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.xrn 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 # x509v3 so it can have extensions
164 # prob not necc since this cert itself is junk but still...
165 m2x509.set_version(2)
166 junk_key = Keypair(create=True)
167 m2x509.sign(pkey=junk_key.get_m2_pkey(), md="sha1")
169 # convert the m2 x509 cert to a pyopenssl x509
170 m2pem = m2x509.as_pem()
171 pyx509 = crypto.load_certificate(crypto.FILETYPE_PEM, m2pem)
173 # get the pyopenssl pkey from the pyopenssl x509
174 self.key = pyx509.get_pubkey()
175 self.filename=filename
178 # Load the public key from a string. No private key is loaded.
180 def load_pubkey_from_string(self, string):
181 (f, fn) = tempfile.mkstemp()
184 self.load_pubkey_from_file(fn)
188 # Return the private key in PEM format.
191 return crypto.dump_privatekey(crypto.FILETYPE_PEM, self.key)
194 # Return an M2Crypto key object
196 def get_m2_pkey(self):
198 self.m2key = M2Crypto.EVP.load_key_string(self.as_pem())
202 # Returns a string containing the public key represented by this object.
204 def get_pubkey_string(self):
205 m2pkey = self.get_m2_pkey()
206 return base64.b64encode(m2pkey.as_der())
209 # Return an OpenSSL pkey object
211 def get_openssl_pkey(self):
215 # Given another Keypair object, return TRUE if the two keys are the same.
217 def is_same(self, pkey):
218 return self.as_pem() == pkey.as_pem()
220 def sign_string(self, data):
221 k = self.get_m2_pkey()
224 return base64.b64encode(k.sign_final())
226 def verify_string(self, data, sig):
227 k = self.get_m2_pkey()
229 k.verify_update(data)
230 return M2Crypto.m2.verify_final(k.ctx, base64.b64decode(sig), k.pkey)
232 def compute_hash(self, value):
233 return self.sign_string(str(value))
236 def get_filename(self):
237 return getattr(self,'filename',None)
239 def dump (self, *args, **kwargs):
240 print self.dump_string(*args, **kwargs)
242 def dump_string (self):
244 result += "KEYPAIR: pubkey=%40s..."%self.get_pubkey_string()
245 filename=self.get_filename()
246 if filename: result += "Filename %s\n"%filename
250 # The certificate class implements a general purpose X509 certificate, making
251 # use of the appropriate pyOpenSSL or M2Crypto abstractions. It also adds
252 # several addition features, such as the ability to maintain a chain of
253 # parent certificates, and storage of application-specific data.
255 # Certificates include the ability to maintain a chain of parents. Each
256 # certificate includes a pointer to it's parent certificate. When loaded
257 # from a file or a string, the parent chain will be automatically loaded.
258 # When saving a certificate to a file or a string, the caller can choose
259 # whether to save the parent certificates as well.
269 separator="-----parent-----"
272 # Create a certificate object.
274 # @param create If create==True, then also create a blank X509 certificate.
275 # @param subject If subject!=None, then create a blank certificate and set
277 # @param string If string!=None, load the certficate from the string.
278 # @param filename If filename!=None, load the certficiate from the file.
280 def __init__(self, create=False, subject=None, string=None, filename=None, intermediate=None):
282 if create or subject:
285 self.set_subject(subject)
287 self.load_from_string(string)
289 self.load_from_file(filename)
292 self.set_intermediate_ca(intermediate)
295 # Create a blank X509 certificate and store it in this object.
298 self.cert = crypto.X509()
299 self.cert.set_serial_number(3)
300 self.cert.gmtime_adj_notBefore(0)
301 self.cert.gmtime_adj_notAfter(60*60*24*365*5) # five years
302 self.cert.set_version(2) # x509v3 so it can have extensions
306 # Given a pyOpenSSL X509 object, store that object inside of this
307 # certificate object.
309 def load_from_pyopenssl_x509(self, x509):
313 # Load the certificate from a string
315 def load_from_string(self, string):
316 # if it is a chain of multiple certs, then split off the first one and
317 # load it (support for the ---parent--- tag as well as normal chained certs)
319 string = string.strip()
321 # If it's not in proper PEM format, wrap it
322 if string.count('-----BEGIN CERTIFICATE') == 0:
323 string = '-----BEGIN CERTIFICATE-----\n%s\n-----END CERTIFICATE-----' % string
325 # If there is a PEM cert in there, but there is some other text first
326 # such as the text of the certificate, skip the text
327 beg = string.find('-----BEGIN CERTIFICATE')
329 # skipping over non cert beginning
330 string = string[beg:]
334 if string.count('-----BEGIN CERTIFICATE-----') > 1 and \
335 string.count(Certificate.separator) == 0:
336 parts = string.split('-----END CERTIFICATE-----',1)
337 parts[0] += '-----END CERTIFICATE-----'
339 parts = string.split(Certificate.separator, 1)
341 self.cert = crypto.load_certificate(crypto.FILETYPE_PEM, parts[0])
343 # if there are more certs, then create a parent and let the parent load
344 # itself from the remainder of the string
345 if len(parts) > 1 and parts[1] != '':
346 self.parent = self.__class__()
347 self.parent.load_from_string(parts[1])
350 # Load the certificate from a file
352 def load_from_file(self, filename):
353 file = open(filename)
355 self.load_from_string(string)
356 self.filename=filename
359 # Save the certificate to a string.
361 # @param save_parents If save_parents==True, then also save the parent certificates.
363 def save_to_string(self, save_parents=True):
364 string = crypto.dump_certificate(crypto.FILETYPE_PEM, self.cert)
365 if save_parents and self.parent:
366 string = string + self.parent.save_to_string(save_parents)
370 # Save the certificate to a file.
371 # @param save_parents If save_parents==True, then also save the parent certificates.
373 def save_to_file(self, filename, save_parents=True, filep=None):
374 string = self.save_to_string(save_parents=save_parents)
378 f = open(filename, 'w')
381 self.filename=filename
384 # Save the certificate to a random file in /tmp/
385 # @param save_parents If save_parents==True, then also save the parent certificates.
386 def save_to_random_tmp_file(self, save_parents=True):
387 fp, filename = mkstemp(suffix='cert', text=True)
388 fp = os.fdopen(fp, "w")
389 self.save_to_file(filename, save_parents=True, filep=fp)
393 # Sets the issuer private key and name
394 # @param key Keypair object containing the private key of the issuer
395 # @param subject String containing the name of the issuer
396 # @param cert (optional) Certificate object containing the name of the issuer
398 def set_issuer(self, key, subject=None, cert=None):
401 # it's a mistake to use subject and cert params at the same time
403 if isinstance(subject, dict) or isinstance(subject, str):
404 req = crypto.X509Req()
405 reqSubject = req.get_subject()
406 if (isinstance(subject, dict)):
407 for key in reqSubject.keys():
408 setattr(reqSubject, key, subject[key])
410 setattr(reqSubject, "CN", subject)
412 # subject is not valid once req is out of scope, so save req
415 # if a cert was supplied, then get the subject from the cert
416 subject = cert.cert.get_subject()
418 self.issuerSubject = subject
421 # Get the issuer name
423 def get_issuer(self, which="CN"):
424 x = self.cert.get_issuer()
425 return getattr(x, which)
428 # Set the subject name of the certificate
430 def set_subject(self, name):
431 req = crypto.X509Req()
432 subj = req.get_subject()
433 if (isinstance(name, dict)):
434 for key in name.keys():
435 setattr(subj, key, name[key])
437 setattr(subj, "CN", name)
438 self.cert.set_subject(subj)
440 # Get the subject name of the certificate
442 def get_subject(self, which="CN"):
443 x = self.cert.get_subject()
444 return getattr(x, which)
447 # Get the public key of the certificate.
449 # @param key Keypair object containing the public key
451 def set_pubkey(self, key):
452 assert(isinstance(key, Keypair))
453 self.cert.set_pubkey(key.get_openssl_pkey())
456 # Get the public key of the certificate.
457 # It is returned in the form of a Keypair object.
459 def get_pubkey(self):
460 m2x509 = X509.load_cert_string(self.save_to_string())
462 pkey.key = self.cert.get_pubkey()
463 pkey.m2key = m2x509.get_pubkey()
466 def set_intermediate_ca(self, val):
467 self.intermediate = val
469 self.add_extension('basicConstraints', 1, 'CA:TRUE')
474 # Add an X509 extension to the certificate. Add_extension can only be called
475 # once for a particular extension name, due to limitations in the underlying
478 # @param name string containing name of extension
479 # @param value string containing value of the extension
481 def add_extension(self, name, critical, value):
482 ext = crypto.X509Extension (name, critical, value)
483 self.cert.add_extensions([ext])
486 # Get an X509 extension from the certificate
488 def get_extension(self, name):
490 # pyOpenSSL does not have a way to get extensions
491 m2x509 = X509.load_cert_string(self.save_to_string())
492 value = m2x509.get_ext(name).get_value()
497 # Set_data is a wrapper around add_extension. It stores the parameter str in
498 # the X509 subject_alt_name extension. Set_data can only be called once, due
499 # to limitations in the underlying library.
501 def set_data(self, str, field='subjectAltName'):
502 # pyOpenSSL only allows us to add extensions, so if we try to set the
503 # same extension more than once, it will not work
504 if self.data.has_key(field):
505 raise "Cannot set ", field, " more than once"
506 self.data[field] = str
507 self.add_extension(field, 0, str)
510 # Return the data string that was previously set with set_data
512 def get_data(self, field='subjectAltName'):
513 if self.data.has_key(field):
514 return self.data[field]
517 uri = self.get_extension(field)
518 self.data[field] = uri
522 return self.data[field]
525 # Sign the certificate using the issuer private key and issuer subject previous set with set_issuer().
528 sfa_logger().debug('certificate.sign')
529 assert self.cert != None
530 assert self.issuerSubject != None
531 assert self.issuerKey != None
532 self.cert.set_issuer(self.issuerSubject)
533 self.cert.sign(self.issuerKey.get_openssl_pkey(), self.digest)
536 # Verify the authenticity of a certificate.
537 # @param pkey is a Keypair object representing a public key. If Pkey
538 # did not sign the certificate, then an exception will be thrown.
540 def verify(self, pkey):
541 # pyOpenSSL does not have a way to verify signatures
542 m2x509 = X509.load_cert_string(self.save_to_string())
543 m2pkey = pkey.get_m2_pkey()
545 return m2x509.verify(m2pkey)
547 # XXX alternatively, if openssl has been patched, do the much simpler:
549 # self.cert.verify(pkey.get_openssl_key())
555 # Return True if pkey is identical to the public key that is contained in the certificate.
556 # @param pkey Keypair object
558 def is_pubkey(self, pkey):
559 return self.get_pubkey().is_same(pkey)
562 # Given a certificate cert, verify that this certificate was signed by the
563 # public key contained in cert. Throw an exception otherwise.
565 # @param cert certificate object
567 def is_signed_by_cert(self, cert):
568 k = cert.get_pubkey()
569 result = self.verify(k)
573 # Set the parent certficiate.
575 # @param p certificate object.
577 def set_parent(self, p):
581 # Return the certificate object of the parent of this certificate.
583 def get_parent(self):
587 # Verification examines a chain of certificates to ensure that each parent
588 # signs the child, and that some certificate in the chain is signed by a
589 # trusted certificate.
591 # Verification is a basic recursion: <pre>
592 # if this_certificate was signed by trusted_certs:
595 # return verify_chain(parent, trusted_certs)
598 # At each recursion, the parent is tested to ensure that it did sign the
599 # child. If a parent did not sign a child, then an exception is thrown. If
600 # the bottom of the recursion is reached and the certificate does not match
601 # a trusted root, then an exception is thrown.
603 # @param Trusted_certs is a list of certificates that are trusted.
606 def verify_chain(self, trusted_certs = None):
607 # Verify a chain of certificates. Each certificate must be signed by
608 # the public key contained in it's parent. The chain is recursed
609 # until a certificate is found that is signed by a trusted root.
611 # verify expiration time
612 if self.cert.has_expired():
613 sfa_logger().debug("verify_chain: NO our certificate has expired")
614 raise CertExpired(self.get_subject(), "client cert")
616 # if this cert is signed by a trusted_cert, then we are set
617 for trusted_cert in trusted_certs:
618 if self.is_signed_by_cert(trusted_cert):
619 # verify expiration of trusted_cert ?
620 if not trusted_cert.cert.has_expired():
621 sfa_logger().debug("verify_chain: YES cert %s signed by trusted cert %s"%(
622 self.get_subject(), trusted_cert.get_subject()))
625 sfa_logger().debug("verify_chain: NO cert %s is signed by trusted_cert %s, but this is expired..."%(
626 self.get_subject(),trusted_cert.get_subject()))
627 raise CertExpired(self.get_subject(),"trusted_cert %s"%trusted_cert.get_subject())
629 # if there is no parent, then no way to verify the chain
631 sfa_logger().debug("verify_chain: NO %s has no parent and is not in trusted roots"%self.get_subject())
632 raise CertMissingParent(self.get_subject())
634 # if it wasn't signed by the parent...
635 if not self.is_signed_by_cert(self.parent):
636 sfa_logger().debug("verify_chain: NO %s is not signed by parent"%self.get_subject())
637 return CertNotSignedByParent(self.get_subject())
639 # if the parent isn't verified...
640 sfa_logger().debug("verify_chain: .. %s, -> verifying parent %s"%(self.get_subject(),self.parent.get_subject()))
641 self.parent.verify_chain(trusted_certs)
645 ### more introspection
646 def get_extensions(self):
647 # pyOpenSSL does not have a way to get extensions
649 m2x509 = X509.load_cert_string(self.save_to_string())
650 nb_extensions=m2x509.get_ext_count()
651 sfa_logger().debug("X509 had %d extensions"%nb_extensions)
652 for i in range(nb_extensions):
653 ext=m2x509.get_ext_at(i)
654 triples.append( (ext.get_name(), ext.get_value(), ext.get_critical(),) )
657 def get_data_names(self):
658 return self.data.keys()
660 def get_all_datas (self):
661 triples=self.get_extensions()
662 for name in self.get_data_names():
663 triples.append( (name,self.get_data(name),'data',) )
667 def get_filename(self):
668 return getattr(self,'filename',None)
670 def dump (self, *args, **kwargs):
671 print self.dump_string(*args, **kwargs)
673 def dump_string (self,show_extensions=False):
675 result += "CERTIFICATE for %s\n"%self.get_subject()
676 result += "Issued by %s\n"%self.get_issuer()
677 filename=self.get_filename()
678 if filename: result += "Filename %s\n"%filename
680 all_datas=self.get_all_datas()
681 result += " has %d extensions/data attached"%len(all_datas)
682 for (n,v,c) in all_datas:
684 result += " data: %s=%s\n"%(n,v)
686 result += " ext: %s (crit=%s)=<<<%s>>>\n"%(n,c,v)