Merge branch 'net-control-the-length-of-the-altname-list'

Jakub Kicinski says:

====================
net: control the length of the altname list

Count the memory used for altnames and don't let user
overflow the property nlattr. This was reported by George:
https://lore.kernel.org/all/3e564baf-a1dd-122e-2882-ff143f7eb578@gmail.com/
====================

Link: https://lore.kernel.org/r/20220309182914.423834-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>