MGASA-2016-0014

This kernel-linus update is based on upstream 4.1.15 longterm kernel and fixes the following security issues:

The virtnetprobe function in drivers/net/virtionet.c in the Linux kernel before 4.2 attempts to support a FRAGLIST feature without proper memory allocation, which allows guest OS users to cause a denial of service (buffer overflow and memory corruption) via a crafted sequence of fragmented packets (CVE-2015-5156).

The KVM subsystem in the Linux kernel through 4.2.6, and Xen 4.3.x through 4.6.x, allows guest OS users to cause a denial of service (host OS panic or hang) by triggering many #AC (aka Alignment Check) exceptions, related to svm.c and vmx.c (CVE-2015-5307).

The _rdsconn_create function in net/rds/connection.c in the Linux kernel through 4.2.3 allows local users to cause a denial of service (NULL pointer dereference and system crash) or possibly have unspecified other impact by using a socket that was not properly bound (CVE-2015-6937).

The keygcunused_keys function in security/keys/gc.c in the Linux kernel through 4.2.6 allows local users to cause a denial of service (OOPS) via crafted keyctl commands (CVE-2015-7872).

The vividfbioctl function in drivers/media/platform/vivid/vivid-osd.c in the Linux kernel through 4.3.3 does not initialize a certain structure member, which allows local users to obtain sensitive information from kernel memory via a crafted application (CVE-2015-7884).

The dgncmgmtioctl function in drivers/staging/dgnc/dgnc_mgmt.c in the Linux kernel through 4.3.3 does not initialize a certain structure member, which allows local users to obtain sensitive information from kernel memory via a crafted application (CVE-2015-7885).

Felix Wilhelm discovered a race condition in the Xen paravirtualized drivers which can cause double fetch vulnerabilities. An attacker in the paravirtualized guest could exploit this flaw to cause a denial of service (crash the host) or potentially execute arbitrary code on the host (CVE-2015-8550 / XSA-155).

Konrad Rzeszutek Wilk discovered the Xen PCI backend driver does not perform sanity checks on the device's state. An attacker could exploit this flaw to cause a denial of service (NULL dereference) on the host (CVE-2015-8551 / XSA-157).

Konrad Rzeszutek Wilk discovered the Xen PCI backend driver does not perform sanity checks on the device's state. An attacker could exploit this flaw to cause a denial of service by flooding the logging system with WARN() messages causing the initial domain to exhaust disk space (CVE-2015-8552 / XSA-157).

The ovl_setattr function in fs/overlayfs/inode.c in the Linux kernel through 4.3.3 attempts to merge distinct setattr operations, which allows local users to bypass intended access restrictions and modify the attributes of arbitrary overlay files via a crafted application (CVE-2015-8660).

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