linux-toradex.git/net/ipv4/ip_output.c, branch v4.4.85

net: account for current skb length when deciding about UFO

2017-08-13T02:29:09+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 
Signed-off-by: Greg Kroah-Hartman

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

2017-08-13T02:29:09+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 
Signed-off-by: Greg Kroah-Hartman

udp: consistently apply ufo or fragmentation

2017-08-13T02:29:09+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"

2017-08-13T02:29:09+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"

2017-08-13T02:29:09+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

2017-08-11T16:08:59+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

2017-08-11T16:08:59+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

ipv4: Set skb->protocol properly for local output

2016-12-10T18:07:26+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 
Signed-off-by: Greg Kroah-Hartman

ipv4: only create late gso-skb if skb is already set up with CHECKSUM_PARTIAL

2016-04-20T06:41:57+00:00

[ Upstream commit a8c4a2522a0808c5c2143612909717d1115c40cf ]

Otherwise we break the contract with GSO to only pass CHECKSUM_PARTIAL
skbs down. This can easily happen with UDP+IPv4 sockets with the first
MSG_MORE write smaller than the MTU, second write is a sendfile.

Returning -EOPNOTSUPP lets the callers fall back into normal sendmsg path,
were we calculate the checksum manually during copying.

Commit d749c9cbffd6 ("ipv4: no CHECKSUM_PARTIAL on MSG_MORE corked
sockets") started to exposes this bug.

Fixes: d749c9cbffd6 ("ipv4: no CHECKSUM_PARTIAL on MSG_MORE corked sockets")
Reported-by: Jiri Benc 
Cc: Jiri Benc 
Reported-by: Wakko Warner 
Cc: Wakko Warner 
Signed-off-by: Hannes Frederic Sowa 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net: preserve IP control block during GSO segmentation

2016-01-31T19:29:00+00:00

[ Upstream commit 9207f9d45b0ad071baa128e846d7e7ed85016df3 ]

Skb_gso_segment() uses skb control block during segmentation.
This patch adds 32-bytes room for previous control block which
will be copied into all resulting segments.

This patch fixes kernel crash during fragmenting forwarded packets.
Fragmentation requires valid IP CB in skb for clearing ip options.
Also patch removes custom save/restore in ovs code, now it's redundant.

Signed-off-by: Konstantin Khlebnikov 
Link: http://lkml.kernel.org/r/CALYGNiP-0MZ-FExV2HutTvE9U-QQtkKSoE--KN=JQE5STYsjAA@mail.gmail.com
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman