Starting non-GNOME wayland sessions through GDM leads to a user's PATH
being set to
/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
instead of /usr/local/bin:/usr/bin:/bin:/usr/local/games:/usr/games
(from /etc/profile).

Example: Starting sway or plasma-workspace-wayland through gdm and
trying to launch
lutris or gnome-chess only to find out that they won't start even
though they are
installed. It can take some time for a user to find out that the PATH
environment
variable is different.

This is a regression in bookworm and can surprise users upgrading from bullseye.

Possible workarounds are: Using a different display manager such as
sddm or starting
the wayland session through tty.

I first discovered this bug after installing lutris a few months
ago[0] and filed
a few bug reports[1][2]. As bookworm is about to be released, I thought it may
be worthwhile to document this unexpected behavior in its release notes.

0: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1028543
1: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=942131
2: https://gitlab.gnome.org/GNOME/gdm/-/issues/846

GDM imports system user environment variables.
This bug would likely be fixed by Debian (the systemd package?)
shipping a /usr/lib/systemd/user-environment-generators/ systemd user
environment generator with the default PATH Debian already set in
/etc/profile.
gnome-session importing /etc/profile is a temporary hack, so even for a
plain Gnome session this will not work forever without this fix.

Or ship an  /usr/lib/environment.d/*.conf file (which itself is read by
a systemd user environment generator : /usr/lib/systemd/user-
environment-generators/30-systemd-environment-d-generator).

Cheers,
Alban
PATH
from bullseye.
thought it may
notes.

I plan to check with the Debian systemd package maintainers about this option.

But
This might be the solution we're looking for. A
/usr/lib/environment.d/??-gdm3.conf file
provided by the gdm3 package?

On Mon, 29 Apr 2024 13:09:27 -0700 Jay <santosjaycee.0@gmail.com> wrote:
<alban.browaeys@gmail.com> wrote:
user
this option.
read by


No, in that it should not be named after gdm.
It is a bit far, but to me your issue is due to gdm3 not overwriting
the systemd user environment with its own PATH value anymore. This
means that you got things back working by reverting
https://gitlab.gnome.org/GNOME/gdm/-/commit/ccecd9c975d04da80db4cd547b67a1a94fa83292
because you made gdm3 overwrite the system user session environment
PATH value as it was doing before.
So the issue is that the systemd user enviroment is not set properly
for Debian specific PATH components (and that gdm3 does not overwrite
this systemd user session PATH value anymore if one is set, thus the
gdm3 fallback PATH mention in the patch. That is if no PATH value is
defined in the environment, then the old behavior of gdm setting it is
preserved, but if one is defined, then it is not changed).
Thus if you get the wrong PATH value it is not because gdm set it to
the wrong value, but because it stopped overweriting the bad value (in
that Debian requires a specific value that is not hte default and as no
Debian specific config has been provided, the default is wrong).


So the issue is, to me, Debian systemd specific and only involves gdm
because it has stopped overwriting the systemd default value (which is
wrong on Debian because Debian has specific path).

The Debian specific defaults are shown in /etc/profile
if [ "$(id -u)" -eq 0 ]; then
  PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
else
  PATH="/usr/local/bin:/usr/bin:/bin:/usr/local/games:/usr/games"
fi
export PATH


Debian systemd package just need to ship a config file to set this PATH
value.
So a /usr/lib/environment.d/??-debian.conf file shipped by the Debian
systemd package is what I deem the correct fix.

This bug report should be reassigned to systemd in my opinion.


So you were right that reverting commit ccecd9c9 would fix your issue,
but not because gdm added a bug but because it stopped hiding an
underlying "bug" (well wrong default PATH value in systemd for Debian).
It could be that systemd maintainers thing this is gdm job to overwrite
their value, though it looks more correct to me to bug them first as
they are the one setting the wrong default for Debian (or so I believe,
I have not checked extensively if the wrong PATH default value could be
fine at the systemd level and be changed afterwards).

Cheers,
Alban

Thanks again! I finally found some time to further investigate this.
I have reassigned this bug report to the systemd package,
but it looks like base-files and libpam-modules are the packages
involved.

My Debian system was installed in 2022-10. To be sure this wasn't
just a misconfigured system in 2022, I checked again with a fresh
Debian 12.5 install and found that the same defaults are present.
Reading that made me check Ubuntu's defaults:
/etc/environment
PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin"
/etc/profile
(no mention of PATH)

It looks like Ubuntu sets PATH in /etc/environment through libpam-modules
and /usr/lib/environment.d/99-environment.conf is symlinked to it.
Debian sets PATH in /etc/profile through base-files and its
/usr/lib/environment.d/99-environment.conf
is symlinked to an empty /etc/environment also created by libpam-modules.

Ubuntu's libpam-modules runs a postinst script:
# Add PATH to /etc/environment if it's not present there or in
# /etc/security/pam_env.conf
if [ "$1" = "configure" ] && dpkg --compare-versions "$2" lt
1.3.1-5ubuntu5; then
    if ! grep -qs ^PATH "$DPKG_ROOT"/etc/security/pam_env.conf; then
        if ! grep -qs ^PATH= "$DPKG_ROOT"/etc/environment; then
            echo
'PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin"'
        fi
    fi
fi

Debian's libpam-modules postinst:
if dpkg --compare-versions "$2" lt 0.99.9.0-1 && ! [ -f
"$DPKG_ROOT"/etc/environment ]
then
     touch "$DPKG_ROOT"/etc/environment
fi

I think we can narrow this down to base-files and/or libpam-modules.
I'm not sure if doing the same thing as the Ubuntu package would be
the right thing
so I'm CC'ing the maintainers for both packages and the debian-desktop
mailing list
for advice instead of reassigning the bug report again.

Hello.

My plan for base-files is to stop overriding the PATH in /etc/profile.

Ubuntu did that a long time ago and it's probably the right thing to do.

I'd like to do this for trixie, but only after the t64 transition is finished
and the usr-merge patch from Helmut Grohne is implemented.

Also, I want to be sure that nothing breaks, and if it does, I want to be
sure that I'm not forced to set the PATH again. See what happened the last
time I tried :-)

https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=571086

Thanks.

Note that /etc/profile is a configuration file for bourne shells. While it's a
common path, it's not especially for other shells (I think zsh still uses it
but not all I think) and not graphical sessions.

Regards,

    Santiago> Hello.  My plan for base-files is to stop overriding the
    Santiago> PATH in /etc/profile.

    Santiago> Ubuntu did that a long time ago and it's probably the
    Santiago> right thing to do.

I'd be happy to pick up the Ubuntu patch to include PATH in
/etc/environment for libpam-modules.

It would probably be best to leave /etc/profile as it is. I expected
my wayland desktop session to have
its PATH match the /etc/profile PATH for non-root shells, so I guess
libpam-modules is the package I was
looking for.

I have been testing the following changes locally. It is a variation
based on Ubuntu's libpam-modules.postinst.

*** Debian_salsa/pam/debian/libpam-modules.postinst     2025-02-11
10:13:55.525742196 -0800
--- Debian_salsa_modified/pam/debian/libpam-modules.postinst
2025-02-11 10:29:26.369651525 -0800
***************
*** 16,19 ****
--- 16,29 ----
       touch "$DPKG_ROOT"/etc/environment
 fi

+ # Add PATH to /etc/environment if it's not present there or in
+ # /etc/security/pam_env.conf
+ if [ "$1" = "configure" ] && dpkg --compare-versions "$2" lt 1.7.0-4; then
+       if ! grep -qs ^PATH "$DPKG_ROOT"/etc/security/pam_env.conf; then
+               if ! grep -qs ^PATH= "$DPKG_ROOT"/etc/environment; then
+                       echo
'PATH="/usr/local/bin:/usr/bin:/bin:/usr/local/games:/usr/games"' >>
"$DPKG_ROOT"/etc/environment
+               fi
+       fi
+ fi
+
 #DEBHELPER#