On Fri, Jan 13, 2017 at 02:55:14PM +0100, Florian Westphal wrote:
> Dan reports following smatch warning:
> net/xfrm/xfrm_state.c:659
> error: we previously assumed 'afinfo' could be null (see line 651)
>
> 649 struct xfrm_state_afinfo *afinfo = xfrm_state_afinfo_get_rcu(family);
> 651 if (afinfo)
> ...
> 658 }
> 659 afinfo->init_temprop(x, tmpl, daddr, saddr);
>
> I am resonably sure afinfo cannot be NULL here.
>
> xfrm_state4.c and state6.c are both part of ipv4/ipv6 (depends on
> CONFIG_XFRM, a boolean) but even if ipv6 is a module state6.c can't
> be removed (ipv6 lacks module_exit so it cannot be removed).
>
> The only callers for xfrm6_fini that leads to state backend unregister
> are error unwinding paths that can be called during ipv6 init function.
>
> So after ipv6 module is loaded successfully the state backend cannot go
> away anymore.
>
> The family value from policy lookup path is taken from dst_entry, so
> that should always be AF_INET(6).
>
> However, since this silences the warning and avoids readers of this
> code wondering about possible null deref it seems preferrable to
> be defensive and just add the old check back.
>
> Fixes: 711059b9752ad0 ("xfrm: add and use xfrm_state_afinfo_get_rcu")
> Reported-by: Dan Carpenter <[email protected]>
> Signed-off-by: Florian Westphal <[email protected]>
Applied to ipsec-next, thanks!
