linux-toradex.git/net/ipv4/ip_output.c, branch v4.9.101

udp: consistently apply ufo or fragmentation

2017-08-13T02:31:22+00:00

[ Upstream commit 85f1bd9a7b5a79d5baa8bf44af19658f7bf77bfa ]

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

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

2017-08-13T02:31:22+00:00

This reverts commit f102bb7164c9020e12662998f0fd99c3be72d4f6 which is
commit 0a28cfd51e17f4f0a056bcf66bfbe492c3b99f38 upstream as there is
another patch that needs to be applied instead of this one.

Cc: Zheng Li 
Cc: David S. Miller 
Cc: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

revert "net: account for current skb length when deciding about UFO"

2017-08-13T02:31:22+00:00

This reverts commit ef09c9ff343122a0b245416066992d096416ff19 which is
commit a5cb659bbc1c8644efa0c3138a757a1e432a4880 upstream as it causes
merge issues with later patches that are much more important...

Cc: Michal Kubecek 
Cc: Vlad Yasevich 
Cc: David S. Miller 
Cc: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

net: account for current skb length when deciding about UFO

2017-08-11T15:49:37+00:00

[ Upstream commit a5cb659bbc1c8644efa0c3138a757a1e432a4880 ]

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 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

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

2017-08-11T15:49:37+00:00

[ Upstream commit 0a28cfd51e17f4f0a056bcf66bfbe492c3b99f38 ]

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 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

tcp: fix mark propagation with fwmark_reflect enabled

2017-02-18T14:11:43+00:00

commit bf99b4ded5f8a4767dbb9d180626f06c51f9881f upstream.

Otherwise, RST packets generated by the TCP stack for non-existing
sockets always have mark 0.
The mark from the original packet is assigned to the netns_ipv4/6
socket used to send the response so that it can get copied into the
response skb when the socket sends it.

Fixes: e110861f8609 ("net: add a sysctl to reflect the fwmark on replies")
Cc: Lorenzo Colitti 
Signed-off-by: Pau Espin Pedrol 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Greg Kroah-Hartman

ipv4: Set skb->protocol properly for local output

2016-12-02T17:34:22+00:00

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.

Cc: stable@vger.kernel.org
Signed-off-by: Eli Cooper 
Signed-off-by: David S. Miller

ipv4: update comment to document GSO fragmentation cases.

2016-11-10T17:01:54+00:00

This is a follow-up to commit 9ee6c5dc816a ("ipv4: allow local
fragmentation in ip_finish_output_gso()"), updating the comment
documenting cases in which fragmentation is needed for egress
GSO packets.

Suggested-by: Shmulik Ladkani 
Reviewed-by: Shmulik Ladkani 
Signed-off-by: Lance Richardson 
Signed-off-by: David S. Miller

net: tcp response should set oif only if it is L3 master

2016-11-10T03:32:10+00:00

Lorenzo noted an Android unit test failed due to e0d56fdd7342:
"The expectation in the test was that the RST replying to a SYN sent to a
closed port should be generated with oif=0. In other words it should not
prefer the interface where the SYN came in on, but instead should follow
whatever the routing table says it should do."

Revert the change to ip_send_unicast_reply and tcp_v6_send_response such
that the oif in the flow is set to the skb_iif only if skb_iif is an L3
master.

Fixes: e0d56fdd7342 ("net: l3mdev: remove redundant calls")
Reported-by: Lorenzo Colitti 
Signed-off-by: David Ahern 
Tested-by: Lorenzo Colitti 
Acked-by: Lorenzo Colitti 
Signed-off-by: David S. Miller

ipv4: allow local fragmentation in ip_finish_output_gso()

2016-11-03T20:10:26+00:00

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