Add domain validation in DomainSpecificString

changelog.d/4088.bugfix

@@ -0,0 +1 @@
+Add domain validation in DomainSpecificString

synapse/crypto/context_factory.py

@@ -21,6 +21,8 @@
 from twisted.internet.ssl import CertificateOptions, ContextFactory
 from twisted.python.failure import Failure
 
+from synapse.util import encode_idna
+
 logger = logging.getLogger(__name__)
 
 
@@ -53,20 +55,6 @@ def getContext(self):
         return self._context
 
 
-def _idnaBytes(text):
-    """
-    Convert some text typed by a human into some ASCII bytes. This is a
-    copy of twisted.internet._idna._idnaBytes. For documentation, see the
-    twisted documentation.
-    """
-    try:
-        import idna
-    except ImportError:
-        return text.encode("idna")
-    else:
-        return idna.encode(text)
-
-
 def _tolerateErrors(wrapped):
     """
     Wrap up an info_callback for pyOpenSSL so that if something goes wrong
@@ -97,7 +85,7 @@ class ClientTLSOptions(object):
     def __init__(self, hostname, ctx):
         self._ctx = ctx
         self._hostname = hostname
-        self._hostnameBytes = _idnaBytes(hostname)
+        self._hostnameBytes = encode_idna(hostname)
         ctx.set_info_callback(
             _tolerateErrors(self._identityVerifyingInfoCallback)
         )

synapse/types.py

@@ -17,6 +17,7 @@
 from collections import namedtuple
 
 from synapse.api.errors import SynapseError
+from synapse.util import decode_idna, encode_idna
 
 
 class Requester(namedtuple("Requester", [
@@ -138,24 +139,43 @@ def __deepcopy__(self, memo):
     @classmethod
     def from_string(cls, s):
         """Parse the string given by 's' into a structure object."""
-        if len(s) < 1 or s[0:1] != cls.SIGIL:
-            raise SynapseError(400, "Expected %s string to start with '%s'" % (
-                cls.__name__, cls.SIGIL,
-            ))
 
-        parts = s[1:].split(':', 1)
-        if len(parts) != 2:
+        if not s.startswith(cls.SIGIL):
+            raise SynapseError(
+                400, "Expected %s string to start with %r" % (
+                    cls.__name__, cls.SIGIL,
+                )
+            )
+
+        port = None
+        try:
+            localpart, domain = s[1:].split(':', 1)
+            if ':' in domain:
+                domain, port = domain.split(':')
+        except ValueError:
             raise SynapseError(
                 400, "Expected %s of the form '%slocalname:domain'" % (
                     cls.__name__, cls.SIGIL,
                 )
             )
 
-        domain = parts[1]
+        domain = domain.strip()
+        try:
+            if domain[2:4] == '--':
+                domain = decode_idna(domain)
+            else:
+                encode_idna(domain)
+        except Exception:
+            raise SynapseError(
+                400, "%s got invalid domain name" % (cls.__name__, )
+            )
+
+        if port:
+            domain = ':'.join([domain, port])
 
         # This code will need changing if we want to support multiple domain
         # names on one HS
-        return cls(localpart=parts[0], domain=domain)
+        return cls(localpart=localpart, domain=domain)
 
     def to_string(self):
         """Return a string encoding the fields of the structure object."""

synapse/util/__init__.py

@@ -17,6 +17,8 @@
 import re
 from itertools import islice
 
+import six
+
 import attr
 
 from twisted.internet import defer, task
@@ -163,3 +165,31 @@ def glob_to_regex(glob):
 
     # \A anchors at start of string, \Z at end of string
     return re.compile(r"\A" + res + r"\Z", re.IGNORECASE)
+
+
+def encode_idna(text):
+    """
+    Convert some text typed by a human into some ASCII bytes. This is a
+    copy of twisted.internet._idna._idnaBytes. For documentation, see the
+    twisted documentation.
+    """
+    try:
+        import idna
+    except ImportError:
+        return text.encode("idna")
+    else:
+        return idna.encode(text)
+
+
+def decode_idna(text):
+    """
+    Convert some idna encoded ascii string/bytes into human form.
+    """
+    try:
+        import idna
+    except ImportError:
+        if isinstance(text, six.text_type):
+            text = text.encode('ascii')
+        return text.decode("idna")
+    else:
+        return idna.decode(text)