tor/scripts/codegen/makedesc.py
2019-01-16 12:33:22 -05:00

352 lines
11 KiB
Python

#!/usr/bin/python
# Copyright 2014-2019, The Tor Project, Inc.
# See LICENSE for license information
# This is a kludgey python script that uses ctypes and openssl to sign
# router descriptors and extrainfo documents and put all the keys in
# the right places. There are examples at the end of the file.
# I've used this to make inputs for unit tests. I wouldn't suggest
# using it for anything else.
import base64
import binascii
import ctypes
import ctypes.util
import hashlib
import optparse
import os
import re
import struct
import time
import UserDict
import slow_ed25519
import slownacl_curve25519
import ed25519_exts_ref
# Pull in the openssl stuff we need.
crypt = ctypes.CDLL(ctypes.util.find_library('crypto'))
BIO_s_mem = crypt.BIO_s_mem
BIO_s_mem.argtypes = []
BIO_s_mem.restype = ctypes.c_void_p
BIO_new = crypt.BIO_new
BIO_new.argtypes = [ctypes.c_void_p]
BIO_new.restype = ctypes.c_void_p
crypt.BIO_free.argtypes = [ctypes.c_void_p]
crypt.BIO_free.restype = ctypes.c_int
crypt.BIO_ctrl.argtypes = [ctypes.c_void_p, ctypes.c_int, ctypes.c_long, ctypes.c_void_p ]
crypt.BIO_ctrl.restype = ctypes.c_long
crypt.PEM_write_bio_RSAPublicKey.argtypes = [ ctypes.c_void_p, ctypes.c_void_p ]
crypt.PEM_write_bio_RSAPublicKey.restype = ctypes.c_int
RSA_generate_key = crypt.RSA_generate_key
RSA_generate_key.argtypes = [ctypes.c_int, ctypes.c_ulong, ctypes.c_void_p, ctypes.c_void_p]
RSA_generate_key.restype = ctypes.c_void_p
RSA_private_encrypt = crypt.RSA_private_encrypt
RSA_private_encrypt.argtypes = [
ctypes.c_int, ctypes.c_char_p, ctypes.c_void_p, ctypes.c_void_p, ctypes.c_int ]
RSA_private_encrypt.restype = ctypes.c_int
i2d_RSAPublicKey = crypt.i2d_RSAPublicKey
i2d_RSAPublicKey.argtypes = [
ctypes.c_void_p, ctypes.POINTER(ctypes.c_char_p)
]
i2d_RSAPublicKey.restype = ctypes.c_int
def rsa_sign(msg, rsa):
buf = ctypes.create_string_buffer(1024)
n = RSA_private_encrypt(len(msg), msg, buf, rsa, 1)
if n <= 0:
raise Exception()
return buf.raw[:n]
def b64(x):
x = base64.b64encode(x)
res = []
for i in xrange(0, len(x), 64):
res.append(x[i:i+64]+"\n")
return "".join(res)
def bio_extract(bio):
buf = ctypes.c_char_p()
length = crypt.BIO_ctrl(bio, 3, 0, ctypes.byref(buf))
return ctypes.string_at(buf, length)
def make_rsa_key(e=65537):
rsa = crypt.RSA_generate_key(1024, e, None, None)
bio = BIO_new(BIO_s_mem())
crypt.PEM_write_bio_RSAPublicKey(bio, rsa)
pem = bio_extract(bio).rstrip()
crypt.BIO_free(bio)
buf = ctypes.create_string_buffer(1024)
pBuf = ctypes.c_char_p(ctypes.addressof(buf))
n = crypt.i2d_RSAPublicKey(rsa, ctypes.byref(pBuf))
s = buf.raw[:n]
digest = hashlib.sha1(s).digest()
return (rsa,pem,digest)
def makeEdSigningKeyCert(sk_master, pk_master, pk_signing, date,
includeSigning=False, certType=1):
assert len(pk_signing) == len(pk_master) == 32
expiration = struct.pack("!L", date//3600)
if includeSigning:
extensions = "\x01\x00\x20\x04\x00%s"%(pk_master)
else:
extensions = "\x00"
signed = "\x01%s%s\x01%s%s" % (
chr(certType), expiration, pk_signing, extensions)
signature = ed25519_exts_ref.signatureWithESK(signed, sk_master, pk_master)
assert len(signature) == 64
return signed+signature
def objwrap(identifier, body):
return ("-----BEGIN {0}-----\n"
"{1}"
"-----END {0}-----").format(identifier, body)
MAGIC1 = "<<<<<<MAGIC>>>>>>"
MAGIC2 = "<<<<<!#!#!#XYZZY#!#!#!>>>>>"
class OnDemandKeys(object):
def __init__(self, certDate=None):
if certDate is None:
certDate = time.time() + 86400
self.certDate = certDate
self.rsa_id = None
self.rsa_onion_key = None
self.ed_id_sk = None
self.ntor_sk = None
self.ntor_crosscert = None
self.rsa_crosscert_ed = None
self.rsa_crosscert_noed = None
@property
def RSA_IDENTITY(self):
if self.rsa_id is None:
self.rsa_id, self.rsa_ident_pem, self.rsa_id_digest = make_rsa_key()
return self.rsa_ident_pem
@property
def RSA_ID_DIGEST(self):
self.RSA_IDENTITY
return self.rsa_id_digest
@property
def RSA_FINGERPRINT_NOSPACE(self):
return binascii.b2a_hex(self.RSA_ID_DIGEST).upper()
@property
def RSA_ONION_KEY(self):
if self.rsa_onion_key is None:
self.rsa_onion_key, self.rsa_onion_pem, _ = make_rsa_key()
return self.rsa_onion_pem
@property
def RSA_FINGERPRINT(self):
hexdigest = self.RSA_FINGERPRINT_NOSPACEK
return " ".join(hexdigest[i:i+4] for i in range(0,len(hexdigest),4))
@property
def RSA_SIGNATURE(self):
return MAGIC1
@property
def ED_SIGNATURE(self):
return MAGIC2
@property
def NTOR_ONION_KEY(self):
if self.ntor_sk is None:
self.ntor_sk = slownacl_curve25519.Private()
self.ntor_pk = self.ntor_sk.get_public()
return base64.b64encode(self.ntor_pk.serialize())
@property
def ED_CERT(self):
if self.ed_id_sk is None:
self.ed_id_sk = ed25519_exts_ref.expandSK(os.urandom(32))
self.ed_signing_sk = ed25519_exts_ref.expandSK(os.urandom(32))
self.ed_id_pk = ed25519_exts_ref.publickeyFromESK(self.ed_id_sk)
self.ed_signing_pk = ed25519_exts_ref.publickeyFromESK(self.ed_signing_sk)
self.ed_cert = makeEdSigningKeyCert(self.ed_id_sk, self.ed_id_pk, self.ed_signing_pk, self.certDate, includeSigning=True, certType=4)
return objwrap('ED25519 CERT', b64(self.ed_cert))
@property
def NTOR_CROSSCERT(self):
if self.ntor_crosscert is None:
self.ED_CERT
self.NTOR_ONION_KEY
ed_privkey = self.ntor_sk.serialize() + os.urandom(32)
ed_pub0 = ed25519_exts_ref.publickeyFromESK(ed_privkey)
sign = (ord(ed_pub0[31]) & 255) >> 7
self.ntor_crosscert = makeEdSigningKeyCert(self.ntor_sk.serialize() + os.urandom(32), ed_pub0, self.ed_id_pk, self.certDate, certType=10)
self.ntor_crosscert_sign = sign
return objwrap('ED25519 CERT', b64(self.ntor_crosscert))
@property
def NTOR_CROSSCERT_SIGN(self):
self.NTOR_CROSSCERT
return self.ntor_crosscert_sign
@property
def RSA_CROSSCERT_NOED(self):
if self.rsa_crosscert_noed is None:
self.RSA_ONION_KEY
signed = self.RSA_ID_DIGEST
self.rsa_crosscert_noed = rsa_sign(signed, self.rsa_onion_key)
return objwrap("CROSSCERT",b64(self.rsa_crosscert_noed))
@property
def RSA_CROSSCERT_ED(self):
if self.rsa_crosscert_ed is None:
self.RSA_ONION_KEY
self.ED_CERT
signed = self.RSA_ID_DIGEST + self.ed_id_pk
self.rsa_crosscert_ed = rsa_sign(signed, self.rsa_onion_key)
return objwrap("CROSSCERT",b64(self.rsa_crosscert_ed))
def sign_desc(self, body):
idx = body.rfind("\nrouter-sig-ed25519 ")
if idx >= 0:
self.ED_CERT
signed_part = body[:idx+len("\nrouter-sig-ed25519 ")]
signed_part = "Tor router descriptor signature v1" + signed_part
digest = hashlib.sha256(signed_part).digest()
ed_sig = ed25519_exts_ref.signatureWithESK(digest,
self.ed_signing_sk, self.ed_signing_pk)
body = body.replace(MAGIC2, base64.b64encode(ed_sig).replace("=",""))
idx = body.rindex("\nrouter-signature")
end_of_sig = body.index("\n", idx+1)
signed_part = body[:end_of_sig+1]
digest = hashlib.sha1(signed_part).digest()
assert len(digest) == 20
rsasig = rsa_sign(digest, self.rsa_id)
body = body.replace(MAGIC1, objwrap("SIGNATURE", b64(rsasig)))
return body
def signdesc(body, args_out=None):
rsa, ident_pem, id_digest = make_key()
_, onion_pem, _ = make_key()
need_ed = '{ED25519-CERT}' in body or '{ED25519-SIGNATURE}' in body
if need_ed:
sk_master = os.urandom(32)
sk_signing = os.urandom(32)
pk_master = slow_ed25519.pubkey(sk_master)
pk_signing = slow_ed25519.pubkey(sk_signing)
hexdigest = binascii.b2a_hex(id_digest).upper()
fingerprint = " ".join(hexdigest[i:i+4] for i in range(0,len(hexdigest),4))
MAGIC = "<<<<<<MAGIC>>>>>>"
MORE_MAGIC = "<<<<<!#!#!#XYZZY#!#!#!>>>>>"
args = {
"RSA-IDENTITY" : ident_pem,
"ONION-KEY" : onion_pem,
"FINGERPRINT" : fingerprint,
"FINGERPRINT-NOSPACE" : hexdigest,
"RSA-SIGNATURE" : MAGIC
}
if need_ed:
args['ED25519-CERT'] = makeEdSigningKeyCert(
sk_master, pk_master, pk_signing)
args['ED25519-SIGNATURE'] = MORE_MAGIC
if args_out:
args_out.update(args)
body = body.format(**args)
idx = body.rindex("\nrouter-signature")
end_of_sig = body.index("\n", idx+1)
signed_part = body[:end_of_sig+1]
digest = hashlib.sha1(signed_part).digest()
assert len(digest) == 20
buf = ctypes.create_string_buffer(1024)
n = RSA_private_encrypt(20, digest, buf, rsa, 1)
sig = buf.raw[:n]
sig = """-----BEGIN SIGNATURE-----
%s
-----END SIGNATURE-----""" % b64(sig).rstrip()
body = body.replace(MAGIC, sig)
return body.rstrip()
def print_c_string(ident, body):
print "static const char %s[] =" % ident
for line in body.split("\n"):
print ' "%s\\n"' %(line)
print " ;"
def emit_ri(name, body):
info = OnDemandKeys()
body = body.format(d=info)
body = info.sign_desc(body)
print_c_string("EX_RI_%s"%name.upper(), body)
def emit_ei(name, body):
info = OnDemandKeys()
body = body.format(d=info)
body = info.sign_desc(body)
print_c_string("EX_EI_%s"%name.upper(), body)
print 'const char EX_EI_{NAME}_FP[] = "{d.RSA_FINGERPRINT_NOSPACE}";'.format(
d=info, NAME=name.upper())
print_c_string("EX_EI_%s_KEY"%name.upper(), info.RSA_IDENTITY)
def analyze(s):
fields = {}
while s.startswith(":::"):
first,s=s.split("\n", 1)
m = re.match(r'^:::(\w+)=(.*)',first)
if not m:
raise ValueError(first)
k,v = m.groups()
fields[k] = v
return fields, s
def process_file(s):
fields, s = analyze(s)
try:
name = fields['name']
tp = fields['type']
except KeyError:
raise ValueError("missing required field")
if tp == 'ei':
emit_ei(name, s)
elif tp == 'ri':
emit_ri(name, s)
else:
raise ValueError("unrecognized type")
if __name__ == '__main__':
import sys
for fn in sys.argv[1:]:
process_file(open(fn).read())