[RFC PATCH v3 0/3] Safe, dynamically loadable LSM hooks

From: Sargun Dhillon
Date: Mon Feb 19 2018 - 21:14:07 EST


This patchset introduces safe dynamic LSM support. These are currently
not unloadable, until we figure out a use case that needs that. Adding
an unload hook is trivial given the way the patch is written.

This exposes a second mechanism of loading hooks which are in modules,
because they are behind static keys, and kept in a set of hooks which
is not marked as read only.

The point of this security feature is to resolve "unknown unknowns"
as well. Although, livepatch is excellent, sometimes, a surgical
LSM is simpler.

It includes an example LSM that prevents specific time travel.

Changes since v2:
* inode get/set security is readded
* xfrm singleton hook readded
* Security hooks are turned into an array
* Security hooks and dynamic hooks enum is collapsed

Changes since v1:
* It no longer allows unloading of modules
* prctl is fixed
* inode get/set security is removed
* xfrm singleton hook removed


Sargun Dhillon (3):
security: Refactor LSM hooks into an array
security: Expose a mechanism to load lsm hooks dynamically at runtime
security: Add an example sample dynamic LSM

include/linux/lsm_hooks.h | 454 ++++++++++++++++++++++++----------------------
samples/Kconfig | 6 +
samples/Makefile | 2 +-
samples/lsm/Makefile | 4 +
samples/lsm/lsm_example.c | 33 ++++
security/Kconfig | 9 +
security/inode.c | 13 +-
security/security.c | 250 +++++++++++++++++++++++--
8 files changed, 531 insertions(+), 240 deletions(-)
create mode 100644 samples/lsm/Makefile
create mode 100644 samples/lsm/lsm_example.c

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2.14.1