A vulnerability was found in kexec, allowing the attacker to bypass the security mechanism of securelevel/secureboot combination.
When the kernel was booted with UEFI Secure Boot enabled, securelevel is set. If kexec (either through crash or admin action) is then used to load the same kernel, after reboot securelevel is disabled. In this state, the system is missing the protections provided by securelevel, for example kexec may be used to load an unsigned kernel via the legacy system call kexecload. In the securelevel patchset, the state of UEFI Secure Boot is queried in the EFI stub, and sets a bootparams flag to indicate the state of UEFI Secure Boot. This flag is then used in setuparch() to determine the correct state of securelevel. If the kernel is not booted via the EFI stub, securelevel is not set even if UEFI Secure Boot is enabled.
Patch can be found in product bug:
https://bugzilla.redhat.com/showbug.cgi?id=1243998#c3
Upstream patch:
https://github.com/mjg59/linux/commit/4b2b64d5a6ebc84214755ebccd599baef7c1b798
CVE assignment:
http://seclists.org/oss-sec/2015/q4/85
An address corruption flaw was discovered in the Linux kernel built with hardware breakpoint (CONFIGHAVEHWBREAKPOINT) support. While modifying a h/w breakpoint via 'modifyuserhwbreakpoint' routine, an unprivileged user/process could use this flaw to crash the system kernel resulting in DoS OR to potentially escalate privileges on a the system.
A flaw was found in the way the Linux kernel loaded ELF executables. Provided that an application was built as Position Independent Executable (PIE), the loader could allow part of that application's data segment to map over the memory area reserved for its stack, potentially resulting in memory corruption. An unprivileged local user with access to SUID (or otherwise privileged) PIE binary could use this flaw to escalate their privileges on the system.
Upstream patch:
https://git.kernel.org/linus/a87938b2e246b81b4fb713edb371a9fa3c5c3c86
A command injection flaw was found in the NetworkManager integration script included in the DHCP client packages in Red Hat Enterprise Linux. A malicious DHCP server, or an attacker on the local network able to spoof DHCP responses, could use this flaw to execute arbitrary commands with root privileges on systems using NetworkManager and configured to obtain network configuration using the DHCP protocol.