1 files changed, 84 insertions, 31 deletions

diff --git a/net/bluetooth/6lowpan.c b/net/bluetooth/6lowpan.c
index 50cfec8ccac4..2c21ae8abadc 100644
--- a/net/bluetooth/6lowpan.c
+++ b/net/bluetooth/6lowpan.c
@@ -13,6 +13,7 @@
 #include <net/ipv6.h>
 #include <net/ip6_route.h>
 #include <net/addrconf.h>
+#include <net/netdev_lock.h>
 #include <net/pkt_sched.h>
 
 #include <net/bluetooth/bluetooth.h>
@@ -52,6 +53,11 @@ static bool enable_6lowpan;
 static struct l2cap_chan *listen_chan;
 static DEFINE_MUTEX(set_lock);
 
+enum {
+	LOWPAN_PEER_CLOSING,
+	LOWPAN_PEER_MAXBITS
+};
+
 struct lowpan_peer {
 	struct list_head list;
 	struct rcu_head rcu;
@@ -60,6 +66,8 @@ struct lowpan_peer {
 	/* peer addresses in various formats */
 	unsigned char lladdr[ETH_ALEN];
 	struct in6_addr peer_addr;
+
+	DECLARE_BITMAP(flags, LOWPAN_PEER_MAXBITS);
 };
 
 struct lowpan_btle_dev {
@@ -288,6 +296,7 @@ static int recv_pkt(struct sk_buff *skb, struct net_device *dev,
 		local_skb->pkt_type = PACKET_HOST;
 		local_skb->dev = dev;
 
+		skb_reset_mac_header(local_skb);
 		skb_set_transport_header(local_skb, sizeof(struct ipv6hdr));
 
 		if (give_skb_to_upper(local_skb, dev) != NET_RX_SUCCESS) {
@@ -443,7 +452,7 @@ static int send_pkt(struct l2cap_chan *chan, struct sk_buff *skb,
 	memset(&msg, 0, sizeof(msg));
 	iov_iter_kvec(&msg.msg_iter, ITER_SOURCE, &iv, 1, skb->len);
 
-	err = l2cap_chan_send(chan, &msg, skb->len);
+	err = l2cap_chan_send(chan, &msg, skb->len, NULL);
 	if (err > 0) {
 		netdev->stats.tx_bytes += err;
 		netdev->stats.tx_packets++;
@@ -825,11 +834,16 @@ static struct sk_buff *chan_alloc_skb_cb(struct l2cap_chan *chan,
 					 unsigned long hdr_len,
 					 unsigned long len, int nb)
 {
+	struct sk_buff *skb;
+
 	/* Note that we must allocate using GFP_ATOMIC here as
 	 * this function is called originally from netdev hard xmit
 	 * function in atomic context.
 	 */
-	return bt_skb_alloc(hdr_len + len, GFP_ATOMIC);
+	skb = bt_skb_alloc(hdr_len + len, GFP_ATOMIC);
+	if (!skb)
+		return ERR_PTR(-ENOMEM);
+	return skb;
 }
 
 static void chan_suspend_cb(struct l2cap_chan *chan)
@@ -913,7 +927,9 @@ static int bt_6lowpan_disconnect(struct l2cap_conn *conn, u8 dst_type)
 
 	BT_DBG("peer %p chan %p", peer, peer->chan);
 
+	l2cap_chan_lock(peer->chan);
 	l2cap_chan_close(peer->chan, ENOENT);
+	l2cap_chan_unlock(peer->chan);
 
 	return 0;
 }
@@ -950,10 +966,11 @@ static struct l2cap_chan *bt_6lowpan_listen(void)
 }
 
 static int get_l2cap_conn(char *buf, bdaddr_t *addr, u8 *addr_type,
-			  struct l2cap_conn **conn)
+			  struct l2cap_conn **conn, bool disconnect)
 {
 	struct hci_conn *hcon;
 	struct hci_dev *hdev;
+	int le_addr_type;
 	int n;
 
 	n = sscanf(buf, "%hhx:%hhx:%hhx:%hhx:%hhx:%hhx %hhu",
@@ -964,13 +981,32 @@ static int get_l2cap_conn(char *buf, bdaddr_t *addr, u8 *addr_type,
 	if (n < 7)
 		return -EINVAL;
 
+	if (disconnect) {
+		/* The "disconnect" debugfs command has used different address
+		 * type constants than "connect" since 2015. Let's retain that
+		 * for now even though it's obviously buggy...
+		 */
+		*addr_type += 1;
+	}
+
+	switch (*addr_type) {
+	case BDADDR_LE_PUBLIC:
+		le_addr_type = ADDR_LE_DEV_PUBLIC;
+		break;
+	case BDADDR_LE_RANDOM:
+		le_addr_type = ADDR_LE_DEV_RANDOM;
+		break;
+	default:
+		return -EINVAL;
+	}
+
 	/* The LE_PUBLIC address type is ignored because of BDADDR_ANY */
 	hdev = hci_get_route(addr, BDADDR_ANY, BDADDR_LE_PUBLIC);
 	if (!hdev)
 		return -ENOENT;
 
 	hci_dev_lock(hdev);
-	hcon = hci_conn_hash_lookup_le(hdev, addr, *addr_type);
+	hcon = hci_conn_hash_lookup_le(hdev, addr, le_addr_type);
 	hci_dev_unlock(hdev);
 	hci_dev_put(hdev);
 
@@ -987,41 +1023,52 @@ static int get_l2cap_conn(char *buf, bdaddr_t *addr, u8 *addr_type,
 static void disconnect_all_peers(void)
 {
 	struct lowpan_btle_dev *entry;
-	struct lowpan_peer *peer, *tmp_peer, *new_peer;
-	struct list_head peers;
-
-	INIT_LIST_HEAD(&peers);
+	struct lowpan_peer *peer;
+	int nchans;
 
-	/* We make a separate list of peers as the close_cb() will
-	 * modify the device peers list so it is better not to mess
-	 * with the same list at the same time.
+	/* l2cap_chan_close() cannot be called from RCU, and lock ordering
+	 * chan->lock > devices_lock prevents taking write side lock, so copy
+	 * then close.
 	 */
 
 	rcu_read_lock();
+	list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list)
+		list_for_each_entry_rcu(peer, &entry->peers, list)
+			clear_bit(LOWPAN_PEER_CLOSING, peer->flags);
+	rcu_read_unlock();
 
-	list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
-		list_for_each_entry_rcu(peer, &entry->peers, list) {
-			new_peer = kmalloc(sizeof(*new_peer), GFP_ATOMIC);
-			if (!new_peer)
-				break;
+	do {
+		struct l2cap_chan *chans[32];
+		int i;
 
-			new_peer->chan = peer->chan;
-			INIT_LIST_HEAD(&new_peer->list);
+		nchans = 0;
 
-			list_add(&new_peer->list, &peers);
-		}
-	}
+		spin_lock(&devices_lock);
 
-	rcu_read_unlock();
+		list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
+			list_for_each_entry_rcu(peer, &entry->peers, list) {
+				if (test_and_set_bit(LOWPAN_PEER_CLOSING,
+						     peer->flags))
+					continue;
 
-	spin_lock(&devices_lock);
-	list_for_each_entry_safe(peer, tmp_peer, &peers, list) {
-		l2cap_chan_close(peer->chan, ENOENT);
+				l2cap_chan_hold(peer->chan);
+				chans[nchans++] = peer->chan;
 
-		list_del_rcu(&peer->list);
-		kfree_rcu(peer, rcu);
-	}
-	spin_unlock(&devices_lock);
+				if (nchans >= ARRAY_SIZE(chans))
+					goto done;
+			}
+		}
+
+done:
+		spin_unlock(&devices_lock);
+
+		for (i = 0; i < nchans; ++i) {
+			l2cap_chan_lock(chans[i]);
+			l2cap_chan_close(chans[i], ENOENT);
+			l2cap_chan_unlock(chans[i]);
+			l2cap_chan_put(chans[i]);
+		}
+	} while (nchans);
 }
 
 struct set_enable {
@@ -1044,7 +1091,9 @@ static void do_enable_set(struct work_struct *work)
 
 	mutex_lock(&set_lock);
 	if (listen_chan) {
+		l2cap_chan_lock(listen_chan);
 		l2cap_chan_close(listen_chan, 0);
+		l2cap_chan_unlock(listen_chan);
 		l2cap_chan_put(listen_chan);
 	}
 
@@ -1097,13 +1146,15 @@ static ssize_t lowpan_control_write(struct file *fp,
 	buf[buf_size] = '\0';
 
 	if (memcmp(buf, "connect ", 8) == 0) {
-		ret = get_l2cap_conn(&buf[8], &addr, &addr_type, &conn);
+		ret = get_l2cap_conn(&buf[8], &addr, &addr_type, &conn, false);
 		if (ret == -EINVAL)
 			return ret;
 
 		mutex_lock(&set_lock);
 		if (listen_chan) {
+			l2cap_chan_lock(listen_chan);
 			l2cap_chan_close(listen_chan, 0);
+			l2cap_chan_unlock(listen_chan);
 			l2cap_chan_put(listen_chan);
 			listen_chan = NULL;
 		}
@@ -1134,7 +1185,7 @@ static ssize_t lowpan_control_write(struct file *fp,
 	}
 
 	if (memcmp(buf, "disconnect ", 11) == 0) {
-		ret = get_l2cap_conn(&buf[11], &addr, &addr_type, &conn);
+		ret = get_l2cap_conn(&buf[11], &addr, &addr_type, &conn, true);
 		if (ret < 0)
 			return ret;
 
@@ -1265,7 +1316,9 @@ static void __exit bt_6lowpan_exit(void)
 	debugfs_remove(lowpan_control_debugfs);
 
 	if (listen_chan) {
+		l2cap_chan_lock(listen_chan);
 		l2cap_chan_close(listen_chan, 0);
+		l2cap_chan_unlock(listen_chan);
 		l2cap_chan_put(listen_chan);
 	}