Allow kerberos name and username case sensitivity to be specified from
postgresql.conf.

---------------------------------------------------------------------------


Here's an updated version of the patch, with the following changes:

1) No longer uses "service name" as "application version". It's instead
hardcoded as "postgres". It could be argued that this part should be
backpatched to 8.0, but it doesn't make a big difference until you can
start changing it with GUC / connection parameters. This change only
affects kerberos 5, not 4.

2) Now downcases kerberos usernames when the client is running on win32.

3) Adds guc option for "krb_caseins_users" to make the server ignore
case mismatch which is required by some KDCs such as Active Directory.
Off by default, per discussion with Tom. This change only affects
kerberos 5, not 4.

4) Updated so it doesn't conflict with the rendevouz/bonjour patch
already in ;-)

Magnus Hagander

Author: bmomjian

configure

@@ -869,7 +869,7 @@ Optional Packages:
   --with-python           build Python modules (PL/Python)
   --with-krb4             build with Kerberos 4 support
   --with-krb5             build with Kerberos 5 support
-  --with-krb-srvnam=NAME  name of the service principal in Kerberos [postgres]
+  --with-krb-srvnam=NAME  name of the default service principal in Kerberos [postgres]
   --with-pam              build with PAM support
   --with-bonjour          build with Bonjour support
   --with-openssl          build with OpenSSL support

configure.in

@@ -1,5 +1,5 @@
 dnl Process this file with autoconf to produce a configure script.
-dnl $PostgreSQL: pgsql/configure.in,v 1.411 2005/05/15 00:26:18 momjian Exp $
+dnl $PostgreSQL: pgsql/configure.in,v 1.412 2005/06/04 20:42:41 momjian Exp $
 dnl
 dnl Developers, please strive to achieve this order:
 dnl
@@ -447,11 +447,11 @@ AC_SUBST(krb_srvtab)
 # Kerberos configuration parameters
 #
 PGAC_ARG_REQ(with, krb-srvnam,
-             [  --with-krb-srvnam=NAME  name of the service principal in Kerberos [[postgres]]],
+             [  --with-krb-srvnam=NAME  name of the default service principal in Kerberos [[postgres]]],
              [],
              [with_krb_srvnam="postgres"])
 AC_DEFINE_UNQUOTED([PG_KRB_SRVNAM], ["$with_krb_srvnam"],
-                   [Define to the name of the PostgreSQL service principal in Kerberos. (--with-krb-srvnam=NAME)])
+                   [Define to the name of the default PostgreSQL service principal in Kerberos. (--with-krb-srvnam=NAME)])
 
 
 #

doc/src/sgml/client-auth.sgml

@@ -1,5 +1,5 @@
 <!--
-$PostgreSQL: pgsql/doc/src/sgml/client-auth.sgml,v 1.79 2005/04/27 20:11:07 momjian Exp $
+$PostgreSQL: pgsql/doc/src/sgml/client-auth.sgml,v 1.80 2005/06/04 20:42:41 momjian Exp $
 -->
 
 <chapter id="client-authentication">
@@ -617,7 +617,7 @@ local   db1,db2,@demodbs  all                         md5
     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>
+    <ulink url="http://web.mit.edu/kerberos/www/">MIT Kerberos page</ulink>
     can be a good starting point for exploration.
     Several sources for <productname>Kerberos</> distributions exist.
    </para>
@@ -626,23 +626,29 @@ local   db1,db2,@demodbs  all                         md5
     While <productname>PostgreSQL</> supports both Kerberos 4 and 
     Kerberos 5, only Kerberos 5 is recommended.  Kerberos 4 is
     considered insecure and no longer recommended for general
-    use.
-   </para>
-
-   <para>
-    In order to use <productname>Kerberos</>, support for it must be
-    enabled at build time.  See <xref linkend="installation"> for more
-    information.  Both Kerberos 4 and 5 are supported, but only one
-    version can be supported in any one build.
+    use. Only one version of Kerberos can be supported in any one
+		build, and support must be enabled at build time. See
+		<xref linkend="installation"> for more information.
    </para>
 
    <para>
     <productname>PostgreSQL</> operates like a normal Kerberos service.
     The name of the service principal is
-    <literal><replaceable>servicename</>/<replaceable>hostname</>@<replaceable>realm</></literal>, where
-    <replaceable>servicename</> is <literal>postgres</literal> (unless a
-    different service name was selected at configure time with
-    <literal>./configure --with-krb-srvnam=whatever</>).
+    <literal><replaceable>servicename</>/<replaceable>hostname</>@<replaceable>realm</></literal>.
+	 </para>
+	  <para>
+    <replaceable>servicename</> can be set on the server side using the
+    <xref linkend="guc-krb-srvname"> configuration parameter, and on the
+    client side using the krbsrvname connection parameter. (See also <xref linkend="libpq-connect">.). The installation default can be changed from the default
+		<literal>postgres</literal> at build time using 
+    <literal>./configure --with-krb-srvnam=whatever</>). In most environments,
+		this parameter never needs to be changed. However, to support multiple
+		<productname>PostgreSQL</> installations on the same host it is necessary.
+		Some Kerberos implementations may also require a different service name,
+		such as Microsoft Active Directory which requires the service name
+		to be in uppercase (<literal>POSTGRES</literal>).
+	 </para>
+	 <para>
     <replaceable>hostname</> is the fully qualified host name of the
     server machine. The service principal's realm is the preferred realm
     of the server machine.
@@ -658,25 +664,26 @@ local   db1,db2,@demodbs  all                         md5
    </para>
 
    <para>
-    Make sure that your server key file is readable (and preferably
+    Make sure that your server keytab file is readable (and preferably
     only readable) by the <productname>PostgreSQL</productname> server
     account.  (See also <xref linkend="postgres-user">.) The location
     of the key file is specified by the <xref
     linkend="guc-krb-server-keyfile"> configuration
-    parameter. (See also <xref linkend="runtime-config">.) The default
+    parameter. The default
     is <filename>/etc/srvtab</> if you are using Kerberos 4 and
     <filename>/usr/local/pgsql/etc/krb5.keytab</> (or whichever
     directory was specified as <varname>sysconfdir</> at build time)
     with Kerberos 5.
    </para>
 
    <para>
-    To generate the keytab file, use for example (with version 5)
+	  The keytab file is generated in the Kerberos system, see the 
+		Kerberos documentation for details. The following example is 
+		for MIT-compatible Kerberos 5 implementations:
 <screen>
 <prompt>kadmin% </><userinput>ank -randkey postgres/server.my.domain.org</>
 <prompt>kadmin% </><userinput>ktadd -k krb5.keytab postgres/server.my.domain.org</>
 </screen>
-    Read the <productname>Kerberos</> documentation for details.
    </para>
 
    <para>

doc/src/sgml/installation.sgml

@@ -1,4 +1,4 @@
-<!-- $PostgreSQL: pgsql/doc/src/sgml/installation.sgml,v 1.233 2005/05/15 00:26:18 momjian Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/installation.sgml,v 1.234 2005/06/04 20:42:41 momjian Exp $ -->
 
 <chapter id="installation">
  <title><![%standalone-include[<productname>PostgreSQL</>]]>
@@ -816,8 +816,8 @@ su - postgres
        <term><option>--with-krb-srvnam=<replaceable>NAME</></option></term>
        <listitem>
         <para>
-         The name of the Kerberos service principal.
-         <literal>postgres</literal> is the default. There's probably no
+         The default name of the Kerberos service principal.
+         <literal>postgres</literal> is the default. There's usually no
          reason to change this.
         </para>
        </listitem>

doc/src/sgml/libpq.sgml

@@ -1,5 +1,5 @@
 <!--
-$PostgreSQL: pgsql/doc/src/sgml/libpq.sgml,v 1.181 2005/05/30 19:32:44 momjian Exp $
+$PostgreSQL: pgsql/doc/src/sgml/libpq.sgml,v 1.182 2005/06/04 20:42:41 momjian Exp $
 -->
 
  <chapter id="libpq">
@@ -279,6 +279,18 @@ PGconn *PQconnectdb(const char *conninfo);
      </listitem>
     </varlistentry>
 
+    <varlistentry>
+     <term><literal>krbsrvname</literal></term>
+     <listitem>
+      <para>
+       Kerberos service name to use when authenticating with Kerberos 4 or 5.
+       This must match the service name specified in the server
+       configuration for Kerberos authentication to succeed. (See also
+			 <xref linkend="kerberos-auth">.)
+      </para>
+     </listitem>
+    </varlistentry>
+
     <varlistentry>
      <term><literal>service</literal></term>
      <listitem>
@@ -3770,6 +3782,15 @@ setting, and is only available if
 </listitem>
 <listitem>
 <para>
+<indexterm>
+ <primary><envar>PGKRBSRVNAME</envar></primary>
+</indexterm>
+<envar>PGKRBSRVNAME</envar> sets the Kerberos service name to use when
+authenticating with Kerberos 4 or 5.
+</para>
+</listitem>
+<listitem>
+<para>
 <indexterm>
  <primary><envar>PGCONNECT_TIMEOUT</envar></primary>
 </indexterm>

doc/src/sgml/runtime.sgml

@@ -1,5 +1,5 @@
 <!--
-$PostgreSQL: pgsql/doc/src/sgml/runtime.sgml,v 1.321 2005/05/25 02:56:15 neilc Exp $
+$PostgreSQL: pgsql/doc/src/sgml/runtime.sgml,v 1.322 2005/06/04 20:42:41 momjian Exp $
 -->
 
 <chapter Id="runtime">
@@ -955,11 +955,39 @@ SET ENABLE_SEQSCAN TO OFF;
       <listitem>
        <para>
         Sets the location of the Kerberos server key file. See
-        <xref linkend="kerberos-auth"> for details.
+        <xref linkend="kerberos-auth"> for details. This parameter
+		can only be set at server start.
        </para>
       </listitem>
      </varlistentry>
 
+     <varlistentry id="guc-krb-srvname" xreflabel="krb_srvname">
+      <term><varname>krb_srvname</varname> (<type>string</type>)</term>
+      <indexterm>
+       <primary><varname>krb_srvname</> configuration parameter</primary>
+      </indexterm>
+      <listitem>
+       <para>
+        Sets the Kerberos service name. See <xref linkend="kerberos-auth">
+        for details. This parameter can only be set at server start.
+       </para>
+      </listitem>
+     </varlistentry>
+
+	 <varlistentry id="guc-krb-caseins-users" xreflabel="krb_caseins_users">
+	  <term><varname>krb_caseins_users</varname> (<type>boolean</type>)</term>
+	  <indexterm>
+	   <primary><varname>krb_caseins_users</varname> configuration parameter</primary>
+      </indexterm>
+	  <listitem>
+	   <para>
+	    Sets if Kerberos usernames should be treated case-insensitive.
+		The default is off (case sensitive). This parameter can only be
+		set at server start.
+       </para>
+	  </listitem>
+	 </varlistentry>
+
      <varlistentry id="guc-db-user-namespace" xreflabel="db_user_namespace">
       <term><varname>db_user_namespace</varname> (<type>boolean</type>)</term>
       <indexterm>

src/backend/libpq/auth.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/libpq/auth.c,v 1.123 2005/02/22 04:35:57 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/libpq/auth.c,v 1.124 2005/06/04 20:42:42 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -41,6 +41,8 @@ static char *recv_password_packet(Port *port);
 static int	recv_and_check_password_packet(Port *port);
 
 char	   *pg_krb_server_keyfile;
+char       *pg_krb_srvnam;
+bool		pg_krb_caseins_users;
 
 #ifdef USE_PAM
 #ifdef HAVE_PAM_PAM_APPL_H
@@ -99,7 +101,7 @@ pg_krb4_recvauth(Port *port)
 	status = krb_recvauth(krbopts,
 						  port->sock,
 						  &clttkt,
-						  PG_KRB_SRVNAM,
+						  pg_krb_srvnam,
 						  instance,
 						  &port->raddr.in,
 						  &port->laddr.in,
@@ -219,16 +221,16 @@ pg_krb5_init(void)
 		return STATUS_ERROR;
 	}
 
-	retval = krb5_sname_to_principal(pg_krb5_context, NULL, PG_KRB_SRVNAM,
+	retval = krb5_sname_to_principal(pg_krb5_context, NULL, pg_krb_srvnam,
 									 KRB5_NT_SRV_HST, &pg_krb5_server);
 	if (retval)
 	{
 		ereport(LOG,
 		 (errmsg("Kerberos sname_to_principal(\"%s\") returned error %d",
-				 PG_KRB_SRVNAM, retval)));
+				 pg_krb_srvnam, retval)));
 		com_err("postgres", retval,
 				"while getting server principal for service \"%s\"",
-				PG_KRB_SRVNAM);
+				pg_krb_srvnam);
 		krb5_kt_close(pg_krb5_context, pg_krb5_keytab);
 		krb5_free_context(pg_krb5_context);
 		return STATUS_ERROR;
@@ -264,7 +266,7 @@ pg_krb5_recvauth(Port *port)
 		return ret;
 
 	retval = krb5_recvauth(pg_krb5_context, &auth_context,
-						   (krb5_pointer) & port->sock, PG_KRB_SRVNAM,
+						   (krb5_pointer) & port->sock, "postgres",
 						   pg_krb5_server, 0, pg_krb5_keytab, &ticket);
 	if (retval)
 	{
@@ -303,7 +305,11 @@ pg_krb5_recvauth(Port *port)
 	}
 
 	kusername = pg_an_to_ln(kusername);
-	if (strncmp(port->user_name, kusername, SM_DATABASE_USER))
+	if (pg_krb_caseins_users)
+		ret = strncasecmp(port->user_name, kusername, SM_DATABASE_USER);
+	else
+		ret = strncmp(port->user_name, kusername, SM_DATABASE_USER);
+	if (ret)
 	{
 		ereport(LOG,
 				(errmsg("unexpected Kerberos user name received from client (received \"%s\", expected \"%s\")",

src/backend/utils/misc/guc.c

@@ -10,7 +10,7 @@
  * Written by Peter Eisentraut <peter_e@gmx.net>.
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.263 2005/05/27 18:33:30 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.264 2005/06/04 20:42:42 momjian Exp $
  *
  *--------------------------------------------------------------------
  */
@@ -63,6 +63,9 @@
 #ifndef PG_KRB_SRVTAB
 #define PG_KRB_SRVTAB ""
 #endif
+#ifndef PG_KRB_SRVNAM
+#define PG_KRB_SRVNAM ""
+#endif
 
 #define CONFIG_FILENAME	"postgresql.conf"
 #define HBA_FILENAME	"pg_hba.conf"
@@ -860,6 +863,15 @@ static struct config_bool ConfigureNamesBool[] =
 #endif
 	},
 
+	{
+		{"krb_caseins_users", PGC_POSTMASTER, CONN_AUTH_SECURITY,
+			gettext_noop("Sets if Kerberos user names should be treated case insensitive."),
+			NULL
+		},
+		&pg_krb_caseins_users,
+		false, NULL, NULL
+	},
+
 	/* End-of-list marker */
 	{
 		{NULL, 0, 0, NULL, NULL}, NULL, false, NULL, NULL
@@ -1572,6 +1584,15 @@ static struct config_string ConfigureNamesString[] =
 		PG_KRB_SRVTAB, NULL, NULL
 	},
 
+	{
+		{"krb_srvname", PGC_POSTMASTER, CONN_AUTH_SECURITY,
+			gettext_noop("Sets the name of the Kerberos service."),
+			NULL
+		},
+		&pg_krb_srvnam,
+		PG_KRB_SRVNAM, NULL, NULL
+	},
+
 	{
 		{"bonjour_name", PGC_POSTMASTER, CONN_AUTH_SETTINGS,
 			gettext_noop("Sets the Bonjour broadcast service name."),

src/backend/utils/misc/postgresql.conf.sample

@@ -64,8 +64,11 @@
 #authentication_timeout = 60	# 1-600, in seconds
 #ssl = false
 #password_encryption = true
-#krb_server_keyfile = ''
 #db_user_namespace = false
+# Kerberos
+#krb_server_keyfile = ''
+#krb_caseins_users = false
+#krb_srvname = 'postgres'
 
 
 #---------------------------------------------------------------------------

src/include/libpq/auth.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/libpq/auth.h,v 1.26 2004/12/31 22:03:32 pgsql Exp $
+ * $PostgreSQL: pgsql/src/include/libpq/auth.h,v 1.27 2005/06/04 20:42:42 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -27,5 +27,7 @@ extern void ClientAuthentication(Port *port);
 #define PG_KRB5_VERSION "PGVER5.1"
 
 extern char *pg_krb_server_keyfile;
+extern char *pg_krb_srvnam;
+extern bool pg_krb_caseins_users;
 
 #endif   /* AUTH_H */