From 5b89db0e84bef81f6aa324f8f22a9258ff873de3 Mon Sep 17 00:00:00 2001 From: Jesper Juhl Date: Sun, 13 Feb 2011 11:15:35 +0000 Subject: [PATCH] Net, USB, Option, hso: Do not dereference NULL pointer 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 Signed-off-by: David S. Miller --- drivers/net/usb/hso.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/drivers/net/usb/hso.c b/drivers/net/usb/hso.c index bed8fcedff49..6d83812603b6 100644 --- a/drivers/net/usb/hso.c +++ b/drivers/net/usb/hso.c @@ -2628,15 +2628,15 @@ exit: 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); - } } -- 2.30.2