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Revamp documentation for predefined roles.

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Presently, the page for predefined roles contains a table with
brief descriptions of what each role allows.  Below the table,
there is a separate section with more detailed information about
some of the roles.  As the set of predefined roles has grown over
the years, this page has (IMHO) become less readable.

This commit attempts to improve the predefined roles documentation
by abandoning the table in favor of listing each role with its own
complete description, similar to how we document GUCs.  Besides
merging the information that was split between the table and the
section below it, this commit also alphabetizes the roles.  The
alphabetization is imperfect because some of the roles are grouped
(e.g., pg_read_all_data and pg_write_all_data), and we order such
groups by the first role mentioned, but that seemed like a better
choice than breaking the groups apart.  Finally, this commit makes
some stylistic adjustments to the text.

Reviewed-by: David G. Johnston, Robert Haas
Discussion: https://postgr.es/m/ZmtM-4-eRtq8DRf6%40nathan
This commit is contained in:
Nathan Bossart 2024-07-10 16:35:25 -05:00
parent 0dcf753bd8
commit cc2236854e
5 changed files with 191 additions and 162 deletions
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2
doc/src/sgml/config.sgml
View File

@ -731,7 +731,7 @@ include_dir 'conf.d'
<para>
Determines the number of connection <quote>slots</quote> that are
reserved for connections by roles with privileges of the
<link linkend="predefined-roles-table"><literal>pg_use_reserved_connections</literal></link>
<xref linkend="predefined-role-pg-use-reserved-connections"/>
role. Whenever the number of free connection slots is greater than
<xref linkend="guc-superuser-reserved-connections"/> but less than or
equal to the sum of <varname>superuser_reserved_connections</varname>

4
doc/src/sgml/monitoring.sgml
View File

@ -286,8 +286,8 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser
other sessions, many columns will be null. Note, however, that the
existence of a session and its general properties such as its sessions user
and database are visible to all users. Superusers and roles with privileges of
built-in role <literal>pg_read_all_stats</literal> (see also <xref
linkend="predefined-roles"/>) can see all the information about all sessions.
built-in role <link linkend="predefined-role-pg-monitor"><literal>pg_read_all_stats</literal></link>
can see all the information about all sessions.
</para>
<table id="monitoring-stats-dynamic-views-table">

2
doc/src/sgml/ref/checkpoint.sgml
View File

@ -53,7 +53,7 @@ CHECKPOINT
<para>
Only superusers or users with the privileges of
the <link linkend="predefined-roles-table"><literal>pg_checkpoint</literal></link>
the <xref linkend="predefined-role-pg-checkpoint"/>
role can call <command>CHECKPOINT</command>.
</para>
</refsect1>

2
doc/src/sgml/ref/reindex.sgml
View File

@ -305,7 +305,7 @@ REINDEX [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] { DA
partitioned table, such commands skip the privilege checks when processing
the individual partitions. Reindexing a schema or database requires being the
owner of that schema or database or having privileges of the
<link linkend="predefined-roles-table"><literal>pg_maintain</literal></link>
<xref linkend="predefined-role-pg-maintain"/>
role. Note specifically that it's thus
possible for non-superusers to rebuild indexes of tables owned by
other users. However, as a special exception,

343
doc/src/sgml/user-manag.sgml
View File

@ -590,106 +590,73 @@ DROP ROLE doomed_role;
and information. Administrators (including roles that have the
<literal>CREATEROLE</literal> privilege) can <command>GRANT</command> these
roles to users and/or other roles in their environment, providing those
users with access to the specified capabilities and information.
users with access to the specified capabilities and information. For
example:
<programlisting>
GRANT pg_signal_backend TO admin_user;
</programlisting>
</para>
<warning>
<para>
Care should be taken when granting these roles to ensure they are only used
where needed and with the understanding that these roles grant access to
privileged information.
</para>
</warning>
<para>
The predefined roles are described in <xref linkend="predefined-roles-table"/>.
The predefined roles are described below.
Note that the specific permissions for each of the roles may change in
the future as additional capabilities are added. Administrators
should monitor the release notes for changes.
</para>
<table tocentry="1" id="predefined-roles-table">
<title>Predefined Roles</title>
<tgroup cols="2">
<colspec colname="col1" colwidth="1*"/>
<colspec colname="col2" colwidth="2*"/>
<thead>
<row>
<entry>Role</entry>
<entry>Allowed Access</entry>
</row>
</thead>
<tbody>
<row>
<entry>pg_read_all_data</entry>
<entry>Read all data (tables, views, sequences), as if having
<command>SELECT</command> rights on those objects, and USAGE rights on
all schemas, even without having it explicitly. This role does not have
the role attribute <literal>BYPASSRLS</literal> set. If RLS is being
used, an administrator may wish to set <literal>BYPASSRLS</literal> on
roles which this role is GRANTed to.</entry>
</row>
<row>
<entry>pg_write_all_data</entry>
<entry>Write all data (tables, views, sequences), as if having
<command>INSERT</command>, <command>UPDATE</command>, and
<command>DELETE</command> rights on those objects, and USAGE rights on
all schemas, even without having it explicitly. This role does not have
the role attribute <literal>BYPASSRLS</literal> set. If RLS is being
used, an administrator may wish to set <literal>BYPASSRLS</literal> on
roles which this role is GRANTed to.</entry>
</row>
<row>
<entry>pg_read_all_settings</entry>
<entry>Read all configuration variables, even those normally visible only to
superusers.</entry>
</row>
<row>
<entry>pg_read_all_stats</entry>
<entry>Read all pg_stat_* views and use various statistics related extensions,
even those normally visible only to superusers.</entry>
</row>
<row>
<entry>pg_stat_scan_tables</entry>
<entry>Execute monitoring functions that may take <literal>ACCESS SHARE</literal> locks on tables,
potentially for a long time.</entry>
</row>
<row>
<entry>pg_monitor</entry>
<entry>Read/execute various monitoring views and functions.
This role is a member of <literal>pg_read_all_settings</literal>,
<literal>pg_read_all_stats</literal> and
<literal>pg_stat_scan_tables</literal>.</entry>
</row>
<row>
<entry>pg_database_owner</entry>
<entry>None. Membership consists, implicitly, of the current database owner.</entry>
</row>
<row>
<entry>pg_signal_backend</entry>
<entry>Signal another backend to cancel a query or terminate its session.</entry>
</row>
<row>
<entry>pg_signal_autovacuum_worker</entry>
<entry>Signal an autovacuum worker to cancel the current table's vacuum
or terminate its session.</entry>
</row>
<row>
<entry>pg_read_server_files</entry>
<entry>Allow reading files from any location the database can access on the server with COPY and
other file-access functions.</entry>
</row>
<row>
<entry>pg_write_server_files</entry>
<entry>Allow writing to files in any location the database can access on the server with COPY and
other file-access functions.</entry>
</row>
<row>
<entry>pg_execute_server_program</entry>
<entry>Allow executing programs on the database server as the user the database runs as with
COPY and other functions which allow executing a server-side program.</entry>
</row>
<row>
<entry>pg_checkpoint</entry>
<entry>Allow executing
the <link linkend="sql-checkpoint"><command>CHECKPOINT</command></link>
command.</entry>
</row>
<row>
<entry>pg_maintain</entry>
<entry>Allow executing
<variablelist>
<varlistentry id="predefined-role-pg-checkpoint" xreflabel="pg_checkpoint">
<term><varname>pg_checkpoint</varname></term>
<listitem>
<para>
<literal>pg_checkpoint</literal> allows executing the
<link linkend="sql-checkpoint"><command>CHECKPOINT</command></link> command.
</para>
</listitem>
</varlistentry>
<varlistentry id="predefined-role-pg-create-subscription" xreflabel="pg_create_subscription">
<term><varname>pg_create_subscription</varname></term>
<listitem>
<para>
<literal>pg_create_subscription</literal> allows users with
<literal>CREATE</literal> permission on the database to issue
<link linkend="sql-createsubscription"><command>CREATE SUBSCRIPTION</command></link>.
</para>
</listitem>
</varlistentry>
<varlistentry id="predefined-role-pg-database-owner" xreflabel="pg_database_owner">
<term><varname>pg_database_owner</varname></term>
<listitem>
<para>
<literal>pg_database_owner</literal> always has exactly one implicit
member: the current database owner. It cannot be granted membership in
any role, and no role can be granted membership in
<literal>pg_database_owner</literal>. However, like any other role, it
can own objects and receive grants of access privileges. Consequently,
once <literal>pg_database_owner</literal> has rights within a template
database, each owner of a database instantiated from that template will
possess those rights. Initially, this role owns the
<literal>public</literal> schema, so each database owner governs local
use of that schema.
</para>
</listitem>
</varlistentry>
<varlistentry id="predefined-role-pg-maintain" xreflabel="pg_maintain">
<term><varname>pg_maintain</varname></term>
<listitem>
<para>
<literal>pg_maintain</literal> allows executing
<link linkend="sql-vacuum"><command>VACUUM</command></link>,
<link linkend="sql-analyze"><command>ANALYZE</command></link>,
<link linkend="sql-cluster"><command>CLUSTER</command></link>,
@ -697,76 +664,138 @@ DROP ROLE doomed_role;
<link linkend="sql-reindex"><command>REINDEX</command></link>,
and <link linkend="sql-lock"><command>LOCK TABLE</command></link> on all
relations, as if having <literal>MAINTAIN</literal> rights on those
objects, even without having it explicitly.</entry>
</row>
<row>
<entry>pg_use_reserved_connections</entry>
<entry>Allow use of connection slots reserved via
<xref linkend="guc-reserved-connections"/>.</entry>
</row>
<row>
<entry>pg_create_subscription</entry>
<entry>Allow users with <literal>CREATE</literal> permission on the
database to issue
<link linkend="sql-createsubscription"><command>CREATE SUBSCRIPTION</command></link>.</entry>
</row>
</tbody>
</tgroup>
</table>
objects.
</para>
</listitem>
</varlistentry>
<para>
The <literal>pg_monitor</literal>, <literal>pg_read_all_settings</literal>,
<literal>pg_read_all_stats</literal> and <literal>pg_stat_scan_tables</literal>
roles are intended to allow administrators to easily configure a role for the
purpose of monitoring the database server. They grant a set of common privileges
allowing the role to read various useful configuration settings, statistics and
other system information normally restricted to superusers.
</para>
<varlistentry id="predefined-role-pg-monitor" xreflabel="pg_monitor">
<term><varname>pg_monitor</varname></term>
<term><varname>pg_read_all_settings</varname></term>
<term><varname>pg_read_all_stats</varname></term>
<term><varname>pg_stat_scan_tables</varname></term>
<listitem>
<para>
These roles are intended to allow administrators to easily configure a
role for the purpose of monitoring the database server. They grant a
set of common privileges allowing the role to read various useful
configuration settings, statistics, and other system information
normally restricted to superusers.
</para>
<para>
<literal>pg_monitor</literal> allows reading/executing various
monitoring views and functions. This role is a member of
<literal>pg_read_all_settings</literal>,
<literal>pg_read_all_stats</literal> and
<literal>pg_stat_scan_tables</literal>.
</para>
<para>
<literal>pg_read_all_settings</literal> allows reading all configuration
variables, even those normally visible only to superusers.
</para>
<para>
<literal>pg_read_all_stats</literal> allows reading all pg_stat_* views
and use various statistics related extensions, even those normally
visible only to superusers.
</para>
<para>
<literal>pg_stat_scan_tables</literal> allows executing monitoring
functions that may take <literal>ACCESS SHARE</literal> locks on tables,
potentially for a long time (e.g., <function>pgrowlocks(text)</function>
in the <xref linkend="pgrowlocks"/> extension).
</para>
</listitem>
</varlistentry>
<para>
The <literal>pg_database_owner</literal> role has one implicit,
situation-dependent member, namely the owner of the current database. Like
any role, it can own objects or receive grants of access privileges.
Consequently, once <literal>pg_database_owner</literal> has rights within a
template database, each owner of a database instantiated from that template
will exercise those rights. <literal>pg_database_owner</literal> cannot be
a member of any role, and it cannot have non-implicit members. Initially,
this role owns the <literal>public</literal> schema, so each database owner
governs local use of the schema.
</para>
<varlistentry id="predefined-role-pg-read-all-data" xreflabel="pg_read_all_data">
<term><varname>pg_read_all_data</varname></term>
<term><varname>pg_write_all_data</varname></term>
<listitem>
<para>
<literal>pg_read_all_data</literal> allows reading all data (tables,
views, sequences), as if having <command>SELECT</command> rights on
those objects and <literal>USAGE</literal> rights on all schemas. This
role does not bypass row-level security (RLS) policies. If RLS is being
used, an administrator may wish to set <literal>BYPASSRLS</literal> on
roles which this role is granted to.
</para>
<para>
<literal>pg_write_all_data</literal> allows writing all data (tables,
views, sequences), as if having <command>INSERT</command>,
<command>UPDATE</command>, and <command>DELETE</command> rights on those
objects and <literal>USAGE</literal> rights on all schemas. This role
does not bypass row-level security (RLS) policies. If RLS is being
used, an administrator may wish to set <literal>BYPASSRLS</literal> on
roles which this role is granted to.
</para>
</listitem>
</varlistentry>
<para>
The <literal>pg_signal_backend</literal> role is intended to allow
administrators to enable trusted, but non-superuser, roles to send signals
to other backends. Currently this role enables sending of signals for
canceling a query on another backend or terminating its session. A user
granted this role cannot however send signals to a backend owned by a
superuser. See <xref linkend="functions-admin-signal"/>.
</para>
<varlistentry id="predefined-role-pg-read-server-files" xreflabel="pg_read_server_files">
<term><varname>pg_read_server_files</varname></term>
<term><varname>pg_write_server_files</varname></term>
<term><varname>pg_execute_server_program</varname></term>
<listitem>
<para>
These roles are intended to allow administrators to have trusted, but
non-superuser, roles which are able to access files and run programs on
the database server as the user the database runs as. They bypass all
database-level permission checks when accessing files directly and they
could be used to gain superuser-level access. Therefore, great care
should be taken when granting these roles to users.
</para>
<para>
<literal>pg_read_server_files</literal> allows reading files from any
location the database can access on the server using
<command>COPY</command> and other file-access functions.
</para>
<para>
<literal>pg_write_server_files</literal> allows writing to files in any
location the database can access on the server using
<command>COPY</command> and other file-access functions.
</para>
<para>
<literal>pg_execute_server_program</literal> allows executing programs
on the database server as the user the database runs as using
<command>COPY</command> and other functions which allow executing a
server-side program.
</para>
</listitem>
</varlistentry>
<para>
The <literal>pg_read_server_files</literal>, <literal>pg_write_server_files</literal> and
<literal>pg_execute_server_program</literal> roles are intended to allow administrators to have
trusted, but non-superuser, roles which are able to access files and run programs on the
database server as the user the database runs as. As these roles are able to access any file on
the server file system, they bypass all database-level permission checks when accessing files
directly and they could be used to gain superuser-level access, therefore
great care should be taken when granting these roles to users.
</para>
<varlistentry id="predefined-role-pg-signal-autovacuum-worker" xreflabel="pg_signal_autovacuum_worker">
<term><varname>pg_signal_autovacuum_worker</varname></term>
<listitem>
<para>
<literal>pg_signal_autovacuum_worker</literal> allows signaling
autovacuum workers to cancel the current table's vacuum or terminate its
session. See <xref linkend="functions-admin-signal"/>.
</para>
</listitem>
</varlistentry>
<para>
Care should be taken when granting these roles to ensure they are only used where
needed and with the understanding that these roles grant access to privileged
information.
</para>
<varlistentry id="predefined-role-pg-signal-backend" xreflabel="pg_signal_backend">
<term><varname>pg_signal_backend</varname></term>
<listitem>
<para>
<literal>pg_signal_backend</literal> allows signaling another backend to
cancel a query or terminate its session. Note that this role does not
permit signaling backends owned by a superuser. See
<xref linkend="functions-admin-signal"/>.
</para>
</listitem>
</varlistentry>
<para>
Administrators can grant access to these roles to users using the
<link linkend="sql-grant"><command>GRANT</command></link> command, for example:
<programlisting>
GRANT pg_signal_backend TO admin_user;
</programlisting>
<varlistentry id="predefined-role-pg-use-reserved-connections" xreflabel="pg_use_reserved_connections">
<term><varname>pg_use_reserved_connections</varname></term>
<listitem>
<para>
<literal>pg_use_reserved_connections</literal> allows use of connection
slots reserved via <xref linkend="guc-reserved-connections"/>.
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
</sect1>