From 7bf2357524408b97fec58344caf7397f8140c3fd Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Wed, 4 Jul 2012 21:23:25 -0400 Subject: net: feed /dev/random with the MAC address when registering a device Cc: David Miller Cc: Linus Torvalds Signed-off-by: "Theodore Ts'o" Cc: stable@vger.kernel.org --- net/core/dev.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'net/core/dev.c') diff --git a/net/core/dev.c b/net/core/dev.c index 6df214041a5e..bdd1e88f60d3 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1172,6 +1172,7 @@ static int __dev_open(struct net_device *dev) net_dmaengine_get(); dev_set_rx_mode(dev); dev_activate(dev); + add_device_randomness(dev->dev_addr, dev->addr_len); } return ret; @@ -4763,6 +4764,7 @@ int dev_set_mac_address(struct net_device *dev, struct sockaddr *sa) err = ops->ndo_set_mac_address(dev, sa); if (!err) call_netdevice_notifiers(NETDEV_CHANGEADDR, dev); + add_device_randomness(dev->dev_addr, dev->addr_len); return err; } EXPORT_SYMBOL(dev_set_mac_address); @@ -5541,6 +5543,7 @@ int register_netdevice(struct net_device *dev) dev_init_scheduler(dev); dev_hold(dev); list_netdevice(dev); + add_device_randomness(dev->dev_addr, dev->addr_len); /* Notify protocols, that a new device appeared. */ ret = call_netdevice_notifiers(NETDEV_REGISTER, dev); -- cgit v1.2.3 From b4b9e3558508980fc0cd161a545ffb55a1f13ee9 Mon Sep 17 00:00:00 2001 From: Mel Gorman Date: Tue, 31 Jul 2012 16:44:26 -0700 Subject: netvm: set PF_MEMALLOC as appropriate during SKB processing In order to make sure pfmemalloc packets receive all memory needed to proceed, ensure processing of pfmemalloc SKBs happens under PF_MEMALLOC. This is limited to a subset of protocols that are expected to be used for writing to swap. Taps are not allowed to use PF_MEMALLOC as these are expected to communicate with userspace processes which could be paged out. [a.p.zijlstra@chello.nl: Ideas taken from various patches] [jslaby@suse.cz: Lock imbalance fix] Signed-off-by: Mel Gorman Acked-by: David S. Miller Cc: Neil Brown Cc: Peter Zijlstra Cc: Mike Christie Cc: Eric B Munson Cc: Eric Dumazet Cc: Sebastian Andrzej Siewior Cc: Mel Gorman Cc: Christoph Lameter Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/net/sock.h | 5 +++++ net/core/dev.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++------ net/core/sock.c | 16 ++++++++++++++++ 3 files changed, 68 insertions(+), 6 deletions(-) (limited to 'net/core/dev.c') diff --git a/include/net/sock.h b/include/net/sock.h index 81198632ac2a..43a470d40d76 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -754,8 +754,13 @@ static inline __must_check int sk_add_backlog(struct sock *sk, struct sk_buff *s return 0; } +extern int __sk_backlog_rcv(struct sock *sk, struct sk_buff *skb); + static inline int sk_backlog_rcv(struct sock *sk, struct sk_buff *skb) { + if (sk_memalloc_socks() && skb_pfmemalloc(skb)) + return __sk_backlog_rcv(sk, skb); + return sk->sk_backlog_rcv(sk, skb); } diff --git a/net/core/dev.c b/net/core/dev.c index 0ebaea16632f..ce132443d5d1 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -3155,6 +3155,23 @@ void netdev_rx_handler_unregister(struct net_device *dev) } EXPORT_SYMBOL_GPL(netdev_rx_handler_unregister); +/* + * Limit the use of PFMEMALLOC reserves to those protocols that implement + * the special handling of PFMEMALLOC skbs. + */ +static bool skb_pfmemalloc_protocol(struct sk_buff *skb) +{ + switch (skb->protocol) { + case __constant_htons(ETH_P_ARP): + case __constant_htons(ETH_P_IP): + case __constant_htons(ETH_P_IPV6): + case __constant_htons(ETH_P_8021Q): + return true; + default: + return false; + } +} + static int __netif_receive_skb(struct sk_buff *skb) { struct packet_type *ptype, *pt_prev; @@ -3164,14 +3181,27 @@ static int __netif_receive_skb(struct sk_buff *skb) bool deliver_exact = false; int ret = NET_RX_DROP; __be16 type; + unsigned long pflags = current->flags; net_timestamp_check(!netdev_tstamp_prequeue, skb); trace_netif_receive_skb(skb); + /* + * PFMEMALLOC skbs are special, they should + * - be delivered to SOCK_MEMALLOC sockets only + * - stay away from userspace + * - have bounded memory usage + * + * Use PF_MEMALLOC as this saves us from propagating the allocation + * context down to all allocation sites. + */ + if (sk_memalloc_socks() && skb_pfmemalloc(skb)) + current->flags |= PF_MEMALLOC; + /* if we've gotten here through NAPI, check netpoll */ if (netpoll_receive_skb(skb)) - return NET_RX_DROP; + goto out; orig_dev = skb->dev; @@ -3191,7 +3221,7 @@ another_round: if (skb->protocol == cpu_to_be16(ETH_P_8021Q)) { skb = vlan_untag(skb); if (unlikely(!skb)) - goto out; + goto unlock; } #ifdef CONFIG_NET_CLS_ACT @@ -3201,6 +3231,9 @@ another_round: } #endif + if (sk_memalloc_socks() && skb_pfmemalloc(skb)) + goto skip_taps; + list_for_each_entry_rcu(ptype, &ptype_all, list) { if (!ptype->dev || ptype->dev == skb->dev) { if (pt_prev) @@ -3209,13 +3242,18 @@ another_round: } } +skip_taps: #ifdef CONFIG_NET_CLS_ACT skb = handle_ing(skb, &pt_prev, &ret, orig_dev); if (!skb) - goto out; + goto unlock; ncls: #endif + if (sk_memalloc_socks() && skb_pfmemalloc(skb) + && !skb_pfmemalloc_protocol(skb)) + goto drop; + rx_handler = rcu_dereference(skb->dev->rx_handler); if (vlan_tx_tag_present(skb)) { if (pt_prev) { @@ -3225,7 +3263,7 @@ ncls: if (vlan_do_receive(&skb, !rx_handler)) goto another_round; else if (unlikely(!skb)) - goto out; + goto unlock; } if (rx_handler) { @@ -3235,7 +3273,7 @@ ncls: } switch (rx_handler(&skb)) { case RX_HANDLER_CONSUMED: - goto out; + goto unlock; case RX_HANDLER_ANOTHER: goto another_round; case RX_HANDLER_EXACT: @@ -3268,6 +3306,7 @@ ncls: else ret = pt_prev->func(skb, skb->dev, pt_prev, orig_dev); } else { +drop: atomic_long_inc(&skb->dev->rx_dropped); kfree_skb(skb); /* Jamal, now you will not able to escape explaining @@ -3276,8 +3315,10 @@ ncls: ret = NET_RX_DROP; } -out: +unlock: rcu_read_unlock(); +out: + tsk_restore_flags(current, pflags, PF_MEMALLOC); return ret; } diff --git a/net/core/sock.c b/net/core/sock.c index c8c5816289fe..32fdcd2d6e8f 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -298,6 +298,22 @@ void sk_clear_memalloc(struct sock *sk) } EXPORT_SYMBOL_GPL(sk_clear_memalloc); +int __sk_backlog_rcv(struct sock *sk, struct sk_buff *skb) +{ + int ret; + unsigned long pflags = current->flags; + + /* these should have been dropped before queueing */ + BUG_ON(!sock_flag(sk, SOCK_MEMALLOC)); + + current->flags |= PF_MEMALLOC; + ret = sk->sk_backlog_rcv(sk, skb); + tsk_restore_flags(current, pflags, PF_MEMALLOC); + + return ret; +} +EXPORT_SYMBOL(__sk_backlog_rcv); + #if defined(CONFIG_CGROUPS) #if !defined(CONFIG_NET_CLS_CGROUP) int net_cls_subsys_id = -1; -- cgit v1.2.3 From 30b678d844af3305cda5953467005cebb5d7b687 Mon Sep 17 00:00:00 2001 From: Ben Hutchings Date: Mon, 30 Jul 2012 15:57:00 +0000 Subject: net: Allow driver to limit number of GSO segments per skb A peer (or local user) may cause TCP to use a nominal MSS of as little as 88 (actual MSS of 76 with timestamps). Given that we have a sufficiently prodigious local sender and the peer ACKs quickly enough, it is nevertheless possible to grow the window for such a connection to the point that we will try to send just under 64K at once. This results in a single skb that expands to 861 segments. In some drivers with TSO support, such an skb will require hundreds of DMA descriptors; a substantial fraction of a TX ring or even more than a full ring. The TX queue selected for the skb may stall and trigger the TX watchdog repeatedly (since the problem skb will be retried after the TX reset). This particularly affects sfc, for which the issue is designated as CVE-2012-3412. Therefore: 1. Add the field net_device::gso_max_segs holding the device-specific limit. 2. In netif_skb_features(), if the number of segments is too high then mask out GSO features to force fall back to software GSO. Signed-off-by: Ben Hutchings Signed-off-by: David S. Miller --- include/linux/netdevice.h | 2 ++ net/core/dev.c | 4 ++++ 2 files changed, 6 insertions(+) (limited to 'net/core/dev.c') diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index eb06e58bed0b..a9db4f33407f 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -1300,6 +1300,8 @@ struct net_device { /* for setting kernel sock attribute on TCP connection setup */ #define GSO_MAX_SIZE 65536 unsigned int gso_max_size; +#define GSO_MAX_SEGS 65535 + u16 gso_max_segs; #ifdef CONFIG_DCB /* Data Center Bridging netlink ops */ diff --git a/net/core/dev.c b/net/core/dev.c index 0cb3fe8d8e72..f91abf800161 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -2134,6 +2134,9 @@ netdev_features_t netif_skb_features(struct sk_buff *skb) __be16 protocol = skb->protocol; netdev_features_t features = skb->dev->features; + if (skb_shinfo(skb)->gso_segs > skb->dev->gso_max_segs) + features &= ~NETIF_F_GSO_MASK; + if (protocol == htons(ETH_P_8021Q)) { struct vlan_ethhdr *veh = (struct vlan_ethhdr *)skb->data; protocol = veh->h_vlan_encapsulated_proto; @@ -5986,6 +5989,7 @@ struct net_device *alloc_netdev_mqs(int sizeof_priv, const char *name, dev_net_set(dev, &init_net); dev->gso_max_size = GSO_MAX_SIZE; + dev->gso_max_segs = GSO_MAX_SEGS; INIT_LIST_HEAD(&dev->napi_list); INIT_LIST_HEAD(&dev->unreg_list); -- cgit v1.2.3