Bug 1697886

Summary: Denials of rngd running execmem while loading shared libraries during startup in F30
Product: [Fedora] Fedora Reporter: Matt Fagnani <matt.fagnani>
Component: selinux-policyAssignee: Zdenek Pytela <zpytela>
Status: CLOSED ERRATA QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: low Docs Contact:
Priority: low    
Version: 30CC: dwalsh, lvrabec, plautrba, zpytela
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Hardware: Unspecified   
OS: Unspecified   
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Fixed In Version: selinux-policy-3.14.3-55.fc30 Doc Type: If docs needed, set a value
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Last Closed: 2020-01-31 01:12:18 UTC Type: Bug
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description Matt Fagnani 2019-04-09 08:54:39 UTC
Description of problem:

I've seen denials of rngd running execmem several times when booting in F30. The denials started right after I ran dnf system-upgrade from F29. The audit messages are of the form.

type=AVC msg=audit(1554728843.716:120): avc:  denied  { execmem } for  pid=879 comm="rngd" scontext=system_u:system_r:rngd_t:s0 tcontext=system_u:system_r:rngd_t:s0 tclass=process permissive=0

The journal showed that rngd had an error loading shared libraries and stopped unexpectedly due to the denials.

audit[1]: SERVICE_START pid=1 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:init_t:s0 msg='unit=rngd comm="systemd" exe="/usr/lib/systemd/systemd" hostname=? addr=? terminal=? res=success'
audit[879]: AVC avc:  denied  { execmem } for  pid=879 comm="rngd" scontext=system_u:system_r:rngd_t:s0 tcontext=system_u:system_r:rngd_t:s0 tclass=process permissive=0
rngd[879]: /sbin/rngd: error while loading shared libraries: cannot make segment writable for relocation: Permission denied
audit[1]: SERVICE_STOP pid=1 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:init_t:s0 msg='unit=rngd comm="systemd" exe="/usr/lib/systemd/systemd" hostname=? addr=? terminal=? res=failed'
systemd[1]: rngd.service: Main process exited, code=exited, status=127/n/a
systemd[1]: rngd.service: Failed with result 'exit-code'.

rngd doesn't appear to restart itself. I'm running the targeted policy 3.14.3-27 in enforcing mode.

Version-Release number of selected component (if applicable):
rng-tools-0:6.7-1.fc30.i686
selinux-policy-0:3.14.3-27.fc30.noarch

How reproducible:
The denials happened 7 times which is most if not all of the times I've booted in F30.

Steps to Reproduce:
1. Boot in F30 with the rngd service enabled
2. sudo ausearch -m AVC,USER_AVC,SELINUX_ERR -ts today
3. journalctl --since today -g rngd
4. systemctl status rngd

Actual results:
rngd was denied the action execmem while loading shared libraries and exited several times during startup in F30.

Expected results:
No denials occur and rngd starts normally.

Additional info:

Comment 1 Lukas Vrabec 2020-01-10 13:45:49 UTC
commit 3b51277ea03d4df62f01f8082c8e5d0ee34a9379 (HEAD -> rawhide, origin/rawhide, origin/HEAD)
Author: Nikola Knazekova <nknazeko>
Date:   Fri Jan 10 13:49:52 2020 +0100

    Boolean: rngd_t to use executable memory
    
    New boolean for rngd_t,daemon that feeds random data from hardware device to kernel, to execute memory.
    
    Fixed bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1697886

Comment 2 Fedora Update System 2020-01-14 02:48:23 UTC
selinux-policy-3.14.3-55.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-2020-384545235e

Comment 3 Fedora Admin XMLRPC Client 2020-01-23 16:24:55 UTC
This package has changed maintainer in the Fedora.
Reassigning to the new maintainer of this component.

Comment 4 Fedora Update System 2020-01-31 01:12:18 UTC
selinux-policy-3.14.3-55.fc30 has been pushed to the Fedora 30 stable repository. If problems still persist, please make note of it in this bug report.