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Net, USB, Option, hso: Do not dereference NULL pointer

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In drivers/net/usb/hso.c::hso_create_bulk_serial_device() we have this
code:
...
	serial = kzalloc(sizeof(*serial), GFP_KERNEL);
	if (!serial)
		goto exit;
...
exit:
	hso_free_tiomget(serial);
...
hso_free_tiomget() directly dereferences its argument, which in the
example above is a NULL pointer, ouch.
I could just add a 'if (serial)' test at the 'exit' label, but since most
freeing functions in the kernel accept NULL pointers (and it seems like
this was also assumed here) I opted to instead change 'hso_free_tiomget()'
so that it is safe to call it with a NULL argument. I also modified the
function to get rid of a pointles conditional before the call to
'usb_free_urb()' since that function already tests for NULL itself -
besides fixing the NULL deref this change also buys us a few bytes in
size.
Before:
$ size drivers/net/usb/hso.o
   text    data     bss     dec     hex filename
  32200     592    9960   42752    a700 drivers/net/usb/hso.o
After:
$ size drivers/net/usb/hso.o
   text    data     bss     dec     hex filename
  32196     592    9960   42748    a6fc drivers/net/usb/hso.o

Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jesper Juhl 2011-02-13 11:15:35 +00:00 • committed by David S. Miller
parent c978e7bb77
commit 5b89db0e84
1 changed files with 6 additions and 6 deletions

12
drivers/net/usb/hso.c
View file

@ -2628,15 +2628,15 @@ static struct hso_device *hso_create_net_device(struct usb_interface *interface,
static void hso_free_tiomget(struct hso_serial *serial)
{
struct hso_tiocmget *tiocmget = serial->tiocmget;
struct hso_tiocmget *tiocmget;
if (!serial)
return;
tiocmget = serial->tiocmget;
if (tiocmget) {
if (tiocmget->urb) {
usb_free_urb(tiocmget->urb);
tiocmget->urb = NULL;
}
usb_free_urb(tiocmget->urb);
tiocmget->urb = NULL;
serial->tiocmget = NULL;
kfree(tiocmget);
}
}