[SECMARK]: Add new packet controls to SELinux

Add new per-packet access controls to SELinux, replacing the old
packet controls.

Packets are labeled with the iptables SECMARK and CONNSECMARK targets,
then security policy for the packets is enforced with these controls.

To allow for a smooth transition to the new controls, the old code is
still present, but not active by default.  To restore previous
behavior, the old controls may be activated at runtime by writing a
'1' to /selinux/compat_net, and also via the kernel boot parameter
selinux_compat_net.  Switching between the network control models
requires the security load_policy permission.  The old controls will
probably eventually be removed and any continued use is discouraged.

With this patch, the new secmark controls for SElinux are disabled by
default, so existing behavior is entirely preserved, and the user is
not affected at all.

It also provides a config option to enable the secmark controls by
default (which can always be overridden at boot and runtime).  It is
also noted in the kconfig help that the user will need updated
userspace if enabling secmark controls for SELinux and that they'll
probably need the SECMARK and CONNMARK targets, and conntrack protocol
helpers, although such decisions are beyond the scope of kernel
configuration.

Signed-off-by: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 29 insertions, 0 deletions

diff --git a/security/selinux/Kconfig b/security/selinux/Kconfig
index f636f53ca544..814ddc42f1f4 100644
--- a/security/selinux/Kconfig
+++ b/security/selinux/Kconfig
@@ -1,6 +1,7 @@
 config SECURITY_SELINUX
         bool "NSA SELinux Support"
         depends on SECURITY_NETWORK && AUDIT && NET && INET
+        select NETWORK_SECMARK
         default n
         help
           This selects NSA Security-Enhanced Linux (SELinux).
@@ -95,3 +96,31 @@ config SECURITY_SELINUX_CHECKREQPROT_VALUE
           via /selinux/checkreqprot if authorized by policy.
 
           If you are unsure how to answer this question, answer 1.
+
+config SECURITY_SELINUX_ENABLE_SECMARK_DEFAULT
+        bool "NSA SELinux enable new secmark network controls by default"
+        depends on SECURITY_SELINUX
+        default n
+        help
+          This option determines whether the new secmark-based network
+          controls will be enabled by default.  If not, the old internal
+          per-packet controls will be enabled by default, preserving
+          old behavior.
+
+          If you enable the new controls, you will need updated
+          SELinux userspace libraries, tools and policy.  Typically,
+          your distribution will provide these and enable the new controls
+          in the kernel they also distribute.
+
+          Note that this option can be overriden at boot with the
+          selinux_compat_net parameter, and after boot via
+          /selinux/compat_net.  See Documentation/kernel-parameters.txt
+          for details on this parameter.
+
+          If you enable the new network controls, you will likely
+          also require the SECMARK and CONNSECMARK targets, as
+          well as any conntrack helpers for protocols which you
+          wish to control.
+
+          If you are unsure what do do here, select N.
+