af_802154: Disable auto-loading as mitigation against local exploits

af_802154: Disable auto-loading as mitigation against local exploits

Recent review has revealed several bugs in obscure protocol
implementations that can be exploited by local users for denial of
service or privilege escalation.  We can mitigate the effect of any
remaining vulnerabilities in such protocols by preventing unprivileged
users from loading the modules, so that they are only exploitable on
systems where the administrator has chosen to load the protocol.

The 'af_802154' (IEEE 802.15.4) protocol is not widely used, was
not present in the 'lenny' kernel, and seems to receive only sporadic
maintenance.  Therefore disable auto-loading.

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Gbp-Pq: Topic debian
Gbp-Pq: Name af_802154-Disable-auto-loading-as-mitigation-against.patch