On Fri, Aug 05, 2022 at 06:02:16PM +0300, Fedor Pchelkin wrote: > We need to drop skb references taken in j1939_session_skb_queue() when > destroying a session in j1939_session_destroy(). Otherwise those skbs > would be lost. > > Link to Syzkaller info and repro: https://forge.ispras.ru/issues/11743. > > Found by Linux Verification Center (linuxtesting.org) with Syzkaller. > > Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol") > Suggested-by: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx> > Signed-off-by: Fedor Pchelkin <pchelkin@xxxxxxxxx> > Signed-off-by: Alexey Khoroshilov <khoroshilov@xxxxxxxxx> Acked-by: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx> > --- > net/can/j1939/transport.c | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/net/can/j1939/transport.c b/net/can/j1939/transport.c > index 307ee1174a6e..d7d86c944d76 100644 > --- a/net/can/j1939/transport.c > +++ b/net/can/j1939/transport.c > @@ -260,6 +260,8 @@ static void __j1939_session_drop(struct j1939_session *session) > > static void j1939_session_destroy(struct j1939_session *session) > { > + struct sk_buff *skb; > + > if (session->transmission) { > if (session->err) > j1939_sk_errqueue(session, J1939_ERRQUEUE_TX_ABORT); > @@ -274,7 +276,11 @@ static void j1939_session_destroy(struct j1939_session *session) > WARN_ON_ONCE(!list_empty(&session->sk_session_queue_entry)); > WARN_ON_ONCE(!list_empty(&session->active_session_list_entry)); > > - skb_queue_purge(&session->skb_queue); > + while ((skb = skb_dequeue(&session->skb_queue)) != NULL) { > + /* drop ref taken in j1939_session_skb_queue() */ > + skb_unref(skb); > + kfree_skb(skb); > + } > __j1939_session_drop(session); > j1939_priv_put(session->priv); > kfree(session); > -- > 2.25.1 > > > -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
