linux-stable.git/include/net, branch v5.16.9

net, neigh: Do not trigger immediate probes on NUD_FAILED from neigh_managed_work

2022-02-08T17:35:15+00:00

commit 4a81f6da9cb2d1ef911131a6fd8bd15cb61fc772 upstream.

syzkaller was able to trigger a deadlock for NTF_MANAGED entries [0]:

  kworker/0:16/14617 is trying to acquire lock:
  ffffffff8d4dd370 (&tbl->lock){++-.}-{2:2}, at: ___neigh_create+0x9e1/0x2990 net/core/neighbour.c:652
  [...]
  but task is already holding lock:
  ffffffff8d4dd370 (&tbl->lock){++-.}-{2:2}, at: neigh_managed_work+0x35/0x250 net/core/neighbour.c:1572

The neighbor entry turned to NUD_FAILED state, where __neigh_event_send()
triggered an immediate probe as per commit cd28ca0a3dd1 ("neigh: reduce
arp latency") via neigh_probe() given table lock was held.

One option to fix this situation is to defer the neigh_probe() back to
the neigh_timer_handler() similarly as pre cd28ca0a3dd1. For the case
of NTF_MANAGED, this deferral is acceptable given this only happens on
actual failure state and regular / expected state is NUD_VALID with the
entry already present.

The fix adds a parameter to __neigh_event_send() in order to communicate
whether immediate probe is allowed or disallowed. Existing call-sites
of neigh_event_send() default as-is to immediate probe. However, the
neigh_managed_work() disables it via use of neigh_event_send_probe().

[0] 
  __dump_stack lib/dump_stack.c:88 [inline]
  dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
  print_deadlock_bug kernel/locking/lockdep.c:2956 [inline]
  check_deadlock kernel/locking/lockdep.c:2999 [inline]
  validate_chain kernel/locking/lockdep.c:3788 [inline]
  __lock_acquire.cold+0x149/0x3ab kernel/locking/lockdep.c:5027
  lock_acquire kernel/locking/lockdep.c:5639 [inline]
  lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5604
  __raw_write_lock_bh include/linux/rwlock_api_smp.h:202 [inline]
  _raw_write_lock_bh+0x2f/0x40 kernel/locking/spinlock.c:334
  ___neigh_create+0x9e1/0x2990 net/core/neighbour.c:652
  ip6_finish_output2+0x1070/0x14f0 net/ipv6/ip6_output.c:123
  __ip6_finish_output net/ipv6/ip6_output.c:191 [inline]
  __ip6_finish_output+0x61e/0xe90 net/ipv6/ip6_output.c:170
  ip6_finish_output+0x32/0x200 net/ipv6/ip6_output.c:201
  NF_HOOK_COND include/linux/netfilter.h:296 [inline]
  ip6_output+0x1e4/0x530 net/ipv6/ip6_output.c:224
  dst_output include/net/dst.h:451 [inline]
  NF_HOOK include/linux/netfilter.h:307 [inline]
  ndisc_send_skb+0xa99/0x17f0 net/ipv6/ndisc.c:508
  ndisc_send_ns+0x3a9/0x840 net/ipv6/ndisc.c:650
  ndisc_solicit+0x2cd/0x4f0 net/ipv6/ndisc.c:742
  neigh_probe+0xc2/0x110 net/core/neighbour.c:1040
  __neigh_event_send+0x37d/0x1570 net/core/neighbour.c:1201
  neigh_event_send include/net/neighbour.h:470 [inline]
  neigh_managed_work+0x162/0x250 net/core/neighbour.c:1574
  process_one_work+0x9ac/0x1650 kernel/workqueue.c:2307
  worker_thread+0x657/0x1110 kernel/workqueue.c:2454
  kthread+0x2e9/0x3a0 kernel/kthread.c:377
  ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
  

Fixes: 7482e3841d52 ("net, neigh: Add NTF_MANAGED flag for managed neighbor entries")
Reported-by: syzbot+5239d0e1778a500d477a@syzkaller.appspotmail.com
Signed-off-by: Daniel Borkmann 
Cc: Eric Dumazet 
Cc: Roopa Prabhu 
Tested-by: syzbot+5239d0e1778a500d477a@syzkaller.appspotmail.com
Reviewed-by: David Ahern 
Link: https://lore.kernel.org/r/20220201193942.5055-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman

ipv4: remove sparse error in ip_neigh_gw4()

2022-02-01T16:29:18+00:00

[ Upstream commit 3c42b2019863b327caa233072c50739d4144dd16 ]

./include/net/route.h:373:48: warning: incorrect type in argument 2 (different base types)
./include/net/route.h:373:48:    expected unsigned int [usertype] key
./include/net/route.h:373:48:    got restricted __be32 [usertype] daddr

Fixes: 5c9f7c1dfc2e ("ipv4: Add helpers for neigh lookup for nexthop")
Signed-off-by: Eric Dumazet 
Reviewed-by: David Ahern 
Link: https://lore.kernel.org/r/20220127013404.1279313-1-eric.dumazet@gmail.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

Revert "ipv6: Honor all IPv6 PIO Valid Lifetime values"

2022-02-01T16:29:18+00:00

[ Upstream commit 36268983e90316b37000a005642af42234dabb36 ]

This reverts commit b75326c201242de9495ff98e5d5cff41d7fc0d9d.

This commit breaks Linux compatibility with USGv6 tests. The RFC this
commit was based on is actually an expired draft: no published RFC
currently allows the new behaviour it introduced.

Without full IETF endorsement, the flash renumbering scenario this
patch was supposed to enable is never going to work, as other IPv6
equipements on the same LAN will keep the 2 hours limit.

Fixes: b75326c20124 ("ipv6: Honor all IPv6 PIO Valid Lifetime values")
Signed-off-by: Guillaume Nault 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

ipv6: annotate accesses to fn->fn_sernum

2022-02-01T16:29:12+00:00

commit aafc2e3285c2d7a79b7ee15221c19fbeca7b1509 upstream.

struct fib6_node's fn_sernum field can be
read while other threads change it.

Add READ_ONCE()/WRITE_ONCE() annotations.

Do not change existing smp barriers in fib6_get_cookie_safe()
and __fib6_update_sernum_upto_root()

syzbot reported:

BUG: KCSAN: data-race in fib6_clean_node / inet6_csk_route_socket

write to 0xffff88813df62e2c of 4 bytes by task 1920 on cpu 1:
 fib6_clean_node+0xc2/0x260 net/ipv6/ip6_fib.c:2178
 fib6_walk_continue+0x38e/0x430 net/ipv6/ip6_fib.c:2112
 fib6_walk net/ipv6/ip6_fib.c:2160 [inline]
 fib6_clean_tree net/ipv6/ip6_fib.c:2240 [inline]
 __fib6_clean_all+0x1a9/0x2e0 net/ipv6/ip6_fib.c:2256
 fib6_flush_trees+0x6c/0x80 net/ipv6/ip6_fib.c:2281
 rt_genid_bump_ipv6 include/net/net_namespace.h:488 [inline]
 addrconf_dad_completed+0x57f/0x870 net/ipv6/addrconf.c:4230
 addrconf_dad_work+0x908/0x1170
 process_one_work+0x3f6/0x960 kernel/workqueue.c:2307
 worker_thread+0x616/0xa70 kernel/workqueue.c:2454
 kthread+0x1bf/0x1e0 kernel/kthread.c:359
 ret_from_fork+0x1f/0x30

read to 0xffff88813df62e2c of 4 bytes by task 15701 on cpu 0:
 fib6_get_cookie_safe include/net/ip6_fib.h:285 [inline]
 rt6_get_cookie include/net/ip6_fib.h:306 [inline]
 ip6_dst_store include/net/ip6_route.h:234 [inline]
 inet6_csk_route_socket+0x352/0x3c0 net/ipv6/inet6_connection_sock.c:109
 inet6_csk_xmit+0x91/0x1e0 net/ipv6/inet6_connection_sock.c:121
 __tcp_transmit_skb+0x1323/0x1840 net/ipv4/tcp_output.c:1402
 tcp_transmit_skb net/ipv4/tcp_output.c:1420 [inline]
 tcp_write_xmit+0x1450/0x4460 net/ipv4/tcp_output.c:2680
 __tcp_push_pending_frames+0x68/0x1c0 net/ipv4/tcp_output.c:2864
 tcp_push+0x2d9/0x2f0 net/ipv4/tcp.c:725
 mptcp_push_release net/mptcp/protocol.c:1491 [inline]
 __mptcp_push_pending+0x46c/0x490 net/mptcp/protocol.c:1578
 mptcp_sendmsg+0x9ec/0xa50 net/mptcp/protocol.c:1764
 inet6_sendmsg+0x5f/0x80 net/ipv6/af_inet6.c:643
 sock_sendmsg_nosec net/socket.c:705 [inline]
 sock_sendmsg net/socket.c:725 [inline]
 kernel_sendmsg+0x97/0xd0 net/socket.c:745
 sock_no_sendpage+0x84/0xb0 net/core/sock.c:3086
 inet_sendpage+0x9d/0xc0 net/ipv4/af_inet.c:834
 kernel_sendpage+0x187/0x200 net/socket.c:3492
 sock_sendpage+0x5a/0x70 net/socket.c:1007
 pipe_to_sendpage+0x128/0x160 fs/splice.c:364
 splice_from_pipe_feed fs/splice.c:418 [inline]
 __splice_from_pipe+0x207/0x500 fs/splice.c:562
 splice_from_pipe fs/splice.c:597 [inline]
 generic_splice_sendpage+0x94/0xd0 fs/splice.c:746
 do_splice_from fs/splice.c:767 [inline]
 direct_splice_actor+0x80/0xa0 fs/splice.c:936
 splice_direct_to_actor+0x345/0x650 fs/splice.c:891
 do_splice_direct+0x106/0x190 fs/splice.c:979
 do_sendfile+0x675/0xc40 fs/read_write.c:1245
 __do_sys_sendfile64 fs/read_write.c:1310 [inline]
 __se_sys_sendfile64 fs/read_write.c:1296 [inline]
 __x64_sys_sendfile64+0x102/0x140 fs/read_write.c:1296
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x0000026f -> 0x00000271

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 15701 Comm: syz-executor.2 Not tainted 5.16.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011

The Fixes tag I chose is probably arbitrary, I do not think
we need to backport this patch to older kernels.

Fixes: c5cff8561d2d ("ipv6: add rcu grace period before freeing fib6_node")
Signed-off-by: Eric Dumazet 
Reported-by: syzbot 
Link: https://lore.kernel.org/r/20220120174112.1126644-1-eric.dumazet@gmail.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman

ipv4: avoid using shared IP generator for connected sockets

2022-02-01T16:29:11+00:00

commit 23f57406b82de51809d5812afd96f210f8b627f3 upstream.

ip_select_ident_segs() has been very conservative about using
the connected socket private generator only for packets with IP_DF
set, claiming it was needed for some VJ compression implementations.

As mentioned in this referenced document, this can be abused.
(Ref: Off-Path TCP Exploits of the Mixed IPID Assignment)

Before switching to pure random IPID generation and possibly hurt
some workloads, lets use the private inet socket generator.

Not only this will remove one vulnerability, this will also
improve performance of TCP flows using pmtudisc==IP_PMTUDISC_DONT

Fixes: 73f156a6e8c1 ("inetpeer: get rid of ip_id_count")
Signed-off-by: Eric Dumazet 
Reviewed-by: David Ahern 
Reported-by: Ray Che 
Cc: Willy Tarreau 
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman

net_sched: restore "mpu xxx" handling

2022-01-27T11:03:01+00:00

commit fb80445c438c78b40b547d12b8d56596ce4ccfeb upstream.

commit 56b765b79e9a ("htb: improved accuracy at high rates") broke
"overhead X", "linklayer atm" and "mpu X" attributes.

"overhead X" and "linklayer atm" have already been fixed. This restores
the "mpu X" handling, as might be used by DOCSIS or Ethernet shaping:

    tc class add ... htb rate X overhead 4 mpu 64

The code being fixed is used by htb, tbf and act_police. Cake has its
own mpu handling. qdisc_calculate_pkt_len still uses the size table
containing values adjusted for mpu by user space.

iproute2 tc has always passed mpu into the kernel via a tc_ratespec
structure, but the kernel never directly acted on it, merely stored it
so that it could be read back by `tc class show`.

Rather, tc would generate length-to-time tables that included the mpu
(and linklayer) in their construction, and the kernel used those tables.

Since v3.7, the tables were no longer used. Along with "mpu", this also
broke "overhead" and "linklayer" which were fixed in 01cb71d2d47b
("net_sched: restore "overhead xxx" handling", v3.10) and 8a8e3d84b171
("net_sched: restore "linklayer atm" handling", v3.11).

"overhead" was fixed by simply restoring use of tc_ratespec::overhead -
this had originally been used by the kernel but was initially omitted
from the new non-table-based calculations.

"linklayer" had been handled in the table like "mpu", but the mode was
not originally passed in tc_ratespec. The new implementation was made to
handle it by getting new versions of tc to pass the mode in an extended
tc_ratespec, and for older versions of tc the table contents were analysed
at load time to deduce linklayer.

As "mpu" has always been given to the kernel in tc_ratespec,
accompanying the mpu-based table, we can restore system functionality
with no userspace change by making the kernel act on the tc_ratespec
value.

Fixes: 56b765b79e9a ("htb: improved accuracy at high rates")
Signed-off-by: Kevin Bracey 
Cc: Eric Dumazet 
Cc: Jiri Pirko 
Cc: Vimalkumar 
Link: https://lore.kernel.org/r/20220112170210.1014351-1-kevin@bracey.fi
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman

inet: frags: annotate races around fqdir->dead and fqdir->high_thresh

2022-01-27T11:02:59+00:00

commit 91341fa0003befd097e190ec2a4bf63ad957c49a upstream.

Both fields can be read/written without synchronization,
add proper accessors and documentation.

Fixes: d5dd88794a13 ("inet: fix various use-after-free in defrags units")
Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

xfrm: fix dflt policy check when there is no policy configured

2022-01-27T11:02:47+00:00

commit ec3bb890817e4398f2d46e12e2e205495b116be9 upstream.

When there is no policy configured on the system, the default policy is
checked in xfrm_route_forward. However, it was done with the wrong
direction (XFRM_POLICY_FWD instead of XFRM_POLICY_OUT).
The default policy for XFRM_POLICY_FWD was checked just before, with a call
to xfrm[46]_policy_check().

CC: stable@vger.kernel.org
Fixes: 2d151d39073a ("xfrm: Add possibility to set the default to block if we have no policy")
Signed-off-by: Nicolas Dichtel 
Signed-off-by: Steffen Klassert 
Signed-off-by: Greg Kroah-Hartman

xfrm: rate limit SA mapping change message to user space

2022-01-27T11:02:28+00:00

[ Upstream commit 4e484b3e969b52effd95c17f7a86f39208b2ccf4 ]

Kernel generates mapping change message, XFRM_MSG_MAPPING,
when a source port chage is detected on a input state with UDP
encapsulation set.  Kernel generates a message for each IPsec packet
with new source port.  For a high speed flow per packet mapping change
message can be excessive, and can overload the user space listener.

Introduce rate limiting for XFRM_MSG_MAPPING message to the user space.

The rate limiting is configurable via netlink, when adding a new SA or
updating it. Use the new attribute XFRMA_MTIMER_THRESH in seconds.

v1->v2 change:
	update xfrm_sa_len()

v2->v3 changes:
	use u32 insted unsigned long to reduce size of struct xfrm_state
	fix xfrm_ompat size Reported-by: kernel test robot 
	accept XFRM_MSG_MAPPING only when XFRMA_ENCAP is present

Co-developed-by: Thomas Egerer 
Signed-off-by: Thomas Egerer 
Signed-off-by: Antony Antony 
Signed-off-by: Steffen Klassert 
Signed-off-by: Sasha Levin

net: openvswitch: Fix ct_state nat flags for conns arriving from tc

2022-01-27T11:02:01+00:00

[ Upstream commit 6f022c2ddbcefaee79502ce5386dfe351d457070 ]

Netfilter conntrack maintains NAT flags per connection indicating
whether NAT was configured for the connection. Openvswitch maintains
NAT flags on the per packet flow key ct_state field, indicating
whether NAT was actually executed on the packet.

When a packet misses from tc to ovs the conntrack NAT flags are set.
However, NAT was not necessarily executed on the packet because the
connection's state might still be in NEW state. As such, openvswitch
wrongly assumes that NAT was executed and sets an incorrect flow key
NAT flags.

Fix this, by flagging to openvswitch which NAT was actually done in
act_ct via tc_skb_ext and tc_skb_cb to the openvswitch module, so
the packet flow key NAT flags will be correctly set.

Fixes: b57dc7c13ea9 ("net/sched: Introduce action ct")
Signed-off-by: Paul Blakey 
Acked-by: Jamal Hadi Salim 
Link: https://lore.kernel.org/r/20220106153804.26451-1-paulb@nvidia.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin