Oracle Linux: CVE-2017-6347: ELSA-2017-3539: Unbreakable Enterprise kernel security update (IMPORTANT)

The ip_cmsg_recv_checksum function in net/ipv4/ip_sockglue.c in the Linux kernel before 4.10.1 has incorrect expectations about skb data layout, which allows local users to cause a denial of service (buffer over-read) or possibly have unspecified other impact via crafted system calls, as demonstrated by use of the MSG_MORE flag in conjunction with loopback UDP transmission.
The skbs processed by ip_cmsg_recv() are not guaranteed to be linear (e.g. when sending UDP packets over loopback with MSGMORE). Using csum_partial() on potentially the whole skb len is dangerous; instead be on the safe side and use skb_checksum(). This may lead to an infoleak as the kernel memory may be checksummed and sent as part of the packet.