summaryrefslogtreecommitdiff
path: root/net/can
diff options
context:
space:
mode:
Diffstat (limited to 'net/can')
-rw-r--r--net/can/bcm.c127
-rw-r--r--net/can/isotp.c298
2 files changed, 328 insertions, 97 deletions
diff --git a/net/can/bcm.c b/net/can/bcm.c
index 756acfd20c6c..a40519638a26 100644
--- a/net/can/bcm.c
+++ b/net/can/bcm.c
@@ -58,6 +58,7 @@
#include <linux/can/skb.h>
#include <linux/can/bcm.h>
#include <linux/slab.h>
+#include <linux/workqueue.h>
#include <linux/spinlock.h>
#include <net/sock.h>
#include <net/net_namespace.h>
@@ -91,6 +92,8 @@ MODULE_ALIAS("can-proto-2");
#define BCM_MIN_NAMELEN CAN_REQUIRED_SIZE(struct sockaddr_can, can_ifindex)
+static struct workqueue_struct *bcm_wq;
+
/*
* easy access to the first 64 bit of can(fd)_frame payload. cp->data is
* 64 bit aligned so the offset has to be multiples of 8 which is ensured
@@ -104,6 +107,7 @@ static inline u64 get_u64(const struct canfd_frame *cp, int offset)
struct bcm_op {
struct list_head list;
struct rcu_head rcu;
+ struct work_struct work;
int ifindex;
canid_t can_id;
u32 flags;
@@ -256,7 +260,7 @@ static int bcm_proc_show(struct seq_file *m, void *v)
(reduction == 100) ? "near " : "", reduction);
}
- list_for_each_entry(op, &bo->tx_ops, list) {
+ list_for_each_entry_rcu(op, &bo->tx_ops, list) {
seq_printf(m, "tx_op: %03X %s ", op->can_id,
bcm_proc_getifname(net, ifname, op->ifindex));
@@ -788,9 +792,12 @@ static struct bcm_op *bcm_find_op(struct list_head *ops,
return NULL;
}
-static void bcm_free_op_rcu(struct rcu_head *rcu_head)
+static void bcm_free_op_work(struct work_struct *work)
{
- struct bcm_op *op = container_of(rcu_head, struct bcm_op, rcu);
+ struct bcm_op *op = container_of(work, struct bcm_op, work);
+
+ hrtimer_cancel(&op->timer);
+ hrtimer_cancel(&op->thrtimer);
if ((op->frames) && (op->frames != &op->sframe))
kfree(op->frames);
@@ -798,9 +805,23 @@ static void bcm_free_op_rcu(struct rcu_head *rcu_head)
if ((op->last_frames) && (op->last_frames != &op->last_sframe))
kfree(op->last_frames);
+ /* the last possible access to op->timer/op->thrtimer has now
+ * happened above via hrtimer_cancel() - op->sk is no longer
+ * needed by any pending timer callback, so drop our reference
+ */
+ sock_put(op->sk);
+
kfree(op);
}
+static void bcm_free_op_rcu(struct rcu_head *rcu_head)
+{
+ struct bcm_op *op = container_of(rcu_head, struct bcm_op, rcu);
+
+ INIT_WORK(&op->work, bcm_free_op_work);
+ queue_work(bcm_wq, &op->work);
+}
+
static void bcm_remove_op(struct bcm_op *op)
{
hrtimer_cancel(&op->timer);
@@ -925,6 +946,7 @@ static int bcm_tx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg,
struct bcm_sock *bo = bcm_sk(sk);
struct bcm_op *op;
struct canfd_frame *cf;
+ bool add_op_to_list = false;
unsigned int i;
int err;
@@ -1055,6 +1077,7 @@ static int bcm_tx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg,
/* bcm_can_tx / bcm_tx_timeout_handler needs this */
op->sk = sk;
+ sock_hold(sk);
op->ifindex = ifindex;
/* initialize uninitialized (kzalloc) structure */
@@ -1065,8 +1088,7 @@ static int bcm_tx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg,
hrtimer_setup(&op->thrtimer, hrtimer_dummy_timeout, CLOCK_MONOTONIC,
HRTIMER_MODE_REL_SOFT);
- /* add this bcm_op to the list of the tx_ops */
- list_add(&op->list, &bo->tx_ops);
+ add_op_to_list = true;
} /* if ((op = bcm_find_op(&bo->tx_ops, msg_head->can_id, ifindex))) */
@@ -1088,6 +1110,10 @@ static int bcm_tx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg,
op->flags |= TX_ANNOUNCE;
}
+ /* add this bcm_op to the list of the tx_ops? */
+ if (add_op_to_list)
+ list_add_rcu(&op->list, &bo->tx_ops);
+
if (op->flags & TX_ANNOUNCE)
bcm_can_tx(op);
@@ -1216,6 +1242,7 @@ static int bcm_rx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg,
/* bcm_can_tx / bcm_tx_timeout_handler needs this */
op->sk = sk;
+ sock_hold(sk);
op->ifindex = ifindex;
/* ifindex for timeout events w/o previous frame reception */
@@ -1227,9 +1254,6 @@ static int bcm_rx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg,
hrtimer_setup(&op->thrtimer, bcm_rx_thr_handler, CLOCK_MONOTONIC,
HRTIMER_MODE_REL_SOFT);
- /* add this bcm_op to the list of the rx_ops */
- list_add(&op->list, &bo->rx_ops);
-
/* call can_rx_register() */
do_rx_register = 1;
@@ -1295,6 +1319,11 @@ static int bcm_rx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg,
op->rx_reg_dev = dev;
dev_put(dev);
+ } else {
+ /* the requested device is gone - do not
+ * silently succeed without registering
+ */
+ err = -ENODEV;
}
} else
@@ -1303,10 +1332,12 @@ static int bcm_rx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg,
bcm_rx_handler, op, "bcm", sk);
if (err) {
/* this bcm rx op is broken -> remove it */
- list_del_rcu(&op->list);
bcm_remove_op(op);
return err;
}
+
+ /* add this bcm_op to the list of the rx_ops */
+ list_add_rcu(&op->list, &bo->rx_ops);
}
return msg_head->nframes * op->cfsiz + MHSIZ;
@@ -1364,12 +1395,13 @@ static int bcm_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
{
struct sock *sk = sock->sk;
struct bcm_sock *bo = bcm_sk(sk);
- int ifindex = bo->ifindex; /* default ifindex for this bcm_op */
+ int ifindex;
struct bcm_msg_head msg_head;
int cfsiz;
int ret; /* read bytes or error codes as return value */
- if (!bo->bound)
+ /* Lockless fast-path check for bound socket */
+ if (!READ_ONCE(bo->bound))
return -ENOTCONN;
/* check for valid message length from userspace */
@@ -1385,17 +1417,38 @@ static int bcm_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
if ((size - MHSIZ) % cfsiz)
return -EINVAL;
+ lock_sock(sk);
+
+ /* Re-validate under the socket lock: a concurrent bcm_notify()
+ * may have unbound this socket (device removal) after the
+ * lockless fast-path check above. bo->ifindex is only ever
+ * mutated under lock_sock(), so reading it here - instead of
+ * before taking the lock - guarantees it can't be observed
+ * torn against bo->bound.
+ */
+ if (!bo->bound) {
+ ret = -ENOTCONN;
+ goto out_release;
+ }
+
+ /* default ifindex for this bcm_op */
+ ifindex = bo->ifindex;
+
/* check for alternative ifindex for this bcm_op */
if (!ifindex && msg->msg_name) {
/* no bound device as default => check msg_name */
DECLARE_SOCKADDR(struct sockaddr_can *, addr, msg->msg_name);
- if (msg->msg_namelen < BCM_MIN_NAMELEN)
- return -EINVAL;
+ if (msg->msg_namelen < BCM_MIN_NAMELEN) {
+ ret = -EINVAL;
+ goto out_release;
+ }
- if (addr->can_family != AF_CAN)
- return -EINVAL;
+ if (addr->can_family != AF_CAN) {
+ ret = -EINVAL;
+ goto out_release;
+ }
/* ifindex from sendto() */
ifindex = addr->can_ifindex;
@@ -1404,20 +1457,21 @@ static int bcm_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
struct net_device *dev;
dev = dev_get_by_index(sock_net(sk), ifindex);
- if (!dev)
- return -ENODEV;
+ if (!dev) {
+ ret = -ENODEV;
+ goto out_release;
+ }
if (dev->type != ARPHRD_CAN) {
dev_put(dev);
- return -ENODEV;
+ ret = -ENODEV;
+ goto out_release;
}
dev_put(dev);
}
}
- lock_sock(sk);
-
switch (msg_head.opcode) {
case TX_SETUP:
@@ -1467,6 +1521,7 @@ static int bcm_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
break;
}
+out_release:
release_sock(sk);
return ret;
@@ -1503,7 +1558,12 @@ static void bcm_notify(struct bcm_sock *bo, unsigned long msg,
bo->bcm_proc_read = NULL;
}
#endif
- bo->bound = 0;
+ /* Paired with the lockless fast-path check in
+ * bcm_sendmsg(); bo->ifindex itself is only ever
+ * accessed under lock_sock() so it needs no
+ * annotation.
+ */
+ WRITE_ONCE(bo->bound, 0);
bo->ifindex = 0;
notify_enodev = 1;
}
@@ -1607,8 +1667,10 @@ static int bcm_release(struct socket *sock)
remove_proc_entry(bo->procname, net->can.bcmproc_dir);
#endif /* CONFIG_PROC_FS */
- list_for_each_entry_safe(op, next, &bo->tx_ops, list)
+ list_for_each_entry_safe(op, next, &bo->tx_ops, list) {
+ list_del_rcu(&op->list);
bcm_remove_op(op);
+ }
list_for_each_entry_safe(op, next, &bo->rx_ops, list) {
/*
@@ -1639,12 +1701,14 @@ static int bcm_release(struct socket *sock)
synchronize_rcu();
- list_for_each_entry_safe(op, next, &bo->rx_ops, list)
+ list_for_each_entry_safe(op, next, &bo->rx_ops, list) {
+ list_del_rcu(&op->list);
bcm_remove_op(op);
+ }
/* remove device reference */
if (bo->bound) {
- bo->bound = 0;
+ WRITE_ONCE(bo->bound, 0);
bo->ifindex = 0;
}
@@ -1714,7 +1778,10 @@ static int bcm_connect(struct socket *sock, struct sockaddr *uaddr, int len,
}
#endif /* CONFIG_PROC_FS */
- bo->bound = 1;
+ /* bo->ifindex above is fully assigned before this point; pairs
+ * with the lockless fast-path check in bcm_sendmsg()
+ */
+ WRITE_ONCE(bo->bound, 1);
fail:
release_sock(sk);
@@ -1830,11 +1897,15 @@ static int __init bcm_module_init(void)
{
int err;
+ bcm_wq = alloc_workqueue("can-bcm-wq", WQ_UNBOUND, 0);
+ if (!bcm_wq)
+ return -ENOMEM;
+
pr_info("can: broadcast manager protocol\n");
err = register_pernet_subsys(&canbcm_pernet_ops);
if (err)
- return err;
+ goto register_pernet_failed;
err = register_netdevice_notifier(&canbcm_notifier);
if (err)
@@ -1852,6 +1923,8 @@ register_proto_failed:
unregister_netdevice_notifier(&canbcm_notifier);
register_notifier_failed:
unregister_pernet_subsys(&canbcm_pernet_ops);
+register_pernet_failed:
+ destroy_workqueue(bcm_wq);
return err;
}
@@ -1860,6 +1933,8 @@ static void __exit bcm_module_exit(void)
can_proto_unregister(&bcm_can_proto);
unregister_netdevice_notifier(&canbcm_notifier);
unregister_pernet_subsys(&canbcm_pernet_ops);
+ rcu_barrier();
+ destroy_workqueue(bcm_wq);
}
module_init(bcm_module_init);
diff --git a/net/can/isotp.c b/net/can/isotp.c
index 12eabfd47d82..c21d816a5274 100644
--- a/net/can/isotp.c
+++ b/net/can/isotp.c
@@ -151,11 +151,13 @@ struct isotp_sock {
struct sock sk;
int bound;
int ifindex;
+ struct net_device *dev;
+ netdevice_tracker dev_tracker;
canid_t txid;
canid_t rxid;
ktime_t tx_gap;
ktime_t lastrxcf_tstamp;
- struct hrtimer rxtimer, txtimer, txfrtimer;
+ struct hrtimer rxtimer, txtimer, txfrtimer, echotimer;
struct can_isotp_options opt;
struct can_isotp_fc_options rxfc, txfc;
struct can_isotp_ll_options ll;
@@ -163,6 +165,7 @@ struct isotp_sock {
u32 force_tx_stmin;
u32 force_rx_stmin;
u32 cfecho; /* consecutive frame echo tag */
+ u32 tx_gen; /* generation, bumped per new tx transfer */
struct tpcon rx, tx;
struct list_head notifier;
wait_queue_head_t wait;
@@ -370,6 +373,15 @@ static int isotp_rcv_fc(struct isotp_sock *so, struct canfd_frame *cf, int ae)
hrtimer_cancel(&so->txtimer);
+ /* isotp_tx_timeout() may have given up on this job while
+ * hrtimer_cancel() above waited for it to finish; so->rx_lock
+ * (held by our caller isotp_rcv()) rules out a concurrent claim,
+ * so a plain recheck is enough here.
+ */
+ if (so->tx.state != ISOTP_WAIT_FC &&
+ so->tx.state != ISOTP_WAIT_FIRST_FC)
+ return 1;
+
if ((cf->len < ae + FC_CONTENT_SZ) ||
((so->opt.flags & ISOTP_CHECK_PADDING) &&
check_pad(so, cf, ae + FC_CONTENT_SZ, so->opt.rxpad_content))) {
@@ -416,7 +428,7 @@ static int isotp_rcv_fc(struct isotp_sock *so, struct canfd_frame *cf, int ae)
so->tx.bs = 0;
so->tx.state = ISOTP_SENDING;
/* send CF frame and enable echo timeout handling */
- hrtimer_start(&so->txtimer, ktime_set(ISOTP_ECHO_TIMEOUT, 0),
+ hrtimer_start(&so->echotimer, ktime_set(ISOTP_ECHO_TIMEOUT, 0),
HRTIMER_MODE_REL_SOFT);
isotp_send_cframe(so);
break;
@@ -569,6 +581,14 @@ static int isotp_rcv_cf(struct sock *sk, struct canfd_frame *cf, int ae,
hrtimer_cancel(&so->rxtimer);
+ /* isotp_rx_timer_handler() may have raced us for so->rx.state
+ * while hrtimer_cancel() above waited for it to finish, already
+ * reporting ETIMEDOUT and resetting the reception; don't process
+ * this CF into a reassembly that has already been given up on.
+ */
+ if (so->rx.state != ISOTP_WAIT_DATA)
+ return 1;
+
/* CFs are never longer than the FF */
if (cf->len > so->rx.ll_dl)
return 1;
@@ -858,20 +878,36 @@ static void isotp_rcv_echo(struct sk_buff *skb, void *data)
struct canfd_frame *cf = (struct canfd_frame *)skb->data;
/* only handle my own local echo CF/SF skb's (no FF!) */
- if (skb->sk != sk || so->cfecho != *(u32 *)cf->data)
+ if (skb->sk != sk)
return;
+ /* unlike isotp_rcv_fc()/isotp_rcv_cf(), not already under so->rx_lock
+ * (no isotp_rcv() caller here), so take it ourselves
+ */
+ spin_lock(&so->rx_lock);
+
+ /* so->cfecho may since belong to a new transfer; recheck under lock */
+ if (so->cfecho != *(u32 *)cf->data)
+ goto out_unlock;
+
/* cancel local echo timeout */
- hrtimer_cancel(&so->txtimer);
+ hrtimer_cancel(&so->echotimer);
/* local echo skb with consecutive frame has been consumed */
so->cfecho = 0;
+ /* claiming a transfer also takes so->rx_lock, so a plain recheck
+ * is enough: so->tx.state can't have flipped to ISOTP_SENDING for
+ * a new claim while we're still in here
+ */
+ if (so->tx.state != ISOTP_SENDING)
+ goto out_unlock;
+
if (so->tx.idx >= so->tx.len) {
/* we are done */
so->tx.state = ISOTP_IDLE;
wake_up_interruptible(&so->wait);
- return;
+ goto out_unlock;
}
if (so->txfc.bs && so->tx.bs >= so->txfc.bs) {
@@ -879,53 +915,83 @@ static void isotp_rcv_echo(struct sk_buff *skb, void *data)
so->tx.state = ISOTP_WAIT_FC;
hrtimer_start(&so->txtimer, ktime_set(ISOTP_FC_TIMEOUT, 0),
HRTIMER_MODE_REL_SOFT);
- return;
+ goto out_unlock;
}
/* no gap between data frames needed => use burst mode */
if (!so->tx_gap) {
/* enable echo timeout handling */
- hrtimer_start(&so->txtimer, ktime_set(ISOTP_ECHO_TIMEOUT, 0),
+ hrtimer_start(&so->echotimer, ktime_set(ISOTP_ECHO_TIMEOUT, 0),
HRTIMER_MODE_REL_SOFT);
isotp_send_cframe(so);
- return;
+ goto out_unlock;
}
/* start timer to send next consecutive frame with correct delay */
hrtimer_start(&so->txfrtimer, so->tx_gap, HRTIMER_MODE_REL_SOFT);
+
+out_unlock:
+ spin_unlock(&so->rx_lock);
}
-static enum hrtimer_restart isotp_tx_timer_handler(struct hrtimer *hrtimer)
+/* shared by so->txtimer's and so->echotimer's callbacks. Both timers get
+ * cancelled under so->rx_lock elsewhere, so this must stay lock-free to
+ * avoid deadlocking with that; uses so->tx_gen instead to avoid tainting
+ * a new transfer with an error from the one that just timed out.
+ */
+static enum hrtimer_restart isotp_tx_timeout(struct isotp_sock *so)
{
- struct isotp_sock *so = container_of(hrtimer, struct isotp_sock,
- txtimer);
struct sock *sk = &so->sk;
+ u32 gen = READ_ONCE(so->tx_gen);
+ u32 old_state = READ_ONCE(so->tx.state);
/* don't handle timeouts in IDLE or SHUTDOWN state */
- if (so->tx.state == ISOTP_IDLE || so->tx.state == ISOTP_SHUTDOWN)
+ if (old_state == ISOTP_IDLE || old_state == ISOTP_SHUTDOWN)
+ return HRTIMER_NORESTART;
+
+ /* only claim the timeout if the state is still unchanged */
+ if (cmpxchg(&so->tx.state, old_state, ISOTP_IDLE) != old_state)
return HRTIMER_NORESTART;
/* we did not get any flow control or echo frame in time */
- /* report 'communication error on send' */
- sk->sk_err = ECOMM;
- if (!sock_flag(sk, SOCK_DEAD))
- sk_error_report(sk);
+ if (READ_ONCE(so->tx_gen) == gen) {
+ /* report 'communication error on send' */
+ sk->sk_err = ECOMM;
+ if (!sock_flag(sk, SOCK_DEAD))
+ sk_error_report(sk);
+ }
- /* reset tx state */
- so->tx.state = ISOTP_IDLE;
wake_up_interruptible(&so->wait);
return HRTIMER_NORESTART;
}
+/* so->txtimer: fires when a Flow Control frame does not arrive in time */
+static enum hrtimer_restart isotp_tx_timer_handler(struct hrtimer *hrtimer)
+{
+ struct isotp_sock *so = container_of(hrtimer, struct isotp_sock,
+ txtimer);
+
+ return isotp_tx_timeout(so);
+}
+
+/* so->echotimer: fires when a sent CF/SF's local echo does not arrive */
+static enum hrtimer_restart isotp_echo_timer_handler(struct hrtimer *hrtimer)
+{
+ struct isotp_sock *so = container_of(hrtimer, struct isotp_sock,
+ echotimer);
+
+ return isotp_tx_timeout(so);
+}
+
static enum hrtimer_restart isotp_txfr_timer_handler(struct hrtimer *hrtimer)
{
struct isotp_sock *so = container_of(hrtimer, struct isotp_sock,
txfrtimer);
/* start echo timeout handling and cover below protocol error */
- hrtimer_start(&so->txtimer, ktime_set(ISOTP_ECHO_TIMEOUT, 0),
+ hrtimer_start(&so->echotimer, ktime_set(ISOTP_ECHO_TIMEOUT, 0),
HRTIMER_MODE_REL_SOFT);
/* cfecho should be consumed by isotp_rcv_echo() here */
@@ -945,13 +1011,24 @@ static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
int ae = (so->opt.flags & CAN_ISOTP_EXTEND_ADDR) ? 1 : 0;
int wait_tx_done = (so->opt.flags & CAN_ISOTP_WAIT_TX_DONE) ? 1 : 0;
s64 hrtimer_sec = ISOTP_ECHO_TIMEOUT;
+ struct hrtimer *tx_hrt = &so->echotimer;
+ u32 new_state = ISOTP_SENDING;
int off;
int err;
if (!so->bound || so->tx.state == ISOTP_SHUTDOWN)
return -EADDRNOTAVAIL;
- while (cmpxchg(&so->tx.state, ISOTP_IDLE, ISOTP_SENDING) != ISOTP_IDLE) {
+ /* claim the socket under so->rx_lock: this serializes the claim
+ * with the RX path and with sendmsg()'s own error paths below, so
+ * none of them can ever see a transfer mid-claim
+ */
+ for (;;) {
+ spin_lock_bh(&so->rx_lock);
+ if (READ_ONCE(so->tx.state) == ISOTP_IDLE)
+ break;
+ spin_unlock_bh(&so->rx_lock);
+
/* we do not support multiple buffers - for now */
if (msg->msg_flags & MSG_DONTWAIT)
return -EAGAIN;
@@ -960,9 +1037,29 @@ static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
return -EADDRNOTAVAIL;
/* wait for complete transmission of current pdu */
- err = 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;
+ return err;
+ }
+
+ /* new transfer: bump so->tx_gen and drain the old one's timers,
+ * still under the so->rx_lock we just claimed the socket with
+ */
+ WRITE_ONCE(so->tx.state, ISOTP_SENDING);
+ WRITE_ONCE(so->tx_gen, READ_ONCE(so->tx_gen) + 1);
+ hrtimer_cancel(&so->txtimer);
+ hrtimer_cancel(&so->echotimer);
+ hrtimer_cancel(&so->txfrtimer);
+ so->cfecho = 0;
+ spin_unlock_bh(&so->rx_lock);
+
+ /* so->bound is only checked once above - a wakeup may have
+ * unbound/rebound the socket meanwhile, so re-validate it
+ */
+ if (!so->bound) {
+ err = -EADDRNOTAVAIL;
+ goto err_out_drop;
}
/* PDU size > default => try max_pdu_size */
@@ -1067,18 +1164,33 @@ static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
so->cfecho = *(u32 *)cf->data;
} else {
/* standard flow control check */
- so->tx.state = ISOTP_WAIT_FIRST_FC;
+ new_state = ISOTP_WAIT_FIRST_FC;
/* start timeout for FC */
hrtimer_sec = ISOTP_FC_TIMEOUT;
+ tx_hrt = &so->txtimer;
/* no CF echo tag for isotp_rcv_echo() (FF-mode) */
so->cfecho = 0;
}
}
- hrtimer_start(&so->txtimer, ktime_set(hrtimer_sec, 0),
+ spin_lock_bh(&so->rx_lock);
+ if (so->tx.state == ISOTP_SHUTDOWN) {
+ /* isotp_release() has since taken over and already drained
+ * our timers - don't send into a socket that's going away
+ */
+ spin_unlock_bh(&so->rx_lock);
+ kfree_skb(skb);
+ dev_put(dev);
+ wake_up_interruptible(&so->wait);
+ return -EADDRNOTAVAIL;
+ }
+ /* WAIT_FIRST_FC for standard FF, else stays ISOTP_SENDING */
+ so->tx.state = new_state;
+ hrtimer_start(tx_hrt, ktime_set(hrtimer_sec, 0),
HRTIMER_MODE_REL_SOFT);
+ spin_unlock_bh(&so->rx_lock);
/* send the first or only CAN frame */
cf->flags = so->ll.tx_flags;
@@ -1091,13 +1203,10 @@ static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
pr_notice_once("can-isotp: %s: can_send_ret %pe\n",
__func__, ERR_PTR(err));
+ spin_lock_bh(&so->rx_lock);
/* no transmission -> no timeout monitoring */
- hrtimer_cancel(&so->txtimer);
-
- /* reset consecutive frame echo tag */
- so->cfecho = 0;
-
- goto err_out_drop;
+ hrtimer_cancel(tx_hrt);
+ goto err_out_drop_locked;
}
if (wait_tx_done) {
@@ -1113,14 +1222,21 @@ static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
return size;
+err_out_drop:
+ /* claimed but nothing sent yet - no timer to cancel */
+ spin_lock_bh(&so->rx_lock);
+ goto err_out_drop_locked;
err_event_drop:
- /* got signal: force tx state machine to be idle */
- so->tx.state = ISOTP_IDLE;
+ /* interrupted waiting on our own transfer - drain its timers */
+ spin_lock_bh(&so->rx_lock);
hrtimer_cancel(&so->txfrtimer);
hrtimer_cancel(&so->txtimer);
-err_out_drop:
- /* drop this PDU and unlock a potential wait queue */
+ hrtimer_cancel(&so->echotimer);
+err_out_drop_locked:
+ /* release the claim; so->rx_lock still held from above */
+ so->cfecho = 0;
so->tx.state = ISOTP_IDLE;
+ spin_unlock_bh(&so->rx_lock);
wake_up_interruptible(&so->wait);
return err;
@@ -1182,13 +1298,20 @@ static int isotp_release(struct socket *sock)
so = isotp_sk(sk);
net = sock_net(sk);
- /* wait for complete transmission of current pdu */
- while (wait_event_interruptible(so->wait, so->tx.state == ISOTP_IDLE) == 0 &&
- cmpxchg(&so->tx.state, ISOTP_IDLE, ISOTP_SHUTDOWN) != ISOTP_IDLE)
+ /* best-effort: wait for a running pdu to finish, but don't block on
+ * it forever - give up after the first signal
+ */
+ while (so->tx.state != ISOTP_IDLE &&
+ wait_event_interruptible(so->wait, so->tx.state == ISOTP_IDLE) == 0)
;
- /* force state machines to be idle also when a signal occurred */
+ /* claim the socket under so->rx_lock like sendmsg() does, so its
+ * claim can't race the forced ISOTP_SHUTDOWN below; force it
+ * unconditionally, even when a signal cut the wait above short
+ */
+ spin_lock_bh(&so->rx_lock);
so->tx.state = ISOTP_SHUTDOWN;
+ spin_unlock_bh(&so->rx_lock);
so->rx.state = ISOTP_IDLE;
spin_lock(&isotp_notifier_lock);
@@ -1200,36 +1323,43 @@ static int isotp_release(struct socket *sock)
list_del(&so->notifier);
spin_unlock(&isotp_notifier_lock);
+ rtnl_lock();
lock_sock(sk);
- /* remove current filters & unregister */
- if (so->bound) {
- if (so->ifindex) {
- struct net_device *dev;
-
- dev = dev_get_by_index(net, so->ifindex);
- if (dev) {
- if (isotp_register_rxid(so))
- can_rx_unregister(net, dev, so->rxid,
- SINGLE_MASK(so->rxid),
- isotp_rcv, sk);
-
- can_rx_unregister(net, dev, so->txid,
- SINGLE_MASK(so->txid),
- isotp_rcv_echo, sk);
- dev_put(dev);
- synchronize_rcu();
- }
- }
+ /* remove current filters & unregister
+ * tracked reference so->dev is taken at bind() time with rtnl_lock
+ */
+ if (so->bound && so->dev) {
+ if (isotp_register_rxid(so))
+ can_rx_unregister(net, so->dev, so->rxid,
+ SINGLE_MASK(so->rxid),
+ isotp_rcv, sk);
+
+ can_rx_unregister(net, so->dev, so->txid,
+ SINGLE_MASK(so->txid),
+ isotp_rcv_echo, sk);
+ netdev_put(so->dev, &so->dev_tracker);
}
+ so->ifindex = 0;
+ so->bound = 0;
+ so->dev = NULL;
+
+ rtnl_unlock();
+
+ /* Always wait for a grace period before touching the timers below.
+ * A concurrent NETDEV_UNREGISTER may have already unregistered our
+ * filters and cleared so->bound in isotp_notify() without waiting
+ * for in-flight isotp_rcv() callers to finish, so this call must not
+ * be skipped just because so->bound is already 0 here.
+ */
+ synchronize_rcu();
+
hrtimer_cancel(&so->txfrtimer);
hrtimer_cancel(&so->txtimer);
+ hrtimer_cancel(&so->echotimer);
hrtimer_cancel(&so->rxtimer);
- so->ifindex = 0;
- so->bound = 0;
-
sock_orphan(sk);
sock->sk = NULL;
@@ -1284,6 +1414,7 @@ static int isotp_bind(struct socket *sock, struct sockaddr *uaddr, int len)
if (!addr->can_ifindex)
return -ENODEV;
+ rtnl_lock();
lock_sock(sk);
if (so->bound) {
@@ -1291,6 +1422,17 @@ static int isotp_bind(struct socket *sock, struct sockaddr *uaddr, int len)
goto out;
}
+ /* A transmission or reception that outlived a previous binding
+ * (unbound by NETDEV_UNREGISTER) may still be draining; the FC/echo
+ * and RX watchdog timers bound how long this takes. Checked together
+ * with so->bound in the same lock_sock() section above, so there is
+ * no window in which a concurrent isotp_notify() could be missed.
+ */
+ if (so->tx.state != ISOTP_IDLE || so->rx.state != ISOTP_IDLE) {
+ err = -EAGAIN;
+ goto out;
+ }
+
/* ensure different CAN IDs when the rx_id is to be registered */
if (isotp_register_rxid(so) && rx_id == tx_id) {
err = -EADDRNOTAVAIL;
@@ -1303,14 +1445,12 @@ static int isotp_bind(struct socket *sock, struct sockaddr *uaddr, int len)
goto out;
}
if (dev->type != ARPHRD_CAN) {
- dev_put(dev);
err = -ENODEV;
- goto out;
+ goto out_put_dev;
}
if (READ_ONCE(dev->mtu) < so->ll.mtu) {
- dev_put(dev);
err = -EINVAL;
- goto out;
+ goto out_put_dev;
}
if (!(dev->flags & IFF_UP))
notify_enetdown = 1;
@@ -1328,16 +1468,25 @@ static int isotp_bind(struct socket *sock, struct sockaddr *uaddr, int len)
can_rx_register(net, dev, tx_id, SINGLE_MASK(tx_id),
isotp_rcv_echo, sk, "isotpe", sk);
- dev_put(dev);
-
/* switch to new settings */
so->ifindex = ifindex;
so->rxid = rx_id;
so->txid = tx_id;
so->bound = 1;
+ /* bind() ok -> hold a reference for so->dev so that isotp_release()
+ * can safely reach the device later, even if a concurrent
+ * NETDEV_UNREGISTER has already unlisted it by ifindex.
+ */
+ so->dev = dev;
+ netdev_hold(so->dev, &so->dev_tracker, GFP_KERNEL);
+
+out_put_dev:
+ /* remove potential reference from dev_get_by_index() */
+ dev_put(dev);
out:
release_sock(sk);
+ rtnl_unlock();
if (notify_enetdown) {
sk->sk_err = ENETDOWN;
@@ -1540,7 +1689,7 @@ static void isotp_notify(struct isotp_sock *so, unsigned long msg,
if (!net_eq(dev_net(dev), sock_net(sk)))
return;
- if (so->ifindex != dev->ifindex)
+ if (so->dev != dev)
return;
switch (msg) {
@@ -1556,10 +1705,12 @@ static void isotp_notify(struct isotp_sock *so, unsigned long msg,
can_rx_unregister(dev_net(dev), dev, so->txid,
SINGLE_MASK(so->txid),
isotp_rcv_echo, sk);
+ netdev_put(so->dev, &so->dev_tracker);
}
so->ifindex = 0;
so->bound = 0;
+ so->dev = NULL;
release_sock(sk);
sk->sk_err = ENODEV;
@@ -1619,6 +1770,7 @@ static int isotp_init(struct sock *sk)
so->ifindex = 0;
so->bound = 0;
+ so->dev = NULL;
so->opt.flags = CAN_ISOTP_DEFAULT_FLAGS;
so->opt.ext_address = CAN_ISOTP_DEFAULT_EXT_ADDRESS;
@@ -1645,10 +1797,14 @@ static int isotp_init(struct sock *sk)
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);
+ 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->echotimer, isotp_echo_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);
generated by cgit v1.2.3 (git 2.25.1) at 2026-07-25 15:43:10 +0000