Duoming Zhou 82e31755e5 ax25: Fix UAF bugs in ax25 timers ... There are race conditions that may lead to UAF bugs in ax25_heartbeat_expiry(), ax25_t1timer_expiry(), ax25_t2timer_expiry(), ax25_t3timer_expiry() and ax25_idletimer_expiry(), when we call ax25_release() to deallocate ax25_dev. One of the UAF bugs caused by ax25_release() is shown below: (Thread 1) | (Thread 2) ax25_dev_device_up() //(1) | ... | ax25_kill_by_device() ax25_bind() //(2) | ax25_connect() | ... ax25_std_establish_data_link() | ax25_start_t1timer() | ax25_dev_device_down() //(3) mod_timer(&ax25->t1timer,..) | | ax25_release() (wait a time) | ... | ax25_dev_put(ax25_dev) //(4)FREE ax25_t1timer_expiry() | ax25->ax25_dev->values[..] //USE| ... ... | We increase the refcount of ax25_dev in position (1) and (2), and decrease the refcount of ax25_dev in position (3) and (4). The ax25_dev will be freed in position (4) and be used in ax25_t1timer_expiry(). The fail log is shown below: ============================================================== [ 106.116942] BUG: KASAN: use-after-free in ax25_t1timer_expiry+0x1c/0x60 [ 106.116942] Read of size 8 at addr ffff88800bda9028 by task swapper/0/0 [ 106.116942] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.17.0-06123-g0905eec574 [ 106.116942] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-14 [ 106.116942] Call Trace: ... [ 106.116942] ax25_t1timer_expiry+0x1c/0x60 [ 106.116942] call_timer_fn+0x122/0x3d0 [ 106.116942] __run_timers.part.0+0x3f6/0x520 [ 106.116942] run_timer_softirq+0x4f/0xb0 [ 106.116942] __do_softirq+0x1c2/0x651 ... This patch adds del_timer_sync() in ax25_release(), which could ensure that all timers stop before we deallocate ax25_dev. Signed-off-by: Duoming Zhou <duoming@zju.edu.cn> Signed-off-by: Paolo Abeni <pabeni@redhat.com>		2022-03-29 10:24:34 +02:00
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af_ax25.c	ax25: Fix UAF bugs in ax25 timers	2022-03-29 10:24:34 +02:00
ax25_addr.c
ax25_dev.c	ax25: fix reference count leaks of ax25_dev	2022-02-03 14:20:36 -08:00
ax25_ds_in.c
ax25_ds_subr.c
ax25_ds_timer.c
ax25_iface.c	ax25: constify dev_addr passing	2021-10-13 09:40:45 -07:00
ax25_in.c	ax25: constify dev_addr passing	2021-10-13 09:40:45 -07:00
ax25_ip.c
ax25_out.c	ax25: constify dev_addr passing	2021-10-13 09:40:45 -07:00
ax25_route.c	Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net	2022-02-03 17:36:16 -08:00
ax25_std_in.c
ax25_std_subr.c
ax25_std_timer.c
ax25_subr.c	ax25: Fix NULL pointer dereferences in ax25 timers	2022-03-21 10:56:19 +00:00
ax25_timer.c
ax25_uid.c
Kconfig
Makefile
sysctl_net_ax25.c