[PATCH v4 0/5] LSM: Add and use a hook for side-channel safety checks

[casey.schaufler@intel.com (Casey Schaufler)]

v4: select namespace checks if user namespaces are enabled
    and credential checks are request.
v3: get_task_cred wasn't a good choice due to refcounts.
    Use lower level protection instead
v2: SELinux access policy corrected.
    Use real_cred instead of cred.

This patchset provide a mechanism by which a security module
can advise the system about potential side-channel vulnerabilities.
If security_safe_sidechannel() returns 0 the security modules do
not know of any data that would be subject to a side-channel
attack. If the security module maintains data that it believes
may be susceptible to a side-channel attack it will return -EACCES.

Simple hooks are provided for SELinux and Smack. A new security
module is provided to make determinations regarding traditional
task attributes, including user IDs, capability sets and namespaces.

Signed-off-by: Casey Schaufler <casey.schaufler@intel.com>

---
 MAINTAINERS                        |   6 ++
 arch/x86/mm/tlb.c                  |  12 ++-
 include/linux/lsm_hooks.h          |  12 +++
 include/linux/security.h           |   1 +
 security/Kconfig                   |   1 +
 security/Makefile                  |   2 +
 security/security.c                |   6 ++
 security/selinux/hooks.c           |   9 ++
 security/sidechannel/Kconfig       |  65 +++++++++++++
 security/sidechannel/Makefile      |   1 +
 security/sidechannel/sidechannel.c | 184 +++++++++++++++++++++++++++++++++++++
 security/smack/smack_lsm.c         |  18 ++++
 12 files changed, 313 insertions(+), 4 deletions(-)