Linux 6.15 Merge Window

Linux v6.14 was released two weeks ago on March 24th, with the Linux v6.15 merge window opening immediately afterwards. Below are the highlights of the LSM and SELinux pull requests which have been merged into Linus’ tree. There were no patches queued in the audit tree for Linux v6.15.

LSM

• While only tangentially related to the LSM framework, due to a lack of a clear maintainer for the Linux kernel’s credentials code, I have volunteered to serve in that role and Serge Hallyn has volunteered to serve as a formal reviewer. Considering the relatively low volume of credential related patches, I plan to accept the patches into the LSM tree, but this could change in the future if the volume increases.

• Minor updates to the Rust LSM and credentials bindings, fixing code comments and inlining several methods.

• Remove an unused parameter from the security_perf_event_open() LSM hook.

SELinux

• Add a new LSM hook and SELinux implementation to the io_uring_allowed() function. The new SELinux permission, io_uring/allowed, controls the ability of the currently running SELinux domain to use the io_uring_setup(2) syscall.

• Add additional SELinux access controls for kernel file reads and loads from userspace. The new controls add support for firmware images via the system/firmware_load permission, kexec kernels via system/kexec_image_load, kexec initramfs images via system/kexec_initramfs_load, system policies via system/policy_load, and X.509 certificates via system/x509_certificate_load.

• Add the file/watch_mountns permission to control access to watching for changes to the mount namespace. Changes include the addition of a new filesystem mount, removal of an existing mount, or moving a mount in a namespace.

• Add support for network interface name wildcard matching in SELinux policy. This makes it easier for policy developers to support tools which auto generate network interfaces according to a pattern, e.g. nic0, nic1, nic2, etc. In order to enable the wildcard matching in the SELinux policy, the policy must also set the netif_wildcard policy capability.

• Fix a potential future issue in the SELinux kernel read file controls. While this wasn’t a problem with the existing SELinux kernel module read controls, there was an issue where SELinux did not properly enforce policy on the kernel’s chunked file reads. As this was fixed at the same time we added support for kernel file read types that include chunked reads, users do not have to worry about security regressions or vulnerabilities related to this issue.

• Fix a subshell error handling issue in the kernel’s example policy loading script. Error conditions should now be properly caught and error messages displayed to the caller.