linux-toradex.git/net/ipv6, branch v3.2.57

net: ip, ipv6: handle gso skbs in forwarding path

2014-04-09T01:20:45+00:00

commit fe6cc55f3a9a053482a76f5a6b2257cee51b4663 upstream.

[ use zero netdev_feature mask to avoid backport of
  netif_skb_dev_features function ]

Marcelo Ricardo Leitner reported problems when the forwarding link path
has a lower mtu than the incoming one if the inbound interface supports GRO.

Given:
Host  R1  R2

Host sends tcp stream which is routed via R1 and R2.  R1 performs GRO.

In this case, the kernel will fail to send ICMP fragmentation needed
messages (or pkt too big for ipv6), as GSO packets currently bypass dstmtu
checks in forward path. Instead, Linux tries to send out packets exceeding
the mtu.

When locking route MTU on Host (i.e., no ipv4 DF bit set), R1 does
not fragment the packets when forwarding, and again tries to send out
packets exceeding R1-R2 link mtu.

This alters the forwarding dstmtu checks to take the individual gso
segment lengths into account.

For ipv6, we send out pkt too big error for gso if the individual
segments are too big.

For ipv4, we either send icmp fragmentation needed, or, if the DF bit
is not set, perform software segmentation and let the output path
create fragments when the packet is leaving the machine.
It is not 100% correct as the error message will contain the headers of
the GRO skb instead of the original/segmented one, but it seems to
work fine in my (limited) tests.

Eric Dumazet suggested to simply shrink mss via ->gso_size to avoid
sofware segmentation.

However it turns out that skb_segment() assumes skb nr_frags is related
to mss size so we would BUG there.  I don't want to mess with it considering
Herbert and Eric disagree on what the correct behavior should be.

Hannes Frederic Sowa notes that when we would shrink gso_size
skb_segment would then also need to deal with the case where
SKB_MAX_FRAGS would be exceeded.

This uses sofware segmentation in the forward path when we hit ipv4
non-DF packets and the outgoing link mtu is too small.  Its not perfect,
but given the lack of bug reports wrt. GRO fwd being broken this is a
rare case anyway.  Also its not like this could not be improved later
once the dust settles.

Acked-by: Herbert Xu 
Reported-by: Marcelo Ricardo Leitner 
Signed-off-by: Florian Westphal 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

net: avoid reference counter overflows on fib_rules in multicast forwarding

2014-02-15T19:20:10+00:00

[ Upstream commit 95f4a45de1a0f172b35451fc52283290adb21f6e ]

Bob Falken reported that after 4G packets, multicast forwarding stopped
working. This was because of a rule reference counter overflow which
freed the rule as soon as the overflow happend.

This patch solves this by adding the FIB_LOOKUP_NOREF flag to
fib_rules_lookup calls. This is safe even from non-rcu locked sections
as in this case the flag only implies not taking a reference to the rule,
which we don't need at all.

Rules only hold references to the namespace, which are guaranteed to be
available during the call of the non-rcu protected function reg_vif_xmit
because of the interface reference which itself holds a reference to
the net namespace.

Fixes: f0ad0860d01e47 ("ipv4: ipmr: support multiple tables")
Fixes: d1db275dd3f6e4 ("ipv6: ip6mr: support multiple tables")
Reported-by: Bob Falken 
Cc: Patrick McHardy 
Cc: Thomas Graf 
Cc: Julian Anastasov 
Cc: Eric Dumazet 
Signed-off-by: Hannes Frederic Sowa 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

ipv6: don't count addrconf generated routes against gc limit

2014-02-15T19:20:08+00:00

[ Upstream commit a3300ef4bbb1f1e33ff0400e1e6cf7733d988f4f ]

Brett Ciphery reported that new ipv6 addresses failed to get installed
because the addrconf generated dsts where counted against the dst gc
limit. We don't need to count those routes like we currently don't count
administratively added routes.

Because the max_addresses check enforces a limit on unbounded address
generation first in case someone plays with router advertisments, we
are still safe here.

Reported-by: Brett Ciphery 
Signed-off-by: Hannes Frederic Sowa 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

ipv6: fix possible seqlock deadlock in ip6_finish_output2

2014-01-03T04:33:34+00:00

[ Upstream commit 7f88c6b23afbd31545c676dea77ba9593a1a14bf ]

IPv6 stats are 64 bits and thus are protected with a seqlock. By not
disabling bottom-half we could deadlock here if we don't disable bh and
a softirq reentrantly updates the same mib.

Cc: Eric Dumazet 
Signed-off-by: Hannes Frederic Sowa 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

ipv6: fix leaking uninitialized port number of offender sockaddr

2014-01-03T04:33:33+00:00

[ Upstream commit 1fa4c710b6fe7b0aac9907240291b6fe6aafc3b8 ]

Offenders don't have port numbers, so set it to 0.

Signed-off-by: Hannes Frederic Sowa 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

inet: fix addr_len/msg->msg_namelen assignment in recv_error and rxpmtu functions

2014-01-03T04:33:33+00:00

[ Upstream commit 85fbaa75037d0b6b786ff18658ddf0b4014ce2a4 ]

Commit bceaa90240b6019ed73b49965eac7d167610be69 ("inet: prevent leakage
of uninitialized memory to user in recv syscalls") conditionally updated
addr_len if the msg_name is written to. The recv_error and rxpmtu
functions relied on the recvmsg functions to set up addr_len before.

As this does not happen any more we have to pass addr_len to those
functions as well and set it to the size of the corresponding sockaddr
length.

This broke traceroute and such.

Fixes: bceaa90240b6 ("inet: prevent leakage of uninitialized memory to user in recv syscalls")
Reported-by: Brad Spengler 
Reported-by: Tom Labanowski
Cc: mpb 
Cc: David S. Miller 
Cc: Eric Dumazet 
Signed-off-by: Hannes Frederic Sowa 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

inet: prevent leakage of uninitialized memory to user in recv syscalls

2014-01-03T04:33:33+00:00

[ Upstream commit bceaa90240b6019ed73b49965eac7d167610be69 ]

Only update *addr_len when we actually fill in sockaddr, otherwise we
can return uninitialized memory from the stack to the caller in the
recvfrom, recvmmsg and recvmsg syscalls. Drop the the (addr_len == NULL)
checks because we only get called with a valid addr_len pointer either
from sock_common_recvmsg or inet_recvmsg.

If a blocking read waits on a socket which is concurrently shut down we
now return zero and set msg_msgnamelen to 0.

Reported-by: mpb 
Suggested-by: Eric Dumazet 
Signed-off-by: Hannes Frederic Sowa 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

ipv6: use rt6_get_dflt_router to get default router in rt6_route_rcv

2014-01-03T04:33:32+00:00

[ Upstream commit f104a567e673f382b09542a8dc3500aa689957b4 ]

As the rfc 4191 said, the Router Preference and Lifetime values in a
::/0 Route Information Option should override the preference and lifetime
values in the Router Advertisement header. But when the kernel deals with
a ::/0 Route Information Option, the rt6_get_route_info() always return
NULL, that means that overriding will not happen, because those default
routers were added without flag RTF_ROUTEINFO in rt6_add_dflt_router().

In order to deal with that condition, we should call rt6_get_dflt_router
when the prefix length is 0.

Signed-off-by: Duan Jiong 
Acked-by: Hannes Frederic Sowa 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

inet: fix possible memory corruption with UDP_CORK and UFO

2013-11-28T14:01:59+00:00

[ This is a simplified -stable version of a set of upstream commits. ]

This is a replacement patch only for stable which does fix the problems
handled by the following two commits in -net:

"ip_output: do skb ufo init for peeked non ufo skb as well" (e93b7d748be887cd7639b113ba7d7ef792a7efb9)
"ip6_output: do skb ufo init for peeked non ufo skb as well" (c547dbf55d5f8cf615ccc0e7265e98db27d3fb8b)

Three frames are written on a corked udp socket for which the output
netdevice has UFO enabled.  If the first and third frame are smaller than
the mtu and the second one is bigger, we enqueue the second frame with
skb_append_datato_frags without initializing the gso fields. This leads
to the third frame appended regulary and thus constructing an invalid skb.

This fixes the problem by always using skb_append_datato_frags as soon
as the first frag got enqueued to the skb without marking the packet
as SKB_GSO_UDP.

The problem with only two frames for ipv6 was fixed by "ipv6: udp
packets following an UFO enqueued packet need also be handled by UFO"
(2811ebac2521ceac84f2bdae402455baa6a7fb47).

Cc: Jiri Pirko 
Cc: Eric Dumazet 
Cc: David Miller 
Signed-off-by: Hannes Frederic Sowa 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Ben Hutchings

ipv6: restrict neighbor entry creation to output flow

2013-11-28T14:01:56+00:00

This patch is based on 3.2.y branch, the one used by reporter. Please let me
know if it should be different. Thanks.

The patch which introduced the regression was applied on stables:
3.0.64 3.4.31 3.7.8 3.2.39

The patch which introduced the regression was for stable trees only.

---8<---

Commit 0d6a77079c475033cb622c07c5a880b392ef664e "ipv6: do not create
neighbor entries for local delivery" introduced a regression on
which routes to local delivery would not work anymore. Like this:

    $ ip -6 route add local 2001::/64 dev lo
    $ ping6 -c1 2001::9
    PING 2001::9(2001::9) 56 data bytes
    ping: sendmsg: Invalid argument

As this is a local delivery, that commit would not allow the creation of a
neighbor entry and thus the packet cannot be sent.

But as TPROXY scenario actually needs to avoid the neighbor entry creation only
for input flow, this patch now limits previous patch to input flow, keeping
output as before that patch.

Reported-by: Debabrata Banerjee 
Signed-off-by: Marcelo Ricardo Leitner 
Signed-off-by: Jiri Pirko 
Acked-by: Hannes Frederic Sowa 
CC: Hannes Frederic Sowa 
Signed-off-by: Ben Hutchings