In the Linux kernel, the following vulnerability has been resolved:
net: ip6_gre: require CAP_NET_ADMIN in the device netns for changelink
ip6gre_changelink() and ip6erspan_changelink() operate on at most two
netns, dev_net(dev) and the tunnel link netns t->net. They differ once
the device is created in or moved to a netns other than the one the
request runs in. The rtnl changelink path checks CAP_NET_ADMIN only
against dev_net(dev), so a caller privileged there but not in t->net can
rewrite a tunnel that lives in t->net.
Gate both ops on rtnl_dev_link_net_capable() at their top, before any
attribute is parsed.
