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Message-Id: <20190726082736.8195-1-baijiaju1990@gmail.com>
Date: Fri, 26 Jul 2019 16:27:36 +0800
From: Jia-Ju Bai <baijiaju1990@...il.com>
To: isdn@...ux-pingi.de, davem@...emloft.net, pakki001@....edu,
tranmanphong@...il.com, gregkh@...uxfoundation.org,
rfontana@...hat.com, gustavo@...eddedor.com, tglx@...utronix.de
Cc: netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
Jia-Ju Bai <baijiaju1990@...il.com>
Subject: [PATCH] isdn: mISDN: hfcsusb: Fix possible null-pointer dereferences in start_isoc_chain()
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@...il.com>
---
drivers/isdn/hardware/mISDN/hfcsusb.c | 1 +
1 file changed, 1 insertion(+)
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;
--
2.17.0
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