linux-toradex.git/net/core/dev.c, branch v3.14.57

net: call rcu_read_lock early in process_backlog

2015-10-01T09:36:20+00:00

[ Upstream commit 2c17d27c36dcce2b6bf689f41a46b9e909877c21 ]

Incoming packet should be either in backlog queue or
in RCU read-side section. Otherwise, the final sequence of
flush_backlog() and synchronize_net() may miss packets
that can run without device reference:

CPU 1                  CPU 2
                       skb->dev: no reference
                       process_backlog:__skb_dequeue
                       process_backlog:local_irq_enable

on_each_cpu for
flush_backlog =>       IPI(hardirq): flush_backlog
                       - packet not found in backlog

                       CPU delayed ...
synchronize_net
- no ongoing RCU
read-side sections

netdev_run_todo,
rcu_barrier: no
ongoing callbacks
                       __netif_receive_skb_core:rcu_read_lock
                       - too late
free dev
                       process packet for freed dev

Fixes: 6e583ce5242f ("net: eliminate refcounting in backlog queue")
Cc: Eric W. Biederman 
Cc: Stephen Hemminger 
Signed-off-by: Julian Anastasov 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net: do not process device backlog during unregistration

2015-10-01T09:36:20+00:00

[ Upstream commit e9e4dd3267d0c5234c5c0f47440456b10875dec9 ]

commit 381c759d9916 ("ipv4: Avoid crashing in ip_error")
fixes a problem where processed packet comes from device
with destroyed inetdev (dev->ip_ptr). This is not expected
because inetdev_destroy is called in NETDEV_UNREGISTER
phase and packets should not be processed after
dev_close_many() and synchronize_net(). Above fix is still
required because inetdev_destroy can be called for other
reasons. But it shows the real problem: backlog can keep
packets for long time and they do not hold reference to
device. Such packets are then delivered to upper levels
at the same time when device is unregistered.
Calling flush_backlog after NETDEV_UNREGISTER_FINAL still
accounts all packets from backlog but before that some packets
continue to be delivered to upper levels long after the
synchronize_net call which is supposed to wait the last
ones. Also, as Eric pointed out, processed packets, mostly
from other devices, can continue to add new packets to backlog.

Fix the problem by moving flush_backlog early, after the
device driver is stopped and before the synchronize_net() call.
Then use netif_running check to make sure we do not add more
packets to backlog. We have to do it in enqueue_to_backlog
context when the local IRQ is disabled. As result, after the
flush_backlog and synchronize_net sequence all packets
should be accounted.

Thanks to Eric W. Biederman for the test script and his
valuable feedback!

Reported-by: Vittorio Gambaletta 
Fixes: 6e583ce5242f ("net: eliminate refcounting in backlog queue")
Cc: Eric W. Biederman 
Cc: Stephen Hemminger 
Signed-off-by: Julian Anastasov 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net: graceful exit from netif_alloc_netdev_queues()

2015-10-01T09:36:19+00:00

[ Upstream commit d339727c2b1a10f25e6636670ab6e1841170e328 ]

User space can crash kernel with

ip link add ifb10 numtxqueues 100000 type ifb

We must replace a BUG_ON() by proper test and return -EINVAL for
crazy values.

Fixes: 60877a32bce00 ("net: allow large number of tx queues")
Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net: core: Correct an over-stringent device loop detection.

2015-06-23T00:01:16+00:00

[ Upstream commit d66bf7dd27573ee5ea90484899ee952c19ccb194 ]

The code in __netdev_upper_dev_link() has an over-stringent
loop detection logic that actually prevents valid configurations
from working correctly.

In particular, the logic returns an error if an upper device
is already in the list of all upper devices for a given dev.
This particular check seems to be a overzealous as it disallows
perfectly valid configurations.  For example:
  # ip l a link eth0 name eth0.10 type vlan id 10
  # ip l a dev br0 typ bridge
  # ip l s eth0.10 master br0
  # ip l s eth0 master br0  <--- Will fail

If you switch the last two commands (add eth0 first), then both
will succeed.  If after that, you remove eth0 and try to re-add
it, it will fail!

It appears to be enough to simply check adj_list to keeps things
safe.

I've tried stacking multiple devices multiple times in all different
combinations, and either rx_handler registration prevented the stacking
of the device linking cought the error.

Signed-off-by: Vladislav Yasevich 
Acked-by: Jiri Pirko 
Acked-by: Veaceslav Falico 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

ipv6: protect skb->sk accesses from recursive dereference inside the stack

2015-04-29T08:31:46+00:00

[ Upstream commit f60e5990d9c1424af9dbca60a23ba2a1c7c1ce90 ]

We should not consult skb->sk for output decisions in xmit recursion
levels > 0 in the stack. Otherwise local socket settings could influence
the result of e.g. tunnel encapsulation process.

ipv6 does not conform with this in three places:

1) ip6_fragment: we do consult ipv6_npinfo for frag_size

2) sk_mc_loop in ipv6 uses skb->sk and checks if we should
   loop the packet back to the local socket

3) ip6_skb_dst_mtu could query the settings from the user socket and
   force a wrong MTU

Furthermore:
In sk_mc_loop we could potentially land in WARN_ON(1) if we use a
PF_PACKET socket ontop of an IPv6-backed vxlan device.

Reuse xmit_recursion as we are currently only interested in protecting
tunnel devices.

Cc: Jiri Pirko 
Signed-off-by: Hannes Frederic Sowa 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net: reject creation of netdev names with colons

2015-03-18T12:31:22+00:00

[ Upstream commit a4176a9391868bfa87705bcd2e3b49e9b9dd2996 ]

colons are used as a separator in netdev device lookup in dev_ioctl.c

Specific functions are SIOCGIFTXQLEN SIOCETHTOOL SIOCSIFNAME

Signed-off-by: Matthew Thode 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net: rps: fix cpu unplug

2015-02-27T01:50:10+00:00

[ Upstream commit ac64da0b83d82abe62f78b3d0e21cca31aea24fa ]

softnet_data.input_pkt_queue is protected by a spinlock that
we must hold when transferring packets from victim queue to an active
one. This is because other cpus could still be trying to enqueue packets
into victim queue.

A second problem is that when we transfert the NAPI poll_list from
victim to current cpu, we absolutely need to special case the percpu
backlog, because we do not want to add complex locking to protect
process_queue : Only owner cpu is allowed to manipulate it, unless cpu
is offline.

Based on initial patch from Prasad Sodagudi & Subash Abhinov
Kasiviswanathan.

This version is better because we do not slow down packet processing,
only make migration safer.

Reported-by: Prasad Sodagudi 
Reported-by: Subash Abhinov Kasiviswanathan 
Signed-off-by: Eric Dumazet 
Cc: Tom Herbert 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net: fix creation adjacent device symlinks

2015-01-27T16:18:59+00:00

commit 7ce64c79c4decdeb1afe0bf2f6ef834b382871d1 upstream.

__netdev_adjacent_dev_insert may add adjust device of different net
namespace, without proper check it leads to emergence of broken
sysfs links from/to devices in another namespace.
Fix: rewrite netdev_adjacent_is_neigh_list macro as a function,
     move net_eq check into netdev_adjacent_is_neigh_list.
     (thanks David)
     related to: 4c75431ac3520631f1d9e74aa88407e6374dbbc4

Signed-off-by: Alexander Fomichev 
Signed-off-by: David S. Miller 
Cc: Miquel van Smoorenburg 
Signed-off-by: Greg Kroah-Hartman

net: prevent of emerging cross-namespace symlinks

2015-01-27T16:18:59+00:00

commit 4c75431ac3520631f1d9e74aa88407e6374dbbc4 upstream.

Code manipulating sysfs symlinks on adjacent net_devices(s)
currently doesn't take into account that devices potentially
belong to different namespaces.

This patch trying to fix an issue as follows:
- check for net_ns before creating / deleting symlink.
  for now only netdev_adjacent_rename_links and
  __netdev_adjacent_dev_remove are affected, afaics
  __netdev_adjacent_dev_insert implies both net_devs
  belong to the same namespace.
- Drop all existing symlinks to / from all adj_devs before
  switching namespace and recreate them just after.

Signed-off-by: Alexander Y. Fomichev 
Signed-off-by: David S. Miller 
Cc: Miquel van Smoorenburg 
Signed-off-by: Greg Kroah-Hartman

net/core: Handle csum for CHECKSUM_COMPLETE VXLAN forwarding

2015-01-27T16:18:53+00:00

[ Upstream commit 2c26d34bbcc0b3f30385d5587aa232289e2eed8e ]

When using VXLAN tunnels and a sky2 device, I have experienced
checksum failures of the following type:

[ 4297.761899] eth0: hw csum failure
[...]
[ 4297.765223] Call Trace:
[ 4297.765224]    [] dump_stack+0x46/0x58
[ 4297.765235]  [] netdev_rx_csum_fault+0x42/0x50
[ 4297.765238]  [] ? skb_push+0x40/0x40
[ 4297.765240]  [] __skb_checksum_complete+0xbc/0xd0
[ 4297.765243]  [] tcp_v4_rcv+0x2e2/0x950
[ 4297.765246]  [] ? ip_rcv_finish+0x360/0x360

	These are reliably reproduced in a network topology of:

container:eth0 == host(OVS VXLAN on VLAN) == bond0 == eth0 (sky2) -> switch

	When VXLAN encapsulated traffic is received from a similarly
configured peer, the above warning is generated in the receive
processing of the encapsulated packet.  Note that the warning is
associated with the container eth0.

        The skbs from sky2 have ip_summed set to CHECKSUM_COMPLETE, and
because the packet is an encapsulated Ethernet frame, the checksum
generated by the hardware includes the inner protocol and Ethernet
headers.

	The receive code is careful to update the skb->csum, except in
__dev_forward_skb, as called by dev_forward_skb.  __dev_forward_skb
calls eth_type_trans, which in turn calls skb_pull_inline(skb, ETH_HLEN)
to skip over the Ethernet header, but does not update skb->csum when
doing so.

	This patch resolves the problem by adding a call to
skb_postpull_rcsum to update the skb->csum after the call to
eth_type_trans.

Signed-off-by: Jay Vosburgh 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman