"Long-time LWN readers will know that the Linux security module
(LSM) API is controversial at best. To many, it has failed in its
purpose, which is enabling the development of competing approaches
to hardened Linux system; the only significant in-tree security
module remains SELinux.
"Meanwhile, the LSM interface is easily abused; since it allows
the insertion of hooks into almost any system operation of
interest, it can be used by other modules to provide non-security
functionality. The LSM symbols are mostly exported GPL-only, but it
is still possible for binary-only modules to abuse the LSM
operations--and, apparently, some have done so..."