selinux: move policy mutex to selinux_state, use in lockdep checks

Move the mutex used to synchronize policy changes (reloads and setting
of booleans) from selinux_fs_info to selinux_state and use it in
lockdep checks for rcu_dereference_protected() calls in the security
server functions.  This makes the dependency on the mutex explicit
in the code rather than relying on comments.

Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Reviewed-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

1 files changed, 12 insertions, 14 deletions

diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c
index d1872adf0c47..29567acdda21 100644
--- a/security/selinux/selinuxfs.c
+++ b/security/selinux/selinuxfs.c
@@ -75,7 +75,6 @@ struct selinux_fs_info {
 	unsigned long last_class_ino;
 	bool policy_opened;
 	struct dentry *policycap_dir;
-	struct mutex mutex;
 	unsigned long last_ino;
 	struct selinux_state *state;
 	struct super_block *sb;
@@ -89,7 +88,6 @@ static int selinux_fs_info_create(struct super_block *sb)
 	if (!fsi)
 		return -ENOMEM;
 
-	mutex_init(&fsi->mutex);
 	fsi->last_ino = SEL_INO_NEXT - 1;
 	fsi->state = &selinux_state;
 	fsi->sb = sb;
@@ -400,7 +398,7 @@ static int sel_open_policy(struct inode *inode, struct file *filp)
 
 	BUG_ON(filp->private_data);
 
-	mutex_lock(&fsi->mutex);
+	mutex_lock(&fsi->state->policy_mutex);
 
 	rc = avc_has_perm(&selinux_state,
 			  current_sid(), SECINITSID_SECURITY,
@@ -431,11 +429,11 @@ static int sel_open_policy(struct inode *inode, struct file *filp)
 
 	filp->private_data = plm;
 
-	mutex_unlock(&fsi->mutex);
+	mutex_unlock(&fsi->state->policy_mutex);
 
 	return 0;
 err:
-	mutex_unlock(&fsi->mutex);
+	mutex_unlock(&fsi->state->policy_mutex);
 
 	if (plm)
 		vfree(plm->data);
@@ -622,7 +620,7 @@ static ssize_t sel_write_load(struct file *file, const char __user *buf,
 	ssize_t length;
 	void *data = NULL;
 
-	mutex_lock(&fsi->mutex);
+	mutex_lock(&fsi->state->policy_mutex);
 
 	length = avc_has_perm(&selinux_state,
 			      current_sid(), SECINITSID_SECURITY,
@@ -666,7 +664,7 @@ out1:
 		from_kuid(&init_user_ns, audit_get_loginuid(current)),
 		audit_get_sessionid(current));
 out:
-	mutex_unlock(&fsi->mutex);
+	mutex_unlock(&fsi->state->policy_mutex);
 	vfree(data);
 	return length;
 }
@@ -1271,7 +1269,7 @@ static ssize_t sel_read_bool(struct file *filep, char __user *buf,
 	unsigned index = file_inode(filep)->i_ino & SEL_INO_MASK;
 	const char *name = filep->f_path.dentry->d_name.name;
 
-	mutex_lock(&fsi->mutex);
+	mutex_lock(&fsi->state->policy_mutex);
 
 	ret = -EINVAL;
 	if (index >= fsi->bool_num || strcmp(name,
@@ -1290,14 +1288,14 @@ static ssize_t sel_read_bool(struct file *filep, char __user *buf,
 	}
 	length = scnprintf(page, PAGE_SIZE, "%d %d", cur_enforcing,
 			  fsi->bool_pending_values[index]);
-	mutex_unlock(&fsi->mutex);
+	mutex_unlock(&fsi->state->policy_mutex);
 	ret = simple_read_from_buffer(buf, count, ppos, page, length);
 out_free:
 	free_page((unsigned long)page);
 	return ret;
 
 out_unlock:
-	mutex_unlock(&fsi->mutex);
+	mutex_unlock(&fsi->state->policy_mutex);
 	goto out_free;
 }
 
@@ -1322,7 +1320,7 @@ static ssize_t sel_write_bool(struct file *filep, const char __user *buf,
 	if (IS_ERR(page))
 		return PTR_ERR(page);
 
-	mutex_lock(&fsi->mutex);
+	mutex_lock(&fsi->state->policy_mutex);
 
 	length = avc_has_perm(&selinux_state,
 			      current_sid(), SECINITSID_SECURITY,
@@ -1347,7 +1345,7 @@ static ssize_t sel_write_bool(struct file *filep, const char __user *buf,
 	length = count;
 
 out:
-	mutex_unlock(&fsi->mutex);
+	mutex_unlock(&fsi->state->policy_mutex);
 	kfree(page);
 	return length;
 }
@@ -1378,7 +1376,7 @@ static ssize_t sel_commit_bools_write(struct file *filep,
 	if (IS_ERR(page))
 		return PTR_ERR(page);
 
-	mutex_lock(&fsi->mutex);
+	mutex_lock(&fsi->state->policy_mutex);
 
 	length = avc_has_perm(&selinux_state,
 			      current_sid(), SECINITSID_SECURITY,
@@ -1400,7 +1398,7 @@ static ssize_t sel_commit_bools_write(struct file *filep,
 		length = count;
 
 out:
-	mutex_unlock(&fsi->mutex);
+	mutex_unlock(&fsi->state->policy_mutex);
 	kfree(page);
 	return length;
 }