3 files changed, 145 insertions, 84 deletions

diff --git a/net/can/bcm.c b/net/can/bcm.c
index 0bca1b9b3f70..6bc1cc4c94c5 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/spinlock.h>
 #include <net/sock.h>
 #include <net/net_namespace.h>
 
@@ -122,6 +123,7 @@ 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 */
 };
 
 struct bcm_sock {
@@ -217,7 +219,9 @@ static int bcm_proc_show(struct seq_file *m, void *v)
 	seq_printf(m, " / bound %s", bcm_proc_getifname(net, ifname, bo->ifindex));
 	seq_printf(m, " <<<\n");
 
-	list_for_each_entry(op, &bo->rx_ops, list) {
+	rcu_read_lock();
+
+	list_for_each_entry_rcu(op, &bo->rx_ops, list) {
 
 		unsigned long reduction;
 
@@ -273,6 +277,9 @@ static int bcm_proc_show(struct seq_file *m, void *v)
 		seq_printf(m, "# sent %ld\n", op->frames_abs);
 	}
 	seq_putc(m, '\n');
+
+	rcu_read_unlock();
+
 	return 0;
 }
 #endif /* CONFIG_PROC_FS */
@@ -285,13 +292,18 @@ static void bcm_can_tx(struct bcm_op *op)
 {
 	struct sk_buff *skb;
 	struct net_device *dev;
-	struct canfd_frame *cf = op->frames + op->cfsiz * op->currframe;
+	struct canfd_frame *cf;
 	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);
+
 	dev = dev_get_by_index(sock_net(op->sk), op->ifindex);
 	if (!dev) {
 		/* RFC: should this bcm_op remove itself here? */
@@ -312,6 +324,10 @@ static void bcm_can_tx(struct bcm_op *op)
 	skb->dev = dev;
 	can_skb_set_owner(skb, op->sk);
 	err = can_send(skb, 1);
+
+	/* update currframe and count under lock protection */
+	spin_lock_bh(&op->bcm_tx_lock);
+
 	if (!err)
 		op->frames_abs++;
 
@@ -320,6 +336,11 @@ static void bcm_can_tx(struct bcm_op *op)
 	/* reached last frame? */
 	if (op->currframe >= op->nframes)
 		op->currframe = 0;
+
+	if (op->count > 0)
+		op->count--;
+
+	spin_unlock_bh(&op->bcm_tx_lock);
 out:
 	dev_put(dev);
 }
@@ -430,7 +451,7 @@ static enum hrtimer_restart bcm_tx_timeout_handler(struct hrtimer *hrtimer)
 	struct bcm_msg_head msg_head;
 
 	if (op->kt_ival1 && (op->count > 0)) {
-		op->count--;
+		bcm_can_tx(op);
 		if (!op->count && (op->flags & TX_COUNTEVT)) {
 
 			/* create notification to user */
@@ -445,7 +466,6 @@ static enum hrtimer_restart bcm_tx_timeout_handler(struct hrtimer *hrtimer)
 
 			bcm_send_to_user(op, &msg_head, NULL, 0);
 		}
-		bcm_can_tx(op);
 
 	} else if (op->kt_ival2) {
 		bcm_can_tx(op);
@@ -843,7 +863,7 @@ static int bcm_delete_rx_op(struct list_head *ops, struct bcm_msg_head *mh,
 						  REGMASK(op->can_id),
 						  bcm_rx_handler, op);
 
-			list_del(&op->list);
+			list_del_rcu(&op->list);
 			bcm_remove_op(op);
 			return 1; /* done */
 		}
@@ -863,7 +883,7 @@ static int bcm_delete_tx_op(struct list_head *ops, struct bcm_msg_head *mh,
 	list_for_each_entry_safe(op, n, ops, list) {
 		if ((op->can_id == mh->can_id) && (op->ifindex == ifindex) &&
 		    (op->flags & CAN_FD_FRAME) == (mh->flags & CAN_FD_FRAME)) {
-			list_del(&op->list);
+			list_del_rcu(&op->list);
 			bcm_remove_op(op);
 			return 1; /* done */
 		}
@@ -956,6 +976,27 @@ static int bcm_tx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg,
 		}
 		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);
+
+			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;
+
+			spin_unlock_bh(&op->bcm_tx_lock);
+		}
+
 	} else {
 		/* insert new BCM operation for the given can_id */
 
@@ -963,9 +1004,14 @@ static int bcm_tx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg,
 		if (!op)
 			return -ENOMEM;
 
+		spin_lock_init(&op->bcm_tx_lock);
 		op->can_id = msg_head->can_id;
 		op->cfsiz = CFSIZ(msg_head->flags);
 		op->flags = msg_head->flags;
+		op->nframes = msg_head->nframes;
+
+		if (op->flags & SETTIMER)
+			op->count = msg_head->count;
 
 		/* create array for CAN frames and copy the data */
 		if (msg_head->nframes > 1) {
@@ -1023,22 +1069,8 @@ static int bcm_tx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg,
 
 	} /* if ((op = bcm_find_op(&bo->tx_ops, msg_head->can_id, ifindex))) */
 
-	if (op->nframes != msg_head->nframes) {
-		op->nframes   = msg_head->nframes;
-		/* start multiple frame transmission with index 0 */
-		op->currframe = 0;
-	}
-
-	/* check flags */
-
-	if (op->flags & TX_RESET_MULTI_IDX) {
-		/* start multiple frame transmission with index 0 */
-		op->currframe = 0;
-	}
-
 	if (op->flags & SETTIMER) {
 		/* set timer values */
-		op->count = msg_head->count;
 		op->ival1 = msg_head->ival1;
 		op->ival2 = msg_head->ival2;
 		op->kt_ival1 = bcm_timeval_to_ktime(msg_head->ival1);
@@ -1055,11 +1087,8 @@ static int bcm_tx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg,
 		op->flags |= TX_ANNOUNCE;
 	}
 
-	if (op->flags & TX_ANNOUNCE) {
+	if (op->flags & TX_ANNOUNCE)
 		bcm_can_tx(op);
-		if (op->count)
-			op->count--;
-	}
 
 	if (op->flags & STARTTIMER)
 		bcm_tx_start_timer(op);
@@ -1272,7 +1301,7 @@ 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(&op->list);
+			list_del_rcu(&op->list);
 			bcm_remove_op(op);
 			return err;
 		}
diff --git a/net/can/gw.c b/net/can/gw.c
index ef93293c1fae..55eccb1c7620 100644
--- a/net/can/gw.c
+++ b/net/can/gw.c
@@ -130,7 +130,7 @@ struct cgw_job {
 	u32 handled_frames;
 	u32 dropped_frames;
 	u32 deleted_frames;
-	struct cf_mod mod;
+	struct cf_mod __rcu *cf_mod;
 	union {
 		/* CAN frame data source */
 		struct net_device *dev;
@@ -459,6 +459,7 @@ static void can_can_gw_rcv(struct sk_buff *skb, void *data)
 	struct cgw_job *gwj = (struct cgw_job *)data;
 	struct canfd_frame *cf;
 	struct sk_buff *nskb;
+	struct cf_mod *mod;
 	int modidx = 0;
 
 	/* process strictly Classic CAN or CAN FD frames */
@@ -506,7 +507,8 @@ static void can_can_gw_rcv(struct sk_buff *skb, void *data)
 	 * When there is at least one modification function activated,
 	 * we need to copy the skb as we want to modify skb->data.
 	 */
-	if (gwj->mod.modfunc[0])
+	mod = rcu_dereference(gwj->cf_mod);
+	if (mod->modfunc[0])
 		nskb = skb_copy(skb, GFP_ATOMIC);
 	else
 		nskb = skb_clone(skb, GFP_ATOMIC);
@@ -529,8 +531,8 @@ static void can_can_gw_rcv(struct sk_buff *skb, void *data)
 	cf = (struct canfd_frame *)nskb->data;
 
 	/* perform preprocessed modification functions if there are any */
-	while (modidx < MAX_MODFUNCTIONS && gwj->mod.modfunc[modidx])
-		(*gwj->mod.modfunc[modidx++])(cf, &gwj->mod);
+	while (modidx < MAX_MODFUNCTIONS && mod->modfunc[modidx])
+		(*mod->modfunc[modidx++])(cf, mod);
 
 	/* Has the CAN frame been modified? */
 	if (modidx) {
@@ -546,11 +548,11 @@ static void can_can_gw_rcv(struct sk_buff *skb, void *data)
 		}
 
 		/* check for checksum updates */
-		if (gwj->mod.csumfunc.crc8)
-			(*gwj->mod.csumfunc.crc8)(cf, &gwj->mod.csum.crc8);
+		if (mod->csumfunc.crc8)
+			(*mod->csumfunc.crc8)(cf, &mod->csum.crc8);
 
-		if (gwj->mod.csumfunc.xor)
-			(*gwj->mod.csumfunc.xor)(cf, &gwj->mod.csum.xor);
+		if (mod->csumfunc.xor)
+			(*mod->csumfunc.xor)(cf, &mod->csum.xor);
 	}
 
 	/* clear the skb timestamp if not configured the other way */
@@ -581,9 +583,20 @@ static void cgw_job_free_rcu(struct rcu_head *rcu_head)
 {
 	struct cgw_job *gwj = container_of(rcu_head, struct cgw_job, rcu);
 
+	/* cgw_job::cf_mod is always accessed from the same cgw_job object within
+	 * the same RCU read section. Once cgw_job is scheduled for removal,
+	 * cf_mod can also be removed without mandating an additional grace period.
+	 */
+	kfree(rcu_access_pointer(gwj->cf_mod));
 	kmem_cache_free(cgw_cache, gwj);
 }
 
+/* Return cgw_job::cf_mod with RTNL protected section */
+static struct cf_mod *cgw_job_cf_mod(struct cgw_job *gwj)
+{
+	return rcu_dereference_protected(gwj->cf_mod, rtnl_is_locked());
+}
+
 static int cgw_notifier(struct notifier_block *nb,
 			unsigned long msg, void *ptr)
 {
@@ -616,6 +629,7 @@ static int cgw_put_job(struct sk_buff *skb, struct cgw_job *gwj, int type,
 {
 	struct rtcanmsg *rtcan;
 	struct nlmsghdr *nlh;
+	struct cf_mod *mod;
 
 	nlh = nlmsg_put(skb, pid, seq, type, sizeof(*rtcan), flags);
 	if (!nlh)
@@ -650,82 +664,83 @@ static int cgw_put_job(struct sk_buff *skb, struct cgw_job *gwj, int type,
 			goto cancel;
 	}
 
+	mod = cgw_job_cf_mod(gwj);
 	if (gwj->flags & CGW_FLAGS_CAN_FD) {
 		struct cgw_fdframe_mod mb;
 
-		if (gwj->mod.modtype.and) {
-			memcpy(&mb.cf, &gwj->mod.modframe.and, sizeof(mb.cf));
-			mb.modtype = gwj->mod.modtype.and;
+		if (mod->modtype.and) {
+			memcpy(&mb.cf, &mod->modframe.and, sizeof(mb.cf));
+			mb.modtype = mod->modtype.and;
 			if (nla_put(skb, CGW_FDMOD_AND, sizeof(mb), &mb) < 0)
 				goto cancel;
 		}
 
-		if (gwj->mod.modtype.or) {
-			memcpy(&mb.cf, &gwj->mod.modframe.or, sizeof(mb.cf));
-			mb.modtype = gwj->mod.modtype.or;
+		if (mod->modtype.or) {
+			memcpy(&mb.cf, &mod->modframe.or, sizeof(mb.cf));
+			mb.modtype = mod->modtype.or;
 			if (nla_put(skb, CGW_FDMOD_OR, sizeof(mb), &mb) < 0)
 				goto cancel;
 		}
 
-		if (gwj->mod.modtype.xor) {
-			memcpy(&mb.cf, &gwj->mod.modframe.xor, sizeof(mb.cf));
-			mb.modtype = gwj->mod.modtype.xor;
+		if (mod->modtype.xor) {
+			memcpy(&mb.cf, &mod->modframe.xor, sizeof(mb.cf));
+			mb.modtype = mod->modtype.xor;
 			if (nla_put(skb, CGW_FDMOD_XOR, sizeof(mb), &mb) < 0)
 				goto cancel;
 		}
 
-		if (gwj->mod.modtype.set) {
-			memcpy(&mb.cf, &gwj->mod.modframe.set, sizeof(mb.cf));
-			mb.modtype = gwj->mod.modtype.set;
+		if (mod->modtype.set) {
+			memcpy(&mb.cf, &mod->modframe.set, sizeof(mb.cf));
+			mb.modtype = mod->modtype.set;
 			if (nla_put(skb, CGW_FDMOD_SET, sizeof(mb), &mb) < 0)
 				goto cancel;
 		}
 	} else {
 		struct cgw_frame_mod mb;
 
-		if (gwj->mod.modtype.and) {
-			memcpy(&mb.cf, &gwj->mod.modframe.and, sizeof(mb.cf));
-			mb.modtype = gwj->mod.modtype.and;
+		if (mod->modtype.and) {
+			memcpy(&mb.cf, &mod->modframe.and, sizeof(mb.cf));
+			mb.modtype = mod->modtype.and;
 			if (nla_put(skb, CGW_MOD_AND, sizeof(mb), &mb) < 0)
 				goto cancel;
 		}
 
-		if (gwj->mod.modtype.or) {
-			memcpy(&mb.cf, &gwj->mod.modframe.or, sizeof(mb.cf));
-			mb.modtype = gwj->mod.modtype.or;
+		if (mod->modtype.or) {
+			memcpy(&mb.cf, &mod->modframe.or, sizeof(mb.cf));
+			mb.modtype = mod->modtype.or;
 			if (nla_put(skb, CGW_MOD_OR, sizeof(mb), &mb) < 0)
 				goto cancel;
 		}
 
-		if (gwj->mod.modtype.xor) {
-			memcpy(&mb.cf, &gwj->mod.modframe.xor, sizeof(mb.cf));
-			mb.modtype = gwj->mod.modtype.xor;
+		if (mod->modtype.xor) {
+			memcpy(&mb.cf, &mod->modframe.xor, sizeof(mb.cf));
+			mb.modtype = mod->modtype.xor;
 			if (nla_put(skb, CGW_MOD_XOR, sizeof(mb), &mb) < 0)
 				goto cancel;
 		}
 
-		if (gwj->mod.modtype.set) {
-			memcpy(&mb.cf, &gwj->mod.modframe.set, sizeof(mb.cf));
-			mb.modtype = gwj->mod.modtype.set;
+		if (mod->modtype.set) {
+			memcpy(&mb.cf, &mod->modframe.set, sizeof(mb.cf));
+			mb.modtype = mod->modtype.set;
 			if (nla_put(skb, CGW_MOD_SET, sizeof(mb), &mb) < 0)
 				goto cancel;
 		}
 	}
 
-	if (gwj->mod.uid) {
-		if (nla_put_u32(skb, CGW_MOD_UID, gwj->mod.uid) < 0)
+	if (mod->uid) {
+		if (nla_put_u32(skb, CGW_MOD_UID, mod->uid) < 0)
 			goto cancel;
 	}
 
-	if (gwj->mod.csumfunc.crc8) {
+	if (mod->csumfunc.crc8) {
 		if (nla_put(skb, CGW_CS_CRC8, CGW_CS_CRC8_LEN,
-			    &gwj->mod.csum.crc8) < 0)
+			    &mod->csum.crc8) < 0)
 			goto cancel;
 	}
 
-	if (gwj->mod.csumfunc.xor) {
+	if (mod->csumfunc.xor) {
 		if (nla_put(skb, CGW_CS_XOR, CGW_CS_XOR_LEN,
-			    &gwj->mod.csum.xor) < 0)
+			    &mod->csum.xor) < 0)
 			goto cancel;
 	}
 
@@ -1059,7 +1074,7 @@ static int cgw_create_job(struct sk_buff *skb,  struct nlmsghdr *nlh,
 	struct net *net = sock_net(skb->sk);
 	struct rtcanmsg *r;
 	struct cgw_job *gwj;
-	struct cf_mod mod;
+	struct cf_mod *mod;
 	struct can_can_gw ccgw;
 	u8 limhops = 0;
 	int err = 0;
@@ -1078,37 +1093,48 @@ static int cgw_create_job(struct sk_buff *skb,  struct nlmsghdr *nlh,
 	if (r->gwtype != CGW_TYPE_CAN_CAN)
 		return -EINVAL;
 
-	err = cgw_parse_attr(nlh, &mod, CGW_TYPE_CAN_CAN, &ccgw, &limhops);
+	mod = kmalloc(sizeof(*mod), GFP_KERNEL);
+	if (!mod)
+		return -ENOMEM;
+
+	err = cgw_parse_attr(nlh, mod, CGW_TYPE_CAN_CAN, &ccgw, &limhops);
 	if (err < 0)
-		return err;
+		goto out_free_cf;
 
-	if (mod.uid) {
+	if (mod->uid) {
 		ASSERT_RTNL();
 
 		/* check for updating an existing job with identical uid */
 		hlist_for_each_entry(gwj, &net->can.cgw_list, list) {
-			if (gwj->mod.uid != mod.uid)
+			struct cf_mod *old_cf;
+
+			old_cf = cgw_job_cf_mod(gwj);
+			if (old_cf->uid != mod->uid)
 				continue;
 
 			/* interfaces & filters must be identical */
-			if (memcmp(&gwj->ccgw, &ccgw, sizeof(ccgw)))
-				return -EINVAL;
+			if (memcmp(&gwj->ccgw, &ccgw, sizeof(ccgw))) {
+				err = -EINVAL;
+				goto out_free_cf;
+			}
 
-			/* update modifications with disabled softirq & quit */
-			local_bh_disable();
-			memcpy(&gwj->mod, &mod, sizeof(mod));
-			local_bh_enable();
+			rcu_assign_pointer(gwj->cf_mod, mod);
+			kfree_rcu_mightsleep(old_cf);
 			return 0;
 		}
 	}
 
 	/* ifindex == 0 is not allowed for job creation */
-	if (!ccgw.src_idx || !ccgw.dst_idx)
-		return -ENODEV;
+	if (!ccgw.src_idx || !ccgw.dst_idx) {
+		err = -ENODEV;
+		goto out_free_cf;
+	}
 
 	gwj = kmem_cache_alloc(cgw_cache, GFP_KERNEL);
-	if (!gwj)
-		return -ENOMEM;
+	if (!gwj) {
+		err = -ENOMEM;
+		goto out_free_cf;
+	}
 
 	gwj->handled_frames = 0;
 	gwj->dropped_frames = 0;
@@ -1118,7 +1144,7 @@ static int cgw_create_job(struct sk_buff *skb,  struct nlmsghdr *nlh,
 	gwj->limit_hops = limhops;
 
 	/* insert already parsed information */
-	memcpy(&gwj->mod, &mod, sizeof(mod));
+	RCU_INIT_POINTER(gwj->cf_mod, mod);
 	memcpy(&gwj->ccgw, &ccgw, sizeof(ccgw));
 
 	err = -ENODEV;
@@ -1152,9 +1178,11 @@ static int cgw_create_job(struct sk_buff *skb,  struct nlmsghdr *nlh,
 	if (!err)
 		hlist_add_head_rcu(&gwj->list, &net->can.cgw_list);
 out:
-	if (err)
+	if (err) {
 		kmem_cache_free(cgw_cache, gwj);
-
+out_free_cf:
+		kfree(mod);
+	}
 	return err;
 }
 
@@ -1214,19 +1242,22 @@ static int cgw_remove_job(struct sk_buff *skb, struct nlmsghdr *nlh,
 
 	/* remove only the first matching entry */
 	hlist_for_each_entry_safe(gwj, nx, &net->can.cgw_list, list) {
+		struct cf_mod *cf_mod;
+
 		if (gwj->flags != r->flags)
 			continue;
 
 		if (gwj->limit_hops != limhops)
 			continue;
 
+		cf_mod = cgw_job_cf_mod(gwj);
 		/* we have a match when uid is enabled and identical */
-		if (gwj->mod.uid || mod.uid) {
-			if (gwj->mod.uid != mod.uid)
+		if (cf_mod->uid || mod.uid) {
+			if (cf_mod->uid != mod.uid)
 				continue;
 		} else {
 			/* no uid => check for identical modifications */
-			if (memcmp(&gwj->mod, &mod, sizeof(mod)))
+			if (memcmp(cf_mod, &mod, sizeof(mod)))
 				continue;
 		}
 
diff --git a/net/can/j1939/socket.c b/net/can/j1939/socket.c
index 17226b2341d0..6fefe7a68761 100644
--- a/net/can/j1939/socket.c
+++ b/net/can/j1939/socket.c
@@ -655,6 +655,7 @@ static int j1939_sk_release(struct socket *sock)
 	sock->sk = NULL;
 
 	release_sock(sk);
+	sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
 	sock_put(sk);
 
 	return 0;