Bug 1896457

Summary: varnish unable to start because selinux is preventing lto1-wpa from map access on tempfiles
Product: [Fedora] Fedora Reporter: Ingvar Hagelund <ingvar>
Component: selinux-policyAssignee: Zdenek Pytela <zpytela>
Status: CLOSED ERRATA QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: medium Docs Contact:
Priority: medium    
Version: 33CC: dwalsh, emilkm, grepl.miroslav, lvrabec, mmalik, plautrba, vmojzis, zpytela
Target Milestone: ---Keywords: Triaged
Target Release: ---   
Hardware: Unspecified   
OS: Linux   
Whiteboard:
Fixed In Version: selinux-policy-3.14.6-31.fc33 Doc Type: If docs needed, set a value
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Clone Of: Environment:
Last Closed: 2020-12-12 01:04:56 UTC Type: Bug
Regression: --- Mount Type: ---
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description Ingvar Hagelund 2020-11-10 15:47:42 UTC
Description of problem:
On a freshly installed f33, service varnish won't start as selinux is preventing lto1-wpa from map access on tempfiles. See bz #1892552 for more details.

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


How reproducible:
selinux-policy-3.14.6-29.fc33.noarch

Steps to Reproduce:
1. Install Fedora 33
2. dnf update; dnf install gcc make varnish; journalctl -u varnish -f
3. systemctl start varnish

Actual results:
SELinux is preventing lto1-wpa from map access on the file /tmp/ccTOlFtj.o.

Expected results:
Varnish starting up as usual. This is a regression from f32.

Additional info:
Bluntly doing setenforce 0, makes varnish start.

FAQ: Why do a daemon want to run gcc? One of the features of varnish that gives its amazing speed, is using gcc behind the scenes to compile its VCL configuration to a dynamic library, and then linking it runtime. 

Nov 10 16:45:36 f33 varnishd[21887]: Error:
Nov 10 16:45:36 f33 varnishd[21887]: Message from C-compiler:
Nov 10 16:45:36 f33 varnishd[21887]: lto1: fatal error: Cannot map /tmp/ccs8p4rl.o
Nov 10 16:45:36 f33 varnishd[21887]: compilation terminated.
Nov 10 16:45:36 f33 varnishd[21887]: lto-wrapper: fatal error: gcc returned 1 exit status
Nov 10 16:45:36 f33 varnishd[21887]: compilation terminated.
Nov 10 16:45:36 f33 varnishd[21887]: /usr/bin/ld: error: lto-wrapper failed
Nov 10 16:45:36 f33 varnishd[21887]: collect2: error: ld returned 1 exit status
Nov 10 16:45:36 f33 varnishd[21887]: Running C-compiler failed, exited with 1
Nov 10 16:45:36 f33 varnishd[21887]: VCL compilation failed

Comment 1 Zdenek Pytela 2020-11-10 15:55:04 UTC
Hi,

Is this the only denial you see now?

type=AVC msg=audit(1604000868.64:265): avc:  denied  { map } for  pid=23973 comm="lto1-wpa" path="/tmp/ccUUg65n.o" dev="tmpfs" ino=56637 scontext=system_u:system_r:varnishd_t:s0 tcontext=system_u:object_r:varnishd_tmp_t:s0 tclass=file permissive=0

Comment 2 Ingvar Hagelund 2020-11-12 10:14:00 UTC
Yes, that is the only one I get.

Comment 3 Zdenek Pytela 2020-11-12 10:20:21 UTC
I've submitted a Fedora PR to address the issue:
https://bugzilla.redhat.com/show_bug.cgi?id=1890884#c7

Comment 4 Ingvar Hagelund 2020-11-12 14:41:14 UTC
The default domain_can_mmap_files off was added for security reasons:

  # dnf install selinux-policy-devel
  # semanage boolean -l | grep domain_can_mmap_files
  domain_can_mmap_files          (on   ,  off)  Allow any process to mmap any file on system with attribute file_type.

A quick and dirty workaround is to switch if on again:

  # setsebool domain_can_mmap_files on

Se for example here for some notes on the security impact:

https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/7.6_release_notes/new_features_security

Comment 5 Zdenek Pytela 2020-11-12 15:10:03 UTC
The issue will be resolved allowing just one map permission, see the PR - this is the correct link:
https://github.com/fedora-selinux/selinux-policy-contrib/pull/363

Comment 6 Zdenek Pytela 2020-11-23 14:18:15 UTC
commit 2b2a20eb1be3213fd8d3b3e2f474e8e8790ce7ce (HEAD -> f33, upstream/f33)
Author: Zdenek Pytela <zpytela>
Date:   Thu Nov 12 11:19:01 2020 +0100

    Allow varnish map its private tmp files
    
    Resolves: rhbz#1896457

Comment 7 Fedora Update System 2020-12-09 14:37:10 UTC
FEDORA-2020-aff0be81b3 has been submitted as an update to Fedora 33. https://bodhi.fedoraproject.org/updates/FEDORA-2020-aff0be81b3

Comment 8 Fedora Update System 2020-12-11 00:04:20 UTC
FEDORA-2020-aff0be81b3 has been pushed to the Fedora 33 testing repository.
Soon you'll be able to install the update with the following command:
`sudo dnf upgrade --enablerepo=updates-testing --advisory=FEDORA-2020-aff0be81b3`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2020-aff0be81b3

See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.

Comment 9 Fedora Update System 2020-12-12 01:04:56 UTC
FEDORA-2020-aff0be81b3 has been pushed to the Fedora 33 stable repository.
If problem still persists, please make note of it in this bug report.

Comment 10 Ingvar Hagelund 2021-11-09 08:57:26 UTC
*** Bug 1892552 has been marked as a duplicate of this bug. ***