linux-stable.git/net/packet, branch v4.4.52

packet: Do not call fanout_release from atomic contexts

2017-02-26T10:07:50+00:00

[ Upstream commit 2bd624b4611ffee36422782d16e1c944d1351e98 ]

Commit 6664498280cf ("packet: call fanout_release, while UNREGISTERING a
netdev"), unfortunately, introduced the following issues.

1. calling mutex_lock(&fanout_mutex) (fanout_release()) from inside
rcu_read-side critical section. rcu_read_lock disables preemption, most often,
which prohibits calling sleeping functions.

[  ] include/linux/rcupdate.h:560 Illegal context switch in RCU read-side critical section!
[  ]
[  ] rcu_scheduler_active = 1, debug_locks = 0
[  ] 4 locks held by ovs-vswitchd/1969:
[  ]  #0:  (cb_lock){++++++}, at: [] genl_rcv+0x19/0x40
[  ]  #1:  (ovs_mutex){+.+.+.}, at: [] ovs_vport_cmd_del+0x4a/0x100 [openvswitch]
[  ]  #2:  (rtnl_mutex){+.+.+.}, at: [] rtnl_lock+0x17/0x20
[  ]  #3:  (rcu_read_lock){......}, at: [] packet_notifier+0x5/0x3f0
[  ]
[  ] Call Trace:
[  ]  [] dump_stack+0x85/0xc4
[  ]  [] lockdep_rcu_suspicious+0x107/0x110
[  ]  [] ___might_sleep+0x57/0x210
[  ]  [] __might_sleep+0x70/0x90
[  ]  [] mutex_lock_nested+0x3c/0x3a0
[  ]  [] ? vprintk_default+0x1f/0x30
[  ]  [] ? printk+0x4d/0x4f
[  ]  [] fanout_release+0x1d/0xe0
[  ]  [] packet_notifier+0x2f9/0x3f0

2. calling mutex_lock(&fanout_mutex) inside spin_lock(&po->bind_lock).
"sleeping function called from invalid context"

[  ] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:620
[  ] in_atomic(): 1, irqs_disabled(): 0, pid: 1969, name: ovs-vswitchd
[  ] INFO: lockdep is turned off.
[  ] Call Trace:
[  ]  [] dump_stack+0x85/0xc4
[  ]  [] ___might_sleep+0x202/0x210
[  ]  [] __might_sleep+0x70/0x90
[  ]  [] mutex_lock_nested+0x3c/0x3a0
[  ]  [] fanout_release+0x1d/0xe0
[  ]  [] packet_notifier+0x2f9/0x3f0

3. calling dev_remove_pack(&fanout->prot_hook), from inside
spin_lock(&po->bind_lock) or rcu_read-side critical-section. dev_remove_pack()
-> synchronize_net(), which might sleep.

[  ] BUG: scheduling while atomic: ovs-vswitchd/1969/0x00000002
[  ] INFO: lockdep is turned off.
[  ] Call Trace:
[  ]  [] dump_stack+0x85/0xc4
[  ]  [] __schedule_bug+0x64/0x73
[  ]  [] __schedule+0x6b/0xd10
[  ]  [] schedule+0x6b/0x80
[  ]  [] schedule_timeout+0x38d/0x410
[  ]  [] synchronize_sched_expedited+0x53d/0x810
[  ]  [] synchronize_rcu_expedited+0xe/0x10
[  ]  [] synchronize_net+0x35/0x50
[  ]  [] dev_remove_pack+0x13/0x20
[  ]  [] fanout_release+0xbe/0xe0
[  ]  [] packet_notifier+0x2f9/0x3f0

4. fanout_release() races with calls from different CPU.

To fix the above problems, remove the call to fanout_release() under
rcu_read_lock(). Instead, call __dev_remove_pack(&fanout->prot_hook) and
netdev_run_todo will be happy that &dev->ptype_specific list is empty. In order
to achieve this, I moved dev_{add,remove}_pack() out of fanout_{add,release} to
__fanout_{link,unlink}. So, call to {,__}unregister_prot_hook() will make sure
fanout->prot_hook is removed as well.

Fixes: 6664498280cf ("packet: call fanout_release, while UNREGISTERING a netdev")
Reported-by: Eric Dumazet 
Signed-off-by: Anoob Soman 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

packet: fix races in fanout_add()

2017-02-26T10:07:49+00:00

[ Upstream commit d199fab63c11998a602205f7ee7ff7c05c97164b ]

Multiple threads can call fanout_add() at the same time.

We need to grab fanout_mutex earlier to avoid races that could
lead to one thread freeing po->rollover that was set by another thread.

Do the same in fanout_release(), for peace of mind, and to help us
finding lockdep issues earlier.

Fixes: dc99f600698d ("packet: Add fanout support.")
Fixes: 0648ab70afe6 ("packet: rollover prepare: per-socket state")
Signed-off-by: Eric Dumazet 
Cc: Willem de Bruijn 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

packet: round up linear to header len

2017-02-18T15:39:27+00:00

[ Upstream commit 57031eb794906eea4e1c7b31dc1e2429c0af0c66 ]

Link layer protocols may unconditionally pull headers, as Ethernet
does in eth_type_trans. Ensure that the entire link layer header
always lies in the skb linear segment. tpacket_snd has such a check.
Extend this to packet_snd.

Variable length link layer headers complicate the computation
somewhat. Here skb->len may be smaller than dev->hard_header_len.

Round up the linear length to be at least as long as the smallest of
the two.

Reported-by: Dmitry Vyukov 
Signed-off-by: Willem de Bruijn 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

packet: fix race condition in packet_set_ring

2016-12-10T18:07:24+00:00

[ Upstream commit 84ac7260236a49c79eede91617700174c2c19b0c ]

When packet_set_ring creates a ring buffer it will initialize a
struct timer_list if the packet version is TPACKET_V3. This value
can then be raced by a different thread calling setsockopt to
set the version to TPACKET_V1 before packet_set_ring has finished.

This leads to a use-after-free on a function pointer in the
struct timer_list when the socket is closed as the previously
initialized timer will not be deleted.

The bug is fixed by taking lock_sock(sk) in packet_setsockopt when
changing the packet version while also taking the lock at the start
of packet_set_ring.

Fixes: f6fb8f100b80 ("af-packet: TPACKET_V3 flexible buffer implementation.")
Signed-off-by: Philip Pettersson 
Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

packet: on direct_xmit, limit tso and csum to supported devices

2016-11-15T06:46:39+00:00

[ Upstream commit 104ba78c98808ae837d1f63aae58c183db5505df ]

When transmitting on a packet socket with PACKET_VNET_HDR and
PACKET_QDISC_BYPASS, validate device support for features requested
in vnet_hdr.

Drop TSO packets sent to devices that do not support TSO or have the
feature disabled. Note that the latter currently do process those
packets correctly, regardless of not advertising the feature.

Because of SKB_GSO_DODGY, it is not sufficient to test device features
with netif_needs_gso. Full validate_xmit_skb is needed.

Switch to software checksum for non-TSO packets that request checksum
offload if that device feature is unsupported or disabled. Note that
similar to the TSO case, device drivers may perform checksum offload
correctly even when not advertising it.

When switching to software checksum, packets hit skb_checksum_help,
which has two BUG_ON checksum not in linear segment. Packet sockets
always allocate at least up to csum_start + csum_off + 2 as linear.

Tested by running github.com/wdebruij/kerneltools/psock_txring_vnet.c

  ethtool -K eth0 tso off tx on
  psock_txring_vnet -d $dst -s $src -i eth0 -l 2000 -n 1 -q -v
  psock_txring_vnet -d $dst -s $src -i eth0 -l 2000 -n 1 -q -v -N

  ethtool -K eth0 tx off
  psock_txring_vnet -d $dst -s $src -i eth0 -l 1000 -n 1 -q -v -G
  psock_txring_vnet -d $dst -s $src -i eth0 -l 1000 -n 1 -q -v -G -N

v2:
  - add EXPORT_SYMBOL_GPL(validate_xmit_skb_list)

Fixes: d346a3fae3ff ("packet: introduce PACKET_QDISC_BYPASS socket option")
Signed-off-by: Willem de Bruijn 
Acked-by: Eric Dumazet 
Acked-by: Daniel Borkmann 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

packet: call fanout_release, while UNREGISTERING a netdev

2016-11-15T06:46:37+00:00

[ Upstream commit 6664498280cf17a59c3e7cf1a931444c02633ed1 ]

If a socket has FANOUT sockopt set, a new proto_hook is registered
as part of fanout_add(). When processing a NETDEV_UNREGISTER event in
af_packet, __fanout_unlink is called for all sockets, but prot_hook which was
registered as part of fanout_add is not removed. Call fanout_release, on a
NETDEV_UNREGISTER, which removes prot_hook and removes fanout from the
fanout_list.

This fixes BUG_ON(!list_empty(&dev->ptype_specific)) in netdev_run_todo()

Signed-off-by: Anoob Soman 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

packet: Use symmetric hash for PACKET_FANOUT_HASH.

2016-07-27T16:47:31+00:00

[ Upstream commit eb70db8756717b90c01ccc765fdefc4dd969fc74 ]

People who use PACKET_FANOUT_HASH want a symmetric hash, meaning that
they want packets going in both directions on a flow to hash to the
same bucket.

The core kernel SKB hash became non-symmetric when the ipv6 flow label
and other entities were incorporated into the standard flow hash order
to increase entropy.

But there are no users of PACKET_FANOUT_HASH who want an assymetric
hash, they all want a symmetric one.

Therefore, use the flow dissector to compute a flat symmetric hash
over only the protocol, addresses and ports.  This hash does not get
installed into and override the normal skb hash, so this change has
no effect whatsoever on the rest of the stack.

Reported-by: Eric Leblond 
Tested-by: Eric Leblond 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

packet: fix heap info leak in PACKET_DIAG_MCLIST sock_diag interface

2016-05-19T00:06:35+00:00

[ Upstream commit 309cf37fe2a781279b7675d4bb7173198e532867 ]

Because we miss to wipe the remainder of i->addr[] in packet_mc_add(),
pdiag_put_mclist() leaks uninitialized heap bytes via the
PACKET_DIAG_MCLIST netlink attribute.

Fix this by explicitly memset(0)ing the remaining bytes in i->addr[].

Fixes: eea68e2f1a00 ("packet: Report socket mclist info via diag module")
Signed-off-by: Mathias Krause 
Cc: Eric W. Biederman 
Cc: Pavel Emelyanov 
Acked-by: Pavel Emelyanov 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

packet: validate variable length ll headers

2016-04-20T06:42:01+00:00

[ Upstream commit 9ed988cd591500c040b2a6257bc68543e08ceeef ]

Replace link layer header validation check ll_header_truncate with
more generic dev_validate_header.

Validation based on hard_header_len incorrectly drops valid packets
in variable length protocols, such as AX25. dev_validate_header
calls header_ops.validate for such protocols to ensure correctness
below hard_header_len.

See also http://comments.gmane.org/gmane.linux.network/401064

Fixes 9c7077622dd9 ("packet: make packet_snd fail on len smaller than l2 header")
Signed-off-by: Willem de Bruijn 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

packet: Allow packets with only a header (but no payload)

2015-11-30T03:17:17+00:00

Commit 9c7077622dd91 ("packet: make packet_snd fail on len smaller
than l2 header") added validation for the packet size in packet_snd.
This change enforces that every packet needs a header (with at least
hard_header_len bytes) plus a payload with at least one byte. Before
this change the payload was optional.

This fixes PPPoE connections which do not have a "Service" or
"Host-Uniq" configured (which is violating the spec, but is still
widely used in real-world setups). Those are currently failing with the
following message: "pppd: packet size is too short (24 <= 24)"

Signed-off-by: Martin Blumenstingl 
Signed-off-by: David S. Miller