Fix typo.
[wrw.git] / wrw / auth.py
CommitLineData
ecbfa279 1import binascii, hashlib, threading, time
6d2e09cf 2from . import resp
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3
4class unauthorized(resp.httperror):
5 def __init__(self, challenge, message=None, detail=None):
6d2e09cf 6 super().__init__(401, message, detail)
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7 if isinstance(challenge, str):
8 challenge = [challenge]
9 self.challenge = challenge
10
11 def handle(self, req):
12 for challenge in self.challenge:
13 req.ohead.add("WWW-Authenticate", challenge)
6d2e09cf 14 return super().handle(req)
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15
16class forbidden(resp.httperror):
17 def __init__(self, message=None, detail=None):
6d2e09cf 18 super().__init__(403, message, detail)
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19
20def parsemech(req):
21 h = req.ihead.get("Authorization", None)
22 if h is None:
23 return None, None
24 p = h.find(" ")
25 if p < 0:
26 return None, None
27 return h[:p].strip().lower(), h[p + 1:].strip()
28
29def parsebasic(req):
30 mech, data = parsemech(req)
31 if mech != "basic":
32 return None, None
33 try:
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34 data = data.encode("us-ascii")
35 except UnicodeError:
36 return None, None
37 try:
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38 raw = binascii.a2b_base64(data)
39 except binascii.Error:
40 return None, None
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41 try:
42 raw = raw.decode("utf-8")
43 except UnicodeError:
44 raw = raw.decode("latin1")
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45 p = raw.find(":")
46 if p < 0:
47 return None, None
48 return raw[:p], raw[p + 1:]
49
50class basiccache(object):
51 cachetime = 300
52
53 def __init__(self, realm, authfn=None):
54 self._lock = threading.Lock()
55 self._cache = {}
56 self.realm = realm
57 if authfn is not None:
58 self.auth = authfn
59
60 def _obscure(self, nm, pw):
61 dig = hashlib.sha256()
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62 dig.update(self.realm.encode("utf-8"))
63 dig.update(nm.encode("utf-8"))
64 dig.update(pw.encode("utf-8"))
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65 return dig.digest()
66
67 def check(self, req):
68 nm, pw = parsebasic(req)
69 if nm is None:
70 raise unauthorized("Basic Realm=\"%s\"" % self.realm)
71 pwh = self._obscure(nm, pw)
72 now = time.time()
73 with self._lock:
74 if (nm, pwh) in self._cache:
75 lock, atime, res, resob = self._cache[nm, pwh]
76 if now - atime < self.cachetime:
77 if res == "s":
78 return resob
79 elif res == "f":
80 raise resob
81 else:
82 lock = threading.Lock()
83 self._cache[nm, pwh] = (lock, now, None, None)
84 with lock:
85 try:
86 ret = self.auth(req, nm, pw)
6d2e09cf 87 except forbidden as exc:
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88 with self._lock:
89 self._cache[nm, pwh] = (lock, now, "f", exc)
90 raise
91 if ret is None:
92 raise forbidden()
93 with self._lock:
94 self._cache[nm, pwh] = (lock, now, "s", ret)
95 return ret
96
97 def auth(self, req, nm, pw):
98 raise Exception("authentication function neither supplied nor overridden")