[Bluetooth] Fix several copy_to_user() and reference counting glitches

This patch corrects the error handling of copy_to_user() and adds more
error checks. It also fixes two reference counting bugs.

Noticed by Andi Kleen <ak@suse.de>

net/bluetooth/hci_conn.c

@@ -353,21 +353,24 @@ int hci_get_conn_list(unsigned long arg)
 	struct hci_conn_info *ci;
 	struct hci_dev *hdev;
 	struct list_head *p;
-	int n = 0, size;
+	int n = 0, size, err;
 
 	if (copy_from_user(&req, (void *) arg, sizeof(req)))
 		return -EFAULT;
 
-	if (!(hdev = hci_dev_get(req.dev_id)))
-		return -ENODEV;
-
-	size = req.conn_num * sizeof(struct hci_conn_info) + sizeof(req);
+	if (!req.conn_num || req.conn_num > (PAGE_SIZE * 2) / sizeof(*ci))
+		return -EINVAL;
 
-	if (verify_area(VERIFY_WRITE, (void *)arg, size))
-		return -EFAULT;
+	size = sizeof(req) + req.conn_num * sizeof(*ci);
 
 	if (!(cl = (void *) kmalloc(size, GFP_KERNEL)))
 		return -ENOMEM;
+
+	if (!(hdev = hci_dev_get(req.dev_id))) {
+		kfree(cl);
+		return -ENODEV;
+	}
+
 	ci = cl->conn_info;
 
 	hci_dev_lock_bh(hdev);
@@ -381,20 +384,21 @@ int hci_get_conn_list(unsigned long arg)
 		(ci + n)->out   = c->out;
 		(ci + n)->state = c->state;
 		(ci + n)->link_mode = c->link_mode;
-		n++;
+		if (++n >= req.conn_num)
+			break;
 	}
 	hci_dev_unlock_bh(hdev);
 
 	cl->dev_id = hdev->id;
 	cl->conn_num = n;
-	size = n * sizeof(struct hci_conn_info) + sizeof(req);
+	size = sizeof(req) + n * sizeof(*ci);
 
 	hci_dev_put(hdev);
 
-	copy_to_user((void *) arg, cl, size);
+	err = copy_to_user((void *) arg, cl, size);
 	kfree(cl);
 
-	return 0;
+	return err ? -EFAULT : 0;
 }
 
 int hci_get_conn_info(struct hci_dev *hdev, unsigned long arg)
@@ -407,9 +411,6 @@ int hci_get_conn_info(struct hci_dev *hdev, unsigned long arg)
 	if (copy_from_user(&req, (void *) arg, sizeof(req)))
 		return -EFAULT;
 
-	if (verify_area(VERIFY_WRITE, ptr, sizeof(ci)))
-		return -EFAULT;
-
 	hci_dev_lock_bh(hdev);
 	conn = hci_conn_hash_lookup_ba(hdev, req.type, &req.bdaddr);
 	if (conn) {
@@ -425,6 +426,5 @@ int hci_get_conn_info(struct hci_dev *hdev, unsigned long arg)
 	if (!conn)
 		return -ENOENT;
 
-	copy_to_user(ptr, &ci, sizeof(ci));
-	return 0;
+	return copy_to_user(ptr, &ci, sizeof(ci)) ? -EFAULT : 0;
 }

net/bluetooth/hci_core.c

@@ -716,22 +716,20 @@ int hci_get_dev_list(unsigned long arg)
 	struct hci_dev_list_req *dl;
 	struct hci_dev_req *dr;
 	struct list_head *p;
-	int n = 0, size;
+	int n = 0, size, err;
 	__u16 dev_num;
 
 	if (get_user(dev_num, (__u16 *) arg))
 		return -EFAULT;
 
-	if (!dev_num)
+	if (!dev_num || dev_num > (PAGE_SIZE * 2) / sizeof(*dr))
 		return -EINVAL;
-	
-	size = dev_num * sizeof(*dr) + sizeof(*dl);
 
-	if (verify_area(VERIFY_WRITE, (void *) arg, size))
-		return -EFAULT;
+	size = sizeof(*dl) + dev_num * sizeof(*dr);
 
 	if (!(dl = kmalloc(size, GFP_KERNEL)))
 		return -ENOMEM;
+
 	dr = dl->dev_req;
 
 	read_lock_bh(&hci_dev_list_lock);
@@ -746,12 +744,12 @@ int hci_get_dev_list(unsigned long arg)
 	read_unlock_bh(&hci_dev_list_lock);
 
 	dl->dev_num = n;
-	size = n * sizeof(*dr) + sizeof(*dl);
+	size = sizeof(*dl) + n * sizeof(*dr);
 
-	copy_to_user((void *) arg, dl, size);
+	err = copy_to_user((void *) arg, dl, size);
 	kfree(dl);
 
-	return 0;
+	return err ? -EFAULT : 0;
 }
 
 int hci_get_dev_info(unsigned long arg)

net/bluetooth/rfcomm/tty.c

@@ -349,7 +349,7 @@ static int rfcomm_get_dev_list(unsigned long arg)
 	struct rfcomm_dev_list_req *dl;
 	struct rfcomm_dev_info *di;
 	struct list_head *p;
-	int n = 0, size;
+	int n = 0, size, err;
 	u16 dev_num;
 
 	BT_DBG("");
@@ -357,14 +357,11 @@ static int rfcomm_get_dev_list(unsigned long arg)
 	if (get_user(dev_num, (u16 *) arg))
 		return -EFAULT;
 
-	if (!dev_num)
+	if (!dev_num || dev_num > (PAGE_SIZE * 4) / sizeof(*di))
 		return -EINVAL;
 
 	size = sizeof(*dl) + dev_num * sizeof(*di);
 
-	if (verify_area(VERIFY_WRITE, (void *)arg, size))
-		return -EFAULT;
-
 	if (!(dl = kmalloc(size, GFP_KERNEL)))
 		return -ENOMEM;
 
@@ -389,9 +386,10 @@ static int rfcomm_get_dev_list(unsigned long arg)
 	dl->dev_num = n;
 	size = sizeof(*dl) + n * sizeof(*di);
 
-	copy_to_user((void *) arg, dl, size);
+	err = copy_to_user((void *) arg, dl, size);
 	kfree(dl);
-	return 0;
+
+	return err ? -EFAULT : 0;
 }
 
 static int rfcomm_get_dev_info(unsigned long arg)
@@ -563,8 +561,10 @@ static int rfcomm_tty_open(struct tty_struct *tty, struct file *filp)
 	set_bit(RFCOMM_TTY_ATTACHED, &dev->flags);
 
 	err = rfcomm_dlc_open(dlc, &dev->src, &dev->dst, dev->channel);
-	if (err < 0)
+	if (err < 0) {
+		rfcomm_dev_put(dev);
 		return err;
+	}
 
 	/* Wait for DLC to connect */
 	add_wait_queue(&dev->wait, &wait);
@@ -589,6 +589,9 @@ static int rfcomm_tty_open(struct tty_struct *tty, struct file *filp)
 	set_current_state(TASK_RUNNING);
 	remove_wait_queue(&dev->wait, &wait);
 
+	if (err < 0)
+		rfcomm_dev_put(dev);
+
 	return err;
 }