Validate gso_type during segmentation as SKB_GSO_DODGY sources
may pass packets where the gso_type does not match the contents.

Syzkaller was able to enter the SCTP gso handler with a packet of
gso_type SKB_GSO_TCPV4.

On entry of transport layer gso handlers, verify that the gso_type
matches the transport protocol.

Fixes: 90017acc ("sctp: Add GSO support")
Link: http://lkml.kernel.org/r/<001a1137452496ffc305617e5fe0@google.com>
Reported-by: syzbot+fee64147a25aecd48055@syzkaller.appspotmail.com
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Acked-by: NJason Wang <jasowang@redhat.com>
Reviewed-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

tcp_fastopen_create_child() is static and should not be exported.

tcp4_gso_segment() and tcp6_gso_segment() should be static.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The send_check logic was only interesting in cases of TCP offload and
UDP UFO where the checksum needed to be initialized to the pseudo
header checksum. Now we've moved that logic into the related
gso_segment functions so gso_send_check is no longer needed.
Signed-off-by: NTom Herbert <therbert@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In tcp_v[46]_gso_send_check the TCP checksum is initialized to the
pseudo header checksum using __tcp_v[46]_send_check. We can move this
logic into new tcp[46]_gso_segment functions to be done when
ip_summed != CHECKSUM_PARTIAL (ip_summed == CHECKSUM_PARTIAL should be
the common case, possibly always true when taking GSO path). After this
change tcp_v[46]_gso_send_check is no-op.
Signed-off-by: NTom Herbert <therbert@google.com>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In tcp[64]_gro_receive call skb_gro_checksum_validate to validate TCP
checksum in the gro context.
Signed-off-by: NTom Herbert <therbert@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fixed a bug that was introduced by my GRE-GRO patch
(bf5a755f net-gre-gro: Add GRE
support to the GRO stack) that breaks the forwarding path
because various GSO related fields were not set. The bug will
cause on the egress path either the GSO code to fail, or a
GRE-TSO capable (NETIF_F_GSO_GRE) NICs to choke. The following
fix has been tested for both cases.
Signed-off-by: NH.K. Jerry Chu <hkchu@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When GRE support was added in linux-3.14, CHECKSUM_COMPLETE handling
broke on GRE+IPv6 because we did not update/use the appropriate csum :

GRO layer is supposed to use/update NAPI_GRO_CB(skb)->csum instead of
skb->csum

Tested using a GRE tunnel and IPv6 traffic. GRO aggregation now happens
at the first level (ethernet device) instead of being done in gre
tunnel. Native IPv6+TCP is still properly aggregated.

Fixes: bf5a755f ("net-gre-gro: Add GRE support to the GRO stack")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: Jerry Chu <hkchu@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch modifies the GRO stack to avoid the use of "network_header"
and associated macros like ip_hdr() and ipv6_hdr() in order to allow
an arbitary number of IP hdrs (v4 or v6) to be used in the
encapsulation chain. This lays the foundation for various IP
tunneling support (IP-in-IP, GRE, VXLAN, SIT,...) to be added later.

With this patch, the GRO stack traversing now is mostly based on
skb_gro_offset rather than special hdr offsets saved in skb (e.g.,
skb->network_header). As a result all but the top layer (i.e., the
the transport layer) must have hdrs of the same length in order for
a pkt to be considered for aggregation. Therefore when adding a new
encap layer (e.g., for tunneling), one must check and skip flows
(e.g., by setting NAPI_GRO_CB(p)->same_flow to 0) that have a
different hdr length.

Note that unlike the network header, the transport header can and
will continue to be set by the GRO code since there will be at
most one "transport layer" in the encap chain.
Signed-off-by: NH.K. Jerry Chu <hkchu@google.com>
Suggested-by: NEric Dumazet <edumazet@google.com>
Reviewed-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch simplifies the checksum verification in tcpX_gro_receive
by reusing the CHECKSUM_COMPLETE code for CHECKSUM_NONE.  All it
does for CHECKSUM_NONE is compute the partial checksum and then
treat it as if it came from the hardware (CHECKSUM_COMPLETE).
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

Cheers,
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In some cases we may receive IP packets that are longer than
their stated lengths.  Such packets are never merged in GRO.
However, we may end up computing their checksums incorrectly
and end up allowing packets with a bogus checksum enter our
stack with the checksum status set as verified.

Since such packets are rare and not performance-critical, this
patch simply skips the checksum verification for them.
Reported-by: NAlexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Acked-by: NAlexander Duyck <alexander.h.duyck@intel.com>

Thanks,
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Rename tcp_tso_segment() to tcp_gso_segment(), to better reflect
what is going on, and ease grep games.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Move the offload callbacks into its own structure.
Signed-off-by: NVlad Yasevich <vyasevic@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Sing GSO support is now separate, pull it out of the module
and make it its own init call.
Remove the cleanup functions as they are no longer called.
Signed-off-by: NVlad Yasevich <vyasevic@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Pull TCPv6 offload functionality into its won file in preparation
for moving it out of the module.
Signed-off-by: NVlad Yasevich <vyasevic@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>