1) Netlink socket dumping had several missing verifications and checks.
In particular, address comparisons in the request byte code
interpreter could access past the end of the address in the
inet_request_sock.
Also, address family and address prefix lengths were not validated
properly at all.
This means arbitrary applications can read past the end of certain
kernel data structures.
Fixes from Neal Cardwell.
2) ip_check_defrag() operates in contexts where we're in the process
of, or about to, input the packet into the real protocols
(specifically macvlan and AF_PACKET snooping).
Unfortunately, it does a pskb_may_pull() which can modify the
backing packet data which is not legal if the SKB is shared. It
very much can be shared in this context.
Deal with the possibility that the SKB is segmented by using
skb_copy_bits().
Fix from Johannes Berg based upon a report by Eric Leblond.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net:
ipv4: ip_check_defrag must not modify skb before unsharing
inet_diag: validate port comparison byte code to prevent unsafe reads
inet_diag: avoid unsafe and nonsensical prefix matches in inet_diag_bc_run()
inet_diag: validate byte code to prevent oops in inet_diag_bc_run()
inet_diag: fix oops for IPv4 AF_INET6 TCP SYN-RECV state