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Bug 1901984 - new tcsd selinux denial with trousers-0.3.15-1.el8
Summary: new tcsd selinux denial with trousers-0.3.15-1.el8
Keywords:
Status: CLOSED DUPLICATE of bug 1898694
Alias: None
Product: Red Hat Enterprise Linux 8
Classification: Red Hat
Component: selinux-policy
Version: 8.4
Hardware: All
OS: Linux
medium
medium
Target Milestone: rc
: 8.0
Assignee: Zdenek Pytela
QA Contact: Milos Malik
URL:
Whiteboard:
Depends On:
Blocks: 1882414
TreeView+ depends on / blocked
 
Reported: 2020-11-26 14:37 UTC by Karel Srot
Modified: 2020-12-08 06:56 UTC (History)
5 users (show)

Fixed In Version:
Doc Type: If docs needed, set a value
Doc Text:
Clone Of:
Environment:
Last Closed: 2020-11-30 20:14:03 UTC
Type: Bug
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)

Description Karel Srot 2020-11-26 14:37:01 UTC 
Description of problem:

With new trousers-0.3.15-1.el8, during the tcsd start the following denial appears:

selinux-policy-3.14.3-56.el8.noarch
----
time->Thu Nov 26 13:00:04 2020
type=PROCTITLE msg=audit(1606395604.084:1317): proctitle="/sbin/tcsd"
type=SYSCALL msg=audit(1606395604.084:1317): arch=c000003e syscall=106 success=no exit=-1 a0=3b a1=0 a2=7ffd4f01fb60 a3=f0000000 items=0 ppid=1 pid=25550 auid=4294967295 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=(none) ses=4294967295 comm="tcsd" exe="/usr/sbin/tcsd" subj=system_u:system_r:tcsd_t:s0 key=(null)
type=AVC msg=audit(1606395604.084:1317): avc:  denied  { setgid } for  pid=25550 comm="tcsd" capability=6  scontext=system_u:system_r:tcsd_t:s0 tcontext=system_u:system_r:tcsd_t:s0 tclass=capability permissive=0

This is due to a new setgid call as can be seen in sources
https://sourceforge.net/p/trousers/trousers/ci/master/tree/src/tcsd/svrside.c#l475

There are no other denial even in permissive mode, at least in my test case.

Please address this bug in 8.4.

Version-Release number of selected component (if applicable):
selinux-policy-3.14.3-56.el8.noarch

How reproducible:
always.
Run 
'systemctl start tcsd' on a system with TPM device

Actual results:
AVC present

Expected results:
No AVC present
Comment 1 Zdenek Pytela 2020-11-26 16:40:37 UTC 
This bug will be evaluated for inclusion into one of the next minor product updates. If you want to expedite delivering the fix, please include business justification.
Comment 3 Karel Srot 2020-11-26 16:48:04 UTC 
Since I am not really tcsd user, I am forwarding the needinfo to the developer. Jerry, are you able to provide additional justification or do you think we can postpone a fix to a future release?
Comment 5 Jerry Snitselaar 2020-11-26 22:30:12 UTC 
I have another bug open bz 1898694 to selinux-policy to add a setgid capability for tcsd. I noticed the issue when looking at a fix for a coverity scan issue.
Comment 6 Jerry Snitselaar 2020-11-26 22:31:04 UTC 
My plan was for the trousers update to go into 8.4
Comment 7 Milos Malik 2020-11-27 07:53:31 UTC 
To have a complete picture, here is the only SELinux denial which appears in permissive mode is:
----
type=PROCTITLE msg=audit(11/27/2020 02:50:32.321:358) : proctitle=/sbin/tcsd 
type=SYSCALL msg=audit(11/27/2020 02:50:32.321:358) : arch=x86_64 syscall=setgid success=yes exit=0 a0=tss a1=0x0 a2=0x7fffe9ec08c0 a3=0xf0000000 items=0 ppid=1 pid=12358 auid=unset uid=root gid=tss euid=root suid=root fsuid=root egid=tss sgid=tss fsgid=tss tty=(none) ses=unset comm=tcsd exe=/usr/sbin/tcsd subj=system_u:system_r:tcsd_t:s0 key=(null) 
type=AVC msg=audit(11/27/2020 02:50:32.321:358) : avc:  denied  { setgid } for  pid=12358 comm=tcsd capability=setgid  scontext=system_u:system_r:tcsd_t:s0 tcontext=system_u:system_r:tcsd_t:s0 tclass=capability permissive=1 
----
Comment 8 Milos Malik 2020-11-27 09:04:04 UTC 
I believe this bug is a duplicate of BZ#1898694.
Comment 10 Zdenek Pytela 2020-11-30 20:14:03 UTC 

*** This bug has been marked as a duplicate of bug 1898694 ***
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