syzkaller was able to generate the following XDP program ...

  (18) r0 = 0x0
  (61) r5 = *(u32 *)(r1 +12)
  (04) (u32) r0 += (u32) 0
  (95) exit

... and trigger a NULL pointer dereference in ___bpf_prog_run()
via bpf_prog_test_run_xdp() where this was attempted to run.

Reason is that recent xdp_rxq_info addition to XDP programs
updated all drivers, but not bpf_prog_test_run_xdp(), where
xdp_buff is set up. Thus when context rewriter does the deref
on the netdev it's NULL at runtime. Fix it by using xdp_rxq
from loopback dev. __netif_get_rx_queue() helper can also be
reused in various other locations later on.

Fixes: 02dd3291b2f0 ("bpf: finally expose xdp_rxq_info to XDP bpf-programs")
Reported-by: syzbot+1eb094057b338eb1fc00@syzkaller.appspotmail.com
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

This patch promotes the local change_tx_queue_len() to a core
helper function, dev_change_tx_queue_len(), so that rtnetlink
and net-sysfs could share the code. This also prepares for the
following patch.

Note, the -EFAULT in the original code doesn't make sense,
we should propagate the errno from notifiers.

Cc: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Steffen Klassert says:

====================
pull request (net-next): ipsec-next 2018-01-26

One last patch for this development cycle:

1) Add ESN support for IPSec HW offload.
   From Yossef Efraim.

Please pull or let me know if there are problems.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Only two of dev_ioctl() callers may pass SIOCGIFCONF to it.
Separating that codepath from the rest of dev_ioctl() allows both
to simplify dev_ioctl() itself (all other cases work with struct ifreq *)
*and* seriously simplify the compat side of that beast: all it takes
is passing to inet_gifconf() an extra argument - the size of individual
records (sizeof(struct ifreq) or sizeof(struct compat_ifreq)).  With
dev_ifconf() called directly from sock_do_ioctl()/compat_dev_ifconf()
that's easy to arrange.

As the result, compat side of SIOCGIFCONF doesn't need any
allocations, copy_in_user() back and forth, etc.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Fix the documentation warning:

include/linux/netdevice.h:1939: warning: Excess struct member 'carrier_changes' description in 'net_device'

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Fixes: b2d3bcfa26a7 ("net: core: Expose number of link up/down transitions")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Expose the number of times the link has been going UP or DOWN, and
update the "carrier_changes" counter to be the sum of these two events.
While at it, also update the sysfs-class-net documentation to cover:
carrier_changes (3.15), carrier_up_count (4.16) and carrier_down_count
(4.16)

Signed-off-by: David Decotigny <decot@googlers.com>
[Florian:
* rebase
* add documentation
* merge carrier_changes with up/down counters]
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This patch adds ESN support to IPsec device offload.
Adding new xfrm device operation to synchronize device ESN.

Signed-off-by: Yossef Efraim <yossefe@mellanox.com>
Signed-off-by: Shannon Nelson <shannon.nelson@oracle.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

Daniel Borkmann says:

====================
pull-request: bpf-next 2018-01-17

The following pull-request contains BPF updates for your *net-next* tree.

The main changes are:

1) Add initial BPF map offloading for nfp driver. Currently only
   programs were supported so far w/o being able to access maps.
   Offloaded programs are right now only allowed to perform map
   lookups, and control path is responsible for populating the
   maps. BPF core infrastructure along with nfp implementation is
   provided, from Jakub.

2) Various follow-ups to Josef's BPF error injections. More
   specifically that includes: properly check whether the error
   injectable event is on function entry or not, remove the percpu
   bpf_kprobe_override and rather compare instruction pointer
   with original one, separate error-injection from kprobes since
   it's not limited to it, add injectable error types in order to
   specify what is the expected type of failure, and last but not
   least also support the kernel's fault injection framework, all
   from Masami.

3) Various misc improvements and cleanups to the libbpf Makefile.
   That is, fix permissions when installing BPF header files, remove
   unused variables and functions, and also install the libbpf.h
   header, from Jesper.

4) When offloading to nfp JIT and the BPF insn is unsupported in the
   JIT, then reject right at verification time. Also fix libbpf with
   regards to ELF section name matching by properly treating the
   program type as prefix. Both from Quentin.

5) Add -DPACKAGE to bpftool when including bfd.h for the disassembler.
   This is needed, for example, when building libfd from source as
   bpftool doesn't supply a config.h for bfd.h. Fix from Jiong.

6) xdp_convert_ctx_access() is simplified since it doesn't need to
   set target size during verification, from Jesper.

7) Let bpftool properly recognize BPF_PROG_TYPE_CGROUP_DEVICE
   program types, from Roman.

8) Various functions in BPF cpumap were not declared static, from Wei.

9) Fix a double semicolon in BPF samples, from Luis.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

BPF map offload follow similar path to program offload.  At creation
time users may specify ifindex of the device on which they want to
create the map.  Map will be validated by the kernel's
.map_alloc_check callback and device driver will be called for the
actual allocation.  Map will have an empty set of operations
associated with it (save for alloc and free callbacks).  The real
device callbacks are kept in map->offload->dev_ops because they
have slightly different signatures.  Map operations are called in
process context so the driver may communicate with HW freely,
msleep(), wait() etc.

Map alloc and free callbacks are muxed via existing .ndo_bpf, and
are always called with rtnl lock held.  Maps and programs are
guaranteed to be destroyed before .ndo_uninit (i.e. before
unregister_netdev() returns).  Map callbacks are invoked with
bpf_devs_lock *read* locked, drivers must take care of exclusive
locking if necessary.

All offload-specific branches are marked with unlikely() (through
bpf_map_is_dev_bound()), given that branch penalty will be
negligible compared to IO anyway, and we don't want to penalize
SW path unnecessarily.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>