attempt to handle multiple signing requests per message and check for duplicate nonces

webserver/chocolate.py

@@ -23,6 +23,9 @@ def safe(what, s):
     """Is string s within the allowed-character policy for this field?"""
     if not isinstance(s, basestring):
         return False
+    if len(s) == 0:
+        # No validated string should be empty.
+        return False
     base64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
     csr_ok = base64 + " =-"
     if what == "nonce":
@@ -68,13 +71,14 @@ class session(object):
         return sessions.llen(self.id + ":requests") > 0
 
     def add_request(self, nonce, cn, csr):
-        if sessions.hget(self.id + ":req:" + nonce):
+        if sessions.hget(self.id + ":req:" + nonce, "cn") is not None:
             # duplicate nonce
             return False
         # TODO: is it safe to use the client-supplied nonce for naming the request?
         sessions.hset(self.id + ":req:" + nonce, "cn", cn)
         sessions.hset(self.id + ":req:" + nonce, "csr", csr)
         sessions.rpush(self.id + ":requests", nonce)
+        return True
 
 class index(object):
     def GET(self):
@@ -120,13 +124,13 @@ class index(object):
             # beginning.)
             self.die(r, r.BadRequest, uri="https://ca.example.com/failures/priorrequest")
             return
-        # TODO: currently only examine the first request, but this should be a loop.
         # TODO: check client puzzle
-        timestamp = m.request[0].timestamp
-        recipient = m.request[0].recipient
-        nonce = m.request[0].nonce
-        csr = m.request[0].csr
-        sig = m.request[0].sig
+        for i in xrange(len(m.request)):
+            timestamp = m.request[i].timestamp
+            recipient = m.request[i].recipient
+            nonce = m.request[i].nonce
+            csr = m.request[i].csr
+            sig = m.request[i].sig
             if not all([safe("recipient", recipient), safe("nonce", nonce), safe("csr", csr)]):
                 self.die(r, r.BadRequest, nonce, "https://ca.example.com/failures/illegalcharacter")
                 return
@@ -152,6 +156,7 @@ class index(object):
             if not self.session.add_request(nonce, CSR.cn(csr), csr):
                 self.die(r, r.BadRequest, nonce, "https://ca.example.com/failures/duplicatenonce")
                 return
+        # Phew!
         r.proceed.timestamp = int(time.time())
         r.proceed.polldelay = 10