src/allmydata/introducer/common.py

   1
   2 import re, simplejson
   3 from allmydata.util import keyutil, base32
   4
   5 def make_index(ann, key_s):
   6     """Return something that can be used as an index (e.g. a tuple of
   7     strings), such that two messages that refer to the same 'thing' will have
   8     the same index. This is a tuple of (service-name, signing-key, None) for
   9     signed announcements, or (service-name, None, tubid) for unsigned
  10     announcements."""
  11
  12     service_name = str(ann["service-name"])
  13     if key_s:
  14         return (service_name, key_s, None)
  15     else:
  16         tubid = get_tubid_string_from_ann(ann)
  17         return (service_name, None, tubid)
  18
  19 def get_tubid_string_from_ann(ann):
  20     return get_tubid_string(str(ann.get("anonymous-storage-FURL")
  21                                 or ann.get("FURL")))
  22
  23 def get_tubid_string(furl):
  24     m = re.match(r'pb://(\w+)@', furl)
  25     assert m
  26     return m.group(1).lower()
  27
  28 def convert_announcement_v1_to_v2(ann_t):
  29     (furl, service_name, ri_name, nickname, ver, oldest) = ann_t
  30     assert type(furl) is str
  31     assert type(service_name) is str
  32     # ignore ri_name
  33     assert type(nickname) is str
  34     assert type(ver) is str
  35     assert type(oldest) is str
  36     ann = {"version": 0,
  37            "nickname": nickname.decode("utf-8"),
  38            "app-versions": {},
  39            "my-version": ver,
  40            "oldest-supported": oldest,
  41
  42            "service-name": service_name,
  43            "anonymous-storage-FURL": furl,
  44            "permutation-seed-base32": get_tubid_string(furl),
  45            }
  46     msg = simplejson.dumps(ann).encode("utf-8")
  47     return (msg, None, None)
  48
  49 def convert_announcement_v2_to_v1(ann_v2):
  50     (msg, sig, pubkey) = ann_v2
  51     ann = simplejson.loads(msg)
  52     assert ann["version"] == 0
  53     ann_t = (str(ann["anonymous-storage-FURL"]),
  54              str(ann["service-name"]),
  55              "remoteinterface-name is unused",
  56              ann["nickname"].encode("utf-8"),
  57              str(ann["my-version"]),
  58              str(ann["oldest-supported"]),
  59              )
  60     return ann_t
  61
  62
  63 def sign_to_foolscap(ann, sk):
  64     # return (bytes, None, None) or (bytes, sig-str, pubkey-str). A future
  65     # HTTP-based serialization will use JSON({msg:b64(JSON(msg).utf8),
  66     # sig:v0-b64(sig), pubkey:v0-b64(pubkey)}) .
  67     msg = simplejson.dumps(ann).encode("utf-8")
  68     if sk:
  69         sig = "v0-"+base32.b2a(sk.sign(msg))
  70         vk_bytes = sk.get_verifying_key_bytes()
  71         ann_t = (msg, sig, "v0-"+base32.b2a(vk_bytes))
  72     else:
  73         ann_t = (msg, None, None)
  74     return ann_t
  75
  76 class UnknownKeyError(Exception):
  77     pass
  78
  79 def unsign_from_foolscap(ann_t):
  80     (msg, sig_vs, claimed_key_vs) = ann_t
  81     key_vs = None
  82     if sig_vs and claimed_key_vs:
  83         if not sig_vs.startswith("v0-"):
  84             raise UnknownKeyError("only v0- signatures recognized")
  85         if not claimed_key_vs.startswith("v0-"):
  86             raise UnknownKeyError("only v0- keys recognized")
  87         claimed_key = keyutil.parse_pubkey("pub-"+claimed_key_vs)
  88         sig_bytes = base32.a2b(keyutil.remove_prefix(sig_vs, "v0-"))
  89         claimed_key.verify(sig_bytes, msg)
  90         key_vs = claimed_key_vs
  91     ann = simplejson.loads(msg.decode("utf-8"))
  92     return (ann, key_vs)