Archivos anuales: 2024

wifi: mac80211: Fix deadlock in ieee80211_sta_ps_deliver_wakeup()

The ieee80211_sta_ps_deliver_wakeup() function takes sta->ps_lock to
synchronizes with ieee80211_tx_h_unicast_ps_buf() which is called from
softirq context. However using only spin_lock() to get sta->ps_lock in
ieee80211_sta_ps_deliver_wakeup() does not prevent softirq to execute
on this same CPU, to run ieee80211_tx_h_unicast_ps_buf() and try to
take this same lock ending in deadlock. Below is an example of rcu stall
that arises in such situation.

rcu: INFO: rcu_sched self-detected stall on CPU
rcu: 2-….: (42413413 ticks this GP) idle=b154/1/0x4000000000000000 softirq=1763/1765 fqs=21206996
rcu: (t=42586894 jiffies g=2057 q=362405 ncpus=4)
CPU: 2 PID: 719 Comm: wpa_supplicant Tainted: G W 6.4.0-02158-g1b062f552873 #742
Hardware name: RPT (r1) (DT)
pstate: 00000005 (nzcv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=–)
pc : queued_spin_lock_slowpath+0x58/0x2d0
lr : invoke_tx_handlers_early+0x5b4/0x5c0
sp : ffff00001ef64660
x29: ffff00001ef64660 x28: ffff000009bc1070 x27: ffff000009bc0ad8
x26: ffff000009bc0900 x25: ffff00001ef647a8 x24: 0000000000000000
x23: ffff000009bc0900 x22: ffff000009bc0900 x21: ffff00000ac0e000
x20: ffff00000a279e00 x19: ffff00001ef646e8 x18: 0000000000000000
x17: ffff800016468000 x16: ffff00001ef608c0 x15: 0010533c93f64f80
x14: 0010395c9faa3946 x13: 0000000000000000 x12: 00000000fa83b2da
x11: 000000012edeceea x10: ffff0000010fbe00 x9 : 0000000000895440
x8 : 000000000010533c x7 : ffff00000ad8b740 x6 : ffff00000c350880
x5 : 0000000000000007 x4 : 0000000000000001 x3 : 0000000000000000
x2 : 0000000000000000 x1 : 0000000000000001 x0 : ffff00000ac0e0e8
Call trace:
queued_spin_lock_slowpath+0x58/0x2d0
ieee80211_tx+0x80/0x12c
ieee80211_tx_pending+0x110/0x278
tasklet_action_common.constprop.0+0x10c/0x144
tasklet_action+0x20/0x28
_stext+0x11c/0x284
____do_softirq+0xc/0x14
call_on_irq_stack+0x24/0x34
do_softirq_own_stack+0x18/0x20
do_softirq+0x74/0x7c
__local_bh_enable_ip+0xa0/0xa4
_ieee80211_wake_txqs+0x3b0/0x4b8
__ieee80211_wake_queue+0x12c/0x168
ieee80211_add_pending_skbs+0xec/0x138
ieee80211_sta_ps_deliver_wakeup+0x2a4/0x480
ieee80211_mps_sta_status_update.part.0+0xd8/0x11c
ieee80211_mps_sta_status_update+0x18/0x24
sta_apply_parameters+0x3bc/0x4c0
ieee80211_change_station+0x1b8/0x2dc
nl80211_set_station+0x444/0x49c
genl_family_rcv_msg_doit.isra.0+0xa4/0xfc
genl_rcv_msg+0x1b0/0x244
netlink_rcv_skb+0x38/0x10c
genl_rcv+0x34/0x48
netlink_unicast+0x254/0x2bc
netlink_sendmsg+0x190/0x3b4
____sys_sendmsg+0x1e8/0x218
___sys_sendmsg+0x68/0x8c
__sys_sendmsg+0x44/0x84
__arm64_sys_sendmsg+0x20/0x28
do_el0_svc+0x6c/0xe8
el0_svc+0x14/0x48
el0t_64_sync_handler+0xb0/0xb4
el0t_64_sync+0x14c/0x150

Using spin_lock_bh()/spin_unlock_bh() instead prevents softirq to raise
on the same CPU that is holding the lock.

wifi: cfg80211: Lock wiphy in cfg80211_get_station

Wiphy should be locked before calling rdev_get_station() (see lockdep
assert in ieee80211_get_station()).

This fixes the following kernel NULL dereference:

Unable to handle kernel NULL pointer dereference at virtual address 0000000000000050
Mem abort info:
ESR = 0x0000000096000006
EC = 0x25: DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
FSC = 0x06: level 2 translation fault
Data abort info:
ISV = 0, ISS = 0x00000006
CM = 0, WnR = 0
user pgtable: 4k pages, 48-bit VAs, pgdp=0000000003001000
[0000000000000050] pgd=0800000002dca003, p4d=0800000002dca003, pud=08000000028e9003, pmd=0000000000000000
Internal error: Oops: 0000000096000006 [#1] SMP
Modules linked in: netconsole dwc3_meson_g12a dwc3_of_simple dwc3 ip_gre gre ath10k_pci ath10k_core ath9k ath9k_common ath9k_hw ath
CPU: 0 PID: 1091 Comm: kworker/u8:0 Not tainted 6.4.0-02144-g565f9a3a7911-dirty #705
Hardware name: RPT (r1) (DT)
Workqueue: bat_events batadv_v_elp_throughput_metric_update
pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=–)
pc : ath10k_sta_statistics+0x10/0x2dc [ath10k_core]
lr : sta_set_sinfo+0xcc/0xbd4
sp : ffff000007b43ad0
x29: ffff000007b43ad0 x28: ffff0000071fa900 x27: ffff00000294ca98
x26: ffff000006830880 x25: ffff000006830880 x24: ffff00000294c000
x23: 0000000000000001 x22: ffff000007b43c90 x21: ffff800008898acc
x20: ffff00000294c6e8 x19: ffff000007b43c90 x18: 0000000000000000
x17: 445946354d552d78 x16: 62661f7200000000 x15: 57464f445946354d
x14: 0000000000000000 x13: 00000000000000e3 x12: d5f0acbcebea978e
x11: 00000000000000e3 x10: 000000010048fe41 x9 : 0000000000000000
x8 : ffff000007b43d90 x7 : 000000007a1e2125 x6 : 0000000000000000
x5 : ffff0000024e0900 x4 : ffff800000a0250c x3 : ffff000007b43c90
x2 : ffff00000294ca98 x1 : ffff000006831920 x0 : 0000000000000000
Call trace:
ath10k_sta_statistics+0x10/0x2dc [ath10k_core]
sta_set_sinfo+0xcc/0xbd4
ieee80211_get_station+0x2c/0x44
cfg80211_get_station+0x80/0x154
batadv_v_elp_get_throughput+0x138/0x1fc
batadv_v_elp_throughput_metric_update+0x1c/0xa4
process_one_work+0x1ec/0x414
worker_thread+0x70/0x46c
kthread+0xdc/0xe0
ret_from_fork+0x10/0x20
Code: a9bb7bfd 910003fd a90153f3 f9411c40 (f9402814)

This happens because STA has time to disconnect and reconnect before
batadv_v_elp_throughput_metric_update() delayed work gets scheduled. In
this situation, ath10k_sta_state() can be in the middle of resetting
arsta data when the work queue get chance to be scheduled and ends up
accessing it. Locking wiphy prevents that.

ax25: Fix refcount imbalance on inbound connections

When releasing a socket in ax25_release(), we call netdev_put() to
decrease the refcount on the associated ax.25 device. However, the
execution path for accepting an incoming connection never calls
netdev_hold(). This imbalance leads to refcount errors, and ultimately
to kernel crashes.

A typical call trace for the above situation will start with one of the
following errors:

refcount_t: decrement hit 0; leaking memory.
refcount_t: underflow; use-after-free.

And will then have a trace like:

Call Trace:

? show_regs+0x64/0x70
? __warn+0x83/0x120
? refcount_warn_saturate+0xb2/0x100
? report_bug+0x158/0x190
? prb_read_valid+0x20/0x30
? handle_bug+0x3e/0x70
? exc_invalid_op+0x1c/0x70
? asm_exc_invalid_op+0x1f/0x30
? refcount_warn_saturate+0xb2/0x100
? refcount_warn_saturate+0xb2/0x100
ax25_release+0x2ad/0x360
__sock_release+0x35/0xa0
sock_close+0x19/0x20
[…]

On reboot (or any attempt to remove the interface), the kernel gets
stuck in an infinite loop:

unregister_netdevice: waiting for ax0 to become free. Usage count = 0

This patch corrects these issues by ensuring that we call netdev_hold()
and ax25_dev_hold() for new connections in ax25_accept(). This makes the
logic leading to ax25_accept() match the logic for ax25_bind(): in both
cases we increment the refcount, which is ultimately decremented in
ax25_release().

bpf: Fix a potential use-after-free in bpf_link_free()

After commit 1a80dbcb2dba, bpf_link can be freed by
link->ops->dealloc_deferred, but the code still tests and uses
link->ops->dealloc afterward, which leads to a use-after-free as
reported by syzbot. Actually, one of them should be sufficient, so
just call one of them instead of both. Also add a WARN_ON() in case
of any problematic implementation.

bpf: Set run context for rawtp test_run callback

syzbot reported crash when rawtp program executed through the
test_run interface calls bpf_get_attach_cookie helper or any
other helper that touches task->bpf_ctx pointer.

Setting the run context (task->bpf_ctx pointer) for test_run
callback.