Adding usernames to pg_hba.conf - Mailing list pgsql-patches
| From | Bruce Momjian |
|---|---|
| Subject | Adding usernames to pg_hba.conf |
| Date | |
| Msg-id | 200203190555.g2J5t7d14306@candle.pha.pa.us Whole thread Raw |
| Responses |
Re: Adding usernames to pg_hba.conf
(Peter Eisentraut <peter_e@gmx.net>)
|
| List | pgsql-patches |
This patch completes the following TODO item:
* Allow usernames to be specified directly in pg_hba.conf (Bruce)
Currently, we allow usernames in secondary password files, but this is a
very confusing feature. This patch:
o removes secondary password file support
o adds a user name column just after the database column
o allows a comma separated list of usernames or databases
o allows another file to contain a list of username/databases
by preceding the pg_hba.conf entry with '@'
o allow single or double-quoting of user/database names
See the documentation changes and new pg_hba.conf diffs for samples.
Is the '@' sign a good way to identify a file name? Is putting the
username column just after the database column the right place for it?
--
Bruce Momjian | http://candle.pha.pa.us
pgman@candle.pha.pa.us | (610) 853-3000
+ If your life is a hard drive, | 830 Blythe Avenue
+ Christ can be your backup. | Drexel Hill, Pennsylvania 19026
Index: doc/src/sgml/client-auth.sgml
===================================================================
RCS file: /cvsroot/pgsql/doc/src/sgml/client-auth.sgml,v
retrieving revision 1.32
diff -c -r1.32 client-auth.sgml
*** doc/src/sgml/client-auth.sgml 20 Jan 2002 22:19:55 -0000 1.32
--- doc/src/sgml/client-auth.sgml 19 Mar 2002 05:51:45 -0000
***************
*** 10,23 ****
</indexterm>
<para>
! When a client application connects to the database server, it specifies which
! <productname>PostgreSQL</productname> user name it wants to connect as,
! much the same way one logs into a Unix computer as a particular user.
! Within the SQL environment the active
! database user name determines access privileges to database
! objects -- see <xref linkend="user-manag"> for more information
! about that. It is therefore obviously essential to restrict which
! database user name(s) a given client can connect as.
</para>
<para>
--- 10,23 ----
</indexterm>
<para>
! When a client application connects to the database server, it
! specifies which <productname>PostgreSQL</productname> user name it
! wants to connect as, much the same way one logs into a Unix computer
! as a particular user. Within the SQL environment the active database
! user name determines access privileges to database objects -- see
! <xref linkend="user-manag"> for more information about that. It is
! therefore obviously essential to restrict which database user name(s)
! a given client can connect as.
</para>
<para>
***************
*** 30,49 ****
<para>
<productname>PostgreSQL</productname> offers a number of different
! client authentication methods. The method to be used can be selected
! on the basis of (client) host and database; some authentication methods
! allow you to restrict by user name as well.
</para>
<para>
! <productname>PostgreSQL</productname> database user names are logically
separate from user names of the operating system in which the server
! runs. If all the users of a particular server also have accounts on
the server's machine, it makes sense to assign database user names
! that match their operating system user names. However, a server that accepts remote
! connections may have many users who have no local account, and in such
! cases there need be no connection between database user names and OS
! user names.
</para>
<sect1 id="pg-hba-conf">
--- 30,48 ----
<para>
<productname>PostgreSQL</productname> offers a number of different
! client authentication methods. The method to be used can be selected
! on the basis of (client) host, database, and user.
</para>
<para>
! <productname>PostgreSQL</productname> user names are logically
separate from user names of the operating system in which the server
! runs. If all the users of a particular server also have accounts on
the server's machine, it makes sense to assign database user names
! that match their operating system user names. However, a server that
! accepts remote connections may have many users who have no local
! account, and in such cases there need be no connection between
! database user names and OS user names.
</para>
<sect1 id="pg-hba-conf">
***************
*** 56,94 ****
<para>
Client authentication is controlled by the file
<filename>pg_hba.conf</filename> in the data directory, e.g.,
! <filename>/usr/local/pgsql/data/pg_hba.conf</filename>. (<acronym>HBA</> stands
! for host-based authentication.) A default <filename>pg_hba.conf</filename>
! file is installed when the
! data area is initialized by <command>initdb</command>.
</para>
<para>
! The general format of the <filename>pg_hba.conf</filename> file is
! of a set of records, one per line. Blank lines and lines beginning
! with a hash character (<quote>#</quote>) are ignored. A record is
! made up of a number of fields which are separated by spaces and/or
! tabs. Records cannot be continued across lines.
</para>
<para>
Each record specifies a connection type, a client IP address range
! (if relevant for the connection type), a database name or names,
and the authentication method to be used for connections matching
! these parameters.
! The first record that matches the type, client address, and requested
! database name of a connection attempt is used to do the
! authentication step. There is no <quote>fall-through</> or
<quote>backup</>: if one record is chosen and the authentication
! fails, the following records are not considered. If no record
! matches, the access will be denied.
</para>
<para>
A record may have one of the three formats
<synopsis>
! local <replaceable>database</replaceable> <replaceable>authentication-method</replaceable> [
<replaceable>authentication-option</replaceable>]
! host <replaceable>database</replaceable> <replaceable>IP-address</replaceable> <replaceable>IP-mask</replaceable>
<replaceable>authentication-method</replaceable>[ <replaceable>authentication-option</replaceable> ]
! hostssl <replaceable>database</replaceable> <replaceable>IP-address</replaceable> <replaceable>IP-mask</replaceable>
<replaceable>authentication-method</replaceable>[ <replaceable>authentication-option</replaceable> ]
</synopsis>
The meaning of the fields is as follows:
--- 55,93 ----
<para>
Client authentication is controlled by the file
<filename>pg_hba.conf</filename> in the data directory, e.g.,
! <filename>/usr/local/pgsql/data/pg_hba.conf</filename>.
! (<acronym>HBA</> stands for host-based authentication.) A default
! <filename>pg_hba.conf</filename> file is installed when the data area
! is initialized by <command>initdb</command>.
</para>
<para>
! The general format of the <filename>pg_hba.conf</filename> file is of
! a set of records, one per line. Blank lines are ignored, as is any
! text after the <quote>#</quote> comment character. A record is made
! up of a number of fields which are separated by spaces and/or tabs.
! Fields can contain white space if the field value is quoted. Records
! cannot be continued across lines.
</para>
<para>
Each record specifies a connection type, a client IP address range
! (if relevant for the connection type), a database name, a user name,
and the authentication method to be used for connections matching
! these parameters. The first record with a matching connection type,
! client address, requested database, and user name is used to peform
! authentication. There is no <quote>fall-through</> or
<quote>backup</>: if one record is chosen and the authentication
! fails, subsequent records are not considered. If no record matches,
! access is denied.
</para>
<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>
</synopsis>
The meaning of the fields is as follows:
***************
*** 97,103 ****
<term><literal>local</literal></term>
<listitem>
<para>
! This record pertains to connection attempts over Unix domain
sockets.
</para>
</listitem>
--- 96,102 ----
<term><literal>local</literal></term>
<listitem>
<para>
! This record applies to connection attempts using Unix domain
sockets.
</para>
</listitem>
***************
*** 107,116 ****
<term><literal>host</literal></term>
<listitem>
<para>
! This record pertains to connection attempts over TCP/IP
! networks. Note that TCP/IP connections are completely disabled
! unless the server is started with the <option>-i</option> switch or
! the equivalent configuration parameter is set.
</para>
</listitem>
</varlistentry>
--- 106,116 ----
<term><literal>host</literal></term>
<listitem>
<para>
! This record applied to 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</>
! configuration parameter is enabled.
</para>
</listitem>
</varlistentry>
***************
*** 119,131 ****
<term><literal>hostssl</literal></term>
<listitem>
<para>
! This record pertains to connection attempts with 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 match only SSL connections.)
</para>
</listitem>
</varlistentry>
--- 119,131 ----
<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 requires SSL connections.)
</para>
</listitem>
</varlistentry>
***************
*** 134,145 ****
<term><replaceable>database</replaceable></term>
<listitem>
<para>
! Specifies the database that this record applies to. 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. Otherwise,
! this is the name of a specific <productname>PostgreSQL</productname>
! database.
</para>
</listitem>
</varlistentry>
--- 134,165 ----
<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. 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>
!
! <varlistentry>
! <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.
! Otherwise, this is the name of a specific
! <productname>PostgreSQL</productname> user. Multiple user
! names can be supplied by separating them with commas. 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</>.
</para>
</listitem>
</varlistentry>
***************
*** 149,158 ****
<term><replaceable>IP mask</replaceable></term>
<listitem>
<para>
! These two fields specify to which client machines a
! <literal>host</literal> or <literal>hostssl</literal>
! record applies, based on their IP
! address. (Of course IP addresses can be spoofed but this
consideration is beyond the scope of
<productname>PostgreSQL</productname>.) The precise logic is that
<blockquote>
--- 169,177 ----
<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
<blockquote>
***************
*** 169,178 ****
<term><replaceable>authentication method</replaceable></term>
<listitem>
<para>
! Specifies the method that users must use to authenticate themselves
! when connecting under the control of this authentication record.
! The possible choices are summarized here,
! details are in <xref linkend="auth-methods">.
<variablelist>
<varlistentry>
--- 188,196 ----
<term><replaceable>authentication method</replaceable></term>
<listitem>
<para>
! Specifies the authentication method to use when connecting via
! this record. The possible choices are summarized here; details
! are in <xref linkend="auth-methods">.
<variablelist>
<varlistentry>
***************
*** 190,255 ****
<term><literal>reject</></term>
<listitem>
<para>
! The connection is rejected unconditionally. This is mostly
! useful to <quote>filter out</> certain hosts from a group.
</para>
</listitem>
</varlistentry>
<varlistentry>
! <term><literal>password</></term>
<listitem>
<para>
! The client is required to supply a password which is required to
! match the database password that was set up for the user.
! </para>
!
! <para>
! An optional file name may be specified after the
! <literal>password</literal> keyword. This file is expected to
! contain a list of users who may connect using this record,
! and optionally alternative passwords for them.
! </para>
!
! <para>
! The password is sent over the wire in clear text. For better
! protection, use the <literal>md5</literal> or
! <literal>crypt</literal> methods.
</para>
</listitem>
</varlistentry>
<varlistentry>
! <term><literal>md5</></term>
<listitem>
<para>
! Like the <literal>password</literal> method, but the password
! is sent over the wire encrypted using a simple
! challenge-response protocol. This protects against incidental
! wire-sniffing. This is now the recommended choice for
! password-based authentication.
! </para>
!
! <para>
! The name of a file may follow the
! <literal>md5</literal> keyword. It contains a list of users
! who may connect using this record.
</para>
</listitem>
</varlistentry>
<varlistentry>
! <term><literal>crypt</></term>
<listitem>
<para>
! Like the <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. The <literal>crypt</>
! method is not compatible with encrypting passwords in
! <filename>pg_shadow</>, and may fail if client and server
! machines have different implementations of the crypt() library
! routine.
</para>
</listitem>
</varlistentry>
--- 208,248 ----
<term><literal>reject</></term>
<listitem>
<para>
! The connection is rejected unconditionally. This is useful for
! <quote>filtering out</> certain hosts from a group.
</para>
</listitem>
</varlistentry>
<varlistentry>
! <term><literal>md5</></term>
<listitem>
<para>
! Requires the client to supply an MD5 encrypted password for
! authentication. This is the only method that allows encrypted
! passwords to be stored in pg_shadow.
</para>
</listitem>
</varlistentry>
<varlistentry>
! <term><literal>crypt</></term>
<listitem>
<para>
! 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.
</para>
</listitem>
</varlistentry>
<varlistentry>
! <term><literal>password</></term>
<listitem>
<para>
! Same as "md5", but the password is sent in cleartext over the
! network. This should not be used on untrusted networks.
! </para>
</para>
</listitem>
</varlistentry>
***************
*** 278,311 ****
<term><literal>ident</></term>
<listitem>
<para>
! The identity of the user as determined on login to the
! operating system is used by <productname>PostgreSQL</productname>
! to determine whether the user
! is allowed to connect as the requested database user.
! For TCP/IP connections the user's identity is determined by
! contacting the <firstterm>ident</firstterm> server on the client
! host. (Note that this is only as reliable as the remote ident
! server; ident authentication should never be used for remote hosts
! whose administrators are not trustworthy.)
! On operating systems
! supporting <symbol>SO_PEERCRED</> requests for Unix domain sockets,
! ident authentication is possible for local connections;
! the system is then asked for the connecting user's identity.
</para>
<para>
! On systems without <symbol>SO_PEERCRED</> requests, ident authentication
! is only available for TCP/IP connections. As a workaround,
! 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>
! The <replaceable>authentication option</replaceable> following
! the <literal>ident</> keyword specifies the name of an
! <firstterm>ident map</firstterm> that specifies which operating
! system users equate with which database users. See below for
! details.
</para>
</listitem>
</varlistentry>
--- 271,306 ----
<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 PostgreSQL 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
! file. The connection is accepted if that file contains an
! entry for this map name with the ident-supplied username and
! the requested PostgreSQL username.
! </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.
! </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.
</para>
</listitem>
</varlistentry>
***************
*** 315,331 ****
<listitem>
<para>
This authentication type operates similarly to
! <firstterm>password</firstterm>, with the main difference that
! it will use PAM (Pluggable Authentication Modules) as the
! authentication mechanism. The <replaceable>authentication
! option</replaceable> following the <literal>pam</> keyword
! specifies the service name that will be passed to PAM. The
! default service name is <literal>postgresql</literal>.
! For more information about PAM, please read the <ulink
! url="http://www.kernel.org/pub/linux/libs/pam/"><productname>Linux-PAM</productname>
! Page</ulink> and/or the <ulink
! url="http://www.sun.com/software/solaris/pam/"><systemitem class="osname">Solaris</> PAM
! Page</ulink>.
</para>
</listitem>
</varlistentry>
--- 310,325 ----
<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>L
! inux-PAM</productname> Page</ulink> and the <ulink
! url="http://www.sun.com/software/solaris/pam/"><systemitem
! class="osname">Solaris</> PAM Page</ulink>.
</para>
</listitem>
</varlistentry>
***************
*** 336,377 ****
</listitem>
</varlistentry>
- <varlistentry>
- <term><replaceable>authentication option</replaceable></term>
- <listitem>
- <para>
- This field is interpreted differently depending on the
- authentication method, as described above.
- </para>
- </listitem>
- </varlistentry>
</variablelist>
</para>
<para>
Since the <filename>pg_hba.conf</filename> records are examined
sequentially for each connection attempt, the order of the records is
! very significant. Typically, earlier records will have tight
! connection match parameters and weaker authentication methods,
! while later records will have looser match parameters and stronger
! authentication methods. For example, one might wish to use
! <literal>trust</> authentication for local TCP connections but
! require a password for remote TCP connections. In this case a
! record specifying <literal>trust</> authentication for connections
! from 127.0.0.1 would appear before a record specifying password
! authentication for a wider range of allowed client IP addresses.
</para>
<para>
<indexterm>
<primary>SIGHUP</primary>
</indexterm>
! The <filename>pg_hba.conf</filename> file is read on startup
! and when the <application>postmaster</> receives a
<systemitem>SIGHUP</systemitem> signal. If you edit the file on an
active system, you will need to signal the <application>postmaster</>
! (using <literal>pg_ctl reload</> or <literal>kill -HUP</>)
! to make it re-read the file.
</para>
<para>
--- 330,362 ----
</listitem>
</varlistentry>
</variablelist>
</para>
<para>
Since the <filename>pg_hba.conf</filename> records are examined
sequentially for each connection attempt, the order of the records is
! significant. Typically, earlier records will have tight connection
! match parameters and weaker authentication methods, while later
! records will have looser match parameters and stronger authentication
! methods. For example, one might wish to use <literal>trust</>
! authentication for local TCP connections but require a password for
! remote TCP connections. In this case a record specifying
! <literal>trust</> authentication for connections from 127.0.0.1 would
! appear before a record specifying password authentication for a wider
! range of allowed client IP addresses.
</para>
<para>
<indexterm>
<primary>SIGHUP</primary>
</indexterm>
! The <filename>pg_hba.conf</filename> file is read on startup and when
! the <application>postmaster</> receives a
<systemitem>SIGHUP</systemitem> signal. If you edit the file on an
active system, you will need to signal the <application>postmaster</>
! (using <literal>pg_ctl reload</> or <literal>kill -HUP</>) to make it
! re-read the file.
</para>
<para>
***************
*** 382,408 ****
<example id="example-pg-hba.conf">
<title>An example <filename>pg_hba.conf</filename> file</title>
<programlisting>
! # TYPE DATABASE IP_ADDRESS MASK AUTHTYPE MAP
# Allow any user on the local system to connect to any
# database under any username, but only via an IP connection:
! host all 127.0.0.1 255.255.255.255 trust
# The same, over Unix-socket connections:
! local all trust
# Allow any user from any host with IP address 192.168.93.x to
# connect to database "template1" as the same username that ident on that
# host identifies him as (typically his Unix username):
! host template1 192.168.93.0 255.255.255.0 ident sameuser
# Allow a user from host 192.168.12.10 to connect to database "template1"
! # if the user's password in pg_shadow is correctly supplied:
! host template1 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
--- 367,393 ----
<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 username, but only via an IP connection:
! host all all 127.0.0.1 255.255.255.255 trust
# The same, over Unix-socket connections:
! local all all trust
# Allow any user from any host with IP address 192.168.93.x to
# connect to database "template1" as the same username that ident on that
# host identifies him as (typically his Unix username):
! host template1 all 192.168.93.0 255.255.255.0 ident sameuser
# Allow a user from host 192.168.12.10 to connect to database "template1"
! # if the user's password is correctly supplied:
! 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
***************
*** 410,417 ****
# 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 192.168.54.1 255.255.255.255 reject
! host 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"
--- 395,402 ----
# 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"
***************
*** 419,425 ****
# 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 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
--- 404,410 ----
# 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
***************
*** 429,436 ****
# 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 md5
! local all md5 admins
</programlisting>
</example>
</para>
--- 414,421 ----
# 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
</programlisting>
</example>
</para>
***************
*** 490,575 ****
<title>Password authentication</title>
<indexterm>
! <primary>password</primary>
</indexterm>
<indexterm>
! <primary>MD5</>
</indexterm>
<para>
Password-based authentication methods include <literal>md5</>,
! <literal>crypt</>, and <literal>password</>. These methods operate
similarly except for the way that the password is sent across the
! connection. If you are at all concerned about password <quote>sniffing</>
! attacks then <literal>md5</> is preferred, with <literal>crypt</> a
! second choice if you must support obsolete clients. Plain
! <literal>password</> should especially be avoided for connections over
! the open Internet (unless you use SSL, SSH, or other communications
! security wrappers around the connection).
</para>
<para>
! <productname>PostgreSQL</productname> database passwords are separate from
! operating system user passwords. Ordinarily, the password for each
! database user is stored in the pg_shadow system catalog table.
! Passwords can be managed with the query language commands
! <command>CREATE USER</command> and <command>ALTER USER</command>,
! e.g., <userinput>CREATE USER foo WITH PASSWORD
! 'secret';</userinput>. By default, that is, if no password has
! been set up, the stored password is <literal>NULL</literal>
! and password authentication will always fail for that user.
</para>
<para>
To restrict the set of users that are allowed to connect to certain
! databases, list the set of users in a separate file (one user name
! per line) in the same directory that <filename>pg_hba.conf</> is in,
! and mention the (base) name of the file after the
! <literal>password</>, <literal>md5</>, or <literal>crypt</> keyword,
! respectively, in <filename>pg_hba.conf</>. If you do not use this
! feature, then any user that is known to the database system can
! connect to any database (so long as he supplies the correct password,
! of course).
! </para>
!
! <para>
! These files can also be used to apply a different set of passwords
! to a particular database or set thereof. In that case, the files
! have a format similar to the standard Unix password file
! <filename>/etc/passwd</filename>, that is,
! <synopsis>
! <replaceable>username</replaceable>:<replaceable>password</replaceable>
! </synopsis>
! Any extra colon-separated fields following the password are
! ignored. The password is expected to be encrypted using the
! system's <function>crypt()</function> function. The utility
! program <application>pg_passwd</application> that is installed
! with <productname>PostgreSQL</productname> can be used to manage
! these password files.
! </para>
!
! <para>
! Lines with and without passwords can be mixed in secondary
! password files. Lines without password indicate use of the main
! password in <literal>pg_shadow</> that is managed by
! <command>CREATE USER</> and <command>ALTER USER</>. Lines with
! passwords will cause that password to be used. A password entry of
! <quote>+</quote> also means using the pg_shadow password.
! </para>
!
! <para>
! Alternative passwords cannot be used when using the <literal>md5</>
! or <literal>crypt</> methods. The file will be read as
! usual, but the password field will simply be ignored and the
! <literal>pg_shadow</> password will always be used.
! </para>
!
! <para>
! Note that using alternative passwords like this means that one can
! no longer use <command>ALTER USER</command> to change one's
! password. It will appear to work but the password one is
! changing is not the password that the system will end up
! using.
</para>
</sect2>
--- 475,522 ----
<title>Password authentication</title>
<indexterm>
! <primary>MD5</>
</indexterm>
<indexterm>
! <primary>crypt</>
! </indexterm>
! <indexterm>
! <primary>password</primary>
</indexterm>
<para>
Password-based authentication methods include <literal>md5</>,
! <literal>crypt</>, and <literal>password</>. These methods operate
similarly except for the way that the password is sent across the
! connection. If you are at all concerned about password
! <quote>sniffing</> attacks then <literal>md5</> is preferred, with
! <literal>crypt</> a second choice if you must support pre-7.2
! clients. Plain <literal>password</> should especially be avoided for
! connections over the open Internet (unless you use SSL, SSH, or
! other communications security wrappers around the connection).
</para>
<para>
! <productname>PostgreSQL</productname> database passwords are
! separate from operating system user passwords. Ordinarily, the
! password for each database user is stored in the pg_shadow system
! catalog table. Passwords can be managed with the query language
! commands <command>CREATE USER</command> and <command>ALTER
! USER</command>, e.g., <userinput>CREATE USER foo WITH PASSWORD
! 'secret';</userinput>. By default, that is, if no password has been
! set up, the stored password is <literal>NULL</literal> and password
! authentication will always fail for that user.
</para>
<para>
To restrict the set of users that are allowed to connect to certain
! databases, list the users separated by commas, or in a separate
! file. The file should contain user names separated by commas or one
! user name per line, and be in the same directory as
! <filename>pg_hba.conf</>. Mention the (base) name of the file
! preceded by <literal>@</>in the <literal>USER</> column. The
! <literal>DATABASE</> column can similarly accept a list of values or
! a file name.
</para>
</sect2>
***************
*** 588,597 ****
<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">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>
--- 535,544 ----
<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
<productname>Kerberos</> distributions exist.
</para>
***************
*** 606,639 ****
<para>
<productname>PostgreSQL</> operates like a normal Kerberos service.
The name of the service principal is
! <replaceable>servicename/hostname@realm</>, where
! <replaceable>servicename</> is <literal>postgres</literal>
! (unless a different service name was selected at configure time
! with <literal>./configure --with-krb-srvnam=whatever</>).
! <replaceable>hostname</> is the fully qualified domain name of the server
! machine. The service principal's realm is the preferred realm of the
! server machine.
</para>
<para>
! Client principals must have their <productname>PostgreSQL</> user name as
! their first component, for example
! <replaceable>pgusername/otherstuff@realm</>.
! At present the realm of the client is not checked by
! <productname>PostgreSQL</>; so
! if you have cross-realm authentication enabled, then any principal
! in any realm that can communicate with yours will be accepted.
</para>
<para>
! Make sure that your server key file is readable (and
! preferably only readable) by the
! <productname>PostgreSQL</productname> server account (see
! <xref linkend="postgres-user">). The location of the key file
! is specified with the <varname>krb_server_keyfile</> run time
! configuration parameter. (See also <xref linkend="runtime-config">.)
! The default is <filename>/etc/srvtab</> if you are using Kerberos 4
! and <filename>FILE:/usr/local/pgsql/etc/krb5.keytab</> (or whichever
directory was specified as <varname>sysconfdir</> at build time)
with Kerberos 5.
</para>
--- 553,585 ----
<para>
<productname>PostgreSQL</> operates like a normal Kerberos service.
The name of the service principal is
! <replaceable>servicename/hostname@realm</>, where
! <replaceable>servicename</> is <literal>postgres</literal> (unless a
! different service name was selected at configure time with
! <literal>./configure --with-krb-srvnam=whatever</>).
! <replaceable>hostname</> is the fully qualified domain name of the
! server machine. The service principal's realm is the preferred realm
! of the server machine.
</para>
<para>
! Client principals must have their <productname>PostgreSQL</> user
! name as their first component, for example
! <replaceable>pgusername/otherstuff@realm</>. At present the realm of
! the client is not checked by <productname>PostgreSQL</>; so if you
! have cross-realm authentication enabled, then any principal in any
! realm that can communicate with yours will be accepted.
</para>
<para>
! Make sure that your server key file is readable (and preferably only
! readable) by the <productname>PostgreSQL</productname> server
! account (see <xref linkend="postgres-user">). The location of the
! key file is specified with the <varname>krb_server_keyfile</> run
! time configuration parameter. (See also <xref
! linkend="runtime-config">.) The default is <filename>/etc/srvtab</>
! if you are using Kerberos 4 and
! <filename>FILE:/usr/local/pgsql/etc/krb5.keytab</> (or whichever
directory was specified as <varname>sysconfdir</> at build time)
with Kerberos 5.
</para>
***************
*** 649,666 ****
<para>
When connecting to the database make sure you have a ticket for a
! principal matching the requested database user name.
! An example: For database user name <literal>fred</>, both principal
<literal>fred@EXAMPLE.COM</> and
! <literal>fred/users.example.com@EXAMPLE.COM</> can be
! used to authenticate to the database server.
</para>
<para>
! If you use <application>mod_auth_krb</application> and <application>mod_perl</application> on your
<productname>Apache</productname>web server,
! you can use <literal>AuthType KerberosV5SaveCredentials</literal> with a <application>mod_perl</application>
! script. This gives secure database access over the web, no extra
! passwords required.
</para>
</sect2>
--- 595,614 ----
<para>
When connecting to the database make sure you have a ticket for a
! principal matching the requested database user name. An example: For
! database user name <literal>fred</>, both principal
<literal>fred@EXAMPLE.COM</> and
! <literal>fred/users.example.com@EXAMPLE.COM</> can be used to
! authenticate to the database server.
</para>
<para>
! If you use <application>mod_auth_krb</application> and
! <application>mod_perl</application> on your
! <productname>Apache</productname> web server, you can use
! <literal>AuthType KerberosV5SaveCredentials</literal> with a
! <application>mod_perl</application> script. This gives secure
! database access over the web, no extra passwords required.
</para>
</sect2>
***************
*** 707,761 ****
</para>
<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 a system.
</para>
<para>
When using ident-based authentication, after having determined the
name of the operating system user that initiated the connection,
! <productname>PostgreSQL</productname> checks whether that user is allowed
! to connect as the database user he is requesting to connect as.
! This is controlled by the ident map
! argument that follows the <literal>ident</> keyword in the
! <filename>pg_hba.conf</filename> file. There is a predefined ident map
! <literal>sameuser</literal>, which allows any operating system
! user to connect as the database user of the same name (if the
! latter exists). Other maps must be created manually.
</para>
<para>
! <indexterm><primary>pg_ident.conf</primary></indexterm>
! Ident maps other than <literal>sameuser</literal> are defined
! in the file <filename>pg_ident.conf</filename>
! in the data directory, which contains lines of the general form:
<synopsis>
<replaceable>map-name</> <replaceable>ident-username</> <replaceable>database-username</>
</synopsis>
! Comments and whitespace are handled in the usual way.
! The <replaceable>map-name</> is an arbitrary name that will be
! used to refer to this mapping in <filename>pg_hba.conf</filename>.
! The other two fields specify which operating system user is
! allowed to connect as which database user. The same
! <replaceable>map-name</> can be used repeatedly to specify more
! user-mappings within a single map. There is no restriction regarding
! how many
! database users a given operating system user may correspond to and vice
! versa.
</para>
<para>
<indexterm>
<primary>SIGHUP</primary>
</indexterm>
! The <filename>pg_ident.conf</filename> file is read on startup
! and when the <application>postmaster</> receives a
<systemitem>SIGHUP</systemitem> signal. If you edit the file on an
active system, you will need to signal the <application>postmaster</>
! (using <literal>pg_ctl reload</> or <literal>kill -HUP</>)
! to make it re-read the file.
</para>
<para>
--- 655,708 ----
</para>
<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.
</para>
<para>
When using ident-based authentication, after having determined the
name of the operating system user that initiated the connection,
! <productname>PostgreSQL</productname> checks whether that user is
! allowed to connect as the database user he is requesting to connect
! as. This is controlled by the ident map argument that follows the
! <literal>ident</> keyword in the <filename>pg_hba.conf</filename>
! file. There is a predefined ident map <literal>sameuser</literal>,
! which allows any operating system user to connect as the database
! user of the same name (if the latter exists). Other maps must be
! created manually.
</para>
<para>
! <indexterm><primary>pg_ident.conf</primary></indexterm> Ident maps
! other than <literal>sameuser</literal> are defined in the file
! <filename>pg_ident.conf</filename> in the data directory, which
! contains lines of the general form:
<synopsis>
<replaceable>map-name</> <replaceable>ident-username</> <replaceable>database-username</>
</synopsis>
! Comments and whitespace are handled in the usual way. The
! <replaceable>map-name</> is an arbitrary name that will be used to
! refer to this mapping in <filename>pg_hba.conf</filename>. The other
! two fields specify which operating system user is allowed to connect
! as which database user. The same <replaceable>map-name</> can be
! used repeatedly to specify more user-mappings within a single map.
! There is no restriction regarding how many database users a given
! operating system user may correspond to and vice versa.
</para>
<para>
<indexterm>
<primary>SIGHUP</primary>
</indexterm>
! The <filename>pg_ident.conf</filename> file is read on startup and
! when the <application>postmaster</> receives a
<systemitem>SIGHUP</systemitem> signal. If you edit the file on an
active system, you will need to signal the <application>postmaster</>
! (using <literal>pg_ctl reload</> or <literal>kill -HUP</>) to make it
! re-read the file.
</para>
<para>
***************
*** 763,775 ****
conjunction with the <filename>pg_hba.conf</> file in <xref
linkend="example-pg-hba.conf"> is shown in <xref
linkend="example-pg-ident.conf">. In this example setup, anyone
! logged in to a machine on the 192.168 network that does not have
! the Unix user name <systemitem>bryanh</>, <systemitem>ann</>, or <systemitem>robert</> would not be granted
access.
! Unix user <systemitem>robert</> would only be allowed access when he tries to
! connect as <productname>PostgreSQL</> user <systemitem>bob</>,
! not as <systemitem>robert</>
! or anyone else. <systemitem>ann</> would only be allowed to connect as
! <systemitem>ann</>. User <systemitem>bryanh</> would be allowed to connect as either
<systemitem>bryanh</> himself or as <systemitem>guest1</>.
</para>
--- 710,723 ----
conjunction with the <filename>pg_hba.conf</> file in <xref
pgsql-patches by date: