Bug 1830493

Summary:	Typo in section 4.5.
Product:	Red Hat Enterprise Linux 7	Reporter:	Tsur Trieger <triger_t>
Component:	doc-SELinux_Users_and_Administrators_Guide	Assignee:	Mirek Jahoda <mjahoda>
Status:	CLOSED CURRENTRELEASE	QA Contact:	Milos Malik <mmalik>
Severity:	low	Docs Contact:
Priority:	high
Version:	7.8	CC:	mprpic, pkennedy, plautrba, rhel-docs, zach
Target Milestone:	rc	Keywords:	Documentation, EasyFix
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Hardware:	Unspecified
OS:	Linux
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Fixed In Version:		Doc Type:	If docs needed, set a value
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Clone Of:		Environment:
Last Closed:	2020-05-29 09:52:48 UTC	Type:	Bug
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Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
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Description Tsur Trieger 2020-05-02 08:22:17 UTC

Description of problem:
I think there is a mistake on page 32, section 4.5. Changing SELinux modes at boot time


Version-Release number of selected component (if applicable):


How reproducible:


Steps to Reproduce:
On page 32, under 4.5. Changing SELinux modes at boot time

..."In permissive mode, only the first denial is reported. However, in enforcing mode you might get a
denial on reading a directory and an application stops. In permissive mode, you get the same AVC
message, but the application continues reading files in the directory and you get an AVC for each
denial in addition."




Actual results:
As far as I know, Permissive mode let the application continue to run, but report EACH violation it made. Therefore, on permissive mode, ALL denials are reported and not only the first one, due to the fact that the application will continue to run despite the violations.


Expected results:


Additional info:
As far as I know, the correct sentence is: ..."In permissive mode, all denials are reported. However,"...

Link to the manual:
https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/pdf/selinux_users_and_administrators_guide/Red_Hat_Enterprise_Linux-7-SELinux_Users_and_Administrators_Guide-en-US.pdf

Comment 1 Petr Bokoc 2020-05-11 11:51:30 UTC

Hello, thank you for the report. It seems that this has been misfiled, the document is RHEL 7 documentation, not Fedora documentation, so I'm changing the product and component and someone from the RHEL documentation team will pick this up.

Comment 3 Mirek Jahoda 2020-05-18 16:18:15 UTC

I believe that it should read as:

"In *enforcing* mode, only the first denial is reported. However, in enforcing mode you might get a
denial on reading a directory and an application stops. In permissive mode, you get the same AVC
message, but the application continues reading files in the directory and you get an AVC for each
denial in addition."

Petr, what is the most appropriate wording from your perspective?

Comment 4 Petr Lautrbach 2020-05-18 16:41:50 UTC

Let me show you an example:

[root@localhost ~]# setenforce 1
[root@localhost ~]# date
Mon May 18 18:35:33 CEST 2020
[root@localhost ~]# runcon -t user_t -r user_r -u user_u -l s0 -- cat /etc/passwd > /dev/null
runcon: 'cat': Permission denied
[root@localhost ~]# runcon -t user_t -r user_r -u user_u -l s0 -- cat /etc/passwd > /dev/null
runcon: 'cat': Permission denied
[root@localhost ~]# runcon -t user_t -r user_r -u user_u -l s0 -- cat /etc/passwd > /dev/null
runcon: 'cat': Permission denied
[root@localhost ~]# ausearch -m avc -ts 18:35:33
----
time->Mon May 18 18:35:38 2020
type=AVC msg=audit(1589819738.988:690): avc:  denied  { transition } for  pid=22368 comm="runcon" path="/usr/bin/cat" dev="dm-1" ino=786826 scontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tcontext=user_u:user_r:user_t:s0 tclass=process permissive=0
----
time->Mon May 18 18:35:38 2020
type=AVC msg=audit(1589819738.988:691): avc:  denied  { transition } for  pid=22368 comm="runcon" path="/usr/bin/cat" dev="dm-1" ino=786826 scontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tcontext=user_u:user_r:user_t:s0 tclass=process permissive=0
----
time->Mon May 18 18:35:39 2020
type=AVC msg=audit(1589819739.842:692): avc:  denied  { transition } for  pid=22374 comm="runcon" path="/usr/bin/cat" dev="dm-1" ino=786826 scontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tcontext=user_u:user_r:user_t:s0 tclass=process permissive=0
----
time->Mon May 18 18:35:39 2020
type=AVC msg=audit(1589819739.842:693): avc:  denied  { transition } for  pid=22374 comm="runcon" path="/usr/bin/cat" dev="dm-1" ino=786826 scontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tcontext=user_u:user_r:user_t:s0 tclass=process permissive=0
----
time->Mon May 18 18:35:40 2020
type=AVC msg=audit(1589819740.673:694): avc:  denied  { transition } for  pid=22375 comm="runcon" path="/usr/bin/cat" dev="dm-1" ino=786826 scontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tcontext=user_u:user_r:user_t:s0 tclass=process permissive=0
----
time->Mon May 18 18:35:40 2020
type=AVC msg=audit(1589819740.673:695): avc:  denied  { transition } for  pid=22375 comm="runcon" path="/usr/bin/cat" dev="dm-1" ino=786826 scontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tcontext=user_u:user_r:user_t:s0 tclass=process permissive=0


You get the same AVC denial message several times. But:

[root@localhost ~]# runcon -t user_t -r user_r -u user_u -l s0 -- cat /etc/passwd > /dev/null
[root@localhost ~]# runcon -t user_t -r user_r -u user_u -l s0 -- cat /etc/passwd > /dev/null
[root@localhost ~]# runcon -t user_t -r user_r -u user_u -l s0 -- cat /etc/passwd > /dev/null
[root@localhost ~]# ausearch -m avc -ts 18:38:24
----
time->Mon May 18 18:38:27 2020
type=AVC msg=audit(1589819907.682:710): avc:  denied  { transition } for  pid=22827 comm="runcon" path="/usr/bin/cat" dev="dm-1" ino=786826 scontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tcontext=user_u:user_r:user_t:s0 tclass=process permissive=1

You get only 1 AVC denial message despite the fact that SELinux would denied transition at least 3 times in enforcing.

Comment 6 Mirek Jahoda 2020-05-29 09:52:48 UTC

Based on the comment 4, I made the description of permissive mode clearer:
https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/selinux_users_and_administrators_guide/sect-security-enhanced_linux-enabling_and_disabling_selinux-dracut-parameters

Thank you for the report.