We'd like to use it for FIDO2 tokens too, and the concept is entirely
generic, hence let's just reuse the field, but rename it. Read the old
name for compatibility, and treat the old name and the new name as
identical for most purposes.
We make this entirely independent of the regular discard field, i.e. the
one that controls discard behaviour when the home directory is online.
Not all combinations make a ridiculous amount of sense, but most do.
Specifically:
online-discard = yes, offline-discard = yes
→ Discard when activating explicitly, and during runtime using
the "discard" mount option, and discard explicitly when logging
out again.
online-discard = no, offline-discard = yes
→ The new default: when logging in allocate the full backing
store, and use no discard while active. When loging out discard
everything. This provides nice behaviour: we take minimal storage
when offline but provide allocation guarantees while online.
online-discard = no, offline-discard = no
→ Never, ever discard, always operate with fully allocated
backing store. The extra safe mode.
This reworks the user validation infrastructure. There are now two
modes. In regular mode we are strict and test against a strict set of
valid chars. And in "relaxed" mode we just filter out some really
obvious, dangerous stuff. i.e. strict is whitelisting what is OK, but
"relaxed" is blacklisting what is really not OK.
The idea is that we use strict mode whenver we allocate a new user
(i.e. in sysusers.d or homed), while "relaxed" mode is when we process
users registered elsewhere, (i.e. userdb, logind, …)
The requirements on user name validity vary wildly. SSSD thinks its fine
to embedd "@" for example, while the suggested NAME_REGEX field on
Debian does not even allow uppercase chars…
This effectively liberaralizes a lot what we expect from usernames.
The code that warns about questionnable user names is now optional and
only used at places such as unit file parsing, so that it doesn't show
up on every userdb query, but only when processing configuration files
that know better.
Fixes: #15149#15090
This prevents an error in pam_systemd when logging in.
sshd[2623165]: pam_unix(sshd:session): session opened for user tony.stark(uid=10001) by (uid=0)
sshd[2623165]: pam_systemd(sshd:session): Failed to get user record: Invalid argument
Bug: https://bugs.gentoo.org/708824
Lennart Poettering