Dev1 Galaxy Forum / Running Firefox in Firejail

Re: Running Firefox in Firejail

dummy@example.com (onedevone) — Fri, 06 Mar 2026 08:29:58 +0000

Can you confirm that you can run:

$ firejail -seccomp falkon

with all related (profiles) to firejail installed?
Does it fail?

Re: Running Firefox in Firejail

dummy@example.com (zapper) — Sat, 03 Jan 2026 11:32:22 +0000

I always run my web browser through firejail like this:

firejail --nogroups --caps.drop=all --private-tmp --private-dev --seccomp --noroot --disable-mnt librewolf

Re: Running Firefox in Firejail

dummy@example.com (fsmithred) — Fri, 02 Jan 2026 13:43:07 +0000

Same as mine.

lrwxrwxrwx 1 root root 36 Aug 10  2024 /etc/localtime -> /usr/share/zoneinfo/America/New_York

Target file is also owned by root here:

-rw-r--r-- 1 root root 3552 Aug 24 16:12 /usr/share/zoneinfo/America/New_York

Check the size of fcopy, too. I'm running the same version, so it should be the same size.

$ ls -l /usr/lib/x86_64-linux-gnu/firejail/fcopy 
-rwx--x--x 1 root root 30968 Apr 20  2025 /usr/lib/x86_64-linux-gnu/firejail/fcopy

Similar problem solved here:
https://discussion.fedoraproject.org/t/ … tes/161848

Re: Running Firefox in Firejail

dummy@example.com (VH) — Fri, 02 Jan 2026 01:21:26 +0000

It says:

lrwxrwxrwx   1 root root      36 Dec 28 09:09 localtime -> /usr/share/zoneinfo/America/New_York

Re: Running Firefox in Firejail

dummy@example.com (fsmithred) — Mon, 29 Dec 2025 16:08:18 +0000

I get the same output as you up until this line:

Error fcopy: invalid ownership for file /etc/localtime

What does 'ls -l' have to say about that file? (Mine is a symlink owned by root.)

Running Firefox in Firejail

dummy@example.com (VH) — Mon, 29 Dec 2025 02:44:00 +0000

Hello,

I always ran firefox in firejail with Daedalus.

I installed Excalibur and tried to do the same thing but it gives me the error message.

I ran firefox like this:
"admin@MySys:~$firejail --seccomp firefox"
but it gave me errors. So I ran
"admin@MySys:~$firejail firefox"
but it still gave me errors. What can I dd? Below is the result.

admin@MySys:~$ firejail --seccomp firefox
Reading profile /etc/firejail/firefox.profile
Reading profile /etc/firejail/firefox-common.profile
Reading profile /etc/firejail/disable-common.inc
Reading profile /etc/firejail/disable-devel.inc
Reading profile /etc/firejail/disable-exec.inc
Reading profile /etc/firejail/disable-interpreters.inc
Reading profile /etc/firejail/disable-proc.inc
Reading profile /etc/firejail/disable-programs.inc
Reading profile /etc/firejail/whitelist-common.inc
Reading profile /etc/firejail/whitelist-run-common.inc
Reading profile /etc/firejail/whitelist-runuser-common.inc
Reading profile /etc/firejail/whitelist-usr-share-common.inc
Reading profile /etc/firejail/whitelist-var-common.inc
Warning: networking feature is disabled in Firejail configuration file
firejail version 0.9.74

Seccomp list in: !chroot, check list: @default-keep, prelist: unknown,
Parent pid 2812, child pid 2817
Warning: An abstract unix socket for session D-BUS might still be available. Use --net or remove unix from --protocol set.
Error fcopy: invalid ownership for file /etc/localtime
Error: failed to run /run/firejail/lib/fcopy, exiting...
Error: proc 2812 cannot sync with peer: unexpected EOF
Peer 2817 unexpectedly exited with status 1

admin@MySys:~$ firejail firefox
Reading profile /etc/firejail/firefox.profile
Reading profile /etc/firejail/firefox-common.profile
Reading profile /etc/firejail/disable-common.inc
Reading profile /etc/firejail/disable-devel.inc
Reading profile /etc/firejail/disable-exec.inc
Reading profile /etc/firejail/disable-interpreters.inc
Reading profile /etc/firejail/disable-proc.inc
Reading profile /etc/firejail/disable-programs.inc
Reading profile /etc/firejail/whitelist-common.inc
Reading profile /etc/firejail/whitelist-run-common.inc
Reading profile /etc/firejail/whitelist-runuser-common.inc
Reading profile /etc/firejail/whitelist-usr-share-common.inc
Reading profile /etc/firejail/whitelist-var-common.inc
Warning: networking feature is disabled in Firejail configuration file
firejail version 0.9.74

Seccomp list in: !chroot, check list: @default-keep, prelist: unknown,
Parent pid 2832, child pid 2836
Warning: An abstract unix socket for session D-BUS might still be available. Use --net or remove unix from --protocol set.
Error fcopy: invalid ownership for file /etc/localtime
Error: failed to run /run/firejail/lib/fcopy, exiting...
Error: proc 2832 cannot sync with peer: unexpected EOF
Peer 2836 unexpectedly exited with status 1

Thanks in advance.