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firebird-mirror/doc/sql.extensions/README.mapping.html
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<body lang="ru-RU" dir="ltr"><p lang="en-US" style="margin-bottom: 0cm">
<font size="4" style="font-size: 14pt">SQL Language Extension:
CREATE/ALTER/CREATE_OR_ALTER/DROP MAPPING</font></p>
<p style="margin-bottom: 0cm"><br/>
</p>
<p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">Implements
capability to control mapping of security objects to and between
databases.</font></p>
<p style="margin-bottom: 0cm"><br/>
</p>
<p style="margin-bottom: 0cm"><br/>
</p>
<p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">Author:</font></p>
<p style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt"><span lang="en-US">Alex
Peshkoff &lt;<a href="mailto:peshkoff@mail.ru">peshkoff@mail.ru</a>&gt;</span></font></p>
<p style="margin-bottom: 0cm"><br/>
</p>
<p style="margin-bottom: 0cm"><br/>
</p>
<p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">Preamble:</font></p>
<p style="margin-bottom: 0cm"><br/>
</p>
<p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">Firebird
3 supports multiple security databases. This is great feature, but it
raises some problems, missing in systems with single security
database. Clusters of databases, using same security database, are
efficiently separated and this is what we typically want to achieve
using different security databases. But in some cases we need
controlled limited interaction between such clusters. As an examples
can be provided EXECUTE STATEMENT ON EXTERNAL DATA SOURCE when some
data exchange between clusters is required and letting server-wide
SYSDBA access databases from other clusters using services. More or
less similar problems were already known in windows version of
firebird since v. 2.1 due to presence of trusted windows
authentication – we had 2 separate lists of users (in security
database and OS) and sometimes it was needed to make them be related.
For example it appears to be good idea to automatically assign to
windows users from some group appropriate firebird role.</font></p>
<p style="margin-bottom: 0cm"><br/>
</p>
<p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">Single
solution for all this problems is MAPPING login information, assigned
to user when it connected to firebird server, to internal security
objects in database – current_user and current_role. Mapping rule
contains 4 parts of information: </font>
</p>
<ul>
<li><p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">mapping
scope (is mapping local for current database or affects all
databases in cluster, including security database),</font></p>
<li><p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">mapping
name (mappings are named like all the other objects in database), </font>
</p>
<li><p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">from
what we map </font>
</p>
<li><p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">to
what we map.</font></p>
</ul>
<p style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">Here
it's necessary to mention that all versions of firebird had one
hardcoded global default rule – users authenticated in security
database are always mapped into any database one-to-one. This rule is
safe - if we have some security database it makes no use not to trust
itself. Therefore (and due to backward compatibility) this rule is
kept as is in firebird 3. What about mapping windows users to
current_user (which was enabled by default in 2.1 &amp; 2.5 when
trusted authentication enabled) in firebird 3 it must be done
explicitly. This is required for systems with multiple security
databases - not all of them need/use windows trusted authentication.</font></p>
<p style="margin-bottom: 0cm"><br/>
</p>
<p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">'From'
part of mapping has 4 items:</font></p>
<ul>
<li><p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">authentication
source (plugin name or result of mapping in other database or use of
serverwide authentication or any method),</font></p>
<li><p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">name
of database where authentication succeeded, </font>
</p>
<li><p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">name
from which mapping is performed,</font></p>
<li><p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">type
of that name (username, role, OS group – this depends upon plugin
which added that name during authentication).</font></p>
</ul>
<p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">Each
item may be ignored (any item is accepted) except type – it's
definitely bad idea to mix different types of security objects.</font></p>
<p style="margin-bottom: 0cm"><br/>
</p>
<p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">'To'
part has 2 items:</font></p>
<ul>
<li><p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">name
to which mapping is performed,</font></p>
<li><p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">type
of that name (only USER/ROLE are accepted here).</font></p>
</ul>
<p style="margin-bottom: 0cm"><br/>
</p>
<p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">Mappings
are defined using SQL (DDL) commands.</font></p>
<p style="margin-bottom: 0cm"><br/>
</p>
<p style="margin-bottom: 0cm"><br/>
</p>
<p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">Syntax:</font></p>
<p style="margin-bottom: 0cm"><br/>
</p>
<p lang="en-US" style="margin-left: 1.17cm; margin-bottom: 0cm; page-break-before: auto; page-break-after: auto">
<font size="4" style="font-size: 14pt">{CREATE | ALTER | CREATE OR
ALTER} [GLOBAL] MAPPING name</font></p>
<p lang="en-US" style="margin-left: 2.18cm; margin-bottom: 0cm; page-break-before: auto; page-break-after: auto">
<font size="4" style="font-size: 14pt">USING {PLUGIN name [IN
database] | </font>
</p>
<p lang="en-US" style="margin-left: 4.06cm; margin-bottom: 0cm; page-break-before: auto; page-break-after: auto">
<font size="4" style="font-size: 14pt">ANY PLUGIN [IN database |
SERVERWIDE] | </font>
</p>
<p lang="en-US" style="margin-left: 4.06cm; margin-bottom: 0cm"><font size="4" style="font-size: 14pt">MAPPING
[IN database] | </font>
</p>
<p lang="en-US" style="margin-left: 4.06cm; margin-bottom: 0cm"><font size="4" style="font-size: 14pt">'*'
[IN database]}</font></p>
<p lang="en-US" style="margin-left: 2.23cm; margin-bottom: 0cm; page-break-before: auto; page-break-after: auto">
<font size="4" style="font-size: 14pt">FROM {ANY type | type name}</font></p>
<p lang="en-US" style="margin-left: 2.23cm; margin-bottom: 0cm"><font size="4" style="font-size: 14pt">TO
{USER | ROLE} [name]</font></p>
<p style="margin-left: 1.17cm; margin-bottom: 0cm"><br/>
</p>
<p lang="en-US" style="margin-left: 1.17cm; margin-bottom: 0cm"><font size="4" style="font-size: 14pt">DROP
[GLOBAL] MAPPING name</font></p>
<p style="margin-bottom: 0cm"><br/>
</p>
<p style="margin-bottom: 0cm"><br/>
</p>
<p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">Description:</font></p>
<p style="margin-bottom: 0cm"><br/>
</p>
<p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">Each
mapping may be tagged as GLOBAL. Pay attention that global and local
maps with same name may exist and they are different objects!</font></p>
<p style="margin-bottom: 0cm"><br/>
</p>
<p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">Create,
alter and create or alter commands use same set of options. Name of
mapping is used to identify it in former DDL commands. USING clause
has a most complicated set of options. One can provide explicit
plugin name, making it work only for given plugin, or make it use any
plugin (but not a result of previous mappings), or make it work only
with server-wide plugins, or make it work only with previous mapping
results, or let it use any method using asterisk. In almost all cases
(except server-wide authentication which is not related with
databases) one can also provide name of database in which name from
which mapping is performed was “born”. FROM clause must set
required parameter – type of name from which mapping is done. When
mapping names from plugins type is defined by plugin, when previous
mapping results - type can be only user or role. One can provide
explicit name which will be taken into an account by this mapping or
use ANY keyword to work with any name of given type. In TO clause
USER or ROLE (to what mapping is done) must be specified, name is
optional - when it is not provided original name (from what mapping
is done) is used.</font></p>
<p style="margin-bottom: 0cm"><br/>
</p>
<p style="margin-bottom: 0cm"><br/>
</p>
<p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">Samples:</font></p>
<p style="margin-bottom: 0cm"><br/>
</p>
<p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">All
sample are provided for CREATE command, use of ALTER is exactly the
same, use of DROP is obvious.</font></p>
<p style="margin-bottom: 0cm"><br/>
</p>
<p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">Enable
use of windows trusted authentication in all databases that use
current security database:</font></p>
<p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">CREATE
GLOBAL MAPPING TRUSTED_AUTH USING PLUGIN WIN_SSPI FROM ANY USER TO
USER;</font></p>
<p style="margin-bottom: 0cm"><br/>
</p>
<p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">Enable
SYSDBA-like access for windows admins in current database:</font></p>
<p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">CREATE
MAPPING WIN_ADMINS USING PLUGIN WIN_SSPI FROM Predefined_Group
DOMAIN_ANY_RID_ADMINS TO ROLE RDB$ADMIN;</font></p>
<p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">(there
is no group DOMAIN_ANY_RID_ADMINS in windows, but such name is added
by win_sspi plugin to provide exact backwards compatibility)</font></p>
<p style="margin-bottom: 0cm"><br/>
</p>
<p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">Enable
particular user from other database access current database with
other name:</font></p>
<p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">CREATE
MAPPING FROM_RT USING PLUGIN SRP IN &quot;rt&quot; FROM USER U1 TO
USER U2;</font></p>
<p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">(providing
database names/aliases in double quotes is important for operating
systems that have case-sensitive file names)</font></p>
<p style="margin-bottom: 0cm"><br/>
</p>
<p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">Enable
server's SYSDBA (from main security database) access current database
(assuming it has non-default security database):</font></p>
<p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">CREATE
MAPPING DEF_SYSDBA USING PLUGIN SRP IN &quot;security.db&quot; FROM
USER SYSDBA TO USER;</font></p>
<p style="margin-bottom: 0cm"><br/>
</p>
<p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">Force
people who logged in using legacy authentication plugin have not too
much rights:</font></p>
<p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">CREATE
MAPPING LEGACY_2_GUEST USING PLUGIN legacy_auth FROM ANY USER TO USER
GUEST;</font></p>
<p style="margin-bottom: 0cm"><br/>
</p>
<p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">Map
windows group to trusted firebird role:</font></p>
<p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">CREATE
MAPPING WINGROUP1 USING PLUGIN WIN_SSPI FROM GROUP GROUP_NAME TO ROLE
ROLE_NAME;</font></p>
<p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">Here
we expect that some windows users may belong to group GROUP_NAME. If
needed name of the group may be given in long form, i.e.
DOMAIN\GROUP.</font></p>
<p style="margin-bottom: 0cm"><br/>
</p>
<p style="margin-bottom: 0cm"><br/>
</p>
<p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">Notice:</font></p>
<p style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt"><span lang="en-US">-
Global mapping works best if firebird 3 or higher version database is
used as security database. If you plan to use other database as
security one (using for example your own provider) please create in
it table RDB$AUTH_MAPPING with structure repeating one in firebird 3
database, public read access and SYSDBA-only write access.</span></font></p>
<p style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt"><span lang="en-US">-
</span></font><font size="4" style="font-size: 14pt"><span lang="en-US">Mappings
work only with information, coming from authentication plugins or
previously done mapping. Information present in DPB (particular SQL
role name) is not affected by mappings and can not be changed using
them.</span></font></p>
<p style="margin-bottom: 0cm"><br/>
</p>
<p style="margin-bottom: 0cm"><br/>
</p>
<p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">Tip:</font></p>
<p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">It’s
relatively easy to accidentally make a database remotely inaccessible
using CREATE MAPPING statement. For example: </font>
</p>
<p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">CREATE
MAPPING BREAK_DB_1 USING * FROM ANY USER TO ROLE ROLE1;</font></p>
<p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">CREATE
MAPPING BREAK_DB_2 USING * FROM ANY USER TO ROLE ROLE2;</font></p>
<p lang="en-US" style="margin-bottom: 0cm"><font size="4" style="font-size: 14pt">This
will disallow any user (including SYSDBA) to connect. Luckily
mappings are not processed when database is used in embedded mode,
i.e. in such a case one should attach to database using embedded
access and fix bad mappings.</font></p>
<p style="margin-bottom: 0cm"><br/>
</p>
<p style="margin-bottom: 0cm"><br/>
</p>
</body>
</html>
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