From 9b3449f033d5bf86a055bba7c9bcb1ca97c7d8b6 Mon Sep 17 00:00:00 2001
From: M66B <M66B@users.noreply.github.com>
Date: Sat, 8 Jan 2022 19:43:26 +0100
Subject: [PATCH] TLS local

---
 FAQ.md                                           |  3 +--
 .../java/eu/faircode/email/ConnectionHelper.java |  4 +++-
 .../java/eu/faircode/email/MessageHelper.java    | 16 ++++++++++++----
 3 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/FAQ.md b/FAQ.md
index b96acb6306..18d02b2443 100644
--- a/FAQ.md
+++ b/FAQ.md
@@ -4483,8 +4483,7 @@ A message will be consired safely transported if *every* [Received](https://data
 * has a *with* with the value 'HTTP', 'HTTPS', or 'HTTPREST'
 * has a *with* with the value '[xMTPSx](https://datatracker.ietf.org/doc/html/rfc3848)' ('xMTPAx' is considered insecure)
 
-A local address is a local host address, a site local address
-or a non-numeric address which isn't [a domain name](https://developer.android.com/reference/androidx/core/util/PatternsCompat#DOMAIN_NAME).
+A local address is a local host address, a site local address or a link local address.
 
 Example:
 
diff --git a/app/src/main/java/eu/faircode/email/ConnectionHelper.java b/app/src/main/java/eu/faircode/email/ConnectionHelper.java
index 462b111a60..2c15b1a7fb 100644
--- a/app/src/main/java/eu/faircode/email/ConnectionHelper.java
+++ b/app/src/main/java/eu/faircode/email/ConnectionHelper.java
@@ -509,7 +509,9 @@ public class ConnectionHelper {
     static boolean isLocalAddress(String host) {
         try {
             InetAddress addr = ConnectionHelper.from6to4(InetAddress.getByName(host));
-            return (addr.isSiteLocalAddress() || addr.isLinkLocalAddress());
+            return (addr.isLoopbackAddress() ||
+                    addr.isSiteLocalAddress() ||
+                    addr.isLinkLocalAddress());
         } catch (UnknownHostException ex) {
             Log.e(ex);
             return false;
diff --git a/app/src/main/java/eu/faircode/email/MessageHelper.java b/app/src/main/java/eu/faircode/email/MessageHelper.java
index 42d06240d1..416432efb0 100644
--- a/app/src/main/java/eu/faircode/email/MessageHelper.java
+++ b/app/src/main/java/eu/faircode/email/MessageHelper.java
@@ -2202,18 +2202,26 @@ public class MessageHelper {
 
     private static boolean isLocal(String value) {
         if (value.contains("localhost") ||
-                value.contains("[127.0.0.1]") ||
+                value.contains("127.0.0.1") ||
                 value.contains("[::1]"))
             return true;
+
+        int s = value.indexOf('[');
+        int e = value.indexOf(']', s + 1);
+        if (s >= 0 && e > 0) {
+            String ip = value.substring(s + 1, e);
+            if (ConnectionHelper.isNumericAddress(ip) &&
+                    ConnectionHelper.isLocalAddress(ip))
+                return true;
+        }
+
         int f = value.indexOf(' ');
         String host = (f < 0 ? value : value.substring(0, f));
         if (ConnectionHelper.isNumericAddress(host)) {
             if (ConnectionHelper.isLocalAddress(host))
                 return true;
-        } else {
-            if (!PatternsCompat.DOMAIN_NAME.matcher(host).matches())
-                return true;
         }
+
         return false;
     }