TOMOYO: Don't create securityfs entries unless registered.

TOMOYO should not create /sys/kernel/security/tomoyo/ interface unless
TOMOYO is registered.
Signed-off-by: NKentaro Takeda <takedakn@nttdata.co.jp>
Signed-off-by: NTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: NToshiharu Harada <haradats@nttdata.co.jp>
Signed-off-by: NJames Morris <jmorris@namei.org>

security/tomoyo/common.c

@@ -2177,6 +2177,10 @@ static int __init tomoyo_initerface_init(void)
 {
 	struct dentry *tomoyo_dir;
 
+	/* Don't create securityfs entries unless registered. */
+	if (current_cred()->security != &tomoyo_kernel_domain)
+		return 0;
+
 	tomoyo_dir = securityfs_create_dir("tomoyo", NULL);
 	tomoyo_create_entry("domain_policy",    0600, tomoyo_dir,
 			    TOMOYO_DOMAINPOLICY);