[PATCH v2 net] net: hso: check for allocation failure in hso_create_bulk_serial_device()
STALE1964d
From: Dan Carpenter <hidden>
Date: 2021-05-14 14:26:40
Also in:
kernel-janitors, linux-usb
Subsystem:
hso 3g modem driver, networking drivers, the rest, usb networking drivers · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
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: af0de1303c4e ("usb: hso: obey DMA rules in tiocmget")
Signed-off-by: Dan Carpenter <redacted>
---
v2: Do more extensive clean up. As Johan pointed out the comments and
later NULL checks can be removed.
drivers/net/usb/hso.c | 37 ++++++++++++++++++-------------------
1 file changed, 18 insertions(+), 19 deletions(-)
diff --git a/drivers/net/usb/hso.c b/drivers/net/usb/hso.c
index 3ef4b2841402..260f850d69eb 100644
--- a/drivers/net/usb/hso.c
+++ b/drivers/net/usb/hso.c@@ -2618,29 +2618,28 @@ static struct hso_device *hso_create_bulk_serial_device( num_urbs = 2; serial->tiocmget = kzalloc(sizeof(struct hso_tiocmget), GFP_KERNEL); + if (!serial->tiocmget) + goto exit; serial->tiocmget->serial_state_notification = kzalloc(sizeof(struct hso_serial_state_notification), GFP_KERNEL); - /* it isn't going to break our heart if serial->tiocmget - * allocation fails don't bother checking this. - */ - if (serial->tiocmget && serial->tiocmget->serial_state_notification) { - tiocmget = serial->tiocmget; - tiocmget->endp = hso_get_ep(interface, - USB_ENDPOINT_XFER_INT, - USB_DIR_IN); - if (!tiocmget->endp) { - 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); + if (!serial->tiocmget->serial_state_notification) + goto exit; + tiocmget = serial->tiocmget; + tiocmget->endp = hso_get_ep(interface, + USB_ENDPOINT_XFER_INT, + USB_DIR_IN); + if (!tiocmget->endp) { + 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); } else num_urbs = 1;
--
2.30.2