linux-toradex.git/net/ipv6, branch v3.12.45

udp: fix behavior of wrong checksums

2015-06-10T09:18:15+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: Jiri Slaby

ipv6: Don't reduce hop limit for an interface

2015-04-27T08:53:38+00:00

[ Upstream commit 6fd99094de2b83d1d4c8457f2c83483b2828e75a ]

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 
Signed-off-by: Jiri Slaby

tcp: prevent fetching dst twice in early demux code

2015-04-27T08:53:30+00:00

[ Upstream commit d0c294c53a771ae7e84506dfbd8c18c30f078735 ]

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 ACCESS_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 
Signed-off-by: Jiri Slaby

ipv6: reallocate addrconf router for ipv6 address when lo device up

2015-04-09T12:13:49+00:00

commit 33d99113b1102c2d2f8603b9ba72d89d915c13f5 upstream.

commit 25fb6ca4ed9cad72f14f61629b68dc03c0d9713f
"net IPv6 : Fix broken IPv6 routing table after loopback down-up"
allocates addrconf router for ipv6 address when lo device up.
but commit a881ae1f625c599b460cc8f8a7fcb1c438f699ad
"ipv6:don't call addrconf_dst_alloc again when enable lo" breaks
this behavior.

Since the addrconf router is moved to the garbage list when
lo device down, we should release this router and rellocate
a new one for ipv6 address when lo device up.

This patch solves bug 67951 on bugzilla
https://bugzilla.kernel.org/show_bug.cgi?id=67951

change from v1:
use ip6_rt_put to repleace ip6_del_rt, thanks Hannes!
change code style, suggested by Sergei.

CC: Sabrina Dubroca 
CC: Hannes Frederic Sowa 
Reported-by: Weilong Chen 
Signed-off-by: Weilong Chen 
Signed-off-by: Gao feng 
Acked-by: Hannes Frederic Sowa 
Signed-off-by: David S. Miller 
Signed-off-by: Jiri Slaby

ipv6: fix backtracking for throw routes

2015-04-09T11:13:46+00:00

[ Upstream commit 73ba57bfae4a1914f6a6dac71e3168dd900e00af ]

for throw routes to trigger evaluation of other policy rules
EAGAIN needs to be propagated up to fib_rules_lookup
similar to how its done for IPv4

A simple testcase for verification is:

ip -6 rule add lookup 33333 priority 33333
ip -6 route add throw 2001:db8::1
ip -6 route add 2001:db8::1 via fe80::1 dev wlan0 table 33333
ip route get 2001:db8::1

Signed-off-by: Steven Barth 
Signed-off-by: David S. Miller 
Signed-off-by: Jiri Slaby

net: ping: Return EAFNOSUPPORT when appropriate.

2015-03-12T09:06:29+00:00

[ Upstream commit 9145736d4862145684009d6a72a6e61324a9439e ]

1. For an IPv4 ping socket, ping_check_bind_addr does not check
   the family of the socket address that's passed in. Instead,
   make it behave like inet_bind, which enforces either that the
   address family is AF_INET, or that the family is AF_UNSPEC and
   the address is 0.0.0.0.
2. For an IPv6 ping socket, ping_check_bind_addr returns EINVAL
   if the socket family is not AF_INET6. Return EAFNOSUPPORT
   instead, for consistency with inet6_bind.
3. Make ping_v4_sendmsg and ping_v6_sendmsg return EAFNOSUPPORT
   instead of EINVAL if an incorrect socket address structure is
   passed in.
4. Make IPv6 ping sockets be IPv6-only. The code does not support
   IPv4, and it cannot easily be made to support IPv4 because
   the protocol numbers for ICMP and ICMPv6 are different. This
   makes connect(::ffff:192.0.2.1) fail with EAFNOSUPPORT instead
   of making the socket unusable.

Among other things, this fixes an oops that can be triggered by:

    int s = socket(AF_INET, SOCK_DGRAM, IPPROTO_ICMP);
    struct sockaddr_in6 sin6 = {
        .sin6_family = AF_INET6,
        .sin6_addr = in6addr_any,
    };
    bind(s, (struct sockaddr *) &sin6, sizeof(sin6));

Change-Id: If06ca86d9f1e4593c0d6df174caca3487c57a241
Signed-off-by: Lorenzo Colitti 
Signed-off-by: David S. Miller 
Signed-off-by: Jiri Slaby

udp: only allow UFO for packets from SOCK_DGRAM sockets

2015-03-12T09:06:28+00:00

[ Upstream commit acf8dd0a9d0b9e4cdb597c2f74802f79c699e802 ]

If an over-MTU UDP datagram is sent through a SOCK_RAW socket to a
UFO-capable device, ip_ufo_append_data() sets skb->ip_summed to
CHECKSUM_PARTIAL unconditionally as all GSO code assumes transport layer
checksum is to be computed on segmentation. However, in this case,
skb->csum_start and skb->csum_offset are never set as raw socket
transmit path bypasses udp_send_skb() where they are usually set. As a
result, driver may access invalid memory when trying to calculate the
checksum and store the result (as observed in virtio_net driver).

Moreover, the very idea of modifying the userspace provided UDP header
is IMHO against raw socket semantics (I wasn't able to find a document
clearly stating this or the opposite, though). And while allowing
CHECKSUM_NONE in the UFO case would be more efficient, it would be a bit
too intrusive change just to handle a corner case like this. Therefore
disallowing UFO for packets from SOCK_DGRAM seems to be the best option.

Signed-off-by: Michal Kubecek 
Signed-off-by: David S. Miller 
Signed-off-by: Jiri Slaby

ipv6: fix ipv6_cow_metrics for non DST_HOST case

2015-03-12T09:06:23+00:00

[ Upstream commit 3b4711757d7903ab6fa88a9e7ab8901b8227da60 ]

ipv6_cow_metrics() currently assumes only DST_HOST routes require
dynamic metrics allocation from inetpeer.  The assumption breaks
when ndisc discovered router with RTAX_MTU and RTAX_HOPLIMIT metric.
Refer to ndisc_router_discovery() in ndisc.c and note that dst_metric_set()
is called after the route is created.

This patch creates the metrics array (by calling dst_cow_metrics_generic) in
ipv6_cow_metrics().

Test:
radvd.conf:
interface qemubr0
{
	AdvLinkMTU 1300;
	AdvCurHopLimit 30;

	prefix fd00:face:face:face::/64
	{
		AdvOnLink on;
		AdvAutonomous on;
		AdvRouterAddr off;
	};
};

Before:
[root@qemu1 ~]# ip -6 r show | egrep -v unreachable
fd00:face:face:face::/64 dev eth0  proto kernel  metric 256  expires 27sec
fe80::/64 dev eth0  proto kernel  metric 256
default via fe80::74df:d0ff:fe23:8ef2 dev eth0  proto ra  metric 1024  expires 27sec

After:
[root@qemu1 ~]# ip -6 r show | egrep -v unreachable
fd00:face:face:face::/64 dev eth0  proto kernel  metric 256  expires 27sec mtu 1300
fe80::/64 dev eth0  proto kernel  metric 256  mtu 1300
default via fe80::74df:d0ff:fe23:8ef2 dev eth0  proto ra  metric 1024  expires 27sec mtu 1300 hoplimit 30

Fixes: 8e2ec639173f325 (ipv6: don't use inetpeer to store metrics for routes.)
Signed-off-by: Martin KaFai Lau 
Signed-off-by: David S. Miller 
Signed-off-by: Jiri Slaby

ipv6: replacing a rt6_info needs to purge possible propagated rt6_infos too

2015-02-10T10:16:50+00:00

[ Upstream commit 6e9e16e6143b725662e47026a1d0f270721cdd24 ]

Lubomir Rintel reported that during replacing a route the interface
reference counter isn't correctly decremented.

To quote bug :
| [root@rhel7-5 lkundrak]# sh -x lal
| + ip link add dev0 type dummy
| + ip link set dev0 up
| + ip link add dev1 type dummy
| + ip link set dev1 up
| + ip addr add 2001:db8:8086::2/64 dev dev0
| + ip route add 2001:db8:8086::/48 dev dev0 proto static metric 20
| + ip route add 2001:db8:8088::/48 dev dev1 proto static metric 10
| + ip route replace 2001:db8:8086::/48 dev dev1 proto static metric 20
| + ip link del dev0 type dummy
| Message from syslogd@rhel7-5 at Jan 23 10:54:41 ...
|  kernel:unregister_netdevice: waiting for dev0 to become free. Usage count = 2
|
| Message from syslogd@rhel7-5 at Jan 23 10:54:51 ...
|  kernel:unregister_netdevice: waiting for dev0 to become free. Usage count = 2

During replacement of a rt6_info we must walk all parent nodes and check
if the to be replaced rt6_info got propagated. If so, replace it with
an alive one.

Fixes: 4a287eba2de3957 ("IPv6 routing, NLM_F_* flag support: REPLACE and EXCL flags support, warn about missing CREATE flag")
Reported-by: Lubomir Rintel 
Signed-off-by: Hannes Frederic Sowa 
Tested-by: Lubomir Rintel 
Signed-off-by: David S. Miller 
Signed-off-by: Jiri Slaby

ipv6: stop sending PTB packets for MTU < 1280

2015-02-10T10:16:49+00:00

[ Upstream commit 9d289715eb5c252ae15bd547cb252ca547a3c4f2 ]

Reduce the attack vector and stop generating IPv6 Fragment Header for
paths with an MTU smaller than the minimum required IPv6 MTU
size (1280 byte) - called atomic fragments.

See IETF I-D "Deprecating the Generation of IPv6 Atomic Fragments" [1]
for more information and how this "feature" can be misused.

[1] https://tools.ietf.org/html/draft-ietf-6man-deprecate-atomfrag-generation-00

Signed-off-by: Fernando Gont 
Signed-off-by: Hagen Paul Pfeifer 
Acked-by: Hannes Frederic Sowa 
Signed-off-by: David S. Miller 
Signed-off-by: Jiri Slaby