MGASA-2016-0364

This update is based on the upstream 4.4.26 kernel and fixes at least these security issues:

sound/core/timer.c in the Linux kernel through 4.6 does not initialize certain r1 data structures, which allows local users to obtain sensitive information from kernel stack memory via crafted use of the ALSA timer interface, related to the (1) sndtimeruserccallback and (2) sndtimerusertinterrupt functions (CVE-2016-4578).

A race condition was found in the way the Linux kernel's memory subsystem handled the copy-on-write (COW) breakage of private read-only memory mappings. An unprivileged local user could use this flaw to gain write access to otherwise read-only memory mappings and thus increase their privileges on the system. This could be abused by an attacker to modify existing setuid files with instructions to elevate privileges. An exploit using this technique has been found in the wild (CVE-2016-5195).

The tipcnlcompatlinkdump function in net/tipc/netlink_compat.c in the Linux kernel through 4.6.3 does not properly copy a certain string, which allows local users to obtain sensitive information from kernel stack memory by reading a Netlink message (CVE-2016-5243).

The rdsincinfo_copy function in net/rds/recv.c in the Linux kernel through 4.6.3 does not initialize a certain structure member, which allows remote attackers to obtain sensitive information from kernel stack memory by reading an RDS message (CVE-2016-5244).

Memory leak in the airspyprobe function in drivers/media/usb/airspy/airspy.c in the airspy USB driver in the Linux kernel before 4.7 allows local users to cause a denial of service (memory consumption) via a crafted USB device that emulates many VFLTYPESDR or VFLTYPE_SUBDEV devices and performs many connect and disconnect operations (CVE-2016-5400).

Race condition in the ioctlsendfib function in drivers/scsi/aacraid/commctrl.c in the Linux kernel through 4.7 allows local users to cause a denial of service (out-of-bounds access or system crash) by changing a certain size value, aka a "double fetch" vulnerability (CVE-2016-6480).

Marco Grassi discovered a use-after-free condition could occur in the TCP retransmit queue handling code in the Linux kernel. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2016-6828)

Vladimir Bene discovered an unbounded recursion in the VLAN and TEB Generic Receive Offload (GRO) processing implementations in the Linux kernel, A remote attacker could use this to cause a stack corruption, leading to a denial of service (system crash). (CVE-2016-7039)

This update also changes the following: - enables STRICTDEVMEM as a security hardening - disables FWLOADERUSERHELPER_FALLBACK again (un-intentionally enabled in 4.4 series upgrade) that slows down boot or even makes wireless connection fail with drivers with multiple possible firmwares (mga#19390).

For other fixes in this update, see the referenced changelogs.