Fedora with SELinux and Docker volumes permissions

[lnguyen4]

I am having a hard time figuring out how to add third-party extension to a docker instance.
I am using Fedora Workstation 42.

So, I have the following docker-compose.yml file as follow:

volumes:
  data:
  extensions:
services:
  freshrss:
    image: freshrss/freshrss:latest
    # # Optional build section if you want to build the image locally:
    # build:
    #   # Pick #latest (slow releases) or #edge (rolling release) or a specific release like #1.21.0
    #   context: https://github.com/FreshRSS/FreshRSS.git#latest
    #   dockerfile: Docker/Dockerfile-Alpine
    container_name: freshrss
    hostname: freshrss
    restart: unless-stopped
    logging:
      options:
        max-size: 10m
    volumes:
      - data:/var/www/FreshRSS/data
      - ./extensions:/var/www/FreshRSS/extensions
    ports:
      - 8080:80
    environment:
      TZ: America/New_York
      CRON_MIN: '3,33'
      TRUSTED_PROXY: 172.16.0.1/12 192.168.0.1/16

Then i created /home/dir/.config/freshrss/extensions/ directory. I cd to /home/dir/.config/freshrss and invoke docker-compose up -d.

I finished the initial completion at localhost:8080 on firefox, where all checks were marked green and finished with no error.

Then, I downloaded the Extensions-master.zip and extracted them. I copied the xExtension-Youtube dir to /home/dir/.config/freshrss/extensions/ . I invoke docker restart freshrss, but on firefox, I don't see the button at all to use the extension when I go to the extensions setting.

What problem am i having? Is it to do with permission rights or something on the dir?

Here, I include some info from the docker inspect freshrss command

...
"HostConfig": {
            "Binds": [
                "/home/dir/.config/freshrss/extensions:/var/www/FreshRSS/extensions:rw"
            ],

...
"Mounts": [
            {
                "Type": "bind",
                "Source": "/home/dir/.config/freshrss/extensions",
                "Destination": "/var/www/FreshRSS/extensions",
                "Mode": "rw",
                "RW": true,
                "Propagation": "rprivate"
            },
            {
                "Type": "volume",
                "Name": "freshrss_data",
                "Source": "/var/lib/docker/volumes/freshrss_data/_data",
                "Destination": "/var/www/FreshRSS/data",
                "Driver": "local",
                "Mode": "z",
                "RW": true,
                "Propagation": ""
            }

Appreciate any help here.

[Inverle]

I don't see the button at all to use the extension when I go to the extensions setting

Make sure you aren't seeing a cached version of the extensions page, by adding &123 to the end of the URL e.g. http://localhost:8080/i/?c=extension&123

[lnguyen4]

I don't see the button at all to use the extension when I go to the extensions setting

Make sure you aren't seeing a cached version of the extensions page, by adding &123 to the end of the URL e.g. http://localhost:8080/i/?c=extension&123

Thanks, I tried with the &123 appended to the end of url. Still, extension is not available

[Inverle]

What is the output of:
tree -paugh /home/dir/.config/freshrss/extensions
and
docker logs freshrss 2>&1 | egrep '^(FreshRSS|\[|PHP)'

[lnguyen4]

What is the output of: tree -paugh /home/dir/.config/freshrss/extensions and docker logs freshrss 2>&1 | egrep '^(FreshRSS|\[|PHP)'

the tree command gives me:

[drwxr-xr-x user  user     36]  /home/user/.config/freshrss/extensions
└── [drwxrwxr-x user  user    122]  xExtension-YouTube
    ├── [-rw-rw-r-- user  user   1.8K]  configure.phtml
    ├── [-rw-rw-r-- user  user   7.9K]  extension.php
    ├── [drwxrwxr-x user  user     16]  i18n
    │   ├── [drwxrwxr-x user  user     14]  de
    │   │   └── [-rw-rw-r-- user  user    320]  ext.php
    │   ├── [drwxrwxr-x user  user     14]  en
    │   │   └── [-rw-rw-r-- user  user    298]  ext.php
    │   ├── [drwxrwxr-x user  user     14]  fr
    │   │   └── [-rw-rw-r-- user  user    352]  ext.php
    │   └── [drwxrwxr-x user  user     14]  tr
    │       └── [-rw-rw-r-- user  user    344]  ext.php
    ├── [-rw-rw-r-- user  user    34K]  LICENSE
    ├── [-rw-rw-r-- user  user    186]  metadata.json
    └── [-rw-rw-r-- user  user   2.1K]  README.md

and the docker logs command gives:

PHP Warning:  scandir(/var/www/FreshRSS/extensions): Failed to open directory: Permission denied in /var/www/FreshRSS/lib/Minz/ExtensionManager.php on line 135
PHP Warning:  scandir(): (errno 13): Permission denied in /var/www/FreshRSS/lib/Minz/ExtensionManager.php on line 135
[Sun May 04 23:09:36.124211 2025] [mpm_prefork:notice] [pid 1:tid 1] AH00163: Apache/2.4.62 (Debian) configured -- resuming normal operations
[Sun May 04 23:09:36.124265 2025] [core:notice] [pid 1:tid 1] AH00094: Command line: 'apache2 -D FOREGROUND'
[Sun May 04 23:10:07.710583 2025] [php:warn] [pid 37:tid 37] [client 172.18.0.1:50384] PHP Warning:  scandir(/var/www/FreshRSS/extensions): Failed to open directory: Permission denied in /var/www/FreshRSS/lib/Minz/ExtensionManager.php on line 135, referer: http://localhost:8080/i/index.php?step=4
[Sun May 04 23:10:07.710614 2025] [php:warn] [pid 37:tid 37] [client 172.18.0.1:50384] PHP Warning:  scandir(): (errno 13): Permission denied in /var/www/FreshRSS/lib/Minz/ExtensionManager.php on line 135, referer: http://localhost:8080/i/index.php?step=4
[Sun May 04 23:10:09.708443 2025] [php:warn] [pid 37:tid 37] [client 172.18.0.1:50384] PHP Warning:  scandir(/var/www/FreshRSS/extensions): Failed to open directory: Permission denied in /var/www/FreshRSS/lib/Minz/ExtensionManager.php on line 135
[Sun May 04 23:10:09.708470 2025] [php:warn] [pid 37:tid 37] [client 172.18.0.1:50384] PHP Warning:  scandir(): (errno 13): Permission denied in /var/www/FreshRSS/lib/Minz/ExtensionManager.php on line 135
[Sun May 04 23:10:09.802723 2025] [php:warn] [pid 37:tid 37] [client 172.18.0.1:50384] PHP Warning:  scandir(/var/www/FreshRSS/extensions): Failed to open directory: Permission denied in /var/www/FreshRSS/lib/Minz/ExtensionManager.php on line 135
[Sun May 04 23:10:09.802748 2025] [php:warn] [pid 37:tid 37] [client 172.18.0.1:50384] PHP Warning:  scandir(): (errno 13): Permission denied in /var/www/FreshRSS/lib/Minz/ExtensionManager.php on line 135
[Sun May 04 23:10:09.832948 2025] [php:warn] [pid 37:tid 37] [client 172.18.0.1:50384] PHP Warning:  scandir(/var/www/FreshRSS/extensions): Failed to open directory: Permission denied in /var/www/FreshRSS/lib/Minz/ExtensionManager.php on line 135
[Sun May 04 23:10:09.832982 2025] [php:warn] [pid 37:tid 37] [client 172.18.0.1:50384] PHP Warning:  scandir(): (errno 13): Permission denied in /var/www/FreshRSS/lib/Minz/ExtensionManager.php on line 135
[Sun May 04 23:10:10.060206 2025] [php:warn] [pid 37:tid 37] [client 172.18.0.1:50384] PHP Warning:  scandir(/var/www/FreshRSS/extensions): Failed to open directory: Permission denied in /var/www/FreshRSS/lib/Minz/ExtensionManager.php on line 135
[Sun May 04 23:10:10.060254 2025] [php:warn] [pid 37:tid 37] [client 172.18.0.1:50384] PHP Warning:  scandir(): (errno 13): Permission denied in /var/www/FreshRSS/lib/Minz/ExtensionManager.php on line 135
[Sun May 04 23:10:10.122015 2025] [php:warn] [pid 37:tid 37] [client 172.18.0.1:50384] PHP Warning:  scandir(/var/www/FreshRSS/extensions): Failed to open directory: Permission denied in /var/www/FreshRSS/lib/Minz/ExtensionManager.php on line 135
[Sun May 04 23:10:10.122042 2025] [php:warn] [pid 37:tid 37] [client 172.18.0.1:50384] PHP Warning:  scandir(): (errno 13): Permission denied in /var/www/FreshRSS/lib/Minz/ExtensionManager.php on line 135
FreshRSS[37]: FreshRSS SimplePie GET 200 https://github.com/FreshRSS/FreshRSS/releases.atom
[Sun May 04 23:10:10.521986 2025] [php:warn] [pid 37:tid 37] [client 172.18.0.1:50384] PHP Warning:  scandir(/var/www/FreshRSS/extensions): Failed to open directory: Permission denied in /var/www/FreshRSS/lib/Minz/ExtensionManager.php on line 135
[Sun May 04 23:10:10.522002 2025] [php:warn] [pid 37:tid 37] [client 172.18.0.1:50384] PHP Warning:  scandir(): (errno 13): Permission denied in /var/www/FreshRSS/lib/Minz/ExtensionManager.php on line 135
[Sun May 04 23:10:10.552013 2025] [php:warn] [pid 37:tid 37] [client 172.18.0.1:50384] PHP Warning:  scandir(/var/www/FreshRSS/extensions): Failed to open directory: Permission denied in /var/www/FreshRSS/lib/Minz/ExtensionManager.php on line 135
[Sun May 04 23:10:10.552048 2025] [php:warn] [pid 37:tid 37] [client 172.18.0.1:50384] PHP Warning:  scandir(): (errno 13): Permission denied in /var/www/FreshRSS/lib/Minz/ExtensionManager.php on line 135
[Sun May 04 23:10:12.902830 2025] [php:warn] [pid 37:tid 37] [client 172.18.0.1:50384] PHP Warning:  scandir(/var/www/FreshRSS/extensions): Failed to open directory: Permission denied in /var/www/FreshRSS/lib/Minz/ExtensionManager.php on line 135
[Sun May 04 23:10:12.902873 2025] [php:warn] [pid 37:tid 37] [client 172.18.0.1:50384] PHP Warning:  scandir(): (errno 13): Permission denied in /var/www/FreshRSS/lib/Minz/ExtensionManager.php on line 135
FreshRSS[37]: FreshRSS Favicon GET https://github.com/FreshRSS/FreshRSS/
FreshRSS[37]: FreshRSS Favicon GET https://github.githubassets.com/favicons/favicon.svg
[Sun May 04 23:10:17.715481 2025] [php:warn] [pid 37:tid 37] [client 172.18.0.1:50384] PHP Warning:  scandir(/var/www/FreshRSS/extensions): Failed to open directory: Permission denied in /var/www/FreshRSS/lib/Minz/ExtensionManager.php on line 135
[Sun May 04 23:10:17.715505 2025] [php:warn] [pid 37:tid 37] [client 172.18.0.1:50384] PHP Warning:  scandir(): (errno 13): Permission denied in /var/www/FreshRSS/lib/Minz/ExtensionManager.php on line 135
FreshRSS[37]: FreshRSS GET json https://raw.githubusercontent.com/FreshRSS/Extensions/master/extensions.json
[Sun May 04 23:23:34.135235 2025] [mpm_prefork:notice] [pid 1:tid 1] AH00169: caught SIGTERM, shutting down
PHP Warning:  scandir(/var/www/FreshRSS/extensions): Failed to open directory: Permission denied in /var/www/FreshRSS/lib/Minz/ExtensionManager.php on line 135
PHP Warning:  scandir(): (errno 13): Permission denied in /var/www/FreshRSS/lib/Minz/ExtensionManager.php on line 135
[Sun May 04 23:23:35.046357 2025] [mpm_prefork:notice] [pid 1:tid 1] AH00163: Apache/2.4.62 (Debian) configured -- resuming normal operations
[Sun May 04 23:23:35.046417 2025] [core:notice] [pid 1:tid 1] AH00094: Command line: 'apache2 -D FOREGROUND'
[Sun May 04 23:23:45.853340 2025] [php:warn] [pid 36:tid 36] [client 172.18.0.1:50026] PHP Warning:  scandir(/var/www/FreshRSS/extensions): Failed to open directory: Permission denied in /var/www/FreshRSS/lib/Minz/ExtensionManager.php on line 135
[Sun May 04 23:23:45.853487 2025] [php:warn] [pid 36:tid 36] [client 172.18.0.1:50026] PHP Warning:  scandir(): (errno 13): Permission denied in /var/www/FreshRSS/lib/Minz/ExtensionManager.php on line 135
[Sun May 04 23:23:54.011339 2025] [php:warn] [pid 37:tid 37] [client 172.18.0.1:57542] PHP Warning:  scandir(/var/www/FreshRSS/extensions): Failed to open directory: Permission denied in /var/www/FreshRSS/lib/Minz/ExtensionManager.php on line 135
[Sun May 04 23:23:54.011387 2025] [php:warn] [pid 37:tid 37] [client 172.18.0.1:57542] PHP Warning:  scandir(): (errno 13): Permission denied in /var/www/FreshRSS/lib/Minz/ExtensionManager.php on line 135

Thanks

[Inverle]

Can you try running sudo chgrp -R 33 /home/user/.config/freshrss/extensions and then check http://localhost:8080/i/?c=extension&12345
?

Edit: make sure to run sudo chmod 755 /home/user/.config/freshrss/extensions too

[lnguyen4]

Can you try running sudo chgrp -R 33 /home/user/.config/freshrss/extensions and then check http://localhost:8080/i/?c=extension&12345 ?

Edit: make sure to run sudo chmod 755 /home/user/.config/freshrss/extensions too

Followed. But the extension still doesn't show up.

Here are the outputs from the earlier command

[drwxr-xr-x user  tape        36]  /home/user/.config/freshrss/extensions
└── [drwxrwxr-x user  tape       122]  xExtension-YouTube
    ├── [-rw-rw-r-- user  tape      1.8K]  configure.phtml
    ├── [-rw-rw-r-- user  tape      7.9K]  extension.php
    ├── [drwxrwxr-x user  tape        16]  i18n
    │   ├── [drwxrwxr-x user  tape        14]  de
    │   │   └── [-rw-rw-r-- user  tape       320]  ext.php
    │   ├── [drwxrwxr-x user  tape        14]  en
    │   │   └── [-rw-rw-r-- user  tape       298]  ext.php
    │   ├── [drwxrwxr-x user  tape        14]  fr
    │   │   └── [-rw-rw-r-- user  tape       352]  ext.php
    │   └── [drwxrwxr-x user  tape        14]  tr
    │       └── [-rw-rw-r-- user  tape       344]  ext.php
    ├── [-rw-rw-r-- user  tape       34K]  LICENSE
    ├── [-rw-rw-r-- user  tape       186]  metadata.json
    └── [-rw-rw-r-- user  tape      2.1K]  README.md

7 directories, 9 files

I think there is still something wrong with the permission setting :(

[Mon May 05 00:31:35.037144 2025] [php:warn] [pid 37:tid 37] [client 172.18.0.1:55584] PHP Warning:  scandir(/var/www/FreshRSS/extensions): Failed to open directory: Permission denied in /var/www/FreshRSS/lib/Minz/ExtensionManager.php on line 135
[Mon May 05 00:31:35.037166 2025] [php:warn] [pid 37:tid 37] [client 172.18.0.1:55584] PHP Warning:  scandir(): (errno 13): Permission denied in /var/www/FreshRSS/lib/Minz/ExtensionManager.php on line 135
[Mon May 05 00:31:55.114606 2025] [php:warn] [pid 55:tid 55] [client 172.18.0.1:60430] PHP Warning:  scandir(/var/www/FreshRSS/extensions): Failed to open directory: Permission denied in /var/www/FreshRSS/lib/Minz/ExtensionManager.php on line 135
[Mon May 05 00:31:55.114629 2025] [php:warn] [pid 55:tid 55] [client 172.18.0.1:60430] PHP Warning:  scandir(): (errno 13): Permission denied in /var/www/FreshRSS/lib/Minz/ExtensionManager.php on line 135
[Mon May 05 00:32:00.085154 2025] [php:warn] [pid 55:tid 55] [client 172.18.0.1:60430] PHP Warning:  scandir(/var/www/FreshRSS/extensions): Failed to open directory: Permission denied in /var/www/FreshRSS/lib/Minz/ExtensionManager.php on line 135
[Mon May 05 00:32:00.085187 2025] [php:warn] [pid 55:tid 55] [client 172.18.0.1:60430] PHP Warning:  scandir(): (errno 13): Permission denied in /var/www/FreshRSS/lib/Minz/ExtensionManager.php on line 135
[Mon May 05 00:32:06.149007 2025] [php:warn] [pid 62:tid 62] [client 172.18.0.1:56256] PHP Warning:  scandir(/var/www/FreshRSS/extensions): Failed to open directory: Permission denied in /var/www/FreshRSS/lib/Minz/ExtensionManager.php on line 135
[Mon May 05 00:32:06.149039 2025] [php:warn] [pid 62:tid 62] [client 172.18.0.1:56256] PHP Warning:  scandir(): (errno 13): Permission denied in /var/www/FreshRSS/lib/Minz/ExtensionManager.php on line 135
[Mon May 05 00:32:19.055019 2025] [php:warn] [pid 212:tid 212] [client 172.18.0.1:47892] PHP Warning:  scandir(/var/www/FreshRSS/extensions): Failed to open directory: Permission denied in /var/www/FreshRSS/lib/Minz/ExtensionManager.php on line 135
[Mon May 05 00:32:19.055100 2025] [php:warn] [pid 212:tid 212] [client 172.18.0.1:47892] PHP Warning:  scandir(): (errno 13): Permission denied in /var/www/FreshRSS/lib/Minz/ExtensionManager.php on line 135
PHP Warning:  scandir(/var/www/FreshRSS/extensions): Failed to open directory: Permission denied in /var/www/FreshRSS/lib/Minz/ExtensionManager.php on line 135
PHP Warning:  scandir(): (errno 13): Permission denied in /var/www/FreshRSS/lib/Minz/ExtensionManager.php on line 135
PHP Warning:  scandir(/var/www/FreshRSS/extensions): Failed to open directory: Permission denied in /var/www/FreshRSS/lib/Minz/ExtensionManager.php on line 135
PHP Warning:  scandir(): (errno 13): Permission denied in /var/www/FreshRSS/lib/Minz/ExtensionManager.php on line 135
[Mon May 05 00:34:09.628007 2025] [php:warn] [pid 38:tid 38] [client 172.18.0.1:35252] PHP Warning:  scandir(/var/www/FreshRSS/extensions): Failed to open directory: Permission denied in /var/www/FreshRSS/lib/Minz/ExtensionManager.php on line 135
[Mon May 05 00:34:09.628031 2025] [php:warn] [pid 38:tid 38] [client 172.18.0.1:35252] PHP Warning:  scandir(): (errno 13): Permission denied in /var/www/FreshRSS/lib/Minz/ExtensionManager.php on line 135

[Inverle]

I think there is still something wrong with the permission setting :(

Yes, it's a permission error, but I'm not exactly sure what's wrong.

edit: I meant sudo chmod -R 755 /home/user/.config/freshrss/extensions instead of sudo chmod 755 /home/user/.config/freshrss/extensions, so maybe that's why (forgot the -R flag)

check http://localhost:8080/i/?c=extension&534543 after running the new chmod command

if that won't fix it then:

what are the outputs of:

• sudo ps -Ao pid,user,command | egrep '(docker|container)'
• sudo docker exec freshrss ps -Ao pid,user,command
• sudo docker exec freshrss cat /etc/passwd | grep www-data

[lnguyen4]

• sudo docker exec freshrss cat /etc/passwd | grep www-data

Thanks a lot for helping so far. I sudo chmod with -R flag for the extensions dir but still it doesn't help. I restarted the docker daemon , restarted the freshrss container, but extension is not available to use.

Here is output of sudo ps -Ao pid,user,command | egrep '(docker|container)':

   1347 root     /usr/bin/containerd
   7168 root     /usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock --selinux-enabled --userland-proxy-path /usr/bin/docker-proxy --init-path /usr/bin/tini-static
   7472 root     /usr/bin/docker-proxy -proto tcp -host-ip 0.0.0.0 -host-port 8080 -container-ip 172.18.0.2 -container-port 80
   7481 root     /usr/bin/docker-proxy -proto tcp -host-ip :: -host-port 8080 -container-ip 172.18.0.2 -container-port 80
   7531 root     /usr/bin/containerd-shim-runc-v2 -namespace moby -id 8eeaff7747d68f6f7de9e8c214b4a70048cb9f48cefa28d62453b921078037b5 -address /run/containerd/containerd.sock
   7578 root     /usr/bin/containerd-shim-runc-v2 -namespace moby -id 5cc1752f33336fc9c8c77cfcb4442890d2dbc731e3103569c35fc15ddfbd0f25 -address /run/containerd/containerd.sock
   7582 root     /usr/bin/containerd-shim-runc-v2 -namespace moby -id fd3f1c8ab2710224f4b69cb84b0f8690472d5b14244a36188bfaa6027f4570be -address /run/containerd/containerd.sock
   8025 user  grep --color=auto -E --color=auto (docker|container)

sudo docker exec freshrss ps -Ao pid,user,command:

PID USER     COMMAND
      1 root     apache2 -D FOREGROUND
     30 root     cron
     34 root     /bin/sh /var/www/FreshRSS/cli/sensitive-log.sh
     35 root     sed -Eu s/([?&])(Passwd|token)=[^& \t]+/\1\2=redacted/ig
     36 www-data apache2 -D FOREGROUND
     37 www-data apache2 -D FOREGROUND
     38 www-data apache2 -D FOREGROUND
     39 www-data apache2 -D FOREGROUND
     40 www-data apache2 -D FOREGROUND
     41 www-data apache2 -D FOREGROUND
     42 root     CRON
     43 root     /bin/sh -c . /var/www/FreshRSS/Docker/env.txt; ..su www-data -s /bin/sh -c 'php /var/www/FreshRSS/app/actualize_script.php' ..2>> /proc/1/fd/2 > /tmp/FreshRSS.log
     44 root     su www-data -s /bin/sh -c php /var/www/FreshRSS/app/actualize_script.php
     45 www-data sh -c php /var/www/FreshRSS/app/actualize_script.php
     46 www-data php /var/www/FreshRSS/app/actualize_script.php
     88 root     ps -Ao pid,user,command

sudo docker exec freshrss cat /etc/passwd | grep www-data:

www-data:x:33:33:www-data:/var/www:/usr/sbin/nologin

[Inverle]

What about docker exec -u www-data freshrss ls -la extensions extensions/*?

Can you run docker exec -it www-data freshrss bash and cd into extensions?

Maybe you can edit this line in your docker-compose.yml

- ./extensions:/var/www/FreshRSS/extensions

to

- extensions:/var/www/FreshRSS/extensions

stop the container: docker stop freshrss and start it again
(without the ./)
and instead use docker cp to get your extensions into the container e.g.
docker cp /opt/Extensions/xExtension-YouTube/ freshrss:/var/www/FreshRSS/extensions/

This may have a better chance of working

[lnguyen4]

What about docker exec -u www-data freshrss ls -la extensions extensions/*?

I got

ls: cannot open directory 'extensions': Permission denied
ls: cannot open directory 'extensions/xExtension-YouTube': Permission denied

Can you run docker exec -it www-data freshrss bash and cd into extensions?

I ran docker exec -it -u www-data freshrss bash and got

www-data@freshrss:~/FreshRSS$ cd extensions/
www-data@freshrss:~/FreshRSS/extensions$ ls
ls: cannot open directory '.': Permission denied
www-data@freshrss:~/FreshRSS/extensions$ 

For - extensions:/var/www/FreshRSS/extensions in docker-compose.yml, I have done this way in another laptop and understood that this will create the volume freshrss_extensions, and whenever I want to install extension, i need to docker exec into the container and do the installation. Hence, when I try to set up this docker instance for my new laptop, I want to set up for extensions to work on host's but I know if not setting permissions correctly, it would be a headache.

One thing I want to ask: say, the extensions is set up as default - extensions: ... in docker-compose.yml, and most of the time, the extensions zip files are downloaded on the host, how can I do the installation (moving the dir) right on the host terminal without having to docker exec into the container shell?

[Inverle]

@lnguyen4

and most of the time, the extensions zip files are downloaded on the host, how can I do the installation (moving the dir) right on the host terminal without having to docker exec into the container shell?

As I wrote earlier, by using docker cp ;) (or you can also cd into /var/lib/docker/volumes/*_extensions/_data and copy it into there)

Regarding the earlier approach though:

Since you use Fedora, which has SELinux enabled by default, according to https://stackoverflow.com/questions/24288616/permission-denied-on-accessing-host-directory-in-docker the best solution is to use chcon -Rt svirt_sandbox_file_t /home/user/.config/freshrss/extensions, of course I have no idea if this will work so you can also try su -c "setenforce 0" if it doesn't.
Or alternatively, you can add a privileged: true line into your docker-compose.yml file, but this is a bad idea security wise.

Let me know if you are able to get extensions working with ./extensions

[Alkarex]

As @Inverle wrote, this is an issue due to a wrong SELinux configuration and permissions.
See (but may not apply to you directly, so just for inspiration) https://freshrss.github.io/FreshRSS/en/users/07_Frequently_Asked_Questions.html#permissions-under-selinux
and additional documentation welcome

[lnguyen4]

@Inverle @Alkarex , Thank you for providing help so far and giving some relevant info.

I am just a novice user for Fedora and know nothing about SELinux. I look up some to read , especially about docker and find this info about docker label for SELinux-enabled host: https://docs.docker.com/engine/storage/bind-mounts/#configure-the-selinux-label

Then, I decided to re-do the whole installation for this docker instance. From the link above, I use the :z option at the end of bind mount - ./extensions:/var/www/FreshRSS/extensions:z in docker-compose.yml file. Now, my docker instance is set up, and I can cp the extension dir into ./extensions so that the extension is available to use. I wonder if there is any side effect of using that :z option on bind mount. The link above warns against the :Z option for certain cases.

Thanks again,

[Alkarex]

Edit of our documentation welcome to add that link:

• https://github.com/FreshRSS/FreshRSS/blob/edge/docs/en/users/07_Frequently_Asked_Questions.md#permissions-under-selinux
• https://github.com/FreshRSS/FreshRSS/blob/edge/docs/fr/users/07_Frequently_Asked_Questions.md#g%C3%A9rer-les-permissions-sous-selinux