mgr/dashboard: fix error when enabling SSO with cert. file

Nautilus dedicated fix: added py2 compatibility code.
Also:
* Disabled security setting 'wantNameIdEncrypted': not all Identity Providers support this and we are already requiring encrypted assertions (which is the default).

Fixes: https://tracker.ceph.com/issues/44666
Signed-off-by: Alfonso Martínez <almartin@redhat.com>

src/pybind/mgr/dashboard/services/sso.py

@@ -4,6 +4,7 @@
 
 import errno
 import json
+import six
 import sys
 import threading
 
@@ -186,13 +187,13 @@ def handle_sso_command(cmd):
             # pylint: disable=redefined-builtin
             FileNotFoundError = IOError
         try:
-            f = open(sp_x_509_cert, 'r')
+            f = open(sp_x_509_cert, 'r', encoding='utf-8') if six.PY3 else open(sp_x_509_cert, 'rb')
             sp_x_509_cert = f.read()
             f.close()
         except FileNotFoundError:
             pass
         try:
-            f = open(sp_private_key, 'r')
+            f = open(sp_private_key, 'r', encoding='utf-8') if six.PY3 else open(sp_private_key, 'rb')
             sp_private_key = f.read()
             f.close()
         except FileNotFoundError:
@@ -204,7 +205,7 @@ def handle_sso_command(cmd):
         # pylint: disable=broad-except
         except Exception:
             try:
-                f = open(idp_metadata, 'r')
+                f = open(idp_metadata, 'r', encoding='utf-8') if six.PY3 else open(idp_metadata, 'rb')
                 idp_metadata = f.read()
                 f.close()
             except FileNotFoundError:
@@ -250,7 +251,7 @@ def handle_sso_command(cmd):
                 "wantMessagesSigned": has_sp_cert,
                 "wantAssertionsSigned": has_sp_cert,
                 "wantAssertionsEncrypted": has_sp_cert,
-                "wantNameIdEncrypted": has_sp_cert,
+                "wantNameIdEncrypted": False,  # Not all Identity Providers support this.
                 "metadataValidUntil": '',
                 "wantAttributeStatement": False
             }