linux/net
Ido Schimmel 3106a08475 nexthop: Fix memory leaks in nexthop notification chain listeners
syzkaller discovered memory leaks [1] that can be reduced to the
following commands:

 # ip nexthop add id 1 blackhole
 # devlink dev reload pci/0000:06:00.0

As part of the reload flow, mlxsw will unregister its netdevs and then
unregister from the nexthop notification chain. Before unregistering
from the notification chain, mlxsw will receive delete notifications for
nexthop objects using netdevs registered by mlxsw or their uppers. mlxsw
will not receive notifications for nexthops using netdevs that are not
dismantled as part of the reload flow. For example, the blackhole
nexthop above that internally uses the loopback netdev as its nexthop
device.

One way to fix this problem is to have listeners flush their nexthop
tables after unregistering from the notification chain. This is
error-prone as evident by this patch and also not symmetric with the
registration path where a listener receives a dump of all the existing
nexthops.

Therefore, fix this problem by replaying delete notifications for the
listener being unregistered. This is symmetric to the registration path
and also consistent with the netdev notification chain.

The above means that unregister_nexthop_notifier(), like
register_nexthop_notifier(), will have to take RTNL in order to iterate
over the existing nexthops and that any callers of the function cannot
hold RTNL. This is true for mlxsw and netdevsim, but not for the VXLAN
driver. To avoid a deadlock, change the latter to unregister its nexthop
listener without holding RTNL, making it symmetric to the registration
path.

[1]
unreferenced object 0xffff88806173d600 (size 512):
  comm "syz-executor.0", pid 1290, jiffies 4295583142 (age 143.507s)
  hex dump (first 32 bytes):
    41 9d 1e 60 80 88 ff ff 08 d6 73 61 80 88 ff ff  A..`......sa....
    08 d6 73 61 80 88 ff ff 01 00 00 00 00 00 00 00  ..sa............
  backtrace:
    [<ffffffff81a6b576>] kmemleak_alloc_recursive include/linux/kmemleak.h:43 [inline]
    [<ffffffff81a6b576>] slab_post_alloc_hook+0x96/0x490 mm/slab.h:522
    [<ffffffff81a716d3>] slab_alloc_node mm/slub.c:3206 [inline]
    [<ffffffff81a716d3>] slab_alloc mm/slub.c:3214 [inline]
    [<ffffffff81a716d3>] kmem_cache_alloc_trace+0x163/0x370 mm/slub.c:3231
    [<ffffffff82e8681a>] kmalloc include/linux/slab.h:591 [inline]
    [<ffffffff82e8681a>] kzalloc include/linux/slab.h:721 [inline]
    [<ffffffff82e8681a>] mlxsw_sp_nexthop_obj_group_create drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c:4918 [inline]
    [<ffffffff82e8681a>] mlxsw_sp_nexthop_obj_new drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c:5054 [inline]
    [<ffffffff82e8681a>] mlxsw_sp_nexthop_obj_event+0x59a/0x2910 drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c:5239
    [<ffffffff813ef67d>] notifier_call_chain+0xbd/0x210 kernel/notifier.c:83
    [<ffffffff813f0662>] blocking_notifier_call_chain kernel/notifier.c:318 [inline]
    [<ffffffff813f0662>] blocking_notifier_call_chain+0x72/0xa0 kernel/notifier.c:306
    [<ffffffff8384b9c6>] call_nexthop_notifiers+0x156/0x310 net/ipv4/nexthop.c:244
    [<ffffffff83852bd8>] insert_nexthop net/ipv4/nexthop.c:2336 [inline]
    [<ffffffff83852bd8>] nexthop_add net/ipv4/nexthop.c:2644 [inline]
    [<ffffffff83852bd8>] rtm_new_nexthop+0x14e8/0x4d10 net/ipv4/nexthop.c:2913
    [<ffffffff833e9a78>] rtnetlink_rcv_msg+0x448/0xbf0 net/core/rtnetlink.c:5572
    [<ffffffff83608703>] netlink_rcv_skb+0x173/0x480 net/netlink/af_netlink.c:2504
    [<ffffffff833de032>] rtnetlink_rcv+0x22/0x30 net/core/rtnetlink.c:5590
    [<ffffffff836069de>] netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline]
    [<ffffffff836069de>] netlink_unicast+0x5ae/0x7f0 net/netlink/af_netlink.c:1340
    [<ffffffff83607501>] netlink_sendmsg+0x8e1/0xe30 net/netlink/af_netlink.c:1929
    [<ffffffff832fde84>] sock_sendmsg_nosec net/socket.c:704 [inline]
    [<ffffffff832fde84>] sock_sendmsg net/socket.c:724 [inline]
    [<ffffffff832fde84>] ____sys_sendmsg+0x874/0x9f0 net/socket.c:2409
    [<ffffffff83304a44>] ___sys_sendmsg+0x104/0x170 net/socket.c:2463
    [<ffffffff83304c01>] __sys_sendmsg+0x111/0x1f0 net/socket.c:2492
    [<ffffffff83304d5d>] __do_sys_sendmsg net/socket.c:2501 [inline]
    [<ffffffff83304d5d>] __se_sys_sendmsg net/socket.c:2499 [inline]
    [<ffffffff83304d5d>] __x64_sys_sendmsg+0x7d/0xc0 net/socket.c:2499

Fixes: 2a014b200b ("mlxsw: spectrum_router: Add support for nexthop objects")
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-09-23 12:33:22 +01:00
..
6lowpan 6lowpan: iphc: Fix an off-by-one check of array index 2021-07-22 16:19:03 +02:00
9p net/9p: increase default msize to 128k 2021-09-05 08:36:44 +09:00
802 net: 802: remove dead leftover after ipx driver removal 2021-08-13 16:30:35 -07:00
8021q dev_ioctl: split out ndo_eth_ioctl 2021-07-27 20:11:45 +01:00
appletalk net: socket: rework compat_ifreq_ioctl() 2021-07-23 14:20:25 +01:00
atm atm: Use list_for_each_entry() to simplify code in resources.c 2021-06-10 14:08:09 -07:00
ax25 ax25: use skb_expand_head 2021-08-03 11:21:39 +01:00
batman-adv Kbuild updates for v5.15 2021-09-03 15:33:47 -07:00
bluetooth TTY / Serial patches for 5.15-rc1 2021-09-01 09:51:16 -07:00
bpf bpf: Refactor BPF_PROG_RUN into a function 2021-08-17 00:45:07 +02:00
bpfilter bpfilter: Specify the log level for the kmsg message 2021-06-25 13:13:50 +02:00
bridge net: bridge: mcast: fix vlan port router deadlock 2021-09-03 13:43:19 +01:00
caif net-caif: avoid user-triggerable WARN_ON(1) 2021-09-14 12:51:15 +01:00
can net: Remove redundant if statements 2021-08-05 13:27:50 +01:00
ceph Networking changes for 5.14. 2021-06-30 15:51:09 -07:00
core napi: fix race inside napi_enable 2021-09-20 09:41:29 +01:00
dcb
dccp dccp: don't duplicate ccid when cloning dccp sock 2021-09-08 11:28:35 +01:00
decnet net: Remove redundant if statements 2021-08-05 13:27:50 +01:00
dns_resolver
dsa net: dsa: don't allocate the slave_mii_bus using devres 2021-09-21 13:52:16 +01:00
ethernet move netdev_boot_setup into Space.c 2021-08-03 13:05:26 +01:00
ethtool ethtool: extend coalesce setting uAPI with CQE mode 2021-08-24 07:38:29 -07:00
hsr net: hsr: don't check sequence number if tag removal is offloaded 2021-06-16 12:13:01 -07:00
ieee802154 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2021-08-13 06:41:22 -07:00
ife
ipv4 nexthop: Fix memory leaks in nexthop notification chain listeners 2021-09-23 12:33:22 +01:00
ipv6 ipv6: delay fib6_sernum increase in fib6_add 2021-09-13 13:00:53 +01:00
iucv net/iucv: Replace deprecated CPU-hotplug functions. 2021-08-09 10:13:32 +01:00
kcm net: sock: introduce sk_error_report 2021-06-29 11:28:21 -07:00
key
l2tp net/l2tp: Fix reference count leak in l2tp_udp_recv_core 2021-09-09 11:00:20 +01:00
l3mdev
lapb net: lapb: Use list_for_each_entry() to simplify code in lapb_iface.c 2021-06-08 16:31:25 -07:00
llc net: Remove redundant if statements 2021-08-05 13:27:50 +01:00
mac80211 mac80211: parse transmit power envelope element 2021-08-26 10:18:56 +02:00
mac802154 ieee802154: Remove redundant initialization of variable ret 2021-09-07 14:06:08 +01:00
mctp mctp: perform route destruction under RCU read lock 2021-09-08 11:29:16 +01:00
mpls mpls: defer ttl decrement in mpls_forward() 2021-07-23 17:17:56 +01:00
mptcp mptcp: ensure tx skbs always have the MPTCP ext 2021-09-22 14:39:41 +01:00
ncsi net/ncsi: add get MAC address command to get Intel i210 MAC address 2021-09-01 17:18:56 -07:00
netfilter Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf 2021-09-03 16:20:37 -07:00
netlabel net: fix NULL pointer reference in cipso_v4_doi_free 2021-08-30 12:23:18 +01:00
netlink net: netlink: Remove unused function 2021-07-30 18:35:47 +02:00
netrom net: Remove redundant if statements 2021-08-05 13:27:50 +01:00
nfc net: in_irq() cleanup 2021-08-13 14:09:19 -07:00
nsh
openvswitch Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2021-08-19 18:09:18 -07:00
packet net/packet: clarify source of pr_*() messages 2021-09-10 10:00:59 +01:00
phonet net: Remove redundant if statements 2021-08-05 13:27:50 +01:00
psample
qrtr net: qrtr: revert check in qrtr_endpoint_post() 2021-09-02 11:37:02 +01:00
rds net/rds: dma_map_sg is entitled to merge entries 2021-08-18 15:35:50 -07:00
rfkill
rose
rxrpc net: RxRPC: make dependent Kconfig symbols be shown indented 2021-08-18 10:12:11 +01:00
sched fq_codel: reject silly quantum parameters 2021-09-04 10:49:46 +01:00
sctp sctp: move the active_key update after sh_keys is added 2021-08-03 11:43:43 +01:00
smc net/smc: fix 'workqueue leaked lock' in smc_conn_abort_work 2021-09-21 10:54:16 +01:00
strparser net: sock: introduce sk_error_report 2021-06-29 11:28:21 -07:00
sunrpc Critical bug fixes: 2021-09-08 15:55:42 -07:00
switchdev net: make switchdev_bridge_port_{,unoffload} loosely coupled with the bridge 2021-08-04 12:35:07 +01:00
tipc tipc: increase timeout in tipc_sk_enqueue() 2021-09-13 12:43:10 +01:00
tls Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2021-06-29 15:45:27 -07:00
unix net/af_unix: fix a data-race in unix_dgram_poll 2021-09-09 10:57:52 +01:00
vmw_vsock af_vsock: rename variables in receive loop 2021-09-06 02:25:16 -04:00
wireless cfg80211: use wiphy DFS domain if it is self-managed 2021-08-26 11:04:55 +02:00
x25 net: x25: Use list_for_each_entry() to simplify code in x25_route.c 2021-06-10 14:08:09 -07:00
xdp Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2021-06-29 15:45:27 -07:00
xfrm Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ 2021-08-27 11:16:29 +01:00
compat.c net: Return the correct errno code 2021-06-03 15:13:56 -07:00
devres.c net: devres: Correct a grammatical error 2021-06-11 12:55:28 -07:00
Kconfig mctp: Add MCTP base 2021-07-29 15:06:49 +01:00
Makefile mctp: Add MCTP base 2021-07-29 15:06:49 +01:00
socket.c Core: 2021-08-31 16:43:06 -07:00
sysctl_net.c