7:22 p.m.
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
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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