Allow krb_realm (krb5, gssapi and sspi) and krb_server_hostname (krb5 only)

authentication options to be set in pg_hba.conf on a per-line basis, to
override the defaults set in postgresql.conf.

doc/src/sgml/client-auth.sgml

-<!-- $PostgreSQL: pgsql/doc/src/sgml/client-auth.sgml,v 1.115 2009/01/02 11:51:53 mha Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/client-auth.sgml,v 1.116 2009/01/07 12:38:10 mha Exp $ -->
 
 <chapter id="client-authentication">
  <title>Client Authentication</title>
@@ -784,6 +784,26 @@ omicron       bryanh            guest1
        </para>
       </listitem>
      </varlistentry>
+
+     <varlistentry>
+      <term>krb_realm</term>
+      <listitem>
+       <para>
+        Overrides the <xref linkend="guc-krb-realm"> parameter, setting which realm
+        to verify the authenticated user principal against.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry>
+      <term>krb_server_hostname</term>
+      <listitem>
+       <para>
+        Overrides the <xref linkend="guc-krb-server-hostname"> parameter, setting which
+        hostname will be used for the server principal when using Kerberos.
+       </para>
+      </listitem>
+     </varlistentry>
     </variablelist>
    </para>
   </sect2>
@@ -825,6 +845,16 @@ omicron       bryanh            guest1
        </para>
       </listitem>
      </varlistentry>
+
+     <varlistentry>
+      <term>krb_realm</term>
+      <listitem>
+       <para>
+        Overrides the <xref linkend="guc-krb-realm"> parameter, setting which realm
+        to verify the authenticated user principal against.
+       </para>
+      </listitem>
+     </varlistentry>
     </variablelist>
    </para>
   </sect2>

src/backend/libpq/auth.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/libpq/auth.c,v 1.175 2009/01/01 17:23:42 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/libpq/auth.c,v 1.176 2009/01/07 12:38:11 mha Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -611,7 +611,7 @@ recv_and_check_password_packet(Port *port)
 #ifdef KRB5
 
 static int
-pg_krb5_init(void)
+pg_krb5_init(Port *port)
 {
 	krb5_error_code retval;
 	char	   *khostname;
@@ -645,7 +645,10 @@ pg_krb5_init(void)
 	 * If no hostname was specified, pg_krb_server_hostname is already NULL.
 	 * If it's set to blank, force it to NULL.
 	 */
-	khostname = pg_krb_server_hostname;
+	if (port->hba->krb_server_hostname)
+		khostname = port->hba->krb_server_hostname;
+	else
+		khostname = pg_krb_server_hostname;
 	if (khostname && khostname[0] == '\0')
 		khostname = NULL;
 
@@ -691,11 +694,12 @@ pg_krb5_recvauth(Port *port)
 	krb5_ticket *ticket;
 	char	   *kusername;
 	char	   *cp;
+	char	   *realmmatch;
 
 	if (get_role_line(port->user_name) == NULL)
 		return STATUS_ERROR;
 
-	ret = pg_krb5_init();
+	ret = pg_krb5_init(port);
 	if (ret != STATUS_OK)
 		return ret;
 
@@ -736,25 +740,30 @@ pg_krb5_recvauth(Port *port)
 		return STATUS_ERROR;
 	}
 
+	if (port->hba->krb_realm)
+		realmmatch = port->hba->krb_realm;
+	else
+		realmmatch = pg_krb_realm;
+
 	cp = strchr(kusername, '@');
 	if (cp)
 	{
 		*cp = '\0';
 		cp++;
 
-		if (pg_krb_realm != NULL && strlen(pg_krb_realm))
+		if (realmmatch != NULL && strlen(realmmatch))
 		{
 			/* Match realm against configured */
 			if (pg_krb_caseins_users)
-				ret = pg_strcasecmp(pg_krb_realm, cp);
+				ret = pg_strcasecmp(realmmatch, cp);
 			else
-				ret = strcmp(pg_krb_realm, cp);
+				ret = strcmp(realmmatch, cp);
 
 			if (ret)
 			{
 				elog(DEBUG2,
 					 "krb5 realm (%s) and configured realm (%s) don't match",
-					 cp, pg_krb_realm);
+					 cp, realmmatch);
 
 				krb5_free_ticket(pg_krb5_context, ticket);
 				krb5_auth_con_free(pg_krb5_context, auth_context);
@@ -762,7 +771,7 @@ pg_krb5_recvauth(Port *port)
 			}
 		}
 	}
-	else if (pg_krb_realm && strlen(pg_krb_realm))
+	else if (realmmatch && strlen(realmmatch))
 	{
 		elog(DEBUG2,
 			 "krb5 did not return realm but realm matching was requested");
@@ -859,6 +868,7 @@ pg_GSS_recvauth(Port *port)
 	int			ret;
 	StringInfoData buf;
 	gss_buffer_desc gbuf;
+	char	   *realmmatch;
 
 	/*
 	 * GSS auth is not supported for protocol versions before 3, because it
@@ -1018,6 +1028,11 @@ pg_GSS_recvauth(Port *port)
 					 gettext_noop("retrieving GSS user name failed"),
 					 maj_stat, min_stat);
 
+	if (port->hba->krb_realm)
+		realmmatch = port->hba->krb_realm;
+	else
+		realmmatch = pg_krb_realm;
+
 	/*
 	 * Split the username at the realm separator
 	 */
@@ -1028,28 +1043,28 @@ pg_GSS_recvauth(Port *port)
 		*cp = '\0';
 		cp++;
 
-		if (pg_krb_realm != NULL && strlen(pg_krb_realm))
+		if (realmmatch != NULL && strlen(realmmatch))
 		{
 			/*
 			 * Match the realm part of the name first
 			 */
 			if (pg_krb_caseins_users)
-				ret = pg_strcasecmp(pg_krb_realm, cp);
+				ret = pg_strcasecmp(realmmatch, cp);
 			else
-				ret = strcmp(pg_krb_realm, cp);
+				ret = strcmp(realmmatch, cp);
 
 			if (ret)
 			{
 				/* GSS realm does not match */
 				elog(DEBUG2,
 				   "GSSAPI realm (%s) and configured realm (%s) don't match",
-					 cp, pg_krb_realm);
+					 cp, realmmatch);
 				gss_release_buffer(&lmin_s, &gbuf);
 				return STATUS_ERROR;
 			}
 		}
 	}
-	else if (pg_krb_realm && strlen(pg_krb_realm))
+	else if (realmmatch && strlen(realmmatch))
 	{
 		elog(DEBUG2,
 			 "GSSAPI did not return realm but realm matching was requested");
@@ -1113,6 +1128,7 @@ pg_SSPI_recvauth(Port *port)
 	SID_NAME_USE accountnameuse;
 	HMODULE		secur32;
 	QUERY_SECURITY_CONTEXT_TOKEN_FN _QuerySecurityContextToken;
+	char	   *realmmatch;
 
 	/*
 	 * SSPI auth is not supported for protocol versions before 3, because it
@@ -1325,13 +1341,18 @@ pg_SSPI_recvauth(Port *port)
 	 * Compare realm/domain if requested. In SSPI, always compare case
 	 * insensitive.
 	 */
-	if (pg_krb_realm && strlen(pg_krb_realm))
+	if (port->hba->krb_realm)
+		realmmatch = port->hba->krb_realm;
+	else
+		realmmatch = pg_krb_realm;
+
+	if (realmmatch && strlen(realmmatch))
 	{
-		if (pg_strcasecmp(pg_krb_realm, domainname))
+		if (pg_strcasecmp(realmmatch, domainname))
 		{
 			elog(DEBUG2,
 				 "SSPI domain (%s) and configured domain (%s) don't match",
-				 domainname, pg_krb_realm);
+				 domainname, realmmatch);
 
 			return STATUS_ERROR;
 		}

src/backend/libpq/hba.c

@@ -10,7 +10,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/libpq/hba.c,v 1.178 2009/01/02 11:34:03 mha Exp $
+ *	  $PostgreSQL: pgsql/src/backend/libpq/hba.c,v 1.179 2009/01/07 12:38:11 mha Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1040,6 +1040,19 @@ parse_hba_line(List *line, int line_num, HbaLine *parsedline)
 				REQUIRE_AUTH_OPTION(uaLDAP, "ldapsuffix", "ldap");
 				parsedline->ldapsuffix = pstrdup(c);
 			}
+			else if (strcmp(token, "krb_server_hostname") == 0)
+			{
+				REQUIRE_AUTH_OPTION(uaKrb5, "krb_server_hostname", "krb5");
+				parsedline->krb_server_hostname = pstrdup(c);
+			}
+			else if (strcmp(token, "krb_realm") == 0)
+			{
+				if (parsedline->auth_method != uaKrb5 &&
+					parsedline->auth_method != uaGSS &&
+					parsedline->auth_method != uaSSPI)
+					INVALID_AUTH_OPTION("krb_realm", "krb5, gssapi and sspi");
+				parsedline->krb_realm = pstrdup(c);
+			}
 			else
 			{
 				ereport(LOG,
@@ -1242,6 +1255,10 @@ free_hba_record(HbaLine *record)
 		pfree(record->ldapprefix);
 	if (record->ldapsuffix)
 		pfree(record->ldapsuffix);
+	if (record->krb_server_hostname)
+		pfree(record->krb_server_hostname);
+	if (record->krb_realm)
+		pfree(record->krb_realm);
 }
 
 /*

src/include/libpq/hba.h

@@ -4,7 +4,7 @@
  *	  Interface to hba.c
  *
  *
- * $PostgreSQL: pgsql/src/include/libpq/hba.h,v 1.53 2008/11/20 11:48:26 mha Exp $
+ * $PostgreSQL: pgsql/src/include/libpq/hba.h,v 1.54 2009/01/07 12:38:11 mha Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -56,6 +56,8 @@ typedef struct
 	char	   *ldapprefix;
 	char	   *ldapsuffix;
 	bool		clientcert;
+	char	   *krb_server_hostname;
+	char	   *krb_realm;
 } HbaLine;
 
 typedef struct Port hbaPort;