Comments:
---------
Add class support to the role_transition rule so that it could be used in
a much more generalized manner.
So far the semantics of the role_transition rule does not support specifying
the class, and in SELinux kernel security server it could be applied to the
process class only.
With the class support the role_transition rule could be used for non-process
classes, and the newly created object could have roles other than "object_r",
which is a prerequisit for real RBAC separation development in the future.
Testings I've done:
-------------------
0. Add below snippet into sysadm.te for testing:
role_transition sysadm_r user_home_t:{ file dir lnk_file fifo_file sock_file chr_file blk_file } sysadm_r;
role sysadm_r types user_home_t;
gen_require(`
type vlock_exec_t, vlock_t;
')
role_transition sysadm_r vlock_exec_t system_r;
1. Verify that the dismod program could display the class field of the
role_transition rule correctly:
/work/selinux/selinux/checkpolicy$ test/dismod /work/selinux/refpolicy/sysadm.pp
Reading policy...
......
......
Command ('m' for menu): 7
role transitions:
--- begin avrule block ---
decl 1:
role transition sysadm_r [vlock_exec_t] : [process] system_r
role transition sysadm_r [user_home_t] :{ [file] [dir] [lnk_file] [chr_file] [blk_file] [sock_file] [fifo_file] } sysadm_r
--- begin avrule block ---
decl 2:
......
--- begin avrule block ---
decl 342:
Command ('m' for menu): q
/work/selinux/selinux/checkpolicy$
2. Further verify the binary reprensentation of the role_transition rule
are correct:
/work/selinux/refpolicy$ ls -lt /etc/selinux/refpolicy-mls/policy/policy.25
-rw-r--r--. 2 root root 5849742 2011-03-22 15:39 /etc/selinux/refpolicy-mls/policy/policy.25
/work/selinux/refpolicy$ xxd /etc/selinux/refpolicy-mls/policy/policy.25 > policy_25_xxd
/work/selinux/refpolicy$ vim policy_25_xxd
......
055c510: 0d00 l.....S.........
055c520: 0000 0300 0000 a006 0000 0200 0000 0b00 ................
055c530: 0000 0300 0000 a103 0000 0200 0000 0b00 ................
055c540: 0000 0800 0000 b707 0000 0200 0000 0b00 ................
055c550: 0000 0800 0000 a70a 0000 0200 0000 0b00 ................
055c560: 0000 0a00 0000 db00 0000 0200 0000 0b00 ................
055c570: 0000 0a00 0000 8e05 0000 0600 0000 0a00 ................
055c580: 0000 0a00 0000 8e05 0000 0700 0000 0a00 ................
055c590: 0000 0a00 0000 8e05 0000 0900 0000 0a00 ................
055c5a0: 0000 0a00 0000 8e05 0000 0a00 0000 0a00 ................
055c5b0: 0000 0a00 0000 8e05 0000 0b00 0000 0a00 ................
055c5c0: 0000 0a00 0000 8e05 0000 0c00 0000 0a00 ................
055c5d0: 0000 0a00 0000 8e05 0000 0d00 0000 0a00 ................
055c5e0: 0000 0c00 0000 9209 0000 0200 0000 0b00 ................
055c5f0: 0000
......
/work/selinux/refpolicy$
3. Run-time test one - verify that the role_transition rule works for
non-process classes:
[root/sysadm_r/s0@~]# sestatus
SELinux status: enabled
SELinuxfs mount: /selinux
Current mode: enforcing
Mode from config file: enforcing
Policy version: 25
Policy from config file: refpolicy-mls
[root/sysadm_r/s0@~]#
[root/sysadm_r/s0@~]# id -Z
root:sysadm_r:sysadm_t:s0-s15:c0.c1023
[root/sysadm_r/s0@~]# ls -Zd
dr-xr-x--- root root root:object_r:user_home_dir_t:s0-s15:c0.c1023 .
[root/sysadm_r/s0@~]#
[root/sysadm_r/s0@~]# compute_create root:sysadm_r:sysadm_t:s0-s15:c0.c1023 root:object_r:user_home_dir_t:s0-s15:c0.c1023 file
root:sysadm_r:user_home_t:s0
[root/sysadm_r/s0@~]# compute_create root:sysadm_r:sysadm_t:s0-s15:c0.c1023 root:object_r:user_home_dir_t:s0-s15:c0.c1023 dir
root:sysadm_r:user_home_t:s0
[root/sysadm_r/s0@~]#
[root/sysadm_r/s0@~]# mkdir dir
[root/sysadm_r/s0@~]# touch file
[root/sysadm_r/s0@~]#
[root/sysadm_r/s0@~]# ls -Zd dir file
drwxr-xr-x root root root:sysadm_r:user_home_t:s0 dir
-rw-r--r-- root root root:sysadm_r:user_home_t:s0 file
[root/sysadm_r/s0@~]#
4. Run-time test two - verify that the role_transition rule works for the
process class:
[root/sysadm_r/s0@~]# ls -Z /usr/sbin/vlock-main
-rws--x--x root root system_u:object_r:vlock_exec_t:s0 /usr/sbin/vlock-main
[root/sysadm_r/s0@~]#
[root/sysadm_r/s0@~]# compute_create root:staff_r:staff_t:s0-s15:c0.c1023 system_u:object_r:vlock_exec_t:s0 process
root:staff_r:vlock_t:s0-s15:c0.c1023
[root/sysadm_r/s0@~]#
[root/sysadm_r/s0@~]# compute_create root:sysadm_r:sysadm_t:s0-s15:c0.c1023 system_u:object_r:vlock_exec_t:s0 process
root:system_r:vlock_t:s0-s15:c0.c1023
[root/sysadm_r/s0@~]#
[root/staff_r/s0@~]# vlock &
[1] 796
[root/staff_r/s0@~]# ps Z -C vlock-main
LABEL PID TTY STAT TIME COMMAND
root:staff_r:vlock_t:s0-s15:c0.c1023 796 pts/0 T 0:00 /usr/sbin/vlock-main
[1]+ Stopped vlock
[root/staff_r/s0@~]#
[root/sysadm_r/s0@~]# seclow "setenforce 0"
Password:
[root/sysadm_r/s0@~]# vlock &
[1] 812
[root/sysadm_r/s0@~]# ps Z -C vlock-main
LABEL PID TTY STAT TIME COMMAND
root:staff_r:vlock_t:s0-s15:c0.c1023 796 pts/0 T 0:00 /usr/sbin/vlock-main
root:system_r:vlock_t:s0-s15:c0.c1023 812 ttyS0 T 0:00 /usr/sbin/vlock-main
[1]+ Stopped vlock
[root/sysadm_r/s0@~]#
(Note, "setenforce 0" is to shortcut the necessary user-role & role-type settings in sysadm.pp for system_r)
5. (TODO) restorecon doesn't take into account the role_transition rule
for non-process class so far:
[root/sysadm_r/s0@~]# ls -Zd dir file
drwxr-xr-x root root root:sysadm_r:user_home_t:s0 dir
-rw-r--r-- root root root:sysadm_r:user_home_t:s0 file
[root/sysadm_r/s0@~]#
[root/sysadm_r/s0@~]# restorecon dir file
[root/sysadm_r/s0@~]#
[root/sysadm_r/s0@~]# ls -Zd dir file
drwxr-xr-x root root root:object_r:user_home_t:s0 dir
-rw-r--r-- root root root:object_r:user_home_t:s0 file
[root/sysadm_r/s0@~]#
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