Bug#879906: gnome-session: freezes after start when network is up but under captive portal

[Cyrille Chépélov]

Package: gnome-session
Version: 3.24.1-2
Severity: important

Dear Maintainer,

When starting a session with (wifi) network up **but** locked out of 
actual connectivity (a situation which happens in many "free" wifi spaces),
gnome-session will accept the logon, show a grey background with a mouse 
(but not the specified screen background) and sit idle.

Steps to reproduce:
   - purchase a return SNCF high-speed train ticket from Paris to Lyon
   - take the Paris→Lyon train
   - connect to their wifi ("_SNCF_WIFI_INOUI")
   - go to the captive portal page, and authenticate using your train 
ticket reference & name
   - when in Lyon, shut the laptop down entirely

   - sit down on the return train Lyon→Paris
   - start the laptop
   - attempt to log in.
      ** in background, Network-Manager will immediately reconnect to 
_SNCF_WIFI_INOUI, which will deny service (and lie over DNS) until the 
user has
         visited the captive portal and entered the train ticket 
reference & name
      ** user cannot visit as gnome-session will freeze (with mouse 
active) and not leave a chance to start a browser
      ** user cannot use links or another text-mode browser as the 
captive portal will reject it.

This situation can be reproduced in many similar settings, including 
cybercafes, airports, co-working spaces.

(annoying) Workaround:
    * start the laptop
    * switch to the text-mode console
    * "rfkill block" out the wifi interface
    * log into gnome-session
    * unblock the wifi, start firefox, log into the captive portal

Thanks in advance


-- System Information:
Debian Release: buster/sid
   APT prefers testing
   APT policy: (800, 'testing'), (600, 'unstable'), (400, 'stable')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 4.13.0-1-amd64 (SMP w/8 CPU cores)
Locale: LANG=fr_FR.UTF-8, LC_CTYPE=fr_FR.UTF-8 (charmap=UTF-8), 
LANGUAGE=fr_FR.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages gnome-session depends on:
ii  gnome-session-bin      3.24.1-2
ii  gnome-session-common   3.24.1-2
ii  gnome-settings-daemon  3.24.3-1
ii  gnome-shell            3.22.3-3

gnome-session recommends no packages.

Versions of packages gnome-session suggests:
ii  desktop-base      9.0.5
ii  gnome-keyring     3.20.1-1
ii  gnome-user-guide  3.26.1.1-1

-- no debconf information
(END)