Обсуждение: enebling regular user to create new users ?

Zlatko Matić wrote:
> Hi. I know that superusers are allowed to do everything on the
> database, but I consider this as dangerous. I want to  have some user
> group with rights of creating new users and giving them some
> authorizations, but without such wide power as superusers have. So, I
> was thinking about two possible scenarios: a) to allow regular users
> to create new users b) to restrict superuser's permissions
>
> What is possible and what do you suggest ?

Neither is possible directly. (B) means they're not a superuser and (A)
means they are. You could create a function marked "SECURITY DEFINER" as
a super-user and have that function create users on behalf of regular
users though.

--
   Richard Huxton
   Archonet Ltd

Zlatko Matić wrote:

> I know that superusers are allowed to do everything on the database,
> but I consider this as dangerous. I want to  have some user group with
> rights of creating new users and giving them some authorizations, but
> without such wide power as superusers have. So,
> I was thinking about two possible scenarios:
> a) to allow regular users  to create new users
> b) to restrict superuser's permissions
>
> What is possible and what do you suggest ?

CREATE OR REPLACE FUNCTION create_user(name)
  RETURNS bool AS
'
DECLARE
  PWD VARCHAR;
  CMD VARCHAR;
BEGIN
  PWD := \'\'\'\' || get_random_string(8) || \'\'\'\';
  IF EXISTS(SELECT 1 FROM pg_user WHERE usename = $1) THEN
    RETURN FALSE;
  END IF;
  CMD := \'CREATE USER "\' || $1 || \'" WITH ENCRYPTED PASSWORD \' ||
PWD || \' IN GROUP gen_user\';
  EXECUTE CMD;
  RETURN TRUE;
END;
'
  LANGUAGE 'plpgsql' VOLATILE SECURITY DEFINER;
REVOKE ALL ON FUNCTION create_user(name) FROM public;
GRANT EXECUTE ON FUNCTION create_user(name) TO GROUP pseudo_dba;


CREATE OR REPLACE FUNCTION alter_group(name, bool, name)
  RETURNS bool AS
'
DECLARE
  l_group ALIAS FOR $1;
  l_create_user ALIAS FOR $2;
  l_username ALIAS FOR $3;
  CMD VARCHAR;
  MIN_SUPER_USER INTEGER := 1;
BEGIN
  IF (l_create_user NOTNULL)  THEN
    IF (l_create_user) THEN
      PERFORM create_user(l_username);
      CMD := \'ALTER GROUP \' || l_group || \' ADD USER "\' ||
l_username || \'"\';
      EXECUTE CMD;
    ELSIF (l_group = \'gen_user\') THEN
      PERFORM drop_user(l_username);
    ELSE
      CMD := \'ALTER GROUP \' || l_group || \' DROP USER "\' ||
l_username || \'"\';
      EXECUTE CMD;
    END IF;
    IF (SELECT COUNT(*) FROM group_members WHERE groname =
\'pseudo_dba\') < MIN_SUPER_USER THEN
      RAISE EXCEPTION \'At least % super user(s) must be defined in
order to create new user accounts.\', MIN_SUPER_USER;
    END IF;
  END IF;
  RETURN TRUE;
END;
'
  LANGUAGE 'plpgsql' VOLATILE SECURITY DEFINER;
REVOKE ALL ON FUNCTION alter_group(name, bool, name) FROM public;
GRANT EXECUTE ON FUNCTION alter_group(name, bool, name) TO GROUP pseudo_dba;

-- etc., etc., etc.,

Richard Huxton <dev@archonet.com> writes:
> Zlatko Mati� wrote:
>> I was thinking about two possible scenarios: a) to allow regular users
>> to create new users b) to restrict superuser's permissions
>>
>> What is possible and what do you suggest ?

> Neither is possible directly. (B) means they're not a superuser and (A)
> means they are.

There has been some talk of separating the power to create new users
from the power of being superuser (although presumably only a superuser
should be allowed to create new superusers).  If the planned pg_role
rewrite gets submitted before the 8.1 feature freeze, I might look at
adding that frammish into it.

            regards, tom lane

On Wed, 2005-06-15 at 12:50 -0400, Tom Lane wrote:
> I might look at
> adding that frammish into it

Frammish?

Tom Lane wrote:
> Richard Huxton <dev@archonet.com> writes:
>
>>Zlatko Matiæ wrote:
>>
>>>I was thinking about two possible scenarios: a) to allow regular users
>>>to create new users b) to restrict superuser's permissions
>>>
>>>What is possible and what do you suggest ?
>
>>Neither is possible directly. (B) means they're not a superuser and (A)
>>means they are.
>
> There has been some talk of separating the power to create new users
> from the power of being superuser (although presumably only a superuser
> should be allowed to create new superusers).  If the planned pg_role
> rewrite gets submitted before the 8.1 feature freeze, I might look at
> adding that frammish into it.

Did I see talk of per-database users too? That would be a sensible
dividing-line I suppose - you could have complete control of "your"
database and who can access it without interfering with anyone else.

--
   Richard Huxton
   Archonet Ltd

Per-database user, right, that's what I need...hope it will be included in
future releases...
Separating the power to create new users from the power of being superuser,
also. It is very important.
Greetings,

Zlatko

----- Original Message -----
From: "Richard Huxton" <dev@archonet.com>
To: "Tom Lane" <tgl@sss.pgh.pa.us>
Cc: "Zlatko Matić" <zlatko.matic1@sb.t-com.hr>;
<pgsql-general@postgresql.org>
Sent: Wednesday, June 15, 2005 9:35 PM
Subject: Re: [GENERAL] enebling regular user to create new users ?


Tom Lane wrote:
> Richard Huxton <dev@archonet.com> writes:
>
>>Zlatko Matiæ wrote:
>>
>>>I was thinking about two possible scenarios: a) to allow regular users
>>>to create new users b) to restrict superuser's permissions
>>>
>>>What is possible and what do you suggest ?
>
>>Neither is possible directly. (B) means they're not a superuser and (A)
>>means they are.
>
> There has been some talk of separating the power to create new users
> from the power of being superuser (although presumably only a superuser
> should be allowed to create new superusers).  If the planned pg_role
> rewrite gets submitted before the 8.1 feature freeze, I might look at
> adding that frammish into it.

Did I see talk of per-database users too? That would be a sensible
dividing-line I suppose - you could have complete control of "your"
database and who can access it without interfering with anyone else.

--
   Richard Huxton
   Archonet Ltd


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