linux/net/can
Thadeu Lima de Souza Cascardo d5f9023fa6 can: bcm: delay release of struct bcm_op after synchronize_rcu()
can_rx_register() callbacks may be called concurrently to the call to
can_rx_unregister(). The callbacks and callback data, though, are
protected by RCU and the struct sock reference count.

So the callback data is really attached to the life of sk, meaning
that it should be released on sk_destruct. However, bcm_remove_op()
calls tasklet_kill(), and RCU callbacks may be called under RCU
softirq, so that cannot be used on kernels before the introduction of
HRTIMER_MODE_SOFT.

However, bcm_rx_handler() is called under RCU protection, so after
calling can_rx_unregister(), we may call synchronize_rcu() in order to
wait for any RCU read-side critical sections to finish. That is,
bcm_rx_handler() won't be called anymore for those ops. So, we only
free them, after we do that synchronize_rcu().

Fixes: ffd980f976 ("[CAN]: Add broadcast manager (bcm) protocol")
Link: https://lore.kernel.org/r/20210619161813.2098382-1-cascardo@canonical.com
Cc: linux-stable <stable@vger.kernel.org>
Reported-by: syzbot+0f7e7e5e2f4f40fa89c0@syzkaller.appspotmail.com
Reported-by: Norbert Slusarek <nslusarek@gmx.net>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Acked-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2021-06-19 23:47:32 +02:00
..
j1939 can: j1939: fix Use-after-Free, hold skb ref while in use 2021-06-16 12:52:18 +02:00
af_can.c net: introduce CAN specific pointer in the struct net_device 2021-02-24 14:32:15 -08:00
af_can.h can: introduce CAN midlayer private and allocate it automatically 2019-09-04 13:29:14 +02:00
bcm.c can: bcm: delay release of struct bcm_op after synchronize_rcu() 2021-06-19 23:47:32 +02:00
gw.c can: gw: fix typo 2021-01-27 10:01:46 +01:00
isotp.c can: bcm/raw/isotp: use per module netdevice notifier 2021-06-16 12:52:18 +02:00
Kconfig net: remove redundant 'depends on NET' 2021-01-27 17:04:12 -08:00
Makefile can: add ISO 15765-2:2016 transport protocol 2020-10-07 23:18:33 +02:00
proc.c can: proc: fix rcvlist_* header alignment on 64-bit system 2021-04-25 19:43:00 +02:00
raw.c can: bcm/raw/isotp: use per module netdevice notifier 2021-06-16 12:52:18 +02:00