CVE request: kernel: logic error in INET_DIAG bytecode auditing

[Nelson Elhage <nelhage () ksplice com>]

INET_DIAG is inconsistent about how it looks up the bytecode contained in a
netlink message, making it possible for a user to cause the kernel to execute
unaudited INET_DIAG bytecode.

This can be abused to make the kernel enter an infinite loop, and possibly other
consequences, although I haven't thought of anything else interesting.

Reference:
http://www.spinics.net/lists/netdev/msg145899.html

- Nelson