[PATCH security-next v2 13/26] LSM: Plumb visibility into optional "enabled" state

[Kees Cook]

In preparation for lifting the "is this LSM enabled?" logic out of the
individual LSMs, pass in any special enabled state tracking (as needed
for SELinux, AppArmor, and LoadPin). This must be an "int" to include
handling cases where "enabled" is exposed via sysctl which has no "bool"
type (i.e. LoadPin's use).

LoadPin's "enabled" tracking will be added later when it gets added to
the "ordered LSM" stack.

Signed-off-by: Kees Cook <keescook at chromium.org>
---
 include/linux/lsm_hooks.h | 1 +
 security/apparmor/lsm.c   | 5 +++--
 security/selinux/hooks.c  | 1 +
 3 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index 38cbefabff71..118e12f678df 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -2044,6 +2044,7 @@ extern void security_add_hooks(struct security_hook_list *hooks, int count,
 struct lsm_info {
 	const char *name;	/* Populated automatically. */
 	unsigned long flags;	/* Optional: flags describing LSM */
+	int *enabled;		/* Optional: NULL means enabled. */
 	int (*init)(void);
 };
 
diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
index 4c5f63e9aeba..d03133a267f2 100644
--- a/security/apparmor/lsm.c
+++ b/security/apparmor/lsm.c
@@ -1303,8 +1303,8 @@ bool aa_g_paranoid_load = true;
 module_param_named(paranoid_load, aa_g_paranoid_load, aabool, S_IRUGO);
 
 /* Boot time disable flag */
-static bool apparmor_enabled = CONFIG_SECURITY_APPARMOR_BOOTPARAM_VALUE;
-module_param_named(enabled, apparmor_enabled, bool, S_IRUGO);
+static int apparmor_enabled = CONFIG_SECURITY_APPARMOR_BOOTPARAM_VALUE;
+module_param_named(enabled, apparmor_enabled, int, 0444);
 
 static int __init apparmor_enabled_setup(char *str)
 {
@@ -1608,5 +1608,6 @@ static int __init apparmor_init(void)
 
 DEFINE_LSM(apparmor)
 	.flags = LSM_FLAG_LEGACY_MAJOR,
+	.enabled = &apparmor_enabled,
 	.init = apparmor_init,
 END_LSM;
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 615cf6498c0f..3f999ed98cfd 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -7204,6 +7204,7 @@ void selinux_complete_init(void)
    all processes and objects when they are created. */
 DEFINE_LSM(selinux)
 	.flags = LSM_FLAG_LEGACY_MAJOR,
+	.enabled = &selinux_enabled,
 	.init = selinux_init,
 END_LSM;
 
-- 
2.17.1