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Shrink the pg_hba.conf and pg_ident.conf default files and move most of the

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inline documentation to the main docs.
This commit is contained in:
Peter Eisentraut
2002-09-14 18:35:46 +00:00
parent d73f8137d2
commit 49c86099f3
3 changed files with 295 additions and 423 deletions
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357
doc/src/sgml/client-auth.sgml
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@ -1,5 +1,5 @@
<!--
$Header: /cvsroot/pgsql/doc/src/sgml/client-auth.sgml,v 1.36 2002/08/16 04:48:16 momjian Exp $
$Header: /cvsroot/pgsql/doc/src/sgml/client-auth.sgml,v 1.37 2002/09/14 18:35:46 petere Exp $
-->
<chapter id="client-authentication">
@ -45,10 +45,10 @@ $Header: /cvsroot/pgsql/doc/src/sgml/client-auth.sgml,v 1.36 2002/08/16 04:48:16
database user names and OS user names.
</para>
<sect1 id="pg-hba-conf">
<sect1 id="auth-pg-hba-conf">
<title>The <filename>pg_hba.conf</filename> file</title>
<indexterm zone="pg-hba-conf">
<indexterm zone="auth-pg-hba-conf">
<primary>pg_hba.conf</primary>
</indexterm>
@ -85,9 +85,9 @@ $Header: /cvsroot/pgsql/doc/src/sgml/client-auth.sgml,v 1.36 2002/08/16 04:48:16
<para>
A record may have one of the three formats
<synopsis>
local <replaceable>database</replaceable> <replaceable>user</replaceable> <replaceable>authentication-method</replaceable> [ <replaceable>authentication-option</replaceable> ]
host <replaceable>database</replaceable> <replaceable>user</replaceable> <replaceable>IP-address</replaceable> <replaceable>IP-mask</replaceable> <replaceable>authentication-method</replaceable>
hostssl <replaceable>database</replaceable> <replaceable>user</replaceable> <replaceable>IP-address</replaceable> <replaceable>IP-mask</replaceable> <replaceable>authentication-method</replaceable>
local <replaceable>database</replaceable> <replaceable>user</replaceable> <replaceable>authentication-method</replaceable> <optional><replaceable>authentication-option</replaceable></optional>
host <replaceable>database</replaceable> <replaceable>user</replaceable> <replaceable>IP-address</replaceable> <replaceable>IP-mask</replaceable> <replaceable>authentication-method</replaceable> <optional><replaceable>authentication-option</replaceable></optional>
hostssl <replaceable>database</replaceable> <replaceable>user</replaceable> <replaceable>IP-address</replaceable> <replaceable>IP-mask</replaceable> <replaceable>authentication-method</replaceable> <optional><replaceable>authentication-option</replaceable></optional>
</synopsis>
The meaning of the fields is as follows:
@ -96,8 +96,9 @@ hostssl <replaceable>database</replaceable> <replaceable>user</replaceable> <rep
<term><literal>local</literal></term>
<listitem>
<para>
This record applies to connection attempts using Unix domain
sockets.
This record matches connection attempts using Unix domain
sockets. Without a record of this type, Unix-domain socket
connections are disallowed
</para>
</listitem>
</varlistentry>
@ -106,7 +107,7 @@ hostssl <replaceable>database</replaceable> <replaceable>user</replaceable> <rep
<term><literal>host</literal></term>
<listitem>
<para>
This record applied to connection attempts using TCP/IP networks.
This record matches connection attempts using TCP/IP networks.
Note that TCP/IP connections are disabled unless the server is
started with the <option>-i</option> option or the
<literal>tcpip_socket</> <filename>postgresql.conf</>
@ -119,13 +120,18 @@ hostssl <replaceable>database</replaceable> <replaceable>user</replaceable> <rep
<term><literal>hostssl</literal></term>
<listitem>
<para>
This record applies to connection attempts using SSL over
TCP/IP. To make use of this option the server must be
built with SSL support enabled. Furthermore, SSL must be
enabled with the <option>-l</> option or equivalent configuration
setting when the server is started. (Note: <literal>host</literal>
records will match either SSL or non-SSL connection attempts, but
<literal>hostssl</literal> records require SSL connections.)
This record matches connection attempts using SSL over TCP/IP.
<literal>host</literal> records will match either SSL or
non-SSL connection attempts, but <literal>hostssl</literal>
records require SSL connections.
</para>
<para>
To be able make use of this option the server must be built
with SSL support enabled. Furthermore, SSL must be enabled by
enabling the option <literal>ssl</literal> in
<filename>postgresql.conf</filename> (see <xref
linkend="runtime-config">).
</para>
</listitem>
</varlistentry>
@ -134,18 +140,18 @@ hostssl <replaceable>database</replaceable> <replaceable>user</replaceable> <rep
<term><replaceable>database</replaceable></term>
<listitem>
<para>
Specifies the database for this record. The value
<literal>all</literal> specifies that it applies to all
databases, while the value <literal>sameuser</> identifies the
database with the same name as the connecting user. The value
<literal>samegroup</> identifies a group with the same name as
the database name. Only members of this group can connect to the
database. Otherwise, this is the name of a specific
<productname>PostgreSQL</productname> database. Multiple database
names can be supplied by separating them with commas. A file
containing database names can be specified by preceding the file
name with <literal>@</>. The file must be in the same directory
as <filename>pg_hba.conf</>.
Specifies which databases this record matches. The value
<literal>all</literal> specifies that it matches all databases.
The value <literal>sameuser</> specifies that the record
matches if the requested database has the same name as the
requested user. The value <literal>samegroup</> specifies that
the requested user must a member of the group with the same
name as the requested database. Otherwise, this is the name of
a specific <productname>PostgreSQL</productname> database.
Multiple database names can be supplied by separating them with
commas. A file containing database names can be specified by
preceding the file name with <literal>@</>. The file must be in
the same directory as <filename>pg_hba.conf</>.
</para>
</listitem>
</varlistentry>
@ -154,41 +160,48 @@ hostssl <replaceable>database</replaceable> <replaceable>user</replaceable> <rep
<term><replaceable>user</replaceable></term>
<listitem>
<para>
Specifies the user for this record. The value
<literal>all</literal> specifies that it applies to all users.
Specifies which PostgreSQL users this record matches. The value
<literal>all</literal> specifies that it matches all users.
Otherwise, this is the name of a specific
<productname>PostgreSQL</productname> user. Multiple user names
can be supplied by separating them with commas. Group names can
be specified by preceding the group name with <literal>+</>. A
file containing user names can be specified by preceding the file
name with <literal>@</>. The file must be in the same directory
as <filename>pg_hba.conf</>.
file containing user names can be specified by preceding the
file name with <literal>@</>. The file must be in the same
directory as <filename>pg_hba.conf</>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><replaceable>IP address</replaceable></term>
<term><replaceable>IP mask</replaceable></term>
<term><replaceable>IP-address</replaceable></term>
<term><replaceable>IP-mask</replaceable></term>
<listitem>
<para>
These two fields specify the client machine IP addresses
(<literal>host</literal> or <literal>hostssl</literal>) for this
record. (Of course IP addresses can be spoofed but this
consideration is beyond the scope of
<productname>PostgreSQL</productname>.) The precise logic is that
These two fields contain IP address/mask values in standard
dotted decimal notation. (IP addresses can only be specified
numerically, not as domain or host names.) Taken together they
specify the client machine IP addresses that this record
matches. The precise logic is that
<blockquote>
<informalfigure>
<programlisting>(<replaceable>actual-IP-address</replaceable> xor <replaceable>IP-address-field</replaceable>) and <replaceable>IP-mask-field</replaceable></programlisting>
</informalfigure>
</blockquote>
must be zero for the record to match.
must be zero for the record to match. (Of course IP addresses
can be spoofed but this consideration is beyond the scope of
<productname>PostgreSQL</productname>.)
</para>
<para>
These fields only apply to <literal>host</literal> and
<literal>hostssl</literal> records.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><replaceable>authentication method</replaceable></term>
<term><replaceable>authentication-method</replaceable></term>
<listitem>
<para>
Specifies the authentication method to use when connecting via
@ -204,7 +217,8 @@ hostssl <replaceable>database</replaceable> <replaceable>user</replaceable> <rep
allows anyone that can connect to the
<productname>PostgreSQL</productname> database to login as
any <productname>PostgreSQL</productname> user they like,
without the need for a password.
without the need for a password. See <xref
linkend="auth-trust"> for details.
</para>
</listitem>
</varlistentry>
@ -226,6 +240,7 @@ hostssl <replaceable>database</replaceable> <replaceable>user</replaceable> <rep
Requires the client to supply an MD5 encrypted password for
authentication. This is the only method that allows encrypted
passwords to be stored in <structname>pg_shadow</structname>.
See <xref linkend="auth-password"> for details.
</para>
</listitem>
</varlistentry>
@ -237,6 +252,7 @@ hostssl <replaceable>database</replaceable> <replaceable>user</replaceable> <rep
Like <literal>md5</literal> method but uses older crypt
encryption, which is needed for pre-7.2 clients.
<literal>md5</literal> is preferred for 7.2 and later clients.
See <xref linkend="auth-password"> for details.
</para>
</listitem>
</varlistentry>
@ -247,6 +263,7 @@ hostssl <replaceable>database</replaceable> <replaceable>user</replaceable> <rep
<para>
Same as "md5", but the password is sent in cleartext over the
network. This should not be used on untrusted networks.
See <xref linkend="auth-password"> for details.
</para>
</listitem>
</varlistentry>
@ -256,7 +273,8 @@ hostssl <replaceable>database</replaceable> <replaceable>user</replaceable> <rep
<listitem>
<para>
Kerberos V4 is used to authenticate the user. This is only
available for TCP/IP connections.
available for TCP/IP connections. See <xref
linkend="kerberos-auth"> for details.
</para>
</listitem>
</varlistentry>
@ -266,7 +284,8 @@ hostssl <replaceable>database</replaceable> <replaceable>user</replaceable> <rep
<listitem>
<para>
Kerberos V5 is used to authenticate the user. This is only
available for TCP/IP connections.
available for TCP/IP connections. See <xref
linkend="kerberos-auth"> for details.
</para>
</listitem>
</varlistentry>
@ -274,39 +293,33 @@ hostssl <replaceable>database</replaceable> <replaceable>user</replaceable> <rep
<varlistentry>
<term><literal>ident</></term>
<listitem>
<para>
For TCP/IP connections, authentication is done by contacting
the <firstterm>ident</firstterm> server on the client
host. This is only as secure as the client machine. You must
specify the map name after the 'ident' keyword. It
determines how to map remote user names to
<productname>PostgreSQL</productname> user names. If you use
"sameuser", the user names are assumed to be identical. If
not, the map name is looked up in the $PGDATA/pg_ident.conf
<para>
Obtain the operating system user name of the client (for
TCP/IP connections by contacting the ident server on the
client, for local connections by getting it from the
operating system) and check if the user is allowed to
connect as the requested database user by consulting the map
specified after the <literal>ident</literal> key word.
</para>
<para>
If you use the map <literal>sameuser</literal>, the user
names are assumed to be identical. If not, the map name is
looked up in the <literal>$PGDATA/pg_ident.conf</literal>
file. The connection is accepted if that file contains an
entry for this map name with the ident-supplied user name
and the requested <productname>PostgreSQL</productname> user
name.
</para>
<para>
On machines that support unix-domain socket credentials
(currently Linux, FreeBSD, NetBSD, and BSD/OS), ident allows
reliable authentication of 'local' connections without ident
running on the local machine.
For local connections, this only works on machines that
support Unix-domain socket credentials (currently Linux,
FreeBSD, NetBSD, and BSD/OS).
</para>
<para>
On systems without <symbol>SO_PEERCRED</> requests, ident
authentication is only available for TCP/IP connections. As a
work around, it is possible to specify the <systemitem
class="systemname">localhost</> address <systemitem
class="systemname">127.0.0.1</> and make connections to this
address.
</para>
<para>
Following the <literal>ident</> keyword, an <firstterm>ident
map</firstterm> name should be supplied which specifies which
operating system users equate with which database users. See
below for details.
See <xref linkend="auth-ident"> below for details.
</para>
</listitem>
</varlistentry>
@ -315,27 +328,27 @@ hostssl <replaceable>database</replaceable> <replaceable>user</replaceable> <rep
<term><literal>pam</></term>
<listitem>
<para>
This authentication type operates similarly to
<firstterm>password</firstterm> except that it uses PAM
(Pluggable Authentication Modules) as the authentication
mechanism. The default PAM service name is
<literal>postgresql</literal>. You can optionally supply you
own service name after the <literal>pam</> keyword in the
file. For more information about PAM, please read the <ulink
url="http://www.kernel.org/pub/linux/libs/pam/"><productname>Linux-PAM</>
Page</ulink> and the <ulink
url="http://www.sun.com/software/solaris/pam/"><systemitem
class="osname">Solaris</> PAM Page</ulink>.
Authenticate using the Pluggable Authentication Modules
(PAM) service provided by the operating system. See <xref
linkend="auth-pam"> for details.
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><replaceable>authentication-option</replaceable></term>
<listitem>
<para>
The meaning of this optional field depends on the chosen
authentication method and is described in the next section.
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
@ -353,6 +366,13 @@ hostssl <replaceable>database</replaceable> <replaceable>user</replaceable> <rep
range of allowed client IP addresses.
</para>
<important>
<para>
Do not prevent the superuser from accessing the template1
database. Various utility commands need access to template1.
</para>
</important>
<para>
<indexterm>
<primary>SIGHUP</primary>
@ -373,55 +393,67 @@ hostssl <replaceable>database</replaceable> <replaceable>user</replaceable> <rep
<example id="example-pg-hba.conf">
<title>An example <filename>pg_hba.conf</filename> file</title>
<programlisting>
# TYPE DATABASE USER IP_ADDRESS MASK AUTHTYPE
# Allow any user on the local system to connect to any database under
# any user name using Unix-domain sockets (the default for local
# connections).
#
# TYPE DATABASE USER IP-ADDRESS IP-MASK METHOD
local all all trust
# Allow any user on the local system to connect to any
# database under any user name, but only via an IP connection:
# The same using local loopback TCP/IP connections.
#
# TYPE DATABASE USER IP-ADDRESS IP-MASK METHOD
host all all 127.0.0.1 255.255.255.255 trust
host all all 127.0.0.1 255.255.255.255 trust
# Allow any user from any host with IP address 192.168.93.x to connect
# to database "template1" as the same user name that ident reports for
# the connection (typically the Unix user name).
#
# TYPE DATABASE USER IP-ADDRESS IP-MASK METHOD
host template1 all 192.168.93.0 255.255.255.0 ident sameuser
# The same, over Unix-socket connections:
# Allow a user from host 192.168.12.10 to connect to database
# "template1" if the user's password is correctly supplied.
#
# TYPE DATABASE USER IP-ADDRESS IP-MASK METHOD
host template1 all 192.168.12.10 255.255.255.255 md5
local all all trust
# In the absence of preceding "host" lines, these two lines will
# reject all connection from 192.168.54.1 (since that entry will be
# matched first), but allow Kerberos V connections from anywhere else
# on the Internet. The zero mask means that no bits of the host IP
# address are considered so it matches any host.
#
# TYPE DATABASE USER IP-ADDRESS IP-MASK METHOD
host all all 192.168.54.1 255.255.255.255 reject
host all all 0.0.0.0 0.0.0.0 krb5
# Allow any user from any host with IP address 192.168.93.x to
# connect to database "template1" as the same user name that ident on that
# host identifies him as (typically his Unix user name):
# Allow users from 192.168.x.x hosts to connect to any database, if
# they pass the ident check. If, for example, ident says the user is
# "bryanh" and he requests to connect as PostgreSQL user "guest1", the
# connection is allowed if there is an entry in pg_ident.conf for map
# "omicron" that says "bryanh" is allowed to connect as "guest1".
#
# TYPE DATABASE USER IP-ADDRESS IP-MASK METHOD
host all all 192.168.0.0 255.255.0.0 ident omicron
host template1 all 192.168.93.0 255.255.255.0 ident sameuser
# If these are the only three lines for local connections, they will
# allow local users to connect only to their own databases (databases
# with the same name as their user name) except for administrators and
# members of group "support" who may connect to all databases. The file
# $PGDATA/admins contains a list of user names. Passwords are required in
# all cases.
#
# TYPE DATABASE USER IP-ADDRESS IP-MASK METHOD
local sameuser all md5
local all @admins md5
local all +support md5
# Allow a user from host 192.168.12.10 to connect to database "template1"
# if the user's password is correctly supplied:
# The last two lines above can be combined into a single line:
local all @admins,+support md5
host template1 all 192.168.12.10 255.255.255.255 md5
# In the absence of preceding "host" lines, these two lines will reject
# all connection attempts from 192.168.54.1 (since that entry will be
# matched first), but allow Kerberos V5-validated connections from anywhere
# else on the Internet. The zero mask means that no bits of the host IP
# address are considered, so it matches any host:
host all all 192.168.54.1 255.255.255.255 reject
host all all 0.0.0.0 0.0.0.0 krb5
# Allow users from 192.168.x.x hosts to connect to any database, if they
# pass the ident check. If, for example, ident says the user is "bryanh"
# and he requests to connect as <productname>PostgreSQL</> user "guest1", the connection
# is allowed if there is an entry in pg_ident.conf for map "omicron" that
# says "bryanh" is allowed to connect as "guest1":
host all all 192.168.0.0 255.255.0.0 ident omicron
# If these are the only two lines for local connections, they will allow
# local users to connect only to their own databases (database named the
# same as the user name), except for administrators who may connect to
# all databases. The file $PGDATA/admins lists the user names who are
# permitted to connect to all databases. Passwords are required in all
# cases. (If you prefer to use ident authorization, an ident map can
# serve a parallel purpose to the password list file used here.)
local sameuser all md5
local all @admins md5
# The database column can also use lists and file names, but not groups:
local db1,db2,@demodbs all md5
</programlisting>
</example>
</para>
@ -542,10 +574,10 @@ local all @admins md5
<productname>Kerberos</productname> system is far beyond the scope
of this document; in all generality it can be quite complex (yet
powerful). The <ulink
url="http://www.nrl.navy.mil/CCS/people/kenh/kerberos-faq.html">Kerb
eros <acronym>FAQ</></ulink> or <ulink
url="ftp://athena-dist.mit.edu">MIT Project Athena</ulink> can be a
good starting point for exploration. Several sources for
url="http://www.nrl.navy.mil/CCS/people/kenh/kerberos-faq.html">Kerberos
<acronym>FAQ</></ulink> or <ulink
url="ftp://athena-dist.mit.edu">MIT Project Athena</ulink> can be
a good starting point for exploration. Several sources for
<productname>Kerberos</> distributions exist.
</para>
@ -620,13 +652,25 @@ local all @admins md5
</sect2>
<sect2>
<sect2 id="auth-ident">
<title>Ident-based authentication</title>
<indexterm>
<primary>ident</primary>
</indexterm>
<para>
The ident authentication method works by inspecting the client's
operating system user name and determining the allowed database
user names by using a map file that lists the permitted
corresponding user name pairs. The determination of the client's
user name is the security-critical point, and it works differently
depending on the connection type.
</para>
<sect3>
<title>Ident Authentication over TCP/IP</title>
<para>
The <quote>Identification Protocol</quote> is described in
<citetitle>RFC 1413</citetitle>. Virtually every Unix-like
@ -660,15 +704,35 @@ local all @admins md5
</para>
</blockquote>
</para>
</sect3>
<sect3>
<title>Ident Authentication over Local Sockets</title>
<para>
On systems supporting <symbol>SO_PEERCRED</symbol> requests for
Unix-domain sockets, ident authentication can also be applied to
local connections. In this case, no security risk is added by using
ident authentication; indeed it is a preferable choice for local
connections on such systems.
Unix-domain sockets (currently <systemitem
class="osname">Linux</>, <systemitem class="osname">FreeBSD</>,
<systemitem class="osname">NetBSD</>, and <systemitem
class="osname">BSD/OS</>, ident authentication can also be applied
to local connections. In this case, no security risk is added by
using ident authentication; indeed it is a preferable choice for
local connections on such systems.
</para>
<para>
On systems without <symbol>SO_PEERCRED</> requests, ident
authentication is only available for TCP/IP connections. As a
work around, it is possible to specify the <systemitem
class="systemname">localhost</> address <systemitem
class="systemname">127.0.0.1</> and make connections to this
address.
</para>
</sect3>
<sect3>
<title>Ident Maps</title>
<para>
When using ident-based authentication, after having determined the
name of the operating system user that initiated the connection,
@ -731,16 +795,35 @@ local all @admins md5
<example id="example-pg-ident.conf">
<title>An example <filename>pg_ident.conf</> file</title>
<programlisting>
#MAP IDENT-NAME POSTGRESQL-NAME
# MAPNAME IDENT-USERNAME PG-USERNAME
omicron bryanh bryanh
omicron ann ann
omicron bryanh bryanh
omicron ann ann
# bob has user name robert on these machines
omicron robert bob
omicron robert bob
# bryanh can also connect as guest1
omicron bryanh guest1
omicron bryanh guest1
</programlisting>
</example>
</sect3>
</sect2>
<sect2 id="auth-pam">
<title>PAM Authentication</title>
<para>
This authentication type operates similarly to
<firstterm>password</firstterm> except that it uses PAM (Pluggable
Authentication Modules) as the authentication mechanism. The
default PAM service name is <literal>postgresql</literal>. You can
optionally supply you own service name after the <literal>pam</>
keyword in the file. For more information about PAM, please read
the <ulink
url="http://www.kernel.org/pub/linux/libs/pam/"><productname>Linux-PAM</>
Page</ulink> and the <ulink
url="http://www.sun.com/software/solaris/pam/"><systemitem
class="osname">Solaris</> PAM Page</ulink>.
</para>
</sect2>
</sect1>