[PATCH 06/24] Bluetooth: Exclude released devices from RFCOMMGETDEVLIST ioctl

Peter Hurley
2014-02-10T02:23:14Z

When enumerating RFCOMM devices in the rfcomm_dev_list, holding
the rfcomm_dev_lock only guarantees the existence of the enumerated
rfcomm_dev in memory, and not safe access to its state. Testing
the device state (such as RFCOMM_TTY_RELEASED) does not guarantee
the device will remain in that state for the subsequent access
to the rfcomm_dev's fields, nor guarantee that teardown has not
commenced.

Obtain an rfcomm_dev reference for the duration of rfcomm_dev
access.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
---
net/bluetooth/rfcomm/tty.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/bluetooth/rfcomm/tty.c b/net/bluetooth/rfcomm/tty.c
index 7cf193f..b385d99 100644
--- a/net/bluetooth/rfcomm/tty.c
+++ b/net/bluetooth/rfcomm/tty.c
@@ -468,7 +468,7 @@ static int rfcomm_get_dev_list(void __user *arg)
spin_lock(&rfcomm_dev_lock);

list_for_each_entry(dev, &rfcomm_dev_list, list) {
- if (test_bit(RFCOMM_TTY_RELEASED, &dev->flags))
+ if (!tty_port_get(&dev->port))
continue;
(di + n)->id = dev->id;
(di + n)->flags = dev->flags;
@@ -476,6 +476,7 @@ static int rfcomm_get_dev_list(void __user *arg)
(di + n)->channel = dev->channel;
bacpy(&(di + n)->src, &dev->src);
bacpy(&(di + n)->dst, &dev->dst);
+ tty_port_put(&dev->port);
if (++n >= dev_num)
break;
}
--
1.8.1.2