bug#38651: connman integration issue after recent updates

bug#38651: connman integration issue after recent updates

[Reza Alizadeh Majd]

Hi Guix, 

I'm using `connman` + `cmst` for network management on my guix machine, recently after I updated the system, I receive following message after login and `cmst` can't communicate with `connman`. I also  tried with `econnman` interface and received same error: 

```
Error Name: org.freedesktop.DBus.Error.AccessDenied

Error Message: Rejected send message, 3 matched rules; type="method_call", sender=":1.108" (uid=1000 pid=3870 comm="cmst ") interface="net.connman.Manager" member="GetTechnologies" error name="(unset)" requested_reply="0" destination="net.connman" (uid=0 pid=369 comm="/gnu/store/1ld7hpvnhcr5wjxd15bvgbwvd50j8i04-connma")
```

I also tried to modify `connman` package and add 

<allow send_interface="net.connman.Manager"/>

policy to connman debus config, based on suggested details in: 
https://forum.obarun.org/viewtopic.php?pid=3075#p3075

but the problem still occurs. 

--
Regards
Reza Alizadeh Majd
PantherX Team

bug#38651: connman integration issue after recent updates

[Reza Alizadeh Majd]

here is a sample configuration file that I used to reproduce the issue:

(use-modules (gnu)
             (gnu system nss)
             (gnu packages gnome)
             (gnu packages vim)
             (srfi srfi-1))

(use-service-modules desktop networking ssh xorg)
(use-package-modules screen ssh certs tls connman)

(operating-system
  (host-name "panther")
  (timezone "Asia/Tehran")
  (locale "en_US.utf8")

  ;; Boot in "legacy" BIOS mode
  (bootloader (bootloader-configuration
                (bootloader grub-bootloader)
                (target "/dev/sda")))
  (file-systems (cons (file-system
                        (device (file-system-label "my-root"))
                        (mount-point "/")
                        (type "ext4"))
                      %base-file-systems))

  (users (cons (user-account
                 (name "user")
                 (comment "default user")
                 (group "users")
                 (supplementary-groups '("wheel" "audio" "video"))
                 (home-directory "/home/user"))
                %base-user-accounts))

  (packages (cons* openssh nss-certs gnutls cmst
                   %base-packages))

  (services (cons* (service gnome-desktop-service-type)
                   (service openssh-service-type
                            (openssh-configuration
                              (port-number 22)
                              (permit-root-login #t)
                              (authorized-keys
                                `(("user" ,(local-file "/etc/vagrant.pub"))
                                  ("root" ,(local-file "/etc/vagrant.pub"))))))
                   (service connman-service-type)
                   (remove (lambda (service)
                             (eq? (service-kind service) network-manager-service-type))
                           %desktop-services)))

  (name-service-switch %mdns-host-lookup-nss))

--
Regards
Reza Alizadeh Majd
PantherX Team