disable the PGP section if the mailbox is proton and not has PGP enabled (#1841)

* disable the PGP section if the mailbox is proton and not has PGP enabled

* fix format

---------

Co-authored-by: Son NK <son@simplelogin.io>

app/dashboard/views/mailbox_detail.py

@@ -30,7 +30,7 @@ class ChangeEmailForm(FlaskForm):
 @dashboard_bp.route("/mailbox/<int:mailbox_id>/", methods=["GET", "POST"])
 @login_required
 def mailbox_detail_route(mailbox_id):
-    mailbox = Mailbox.get(mailbox_id)
+    mailbox: Mailbox = Mailbox.get(mailbox_id)
     if not mailbox or mailbox.user_id != current_user.id:
         flash("You cannot see this page", "warning")
         return redirect(url_for("dashboard.index"))
@@ -144,6 +144,15 @@ def mailbox_detail_route(mailbox_id):
                         url_for("dashboard.mailbox_detail_route", mailbox_id=mailbox_id)
                     )
 
+                if mailbox.is_proton():
+                    flash(
+                        "Enabling PGP for a Proton Mail mailbox is redundant and does not add any security benefit",
+                        "info",
+                    )
+                    return redirect(
+                        url_for("dashboard.mailbox_detail_route", mailbox_id=mailbox_id)
+                    )
+
                 mailbox.pgp_public_key = request.form.get("pgp")
                 try:
                     mailbox.pgp_finger_print = load_public_key_and_check(

app/dns_utils.py

@@ -34,7 +34,7 @@ def get_cname_record(hostname) -> Optional[str]:
 
 
 def get_mx_domains(hostname) -> [(int, str)]:
-    """return list of (priority, domain name).
+    """return list of (priority, domain name) sorted by priority (lowest priority first)
     domain name ends with a "." at the end.
     """
     try:
@@ -50,7 +50,7 @@ def get_mx_domains(hostname) -> [(int, str)]:
 
         ret.append((int(parts[0]), parts[1]))
 
-    return ret
+    return sorted(ret, key=lambda prio_domain: prio_domain[0])
 
 
 _include_spf = "include:"

app/models.py

@@ -30,6 +30,8 @@ from sqlalchemy_utils import ArrowType
 from app import config
 from app import s3
 from app.db import Session
+from app.dns_utils import get_mx_domains
+
 from app.errors import (
     AliasInTrashError,
     DirectoryInTrashError,
@@ -2569,6 +2571,27 @@ class Mailbox(Base, ModelMixin):
             + Alias.filter_by(mailbox_id=self.id).count()
         )
 
+    def is_proton(self) -> bool:
+        if (
+            self.email.endswith("@proton.me")
+            or self.email.endswith("@protonmail.com")
+            or self.email.endswith("@protonmail.ch")
+            or self.email.endswith("@pm.me")
+        ):
+            return True
+
+        from app.email_utils import get_email_local_part
+
+        mx_domains: [(int, str)] = get_mx_domains(get_email_local_part(self.email))
+        # Proton is the first domain
+        if mx_domains and mx_domains[0][1] in (
+            "mail.protonmail.ch.",
+            "mailsec.protonmail.ch.",
+        ):
+            return True
+
+        return False
+
     @classmethod
     def delete(cls, obj_id):
         mailbox: Mailbox = cls.get(obj_id)

templates/dashboard/mailbox_detail.html

@@ -71,7 +71,18 @@
         </form>
       </div>
       <!-- END Change email -->
-      {% if mailbox.pgp_finger_print and not mailbox.disable_pgp and current_user.include_sender_in_reverse_alias %}
+      <!-- Not show PGP option for Proton mailbox -->
+      {% if mailbox.is_proton() and not mailbox.pgp_enabled() %}
+
+        <div class="alert alert-info">
+          As an email is always encrypted at rest in Proton Mail, having SimpleLogin also encrypt your email is redundant and does not add any security benefit.
+          <br>
+          The PGP option on SimpleLogin is instead useful for when your mailbox provider isn't encrypted by default like Gmail, Outlook, etc.
+        </div>
+      {% endif %}
+      <div class="{% if mailbox.is_proton() and not mailbox.pgp_enabled() %}
+         disabled-content{% endif %}">
+        {% if mailbox.pgp_finger_print and not mailbox.disable_pgp and current_user.include_sender_in_reverse_alias and not mailbox.is_proton() %}
 
           <div class="alert alert-info">
             Email headers like <span class="italic">From, To, Subject</span> aren't encrypted by PGP.
@@ -164,6 +175,7 @@
               </div>
             </form>
           </div>
+        </div>
         <hr />
         <h2 class="h4">Advanced Options</h2>
         {% if spf_available %}