Affected: Linux, Siemens RUGGEDCOM RST2428P, Siemens SCALANCE XC-300/XR-300/XC-400/XR-500WG/XR-500 family, Siemens SCALANCE XCM-/XRM-/XCH-/XRH-300 family, Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP, Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP, Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP

In the Linux kernel, the following vulnerability has been resolved:

um: Add winch to winch_handlers before registering winch IRQ

Registering a winch IRQ is racy, an interrupt may occur before the winch is added to the winch_handlers list.

If that happens, register_winch_irq() adds to that list a winch that is scheduled to be (or has already been) freed, causing a panic later in winch_cleanup().

Avoid the race by adding the winch to the winch_handlers list before registering the IRQ, and rolling back if um_request_irq() fails.

Affected: Ubuntu:Pro:18.04:LTS: linux-aws-5.4, Ubuntu:Pro:18.04:LTS: linux-gcp-5.4, Ubuntu:Pro:18.04:LTS: linux-hwe-5.4, Ubuntu:Pro:18.04:LTS: linux-ibm-5.4, Ubuntu:20.04:LTS: linux, Ubuntu:20.04:LTS: linux-aws, Ubuntu:20.04:LTS: linux-gcp, Ubuntu:20.04:LTS: linux-gkeop, Ubuntu:20.04:LTS: linux-ibm, Ubuntu:20.04:LTS: linux-iot and 3 more

Several security issues were discovered in the Linux kernel. An attacker could possibly use these to compromise the system. This update corrects flaws in the following subsystems: - ARM64 architecture; - M68K architecture; - User-Mode Linux (UML); - x86 architecture; - Accessibility subsystem; - Character device driver; - Clock framework and drivers; - CPU frequency scaling framework; - Hardware crypto device drivers; - Buffer Sharing and Synchronization framework; - FireWire subsystem; - GPU drivers; - HW tracing; - Macintosh device drivers; - Multiple devices driver; - Media drivers; - Network drivers; - Pin controllers subsystem; - S/390 drivers; - SCSI drivers; - SoundWire subsystem; - Greybus lights staging drivers; - TTY drivers; - Framebuffer layer; - Virtio drivers; - 9P distributed file system; - eCrypt file system; - EROFS file system; - Ext4 file system; - F2FS file system; - JFFS2 file system; - Network file system client; - NILFS2 file system; - SMB network file system; - Kernel debugger infrastructure; - IRQ subsystem; - Tracing infrastructure; - Dynamic debug library; - 9P file system network protocol; - Bluetooth subsystem; - Networking core; - IPv4 networking; - IPv6 networking; - Netfilter; - NET/ROM layer; - NFC subsystem; - NSH protocol; - Open vSwitch; - Phonet protocol; - TIPC protocol; - Unix domain sockets; - Wireless networking; - eXpress Data Pa…