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.
43 from tempfile import mkstemp
45 from OpenSSL import crypto
47 from M2Crypto import X509
49 from sfa.util.sfalogging import logger
50 from sfa.util.xrn import urn_to_hrn
51 from sfa.util.faults import *
52 from sfa.util.sfalogging import logger
54 glo_passphrase_callback = None
57 # A global callback msy be implemented for requesting passphrases from the
58 # user. The function will be called with three arguments:
60 # keypair_obj: the keypair object that is calling the passphrase
61 # string: the string containing the private key that's being loaded
62 # x: unknown, appears to be 0, comes from pyOpenSSL and/or m2crypto
64 # The callback should return a string containing the passphrase.
66 def set_passphrase_callback(callback_func):
67 global glo_passphrase_callback
69 glo_passphrase_callback = callback_func
72 # Sets a fixed passphrase.
74 def set_passphrase(passphrase):
75 set_passphrase_callback( lambda k,s,x: passphrase )
78 # Check to see if a passphrase works for a particular private key string.
79 # Intended to be used by passphrase callbacks for input validation.
81 def test_passphrase(string, passphrase):
83 crypto.load_privatekey(crypto.FILETYPE_PEM, string, (lambda x: passphrase))
88 def convert_public_key(key):
89 keyconvert_path = "/usr/bin/keyconvert.py"
90 if not os.path.isfile(keyconvert_path):
91 raise IOError, "Could not find keyconvert in %s" % keyconvert_path
93 # we can only convert rsa keys
97 (ssh_f, ssh_fn) = tempfile.mkstemp()
98 ssl_fn = tempfile.mktemp()
102 cmd = keyconvert_path + " " + ssh_fn + " " + ssl_fn
105 # this check leaves the temporary file containing the public key so
106 # that it can be expected to see why it failed.
107 # TODO: for production, cleanup the temporary files
108 if not os.path.exists(ssl_fn):
113 k.load_pubkey_from_file(ssl_fn)
115 logger.log_exc("convert_public_key caught exception")
118 # remove the temporary files
125 # Public-private key pairs are implemented by the Keypair class.
126 # A Keypair object may represent both a public and private key pair, or it
127 # may represent only a public key (this usage is consistent with OpenSSL).
130 key = None # public/private keypair
131 m2key = None # public key (m2crypto format)
134 # Creates a Keypair object
135 # @param create If create==True, creates a new public/private key and
136 # stores it in the object
137 # @param string If string!=None, load the keypair from the string (PEM)
138 # @param filename If filename!=None, load the keypair from the file
140 def __init__(self, create=False, string=None, filename=None):
144 self.load_from_string(string)
146 self.load_from_file(filename)
149 # Create a RSA public/private key pair and store it inside the keypair object
152 self.key = crypto.PKey()
153 self.key.generate_key(crypto.TYPE_RSA, 1024)
156 # Save the private key to a file
157 # @param filename name of file to store the keypair in
159 def save_to_file(self, filename):
160 open(filename, 'w').write(self.as_pem())
161 self.filename=filename
164 # Load the private key from a file. Implicity the private key includes the public key.
166 def load_from_file(self, filename):
167 self.filename=filename
168 buffer = open(filename, 'r').read()
169 self.load_from_string(buffer)
172 # Load the private key from a string. Implicitly the private key includes the public key.
174 def load_from_string(self, string):
175 if glo_passphrase_callback:
176 self.key = crypto.load_privatekey(crypto.FILETYPE_PEM, string, functools.partial(glo_passphrase_callback, self, string) )
177 self.m2key = M2Crypto.EVP.load_key_string(string, functools.partial(glo_passphrase_callback, self, string) )
179 self.key = crypto.load_privatekey(crypto.FILETYPE_PEM, string)
180 self.m2key = M2Crypto.EVP.load_key_string(string)
183 # Load the public key from a string. No private key is loaded.
185 def load_pubkey_from_file(self, filename):
186 # load the m2 public key
187 m2rsakey = M2Crypto.RSA.load_pub_key(filename)
188 self.m2key = M2Crypto.EVP.PKey()
189 self.m2key.assign_rsa(m2rsakey)
191 # create an m2 x509 cert
192 m2name = M2Crypto.X509.X509_Name()
193 m2name.add_entry_by_txt(field="CN", type=0x1001, entry="junk", len=-1, loc=-1, set=0)
194 m2x509 = M2Crypto.X509.X509()
195 m2x509.set_pubkey(self.m2key)
196 m2x509.set_serial_number(0)
197 m2x509.set_issuer_name(m2name)
198 m2x509.set_subject_name(m2name)
199 ASN1 = M2Crypto.ASN1.ASN1_UTCTIME()
201 m2x509.set_not_before(ASN1)
202 m2x509.set_not_after(ASN1)
203 # x509v3 so it can have extensions
204 # prob not necc since this cert itself is junk but still...
205 m2x509.set_version(2)
206 junk_key = Keypair(create=True)
207 m2x509.sign(pkey=junk_key.get_m2_pkey(), md="sha1")
209 # convert the m2 x509 cert to a pyopenssl x509
210 m2pem = m2x509.as_pem()
211 pyx509 = crypto.load_certificate(crypto.FILETYPE_PEM, m2pem)
213 # get the pyopenssl pkey from the pyopenssl x509
214 self.key = pyx509.get_pubkey()
215 self.filename=filename
218 # Load the public key from a string. No private key is loaded.
220 def load_pubkey_from_string(self, string):
221 (f, fn) = tempfile.mkstemp()
224 self.load_pubkey_from_file(fn)
228 # Return the private key in PEM format.
231 return crypto.dump_privatekey(crypto.FILETYPE_PEM, self.key)
234 # Return an M2Crypto key object
236 def get_m2_pkey(self):
238 self.m2key = M2Crypto.EVP.load_key_string(self.as_pem())
242 # Returns a string containing the public key represented by this object.
244 def get_pubkey_string(self):
245 m2pkey = self.get_m2_pkey()
246 return base64.b64encode(m2pkey.as_der())
249 # Return an OpenSSL pkey object
251 def get_openssl_pkey(self):
255 # Given another Keypair object, return TRUE if the two keys are the same.
257 def is_same(self, pkey):
258 return self.as_pem() == pkey.as_pem()
260 def sign_string(self, data):
261 k = self.get_m2_pkey()
264 return base64.b64encode(k.sign_final())
266 def verify_string(self, data, sig):
267 k = self.get_m2_pkey()
269 k.verify_update(data)
270 return M2Crypto.m2.verify_final(k.ctx, base64.b64decode(sig), k.pkey)
272 def compute_hash(self, value):
273 return self.sign_string(str(value))
276 def get_filename(self):
277 return getattr(self,'filename',None)
279 def dump (self, *args, **kwargs):
280 print self.dump_string(*args, **kwargs)
282 def dump_string (self):
284 result += "KEYPAIR: pubkey=%40s..."%self.get_pubkey_string()
285 filename=self.get_filename()
286 if filename: result += "Filename %s\n"%filename
290 # The certificate class implements a general purpose X509 certificate, making
291 # use of the appropriate pyOpenSSL or M2Crypto abstractions. It also adds
292 # several addition features, such as the ability to maintain a chain of
293 # parent certificates, and storage of application-specific data.
295 # Certificates include the ability to maintain a chain of parents. Each
296 # certificate includes a pointer to it's parent certificate. When loaded
297 # from a file or a string, the parent chain will be automatically loaded.
298 # When saving a certificate to a file or a string, the caller can choose
299 # whether to save the parent certificates as well.
308 isCA = None # will be a boolean once set
310 separator="-----parent-----"
313 # Create a certificate object.
315 # @param lifeDays life of cert in days - default is 1825==5 years
316 # @param create If create==True, then also create a blank X509 certificate.
317 # @param subject If subject!=None, then create a blank certificate and set
319 # @param string If string!=None, load the certficate from the string.
320 # @param filename If filename!=None, load the certficiate from the file.
321 # @param isCA If !=None, set whether this cert is for a CA
323 def __init__(self, lifeDays=1825, create=False, subject=None, string=None, filename=None, isCA=None):
325 if create or subject:
326 self.create(lifeDays)
328 self.set_subject(subject)
330 self.load_from_string(string)
332 self.load_from_file(filename)
334 # Set the CA bit if a value was supplied
338 # Create a blank X509 certificate and store it in this object.
340 def create(self, lifeDays=1825):
341 self.cert = crypto.X509()
342 # FIXME: Use different serial #s
343 self.cert.set_serial_number(3)
344 self.cert.gmtime_adj_notBefore(0) # 0 means now
345 self.cert.gmtime_adj_notAfter(lifeDays*60*60*24) # five years is default
346 self.cert.set_version(2) # x509v3 so it can have extensions
350 # Given a pyOpenSSL X509 object, store that object inside of this
351 # certificate object.
353 def load_from_pyopenssl_x509(self, x509):
357 # Load the certificate from a string
359 def load_from_string(self, string):
360 # if it is a chain of multiple certs, then split off the first one and
361 # load it (support for the ---parent--- tag as well as normal chained certs)
363 string = string.strip()
365 # If it's not in proper PEM format, wrap it
366 if string.count('-----BEGIN CERTIFICATE') == 0:
367 string = '-----BEGIN CERTIFICATE-----\n%s\n-----END CERTIFICATE-----' % string
369 # If there is a PEM cert in there, but there is some other text first
370 # such as the text of the certificate, skip the text
371 beg = string.find('-----BEGIN CERTIFICATE')
373 # skipping over non cert beginning
374 string = string[beg:]
378 if string.count('-----BEGIN CERTIFICATE-----') > 1 and \
379 string.count(Certificate.separator) == 0:
380 parts = string.split('-----END CERTIFICATE-----',1)
381 parts[0] += '-----END CERTIFICATE-----'
383 parts = string.split(Certificate.separator, 1)
385 self.cert = crypto.load_certificate(crypto.FILETYPE_PEM, parts[0])
387 # if there are more certs, then create a parent and let the parent load
388 # itself from the remainder of the string
389 if len(parts) > 1 and parts[1] != '':
390 self.parent = self.__class__()
391 self.parent.load_from_string(parts[1])
394 # Load the certificate from a file
396 def load_from_file(self, filename):
397 file = open(filename)
399 self.load_from_string(string)
400 self.filename=filename
403 # Save the certificate to a string.
405 # @param save_parents If save_parents==True, then also save the parent certificates.
407 def save_to_string(self, save_parents=True):
408 string = crypto.dump_certificate(crypto.FILETYPE_PEM, self.cert)
409 if save_parents and self.parent:
410 string = string + self.parent.save_to_string(save_parents)
414 # Save the certificate to a file.
415 # @param save_parents If save_parents==True, then also save the parent certificates.
417 def save_to_file(self, filename, save_parents=True, filep=None):
418 string = self.save_to_string(save_parents=save_parents)
422 f = open(filename, 'w')
425 self.filename=filename
428 # Save the certificate to a random file in /tmp/
429 # @param save_parents If save_parents==True, then also save the parent certificates.
430 def save_to_random_tmp_file(self, save_parents=True):
431 fp, filename = mkstemp(suffix='cert', text=True)
432 fp = os.fdopen(fp, "w")
433 self.save_to_file(filename, save_parents=True, filep=fp)
437 # Sets the issuer private key and name
438 # @param key Keypair object containing the private key of the issuer
439 # @param subject String containing the name of the issuer
440 # @param cert (optional) Certificate object containing the name of the issuer
442 def set_issuer(self, key, subject=None, cert=None):
445 # it's a mistake to use subject and cert params at the same time
447 if isinstance(subject, dict) or isinstance(subject, str):
448 req = crypto.X509Req()
449 reqSubject = req.get_subject()
450 if (isinstance(subject, dict)):
451 for key in reqSubject.keys():
452 setattr(reqSubject, key, subject[key])
454 setattr(reqSubject, "CN", subject)
456 # subject is not valid once req is out of scope, so save req
459 # if a cert was supplied, then get the subject from the cert
460 subject = cert.cert.get_subject()
462 self.issuerSubject = subject
465 # Get the issuer name
467 def get_issuer(self, which="CN"):
468 x = self.cert.get_issuer()
469 return getattr(x, which)
472 # Set the subject name of the certificate
474 def set_subject(self, name):
475 req = crypto.X509Req()
476 subj = req.get_subject()
477 if (isinstance(name, dict)):
478 for key in name.keys():
479 setattr(subj, key, name[key])
481 setattr(subj, "CN", name)
482 self.cert.set_subject(subj)
485 # Get the subject name of the certificate
487 def get_subject(self, which="CN"):
488 x = self.cert.get_subject()
489 return getattr(x, which)
492 # Get a pretty-print subject name of the certificate
494 def get_printable_subject(self):
495 x = self.cert.get_subject()
496 return "[ OU: %s, CN: %s, SubjectAltName: %s ]" % (getattr(x, "OU"), getattr(x, "CN"), self.get_data())
499 # Get the public key of the certificate.
501 # @param key Keypair object containing the public key
503 def set_pubkey(self, key):
504 assert(isinstance(key, Keypair))
505 self.cert.set_pubkey(key.get_openssl_pkey())
508 # Get the public key of the certificate.
509 # It is returned in the form of a Keypair object.
511 def get_pubkey(self):
512 m2x509 = X509.load_cert_string(self.save_to_string())
514 pkey.key = self.cert.get_pubkey()
515 pkey.m2key = m2x509.get_pubkey()
518 def set_intermediate_ca(self, val):
519 return self.set_is_ca(val)
521 # Set whether this cert is for a CA. All signers and only signers should be CAs.
522 # The local member starts unset, letting us check that you only set it once
523 # @param val Boolean indicating whether this cert is for a CA
524 def set_is_ca(self, val):
528 if self.isCA != None:
529 # Can't double set properties
530 raise "Cannot set basicConstraints CA:?? more than once. Was %s, trying to set as %s" % (self.isCA, val)
534 self.add_extension('basicConstraints', 1, 'CA:TRUE')
536 self.add_extension('basicConstraints', 1, 'CA:FALSE')
541 # Add an X509 extension to the certificate. Add_extension can only be called
542 # once for a particular extension name, due to limitations in the underlying
545 # @param name string containing name of extension
546 # @param value string containing value of the extension
548 def add_extension(self, name, critical, value):
551 oldExtVal = self.get_extension(name)
553 # M2Crypto LookupError when the extension isn't there (yet)
556 # This code limits you from adding the extension with the same value
557 # The method comment says you shouldn't do this with the same name
558 # But actually it (m2crypto) appears to allow you to do this.
559 if oldExtVal and oldExtVal == value:
560 # don't add this extension again
561 # just do nothing as here
563 # FIXME: What if they are trying to set with a different value?
564 # Is this ever OK? Or should we raise an exception?
566 # raise "Cannot add extension %s which had val %s with new val %s" % (name, oldExtVal, value)
568 ext = crypto.X509Extension (name, critical, value)
569 self.cert.add_extensions([ext])
572 # Get an X509 extension from the certificate
574 def get_extension(self, name):
576 # pyOpenSSL does not have a way to get extensions
577 m2x509 = X509.load_cert_string(self.save_to_string())
578 value = m2x509.get_ext(name).get_value()
583 # Set_data is a wrapper around add_extension. It stores the parameter str in
584 # the X509 subject_alt_name extension. Set_data can only be called once, due
585 # to limitations in the underlying library.
587 def set_data(self, str, field='subjectAltName'):
588 # pyOpenSSL only allows us to add extensions, so if we try to set the
589 # same extension more than once, it will not work
590 if self.data.has_key(field):
591 raise "Cannot set ", field, " more than once"
592 self.data[field] = str
593 self.add_extension(field, 0, str)
596 # Return the data string that was previously set with set_data
598 def get_data(self, field='subjectAltName'):
599 if self.data.has_key(field):
600 return self.data[field]
603 uri = self.get_extension(field)
604 self.data[field] = uri
608 return self.data[field]
611 # Sign the certificate using the issuer private key and issuer subject previous set with set_issuer().
614 logger.debug('certificate.sign')
615 assert self.cert != None
616 assert self.issuerSubject != None
617 assert self.issuerKey != None
618 self.cert.set_issuer(self.issuerSubject)
619 self.cert.sign(self.issuerKey.get_openssl_pkey(), self.digest)
622 # Verify the authenticity of a certificate.
623 # @param pkey is a Keypair object representing a public key. If Pkey
624 # did not sign the certificate, then an exception will be thrown.
626 def verify(self, pkey):
627 # pyOpenSSL does not have a way to verify signatures
628 m2x509 = X509.load_cert_string(self.save_to_string())
629 m2pkey = pkey.get_m2_pkey()
631 return m2x509.verify(m2pkey)
633 # XXX alternatively, if openssl has been patched, do the much simpler:
635 # self.cert.verify(pkey.get_openssl_key())
641 # Return True if pkey is identical to the public key that is contained in the certificate.
642 # @param pkey Keypair object
644 def is_pubkey(self, pkey):
645 return self.get_pubkey().is_same(pkey)
648 # Given a certificate cert, verify that this certificate was signed by the
649 # public key contained in cert. Throw an exception otherwise.
651 # @param cert certificate object
653 def is_signed_by_cert(self, cert):
654 k = cert.get_pubkey()
655 result = self.verify(k)
659 # Set the parent certficiate.
661 # @param p certificate object.
663 def set_parent(self, p):
667 # Return the certificate object of the parent of this certificate.
669 def get_parent(self):
673 # Verification examines a chain of certificates to ensure that each parent
674 # signs the child, and that some certificate in the chain is signed by a
675 # trusted certificate.
677 # Verification is a basic recursion: <pre>
678 # if this_certificate was signed by trusted_certs:
681 # return verify_chain(parent, trusted_certs)
684 # At each recursion, the parent is tested to ensure that it did sign the
685 # child. If a parent did not sign a child, then an exception is thrown. If
686 # the bottom of the recursion is reached and the certificate does not match
687 # a trusted root, then an exception is thrown.
688 # Also require that parents are CAs.
690 # @param Trusted_certs is a list of certificates that are trusted.
693 def verify_chain(self, trusted_certs = None):
694 # Verify a chain of certificates. Each certificate must be signed by
695 # the public key contained in it's parent. The chain is recursed
696 # until a certificate is found that is signed by a trusted root.
698 # verify expiration time
699 if self.cert.has_expired():
700 logger.debug("verify_chain: NO our certificate %s has expired" % self.get_printable_subject())
701 raise CertExpired(self.get_printable_subject(), "client cert")
703 # if this cert is signed by a trusted_cert, then we are set
704 for trusted_cert in trusted_certs:
705 if self.is_signed_by_cert(trusted_cert):
706 # verify expiration of trusted_cert ?
707 if not trusted_cert.cert.has_expired():
708 logger.debug("verify_chain: YES cert %s signed by trusted cert %s"%(
709 self.get_printable_subject(), trusted_cert.get_printable_subject()))
712 logger.debug("verify_chain: NO cert %s is signed by trusted_cert %s, but this is expired..."%(
713 self.get_printable_subject(),trusted_cert.get_printable_subject()))
714 raise CertExpired(self.get_printable_subject()," signer trusted_cert %s"%trusted_cert.get_printable_subject())
716 # if there is no parent, then no way to verify the chain
718 logger.debug("verify_chain: NO %s has no parent and issuer %s is not in %d trusted roots"%self.get_printable_subject(), self.get_issuer(), len(trusted_certs))
719 raise CertMissingParent(self.get_printable_subject(), "Non trusted issuer: %s out of %d trusted roots" % (self.get_issuer(), len(trusted_certs)))
721 # if it wasn't signed by the parent...
722 if not self.is_signed_by_cert(self.parent):
723 logger.debug("verify_chain: NO %s is not signed by parent %s, but by %s"%self.get_printable_subject(), self.parent.get_printable_subject(), self.get_issuer())
724 return CertNotSignedByParent(self.get_printable_subject(), "parent %s, issuer %s" % (selr.parent.get_printable_subject(), self.get_issuer()))
726 # Confirm that the parent is a CA. Only CAs can be trusted as
728 # Note that trusted roots are not parents, so don't need to be
730 # Ugly - cert objects aren't parsed so we need to read the
731 # extension and hope there are no other basicConstraints
732 if not self.parent.isCA and not (self.parent.get_extension('basicConstraints') == 'CA:TRUE'):
733 logger.warn("verify_chain: cert %s's parent %s is not a CA" % (self.get_printable_subject(), self.parent.get_printable_subject()))
734 return CertNotSignedByParent(self.get_printable_subject(), "Parent %s not a CA" % self.parent.get_printable_subject())
736 # if the parent isn't verified...
737 logger.debug("verify_chain: .. %s, -> verifying parent %s"%(self.get_printable_subject(),self.parent.get_printable_subject()))
738 self.parent.verify_chain(trusted_certs)
742 ### more introspection
743 def get_extensions(self):
744 # pyOpenSSL does not have a way to get extensions
746 m2x509 = X509.load_cert_string(self.save_to_string())
747 nb_extensions=m2x509.get_ext_count()
748 logger.debug("X509 had %d extensions"%nb_extensions)
749 for i in range(nb_extensions):
750 ext=m2x509.get_ext_at(i)
751 triples.append( (ext.get_name(), ext.get_value(), ext.get_critical(),) )
754 def get_data_names(self):
755 return self.data.keys()
757 def get_all_datas (self):
758 triples=self.get_extensions()
759 for name in self.get_data_names():
760 triples.append( (name,self.get_data(name),'data',) )
764 def get_filename(self):
765 return getattr(self,'filename',None)
767 def dump (self, *args, **kwargs):
768 print self.dump_string(*args, **kwargs)
770 def dump_string (self,show_extensions=False):
772 result += "CERTIFICATE for %s\n"%self.get_printable_subject()
773 result += "Issued by %s\n"%self.get_issuer()
774 filename=self.get_filename()
775 if filename: result += "Filename %s\n"%filename
777 all_datas=self.get_all_datas()
778 result += " has %d extensions/data attached"%len(all_datas)
779 for (n,v,c) in all_datas:
781 result += " data: %s=%s\n"%(n,v)
783 result += " ext: %s (crit=%s)=<<<%s>>>\n"%(n,c,v)