mirror of
https://gitlab.torproject.org/tpo/core/tor.git
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79db24b3d5
Extrainfo documents are now ed-signed just as are router descriptors, according to proposal 220. This patch also includes some more tests for successful/failing parsing, and fixes a crash bug in ed25519 descriptor parsing.
352 lines
11 KiB
Python
352 lines
11 KiB
Python
#!/usr/bin/python
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# Copyright 2014-2015, The Tor Project, Inc.
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# See LICENSE for license information
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# This is a kludgey python script that uses ctypes and openssl to sign
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# router descriptors and extrainfo documents and put all the keys in
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# the right places. There are examples at the end of the file.
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# I've used this to make inputs for unit tests. I wouldn't suggest
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# using it for anything else.
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import base64
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import binascii
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import ctypes
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import ctypes.util
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import hashlib
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import optparse
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import os
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import re
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import struct
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import time
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import UserDict
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import slow_ed25519
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import slownacl_curve25519
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import ed25519_exts_ref
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# Pull in the openssl stuff we need.
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crypt = ctypes.CDLL(ctypes.util.find_library('crypto'))
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BIO_s_mem = crypt.BIO_s_mem
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BIO_s_mem.argtypes = []
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BIO_s_mem.restype = ctypes.c_void_p
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BIO_new = crypt.BIO_new
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BIO_new.argtypes = [ctypes.c_void_p]
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BIO_new.restype = ctypes.c_void_p
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crypt.BIO_free.argtypes = [ctypes.c_void_p]
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crypt.BIO_free.restype = ctypes.c_int
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crypt.BIO_ctrl.argtypes = [ctypes.c_void_p, ctypes.c_int, ctypes.c_long, ctypes.c_void_p ]
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crypt.BIO_ctrl.restype = ctypes.c_long
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crypt.PEM_write_bio_RSAPublicKey.argtypes = [ ctypes.c_void_p, ctypes.c_void_p ]
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crypt.PEM_write_bio_RSAPublicKey.restype = ctypes.c_int
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RSA_generate_key = crypt.RSA_generate_key
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RSA_generate_key.argtypes = [ctypes.c_int, ctypes.c_ulong, ctypes.c_void_p, ctypes.c_void_p]
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RSA_generate_key.restype = ctypes.c_void_p
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RSA_private_encrypt = crypt.RSA_private_encrypt
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RSA_private_encrypt.argtypes = [
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ctypes.c_int, ctypes.c_char_p, ctypes.c_void_p, ctypes.c_void_p, ctypes.c_int ]
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RSA_private_encrypt.restype = ctypes.c_int
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i2d_RSAPublicKey = crypt.i2d_RSAPublicKey
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i2d_RSAPublicKey.argtypes = [
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ctypes.c_void_p, ctypes.POINTER(ctypes.c_char_p)
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]
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i2d_RSAPublicKey.restype = ctypes.c_int
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def rsa_sign(msg, rsa):
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buf = ctypes.create_string_buffer(1024)
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n = RSA_private_encrypt(len(msg), msg, buf, rsa, 1)
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if n <= 0:
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raise Exception()
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return buf.raw[:n]
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def b64(x):
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x = base64.b64encode(x)
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res = []
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for i in xrange(0, len(x), 64):
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res.append(x[i:i+64]+"\n")
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return "".join(res)
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def bio_extract(bio):
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buf = ctypes.c_char_p()
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length = crypt.BIO_ctrl(bio, 3, 0, ctypes.byref(buf))
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return ctypes.string_at(buf, length)
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def make_rsa_key(e=65537):
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rsa = crypt.RSA_generate_key(1024, e, None, None)
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bio = BIO_new(BIO_s_mem())
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crypt.PEM_write_bio_RSAPublicKey(bio, rsa)
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pem = bio_extract(bio).rstrip()
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crypt.BIO_free(bio)
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buf = ctypes.create_string_buffer(1024)
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pBuf = ctypes.c_char_p(ctypes.addressof(buf))
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n = crypt.i2d_RSAPublicKey(rsa, ctypes.byref(pBuf))
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s = buf.raw[:n]
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digest = hashlib.sha1(s).digest()
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return (rsa,pem,digest)
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def makeEdSigningKeyCert(sk_master, pk_master, pk_signing, date,
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includeSigning=False, certType=1):
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assert len(pk_signing) == len(pk_master) == 32
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expiration = struct.pack("!L", date//3600)
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if includeSigning:
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extensions = "\x01\x00\x20\x04\x00%s"%(pk_master)
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else:
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extensions = "\x00"
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signed = "\x01%s%s\x01%s%s" % (
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chr(certType), expiration, pk_signing, extensions)
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signature = ed25519_exts_ref.signatureWithESK(signed, sk_master, pk_master)
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assert len(signature) == 64
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return signed+signature
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def objwrap(identifier, body):
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return ("-----BEGIN {0}-----\n"
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"{1}"
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"-----END {0}-----").format(identifier, body)
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MAGIC1 = "<<<<<<MAGIC>>>>>>"
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MAGIC2 = "<<<<<!#!#!#XYZZY#!#!#!>>>>>"
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class OnDemandKeys(object):
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def __init__(self, certDate=None):
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if certDate is None:
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certDate = time.time() + 86400
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self.certDate = certDate
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self.rsa_id = None
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self.rsa_onion_key = None
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self.ed_id_sk = None
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self.ntor_sk = None
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self.ntor_crosscert = None
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self.rsa_crosscert_ed = None
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self.rsa_crosscert_noed = None
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@property
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def RSA_IDENTITY(self):
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if self.rsa_id is None:
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self.rsa_id, self.rsa_ident_pem, self.rsa_id_digest = make_rsa_key()
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return self.rsa_ident_pem
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@property
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def RSA_ID_DIGEST(self):
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self.RSA_IDENTITY
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return self.rsa_id_digest
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@property
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def RSA_FINGERPRINT_NOSPACE(self):
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return binascii.b2a_hex(self.RSA_ID_DIGEST).upper()
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@property
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def RSA_ONION_KEY(self):
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if self.rsa_onion_key is None:
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self.rsa_onion_key, self.rsa_onion_pem, _ = make_rsa_key()
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return self.rsa_onion_pem
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@property
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def RSA_FINGERPRINT(self):
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hexdigest = self.RSA_FINGERPRINT_NOSPACEK
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return " ".join(hexdigest[i:i+4] for i in range(0,len(hexdigest),4))
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@property
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def RSA_SIGNATURE(self):
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return MAGIC1
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@property
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def ED_SIGNATURE(self):
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return MAGIC2
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@property
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def NTOR_ONION_KEY(self):
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if self.ntor_sk is None:
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self.ntor_sk = slownacl_curve25519.Private()
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self.ntor_pk = self.ntor_sk.get_public()
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return base64.b64encode(self.ntor_pk.serialize())
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@property
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def ED_CERT(self):
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if self.ed_id_sk is None:
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self.ed_id_sk = ed25519_exts_ref.expandSK(os.urandom(32))
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self.ed_signing_sk = ed25519_exts_ref.expandSK(os.urandom(32))
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self.ed_id_pk = ed25519_exts_ref.publickeyFromESK(self.ed_id_sk)
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self.ed_signing_pk = ed25519_exts_ref.publickeyFromESK(self.ed_signing_sk)
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self.ed_cert = makeEdSigningKeyCert(self.ed_id_sk, self.ed_id_pk, self.ed_signing_pk, self.certDate, includeSigning=True, certType=4)
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return objwrap('ED25519 CERT', b64(self.ed_cert))
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@property
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def NTOR_CROSSCERT(self):
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if self.ntor_crosscert is None:
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self.ED_CERT
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self.NTOR_ONION_KEY
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ed_privkey = self.ntor_sk.serialize() + os.urandom(32)
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ed_pub0 = ed25519_exts_ref.publickeyFromESK(ed_privkey)
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sign = (ord(ed_pub0[31]) & 255) >> 7
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self.ntor_crosscert = makeEdSigningKeyCert(self.ntor_sk.serialize() + os.urandom(32), ed_pub0, self.ed_id_pk, self.certDate, certType=10)
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self.ntor_crosscert_sign = sign
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return objwrap('ED25519 CERT', b64(self.ntor_crosscert))
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@property
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def NTOR_CROSSCERT_SIGN(self):
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self.NTOR_CROSSCERT
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return self.ntor_crosscert_sign
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@property
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def RSA_CROSSCERT_NOED(self):
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if self.rsa_crosscert_noed is None:
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self.RSA_ONION_KEY
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signed = self.RSA_ID_DIGEST
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self.rsa_crosscert_noed = rsa_sign(signed, self.rsa_onion_key)
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return objwrap("CROSSCERT",b64(self.rsa_crosscert_noed))
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@property
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def RSA_CROSSCERT_ED(self):
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if self.rsa_crosscert_ed is None:
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self.RSA_ONION_KEY
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self.ED_CERT
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signed = self.RSA_ID_DIGEST + self.ed_id_pk
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self.rsa_crosscert_ed = rsa_sign(signed, self.rsa_onion_key)
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return objwrap("CROSSCERT",b64(self.rsa_crosscert_ed))
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def sign_desc(self, body):
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idx = body.rfind("\nrouter-sig-ed25519 ")
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if idx >= 0:
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self.ED_CERT
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signed_part = body[:idx+len("\nrouter-sig-ed25519 ")]
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signed_part = "Tor router descriptor signature v1" + signed_part
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digest = hashlib.sha256(signed_part).digest()
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ed_sig = ed25519_exts_ref.signatureWithESK(digest,
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self.ed_signing_sk, self.ed_signing_pk)
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body = body.replace(MAGIC2, base64.b64encode(ed_sig).replace("=",""))
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idx = body.rindex("\nrouter-signature")
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end_of_sig = body.index("\n", idx+1)
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signed_part = body[:end_of_sig+1]
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digest = hashlib.sha1(signed_part).digest()
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assert len(digest) == 20
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rsasig = rsa_sign(digest, self.rsa_id)
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body = body.replace(MAGIC1, objwrap("SIGNATURE", b64(rsasig)))
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return body
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def signdesc(body, args_out=None):
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rsa, ident_pem, id_digest = make_key()
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_, onion_pem, _ = make_key()
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need_ed = '{ED25519-CERT}' in body or '{ED25519-SIGNATURE}' in body
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if need_ed:
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sk_master = os.urandom(32)
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sk_signing = os.urandom(32)
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pk_master = slow_ed25519.pubkey(sk_master)
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pk_signing = slow_ed25519.pubkey(sk_signing)
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hexdigest = binascii.b2a_hex(id_digest).upper()
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fingerprint = " ".join(hexdigest[i:i+4] for i in range(0,len(hexdigest),4))
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MAGIC = "<<<<<<MAGIC>>>>>>"
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MORE_MAGIC = "<<<<<!#!#!#XYZZY#!#!#!>>>>>"
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args = {
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"RSA-IDENTITY" : ident_pem,
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"ONION-KEY" : onion_pem,
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"FINGERPRINT" : fingerprint,
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"FINGERPRINT-NOSPACE" : hexdigest,
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"RSA-SIGNATURE" : MAGIC
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}
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if need_ed:
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args['ED25519-CERT'] = makeEdSigningKeyCert(
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sk_master, pk_master, pk_signing)
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args['ED25519-SIGNATURE'] = MORE_MAGIC
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if args_out:
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args_out.update(args)
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body = body.format(**args)
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idx = body.rindex("\nrouter-signature")
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end_of_sig = body.index("\n", idx+1)
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signed_part = body[:end_of_sig+1]
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digest = hashlib.sha1(signed_part).digest()
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assert len(digest) == 20
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buf = ctypes.create_string_buffer(1024)
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n = RSA_private_encrypt(20, digest, buf, rsa, 1)
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sig = buf.raw[:n]
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sig = """-----BEGIN SIGNATURE-----
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%s
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-----END SIGNATURE-----""" % b64(sig).rstrip()
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body = body.replace(MAGIC, sig)
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return body.rstrip()
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def print_c_string(ident, body):
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print "static const char %s[] =" % ident
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for line in body.split("\n"):
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print ' "%s\\n"' %(line)
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print " ;"
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def emit_ri(name, body):
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info = OnDemandKeys()
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body = body.format(d=info)
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body = info.sign_desc(body)
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print_c_string("EX_RI_%s"%name.upper(), body)
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def emit_ei(name, body):
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info = OnDemandKeys()
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body = body.format(d=info)
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body = info.sign_desc(body)
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print_c_string("EX_EI_%s"%name.upper(), body)
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print 'const char EX_EI_{NAME}_FP[] = "{d.RSA_FINGERPRINT_NOSPACE}";'.format(
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d=info, NAME=name.upper())
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print_c_string("EX_EI_%s_KEY"%name.upper(), info.RSA_IDENTITY)
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def analyze(s):
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fields = {}
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while s.startswith(":::"):
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first,s=s.split("\n", 1)
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m = re.match(r'^:::(\w+)=(.*)',first)
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if not m:
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raise ValueError(first)
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k,v = m.groups()
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fields[k] = v
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return fields, s
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def process_file(s):
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fields, s = analyze(s)
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try:
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name = fields['name']
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tp = fields['type']
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except KeyError:
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raise ValueError("missing required field")
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if tp == 'ei':
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emit_ei(name, s)
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elif tp == 'ri':
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emit_ri(name, s)
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else:
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raise ValueError("unrecognized type")
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if __name__ == '__main__':
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import sys
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for fn in sys.argv[1:]:
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process_file(open(fn).read())
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