USB: ssu100: fix use-after-free in TIOCMIWAIT
commit 43a66b4c417ad15f6d2f632ce67ad195bdf999e8 upstream.
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.
Signed-off-by: Johan Hovold <jhovold@gmail.com>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/serial/ssu100.c b/drivers/usb/serial/ssu100.c
index b8db69d..d19fa6a 100644
--- a/drivers/usb/serial/ssu100.c
+++ b/drivers/usb/serial/ssu100.c
@@ -77,7 +77,6 @@
spinlock_t status_lock;
u8 shadowLSR;
u8 shadowMSR;
- wait_queue_head_t delta_msr_wait; /* Used for TIOCMIWAIT */
struct async_icount icount;
};
@@ -386,8 +385,9 @@
spin_unlock_irqrestore(&priv->status_lock, flags);
while (1) {
- wait_event_interruptible(priv->delta_msr_wait,
- ((priv->icount.rng != prev.rng) ||
+ wait_event_interruptible(port->delta_msr_wait,
+ (port->serial->disconnected ||
+ (priv->icount.rng != prev.rng) ||
(priv->icount.dsr != prev.dsr) ||
(priv->icount.dcd != prev.dcd) ||
(priv->icount.cts != prev.cts)));
@@ -395,6 +395,9 @@
if (signal_pending(current))
return -ERESTARTSYS;
+ if (port->serial->disconnected)
+ return -EIO;
+
spin_lock_irqsave(&priv->status_lock, flags);
cur = priv->icount;
spin_unlock_irqrestore(&priv->status_lock, flags);
@@ -477,7 +480,6 @@
}
spin_lock_init(&priv->status_lock);
- init_waitqueue_head(&priv->delta_msr_wait);
usb_set_serial_port_data(port, priv);
return ssu100_initdevice(serial->dev);
@@ -563,7 +565,7 @@
priv->icount.dcd++;
if (msr & UART_MSR_TERI)
priv->icount.rng++;
- wake_up_interruptible(&priv->delta_msr_wait);
+ wake_up_interruptible(&port->delta_msr_wait);
}
}