Increased the deprecation sleep penalty for both the checkreqprot and the runtime disable options from 5 to 15 seconds. With only one problem report, from a neglected test machine, since we started deprecating these configuration options, I expect we will disable both options completely in an upcoming kernel release, likely as soon as Linux v6.4. See the SELinux kernel wiki pages, linked above, for more information if you still rely on either of these options.

When a new SELinux policy is loaded, the kernel’s internal SELinux label tables need to be updated and converted from the old policy to the new, this is handled by the “sidtab conversion” code. Previously this code relied on indirect function calls for some of its work, but in this kernel release we’ve replaced the indirect calls with direct calls in an effort to make the code cleaner, easier to understand, and more maintainable in the long term.

Minor changes were made to the security_socket_getpeersec_stream() LSM hook, and SELinux implementation, to match recent changes in the core networking code which impacted the LSM hook’s parameter types.

Minor changes to support the POSIX ACL updates in the core VFS code.

This patch implements a new user_namespace { create } access control permission to restrict which domains allow or deny user namespace creation. This is necessary for system administrators to quickly protect their systems while waiting for vulnerability patches to be applied.

This permission can be used in the following way:

allow domA_t domA_t : user_namespace { create };

While not strictly a SELinux change, the userfaultfd subsystem was changed to always create userfaultfds with O_RDONLY permissions instead of O_RDWR. This should have no functional change, as userfaultfds have always been read-only, however opening the file descriptor with a read-write permission request caused SELinux to check for both read and write permissions. With this change SELinux should now only request the read permission when a userfaultfd is opened.

Fix a bug caused by how the kernel was allocating memory during a policy reload. The kernel was allocating memory for a label conversion using a blocking mechanism while a lock was held, raising the risk of a deadlock/panic. This fix changes the kernel code to use a non-blocking allocation in this case, eliminating the risk of deadlock/panic.

Convert all of the SELinux policy boolean values in the kernel to use a single type: signed integers. Prior to this change the booleans were represented by a mix of signed and unsigned integer types; we do not believe this was the source of any problems, but type consistency is important to ensuring problem-free code.

Convert the SELinux policy install script tool to use grep -E instead of the egrep tool, which has been marked obsolete.

Remove more references to the SELinux runtime disable functionality as we are in the process of deprecating this functionality.

Change the kernel to only free the “proctitle” information on task exit, allowing the kernel to cache the string across multiple syscalls. While the patch description did not provide any before-and-after performance measurements, this should improve audit performance slightly.

Make use of the kernel’s existing time comparison functions instead of open coding the time comparisons directly in the audit kernel code.

Minor improvements to the way values are compared in the kernel code. It isn’t believed that any of these comparisons were the source of any audit problems, but these changes should help ensure proper behavior in future releases.

Minor cleanups to improve the comments in the code and remove unused or redundant code.

Add a SELinux access control for the iouring IORING_OP_URING_CMD command. This includes the addition of a new permission in the existing “io_uring” object class: “cmd”. The subject of the new permission check is the domain of the process requesting access, the object is the open file which points to the device/file that is the target of the IORING_OP_URING_CMD operation. A sample policy rule is shown below:

allow <domain> <file>:io_uring { cmd };

Added support for proper labeling of memfd_secret anonymous inodes. This allows LSMs, such as SELinux, that implement the anonymous inode hooks to apply security policy to memfd_secret file descriptors.

Various small improvements to the SELinux kernel memory management code including fixing memory leaks, freeing memory when it is no longer needed, randomizing internal data structures, and adding boundary checks to memory accesses.

Fixed a bug where the syscall return codes were not properly set before the filtering rules were executed. This resolved a problem where audit filter rules involving syscall return codes were not properly triggering on matching syscall events.

Fixed a potential double free on a fsnotify error path.

Fixed a memory leak in the io_uring audit code.

Minor internal improvements to remove redundant code and mark private functions as static.