From 2ee60783b694b6a8555a6afbef21dc1f2ca1f8b9 Mon Sep 17 00:00:00 2001
From: Aldo Cortesi <aldo@nullcube.com>
Date: Sat, 16 May 2015 11:31:53 +1200
Subject: [PATCH] websockets: client and server flavors, key and mask
 specification

---
 libpathod/language/base.py                    |  2 +
 libpathod/language/http.py                    |  2 +-
 libpathod/language/websockets.py              | 49 +++++++++++------
 libpathod/pathoc.py                           |  3 +-
 libpathod/templates/docs_lang_websockets.html | 16 +++++-
 test/test_language_websocket.py               | 53 +++++++++++++++----
 test/tutils.py                                |  1 +
 7 files changed, 96 insertions(+), 30 deletions(-)

diff --git a/libpathod/language/base.py b/libpathod/language/base.py
index 41ad639a2..3773fde1a 100644
--- a/libpathod/language/base.py
+++ b/libpathod/language/base.py
@@ -10,6 +10,7 @@ from . import generators, exceptions
 class Settings:
     def __init__(
         self,
+        is_client = False,
         staticdir = None,
         unconstrained_file_access = False,
         request_host = None,
@@ -19,6 +20,7 @@ class Settings:
         self.unconstrained_file_access = unconstrained_file_access
         self.request_host = request_host
         self.websocket_key = websocket_key
+        self.is_client = is_client
 
 
 
diff --git a/libpathod/language/http.py b/libpathod/language/http.py
index 94de7237e..070cc5f44 100644
--- a/libpathod/language/http.py
+++ b/libpathod/language/http.py
@@ -5,7 +5,7 @@ import pyparsing as pp
 
 import netlib.websockets
 from netlib import http_status, http_uastrings
-from . import base, generators, exceptions, actions, message
+from . import base, exceptions, actions, message
 
 
 class WS(base.CaselessLiteral):
diff --git a/libpathod/language/websockets.py b/libpathod/language/websockets.py
index 3abdf9d81..599cdb886 100644
--- a/libpathod/language/websockets.py
+++ b/libpathod/language/websockets.py
@@ -1,4 +1,4 @@
-
+import os
 import netlib.websockets
 import pyparsing as pp
 from . import base, generators, actions, message
@@ -115,6 +115,10 @@ class WebsocketFrame(message.Message):
     def mask(self):
         return self.tok(Mask)
 
+    @property
+    def key(self):
+        return self.tok(Key)
+
     @classmethod
     def expr(klass):
         parts = [i.expr() for i in klass.comps]
@@ -129,8 +133,21 @@ class WebsocketFrame(message.Message):
         resp = resp.setParseAction(klass)
         return resp
 
+    def resolve(self, settings, msg=None):
+        tokens = self.tokens[:]
+        if not self.mask and settings.is_client:
+            tokens.append(
+                Mask(True)
+            )
+        if self.mask and self.mask.value and not self.key:
+            tokens.append(
+                Key(base.TokValueLiteral(os.urandom(4)))
+            )
+        return self.__class__(
+            [i.resolve(settings, self) for i in tokens]
+        )
+
     def values(self, settings):
-        vals = []
         if self.body:
             bodygen = self.body.value.get_generator(settings)
             length = len(self.body.value.get_generator(settings))
@@ -138,29 +155,31 @@ class WebsocketFrame(message.Message):
             bodygen = None
             length = 0
         frameparts = dict(
-            mask = True,
             payload_length = length
         )
+        if self.mask and self.mask.value:
+            frameparts["mask"] = True
+        if self.key:
+            key = self.key.values(settings)[0][:]
+            frameparts["masking_key"] = key
         for i in ["opcode", "fin", "rsv1", "rsv2", "rsv3", "mask"]:
             v = getattr(self, i, None)
             if v is not None:
                 frameparts[i] = v.value
         frame = netlib.websockets.FrameHeader(**frameparts)
         vals = [frame.to_bytes()]
-        if self.body:
-            masker = netlib.websockets.Masker(frame.masking_key)
-            vals.append(
-                generators.TransformGenerator(
-                    bodygen,
-                    masker.mask
+        if bodygen:
+            if frame.masking_key:
+                masker = netlib.websockets.Masker(frame.masking_key)
+                vals.append(
+                    generators.TransformGenerator(
+                        bodygen,
+                        masker.mask
+                    )
                 )
-            )
+            else:
+                vals.append(bodygen)
         return vals
 
-    def resolve(self, settings, msg=None):
-        return self.__class__(
-            [i.resolve(settings, self) for i in self.tokens]
-        )
-
     def spec(self):
         return ":".join([i.spec() for i in self.tokens])
diff --git a/libpathod/pathoc.py b/libpathod/pathoc.py
index 2574da6c1..3d61c9e7d 100644
--- a/libpathod/pathoc.py
+++ b/libpathod/pathoc.py
@@ -212,7 +212,8 @@ class Pathoc(tcp.TCPClient):
         self.settings = language.Settings(
             staticdir = os.getcwd(),
             unconstrained_file_access = True,
-            request_host = self.address.host
+            request_host = self.address.host,
+            is_client = True
         )
         self.ssl, self.sni = ssl, sni
         self.clientcert = clientcert
diff --git a/libpathod/templates/docs_lang_websockets.html b/libpathod/templates/docs_lang_websockets.html
index c50d081f0..9eb1ec25e 100644
--- a/libpathod/templates/docs_lang_websockets.html
+++ b/libpathod/templates/docs_lang_websockets.html
@@ -44,6 +44,14 @@
             </td>
         </tr>
 
+        <tr>
+            <td> k<a href="#valuespec">VALUE</a> </td>
+            <td>
+                Set the masking key. The resulting value must be exactly 4
+                bytes long.
+            </td>
+        </tr>
+
         <tr>
             <td> [-]mask </td>
             <td>
@@ -62,8 +70,12 @@
         <tr>
             <td> r </td>
             <td>
-                Create a "raw" frame - disables auto-generation of the masking
-                key if the mask bit is on.
+                Create a "raw" frame:
+                <ul>
+                    <li> Don't auto-generate the masking key if the mask flag is
+                    set </li>
+
+                    <li> Don't set the mask flag if masking key is set. </li>
             </td>
         </tr>
 
diff --git a/test/test_language_websocket.py b/test/test_language_websocket.py
index 4b384f616..5e2ccb88f 100644
--- a/test/test_language_websocket.py
+++ b/test/test_language_websocket.py
@@ -54,17 +54,48 @@ class TestWebsocketFrame:
         assert not frm.header.rsv2
         assert not frm.header.rsv3
 
-    def test_construction(self):
-        wf = parse_request("wf:c1")
-        frm = netlib.websockets.Frame.from_bytes(tutils.render(wf))
-        assert wf.opcode.value == 1 == frm.header.opcode
+    def fr(self, spec, **kwargs):
+        settings = language.base.Settings(**kwargs)
+        wf = parse_request(spec)
+        return netlib.websockets.Frame.from_bytes(tutils.render(wf, settings))
 
-        wf = parse_request("wf:cbinary")
-        frm = netlib.websockets.Frame.from_bytes(tutils.render(wf))
-        assert wf.opcode.value == frm.header.opcode
-        assert wf.opcode.value == netlib.websockets.OPCODE.BINARY
+    def test_construction(self):
+        assert self.fr("wf:c1").header.opcode == 1
+        assert self.fr("wf:c0").header.opcode == 0
+        assert self.fr("wf:cbinary").header.opcode ==\
+            netlib.websockets.OPCODE.BINARY
+        assert self.fr("wf:ctext").header.opcode ==\
+            netlib.websockets.OPCODE.TEXT
 
     def test_auto_raw(self):
-        wf = parse_request("wf:b'foo':mask")
-        frm = netlib.websockets.Frame.from_bytes(tutils.render(wf))
-        print frm.human_readable()
+        # Simple server frame
+        frm = self.fr("wf:b'foo'")
+        assert not frm.header.mask
+        assert not frm.header.masking_key
+
+        # Simple client frame
+        frm = self.fr("wf:b'foo'", is_client=True)
+        assert frm.header.mask
+        assert frm.header.masking_key
+        frm = self.fr("wf:b'foo':k'abcd'", is_client=True)
+        assert frm.header.mask
+        assert frm.header.masking_key == 'abcd'
+
+        # Server frame, mask explicitly set
+        frm = self.fr("wf:b'foo':mask")
+        assert frm.header.mask
+        assert frm.header.masking_key
+        frm = self.fr("wf:b'foo':k'abcd'")
+        assert frm.header.mask
+        assert frm.header.masking_key == 'abcd'
+
+        # Client frame, mask explicitly unset
+        frm = self.fr("wf:b'foo':-mask", is_client=True)
+        assert not frm.header.mask
+        assert not frm.header.masking_key
+
+        frm = self.fr("wf:b'foo':-mask:k'abcd'", is_client=True)
+        assert not frm.header.mask
+        # We're reading back a corrupted frame - the first 3 characters of the
+        # mask is mis-interpreted as the payload
+        assert frm.payload == "abc"
diff --git a/test/tutils.py b/test/tutils.py
index 2387e7521..07252b537 100644
--- a/test/tutils.py
+++ b/test/tutils.py
@@ -141,6 +141,7 @@ test_data = utils.Data(__name__)
 
 
 def render(r, settings=language.Settings()):
+    r = r.resolve(settings)
     s = cStringIO.StringIO()
     assert language.serve(r, s, settings)
     return s.getvalue()