[RFC v2 00/10] snet: Security for NETwork syscalls

[Samir Bellabes <sam@synack.fr>]

Hello lsm and netdev people,
This set of patches is the version 2 of snet, which I would like to submit as a
RFC.

snet is a linux security module. It provides a mecanism defering syscall
security hooks and decision (verdict) to userspace. 

snet has some subsystems :
    - snet_core     : init and exit the system
    - snet_hooks    : LSM hooks
    - snet_netlink  : kernel-user communication (genetlink)
    - snet_event    : manages the list of protected syscalls
    - snet_verdict  : provides a waitqueue for syscalls and manage verdicts
    - snet_ticket   : provides a granted-access ticket mecanism

I believe that snet will help to get over the classical configuration
complexity of others security modules, by providing interactivity to users.
I also think that monolithic strategy is broken with snet, as we can provide
security for others syscall's categories:
 - sfs  : security for filesystem,
 - stask: security for task,
 - smem : security for memory
 ..

In this way, and by putting abstraction on how this subsystems can talk to each
others, we may use the security combinaison we want: choose to run sfs,
stask, but not snet nor smem. Better, developpers may investigated how to build
another security subsystem for tasks, and use others existing (smem, snet..)
which they don't want to modify

I think that interactivity is very usefull for users, as they may be notify when
something is wrong and take decision, and from userspace, the decision may be
defered to another box. In this way, snet also have a advantage for mobile
devices as the policy decision will be push to a distant server, mobile device
will then wait for verdicts and as policy strategies are centralized.

Finally, and a important point: snet integration respects the LSM framework idea
of using LSM hooks.

New feature from the previous version:
 * Building a ticket mecanism for each task_struct using pointer void *security
   Use the pointer (void*) security related to task_struct to provides
   granted-acces tickets: if two identical requests are coming, ask the user
   for the first one, store the result in a ticket and for the second request,
   just look in the tickets owned by the task-struct
 * send data buffer of sendmsg to userspace
   this may provide a way to look inside the data (as a anti-virus do)

roadmap:
 * find a way to send data buffer of sendmsg to userspace (using netfilter)
 * adding other security systems
   we can think about adding fork(), exec(), open(), close()..

I'm Ccing netfilter-devel, as snet may be seen as a way to do filtering.

Samir Bellabes (10):
  lsm: add security_socket_closed()
  Revert "lsm: Remove the socket_post_accept() hook"
  snet: introduce security/snet, Makefile and Kconfig changes
  snet: introduce snet_core
  snet: introduce snet_event
  snet: introduce snet_hooks
  snet: introduce snet_netlink
  snet: introduce snet_verdict
  snet: introduce snet_ticket
  snet: introduce snet_utils

 include/linux/security.h            |   23 ++
 include/linux/snet.h                |  120 ++++++
 net/socket.c                        |    3 +
 security/Kconfig                    |    6 +
 security/Makefile                   |    2 +
 security/capability.c               |   10 +
 security/security.c                 |   10 +
 security/snet/Kconfig               |   11 +
 security/snet/Makefile              |   14 +
 security/snet/snet_core.c           |   76 ++++
 security/snet/snet_event.c          |  189 ++++++++++
 security/snet/snet_event.h          |   21 +
 security/snet/snet_hooks.c          |  710 +++++++++++++++++++++++++++++++++++
 security/snet/snet_hooks.h          |   10 +
 security/snet/snet_netlink.c        |  431 +++++++++++++++++++++
 security/snet/snet_netlink.h        |   17 +
 security/snet/snet_netlink_helper.c |  230 +++++++++++
 security/snet/snet_netlink_helper.h |    7 +
 security/snet/snet_ticket.c         |  171 +++++++++
 security/snet/snet_ticket.h         |   37 ++
 security/snet/snet_ticket_helper.c  |  127 +++++++
 security/snet/snet_ticket_helper.h  |    8 +
 security/snet/snet_utils.c          |   38 ++
 security/snet/snet_utils.h          |   10 +
 security/snet/snet_verdict.c        |  184 +++++++++
 security/snet/snet_verdict.h        |   23 ++
 26 files changed, 2488 insertions(+), 0 deletions(-)
 create mode 100644 include/linux/snet.h
 create mode 100644 security/snet/Kconfig
 create mode 100644 security/snet/Makefile
 create mode 100644 security/snet/snet_core.c
 create mode 100644 security/snet/snet_event.c
 create mode 100644 security/snet/snet_event.h
 create mode 100644 security/snet/snet_hooks.c
 create mode 100644 security/snet/snet_hooks.h
 create mode 100644 security/snet/snet_netlink.c
 create mode 100644 security/snet/snet_netlink.h
 create mode 100644 security/snet/snet_netlink_helper.c
 create mode 100644 security/snet/snet_netlink_helper.h
 create mode 100644 security/snet/snet_ticket.c
 create mode 100644 security/snet/snet_ticket.h
 create mode 100644 security/snet/snet_ticket_helper.c
 create mode 100644 security/snet/snet_ticket_helper.h
 create mode 100644 security/snet/snet_utils.c
 create mode 100644 security/snet/snet_utils.h
 create mode 100644 security/snet/snet_verdict.c
 create mode 100644 security/snet/snet_verdict.h