CVE request - kernel: ip6_dst_lookup_tail() NULL pointer dereference

[Eugene Teo <eugene () redhat com>]

ipv6: Fix OOPS in ip6_dst_lookup_tail().

This fixes kernel bugzilla 11469: "TUN with 1024 neighbours:
ip6_dst_lookup_tail NULL crash"

dst->neighbour is not necessarily hooked up at this point in the 
processing path, so blindly dereferencing it is the wrong thing to do. 
This NULL check exists in other similar paths and this case was just an 
oversight.

Also fix the completely wrong and confusing indentation here while we're 
at it.

References:
http://bugzilla.kernel.org/show_bug.cgi?id=11469
https://bugzilla.redhat.com/show_bug.cgi?id=563781

Upstream patch:
http://git.kernel.org/linus/e550dfb0c2c31b6363aa463a035fc9f8dcaa3c9b

Thanks, Eugene
--
Eugene Teo / Red Hat Security Response Team