securityfs: do not depend on CONFIG_SECURITY

Add a new Kconfig option SECURITYFS which will build securityfs support
but does not require CONFIG_SECURITY. The only current user of
securityfs does not depend on CONFIG_SECURITY and there is no reason the
full LSM needs to be built to build this fs.

Signed-off-by: Eric Paris <[e-mail]>
Signed-off-by: James Morris <[e-mail]>

drivers/char/tpm/Kconfig

···
 	tristate "TPM Hardware Support"
 	depends on HAS_IOMEM
 	depends on EXPERIMENTAL
+	select SECURITYFS
 	---help---
 	  If you have a TPM security chip in your system, which
 	  implements the Trusted Computing Group's specification,

include/linux/security.h

···
 extern int security_init(void);
 extern int security_module_enable(struct security_operations *ops);
 extern int register_security(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);
-extern struct dentry *securityfs_create_dir(const char *name, struct dentry *parent);
-extern void securityfs_remove(struct dentry *dentry);
 
 /* Security operations */
 int security_ptrace_may_access(struct task_struct *child, unsigned int mode);
···
 	return cap_netlink_recv(skb, cap);
 }
 
-static inline struct dentry *securityfs_create_dir(const char *name,
-					struct dentry *parent)
-{
-	return ERR_PTR(-ENODEV);
-}
-
-static inline struct dentry *securityfs_create_file(const char *name,
-						mode_t mode,
-						struct dentry *parent,
-						void *data,
-						const struct file_operations *fops)
-{
-	return ERR_PTR(-ENODEV);
-}
-
-static inline void securityfs_remove(struct dentry *dentry)
-{
-}
-
 static inline int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
 {
 	return -EOPNOTSUPP;
···
 
 #endif /* CONFIG_SECURITY */
 #endif /* CONFIG_AUDIT */
+
+#ifdef CONFIG_SECURITYFS
+
+extern struct dentry *securityfs_create_file(const char *name, mode_t mode,
+					     struct dentry *parent, void *data,
+					     const struct file_operations *fops);
+extern struct dentry *securityfs_create_dir(const char *name, struct dentry *parent);
+extern void securityfs_remove(struct dentry *dentry);
+
+#else /* CONFIG_SECURITYFS */
+
+static inline struct dentry *securityfs_create_dir(const char *name,
+						   struct dentry *parent)
+{
+	return ERR_PTR(-ENODEV);
+}
+
+static inline struct dentry *securityfs_create_file(const char *name,
+						    mode_t mode,
+						    struct dentry *parent,
+						    void *data,
+						    const struct file_operations *fops)
+{
+	return ERR_PTR(-ENODEV);
+}
+
+static inline void securityfs_remove(struct dentry *dentry)
+{}
+
+#endif
 
 #endif /* ! __LINUX_SECURITY_H */
 

security/Kconfig

···
 
 	  If you are unsure how to answer this question, answer N.
 
+config SECURITYFS
+	bool "Enable the securityfs filesystem"
+	help
+	  This will build the securityfs filesystem.  It is currently used by
+	  the TPM bios character driver.  It is not used by SELinux or SMACK.
+
+	  If you are unsure how to answer this question, answer N.
+
 config SECURITY_NETWORK
 	bool "Socket and Networking Security Hooks"
 	depends on SECURITY

security/Makefile

···
 obj-y		+= commoncap.o
 
 # Object file lists
-obj-$(CONFIG_SECURITY)			+= security.o capability.o inode.o
+obj-$(CONFIG_SECURITY)			+= security.o capability.o
+obj-$(CONFIG_SECURITYFS)		+= inode.o
 # Must precede capability.o in order to stack properly.
 obj-$(CONFIG_SECURITY_SELINUX)		+= selinux/built-in.o
 obj-$(CONFIG_SECURITY_SMACK)		+= smack/built-in.o