password rules

[raphi]

Hello all,

I've been lurking for quite a while on the pg lists but now I need some 
help or rather, want to start a discussion:


We can set a password for a role in PG but there is no way to force a 
user to change it, prevent reuse or to enforce some complexity on it. As 
I understand, that's by choice and when I ask about this, the usual 
answer is "that's not the job of a database, use LDAP for it".


To be fair, setting up LDAP is very easy in PG, just one line in 
hba.conf and all is done. But sadly, that's only where the problems 
begin. The difficult part is to embedd this setup into a company, 
especially a large one as I work for with over 1000 PG databases and at 
least that many roles. Someone needs to be able to manage the passwords 
in LDAP and this means someone has to decide who can change which 
passwords, which is usually where some sort of Identity and Access 
Management (IAM) comes into place.


We already have LDAP and IAM in place in our organization for many other 
things, but IAM identities are coupled to a real person, not a team. 
Which means only one person in the team would be able to set a new 
password and when that person leaves the team, IAM rights need to be 
revoked and given to a new person. Doable, but quite a pane in the 
behind, especially when that one person happens to be on holidays. The 
prefered way would be to couple the rights to a dev-team-specific IAM 
role, which is something I am trying to get the okay for from our 
security for the past two years but failed so far (they argue it's a 
PCI/DSS requirement).


What I wish for are two seamingly simple features in PG that would solve 
all our problems without LDAP:


- enforce some password complexity and prevent reuse

- expire a password immediately after creating and prompt the user to 
change it upon first login try. They can connect with the initial 
password but cannot login until they've set a new password.


Background is: our developers can manage their own databases for their 
applications via a self service we've build for them. They can configure 
which databases and roles they need, our self service deployes 
everything, generates a password and sends the info to the dev via 
email. They idea would be, that the dev will change the password 
immediately but we cannot enforce that the dev will change the password, 
ever. And we also can't prevent the dev from setting "1234" as a 
password. With LDAP we could do all this but as stated above, it's not 
easy to implement (our "dev" is usually a team). We've reached a point 
where we (the dba team) are seriously discussing setting up our own LDAP 
server(s) without IAM, solely driven by our self service. But it will be 
tricky to find a setup without being a single point of failure for that 
many databases and get the okay for the resources needed to run and 
manage it, when we already have an "official" LDAP server.


I know there are extensions which are half-way there, like credcheck, 
but they suffer from the same drawback as most extensions, maintained 
only by a very small team or single person who after some years no 
longer has much time for it. Which is why we don't use any extension 
outside the official source code at all.


Sorry for this rather long (first) email on this list but I feel like I 
had to explain our usecase and why LDAP is not always as simple as 
adding a line to hba.conf. I understand the sentiment why some argue 
that this should not be the job of the DB but on the other hand, the DB 
already allows setting a password in the first place, hence why should 
it not be able to enforce some rules?


Is there any chance PG will provide this natively or are there any 
technical limitations I am unaware of? Can I do something to help 
bringing these feature into PG? My C knowledge is very limited so I 
won't be able to provide a patch but I'd be more than happy to test it. 
Also, I'll be at the Swiss PGday this week in Rapperswil if someone 
wants to discuss this in person ;)


have fun,

raphi

Re: password rules

[raphi]

Am 25.06.2025 um 01:20 schrieb Greg Sabino Mullane:

On Mon, Jun 23, 2025 at 2:45 PM raphi  wrote:

As of now though we cannot use PG for any PCI/DSS certified
application
because we can't enforce either complexity nor regular password
changes,


You can, and many, many companies do, but you need a modern auth 
system like Kerberos. Even if we were to put something into Postgres 
today (and given the MFA and re-use requirements, it's near 
impossible), PCI DSS keeps evolving and getting stricter, so keeping 
up with it would get harder with each release.


Can I do something to help bringing these feature into PG? My C
knowledge is very limited so I won't be able to provide a patch
but I'd be more than happy to test it.


Your energy would be much better used in bringing Kerberos into your 
organization. :)


Well as said, we have LDAP and IAM widely in use for everything except 
database access. It's the IAM part that's making it difficult for us to 
implement it for PG application/user roles, this wouldn't change by 
using Kerberos instead of LDAP. I thought we'll get the exception from 
our security to use IAM roles instead of physical persons defined as the 
owner of the PG accounts but now they are against it. Main reason is 
because they are looking into a completely different solution with 
Vault, which would fix some other issues and make it more robust towards 
PCI, and they prefer a solution for everything rather than making 
another exception. But we are speaking about years here, 2027 earliest 
and they haven't even talked to us yet how this would work with PG, only 
other DB products.


have fun,
raphi

Re: password rules

[raphi]

Am 25.06.2025 um 13:55 schrieb Peter J. Holzer:

On 2025-06-23 16:35:35 +0200, raphi wrote:

To be fair, setting up LDAP is very easy in PG, just one line in hba.conf
and all is done. But sadly, that's only where the problems begin. The
difficult part is to embedd this setup into a company, especially a large
one as I work for with over 1000 PG databases and at least that many roles.
Someone needs to be able to manage the passwords in LDAP and this means
someone has to decide who can change which passwords, which is usually where
some sort of Identity and Access Management (IAM) comes into place.

We already have LDAP and IAM in place in our organization for many other
things, but IAM identities are coupled to a real person, not a team. Which
means only one person in the team would be able to set a new password and
when that person leaves the team, IAM rights need to be revoked and given to
a new person. Doable, but quite a pane in the behind, especially when that
one person happens to be on holidays.

I don't see why that should be the case. You could either grant
privileges to more than one person or - preferrably - to a role which is
then granted to the personal roles.

So for example you would authenticate as «raphi» and I as «hjp» but we
could both change to «foo_admin» or whatever. That would even have the
advantage that we leave an audit trail with our "real" identities.

That's not how the identiy principle works, at least not how it's 
implement in our company. A user in ldap has a direct relation to one 
digital entity, either a token from an application or certificate from a 
physical person (maybe some AD shenanigans also). We don't have digital 
entities for teams, that's what's missing. For it to work they 
(security) would need to allow to weaken this principle and as you said, 
allow everyone who has a certain role to manage the associated user in 
LDAP, like setting a new password. Technically possible and we have 
similar mechanisms in place for other access, but authentication is then 
made by key or certificate, ldap/iam is only used to control who can 
access what.


But "our" problem aside, I still don't quite understand the decision 
that this was never implemented. If password authentication is so bad, 
why allow it all then? And when it's allowed, why not provide some basic 
features to make it more secure? The lack of any password rules is in it 
self the reason why it is so dangerous to use passwords in PG. I'd argue 
that the use of passwords with complexity requirements and TTL settings 
over an encrypted connection, with firewall rules and proper hba.conf 
access lists, are quite safe. Maybe even safer than a central solution 
like LDAP or Kerberos which is a single point of entry for an attacker, 
be it by attacking the software itself or the backup of the data, 
potentially getting access to everything instead of "just" one hacked 
password. But now I'm definitely getting into "let's have a beer" 
territory... ;)


have fun
raphi

Re: password rules

[raphi]

Am 23.06.2025 um 17:05 schrieb Tom Lane:

raphi  writes:

We can set a password for a role in PG but there is no way to force a
user to change it, prevent reuse or to enforce some complexity on it. As
I understand, that's by choice and when I ask about this, the usual
answer is "that's not the job of a database, use LDAP for it".
...
Is there any chance PG will provide this natively or are there any
technical limitations I am unaware of?

If you don't like using an extension for it, you're
out of luck.  (The core developers have too much to do already, so
we are never going to be receptive to arguments like "I don't want
to use an extension".
I'd be open to use an extension for this if there'd be one that is still 
maintained. The seemingly most popular one, credcheck, has an issue open 
for over a year, the password history is not being replicated to the 
standby so we can not use it. The other one, passwordpolicy, hasn't been 
updated in 6 years.

Extension or not, there are serious objections to many aspects of
such a feature, namely that they can't be enforced without requiring
clients to send cleartext passwords to the server.  That in itself
is a security problem.  For that matter, the whole business of using
passwords rather than other ID technologies (SSL certificates,
Kerberos/GSS tickets, etc) is feeling pretty twentieth-century.
We only allow encrypted connections as (hopefully) most do and don't log 
any passwords but I see your point. As said, it's an ongoing battle 
between what DBAs need and what is possible in our environment. After my 
discussion today with our security officer, LDAP will probably never be 
the solution for us because of IAM (which is why I wrote here). He 
mentioned a project for next year where they want to look into a Vault 
solution. It's still password authentication but with complexity, TTL 
and "hidden" from users.


As of now though we cannot use PG for any PCI/DSS certified application 
because we can't enforce either complexity nor regular password changes, 
which is required in PCI - and they are fine with using passwords per 
se, but with constraints. We can with other DB products, which is a 
pitty, it disqualifies PG automatically from the discussion for certain 
applications even when PG would be the better fit. I would've thought 
that this alone would put password handling back on the todo list, 
providing PCI compliance out-of-the-box without the need of additional 
infrastructure would be something to brag about :D Because 20th or 21th 
century, password authentication will probably be used for a long time, 
especially when it's still allowed by PCI and other industry standards.


One last thing, any chance that "valid until" could get a flag where DBA 
can choose if the user will have a chance to set a new password when it 
expires instead of just locking the account? So when it expires, the 
user can still connect but not login, they can only set a new password, 
idealy with some mechanism preventing the user from setting the same 
password as before (compare the input with the current one, e.g. login 
in the background with the pass and when it succeeds, ask the user to 
give a different password or something like that).


have fun,
raphi

Re: password rules

[raphi]

Am 23.06.2025 um 22:39 schrieb Christoph Berg:

Re: raphi

Sorry for this rather long (first) email on this list but I feel like I had
to explain our usecase and why LDAP is not always as simple as adding a line
to hba.conf.

Did you give the "pam" method a try? T
Not really because it's a local solution. How do you change passwords or 
keep history on your standby nodes? Besides, the documentation says that 
postgres can't handle /etc/shadow because it runs unprivileged, only 
pam_ldap would work. Or am I missing something?


have fun,
raphi

Re: password rules

[raphi]

Am 25.06.2025 um 17:33 schrieb Peter J. Holzer:

On 2025-06-25 14:42:26 +0200, raphi wrote:
[snip]

That's not how the identiy principle works, at least not how it's implement
in our company. A user in ldap has a direct relation to one digital entity,
either a token from an application or certificate from a physical person
(maybe some AD shenanigans also). We don't have digital entities for teams,
that's what's missing. For it to work they (security) would need to allow to
weaken this principle and as you said, allow everyone who has a certain role
to manage the associated user in LDAP, like setting a new password.

That user shouldn't have a password, since nobody is authenticating as
that user. It also doesn't have to exist in LDAP. It's just a role in
the database.
hmm I don't follow, maybe I was doing it wrong? In my tests I configured 
LDAP as described in the documentation: 
https://www.postgresql.org/docs/current/auth-ldap.html


[quote]
Once the user has been found in this search, the server re-binds to the 
directory as this user, using the password specified by the client, to 
verify that the login is correct

[/quote]

And this worked as expected, when the user provided the password stored 
in LDAP, they could login and couldn't when given a wrong (or empty) 
password. Can you elaborate on what you mean?


[snip]

But do they? "Complexity" (scare quotes intentional) rules are easy to
circumvent and when people don't see the need for strong passwords, they
will do so. If they do see the need they will use strong passwords on
their own and the rules are somewhere between unnecessary and
counter-productive. Most guidelines also have stopped recommending
mandatory password rotations quite some time ago.

These features provide convenient boxes for auditors to tick off and
security for management who can claim that they did something.
Operational security? Not so much.

(just my personal opinion as someone who's been a sysadmin for over 20
years (although not recently))
Well, PCI still does. But checking auditors boxes is not the main reason 
I am looking for a solution (because we don't have any PCI applications 
on PG yet anyway) but our self service: An ansible playbook creates a 
role for someone and sends the password by email to the user who wanted 
the role created. This password ought to be temporary and should be 
changed upon first connect. Without any checks we can't neither ensure 
that the password will be changed nor that it won't be reused. We make 
it clear that this should happen and most devs probably do the sensible 
thing and set a new complex password but as you said, some people are 
just lazy and there's no feasable way for us to verify this.


have fun
raphi (who also was once in an almost forgotten lifetime a solaris admin 
for over 20 years ;))

Re: Simulate a PITR in postgresql 16

[raphi]

Am 30.06.2025 um 21:45 schrieb Ron Johnson:
Using PgBackRest might be more convenient, since it handles everything 
you need, is multithreaded, never removes too many wal files, 
compresses files if you want and also encrypts them if you want.


I agree, with pgBackRest it's basically: pgbackrest --stanza=demo 
--delta --type=time "--target=2025-05-05 15:37:03.157376+00" 
--target-action=promote restore


and you are done. It will also restore configure files and you can also 
selectively restore only one DB in the cluster if you want to speed up 
things. Works very well with S3 too and is very easy to integrate in an 
ansible playbook to have a generic way to do PITRs.


Check out the official user guide: https://pgbackrest.org/user-guide.html

have fun
raphi

Re: password rules

[raphi]

Am 26.06.2025 um 14:27 schrieb Peter J. Holzer:

On 2025-06-25 17:55:12 +0200, raphi wrote:

Am 25.06.2025 um 17:33 schrieb Peter J. Holzer:

On 2025-06-25 14:42:26 +0200, raphi wrote:

That's not how the identiy principle works, at least not how it's
implement in our company. A user in ldap has a direct relation to
one digital entity, either a token from an application or
certificate from a physical person (maybe some AD shenanigans
also). We don't have digital entities for teams, that's what's
missing. For it to work they (security) would need to allow to
weaken this principle and as you said, allow everyone who has a
certain role to manage the associated user in LDAP, like setting a
new password.

That user shouldn't have a password, since nobody is authenticating as
that user. It also doesn't have to exist in LDAP. It's just a role in
the database.

hmm I don't follow, maybe I was doing it wrong?

I'm thinking of something like this:

Roles assigned to people are in LDAP, and only they have passwords.
Application roles don't have to be in LDAP (maybe there are operational
reasons to have them there, but PostgreSQL doesn't need them) and don't
have passwords.
Thank you very much for the detailed test. It will be useful for other 
ideas I have but (I think) it does not solve our particular case. Maybe 
I wasn't clear enough and I'm sorry for that, but our problem lies in 
the way how applications connect. The passwords that devs are ordering 
via our self service is for the application that is connecting to the 
database, not for themselfs. It's the application's password that we 
want to ensure that it is complex and gets changed after we set an 
initial password for it. Because PG does not do it, we wanted to resolve 
this with LDAP but failed due to IAM.


But, I just returned from the once again phenomenal Swiss PGDays and I 
had the chance to talk to Laurenz and Dani and I can say, that I finally 
get it now. Laurenz explained very well how the whole authentication 
works and that the philosophy is that the postgres server should never 
know any passwords. I think that's what Tom tried to say but I failed to 
understand it correctly, I thought the issue is not having unencrypted 
passwords being sent over the network. So, why this also does not solve 
our problem, I am giving up on trying to use PG to enforce some password 
rules, I'm not even sure if credcheck is still a good idea. But the more 
I think about it the more I like switching to certificates, after all we 
already have mechanisms in place to automatically get new officially 
trusted (not selfsigned) certificates, it could be adoptable for PG 
connects too. I'm just not sure how and if all our applications can 
adopt this, but that's a "me" problem.


Anyways, thanks to everyone who helped me see the PG way, I won't bother 
anyone with this topic again ;)


have fun,
raphi

Re: password rules

[raphi]

Am 28.06.2025 um 15:59 schrieb Peter J. Holzer:

On 2025-06-27 19:00:36 +0200, raphi wrote:


It's the application's password that we want to ensure that it is
complex and gets changed after we set an initial password for it.

Why let a human change that at all? Couldn't you just create a suitable
random password at deployment time? (And then automatically every n
months if you want to rotate it.)

Because someone has to configure the password in the application, mostly 
within WLS or Tomcat and that's definitely not something that we DBA 
want to touch, that's the devs job. Which means we would have to provide 
some mechanism for the application to grab the password, say from a file 
or something, which has it's own pitfalls. Not to mention that we DBA 
usually don't want to know any application passwords. The only feasable 
way to implement this is with hashicorp Vault or something similar, then 
no one knows the password, neither DBA nor Dev and it would be 
guaranteed that it's complex. And application maintenance by a dev 
directly in the DB could then be made with personal logins via LDAP and 
switching to the application role as you so splendidly described ;) Same 
would be true for SSL certificates, only the application would need it 
and the devs could login via LDAP.


have fun
raphi