apparmor: fix cred UAF caused by begin_current_label_crit_section()
In the Linux kernel, the following vulnerability has been resolved: apparmor: fix cred UAF caused by begin_current_label_crit_section() AppArmor's begin_current_label_crit_section() is a scary function called from lots of LSM hooks (in particular VFS/socket-related ones) that checks if the label referenced by the current creds is marked FLAG_STALE, and if so, attempts to use aa_replace_current_label() to replace the creds with an updated version that uses a new label. The first problem with this is that it would directly lead to UAF of `struct cred` if anything in the kernel takes a pointer to the current creds and accesses these past a se