usr.bin.firefox blocks /dev/shm

[Jean-Philippe Guérard]

When apparmor is activated for Firefox, I get the following log messages:

[28547.841769] audit: type=1400 audit(1442154214.608:109): apparmor="DENIED" operation="mknod" profile="/usr/lib/firefox/firefox{,*[^s][^h]}" name="/dev/shm/shmfd-mSnoHU" pid=7425 comm
="firefox" requested_mask="c" denied_mask="c" fsuid=1111 ouid=1111

Both /run/shm/shmfd-* and /var/run/shm/shmfd-* are allowed, but not /dev/shm/shmfd-*.

Changing :

owner /{,var/}run/shm/shmfd-* rw,

To:

owner /{dev,{,var/}run}/shm/shmfd-* rw,

seems to fix the issue.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Thomas Mayer (thomas303)]

Patch available in https://bugs.launchpad.net/ubuntu/+source/firefox/+bug/1659988

[Simon Déziel (sdeziel)]

@Jean-Philippe, I use the Firefox profile extensively with some additional local/ rules (LP: #1533232) but I never ran into a situation where Firefox needed to access /dev/shm. Could you double check if you still have those denial on a fully updated system? Thanks

[Jean-Philippe Guérard (fevrier)]

I was able to reproduce the problem, but only using the flash plugin:

Jan 31 23:38:34 tigreraye kernel: [221147.141240] audit: type=1400 audit(1485902314.881:3406): apparmor="DENIED" operation="mknod" profile="/usr/lib/firefox/firefox{,*[^s][^h]}" name="/dev/shm/org.chromium.CvbXEt" pid=11592 comm="plugin-containe" requested_mask="c" denied_mask="c" fsuid=1000 ouid=1000
Jan 31 23:38:34 tigreraye kernel: [221147.141263] audit: type=1400 audit(1485902314.881:3407): apparmor="DENIED" operation="mknod" profile="/usr/lib/firefox/firefox{,*[^s][^h]}" name="/dev/shm/org.chromium.5Am9iK" pid=11592 comm="plugin-containe" requested_mask="c" denied_mask="c" fsuid=1000 ouid=1000

I also tried the java plugin, but it does not use /dev/shm (it fails, but for another reason):

Jan 31 23:43:49 tigreraye kernel: [221461.300441] audit: type=1400 audit(1485902629.062:6116995): apparmor="DENIED" operation="exec" profile="/usr/lib/firefox/firefox{,*[^s][^h]}" name="/usr/lib/jvm/java-8-oracle/jre/bin/java" pid=11779 comm="plugin-containe" requested_mask="x" denied_mask="x" fsuid=1000 ouid=0
Jan 31 23:43:49 tigreraye kernel: [221461.301683] audit: type=1400 audit(1485902629.062:6116996): apparmor="DENIED" operation="exec" profile="/usr/lib/firefox/firefox{,*[^s][^h]}" name="/usr/lib/jvm/java-8-oracle/jre/bin/java" pid=11780 comm="plugin-containe" requested_mask="x" denied_mask="x" fsuid=1000 ouid=0

[Simon Déziel (sdeziel)]

On 2017-01-31 05:46 PM, Jean-Philippe Guérard wrote:
> I was able to reproduce the problem, but only using the flash plugin:
>
> Jan 31 23:38:34 tigreraye kernel: [221147.141240] audit: type=1400 audit(1485902314.881:3406): apparmor="DENIED" operation="mknod" profile="/usr/lib/firefox/firefox{,*[^s][^h]}" name="/dev/shm/org.chromium.CvbXEt" pid=11592 comm="plugin-containe" requested_mask="c" denied_mask="c" fsuid=1000 ouid=1000
> Jan 31 23:38:34 tigreraye kernel: [221147.141263] audit: type=1400 audit(1485902314.881:3407): apparmor="DENIED" operation="mknod" profile="/usr/lib/firefox/firefox{,*[^s][^h]}" name="/dev/shm/org.chromium.5Am9iK" pid=11592 comm="plugin-containe" requested_mask="c" denied_mask="c" fsuid=1000 ouid=1000

Good, thanks for the additional information.

> I also tried the java plugin, but it does not use /dev/shm (it fails,
> but for another reason):
>
> Jan 31 23:43:49 tigreraye kernel: [221461.300441] audit: type=1400 audit(1485902629.062:6116995): apparmor="DENIED" operation="exec" profile="/usr/lib/firefox/firefox{,*[^s][^h]}" name="/usr/lib/jvm/java-8-oracle/jre/bin/java" pid=11779 comm="plugin-containe" requested_mask="x" denied_mask="x" fsuid=1000 ouid=0
> Jan 31 23:43:49 tigreraye kernel: [221461.301683] audit: type=1400 audit(1485902629.062:6116996): apparmor="DENIED" operation="exec" profile="/usr/lib/firefox/firefox{,*[^s][^h]}" name="/usr/lib/jvm/java-8-oracle/jre/bin/java" pid=11780 comm="plugin-containe" requested_mask="x" denied_mask="x" fsuid=1000 ouid=0

Yeah, it seems like the Oracle version of the JRE/JDK isn't authorized
in /etc/apparmor.d/abstractions/ubuntu-browsers.d/java. Even OpenJDK/JRE
8 isn't authorized. Both should be supported IMHO.

Thanks,
Simon

[Thomas Mayer (thomas303)]

I had the /dev/shm/org.chromium.XXXXXX issues with

- Flash plugin DISABLED
- Java plugin DISABLED

Maybe playing a HTML5 youtube video exposes it.

I'm on ubuntu 16.04 (up-to-date), FF 51.0.1, with apparmor profile activated.

@fevrier Have you tried my patch (version 6) (taken from https://bugs.launchpad.net/bugs/1659988)?

I did not try with Java/Flash support, but your log entries look as if my patch covers that, too.