"ip route get $daddr iif eth0 from $saddr" causes:
 BUG: KASAN: use-after-free in ip_route_input_rcu+0x1535/0x1b50
 Call Trace:
  ip_route_input_rcu+0x1535/0x1b50
  ip_route_input_noref+0xf9/0x190
  tcp_v4_early_demux+0x1a4/0x2b0
  ip_rcv+0xbcb/0xc05
  __netif_receive_skb+0x9c/0xd0
  netif_receive_skb_internal+0x5a8/0x890

Problem is that inet_rtm_getroute calls either ip_route_input_rcu (if an
iif was provided) or ip_route_output_key_hash_rcu.

But ip_route_input_rcu, unlike ip_route_output_key_hash_rcu, already
associates the dst_entry with the skb.  This clears the SKB_DST_NOREF
bit (i.e. skb_dst_drop will release/free the entry while it should not).

Thus only set the dst if we called ip_route_output_key_hash_rcu().

I tested this patch by running:
 while true;do ip r get 10.0.1.2;done > /dev/null &
 while true;do ip r get 10.0.1.2 iif eth0  from 10.0.1.1;done > /dev/null &
... and saw no crash or memory leak.

Cc: Roopa Prabhu <roopa@cumulusnetworks.com>
Cc: David Ahern <dsahern@gmail.com>
Fixes: ba52d61e ("ipv4: route: restore skb_dst_set in inet_rtm_getroute")
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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: e89e9cf5 ("[IPv4/IPv6]: UFO Scatter-gather approach")
Reported-by: NAndrey Konovalov <andreyknvl@google.com>
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit dcd87999 ("igmp: net: Move igmp namespace init to correct file")
moved the igmp sysctls initialization from tcp_sk_init to igmp_net_init. This
function is only called as part of per-namespace initialization, only if
CONFIG_IP_MULTICAST is defined, otherwise igmp_mc_init() call in ip_init is
compiled out, casuing the igmp pernet ops to not be registerd and those sysctl
being left initialized with 0. However, there are certain functions, such as
ip_mc_join_group which are always compiled and make use of some of those
sysctls. Let's do a partial revert of the aforementioned commit and move the
sysctl initialization into inet_init_net, that way they will always have
sane values.

Fixes: dcd87999 ("igmp: net: Move igmp namespace init to correct file")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=196595Reported-by: NGerardo Exequiel Pozzi <vmlinuz386@gmail.com>
Signed-off-by: NNikolay Borisov <nborisov@suse.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

skb_warn_bad_offload triggers a warning when an skb enters the GSO
stack at __skb_gso_segment that does not have CHECKSUM_PARTIAL
checksum offload set.

Commit b2504a5d ("net: reduce skb_warn_bad_offload() noise")
observed that SKB_GSO_DODGY producers can trigger the check and
that passing those packets through the GSO handlers will fix it
up. But, the software UFO handler will set ip_summed to
CHECKSUM_NONE.

When __skb_gso_segment is called from the receive path, this
triggers the warning again.

Make UFO set CHECKSUM_UNNECESSARY instead of CHECKSUM_NONE. On
Tx these two are equivalent. On Rx, this better matches the
skb state (checksum computed), as CHECKSUM_NONE here means no
checksum computed.

See also this thread for context:
http://patchwork.ozlabs.org/patch/799015/

Fixes: b2504a5d ("net: reduce skb_warn_bad_offload() noise")
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

With new TCP_FASTOPEN_CONNECT socket option, there is a possibility
to call tcp_connect() while socket sk_dst_cache is either NULL
or invalid.

 +0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 4
 +0 fcntl(4, F_SETFL, O_RDWR|O_NONBLOCK) = 0
 +0 setsockopt(4, SOL_TCP, TCP_FASTOPEN_CONNECT, [1], 4) = 0
 +0 connect(4, ..., ...) = 0

<< sk->sk_dst_cache becomes obsolete, or even set to NULL >>

 +1 sendto(4, ..., 1000, MSG_FASTOPEN, ..., ...) = 1000

We need to refresh the route otherwise bad things can happen,
especially when syzkaller is running on the host :/

Fixes: 19f6d3f3 ("net/tcp-fastopen: Add new API support")
Reported-by: NDmitry Vyukov <dvyukov@google.com>
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: Wei Wang <weiwan@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Acked-by: NWei Wang <weiwan@google.com>
Acked-by: NYuchung Cheng <ycheng@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fix a TCP loss recovery performance bug raised recently on the netdev
list, in two threads:

(i)  July 26, 2017: netdev thread "TCP fast retransmit issues"
(ii) July 26, 2017: netdev thread:
     "[PATCH V2 net-next] TLP: Don't reschedule PTO when there's one
     outstanding TLP retransmission"

The basic problem is that incoming TCP packets that did not indicate
forward progress could cause the xmit timer (TLP or RTO) to be rearmed
and pushed back in time. In certain corner cases this could result in
the following problems noted in these threads:

 - Repeated ACKs coming in with bogus SACKs corrupted by middleboxes
   could cause TCP to repeatedly schedule TLPs forever. We kept
   sending TLPs after every ~200ms, which elicited bogus SACKs, which
   caused more TLPs, ad infinitum; we never fired an RTO to fill in
   the holes.

 - Incoming data segments could, in some cases, cause us to reschedule
   our RTO or TLP timer further out in time, for no good reason. This
   could cause repeated inbound data to result in stalls in outbound
   data, in the presence of packet loss.

This commit fixes these bugs by changing the TLP and RTO ACK
processing to:

 (a) Only reschedule the xmit timer once per ACK.

 (b) Only reschedule the xmit timer if tcp_clean_rtx_queue() deems the
     ACK indicates sufficient forward progress (a packet was
     cumulatively ACKed, or we got a SACK for a packet that was sent
     before the most recent retransmit of the write queue head).

This brings us back into closer compliance with the RFCs, since, as
the comment for tcp_rearm_rto() notes, we should only restart the RTO
timer after forward progress on the connection. Previously we were
restarting the xmit timer even in these cases where there was no
forward progress.

As a side benefit, this commit simplifies and speeds up the TCP timer
arming logic. We had been calling inet_csk_reset_xmit_timer() three
times on normal ACKs that cumulatively acknowledged some data:

1) Once near the top of tcp_ack() to switch from TLP timer to RTO:
        if (icsk->icsk_pending == ICSK_TIME_LOSS_PROBE)
               tcp_rearm_rto(sk);

2) Once in tcp_clean_rtx_queue(), to update the RTO:
        if (flag & FLAG_ACKED) {
               tcp_rearm_rto(sk);

3) Once in tcp_ack() after tcp_fastretrans_alert() to switch from RTO
   to TLP:
        if (icsk->icsk_pending == ICSK_TIME_RETRANS)
               tcp_schedule_loss_probe(sk);

This commit, by only rescheduling the xmit timer once per ACK,
simplifies the code and reduces CPU overhead.

This commit was tested in an A/B test with Google web server
traffic. SNMP stats and request latency metrics were within noise
levels, substantiating that for normal web traffic patterns this is a
rare issue. This commit was also tested with packetdrill tests to
verify that it fixes the timer behavior in the corner cases discussed
in the netdev threads mentioned above.

This patch is a bug fix patch intended to be queued for -stable
relases.

Fixes: 6ba8a3b1 ("tcp: Tail loss probe (TLP)")
Reported-by: NKlavs Klavsen <kl@vsen.dk>
Reported-by: NMao Wenan <maowenan@huawei.com>
Signed-off-by: NNeal Cardwell <ncardwell@google.com>
Signed-off-by: NYuchung Cheng <ycheng@google.com>
Signed-off-by: NNandita Dukkipati <nanditad@google.com>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Have tcp_schedule_loss_probe() base the TLP scheduling decision based
on when the RTO *should* fire. This is to enable the upcoming xmit
timer fix in this series, where tcp_schedule_loss_probe() cannot
assume that the last timer installed was an RTO timer (because we are
no longer doing the "rearm RTO, rearm RTO, rearm TLP" dance on every
ACK). So tcp_schedule_loss_probe() must independently figure out when
an RTO would want to fire.

In the new TLP implementation following in this series, we cannot
assume that icsk_timeout was set based on an RTO; after processing a
cumulative ACK the icsk_timeout we see can be from a previous TLP or
RTO. So we need to independently recalculate the RTO time (instead of
reading it out of icsk_timeout). Removing this dependency on the
nature of icsk_timeout makes things a little easier to reason about
anyway.

Note that the old and new code should be equivalent, since they are
both saying: "if the RTO is in the future, but at an earlier time than
the normal TLP time, then set the TLP timer to fire when the RTO would
have fired".

Fixes: 6ba8a3b1 ("tcp: Tail loss probe (TLP)")
Signed-off-by: NNeal Cardwell <ncardwell@google.com>
Signed-off-by: NYuchung Cheng <ycheng@google.com>
Signed-off-by: NNandita Dukkipati <nanditad@google.com>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Pure refactor. This helper will be required in the xmit timer fix
later in the patch series. (Because the TLP logic will want to make
this calculation.)

Fixes: 6ba8a3b1 ("tcp: Tail loss probe (TLP)")
Signed-off-by: NNeal Cardwell <ncardwell@google.com>
Signed-off-by: NYuchung Cheng <ycheng@google.com>
Signed-off-by: NNandita Dukkipati <nanditad@google.com>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

syzkaller was able to trigger a divide by 0 in TCP stack [1]

Issue here is that keepalive timer needs to be updated to not attempt
to send a probe if the connection setup was deferred using
TCP_FASTOPEN_CONNECT socket option added in linux-4.11

[1]
 divide error: 0000 [#1] SMP
 CPU: 18 PID: 0 Comm: swapper/18 Not tainted
 task: ffff986f62f4b040 ti: ffff986f62fa2000 task.ti: ffff986f62fa2000
 RIP: 0010:[<ffffffff8409cc0d>]  [<ffffffff8409cc0d>] __tcp_select_window+0x8d/0x160
 Call Trace:
  <IRQ>
  [<ffffffff8409d951>] tcp_transmit_skb+0x11/0x20
  [<ffffffff8409da21>] tcp_xmit_probe_skb+0xc1/0xe0
  [<ffffffff840a0ee8>] tcp_write_wakeup+0x68/0x160
  [<ffffffff840a151b>] tcp_keepalive_timer+0x17b/0x230
  [<ffffffff83b3f799>] call_timer_fn+0x39/0xf0
  [<ffffffff83b40797>] run_timer_softirq+0x1d7/0x280
  [<ffffffff83a04ddb>] __do_softirq+0xcb/0x257
  [<ffffffff83ae03ac>] irq_exit+0x9c/0xb0
  [<ffffffff83a04c1a>] smp_apic_timer_interrupt+0x6a/0x80
  [<ffffffff83a03eaf>] apic_timer_interrupt+0x7f/0x90
  <EOI>
  [<ffffffff83fed2ea>] ? cpuidle_enter_state+0x13a/0x3b0
  [<ffffffff83fed2cd>] ? cpuidle_enter_state+0x11d/0x3b0

Tested:

Following packetdrill no longer crashes the kernel

`echo 0 >/proc/sys/net/ipv4/tcp_timestamps`

// Cache warmup: send a Fast Open cookie request
    0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3
   +0 fcntl(3, F_SETFL, O_RDWR|O_NONBLOCK) = 0
   +0 setsockopt(3, SOL_TCP, TCP_FASTOPEN_CONNECT, [1], 4) = 0
   +0 connect(3, ..., ...) = -1 EINPROGRESS (Operation is now in progress)
   +0 > S 0:0(0) <mss 1460,nop,nop,sackOK,nop,wscale 8,FO,nop,nop>
 +.01 < S. 123:123(0) ack 1 win 14600 <mss 1460,nop,nop,sackOK,nop,wscale 6,FO abcd1234,nop,nop>
   +0 > . 1:1(0) ack 1
   +0 close(3) = 0
   +0 > F. 1:1(0) ack 1
   +0 < F. 1:1(0) ack 2 win 92
   +0 > .  2:2(0) ack 2

   +0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 4
   +0 fcntl(4, F_SETFL, O_RDWR|O_NONBLOCK) = 0
   +0 setsockopt(4, SOL_TCP, TCP_FASTOPEN_CONNECT, [1], 4) = 0
   +0 setsockopt(4, SOL_SOCKET, SO_KEEPALIVE, [1], 4) = 0
 +.01 connect(4, ..., ...) = 0
   +0 setsockopt(4, SOL_TCP, TCP_KEEPIDLE, [5], 4) = 0
   +10 close(4) = 0

`echo 1 >/proc/sys/net/ipv4/tcp_timestamps`

Fixes: 19f6d3f3 ("net/tcp-fastopen: Add new API support")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Reported-by: NDmitry Vyukov <dvyukov@google.com>
Cc: Wei Wang <weiwan@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If the sender switches the congestion control during ECN-triggered
cwnd-reduction state (CA_CWR), upon exiting recovery cwnd is set to
the ssthresh value calculated by the previous congestion control. If
the previous congestion control is BBR that always keep ssthresh
to TCP_INIFINITE_SSTHRESH, cwnd ends up being infinite. The safe
step is to avoid assigning invalid ssthresh value when recovery ends.
Signed-off-by: NYuchung Cheng <ycheng@google.com>
Signed-off-by: NNeal Cardwell <ncardwell@google.com>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In the case that GRO is turned on and the original received packet is
CHECKSUM_PARTIAL, if the outer UDP header is exactly at the last
csum-unnecessary point, which for instance could occur if the packet
comes from another Linux guest on the same Linux host, we have to do
either remcsum_adjust or set up CHECKSUM_PARTIAL again with its
csum_start properly reset considering RCO.

However, since b7fe10e5 ("gro: Fix remcsum offload to deal with frags
in GRO") that barrier in such case could be skipped if GRO turned on,
hence we pass over it and the inner L4 validation mistakenly reckons
it as a bad csum.

This patch makes remcsum_offload being reset at the same time of GRO
remcsum cleanup, so as to make it work in such case as before.

Fixes: b7fe10e5 ("gro: Fix remcsum offload to deal with frags in GRO")
Signed-off-by: NKoichiro Den <den@klaipeden.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

in for(),if((optlen > 0) && (optptr[1] == 0)), enter infinite loop.

Test: receive a packet which the ip length > 20 and the first byte of ip option is 0, produce this issue
Signed-off-by: Nyujuan.qi <yujuan.qi@mediatek.com>
Acked-by: NPaul Moore <paul@paul-moore.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Michał reported a NULL pointer deref during fib_sync_down_dev() when
unregistering a netdevice. The problem is that we don't check for
'in_dev' being NULL, which can happen in very specific cases.

Usually routes are flushed upon NETDEV_DOWN sent in either the netdev or
the inetaddr notification chains. However, if an interface isn't
configured with any IP address, then it's possible for host routes to be
flushed following NETDEV_UNREGISTER, after NULLing dev->ip_ptr in
inetdev_destroy().

To reproduce:
$ ip link add type dummy
$ ip route add local 1.1.1.0/24 dev dummy0
$ ip link del dev dummy0

Fix this by checking for the presence of 'in_dev' before referencing it.

Fixes: 982acb97 ("ipv4: fib: Notify about nexthop status changes")
Signed-off-by: NIdo Schimmel <idosch@mellanox.com>
Reported-by: NMichał Mirosław <mirq-linux@rere.qmqm.pl>
Tested-by: NMichał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When using CONFIG_UBSAN_SANITIZE_ALL, the TCP code produces a
false-positive warning:

net/ipv4/tcp_output.c: In function 'tcp_connect':
net/ipv4/tcp_output.c:2207:40: error: array subscript is below array bounds [-Werror=array-bounds]
   tp->chrono_stat[tp->chrono_type - 1] += now - tp->chrono_start;
                                        ^~
net/ipv4/tcp_output.c:2207:40: error: array subscript is below array bounds [-Werror=array-bounds]
   tp->chrono_stat[tp->chrono_type - 1] += now - tp->chrono_start;
   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

I have opened a gcc bug for this, but distros have already shipped
compilers with this problem, and it's not clear yet whether there is
a way for gcc to avoid the warning. As the problem is related to the
bitfield access, this introduces a temporary variable to store the old
enum value.

I did not notice this warning earlier, since UBSAN is disabled when
building with COMPILE_TEST, and that was always turned on in both
allmodconfig and randconfig tests.

Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81601Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When an early demuxed packet reaches __udp6_lib_lookup_skb(), the
sk reference is retrieved and used, but the relevant reference
count is leaked and the socket destructor is never called.
Beyond leaking the sk memory, if there are pending UDP packets
in the receive queue, even the related accounted memory is leaked.

In the long run, this will cause persistent forward allocation errors
and no UDP skbs (both ipv4 and ipv6) will be able to reach the
user-space.

Fix this by explicitly accessing the early demux reference before
the lookup, and properly decreasing the socket reference count
after usage.

Also drop the skb_steal_sock() in __udp6_lib_lookup_skb(), and
the now obsoleted comment about "socket cache".

The newly added code is derived from the current ipv4 code for the
similar path.

v1 -> v2:
  fixed the __udp6_lib_rcv() return code for resubmission,
  as suggested by Eric
Reported-by: NSam Edwards <CFSworks@gmail.com>
Reported-by: NMarc Haber <mh+netdev@zugschlus.de>
Fixes: 5425077d ("net: ipv6: Add early demux handler for UDP unicast")
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We must use pre-processor conditional block or suitable accessors to
manipulate skb->sp elsewhere builds lacking the CONFIG_XFRM will break.

Fixes: dce4551c ("udp: preserve head state for IP_CMSG_PASSSEC")
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Paul Moore reported a SELinux/IP_PASSSEC regression
caused by missing skb->sp at recvmsg() time. We need to
preserve the skb head state to process the IP_CMSG_PASSSEC
cmsg.

With this commit we avoid releasing the skb head state in the
BH even if a secpath is attached to the current skb, and stores
the skb status (with/without head states) in the scratch area,
so that we can access it at skb deallocation time, without
incurring in cache-miss penalties.

This also avoids misusing the skb CB for ipv6 packets,
as introduced by the commit 0ddf3fb2 ("udp: preserve
skb->dst if required for IP options processing").

Clean a bit the scratch area helpers implementation, to
reduce the code differences between 32 and 64 bits build.
Reported-by: NPaul Moore <paul@paul-moore.com>
Fixes: 0a463c78 ("udp: avoid a cache miss on dequeue")
Fixes: 0ddf3fb2 ("udp: preserve skb->dst if required for IP options processing")
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Tested-by: NPaul Moore <paul@paul-moore.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Net stack initialization currently initializes fib-trie after the
first call to netdevice_notifier() call. In fact fib_trie initialization
needs to happen before first rtnl_register(). It does not cause any problem
since there are no devices UP at this moment, but trying to bring 'lo'
UP at initialization would make this assumption wrong and exposes the issue.

Fixes following crash

 Call Trace:
  ? alternate_node_alloc+0x76/0xa0
  fib_table_insert+0x1b7/0x4b0
  fib_magic.isra.17+0xea/0x120
  fib_add_ifaddr+0x7b/0x190
  fib_netdev_event+0xc0/0x130
  register_netdevice_notifier+0x1c1/0x1d0
  ip_fib_init+0x72/0x85
  ip_rt_init+0x187/0x1e9
  ip_init+0xe/0x1a
  inet_init+0x171/0x26c
  ? ipv4_offload_init+0x66/0x66
  do_one_initcall+0x43/0x160
  kernel_init_freeable+0x191/0x219
  ? rest_init+0x80/0x80
  kernel_init+0xe/0x150
  ret_from_fork+0x22/0x30
 Code: f6 46 23 04 74 86 4c 89 f7 e8 ae 45 01 00 49 89 c7 4d 85 ff 0f 85 7b ff ff ff 31 db eb 08 4c 89 ff e8 16 47 01 00 48 8b 44 24 38 <45> 8b 6e 14 4d 63 76 74 48 89 04 24 0f 1f 44 00 00 48 83 c4 08
 RIP: kmem_cache_alloc+0xcf/0x1c0 RSP: ffff9b1500017c28
 CR2: 0000000000000014

Fixes: 7b1a74fd ("[NETNS]: Refactor fib initialization so it can handle multiple namespaces.")
Fixes: 7f9b8052 ("[IPV4]: fib hash|trie initialization")
Signed-off-by: NMahesh Bandewar <maheshb@google.com>
Acked-by: N"Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Eric noticed that in udp_recvmsg() we still need to access
skb->dst while processing the IP options.
Since commit 0a463c78 ("udp: avoid a cache miss on dequeue")
skb->dst is no more available at recvmsg() time and bad things
will happen if we enter the relevant code path.

This commit address the issue, avoid clearing skb->dst if
any IP options are present into the relevant skb.
Since the IP CB is contained in the first skb cacheline, we can
test it to decide to leverage the consume_stateless_skb()
optimization, without measurable additional cost in the faster
path.

v1 -> v2: updated commit message tags

Fixes: 0a463c78 ("udp: avoid a cache miss on dequeue")
Reported-by: NAndrey Konovalov <andreyknvl@google.com>
Reported-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

KMSAN reported use of uninitialized memory in skb_set_hash_from_sk(),
which originated from the TCP request socket created in
cookie_v6_check():

 ==================================================================
 BUG: KMSAN: use of uninitialized memory in tcp_transmit_skb+0xf77/0x3ec0
 CPU: 1 PID: 2949 Comm: syz-execprog Not tainted 4.11.0-rc5+ #2931
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
 TCP: request_sock_TCPv6: Possible SYN flooding on port 20028. Sending cookies.  Check SNMP counters.
 Call Trace:
  <IRQ>
  __dump_stack lib/dump_stack.c:16
  dump_stack+0x172/0x1c0 lib/dump_stack.c:52
  kmsan_report+0x12a/0x180 mm/kmsan/kmsan.c:927
  __msan_warning_32+0x61/0xb0 mm/kmsan/kmsan_instr.c:469
  skb_set_hash_from_sk ./include/net/sock.h:2011
  tcp_transmit_skb+0xf77/0x3ec0 net/ipv4/tcp_output.c:983
  tcp_send_ack+0x75b/0x830 net/ipv4/tcp_output.c:3493
  tcp_delack_timer_handler+0x9a6/0xb90 net/ipv4/tcp_timer.c:284
  tcp_delack_timer+0x1b0/0x310 net/ipv4/tcp_timer.c:309
  call_timer_fn+0x240/0x520 kernel/time/timer.c:1268
  expire_timers kernel/time/timer.c:1307
  __run_timers+0xc13/0xf10 kernel/time/timer.c:1601
  run_timer_softirq+0x36/0xa0 kernel/time/timer.c:1614
  __do_softirq+0x485/0x942 kernel/softirq.c:284
  invoke_softirq kernel/softirq.c:364
  irq_exit+0x1fa/0x230 kernel/softirq.c:405
  exiting_irq+0xe/0x10 ./arch/x86/include/asm/apic.h:657
  smp_apic_timer_interrupt+0x5a/0x80 arch/x86/kernel/apic/apic.c:966
  apic_timer_interrupt+0x86/0x90 arch/x86/entry/entry_64.S:489
 RIP: 0010:native_restore_fl ./arch/x86/include/asm/irqflags.h:36
 RIP: 0010:arch_local_irq_restore ./arch/x86/include/asm/irqflags.h:77
 RIP: 0010:__msan_poison_alloca+0xed/0x120 mm/kmsan/kmsan_instr.c:440
 RSP: 0018:ffff880024917cd8 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff10
 RAX: 0000000000000246 RBX: ffff8800224c0000 RCX: 0000000000000005
 RDX: 0000000000000004 RSI: ffff880000000000 RDI: ffffea0000b6d770
 RBP: ffff880024917d58 R08: 0000000000000dd8 R09: 0000000000000004
 R10: 0000160000000000 R11: 0000000000000000 R12: ffffffff85abf810
 R13: ffff880024917dd8 R14: 0000000000000010 R15: ffffffff81cabde4
  </IRQ>
  poll_select_copy_remaining+0xac/0x6b0 fs/select.c:293
  SYSC_select+0x4b4/0x4e0 fs/select.c:653
  SyS_select+0x76/0xa0 fs/select.c:634
  entry_SYSCALL_64_fastpath+0x13/0x94 arch/x86/entry/entry_64.S:204
 RIP: 0033:0x4597e7
 RSP: 002b:000000c420037ee0 EFLAGS: 00000246 ORIG_RAX: 0000000000000017
 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00000000004597e7
 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
 RBP: 000000c420037ef0 R08: 000000c420037ee0 R09: 0000000000000059
 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000042dc20
 R13: 00000000000000f3 R14: 0000000000000030 R15: 0000000000000003
 chained origin:
  save_stack_trace+0x37/0x40 arch/x86/kernel/stacktrace.c:59
  kmsan_save_stack_with_flags mm/kmsan/kmsan.c:302
  kmsan_save_stack mm/kmsan/kmsan.c:317
  kmsan_internal_chain_origin+0x12a/0x1f0 mm/kmsan/kmsan.c:547
  __msan_store_shadow_origin_4+0xac/0x110 mm/kmsan/kmsan_instr.c:259
  tcp_create_openreq_child+0x709/0x1ae0 net/ipv4/tcp_minisocks.c:472
  tcp_v6_syn_recv_sock+0x7eb/0x2a30 net/ipv6/tcp_ipv6.c:1103
  tcp_get_cookie_sock+0x136/0x5f0 net/ipv4/syncookies.c:212
  cookie_v6_check+0x17a9/0x1b50 net/ipv6/syncookies.c:245
  tcp_v6_cookie_check net/ipv6/tcp_ipv6.c:989
  tcp_v6_do_rcv+0xdd8/0x1c60 net/ipv6/tcp_ipv6.c:1298
  tcp_v6_rcv+0x41a3/0x4f00 net/ipv6/tcp_ipv6.c:1487
  ip6_input_finish+0x82f/0x1ee0 net/ipv6/ip6_input.c:279
  NF_HOOK ./include/linux/netfilter.h:257
  ip6_input+0x239/0x290 net/ipv6/ip6_input.c:322
  dst_input ./include/net/dst.h:492
  ip6_rcv_finish net/ipv6/ip6_input.c:69
  NF_HOOK ./include/linux/netfilter.h:257
  ipv6_rcv+0x1dbd/0x22e0 net/ipv6/ip6_input.c:203
  __netif_receive_skb_core+0x2f6f/0x3a20 net/core/dev.c:4208
  __netif_receive_skb net/core/dev.c:4246
  process_backlog+0x667/0xba0 net/core/dev.c:4866
  napi_poll net/core/dev.c:5268
  net_rx_action+0xc95/0x1590 net/core/dev.c:5333
  __do_softirq+0x485/0x942 kernel/softirq.c:284
 origin:
  save_stack_trace+0x37/0x40 arch/x86/kernel/stacktrace.c:59
  kmsan_save_stack_with_flags mm/kmsan/kmsan.c:302
  kmsan_internal_poison_shadow+0xb1/0x1a0 mm/kmsan/kmsan.c:198
  kmsan_kmalloc+0x7f/0xe0 mm/kmsan/kmsan.c:337
  kmem_cache_alloc+0x1c2/0x1e0 mm/slub.c:2766
  reqsk_alloc ./include/net/request_sock.h:87
  inet_reqsk_alloc+0xa4/0x5b0 net/ipv4/tcp_input.c:6200
  cookie_v6_check+0x4f4/0x1b50 net/ipv6/syncookies.c:169
  tcp_v6_cookie_check net/ipv6/tcp_ipv6.c:989
  tcp_v6_do_rcv+0xdd8/0x1c60 net/ipv6/tcp_ipv6.c:1298
  tcp_v6_rcv+0x41a3/0x4f00 net/ipv6/tcp_ipv6.c:1487
  ip6_input_finish+0x82f/0x1ee0 net/ipv6/ip6_input.c:279
  NF_HOOK ./include/linux/netfilter.h:257
  ip6_input+0x239/0x290 net/ipv6/ip6_input.c:322
  dst_input ./include/net/dst.h:492
  ip6_rcv_finish net/ipv6/ip6_input.c:69
  NF_HOOK ./include/linux/netfilter.h:257
  ipv6_rcv+0x1dbd/0x22e0 net/ipv6/ip6_input.c:203
  __netif_receive_skb_core+0x2f6f/0x3a20 net/core/dev.c:4208
  __netif_receive_skb net/core/dev.c:4246
  process_backlog+0x667/0xba0 net/core/dev.c:4866
  napi_poll net/core/dev.c:5268
  net_rx_action+0xc95/0x1590 net/core/dev.c:5333
  __do_softirq+0x485/0x942 kernel/softirq.c:284
 ==================================================================

Similar error is reported for cookie_v4_check().

Fixes: 58d607d3 ("tcp: provide skb->hash to synack packets")
Signed-off-by: NAlexander Potapenko <glider@google.com>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

arp packets cannot be forwarded.

They can be bridged, but then they can be filtered using
either ebtables or nftables bridge family.

The bridge netfilter exposes a "call-arptables" switch which
pushes packets into arptables, but lets not expose this for nftables, so better
close this asap.
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

Fixes the following behavior: for connections that had no RTT sample
at the time of initializing congestion control, BBR was initializing
the pacing rate to a high nominal rate (based an a guess of RTT=1ms,
in case this is LAN traffic). Then BBR never adjusted the pacing rate
downward upon obtaining an actual RTT sample, if the connection never
filled the pipe (e.g. all sends were small app-limited writes()).

This fix adjusts the pacing rate upon obtaining the first RTT sample.

Fixes: 0f8782ea ("tcp_bbr: add BBR congestion control")
Signed-off-by: NNeal Cardwell <ncardwell@google.com>
Signed-off-by: NYuchung Cheng <ycheng@google.com>
Signed-off-by: NSoheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fix a corner case noticed by Eric Dumazet, where BBR's setting
sk->sk_pacing_rate to 0 during initialization could theoretically
cause packets in the sending host to hang if there were packets "in
flight" in the pacing infrastructure at the time the BBR congestion
control state is initialized. This could occur if the pacing
infrastructure happened to race with bbr_init() in a way such that the
pacer read the 0 rather than the immediately following non-zero pacing
rate.

Fixes: 0f8782ea ("tcp_bbr: add BBR congestion control")
Reported-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NNeal Cardwell <ncardwell@google.com>
Signed-off-by: NYuchung Cheng <ycheng@google.com>
Signed-off-by: NSoheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Introduce a helper to initialize the BBR pacing rate unconditionally,
based on the current cwnd and RTT estimate. This is a pure refactor,
but is needed for two following fixes.

Fixes: 0f8782ea ("tcp_bbr: add BBR congestion control")
Signed-off-by: NNeal Cardwell <ncardwell@google.com>
Signed-off-by: NYuchung Cheng <ycheng@google.com>
Signed-off-by: NSoheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Introduce a helper to convert a BBR bandwidth and gain factor to a
pacing rate in bytes per second. This is a pure refactor, but is
needed for two following fixes.

Fixes: 0f8782ea ("tcp_bbr: add BBR congestion control")
Signed-off-by: NNeal Cardwell <ncardwell@google.com>
Signed-off-by: NYuchung Cheng <ycheng@google.com>
Signed-off-by: NSoheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In bbr_set_pacing_rate(), which decides whether to cut the pacing
rate, there was some code that considered exiting STARTUP to be
equivalent to the notion of filling the pipe (i.e.,
bbr_full_bw_reached()). Specifically, as the code was structured,
exiting STARTUP and going into PROBE_RTT could cause us to cut the
pacing rate down to something silly and low, based on whatever
bandwidth samples we've had so far, when it's possible that all of
them have been small app-limited bandwidth samples that are not
representative of the bandwidth available in the path. (The code was
correct at the time it was written, but the state machine changed
without this spot being adjusted correspondingly.)

Fixes: 0f8782ea ("tcp_bbr: add BBR congestion control")
Signed-off-by: NNeal Cardwell <ncardwell@google.com>
Signed-off-by: NYuchung Cheng <ycheng@google.com>
Signed-off-by: NSoheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Some time ago David Woodhouse reported skb_under_panic
when we try to push ethernet header to fragmented ipv6 skbs.
It was fixed for ipv6 by Florian Westphal in
commit 1d325d21 ("ipv6: ip6_fragment: fix headroom tests and skb leak")

However similar problem still exist in ipv4.

It does not trigger skb_under_panic due paranoid check
in ip_finish_output2, however according to Alexey Kuznetsov
current state is abnormal and ip_fragment should be fixed too.
Signed-off-by: NVasily Averin <vvs@virtuozzo.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The ipmr_get_table() function doesn't return error pointers it returns
NULL on error.

Fixes: 4f75ba69 ("net: ipmr: Add ipmr_rtm_getroute")
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Acked-by: NNikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fixes: 6797318e ("tcp: md5: add an address prefix for key lookup")
Signed-off-by: NFengguang Wu <fengguang.wu@intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

fix rtm policy name typo in mpls_getroute and also remove
export of rtm_ipv4_policy

Fixes: 397fc9e5 ("mpls: route get support")
Reported-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NRoopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The MPLS code now needs it.

Fixes: 397fc9e5 ("mpls: route get support")
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

SYN-ACK responses on a server in response to a SYN from a client
did not get the injected skb mark that was tagged on the SYN packet.

Fixes: 84f39b08 ("net: support marking accepting TCP sockets")
Reviewed-by: NLorenzo Colitti <lorenzo@google.com>
Signed-off-by: NJamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.
Signed-off-by: NElena Reshetova <elena.reshetova@intel.com>
Signed-off-by: NHans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NDavid Windsor <dwindsor@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.
Signed-off-by: NElena Reshetova <elena.reshetova@intel.com>
Signed-off-by: NHans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NDavid Windsor <dwindsor@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

sk_ehashfn() is only used from a single file.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Added support for changing congestion control for SOCK_OPS bpf
programs through the setsockopt bpf helper function. It also adds
a new SOCK_OPS op, BPF_SOCK_OPS_NEEDS_ECN, that is needed for
congestion controls, like dctcp, that need to enable ECN in the
SYN packets.
Signed-off-by: NLawrence Brakmo <brakmo@fb.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Added callbacks to BPF SOCK_OPS type program before an active
connection is intialized and after a passive or active connection is
established.

The following patch demostrates how they can be used to set send and
receive buffer sizes.
Signed-off-by: NLawrence Brakmo <brakmo@fb.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch adds suppport for setting the initial advertized window from
within a BPF_SOCK_OPS program. This can be used to support larger
initial cwnd values in environments where it is known to be safe.
Signed-off-by: NLawrence Brakmo <brakmo@fb.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch adds support for setting a per connection SYN and
SYN_ACK RTOs from within a BPF_SOCK_OPS program. For example,
to set small RTOs when it is known both hosts are within a
datacenter.
Signed-off-by: NLawrence Brakmo <brakmo@fb.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.
Signed-off-by: NElena Reshetova <elena.reshetova@intel.com>
Signed-off-by: NHans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NDavid Windsor <dwindsor@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>