Include <ac/unistd.h> not <sys/types.h> and <unistd.h>

Use sizeof( string ) to determine buffer size
Put authzDN in same for as used on server
(We could, just as well, set authid to "fubar" as it matters
not what it is set to)

libraries/libldap/open.c

@@ -22,8 +22,7 @@
 #include <ac/string.h>
 #include <ac/time.h>
 
-#include <unistd.h>
-#include <sys/types.h>
+#include <ac/unistd.h>
 
 #include "ldap-int.h"
 #include "ldap_log.h"
@@ -361,8 +360,11 @@ ldap_int_open_connection(
 	 * yet anyway.
 	 */
 	if( proto == LDAP_PROTO_IPC ) {
-		char authid[64];
-		sprintf( authid, "uid=%d+gid=%d", geteuid(), getegid() );
+		char authid[sizeof("uidNumber=XXXXXX,gidNumber=XXXXXX,"
+			"cn=peercred,cn=external,cn=auth")];
+		sprintf( authid, "uidNumber=%d,gidNumber=%d,"
+			"cn=peercred,cn=external,cn=auth",
+			geteuid(), getegid() );
 		ldap_int_sasl_external( ld, conn, authid, sasl_ssf );
 	}
 #endif