USB: mos7840: fix use-after-free in TIOCMIWAIT
Use the port wait queue and make sure to check the serial disconnected
flag before accessing private port data after waking up.
This is is needed as the private port data (including the wait queue
itself) can be gone when waking up after a disconnect.
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/serial/mos7840.c b/drivers/usb/serial/mos7840.c
index 1b83b01..b8051fa 100644
--- a/drivers/usb/serial/mos7840.c
+++ b/drivers/usb/serial/mos7840.c
@@ -219,7 +219,6 @@
char open;
char open_ports;
wait_queue_head_t wait_chase; /* for handling sleeping while waiting for chase to finish */
- wait_queue_head_t delta_msr_wait; /* for handling sleeping while waiting for msr change to happen */
int delta_msr_cond;
struct async_icount icount;
struct usb_serial_port *port; /* loop back to the owner of this object */
@@ -425,7 +424,7 @@
}
mos7840_port->delta_msr_cond = 1;
- wake_up_interruptible(&mos7840_port->delta_msr_wait);
+ wake_up_interruptible(&port->port->delta_msr_wait);
}
}
@@ -1130,7 +1129,6 @@
/* initialize our wait queues */
init_waitqueue_head(&mos7840_port->wait_chase);
- init_waitqueue_head(&mos7840_port->delta_msr_wait);
/* initialize our icount structure */
memset(&(mos7840_port->icount), 0x00, sizeof(mos7840_port->icount));
@@ -2220,13 +2218,18 @@
while (1) {
/* interruptible_sleep_on(&mos7840_port->delta_msr_wait); */
mos7840_port->delta_msr_cond = 0;
- wait_event_interruptible(mos7840_port->delta_msr_wait,
- (mos7840_port->
+ wait_event_interruptible(port->delta_msr_wait,
+ (port->serial->disconnected ||
+ mos7840_port->
delta_msr_cond == 1));
/* see if a signal did it */
if (signal_pending(current))
return -ERESTARTSYS;
+
+ if (port->serial->disconnected)
+ return -EIO;
+
cnow = mos7840_port->icount;
smp_rmb();
if (cnow.rng == cprev.rng && cnow.dsr == cprev.dsr &&
