security: remove register_security hook

The register security hook is no longer required, as the capability
module is always registered.  LSMs wishing to stack capability as
a secondary module should do so explicitly.
Signed-off-by: James Morris <jmorris@namei.org>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>

include/linux/security.h

@@ -1239,11 +1239,6 @@ static inline void security_free_mnt_opts(struct security_mnt_opts *opts)
  *	@pages contains the number of pages.
  *	Return 0 if permission is granted.
  *
- * @register_security:
- *	allow module stacking.
- *	@name contains the name of the security module being stacked.
- *	@ops contains a pointer to the struct security_operations of the module to stack.
- *
  * @secid_to_secctx:
  *	Convert secid to security context.
  *	@secid contains the security ID.
@@ -1471,10 +1466,6 @@ struct security_operations {
 	int (*netlink_send) (struct sock *sk, struct sk_buff *skb);
 	int (*netlink_recv) (struct sk_buff *skb, int cap);
 
-	/* allow module stacking */
-	int (*register_security) (const char *name,
-				  struct security_operations *ops);
-
 	void (*d_instantiate) (struct dentry *dentry, struct inode *inode);
 
 	int (*getprocattr) (struct task_struct *p, char *name, char **value);
@@ -1564,7 +1555,6 @@ struct security_operations {
 extern int security_init(void);
 extern int security_module_enable(struct security_operations *ops);
 extern int register_security(struct security_operations *ops);
-extern int mod_reg_security(const char *name, struct security_operations *ops);
 extern struct dentry *securityfs_create_file(const char *name, mode_t mode,
 					     struct dentry *parent, void *data,
 					     const struct file_operations *fops);

security/capability.c

@@ -721,12 +721,6 @@ static int cap_xfrm_decode_session(struct sk_buff *skb, u32 *fl, int ckall)
 }
 
 #endif /* CONFIG_SECURITY_NETWORK_XFRM */
-static int cap_register_security(const char *name,
-				 struct security_operations *ops)
-{
-	return -EINVAL;
-}
-
 static void cap_d_instantiate(struct dentry *dentry, struct inode *inode)
 {
 }
@@ -940,7 +934,6 @@ void security_fixup_ops(struct security_operations *ops)
 	set_to_cap_if_null(ops, sem_semop);
 	set_to_cap_if_null(ops, netlink_send);
 	set_to_cap_if_null(ops, netlink_recv);
-	set_to_cap_if_null(ops, register_security);
 	set_to_cap_if_null(ops, d_instantiate);
 	set_to_cap_if_null(ops, getprocattr);
 	set_to_cap_if_null(ops, setprocattr);

security/root_plug.c

@@ -28,9 +28,6 @@
 #include <linux/usb.h>
 #include <linux/moduleparam.h>
 
-/* flag to keep track of how we were registered */
-static int secondary;
-
 /* default is a generic type of usb to serial converter */
 static int vendor_id = 0x0557;
 static int product_id = 0x2008;
@@ -97,13 +94,7 @@ static int __init rootplug_init (void)
 	if (register_security (&rootplug_security_ops)) {
 		printk (KERN_INFO 
 			"Failure registering Root Plug module with the kernel\n");
-		/* try registering with primary module */
-		if (mod_reg_security (MY_NAME, &rootplug_security_ops)) {
-			printk (KERN_INFO "Failure registering Root Plug "
-				" module with primary security module.\n");
 			return -EINVAL;
-		}
-		secondary = 1;
 	}
 	printk (KERN_INFO "Root Plug module initialized, "
 		"vendor_id = %4.4x, product id = %4.4x\n", vendor_id, product_id);

security/security.c

@@ -125,35 +125,6 @@ int register_security(struct security_operations *ops)
 	return 0;
 }
 
-/**
- * mod_reg_security - allows security modules to be "stacked"
- * @name: a pointer to a string with the name of the security_options to be registered
- * @ops: a pointer to the struct security_options that is to be registered
- *
- * This function allows security modules to be stacked if the currently loaded
- * security module allows this to happen.  It passes the @name and @ops to the
- * register_security function of the currently loaded security module.
- *
- * The return value depends on the currently loaded security module, with 0 as
- * success.
- */
-int mod_reg_security(const char *name, struct security_operations *ops)
-{
-	if (verify(ops)) {
-		printk(KERN_INFO "%s could not verify "
-		       "security operations.\n", __func__);
-		return -EINVAL;
-	}
-
-	if (ops == security_ops) {
-		printk(KERN_INFO "%s security operations "
-		       "already registered.\n", __func__);
-		return -EINVAL;
-	}
-
-	return security_ops->register_security(name, ops);
-}
-
 /* Security operations */
 
 int security_ptrace(struct task_struct *parent, struct task_struct *child,

security/selinux/hooks.c

@@ -126,13 +126,11 @@ __setup("selinux=", selinux_enabled_setup);
 int selinux_enabled = 1;
 #endif
 
-/* Original (dummy) security module. */
-static struct security_operations *original_ops;
 
-/* Minimal support for a secondary security module,
-   just to allow the use of the dummy or capability modules.
-   The owlsm module can alternatively be used as a secondary
-   module as long as CONFIG_OWLSM_FD is not enabled. */
+/*
+ * Minimal support for a secondary security module,
+ * just to allow the use of the capability module.
+ */
 static struct security_operations *secondary_ops;
 
 /* Lists of inode and superblock security structures initialized
@@ -5115,24 +5113,6 @@ static void selinux_ipc_getsecid(struct kern_ipc_perm *ipcp, u32 *secid)
 	*secid = isec->sid;
 }
 
-/* module stacking operations */
-static int selinux_register_security(const char *name, struct security_operations *ops)
-{
-	if (secondary_ops != original_ops) {
-		printk(KERN_ERR "%s:  There is already a secondary security "
-		       "module registered.\n", __func__);
-		return -EINVAL;
-	}
-
-	secondary_ops = ops;
-
-	printk(KERN_INFO "%s:  Registering secondary module %s\n",
-	       __func__,
-	       name);
-
-	return 0;
-}
-
 static void selinux_d_instantiate(struct dentry *dentry, struct inode *inode)
 {
 	if (inode)
@@ -5517,8 +5497,6 @@ static struct security_operations selinux_ops = {
 	.sem_semctl =			selinux_sem_semctl,
 	.sem_semop =			selinux_sem_semop,
 
-	.register_security =		selinux_register_security,
-
 	.d_instantiate =		selinux_d_instantiate,
 
 	.getprocattr =			selinux_getprocattr,
@@ -5612,7 +5590,7 @@ static __init int selinux_init(void)
 					    0, SLAB_PANIC, NULL);
 	avc_init();
 
-	original_ops = secondary_ops = security_ops;
+	secondary_ops = security_ops;
 	if (!secondary_ops)
 		panic("SELinux: No initial security operations\n");
 	if (register_security(&selinux_ops))

security/smack/smack_lsm.c

@@ -1822,27 +1822,6 @@ static void smack_ipc_getsecid(struct kern_ipc_perm *ipp, u32 *secid)
 	*secid = smack_to_secid(smack);
 }
 
-/* module stacking operations */
-
-/**
- * smack_register_security - stack capability module
- * @name: module name
- * @ops: module operations - ignored
- *
- * Allow the capability module to register.
- */
-static int smack_register_security(const char *name,
-				   struct security_operations *ops)
-{
-	if (strcmp(name, "capability") != 0)
-		return -EINVAL;
-
-	printk(KERN_INFO "%s:  Registering secondary module %s\n",
-	       __func__, name);
-
-	return 0;
-}
-
 /**
  * smack_d_instantiate - Make sure the blob is correct on an inode
  * @opt_dentry: unused
@@ -2673,8 +2652,6 @@ struct security_operations smack_ops = {
 	.netlink_send =			cap_netlink_send,
 	.netlink_recv = 		cap_netlink_recv,
 
-	.register_security = 		smack_register_security,
-
 	.d_instantiate = 		smack_d_instantiate,
 
 	.getprocattr = 			smack_getprocattr,