Merge tag 'linux-can-fixes-for-5.13-20210616' of git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can

Marc Kleine-Budde says:

====================
pull-request: can 2021-06-16

this is a pull request of 4 patches for net/master.

The first patch is by Oleksij Rempel and fixes a Use-after-Free found
by syzbot in the j1939 stack.

The next patch is by Tetsuo Handa and fixes hung task detected by
syzbot in the bcm, raw and isotp protocols.

Norbert Slusarek's patch fixes a infoleak in bcm's struct
bcm_msg_head.

Pavel Skripkin's patch fixes a memory leak in the mcba_usb driver.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 185 insertions, 54 deletions

diff --git a/net/can/bcm.c b/net/can/bcm.c
index 909b9e684e04..f3e4d9528fa3 100644
--- a/net/can/bcm.c
+++ b/net/can/bcm.c
@@ -125,7 +125,7 @@ struct bcm_sock {
 	struct sock sk;
 	int bound;
 	int ifindex;
-	struct notifier_block notifier;
+	struct list_head notifier;
 	struct list_head rx_ops;
 	struct list_head tx_ops;
 	unsigned long dropped_usr_msgs;
@@ -133,6 +133,10 @@ struct bcm_sock {
 	char procname [32]; /* inode number in decimal with \0 */
 };
 
+static LIST_HEAD(bcm_notifier_list);
+static DEFINE_SPINLOCK(bcm_notifier_lock);
+static struct bcm_sock *bcm_busy_notifier;
+
 static inline struct bcm_sock *bcm_sk(const struct sock *sk)
 {
 	return (struct bcm_sock *)sk;
@@ -402,6 +406,7 @@ static enum hrtimer_restart bcm_tx_timeout_handler(struct hrtimer *hrtimer)
 		if (!op->count && (op->flags & TX_COUNTEVT)) {
 
 			/* create notification to user */
+			memset(&msg_head, 0, sizeof(msg_head));
 			msg_head.opcode  = TX_EXPIRED;
 			msg_head.flags   = op->flags;
 			msg_head.count   = op->count;
@@ -439,6 +444,7 @@ static void bcm_rx_changed(struct bcm_op *op, struct canfd_frame *data)
 	/* this element is not throttled anymore */
 	data->flags &= (BCM_CAN_FLAGS_MASK|RX_RECV);
 
+	memset(&head, 0, sizeof(head));
 	head.opcode  = RX_CHANGED;
 	head.flags   = op->flags;
 	head.count   = op->count;
@@ -560,6 +566,7 @@ static enum hrtimer_restart bcm_rx_timeout_handler(struct hrtimer *hrtimer)
 	}
 
 	/* create notification to user */
+	memset(&msg_head, 0, sizeof(msg_head));
 	msg_head.opcode  = RX_TIMEOUT;
 	msg_head.flags   = op->flags;
 	msg_head.count   = op->count;
@@ -1378,20 +1385,15 @@ static int bcm_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
 /*
  * notification handler for netdevice status changes
  */
-static int bcm_notifier(struct notifier_block *nb, unsigned long msg,
-			void *ptr)
+static void bcm_notify(struct bcm_sock *bo, unsigned long msg,
+		       struct net_device *dev)
 {
-	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
-	struct bcm_sock *bo = container_of(nb, struct bcm_sock, notifier);
 	struct sock *sk = &bo->sk;
 	struct bcm_op *op;
 	int notify_enodev = 0;
 
 	if (!net_eq(dev_net(dev), sock_net(sk)))
-		return NOTIFY_DONE;
-
-	if (dev->type != ARPHRD_CAN)
-		return NOTIFY_DONE;
+		return;
 
 	switch (msg) {
 
@@ -1426,7 +1428,28 @@ static int bcm_notifier(struct notifier_block *nb, unsigned long msg,
 				sk->sk_error_report(sk);
 		}
 	}
+}
 
+static int bcm_notifier(struct notifier_block *nb, unsigned long msg,
+			void *ptr)
+{
+	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+
+	if (dev->type != ARPHRD_CAN)
+		return NOTIFY_DONE;
+	if (msg != NETDEV_UNREGISTER && msg != NETDEV_DOWN)
+		return NOTIFY_DONE;
+	if (unlikely(bcm_busy_notifier)) /* Check for reentrant bug. */
+		return NOTIFY_DONE;
+
+	spin_lock(&bcm_notifier_lock);
+	list_for_each_entry(bcm_busy_notifier, &bcm_notifier_list, notifier) {
+		spin_unlock(&bcm_notifier_lock);
+		bcm_notify(bcm_busy_notifier, msg, dev);
+		spin_lock(&bcm_notifier_lock);
+	}
+	bcm_busy_notifier = NULL;
+	spin_unlock(&bcm_notifier_lock);
 	return NOTIFY_DONE;
 }
 
@@ -1446,9 +1469,9 @@ static int bcm_init(struct sock *sk)
 	INIT_LIST_HEAD(&bo->rx_ops);
 
 	/* set notifier */
-	bo->notifier.notifier_call = bcm_notifier;
-
-	register_netdevice_notifier(&bo->notifier);
+	spin_lock(&bcm_notifier_lock);
+	list_add_tail(&bo->notifier, &bcm_notifier_list);
+	spin_unlock(&bcm_notifier_lock);
 
 	return 0;
 }
@@ -1471,7 +1494,14 @@ static int bcm_release(struct socket *sock)
 
 	/* remove bcm_ops, timer, rx_unregister(), etc. */
 
-	unregister_netdevice_notifier(&bo->notifier);
+	spin_lock(&bcm_notifier_lock);
+	while (bcm_busy_notifier == bo) {
+		spin_unlock(&bcm_notifier_lock);
+		schedule_timeout_uninterruptible(1);
+		spin_lock(&bcm_notifier_lock);
+	}
+	list_del(&bo->notifier);
+	spin_unlock(&bcm_notifier_lock);
 
 	lock_sock(sk);
 
@@ -1692,6 +1722,10 @@ static struct pernet_operations canbcm_pernet_ops __read_mostly = {
 	.exit = canbcm_pernet_exit,
 };
 
+static struct notifier_block canbcm_notifier = {
+	.notifier_call = bcm_notifier
+};
+
 static int __init bcm_module_init(void)
 {
 	int err;
@@ -1705,12 +1739,14 @@ static int __init bcm_module_init(void)
 	}
 
 	register_pernet_subsys(&canbcm_pernet_ops);
+	register_netdevice_notifier(&canbcm_notifier);
 	return 0;
 }
 
 static void __exit bcm_module_exit(void)
 {
 	can_proto_unregister(&bcm_can_proto);
+	unregister_netdevice_notifier(&canbcm_notifier);
 	unregister_pernet_subsys(&canbcm_pernet_ops);
 }
 
diff --git a/net/can/isotp.c b/net/can/isotp.c
index 253b24417c8e..be6183f8ca11 100644
--- a/net/can/isotp.c
+++ b/net/can/isotp.c
@@ -143,10 +143,14 @@ struct isotp_sock {
 	u32 force_tx_stmin;
 	u32 force_rx_stmin;
 	struct tpcon rx, tx;
-	struct notifier_block notifier;
+	struct list_head notifier;
 	wait_queue_head_t wait;
 };
 
+static LIST_HEAD(isotp_notifier_list);
+static DEFINE_SPINLOCK(isotp_notifier_lock);
+static struct isotp_sock *isotp_busy_notifier;
+
 static inline struct isotp_sock *isotp_sk(const struct sock *sk)
 {
 	return (struct isotp_sock *)sk;
@@ -1013,7 +1017,14 @@ static int isotp_release(struct socket *sock)
 	/* wait for complete transmission of current pdu */
 	wait_event_interruptible(so->wait, so->tx.state == ISOTP_IDLE);
 
-	unregister_netdevice_notifier(&so->notifier);
+	spin_lock(&isotp_notifier_lock);
+	while (isotp_busy_notifier == so) {
+		spin_unlock(&isotp_notifier_lock);
+		schedule_timeout_uninterruptible(1);
+		spin_lock(&isotp_notifier_lock);
+	}
+	list_del(&so->notifier);
+	spin_unlock(&isotp_notifier_lock);
 
 	lock_sock(sk);
 
@@ -1317,21 +1328,16 @@ static int isotp_getsockopt(struct socket *sock, int level, int optname,
 	return 0;
 }
 
-static int isotp_notifier(struct notifier_block *nb, unsigned long msg,
-			  void *ptr)
+static void isotp_notify(struct isotp_sock *so, unsigned long msg,
+			 struct net_device *dev)
 {
-	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
-	struct isotp_sock *so = container_of(nb, struct isotp_sock, notifier);
 	struct sock *sk = &so->sk;
 
 	if (!net_eq(dev_net(dev), sock_net(sk)))
-		return NOTIFY_DONE;
-
-	if (dev->type != ARPHRD_CAN)
-		return NOTIFY_DONE;
+		return;
 
 	if (so->ifindex != dev->ifindex)
-		return NOTIFY_DONE;
+		return;
 
 	switch (msg) {
 	case NETDEV_UNREGISTER:
@@ -1357,7 +1363,28 @@ static int isotp_notifier(struct notifier_block *nb, unsigned long msg,
 			sk->sk_error_report(sk);
 		break;
 	}
+}
 
+static int isotp_notifier(struct notifier_block *nb, unsigned long msg,
+			  void *ptr)
+{
+	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+
+	if (dev->type != ARPHRD_CAN)
+		return NOTIFY_DONE;
+	if (msg != NETDEV_UNREGISTER && msg != NETDEV_DOWN)
+		return NOTIFY_DONE;
+	if (unlikely(isotp_busy_notifier)) /* Check for reentrant bug. */
+		return NOTIFY_DONE;
+
+	spin_lock(&isotp_notifier_lock);
+	list_for_each_entry(isotp_busy_notifier, &isotp_notifier_list, notifier) {
+		spin_unlock(&isotp_notifier_lock);
+		isotp_notify(isotp_busy_notifier, msg, dev);
+		spin_lock(&isotp_notifier_lock);
+	}
+	isotp_busy_notifier = NULL;
+	spin_unlock(&isotp_notifier_lock);
 	return NOTIFY_DONE;
 }
 
@@ -1394,8 +1421,9 @@ static int isotp_init(struct sock *sk)
 
 	init_waitqueue_head(&so->wait);
 
-	so->notifier.notifier_call = isotp_notifier;
-	register_netdevice_notifier(&so->notifier);
+	spin_lock(&isotp_notifier_lock);
+	list_add_tail(&so->notifier, &isotp_notifier_list);
+	spin_unlock(&isotp_notifier_lock);
 
 	return 0;
 }
@@ -1442,6 +1470,10 @@ static const struct can_proto isotp_can_proto = {
 	.prot = &isotp_proto,
 };
 
+static struct notifier_block canisotp_notifier = {
+	.notifier_call = isotp_notifier
+};
+
 static __init int isotp_module_init(void)
 {
 	int err;
@@ -1451,6 +1483,8 @@ static __init int isotp_module_init(void)
 	err = can_proto_register(&isotp_can_proto);
 	if (err < 0)
 		pr_err("can: registration of isotp protocol failed\n");
+	else
+		register_netdevice_notifier(&canisotp_notifier);
 
 	return err;
 }
@@ -1458,6 +1492,7 @@ static __init int isotp_module_init(void)
 static __exit void isotp_module_exit(void)
 {
 	can_proto_unregister(&isotp_can_proto);
+	unregister_netdevice_notifier(&canisotp_notifier);
 }
 
 module_init(isotp_module_init);
diff --git a/net/can/j1939/transport.c b/net/can/j1939/transport.c
index e09d087ba240..c3946c355882 100644
--- a/net/can/j1939/transport.c
+++ b/net/can/j1939/transport.c
@@ -330,6 +330,9 @@ static void j1939_session_skb_drop_old(struct j1939_session *session)
 
 	if ((do_skcb->offset + do_skb->len) < offset_start) {
 		__skb_unlink(do_skb, &session->skb_queue);
+		/* drop ref taken in j1939_session_skb_queue() */
+		skb_unref(do_skb);
+
 		kfree_skb(do_skb);
 	}
 	spin_unlock_irqrestore(&session->skb_queue.lock, flags);
@@ -349,12 +352,13 @@ void j1939_session_skb_queue(struct j1939_session *session,
 
 	skcb->flags |= J1939_ECU_LOCAL_SRC;
 
+	skb_get(skb);
 	skb_queue_tail(&session->skb_queue, skb);
 }
 
 static struct
-sk_buff *j1939_session_skb_find_by_offset(struct j1939_session *session,
-					  unsigned int offset_start)
+sk_buff *j1939_session_skb_get_by_offset(struct j1939_session *session,
+					 unsigned int offset_start)
 {
 	struct j1939_priv *priv = session->priv;
 	struct j1939_sk_buff_cb *do_skcb;
@@ -371,6 +375,10 @@ sk_buff *j1939_session_skb_find_by_offset(struct j1939_session *session,
 			skb = do_skb;
 		}
 	}
+
+	if (skb)
+		skb_get(skb);
+
 	spin_unlock_irqrestore(&session->skb_queue.lock, flags);
 
 	if (!skb)
@@ -381,12 +389,12 @@ sk_buff *j1939_session_skb_find_by_offset(struct j1939_session *session,
 	return skb;
 }
 
-static struct sk_buff *j1939_session_skb_find(struct j1939_session *session)
+static struct sk_buff *j1939_session_skb_get(struct j1939_session *session)
 {
 	unsigned int offset_start;
 
 	offset_start = session->pkt.dpo * 7;
-	return j1939_session_skb_find_by_offset(session, offset_start);
+	return j1939_session_skb_get_by_offset(session, offset_start);
 }
 
 /* see if we are receiver
@@ -776,7 +784,7 @@ static int j1939_session_tx_dat(struct j1939_session *session)
 	int ret = 0;
 	u8 dat[8];
 
-	se_skb = j1939_session_skb_find_by_offset(session, session->pkt.tx * 7);
+	se_skb = j1939_session_skb_get_by_offset(session, session->pkt.tx * 7);
 	if (!se_skb)
 		return -ENOBUFS;
 
@@ -801,7 +809,8 @@ static int j1939_session_tx_dat(struct j1939_session *session)
 			netdev_err_once(priv->ndev,
 					"%s: 0x%p: requested data outside of queued buffer: offset %i, len %i, pkt.tx: %i\n",
 					__func__, session, skcb->offset, se_skb->len , session->pkt.tx);
-			return -EOVERFLOW;
+			ret = -EOVERFLOW;
+			goto out_free;
 		}
 
 		if (!len) {
@@ -835,6 +844,12 @@ static int j1939_session_tx_dat(struct j1939_session *session)
 	if (pkt_done)
 		j1939_tp_set_rxtimeout(session, 250);
 
+ out_free:
+	if (ret)
+		kfree_skb(se_skb);
+	else
+		consume_skb(se_skb);
+
 	return ret;
 }
 
@@ -1007,7 +1022,7 @@ static int j1939_xtp_txnext_receiver(struct j1939_session *session)
 static int j1939_simple_txnext(struct j1939_session *session)
 {
 	struct j1939_priv *priv = session->priv;
-	struct sk_buff *se_skb = j1939_session_skb_find(session);
+	struct sk_buff *se_skb = j1939_session_skb_get(session);
 	struct sk_buff *skb;
 	int ret;
 
@@ -1015,8 +1030,10 @@ static int j1939_simple_txnext(struct j1939_session *session)
 		return 0;
 
 	skb = skb_clone(se_skb, GFP_ATOMIC);
-	if (!skb)
-		return -ENOMEM;
+	if (!skb) {
+		ret = -ENOMEM;
+		goto out_free;
+	}
 
 	can_skb_set_owner(skb, se_skb->sk);
 
@@ -1024,12 +1041,18 @@ static int j1939_simple_txnext(struct j1939_session *session)
 
 	ret = j1939_send_one(priv, skb);
 	if (ret)
-		return ret;
+		goto out_free;
 
 	j1939_sk_errqueue(session, J1939_ERRQUEUE_SCHED);
 	j1939_sk_queue_activate_next(session);
 
-	return 0;
+ out_free:
+	if (ret)
+		kfree_skb(se_skb);
+	else
+		consume_skb(se_skb);
+
+	return ret;
 }
 
 static bool j1939_session_deactivate_locked(struct j1939_session *session)
@@ -1170,9 +1193,10 @@ static void j1939_session_completed(struct j1939_session *session)
 	struct sk_buff *skb;
 
 	if (!session->transmission) {
-		skb = j1939_session_skb_find(session);
+		skb = j1939_session_skb_get(session);
 		/* distribute among j1939 receivers */
 		j1939_sk_recv(session->priv, skb);
+		consume_skb(skb);
 	}
 
 	j1939_session_deactivate_activate_next(session);
@@ -1744,7 +1768,7 @@ static void j1939_xtp_rx_dat_one(struct j1939_session *session,
 {
 	struct j1939_priv *priv = session->priv;
 	struct j1939_sk_buff_cb *skcb;
-	struct sk_buff *se_skb;
+	struct sk_buff *se_skb = NULL;
 	const u8 *dat;
 	u8 *tpdat;
 	int offset;
@@ -1786,7 +1810,7 @@ static void j1939_xtp_rx_dat_one(struct j1939_session *session,
 		goto out_session_cancel;
 	}
 
-	se_skb = j1939_session_skb_find_by_offset(session, packet * 7);
+	se_skb = j1939_session_skb_get_by_offset(session, packet * 7);
 	if (!se_skb) {
 		netdev_warn(priv->ndev, "%s: 0x%p: no skb found\n", __func__,
 			    session);
@@ -1848,11 +1872,13 @@ static void j1939_xtp_rx_dat_one(struct j1939_session *session,
 		j1939_tp_set_rxtimeout(session, 250);
 	}
 	session->last_cmd = 0xff;
+	consume_skb(se_skb);
 	j1939_session_put(session);
 
 	return;
 
  out_session_cancel:
+	kfree_skb(se_skb);
 	j1939_session_timers_cancel(session);
 	j1939_session_cancel(session, J1939_XTP_ABORT_FAULT);
 	j1939_session_put(session);
diff --git a/net/can/raw.c b/net/can/raw.c
index 139d9471ddcf..ac96fc210025 100644
--- a/net/can/raw.c
+++ b/net/can/raw.c
@@ -83,7 +83,7 @@ struct raw_sock {
 	struct sock sk;
 	int bound;
 	int ifindex;
-	struct notifier_block notifier;
+	struct list_head notifier;
 	int loopback;
 	int recv_own_msgs;
 	int fd_frames;
@@ -95,6 +95,10 @@ struct raw_sock {
 	struct uniqframe __percpu *uniq;
 };
 
+static LIST_HEAD(raw_notifier_list);
+static DEFINE_SPINLOCK(raw_notifier_lock);
+static struct raw_sock *raw_busy_notifier;
+
 /* Return pointer to store the extra msg flags for raw_recvmsg().
  * We use the space of one unsigned int beyond the 'struct sockaddr_can'
  * in skb->cb.
@@ -263,21 +267,16 @@ static int raw_enable_allfilters(struct net *net, struct net_device *dev,
 	return err;
 }
 
-static int raw_notifier(struct notifier_block *nb,
-			unsigned long msg, void *ptr)
+static void raw_notify(struct raw_sock *ro, unsigned long msg,
+		       struct net_device *dev)
 {
-	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
-	struct raw_sock *ro = container_of(nb, struct raw_sock, notifier);
 	struct sock *sk = &ro->sk;
 
 	if (!net_eq(dev_net(dev), sock_net(sk)))
-		return NOTIFY_DONE;
-
-	if (dev->type != ARPHRD_CAN)
-		return NOTIFY_DONE;
+		return;
 
 	if (ro->ifindex != dev->ifindex)
-		return NOTIFY_DONE;
+		return;
 
 	switch (msg) {
 	case NETDEV_UNREGISTER:
@@ -305,7 +304,28 @@ static int raw_notifier(struct notifier_block *nb,
 			sk->sk_error_report(sk);
 		break;
 	}
+}
+
+static int raw_notifier(struct notifier_block *nb, unsigned long msg,
+			void *ptr)
+{
+	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+
+	if (dev->type != ARPHRD_CAN)
+		return NOTIFY_DONE;
+	if (msg != NETDEV_UNREGISTER && msg != NETDEV_DOWN)
+		return NOTIFY_DONE;
+	if (unlikely(raw_busy_notifier)) /* Check for reentrant bug. */
+		return NOTIFY_DONE;
 
+	spin_lock(&raw_notifier_lock);
+	list_for_each_entry(raw_busy_notifier, &raw_notifier_list, notifier) {
+		spin_unlock(&raw_notifier_lock);
+		raw_notify(raw_busy_notifier, msg, dev);
+		spin_lock(&raw_notifier_lock);
+	}
+	raw_busy_notifier = NULL;
+	spin_unlock(&raw_notifier_lock);
 	return NOTIFY_DONE;
 }
 
@@ -334,9 +354,9 @@ static int raw_init(struct sock *sk)
 		return -ENOMEM;
 
 	/* set notifier */
-	ro->notifier.notifier_call = raw_notifier;
-
-	register_netdevice_notifier(&ro->notifier);
+	spin_lock(&raw_notifier_lock);
+	list_add_tail(&ro->notifier, &raw_notifier_list);
+	spin_unlock(&raw_notifier_lock);
 
 	return 0;
 }
@@ -351,7 +371,14 @@ static int raw_release(struct socket *sock)
 
 	ro = raw_sk(sk);
 
-	unregister_netdevice_notifier(&ro->notifier);
+	spin_lock(&raw_notifier_lock);
+	while (raw_busy_notifier == ro) {
+		spin_unlock(&raw_notifier_lock);
+		schedule_timeout_uninterruptible(1);
+		spin_lock(&raw_notifier_lock);
+	}
+	list_del(&ro->notifier);
+	spin_unlock(&raw_notifier_lock);
 
 	lock_sock(sk);
 
@@ -889,6 +916,10 @@ static const struct can_proto raw_can_proto = {
 	.prot       = &raw_proto,
 };
 
+static struct notifier_block canraw_notifier = {
+	.notifier_call = raw_notifier
+};
+
 static __init int raw_module_init(void)
 {
 	int err;
@@ -898,6 +929,8 @@ static __init int raw_module_init(void)
 	err = can_proto_register(&raw_can_proto);
 	if (err < 0)
 		pr_err("can: registration of raw protocol failed\n");
+	else
+		register_netdevice_notifier(&canraw_notifier);
 
 	return err;
 }
@@ -905,6 +938,7 @@ static __init int raw_module_init(void)
 static __exit void raw_module_exit(void)
 {
 	can_proto_unregister(&raw_can_proto);
+	unregister_netdevice_notifier(&canraw_notifier);
 }
 
 module_init(raw_module_init);