selinux: wrap global selinux state

Define a selinux state structure (struct selinux_state) for
global SELinux state and pass it explicitly to all security server
functions.  The public portion of the structure contains state
that is used throughout the SELinux code, such as the enforcing mode.
The structure also contains a pointer to a selinux_ss structure whose
definition is private to the security server and contains security
server specific state such as the policy database and SID table.

This change should have no effect on SELinux behavior or APIs
(userspace or LSM).  It merely wraps SELinux state and passes it
explicitly as needed.

Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
[PM: minor fixups needed due to collisions with the SCTP patches]
Signed-off-by: Paul Moore <paul@paul-moore.com>

1 files changed, 24 insertions, 23 deletions

diff --git a/security/selinux/ss/status.c b/security/selinux/ss/status.c
index d982365f9d1a..043efc59f8e4 100644
--- a/security/selinux/ss/status.c
+++ b/security/selinux/ss/status.c
@@ -35,8 +35,6 @@
  * In most cases, application shall confirm the kernel status is not
  * changed without any system call invocations.
  */
-static struct page *selinux_status_page;
-static DEFINE_MUTEX(selinux_status_lock);
 
 /*
  * selinux_kernel_status_page
@@ -44,21 +42,21 @@ static DEFINE_MUTEX(selinux_status_lock);
  * It returns a reference to selinux_status_page. If the status page is
  * not allocated yet, it also tries to allocate it at the first time.
  */
-struct page *selinux_kernel_status_page(void)
+struct page *selinux_kernel_status_page(struct selinux_state *state)
 {
 	struct selinux_kernel_status   *status;
 	struct page		       *result = NULL;
 
-	mutex_lock(&selinux_status_lock);
-	if (!selinux_status_page) {
-		selinux_status_page = alloc_page(GFP_KERNEL|__GFP_ZERO);
+	mutex_lock(&state->ss->status_lock);
+	if (!state->ss->status_page) {
+		state->ss->status_page = alloc_page(GFP_KERNEL|__GFP_ZERO);
 
-		if (selinux_status_page) {
-			status = page_address(selinux_status_page);
+		if (state->ss->status_page) {
+			status = page_address(state->ss->status_page);
 
 			status->version = SELINUX_KERNEL_STATUS_VERSION;
 			status->sequence = 0;
-			status->enforcing = selinux_enforcing;
+			status->enforcing = is_enforcing(state);
 			/*
 			 * NOTE: the next policyload event shall set
 			 * a positive value on the status->policyload,
@@ -66,11 +64,12 @@ struct page *selinux_kernel_status_page(void)
 			 * So, application can know it was updated.
 			 */
 			status->policyload = 0;
-			status->deny_unknown = !security_get_allow_unknown();
+			status->deny_unknown =
+				!security_get_allow_unknown(state);
 		}
 	}
-	result = selinux_status_page;
-	mutex_unlock(&selinux_status_lock);
+	result = state->ss->status_page;
+	mutex_unlock(&state->ss->status_lock);
 
 	return result;
 }
@@ -80,13 +79,14 @@ struct page *selinux_kernel_status_page(void)
  *
  * It updates status of the current enforcing/permissive mode.
  */
-void selinux_status_update_setenforce(int enforcing)
+void selinux_status_update_setenforce(struct selinux_state *state,
+				      int enforcing)
 {
 	struct selinux_kernel_status   *status;
 
-	mutex_lock(&selinux_status_lock);
-	if (selinux_status_page) {
-		status = page_address(selinux_status_page);
+	mutex_lock(&state->ss->status_lock);
+	if (state->ss->status_page) {
+		status = page_address(state->ss->status_page);
 
 		status->sequence++;
 		smp_wmb();
@@ -96,7 +96,7 @@ void selinux_status_update_setenforce(int enforcing)
 		smp_wmb();
 		status->sequence++;
 	}
-	mutex_unlock(&selinux_status_lock);
+	mutex_unlock(&state->ss->status_lock);
 }
 
 /*
@@ -105,22 +105,23 @@ void selinux_status_update_setenforce(int enforcing)
  * It updates status of the times of policy reloaded, and current
  * setting of deny_unknown.
  */
-void selinux_status_update_policyload(int seqno)
+void selinux_status_update_policyload(struct selinux_state *state,
+				      int seqno)
 {
 	struct selinux_kernel_status   *status;
 
-	mutex_lock(&selinux_status_lock);
-	if (selinux_status_page) {
-		status = page_address(selinux_status_page);
+	mutex_lock(&state->ss->status_lock);
+	if (state->ss->status_page) {
+		status = page_address(state->ss->status_page);
 
 		status->sequence++;
 		smp_wmb();
 
 		status->policyload = seqno;
-		status->deny_unknown = !security_get_allow_unknown();
+		status->deny_unknown = !security_get_allow_unknown(state);
 
 		smp_wmb();
 		status->sequence++;
 	}
-	mutex_unlock(&selinux_status_lock);
+	mutex_unlock(&state->ss->status_lock);
 }