Red Hat Security Advisory: kernel security and bug fix update

Important

A flaw was found in KVM. When updating a guest's page table entry, vm_pgoff was improperly used as the offset to get the page's pfn. As vaddr and vm_pgoff are controllable by user-mode processes, this flaw allows unprivileged local users on the host to write outside the userspace region and potentially corrupt the kernel, resulting in a denial of service condition.

CWE-416 - Use After Free

An integer coercion error was found in the openvswitch kernel module. Given a sufficiently large number of actions, while copying and reserving memory for a new action of a new flow, the reserve_sfa_size() function does not return -EMSGSIZE as expected, potentially leading to an out-of-bounds write access. This flaw allows a local user to crash or potentially escalate their privileges on the system.

CWE-681 - Incorrect Conversion between Numeric Types

A race condition was found in the Linux kernel's watch queue due to a missing lock in the pipe_resize_ring(). The race condition occurs when a thread uses ioctl(IOC_WATCH_QUEUE_SET_SIZE) to resize the pipe buffer and free the old pipe buffer, while another thread uses keyctl() to trigger a notification in the watch queue, calling post_one_notification() and accessing the freed pipe buffer. This flaw allows a local user to crash the system or escalate their privileges on the system.

CWE-820 - Missing Synchronization