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net: hso: check for allocation failure in hso_create_bulk_serial_device()

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In current kernels, small allocations never actually fail so this
patch shouldn't affect runtime.

Originally this error handling code written with the idea that if
the "serial->tiocmget" allocation failed, then we would continue
operating instead of bailing out early.  But in later years we added
an unchecked dereference on the next line.

	serial->tiocmget->serial_state_notification = kzalloc();
        ^^^^^^^^^^^^^^^^^^

Since these allocations are never going fail in real life, this is
mostly a philosophical debate, but I think bailing out early is the
correct behavior that the user would want.  And generally it's safer to
bail as soon an error happens.

Fixes: af0de1303c ("usb: hso: obey DMA rules in tiocmget")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Johan Hovold <johan@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Dan Carpenter 2021-05-14 17:24:48 +03:00 • committed by David S. Miller
parent b7df21cf1b
commit 31db0dbd72
1 changed files with 18 additions and 19 deletions
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37
drivers/net/usb/hso.c
View file

@ -2618,29 +2618,28 @@ static struct hso_device *hso_create_bulk_serial_device(
num_urbs = 2; num_urbs = 2;
serial->tiocmget = kzalloc(sizeof(struct hso_tiocmget), serial->tiocmget = kzalloc(sizeof(struct hso_tiocmget),
GFP_KERNEL); GFP_KERNEL);
if (!serial->tiocmget)
goto exit;
serial->tiocmget->serial_state_notification serial->tiocmget->serial_state_notification
= kzalloc(sizeof(struct hso_serial_state_notification), = kzalloc(sizeof(struct hso_serial_state_notification),
GFP_KERNEL); GFP_KERNEL);
/* it isn't going to break our heart if serial->tiocmget if (!serial->tiocmget->serial_state_notification)
* allocation fails don't bother checking this. goto exit;
*/ tiocmget = serial->tiocmget;
if (serial->tiocmget && serial->tiocmget->serial_state_notification) { tiocmget->endp = hso_get_ep(interface,
tiocmget = serial->tiocmget; USB_ENDPOINT_XFER_INT,
tiocmget->endp = hso_get_ep(interface, USB_DIR_IN);
USB_ENDPOINT_XFER_INT, if (!tiocmget->endp) {
USB_DIR_IN); dev_err(&interface->dev, "Failed to find INT IN ep\n");
if (!tiocmget->endp) { goto exit;
dev_err(&interface->dev, "Failed to find INT IN ep\n");
goto exit;
}
tiocmget->urb = usb_alloc_urb(0, GFP_KERNEL);
if (tiocmget->urb) {
mutex_init(&tiocmget->mutex);
init_waitqueue_head(&tiocmget->waitq);
} else
hso_free_tiomget(serial);
} }
tiocmget->urb = usb_alloc_urb(0, GFP_KERNEL);
if (tiocmget->urb) {
mutex_init(&tiocmget->mutex);
init_waitqueue_head(&tiocmget->waitq);
} else
hso_free_tiomget(serial);
} }
else else
num_urbs = 1; num_urbs = 1;