linux-stable.git/net/ipv6, branch v4.0.7

udp: fix behavior of wrong checksums

2015-06-23T00:03:23+00:00

[ Upstream commit beb39db59d14990e401e235faf66a6b9b31240b0 ]

We have two problems in UDP stack related to bogus checksums :

1) We return -EAGAIN to application even if receive queue is not empty.
   This breaks applications using edge trigger epoll()

2) Under UDP flood, we can loop forever without yielding to other
   processes, potentially hanging the host, especially on non SMP.

This patch is an attempt to make things better.

We might in the future add extra support for rt applications
wanting to better control time spent doing a recv() in a hostile
environment. For example we could validate checksums before queuing
packets in socket receive queue.

Signed-off-by: Eric Dumazet 
Cc: Willem de Bruijn 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net/ipv6/udp: Fix ipv6 multicast socket filter regression

2015-06-23T00:03:20+00:00

[ Upstream commit 33b4b015e1a1ca7a8fdce40af5e71642a8ea355c ]

Commit <5cf3d46192fc> ("udp: Simplify__udp*_lib_mcast_deliver")
simplified the filter for incoming IPv6 multicast but removed
the check of the local socket address and the UDP destination
address.

This patch restores the filter to prevent sockets bound to a IPv6
multicast IP to receive other UDP traffic link unicast.

Signed-off-by: Henning Rogge 
Fixes: 5cf3d46192fc ("udp: Simplify__udp*_lib_mcast_deliver")
Cc: "David S. Miller" 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

tcp/ipv6: fix flow label setting in TIME_WAIT state

2015-06-23T00:03:20+00:00

[ Upstream commit 21858cd02dabcf290564cbf4769b101eba54d7bb ]

commit 1d13a96c74fc ("ipv6: tcp: fix flowlabel value in ACK messages
send from TIME_WAIT") added the flow label in the last TCP packets.
Unfortunately, it was not casted properly.

This patch replace the buggy shift with be32_to_cpu/cpu_to_be32.

Fixes: 1d13a96c74fc ("ipv6: tcp: fix flowlabel value in ACK messages")
Reported-by: Eric Dumazet 
Signed-off-by: Florent Fourcot 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

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

2015-04-06T20:12:49+00:00

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

ip6mr: call del_timer_sync() in ip6mr_free_table()

2015-04-03T00:52:35+00:00

We need to wait for the flying timers, since we
are going to free the mrtable right after it.

Cc: Hannes Frederic Sowa 
Signed-off-by: Cong Wang 
Signed-off-by: David S. Miller

net: move fib_rules_unregister() under rtnl lock

2015-04-03T00:52:34+00:00

We have to hold rtnl lock for fib_rules_unregister()
otherwise the following race could happen:

fib_rules_unregister():	fib_nl_delrule():
...				...
...				ops = lookup_rules_ops();
list_del_rcu(&ops->list);
				list_for_each_entry(ops->rules) {
fib_rules_cleanup_ops(ops);	  ...
  list_del_rcu();		  list_del_rcu();
				}

Note, net->rules_mod_lock is actually not needed at all,
either upper layer netns code or rtnl lock guarantees
we are safe.

Cc: Alexander Duyck 
Cc: Thomas Graf 
Signed-off-by: Cong Wang 
Signed-off-by: David S. Miller

net: tcp6: fix double call of tcp_v6_fill_cb()

2015-03-29T20:36:05+00:00

tcp_v6_fill_cb() will be called twice if socket's state changes from
TCP_TIME_WAIT to TCP_LISTEN. That can result in control buffer data
corruption because in the second tcp_v6_fill_cb() call it's not copying
IP6CB(skb) anymore, but 'seq', 'end_seq', etc., so we can get weird and
unpredictable results. Performance loss of up to 1200% has been observed
in LTP/vxlan03 test.

This can be fixed by copying inet6_skb_parm to the beginning of 'cb'
only if xfrm6_policy_check() and tcp_v6_fill_cb() are going to be
called again.

Fixes: 2dc49d1680b53 ("tcp6: don't move IP6CB before xfrm6_policy_check()")

Signed-off-by: Alexey Kodanev 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller

ipmr,ip6mr: call ip6mr_free_table() on failure path

2015-03-29T19:13:54+00:00

Signed-off-by: Cong Wang 
Signed-off-by: David S. Miller

ipv6: Don't reduce hop limit for an interface

2015-03-25T15:41:08+00:00

A local route may have a lower hop_limit set than global routes do.

RFC 3756, Section 4.2.7, "Parameter Spoofing"

>   1.  The attacker includes a Current Hop Limit of one or another small
>       number which the attacker knows will cause legitimate packets to
>       be dropped before they reach their destination.

>   As an example, one possible approach to mitigate this threat is to
>   ignore very small hop limits.  The nodes could implement a
>   configurable minimum hop limit, and ignore attempts to set it below
>   said limit.

Signed-off-by: D.S. Ljungmark 
Acked-by: Hannes Frederic Sowa 
Signed-off-by: David S. Miller

tcp: prevent fetching dst twice in early demux code

2015-03-24T02:38:24+00:00

On s390x, gcc 4.8 compiles this part of tcp_v6_early_demux()

        struct dst_entry *dst = sk->sk_rx_dst;

        if (dst)
                dst = dst_check(dst, inet6_sk(sk)->rx_dst_cookie);

to code reading sk->sk_rx_dst twice, once for the test and once for
the argument of ip6_dst_check() (dst_check() is inline). This allows
ip6_dst_check() to be called with null first argument, causing a crash.

Protect sk->sk_rx_dst access by READ_ONCE() both in IPv4 and IPv6
TCP early demux code.

Fixes: 41063e9dd119 ("ipv4: Early TCP socket demux.")
Fixes: c7109986db3c ("ipv6: Early TCP socket demux")
Signed-off-by: Michal Kubecek 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller