1 files changed, 174 insertions, 30 deletions

diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index 7c7e9321f1ea..24bee07ee4ce 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -571,7 +571,7 @@ void l2cap_chan_del(struct l2cap_chan *chan, int err)
 		chan->conn = NULL;
 
 		if (chan->chan_type != L2CAP_CHAN_CONN_FIX_A2MP)
-			hci_conn_put(conn->hcon);
+			hci_conn_drop(conn->hcon);
 
 		if (mgr && mgr->bredr_chan == chan)
 			mgr->bredr_chan = NULL;
@@ -1446,6 +1446,89 @@ static void l2cap_info_timeout(struct work_struct *work)
 	l2cap_conn_start(conn);
 }
 
+/*
+ * l2cap_user
+ * External modules can register l2cap_user objects on l2cap_conn. The ->probe
+ * callback is called during registration. The ->remove callback is called
+ * during unregistration.
+ * An l2cap_user object can either be explicitly unregistered or when the
+ * underlying l2cap_conn object is deleted. This guarantees that l2cap->hcon,
+ * l2cap->hchan, .. are valid as long as the remove callback hasn't been called.
+ * External modules must own a reference to the l2cap_conn object if they intend
+ * to call l2cap_unregister_user(). The l2cap_conn object might get destroyed at
+ * any time if they don't.
+ */
+
+int l2cap_register_user(struct l2cap_conn *conn, struct l2cap_user *user)
+{
+	struct hci_dev *hdev = conn->hcon->hdev;
+	int ret;
+
+	/* We need to check whether l2cap_conn is registered. If it is not, we
+	 * must not register the l2cap_user. l2cap_conn_del() is unregisters
+	 * l2cap_conn objects, but doesn't provide its own locking. Instead, it
+	 * relies on the parent hci_conn object to be locked. This itself relies
+	 * on the hci_dev object to be locked. So we must lock the hci device
+	 * here, too. */
+
+	hci_dev_lock(hdev);
+
+	if (user->list.next || user->list.prev) {
+		ret = -EINVAL;
+		goto out_unlock;
+	}
+
+	/* conn->hchan is NULL after l2cap_conn_del() was called */
+	if (!conn->hchan) {
+		ret = -ENODEV;
+		goto out_unlock;
+	}
+
+	ret = user->probe(conn, user);
+	if (ret)
+		goto out_unlock;
+
+	list_add(&user->list, &conn->users);
+	ret = 0;
+
+out_unlock:
+	hci_dev_unlock(hdev);
+	return ret;
+}
+EXPORT_SYMBOL(l2cap_register_user);
+
+void l2cap_unregister_user(struct l2cap_conn *conn, struct l2cap_user *user)
+{
+	struct hci_dev *hdev = conn->hcon->hdev;
+
+	hci_dev_lock(hdev);
+
+	if (!user->list.next || !user->list.prev)
+		goto out_unlock;
+
+	list_del(&user->list);
+	user->list.next = NULL;
+	user->list.prev = NULL;
+	user->remove(conn, user);
+
+out_unlock:
+	hci_dev_unlock(hdev);
+}
+EXPORT_SYMBOL(l2cap_unregister_user);
+
+static void l2cap_unregister_all_users(struct l2cap_conn *conn)
+{
+	struct l2cap_user *user;
+
+	while (!list_empty(&conn->users)) {
+		user = list_first_entry(&conn->users, struct l2cap_user, list);
+		list_del(&user->list);
+		user->list.next = NULL;
+		user->list.prev = NULL;
+		user->remove(conn, user);
+	}
+}
+
 static void l2cap_conn_del(struct hci_conn *hcon, int err)
 {
 	struct l2cap_conn *conn = hcon->l2cap_data;
@@ -1458,6 +1541,8 @@ static void l2cap_conn_del(struct hci_conn *hcon, int err)
 
 	kfree_skb(conn->rx_skb);
 
+	l2cap_unregister_all_users(conn);
+
 	mutex_lock(&conn->chan_lock);
 
 	/* Kill channels */
@@ -1486,7 +1571,8 @@ static void l2cap_conn_del(struct hci_conn *hcon, int err)
 	}
 
 	hcon->l2cap_data = NULL;
-	kfree(conn);
+	conn->hchan = NULL;
+	l2cap_conn_put(conn);
 }
 
 static void security_timeout(struct work_struct *work)
@@ -1502,12 +1588,12 @@ static void security_timeout(struct work_struct *work)
 	}
 }
 
-static struct l2cap_conn *l2cap_conn_add(struct hci_conn *hcon, u8 status)
+static struct l2cap_conn *l2cap_conn_add(struct hci_conn *hcon)
 {
 	struct l2cap_conn *conn = hcon->l2cap_data;
 	struct hci_chan *hchan;
 
-	if (conn || status)
+	if (conn)
 		return conn;
 
 	hchan = hci_chan_create(hcon);
@@ -1520,8 +1606,10 @@ static struct l2cap_conn *l2cap_conn_add(struct hci_conn *hcon, u8 status)
 		return NULL;
 	}
 
+	kref_init(&conn->ref);
 	hcon->l2cap_data = conn;
 	conn->hcon = hcon;
+	hci_conn_get(conn->hcon);
 	conn->hchan = hchan;
 
 	BT_DBG("hcon %p conn %p hchan %p", hcon, conn, hchan);
@@ -1547,6 +1635,7 @@ static struct l2cap_conn *l2cap_conn_add(struct hci_conn *hcon, u8 status)
 	mutex_init(&conn->chan_lock);
 
 	INIT_LIST_HEAD(&conn->chan_l);
+	INIT_LIST_HEAD(&conn->users);
 
 	if (hcon->type == LE_LINK)
 		INIT_DELAYED_WORK(&conn->security_timer, security_timeout);
@@ -1558,6 +1647,26 @@ static struct l2cap_conn *l2cap_conn_add(struct hci_conn *hcon, u8 status)
 	return conn;
 }
 
+static void l2cap_conn_free(struct kref *ref)
+{
+	struct l2cap_conn *conn = container_of(ref, struct l2cap_conn, ref);
+
+	hci_conn_put(conn->hcon);
+	kfree(conn);
+}
+
+void l2cap_conn_get(struct l2cap_conn *conn)
+{
+	kref_get(&conn->ref);
+}
+EXPORT_SYMBOL(l2cap_conn_get);
+
+void l2cap_conn_put(struct l2cap_conn *conn)
+{
+	kref_put(&conn->ref, l2cap_conn_free);
+}
+EXPORT_SYMBOL(l2cap_conn_put);
+
 /* ---- Socket interface ---- */
 
 /* Find socket with psm and source / destination bdaddr.
@@ -1695,9 +1804,9 @@ int l2cap_chan_connect(struct l2cap_chan *chan, __le16 psm, u16 cid,
 		goto done;
 	}
 
-	conn = l2cap_conn_add(hcon, 0);
+	conn = l2cap_conn_add(hcon);
 	if (!conn) {
-		hci_conn_put(hcon);
+		hci_conn_drop(hcon);
 		err = -ENOMEM;
 		goto done;
 	}
@@ -1707,7 +1816,7 @@ int l2cap_chan_connect(struct l2cap_chan *chan, __le16 psm, u16 cid,
 
 		if (!list_empty(&conn->chan_l)) {
 			err = -EBUSY;
-			hci_conn_put(hcon);
+			hci_conn_drop(hcon);
 		}
 
 		if (err)
@@ -3568,10 +3677,14 @@ static void l2cap_conf_rfc_get(struct l2cap_chan *chan, void *rsp, int len)
 }
 
 static inline int l2cap_command_rej(struct l2cap_conn *conn,
-				    struct l2cap_cmd_hdr *cmd, u8 *data)
+				    struct l2cap_cmd_hdr *cmd, u16 cmd_len,
+				    u8 *data)
 {
 	struct l2cap_cmd_rej_unk *rej = (struct l2cap_cmd_rej_unk *) data;
 
+	if (cmd_len < sizeof(*rej))
+		return -EPROTO;
+
 	if (rej->reason != L2CAP_REJ_NOT_UNDERSTOOD)
 		return 0;
 
@@ -3720,11 +3833,14 @@ sendresp:
 }
 
 static int l2cap_connect_req(struct l2cap_conn *conn,
-			     struct l2cap_cmd_hdr *cmd, u8 *data)
+			     struct l2cap_cmd_hdr *cmd, u16 cmd_len, u8 *data)
 {
 	struct hci_dev *hdev = conn->hcon->hdev;
 	struct hci_conn *hcon = conn->hcon;
 
+	if (cmd_len < sizeof(struct l2cap_conn_req))
+		return -EPROTO;
+
 	hci_dev_lock(hdev);
 	if (test_bit(HCI_MGMT, &hdev->dev_flags) &&
 	    !test_and_set_bit(HCI_CONN_MGMT_CONNECTED, &hcon->flags))
@@ -3738,7 +3854,8 @@ static int l2cap_connect_req(struct l2cap_conn *conn,
 }
 
 static int l2cap_connect_create_rsp(struct l2cap_conn *conn,
-				    struct l2cap_cmd_hdr *cmd, u8 *data)
+				    struct l2cap_cmd_hdr *cmd, u16 cmd_len,
+				    u8 *data)
 {
 	struct l2cap_conn_rsp *rsp = (struct l2cap_conn_rsp *) data;
 	u16 scid, dcid, result, status;
@@ -3746,6 +3863,9 @@ static int l2cap_connect_create_rsp(struct l2cap_conn *conn,
 	u8 req[128];
 	int err;
 
+	if (cmd_len < sizeof(*rsp))
+		return -EPROTO;
+
 	scid   = __le16_to_cpu(rsp->scid);
 	dcid   = __le16_to_cpu(rsp->dcid);
 	result = __le16_to_cpu(rsp->result);
@@ -3843,6 +3963,9 @@ static inline int l2cap_config_req(struct l2cap_conn *conn,
 	struct l2cap_chan *chan;
 	int len, err = 0;
 
+	if (cmd_len < sizeof(*req))
+		return -EPROTO;
+
 	dcid  = __le16_to_cpu(req->dcid);
 	flags = __le16_to_cpu(req->flags);
 
@@ -3866,7 +3989,7 @@ static inline int l2cap_config_req(struct l2cap_conn *conn,
 
 	/* Reject if config buffer is too small. */
 	len = cmd_len - sizeof(*req);
-	if (len < 0 || chan->conf_len + len > sizeof(chan->conf_req)) {
+	if (chan->conf_len + len > sizeof(chan->conf_req)) {
 		l2cap_send_cmd(conn, cmd->ident, L2CAP_CONF_RSP,
 			       l2cap_build_conf_rsp(chan, rsp,
 			       L2CAP_CONF_REJECT, flags), rsp);
@@ -3944,14 +4067,18 @@ unlock:
 }
 
 static inline int l2cap_config_rsp(struct l2cap_conn *conn,
-				   struct l2cap_cmd_hdr *cmd, u8 *data)
+				   struct l2cap_cmd_hdr *cmd, u16 cmd_len,
+				   u8 *data)
 {
 	struct l2cap_conf_rsp *rsp = (struct l2cap_conf_rsp *)data;
 	u16 scid, flags, result;
 	struct l2cap_chan *chan;
-	int len = le16_to_cpu(cmd->len) - sizeof(*rsp);
+	int len = cmd_len - sizeof(*rsp);
 	int err = 0;
 
+	if (cmd_len < sizeof(*rsp))
+		return -EPROTO;
+
 	scid   = __le16_to_cpu(rsp->scid);
 	flags  = __le16_to_cpu(rsp->flags);
 	result = __le16_to_cpu(rsp->result);
@@ -4052,7 +4179,8 @@ done:
 }
 
 static inline int l2cap_disconnect_req(struct l2cap_conn *conn,
-				       struct l2cap_cmd_hdr *cmd, u8 *data)
+				       struct l2cap_cmd_hdr *cmd, u16 cmd_len,
+				       u8 *data)
 {
 	struct l2cap_disconn_req *req = (struct l2cap_disconn_req *) data;
 	struct l2cap_disconn_rsp rsp;
@@ -4060,6 +4188,9 @@ static inline int l2cap_disconnect_req(struct l2cap_conn *conn,
 	struct l2cap_chan *chan;
 	struct sock *sk;
 
+	if (cmd_len != sizeof(*req))
+		return -EPROTO;
+
 	scid = __le16_to_cpu(req->scid);
 	dcid = __le16_to_cpu(req->dcid);
 
@@ -4099,12 +4230,16 @@ static inline int l2cap_disconnect_req(struct l2cap_conn *conn,
 }
 
 static inline int l2cap_disconnect_rsp(struct l2cap_conn *conn,
-				       struct l2cap_cmd_hdr *cmd, u8 *data)
+				       struct l2cap_cmd_hdr *cmd, u16 cmd_len,
+				       u8 *data)
 {
 	struct l2cap_disconn_rsp *rsp = (struct l2cap_disconn_rsp *) data;
 	u16 dcid, scid;
 	struct l2cap_chan *chan;
 
+	if (cmd_len != sizeof(*rsp))
+		return -EPROTO;
+
 	scid = __le16_to_cpu(rsp->scid);
 	dcid = __le16_to_cpu(rsp->dcid);
 
@@ -4134,11 +4269,15 @@ static inline int l2cap_disconnect_rsp(struct l2cap_conn *conn,
 }
 
 static inline int l2cap_information_req(struct l2cap_conn *conn,
-					struct l2cap_cmd_hdr *cmd, u8 *data)
+					struct l2cap_cmd_hdr *cmd, u16 cmd_len,
+					u8 *data)
 {
 	struct l2cap_info_req *req = (struct l2cap_info_req *) data;
 	u16 type;
 
+	if (cmd_len != sizeof(*req))
+		return -EPROTO;
+
 	type = __le16_to_cpu(req->type);
 
 	BT_DBG("type 0x%4.4x", type);
@@ -4185,11 +4324,15 @@ static inline int l2cap_information_req(struct l2cap_conn *conn,
 }
 
 static inline int l2cap_information_rsp(struct l2cap_conn *conn,
-					struct l2cap_cmd_hdr *cmd, u8 *data)
+					struct l2cap_cmd_hdr *cmd, u16 cmd_len,
+					u8 *data)
 {
 	struct l2cap_info_rsp *rsp = (struct l2cap_info_rsp *) data;
 	u16 type, result;
 
+	if (cmd_len != sizeof(*rsp))
+		return -EPROTO;
+
 	type   = __le16_to_cpu(rsp->type);
 	result = __le16_to_cpu(rsp->result);
 
@@ -5055,16 +5198,16 @@ static inline int l2cap_bredr_sig_cmd(struct l2cap_conn *conn,
 
 	switch (cmd->code) {
 	case L2CAP_COMMAND_REJ:
-		l2cap_command_rej(conn, cmd, data);
+		l2cap_command_rej(conn, cmd, cmd_len, data);
 		break;
 
 	case L2CAP_CONN_REQ:
-		err = l2cap_connect_req(conn, cmd, data);
+		err = l2cap_connect_req(conn, cmd, cmd_len, data);
 		break;
 
 	case L2CAP_CONN_RSP:
 	case L2CAP_CREATE_CHAN_RSP:
-		err = l2cap_connect_create_rsp(conn, cmd, data);
+		err = l2cap_connect_create_rsp(conn, cmd, cmd_len, data);
 		break;
 
 	case L2CAP_CONF_REQ:
@@ -5072,15 +5215,15 @@ static inline int l2cap_bredr_sig_cmd(struct l2cap_conn *conn,
 		break;
 
 	case L2CAP_CONF_RSP:
-		err = l2cap_config_rsp(conn, cmd, data);
+		err = l2cap_config_rsp(conn, cmd, cmd_len, data);
 		break;
 
 	case L2CAP_DISCONN_REQ:
-		err = l2cap_disconnect_req(conn, cmd, data);
+		err = l2cap_disconnect_req(conn, cmd, cmd_len, data);
 		break;
 
 	case L2CAP_DISCONN_RSP:
-		err = l2cap_disconnect_rsp(conn, cmd, data);
+		err = l2cap_disconnect_rsp(conn, cmd, cmd_len, data);
 		break;
 
 	case L2CAP_ECHO_REQ:
@@ -5091,11 +5234,11 @@ static inline int l2cap_bredr_sig_cmd(struct l2cap_conn *conn,
 		break;
 
 	case L2CAP_INFO_REQ:
-		err = l2cap_information_req(conn, cmd, data);
+		err = l2cap_information_req(conn, cmd, cmd_len, data);
 		break;
 
 	case L2CAP_INFO_RSP:
-		err = l2cap_information_rsp(conn, cmd, data);
+		err = l2cap_information_rsp(conn, cmd, cmd_len, data);
 		break;
 
 	case L2CAP_CREATE_CHAN_REQ:
@@ -6205,12 +6348,13 @@ drop:
 	kfree_skb(skb);
 }
 
-static void l2cap_att_channel(struct l2cap_conn *conn, u16 cid,
+static void l2cap_att_channel(struct l2cap_conn *conn,
 			      struct sk_buff *skb)
 {
 	struct l2cap_chan *chan;
 
-	chan = l2cap_global_chan_by_scid(0, cid, conn->src, conn->dst);
+	chan = l2cap_global_chan_by_scid(0, L2CAP_CID_LE_DATA,
+					 conn->src, conn->dst);
 	if (!chan)
 		goto drop;
 
@@ -6259,7 +6403,7 @@ static void l2cap_recv_frame(struct l2cap_conn *conn, struct sk_buff *skb)
 		break;
 
 	case L2CAP_CID_LE_DATA:
-		l2cap_att_channel(conn, cid, skb);
+		l2cap_att_channel(conn, skb);
 		break;
 
 	case L2CAP_CID_SMP:
@@ -6313,7 +6457,7 @@ void l2cap_connect_cfm(struct hci_conn *hcon, u8 status)
 	BT_DBG("hcon %p bdaddr %pMR status %d", hcon, &hcon->dst, status);
 
 	if (!status) {
-		conn = l2cap_conn_add(hcon, status);
+		conn = l2cap_conn_add(hcon);
 		if (conn)
 			l2cap_conn_ready(conn);
 	} else {
@@ -6482,7 +6626,7 @@ int l2cap_recv_acldata(struct hci_conn *hcon, struct sk_buff *skb, u16 flags)
 		goto drop;
 
 	if (!conn)
-		conn = l2cap_conn_add(hcon, 0);
+		conn = l2cap_conn_add(hcon);
 
 	if (!conn)
 		goto drop;