MGASA-2017-0088

This kernel update is based on upstream 4.4.55 and fixes at least the following security issues: Race condition in drivers/tty/n_hdlc.c in the Linux kernel through 4.10.1 allows local users to gain privileges or cause a denial of service (double free) by setting the HDLC line discipline (CVE-2017-2636). Race condition in net/packet/af_packet.c in the Linux kernel before 4.9.13 allows local users to cause a denial of service (use-after-free) or possibly have unspecified other impact via a multithreaded application that makes PACKET_FANOUT setsockopt system calls (CVE-2017-6346). 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 (CVE-2017-6347). The hashbin_delete function in net/irda/irqueue.c in the Linux kernel before 4.9.13 improperly manages lock dropping, which allows local users to cause a denial of service (deadlock) via crafted operations on IrDA devices (CVE-2017-6348). For other upstream fixes in this update, see the referenced changelogs.