1 #----------------------------------------------------------------------
2 # Copyright (c) 2008 Board of Trustees, Princeton University
4 # Permission is hereby granted, free of charge, to any person obtaining
5 # a copy of this software and/or hardware specification (the "Work") to
6 # deal in the Work without restriction, including without limitation the
7 # rights to use, copy, modify, merge, publish, distribute, sublicense,
8 # and/or sell copies of the Work, and to permit persons to whom the Work
9 # is furnished to do so, subject to the following conditions:
11 # The above copyright notice and this permission notice shall be
12 # included in all copies or substantial portions of the Work.
14 # THE WORK IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
15 # OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
16 # MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
17 # NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
18 # HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
19 # WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
20 # OUT OF OR IN CONNECTION WITH THE WORK OR THE USE OR OTHER DEALINGS
22 #----------------------------------------------------------------------
25 # SFA uses two crypto libraries: pyOpenSSL and M2Crypto to implement
26 # the necessary crypto functionality. Ideally just one of these libraries
27 # would be used, but unfortunately each of these libraries is independently
28 # lacking. The pyOpenSSL library is missing many necessary functions, and
29 # the M2Crypto library has crashed inside of some of the functions. The
30 # design decision is to use pyOpenSSL whenever possible as it seems more
31 # stable, and only use M2Crypto for those functions that are not possible
34 # This module exports two classes: Keypair and Certificate.
42 from tempfile import mkstemp
44 from OpenSSL import crypto
46 from M2Crypto import X509
48 from sfa.util.sfalogging import sfa_logger
49 from sfa.util.namespace import urn_to_hrn
50 from sfa.util.faults import *
52 def convert_public_key(key):
53 keyconvert_path = "/usr/bin/keyconvert.py"
54 if not os.path.isfile(keyconvert_path):
55 raise IOError, "Could not find keyconvert in %s" % keyconvert_path
57 # we can only convert rsa keys
61 (ssh_f, ssh_fn) = tempfile.mkstemp()
62 ssl_fn = tempfile.mktemp()
66 cmd = keyconvert_path + " " + ssh_fn + " " + ssl_fn
69 # this check leaves the temporary file containing the public key so
70 # that it can be expected to see why it failed.
71 # TODO: for production, cleanup the temporary files
72 if not os.path.exists(ssl_fn):
77 k.load_pubkey_from_file(ssl_fn)
79 sfa_logger().log_exc("convert_public_key caught exception")
82 # remove the temporary files
89 # Public-private key pairs are implemented by the Keypair class.
90 # A Keypair object may represent both a public and private key pair, or it
91 # may represent only a public key (this usage is consistent with OpenSSL).
94 key = None # public/private keypair
95 m2key = None # public key (m2crypto format)
98 # Creates a Keypair object
99 # @param create If create==True, creates a new public/private key and
100 # stores it in the object
101 # @param string If string!=None, load the keypair from the string (PEM)
102 # @param filename If filename!=None, load the keypair from the file
104 def __init__(self, create=False, string=None, filename=None):
108 self.load_from_string(string)
110 self.load_from_file(filename)
113 # Create a RSA public/private key pair and store it inside the keypair object
116 self.key = crypto.PKey()
117 self.key.generate_key(crypto.TYPE_RSA, 1024)
120 # Save the private key to a file
121 # @param filename name of file to store the keypair in
123 def save_to_file(self, filename):
124 open(filename, 'w').write(self.as_pem())
125 self.filename=filename
128 # Load the private key from a file. Implicity the private key includes the public key.
130 def load_from_file(self, filename):
131 buffer = open(filename, 'r').read()
132 self.load_from_string(buffer)
133 self.filename=filename
136 # Load the private key from a string. Implicitly the private key includes the public key.
138 def load_from_string(self, string):
139 self.key = crypto.load_privatekey(crypto.FILETYPE_PEM, string)
140 self.m2key = M2Crypto.EVP.load_key_string(string)
143 # Load the public key from a string. No private key is loaded.
145 def load_pubkey_from_file(self, filename):
146 # load the m2 public key
147 m2rsakey = M2Crypto.RSA.load_pub_key(filename)
148 self.m2key = M2Crypto.EVP.PKey()
149 self.m2key.assign_rsa(m2rsakey)
151 # create an m2 x509 cert
152 m2name = M2Crypto.X509.X509_Name()
153 m2name.add_entry_by_txt(field="CN", type=0x1001, entry="junk", len=-1, loc=-1, set=0)
154 m2x509 = M2Crypto.X509.X509()
155 m2x509.set_pubkey(self.m2key)
156 m2x509.set_serial_number(0)
157 m2x509.set_issuer_name(m2name)
158 m2x509.set_subject_name(m2name)
159 ASN1 = M2Crypto.ASN1.ASN1_UTCTIME()
161 m2x509.set_not_before(ASN1)
162 m2x509.set_not_after(ASN1)
163 junk_key = Keypair(create=True)
164 m2x509.sign(pkey=junk_key.get_m2_pkey(), md="sha1")
166 # convert the m2 x509 cert to a pyopenssl x509
167 m2pem = m2x509.as_pem()
168 pyx509 = crypto.load_certificate(crypto.FILETYPE_PEM, m2pem)
170 # get the pyopenssl pkey from the pyopenssl x509
171 self.key = pyx509.get_pubkey()
172 self.filename=filename
175 # Load the public key from a string. No private key is loaded.
177 def load_pubkey_from_string(self, string):
178 (f, fn) = tempfile.mkstemp()
181 self.load_pubkey_from_file(fn)
185 # Return the private key in PEM format.
188 return crypto.dump_privatekey(crypto.FILETYPE_PEM, self.key)
191 # Return an M2Crypto key object
193 def get_m2_pkey(self):
195 self.m2key = M2Crypto.EVP.load_key_string(self.as_pem())
199 # Returns a string containing the public key represented by this object.
201 def get_pubkey_string(self):
202 m2pkey = self.get_m2_pkey()
203 return base64.b64encode(m2pkey.as_der())
206 # Return an OpenSSL pkey object
208 def get_openssl_pkey(self):
212 # Given another Keypair object, return TRUE if the two keys are the same.
214 def is_same(self, pkey):
215 return self.as_pem() == pkey.as_pem()
217 def sign_string(self, data):
218 k = self.get_m2_pkey()
221 return base64.b64encode(k.sign_final())
223 def verify_string(self, data, sig):
224 k = self.get_m2_pkey()
226 k.verify_update(data)
227 return M2Crypto.m2.verify_final(k.ctx, base64.b64decode(sig), k.pkey)
229 def compute_hash(self, value):
230 return self.sign_string(str(value))
233 def get_filename(self):
234 return getattr(self,'filename',None)
236 def dump (self, *args, **kwargs):
237 print self.dump_string(*args, **kwargs)
239 def dump_string (self):
241 result += "KEYPAIR: pubkey=%40s..."%self.get_pubkey_string()
242 filename=self.get_filename()
243 if filename: result += "Filename %s\n"%filename
247 # The certificate class implements a general purpose X509 certificate, making
248 # use of the appropriate pyOpenSSL or M2Crypto abstractions. It also adds
249 # several addition features, such as the ability to maintain a chain of
250 # parent certificates, and storage of application-specific data.
252 # Certificates include the ability to maintain a chain of parents. Each
253 # certificate includes a pointer to it's parent certificate. When loaded
254 # from a file or a string, the parent chain will be automatically loaded.
255 # When saving a certificate to a file or a string, the caller can choose
256 # whether to save the parent certificates as well.
266 separator="-----parent-----"
269 # Create a certificate object.
271 # @param create If create==True, then also create a blank X509 certificate.
272 # @param subject If subject!=None, then create a blank certificate and set
274 # @param string If string!=None, load the certficate from the string.
275 # @param filename If filename!=None, load the certficiate from the file.
277 def __init__(self, create=False, subject=None, string=None, filename=None, intermediate=None):
279 if create or subject:
282 self.set_subject(subject)
284 self.load_from_string(string)
286 self.load_from_file(filename)
289 self.set_intermediate_ca(intermediate)
292 # Create a blank X509 certificate and store it in this object.
295 self.cert = crypto.X509()
296 self.cert.set_serial_number(3)
297 self.cert.gmtime_adj_notBefore(0)
298 self.cert.gmtime_adj_notAfter(60*60*24*365*5) # five years
301 # Given a pyOpenSSL X509 object, store that object inside of this
302 # certificate object.
304 def load_from_pyopenssl_x509(self, x509):
308 # Load the certificate from a string
310 def load_from_string(self, string):
311 # if it is a chain of multiple certs, then split off the first one and
312 # load it (support for the ---parent--- tag as well as normal chained certs)
314 string = string.strip()
317 if not string.startswith('-----'):
318 string = '-----BEGIN CERTIFICATE-----\n%s\n-----END CERTIFICATE-----' % string
322 if string.count('-----BEGIN CERTIFICATE-----') > 1 and \
323 string.count(Certificate.separator) == 0:
324 parts = string.split('-----END CERTIFICATE-----',1)
325 parts[0] += '-----END CERTIFICATE-----'
327 parts = string.split(Certificate.separator, 1)
329 self.cert = crypto.load_certificate(crypto.FILETYPE_PEM, parts[0])
331 # if there are more certs, then create a parent and let the parent load
332 # itself from the remainder of the string
333 if len(parts) > 1 and parts[1] != '':
334 self.parent = self.__class__()
335 self.parent.load_from_string(parts[1])
338 # Load the certificate from a file
340 def load_from_file(self, filename):
341 file = open(filename)
343 self.load_from_string(string)
344 self.filename=filename
347 # Save the certificate to a string.
349 # @param save_parents If save_parents==True, then also save the parent certificates.
351 def save_to_string(self, save_parents=True):
352 string = crypto.dump_certificate(crypto.FILETYPE_PEM, self.cert)
353 if save_parents and self.parent:
354 string = string + self.parent.save_to_string(save_parents)
358 # Save the certificate to a file.
359 # @param save_parents If save_parents==True, then also save the parent certificates.
361 def save_to_file(self, filename, save_parents=True, filep=None):
362 string = self.save_to_string(save_parents=save_parents)
366 f = open(filename, 'w')
369 self.filename=filename
372 # Save the certificate to a random file in /tmp/
373 # @param save_parents If save_parents==True, then also save the parent certificates.
374 def save_to_random_tmp_file(self, save_parents=True):
375 fp, filename = mkstemp(suffix='cert', text=True)
376 fp = os.fdopen(fp, "w")
377 self.save_to_file(filename, save_parents=True, filep=fp)
381 # Sets the issuer private key and name
382 # @param key Keypair object containing the private key of the issuer
383 # @param subject String containing the name of the issuer
384 # @param cert (optional) Certificate object containing the name of the issuer
386 def set_issuer(self, key, subject=None, cert=None):
389 # it's a mistake to use subject and cert params at the same time
391 if isinstance(subject, dict) or isinstance(subject, str):
392 req = crypto.X509Req()
393 reqSubject = req.get_subject()
394 if (isinstance(subject, dict)):
395 for key in reqSubject.keys():
396 setattr(reqSubject, key, subject[key])
398 setattr(reqSubject, "CN", subject)
400 # subject is not valid once req is out of scope, so save req
403 # if a cert was supplied, then get the subject from the cert
404 subject = cert.cert.get_subject()
406 self.issuerSubject = subject
409 # Get the issuer name
411 def get_issuer(self, which="CN"):
412 x = self.cert.get_issuer()
413 return getattr(x, which)
416 # Set the subject name of the certificate
418 def set_subject(self, name):
419 req = crypto.X509Req()
420 subj = req.get_subject()
421 if (isinstance(name, dict)):
422 for key in name.keys():
423 setattr(subj, key, name[key])
425 setattr(subj, "CN", name)
426 self.cert.set_subject(subj)
428 # Get the subject name of the certificate
430 def get_subject(self, which="CN"):
431 x = self.cert.get_subject()
432 return getattr(x, which)
435 # Get the public key of the certificate.
437 # @param key Keypair object containing the public key
439 def set_pubkey(self, key):
440 assert(isinstance(key, Keypair))
441 self.cert.set_pubkey(key.get_openssl_pkey())
444 # Get the public key of the certificate.
445 # It is returned in the form of a Keypair object.
447 def get_pubkey(self):
448 m2x509 = X509.load_cert_string(self.save_to_string())
450 pkey.key = self.cert.get_pubkey()
451 pkey.m2key = m2x509.get_pubkey()
454 def set_intermediate_ca(self, val):
455 self.intermediate = val
457 self.add_extension('basicConstraints', 1, 'CA:TRUE')
462 # Add an X509 extension to the certificate. Add_extension can only be called
463 # once for a particular extension name, due to limitations in the underlying
466 # @param name string containing name of extension
467 # @param value string containing value of the extension
469 def add_extension(self, name, critical, value):
470 ext = crypto.X509Extension (name, critical, value)
471 self.cert.add_extensions([ext])
474 # Get an X509 extension from the certificate
476 def get_extension(self, name):
478 # pyOpenSSL does not have a way to get extensions
479 m2x509 = X509.load_cert_string(self.save_to_string())
480 value = m2x509.get_ext(name).get_value()
485 # Set_data is a wrapper around add_extension. It stores the parameter str in
486 # the X509 subject_alt_name extension. Set_data can only be called once, due
487 # to limitations in the underlying library.
489 def set_data(self, str, field='subjectAltName'):
490 # pyOpenSSL only allows us to add extensions, so if we try to set the
491 # same extension more than once, it will not work
492 if self.data.has_key(field):
493 raise "Cannot set ", field, " more than once"
494 self.data[field] = str
495 self.add_extension(field, 0, str)
498 # Return the data string that was previously set with set_data
500 def get_data(self, field='subjectAltName'):
501 if self.data.has_key(field):
502 return self.data[field]
505 uri = self.get_extension(field)
506 self.data[field] = uri
510 return self.data[field]
513 # Sign the certificate using the issuer private key and issuer subject previous set with set_issuer().
516 sfa_logger().debug('certificate.sign')
517 assert self.cert != None
518 assert self.issuerSubject != None
519 assert self.issuerKey != None
520 self.cert.set_issuer(self.issuerSubject)
521 self.cert.sign(self.issuerKey.get_openssl_pkey(), self.digest)
524 # Verify the authenticity of a certificate.
525 # @param pkey is a Keypair object representing a public key. If Pkey
526 # did not sign the certificate, then an exception will be thrown.
528 def verify(self, pkey):
529 # pyOpenSSL does not have a way to verify signatures
530 m2x509 = X509.load_cert_string(self.save_to_string())
531 m2pkey = pkey.get_m2_pkey()
533 return m2x509.verify(m2pkey)
535 # XXX alternatively, if openssl has been patched, do the much simpler:
537 # self.cert.verify(pkey.get_openssl_key())
543 # Return True if pkey is identical to the public key that is contained in the certificate.
544 # @param pkey Keypair object
546 def is_pubkey(self, pkey):
547 return self.get_pubkey().is_same(pkey)
550 # Given a certificate cert, verify that this certificate was signed by the
551 # public key contained in cert. Throw an exception otherwise.
553 # @param cert certificate object
555 def is_signed_by_cert(self, cert):
556 print 'is_signed_by_cert'
557 k = cert.get_pubkey()
558 result = self.verify(k)
562 # Set the parent certficiate.
564 # @param p certificate object.
566 def set_parent(self, p):
570 # Return the certificate object of the parent of this certificate.
572 def get_parent(self):
576 # Verification examines a chain of certificates to ensure that each parent
577 # signs the child, and that some certificate in the chain is signed by a
578 # trusted certificate.
580 # Verification is a basic recursion: <pre>
581 # if this_certificate was signed by trusted_certs:
584 # return verify_chain(parent, trusted_certs)
587 # At each recursion, the parent is tested to ensure that it did sign the
588 # child. If a parent did not sign a child, then an exception is thrown. If
589 # the bottom of the recursion is reached and the certificate does not match
590 # a trusted root, then an exception is thrown.
592 # @param Trusted_certs is a list of certificates that are trusted.
595 def verify_chain(self, trusted_certs = None):
596 # Verify a chain of certificates. Each certificate must be signed by
597 # the public key contained in it's parent. The chain is recursed
598 # until a certificate is found that is signed by a trusted root.
600 # verify expiration time
601 if self.cert.has_expired():
602 sfa_logger().debug("verify_chain: NO our certificate has expired")
603 raise CertExpired(self.get_subject(), "client cert")
605 # if this cert is signed by a trusted_cert, then we are set
606 for trusted_cert in trusted_certs:
607 if self.is_signed_by_cert(trusted_cert):
608 # verify expiration of trusted_cert ?
609 if not trusted_cert.cert.has_expired():
610 sfa_logger().debug("verify_chain: YES cert %s signed by trusted cert %s"%(
611 self.get_subject(), trusted_cert.get_subject()))
614 sfa_logger().debug("verify_chain: NO cert %s is signed by trusted_cert %s, but this is expired..."%(
615 self.get_subject(),trusted_cert.get_subject()))
616 raise CertExpired(self.get_subject(),"trusted_cert %s"%trusted_cert.get_subject())
618 # if there is no parent, then no way to verify the chain
620 sfa_logger().debug("verify_chain: NO %s has no parent and is not in trusted roots"%self.get_subject())
621 raise CertMissingParent(self.get_subject())
623 # if it wasn't signed by the parent...
624 if not self.is_signed_by_cert(self.parent):
625 sfa_logger().debug("verify_chain: NO %s is not signed by parent"%self.get_subject())
626 return CertNotSignedByParent(self.get_subject())
628 # if the parent isn't verified...
629 sfa_logger().debug("verify_chain: .. %s, -> verifying parent %s",self.get_subject(),self.parent.get_subject())
630 self.parent.verify_chain(trusted_certs)
634 ### more introspection
635 def get_extensions(self):
636 # pyOpenSSL does not have a way to get extensions
638 m2x509 = X509.load_cert_string(self.save_to_string())
639 nb_extensions=m2x509.get_ext_count()
640 sfa_logger().debug("X509 had %d extensions"%nb_extensions)
641 for i in range(nb_extensions):
642 ext=m2x509.get_ext_at(i)
643 triples.append( (ext.get_name(), ext.get_value(), ext.get_critical(),) )
646 def get_data_names(self):
647 return self.data.keys()
649 def get_all_datas (self):
650 triples=self.get_extensions()
651 for name in self.get_data_names():
652 triples.append( (name,self.get_data(name),'data',) )
656 def get_filename(self):
657 return getattr(self,'filename',None)
659 def dump (self, *args, **kwargs):
660 print self.dump_string(*args, **kwargs)
662 def dump_string (self,show_extensions=False):
664 result += "CERTIFICATE for %s\n"%self.get_subject()
665 result += "Issued by %s\n"%self.get_issuer()
666 filename=self.get_filename()
667 if filename: result += "Filename %s\n"%filename
669 all_datas=self.get_all_datas()
670 result += " has %d extensions/data attached"%len(all_datas)
671 for (n,v,c) in all_datas:
673 result += " data: %s=%s\n"%(n,v)
675 result += " ext: %s (crit=%s)=<<<%s>>>\n"%(n,c,v)