2 # Geniwrapper uses two crypto libraries: pyOpenSSL and M2Crypto to implement
3 # the necessary crypto functionality. Ideally just one of these libraries
4 # would be used, but unfortunately each of these libraries is independently
5 # lacking. The pyOpenSSL library is missing many necessary functions, and
6 # the M2Crypto library has crashed inside of some of the functions. The
7 # design decision is to use pyOpenSSL whenever possible as it seems more
8 # stable, and only use M2Crypto for those functions that are not possible
11 # This module exports two classes: Keypair and Certificate.
22 from OpenSSL import crypto
24 from M2Crypto import X509
25 from M2Crypto import EVP
27 from sfa.util.faults import *
29 def convert_public_key(key):
30 keyconvert_path = "/usr/bin/keyconvert"
31 if not os.path.isfile(keyconvert_path):
32 raise IOError, "Could not find keyconvert in %s" % keyconvert_path
34 # we can only convert rsa keys
36 print "XXX: DSA key encountered, ignoring"
39 (ssh_f, ssh_fn) = tempfile.mkstemp()
40 ssl_fn = tempfile.mktemp()
44 cmd = keyconvert_path + " " + ssh_fn + " " + ssl_fn
47 # this check leaves the temporary file containing the public key so
48 # that it can be expected to see why it failed.
49 # TODO: for production, cleanup the temporary files
50 if not os.path.exists(ssl_fn):
51 report.trace(" failed to convert key from " + ssh_fn + " to " + ssl_fn)
56 k.load_pubkey_from_file(ssl_fn)
58 print "XXX: Error while converting key: ", key
62 # remove the temporary files
69 # Public-private key pairs are implemented by the Keypair class.
70 # A Keypair object may represent both a public and private key pair, or it
71 # may represent only a public key (this usage is consistent with OpenSSL).
74 key = None # public/private keypair
75 m2key = None # public key (m2crypto format)
78 # Creates a Keypair object
79 # @param create If create==True, creates a new public/private key and
80 # stores it in the object
81 # @param string If string!=None, load the keypair from the string (PEM)
82 # @param filename If filename!=None, load the keypair from the file
84 def __init__(self, create=False, string=None, filename=None):
88 self.load_from_string(string)
90 self.load_from_file(filename)
93 # Create a RSA public/private key pair and store it inside the keypair object
96 self.key = crypto.PKey()
97 self.key.generate_key(crypto.TYPE_RSA, 1024)
100 # Save the private key to a file
101 # @param filename name of file to store the keypair in
103 def save_to_file(self, filename):
104 open(filename, 'w').write(self.as_pem())
107 # Load the private key from a file. Implicity the private key includes the public key.
109 def load_from_file(self, filename):
110 buffer = open(filename, 'r').read()
111 self.load_from_string(buffer)
114 # Load the private key from a string. Implicitly the private key includes the public key.
116 def load_from_string(self, string):
117 self.key = crypto.load_privatekey(crypto.FILETYPE_PEM, string)
118 self.m2key = M2Crypto.EVP.load_key_string(string)
121 # Load the public key from a string. No private key is loaded.
123 def load_pubkey_from_file(self, filename):
124 # load the m2 public key
125 m2rsakey = M2Crypto.RSA.load_pub_key(filename)
126 self.m2key = M2Crypto.EVP.PKey()
127 self.m2key.assign_rsa(m2rsakey)
129 # create an m2 x509 cert
130 m2name = M2Crypto.X509.X509_Name()
131 m2name.add_entry_by_txt(field="CN", type=0x1001, entry="junk", len=-1, loc=-1, set=0)
132 m2x509 = M2Crypto.X509.X509()
133 m2x509.set_pubkey(self.m2key)
134 m2x509.set_serial_number(0)
135 m2x509.set_issuer_name(m2name)
136 m2x509.set_subject_name(m2name)
137 ASN1 = M2Crypto.ASN1.ASN1_UTCTIME()
139 m2x509.set_not_before(ASN1)
140 m2x509.set_not_after(ASN1)
141 junk_key = Keypair(create=True)
142 m2x509.sign(pkey=junk_key.get_m2_pkey(), md="sha1")
144 # convert the m2 x509 cert to a pyopenssl x509
145 m2pem = m2x509.as_pem()
146 pyx509 = crypto.load_certificate(crypto.FILETYPE_PEM, m2pem)
148 # get the pyopenssl pkey from the pyopenssl x509
149 self.key = pyx509.get_pubkey()
152 # Load the public key from a string. No private key is loaded.
154 def load_pubkey_from_string(self, string):
155 (f, fn) = tempfile.mkstemp()
158 self.load_pubkey_from_file(fn)
162 # Return the private key in PEM format.
165 return crypto.dump_privatekey(crypto.FILETYPE_PEM, self.key)
168 # Return an M2Crypto key object
170 def get_m2_pkey(self):
172 self.m2key = M2Crypto.EVP.load_key_string(self.as_pem())
176 # Returns a string containing the public key represented by this object.
178 def get_pubkey_string(self):
179 m2pkey = self.get_m2_pkey()
180 return base64.b64encode(m2pkey.as_der())
183 # Return an OpenSSL pkey object
185 def get_openssl_pkey(self):
189 # Given another Keypair object, return TRUE if the two keys are the same.
191 def is_same(self, pkey):
192 return self.as_pem() == pkey.as_pem()
194 def sign_string(self, data):
195 k = self.get_m2_pkey()
198 return base64.b64encode(k.sign_final())
200 def verify_string(self, data, sig):
201 k = self.get_m2_pkey()
203 k.verify_update(data)
204 return M2Crypto.m2.verify_final(k.ctx, base64.b64decode(sig), k.pkey)
206 def compute_hash(self, value):
207 return self.sign_string(str(value))
210 # The certificate class implements a general purpose X509 certificate, making
211 # use of the appropriate pyOpenSSL or M2Crypto abstractions. It also adds
212 # several addition features, such as the ability to maintain a chain of
213 # parent certificates, and storage of application-specific data.
215 # Certificates include the ability to maintain a chain of parents. Each
216 # certificate includes a pointer to it's parent certificate. When loaded
217 # from a file or a string, the parent chain will be automatically loaded.
218 # When saving a certificate to a file or a string, the caller can choose
219 # whether to save the parent certificates as well.
230 separator="-----parent-----"
233 # Create a certificate object.
235 # @param create If create==True, then also create a blank X509 certificate.
236 # @param subject If subject!=None, then create a blank certificate and set
238 # @param string If string!=None, load the certficate from the string.
239 # @param filename If filename!=None, load the certficiate from the file.
241 def __init__(self, create=False, subject=None, string=None, filename=None):
242 if create or subject:
245 self.set_subject(subject)
247 self.load_from_string(string)
249 self.load_from_file(filename)
252 # Create a blank X509 certificate and store it in this object.
255 self.cert = crypto.X509()
256 self.cert.set_serial_number(1)
257 self.cert.gmtime_adj_notBefore(0)
258 self.cert.gmtime_adj_notAfter(60*60*24*365*5) # five years
261 # Given a pyOpenSSL X509 object, store that object inside of this
262 # certificate object.
264 def load_from_pyopenssl_x509(self, x509):
268 # Load the certificate from a string
270 def load_from_string(self, string):
271 # if it is a chain of multiple certs, then split off the first one and
273 parts = string.split(Certificate.separator, 1)
274 self.cert = crypto.load_certificate(crypto.FILETYPE_PEM, parts[0])
276 # if there are more certs, then create a parent and let the parent load
277 # itself from the remainder of the string
279 self.parent = self.__class__()
280 self.parent.load_from_string(parts[1])
283 # Load the certificate from a file
285 def load_from_file(self, filename):
286 file = open(filename)
288 self.load_from_string(string)
291 # Save the certificate to a string.
293 # @param save_parents If save_parents==True, then also save the parent certificates.
295 def save_to_string(self, save_parents=False):
296 string = crypto.dump_certificate(crypto.FILETYPE_PEM, self.cert)
297 if save_parents and self.parent:
298 string = string + Certificate.separator + self.parent.save_to_string(save_parents)
302 # Save the certificate to a file.
303 # @param save_parents If save_parents==True, then also save the parent certificates.
305 def save_to_file(self, filename, save_parents=False):
306 string = self.save_to_string(save_parents=save_parents)
307 open(filename, 'w').write(string)
310 # Sets the issuer private key and name
311 # @param key Keypair object containing the private key of the issuer
312 # @param subject String containing the name of the issuer
313 # @param cert (optional) Certificate object containing the name of the issuer
315 def set_issuer(self, key, subject=None, cert=None):
318 # it's a mistake to use subject and cert params at the same time
320 if isinstance(subject, dict) or isinstance(subject, str):
321 req = crypto.X509Req()
322 reqSubject = req.get_subject()
323 if (isinstance(subject, dict)):
324 for key in reqSubject.keys():
325 setattr(reqSubject, key, name[key])
327 setattr(reqSubject, "CN", subject)
329 # subject is not valid once req is out of scope, so save req
332 # if a cert was supplied, then get the subject from the cert
333 subject = cert.cert.get_issuer()
335 self.issuerSubject = subject
338 # Get the issuer name
340 def get_issuer(self, which="CN"):
341 x = self.cert.get_issuer()
342 return getattr(x, which)
345 # Set the subject name of the certificate
347 def set_subject(self, name):
348 req = crypto.X509Req()
349 subj = req.get_subject()
350 if (isinstance(name, dict)):
351 for key in name.keys():
352 setattr(subj, key, name[key])
354 setattr(subj, "CN", name)
355 self.cert.set_subject(subj)
357 # Get the subject name of the certificate
359 def get_subject(self, which="CN"):
360 x = self.cert.get_subject()
361 return getattr(x, which)
364 # Get the public key of the certificate.
366 # @param key Keypair object containing the public key
368 def set_pubkey(self, key):
369 assert(isinstance(key, Keypair))
370 self.cert.set_pubkey(key.get_openssl_pkey())
373 # Get the public key of the certificate.
374 # It is returned in the form of a Keypair object.
376 def get_pubkey(self):
377 m2x509 = X509.load_cert_string(self.save_to_string())
379 pkey.key = self.cert.get_pubkey()
380 pkey.m2key = m2x509.get_pubkey()
384 # Add an X509 extension to the certificate. Add_extension can only be called
385 # once for a particular extension name, due to limitations in the underlying
388 # @param name string containing name of extension
389 # @param value string containing value of the extension
391 def add_extension(self, name, critical, value):
392 ext = crypto.X509Extension (name, critical, value)
393 self.cert.add_extensions([ext])
396 # Get an X509 extension from the certificate
398 def get_extension(self, name):
399 # pyOpenSSL does not have a way to get extensions
400 m2x509 = X509.load_cert_string(self.save_to_string())
401 value = m2x509.get_ext(name).get_value()
405 # Set_data is a wrapper around add_extension. It stores the parameter str in
406 # the X509 subject_alt_name extension. Set_data can only be called once, due
407 # to limitations in the underlying library.
409 def set_data(self, str):
410 # pyOpenSSL only allows us to add extensions, so if we try to set the
411 # same extension more than once, it will not work
412 if self.data != None:
413 raise "cannot set subjectAltName more than once"
415 self.add_extension("subjectAltName", 0, "URI:http://" + str)
418 # Return the data string that was previously set with set_data
425 uri = self.get_extension("subjectAltName")
430 if not uri.startswith("URI:http://"):
431 raise "bad encoding in subjectAltName"
436 # Sign the certificate using the issuer private key and issuer subject previous set with set_issuer().
439 assert self.cert != None
440 assert self.issuerSubject != None
441 assert self.issuerKey != None
442 self.cert.set_issuer(self.issuerSubject)
443 self.cert.sign(self.issuerKey.get_openssl_pkey(), self.digest)
446 # Verify the authenticity of a certificate.
447 # @param pkey is a Keypair object representing a public key. If Pkey
448 # did not sign the certificate, then an exception will be thrown.
450 def verify(self, pkey):
451 # pyOpenSSL does not have a way to verify signatures
452 m2x509 = X509.load_cert_string(self.save_to_string())
453 m2pkey = pkey.get_m2_pkey()
455 return m2x509.verify(m2pkey)
457 # XXX alternatively, if openssl has been patched, do the much simpler:
459 # self.cert.verify(pkey.get_openssl_key())
465 # Return True if pkey is identical to the public key that is contained in the certificate.
466 # @param pkey Keypair object
468 def is_pubkey(self, pkey):
469 return self.get_pubkey().is_same(pkey)
472 # Given a certificate cert, verify that this certificate was signed by the
473 # public key contained in cert. Throw an exception otherwise.
475 # @param cert certificate object
477 def is_signed_by_cert(self, cert):
478 k = cert.get_pubkey()
479 result = self.verify(k)
483 # Set the parent certficiate.
485 # @param p certificate object.
487 def set_parent(self, p):
491 # Return the certificate object of the parent of this certificate.
493 def get_parent(self):
497 # Verification examines a chain of certificates to ensure that each parent
498 # signs the child, and that some certificate in the chain is signed by a
499 # trusted certificate.
501 # Verification is a basic recursion: <pre>
502 # if this_certificate was signed by trusted_certs:
505 # return verify_chain(parent, trusted_certs)
508 # At each recursion, the parent is tested to ensure that it did sign the
509 # child. If a parent did not sign a child, then an exception is thrown. If
510 # the bottom of the recursion is reached and the certificate does not match
511 # a trusted root, then an exception is thrown.
513 # @param Trusted_certs is a list of certificates that are trusted.
516 def verify_chain(self, trusted_certs = None):
517 # Verify a chain of certificates. Each certificate must be signed by
518 # the public key contained in it's parent. The chain is recursed
519 # until a certificate is found that is signed by a trusted root.
521 # TODO: verify expiration time
522 #print "====Verify Chain====="
523 # if this cert is signed by a trusted_cert, then we are set
524 for trusted_cert in trusted_certs:
525 #print "***************"
526 # TODO: verify expiration of trusted_cert ?
527 #print "CLIENT CERT", self.dump()
528 #print "TRUSTED CERT", trusted_cert.dump()
529 #print "Client is signed by Trusted?", self.is_signed_by_cert(trusted_cert)
530 if self.is_signed_by_cert(trusted_cert):
531 #print self.get_subject(), "is signed by a root"
534 # if there is no parent, then no way to verify the chain
536 #print self.get_subject(), "has no parent"
537 raise CertMissingParent(self.get_subject())
539 # if it wasn't signed by the parent...
540 if not self.is_signed_by_cert(self.parent):
541 #print self.get_subject(), "is not signed by parent"
542 return CertNotSignedByParent(self.get_subject())
544 # if the parent isn't verified...
545 self.parent.verify_chain(trusted_certs)