RE: [PATCH 12/26] netfilter: switch nf_setsockopt to sockptr_t

[David Laight <David.Laight@ACULAB.COM>]

From: Christoph Hellwig
> Sent: 27 July 2020 17:24
> 
> On Mon, Jul 27, 2020 at 06:16:32PM +0200, Jason A. Donenfeld wrote:
> > Maybe sockptr_advance should have some safety checks and sometimes
> > return -EFAULT? Or you should always use the implementation where
> > being a kernel address is an explicit bit of sockptr_t, rather than
> > being implicit?
> 
> I already have a patch to use access_ok to check the whole range in
> init_user_sockptr.

That doesn't make (much) difference to the code paths that ignore
the user-supplied length.
OTOH doing the user/kernel check on the base address (not an
incremented one) means that the correct copy function is always
selected.

Perhaps the functions should all be passed a 'const sockptr_t'.
The typedef could be made 'const' - requiring non-const items
explicitly use the union/struct itself.

	David

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