This removes CONFIG_DEFAULT_SECURITY in favor of the explicit ordering
offered by CONFIG_LSM and adds all the exclusive LSMs to the ordered
LSM initialization. The old meaning of CONFIG_DEFAULT_SECURITY is now
captured by which exclusive LSM is listed first in the LSM order. All
LSMs not added to the ordered list are explicitly disabled.

Signed-off-by: Kees Cook <keesc...@chromium.org>
---
 security/Kconfig    | 39 +--------------------------------------
 security/security.c | 35 ++++++++++-------------------------
 2 files changed, 11 insertions(+), 63 deletions(-)

diff --git a/security/Kconfig b/security/Kconfig
index 0aa82c1c928e..2f8dc1f59cae 100644
--- a/security/Kconfig
+++ b/security/Kconfig
@@ -239,46 +239,9 @@ source security/yama/Kconfig
 
 source security/integrity/Kconfig
 
-choice
-       prompt "Default security module"
-       default DEFAULT_SECURITY_SELINUX if SECURITY_SELINUX
-       default DEFAULT_SECURITY_SMACK if SECURITY_SMACK
-       default DEFAULT_SECURITY_TOMOYO if SECURITY_TOMOYO
-       default DEFAULT_SECURITY_APPARMOR if SECURITY_APPARMOR
-       default DEFAULT_SECURITY_DAC
-
-       help
-         Select the security module that will be used by default if the
-         kernel parameter security= is not specified.
-
-       config DEFAULT_SECURITY_SELINUX
-               bool "SELinux" if SECURITY_SELINUX=y
-
-       config DEFAULT_SECURITY_SMACK
-               bool "Simplified Mandatory Access Control" if SECURITY_SMACK=y
-
-       config DEFAULT_SECURITY_TOMOYO
-               bool "TOMOYO" if SECURITY_TOMOYO=y
-
-       config DEFAULT_SECURITY_APPARMOR
-               bool "AppArmor" if SECURITY_APPARMOR=y
-
-       config DEFAULT_SECURITY_DAC
-               bool "Unix Discretionary Access Controls"
-
-endchoice
-
-config DEFAULT_SECURITY
-       string
-       default "selinux" if DEFAULT_SECURITY_SELINUX
-       default "smack" if DEFAULT_SECURITY_SMACK
-       default "tomoyo" if DEFAULT_SECURITY_TOMOYO
-       default "apparmor" if DEFAULT_SECURITY_APPARMOR
-       default "" if DEFAULT_SECURITY_DAC
-
 config LSM
        string "Ordered list of enabled LSMs"
-       default "integrity"
+       default "integrity,selinux,smack,tomoyo,apparmor"
        help
          A comma-separated list of LSMs, in initialization order.
          Any LSMs left off this list will be ignored. This can be
diff --git a/security/security.c b/security/security.c
index 65f1fa733e4b..4f52bd06705f 100644
--- a/security/security.c
+++ b/security/security.c
@@ -175,8 +175,7 @@ static void __init ordered_lsm_parse(const char *order, 
const char *origin)
                bool found = false;
 
                for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) {
-                       if ((lsm->flags & LSM_FLAG_LEGACY_MAJOR) == 0 &&
-                           strcmp(lsm->name, name) == 0) {
+                       if (strcmp(lsm->name, name) == 0) {
                                append_ordered_lsm(lsm, origin);
                                found = true;
                        }
@@ -185,6 +184,15 @@ static void __init ordered_lsm_parse(const char *order, 
const char *origin)
                if (!found)
                        init_debug("%s ignored: %s\n", origin, name);
        }
+
+       /* Disable all LSMs not in the ordered list. */
+       for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) {
+               if (exists_ordered_lsm(lsm))
+                       continue;
+               set_enabled(lsm, false);
+               init_debug("%s disabled: %s\n", origin, lsm->name);
+       }
+
        kfree(sep);
 }
 
@@ -196,8 +204,6 @@ static void __init ordered_lsm_init(void)
                                GFP_KERNEL);
 
        /* Process "security=", if given. */
-       if (!chosen_major_lsm)
-               chosen_major_lsm = CONFIG_DEFAULT_SECURITY;
        if (chosen_major_lsm) {
                struct lsm_info *major;
 
@@ -229,22 +235,6 @@ static void __init ordered_lsm_init(void)
        kfree(ordered_lsms);
 }
 
-static void __init major_lsm_init(void)
-{
-       struct lsm_info *lsm;
-
-       for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) {
-               if ((lsm->flags & LSM_FLAG_LEGACY_MAJOR) == 0)
-                       continue;
-
-               /* Enable this LSM, if it is not already set. */
-               if (!lsm->enabled)
-                       lsm->enabled = &lsm_enabled_true;
-
-               maybe_initialize_lsm(lsm);
-       }
-}
-
 /**
  * security_init - initializes the security framework
  *
@@ -271,11 +261,6 @@ int __init security_init(void)
        /* Load LSMs in specified order. */
        ordered_lsm_init();
 
-       /*
-        * Load all the remaining security modules.
-        */
-       major_lsm_init();
-
        return 0;
 }
 
-- 
2.17.1

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