From 8eaca8d1caac22e826055369225d5718119e3f80 Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Fri, 14 May 2021 17:24:48 +0300 Subject: [PATCH] net: hso: check for allocation failure in hso_create_bulk_serial_device() [ Upstream commit 31db0dbd72444abe645d90c20ecb84d668f5af5e ] 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 Reviewed-by: Johan Hovold Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- 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 01566e4..88f8778 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; -- 2.7.4