Oracle Linux: CVE-2024-42318: ELSA-2024-12815: Unbreakable Enterprise kernel security update (IMPORTANT) (Multiple Advisories)

Description

In the Linux kernel, the following vulnerability has been resolved: landlock: Don't lose track of restrictions on cred_transfer When a process' cred struct is replaced, this _almost_ always invokes the cred_prepare LSM hook; but in one special case (when KEYCTL_SESSION_TO_PARENT updates the parent's credentials), the cred_transfer LSM hook is used instead. Landlock only implements the cred_prepare hook, not cred_transfer, so KEYCTL_SESSION_TO_PARENT causes all information on Landlock restrictions to be lost. This basically means that a process with the ability to use the fork() and keyctl() syscalls can get rid of all Landlock restrictions on itself. Fix it by adding a cred_transfer hook that does the same thing as the existing cred_prepare hook. (Implemented by having hook_cred_prepare() call hook_cred_transfer() so that the two functions are less likely to accidentally diverge in the future.) A vulnerability was found in the Linux kernel's `axi_chan_handle_err` function, which caused a kernel panic due to NULL pointer dereferencing. This issue has been fixed. The update protects the `vd` variable to prevent such crashes. The `axi_chan_block_xfer_complete` function was used as a reference for this improvement, enhancing system stability during exceptional cases.