From: Oliver Hartkopp <socketcan@xxxxxxxxxxxx> commit 14a4696bc3118ba49da28f79280e1d55603aa737 upstream. When closing the isotp socket, the potentially running hrtimers are canceled before removing the subscription for CAN identifiers via can_rx_unregister(). This may lead to an unintended (re)start of a hrtimer in isotp_rcv_cf() and isotp_rcv_fc() in the case that a CAN frame is received by isotp_rcv() while the subscription removal is processed. However, isotp_rcv() 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. This prevents the reception of CAN frames after hrtimer_cancel() and therefore the unintended (re)start of the hrtimers. Link: https://lore.kernel.org/r/20210618173713.2296-1-socketcan@xxxxxxxxxxxx Fixes: e057dd3fc20f ("can: add ISO 15765-2:2016 transport protocol") Cc: linux-stable <stable@xxxxxxxxxxxxxxx> Signed-off-by: Oliver Hartkopp <socketcan@xxxxxxxxxxxx> Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/can/isotp.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) --- a/net/can/isotp.c +++ b/net/can/isotp.c @@ -1023,9 +1023,6 @@ static int isotp_release(struct socket * lock_sock(sk); - hrtimer_cancel(&so->txtimer); - hrtimer_cancel(&so->rxtimer); - /* remove current filters & unregister */ if (so->bound) { if (so->ifindex) { @@ -1037,10 +1034,14 @@ static int isotp_release(struct socket * SINGLE_MASK(so->rxid), isotp_rcv, sk); dev_put(dev); + synchronize_rcu(); } } } + hrtimer_cancel(&so->txtimer); + hrtimer_cancel(&so->rxtimer); + so->ifindex = 0; so->bound = 0;
