Ubuntu 18.04 and Permission denied when connecting Sunto Vyper with usb

[Audun Hansen]

After upgrading to Ubuntu 18.04 (freshinstall) and Subsurface 4.8.1, I got trouble with communications with my computer.

Following message found in /var/log/syslog:

 systemd-udevd[5463]: Process '/usr/lib/snapd/snap-device-helper bind snap_subsurface_subsurface /devices/pci0000:00/0000:00:14.0/usb2/2-6 189:131' failed with exit code 1.

 subsurface_subsurface.desktop[5088]: [0.000016] ERROR: Permission denied (13) [in serial_posix.c:295 (dc_serial_open)]

What i found:

# ls -latr /dev/ttyUSB0
crw-rw---- 1 root dialout 188, 0 aug.   9 23:44 /dev/ttyUSB0          <---  look at owner and permissionss

Dirtyfix, works just as long as the computer is connected:

# chown <my_username> /dev/ttyUSB0

Then import of dives works.

This seems like a Ubuntu spesific permission problem(?)

[Linus Torvalds]

On Thu, Aug 9, 2018 at 3:45 PM Audun Hansen <audu...@gmail.com> wrote:
>
> This seems like a Ubuntu spesific permission problem(?)

No, it's mentioned in the manual.

Make yourself part of the dialout group to get serial line access, and
then it's not a temporary fix any more.

Something like

sudo usermod -a -G dialout <username>

or similar.

Linus

[Eloy Anguiano]

 Dear Linus,

I am a linux user since 1992 and have experience as a linux administrator. In fact I have been director of the Linux Reference Center UAM-IBM for 10 years. 

As soon as the error occurred (and you know, without reading the manual, hahaha), I added myself to the dialout group and yet I still can't access /dev/ttyUSB0 which is where my Mares Puck Pro is mounted. In case there were any group update problem (which I shouldn't have, but just to be sure) I ran a new bash from the bash where I ran subsurface.

It is not a protocol problem because by running as root I can access and download the dives. I don't know what other problem there might be.

Just to check it out:

eloy@amaltea:~$ cat /etc/group | grep dialout

dialout:x:20:eloy

eloy@amaltea:~$ ls /dev/ttyUSB0 -la

crw-rw------ 1 root dialout 188, 0 Sep 3 21:10 /dev/ttyUSB0

I'd appreciate any indication.

Thank you very much for your attention.

[Linus Torvalds]

On Mon, Sep 3, 2018 at 12:20 PM Eloy Anguiano <eloy.a...@gmail.com> wrote:
>
> As soon as the error occurred (and you know, without reading the manual, hahaha), I added myself to the dialout group and yet I still can't access /dev/ttyUSB0 which is where my Mares Puck Pro is mounted. In case there were any group update problem (which I shouldn't have, but just to be sure) I ran a new bash from the bash where I ran subsurface.

You'd need to log in anew to get the group update, since it's the
login process that gives users permissions.

> It is not a protocol problem because by running as root I can access and download the dives. I don't know what other problem there might be.

That really indicates that it is just a permission issue, since it
works as root. So subsurface works fine in theory.

You could try to do the whole "strace -f" thing and then look for
ttyUSB0 in the resulting filesystem trace.

> Just to check it out:
>
> eloy@amaltea:~$ cat /etc/group | grep dialout
> dialout:x:20:eloy
> eloy@amaltea:~$ ls /dev/ttyUSB0 -la
> crw-rw------ 1 root dialout 188, 0 Sep 3 21:10 /dev/ttyUSB0

The real check would be to run 'id':

[torvalds@i7 ~]$ id
uid=1000(torvalds) gid=1000(torvalds)
groups=1000(torvalds),10(wheel),18(dialout)
context=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023

and checking that the dialout group is listed for your current shell session.

There *might* be some odd Ubuntu apparmor rule etc that keeps even
dialout from actually opening things. Ubuntu has had those kinds of
oddities before. See for example

https://bugs.launchpad.net/ubuntu/+source/cups/+bug/677432

and if it's apparmor you should see some kind of audit log about it in
your system logs,

audit: ...: apparmor="DENIED" operation="open" .. name="/dev/ttyUSB0" ..

but I don't run Ubuntu and don't know what their security settings are.

So if it's not the dialout thing, you need to check the ubuntu forums
for apparmor.

Linus

Linus

[Eloy Anguiano]

Dear Linus

Problem solved. The problem was with apparmor. 

Thank you so much for your attention.

[Dirk Hohndel]

> On Sep 3, 2018, at 4:26 PM, Eloy Anguiano <eloy.a...@gmail.com> wrote:
>
>
> Problem solved. The problem was with app armor.

Can you share the solution so we can document this for others?

Thanks

/D