ipv4_pdp_add() is called in RCU read-side critical section.
So GFP_KERNEL should not be used in the function.
This patch make ipv4_pdp_add() to use GFP_ATOMIC instead of GFP_KERNEL.

Test commands:
gtp-link add gtp1 &
gtp-tunnel add gtp1 v1 100 200 1.1.1.1 2.2.2.2

Splat looks like:
[  130.618881] =============================
[  130.626382] WARNING: suspicious RCU usage
[  130.626994] 5.2.0-rc6+ #50 Not tainted
[  130.627622] -----------------------------
[  130.628223] ./include/linux/rcupdate.h:266 Illegal context switch in RCU read-side critical section!
[  130.629684]
[  130.629684] other info that might help us debug this:
[  130.629684]
[  130.631022]
[  130.631022] rcu_scheduler_active = 2, debug_locks = 1
[  130.632136] 4 locks held by gtp-tunnel/1025:
[  130.632925]  #0: 000000002b93c8b7 (cb_lock){++++}, at: genl_rcv+0x15/0x40
[  130.634159]  #1: 00000000f17bc999 (genl_mutex){+.+.}, at: genl_rcv_msg+0xfb/0x130
[  130.635487]  #2: 00000000c644ed8e (rtnl_mutex){+.+.}, at: gtp_genl_new_pdp+0x18c/0x1150 [gtp]
[  130.636936]  #3: 0000000007a1cde7 (rcu_read_lock){....}, at: gtp_genl_new_pdp+0x187/0x1150 [gtp]
[  130.638348]
[  130.638348] stack backtrace:
[  130.639062] CPU: 1 PID: 1025 Comm: gtp-tunnel Not tainted 5.2.0-rc6+ #50
[  130.641318] Call Trace:
[  130.641707]  dump_stack+0x7c/0xbb
[  130.642252]  ___might_sleep+0x2c0/0x3b0
[  130.642862]  kmem_cache_alloc_trace+0x1cd/0x2b0
[  130.643591]  gtp_genl_new_pdp+0x6c5/0x1150 [gtp]
[  130.644371]  genl_family_rcv_msg+0x63a/0x1030
[  130.645074]  ? mutex_lock_io_nested+0x1090/0x1090
[  130.645845]  ? genl_unregister_family+0x630/0x630
[  130.646592]  ? debug_show_all_locks+0x2d0/0x2d0
[  130.647293]  ? check_flags.part.40+0x440/0x440
[  130.648099]  genl_rcv_msg+0xa3/0x130
[ ... ]

Fixes: 459aa660 ("gtp: add initial driver for datapath of GPRS Tunneling Protocol (GTP-U)")
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

gtp_encap_disable() in gtp_dellink() is unnecessary because it will be
called by unregister_netdevice().
unregister_netdevice() internally calls gtp_dev_uninit() by ->ndo_uninit().
And gtp_dev_uninit() calls gtp_encap_disable().
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

gtp_encap_destroy() is called twice.
1. When interface is deleted.
2. When udp socket is destroyed.
either gtp->sk0 or gtp->sk1u could be freed by sock_put() in
gtp_encap_destroy(). so, when gtp_encap_destroy() is called again,
it would uses freed sk pointer.

patch makes gtp_encap_destroy() to set either gtp->sk0 or gtp->sk1u to
null. in addition, both gtp->sk0 and gtp->sk1u pointer are protected
by rtnl_lock. so, rtnl_lock() is added.

Test command:
   gtp-link add gtp1 &
   killall gtp-link
   ip link del gtp1

Splat looks like:
[   83.182767] BUG: KASAN: use-after-free in __lock_acquire+0x3a20/0x46a0
[   83.184128] Read of size 8 at addr ffff8880cc7d5360 by task ip/1008
[   83.185567] CPU: 1 PID: 1008 Comm: ip Not tainted 5.2.0-rc6+ #50
[   83.188469] Call Trace:
[ ... ]
[   83.200126]  lock_acquire+0x141/0x380
[   83.200575]  ? lock_sock_nested+0x3a/0xf0
[   83.201069]  _raw_spin_lock_bh+0x38/0x70
[   83.201551]  ? lock_sock_nested+0x3a/0xf0
[   83.202044]  lock_sock_nested+0x3a/0xf0
[   83.202520]  gtp_encap_destroy+0x18/0xe0 [gtp]
[   83.203065]  gtp_encap_disable.isra.14+0x13/0x50 [gtp]
[   83.203687]  gtp_dellink+0x56/0x170 [gtp]
[   83.204190]  rtnl_delete_link+0xb4/0x100
[ ... ]
[   83.236513] Allocated by task 976:
[   83.236925]  save_stack+0x19/0x80
[   83.237332]  __kasan_kmalloc.constprop.3+0xa0/0xd0
[   83.237894]  kmem_cache_alloc+0xd8/0x280
[   83.238360]  sk_prot_alloc.isra.42+0x50/0x200
[   83.238874]  sk_alloc+0x32/0x940
[   83.239264]  inet_create+0x283/0xc20
[   83.239684]  __sock_create+0x2dd/0x540
[   83.240136]  __sys_socket+0xca/0x1a0
[   83.240550]  __x64_sys_socket+0x6f/0xb0
[   83.240998]  do_syscall_64+0x9c/0x450
[   83.241466]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
[   83.242061]
[   83.242249] Freed by task 0:
[   83.242616]  save_stack+0x19/0x80
[   83.243013]  __kasan_slab_free+0x111/0x150
[   83.243498]  kmem_cache_free+0x89/0x250
[   83.244444]  __sk_destruct+0x38f/0x5a0
[   83.245366]  rcu_core+0x7e9/0x1c20
[   83.245766]  __do_softirq+0x213/0x8fa

Fixes: 1e3a3abd ("gtp: make GTP sockets in gtp_newlink optional")
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

gtp_encap_enable_socket() and gtp_encap_destroy() are not protected
by rcu_read_lock(). and it's not safe to write sk->sk_user_data.
This patch make these functions to use lock_sock() instead of
rcu_dereference_sk_user_data().

Test commands:
    gtp-link add gtp1

Splat looks like:
[   83.238315] =============================
[   83.239127] WARNING: suspicious RCU usage
[   83.239702] 5.2.0-rc6+ #49 Not tainted
[   83.240268] -----------------------------
[   83.241205] drivers/net/gtp.c:799 suspicious rcu_dereference_check() usage!
[   83.243828]
[   83.243828] other info that might help us debug this:
[   83.243828]
[   83.246325]
[   83.246325] rcu_scheduler_active = 2, debug_locks = 1
[   83.247314] 1 lock held by gtp-link/1008:
[   83.248523]  #0: 0000000017772c7f (rtnl_mutex){+.+.}, at: __rtnl_newlink+0x5f5/0x11b0
[   83.251503]
[   83.251503] stack backtrace:
[   83.252173] CPU: 0 PID: 1008 Comm: gtp-link Not tainted 5.2.0-rc6+ #49
[   83.253271] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
[   83.254562] Call Trace:
[   83.254995]  dump_stack+0x7c/0xbb
[   83.255567]  gtp_encap_enable_socket+0x2df/0x360 [gtp]
[   83.256415]  ? gtp_find_dev+0x1a0/0x1a0 [gtp]
[   83.257161]  ? memset+0x1f/0x40
[   83.257843]  gtp_newlink+0x90/0xa21 [gtp]
[   83.258497]  ? __netlink_ns_capable+0xc3/0xf0
[   83.259260]  __rtnl_newlink+0xb9f/0x11b0
[   83.260022]  ? rtnl_link_unregister+0x230/0x230
[ ... ]

Fixes: 1e3a3abd ("gtp: make GTP sockets in gtp_newlink optional")
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Jakub Kicinski says:

====================
net/tls: fix poll() wake up

This small fix + selftest series is very similar to the previous
commit 04b25a54 ("net/tls: fix no wakeup on partial reads").
This time instead of recvmsg we're fixing poll wake up.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Add a test which checks if leftover record data in TLS
layer correctly wakes up poll().
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

David reports that RPC applications which use epoll() occasionally
get stuck, and that TLS ULP causes the kernel to not wake applications,
even though read() will return data.

This is indeed true. The ctx->rx_list which holds partially copied
records is not consulted when deciding whether socket is readable.

Note that SO_RCVLOWAT with epoll() is and has always been broken for
kernel TLS. We'd need to parse all records from the TCP layer, instead
of just the first one.

Fixes: 692d7b5d ("tls: Fix recvmsg() to be able to peek across multiple records")
Reported-by: David Beckett <david.beckett@netronome.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Both ip_neigh_gw4() and ip_neigh_gw6() can return either a valid pointer
or an error pointer, but the code currently checks that the pointer is
not NULL.

Fix this by checking that the pointer is not an error pointer, as this
can result in a NULL pointer dereference [1]. Specifically, I believe
that what happened is that ip_neigh_gw4() returned '-EINVAL'
(0xffffffffffffffea) to which the offset of 'refcnt' (0x70) was added,
which resulted in the address 0x000000000000005a.

[1]
 BUG: KASAN: null-ptr-deref in refcount_inc_not_zero_checked+0x6e/0x180
 Read of size 4 at addr 000000000000005a by task swapper/2/0

 CPU: 2 PID: 0 Comm: swapper/2 Not tainted 5.2.0-rc6-custom-reg-179657-gaa32d89 #396
 Hardware name: Mellanox Technologies Ltd. MSN2010/SA002610, BIOS 5.6.5 08/24/2017
 Call Trace:
 <IRQ>
 dump_stack+0x73/0xbb
 __kasan_report+0x188/0x1ea
 kasan_report+0xe/0x20
 refcount_inc_not_zero_checked+0x6e/0x180
 ipv4_neigh_lookup+0x365/0x12c0
 __neigh_update+0x1467/0x22f0
 arp_process.constprop.6+0x82e/0x1f00
 __netif_receive_skb_one_core+0xee/0x170
 process_backlog+0xe3/0x640
 net_rx_action+0x755/0xd90
 __do_softirq+0x29b/0xae7
 irq_exit+0x177/0x1c0
 smp_apic_timer_interrupt+0x164/0x5e0
 apic_timer_interrupt+0xf/0x20
 </IRQ>

Fixes: 5c9f7c1d ("ipv4: Add helpers for neigh lookup for nexthop")
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reported-by: Shalom Toledo <shalomt@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Set the flag of RTL8152_UNPLUG if and only if the device is unplugged.
Some error codes sometimes don't mean the real disconnection of usb device.
For those situations, set the flag of RTL8152_UNPLUG causes the driver skips
some flows of disabling the device, and it let the device stay at incorrect
state.
Signed-off-by: Hayes Wang <hayeswang@realtek.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Cong Wang says:

====================
hsr: a few bug fixes

This patchset contains 3 bug fixes for hsr triggered by a syzbot
reproducer, please check each patch for details.
====================
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>

hsr_port_get_hsr() could return NULL and kernel
could crash:

 BUG: kernel NULL pointer dereference, address: 0000000000000010
 #PF: supervisor read access in kernel mode
 #PF: error_code(0x0000) - not-present page
 PGD 8000000074b84067 P4D 8000000074b84067 PUD 7057d067 PMD 0
 Oops: 0000 [#1] SMP PTI
 CPU: 0 PID: 754 Comm: a.out Not tainted 5.2.0-rc6+ #718
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-2.fc30 04/01/2014
 RIP: 0010:hsr_dev_xmit+0x20/0x31
 Code: 48 8b 1b eb e0 5b 5d 41 5c c3 66 66 66 66 90 55 48 89 fd 48 8d be 40 0b 00 00 be 04 00 00 00 e8 ee f2 ff ff 48 89 ef 48 89 c6 <48> 8b 40 10 48 89 45 10 e8 6c 1b 00 00 31 c0 5d c3 66 66 66 66 90
 RSP: 0018:ffffb5b400003c48 EFLAGS: 00010246
 RAX: 0000000000000000 RBX: ffff9821b4509a88 RCX: 0000000000000000
 RDX: ffff9821b4509a88 RSI: 0000000000000000 RDI: ffff9821bc3fc7c0
 RBP: ffff9821bc3fc7c0 R08: 0000000000000000 R09: 00000000000c2019
 R10: 0000000000000000 R11: 0000000000000002 R12: ffff9821bc3fc7c0
 R13: ffff9821b4509a88 R14: 0000000000000000 R15: 000000000000006e
 FS:  00007fee112a1800(0000) GS:ffff9821bd800000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 0000000000000010 CR3: 000000006e9ce000 CR4: 00000000000406f0
 Call Trace:
  <IRQ>
  netdev_start_xmit+0x1b/0x38
  dev_hard_start_xmit+0x121/0x21e
  ? validate_xmit_skb.isra.0+0x19/0x1e3
  __dev_queue_xmit+0x74c/0x823
  ? lockdep_hardirqs_on+0x12b/0x17d
  ip6_finish_output2+0x3d3/0x42c
  ? ip6_mtu+0x55/0x5c
  ? mld_sendpack+0x191/0x229
  mld_sendpack+0x191/0x229
  mld_ifc_timer_expire+0x1f7/0x230
  ? mld_dad_timer_expire+0x58/0x58
  call_timer_fn+0x12e/0x273
  __run_timers.part.0+0x174/0x1b5
  ? mld_dad_timer_expire+0x58/0x58
  ? sched_clock_cpu+0x10/0xad
  ? mark_lock+0x26/0x1f2
  ? __lock_is_held+0x40/0x71
  run_timer_softirq+0x26/0x48
  __do_softirq+0x1af/0x392
  irq_exit+0x53/0xa2
  smp_apic_timer_interrupt+0x1c4/0x1d9
  apic_timer_interrupt+0xf/0x20
  </IRQ>

Cc: Arvid Brodin <arvid.brodin@alten.se>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

hsr_link_ops implements ->newlink() but not ->dellink(),
which leads that resources not released after removing the device,
particularly the entries in self_node_db and node_db.

So add ->dellink() implementation to replace the priv_destructor.
This also makes the code slightly easier to understand.

Reported-by: syzbot+c6167ec3de7def23d1e8@syzkaller.appspotmail.com
Cc: Arvid Brodin <arvid.brodin@alten.se>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

hsr_del_port() should release all the resources allocated
in hsr_add_port().

As a consequence of this change, hsr_for_each_port() is no
longer safe to work with hsr_del_port(), switch to
list_for_each_entry_safe() as we always hold RTNL lock.

Cc: Arvid Brodin <arvid.brodin@alten.se>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Steffen Klassert says:

====================
pull request (net): ipsec 2019-07-05

1)  Fix xfrm selector prefix length validation for
    inter address family tunneling.
    From Anirudh Gupta.

2) Fix a memleak in pfkey.
   From Jeremy Sowden.

3) Fix SA selector validation to allow empty selectors again.
   From Nicolas Dichtel.

4) Select crypto ciphers for xfrm_algo, this fixes some
   randconfig builds. From Arnd Bergmann.

5) Remove a duplicated assignment in xfrm_bydst_resize.
   From Cong Wang.

6) Fix a hlist corruption on hash rebuild.
   From Florian Westphal.

7) Fix a memory leak when creating xfrm interfaces.
   From Nicolas Dichtel.

Please pull or let me know if there are problems.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

bond_xmit_roundrobin() checks for IGMP packets but it parses
the IP header even before checking skb->protocol.

We should validate the IP header with pskb_may_pull() before
using iph->protocol.

Reported-and-tested-by: syzbot+e5be16aa39ad6e755391@syzkaller.appspotmail.com
Fixes: a2fd940f ("bonding: fix broken multicast with round-robin mode")
Cc: Jay Vosburgh <j.vosburgh@gmail.com>
Cc: Veaceslav Falico <vfalico@gmail.com>
Cc: Andy Gospodarek <andy@greyhouse.net>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Daniel Borkmann says:

====================
pull-request: bpf 2019-07-03

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

The main changes are:

1) Fix the interpreter to properly handle BPF_ALU32 | BPF_ARSH
   on BE architectures, from Jiong.

2) Fix several bugs in the x32 BPF JIT for handling shifts by 0,
   from Luke and Xi.

3) Fix NULL pointer deref in btf_type_is_resolve_source_only(),
   from Stanislav.

4) Properly handle the check that forwarding is enabled on the device
   in bpf_ipv6_fib_lookup() helper code, from Anton.

5) Fix UAPI bpf_prog_info fields alignment for archs that have 16 bit
   alignment such as m68k, from Baruch.

6) Fix kernel hanging in unregister_netdevice loop while unregistering
   device bound to XDP socket, from Ilya.

7) Properly terminate tail update in xskq_produce_flush_desc(), from Nathan.

8) Fix broken always_inline handling in test_lwt_seg6local, from Jiri.

9) Fix bpftool to use correct argument in cgroup errors, from Jakub.

10) Fix detaching dummy prog in XDP redirect sample code, from Prashant.

11) Add Jonathan to AF_XDP reviewers, from Björn.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

The hip07 chip support vlan TSO, this patch adds NETIF_F_TSO
and NETIF_F_TSO6 flags to vlan_features to improve the
performance after adding vlan to the net ports.
Signed-off-by: Yonglong Liu <liuyonglong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Now all ctrl chunks are counted for asoc stats.octrlchunks and net
SCTP_MIB_OUTCTRLCHUNKS either after queuing up or bundling, other
than the chunk maked and bundled in sctp_packet_bundle_sack, which
caused 'outctrlchunks' not consistent with 'inctrlchunks' in peer.

This issue exists since very beginning, here to fix it by increasing
both net SCTP_MIB_OUTCTRLCHUNKS and asoc stats.octrlchunks when sack
chunk is maked and bundled in sctp_packet_bundle_sack.
Reported-by: Ja Ram Jeon <jajeon@redhat.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

r8153b_rx_agg_chg_indicate() needs to be called after enabling TX/RX and
before calling rxdy_gated_en(tp, false). Otherwise, the change of the
settings of RX aggregation wouldn't work.

Besides, adjust rtl8152_set_coalesce() for the same reason. If
rx_coalesce_usecs is changed, restart TX/RX to let the setting work.
Signed-off-by: Hayes Wang <hayeswang@realtek.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

If IPV6 was disabled, then ss command would cause a kernel warning
because the command was attempting to dump IPV6 socket information.
The fix is to just remove the warning.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=202249
Fixes: 432490f9 ("net: ip, diag -- Add diag interface for raw sockets")
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Device that bound to XDP socket will not have zero refcount until the
userspace application will not close it. This leads to hang inside
'netdev_wait_allrefs()' if device unregistering requested:

  # ip link del p1
  < hang on recvmsg on netlink socket >

  # ps -x | grep ip
  5126  pts/0    D+   0:00 ip link del p1

  # journalctl -b

  Jun 05 07:19:16 kernel:
  unregister_netdevice: waiting for p1 to become free. Usage count = 1

  Jun 05 07:19:27 kernel:
  unregister_netdevice: waiting for p1 to become free. Usage count = 1
  ...

Fix that by implementing NETDEV_UNREGISTER event notification handler
to properly clean up all the resources and unref device.

This should also allow socket killing via ss(8) utility.

Fixes: 965a9909 ("xsk: add support for bind for Rx")
Signed-off-by: Ilya Maximets <i.maximets@samsung.com>
Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Device pointer stored in umem regardless of zero-copy mode,
so we heed to hold the device in all cases.

Fixes: c9b47cc1 ("xsk: fix bug when trying to use both copy and zero-copy on one queue id")
Signed-off-by: Ilya Maximets <i.maximets@samsung.com>
Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Selftests are reporting this failure in test_lwt_seg6local.sh:

+ ip netns exec ns2 ip -6 route add fb00::6 encap bpf in obj test_lwt_seg6local.o sec encap_srh dev veth2
Error fetching program/map!
Failed to parse eBPF program: Operation not permitted

The problem is __attribute__((always_inline)) alone is not enough to prevent
clang from inserting those functions in .text. In that case, .text is not
marked as relocateable.

See the output of objdump -h test_lwt_seg6local.o:

Idx Name          Size      VMA               LMA               File off  Algn
  0 .text         00003530  0000000000000000  0000000000000000  00000040  2**3
                  CONTENTS, ALLOC, LOAD, READONLY, CODE

This causes the iproute bpf loader to fail in bpf_fetch_prog_sec:
bpf_has_call_data returns true but bpf_fetch_prog_relo fails as there's no
relocateable .text section in the file.

To fix this, convert to 'static __always_inline'.

v2: Use 'static __always_inline' instead of 'static inline
    __attribute__((always_inline))'

Fixes: c99a84ea ("selftests/bpf: test for seg6local End.BPF action")
Signed-off-by: Jiri Benc <jbenc@redhat.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

There are currently no tests for ALU64 shift operations when the shift
amount is 0. This adds 6 new tests to make sure they are equivalent
to a no-op. The x32 JIT had such bugs that could have been caught by
these tests.

Cc: Xi Wang <xi.wang@gmail.com>
Signed-off-by: Luke Nelson <luke.r.nels@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

The current x32 BPF JIT does not correctly compile shift operations when
the immediate shift amount is 0. The expected behavior is for this to
be a no-op.

The following program demonstrates the bug. The expexceted result is 1,
but the current JITed code returns 2.

  r0 = 1
  r1 = 1
  r1 <<= 0
  if r1 == 1 goto end
  r0 = 2
end:
  exit

This patch simplifies the code and fixes the bug.

Fixes: 03f5781b ("bpf, x86_32: add eBPF JIT compiler for ia32")
Co-developed-by: Xi Wang <xi.wang@gmail.com>
Signed-off-by: Xi Wang <xi.wang@gmail.com>
Signed-off-by: Luke Nelson <luke.r.nels@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

The current x32 BPF JIT for shift operations is not correct when the
shift amount in a register is 0. The expected behavior is a no-op, whereas
the current implementation changes bits in the destination register.

The following example demonstrates the bug. The expected result of this
program is 1, but the current JITed code returns 2.

  r0 = 1
  r1 = 1
  r2 = 0
  r1 <<= r2
  if r1 == 1 goto end
  r0 = 2
end:
  exit

The bug is caused by an incorrect assumption by the JIT that a shift by
32 clear the register. On x32 however, shifts use the lower 5 bits of
the source, making a shift by 32 equivalent to a shift by 0.

This patch fixes the bug using double-precision shifts, which also
simplifies the code.

Fixes: 03f5781b ("bpf, x86_32: add eBPF JIT compiler for ia32")
Co-developed-by: Xi Wang <xi.wang@gmail.com>
Signed-off-by: Xi Wang <xi.wang@gmail.com>
Signed-off-by: Luke Nelson <luke.r.nels@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

The following commands produce a backtrace and return an error but the xfrm
interface is created (in the wrong netns):
$ ip netns add foo
$ ip netns add bar
$ ip -n foo netns set bar 0
$ ip -n foo link add xfrmi0 link-netnsid 0 type xfrm dev lo if_id 23
RTNETLINK answers: Invalid argument
$ ip -n bar link ls xfrmi0
2: xfrmi0@lo: <NOARP,M-DOWN> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000
    link/none 00:00:00:00:00:00 brd 00:00:00:00:00:00

Here is the backtrace:
[   79.879174] WARNING: CPU: 0 PID: 1178 at net/core/dev.c:8172 rollback_registered_many+0x86/0x3c1
[   79.880260] Modules linked in: xfrm_interface nfsv3 nfs_acl auth_rpcgss nfsv4 nfs lockd grace sunrpc fscache button parport_pc parport serio_raw evdev pcspkr loop ext4 crc16 mbcache jbd2 crc32c_generic ide_cd_mod ide_gd_mod cdrom ata_$
eneric ata_piix libata scsi_mod 8139too piix psmouse i2c_piix4 ide_core 8139cp mii i2c_core floppy
[   79.883698] CPU: 0 PID: 1178 Comm: ip Not tainted 5.2.0-rc6+ #106
[   79.884462] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
[   79.885447] RIP: 0010:rollback_registered_many+0x86/0x3c1
[   79.886120] Code: 01 e8 d7 7d c6 ff 0f 0b 48 8b 45 00 4c 8b 20 48 8d 58 90 49 83 ec 70 48 8d 7b 70 48 39 ef 74 44 8a 83 d0 04 00 00 84 c0 75 1f <0f> 0b e8 61 cd ff ff 48 b8 00 01 00 00 00 00 ad de 48 89 43 70 66
[   79.888667] RSP: 0018:ffffc900015ab740 EFLAGS: 00010246
[   79.889339] RAX: ffff8882353e5700 RBX: ffff8882353e56a0 RCX: ffff8882353e5710
[   79.890174] RDX: ffffc900015ab7e0 RSI: ffffc900015ab7e0 RDI: ffff8882353e5710
[   79.891029] RBP: ffffc900015ab7e0 R08: ffffc900015ab7e0 R09: ffffc900015ab7e0
[   79.891866] R10: ffffc900015ab7a0 R11: ffffffff82233fec R12: ffffc900015ab770
[   79.892728] R13: ffffffff81eb7ec0 R14: ffff88822ed6cf00 R15: 00000000ffffffea
[   79.893557] FS:  00007ff350f31740(0000) GS:ffff888237a00000(0000) knlGS:0000000000000000
[   79.894581] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   79.895317] CR2: 00000000006c8580 CR3: 000000022c272000 CR4: 00000000000006f0
[   79.896137] Call Trace:
[   79.896464]  unregister_netdevice_many+0x12/0x6c
[   79.896998]  __rtnl_newlink+0x6e2/0x73b
[   79.897446]  ? __kmalloc_node_track_caller+0x15e/0x185
[   79.898039]  ? pskb_expand_head+0x5f/0x1fe
[   79.898556]  ? stack_access_ok+0xd/0x2c
[   79.899009]  ? deref_stack_reg+0x12/0x20
[   79.899462]  ? stack_access_ok+0xd/0x2c
[   79.899927]  ? stack_access_ok+0xd/0x2c
[   79.900404]  ? __module_text_address+0x9/0x4f
[   79.900910]  ? is_bpf_text_address+0x5/0xc
[   79.901390]  ? kernel_text_address+0x67/0x7b
[   79.901884]  ? __kernel_text_address+0x1a/0x25
[   79.902397]  ? unwind_get_return_address+0x12/0x23
[   79.903122]  ? __cmpxchg_double_slab.isra.37+0x46/0x77
[   79.903772]  rtnl_newlink+0x43/0x56
[   79.904217]  rtnetlink_rcv_msg+0x200/0x24c

In fact, each time a xfrm interface was created, a netdev was allocated
by __rtnl_newlink()/rtnl_create_link() and then another one by
xfrmi_newlink()/xfrmi_create(). Only the second one was registered, it's
why the previous commands produce a backtrace: dev_change_net_namespace()
was called on a netdev with reg_state set to NETREG_UNINITIALIZED (the
first one).

CC: Lorenzo Colitti <lorenzo@google.com>
CC: Benedict Wong <benedictwong@google.com>
CC: Steffen Klassert <steffen.klassert@secunet.com>
CC: Shannon Nelson <shannon.nelson@oracle.com>
CC: Antony Antony <antony@phenome.org>
CC: Eyal Birger <eyal.birger@gmail.com>
Fixes: f203b76d ("xfrm: Add virtual xfrm interfaces")
Reported-by: Julien Floret <julien.floret@6wind.com>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

syzbot reported following spat:

BUG: KASAN: use-after-free in __write_once_size include/linux/compiler.h:221
BUG: KASAN: use-after-free in hlist_del_rcu include/linux/rculist.h:455
BUG: KASAN: use-after-free in xfrm_hash_rebuild+0xa0d/0x1000 net/xfrm/xfrm_policy.c:1318
Write of size 8 at addr ffff888095e79c00 by task kworker/1:3/8066
Workqueue: events xfrm_hash_rebuild
Call Trace:
 __write_once_size include/linux/compiler.h:221 [inline]
 hlist_del_rcu include/linux/rculist.h:455 [inline]
 xfrm_hash_rebuild+0xa0d/0x1000 net/xfrm/xfrm_policy.c:1318
 process_one_work+0x814/0x1130 kernel/workqueue.c:2269
Allocated by task 8064:
 __kmalloc+0x23c/0x310 mm/slab.c:3669
 kzalloc include/linux/slab.h:742 [inline]
 xfrm_hash_alloc+0x38/0xe0 net/xfrm/xfrm_hash.c:21
 xfrm_policy_init net/xfrm/xfrm_policy.c:4036 [inline]
 xfrm_net_init+0x269/0xd60 net/xfrm/xfrm_policy.c:4120
 ops_init+0x336/0x420 net/core/net_namespace.c:130
 setup_net+0x212/0x690 net/core/net_namespace.c:316

The faulting address is the address of the old chain head,
free'd by xfrm_hash_resize().

In xfrm_hash_rehash(), chain heads get re-initialized without
any hlist_del_rcu:

 for (i = hmask; i >= 0; i--)
    INIT_HLIST_HEAD(odst + i);

Then, hlist_del_rcu() gets called on the about to-be-reinserted policy
when iterating the per-net list of policies.

hlist_del_rcu() will then make chain->first be nonzero again:

static inline void __hlist_del(struct hlist_node *n)
{
   struct hlist_node *next = n->next;   // address of next element in list
   struct hlist_node **pprev = n->pprev;// location of previous elem, this
                                        // can point at chain->first
        WRITE_ONCE(*pprev, next);       // chain->first points to next elem
        if (next)
                next->pprev = pprev;

Then, when we walk chainlist to find insertion point, we may find a
non-empty list even though we're supposedly reinserting the first
policy to an empty chain.

To fix this first unlink all exact and inexact policies instead of
zeroing the list heads.

Add the commands equivalent to the syzbot reproducer to xfrm_policy.sh,
without fix KASAN catches the corruption as it happens, SLUB poisoning
detects it a bit later.

Reported-by: syzbot+0165480d4ef07360eeda@syzkaller.appspotmail.com
Fixes: 1548bc4e ("xfrm: policy: delete inexact policies from inexact list on hash rebuild")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

The psock_tpacket test will need to access /proc/kallsyms, this would
require the kernel config CONFIG_KALLSYMS to be enabled first.

Apart from adding CONFIG_KALLSYMS to the net/config file here, check the
file existence to determine if we can run this test will be helpful to
avoid a false-positive test result when testing it directly with the
following commad against a kernel that have CONFIG_KALLSYMS disabled:
    make -C tools/testing/selftests TARGETS=net run_tests
Signed-off-by: Po-Hsu Lin <po-hsu.lin@canonical.com>
Acked-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

If the rxrpc_eproto tracepoint is enabled, an oops will be cause by the
trace line that rxrpc_extract_header() tries to emit when a protocol error
occurs (typically because the packet is short) because the call argument is
NULL.

Fix this by using ?: to assume 0 as the debug_id if call is NULL.

This can then be induced by:

	echo -e '\0\0\0\0\0\0\0\0' | ncat -4u --send-only <addr> 20001

where addr has the following program running on it:

	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	#include <unistd.h>
	#include <sys/socket.h>
	#include <arpa/inet.h>
	#include <linux/rxrpc.h>
	int main(void)
	{
		struct sockaddr_rxrpc srx;
		int fd;
		memset(&srx, 0, sizeof(srx));
		srx.srx_family			= AF_RXRPC;
		srx.srx_service			= 0;
		srx.transport_type		= AF_INET;
		srx.transport_len		= sizeof(srx.transport.sin);
		srx.transport.sin.sin_family	= AF_INET;
		srx.transport.sin.sin_port	= htons(0x4e21);
		fd = socket(AF_RXRPC, SOCK_DGRAM, AF_INET6);
		bind(fd, (struct sockaddr *)&srx, sizeof(srx));
		sleep(20);
		return 0;
	}

It results in the following oops.

	BUG: kernel NULL pointer dereference, address: 0000000000000340
	#PF: supervisor read access in kernel mode
	#PF: error_code(0x0000) - not-present page
	...
	RIP: 0010:trace_event_raw_event_rxrpc_rx_eproto+0x47/0xac
	...
	Call Trace:
	 <IRQ>
	 rxrpc_extract_header+0x86/0x171
	 ? rcu_read_lock_sched_held+0x5d/0x63
	 ? rxrpc_new_skb+0xd4/0x109
	 rxrpc_input_packet+0xef/0x14fc
	 ? rxrpc_input_data+0x986/0x986
	 udp_queue_rcv_one_skb+0xbf/0x3d0
	 udp_unicast_rcv_skb.isra.8+0x64/0x71
	 ip_protocol_deliver_rcu+0xe4/0x1b4
	 ip_local_deliver+0xf0/0x154
	 __netif_receive_skb_one_core+0x50/0x6c
	 netif_receive_skb_internal+0x26b/0x2e9
	 napi_gro_receive+0xf8/0x1da
	 rtl8169_poll+0x303/0x4c4
	 net_rx_action+0x10e/0x333
	 __do_softirq+0x1a5/0x38f
	 irq_exit+0x54/0xc4
	 do_IRQ+0xda/0xf8
	 common_interrupt+0xf/0xf
	 </IRQ>
	 ...
	 ? cpuidle_enter_state+0x23c/0x34d
	 cpuidle_enter+0x2a/0x36
	 do_idle+0x163/0x1ea
	 cpu_startup_entry+0x1d/0x1f
	 start_secondary+0x157/0x172
	 secondary_startup_64+0xa4/0xb0

Fixes: a25e21f0 ("rxrpc, afs: Use debug_ids rather than pointers in traces")
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This is for fixing bug KMSAN: uninit-value in ax88772_bind

Tested by
https://groups.google.com/d/msg/syzkaller-bugs/aFQurGotng4/eB_HlNhhCwAJ

Reported-by: syzbot+8a3fc6674bbc3978ed4e@syzkaller.appspotmail.com

syzbot found the following crash on:

HEAD commit:    f75e4cfe kmsan: use kmsan_handle_urb() in urb.c
git tree:       kmsan
console output: https://syzkaller.appspot.com/x/log.txt?x=136d720ea00000
kernel config:
https://syzkaller.appspot.com/x/.config?x=602468164ccdc30a
dashboard link:
https://syzkaller.appspot.com/bug?extid=8a3fc6674bbc3978ed4e
compiler:       clang version 9.0.0 (/home/glider/llvm/clang
06d00afa61eef8f7f501ebdb4e8612ea43ec2d78)
syz repro:
https://syzkaller.appspot.com/x/repro.syz?x=12788316a00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=120359aaa00000

==================================================================
BUG: KMSAN: uninit-value in is_valid_ether_addr
include/linux/etherdevice.h:200 [inline]
BUG: KMSAN: uninit-value in asix_set_netdev_dev_addr
drivers/net/usb/asix_devices.c:73 [inline]
BUG: KMSAN: uninit-value in ax88772_bind+0x93d/0x11e0
drivers/net/usb/asix_devices.c:724
CPU: 0 PID: 3348 Comm: kworker/0:2 Not tainted 5.1.0+ #1
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Workqueue: usb_hub_wq hub_event
Call Trace:
  __dump_stack lib/dump_stack.c:77 [inline]
  dump_stack+0x191/0x1f0 lib/dump_stack.c:113
  kmsan_report+0x130/0x2a0 mm/kmsan/kmsan.c:622
  __msan_warning+0x75/0xe0 mm/kmsan/kmsan_instr.c:310
  is_valid_ether_addr include/linux/etherdevice.h:200 [inline]
  asix_set_netdev_dev_addr drivers/net/usb/asix_devices.c:73 [inline]
  ax88772_bind+0x93d/0x11e0 drivers/net/usb/asix_devices.c:724
  usbnet_probe+0x10f5/0x3940 drivers/net/usb/usbnet.c:1728
  usb_probe_interface+0xd66/0x1320 drivers/usb/core/driver.c:361
  really_probe+0xdae/0x1d80 drivers/base/dd.c:513
  driver_probe_device+0x1b3/0x4f0 drivers/base/dd.c:671
  __device_attach_driver+0x5b8/0x790 drivers/base/dd.c:778
  bus_for_each_drv+0x28e/0x3b0 drivers/base/bus.c:454
  __device_attach+0x454/0x730 drivers/base/dd.c:844
  device_initial_probe+0x4a/0x60 drivers/base/dd.c:891
  bus_probe_device+0x137/0x390 drivers/base/bus.c:514
  device_add+0x288d/0x30e0 drivers/base/core.c:2106
  usb_set_configuration+0x30dc/0x3750 drivers/usb/core/message.c:2027
  generic_probe+0xe7/0x280 drivers/usb/core/generic.c:210
  usb_probe_device+0x14c/0x200 drivers/usb/core/driver.c:266
  really_probe+0xdae/0x1d80 drivers/base/dd.c:513
  driver_probe_device+0x1b3/0x4f0 drivers/base/dd.c:671
  __device_attach_driver+0x5b8/0x790 drivers/base/dd.c:778
  bus_for_each_drv+0x28e/0x3b0 drivers/base/bus.c:454
  __device_attach+0x454/0x730 drivers/base/dd.c:844
  device_initial_probe+0x4a/0x60 drivers/base/dd.c:891
  bus_probe_device+0x137/0x390 drivers/base/bus.c:514
  device_add+0x288d/0x30e0 drivers/base/core.c:2106
  usb_new_device+0x23e5/0x2ff0 drivers/usb/core/hub.c:2534
  hub_port_connect drivers/usb/core/hub.c:5089 [inline]
  hub_port_connect_change drivers/usb/core/hub.c:5204 [inline]
  port_event drivers/usb/core/hub.c:5350 [inline]
  hub_event+0x48d1/0x7290 drivers/usb/core/hub.c:5432
  process_one_work+0x1572/0x1f00 kernel/workqueue.c:2269
  process_scheduled_works kernel/workqueue.c:2331 [inline]
  worker_thread+0x189c/0x2460 kernel/workqueue.c:2417
  kthread+0x4b5/0x4f0 kernel/kthread.c:254
  ret_from_fork+0x35/0x40 arch/x86/entry/entry_64.S:355
Signed-off-by: Phong Tran <tranmanphong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Andreas Steinmetz says:

====================
macsec: fix some bugs in the receive path

This series fixes some bugs in the receive path of macsec. The first
is a use after free when processing macsec frames with a SecTAG that
has the TCI E bit set but the C bit clear. In the 2nd bug, the driver
leaves an invalid checksumming state after decrypting the packet.

This is a combined effort of Sabrina Dubroca <sd@queasysnail.net> and me.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Fix checksumming after decryption.
Signed-off-by: Andreas Steinmetz <ast@domdv.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

Fix use-after-free of skb when rx_handler returns RX_HANDLER_PASS.
Signed-off-by: Andreas Steinmetz <ast@domdv.de>
Acked-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

If sendmsg() or sendmmsg() is called on a connected socket that hasn't had
bind() called on it, then an oops will occur when the kernel tries to
connect the call because no local endpoint has been allocated.

Fix this by implicitly binding the socket if it is in the
RXRPC_CLIENT_UNBOUND state, just like it does for the RXRPC_UNBOUND state.

Further, the state should be transitioned to RXRPC_CLIENT_BOUND after this
to prevent further attempts to bind it.

This can be tested with:

	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	#include <sys/socket.h>
	#include <arpa/inet.h>
	#include <linux/rxrpc.h>
	static const unsigned char inet6_addr[16] = {
		0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, -1, 0xac, 0x14, 0x14, 0xaa
	};
	int main(void)
	{
		struct sockaddr_rxrpc srx;
		struct cmsghdr *cm;
		struct msghdr msg;
		unsigned char control[16];
		int fd;
		memset(&srx, 0, sizeof(srx));
		srx.srx_family = 0x21;
		srx.srx_service = 0;
		srx.transport_type = AF_INET;
		srx.transport_len = 0x1c;
		srx.transport.sin6.sin6_family = AF_INET6;
		srx.transport.sin6.sin6_port = htons(0x4e22);
		srx.transport.sin6.sin6_flowinfo = htons(0x4e22);
		srx.transport.sin6.sin6_scope_id = htons(0xaa3b);
		memcpy(&srx.transport.sin6.sin6_addr, inet6_addr, 16);
		cm = (struct cmsghdr *)control;
		cm->cmsg_len	= CMSG_LEN(sizeof(unsigned long));
		cm->cmsg_level	= SOL_RXRPC;
		cm->cmsg_type	= RXRPC_USER_CALL_ID;
		*(unsigned long *)CMSG_DATA(cm) = 0;
		msg.msg_name = NULL;
		msg.msg_namelen = 0;
		msg.msg_iov = NULL;
		msg.msg_iovlen = 0;
		msg.msg_control = control;
		msg.msg_controllen = cm->cmsg_len;
		msg.msg_flags = 0;
		fd = socket(AF_RXRPC, SOCK_DGRAM, AF_INET);
		connect(fd, (struct sockaddr *)&srx, sizeof(srx));
		sendmsg(fd, &msg, 0);
		return 0;
	}

Leading to the following oops:

	BUG: kernel NULL pointer dereference, address: 0000000000000018
	#PF: supervisor read access in kernel mode
	#PF: error_code(0x0000) - not-present page
	...
	RIP: 0010:rxrpc_connect_call+0x42/0xa01
	...
	Call Trace:
	 ? mark_held_locks+0x47/0x59
	 ? __local_bh_enable_ip+0xb6/0xba
	 rxrpc_new_client_call+0x3b1/0x762
	 ? rxrpc_do_sendmsg+0x3c0/0x92e
	 rxrpc_do_sendmsg+0x3c0/0x92e
	 rxrpc_sendmsg+0x16b/0x1b5
	 sock_sendmsg+0x2d/0x39
	 ___sys_sendmsg+0x1a4/0x22a
	 ? release_sock+0x19/0x9e
	 ? reacquire_held_locks+0x136/0x160
	 ? release_sock+0x19/0x9e
	 ? find_held_lock+0x2b/0x6e
	 ? __lock_acquire+0x268/0xf73
	 ? rxrpc_connect+0xdd/0xe4
	 ? __local_bh_enable_ip+0xb6/0xba
	 __sys_sendmsg+0x5e/0x94
	 do_syscall_64+0x7d/0x1bf
	 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Fixes: 2341e077 ("rxrpc: Simplify connect() implementation and simplify sendmsg() op")
Reported-by: syzbot+7966f2a0b2c7da8939b4@syzkaller.appspotmail.com
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Nikolay Aleksandrov says:

====================
net: bridge: fix possible stale skb pointers

In the bridge driver we have a couple of places which call pskb_may_pull
but we've cached skb pointers before that and use them after which can
lead to out-of-bounds/stale pointer use. I've had these in my "to fix"
list for some time and now we got a report (patch 01) so here they are.
Patches 02-04 are fixes based on code inspection. Also patch 01 was
tested by Martin Weinelt, Martin if you don't mind please add your
tested-by tag to it by replying with Tested-by: name <email>.
I've also briefly tested the set by trying to exercise those code paths.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Don't cache eth dest pointer before calling pskb_may_pull.

Fixes: cf0f02d0 ("[BRIDGE]: use llc for receiving STP packets")
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

We would cache ether dst pointer on input in br_handle_frame_finish but
after the neigh suppress code that could lead to a stale pointer since
both ipv4 and ipv6 suppress code do pskb_may_pull. This means we have to
always reload it after the suppress code so there's no point in having
it cached just retrieve it directly.

Fixes: 057658cb ("bridge: suppress arp pkts on BR_NEIGH_SUPPRESS ports")
Fixes: ed842fae ("bridge: suppress nd pkts on BR_NEIGH_SUPPRESS ports")
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

We get a pointer to the ipv6 hdr in br_ip6_multicast_query but we may
call pskb_may_pull afterwards and end up using a stale pointer.
So use the header directly, it's just 1 place where it's needed.

Fixes: 08b202b6 ("bridge br_multicast: IPv6 MLD support.")
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Tested-by: Martin Weinelt <martin@linuxlounge.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

We take a pointer to grec prior to calling pskb_may_pull and use it
afterwards to get nsrcs so record nsrcs before the pull when handling
igmp3 and we get a pointer to nsrcs and call pskb_may_pull when handling
mld2 which again could lead to reading 2 bytes out-of-bounds.

 ==================================================================
 BUG: KASAN: use-after-free in br_multicast_rcv+0x480c/0x4ad0 [bridge]
 Read of size 2 at addr ffff8880421302b4 by task ksoftirqd/1/16

 CPU: 1 PID: 16 Comm: ksoftirqd/1 Tainted: G           OE     5.2.0-rc6+ #1
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
 Call Trace:
  dump_stack+0x71/0xab
  print_address_description+0x6a/0x280
  ? br_multicast_rcv+0x480c/0x4ad0 [bridge]
  __kasan_report+0x152/0x1aa
  ? br_multicast_rcv+0x480c/0x4ad0 [bridge]
  ? br_multicast_rcv+0x480c/0x4ad0 [bridge]
  kasan_report+0xe/0x20
  br_multicast_rcv+0x480c/0x4ad0 [bridge]
  ? br_multicast_disable_port+0x150/0x150 [bridge]
  ? ktime_get_with_offset+0xb4/0x150
  ? __kasan_kmalloc.constprop.6+0xa6/0xf0
  ? __netif_receive_skb+0x1b0/0x1b0
  ? br_fdb_update+0x10e/0x6e0 [bridge]
  ? br_handle_frame_finish+0x3c6/0x11d0 [bridge]
  br_handle_frame_finish+0x3c6/0x11d0 [bridge]
  ? br_pass_frame_up+0x3a0/0x3a0 [bridge]
  ? virtnet_probe+0x1c80/0x1c80 [virtio_net]
  br_handle_frame+0x731/0xd90 [bridge]
  ? select_idle_sibling+0x25/0x7d0
  ? br_handle_frame_finish+0x11d0/0x11d0 [bridge]
  __netif_receive_skb_core+0xced/0x2d70
  ? virtqueue_get_buf_ctx+0x230/0x1130 [virtio_ring]
  ? do_xdp_generic+0x20/0x20
  ? virtqueue_napi_complete+0x39/0x70 [virtio_net]
  ? virtnet_poll+0x94d/0xc78 [virtio_net]
  ? receive_buf+0x5120/0x5120 [virtio_net]
  ? __netif_receive_skb_one_core+0x97/0x1d0
  __netif_receive_skb_one_core+0x97/0x1d0
  ? __netif_receive_skb_core+0x2d70/0x2d70
  ? _raw_write_trylock+0x100/0x100
  ? __queue_work+0x41e/0xbe0
  process_backlog+0x19c/0x650
  ? _raw_read_lock_irq+0x40/0x40
  net_rx_action+0x71e/0xbc0
  ? __switch_to_asm+0x40/0x70
  ? napi_complete_done+0x360/0x360
  ? __switch_to_asm+0x34/0x70
  ? __switch_to_asm+0x40/0x70
  ? __schedule+0x85e/0x14d0
  __do_softirq+0x1db/0x5f9
  ? takeover_tasklets+0x5f0/0x5f0
  run_ksoftirqd+0x26/0x40
  smpboot_thread_fn+0x443/0x680
  ? sort_range+0x20/0x20
  ? schedule+0x94/0x210
  ? __kthread_parkme+0x78/0xf0
  ? sort_range+0x20/0x20
  kthread+0x2ae/0x3a0
  ? kthread_create_worker_on_cpu+0xc0/0xc0
  ret_from_fork+0x35/0x40

 The buggy address belongs to the page:
 page:ffffea0001084c00 refcount:0 mapcount:-128 mapping:0000000000000000 index:0x0
 flags: 0xffffc000000000()
 raw: 00ffffc000000000 ffffea0000cfca08 ffffea0001098608 0000000000000000
 raw: 0000000000000000 0000000000000003 00000000ffffff7f 0000000000000000
 page dumped because: kasan: bad access detected

 Memory state around the buggy address:
 ffff888042130180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888042130200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 > ffff888042130280: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                     ^
 ffff888042130300: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888042130380: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ==================================================================
 Disabling lock debugging due to kernel taint

Fixes: bc8c20ac ("bridge: multicast: treat igmpv3 report with INCLUDE and no sources as a leave")
Reported-by: Martin Weinelt <martin@linuxlounge.net>
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Tested-by: Martin Weinelt <martin@linuxlounge.net>
Signed-off-by: David S. Miller <davem@davemloft.net>