Bug 1310336 - EPSON printer drivers usb backend SELinux denial
EPSON printer drivers usb backend SELinux denial
Product: Fedora
Classification: Fedora
Component: selinux-policy (Show other bugs)
Unspecified Unspecified
high Severity high
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Assigned To: Lukas Vrabec
Fedora Extras Quality Assurance
: Reopened
Depends On:
  Show dependency treegraph
Reported: 2016-02-20 09:41 EST by Aleksandar Kostadinov
Modified: 2016-12-20 13:53 EST (History)
5 users (show)

See Also:
Fixed In Version: selinux-policy-3.13.1-158.12.fc23
Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of:
Last Closed: 2016-12-20 13:53:30 EST
Type: Bug
Regression: ---
Mount Type: ---
Documentation: ---
Verified Versions:
Category: ---
oVirt Team: ---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---

Attachments (Terms of Use)
new denial report (1.78 KB, text/plain)
2016-05-02 12:13 EDT, Aleksandar Kostadinov
no flags Details

  None (edit)
Description Aleksandar Kostadinov 2016-02-20 09:41:59 EST
Pasting setroubleshooter output below. In short, after installing v1.6.4 "wp-4525" [1] driver and restarting cups, there is a file created /var/run/ecblp0. The epson backend it seems uses that to operate the printer.

I thought we can change policy so that the file can be opened in cups context.

Or should that be fixed somehow in the driver RPM? I doubt EPSON will fix it though as their RPM build is targeting all sorts of distros and requires `lsb` package. 

To workaround the issue I did manually in console:

> chcon system_u:object_r:cupsd_var_run_t:s0 /var/run/ecblp0

[1] http://download.ebz.epson.net/dsc/search/01/search/searchModule (search for "wp-4525")

=================== PASTED DENIAL ===========================================

SELinux is preventing /usr/lib/cups/backend/ecblp from 'open' accesses on the fifo_file /run/ecblp0.

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

If you believe that ecblp should be allowed open access on the ecblp0 fifo_file by default.
Then you should report this as a bug.
You can generate a local policy module to allow this access.
allow this access for now by executing:
# grep ecblp /var/log/audit/audit.log | audit2allow -M mypol
# semodule -i mypol.pp

Additional Information:
Source Context                system_u:system_r:cupsd_t:s0-s0:c0.c1023
Target Context                unconfined_u:object_r:var_run_t:s0
Target Objects                /run/ecblp0 [ fifo_file ]
Source                        ecblp
Source Path                   /usr/lib/cups/backend/ecblp
Port                          <Unknown>
Host                          (removed)
Source RPM Packages           epson-printer-utility-1.0.0-1lsb3.2.x86_64
Target RPM Packages           
Policy RPM                    selinux-policy-3.13.1-158.6.fc23.noarch
Selinux Enabled               True
Policy Type                   targeted
Enforcing Mode                Enforcing
Host Name                     (removed)
Platform                      Linux (removed) 4.3.5-300.fc23.x86_64 #1 SMP Mon
                              Feb 1 03:18:41 UTC 2016 x86_64 x86_64
Alert Count                   1
First Seen                    2016-02-20 15:53:23 EET
Last Seen                     2016-02-20 15:53:23 EET
Local ID                      862c222e-0122-4e5e-b09f-b612f92837c2

Raw Audit Messages
type=AVC msg=audit(1455976403.965:1640): avc:  denied  { open } for  pid=27960 comm="ecblp" path="/run/ecblp0" dev="tmpfs" ino=207126 scontext=system_u:system_r:cupsd_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:var_run_t:s0 tclass=fifo_file permissive=0

type=SYSCALL msg=audit(1455976403.965:1640): arch=x86_64 syscall=open success=no exit=EACCES a0=7ffe49ad63f0 a1=81 a2=0 a3=120 items=0 ppid=26032 pid=27960 auid=4294967295 uid=4 gid=7 euid=4 suid=4 fsuid=4 egid=7 sgid=7 fsgid=7 tty=(none) ses=4294967295 comm=ecblp exe=/usr/lib/cups/backend/ecblp subj=system_u:system_r:cupsd_t:s0-s0:c0.c1023 key=(null)

Hash: ecblp,cupsd_t,var_run_t,fifo_file,open
Comment 1 Lukas Vrabec 2016-03-16 17:29:10 EDT
commit 6f85286ad59733ea7e65d54f5eaf563960ae6f10
Author: Lukas Vrabec <lvrabec@redhat.com>
Date:   Wed Mar 16 22:00:02 2016 +0100

    Label /var/run/ecblp0 as cupsd_var_run_t due to this fifo_file is used by epson drivers. rhbz#1310336
Comment 2 Aleksandar Kostadinov 2016-03-17 03:43:31 EDT
I don't know your rule and I'm not sure epson drivers have support for multiple printers [1], but it appears to me that we want any /var/run/ecblp# labeled as `cupsd_var_run_t`. 

[1] don't have multiple printers to test with
Comment 3 Fedora Update System 2016-03-30 10:40:54 EDT
selinux-policy-3.13.1-158.12.fc23 has been submitted as an update to Fedora 23. https://bodhi.fedoraproject.org/updates/FEDORA-2016-1cdba6b1c7
Comment 4 Fedora Update System 2016-03-30 18:54:33 EDT
selinux-policy-3.13.1-158.12.fc23 has been pushed to the Fedora 23 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-2016-1cdba6b1c7
Comment 5 Fedora Update System 2016-04-05 09:52:00 EDT
selinux-policy-3.13.1-158.12.fc23 has been pushed to the Fedora 23 stable repository. If problems still persist, please make note of it in this bug report.
Comment 6 Fedora Update System 2016-04-05 12:19:41 EDT
selinux-policy-3.13.1-158.12.fc23 has been pushed to the Fedora 23 stable repository. If problems still persist, please make note of it in this bug report.
Comment 7 Aleksandar Kostadinov 2016-05-02 12:13 EDT
Created attachment 1153001 [details]
new denial report

I just had a chance to try that again. I still get the newly attached denial. I have `selinux-policy-3.13.1-158.14.fc23.noarch`. This is after reboot of the OS.

I'm not sure why it is not working. Please note that the fifo is created by a systemctl service. It does not exist before `systemctl start ecbd`. Only then "/run/ecblp0" is created. Let me know if you need any other info.
Comment 8 Fedora End Of Life 2016-11-24 10:40:03 EST
This message is a reminder that Fedora 23 is nearing its end of life.
Approximately 4 (four) weeks from now Fedora will stop maintaining
and issuing updates for Fedora 23. It is Fedora's policy to close all
bug reports from releases that are no longer maintained. At that time
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Comment 9 Fedora End Of Life 2016-12-20 13:53:30 EST
Fedora 23 changed to end-of-life (EOL) status on 2016-12-20. Fedora 23 is
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