10:27 p.m.
Hi Bill,
Good news.
The "+" will add to any existing categories already given to the login,
which in your initial case was SystemLow-SystemHigh, so had no effect. If
it was initially SystemLow then it would have done the desired thing.
For platforms newer than CentOS6/RHEL6, then you can make the user_t domain
MCS constrained with:
[root@laptop ~]# cat mcsconstrainedusers.te
policy_module(mcsconstrainedusers, 1.0.0)
gen_require(`
type user_t;
')
mcs_constrained(user_t);
Compiling this under Fedora 25 gave a bunch of warnings, but the module
installed OK and gave the desired effect. I've not had time to look into
the warnings, sorry.
[root@laptop ~]# make -f /usr/share/selinux/devel/Makefile
/usr/share/selinux/devel/include/contrib/container.if:14: Error: duplicate
definition of container_runtime_domtrans(). Original definition on 14.
/usr/share/selinux/devel/include/contrib/container.if:40: Error: duplicate
definition of container_runtime_run(). Original definition on 40.
<snip>...
/usr/share/selinux/devel/include/contrib/container.if:589: Error: duplicate
definition of docker_spc_stream_connect(). Original definition on 589.
/usr/share/selinux/devel/include/contrib/container.if:603: Error: duplicate
definition of container_spc_read_state(). Original definition on 603.
Compiling targeted mcsconstrainedusers module
/usr/bin/checkmodule: loading policy configuration from
tmp/mcsconstrainedusers.tmp
/usr/bin/checkmodule: policy configuration loaded
/usr/bin/checkmodule: writing binary representation (version 17) to
tmp/mcsconstrainedusers.mod
Creating targeted mcsconstrainedusers.pp policy package
rm tmp/mcsconstrainedusers.mod tmp/mcsconstrainedusers.mod.fc
[root@laptop ~]# semodule -i mcsconstrainedusers.pp
[root@laptop ~]#
Cheers
Phil
From: Bill Durant <littus(a)icloud.com>
To: Philip Seeley <pseeley(a)au1.ibm.com>
Cc: littus(a)icloud.com, selinux(a)lists.fedoraproject.org
Date: 30/05/2017 07:01
Subject: Re: Controlling execution of Java JAR files with SELinux RBAC
Hello Phil:
Setting the categories instead of adding them with the "+" worked!
So it sounds like the chcat "+" option is not working as expected on CentOS
6.9. Do you concur?
Thank you for your help Phil.
The following series of steps show that it now works as expected:
# uname -a
Linux es300h 2.6.32-696.1.1.el6.x86_64 #1 SMP Tue Apr 11 17:13:24 UTC 2017
x86_64 x86_64 x86_64 GNU/Linux
# cat /etc/redhat-release
CentOS release 6.9 (Final)
# semanage user -l
Labeling MLS/ MLS/
SELinux User Prefix MCS Level MCS Range
SELinux Roles
git_shell_u user s0 s0
git_shell_r
green_u user s0 s0
green_r
guest_u user s0 s0
guest_r
red_u user s0 s0 red_r
root user s0 s0-s0:c0.c1023
staff_r sysadm_r system_r unconfined_r
staff_u user s0 s0-s0:c0.c1023
staff_r sysadm_r system_r unconfined_r
sysadm_u user s0 s0-s0:c0.c1023
sysadm_r
system_u user s0 s0-s0:c0.c1023
system_r unconfined_r
unconfined_u user s0 s0-s0:c0.c1023
system_r unconfined_r
user_u user s0 s0 user_r
xguest_u user s0 s0
xguest_r
# semanage user -m -r s0-s0:c0.c1023 user_u
# semanage user -l
Labeling MLS/ MLS/
SELinux User Prefix MCS Level MCS Range
SELinux Roles
git_shell_u user s0 s0
git_shell_r
green_u user s0 s0
green_r
guest_u user s0 s0
guest_r
red_u user s0 s0 red_r
root user s0 s0-s0:c0.c1023
staff_r sysadm_r system_r unconfined_r
staff_u user s0 s0-s0:c0.c1023
staff_r sysadm_r system_r unconfined_r
sysadm_u user s0 s0-s0:c0.c1023
sysadm_r
system_u user s0 s0-s0:c0.c1023
system_r unconfined_r
unconfined_u user s0 s0-s0:c0.c1023
system_r unconfined_r
user_u user s0 s0-s0:c0.c1023 user_r
xguest_u user s0 s0
xguest_r
# cat /etc/selinux/targeted/setrans.conf
#
# Multi-Category Security translation table for SELinux
#
# Uncomment the following to disable translation libary
# disable=1
#
# Objects can be categorized with 0-1023 categories defined by the admin.
# Objects can be in more than one category at a time.
# Categories are stored in the system as c0-c1023. Users can use this
# table to translate the categories into a more meaningful output.
# Examples:
# s0:c0=CompanyConfidential
# s0:c1=PatientRecord
# s0:c2=Unclassified
# s0:c3=TopSecret
# s0:c1,c3=CompanyConfidentialRedHat
s0:c0=NetworkAdministrator
s0:c1=Operator
s0=SystemLow
s0-s0:c0.c1023=SystemLow-SystemHigh
s0:c0.c1023=SystemHigh
# service mcstrans restart
Stopping mcstransd: [ OK ]
Starting mcstransd: [ OK ]
# chcat -L
s0:c0 NetworkAdministrator
s0:c1 Operator
s0 SystemLow
s0-s0:c0.c1023 SystemLow-SystemHigh
s0:c0.c1023 SystemHigh
# useradd foo
# useradd bar
# passwd foo
Changing password for user foo.
New password:
Retype new password:
passwd: all authentication tokens updated successfully.
# passwd bar
Changing password for user bar.
New password:
Retype new password:
passwd: all authentication tokens updated successfully.
# semanage login -a foo
# semanage login -a bar
# chcat -l -- c0 foo
# chcat -l -- c1 bar
# semanage login -l
Login Name SELinux User MLS/MCS
Range
__default__ unconfined_u
SystemLow-SystemHigh
bar user_u
SystemLow-Operator
foo user_u
SystemLow-NetworkAdministrator
root unconfined_u
SystemLow-SystemHigh
system_u system_u
SystemLow-SystemHigh
# chcat -L -l foo bar
foo: NetworkAdministrator
bar: Operator
# chcat -- +NetworkAdministrator /usr/local/soup/bin/foo.jar
# ls -Z /usr/local/soup/bin/foo.jar
-rwxr-xr-x. admin admin
system_u:object_r:bin_t:NetworkAdministrator /usr/local/soup/bin/foo.jar
Now as the Linux user, foo, it works as expected:
$ whoami
foo
$ id -Z
user_u:user_r:user_t:SystemLow-NetworkAdministrator
$ java -jar /usr/local/soup/bin/foo.jar
Hello from the foo application
Now as the Linux user, bar, it also works as expected:
$ whoami
bar
$ id -Z
user_u:user_r:user_t:SystemLow-Operator
$ java -jar /usr/local/soup/bin/foo.jar
Error: Unable to access jarfile /usr/local/soup/bin/foo.jar
Regards,
Bill
On 05/28/2017 05:22 PM, Philip Seeley wrote:
Hi Bill,
I saw in a previous post that you were using CentOS 6.9 so this
should work for you. It looks like the login configuration is not
quite right as both users are showing SystemLow-SystemHigh when they
logon.
Check the login config shows they only have the categories they need,
i.e. jack has c0 and mary has c1.
If they're not correct try setting the categories rather than adding
to them with a "+":
[root@centos6 ~]# chcat -l -- c0 jack
[root@centos6 ~]# chcat -l -- c1 mary
[root@centos6 ~]# semanage login -l
Login Name SELinux User MLS/MCS Range
__default__ unconfined_u s0-s0:c0.c1023
jack user_u s0-s0:c0
mary user_u s0-s0:c1
root unconfined_u s0-s0:c0.c1023
system_u system_u s0-s0:c0.c1023
Then with:
# ll -Z /usr/local/bin/
-rw-r--r--. root root unconfined_u:object_r:bin_t:s0:c0 jack
-rw-r--r--. root root unconfined_u:object_r:bin_t:s0:c1 mary
[root@centos6 ~]# cat /etc/system-release
CentOS release 6.9 (Final)
as jack:
[jack@centos6 ~]$ id
uid=500(jack) gid=500(jack) groups=500(jack)
context=user_u:user_r:user_t:s0-s0:c0
[jack@centos6 ~]$ cat /usr/local/bin/jack
Hi
[jack@centos6 ~]$ cat /usr/local/bin/mary
cat: /usr/local/bin/mary: Permission denied
and as mary:
[mary@centos6 ~]$ id
uid=501(mary) gid=501(mary) groups=501(mary)
context=user_u:user_r:user_t:s0-s0:c1
[mary@centos6 ~]$ cat /usr/local/bin/jack
cat: /usr/local/bin/jack: Permission denied
[mary@centos6 ~]$ cat /usr/local/bin/mary
Hi
Cheers
Phil
Inactive
hide details for Bill D ---26/05/2017
05:19:44---Hello Phil:
Thank you for the response. Your
suggested fix resolved Bill D ---26/05/2017 05:19:44---Hello Phil:
Thank you for the response. Your suggested fix resolved the error.
From: Bill D <littus(a)icloud.com>
To: Philip Seeley <pseeley(a)au1.ibm.com>
Cc: littus(a)icloud.com, selinux(a)lists.fedoraproject.org
Date: 26/05/2017 05:19
Subject: Re: Controlling execution of Java JAR files with SELinux
RBAC
Hello Phil:
Thank you for the response. Your suggested fix resolved the error.
However, I am unable to get the desired effect.
I am not able to prevent a Linux user from running/accessing a Java
JAR file using SELinux categories.
I would appreciate any other hints to make this work.
Following are the details of what I did:
# semanage user -l
Labeling MLS/ MLS/
SELinux User Prefix MCS Level MCS Range
SELinux Roles
git_shell_u user SystemLow SystemLow
git_shell_r
guest_u user SystemLow SystemLow
guest_r
root user SystemLow SystemLow-SystemHigh
staff_r sysadm_r system_r unconfined_r
staff_u user SystemLow SystemLow-SystemHigh
staff_r sysadm_r system_r unconfined_r
sysadm_u user SystemLow SystemLow-SystemHigh
sysadm_r
system_u user SystemLow SystemLow-SystemHigh
system_r unconfined_r
unconfined_u user SystemLow SystemLow-SystemHigh
system_r unconfined_r
user_u user SystemLow SystemLow
user_r
xguest_u user SystemLow SystemLow
xguest_r
# semanage user -m -r s0-s0:c0.c1023 user_u
# semanage user -l
Labeling MLS/ MLS/
SELinux User Prefix MCS Level MCS Range
SELinux Roles
git_shell_u user SystemLow SystemLow
git_shell_r
guest_u user SystemLow SystemLow
guest_r
root user SystemLow SystemLow-SystemHigh
staff_r sysadm_r system_r unconfined_r
staff_u user SystemLow SystemLow-SystemHigh
staff_r sysadm_r system_r unconfined_r
sysadm_u user SystemLow SystemLow-SystemHigh
sysadm_r
system_u user SystemLow SystemLow-SystemHigh
system_r unconfined_r
unconfined_u user SystemLow SystemLow-SystemHigh
system_r unconfined_r
user_u user SystemLow SystemLow-SystemHigh
user_r
xguest_u user SystemLow SystemLow
xguest_r
# cat setrans.conf
#
# Multi-Category Security translation table for SELinux
#
# Uncomment the following to disable translation libary
# disable=1
#
# Objects can be categorized with 0-1023 categories defined by the
admin.
# Objects can be in more than one category at a time.
# Categories are stored in the system as c0-c1023. Users can use
this
# table to translate the categories into a more meaningful output.
# Examples:
# s0:c0=CompanyConfidential
# s0:c1=PatientRecord
# s0:c2=Unclassified
# s0:c3=TopSecret
# s0:c1,c3=CompanyConfidentialRedHat
s0:c0=NetworkAdministrator
s0:c1=Operator
s0=SystemLow
s0-s0:c0.c1023=SystemLow-SystemHigh
s0:c0.c1023=SystemHigh
# service mcstrans restart
Stopping mcstransd: [ OK ]
Starting mcstransd: [ OK ]
# chcat -L
s0:c0 NetworkAdministrator
s0:c1 Operator
s0 SystemLow
s0-s0:c0.c1023 SystemLow-SystemHigh
s0:c0.c1023 SystemHigh
# useradd foo
# useradd bar
# passwd foo
Changing password for user foo.
New password:
Retype new password:
passwd: all authentication tokens updated successfully.
# passwd bar
Changing password for user bar.
New password:
Retype new password:
passwd: all authentication tokens updated successfully.
# semanage login -a foo
# semanage login -a bar
# chcat -l -- +NetworkAdministrator foo
# chcat -l -- +Operator bar
# chcat -L -l bar foo
bar: s0:c0.c1023,c1 <===== why is it not just s0:c1?
foo: s0:c0.c1023,c0 <===== why is it not just just s0:c0?
# chcat -- +NetworkAdministrator /usr/local/soup/bin/Foo.jar
# ls -Z /usr/local/soup/bin/Foo.jar
-rwxr-xr-x. admin admin
system_u:object_r:bin_t:NetworkAdministrator /usr/local/soup/bin/Foo.jar
Now Login as the 'foo' Linux user and notice that it can run Foo.jar
as expected
$ whoami
foo
$ id -Z
user_u:user_r:user_t:SystemLow-SystemHigh
$ ls -Z /usr/local/soup/bin/Foo.jar
-rwxr-xr-x. admin admin
system_u:object_r:bin_t:NetworkAdministrator /usr/local/soup/bin/Foo.jar
$ java -jar /usr/local/soup/bin/Foo.jar
Hello Foo
Now login as the 'bar' Linux user and notice that it can also run
Foo.jar which is NOT expected
$ whoami
bar
$ id -Z
user_u:user_r:user_t:SystemLow-SystemHigh
$ ls -Z /usr/local/soup/bin/Foo.jar
-rwxr-xr-x. admin admin
system_u:object_r:bin_t:NetworkAdministrator /usr/local/soup/bin/Foo.jar
$ java -jar /usr/local/soup/bin/Foo.jar
Hello Foo
Why is Linux user 'bar' able to run/access Foo.jar when its category
doesn't match Foo.jar's category?
Following is how to create the Foo.jar file:
$ cat Foo.java
public class Foo {
public static void main(String[] args) {
System.out.println("Hello Foo");
}
}
$ cat manifest.txt
Main-Class:
$ javac Foo.java
$ jar cvfe Foo.jar Foo Foo.class
added manifest
adding: Foo.class(in = 409) (out= 282)(deflated 31%)
Best Regards,
Bill
On 05/24/2017 04:39 PM, Philip Seeley wrote:
Hi Bill,
I think this was my mistake in transcribing. The user_u
line after the "semanage user -m" command should be:
user_u user SystemLow
SystemLow-SystemHigh user_r
So the command should have been:
semanage user -m -r s0-s0:c0.c1023 user_u
Or even:
semanage user -m -r SystemLow-SystemHigh user_u
Appologies for that.
Phil
Inactive hide details for Bill D ---25/05/2017
02:28:19---Hello Phil, I have tried your suggestion of
extending the user_u defiBill D ---25/05/2017
02:28:19---Hello Phil, I have tried your suggestion of
extending the user_u definition without
From: Bill D <littus(a)icloud.com>
To: Philip Seeley <pseeley(a)au1.ibm.com>
Cc: littus(a)icloud.com, selinux(a)lists.fedoraproject.org
Date: 25/05/2017 02:28
Subject: Re: Controlling execution of Java JAR files with
SELinux RBAC
Hello Phil,
I have tried your suggestion of extending the user_u
definition without success:
# semanage user -l
Labeling MLS/
MLS/
SELinux User Prefix MCS Level MCS
Range SELinux Roles
git_shell_u user SystemLow
SystemLow git_shell_r
guest_u user SystemLow
SystemLow guest_r
root user SystemLow
SystemLow-SystemHigh staff_r sysadm_r system_r
unconfined_r
staff_u user SystemLow
SystemLow-SystemHigh staff_r sysadm_r system_r
unconfined_r
sysadm_u user SystemLow
SystemLow-SystemHigh sysadm_r
system_u user SystemLow
SystemLow-SystemHigh system_r unconfined_r
unconfined_u user SystemLow
SystemLow-SystemHigh system_r unconfined_r
user_u user SystemLow
SystemLow user_r
xguest_u user SystemLow
SystemLow xguest_r
# semanage user -m -r s0:c0.c1023 user_u
# semanage user -l
Labeling MLS/
MLS/
SELinux User Prefix MCS Level MCS
Range SELinux Roles
git_shell_u user SystemLow
SystemLow git_shell_r
guest_u user SystemLow
SystemLow guest_r
root user SystemLow
SystemLow-SystemHigh staff_r sysadm_r system_r
unconfined_r
staff_u user SystemLow
SystemLow-SystemHigh staff_r sysadm_r system_r
unconfined_r
sysadm_u user SystemLow
SystemLow-SystemHigh sysadm_r
system_u user SystemLow
SystemLow-SystemHigh system_r unconfined_r
unconfined_u user SystemLow
SystemLow-SystemHigh system_r unconfined_r
user_u user SystemLow
SystemHigh user_r
xguest_u user SystemLow
SystemLow xguest_r
# useradd kate
# passwd kate
Changing password for user kate.
New password:
Retype new password:
passwd: all authentication tokens updated successfully.
# semanage login -a kate
libsemanage.validate_handler: MLS range s0 for Unix user
regularuser exceeds allowed range s0:c0.c1023 for SELinux
user user_u (No such file or directory).
libsemanage.validate_handler: seuser mapping [regularuser
-> (user_u, s0)] is invalid (No such file or directory).
libsemanage.dbase_llist_iterate: could not iterate over
records (No such file or directory).
/usr/sbin/semanage: Could not commit semanage transaction
I would greatly appreciate any other hints to make this
work.
Regards,
Bill
On 5/23/2017 8:42 PM, Philip Seeley wrote:
Hi Bill,
This is probably because the
default RHEL6 configuration does
not include any categories in the
user_u SELinux user's range:
# semanage user -l
Labeling MLS/
MLS/
SELinux User Prefix MCS
Level MCS Range
SELinux Roles
guest_u user s0
s0
guest_r
root user s0
s0-s0:c0.c1023
staff_r sysadm_r system_r
unconfined_r
staff_u user s0
s0-s0:c0.c1023
staff_r sysadm_r system_r
unconfined_r
sysadm_u user s0
s0-s0:c0.c1023
sysadm_r
system_u user s0
s0-s0:c0.c1023
system_r unconfined_r
unconfined_u user s0
s0-s0:c0.c1023
system_r unconfined_r
user_u user s0
s0
user_r
You probably have to extend the
user definition to include the
categories you're using. As an
example, this gives all
categories:
# semanage user -m -r s0:c0.c1023
user_u
# semanage user -l
Labeling MLS/
MLS/
SELinux User Prefix MCS
Level MCS Range
SELinux Roles
guest_u user s0
s0
guest_r
root user s0
s0-s0:c0.c1023
staff_r sysadm_r system_r
unconfined_r
staff_u user s0
s0-s0:c0.c1023
staff_r sysadm_r system_r
unconfined_r
sysadm_u user s0
s0-s0:c0.c1023
sysadm_r
system_u user s0
s0-s0:c0.c1023
system_r unconfined_r
unconfined_u user s0
s0-s0:c0.c1023
system_r unconfined_r
user_u user s0
s0:c0.c1023
user_r
Hope that helps.
Phil
Inactive hide details for Bill
Durant
---24/05/2017 12:34:53---Hello
Phil: Thank you for
the suggestion. I have tried the
stepBill Durant ---24/05/2017
12:34:53---Hello Phil: Thank you
for the suggestion. I have tried
the steps from the URL that
From: Bill Durant
<littus(a)icloud.com>
To: Philip Seeley
<pseeley(a)au1.ibm.com>
Cc: littus(a)icloud.com,
selinux(a)lists.fedoraproject.org
Date: 24/05/2017 12:34
Subject: Re: Controlling
execution of Java JAR files with
SELinux RBAC
Hello Phil:
Thank you for the suggestion. I
have tried the steps from the URL
that you provided without
success.
I get an error when I try to
assign Linux user mary to an
SELinux login as follows:
# cat /etc/redhat-release
CentOS release 6.9 (Final)
;;; Add
"s0:c0=NetworkAdministrator" and
"s0:c1=Operator"
to /etc/selinux/targeted/setrans.conf
#
cat /etc/selinux/targeted/setrans.conf
#
# Multi-Category Security
translation table for SELinux
#
# Uncomment the following to
disable translation libary
# disable=1
#
# Objects can be categorized with
0-1023 categories defined by the
admin.
# Objects can be in more than one
category at a time.
# Categories are stored in the
system as c0-c1023. Users can
use this
# table to translate the
categories into a more meaningful
output.
# Examples:
# s0:c0=CompanyConfidential
# s0:c1=PatientRecord
# s0:c2=Unclassified
# s0:c3=TopSecret
#
s0:c1,c3=CompanyConfidentialRedHat
s0:c0=NetworkAdministrator
s0:c1=Operator
s0=SystemLow
s0-s0:c0.c1023=SystemLow-SystemHigh
s0:c0.c1023=SystemHigh
# service mcstrans start
# chcat -L
s0:c0
NetworkAdministrator
s0:c1
Operator
s0
SystemLow
s0-s0:c0.c1023
SystemLow-SystemHigh
s0:c0.c1023
SystemHigh
# useradd mary
# passwd mary
Changing password for user mary.
New password:
Retype new password:
passwd: all authentication tokens
updated successfully.
# semanage login -a mary
# chcat -l --
+NetworkAdministrator mary
libsemanage.validate_handler: MLS
range s0-s0:c0 for Unix user mary
exceeds allowed range s0 for
SELinux user user_u (No such file
or directory).
libsemanage.validate_handler:
seuser mapping [mary -> (user_u,
s0-s0:c0)] is invalid (No such
file or directory).
libsemanage.dbase_llist_iterate:
could not iterate over records
(No such file or directory).
/usr/sbin/semanage: Could not
commit semanage transaction
I would appreciate any hints on
how to resolve that error.
Thanks!
Bill
On 05/23/2017 05:49 PM, Philip
Seeley wrote:
Hi Bill,
Have you thought about using categories?
https://www.centos.org/docs/5/html/Deployment_Guide-en-US/sec-mcs-getstar...
Cheers
Phil
Inactive hide details for Bill
D ---24/05/2017
09:52:00---Greetings: I have been
trying to figure out how to control
the executBill D ---24/05/2017 09:52:00---Greetings: I have
been trying to figure out how to control the execution of
Java
From: Bill D <littus(a)icloud.com>
To: selinux(a)lists.fedoraproject.org
Cc: littus(a)icloud.com
Date: 24/05/2017 09:52
Subject: Controlling execution of Java JAR files with
SELinux RBAC
Greetings:
I have been trying to figure out how to control the
execution of Java
JAR files with SELinux RBAC.
I have two Linux users named joe and mary and two Java JAR
files named
jack.jar and mary.jar.
Here is how jack executes jack.jar: java -jar jack.jar
Here is how mary executes mary.jar: java -jar mary.jar
I would like SELinux RBAC to prevent jack from executing
mary.jar and
prevent mary from executing jack.jar.
How to configure SELinux RBAC to make that happen?
I have tried various approaches without success. I have
also tried the
steps in
http://forums.fedoraforum.org/archive/index.php/t-222938.html
without success.
I would greatly appreciate any hints.
Regards,
Bill
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