Security: add static to security_ops and default_security_ops variable

Enhance the security framework to support resetting the active security
module. This eliminates the need for direct use of the security_ops and
default_security_ops variables outside of security.c, so make security_ops
and default_security_ops static. Also remove the secondary_ops variable as
a cleanup since there is no use for that. secondary_ops was originally used by
SELinux to call the "secondary" security module (capability or dummy),
but that was replaced by direct calls to capability and the only
remaining use is to save and restore the original security ops pointer
value if SELinux is disabled by early userspace based on /etc/selinux/config.
Further, if we support this directly in the security framework, then we can
just use &default_security_ops for this purpose since that is now available.

Signed-off-by: Zhitong Wang <zhitong.wangzt@alibaba-inc.com>
Acked-by:  Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>

1 files changed, 1 insertions, 12 deletions

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 6b36ce2eef2e..dc7660074b99 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -126,13 +126,6 @@ __setup("selinux=", selinux_enabled_setup);
 int selinux_enabled = 1;
 #endif
 
-
-/*
- * 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
    before the policy was loaded. */
 static LIST_HEAD(superblock_security_head);
@@ -5674,9 +5667,6 @@ static __init int selinux_init(void)
                                             0, SLAB_PANIC, NULL);
         avc_init();
 
-        secondary_ops = security_ops;
-        if (!secondary_ops)
-                panic("SELinux: No initial security operations\n");
         if (register_security(&selinux_ops))
                 panic("SELinux: Unable to register with kernel.\n");
 
@@ -5837,8 +5827,7 @@ int selinux_disable(void)
         selinux_disabled = 1;
         selinux_enabled = 0;
 
-        /* Reset security_ops to the secondary module, dummy or capability. */
-        security_ops = secondary_ops;
+        reset_security_ops();
 
         /* Try to destroy the avc node cache */
         avc_disable();