Sending zero checksum is ok for TCP, but not for UDP.

UDPv6 receiver should by default drop a frame with a 0 checksum,
and UDPv4 would not verify the checksum and might accept a corrupted
packet.

Simply replace such checksum by 0xffff, regardless of transport.

This error was caught on SIT tunnels, but seems generic.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: Maciej Żenczykowski <maze@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Acked-by: NMaciej Żenczykowski <maze@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

At accept() time, it is possible the parent has a non zero
sk_err_soft, leftover from a prior error.

Make sure we do not leave this value in the child, as it
makes future getsockopt(SO_ERROR) calls quite unreliable.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Acked-by: NSoheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When transmitting on a packet socket with PACKET_VNET_HDR and
PACKET_QDISC_BYPASS, validate device support for features requested
in vnet_hdr.

Drop TSO packets sent to devices that do not support TSO or have the
feature disabled. Note that the latter currently do process those
packets correctly, regardless of not advertising the feature.

Because of SKB_GSO_DODGY, it is not sufficient to test device features
with netif_needs_gso. Full validate_xmit_skb is needed.

Switch to software checksum for non-TSO packets that request checksum
offload if that device feature is unsupported or disabled. Note that
similar to the TSO case, device drivers may perform checksum offload
correctly even when not advertising it.

When switching to software checksum, packets hit skb_checksum_help,
which has two BUG_ON checksum not in linear segment. Packet sockets
always allocate at least up to csum_start + csum_off + 2 as linear.

Tested by running github.com/wdebruij/kerneltools/psock_txring_vnet.c

  ethtool -K eth0 tso off tx on
  psock_txring_vnet -d $dst -s $src -i eth0 -l 2000 -n 1 -q -v
  psock_txring_vnet -d $dst -s $src -i eth0 -l 2000 -n 1 -q -v -N

  ethtool -K eth0 tx off
  psock_txring_vnet -d $dst -s $src -i eth0 -l 1000 -n 1 -q -v -G
  psock_txring_vnet -d $dst -s $src -i eth0 -l 1000 -n 1 -q -v -G -N

v2:
  - add EXPORT_SYMBOL_GPL(validate_xmit_skb_list)

Fixes: d346a3fa ("packet: introduce PACKET_QDISC_BYPASS socket option")
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Acked-by: NEric Dumazet <edumazet@google.com>
Acked-by: NDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

gcc warns about an uninitialized pointer dereference in the vlan
priority handling:

net/core/flow_dissector.c: In function '__skb_flow_dissect':
net/core/flow_dissector.c:281:61: error: 'vlan' may be used uninitialized in this function [-Werror=maybe-uninitialized]

As pointed out by Jiri Pirko, the variable is never actually used
without being initialized first as the only way it end up uninitialized
is with skb_vlan_tag_present(skb)==true, and that means it does not
get accessed.

However, the warning hints at some related issues that I'm addressing
here:

- the second check for the vlan tag is different from the first one
  that tests the skb for being NULL first, causing both the warning
  and a possible NULL pointer dereference that was not entirely fixed.
- The same patch that introduced the NULL pointer check dropped an
  earlier optimization that skipped the repeated check of the
  protocol type
- The local '_vlan' variable is referenced through the 'vlan' pointer
  but the variable has gone out of scope by the time that it is
  accessed, causing undefined behavior

Caching the result of the 'skb && skb_vlan_tag_present(skb)' check
in a local variable allows the compiler to further optimize the
later check. With those changes, the warning also disappears.

Fixes: 3805a938 ("flow_dissector: Check skb for VLAN only if skb specified.")
Fixes: d5709f7a ("flow_dissector: For stripped vlan, get vlan info from skb->vlan_tci")
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NJiri Pirko <jiri@mellanox.com>
Acked-by: NEric Garver <e@erig.me>
Signed-off-by: NDavid 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: NStephen Smalley <sds@tycho.nsa.gov>
Reported-by: NElad Raz <e@eladraz.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NPaul Moore <paul@paul-moore.com>
Signed-off-by: NDavid 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: NSabrina Dubroca <sd@queasysnail.net>
Reviewed-by: NJiri Benc <jbenc@redhat.com>
Acked-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Acked-by: NTom Herbert <tom@herbertland.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Tamir reported the following trace when processing ARP requests received
via a vlan device on top of a VLAN-aware bridge:

 NMI watchdog: BUG: soft lockup - CPU#1 stuck for 22s! [swapper/1:0]
[...]
 CPU: 1 PID: 0 Comm: swapper/1 Tainted: G        W       4.8.0-rc7 #1
 Hardware name: Mellanox Technologies Ltd. "MSN2100-CB2F"/"SA001017", BIOS 5.6.5 06/07/2016
 task: ffff88017edfea40 task.stack: ffff88017ee10000
 RIP: 0010:[<ffffffff815dcc73>]  [<ffffffff815dcc73>] netdev_all_lower_get_next_rcu+0x33/0x60
[...]
 Call Trace:
  <IRQ>
  [<ffffffffa015de0a>] mlxsw_sp_port_lower_dev_hold+0x5a/0xa0 [mlxsw_spectrum]
  [<ffffffffa016f1b0>] mlxsw_sp_router_netevent_event+0x80/0x150 [mlxsw_spectrum]
  [<ffffffff810ad07a>] notifier_call_chain+0x4a/0x70
  [<ffffffff810ad13a>] atomic_notifier_call_chain+0x1a/0x20
  [<ffffffff815ee77b>] call_netevent_notifiers+0x1b/0x20
  [<ffffffff815f2eb6>] neigh_update+0x306/0x740
  [<ffffffff815f38ce>] neigh_event_ns+0x4e/0xb0
  [<ffffffff8165ea3f>] arp_process+0x66f/0x700
  [<ffffffff8170214c>] ? common_interrupt+0x8c/0x8c
  [<ffffffff8165ec29>] arp_rcv+0x139/0x1d0
  [<ffffffff816e505a>] ? vlan_do_receive+0xda/0x320
  [<ffffffff815e3794>] __netif_receive_skb_core+0x524/0xab0
  [<ffffffff815e6830>] ? dev_queue_xmit+0x10/0x20
  [<ffffffffa06d612d>] ? br_forward_finish+0x3d/0xc0 [bridge]
  [<ffffffffa06e5796>] ? br_handle_vlan+0xf6/0x1b0 [bridge]
  [<ffffffff815e3d38>] __netif_receive_skb+0x18/0x60
  [<ffffffff815e3dc0>] netif_receive_skb_internal+0x40/0xb0
  [<ffffffff815e3e4c>] netif_receive_skb+0x1c/0x70
  [<ffffffffa06d7856>] br_pass_frame_up+0xc6/0x160 [bridge]
  [<ffffffffa06d63d7>] ? deliver_clone+0x37/0x50 [bridge]
  [<ffffffffa06d656c>] ? br_flood+0xcc/0x160 [bridge]
  [<ffffffffa06d7b14>] br_handle_frame_finish+0x224/0x4f0 [bridge]
  [<ffffffffa06d7f94>] br_handle_frame+0x174/0x300 [bridge]
  [<ffffffff815e3599>] __netif_receive_skb_core+0x329/0xab0
  [<ffffffff81374815>] ? find_next_bit+0x15/0x20
  [<ffffffff8135e802>] ? cpumask_next_and+0x32/0x50
  [<ffffffff810c9968>] ? load_balance+0x178/0x9b0
  [<ffffffff815e3d38>] __netif_receive_skb+0x18/0x60
  [<ffffffff815e3dc0>] netif_receive_skb_internal+0x40/0xb0
  [<ffffffff815e3e4c>] netif_receive_skb+0x1c/0x70
  [<ffffffffa01544a1>] mlxsw_sp_rx_listener_func+0x61/0xb0 [mlxsw_spectrum]
  [<ffffffffa005c9f7>] mlxsw_core_skb_receive+0x187/0x200 [mlxsw_core]
  [<ffffffffa007332a>] mlxsw_pci_cq_tasklet+0x63a/0x9b0 [mlxsw_pci]
  [<ffffffff81091986>] tasklet_action+0xf6/0x110
  [<ffffffff81704556>] __do_softirq+0xf6/0x280
  [<ffffffff8109213f>] irq_exit+0xdf/0xf0
  [<ffffffff817042b4>] do_IRQ+0x54/0xd0
  [<ffffffff8170214c>] common_interrupt+0x8c/0x8c

The problem is that netdev_all_lower_get_next_rcu() never advances the
iterator, thereby causing the loop over the lower adjacency list to run
forever.

Fix this by advancing the iterator and avoid the infinite loop.

Fixes: 7ce856aa ("mlxsw: spectrum: Add couple of lower device helper functions")
Signed-off-by: NIdo Schimmel <idosch@mellanox.com>
Reported-by: NTamir Winetroub <tamirw@mellanox.com>
Reviewed-by: NJiri Pirko <jiri@mellanox.com>
Acked-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fixes a panic when calling eth_get_headlen(). Noticed on i40e driver.

Fixes: d5709f7a ("flow_dissector: For stripped vlan, get vlan info from skb->vlan_tci")
Signed-off-by: NEric Garver <e@erig.me>
Reviewed-by: NJakub Sitnicki <jkbs@redhat.com>
Acked-by: NAmir Vadai <amir@vadai.me>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

reuseport_add_sock() is not used from a module,
no need to export it.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

After Jesper commit back in linux-3.18, we trigger a lockdep
splat in proc_create_data() while allocating memory from
pktgen_change_name().

This patch converts t->if_lock to a mutex, since it is now only
used from control path, and adds proper locking to pktgen_change_name()

1) pktgen_thread_lock to protect the outer loop (iterating threads)
2) t->if_lock to protect the inner loop (iterating devices)

Note that before Jesper patch, pktgen_change_name() was lacking proper
protection, but lockdep was not able to detect the problem.

Fixes: 8788370a ("pktgen: RCU-ify "if_list" to remove lock in next_to_run()")
Reported-by: NJohn Sperbeck <jsperbeck@google.com>
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The "vf_vlan_info" struct ends with a 2 byte struct hole so we have to
memset it to ensure that no stack information is revealed to user space.

Fixes: 79aab093 ('net: Update API for VF vlan protocol 802.1ad support')
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The __latent_entropy gcc attribute can be used only on functions and
variables.  If it is on a function then the plugin will instrument it for
gathering control-flow entropy. If the attribute is on a variable then
the plugin will initialize it with random contents.  The variable must
be an integer, an integer array type or a structure with integer fields.

These specific functions have been selected because they are init
functions (to help gather boot-time entropy), are called at unpredictable
times, or they have variable loops, each of which provide some level of
latent entropy.
Signed-off-by: NEmese Revfy <re.emese@gmail.com>
[kees: expanded commit message]
Signed-off-by: NKees Cook <keescook@chromium.org>

The cgroup core and the memory controller need to track socket ownership
for different purposes, but the tracking sites being entirely different
is kind of ugly.

Be a better citizen and rename the memory controller callbacks to match
the cgroup core callbacks, then move them to the same place.

[akpm@linux-foundation.org: coding-style fixes]
Link: http://lkml.kernel.org/r/20160914194846.11153-3-hannes@cmpxchg.orgSigned-off-by: NJohannes Weiner <hannes@cmpxchg.org>
Acked-by: NTejun Heo <tj@kernel.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This is a respin of a patch to fix a relatively easily reproducible kernel
panic related to the all_adj_list handling for netdevs in recent kernels.

The following sequence of commands will reproduce the issue:

ip link add link eth0 name eth0.100 type vlan id 100
ip link add link eth0 name eth0.200 type vlan id 200
ip link add name testbr type bridge
ip link set eth0.100 master testbr
ip link set eth0.200 master testbr
ip link add link testbr mac0 type macvlan
ip link delete dev testbr

This creates an upper/lower tree of (excuse the poor ASCII art):

            /---eth0.100-eth0
mac0-testbr-
            \---eth0.200-eth0

When testbr is deleted, the all_adj_lists are walked, and eth0 is deleted twice from
the mac0 list. Unfortunately, during setup in __netdev_upper_dev_link, only one
reference to eth0 is added, so this results in a panic.

This change adds reference count propagation so things are handled properly.

Matthias Schiffer reported a similar crash in batman-adv:

https://github.com/freifunk-gluon/gluon/issues/680
https://www.open-mesh.org/issues/247

which this patch also seems to resolve.
Signed-off-by: NAndrew Collins <acollins@cradlepoint.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

skb_vlan_pop/push were too generic, trying to support the cases where
skb->data is at mac header, and cases where skb->data is arbitrarily
elsewhere.

Supporting an arbitrary skb->data was complex and bogus:
 - It failed to unwind skb->data to its original location post actual
   pop/push.
   (Also, semantic is not well defined for unwinding: If data was into
    the eth header, need to use same offset from start; But if data was
    at network header or beyond, need to adjust the original offset
    according to the push/pull)
 - It mangled the rcsum post actual push/pop, without taking into account
   that the eth bytes might already have been pulled out of the csum.

Most callers (ovs, bpf) already had their skb->data at mac_header upon
invoking skb_vlan_pop/push.
Last caller that failed to do so (act_vlan) has been recently fixed.

Therefore, to simplify things, no longer support arbitrary skb->data
inputs for skb_vlan_pop/push().

skb->data is expected to be exactly at mac_header; WARN otherwise.
Signed-off-by: NShmulik Ladkani <shmulik.ladkani@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Pravin Shelar <pshelar@ovn.org>
Cc: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

since pipe_lock is the outermost now, we don't need to drop/regain
socket locks around the call of splice_to_pipe() from skb_splice_bits(),
which kills the need to have a socket-specific callback; we can just
call splice_to_pipe() and be done with that.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

With the newly added support for IFLA_VF_VLAN_LIST netlink messages,
we get a warning about potential uninitialized variable use in
the parsing of the user input when enabling the -Wmaybe-uninitialized
warning:

net/core/rtnetlink.c: In function 'do_setvfinfo':
net/core/rtnetlink.c:1756:9: error: 'ivvl$' may be used uninitialized in this function [-Werror=maybe-uninitialized]

I have not been able to prove whether it is possible to arrive in
this code with an empty IFLA_VF_VLAN_LIST block, but if we do,
then ndo_set_vf_vlan gets called with uninitialized arguments.

This adds an explicit check for an empty list, making it obvious
to the reader and the compiler that this cannot happen.

Fixes: 79aab093 ("net: Update API for VF vlan protocol 802.1ad support")
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Reviewed-by: NMoshe Shemesh <moshe@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The commit 879c7220 ("net: pktgen: Observe needed_headroom
of the device") increased the 'pkt_overhead' field value by
LL_RESERVED_SPACE.
As a side effect the generated packet size, computed as:

	/* Eth + IPh + UDPh + mpls */
	datalen = pkt_dev->cur_pkt_size - 14 - 20 - 8 -
		  pkt_dev->pkt_overhead;

is decreased by the same value.
The above changed slightly the behavior of existing pktgen users,
and made the procfs interface somewhat inconsistent.
Fix it by restoring the previous pkt_overhead value and using
LL_RESERVED_SPACE as extralen in skb allocation.
Also, change pktgen_alloc_skb() to only partially reserve
the headroom to allow the caller to prefetch from ll header
start.

v1 -> v2:
 - fixed some typos in the comments

Fixes: 879c7220 ("net: pktgen: Observe needed_headroom of the device")
Suggested-by: NBen Greear <greearb@candelatech.com>
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Since commit 900f65d3 ("tcp: move duplicate code from
tcp_v4_init_sock()/tcp_v6_init_sock()") we no longer need
to export sk_stream_write_space()

From: Eric Dumazet <edumazet@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This commit ensures that the rcu read-side lock is held while the
ingress hook is called.  This ensures that a call to nf_hook_slow (and
ultimately nf_ingress) will be read protected.
Signed-off-by: NAaron Conole <aconole@bytheb.org>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

Introduce new rtnl UAPI that exposes a list of vlans per VF, giving
the ability for user-space application to specify it for the VF, as an
option to support 802.1ad.
We adjusted IP Link tool to support this option.

For future use cases, the new UAPI supports multiple vlans. For now we
limit the list size to a single vlan in kernel.
Add IFLA_VF_VLAN_LIST in addition to IFLA_VF_VLAN to keep backward
compatibility with older versions of IP Link tool.

Add a vlan protocol parameter to the ndo_set_vf_vlan callback.
We kept 802.1Q as the drivers' default vlan protocol.
Suitable ip link tool command examples:
  Set vf vlan protocol 802.1ad:
    ip link set eth0 vf 1 vlan 100 proto 802.1ad
  Set vf to VST (802.1Q) mode:
    ip link set eth0 vf 1 vlan 100 proto 802.1Q
  Or by omitting the new parameter
    ip link set eth0 vf 1 vlan 100
Signed-off-by: NMoshe Shemesh <moshe@mellanox.com>
Signed-off-by: NTariq Toukan <tariqt@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

With the newly enforced limit on the number of namespaces,
we get a build warning if CONFIG_NETNS is disabled:

net/core/net_namespace.c:273:13: error: 'dec_net_namespaces' defined but not used [-Werror=unused-function]
net/core/net_namespace.c:268:24: error: 'inc_net_namespaces' defined but not used [-Werror=unused-function]

This moves the two added functions inside the #ifdef that guards
their callers.

Fixes: 70328660 ("netns: Add a limit on the number of net namespaces")
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>

Add a small helper that complements 36bbef52 ("bpf: direct packet
write and access for helpers for clsact progs") for invalidating the
current skb->hash after mangling on headers via direct packet write.
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Same motivation as in commit 80b48c44 ("bpf: don't use raw processor
id in generic helper"), but this time for XDP typed programs. Thus, allow
for preemption checks when we have DEBUG_PREEMPT enabled, and otherwise
use the raw variant.
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We need to use skb_to_full_sk() helper introduced in commit bd5eb35f
("xfrm: take care of request sockets") as otherwise we miss tcp synack
messages, since ownership is on request socket and therefore it would
miss the sk_fullsock() check. Use skb_to_full_sk() as also done similarly
in the bpf_get_cgroup_classid() helper via 2309236c ("cls_cgroup:
get sk_classid only from full sockets") fix to not let this fall through.

Fixes: 4a482f34 ("cgroup: bpf: Add bpf_skb_in_cgroup_proto")
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Return -EPERM if an owning user namespace is outside of a process
current user namespace.

v2: In a first version ns_get_owner returned ENOENT for init_user_ns.
    This special cases was removed from this version. There is nothing
    outside of init_user_ns, so we can return EPERM.
v3: rename ns->get_owner() to ns->owner(). get_* usually means that it
grabs a reference.
Acked-by: NSerge Hallyn <serge@hallyn.com>
Signed-off-by: NAndrei Vagin <avagin@openvz.org>
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>

The current error codes returned when a the per user per user
namespace limit are hit (EINVAL, EUSERS, and ENFILE) are wrong.  I
asked for advice on linux-api and it we made clear that those were
the wrong error code, but a correct effor code was not suggested.

The best general error code I have found for hitting a resource limit
is ENOSPC.  It is not perfect but as it is unambiguous it will serve
until someone comes up with a better error code.
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>

Fix 'skb_vlan_pop' to use eth_type_vlan instead of directly comparing
skb->protocol to ETH_P_8021Q or ETH_P_8021AD.
Signed-off-by: NShmulik Ladkani <shmulik.ladkani@gmail.com>
Reviewed-by: NPravin B Shelar <pshelar@ovn.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In 93515d53
  "net: move vlan pop/push functions into common code"
skb_vlan_pop was moved from its private location in openvswitch to
skbuff common code.

In case skb has non hw-accel vlan tag, the original 'pop_vlan()' assured
that skb->len is sufficient (if skb->len < VLAN_ETH_HLEN then pop was
considered a no-op).

This validation was moved as is into the new common 'skb_vlan_pop'.

Alas, in its original location (openvswitch), there was a guarantee that
'data' points to the mac_header, therefore the 'skb->len < VLAN_ETH_HLEN'
condition made sense.
However there's no such guarantee in the generic 'skb_vlan_pop'.

For short packets received in rx path going through 'skb_vlan_pop',
this causes 'skb_vlan_pop' to fail pop-ing a valid vlan hdr (in the non
hw-accel case) or to fail moving next tag into hw-accel tag.

Remove the 'skb->len < VLAN_ETH_HLEN' condition entirely:
It is superfluous since inner '__skb_vlan_pop' already verifies there
are VLAN_ETH_HLEN writable bytes at the mac_header.

Note this presents a slight change to skb_vlan_pop() users:
In case total length is smaller than VLAN_ETH_HLEN, skb_vlan_pop() now
returns an error, as opposed to previous "no-op" behavior.
Existing callers (e.g. tc act vlan, ovs) usually drop the packet if
'skb_vlan_pop' fails.

Fixes: 93515d53 ("net: move vlan pop/push functions into common code")
Signed-off-by: NShmulik Ladkani <shmulik.ladkani@gmail.com>
Cc: Pravin Shelar <pshelar@ovn.org>
Reviewed-by: NPravin B Shelar <pshelar@ovn.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This exports the functionality of extracting the tag from the payload,
without moving next vlan tag into hw accel tag.
Signed-off-by: NShmulik Ladkani <shmulik.ladkani@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This work implements direct packet access for helpers and direct packet
write in a similar fashion as already available for XDP types via commits
4acf6c0b ("bpf: enable direct packet data write for xdp progs") and
6841de8b ("bpf: allow helpers access the packet directly"), and as a
complementary feature to the already available direct packet read for tc
(cls/act) programs.

For enabling this, we need to introduce two helpers, bpf_skb_pull_data()
and bpf_csum_update(). The first is generally needed for both, read and
write, because they would otherwise only be limited to the current linear
skb head. Usually, when the data_end test fails, programs just bail out,
or, in the direct read case, use bpf_skb_load_bytes() as an alternative
to overcome this limitation. If such data sits in non-linear parts, we
can just pull them in once with the new helper, retest and eventually
access them.

At the same time, this also makes sure the skb is uncloned, which is, of
course, a necessary condition for direct write. As this needs to be an
invariant for the write part only, the verifier detects writes and adds
a prologue that is calling bpf_skb_pull_data() to effectively unclone the
skb from the very beginning in case it is indeed cloned. The heuristic
makes use of a similar trick that was done in 233577a2 ("net: filter:
constify detection of pkt_type_offset"). This comes at zero cost for other
programs that do not use the direct write feature. Should a program use
this feature only sparsely and has read access for the most parts with,
for example, drop return codes, then such write action can be delegated
to a tail called program for mitigating this cost of potential uncloning
to a late point in time where it would have been paid similarly with the
bpf_skb_store_bytes() as well. Advantage of direct write is that the
writes are inlined whereas the helper cannot make any length assumptions
and thus needs to generate a call to memcpy() also for small sizes, as well
as cost of helper call itself with sanity checks are avoided. Plus, when
direct read is already used, we don't need to cache or perform rechecks
on the data boundaries (due to verifier invalidating previous checks for
helpers that change skb->data), so more complex programs using rewrites
can benefit from switching to direct read plus write.

For direct packet access to helpers, we save the otherwise needed copy into
a temp struct sitting on stack memory when use-case allows. Both facilities
are enabled via may_access_direct_pkt_data() in verifier. For now, we limit
this to map helpers and csum_diff, and can successively enable other helpers
where we find it makes sense. Helpers that definitely cannot be allowed for
this are those part of bpf_helper_changes_skb_data() since they can change
underlying data, and those that write into memory as this could happen for
packet typed args when still cloned. bpf_csum_update() helper accommodates
for the fact that we need to fixup checksum_complete when using direct write
instead of bpf_skb_store_bytes(), meaning the programs can use available
helpers like bpf_csum_diff(), and implement csum_add(), csum_sub(),
csum_block_add(), csum_block_sub() equivalents in eBPF together with the
new helper. A usage example will be provided for iproute2's examples/bpf/
directory.
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Since commit 8a29111c ("net: gro: allow to build full sized skb")
gro may build buffers with a frag_list. This can hurt forwarding
because most NICs can't offload such packets, they need to be
segmented in software. This patch splits buffers with a frag_list
at the frag_list pointer into buffers that can be TSO offloaded.
Signed-off-by: NSteffen Klassert <steffen.klassert@secunet.com>
Acked-by: NAlexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When a socket is cloned, the associated sock_cgroup_data is duplicated
but not its reference on the cgroup.  As a result, the cgroup reference
count will underflow when both sockets are destroyed later on.

Fixes: bd1060a1 ("sock, cgroup: add sock->sk_cgroup")
Link: http://lkml.kernel.org/r/20160914194846.11153-2-hannes@cmpxchg.orgSigned-off-by: NJohannes Weiner <hannes@cmpxchg.org>
Acked-by: NTejun Heo <tj@kernel.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
Cc: <stable@vger.kernel.org>	[4.5+]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add a nested attribute of offload stats to if_stats_msg
named IFLA_STATS_LINK_OFFLOAD_XSTATS.
Under it, add SW stats, meaning stats only per packets that went via
slowpath to the cpu, named IFLA_OFFLOAD_XSTATS_CPU_HIT.
Signed-off-by: NNogah Frankel <nogahf@mellanox.com>
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Acked-by: NNikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The IS_ENABLED() macro checks if a Kconfig symbol has been enabled either
built-in or as a module, use that macro instead of open coding the same.

Using the macro makes the code more readable by helping abstract away some
of the Kconfig built-in and module enable details.
Signed-off-by: NJavier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This work adds BPF_CALL_<n>() macros and converts all the eBPF helper functions
to use them, in a similar fashion like we do with SYSCALL_DEFINE<n>() macros
that are used today. Motivation for this is to hide all the register handling
and all necessary casts from the user, so that it is done automatically in the
background when adding a BPF_CALL_<n>() call.

This makes current helpers easier to review, eases to write future helpers,
avoids getting the casting mess wrong, and allows for extending all helpers at
once (f.e. build time checks, etc). It also helps detecting more easily in
code reviews that unused registers are not instrumented in the code by accident,
breaking compatibility with existing programs.

BPF_CALL_<n>() internals are quite similar to SYSCALL_DEFINE<n>() ones with some
fundamental differences, for example, for generating the actual helper function
that carries all u64 regs, we need to fill unused regs, so that we always end up
with 5 u64 regs as an argument.

I reviewed several 0-5 generated BPF_CALL_<n>() variants of the .i results and
they look all as expected. No sparse issue spotted. We let this also sit for a
few days with Fengguang's kbuild test robot, and there were no issues seen. On
s390, it barked on the "uses dynamic stack allocation" notice, which is an old
one from bpf_perf_event_output{,_tp}() reappearing here due to the conversion
to the call wrapper, just telling that the perf raw record/frag sits on stack
(gcc with s390's -mwarn-dynamicstack), but that's all. Did various runtime tests
and they were fine as well. All eBPF helpers are now converted to use these
macros, getting rid of a good chunk of all the raw castings.
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When fetching ifindex, we don't need to test dev for being NULL since
we're always guaranteed to have a valid dev for clsact programs. Thus,
avoid this test in fast path.
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add BPF_SIZEOF() and BPF_FIELD_SIZEOF() macros to improve the code a bit
which otherwise often result in overly long bytes_to_bpf_size(sizeof())
and bytes_to_bpf_size(FIELD_SIZEOF()) lines. So place them into a macro
helper instead. Moreover, we currently have a BUILD_BUG_ON(BPF_FIELD_SIZEOF())
check in convert_bpf_extensions(), but we should rather make that generic
as well and add a BUILD_BUG_ON() test in all BPF_SIZEOF()/BPF_FIELD_SIZEOF()
users to detect any rewriter size issues at compile time. Note, there are
currently none, but we want to assert that it stays this way.
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Some minor misc cleanups, f.e. use sizeof(__u32) instead of hardcoding
and in __bpf_skb_max_len(), I missed that we always have skb->dev valid
anyway, so we can drop the unneeded test for dev; also few more other
misc bits addressed here.
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This structure is defined but never used. Flagged with W=1
Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>
Acked-by: NRoopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>