commit:     0458f4e2ec20f27f0cdc6a29c91e62bb65865075
Author:     Chris PeBenito <pebenito <AT> ieee <DOT> org>
AuthorDate: Fri Mar  5 21:06:44 2021 +0000
Commit:     Jason Zaman <perfinion <AT> gentoo <DOT> org>
CommitDate: Sun Mar 21 21:38:23 2021 +0000
URL:        
https://gitweb.gentoo.org/proj/hardened-refpolicy.git/commit/?id=0458f4e2

selinux: Add a secure_mode_setbool Boolean.

Enabling this will disable all permissions for setting SELinux Booleans,
even for unconfined domains.

This does not affect setenforce.  Enable secure_mode_policyload along with
secure_mode_setbool to fully lock the SELinux security interface.

Signed-off-by: Chris PeBenito <pebenito <AT> ieee.org>
Signed-off-by: Jason Zaman <perfinion <AT> gentoo.org>

 policy/modules/kernel/selinux.if | 19 +++++++++++++------
 policy/modules/kernel/selinux.te | 30 +++++++++++++++++++++++-------
 2 files changed, 36 insertions(+), 13 deletions(-)

diff --git a/policy/modules/kernel/selinux.if b/policy/modules/kernel/selinux.if
index 43eebcd0..21d22ded 100644
--- a/policy/modules/kernel/selinux.if
+++ b/policy/modules/kernel/selinux.if
@@ -392,14 +392,18 @@ interface(`selinux_read_policy',`
 interface(`selinux_set_generic_booleans',`
        gen_require(`
                type security_t;
+               bool secure_mode_setbool;
        ')
 
        dev_search_sysfs($1)
 
        allow $1 security_t:dir list_dir_perms;
-       allow $1 security_t:file rw_file_perms;
+       allow $1 security_t:file read_file_perms;
 
-       allow $1 security_t:security setbool;
+       if(!secure_mode_setbool) {
+               allow $1 security_t:file write_file_perms;
+               allow $1 security_t:security setbool;
+       }
 ')
 
 ########################################
@@ -428,18 +432,21 @@ interface(`selinux_set_all_booleans',`
        gen_require(`
                type security_t, secure_mode_policyload_t;
                attribute boolean_type;
-               bool secure_mode_policyload;
+               bool secure_mode_policyload, secure_mode_setbool;
        ')
 
        dev_search_sysfs($1)
 
        allow $1 security_t:dir list_dir_perms;
-       allow $1 { boolean_type -secure_mode_policyload_t }:file rw_file_perms;
+       allow $1 boolean_type:file read_file_perms;
        allow $1 secure_mode_policyload_t:file read_file_perms;
 
-       allow $1 security_t:security setbool;
+       if (!secure_mode_setbool) {
+               allow $1 security_t:security setbool;
+               allow $1 { boolean_type -secure_mode_policyload_t }:file 
write_file_perms;
+       }
 
-       if(!secure_mode_policyload) {
+       if(!secure_mode_policyload && !secure_mode_setbool) {
                allow $1 secure_mode_policyload_t:file write_file_perms;
        }
 ')

diff --git a/policy/modules/kernel/selinux.te b/policy/modules/kernel/selinux.te
index 3e4f2000..a1b4ae3e 100644
--- a/policy/modules/kernel/selinux.te
+++ b/policy/modules/kernel/selinux.te
@@ -7,13 +7,19 @@ policy_module(selinux, 1.18.0)
 
 ## <desc>
 ## <p>
-## Boolean to determine whether the system permits loading policy, setting
-## enforcing mode, and changing boolean values.  Set this to true and you
-## have to reboot to set it back.
+## Boolean to determine whether the system permits loading policy, and setting
+## enforcing mode.  Set this to true and you have to reboot to set it back.
 ## </p>
 ## </desc>
 gen_bool(secure_mode_policyload,false)
 
+## <desc>
+## <p>
+## Boolean to determine whether the system permits setting Booelan values.
+## </p>
+## </desc>
+gen_bool(secure_mode_setbool,false)
+
 attribute boolean_type;
 attribute can_load_policy;
 attribute can_setenforce;
@@ -91,12 +97,22 @@ dev_search_sysfs(can_setsecparam)
 allow selinux_unconfined_type security_t:dir list_dir_perms;
 allow selinux_unconfined_type security_t:file rw_file_perms;
 allow selinux_unconfined_type boolean_type:file read_file_perms;
-allow selinux_unconfined_type { boolean_type -secure_mode_policyload_t }:file 
write_file_perms;
 
 # Access the security API.
-allow selinux_unconfined_type security_t:security { compute_av compute_create 
compute_member check_context compute_relabel compute_user setbool setsecparam 
setcheckreqprot read_policy validate_trans };
+allow selinux_unconfined_type security_t:security { compute_av compute_create 
compute_member check_context compute_relabel compute_user setsecparam 
setcheckreqprot read_policy validate_trans };
 
-if(!secure_mode_policyload) {
+if (!secure_mode_policyload) {
        allow selinux_unconfined_type security_t:security { load_policy 
setenforce };
-       allow selinux_unconfined_type secure_mode_policyload_t:file 
write_file_perms;
+}
+
+if (!secure_mode_setbool) {
+       allow selinux_unconfined_type security_t:security setbool;
+}
+
+if (secure_mode_policyload && !secure_mode_setbool) {
+       allow selinux_unconfined_type { boolean_type -secure_mode_policyload_t 
}:file write_file_perms;
+}
+
+if (!secure_mode_policyload && !secure_mode_setbool) {
+       allow selinux_unconfined_type boolean_type:file write_file_perms;
 }

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