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"] == "pending":
 252                         # I don't think this should happen, but it
 253                         # does. LE bug? Anyway, just retry.
 254                         break
 255                     elif resp["status"] == "valid":
 256                         break
 257                     else:
 258                         raise Exception("unexpected challenge status for %s when validating: %s" % (dn, resp["status"]))
 259                 else:
 260                     raise Exception("challenge processing timed out for %s" % (dn,))
 261             finally:
 262                 os.unlink(tokpath)
 263
 264 def finalize(acct, csr, orderid):
 265     order, headers = jreq(orderid, None, acct)
 266     if order["status"] == "valid":
 267         pass
 268     elif order["status"] == "ready":
 269         jreq(order["finalize"], {"csr": base64url(csr.der())}, acct)
 270         for n in range(30):
 271             resp, headers = jreq(orderid, None, acct)
 272             if resp["status"] == "processing":
 273                 time.sleep(2)
 274             elif resp["status"] == "valid":
 275                 order = resp
 276                 break
 277             else:
 278                 raise Exception("unexpected order status when finalizing: %s" % resp["status"])
 279         else:
 280             raise Exception("order finalization timed out")
 281     else:
 282         raise Exception("unexpected order state when finalizing: %s" % (order["status"],))
 283     with req(order["certificate"]) as resp:
 284         return resp.read().decode("us-ascii")
 285
 286 class maybeopen(object):
 287     def __init__(self, name, mode):
 288         if name == "-":
 289             self.opened = False
 290             if mode == "r":
 291                 self.fp = sys.stdin
 292             elif mode == "w":
 293                 self.fp = sys.stdout
 294             else:
 295                 raise ValueError(mode)
 296         else:
 297             self.opened = True
 298             self.fp = open(name, mode)
 299
 300     def __enter__(self):
 301         return self.fp
 302
 303     def __exit__(self, *excinfo):
 304         if self.opened:
 305             self.fp.close()
 306         return False
 307
 308 class usageerr(Exception):
 309     pass
 310
 311 commands = {}
 312
 313 def cmd_reg(args):
 314     "usage: acmecert reg [OUTPUT-FILE]"
 315     acct = register()
 316     os.umask(0o077)
 317     with maybeopen(args[1] if len(args) > 1 else "-", "w") as fp:
 318         acct.write(fp)
 319 commands["reg"] = cmd_reg
 320
 321 def cmd_validate_acct(args):
 322     "usage: acmecert validate-acct ACCOUNT-FILE"
 323     if len(args) < 2: raise usageerr()
 324     with maybeopen(args[1], "r") as fp:
 325         account.read(fp).validate()
 326 commands["validate-acct"] = cmd_validate_acct
 327
 328 def cmd_acct_info(args):
 329     "usage: acmecert acct-info ACCOUNT-FILE"
 330     if len(args) < 2: raise usageerr()
 331     with maybeopen(args[1], "r") as fp:
 332         pprint.pprint(account.read(fp).getinfo())
 333 commands["acct-info"] = cmd_acct_info
 334
 335 def cmd_order(args):
 336     "usage: acmecert order ACCOUNT-FILE CSR [OUTPUT-FILE]"
 337     if len(args) < 3: raise usageerr()
 338     with maybeopen(args[1], "r") as fp:
 339         acct = account.read(fp)
 340     with maybeopen(args[2], "r") as fp:
 341         csr = signreq.read(fp)
 342     order = mkorder(acct, csr)
 343     with maybeopen(args[3] if len(args) > 3 else "-", "w") as fp:
 344         fp.write("%s\n" % (order["acmecert.location"]))
 345 commands["order"] = cmd_order
 346
 347 def cmd_http_auth(args):
 348     "usage: acmecert http-auth ACCOUNT-FILE HTTP-CONFIG {ORDER-ID|ORDER-FILE}"
 349     if len(args) < 4: raise usageerr()
 350     with maybeopen(args[1], "r") as fp:
 351         acct = account.read(fp)
 352     with maybeopen(args[2], "r") as fp:
 353         htconf = htconfig.read(fp)
 354     if "://" in args[3]:
 355         orderid = args[3]
 356     else:
 357         with maybeopen(args[3], "r") as fp:
 358             orderid = fp.readline().strip()
 359     authorder(acct, htconf, orderid)
 360 commands["http-auth"] = cmd_http_auth
 361
 362 def cmd_get(args):
 363     "usage: acmecert get ACCOUNT-FILE CSR {ORDER-ID|ORDER-FILE}"
 364     if len(args) < 4: raise usageerr()
 365     with maybeopen(args[1], "r") as fp:
 366         acct = account.read(fp)
 367     with maybeopen(args[2], "r") as fp:
 368         csr = signreq.read(fp)
 369     if "://" in args[3]:
 370         orderid = args[3]
 371     else:
 372         with maybeopen(args[3], "r") as fp:
 373             orderid = fp.readline().strip()
 374     sys.stdout.write(finalize(acct, csr, orderid))
 375 commands["get"] = cmd_get
 376
 377 def cmd_http_order(args):
 378     "usage: acmecert http-order ACCOUNT-FILE CSR HTTP-CONFIG [OUTPUT-FILE]"
 379     if len(args) < 4: raise usageerr()
 380     with maybeopen(args[1], "r") as fp:
 381         acct = account.read(fp)
 382     with maybeopen(args[2], "r") as fp:
 383         csr = signreq.read(fp)
 384     with maybeopen(args[3], "r") as fp:
 385         htconf = htconfig.read(fp)
 386     orderid = mkorder(acct, csr)["acmecert.location"]
 387     authorder(acct, htconf, orderid)
 388     with maybeopen(args[4] if len(args) > 4 else "-", "w") as fp:
 389         fp.write(finalize(acct, csr, orderid))
 390 commands["http-order"] = cmd_http_order
 391
 392 def cmd_check_cert(args):
 393     "usage: acmecert check-cert CERT-FILE TIME-SPEC"
 394     if len(args) < 3: raise usageerr()
 395     with maybeopen(args[1], "r") as fp:
 396         crt = certificate.read(fp)
 397     sys.exit(1 if crt.expiring(args[2]) else 0)
 398 commands["check-cert"] = cmd_check_cert
 399
 400 def cmd_directory(args):
 401     "usage: acmecert directory"
 402     pprint.pprint(directory())
 403 commands["directory"] = cmd_directory
 404
 405 def usage(out):
 406     out.write("usage: acmecert [-D SERVICE] COMMAND [ARGS...]\n")
 407     out.write("       acmecert -h [COMMAND]\n")
 408     buf =     "       COMMAND is any of: "
 409     f = True
 410     for cmd in commands:
 411         if len(buf) + len(cmd) > 70:
 412             out.write("%s\n" % (buf,))
 413             buf =     "           "
 414             f = True
 415         if not f:
 416             buf += ", "
 417         buf += cmd
 418         f = False
 419     if not f:
 420         out.write("%s\n" % (buf,))
 421
 422 def main(argv):
 423     global service
 424     opts, args = getopt.getopt(argv[1:], "hD:")
 425     for o, a in opts:
 426         if o == "-h":
 427             if len(args) > 0:
 428                 cmd = commands.get(args[0])
 429                 if cmd is None:
 430                     sys.stderr.write("acmecert: unknown command: %s\n" % (args[0],))
 431                     sys.exit(1)
 432                 sys.stdout.write("%s\n" % (cmd.__doc__,))
 433             else:
 434                 usage(sys.stdout)
 435             sys.exit(0)
 436         elif o == "-D":
 437             service = a
 438     if len(args) < 1:
 439         usage(sys.stderr)
 440         sys.exit(1)
 441     cmd = commands.get(args[0])
 442     if cmd is None:
 443         sys.stderr.write("acmecert: unknown command: %s\n" % (args[0],))
 444         usage(sys.stderr)
 445         sys.exit(1)
 446     try:
 447         cmd(args)
 448     except usageerr:
 449         sys.stderr.write("%s\n" % (cmd.__doc__,))
 450         sys.exit(1)
 451
 452 if __name__ == "__main__":
 453     try:
 454         main(sys.argv)
 455     except KeyboardInterrupt:
 456         signal.signal(signal.SIGINT, signal.SIG_DFL)
 457         os.kill(os.getpid(), signal.SIGINT)