| Message ID | 20190726082736.8195-1-baijiaju1990@gmail.com |
|---|---|
| State | Accepted |
| Delegated to: | David Miller |
| Headers | show |
| Series | isdn: mISDN: hfcsusb: Fix possible null-pointer dereferences in start_isoc_chain() | expand |
From: Jia-Ju Bai <baijiaju1990@gmail.com> Date: Fri, 26 Jul 2019 16:27:36 +0800 > In start_isoc_chain(), usb_alloc_urb() on line 1392 may fail > and return NULL. At this time, fifo->iso[i].urb is assigned to NULL. > > Then, fifo->iso[i].urb is used at some places, such as: > LINE 1405: fill_isoc_urb(fifo->iso[i].urb, ...) > urb->number_of_packets = num_packets; > urb->transfer_flags = URB_ISO_ASAP; > urb->actual_length = 0; > urb->interval = interval; > LINE 1416: fifo->iso[i].urb->... > LINE 1419: fifo->iso[i].urb->... > > Thus, possible null-pointer dereferences may occur. > > To fix these bugs, "continue" is added to avoid using fifo->iso[i].urb > when it is NULL. > > These bugs are found by a static analysis tool STCheck written by us. > > Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com> Applied.
diff --git a/drivers/isdn/hardware/mISDN/hfcsusb.c b/drivers/isdn/hardware/mISDN/hfcsusb.c index 0e224232f746..8fb7c5dea07f 100644 --- a/drivers/isdn/hardware/mISDN/hfcsusb.c +++ b/drivers/isdn/hardware/mISDN/hfcsusb.c @@ -1394,6 +1394,7 @@ start_isoc_chain(struct usb_fifo *fifo, int num_packets_per_urb, printk(KERN_DEBUG "%s: %s: alloc urb for fifo %i failed", hw->name, __func__, fifo->fifonum); + continue; } fifo->iso[i].owner_fifo = (struct usb_fifo *) fifo; fifo->iso[i].indx = i;
In start_isoc_chain(), usb_alloc_urb() on line 1392 may fail and return NULL. At this time, fifo->iso[i].urb is assigned to NULL. Then, fifo->iso[i].urb is used at some places, such as: LINE 1405: fill_isoc_urb(fifo->iso[i].urb, ...) urb->number_of_packets = num_packets; urb->transfer_flags = URB_ISO_ASAP; urb->actual_length = 0; urb->interval = interval; LINE 1416: fifo->iso[i].urb->... LINE 1419: fifo->iso[i].urb->... Thus, possible null-pointer dereferences may occur. To fix these bugs, "continue" is added to avoid using fifo->iso[i].urb when it is NULL. These bugs are found by a static analysis tool STCheck written by us. Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com> --- drivers/isdn/hardware/mISDN/hfcsusb.c | 1 + 1 file changed, 1 insertion(+)