nscd daemon caches queries made to NSS via glibc. In our case queries to passwd
and group databases are cached. But this leads to many problems.
See: https://salsa.debian.org/freedombox-team/freedombox/-/merge_requests/2520
The bug that this MR fixes, that is, the inaccuracy of the authentication data,
is horrible and only acceptable if the caching provides very important
functionality. Already, having to purge nscd caches after modifying user
accounts is not nice.
I believe that we have encountered this bug before and blamed libpam-abl due to
the time sensitive nature of the problem.
nscd itself recommends that it should be used if NSS lookup are expensive (such
as in case of NIS, NIS+ queries according to /etc/init.d/nscd). In case of
FreedomBox, LDAP queries are unlikely to be made using network. LDAP server is
likely always local. I believe we can safely remove nscd by masking and stopping
nscd.service and unscd.service.
Tests:
- After applying the patches, users app setup is re-run. Service nscd is stopped
and masked. unscd is also masked.
- Running 'id tester' shows expected value 'uid=10001(tester) gid=100(users)
groups=100(users),10002(admin)'.
- Adding, removing, renaming a user immediately reflects in 'id <user>'.
- Adding and removing a user from groups immediately reflects in 'id <user>'.
Signed-off-by: Sunil Mohan Adapa <sunil@medhas.org>
Reviewed-by: Veiko Aasa <veiko17@disroot.org>
Fixes an issue where LDAP group membership info is not available long time
after system restart. This can happen when nscd cache is expired and name
service queries are made while nslcd is not yet started. As a result, nscd
group cache contains only local system groups and not LDAP groups. The issue
arises more likely in slow systems where slapd/nslcd startup can take minutes.
Could also depend on how long the device has been shut down before.
Tests performed:
- stop nscd service, start nslcd service, check form the logs that
nscd reload errors are ignored and nslcd service starts successfully.
- Test when nscd group cache is invalidated while nslcd is not running.
Run commands:
```
systemctl reload nscd
id tester
systemctl stop nslcd
nscd -i group
id tester
systemctl start nslcd
id tester
```
Result before patch applied.
```
uid=10001(tester) gid=100(users) groups=10002(admin),100(users)
uid=10001(tester) gid=100(users) groups=100(users)
uid=10001(tester) gid=100(users) groups=100(users)
```
Result after patch applied, tester is in the admins group at the end.
```
uid=10001(tester) gid=100(users) groups=10002(admin),100(users)
uid=10001(tester) gid=100(users) groups=100(users)
uid=10001(tester) gid=100(users) groups=10002(admin),100(users)
```
Signed-off-by: Veiko Aasa <veiko17@disroot.org>
Reviewed-by: Sunil Mohan Adapa <sunil@medhas.org>
Tests:
- Config files are all symlinks in /etc/
- LDAP auth works for /tt-rss-app/
Signed-off-by: Sunil Mohan Adapa <sunil@medhas.org>
Reviewed-by: James Valleroy <jvalleroy@mailbox.org>
- This will leave /etc/{plinth,freedombox} empty by default making service more
robust to run across various environments and situations. See systemd's
explanation for more details.
- Use Debian maintainer scripts remove all the existing files in
/etc/plinth/modules-enabled.
- Read from /usr/share/freedombox/modules-enabled then from
/etc/plinth/modules-enabled and finally from /etc/freedombox/modules-enabled.
Later read ones override previously read files. Any file pointing to /dev/null
will mean the module must be ignored.
Tests:
- Clean up /etc/plinth, /etc/freedombox and
/usr/share/freedombox/modules-enabled. Run service and notice that files are
getting loaded from development folder using a debug message.
- Run setup.py and notice that files get installed in
/usr/share/freedombox/modules-enabled/ and in the next run they get loaded from
there.
- Create a override file in /etc/plinth/modules-enabled/transmission and notice
that overriden file gets priority over the one in
/usr/share/freedombox/modules-enabled.
- Link the file /etc/plinth/modules-enabled/transmission to /dev/null and notice
that is not loaded.
- Create another file in /etc/freedombox/modules-enabled/transmission and notice
that it overrides the previous two files.
- All affected modules are loaded.
- Build a new Debian package and ensure that upgrading 23.8 to new version
removes are all configuration files.
- Build developer documentation and test that Tutorial -> Full Code and Tutorial
-> Skeleton sections have been updated with references to
-.../modules-enabled/... paths.
- Install quassel and notice that certificates were copied to /var/lib/quassel
directory. Change domain to another domain and notice that certificates were
copied again to that directory.
Reviewed-by: James Valleroy <jvalleroy@mailbox.org>
