linux-stable.git/net/ipv4/ip_output.c, branch v3.16.76

ipv4: hash net ptr into fragmentation bucket selection

2019-08-13T11:39:30+00:00

commit b6a7719aedd7e5c0f2df7641aa47386111682df4 upstream.

As namespaces are sometimes used with overlapping ip address ranges,
we should also use the namespace as input to the hash to select the ip
fragmentation counter bucket.

Cc: Eric Dumazet 
Cc: Flavio Leitner 
Signed-off-by: Hannes Frederic Sowa 
Signed-off-by: David S. Miller 
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings

net: test tailroom before appending to linear skb

2018-10-21T07:46:13+00:00

commit 113f99c3358564a0647d444c2ae34e8b1abfd5b9 upstream.

Device features may change during transmission. In particular with
corking, a device may toggle scatter-gather in between allocating
and writing to an skb.

Do not unconditionally assume that !NETIF_F_SG at write time implies
that the same held at alloc time and thus the skb has sufficient
tailroom.

This issue predates git history.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-by: Eric Dumazet 
Signed-off-by: Willem de Bruijn 
Reviewed-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

net: reflect mark on tcp syn ack packets

2017-10-12T14:28:01+00:00

commit e05a90ec9e1680952454ea9510da9a761a5baac9 upstream.

SYN-ACK responses on a server in response to a SYN from a client
did not get the injected skb mark that was tagged on the SYN packet.

Fixes: 84f39b08d786 ("net: support marking accepting TCP sockets")
Reviewed-by: Lorenzo Colitti 
Signed-off-by: Jamal Hadi Salim 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

net: account for current skb length when deciding about UFO

2017-09-15T17:30:15+00:00

commit a5cb659bbc1c8644efa0c3138a757a1e432a4880 upstream.

Our customer encountered stuck NFS writes for blocks starting at specific
offsets w.r.t. page boundary caused by networking stack sending packets via
UFO enabled device with wrong checksum. The problem can be reproduced by
composing a long UDP datagram from multiple parts using MSG_MORE flag:

  sendto(sd, buff, 1000, MSG_MORE, ...);
  sendto(sd, buff, 1000, MSG_MORE, ...);
  sendto(sd, buff, 3000, 0, ...);

Assume this packet is to be routed via a device with MTU 1500 and
NETIF_F_UFO enabled. When second sendto() gets into __ip_append_data(),
this condition is tested (among others) to decide whether to call
ip_ufo_append_data():

  ((length + fragheaderlen) > mtu) || (skb && skb_is_gso(skb))

At the moment, we already have skb with 1028 bytes of data which is not
marked for GSO so that the test is false (fragheaderlen is usually 20).
Thus we append second 1000 bytes to this skb without invoking UFO. Third
sendto(), however, has sufficient length to trigger the UFO path so that we
end up with non-UFO skb followed by a UFO one. Later on, udp_send_skb()
uses udp_csum() to calculate the checksum but that assumes all fragments
have correct checksum in skb->csum which is not true for UFO fragments.

When checking against MTU, we need to add skb->len to length of new segment
if we already have a partially filled skb and fragheaderlen only if there
isn't one.

In the IPv6 case, skb can only be null if this is the first segment so that
we have to use headersize (length of the first IPv6 header) rather than
fragheaderlen (length of IPv6 header of further fragments) for skb == NULL.

Fixes: e89e9cf539a2 ("[IPv4/IPv6]: UFO Scatter-gather approach")
Fixes: e4c5e13aa45c ("ipv6: Should use consistent conditional judgement for
	ip6 fragment between __ip6_append_data and ip6_finish_output")
Signed-off-by: Michal Kubecek 
Acked-by: Vlad Yasevich 
Signed-off-by: David S. Miller 
[bwh: Backported to 3.16:
 - Move headersize out of the if-statement in ip6_append_data() so it can be
   used for this
 - Adjust context to apply after "udp: consistently apply ufo or fragmentation"]
Signed-off-by: Ben Hutchings

ipv4: Should use consistent conditional judgement for ip fragment in __ip_append_data and ip_finish_output

2017-09-15T17:30:15+00:00

commit 0a28cfd51e17f4f0a056bcf66bfbe492c3b99f38 upstream.

There is an inconsistent conditional judgement in __ip_append_data and
ip_finish_output functions, the variable length in __ip_append_data just
include the length of application's payload and udp header, don't include
the length of ip header, but in ip_finish_output use
(skb->len > ip_skb_dst_mtu(skb)) as judgement, and skb->len include the
length of ip header.

That causes some particular application's udp payload whose length is
between (MTU - IP Header) and MTU were fragmented by ip_fragment even
though the rst->dev support UFO feature.

Add the length of ip header to length in __ip_append_data to keep
consistent conditional judgement as ip_finish_output for ip fragment.

Signed-off-by: Zheng Li 
Signed-off-by: David S. Miller 
[bwh: Backported to 3.16: adjust context to apply after "udp: consistently apply
 ufo or fragmentation"]
Signed-off-by: Ben Hutchings

udp: consistently apply ufo or fragmentation

2017-08-26T01:14:49+00:00

commit 85f1bd9a7b5a79d5baa8bf44af19658f7bf77bfa upstream.

When iteratively building a UDP datagram with MSG_MORE and that
datagram exceeds MTU, consistently choose UFO or fragmentation.

Once skb_is_gso, always apply ufo. Conversely, once a datagram is
split across multiple skbs, do not consider ufo.

Sendpage already maintains the first invariant, only add the second.
IPv6 does not have a sendpage implementation to modify.

A gso skb must have a partial checksum, do not follow sk_no_check_tx
in udp_send_skb.

Found by syzkaller.

Fixes: e89e9cf539a2 ("[IPv4/IPv6]: UFO Scatter-gather approach")
Reported-by: Andrey Konovalov 
Signed-off-by: Willem de Bruijn 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman 
[bwh: Backported to 3.16:
 - ip6_append_data() doesn't take a queue parameter; use &sk->sk_write_queue
 - Adjust context]
Signed-off-by: Ben Hutchings

udp: avoid ufo handling on IP payload compression packets

2017-07-18T17:40:10+00:00

commit 4b3b45edba9222e518a1ec72df841eba3609fe34 upstream.

commit c146066ab802 ("ipv4: Don't use ufo handling on later transformed
packets") and commit f89c56ce710a ("ipv6: Don't use ufo handling on
later transformed packets") added a check that 'rt->dst.header_len' isn't
zero in order to skip UFO, but it doesn't include IPcomp in transport mode
where it equals zero.

Packets, after payload compression, may not require further fragmentation,
and if original length exceeds MTU, later compressed packets will be
transmitted incorrectly. This can be reproduced with LTP udp_ipsec.sh test
on veth device with enabled UFO, MTU is 1500 and UDP payload is 2000:

* IPv4 case, offset is wrong + unnecessary fragmentation
    udp_ipsec.sh -p comp -m transport -s 2000 &
    tcpdump -ni ltp_ns_veth2
    ...
    IP (tos 0x0, ttl 64, id 45203, offset 0, flags [+],
      proto Compressed IP (108), length 49)
      10.0.0.2 > 10.0.0.1: IPComp(cpi=0x1000)
    IP (tos 0x0, ttl 64, id 45203, offset 1480, flags [none],
      proto UDP (17), length 21) 10.0.0.2 > 10.0.0.1: ip-proto-17

* IPv6 case, sending small fragments
    udp_ipsec.sh -6 -p comp -m transport -s 2000 &
    tcpdump -ni ltp_ns_veth2
    ...
    IP6 (flowlabel 0x6b9ba, hlim 64, next-header Compressed IP (108)
      payload length: 37) fd00::2 > fd00::1: IPComp(cpi=0x1000)
    IP6 (flowlabel 0x6b9ba, hlim 64, next-header Compressed IP (108)
      payload length: 21) fd00::2 > fd00::1: IPComp(cpi=0x1000)

Fix it by checking 'rt->dst.xfrm' pointer to 'xfrm_state' struct, skip UFO
if xfrm is set. So the new check will include both cases: IPcomp and IPsec.

Fixes: c146066ab802 ("ipv4: Don't use ufo handling on later transformed packets")
Fixes: f89c56ce710a ("ipv6: Don't use ufo handling on later transformed packets")
Signed-off-by: Alexey Kodanev 
Signed-off-by: David S. Miller 
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings

ipv4: Set skb->protocol properly for local output

2017-02-23T03:54:41+00:00

commit f4180439109aa720774baafdd798b3234ab1a0d2 upstream.

When xfrm is applied to TSO/GSO packets, it follows this path:

    xfrm_output() -> xfrm_output_gso() -> skb_gso_segment()

where skb_gso_segment() relies on skb->protocol to function properly.

This patch sets skb->protocol to ETH_P_IP before dst_output() is called,
fixing a bug where GSO packets sent through a sit tunnel are dropped
when xfrm is involved.

Signed-off-by: Eli Cooper 
Signed-off-by: David S. Miller 
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings

ipv4: allow local fragmentation in ip_finish_output_gso()

2017-02-23T03:54:29+00:00

commit 9ee6c5dc816aa8256257f2cd4008a9291ec7e985 upstream.

Some configurations (e.g. geneve interface with default
MTU of 1500 over an ethernet interface with 1500 MTU) result
in the transmission of packets that exceed the configured MTU.
While this should be considered to be a "bad" configuration,
it is still allowed and should not result in the sending
of packets that exceed the configured MTU.

Fix by dropping the assumption in ip_finish_output_gso() that
locally originated gso packets will never need fragmentation.
Basic testing using iperf (observing CPU usage and bandwidth)
have shown no measurable performance impact for traffic not
requiring fragmentation.

Fixes: c7ba65d7b649 ("net: ip: push gso skb forwarding handling down the stack")
Reported-by: Jan Tluka 
Signed-off-by: Lance Richardson 
Acked-by: Hannes Frederic Sowa 
Signed-off-by: David S. Miller 
[bwh: Backported to 3.16: never had the IPSKB_FRAG_SEGS flag]
Signed-off-by: Ben Hutchings

ipv4: Fix ip_queue_xmit to pass sk into ip_local_out_sk

2015-12-13T17:49:31+00:00

commit 850dcc4d4dd7d5da5c1b2a780c5e649c3b649545 upstream.

After a packet has been encapsulated by a tunnel we should use the
tunnel sockets local multicast loopback flag to control if the
encapsulated packet should be locally loopback back.

Pass sk into ip_local_out_sk so that in the rare case we are dealing
with a tunneled packet whose tunnel destination address is a multicast
address the kernel properly decides to loopback this packet.

In practice I don't think this matters as ip_queue_xmit is used by
tcp, l2tp and sctp none of which I am aware of uses ip level
multicasting as they are all point to point communications protocols.
Let's fix this before someone uses ip_queue_xmit for a tunnel protocol
that does use multicast.

Fixes: aad88724c9d5 ("ipv4: add a sock pointer to dst->output() path.")
Fixes: b0270e91014d ("ipv4: add a sock pointer to ip_queue_xmit()")
Signed-off-by: "Eric W. Biederman" 
Signed-off-by: David S. Miller 
Signed-off-by: Luis Henriques