? deliver_clone+0x37/0x50 [bridge] [] ? br_flood+0xcc/0x160 [bridge] [] br_handle_frame_finish+0x224/0x4f0 [bridge] [] br_handle_frame+0x174/0x300 [bridge] [] __netif_receive_skb_core+0x329/0xab0 [] ? find_next_bit+0x15/0x20 [] ? cpumask_next_and+0x32/0x50 [] ? load_balance+0x178/0x9b0 [] __netif_receive_skb+0x18/0x60 [] netif_receive_skb_internal+0x40/0xb0 [] netif_receive_skb+0x1c/0x70 [] mlxsw_sp_rx_listener_func+0x61/0xb0 [mlxsw_spectrum] [] mlxsw_core_skb_receive+0x187/0x200 [mlxsw_core] [] mlxsw_pci_cq_tasklet+0x63a/0x9b0 [mlxsw_pci] [] tasklet_action+0xf6/0x110 [] __do_softirq+0xf6/0x280 [] irq_exit+0xdf/0xf0 [] do_IRQ+0x54/0xd0 [] common_interrupt+0x8c/0x8c The problem is that netdev_all_lower_get_next_rcu() never advances the iterator, thereby causing the loop over the lower adjacency list to run forever. Fix this by advancing the iterator and avoid the infinite loop. Fixes: 7ce856aaaf13 ("mlxsw: spectrum: Add couple of lower device helper functions") Signed-off-by: Ido Schimmel Reported-by: Tamir Winetroub Reviewed-by: Jiri Pirko Acked-by: David Ahern Signed-off-by: David S. Miller --- include/linux/netdevice.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux/netdevice.h') diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 136ae6bbe81e..465e128699a1 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -3877,7 +3877,7 @@ struct net_device *netdev_all_lower_get_next_rcu(struct net_device *dev, ldev = netdev_all_lower_get_next(dev, &(iter))) #define netdev_for_each_all_lower_dev_rcu(dev, ldev, iter) \ - for (iter = (dev)->all_adj_list.lower.next, \ + for (iter = &(dev)->all_adj_list.lower, \ ldev = netdev_all_lower_get_next_rcu(dev, &(iter)); \ ldev; \ ldev = netdev_all_lower_get_next_rcu(dev, &(iter))) -- cgit v1.2.3 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 --- include/linux/netdevice.h | 39 ++++++++++++++++++++++++++++++++++++++- 1 file changed, 38 insertions(+), 1 deletion(-) (limited to 'include/linux/netdevice.h') diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 465e128699a1..91ee3643ccc8 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -2169,7 +2169,10 @@ struct napi_gro_cb { /* Used to determine if flush_id can be ignored */ u8 is_atomic:1; - /* 5 bit hole */ + /* Number of gro_receive callbacks this packet already went through */ + u8 recursion_counter:4; + + /* 1 bit hole */ /* used to support CHECKSUM_COMPLETE for tunneling protocols */ __wsum csum; @@ -2180,6 +2183,40 @@ struct napi_gro_cb { #define NAPI_GRO_CB(skb) ((struct napi_gro_cb *)(skb)->cb) +#define GRO_RECURSION_LIMIT 15 +static inline int gro_recursion_inc_test(struct sk_buff *skb) +{ + return ++NAPI_GRO_CB(skb)->recursion_counter == GRO_RECURSION_LIMIT; +} + +typedef struct sk_buff **(*gro_receive_t)(struct sk_buff **, struct sk_buff *); +static inline struct sk_buff **call_gro_receive(gro_receive_t cb, + struct sk_buff **head, + struct sk_buff *skb) +{ + if (unlikely(gro_recursion_inc_test(skb))) { + NAPI_GRO_CB(skb)->flush |= 1; + return NULL; + } + + return cb(head, skb); +} + +typedef struct sk_buff **(*gro_receive_sk_t)(struct sock *, struct sk_buff **, + struct sk_buff *); +static inline struct sk_buff **call_gro_receive_sk(gro_receive_sk_t cb, + struct sock *sk, + struct sk_buff **head, + struct sk_buff *skb) +{ + if (unlikely(gro_recursion_inc_test(skb))) { + NAPI_GRO_CB(skb)->flush |= 1; + return NULL; + } + + return cb(sk, head, skb); +} + struct packet_type { __be16 type; /* This is really htons(ether_type). */ struct net_device *dev; /* NULL is wildcarded here */ -- cgit v1.2.3