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SubjectRe: [PATCH] Net, USB, Option, hso: Do not dereference NULL pointer
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From: Jesper Juhl <jj@chaosbits.net>
Date: Sun, 13 Feb 2011 22:15:35 +0100 (CET)

> 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>

Applied.


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