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Lin Ma 9ded5ae40f nfc: nci: add flush_workqueue to prevent uaf 
[ Upstream commit ef27324e2c ]

Our detector found a concurrent use-after-free bug when detaching an
NCI device. The main reason for this bug is the unexpected scheduling
between the used delayed mechanism (timer and workqueue).

The race can be demonstrated below:

Thread-1                           Thread-2
                                 | nci_dev_up()
                                 |   nci_open_device()
                                 |     __nci_request(nci_reset_req)
                                 |       nci_send_cmd
                                 |         queue_work(cmd_work)
nci_unregister_device()          |
  nci_close_device()             | ...
    del_timer_sync(cmd_timer)[1] |
...                              | Worker
nci_free_device()                | nci_cmd_work()
  kfree(ndev)[3]                 |   mod_timer(cmd_timer)[2]

In short, the cleanup routine thought that the cmd_timer has already
been detached by [1] but the mod_timer can re-attach the timer [2], even
it is already released [3], resulting in UAF.

This UAF is easy to trigger, crash trace by POC is like below

[   66.703713] ==================================================================
[   66.703974] BUG: KASAN: use-after-free in enqueue_timer+0x448/0x490
[   66.703974] Write of size 8 at addr ffff888009fb7058 by task kworker/u4:1/33
[   66.703974]
[   66.703974] CPU: 1 PID: 33 Comm: kworker/u4:1 Not tainted 5.18.0-rc2 #5
[   66.703974] Workqueue: nfc2_nci_cmd_wq nci_cmd_work
[   66.703974] Call Trace:
[   66.703974]  <TASK>
[   66.703974]  dump_stack_lvl+0x57/0x7d
[   66.703974]  print_report.cold+0x5e/0x5db
[   66.703974]  ? enqueue_timer+0x448/0x490
[   66.703974]  kasan_report+0xbe/0x1c0
[   66.703974]  ? enqueue_timer+0x448/0x490
[   66.703974]  enqueue_timer+0x448/0x490
[   66.703974]  __mod_timer+0x5e6/0xb80
[   66.703974]  ? mark_held_locks+0x9e/0xe0
[   66.703974]  ? try_to_del_timer_sync+0xf0/0xf0
[   66.703974]  ? lockdep_hardirqs_on_prepare+0x17b/0x410
[   66.703974]  ? queue_work_on+0x61/0x80
[   66.703974]  ? lockdep_hardirqs_on+0xbf/0x130
[   66.703974]  process_one_work+0x8bb/0x1510
[   66.703974]  ? lockdep_hardirqs_on_prepare+0x410/0x410
[   66.703974]  ? pwq_dec_nr_in_flight+0x230/0x230
[   66.703974]  ? rwlock_bug.part.0+0x90/0x90
[   66.703974]  ? _raw_spin_lock_irq+0x41/0x50
[   66.703974]  worker_thread+0x575/0x1190
[   66.703974]  ? process_one_work+0x1510/0x1510
[   66.703974]  kthread+0x2a0/0x340
[   66.703974]  ? kthread_complete_and_exit+0x20/0x20
[   66.703974]  ret_from_fork+0x22/0x30
[   66.703974]  </TASK>
[   66.703974]
[   66.703974] Allocated by task 267:
[   66.703974]  kasan_save_stack+0x1e/0x40
[   66.703974]  __kasan_kmalloc+0x81/0xa0
[   66.703974]  nci_allocate_device+0xd3/0x390
[   66.703974]  nfcmrvl_nci_register_dev+0x183/0x2c0
[   66.703974]  nfcmrvl_nci_uart_open+0xf2/0x1dd
[   66.703974]  nci_uart_tty_ioctl+0x2c3/0x4a0
[   66.703974]  tty_ioctl+0x764/0x1310
[   66.703974]  __x64_sys_ioctl+0x122/0x190
[   66.703974]  do_syscall_64+0x3b/0x90
[   66.703974]  entry_SYSCALL_64_after_hwframe+0x44/0xae
[   66.703974]
[   66.703974] Freed by task 406:
[   66.703974]  kasan_save_stack+0x1e/0x40
[   66.703974]  kasan_set_track+0x21/0x30
[   66.703974]  kasan_set_free_info+0x20/0x30
[   66.703974]  __kasan_slab_free+0x108/0x170
[   66.703974]  kfree+0xb0/0x330
[   66.703974]  nfcmrvl_nci_unregister_dev+0x90/0xd0
[   66.703974]  nci_uart_tty_close+0xdf/0x180
[   66.703974]  tty_ldisc_kill+0x73/0x110
[   66.703974]  tty_ldisc_hangup+0x281/0x5b0
[   66.703974]  __tty_hangup.part.0+0x431/0x890
[   66.703974]  tty_release+0x3a8/0xc80
[   66.703974]  __fput+0x1f0/0x8c0
[   66.703974]  task_work_run+0xc9/0x170
[   66.703974]  exit_to_user_mode_prepare+0x194/0x1a0
[   66.703974]  syscall_exit_to_user_mode+0x19/0x50
[   66.703974]  do_syscall_64+0x48/0x90
[   66.703974]  entry_SYSCALL_64_after_hwframe+0x44/0xae

To fix the UAF, this patch adds flush_workqueue() to ensure the
nci_cmd_work is finished before the following del_timer_sync.
This combination will promise the timer is actually detached.

Fixes: 6a2968aaf5 ("NFC: basic NCI protocol implementation")
Signed-off-by: Lin Ma <linma@zju.edu.cn>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-04-20 09:34:13 +02:00
..
6lowpan
9p xen/9p: use alloc/free_pages_exact() 2022-03-11 12:22:36 +01:00
802 net: 802: remove dead leftover after ipx driver removal 2021-08-13 16:30:35 -07:00
8021q net: vlan: fix underflow for the real_dev refcnt 2021-12-01 09:04:53 +01:00
appletalk
atm
ax25 ax25: Fix NULL pointer dereference in ax25_kill_by_device 2022-03-16 14:23:38 +01:00
batman-adv ipv6: make mc_forwarding atomic 2022-04-13 20:59:03 +02:00
bluetooth Bluetooth: Fix use after free in hci_send_acl 2022-04-13 20:59:09 +02:00
bpf bpf: Make remote_port field in struct bpf_sk_lookup 16-bit wide 2022-04-13 20:59:25 +02:00
bpfilter
bridge net: bridge: multicast: notify switchdev driver whenever MC processing gets disabled 2022-02-23 12:03:13 +01:00
caif net-caif: avoid user-triggerable WARN_ON(1) 2021-09-14 12:51:15 +01:00
can can: isotp: set default value for N_As to 50 micro seconds 2022-04-13 20:59:08 +02:00
ceph
core net/sched: flower: fix parsing of ethertype following VLAN header 2022-04-20 09:34:09 +02:00
dcb net: dcb: disable softirqs in dcbnl_flush_dev() 2022-03-08 19:12:52 +01:00
dccp tcp: switch orphan_count to bare per-cpu counters 2021-11-18 19:16:33 +01:00
decnet
dns_resolver
dsa net: dsa: fix panic on shutdown if multi-chip tree failed to probe 2022-04-08 14:23:43 +02:00
ethernet
ethtool ethtool: do not perform operations on net devices being unregistered 2021-12-14 10:57:09 +01:00
hsr
ieee802154 net: ieee802154: Return meaningful error codes from the netlink helpers 2022-02-08 18:34:09 +01:00
ife
ipv4 net: ipv4: fix route with nexthop object delete warning 2022-04-13 20:59:16 +02:00
ipv6 ipv6: Fix stats accounting in ip6_pkt_drop 2022-04-13 20:59:18 +02:00
iucv
kcm
key af_key: add __GFP_ZERO flag for compose_sadb_supported in function pfkey_register 2022-04-08 14:22:47 +02:00
l2tp net/l2tp: Fix reference count leak in l2tp_udp_recv_core 2021-09-09 11:00:20 +01:00
l3mdev
lapb
llc llc: only change llc->dev when bind() succeeds 2022-03-28 09:58:46 +02:00
mac80211 mac80211: limit bandwidth in HE capabilities 2022-04-08 14:23:28 +02:00
mac802154 ieee802154: Remove redundant initialization of variable ret 2021-09-07 14:06:08 +01:00
mctp mctp: Fix check for dev_hard_header() result 2022-04-13 20:59:16 +02:00
mpls net: mpls: Fix notifications when deleting a device 2021-12-08 09:04:47 +01:00
mptcp mptcp: Correctly set DATA_FIN timeout when number of retransmits is large 2022-03-08 19:12:48 +01:00
ncsi net/ncsi: check for error return from call to nla_put_u32 2022-01-05 12:42:37 +01:00
netfilter netfilter: nf_tables: nft_parse_register can return a negative value 2022-04-20 09:34:12 +02:00
netlabel netlabel: fix out-of-bounds memory accesses 2022-04-13 20:59:10 +02:00
netlink af_netlink: Fix shift out of bounds in group mask calculation 2022-04-08 14:23:42 +02:00
netrom netrom: fix api breakage in nr_setsockopt() 2022-01-27 11:04:00 +01:00
nfc nfc: nci: add flush_workqueue to prevent uaf 2022-04-20 09:34:13 +02:00
nsh
openvswitch net: openvswitch: fix leak of nested actions 2022-04-13 20:59:19 +02:00
packet net/packet: fix slab-out-of-bounds access in packet_recvmsg() 2022-03-23 09:16:41 +01:00
phonet phonet: refcount leak in pep_sock_accep 2022-01-11 15:35:16 +01:00
psample
qrtr net: qrtr: revert check in qrtr_endpoint_post() 2021-09-02 11:37:02 +01:00
rds rds: memory leak in __rds_conn_create() 2021-12-22 09:32:42 +01:00
rfkill rfkill: make new event layout opt-in 2022-04-08 14:23:00 +02:00
rose
rxrpc rxrpc: fix a race in rxrpc_exit_net() 2022-04-13 20:59:19 +02:00
sched net/sched: taprio: Check if socket flags are valid 2022-04-20 09:34:10 +02:00
sctp sctp: Initialize daddr on peeled off socket 2022-04-20 09:34:12 +02:00
smc net/smc: Fix NULL pointer dereference in smc_pnet_find_ib() 2022-04-20 09:34:11 +02:00
strparser bpf: sockmap, strparser, and tls are reusing qdisc_skb_cb and colliding 2021-11-18 19:17:11 +01:00
sunrpc SUNRPC: Don't call connect() more than once on a TCP socket 2022-04-13 20:59:26 +02:00
switchdev
tipc tipc: fix the timer expires after interval 100ms 2022-04-08 14:23:43 +02:00
tls net/tls: fix slab-out-of-bounds bug in decrypt_internal 2022-04-13 20:59:15 +02:00
unix af_unix: Support POLLPRI for OOB. 2022-04-08 14:24:14 +02:00
vmw_vsock vsock/virtio: enable VQs early on probe 2022-04-08 14:23:51 +02:00
wireless cfg80211: hold bss_lock while updating nontrans_list 2022-04-20 09:34:10 +02:00
x25 net/x25: Fix null-ptr-deref caused by x25_disconnect 2022-04-08 14:23:53 +02:00
xdp xsk: Fix race at socket teardown 2022-04-08 14:23:36 +02:00
xfrm xfrm: fix tunnel model fragmentation behavior 2022-04-08 14:22:46 +02:00
compat.c
devres.c
Kconfig
Makefile
socket.c net: fix SOF_TIMESTAMPING_BIND_PHC to work with multiple sockets 2022-01-27 11:03:52 +01:00
sysctl_net.c