in commit a036244c a fix
was put into place to avoid a kernel panic when a non-
supported traffic class configuration was put into place
and then lldp was enabled/disabled on the link partner
switch.  This fix caused it to be necessary to
unload/reload the driver to reenable DCB once a supported
TC config was in place.

The root cause of the original panic was that the function
i40e_pf_get_default_tc was allowing for a default TC other
than TC 0, and only TC 0 is supported as a default.

This patch removes the get_default_tc function and replaces
it with a #define since there is only one TC supported as
a default.

Change-Id: I448371974e946386d0a7718d73668b450b7c72ef
Signed-off-by: Dave Ertman <david.m.ertman@intel.com>
Tested-by: Ronald Bynoe <ronald.j.bynoe@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

Fix NULL pointer dereference in the case where a macvlan interface is
brought up while the PF is still down:

BUG: unable to handle kernel NULL pointer dereference at 0000000000000010
IP: [<ffffffffa0170fb2>] ixgbe_alloc_rx_buffers+0x42/0x1a0 [ixgbe]

Call Trace:
[<ffffffffa017336b>] ixgbe_configure_rx_ring+0x2eb/0x3d0 [ixgbe]
[<ffffffffa0173811>] ixgbe_fwd_ring_up+0xd1/0x380 [ixgbe]
[<ffffffffa0179709>] ixgbe_fwd_add+0x149/0x230 [ixgbe]
[<ffffffffa0113480>] macvlan_open+0x260/0x2b0 [macvlan]
Reported-by: Matthew Garrett <mjg59@coreos.com>
Signed-off-by: Emil Tantilov <emil.s.tantilov@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

Similar to IPv4, do not consider link state when validating next hops.

Currently, if the link is down default routes can fail to insert:
 $ ip -6 ro add vrf blue default via 2100:2::64 dev eth2
 RTNETLINK answers: No route to host

With this patch the command succeeds.

Fixes: 8c14586f ("net: ipv6: Use passed in table for nexthop lookups")
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

rt6_add_route_info and rt6_add_dflt_router were updated to pull the FIB
table from the device index, but the corresponding rt6_get_route_info
and rt6_get_dflt_router functions were not leading to the failure to
process RA's:

    ICMPv6: RA: ndisc_router_discovery failed to add default route

Fix the 'get' functions by using the table id associated with the
device when applicable.

Also, now that default routes can be added to tables other than the
default table, rt6_purge_dflt_routers needs to be updated as well to
look at all tables. To handle that efficiently, add a flag to the table
denoting if it is has a default route via RA.

Fixes: ca254490 ("net: Add VRF support to IPv6 stack")
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The kalmia_send_init_packet() returns zero or a negative return
code, but gcc has no way of knowing that there cannot be a
positive return code, so it determines that copying the ethernet
address at the end of kalmia_bind() will access uninitialized
data:

drivers/net/usb/kalmia.c: In function ‘kalmia_bind’:
arch/x86/include/asm/string_32.h:78:22: error: ‘*((void *)&ethernet_addr+4)’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
   *((short *)to + 2) = *((short *)from + 2);
                      ^
drivers/net/usb/kalmia.c:138:5: note: ‘*((void *)&ethernet_addr+4)’ was declared here

This warning is harmless, but for consistency, we should make
the check for the return code match what the driver does everywhere
else and just progate it, which then gets rid of the warning.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

Even if sending SCIs is explicitly disabled, the code that creates the
Security Tag might still decide to add it (e.g. if multiple RX SCs are
defined on the MACsec interface).
But because the header length so far only depended on the configuration
option the SCI overwrote the original frame's contents (EtherType and
e.g. the beginning of the IP header) and if encrypted did not visibly
end up in the packet, while the SC flag in the TCI field of the Security
Tag was still set, resulting in invalid MACsec frames.

Fixes: c09440f7 ("macsec: introduce IEEE 802.1AE driver")
Signed-off-by: Tobias Brunner <tobias@strongswan.org>
Acked-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

In SGMII mode, we observed an autonegotiation issue
after power-down-up cycles where the copper side
reports successful link establishment but the
SGMII side's link is down.

This happened in a setup where the at8031 is
connected over SGMII to a eTSEC (fsl gianfar),
but so far could not be reproduced with other
Ethernet device / driver combinations.

This commit adds a wrapper function for at8031
that in case of operating in SGMII mode double
checks SGMII link state when generic aneg_done()
succeeds. It prints a warning on failure but
intentionally does not try to recover from this
state. As a result, if you ever see a warning
'803x_aneg_done: SGMII link is not ok' you will
end up having an Ethernet link up but won't get
any data through. This should not happen, if it
does, please contact the module maintainer.
Signed-off-by: Zefir Kurtisi <zefir.kurtisi@neratec.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This reverts commit 98267311.

Suspending the SGMII alongside the copper side
made the at803x inaccessable while powered down,
e.g. it can't be re-probed after suspend.
Signed-off-by: Zefir Kurtisi <zefir.kurtisi@neratec.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Following Cavium's acquisition of qlogic we need to update all the qlogic
drivers maintainer's entries to point to our new e-mail addresses,
as well as update some of the driver's maintainers as those are no longer
working for Cavium.

I would like to thank Sony Chacko and Rajesh Borundia for their support
and development of our various networking drivers.
Signed-off-by: Yuval Mintz <Yuval.Mintz@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The Hyper-V netvsc driver was looking at the incorrect status bits
in the checksum info. It was setting the receive checksum unnecessary
flag based on the IP header checksum being correct. The checksum
flag is skb is about TCP and UDP checksum status. Because of this
bug, any packet received with bad TCP checksum would be passed
up the stack and to the application causing data corruption.
The problem is reproducible via netcat and netem.

This had a side effect of not doing receive checksum offload
on IPv6. The driver was also also always doing checksum offload
independent of the checksum setting done via ethtool.
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

First bug was added in commit ad6f939a ("ip: Add offset parameter to
ip_cmsg_recv") : Tom missed that ipv4 udp messages could be received on
AF_INET6 socket. ip_cmsg_recv(msg, skb) should have been replaced by
ip_cmsg_recv_offset(msg, skb, sizeof(struct udphdr));

Then commit e6afc8ac ("udp: remove headers from UDP packets before
queueing") forgot to adjust the offsets now UDP headers are pulled
before skb are put in receive queue.

Fixes: ad6f939a ("ip: Add offset parameter to ip_cmsg_recv")
Fixes: e6afc8ac ("udp: remove headers from UDP packets before queueing")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Sam Kumar <samanthakumar@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Tested-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Commit 7303a147 ("sctp: identify chunks that need to be fragmented
at IP level") made the chunk be fragmented at IP level in the next round
if it's size exceed PMTU.

But there still is another case, PMTU can be updated if transport's dst
expires and transport's pmtu_pending is set in sctp_packet_transmit. If
the new PMTU is less than the chunk, the same issue with that commit can
be triggered.

So we should drop this packet and let it retransmit in another round
where it would be fragmented at IP level.

This patch is to fix it by checking the chunk size after PMTU may be
updated and dropping this packet if it's size exceed PMTU.

Fixes: 90017acc ("sctp: Add GSO support")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Neil Horman <nhorman@txudriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The skbuff and sock structure both had missing parameter annotation
values.
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Fix to return error code -EINVAL from the error handling
case instead of 0, as done elsewhere in this function.

Fixes: e420114e ("rocker: introduce worlds infrastructure")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Johan Hedberg says:

====================
pull request: bluetooth 2016-10-21

Here are some more Bluetooth fixes for the 4.9 kernel:

 - Fix to btwilink driver probe function return value
 - Power management fix to hci_bcm
 - Fix to encoding name in scan response data

Please let me know if there are any issues pulling. Thanks.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Most of getsockopt handlers in net/sctp/socket.c check len against
sizeof some structure like:
        if (len < sizeof(int))
                return -EINVAL;

On the first look, the check seems to be correct. But since len is int
and sizeof returns size_t, int gets promoted to unsigned size_t too. So
the test returns false for negative lengths. Yes, (-1 < sizeof(long)) is
false.

Fix this in sctp by explicitly checking len < 0 before any getsockopt
handler is called.

Note that sctp_getsockopt_events already handled the negative case.
Since we added the < 0 check elsewhere, this one can be removed.

If not checked, this is the result:
UBSAN: Undefined behaviour in ../mm/page_alloc.c:2722:19
shift exponent 52 is too large for 32-bit type 'int'
CPU: 1 PID: 24535 Comm: syz-executor Not tainted 4.8.1-0-syzkaller #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.1-0-gb3ef39f-prebuilt.qemu-project.org 04/01/2014
 0000000000000000 ffff88006d99f2a8 ffffffffb2f7bdea 0000000041b58ab3
 ffffffffb4363c14 ffffffffb2f7bcde ffff88006d99f2d0 ffff88006d99f270
 0000000000000000 0000000000000000 0000000000000034 ffffffffb5096422
Call Trace:
 [<ffffffffb3051498>] ? __ubsan_handle_shift_out_of_bounds+0x29c/0x300
...
 [<ffffffffb273f0e4>] ? kmalloc_order+0x24/0x90
 [<ffffffffb27416a4>] ? kmalloc_order_trace+0x24/0x220
 [<ffffffffb2819a30>] ? __kmalloc+0x330/0x540
 [<ffffffffc18c25f4>] ? sctp_getsockopt_local_addrs+0x174/0xca0 [sctp]
 [<ffffffffc18d2bcd>] ? sctp_getsockopt+0x10d/0x1b0 [sctp]
 [<ffffffffb37c1219>] ? sock_common_getsockopt+0xb9/0x150
 [<ffffffffb37be2f5>] ? SyS_getsockopt+0x1a5/0x270
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Vlad Yasevich <vyasevich@gmail.com>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: linux-sctp@vger.kernel.org
Cc: netdev@vger.kernel.org
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Commit 3ac72b7b ("net: fec: align IP header in hardware") breaks
networking on mx28.

There is an erratum on mx28 (ENGR121613 - ENET big endian mode
not compatible with ARM little endian) that requires an additional
byte-swap operation to workaround this problem.

So call swap_buffer() prior to performing the IP header alignment
to restore network functionality on mx28.

Fixes: 3ac72b7b ("net: fec: align IP header in hardware")
Reported-and-tested-by: Henri Roosen <henri.roosen@ginzinger.com>
Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Otherwise we'll overflow the integer. This occurs when layer 3 tunneled
packets are handed off to the IPv6 layer.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Time Sync (PTP) implementation uses the divisor/shift value for converting
the clock ticks to nanoseconds. Driver currently defines shift value as 1,
this results in the nanoseconds value to be calculated as half the actual
value. Hence the user application fails to synchronize the device clock
value with the PTP master device clock. Need to use the 'shift' value of 0.
Signed-off-by: Sony.Chacko <Sony.Chacko@cavium.com>
Signed-off-by: Sudarsana Reddy Kalluru <Sudarsana.Kalluru@cavium.com>
Signed-off-by: Yuval Mintz <Yuval.Mintz@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Sudarsana Reddy Kalluru says:

====================
qed*: fix series.

The patch series contains several minor bug fixes for qed/qede modules.
Please consider applying this to 'net' branch.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Driver uses incorrect APIs to unmap DMA memory which were
mapped using dma_map_single(). This patch fixes it to use
appropriate APIs for un-mapping DMA memory.
Signed-off-by: Manish Chopra <manish.chopra@cavium.com>
Signed-off-by: Yuval Mintz <Yuval.Mintz@cavium.com>
Signed-off-by: Sudarsana Reddy Kalluru <Sudarsana.Kalluru@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

qed_dcbx_query_params() implementation populate the values to input
buffer based on the dcbx mode and, the current negotiated state/params,
the caller of this API need to memset the buffer to zero.
Signed-off-by: Sudarsana Reddy Kalluru <Sudarsana.Kalluru@cavium.com>
Signed-off-by: Yuval Mintz <Yuval.Mintz@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Rx indirection table entries are in the range [0, (rss_count - 1)]. If
user reduces the rss count, the table entries may not be in the ccorrect
range. Need to reconfigure the table with new rss_count as a basis.
Signed-off-by: Sudarsana Reddy Kalluru <Sudarsana.Kalluru@cavium.com>
Signed-off-by: Yuval Mintz <Yuval.Mintz@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

With the current default values for Rx path i.e., 8 queues of 8Kb entries
each with 4Kb size, interface will consume 256Mb for Rx. The default values
causing the driver probe to fail when the system memory is low. Based on
the perforamnce results, rx-ring count value of 1Kb gives the comparable
performance with Rx coalesce timeout of 12 seconds. Updating the default
values.
Signed-off-by: Sudarsana Reddy Kalluru <Sudarsana.Kalluru@cavium.com>
Signed-off-by: Yuval Mintz <Yuval.Mintz@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

During the execution of loopback test, driver may receive the packets which
are not originated by this test, loopback implementation need to skip those
packets.
Signed-off-by: Sudarsana Reddy Kalluru <Sudarsana.Kalluru@cavium.com>
Signed-off-by: Yuval Mintz <Yuval.Mintz@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

RSS configuration is not supported for 100G adapters.
Signed-off-by: Sudarsana Reddy Kalluru <Sudarsana.Kalluru@cavium.com>
Signed-off-by: Yuval Mintz <Yuval.Mintz@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Recent changes in kernel ethtool implementation requires the driver
callback for get_channels() has to populate the values for max tx/rx
coalesce fields.
Signed-off-by: Sudarsana Reddy Kalluru <Sudarsana.Kalluru@cavium.com>
Signed-off-by: Yuval Mintz <Yuval.Mintz@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This reverts commit a681574c
("ipv4: disable BH in set_ping_group_range()") because we never
read ping_group_range in BH context (unlike local_port_range).

Then, since we already have a lock for ping_group_range, those
using ip_local_ports.lock for ping_group_range are clearly typos.

We might consider to share a same lock for both ping_group_range
and local_port_range w.r.t. space saving, but that should be for
net-next.

Fixes: a681574c ("ipv4: disable BH in set_ping_group_range()")
Fixes: ba6b918a ("ping: move ping_group_range out of CONFIG_SYSCTL")
Cc: Eric Dumazet <edumazet@google.com>
Cc: Eric Salo <salo@google.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Florian Fainelli says:

====================
net: dsa: bcm_sf2: Do not rely on kexec_in_progress

These are the two patches following the discussing we had on kexec_in_progress.

Feel free to apply or discard them, thanks!
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

After discussing with Eric, it turns out that, while using
kexec_in_progress is a nice optimization, which prevents us from always
powering on the integrated PHY, let's just turn it on in the shutdown
path.

This removes a dependency on kexec_in_progress which, according to Eric
should not be used by modules

Fixes: 2399d614 ("net: dsa: bcm_sf2: Prevent GPHY shutdown for kexec'd kernels")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This reverts commit 97dcaa0f. Based on
the review discussion with Eric, we will come up with a different fix
for the bcm_sf2 driver which does not make it rely on the
kexec_in_progress value.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This reverts commit bc51dddf ("netns: avoid disabling irq for
netns id") as it was found to cause problems with systems running
SELinux/audit, see the mailing list thread below:

 * http://marc.info/?t=147694653900002&r=1&w=2

Eventually we should be able to reintroduce this code once we have
rewritten the audit multicast code to queue messages much the same
way we do for unicast messages.  A tracking issue for this can be
found below:

 * https://github.com/linux-audit/audit-kernel/issues/23Reported-by: Stephen Smalley <sds@tycho.nsa.gov>
Reported-by: Elad Raz <e@eladraz.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Baozeng reported this deadlock case:

       CPU0                    CPU1
       ----                    ----
  lock([  165.136033] sk_lock-AF_INET6);
                               lock([  165.136033] rtnl_mutex);
                               lock([  165.136033] sk_lock-AF_INET6);
  lock([  165.136033] rtnl_mutex);

Similar to commit 87e9f031
("ipv4: fix a potential deadlock in mcast getsockopt() path")
this is due to we still have a case, ipv6_sock_mc_close(),
where we acquire sk_lock before rtnl_lock. Close this deadlock
with the similar solution, that is always acquire rtnl lock first.

Fixes: baf606d9 ("ipv4,ipv6: grab rtnl before locking the socket")
Reported-by: Baozeng Ding <sploving1@gmail.com>
Tested-by: Baozeng Ding <sploving1@gmail.com>
Cc: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Pablo Neira Ayuso says:

====================
Netfilter fixes for net

The following patchset contains Netfilter fixes for your net tree,
they are:

1) Fix compilation warning in xt_hashlimit on m68k 32-bits, from
   Geert Uytterhoeven.

2) Fix wrong timeout in set elements added from packet path via
   nft_dynset, from Anders K. Pedersen.

3) Remove obsolete nf_conntrack_events_retry_timeout sysctl
   documentation, from Nicolas Dichtel.

4) Ensure proper initialization of log flags via xt_LOG, from
   Liping Zhang.

5) Missing alias to autoload ipcomp, also from Liping Zhang.

6) Missing NFTA_HASH_OFFSET attribute validation, again from Liping.

7) Wrong integer type in the new nft_parse_u32_check() function,
   from Dan Carpenter.

8) Another wrong integer type declaration in nft_exthdr_init, also
   from Dan Carpenter.

9) Fix insufficient mode validation in nft_range.

10) Fix compilation warning in nft_range due to possible uninitialized
    value, from Arnd Bergmann.

11) Zero nf_hook_ops allocated via xt_hook_alloc() in x_tables to
    calm down kmemcheck, from Florian Westphal.

12) Schedule gc_worker() to run again if GC_MAX_EVICTS quota is reached,
    from Nicolas Dichtel.

13) Fix nf_queue() after conversion to single-linked hook list, related
    to incorrect bypass flag handling and incorrect hook point of
    reinjection.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

The bcm_sf2 driver uses kexec_in_progress to know whether it can power
down an integrated PHY during shutdown, and can be built as a module.
Other modules may be using this in the future, so export it.

Fixes: 2399d614 ("net: dsa: bcm_sf2: Prevent GPHY shutdown for kexec'd kernels")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

In commit 4ee3bd4a ("ipv4: disable BH when changing ip local port
range") Cong added BH protection in set_local_port_range() but missed
that same fix was needed in set_ping_group_range()

Fixes: b8f1a556 ("udp: Add function to make source port for UDP tunnels")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Eric Salo <salo@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Baozeng Ding reported KASAN traces showing uses after free in
udp_lib_get_port() and other related UDP functions.

A CONFIG_DEBUG_PAGEALLOC=y kernel would eventually crash.

I could write a reproducer with two threads doing :

static int sock_fd;
static void *thr1(void *arg)
{
	for (;;) {
		connect(sock_fd, (const struct sockaddr *)arg,
			sizeof(struct sockaddr_in));
	}
}

static void *thr2(void *arg)
{
	struct sockaddr_in unspec;

	for (;;) {
		memset(&unspec, 0, sizeof(unspec));
	        connect(sock_fd, (const struct sockaddr *)&unspec,
			sizeof(unspec));
        }
}

Problem is that udp_disconnect() could run without holding socket lock,
and this was causing list corruptions.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Baozeng Ding <sploving1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

For a kernel that is being kexec'd we re-enable the integrated GPHY in
order for the subsequent MDIO bus scan to succeed and properly bind to
the bcm7xxx PHY driver. If we did not do that, the GPHY would be shut
down by the time the MDIO driver is probing the bus, and it would fail
to read the correct PHY OUI and therefore bind to an appropriate PHY
driver. Later on, this would cause DSA not to be able to successfully
attach to the PHY, and the interface would not be created at all.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

After commit 636c2628 ("net: skbuff: Remove errornous length
validation in skb_vlan_pop()") mentioned test case stopped working,
throwing a -12 (ENOMEM) return code. The issue however is not due to
636c2628, but rather due to a buggy test case that got uncovered
from the change in behaviour in 636c2628.

The data_size of that test case for the skb was set to 1. In the
bpf_fill_ld_abs_vlan_push_pop() handler bpf insns are generated that
loop with: reading skb data, pushing 68 tags, reading skb data,
popping 68 tags, reading skb data, etc, in order to force a skb
expansion and thus trigger that JITs recache skb->data. Problem is
that initial data_size is too small.

While before 636c2628, the test silently bailed out due to the
skb->len < VLAN_ETH_HLEN check with returning 0, and now throwing an
error from failing skb_ensure_writable(). Set at least minimum of
ETH_HLEN as an initial length so that on first push of data, equivalent
pop will succeed.

Fixes: 4d9c5c53 ("test_bpf: add bpf_skb_vlan_push/pop() tests")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Currently, GRO can do unlimited recursion through the gro_receive
handlers.  This was fixed for tunneling protocols by limiting tunnel GRO
to one level with encap_mark, but both VLAN and TEB still have this
problem.  Thus, the kernel is vulnerable to a stack overflow, if we
receive a packet composed entirely of VLAN headers.

This patch adds a recursion counter to the GRO layer to prevent stack
overflow.  When a gro_receive function hits the recursion limit, GRO is
aborted for this skb and it is processed normally.  This recursion
counter is put in the GRO CB, but could be turned into a percpu counter
if we run out of space in the CB.

Thanks to Vladimír Beneš <vbenes@redhat.com> for the initial bug report.

Fixes: CVE-2016-7039
Fixes: 9b174d88 ("net: Add Transparent Ethernet Bridging GRO support.")
Fixes: 66e5133f ("vlan: Add GRO support for non hardware accelerated vlan")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Reviewed-by: Jiri Benc <jbenc@redhat.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Acked-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>