1 files changed, 158 insertions, 98 deletions

diff --git a/net/can/isotp.c b/net/can/isotp.c
index 608f8c24ae46..ce588b85665a 100644
--- a/net/can/isotp.c
+++ b/net/can/isotp.c
@@ -72,7 +72,7 @@
 #include <net/sock.h>
 #include <net/net_namespace.h>
 
-MODULE_DESCRIPTION("PF_CAN isotp 15765-2:2016 protocol");
+MODULE_DESCRIPTION("PF_CAN ISO 15765-2 transport protocol");
 MODULE_LICENSE("Dual BSD/GPL");
 MODULE_AUTHOR("Oliver Hartkopp <socketcan@hartkopp.net>");
 MODULE_ALIAS("can-proto-6");
@@ -83,12 +83,24 @@ MODULE_ALIAS("can-proto-6");
 			 (CAN_EFF_MASK | CAN_EFF_FLAG | CAN_RTR_FLAG) : \
 			 (CAN_SFF_MASK | CAN_EFF_FLAG | CAN_RTR_FLAG))
 
-/* ISO 15765-2:2016 supports more than 4095 byte per ISO PDU as the FF_DL can
- * take full 32 bit values (4 Gbyte). We would need some good concept to handle
- * this between user space and kernel space. For now increase the static buffer
- * to something about 64 kbyte to be able to test this new functionality.
+/* Since ISO 15765-2:2016 the CAN isotp protocol supports more than 4095
+ * byte per ISO PDU as the FF_DL can take full 32 bit values (4 Gbyte).
+ * We would need some good concept to handle this between user space and
+ * kernel space. For now set the static buffer to something about 8 kbyte
+ * to be able to test this new functionality.
  */
-#define MAX_MSG_LENGTH 66000
+#define DEFAULT_MAX_PDU_SIZE 8300
+
+/* maximum PDU size before ISO 15765-2:2016 extension was 4095 */
+#define MAX_12BIT_PDU_SIZE 4095
+
+/* limit the isotp pdu size from the optional module parameter to 1MByte */
+#define MAX_PDU_SIZE (1025 * 1024U)
+
+static unsigned int max_pdu_size __read_mostly = DEFAULT_MAX_PDU_SIZE;
+module_param(max_pdu_size, uint, 0444);
+MODULE_PARM_DESC(max_pdu_size, "maximum isotp pdu size (default "
+		 __stringify(DEFAULT_MAX_PDU_SIZE) ")");
 
 /* N_PCI type values in bits 7-4 of N_PCI bytes */
 #define N_PCI_SF 0x00	/* single frame */
@@ -119,17 +131,20 @@ enum {
 	ISOTP_WAIT_FIRST_FC,
 	ISOTP_WAIT_FC,
 	ISOTP_WAIT_DATA,
-	ISOTP_SENDING
+	ISOTP_SENDING,
+	ISOTP_SHUTDOWN,
 };
 
 struct tpcon {
-	unsigned int idx;
+	u8 *buf;
+	unsigned int buflen;
 	unsigned int len;
+	unsigned int idx;
 	u32 state;
 	u8 bs;
 	u8 sn;
 	u8 ll_dl;
-	u8 buf[MAX_MSG_LENGTH + 1];
+	u8 sbuf[DEFAULT_MAX_PDU_SIZE];
 };
 
 struct isotp_sock {
@@ -140,7 +155,7 @@ struct isotp_sock {
 	canid_t rxid;
 	ktime_t tx_gap;
 	ktime_t lastrxcf_tstamp;
-	struct hrtimer rxtimer, txtimer;
+	struct hrtimer rxtimer, txtimer, txfrtimer;
 	struct can_isotp_options opt;
 	struct can_isotp_fc_options rxfc, txfc;
 	struct can_isotp_ll_options ll;
@@ -174,12 +189,6 @@ static bool isotp_register_rxid(struct isotp_sock *so)
 	return (isotp_bc_flags(so) == 0);
 }
 
-static bool isotp_register_txecho(struct isotp_sock *so)
-{
-	/* all modes but SF_BROADCAST register for tx echo skbs */
-	return (isotp_bc_flags(so) != CAN_ISOTP_SF_BROADCAST);
-}
-
 static enum hrtimer_restart isotp_rx_timer_handler(struct hrtimer *hrtimer)
 {
 	struct isotp_sock *so = container_of(hrtimer, struct isotp_sock,
@@ -269,6 +278,7 @@ static int isotp_send_fc(struct sock *sk, int ae, u8 flowstatus)
 static void isotp_rcv_skb(struct sk_buff *skb, struct sock *sk)
 {
 	struct sockaddr_can *addr = (struct sockaddr_can *)skb->cb;
+	enum skb_drop_reason reason;
 
 	BUILD_BUG_ON(sizeof(skb->cb) < sizeof(struct sockaddr_can));
 
@@ -276,8 +286,8 @@ static void isotp_rcv_skb(struct sk_buff *skb, struct sock *sk)
 	addr->can_family = AF_CAN;
 	addr->can_ifindex = skb->dev->ifindex;
 
-	if (sock_queue_rcv_skb(sk, skb) < 0)
-		kfree_skb(skb);
+	if (sock_queue_rcv_skb_reason(sk, skb, &reason) < 0)
+		sk_skb_reason_drop(sk, skb, reason);
 }
 
 static u8 padlen(u8 datalen)
@@ -373,8 +383,9 @@ static int isotp_rcv_fc(struct isotp_sock *so, struct canfd_frame *cf, int ae)
 		return 1;
 	}
 
-	/* get communication parameters only from the first FC frame */
-	if (so->tx.state == ISOTP_WAIT_FIRST_FC) {
+	/* get static/dynamic communication params from first/every FC frame */
+	if (so->tx.state == ISOTP_WAIT_FIRST_FC ||
+	    so->opt.flags & CAN_ISOTP_DYN_FC_PARMS) {
 		so->txfc.bs = cf->data[ae + 1];
 		so->txfc.stmin = cf->data[ae + 2];
 
@@ -503,7 +514,17 @@ static int isotp_rcv_ff(struct sock *sk, struct canfd_frame *cf, int ae)
 	if (so->rx.len + ae + off + ff_pci_sz < so->rx.ll_dl)
 		return 1;
 
-	if (so->rx.len > MAX_MSG_LENGTH) {
+	/* PDU size > default => try max_pdu_size */
+	if (so->rx.len > so->rx.buflen && so->rx.buflen < max_pdu_size) {
+		u8 *newbuf = kmalloc(max_pdu_size, GFP_ATOMIC);
+
+		if (newbuf) {
+			so->rx.buf = newbuf;
+			so->rx.buflen = max_pdu_size;
+		}
+	}
+
+	if (so->rx.len > so->rx.buflen) {
 		/* send FC frame with overflow status */
 		isotp_send_fc(sk, ae, ISOTP_FC_OVFLW);
 		return 1;
@@ -807,7 +828,7 @@ static void isotp_create_fframe(struct canfd_frame *cf, struct isotp_sock *so,
 		cf->data[0] = so->opt.ext_address;
 
 	/* create N_PCI bytes with 12/32 bit FF_DL data length */
-	if (so->tx.len > 4095) {
+	if (so->tx.len > MAX_12BIT_PDU_SIZE) {
 		/* use 32 bit FF_DL notation */
 		cf->data[ae] = N_PCI_FF;
 		cf->data[ae + 1] = 0;
@@ -871,7 +892,7 @@ static void isotp_rcv_echo(struct sk_buff *skb, void *data)
 	}
 
 	/* start timer to send next consecutive frame with correct delay */
-	hrtimer_start(&so->txtimer, so->tx_gap, HRTIMER_MODE_REL_SOFT);
+	hrtimer_start(&so->txfrtimer, so->tx_gap, HRTIMER_MODE_REL_SOFT);
 }
 
 static enum hrtimer_restart isotp_tx_timer_handler(struct hrtimer *hrtimer)
@@ -879,56 +900,45 @@ static enum hrtimer_restart isotp_tx_timer_handler(struct hrtimer *hrtimer)
 	struct isotp_sock *so = container_of(hrtimer, struct isotp_sock,
 					     txtimer);
 	struct sock *sk = &so->sk;
-	enum hrtimer_restart restart = HRTIMER_NORESTART;
-
-	switch (so->tx.state) {
-	case ISOTP_SENDING:
 
-		/* cfecho should be consumed by isotp_rcv_echo() here */
-		if (!so->cfecho) {
-			/* start timeout for unlikely lost echo skb */
-			hrtimer_set_expires(&so->txtimer,
-					    ktime_add(ktime_get(),
-						      ktime_set(ISOTP_ECHO_TIMEOUT, 0)));
-			restart = HRTIMER_RESTART;
+	/* don't handle timeouts in IDLE or SHUTDOWN state */
+	if (so->tx.state == ISOTP_IDLE || so->tx.state == ISOTP_SHUTDOWN)
+		return HRTIMER_NORESTART;
 
-			/* push out the next consecutive frame */
-			isotp_send_cframe(so);
-			break;
-		}
+	/* we did not get any flow control or echo frame in time */
 
-		/* cfecho has not been cleared in isotp_rcv_echo() */
-		pr_notice_once("can-isotp: cfecho %08X timeout\n", so->cfecho);
-		fallthrough;
+	/* report 'communication error on send' */
+	sk->sk_err = ECOMM;
+	if (!sock_flag(sk, SOCK_DEAD))
+		sk_error_report(sk);
 
-	case ISOTP_WAIT_FC:
-	case ISOTP_WAIT_FIRST_FC:
+	/* reset tx state */
+	so->tx.state = ISOTP_IDLE;
+	wake_up_interruptible(&so->wait);
 
-		/* we did not get any flow control frame in time */
+	return HRTIMER_NORESTART;
+}
 
-		/* report 'communication error on send' */
-		sk->sk_err = ECOMM;
-		if (!sock_flag(sk, SOCK_DEAD))
-			sk_error_report(sk);
+static enum hrtimer_restart isotp_txfr_timer_handler(struct hrtimer *hrtimer)
+{
+	struct isotp_sock *so = container_of(hrtimer, struct isotp_sock,
+					     txfrtimer);
 
-		/* reset tx state */
-		so->tx.state = ISOTP_IDLE;
-		wake_up_interruptible(&so->wait);
-		break;
+	/* start echo timeout handling and cover below protocol error */
+	hrtimer_start(&so->txtimer, ktime_set(ISOTP_ECHO_TIMEOUT, 0),
+		      HRTIMER_MODE_REL_SOFT);
 
-	default:
-		WARN_ONCE(1, "can-isotp: tx timer state %08X cfecho %08X\n",
-			  so->tx.state, so->cfecho);
-	}
+	/* cfecho should be consumed by isotp_rcv_echo() here */
+	if (so->tx.state == ISOTP_SENDING && !so->cfecho)
+		isotp_send_cframe(so);
 
-	return restart;
+	return HRTIMER_NORESTART;
 }
 
 static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
 {
 	struct sock *sk = sock->sk;
 	struct isotp_sock *so = isotp_sk(sk);
-	u32 old_state = so->tx.state;
 	struct sk_buff *skb;
 	struct net_device *dev;
 	struct canfd_frame *cf;
@@ -938,26 +948,34 @@ static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
 	int off;
 	int err;
 
-	if (!so->bound)
+	if (!so->bound || so->tx.state == ISOTP_SHUTDOWN)
 		return -EADDRNOTAVAIL;
 
-	/* we do not support multiple buffers - for now */
-	if (cmpxchg(&so->tx.state, ISOTP_IDLE, ISOTP_SENDING) != ISOTP_IDLE ||
-	    wq_has_sleeper(&so->wait)) {
-		if (msg->msg_flags & MSG_DONTWAIT) {
-			err = -EAGAIN;
-			goto err_out;
-		}
+	while (cmpxchg(&so->tx.state, ISOTP_IDLE, ISOTP_SENDING) != ISOTP_IDLE) {
+		/* we do not support multiple buffers - for now */
+		if (msg->msg_flags & MSG_DONTWAIT)
+			return -EAGAIN;
+
+		if (so->tx.state == ISOTP_SHUTDOWN)
+			return -EADDRNOTAVAIL;
 
 		/* wait for complete transmission of current pdu */
 		err = wait_event_interruptible(so->wait, so->tx.state == ISOTP_IDLE);
 		if (err)
-			goto err_out;
+			goto err_event_drop;
+	}
 
-		so->tx.state = ISOTP_SENDING;
+	/* PDU size > default => try max_pdu_size */
+	if (size > so->tx.buflen && so->tx.buflen < max_pdu_size) {
+		u8 *newbuf = kmalloc(max_pdu_size, GFP_KERNEL);
+
+		if (newbuf) {
+			so->tx.buf = newbuf;
+			so->tx.buflen = max_pdu_size;
+		}
 	}
 
-	if (!size || size > MAX_MSG_LENGTH) {
+	if (!size || size > so->tx.buflen) {
 		err = -EINVAL;
 		goto err_out_drop;
 	}
@@ -1084,21 +1102,26 @@ static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
 
 	if (wait_tx_done) {
 		/* wait for complete transmission of current pdu */
-		wait_event_interruptible(so->wait, so->tx.state == ISOTP_IDLE);
+		err = wait_event_interruptible(so->wait, so->tx.state == ISOTP_IDLE);
+		if (err)
+			goto err_event_drop;
 
-		if (sk->sk_err)
-			return -sk->sk_err;
+		err = sock_error(sk);
+		if (err)
+			return err;
 	}
 
 	return size;
 
+err_event_drop:
+	/* got signal: force tx state machine to be idle */
+	so->tx.state = ISOTP_IDLE;
+	hrtimer_cancel(&so->txfrtimer);
+	hrtimer_cancel(&so->txtimer);
 err_out_drop:
 	/* drop this PDU and unlock a potential wait queue */
-	old_state = ISOTP_IDLE;
-err_out:
-	so->tx.state = old_state;
-	if (so->tx.state == ISOTP_IDLE)
-		wake_up_interruptible(&so->wait);
+	so->tx.state = ISOTP_IDLE;
+	wake_up_interruptible(&so->wait);
 
 	return err;
 }
@@ -1111,7 +1134,7 @@ static int isotp_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
 	struct isotp_sock *so = isotp_sk(sk);
 	int ret = 0;
 
-	if (flags & ~(MSG_DONTWAIT | MSG_TRUNC | MSG_PEEK))
+	if (flags & ~(MSG_DONTWAIT | MSG_TRUNC | MSG_PEEK | MSG_CMSG_COMPAT))
 		return -EINVAL;
 
 	if (!so->bound)
@@ -1130,7 +1153,7 @@ static int isotp_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
 	if (ret < 0)
 		goto out_err;
 
-	sock_recv_timestamp(msg, sk, skb);
+	sock_recv_cmsgs(msg, sk, skb);
 
 	if (msg->msg_name) {
 		__sockaddr_check_size(ISOTP_MIN_NAMELEN);
@@ -1160,7 +1183,13 @@ static int isotp_release(struct socket *sock)
 	net = sock_net(sk);
 
 	/* wait for complete transmission of current pdu */
-	wait_event_interruptible(so->wait, so->tx.state == ISOTP_IDLE);
+	while (wait_event_interruptible(so->wait, so->tx.state == ISOTP_IDLE) == 0 &&
+	       cmpxchg(&so->tx.state, ISOTP_IDLE, ISOTP_SHUTDOWN) != ISOTP_IDLE)
+		;
+
+	/* force state machines to be idle also when a signal occurred */
+	so->tx.state = ISOTP_SHUTDOWN;
+	so->rx.state = ISOTP_IDLE;
 
 	spin_lock(&isotp_notifier_lock);
 	while (isotp_busy_notifier == so) {
@@ -1174,7 +1203,7 @@ static int isotp_release(struct socket *sock)
 	lock_sock(sk);
 
 	/* remove current filters & unregister */
-	if (so->bound && isotp_register_txecho(so)) {
+	if (so->bound) {
 		if (so->ifindex) {
 			struct net_device *dev;
 
@@ -1194,22 +1223,30 @@ static int isotp_release(struct socket *sock)
 		}
 	}
 
+	hrtimer_cancel(&so->txfrtimer);
 	hrtimer_cancel(&so->txtimer);
 	hrtimer_cancel(&so->rxtimer);
 
 	so->ifindex = 0;
 	so->bound = 0;
 
+	if (so->rx.buf != so->rx.sbuf)
+		kfree(so->rx.buf);
+
+	if (so->tx.buf != so->tx.sbuf)
+		kfree(so->tx.buf);
+
 	sock_orphan(sk);
 	sock->sk = NULL;
 
 	release_sock(sk);
+	sock_prot_inuse_add(net, sk->sk_prot, -1);
 	sock_put(sk);
 
 	return 0;
 }
 
-static int isotp_bind(struct socket *sock, struct sockaddr *uaddr, int len)
+static int isotp_bind(struct socket *sock, struct sockaddr_unsized *uaddr, int len)
 {
 	struct sockaddr_can *addr = (struct sockaddr_can *)uaddr;
 	struct sock *sk = sock->sk;
@@ -1225,6 +1262,9 @@ static int isotp_bind(struct socket *sock, struct sockaddr *uaddr, int len)
 	if (len < ISOTP_MIN_NAMELEN)
 		return -EINVAL;
 
+	if (addr->can_family != AF_CAN)
+		return -EINVAL;
+
 	/* sanitize tx CAN identifier */
 	if (tx_id & CAN_EFF_FLAG)
 		tx_id &= (CAN_EFF_FLAG | CAN_EFF_MASK);
@@ -1273,7 +1313,7 @@ static int isotp_bind(struct socket *sock, struct sockaddr *uaddr, int len)
 		err = -ENODEV;
 		goto out;
 	}
-	if (dev->mtu < so->ll.mtu) {
+	if (READ_ONCE(dev->mtu) < so->ll.mtu) {
 		dev_put(dev);
 		err = -EINVAL;
 		goto out;
@@ -1287,14 +1327,12 @@ static int isotp_bind(struct socket *sock, struct sockaddr *uaddr, int len)
 		can_rx_register(net, dev, rx_id, SINGLE_MASK(rx_id),
 				isotp_rcv, sk, "isotp", sk);
 
-	if (isotp_register_txecho(so)) {
-		/* no consecutive frame echo skb in flight */
-		so->cfecho = 0;
+	/* no consecutive frame echo skb in flight */
+	so->cfecho = 0;
 
-		/* register for echo skb's */
-		can_rx_register(net, dev, tx_id, SINGLE_MASK(tx_id),
-				isotp_rcv_echo, sk, "isotpe", sk);
-	}
+	/* register for echo skb's */
+	can_rx_register(net, dev, tx_id, SINGLE_MASK(tx_id),
+			isotp_rcv_echo, sk, "isotpe", sk);
 
 	dev_put(dev);
 
@@ -1515,7 +1553,7 @@ static void isotp_notify(struct isotp_sock *so, unsigned long msg,
 	case NETDEV_UNREGISTER:
 		lock_sock(sk);
 		/* remove current filters & unregister */
-		if (so->bound && isotp_register_txecho(so)) {
+		if (so->bound) {
 			if (isotp_register_rxid(so))
 				can_rx_unregister(dev_net(dev), dev, so->rxid,
 						  SINGLE_MASK(so->rxid),
@@ -1593,10 +1631,15 @@ static int isotp_init(struct sock *sk)
 	so->rx.state = ISOTP_IDLE;
 	so->tx.state = ISOTP_IDLE;
 
-	hrtimer_init(&so->rxtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_SOFT);
-	so->rxtimer.function = isotp_rx_timer_handler;
-	hrtimer_init(&so->txtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_SOFT);
-	so->txtimer.function = isotp_tx_timer_handler;
+	so->rx.buf = so->rx.sbuf;
+	so->tx.buf = so->tx.sbuf;
+	so->rx.buflen = ARRAY_SIZE(so->rx.sbuf);
+	so->tx.buflen = ARRAY_SIZE(so->tx.sbuf);
+
+	hrtimer_setup(&so->rxtimer, isotp_rx_timer_handler, CLOCK_MONOTONIC, HRTIMER_MODE_REL_SOFT);
+	hrtimer_setup(&so->txtimer, isotp_tx_timer_handler, CLOCK_MONOTONIC, HRTIMER_MODE_REL_SOFT);
+	hrtimer_setup(&so->txfrtimer, isotp_txfr_timer_handler, CLOCK_MONOTONIC,
+		      HRTIMER_MODE_REL_SOFT);
 
 	init_waitqueue_head(&so->wait);
 	spin_lock_init(&so->rx_lock);
@@ -1608,6 +1651,21 @@ static int isotp_init(struct sock *sk)
 	return 0;
 }
 
+static __poll_t isotp_poll(struct file *file, struct socket *sock, poll_table *wait)
+{
+	struct sock *sk = sock->sk;
+	struct isotp_sock *so = isotp_sk(sk);
+
+	__poll_t mask = datagram_poll(file, sock, wait);
+	poll_wait(file, &so->wait, wait);
+
+	/* Check for false positives due to TX state */
+	if ((mask & EPOLLWRNORM) && (so->tx.state != ISOTP_IDLE))
+		mask &= ~(EPOLLOUT | EPOLLWRNORM);
+
+	return mask;
+}
+
 static int isotp_sock_no_ioctlcmd(struct socket *sock, unsigned int cmd,
 				  unsigned long arg)
 {
@@ -1623,7 +1681,7 @@ static const struct proto_ops isotp_ops = {
 	.socketpair = sock_no_socketpair,
 	.accept = sock_no_accept,
 	.getname = isotp_getname,
-	.poll = datagram_poll,
+	.poll = isotp_poll,
 	.ioctl = isotp_sock_no_ioctlcmd,
 	.gettstamp = sock_gettstamp,
 	.listen = sock_no_listen,
@@ -1633,7 +1691,6 @@ static const struct proto_ops isotp_ops = {
 	.sendmsg = isotp_sendmsg,
 	.recvmsg = isotp_recvmsg,
 	.mmap = sock_no_mmap,
-	.sendpage = sock_no_sendpage,
 };
 
 static struct proto isotp_proto __read_mostly = {
@@ -1658,7 +1715,10 @@ static __init int isotp_module_init(void)
 {
 	int err;
 
-	pr_info("can: isotp protocol\n");
+	max_pdu_size = max_t(unsigned int, max_pdu_size, MAX_12BIT_PDU_SIZE);
+	max_pdu_size = min_t(unsigned int, max_pdu_size, MAX_PDU_SIZE);
+
+	pr_info("can: isotp protocol (max_pdu_size %d)\n", max_pdu_size);
 
 	err = can_proto_register(&isotp_can_proto);
 	if (err < 0)