Due to recent changes (likely a sqlite3 update) the sqlite3 meta-command
did suddenly succeed while sqlite3 is still unable to read the still
encrypted database. It just prints the following output and doesn't
seem to try to open/read the DB (which would fail):
```
main: /home/alice/.config/Signal/sql/db.sqlite r/w
```
We can simply fix this "regression" by instructing sqlite3 to list the tables
in the database (which fails because it cannot read the encrypted DB):
```
machine: must fail: su - alice -c 'sqlite3 ~/.config/Signal/sql/db.sqlite .tables'
machine # [ 47.036720] su[1178]: Successful su for alice by root
machine # [ 47.041049] su[1178]: pam_unix(su:session): session opened for user alice(uid=1000) by (uid=0)
machine # Error: file is not a database
machine # [ 47.116070] su[1178]: pam_unix(su:session): session closed for user alice
(finished: must fail: su - alice -c 'sqlite3 ~/.config/Signal/sql/db.sqlite .tables', in 0.12 seconds)
```
Fix#181463.
the default hasn't been changed since 2009
this can improve our test performances
nixos/tests: remove explicit memorySize <1024
1024MiB is now the default
AFAIK this is the only reliable way for us to ensure SQLCipher will be
loaded instead of SQLite. It feels like a hack/workaround but according
to the SQLCipher developers [0] "this issue can and should be handled
downstream at the application level: 1. While it may feel like a
workaround, using LD_PRELOAD is a legitimate approach here because it
will substitute the system SQLite with SQLCipher which is the intended
usage model;".
This fixes#108772 for NixOS 20.09 users who upgrade to NixOS 21.05 and
replaces #117555.
For nixos-unstable users this will unfortunately break everything again
so we should add a script to ease the transition (in a separate commit
so that we can revert it for NixOS 21.05).
[0]: https://github.com/sqlcipher/sqlcipher/issues/385#issuecomment-802874340
Well, this should test if the database is encrypted but currently it is
still unencrypted and we need to notice if this behaviour changes in the
future (as it will cause data loss, see e.g. #108772).
Anyway, this doesn't really matter for security reasons but we need this
test to prevent data loss (unfortunately Signal-Desktop and SQLCipher
handle this badly... :o).
This module allows root autoLogin, so we would break that for users, but
they shouldn't be using it anyways. This gives the impression like auto
is some special display manager, when it's just lightdm and special pam
rules to allow root autoLogin. It was created for NixOS's testing
so I believe this is where it belongs.
