Add BSD authentication method.

Create a "bsd" auth method that works the same as "password" so far as
clients are concerned, but calls the BSD Authentication service to
check the password.  This is currently only available on OpenBSD.

Marisa Emerson, reviewed by Thomas Munro

configure

@@ -827,6 +827,7 @@ with_python
 with_gssapi
 with_krb_srvnam
 with_pam
+with_bsd_auth
 with_ldap
 with_bonjour
 with_openssl
@@ -1516,6 +1517,7 @@ Optional Packages:
   --with-krb-srvnam=NAME  default service principal name in Kerberos (GSSAPI)
                           [postgres]
   --with-pam              build with PAM support
+  --with-bsd-auth         build with BSD Authentication support
   --with-ldap             build with LDAP support
   --with-bonjour          build with Bonjour support
   --with-openssl          build with OpenSSL support
@@ -5570,6 +5572,41 @@ fi
 $as_echo "$with_pam" >&6; }
 
 
+#
+# BSD AUTH
+#
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether to build with BSD Authentication support" >&5
+$as_echo_n "checking whether to build with BSD Authentication support... " >&6; }
+
+
+
+# Check whether --with-bsd-auth was given.
+if test "${with_bsd_auth+set}" = set; then :
+  withval=$with_bsd_auth;
+  case $withval in
+    yes)
+
+$as_echo "#define USE_BSD_AUTH 1" >>confdefs.h
+
+      ;;
+    no)
+      :
+      ;;
+    *)
+      as_fn_error $? "no argument expected for --with-bsd-auth option" "$LINENO" 5
+      ;;
+  esac
+
+else
+  with_bsd_auth=no
+
+fi
+
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $with_bsd_auth" >&5
+$as_echo "$with_bsd_auth" >&6; }
+
+
 #
 # LDAP
 #
@@ -10522,6 +10559,17 @@ fi
 
 done
 
+fi
+
+if test "$with_bsd_auth" = yes ; then
+  ac_fn_c_check_header_mongrel "$LINENO" "bsd_auth.h" "ac_cv_header_bsd_auth_h" "$ac_includes_default"
+if test "x$ac_cv_header_bsd_auth_h" = xyes; then :
+
+else
+  as_fn_error $? "header file <bsd_auth.h> is required for BSD Authentication support" "$LINENO" 5
+fi
+
+
 fi
 
 if test "$with_systemd" = yes ; then

configure.in

@@ -673,6 +673,16 @@ PGAC_ARG_BOOL(with, pam, no,
 AC_MSG_RESULT([$with_pam])
 
 
+#
+# BSD AUTH
+#
+AC_MSG_CHECKING([whether to build with BSD Authentication support])
+PGAC_ARG_BOOL(with, bsd-auth, no,
+              [build with BSD Authentication support],
+              [AC_DEFINE([USE_BSD_AUTH], 1, [Define to 1 to build with BSD Authentication support. (--with-bsd-auth)])])
+AC_MSG_RESULT([$with_bsd_auth])
+
+
 #
 # LDAP
 #
@@ -1269,6 +1279,10 @@ if test "$with_pam" = yes ; then
                                      [AC_MSG_ERROR([header file <security/pam_appl.h> or <pam/pam_appl.h> is required for PAM.])])])
 fi
 
+if test "$with_bsd_auth" = yes ; then
+  AC_CHECK_HEADER(bsd_auth.h, [], [AC_MSG_ERROR([header file <bsd_auth.h> is required for BSD Authentication support])])
+fi
+
 if test "$with_systemd" = yes ; then
   AC_CHECK_HEADER(systemd/sd-daemon.h, [], [AC_MSG_ERROR([header file <systemd/sd-daemon.h> is required for systemd support])])
 fi

doc/src/sgml/client-auth.sgml

@@ -522,6 +522,16 @@ hostnossl  <replaceable>database</replaceable>  <replaceable>user</replaceable>
          </para>
         </listitem>
        </varlistentry>
+
+       <varlistentry>
+        <term><literal>bsd</></term>
+        <listitem>
+         <para>
+          Authenticate using the BSD Authentication service provided by the
+          operating system. See <xref linkend="auth-bsd"> for details.
+         </para>
+        </listitem>
+       </varlistentry>
       </variablelist>
 
       </para>
@@ -1662,6 +1672,41 @@ host ... ldap ldapurl="ldap://ldap.example.net/dc=example,dc=net?uid?sub"
     </para>
    </note>
   </sect2>
+
+  <sect2 id="auth-bsd">
+   <title>BSD Authentication</title>
+
+   <indexterm zone="auth-bsd">
+    <primary>BSD Authentication</primary>
+   </indexterm>
+
+   <para>
+    This authentication method operates similarly to
+    <literal>password</literal> except that it uses BSD Authentication
+    to verify the password. BSD Authentication is used only
+    to validate user name/password pairs. Therefore the user's role must
+    already exist in the database before BSD Authentication can be used
+    for authentication. The BSD Authentication framework is currently
+    only available on OpenBSD.
+   </para>
+
+   <para>
+    BSD Authentication in <productname>PostgreSQL</> uses
+    the <literal>auth-postgresql</literal> login type and authenticates with
+    the <literal>postgresql</literal> login class if that's defined
+    in <filename>login.conf</filename>. By default that login class does not
+    exist, and <productname>PostgreSQL</> will use the default login class.
+   </para>
+
+   <note>
+    <para>
+     To use BSD Authentication, the PostgreSQL user account (that is, the
+     operating system user running the server) must first be added to
+     the <literal>auth</literal> group.  The <literal>auth</literal> group
+     exists by default on OpenBSD systems.
+    </para>
+   </note>
+  </sect2>
  </sect1>
 
   <sect1 id="client-authentication-problems">

doc/src/sgml/installation.sgml

@@ -792,6 +792,17 @@ su - postgres
        </listitem>
       </varlistentry>
 
+      <varlistentry>
+       <term><option>--with-bsd-auth</option></term>
+       <listitem>
+        <para>
+         Build with BSD Authentication support.
+         (The BSD Authentication framework is
+         currently only available on OpenBSD.)
+        </para>
+       </listitem>
+      </varlistentry>
+
       <varlistentry>
        <term><option>--with-ldap</option></term>
        <listitem>

src/backend/libpq/auth.c

@@ -88,6 +88,17 @@ static Port *pam_port_cludge;	/* Workaround for passing "Port *port" into
 #endif   /* USE_PAM */
 
 
+/*----------------------------------------------------------------
+ * BSD authentication
+ *----------------------------------------------------------------
+ */
+#ifdef USE_BSD_AUTH
+#include <bsd_auth.h>
+
+static int	CheckBSDAuth(Port *port, char *user);
+#endif   /* USE_BSD_AUTH */
+
+
 /*----------------------------------------------------------------
  * LDAP authentication
  *----------------------------------------------------------------
@@ -258,6 +269,9 @@ auth_failed(Port *port, int status, char *logdetail)
 		case uaPAM:
 			errstr = gettext_noop("PAM authentication failed for user \"%s\"");
 			break;
+		case uaBSD:
+			errstr = gettext_noop("BSD authentication failed for user \"%s\"");
+			break;
 		case uaLDAP:
 			errstr = gettext_noop("LDAP authentication failed for user \"%s\"");
 			break;
@@ -529,6 +543,14 @@ ClientAuthentication(Port *port)
 #endif   /* USE_PAM */
 			break;
 
+		case uaBSD:
+#ifdef USE_BSD_AUTH
+			status = CheckBSDAuth(port, port->user_name);
+#else
+			Assert(false);
+#endif   /* USE_BSD_AUTH */
+			break;
+
 		case uaLDAP:
 #ifdef USE_LDAP
 			status = CheckLDAPAuth(port);
@@ -1856,6 +1878,38 @@ CheckPAMAuth(Port *port, char *user, char *password)
 #endif   /* USE_PAM */
 
 
+/*----------------------------------------------------------------
+ * BSD authentication system
+ *----------------------------------------------------------------
+ */
+#ifdef USE_BSD_AUTH
+static int
+CheckBSDAuth(Port *port, char *user)
+{
+	char *passwd;
+	int retval;
+
+	/* Send regular password request to client, and get the response */
+	sendAuthRequest(port, AUTH_REQ_PASSWORD);
+
+	passwd = recv_password_packet(port);
+	if (passwd == NULL)
+		return STATUS_EOF;
+
+	/*
+	 * Ask the BSD auth system to verify password.  Note that auth_userokay
+	 * will overwrite the password string with zeroes, but it's just a
+	 * temporary string so we don't care.
+	 */
+	retval = auth_userokay(user, NULL, "auth-postgresql", passwd);
+
+	if (!retval)
+		return STATUS_ERROR;
+
+	return STATUS_OK;
+}
+#endif   /* USE_BSD_AUTH */
+
 
 /*----------------------------------------------------------------
  * LDAP authentication system

src/backend/libpq/hba.c

@@ -1189,6 +1189,12 @@ parse_hba_line(List *line, int line_num, char *raw_line)
 		parsedline->auth_method = uaPAM;
 #else
 		unsupauth = "pam";
+#endif
+	else if (strcmp(token->string, "bsd") == 0)
+#ifdef USE_BSD_AUTH
+		parsedline->auth_method = uaBSD;
+#else
+		unsupauth = "bsd";
 #endif
 	else if (strcmp(token->string, "ldap") == 0)
 #ifdef USE_LDAP

src/bin/initdb/initdb.c

@@ -90,6 +90,9 @@ static const char *const auth_methods_host[] = {
 #ifdef USE_PAM
 	"pam", "pam ",
 #endif
+#ifdef USE_BSD_AUTH
+	"bsd",
+#endif
 #ifdef USE_LDAP
 	"ldap",
 #endif
@@ -103,6 +106,9 @@ static const char *const auth_methods_local[] = {
 #ifdef USE_PAM
 	"pam", "pam ",
 #endif
+#ifdef USE_BSD_AUTH
+	"bsd",
+#endif
 #ifdef USE_LDAP
 	"ldap",
 #endif

src/include/libpq/hba.h

@@ -27,6 +27,7 @@ typedef enum UserAuth
 	uaGSS,
 	uaSSPI,
 	uaPAM,
+	uaBSD,
 	uaLDAP,
 	uaCert,
 	uaRADIUS,

src/include/pg_config.h.in

@@ -793,6 +793,9 @@
 /* Define to 1 to build with Bonjour support. (--with-bonjour) */
 #undef USE_BONJOUR
 
+/* Define to 1 to build with BSD Authentication support. (--with-bsd-auth) */
+#undef USE_BSD_AUTH
+
 /* Define to 1 if you want float4 values to be passed by value.
    (--enable-float4-byval) */
 #undef USE_FLOAT4_BYVAL

src/include/pg_config.h.win32

@@ -613,6 +613,9 @@
 /* Define to 1 to build with Bonjour support. (--with-bonjour) */
 /* #undef USE_BONJOUR */
 
+/* Define to 1 to build with BSD Authentication support. (--with-bsd-auth) */
+/* #undef USE_BSD_AUTH */
+
 /* Define to 1 if you want 64-bit integer timestamp and interval support.
    (--enable-integer-datetimes) */
 /* #undef USE_INTEGER_DATETIMES */