acmecert

   1 #!/usr/bin/python3
   2
   3 import sys, os, getopt, binascii, json, pprint, signal, time, threading
   4 import urllib.request
   5 import Crypto.PublicKey.RSA, Crypto.Random, Crypto.Hash.SHA256, Crypto.Signature.PKCS1_v1_5
   6
   7 class msgerror(Exception):
   8     def report(self, out):
   9         out.write("acmecert: undefined error\n")
  10
  11 service = "https://acme-v02.api.letsencrypt.org/directory"
  12 _directory = None
  13 def directory():
  14     global _directory
  15     if _directory is None:
  16         with req(service) as resp:
  17             _directory = json.loads(resp.read().decode("utf-8"))
  18     return _directory
  19
  20 def base64url(dat):
  21     return binascii.b2a_base64(dat).decode("us-ascii").translate({43: 45, 47: 95, 61: None}).strip()
  22
  23 def ebignum(num):
  24     h = "%x" % num
  25     if len(h) % 2 == 1: h = "0" + h
  26     return base64url(binascii.a2b_hex(h))
  27
  28 def getnonce():
  29     with urllib.request.urlopen(directory()["newNonce"]) as resp:
  30         resp.read()
  31         return resp.headers["Replay-Nonce"]
  32
  33 def req(url, data=None, ctype=None, headers={}, method=None, **kws):
  34     if data is not None and not isinstance(data, bytes):
  35         data = json.dumps(data).encode("utf-8")
  36         ctype = "application/jose+json"
  37     req = urllib.request.Request(url, data=data, method=method)
  38     for hnam, hval in headers.items():
  39         req.add_header(hnam, hval)
  40     if ctype is not None:
  41         req.add_header("Content-Type", ctype)
  42     return urllib.request.urlopen(req)
  43
  44 def jreq(url, data, auth):
  45     authdata = {"alg": "RS256", "url": url, "nonce": getnonce()}
  46     authdata.update(auth.authdata())
  47     authdata = base64url(json.dumps(authdata).encode("us-ascii"))
  48     if data is None:
  49         data = ""
  50     else:
  51         data = base64url(json.dumps(data).encode("us-ascii"))
  52     seal = base64url(auth.sign(("%s.%s" % (authdata, data)).encode("us-ascii")))
  53     enc = {"protected": authdata, "payload": data, "signature": seal}
  54     with req(url, data=enc) as resp:
  55         return json.loads(resp.read().decode("utf-8")), resp.headers
  56
  57 class certificate(object):
  58     @property
  59     def enddate(self):
  60         # No X509 parser for Python?
  61         import subprocess, re, calendar
  62         with subprocess.Popen(["openssl", "x509", "-noout", "-enddate"], stdin=subprocess.PIPE, stdout=subprocess.PIPE) as openssl:
  63             openssl.stdin.write(self.data.encode("us-ascii"))
  64             openssl.stdin.close()
  65             resp = openssl.stdout.read().decode("utf-8")
  66             if openssl.wait() != 0:
  67                 raise Exception("openssl error")
  68         m = re.search(r"notAfter=(.*)$", resp)
  69         if m is None: raise Exception("unexpected openssl reply: %r" % (resp,))
  70         return calendar.timegm(time.strptime(m.group(1), "%b %d %H:%M:%S %Y GMT"))
  71
  72     def expiring(self, timespec):
  73         if timespec.endswith("y"):
  74             timespec = int(timespec[:-1]) * 365 * 86400
  75         elif timespec.endswith("m"):
  76             timespec = int(timespec[:-1]) * 30 * 86400
  77         elif timespec.endswith("w"):
  78             timespec = int(timespec[:-1]) * 7 * 86400
  79         elif timespec.endswith("d"):
  80             timespec = int(timespec[:-1]) * 86400
  81         elif timespec.endswith("h"):
  82             timespec = int(timespec[:-1]) * 3600
  83         else:
  84             timespec = int(timespec)
  85         return (self.enddate - time.time()) < timespec
  86
  87     @classmethod
  88     def read(cls, fp):
  89         self = cls()
  90         self.data = fp.read()
  91         return self
  92
  93 class signreq(object):
  94     def domains(self):
  95         # No PCKS10 parser for Python?
  96         import subprocess, re
  97         with subprocess.Popen(["openssl", "req", "-noout", "-text"], stdin=subprocess.PIPE, stdout=subprocess.PIPE) as openssl:
  98             openssl.stdin.write(self.data.encode("us-ascii"))
  99             openssl.stdin.close()
 100             resp = openssl.stdout.read().decode("utf-8")
 101             if openssl.wait() != 0:
 102                 raise Exception("openssl error")
 103         m = re.search(r"X509v3 Subject Alternative Name:[^\n]*\n\s*((\w+:\S+,\s*)*\w+:\S+)\s*\n", resp)
 104         if m is None:
 105             return []
 106         ret = []
 107         for nm in m.group(1).split(","):
 108             nm = nm.strip()
 109             typ, nm = nm.split(":", 1)
 110             if typ == "DNS":
 111                 ret.append(nm)
 112         return ret
 113
 114     def der(self):
 115         import subprocess
 116         with subprocess.Popen(["openssl", "req", "-outform", "der"], stdin=subprocess.PIPE, stdout=subprocess.PIPE) as openssl:
 117             openssl.stdin.write(self.data.encode("us-ascii"))
 118             openssl.stdin.close()
 119             resp = openssl.stdout.read()
 120             if openssl.wait() != 0:
 121                 raise Exception("openssl error")
 122         return resp
 123
 124     @classmethod
 125     def read(cls, fp):
 126         self = cls()
 127         self.data = fp.read()
 128         return self
 129
 130 class jwkauth(object):
 131     def __init__(self, key):
 132         self.key = key
 133
 134     def authdata(self):
 135         return {"jwk": {"kty": "RSA", "e": ebignum(self.key.e), "n": ebignum(self.key.n)}}
 136
 137     def sign(self, data):
 138         dig = Crypto.Hash.SHA256.new()
 139         dig.update(data)
 140         return Crypto.Signature.PKCS1_v1_5.new(self.key).sign(dig)
 141
 142 class account(object):
 143     def __init__(self, uri, key):
 144         self.uri = uri
 145         self.key = key
 146
 147     def authdata(self):
 148         return {"kid": self.uri}
 149
 150     def sign(self, data):
 151         dig = Crypto.Hash.SHA256.new()
 152         dig.update(data)
 153         return Crypto.Signature.PKCS1_v1_5.new(self.key).sign(dig)
 154
 155     def getinfo(self):
 156         data, headers = jreq(self.uri, None, self)
 157         return data
 158
 159     def validate(self):
 160         data = self.getinfo()
 161         if data.get("status", "") != "valid":
 162             raise Exception("account is not valid: %s" % (data.get("status", "\"\"")))
 163
 164     def write(self, out):
 165         out.write("%s\n" % (self.uri,))
 166         out.write("%s\n" % (self.key.exportKey().decode("us-ascii"),))
 167
 168     @classmethod
 169     def read(cls, fp):
 170         uri = fp.readline()
 171         if uri == "":
 172             raise Exception("missing account URI")
 173         uri = uri.strip()
 174         key = Crypto.PublicKey.RSA.importKey(fp.read())
 175         return cls(uri, key)
 176
 177 class htconfig(object):
 178     def __init__(self):
 179         self.roots = {}
 180
 181     @classmethod
 182     def read(cls, fp):
 183         self = cls()
 184         for ln in fp:
 185             words = ln.split()
 186             if len(words) < 1 or ln[0] == '#':
 187                 continue
 188             if words[0] == "root":
 189                 self.roots[words[1]] = words[2]
 190             else:
 191                 sys.stderr.write("acmecert: warning: unknown htconfig directive: %s\n" % (words[0]))
 192         return self
 193
 194 def register(keysize=4096):
 195     key = Crypto.PublicKey.RSA.generate(keysize, Crypto.Random.new().read)
 196     data, headers = jreq(directory()["newAccount"], {"termsOfServiceAgreed": True}, jwkauth(key))
 197     return account(headers["Location"], key)
 198
 199 def mkorder(acct, csr):
 200     data, headers = jreq(directory()["newOrder"], {"identifiers": [{"type": "dns", "value": dn} for dn in csr.domains()]}, acct)
 201     data["acmecert.location"] = headers["Location"]
 202     return data
 203
 204 def httptoken(acct, ch):
 205     jwk = {"kty": "RSA", "e": ebignum(acct.key.e), "n": ebignum(acct.key.n)}
 206     dig = Crypto.Hash.SHA256.new()
 207     dig.update(json.dumps(jwk, separators=(',', ':'), sort_keys=True).encode("us-ascii"))
 208     khash = base64url(dig.digest())
 209     return ch["token"], ("%s.%s" % (ch["token"], khash))
 210
 211 def authorder(acct, htconf, orderid):
 212     order, headers = jreq(orderid, None, acct)
 213     valid = False
 214     tries = 0
 215     while not valid:
 216         valid = True
 217         tries += 1
 218         if tries > 5:
 219             raise Exception("challenges refuse to become valid even after 5 retries")
 220         for authuri in order["authorizations"]:
 221             auth, headers = jreq(authuri, None, acct)
 222             if auth["status"] == "valid":
 223                 continue
 224             elif auth["status"] == "pending":
 225                 pass
 226             else:
 227                 raise Exception("unknown authorization status: %s" % (auth["status"],))
 228             valid = False
 229             if auth["identifier"]["type"] != "dns":
 230                 raise Exception("unknown authorization type: %s" % (auth["identifier"]["type"],))
 231             dn = auth["identifier"]["value"]
 232             if dn not in htconf.roots:
 233                 raise Exception("no configured ht-root for domain name %s" % (dn,))
 234             for ch in auth["challenges"]:
 235                 if ch["type"] == "http-01":
 236                     break
 237             else:
 238                 raise Exception("no http-01 challenge for %s" % (dn,))
 239             root = htconf.roots[dn]
 240             tokid, tokval = httptoken(acct, ch)
 241             tokpath = os.path.join(root, tokid);
 242             fp = open(tokpath, "w")
 243             try:
 244                 with fp:
 245                     fp.write(tokval)
 246                 with req("http://%s/.well-known/acme-challenge/%s" % (dn, tokid)) as resp:
 247                     if resp.read().decode("utf-8") != tokval:
 248                         raise Exception("challenge from %s does not match written value" % (dn,))
 249                 for n in range(30):
 250                     resp, headers = jreq(ch["url"], {}, acct)
 251                     if resp["status"] == "processing":
 252                         time.sleep(2)
 253                     elif resp["status"] == "pending":
 254                         # I don't think this should happen, but it
 255                         # does. LE bug? Anyway, just retry.
 256                         if n < 5:
 257                             time.sleep(2)
 258                         else:
 259                             break
 260                     elif resp["status"] == "valid":
 261                         break
 262                     else:
 263                         raise Exception("unexpected challenge status for %s when validating: %s" % (dn, resp["status"]))
 264                 else:
 265                     raise Exception("challenge processing timed out for %s" % (dn,))
 266             finally:
 267                 os.unlink(tokpath)
 268
 269 def finalize(acct, csr, orderid):
 270     order, headers = jreq(orderid, None, acct)
 271     if order["status"] == "valid":
 272         pass
 273     elif order["status"] == "ready":
 274         jreq(order["finalize"], {"csr": base64url(csr.der())}, acct)
 275         for n in range(30):
 276             resp, headers = jreq(orderid, None, acct)
 277             if resp["status"] == "processing":
 278                 time.sleep(2)
 279             elif resp["status"] == "valid":
 280                 order = resp
 281                 break
 282             else:
 283                 raise Exception("unexpected order status when finalizing: %s" % resp["status"])
 284         else:
 285             raise Exception("order finalization timed out")
 286     else:
 287         raise Exception("unexpected order state when finalizing: %s" % (order["status"],))
 288     with req(order["certificate"]) as resp:
 289         return resp.read().decode("us-ascii")
 290
 291 class maybeopen(object):
 292     def __init__(self, name, mode):
 293         if name == "-":
 294             self.opened = False
 295             if mode == "r":
 296                 self.fp = sys.stdin
 297             elif mode == "w":
 298                 self.fp = sys.stdout
 299             else:
 300                 raise ValueError(mode)
 301         else:
 302             self.opened = True
 303             self.fp = open(name, mode)
 304
 305     def __enter__(self):
 306         return self.fp
 307
 308     def __exit__(self, *excinfo):
 309         if self.opened:
 310             self.fp.close()
 311         return False
 312
 313 invdata = threading.local()
 314 commands = {}
 315
 316 class usageerr(msgerror):
 317     def __init__(self):
 318         self.cmd = invdata.cmd
 319
 320     def report(self, out):
 321         out.write("%s\n" % (self.cmd.__doc__,))
 322
 323 def cmd_reg(args):
 324     "usage: acmecert reg [OUTPUT-FILE]"
 325     acct = register()
 326     os.umask(0o077)
 327     with maybeopen(args[1] if len(args) > 1 else "-", "w") as fp:
 328         acct.write(fp)
 329 commands["reg"] = cmd_reg
 330
 331 def cmd_validate_acct(args):
 332     "usage: acmecert validate-acct ACCOUNT-FILE"
 333     if len(args) < 2: raise usageerr()
 334     with maybeopen(args[1], "r") as fp:
 335         account.read(fp).validate()
 336 commands["validate-acct"] = cmd_validate_acct
 337
 338 def cmd_acct_info(args):
 339     "usage: acmecert acct-info ACCOUNT-FILE"
 340     if len(args) < 2: raise usageerr()
 341     with maybeopen(args[1], "r") as fp:
 342         pprint.pprint(account.read(fp).getinfo())
 343 commands["acct-info"] = cmd_acct_info
 344
 345 def cmd_order(args):
 346     "usage: acmecert order ACCOUNT-FILE CSR [OUTPUT-FILE]"
 347     if len(args) < 3: raise usageerr()
 348     with maybeopen(args[1], "r") as fp:
 349         acct = account.read(fp)
 350     with maybeopen(args[2], "r") as fp:
 351         csr = signreq.read(fp)
 352     order = mkorder(acct, csr)
 353     with maybeopen(args[3] if len(args) > 3 else "-", "w") as fp:
 354         fp.write("%s\n" % (order["acmecert.location"]))
 355 commands["order"] = cmd_order
 356
 357 def cmd_http_auth(args):
 358     "usage: acmecert http-auth ACCOUNT-FILE HTTP-CONFIG {ORDER-ID|ORDER-FILE}"
 359     if len(args) < 4: raise usageerr()
 360     with maybeopen(args[1], "r") as fp:
 361         acct = account.read(fp)
 362     with maybeopen(args[2], "r") as fp:
 363         htconf = htconfig.read(fp)
 364     if "://" in args[3]:
 365         orderid = args[3]
 366     else:
 367         with maybeopen(args[3], "r") as fp:
 368             orderid = fp.readline().strip()
 369     authorder(acct, htconf, orderid)
 370 commands["http-auth"] = cmd_http_auth
 371
 372 def cmd_get(args):
 373     "usage: acmecert get ACCOUNT-FILE CSR {ORDER-ID|ORDER-FILE}"
 374     if len(args) < 4: raise usageerr()
 375     with maybeopen(args[1], "r") as fp:
 376         acct = account.read(fp)
 377     with maybeopen(args[2], "r") as fp:
 378         csr = signreq.read(fp)
 379     if "://" in args[3]:
 380         orderid = args[3]
 381     else:
 382         with maybeopen(args[3], "r") as fp:
 383             orderid = fp.readline().strip()
 384     sys.stdout.write(finalize(acct, csr, orderid))
 385 commands["get"] = cmd_get
 386
 387 def cmd_http_order(args):
 388     "usage: acmecert http-order ACCOUNT-FILE CSR HTTP-CONFIG [OUTPUT-FILE]"
 389     if len(args) < 4: raise usageerr()
 390     with maybeopen(args[1], "r") as fp:
 391         acct = account.read(fp)
 392     with maybeopen(args[2], "r") as fp:
 393         csr = signreq.read(fp)
 394     with maybeopen(args[3], "r") as fp:
 395         htconf = htconfig.read(fp)
 396     orderid = mkorder(acct, csr)["acmecert.location"]
 397     authorder(acct, htconf, orderid)
 398     with maybeopen(args[4] if len(args) > 4 else "-", "w") as fp:
 399         fp.write(finalize(acct, csr, orderid))
 400 commands["http-order"] = cmd_http_order
 401
 402 def cmd_check_cert(args):
 403     "usage: acmecert check-cert CERT-FILE TIME-SPEC"
 404     if len(args) < 3: raise usageerr()
 405     with maybeopen(args[1], "r") as fp:
 406         crt = certificate.read(fp)
 407     sys.exit(1 if crt.expiring(args[2]) else 0)
 408 commands["check-cert"] = cmd_check_cert
 409
 410 def cmd_directory(args):
 411     "usage: acmecert directory"
 412     pprint.pprint(directory())
 413 commands["directory"] = cmd_directory
 414
 415 def usage(out):
 416     out.write("usage: acmecert [-D SERVICE] COMMAND [ARGS...]\n")
 417     out.write("       acmecert -h [COMMAND]\n")
 418     buf =     "       COMMAND is any of: "
 419     f = True
 420     for cmd in commands:
 421         if len(buf) + len(cmd) > 70:
 422             out.write("%s\n" % (buf,))
 423             buf =     "           "
 424             f = True
 425         if not f:
 426             buf += ", "
 427         buf += cmd
 428         f = False
 429     if not f:
 430         out.write("%s\n" % (buf,))
 431
 432 def main(argv):
 433     global service
 434     opts, args = getopt.getopt(argv[1:], "hD:")
 435     for o, a in opts:
 436         if o == "-h":
 437             if len(args) > 0:
 438                 cmd = commands.get(args[0])
 439                 if cmd is None:
 440                     sys.stderr.write("acmecert: unknown command: %s\n" % (args[0],))
 441                     sys.exit(1)
 442                 sys.stdout.write("%s\n" % (cmd.__doc__,))
 443             else:
 444                 usage(sys.stdout)
 445             sys.exit(0)
 446         elif o == "-D":
 447             service = a
 448     if len(args) < 1:
 449         usage(sys.stderr)
 450         sys.exit(1)
 451     cmd = commands.get(args[0])
 452     if cmd is None:
 453         sys.stderr.write("acmecert: unknown command: %s\n" % (args[0],))
 454         usage(sys.stderr)
 455         sys.exit(1)
 456     try:
 457         try:
 458             invdata.cmd = cmd
 459             cmd(args)
 460         finally:
 461             invdata.cmd = None
 462     except msgerror as exc:
 463         exc.report(sys.stderr)
 464         sys.exit(1)
 465
 466 if __name__ == "__main__":
 467     try:
 468         main(sys.argv)
 469     except KeyboardInterrupt:
 470         signal.signal(signal.SIGINT, signal.SIG_DFL)
 471         os.kill(os.getpid(), signal.SIGINT)