acmecert

   1 #!/usr/bin/python3
   2
   3 import sys, os, getopt, binascii, json, pprint, signal, time
   4 import urllib.request
   5 import Crypto.PublicKey.RSA, Crypto.Random, Crypto.Hash.SHA256, Crypto.Signature.PKCS1_v1_5
   6
   7 service = "https://acme-v02.api.letsencrypt.org/directory"
   8 _directory = None
   9 def directory():
  10     global _directory
  11     if _directory is None:
  12         with req(service) as resp:
  13             _directory = json.loads(resp.read().decode("utf-8"))
  14     return _directory
  15
  16 def base64url(dat):
  17     return binascii.b2a_base64(dat).decode("us-ascii").translate({43: 45, 47: 95, 61: None}).strip()
  18
  19 def ebignum(num):
  20     h = "%x" % num
  21     if len(h) % 2 == 1: h = "0" + h
  22     return base64url(binascii.a2b_hex(h))
  23
  24 def getnonce():
  25     with urllib.request.urlopen(directory()["newNonce"]) as resp:
  26         resp.read()
  27         return resp.headers["Replay-Nonce"]
  28
  29 def req(url, data=None, ctype=None, headers={}, method=None, **kws):
  30     if data is not None and not isinstance(data, bytes):
  31         data = json.dumps(data).encode("utf-8")
  32         ctype = "application/jose+json"
  33     req = urllib.request.Request(url, data=data, method=method)
  34     for hnam, hval in headers.items():
  35         req.add_header(hnam, hval)
  36     if ctype is not None:
  37         req.add_header("Content-Type", ctype)
  38     return urllib.request.urlopen(req)
  39
  40 def jreq(url, data, auth):
  41     authdata = {"alg": "RS256", "url": url, "nonce": getnonce()}
  42     authdata.update(auth.authdata())
  43     authdata = base64url(json.dumps(authdata).encode("us-ascii"))
  44     if data is None:
  45         data = ""
  46     else:
  47         data = base64url(json.dumps(data).encode("us-ascii"))
  48     seal = base64url(auth.sign(("%s.%s" % (authdata, data)).encode("us-ascii")))
  49     enc = {"protected": authdata, "payload": data, "signature": seal}
  50     with req(url, data=enc) as resp:
  51         return json.loads(resp.read().decode("utf-8")), resp.headers
  52
  53 class certificate(object):
  54     @property
  55     def enddate(self):
  56         # No X509 parser for Python?
  57         import subprocess, re, calendar
  58         with subprocess.Popen(["openssl", "x509", "-noout", "-enddate"], stdin=subprocess.PIPE, stdout=subprocess.PIPE) as openssl:
  59             openssl.stdin.write(self.data.encode("us-ascii"))
  60             openssl.stdin.close()
  61             resp = openssl.stdout.read().decode("utf-8")
  62             if openssl.wait() != 0:
  63                 raise Exception("openssl error")
  64         m = re.search(r"notAfter=(.*)$", resp)
  65         if m is None: raise Exception("unexpected openssl reply: %r" % (resp,))
  66         return calendar.timegm(time.strptime(m.group(1), "%b %d %H:%M:%S %Y GMT"))
  67
  68     def expiring(self, timespec):
  69         if timespec.endswith("y"):
  70             timespec = int(timespec[:-1]) * 365 * 86400
  71         elif timespec.endswith("m"):
  72             timespec = int(timespec[:-1]) * 30 * 86400
  73         elif timespec.endswith("w"):
  74             timespec = int(timespec[:-1]) * 7 * 86400
  75         elif timespec.endswith("d"):
  76             timespec = int(timespec[:-1]) * 86400
  77         elif timespec.endswith("h"):
  78             timespec = int(timespec[:-1]) * 3600
  79         else:
  80             timespec = int(timespec)
  81         return (self.enddate - time.time()) < timespec
  82
  83     @classmethod
  84     def read(cls, fp):
  85         self = cls()
  86         self.data = fp.read()
  87         return self
  88
  89 class signreq(object):
  90     def domains(self):
  91         # No PCKS10 parser for Python?
  92         import subprocess, re
  93         with subprocess.Popen(["openssl", "req", "-noout", "-text"], stdin=subprocess.PIPE, stdout=subprocess.PIPE) as openssl:
  94             openssl.stdin.write(self.data.encode("us-ascii"))
  95             openssl.stdin.close()
  96             resp = openssl.stdout.read().decode("utf-8")
  97             if openssl.wait() != 0:
  98                 raise Exception("openssl error")
  99         m = re.search(r"X509v3 Subject Alternative Name:[^\n]*\n\s*((\w+:\S+,\s*)*\w+:\S+)\s*\n", resp)
 100         if m is None:
 101             return []
 102         ret = []
 103         for nm in m.group(1).split(","):
 104             nm = nm.strip()
 105             typ, nm = nm.split(":", 1)
 106             if typ == "DNS":
 107                 ret.append(nm)
 108         return ret
 109
 110     def der(self):
 111         import subprocess
 112         with subprocess.Popen(["openssl", "req", "-outform", "der"], stdin=subprocess.PIPE, stdout=subprocess.PIPE) as openssl:
 113             openssl.stdin.write(self.data.encode("us-ascii"))
 114             openssl.stdin.close()
 115             resp = openssl.stdout.read()
 116             if openssl.wait() != 0:
 117                 raise Exception("openssl error")
 118         return resp
 119
 120     @classmethod
 121     def read(cls, fp):
 122         self = cls()
 123         self.data = fp.read()
 124         return self
 125
 126 class jwkauth(object):
 127     def __init__(self, key):
 128         self.key = key
 129
 130     def authdata(self):
 131         return {"jwk": {"kty": "RSA", "e": ebignum(self.key.e), "n": ebignum(self.key.n)}}
 132
 133     def sign(self, data):
 134         dig = Crypto.Hash.SHA256.new()
 135         dig.update(data)
 136         return Crypto.Signature.PKCS1_v1_5.new(self.key).sign(dig)
 137
 138 class account(object):
 139     def __init__(self, uri, key):
 140         self.uri = uri
 141         self.key = key
 142
 143     def authdata(self):
 144         return {"kid": self.uri}
 145
 146     def sign(self, data):
 147         dig = Crypto.Hash.SHA256.new()
 148         dig.update(data)
 149         return Crypto.Signature.PKCS1_v1_5.new(self.key).sign(dig)
 150
 151     def getinfo(self):
 152         data, headers = jreq(self.uri, None, self)
 153         return data
 154
 155     def validate(self):
 156         data = self.getinfo()
 157         if data.get("status", "") != "valid":
 158             raise Exception("account is not valid: %s" % (data.get("status", "\"\"")))
 159
 160     def write(self, out):
 161         out.write("%s\n" % (self.uri,))
 162         out.write("%s\n" % (self.key.exportKey().decode("us-ascii"),))
 163
 164     @classmethod
 165     def read(cls, fp):
 166         uri = fp.readline()
 167         if uri == "":
 168             raise Exception("missing account URI")
 169         uri = uri.strip()
 170         key = Crypto.PublicKey.RSA.importKey(fp.read())
 171         return cls(uri, key)
 172
 173 class htconfig(object):
 174     def __init__(self):
 175         self.roots = {}
 176
 177     @classmethod
 178     def read(cls, fp):
 179         self = cls()
 180         for ln in fp:
 181             words = ln.split()
 182             if len(words) < 1 or ln[0] == '#':
 183                 continue
 184             if words[0] == "root":
 185                 self.roots[words[1]] = words[2]
 186             else:
 187                 sys.stderr.write("acmecert: warning: unknown htconfig directive: %s\n" % (words[0]))
 188         return self
 189
 190 def register(keysize=4096):
 191     key = Crypto.PublicKey.RSA.generate(keysize, Crypto.Random.new().read)
 192     # jwk = {"kty": "RSA", "e": ebignum(key.e), "n": ebignum(key.n)}
 193     # cjwk = json.dumps(jwk, separators=(',', ':'), sort_keys=True)
 194     data, headers = jreq(directory()["newAccount"], {"termsOfServiceAgreed": True}, jwkauth(key))
 195     return account(headers["Location"], key)
 196
 197 def mkorder(acct, csr):
 198     data, headers = jreq(directory()["newOrder"], {"identifiers": [{"type": "dns", "value": dn} for dn in csr.domains()]}, acct)
 199     data["acmecert.location"] = headers["Location"]
 200     return data
 201
 202 def httptoken(acct, ch):
 203     jwk = {"kty": "RSA", "e": ebignum(acct.key.e), "n": ebignum(acct.key.n)}
 204     dig = Crypto.Hash.SHA256.new()
 205     dig.update(json.dumps(jwk, separators=(',', ':'), sort_keys=True).encode("us-ascii"))
 206     khash = base64url(dig.digest())
 207     return ch["token"], ("%s.%s" % (ch["token"], khash))
 208
 209 def authorder(acct, htconf, orderid):
 210     order, headers = jreq(orderid, None, acct)
 211     valid = False
 212     tries = 0
 213     while not valid:
 214         valid = True
 215         tries += 1
 216         if tries > 5:
 217             raise Exception("challenges refuse to become valid even after 5 retries")
 218         for authuri in order["authorizations"]:
 219             auth, headers = jreq(authuri, None, acct)
 220             if auth["status"] == "valid":
 221                 continue
 222             elif auth["status"] == "pending":
 223                 pass
 224             else:
 225                 raise Exception("unknown authorization status: %s" % (auth["status"],))
 226             valid = False
 227             if auth["identifier"]["type"] != "dns":
 228                 raise Exception("unknown authorization type: %s" % (auth["identifier"]["type"],))
 229             dn = auth["identifier"]["value"]
 230             if dn not in htconf.roots:
 231                 raise Exception("no configured ht-root for domain name %s" % (dn,))
 232             for ch in auth["challenges"]:
 233                 if ch["type"] == "http-01":
 234                     break
 235             else:
 236                 raise Exception("no http-01 challenge for %s" % (dn,))
 237             root = htconf.roots[dn]
 238             tokid, tokval = httptoken(acct, ch)
 239             tokpath = os.path.join(root, tokid);
 240             fp = open(tokpath, "w")
 241             try:
 242                 with fp:
 243                     fp.write(tokval)
 244                 with req("http://%s/.well-known/acme-challenge/%s" % (dn, tokid)) as resp:
 245                     if resp.read().decode("utf-8") != tokval:
 246                         raise Exception("challenge from %s does not match written value" % (dn,))
 247                 for n in range(30):
 248                     resp, headers = jreq(ch["url"], {}, acct)
 249                     if resp["status"] == "processing":
 250                         time.sleep(2)
 251                     elif resp["status"] == "valid":
 252                         break
 253                     else:
 254                         raise Exception("unexpected challenge status for %s when validating: %s" % (dn, resp["status"]))
 255                 else:
 256                     raise Exception("challenge processing timed out for %s" % (dn,))
 257             finally:
 258                 os.unlink(tokpath)
 259
 260 def finalize(acct, csr, orderid):
 261     order, headers = jreq(orderid, None, acct)
 262     if order["status"] == "valid":
 263         pass
 264     elif order["status"] == "ready":
 265         jreq(order["finalize"], {"csr": base64url(csr.der())}, acct)
 266         for n in range(30):
 267             resp, headers = jreq(orderid, None, acct)
 268             if resp["status"] == "processing":
 269                 time.sleep(2)
 270             elif resp["status"] == "valid":
 271                 order = resp
 272                 break
 273             else:
 274                 raise Exception("unexpected order status when finalizing: %s" % resp["status"])
 275         else:
 276             raise Exception("order finalization timed out")
 277     else:
 278         raise Exception("unexpected order state when finalizing: %s" % (order["status"],))
 279     with req(order["certificate"]) as resp:
 280         return resp.read().decode("us-ascii")
 281
 282 def usage(out):
 283     out.write("usage: acmecert [-h] [-D SERVICE]\n")
 284
 285 def main(argv):
 286     global service
 287     opts, args = getopt.getopt(argv[1:], "hD:")
 288     for o, a in opts:
 289         if o == "-h":
 290             usage(sys.stdout)
 291             sys.exit(0)
 292         elif o == "-D":
 293             service = a
 294     if len(args) < 1:
 295         usage(sys.stderr)
 296         sys.exit(1)
 297     if args[0] == "reg":
 298         register().write(sys.stdout)
 299     elif args[0] == "validate-acct":
 300         with open(args[1], "r") as fp:
 301             account.read(fp).validate()
 302     elif args[0] == "acctinfo":
 303         with open(args[1], "r") as fp:
 304             pprint.pprint(account.read(fp).getinfo())
 305     elif args[0] == "order":
 306         with open(args[1], "r") as fp:
 307             acct = account.read(fp)
 308         with open(args[2], "r") as fp:
 309             csr = signreq.read(fp)
 310         order = mkorder(acct, csr)
 311         with open(args[3], "w") as fp:
 312             fp.write("%s\n" % (order["acmecert.location"]))
 313     elif args[0] == "http-auth":
 314         with open(args[1], "r") as fp:
 315             acct = account.read(fp)
 316         with open(args[2], "r") as fp:
 317             htconf = htconfig.read(fp)
 318         with open(args[3], "r") as fp:
 319             orderid = fp.readline().strip()
 320         authorder(acct, htconf, orderid)
 321     elif args[0] == "get":
 322         with open(args[1], "r") as fp:
 323             acct = account.read(fp)
 324         with open(args[2], "r") as fp:
 325             csr = signreq.read(fp)
 326         with open(args[3], "r") as fp:
 327             orderid = fp.readline().strip()
 328         sys.stdout.write(finalize(acct, csr, orderid))
 329     elif args[0] == "http-order":
 330         with open(args[1], "r") as fp:
 331             acct = account.read(fp)
 332         with open(args[2], "r") as fp:
 333             csr = signreq.read(fp)
 334         with open(args[3], "r") as fp:
 335             htconf = htconfig.read(fp)
 336         orderid = mkorder(acct, csr)["acmecert.location"]
 337         authorder(acct, htconf, orderid)
 338         sys.stdout.write(finalize(acct, csr, orderid))
 339     elif args[0] == "check-cert":
 340         with open(args[1], "r") as fp:
 341             crt = certificate.read(fp)
 342         sys.exit(1 if crt.expiring(args[2]) else 0)
 343     elif args[0] == "directory":
 344         pprint.pprint(directory())
 345     else:
 346         sys.stderr.write("acmecert: unknown command: %s\n" % (args[0],))
 347         usage(sys.stderr)
 348         sys.exit(1)
 349
 350 if __name__ == "__main__":
 351     try:
 352         main(sys.argv)
 353     except KeyboardInterrupt:
 354         signal.signal(signal.SIGINT, signal.SIG_DFL)
 355         os.kill(os.getpid(), signal.SIGINT)