fix(wire-format): allow UTF8 encoding for domain name

richardschneider · Jul 22, 2019 · bbeba2d · bbeba2d
1 parent 7384ded
commit bbeba2d
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Showing 3 changed files with 16 additions and 6 deletions.
diff --git a/src/WireReader.cs b/src/WireReader.cs
@@ -209,11 +209,7 @@ List<string> ReadLabels()
 
             // Read current label and remaining labels.
             var buffer = ReadBytes(length);
-            if (buffer.Any(c => c > 0x7F))
-            {
-                throw new InvalidDataException("Only ASCII characters are allowed.");
-            }
-            labels.Add(Encoding.ASCII.GetString(buffer, 0, length));
+            labels.Add(Encoding.UTF8.GetString(buffer, 0, length));
             labels.AddRange(ReadLabels());
 
             // Add to compressed names.

diff --git a/src/WireWriter.cs b/src/WireWriter.cs
@@ -286,7 +286,8 @@ public void WriteDomainName(DomainName name, bool uncompressed = false)
                 }
 
                 // Add the label
-                WriteString(label);
+                var bytes = Encoding.UTF8.GetBytes(label);
+                WriteByteLengthPrefixedBytes(bytes);
             }
 
             stream.WriteByte(0); // terminating byte

diff --git a/test/MessageTest.cs b/test/MessageTest.cs
@@ -311,5 +311,18 @@ public void Stringify_Edns()
             var text = m.ToString();
             Console.WriteLine(text);
         }
+
+        [TestMethod]
+        public void AppleMessage()
+        {
+            // A MDNS query from an Apple Host.  It contains a UTF8 domain name
+            // and an EDNS OPT-4 option.
+            var sample = "AAAAAAAGAAAAAAABCF9ob21la2l0BF90Y3AFbG9jYWwAAAyAAQ9fY29tcGFuaW9uLWxpbmvAFQAMgAEIX2FpcnBsYXnAFQAMgAEFX3Jhb3DAFQAMgAEbQ2hyaXN0b3BoZXLigJlzIE1hY0Jvb2sgUHJvwCUAEIABDF9zbGVlcC1wcm94eQRfdWRwwBoADAABAAApBaAAABGUABIABAAOAJB6e4qbc5l4e4qbc5k=";
+            var buffer1 = Convert.FromBase64String(sample);
+            var m = new Message();
+            m.Read(buffer1);
+
+            Assert.AreEqual("Christopher’s MacBook Pro", m.Questions[4].Name.Labels[0]);
+        }
     }
 }