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 --- net/core/dev.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'net/core/dev.c') diff --git a/net/core/dev.c b/net/core/dev.c index 0cb3fe8d8e7..f91abf80016 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 v1.2.3-70-g09d2 From 7364e445f62825758fa61195d237a5b8ecdd06ec Mon Sep 17 00:00:00 2001 From: Alexey Khoroshilov Date: Wed, 8 Aug 2012 00:33:25 +0000 Subject: net/core: Fix potential memory leak in dev_set_alias() Do not leak memory by updating pointer with potentially NULL realloc return value. Found by Linux Driver Verification project (linuxtesting.org). Signed-off-by: Alexey Khoroshilov Signed-off-by: David S. Miller --- net/core/dev.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'net/core/dev.c') diff --git a/net/core/dev.c b/net/core/dev.c index f91abf80016..a39354ee143 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1055,6 +1055,8 @@ rollback: */ int dev_set_alias(struct net_device *dev, const char *alias, size_t len) { + char *new_ifalias; + ASSERT_RTNL(); if (len >= IFALIASZ) @@ -1068,9 +1070,10 @@ int dev_set_alias(struct net_device *dev, const char *alias, size_t len) return 0; } - dev->ifalias = krealloc(dev->ifalias, len + 1, GFP_KERNEL); - if (!dev->ifalias) + new_ifalias = krealloc(dev->ifalias, len + 1, GFP_KERNEL); + if (!new_ifalias) return -ENOMEM; + dev->ifalias = new_ifalias; strlcpy(dev->ifalias, alias, len+1); return len; -- cgit v1.2.3-70-g09d2 From c0de08d04215031d68fa13af36f347a6cfa252ca Mon Sep 17 00:00:00 2001 From: Eric Leblond Date: Thu, 16 Aug 2012 22:02:58 +0000 Subject: af_packet: don't emit packet on orig fanout group If a packet is emitted on one socket in one group of fanout sockets, it is transmitted again. It is thus read again on one of the sockets of the fanout group. This result in a loop for software which generate packets when receiving one. This retransmission is not the intended behavior: a fanout group must behave like a single socket. The packet should not be transmitted on a socket if it originates from a socket belonging to the same fanout group. This patch fixes the issue by changing the transmission check to take fanout group info account. Reported-by: Aleksandr Kotov Signed-off-by: Eric Leblond Signed-off-by: David S. Miller --- include/linux/netdevice.h | 2 ++ net/core/dev.c | 16 ++++++++++++++-- net/packet/af_packet.c | 9 +++++++++ 3 files changed, 25 insertions(+), 2 deletions(-) (limited to 'net/core/dev.c') diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 3560d688161..59dc05f3824 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -1522,6 +1522,8 @@ struct packet_type { struct sk_buff **(*gro_receive)(struct sk_buff **head, struct sk_buff *skb); int (*gro_complete)(struct sk_buff *skb); + bool (*id_match)(struct packet_type *ptype, + struct sock *sk); void *af_packet_priv; struct list_head list; }; diff --git a/net/core/dev.c b/net/core/dev.c index a39354ee143..debd9372472 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1642,6 +1642,19 @@ static inline int deliver_skb(struct sk_buff *skb, return pt_prev->func(skb, skb->dev, pt_prev, orig_dev); } +static inline bool skb_loop_sk(struct packet_type *ptype, struct sk_buff *skb) +{ + if (ptype->af_packet_priv == NULL) + return false; + + if (ptype->id_match) + return ptype->id_match(ptype, skb->sk); + else if ((struct sock *)ptype->af_packet_priv == skb->sk) + return true; + + return false; +} + /* * Support routine. Sends outgoing frames to any network * taps currently in use. @@ -1659,8 +1672,7 @@ static void dev_queue_xmit_nit(struct sk_buff *skb, struct net_device *dev) * they originated from - MvS (miquels@drinkel.ow.org) */ if ((ptype->dev == dev || !ptype->dev) && - (ptype->af_packet_priv == NULL || - (struct sock *)ptype->af_packet_priv != skb->sk)) { + (!skb_loop_sk(ptype, skb))) { if (pt_prev) { deliver_skb(skb2, pt_prev, skb->dev); pt_prev = ptype; diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index 8ac890a1a4c..aee7196aac3 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -1273,6 +1273,14 @@ static void __fanout_unlink(struct sock *sk, struct packet_sock *po) spin_unlock(&f->lock); } +bool match_fanout_group(struct packet_type *ptype, struct sock * sk) +{ + if (ptype->af_packet_priv == (void*)((struct packet_sock *)sk)->fanout) + return true; + + return false; +} + static int fanout_add(struct sock *sk, u16 id, u16 type_flags) { struct packet_sock *po = pkt_sk(sk); @@ -1325,6 +1333,7 @@ static int fanout_add(struct sock *sk, u16 id, u16 type_flags) match->prot_hook.dev = po->prot_hook.dev; match->prot_hook.func = packet_rcv_fanout; match->prot_hook.af_packet_priv = match; + match->prot_hook.id_match = match_fanout_group; dev_add_pack(&match->prot_hook); list_add(&match->list, &fanout_list); } -- cgit v1.2.3-70-g09d2 From 3de7a37b02f607716753dc669c1dca4f71db08fc Mon Sep 17 00:00:00 2001 From: Randy Dunlap Date: Sat, 18 Aug 2012 14:36:44 +0000 Subject: net/core/dev.c: fix kernel-doc warning Fix kernel-doc warning: Warning(net/core/dev.c:5745): No description found for parameter 'dev' Signed-off-by: Randy Dunlap Cc: "David S. Miller" Cc: netdev@vger.kernel.org Signed-off-by: David S. Miller --- net/core/dev.c | 1 + 1 file changed, 1 insertion(+) (limited to 'net/core/dev.c') diff --git a/net/core/dev.c b/net/core/dev.c index debd9372472..83988362805 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -5744,6 +5744,7 @@ EXPORT_SYMBOL(netdev_refcnt_read); /** * netdev_wait_allrefs - wait until all references are gone. + * @dev: target net_device * * This is called when unregistering network devices. * -- cgit v1.2.3-70-g09d2 From 6862234238e84648c305526af2edd98badcad1e0 Mon Sep 17 00:00:00 2001 From: Chema Gonzalez Date: Fri, 7 Sep 2012 13:40:50 +0000 Subject: net: small bug on rxhash calculation In the current rxhash calculation function, while the sorting of the ports/addrs is coherent (you get the same rxhash for packets sharing the same 4-tuple, in both directions), ports and addrs are sorted independently. This implies packets from a connection between the same addresses but crossed ports hash to the same rxhash. For example, traffic between A=S:l and B=L:s is hashed (in both directions) from {L, S, {s, l}}. The same rxhash is obtained for packets between C=S:s and D=L:l. This patch ensures that you either swap both addrs and ports, or you swap none. Traffic between A and B, and traffic between C and D, get their rxhash from different sources ({L, S, {l, s}} for A<->B, and {L, S, {s, l}} for C<->D) The patch is co-written with Eric Dumazet Signed-off-by: Chema Gonzalez Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/core/dev.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) (limited to 'net/core/dev.c') diff --git a/net/core/dev.c b/net/core/dev.c index 83988362805..d7fe32c946c 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -2647,15 +2647,16 @@ void __skb_get_rxhash(struct sk_buff *skb) if (!skb_flow_dissect(skb, &keys)) return; - if (keys.ports) { - if ((__force u16)keys.port16[1] < (__force u16)keys.port16[0]) - swap(keys.port16[0], keys.port16[1]); + if (keys.ports) skb->l4_rxhash = 1; - } /* get a consistent hash (same value on both flow directions) */ - if ((__force u32)keys.dst < (__force u32)keys.src) + if (((__force u32)keys.dst < (__force u32)keys.src) || + (((__force u32)keys.dst == (__force u32)keys.src) && + ((__force u16)keys.port16[1] < (__force u16)keys.port16[0]))) { swap(keys.dst, keys.src); + swap(keys.port16[0], keys.port16[1]); + } hash = jhash_3words((__force u32)keys.dst, (__force u32)keys.src, -- cgit v1.2.3-70-g09d2 From 0e698bf6624c469cd4f3f391247b142963ca9c4e Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Sat, 15 Sep 2012 22:44:16 +0000 Subject: net: fix memory leak on oom with zerocopy If orphan flags fails, we don't free the skb on receive, which leaks the skb memory. Return value was also wrong: netif_receive_skb is supposed to return NET_RX_DROP, not ENOMEM. Signed-off-by: Michael S. Tsirkin Signed-off-by: David S. Miller --- net/core/dev.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net/core/dev.c') diff --git a/net/core/dev.c b/net/core/dev.c index d7fe32c946c..ac7609d8518 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -3322,7 +3322,7 @@ ncls: if (pt_prev) { if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC))) - ret = -ENOMEM; + goto drop; else ret = pt_prev->func(skb, skb->dev, pt_prev, orig_dev); } else { -- cgit v1.2.3-70-g09d2 From c0d680e577ff171e7b37dbdb1b1bf5451e851f04 Mon Sep 17 00:00:00 2001 From: Ed Cashin Date: Wed, 19 Sep 2012 15:49:00 +0000 Subject: net: do not disable sg for packets requiring no checksum A change in a series of VLAN-related changes appears to have inadvertently disabled the use of the scatter gather feature of network cards for transmission of non-IP ethernet protocols like ATA over Ethernet (AoE). Below is a reference to the commit that introduces a "harmonize_features" function that turns off scatter gather when the NIC does not support hardware checksumming for the ethernet protocol of an sk buff. commit f01a5236bd4b140198fbcc550f085e8361fd73fa Author: Jesse Gross Date: Sun Jan 9 06:23:31 2011 +0000 net offloading: Generalize netif_get_vlan_features(). The can_checksum_protocol function is not equipped to consider a protocol that does not require checksumming. Calling it for a protocol that requires no checksum is inappropriate. The patch below has harmonize_features call can_checksum_protocol when the protocol needs a checksum, so that the network layer is not forced to perform unnecessary skb linearization on the transmission of AoE packets. Unnecessary linearization results in decreased performance and increased memory pressure, as reported here: http://www.spinics.net/lists/linux-mm/msg15184.html The problem has probably not been widely experienced yet, because only recently has the kernel.org-distributed aoe driver acquired the ability to use payloads of over a page in size, with the patchset recently included in the mm tree: https://lkml.org/lkml/2012/8/28/140 The coraid.com-distributed aoe driver already could use payloads of greater than a page in size, but its users generally do not use the newest kernels. Signed-off-by: Ed Cashin Signed-off-by: David S. Miller --- net/core/dev.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'net/core/dev.c') diff --git a/net/core/dev.c b/net/core/dev.c index ac7609d8518..89e33a5d4d9 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -2134,7 +2134,8 @@ static bool can_checksum_protocol(netdev_features_t features, __be16 protocol) static netdev_features_t harmonize_features(struct sk_buff *skb, __be16 protocol, netdev_features_t features) { - if (!can_checksum_protocol(features, protocol)) { + if (skb->ip_summed != CHECKSUM_NONE && + !can_checksum_protocol(features, protocol)) { features &= ~NETIF_F_ALL_CSUM; features &= ~NETIF_F_SG; } else if (illegal_highdma(skb->dev, skb)) { -- cgit v1.2.3-70-g09d2