lsm: rework lsm_active_cnt and lsm_idlist[]

Move the LSM active count and lsm_id list declarations out of a header
that is visible across the kernel and into a header that is limited to
the LSM framework. This not only helps keep the include/linux headers
smaller and cleaner, it helps prevent misuse of these variables.

Reviewed-by: Casey Schaufler <[e-mail]>
Reviewed-by: John Johansen <[e-mail]>
Reviewed-by: Mimi Zohar <[e-mail]>
Signed-off-by: Paul Moore <[e-mail]>

include/linux/security.h

···
 };
 
 extern const char *const lockdown_reasons[LOCKDOWN_CONFIDENTIALITY_MAX+1];
-extern u32 lsm_active_cnt;
-extern const struct lsm_id *lsm_idlist[];
 
 /* These functions are in security/commoncap.c */
 extern int cap_capable(const struct cred *cred, struct user_namespace *ns,

security/lsm.h

···
 #define _LSM_H_
 
 #include <linux/lsm_hooks.h>
+#include <linux/lsm_count.h>
+
+/* List of configured LSMs */
+extern unsigned int lsm_active_cnt;
+extern const struct lsm_id *lsm_idlist[];
 
 /* LSM blob configuration */
 extern struct lsm_blob_sizes blob_sizes;

security/lsm_init.c

···
 	}
 }
 
-/*
- * Current index to use while initializing the lsm id list.
- */
-u32 lsm_active_cnt __ro_after_init;
-const struct lsm_id *lsm_idlist[MAX_LSM_COUNT];
-
 /* Populate ordered LSMs list from comma-separated LSM name list. */
 static void __init ordered_lsm_parse(const char *order, const char *origin)
 {

security/lsm_syscalls.c

···
 #include <linux/lsm_hooks.h>
 #include <uapi/linux/lsm.h>
 
+#include "lsm.h"
+
 /**
  * lsm_name_to_attr - map an LSM attribute name to its ID
  * @name: name of the attribute

security/security.c

···
 	[LOCKDOWN_CONFIDENTIALITY_MAX] = "confidentiality",
 };
 
+unsigned int lsm_active_cnt __ro_after_init;
+const struct lsm_id *lsm_idlist[MAX_LSM_COUNT];
+
 struct lsm_blob_sizes blob_sizes;
 
 struct kmem_cache *lsm_file_cache;