On 21/08/2017 02:09, Mickaël Salaün wrote:

Handle 33 filesystem-related LSM hooks for the Landlock filesystem
event: LANDLOCK_SUBTYPE_EVENT_FS.

A Landlock event wrap LSM hooks for similar kernel object types (e.g.
struct file, struct path...). Multiple LSM hooks can trigger the same
Landlock event.

Landlock handle nine coarse-grained actions: read, write, execute, new,
get, remove, ioctl, lock and fcntl. Each of them abstract LSM hook
access control in a way that can be extended in the future.

The Landlock LSM hook registration is done after other LSM to only run
actions from user-space, via eBPF programs, if the access was granted by
major (privileged) LSMs.

Signed-off-by: Mickaël Salaün <mic@digikod.net>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: David S. Miller <davem@davemloft.net>
Cc: James Morris <redacted>
Cc: Kees Cook <redacted>
Cc: Serge E. Hallyn <serge@hallyn.com>
---

Changes since v6:
* add 3 more sub-events: IOCTL, LOCK, FCNTL
  https://lkml.kernel.org/r/2fbc99a6-f190-f335-bd14-04bdeed35571@digikod.net
* use the new security_add_hooks()
* explain the -Werror=unused-function
* constify pointers
* cleanup headers

Changes since v5:
* split hooks.[ch] into hooks.[ch] and hooks_fs.[ch]
* add more documentation
* cosmetic fixes
* rebase (SCALAR_VALUE)

Changes since v4:
* add LSM hook abstraction called Landlock event
  * use the compiler type checking to verify hooks use by an event
  * handle all filesystem related LSM hooks (e.g. file_permission,
    mmap_file, sb_mount...)
* register BPF programs for Landlock just after LSM hooks registration
* move hooks registration after other LSMs
* add failsafes to check if a hook is not used by the kernel
* allow partial raw value access form the context (needed for programs
  generated by LLVM)

Changes since v3:
* split commit
* add hooks dealing with struct inode and struct path pointers:
  inode_permission and inode_getattr
* add abstraction over eBPF helper arguments thanks to wrapping structs
---
 include/linux/lsm_hooks.h    |   5 +
 security/landlock/Makefile   |   7 +-
 security/landlock/common.h   |   2 +
 security/landlock/hooks.c    |  83 ++++++
 security/landlock/hooks.h    | 177 +++++++++++++
 security/landlock/hooks_fs.c | 586 +++++++++++++++++++++++++++++++++++++++++++
 security/landlock/hooks_fs.h |  19 ++
 security/landlock/init.c     |  10 +
 security/security.c          |  12 +-
 9 files changed, 899 insertions(+), 2 deletions(-)
 create mode 100644 security/landlock/hooks.c
 create mode 100644 security/landlock/hooks.h
 create mode 100644 security/landlock/hooks_fs.c
 create mode 100644 security/landlock/hooks_fs.h

I forgot to handle LANDLOCK_SUBTYPE_EVENT_FS_{IOCTL,LOCK_FCNTL} here and
I included some hunks in the wrong patches. I will fix this in the next
series and add tests for those anyway. :)

Regards,
 Mickaël