Bug 1711122 - SELinux is preventing /usr/lib/systemd/systemd-journald from 'kill' accesses on the cap_userns labeled syslogd_t.
Summary: SELinux is preventing /usr/lib/systemd/systemd-journald from 'kill' accesses ...
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Fedora
Classification: Fedora
Component: selinux-policy
Version: 30
Hardware: x86_64
OS: Unspecified
low
low
Target Milestone: ---
Assignee: Lukas Vrabec
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard: abrt_hash:9069a889e059c4215a47d996d20...
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2019-05-17 02:06 UTC by Tad
Modified: 2019-05-21 01:09 UTC (History)
5 users (show)

Fixed In Version: selinux-policy-3.14.3-37.fc30
Doc Type: If docs needed, set a value
Doc Text:
Clone Of:
Environment:
Last Closed: 2019-05-21 01:09:33 UTC
Type: ---
Embargoed:


Attachments (Terms of Use)

Description Tad 2019-05-17 02:06:41 UTC
Description of problem:
SELinux is preventing /usr/lib/systemd/systemd-journald from 'kill' accesses on the cap_userns labeled syslogd_t.

*****  Plugin catchall (100. confidence) suggests   **************************

If you believe that systemd-journald should be allowed kill access on cap_userns labeled syslogd_t by default.
Then you should report this as a bug.
You can generate a local policy module to allow this access.
Do
allow this access for now by executing:
# ausearch -c 'systemd-journal' --raw | audit2allow -M my-systemdjournal
# semodule -X 300 -i my-systemdjournal.pp

Additional Information:
Source Context                system_u:system_r:syslogd_t:s0
Target Context                system_u:system_r:syslogd_t:s0
Target Objects                Unknown [ cap_userns ]
Source                        systemd-journal
Source Path                   /usr/lib/systemd/systemd-journald
Port                          <Unknown>
Host                          (removed)
Source RPM Packages           systemd-241-8.git9ef65cb.fc30.x86_64
Target RPM Packages           
Policy RPM                    selinux-policy-3.14.3-35.fc30.noarch
Selinux Enabled               True
Policy Type                   targeted
Enforcing Mode                Enforcing
Host Name                     (removed)
Platform                      Linux (removed) 5.0.16-300.fc30.x86_64 #1 SMP Tue
                              May 14 19:33:09 UTC 2019 x86_64 x86_64
Alert Count                   5325
First Seen                    2019-04-24 20:55:14 EDT
Last Seen                     2019-05-16 22:05:21 EDT
Local ID                      ad5f9279-048b-489e-a46f-af580090907b

Raw Audit Messages
type=AVC msg=audit(1558058721.42:530): avc:  denied  { kill } for  pid=991 comm="systemd-journal" capability=5  scontext=system_u:system_r:syslogd_t:s0 tcontext=system_u:system_r:syslogd_t:s0 tclass=cap_userns permissive=0


type=SYSCALL msg=audit(1558058721.42:530): arch=x86_64 syscall=kill success=no exit=EPERM a0=10bc a1=0 a2=ffffffff a3=12c3a2 items=0 ppid=1 pid=991 auid=4294967295 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=(none) ses=4294967295 comm=systemd-journal exe=/usr/lib/systemd/systemd-journald subj=system_u:system_r:syslogd_t:s0 key=(null)

Hash: systemd-journal,syslogd_t,syslogd_t,cap_userns,kill

Version-Release number of selected component:
selinux-policy-3.14.3-35.fc30.noarch

Additional info:
component:      selinux-policy
reporter:       libreport-2.10.0
hashmarkername: setroubleshoot
kernel:         5.0.16-300.fc30.x86_64
type:           libreport

Comment 1 Tad 2019-05-17 03:25:14 UTC
This seems to be caused by firejail, and occurs on every sandbox start.
I've reported it there: https://github.com/netblue30/firejail/issues/2702
But I'm not sure *why* it happens, I know it didn't happen with F29.
It doesn't seem to be a regression on firejail's side either.

Comment 2 Lukas Vrabec 2019-05-17 20:13:52 UTC
Tad,

You only see this SELinux denial or some functionality is broken with syslogd? 

Thanks,
Lukas.

Comment 3 Tad 2019-05-17 21:31:22 UTC
I have not seen any broken functionality.
There are no relevant errors in the logs.
I haven't changed any defaults for journald or syslogd.

I thought I narrowed it down to firejail (built from master), but it
seems to also happen when Evolution or Liferea use/start webkit2gtk3.
To be clear running Liferea loading an RSS feed that 404's without using
firejail will cause the denial.

From what I can tell this happens anytime something uses namespaces.
So firejail, webkit2gtk, qtwebengine, etc.

It must be a regression in either systemd from 239 to 241 or a change
in Fedora's selinux-policy.

I can reproduce it on multiple systems.
5000+ denials on one machine, 3000+ on another, and 300+ on some others.

It happens every few seconds to every few minutes.

Comment 4 Lukas Vrabec 2019-05-17 21:41:36 UTC
THanks, it looks like good candidate to dontaudit. 

commit d429ac797ecae49117cd8be4564dd73793d2baf3 (HEAD -> rawhide)
Author: Lukas Vrabec <lvrabec>
Date:   Fri May 17 23:41:17 2019 +0200

    Dontaudit syslogd_t using kill in unamespaces BZ(1711122)

Comment 5 Fedora Update System 2019-05-18 11:03:29 UTC
selinux-policy-3.14.3-37.fc30 has been submitted as an update to Fedora 30. https://bodhi.fedoraproject.org/updates/FEDORA-2019-40c077f70d

Comment 6 Fedora Update System 2019-05-19 00:51:01 UTC
selinux-policy-3.14.3-37.fc30 has been pushed to the Fedora 30 testing repository. If problems still persist, please make note of it in this bug report.
See https://fedoraproject.org/wiki/QA:Updates_Testing for
instructions on how to install test updates.
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2019-40c077f70d

Comment 7 Fedora Update System 2019-05-21 01:09:33 UTC
selinux-policy-3.14.3-37.fc30 has been pushed to the Fedora 30 stable repository. If problems still persist, please make note of it in this bug report.


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