Accessing www-data when logged in as another user

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1

I want to describe what is my problem :slight_smile:

I would like to open a specific program with the www-data user via Putty with X11 Forwarding. With the “pi” user it worked after I set the entry “X11Forwarding” to yes in sshd.conf. So when I log in to my Raspberry via Putty and user pi (with X11 forwarding setting), start a GUI program from there it works fine.

With this program I want to access ncdata, which unfortunately is not possible because this directory belongs to the www-data account.

Therefore I tried to execute this command with the following command (after logging into my Raspberry with the pi user (and X11 forwarding):
pi@nextcloudpi:~ $ sudo runuser -l www-data -c fslint-gui

ERROR:
/usr/lib/python2.7/dist-packages/gtk-2.0/gtk/ init .py:57: GtkWarning: could not open display
warnings.warn(str(e), _gtk.Warning)
/usr/bin/fslint-gui:268: Warning: invalid (NULL) pointer instance
self.widgets = gtk.glade.XML(Filename, WindowName, gettext.textdomain())
/usr/bin/fslint-gui:268: Warning: g_signal_connect_data: assertion ‘G_TYPE_CHECK_INSTANCE (instance)’ failed

That works with the pi user, but in the above Command I use the www-data for the call and then the GTK error message appears, which probably has something to do with X11, since the www-data user has a “nologin” flag and no bash.

That’s why I’m now trying to fix this error - which is actually a Linux-relevant topic, as JimmyKater has already mentioned.

Big thanks to JimmyKater !!!

1 Like
2

Login and shell are disabled by default for very good security reasons for www-data.

I would strongly advise against it for that reason. It would create a vulnerability.
Would you please clarify; why you want or need to access ncdata in Gui program (and which one), you already have the webinterface for that.What function(s) are you missing there.

3

what about login with your standard user and then :
sudo -u www-data

4

How are you going to sudo -u in a GUI or plan to run a terminal inside of it? :rofl:

5

yeaaa in GUI it will not work … :grinning:

6

How about adding your pi user to the www-data group allowing him to read all Nextcloud files

sudo adduser pi www-data