chore: Display errors if nomcom private key encoding fails

ietf/nomcom/templatetags/nomcom_tags.py

@@ -55,8 +55,10 @@ def formatted_email(address):
 
 @register.simple_tag
 def decrypt(string, request, year, plain=False):
-    key = retrieve_nomcom_private_key(request, year)
-
+    try:
+        key = retrieve_nomcom_private_key(request, year)
+    except UnicodeError:
+        return f"-*- Encrypted text [Error retrieving private key, contact the secretariat ({settings.SECRETARIAT_SUPPORT_EMAIL})]"
     if not key:
         return '-*- Encrypted text [No private key provided] -*-'
 

ietf/nomcom/utils.py

@@ -172,6 +172,12 @@ def command_line_safe_secret(secret):
     return base64.encodebytes(secret).decode('utf-8').rstrip()
 
 def retrieve_nomcom_private_key(request, year):
+    """Retrieve decrypted nomcom private key from the session store
+
+    Retrieves encrypted, ascii-armored private key from the session store, encodes 
+    as utf8 bytes, then decrypts. Raises UnicodeError if the value in the session
+    store cannot be encoded as utf8.
+    """
     private_key = request.session.get('NOMCOM_PRIVATE_KEY_%s' % year, None)
 
     if not private_key:
@@ -183,6 +189,7 @@ def retrieve_nomcom_private_key(request, year):
             settings.OPENSSL_COMMAND,
             command_line_safe_secret(settings.NOMCOM_APP_SECRET)
         ),
+        # The openssl command expects ascii-armored input, so utf8 encoding should be valid
         private_key.encode("utf8")
     )
     if code != 0:
@@ -191,6 +198,12 @@ def retrieve_nomcom_private_key(request, year):
 
 
 def store_nomcom_private_key(request, year, private_key):
+    """Put encrypted nomcom private key in the session store
+    
+    Encrypts the private key using openssl, then decodes the ascii-armored output
+    as utf8 and adds to the session store. Raises UnicodeError if the openssl's
+    output cannot be decoded as utf8.
+    """
     if not private_key:
         request.session['NOMCOM_PRIVATE_KEY_%s' % year] = ''
     else:
@@ -206,6 +219,7 @@ def store_nomcom_private_key(request, year, private_key):
             log("openssl error: %s:\n  Error %s: %s" %(command, code, error))        
         if error and error!=b"*** WARNING : deprecated key derivation used.\nUsing -iter or -pbkdf2 would be better.\n":
             out = b''
+        # The openssl command output in 'out' is an ascii-armored value, so should be utf8-decodable
         request.session['NOMCOM_PRIVATE_KEY_%s' % year] = out.decode("utf8")
 
 

ietf/nomcom/views.py

@@ -158,8 +158,16 @@ def private_key(request, year):
     if request.method == 'POST':
         form = PrivateKeyForm(data=request.POST)
         if form.is_valid():
-            store_nomcom_private_key(request, year, force_bytes(form.cleaned_data.get('key', '')))
-            return HttpResponseRedirect(back_url)
+            try:
+                store_nomcom_private_key(request, year, force_bytes(form.cleaned_data.get('key', '')))
+            except UnicodeError:
+                form.add_error(
+                    None, 
+                    "An internal error occurred while adding your private key to your session."
+                    f"Please contact the secretariat for assistance ({settings.SECRETARIAT_SUPPORT_EMAIL})"
+                )
+            else:
+                return HttpResponseRedirect(back_url)
     else:
         form = PrivateKeyForm()