diff options
Diffstat (limited to 'net/can')
| -rw-r--r-- | net/can/bcm.c | 646 | ||||
| -rw-r--r-- | net/can/isotp.c | 298 |
2 files changed, 720 insertions, 224 deletions
diff --git a/net/can/bcm.c b/net/can/bcm.c index a4bef2c48a55..3d637a1e0ac1 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/can.h> #include <net/sock.h> @@ -92,6 +93,8 @@ 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 @@ -105,14 +108,16 @@ 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; - unsigned long frames_abs, frames_filtered; + atomic_long_t frames_abs, frames_filtered; struct bcm_timeval ival1, ival2; struct hrtimer timer, thrtimer; ktime_t rx_stamp, kt_ival1, kt_ival2, kt_lastmsg; int rx_ifindex; + int if_detected; /* first received ifindex in ANYDEV rx_op mode */ int cfsiz; u32 count; u32 nframes; @@ -124,7 +129,9 @@ struct bcm_op { struct canfd_frame last_sframe; struct sock *sk; struct net_device *rx_reg_dev; - spinlock_t bcm_tx_lock; /* protect currframe/count in runtime updates */ + netdevice_tracker rx_reg_dev_tracker; + spinlock_t bcm_tx_lock; /* protect tx data and timer updates */ + spinlock_t bcm_rx_update_lock; /* protect filter/timer data updates */ }; struct bcm_sock { @@ -224,10 +231,13 @@ static int bcm_proc_show(struct seq_file *m, void *v) list_for_each_entry_rcu(op, &bo->rx_ops, list) { - unsigned long reduction; + long reduction, frames_filtered, frames_abs; + + frames_filtered = atomic_long_read(&op->frames_filtered); + frames_abs = atomic_long_read(&op->frames_abs); /* print only active entries & prevent division by zero */ - if (!op->frames_abs) + if (!frames_abs) continue; seq_printf(m, "rx_op: %03X %-5s ", op->can_id, @@ -249,15 +259,15 @@ static int bcm_proc_show(struct seq_file *m, void *v) (long long)ktime_to_us(op->kt_ival2)); seq_printf(m, "# recv %ld (%ld) => reduction: ", - op->frames_filtered, op->frames_abs); + frames_filtered, frames_abs); - reduction = 100 - (op->frames_filtered * 100) / op->frames_abs; + reduction = 100 - (frames_filtered * 100) / frames_abs; seq_printf(m, "%s%ld%%\n", (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)); @@ -275,7 +285,8 @@ static int bcm_proc_show(struct seq_file *m, void *v) seq_printf(m, "t2=%lld ", (long long)ktime_to_us(op->kt_ival2)); - seq_printf(m, "# sent %ld\n", op->frames_abs); + seq_printf(m, "# sent %ld\n", + atomic_long_read(&op->frames_abs)); } seq_putc(m, '\n'); @@ -285,26 +296,50 @@ static int bcm_proc_show(struct seq_file *m, void *v) } #endif /* CONFIG_PROC_FS */ +static void bcm_update_rx_stats(struct bcm_op *op) +{ + /* prevent overflow of the reduction% calculation in bcm_proc_show() */ + if (atomic_long_inc_return(&op->frames_abs) > LONG_MAX / 100) { + atomic_long_set(&op->frames_filtered, 0); + atomic_long_set(&op->frames_abs, 0); + } +} + +static void bcm_update_tx_stats(struct bcm_op *op) +{ + /* tx_op has no reduction% calculation - use the full range and + * just keep the displayed counter non-negative on overflow + */ + if (atomic_long_inc_return(&op->frames_abs) == LONG_MAX) + atomic_long_set(&op->frames_abs, 0); +} + /* * bcm_can_tx - send the (next) CAN frame to the appropriate CAN interface * of the given bcm tx op */ -static void bcm_can_tx(struct bcm_op *op) +static void bcm_can_tx(struct bcm_op *op, struct canfd_frame *cf) { struct sk_buff *skb; struct can_skb_ext *csx; struct net_device *dev; - struct canfd_frame *cf; + struct canfd_frame cframe; + bool cyclic = !cf; + unsigned int idx = 0; int err; /* no target device? => exit */ if (!op->ifindex) return; - /* read currframe under lock protection */ - spin_lock_bh(&op->bcm_tx_lock); - cf = op->frames + op->cfsiz * op->currframe; - spin_unlock_bh(&op->bcm_tx_lock); + if (cyclic) { + /* read currframe under lock protection */ + spin_lock_bh(&op->bcm_tx_lock); + idx = op->currframe; + memcpy(&cframe, op->frames + op->cfsiz * idx, op->cfsiz); + cf = &cframe; + spin_unlock_bh(&op->bcm_tx_lock); + } dev = dev_get_by_index(sock_net(op->sk), op->ifindex); if (!dev) { @@ -335,16 +370,22 @@ static void bcm_can_tx(struct bcm_op *op) spin_lock_bh(&op->bcm_tx_lock); if (!err) - op->frames_abs++; + bcm_update_tx_stats(op); - op->currframe++; + /* only advance the cyclic sequence if nothing reset currframe while + * we were sending - a concurrent TX_RESET_MULTI_IDX means this + * frame's bookkeeping belongs to a sequence that no longer exists + */ + if (!cyclic || op->currframe == idx) { + op->currframe++; - /* reached last frame? */ - if (op->currframe >= op->nframes) - op->currframe = 0; + /* reached last frame? */ + if (op->currframe >= op->nframes) + op->currframe = 0; - if (op->count > 0) - op->count--; + if (op->count > 0) + op->count--; + } spin_unlock_bh(&op->bcm_tx_lock); out: @@ -433,12 +474,18 @@ static bool bcm_tx_set_expiry(struct bcm_op *op, struct hrtimer *hrt) { ktime_t ival; + spin_lock_bh(&op->bcm_tx_lock); + if (op->kt_ival1 && op->count) ival = op->kt_ival1; - else if (op->kt_ival2) + else if (op->kt_ival2) { ival = op->kt_ival2; - else + } else { + spin_unlock_bh(&op->bcm_tx_lock); return false; + } + + spin_unlock_bh(&op->bcm_tx_lock); hrtimer_set_expires(hrt, ktime_add(ktime_get(), ival)); return true; @@ -455,26 +502,48 @@ static enum hrtimer_restart bcm_tx_timeout_handler(struct hrtimer *hrtimer) { struct bcm_op *op = container_of(hrtimer, struct bcm_op, timer); struct bcm_msg_head msg_head; + bool tx_ival1, tx_ival2; + + /* snapshot kt_ival1/kt_ival2/count under lock to avoid torn + * ktime_t reads racing with concurrent bcm_tx_setup() updates + */ + spin_lock_bh(&op->bcm_tx_lock); + tx_ival1 = op->kt_ival1 && (op->count > 0); + tx_ival2 = !!op->kt_ival2; + spin_unlock_bh(&op->bcm_tx_lock); - if (op->kt_ival1 && (op->count > 0)) { - bcm_can_tx(op); - if (!op->count && (op->flags & TX_COUNTEVT)) { + if (tx_ival1) { + u32 flags, count; + struct bcm_timeval ival1, ival2; + bcm_can_tx(op, NULL); + + /* snapshot variables under lock to avoid torn reads racing + * with concurrent bcm_tx_setup() updates + */ + spin_lock_bh(&op->bcm_tx_lock); + flags = op->flags; + count = op->count; + ival1 = op->ival1; + ival2 = op->ival2; + spin_unlock_bh(&op->bcm_tx_lock); + + if (!count && (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; - msg_head.ival1 = op->ival1; - msg_head.ival2 = op->ival2; + msg_head.flags = flags; + msg_head.count = count; + msg_head.ival1 = ival1; + msg_head.ival2 = ival2; msg_head.can_id = op->can_id; msg_head.nframes = 0; bcm_send_to_user(op, &msg_head, NULL, 0); } - } else if (op->kt_ival2) { - bcm_can_tx(op); + } else if (tx_ival2) { + bcm_can_tx(op, NULL); } return bcm_tx_set_expiry(op, &op->timer) ? @@ -488,12 +557,9 @@ static void bcm_rx_changed(struct bcm_op *op, struct canfd_frame *data) { struct bcm_msg_head head; - /* update statistics */ - op->frames_filtered++; - - /* prevent statistics overflow */ - if (op->frames_filtered > ULONG_MAX/100) - op->frames_filtered = op->frames_abs = 0; + /* update statistics (frames_filtered <= frames_abs) */ + if (atomic_long_read(&op->frames_abs)) + atomic_long_inc(&op->frames_filtered); /* this element is not throttled anymore */ data->flags &= ~RX_THR; @@ -618,6 +684,8 @@ static enum hrtimer_restart bcm_rx_timeout_handler(struct hrtimer *hrtimer) struct bcm_op *op = container_of(hrtimer, struct bcm_op, timer); struct bcm_msg_head msg_head; + spin_lock_bh(&op->bcm_rx_update_lock); + /* if user wants to be informed, when cyclic CAN-Messages come back */ if ((op->flags & RX_ANNOUNCE_RESUME) && op->last_frames) { /* clear received CAN frames to indicate 'nothing received' */ @@ -634,6 +702,8 @@ static enum hrtimer_restart bcm_rx_timeout_handler(struct hrtimer *hrtimer) msg_head.can_id = op->can_id; msg_head.nframes = 0; + spin_unlock_bh(&op->bcm_rx_update_lock); + bcm_send_to_user(op, &msg_head, NULL, 0); return HRTIMER_NORESTART; @@ -682,15 +752,26 @@ static int bcm_rx_thr_flush(struct bcm_op *op) static enum hrtimer_restart bcm_rx_thr_handler(struct hrtimer *hrtimer) { struct bcm_op *op = container_of(hrtimer, struct bcm_op, thrtimer); + enum hrtimer_restart ret; + + spin_lock_bh(&op->bcm_rx_update_lock); - if (bcm_rx_thr_flush(op)) { + /* kt_ival2 may have been concurrently cleared by bcm_rx_setup() + * before it cancels this timer - never forward with a zero + * interval in that case. + */ + if (bcm_rx_thr_flush(op) && op->kt_ival2) { hrtimer_forward_now(hrtimer, op->kt_ival2); - return HRTIMER_RESTART; + ret = HRTIMER_RESTART; } else { /* rearm throttle handling */ op->kt_lastmsg = 0; - return HRTIMER_NORESTART; + ret = HRTIMER_NORESTART; } + + spin_unlock_bh(&op->bcm_rx_update_lock); + + return ret; } /* @@ -700,8 +781,10 @@ static void bcm_rx_handler(struct sk_buff *skb, void *data) { struct bcm_op *op = (struct bcm_op *)data; const struct canfd_frame *rxframe = (struct canfd_frame *)skb->data; + struct canfd_frame rtrframe; unsigned int i; unsigned char traffic_flags; + bool rtr_frame; if (op->can_id != rxframe->can_id) return; @@ -715,22 +798,59 @@ static void bcm_rx_handler(struct sk_buff *skb, void *data) return; } + /* An ANYDEV op with an active RX timeout and/or throttle timer + * tracks a single source interface: claim the first interface that + * delivers a matching frame and reject frames from any other one, + * before hrtimer_cancel() below can touch op->timer - this avoids + * racing bcm_rx_timeout_handler() across concurrent interfaces. + * RX_RTR_FRAME ops are excluded, as kt_ival1/kt_ival2 may briefly + * hold a stale value from an earlier non-RTR configuration. + */ + if (!op->ifindex) { + spin_lock_bh(&op->bcm_rx_update_lock); + + if (!(op->flags & RX_RTR_FRAME) && + (op->kt_ival1 || op->kt_ival2)) { + /* don't claim to vanishing interface */ + if (!op->if_detected && + READ_ONCE(skb->dev->reg_state) == NETREG_REGISTERED) + op->if_detected = skb->dev->ifindex; + + if (op->if_detected != skb->dev->ifindex) { + spin_unlock_bh(&op->bcm_rx_update_lock); + return; + } + } + + spin_unlock_bh(&op->bcm_rx_update_lock); + } + /* disable timeout */ hrtimer_cancel(&op->timer); - /* save rx timestamp */ - op->rx_stamp = skb->tstamp; - /* save originator for recvfrom() */ - op->rx_ifindex = skb->dev->ifindex; - /* update statistics */ - op->frames_abs++; + /* op->flags/op->frames may be updated concurrently by bcm_rx_setup() */ + spin_lock_bh(&op->bcm_rx_update_lock); + + rtr_frame = op->flags & RX_RTR_FRAME; + if (rtr_frame) { + bcm_update_rx_stats(op); + /* snapshot RTR content under lock */ + memcpy(&rtrframe, op->frames, op->cfsiz); + spin_unlock_bh(&op->bcm_rx_update_lock); - if (op->flags & RX_RTR_FRAME) { /* send reply for RTR-request (placed in op->frames[0]) */ - bcm_can_tx(op); + bcm_can_tx(op, &rtrframe); return; } + /* update statistics in the same critical section as bcm_rx_changed() + * below: frames_filtered must never be checked/incremented against a + * frames_abs snapshot from a concurrent bcm_rx_handler() call on + * another CPU for the same (wildcard) op, or frames_filtered can end + * up larger than frames_abs. + */ + bcm_update_rx_stats(op); + /* compute flags to distinguish between own/local/remote CAN traffic */ traffic_flags = 0; if (skb->sk) { @@ -739,6 +859,13 @@ static void bcm_rx_handler(struct sk_buff *skb, void *data) traffic_flags |= RX_OWN; } + /* save rx timestamp and originator for recvfrom() under lock: an + * ANYDEV op without an active timer can still run concurrently on + * different CPUs, so content and meta data must be bundled here. + */ + op->rx_stamp = skb->tstamp; + op->rx_ifindex = skb->dev->ifindex; + if (op->flags & RX_FILTER_ID) { /* the easiest case */ bcm_rx_update_and_send(op, op->last_frames, rxframe, @@ -774,6 +901,8 @@ static void bcm_rx_handler(struct sk_buff *skb, void *data) rx_starttimer: bcm_rx_starttimer(op); + + spin_unlock_bh(&op->bcm_rx_update_lock); } /* @@ -793,9 +922,12 @@ 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); @@ -803,9 +935,23 @@ 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); @@ -822,6 +968,7 @@ static void bcm_rx_unreg(struct net_device *dev, struct bcm_op *op) /* mark as removed subscription */ op->rx_reg_dev = NULL; + netdev_put(dev, &op->rx_reg_dev_tracker); } else printk(KERN_ERR "can-bcm: bcm_rx_unreg: registered device " "mismatch %p %p\n", op->rx_reg_dev, dev); @@ -852,17 +999,14 @@ static int bcm_delete_rx_op(struct list_head *ops, struct bcm_msg_head *mh, * Only remove subscriptions that had not * been removed due to NETDEV_UNREGISTER * in bcm_notifier() + * + * op->rx_reg_dev is a tracked reference taken + * when the subscription was registered, so it + * stays valid here even if a concurrent + * NETDEV_UNREGISTER already unlisted the dev. */ - if (op->rx_reg_dev) { - struct net_device *dev; - - dev = dev_get_by_index(sock_net(op->sk), - op->ifindex); - if (dev) { - bcm_rx_unreg(dev, op); - dev_put(dev); - } - } + if (op->rx_reg_dev) + bcm_rx_unreg(op->rx_reg_dev, op); } else can_rx_unregister(sock_net(op->sk), NULL, op->can_id, @@ -930,6 +1074,7 @@ 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; @@ -948,6 +1093,8 @@ static int bcm_tx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg, /* check the given can_id */ op = bcm_find_op(&bo->tx_ops, msg_head, ifindex); if (op) { + void *new_frames; + /* update existing BCM operation */ /* @@ -958,11 +1105,23 @@ static int bcm_tx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg, if (msg_head->nframes > op->nframes) return -E2BIG; - /* update CAN frames content */ + /* get new CAN frames content into a staging buffer before + * locking: validate and normalize the frames there so that + * bcm_can_tx() / bcm_tx_timeout_handler() never observe a + * partially updated or unvalidated frame in op->frames + */ + new_frames = kmalloc(msg_head->nframes * op->cfsiz, GFP_KERNEL); + if (!new_frames) + return -ENOMEM; + for (i = 0; i < msg_head->nframes; i++) { - cf = op->frames + op->cfsiz * i; + cf = new_frames + op->cfsiz * i; err = memcpy_from_msg((u8 *)cf, msg, op->cfsiz); + if (err < 0) { + kfree(new_frames); + return err; + } if (op->flags & CAN_FD_FRAME) { if (cf->len > 64) @@ -972,36 +1131,38 @@ static int bcm_tx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg, err = -EINVAL; } - if (err < 0) + if (err < 0) { + kfree(new_frames); return err; + } if (msg_head->flags & TX_CP_CAN_ID) { /* copy can_id into frame */ cf->can_id = msg_head->can_id; } } + + spin_lock_bh(&op->bcm_tx_lock); + + /* update CAN frames content */ + memcpy(op->frames, new_frames, msg_head->nframes * op->cfsiz); + op->flags = msg_head->flags; - /* only lock for unlikely count/nframes/currframe changes */ if (op->nframes != msg_head->nframes || - op->flags & TX_RESET_MULTI_IDX || - op->flags & SETTIMER) { - - spin_lock_bh(&op->bcm_tx_lock); + op->flags & TX_RESET_MULTI_IDX) { + /* potentially update changed nframes */ + op->nframes = msg_head->nframes; + /* restart multiple frame transmission */ + op->currframe = 0; + } - if (op->nframes != msg_head->nframes || - op->flags & TX_RESET_MULTI_IDX) { - /* potentially update changed nframes */ - op->nframes = msg_head->nframes; - /* restart multiple frame transmission */ - op->currframe = 0; - } + if (op->flags & SETTIMER) + op->count = msg_head->count; - if (op->flags & SETTIMER) - op->count = msg_head->count; + spin_unlock_bh(&op->bcm_tx_lock); - spin_unlock_bh(&op->bcm_tx_lock); - } + kfree(new_frames); } else { /* insert new BCM operation for the given can_id */ @@ -1060,6 +1221,7 @@ 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 */ @@ -1070,17 +1232,18 @@ 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))) */ if (op->flags & SETTIMER) { /* set timer values */ + spin_lock_bh(&op->bcm_tx_lock); op->ival1 = msg_head->ival1; op->ival2 = msg_head->ival2; op->kt_ival1 = bcm_timeval_to_ktime(msg_head->ival1); op->kt_ival2 = bcm_timeval_to_ktime(msg_head->ival2); + spin_unlock_bh(&op->bcm_tx_lock); /* disable an active timer due to zero values? */ if (!op->kt_ival1 && !op->kt_ival2) @@ -1093,8 +1256,12 @@ 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); + bcm_can_tx(op, NULL); if (op->flags & STARTTIMER) bcm_tx_start_timer(op); @@ -1108,6 +1275,39 @@ free_op: return err; } +static int bcm_rx_setup_rtr_check(struct bcm_msg_head *msg_head, + struct bcm_op *op, void *new_frames) +{ + struct canfd_frame *frame0 = new_frames; + + if (!(msg_head->flags & RX_RTR_FRAME)) + return 0; + + /* this frame is sent out as-is by bcm_can_tx() whenever a matching + * remote request is received, so validate its length the same way + * bcm_tx_setup() validates TX_SETUP frames before installing it + */ + if (msg_head->flags & CAN_FD_FRAME) { + if (frame0->len > 64) + return -EINVAL; + } else { + if (frame0->len > 8) + return -EINVAL; + } + + /* funny feature in RX(!)_SETUP only for RTR-mode: + * copy can_id into frame BUT without RTR-flag to + * prevent a full-load-loopback-test ... ;-] + * normalize this on the staged buffer, before it is + * ever installed into op->frames. + */ + if ((msg_head->flags & TX_CP_CAN_ID) || + frame0->can_id == op->can_id) + frame0->can_id = op->can_id & ~CAN_RTR_FLAG; + + return 0; +} + /* * bcm_rx_setup - create or update a bcm rx op (for bcm_sendmsg) */ @@ -1117,6 +1317,7 @@ static int bcm_rx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg, struct bcm_sock *bo = bcm_sk(sk); struct bcm_op *op; int do_rx_register; + int new_op = 0; int err = 0; if ((msg_head->flags & RX_FILTER_ID) || (!(msg_head->nframes))) { @@ -1142,6 +1343,8 @@ static int bcm_rx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg, /* check the given can_id */ op = bcm_find_op(&bo->rx_ops, msg_head, ifindex); if (op) { + void *new_frames = NULL; + /* update existing BCM operation */ /* @@ -1153,21 +1356,62 @@ static int bcm_rx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg, return -E2BIG; if (msg_head->nframes) { - /* update CAN frames content */ - err = memcpy_from_msg(op->frames, msg, + /* get new CAN frames content before locking */ + new_frames = kmalloc(msg_head->nframes * op->cfsiz, + GFP_KERNEL); + if (!new_frames) + return -ENOMEM; + + err = memcpy_from_msg(new_frames, msg, msg_head->nframes * op->cfsiz); - if (err < 0) + if (err < 0) { + kfree(new_frames); return err; + } - /* clear last_frames to indicate 'nothing received' */ - memset(op->last_frames, 0, msg_head->nframes * op->cfsiz); + err = bcm_rx_setup_rtr_check(msg_head, op, new_frames); + if (err < 0) { + kfree(new_frames); + return err; + } } + spin_lock_bh(&op->bcm_rx_update_lock); op->nframes = msg_head->nframes; op->flags = msg_head->flags; - /* Only an update -> do not call can_rx_register() */ - do_rx_register = 0; + if (msg_head->nframes) { + /* update CAN frames content */ + memcpy(op->frames, new_frames, + msg_head->nframes * op->cfsiz); + + /* clear last_frames to indicate 'nothing received' */ + memset(op->last_frames, 0, + msg_head->nframes * op->cfsiz); + } + + if (msg_head->flags & SETTIMER) { + op->ival1 = msg_head->ival1; + op->ival2 = msg_head->ival2; + op->kt_ival1 = bcm_timeval_to_ktime(msg_head->ival1); + op->kt_ival2 = bcm_timeval_to_ktime(msg_head->ival2); + op->kt_lastmsg = 0; + op->if_detected = 0; /* reclaim ifindex in ANYDEV mode */ + } + spin_unlock_bh(&op->bcm_rx_update_lock); + + /* free temporary frames / kfree(NULL) is safe */ + kfree(new_frames); + + /* Don't register a new CAN filter for the rx_op update unless + * a concurrent NETDEV_UNREGISTER notifier already tore down + * the previous registration. In this case the receiver needs + * to be re-registered here so that this update doesn't + * silently stop delivering frames for the given ifindex. + * Ops with ifindex = 0 (all CAN interfaces) never carry a + * tracked rx_reg_dev and stay registered as-is. + */ + do_rx_register = (ifindex && !op->rx_reg_dev) ? 1 : 0; } else { /* insert new BCM operation for the given can_id */ @@ -1176,6 +1420,7 @@ static int bcm_rx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg, return -ENOMEM; spin_lock_init(&op->bcm_tx_lock); + spin_lock_init(&op->bcm_rx_update_lock); op->can_id = msg_head->can_id; op->nframes = msg_head->nframes; op->cfsiz = CFSIZ(msg_head->flags); @@ -1209,18 +1454,17 @@ static int bcm_rx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg, if (msg_head->nframes) { err = memcpy_from_msg(op->frames, msg, msg_head->nframes * op->cfsiz); - if (err < 0) { - if (op->frames != &op->sframe) - kfree(op->frames); - if (op->last_frames != &op->last_sframe) - kfree(op->last_frames); - kfree(op); - return err; - } + if (err < 0) + goto free_op; + + err = bcm_rx_setup_rtr_check(msg_head, op, op->frames); + if (err < 0) + goto free_op; } /* 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 */ @@ -1232,40 +1476,31 @@ 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; + new_op = 1; } /* if ((op = bcm_find_op(&bo->rx_ops, msg_head->can_id, ifindex))) */ /* check flags */ if (op->flags & RX_RTR_FRAME) { - struct canfd_frame *frame0 = op->frames; - /* no timers in RTR-mode */ hrtimer_cancel(&op->thrtimer); hrtimer_cancel(&op->timer); - - /* - * funny feature in RX(!)_SETUP only for RTR-mode: - * copy can_id into frame BUT without RTR-flag to - * prevent a full-load-loopback-test ... ;-] - */ - if ((op->flags & TX_CP_CAN_ID) || - (frame0->can_id == op->can_id)) - frame0->can_id = op->can_id & ~CAN_RTR_FLAG; - } else { if (op->flags & SETTIMER) { - /* set timer value */ - op->ival1 = msg_head->ival1; - op->ival2 = msg_head->ival2; - op->kt_ival1 = bcm_timeval_to_ktime(msg_head->ival1); - op->kt_ival2 = bcm_timeval_to_ktime(msg_head->ival2); + /* set timers (locked) for newly created op */ + if (new_op) { + spin_lock_bh(&op->bcm_rx_update_lock); + op->ival1 = msg_head->ival1; + op->ival2 = msg_head->ival2; + op->kt_ival1 = bcm_timeval_to_ktime(msg_head->ival1); + op->kt_ival2 = bcm_timeval_to_ktime(msg_head->ival2); + op->kt_lastmsg = 0; + spin_unlock_bh(&op->bcm_rx_update_lock); + } /* disable an active timer due to zero value? */ if (!op->kt_ival1) @@ -1275,9 +1510,11 @@ static int bcm_rx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg, * In any case cancel the throttle timer, flush * potentially blocked msgs and reset throttle handling */ - op->kt_lastmsg = 0; hrtimer_cancel(&op->thrtimer); + + spin_lock_bh(&op->bcm_rx_update_lock); bcm_rx_thr_flush(op); + spin_unlock_bh(&op->bcm_rx_update_lock); } if ((op->flags & STARTTIMER) && op->kt_ival1) @@ -1285,7 +1522,10 @@ static int bcm_rx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg, HRTIMER_MODE_REL_SOFT); } - /* now we can register for can_ids, if we added a new bcm_op */ + /* now we can register for can_ids, if we added a new bcm_op + * or need to re-register after a NETDEV_UNREGISTER tore down + * the previous registration of an existing op + */ if (do_rx_register) { if (ifindex) { struct net_device *dev; @@ -1298,23 +1538,62 @@ static int bcm_rx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg, bcm_rx_handler, op, "bcm", sk); - op->rx_reg_dev = dev; + /* keep a tracked reference so that a later + * unregister can safely reach the device even + * if a concurrent NETDEV_UNREGISTER has + * already unlisted it by ifindex + */ + if (!err) { + op->rx_reg_dev = dev; + netdev_hold(dev, + &op->rx_reg_dev_tracker, + GFP_KERNEL); + } dev_put(dev); + } else { + /* the requested device is gone - do not + * silently succeed without registering + */ + err = -ENODEV; } - } else + } else { err = can_rx_register(sock_net(sk), NULL, op->can_id, REGMASK(op->can_id), 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); + /* newly created bcm rx op is broken -> remove it */ + if (new_op) { + bcm_remove_op(op); + return err; + } + + /* an existing op just stays unregistered. + * Cancel op->timer and (defensively) op->thrtimer. + * Other settings can't be reached until the next + * successful RX_SETUP. + */ + hrtimer_cancel(&op->timer); + hrtimer_cancel(&op->thrtimer); return err; } + + /* add a new bcm_op to the list of the rx_ops */ + if (new_op) + list_add_rcu(&op->list, &bo->rx_ops); } return msg_head->nframes * op->cfsiz + MHSIZ; + +free_op: + if (op->frames != &op->sframe) + kfree(op->frames); + if (op->last_frames != &op->last_sframe) + kfree(op->last_frames); + kfree(op); + return err; } /* @@ -1373,12 +1652,13 @@ 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 */ @@ -1394,17 +1674,38 @@ 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; @@ -1413,20 +1714,21 @@ 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: @@ -1476,6 +1778,7 @@ static int bcm_sendmsg(struct socket *sock, struct msghdr *msg, size_t size) break; } +out_release: release_sock(sk); return ret; @@ -1499,11 +1802,30 @@ static void bcm_notify(struct bcm_sock *bo, unsigned long msg, case NETDEV_UNREGISTER: lock_sock(sk); - /* remove device specific receive entries */ - list_for_each_entry(op, &bo->rx_ops, list) + /* rx_ops: remove device specific receive entries */ + list_for_each_entry(op, &bo->rx_ops, list) { if (op->rx_reg_dev == dev) bcm_rx_unreg(dev, op); + /* release an ANYDEV op's claim (see bcm_rx_handler()) + * on this now confirmed-gone interface. + */ + if (!op->ifindex) { + spin_lock_bh(&op->bcm_rx_update_lock); + if (op->if_detected == dev->ifindex) + op->if_detected = 0; + spin_unlock_bh(&op->bcm_rx_update_lock); + } + } + + /* tx_ops: stop device specific cyclic transmissions on the + * vanishing ifindex. Cancelling the timer is enough to stop + * cyclic bcm_can_tx() calls as there is no re-arming. + */ + list_for_each_entry(op, &bo->tx_ops, list) + if (op->ifindex == dev->ifindex) + hrtimer_cancel(&op->timer); + /* remove device reference, if this is our bound device */ if (bo->bound && bo->ifindex == dev->ifindex) { #if IS_ENABLED(CONFIG_PROC_FS) @@ -1512,7 +1834,12 @@ 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; } @@ -1616,8 +1943,10 @@ 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) { /* @@ -1629,16 +1958,14 @@ static int bcm_release(struct socket *sock) * Only remove subscriptions that had not * been removed due to NETDEV_UNREGISTER * in bcm_notifier() + * + * op->rx_reg_dev is a tracked reference taken + * when the subscription was registered, so it + * stays valid here even if a concurrent + * NETDEV_UNREGISTER already unlisted the device. */ - if (op->rx_reg_dev) { - struct net_device *dev; - - dev = dev_get_by_index(net, op->ifindex); - if (dev) { - bcm_rx_unreg(dev, op); - dev_put(dev); - } - } + if (op->rx_reg_dev) + bcm_rx_unreg(op->rx_reg_dev, op); } else can_rx_unregister(net, NULL, op->can_id, REGMASK(op->can_id), @@ -1648,12 +1975,14 @@ 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; } @@ -1723,7 +2052,10 @@ static int bcm_connect(struct socket *sock, struct sockaddr_unsized *uaddr, int } #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); @@ -1839,11 +2171,15 @@ 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) @@ -1861,6 +2197,8 @@ 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; } @@ -1869,6 +2207,8 @@ 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 c48b4a818297..54becaf6898f 100644 --- a/net/can/isotp.c +++ b/net/can/isotp.c @@ -152,11 +152,13 @@ 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; @@ -164,6 +166,7 @@ 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; @@ -376,6 +379,15 @@ 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))) { @@ -422,7 +434,7 @@ 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; @@ -575,6 +587,14 @@ 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; @@ -870,20 +890,36 @@ 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) { @@ -891,53 +927,83 @@ 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 */ @@ -958,13 +1024,24 @@ 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; @@ -973,9 +1050,29 @@ 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 */ @@ -1086,18 +1183,33 @@ 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; @@ -1110,13 +1222,10 @@ 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) { @@ -1132,14 +1241,21 @@ 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; @@ -1201,13 +1317,20 @@ 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); @@ -1219,36 +1342,43 @@ 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; @@ -1303,6 +1433,7 @@ static int isotp_bind(struct socket *sock, struct sockaddr_unsized *uaddr, int l if (!addr->can_ifindex) return -ENODEV; + rtnl_lock(); lock_sock(sk); if (so->bound) { @@ -1310,6 +1441,17 @@ static int isotp_bind(struct socket *sock, struct sockaddr_unsized *uaddr, int l 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; @@ -1322,14 +1464,12 @@ static int isotp_bind(struct socket *sock, struct sockaddr_unsized *uaddr, int l 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; @@ -1347,16 +1487,25 @@ static int isotp_bind(struct socket *sock, struct sockaddr_unsized *uaddr, int l 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; @@ -1559,7 +1708,7 @@ 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) { @@ -1575,10 +1724,12 @@ 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; @@ -1638,6 +1789,7 @@ 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; @@ -1664,10 +1816,14 @@ 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); |