1 # Thierry Parmentelat -- INRIA
3 # a minimal library for writing "lightweight" SFA clients
7 # this library should probably check for the expiration date of the various
8 # certificates and automatically retrieve fresh ones when expired
13 from datetime import datetime
14 from sfa.util.xrn import Xrn
16 import sfa.util.sfalogging
17 # importing sfa.utils.faults does pull a lot of stuff
18 # OTOH it's imported from Certificate anyways, so..
19 from sfa.util.faults import RecordNotFound
21 from sfa.client.sfaserverproxy import SfaServerProxy
23 # see optimizing dependencies below
24 from sfa.trust.certificate import Keypair, Certificate
25 from sfa.trust.credential import Credential
26 from sfa.trust.gid import GID
28 # a helper class to implement the bootstrapping of cryptoa. material
29 # assuming we are starting from scratch on the client side
30 # what's needed to complete a full slice creation cycle
32 # (*) a local private key
33 # (*) the corresp. public key in the registry
34 # (**) step1: a self-signed certificate
35 # default filename is <hrn>.sscert
36 # (**) step2: a user credential
37 # obtained at the registry with GetSelfCredential
38 # using the self-signed certificate as the SSL cert
39 # default filename is <hrn>.user.cred
40 # (**) step3: a registry-provided certificate (i.e. a GID)
41 # obtained at the registry using Resolve
42 # using the step2 credential as credential
43 # default filename is <hrn>.user.gid
45 # From that point on, the GID is used as the SSL certificate
46 # and the following can be done
48 # (**) retrieve a slice (or authority) credential
49 # obtained at the registry with GetCredential
50 # using the (step2) user-credential as credential
51 # default filename is <hrn>.<type>.cred
52 # (**) retrieve a slice (or authority) GID
53 # obtained at the registry with Resolve
54 # using the (step2) user-credential as credential
55 # default filename is <hrn>.<type>.cred
57 # (**) additionnally, it might make sense to upgrade a GID file
58 # into a pkcs12 certificate usable in a browser
59 # this bundled format allows for embedding the private key
62 ########## Implementation notes
66 # this implementation is designed as a guideline for
67 # porting to other languages
69 # the decision to go for decorators aims at focusing
70 # on the core of what needs to be done when everything
71 # works fine, and to take caching and error management
74 # for non-pythonic developers, it should be enough to
75 # implement the bulk of this code, namely the _produce methods
76 # and to add caching and error management by whichever means
77 # is available, including inline
79 # (*) self-signed certificates
81 # still with other languages in mind, we've tried to keep the
82 # dependencies to the rest of the code as low as possible
84 # however this still relies on the sfa.trust.certificate module
85 # for the initial generation of a self-signed-certificate that
86 # is associated to the user's ssh-key
87 # (for user-friendliness, and for smooth operations with planetlab,
88 # the usage model is to reuse an existing keypair)
90 # there might be a more portable, i.e. less language-dependant way, to
91 # implement this step by exec'ing the openssl command.
92 # a known successful attempt at this approach that worked
93 # for Java is documented below
94 # http://nam.ece.upatras.gr/fstoolkit/trac/wiki/JavaSFAClient
98 # the implementation of the pkcs12 wrapping, which is a late addition,
99 # is done through direct calls to openssl
103 class SfaClientException (Exception): pass
105 class SfaClientBootstrap:
107 # dir is mandatory but defaults to '.'
108 def __init__ (self, user_hrn, registry_url, dir=None,
109 verbose=False, timeout=None, logger=None):
111 self.registry_url=registry_url
112 if dir is None: dir="."
116 # default for the logger is to use the global sfa logger
118 logger = sfa.util.sfalogging.logger
121 ######################################## *_produce methods
123 # unconditionnally create a self-signed certificate
124 def self_signed_cert_produce (self, output):
125 self.assert_private_key()
126 private_key_filename = self.private_key_filename()
127 keypair=Keypair(filename=private_key_filename)
128 self_signed = Certificate (subject = self.hrn)
129 self_signed.set_pubkey (keypair)
130 self_signed.set_issuer (keypair, self.hrn)
132 self_signed.save_to_file (output)
133 self.logger.debug("SfaClientBootstrap: Created self-signed certificate for %s in %s"%\
138 # unconditionnally retrieve my credential (GetSelfCredential)
139 # we always use the self-signed-cert as the SSL cert
140 def my_credential_produce (self, output):
141 self.assert_self_signed_cert()
142 certificate_filename = self.self_signed_cert_filename()
143 certificate_string = self.plain_read (certificate_filename)
144 self.assert_private_key()
145 registry_proxy = SfaServerProxy (self.registry_url,
146 self.private_key_filename(),
147 certificate_filename)
149 credential_string=registry_proxy.GetSelfCredential (certificate_string, self.hrn, "user")
151 # some urns hrns may replace non hierarchy delimiters '.' with an '_' instead of escaping the '.'
152 hrn = Xrn(self.hrn).get_hrn().replace('\.', '_')
153 credential_string=registry_proxy.GetSelfCredential (certificate_string, hrn, "user")
154 self.plain_write (output, credential_string)
155 self.logger.debug("SfaClientBootstrap: Wrote result of GetSelfCredential in %s"%output)
159 # unconditionnally retrieve my GID - use the general form
160 def my_gid_produce (self,output):
161 return self.gid_produce (output, self.hrn, "user")
163 ### retrieve any credential (GetCredential) unconditionnal form
164 # we always use the GID as the SSL cert
165 def credential_produce (self, output, hrn, type):
167 certificate_filename = self.my_gid_filename()
168 self.assert_private_key()
169 registry_proxy = SfaServerProxy (self.registry_url, self.private_key_filename(),
170 certificate_filename)
171 self.assert_my_credential()
172 my_credential_string = self.my_credential_string()
173 credential_string=registry_proxy.GetCredential (my_credential_string, hrn, type)
174 self.plain_write (output, credential_string)
175 self.logger.debug("SfaClientBootstrap: Wrote result of GetCredential in %s"%output)
178 def slice_credential_produce (self, output, hrn):
179 return self.credential_produce (output, hrn, "slice")
181 def authority_credential_produce (self, output, hrn):
182 return self.credential_produce (output, hrn, "authority")
184 ### retrieve any gid (Resolve) - unconditionnal form
185 # use my GID when available as the SSL cert, otherwise the self-signed
186 def gid_produce (self, output, hrn, type ):
189 certificate_filename = self.my_gid_filename()
191 self.assert_self_signed_cert()
192 certificate_filename = self.self_signed_cert_filename()
194 self.assert_private_key()
195 registry_proxy = SfaServerProxy (self.registry_url, self.private_key_filename(),
196 certificate_filename)
197 credential_string=self.plain_read (self.my_credential())
198 records = registry_proxy.Resolve (hrn, credential_string)
199 records=[record for record in records if record['type']==type]
201 raise RecordNotFound, "hrn %s (%s) unknown to registry %s"%(hrn,type,self.registry_url)
203 self.plain_write (output, record['gid'])
204 self.logger.debug("SfaClientBootstrap: Wrote GID for %s (%s) in %s"% (hrn,type,output))
208 # http://trac.myslice.info/wiki/MySlice/Developer/SFALogin
209 ### produce a pkcs12 bundled certificate from GID and private key
210 # xxx for now we put a hard-wired password that's just, well, 'password'
211 # when leaving this empty on the mac, result can't seem to be loaded in keychain..
212 def my_pkcs12_produce (self, filename):
213 password=raw_input("Enter password for p12 certificate: ")
214 openssl_command=['openssl', 'pkcs12', "-export"]
215 openssl_command += [ "-password", "pass:%s"%password ]
216 openssl_command += [ "-inkey", self.private_key_filename()]
217 openssl_command += [ "-in", self.my_gid_filename()]
218 openssl_command += [ "-out", filename ]
219 if subprocess.call(openssl_command) ==0:
220 print "Successfully created %s"%filename
222 print "Failed to create %s"%filename
224 # Returns True if credential file is valid. Otherwise return false.
225 def validate_credential(self, filename):
227 cred = Credential(filename=filename)
228 # check if credential is expires
229 if cred.get_expiration() < datetime.utcnow():
234 #################### public interface
236 # return my_gid, run all missing steps in the bootstrap sequence
237 def bootstrap_my_gid (self):
238 self.self_signed_cert()
242 # once we've bootstrapped we can use this object to issue any other SFA call
244 def server_proxy (self, url):
246 return SfaServerProxy (url, self.private_key_filename(), self.my_gid_filename(),
247 verbose=self.verbose, timeout=self.timeout)
249 # now in some cases the self-signed is enough
250 def server_proxy_simple (self, url):
251 self.assert_self_signed_cert()
252 return SfaServerProxy (url, self.private_key_filename(), self.self_signed_cert_filename(),
253 verbose=self.verbose, timeout=self.timeout)
255 # this method can optionnally be invoked to ensure proper
256 # installation of the private key that belongs to this user
257 # installs private_key in working dir with expected name -- preserve mode
258 # typically user_private_key would be ~/.ssh/id_rsa
259 # xxx should probably check the 2 files are identical
260 def init_private_key_if_missing (self, user_private_key):
261 private_key_filename=self.private_key_filename()
262 if not os.path.isfile (private_key_filename):
263 key=self.plain_read(user_private_key)
264 self.plain_write(private_key_filename, key)
265 os.chmod(private_key_filename,os.stat(user_private_key).st_mode)
266 self.logger.debug("SfaClientBootstrap: Copied private key from %s into %s"%\
267 (user_private_key,private_key_filename))
269 #################### private details
271 def fullpath (self, file): return os.path.join (self.dir,file)
273 # the expected filenames for the various pieces
274 def private_key_filename (self):
275 return self.fullpath ("%s.pkey" % Xrn.unescape(self.hrn))
276 def self_signed_cert_filename (self):
277 return self.fullpath ("%s.sscert"%self.hrn)
278 def my_credential_filename (self):
279 return self.credential_filename (self.hrn, "user")
280 # the tests use sfi -u <pi-user>; meaning that the slice credential filename
281 # needs to keep track of the user too
282 def credential_filename (self, hrn, type):
284 basename="%s.%s.cred"%(hrn,type)
286 basename="%s-%s.%s.cred"%(self.hrn,hrn,type)
287 return self.fullpath (basename)
288 def slice_credential_filename (self, hrn):
289 return self.credential_filename(hrn,'slice')
290 def authority_credential_filename (self, hrn):
291 return self.credential_filename(hrn,'authority')
292 def my_gid_filename (self):
293 return self.gid_filename (self.hrn, "user")
294 def gid_filename (self, hrn, type):
295 return self.fullpath ("%s.%s.gid"%(hrn,type))
296 def my_pkcs12_filename (self):
297 return self.fullpath ("%s.p12"%self.hrn)
299 # optimizing dependencies
300 # originally we used classes GID or Credential or Certificate
302 # return Credential(filename=self.my_credential()).save_to_string()
303 # but in order to make it simpler to other implementations/languages..
304 def plain_read (self, filename):
305 infile=file(filename,"r")
310 def plain_write (self, filename, contents):
311 outfile=file(filename,"w")
312 result=outfile.write(contents)
315 def assert_filename (self, filename, kind):
316 if not os.path.isfile (filename):
317 raise IOError,"Missing %s file %s"%(kind,filename)
320 def assert_private_key (self):
321 return self.assert_filename (self.private_key_filename(),"private key")
322 def assert_self_signed_cert (self):
323 return self.assert_filename (self.self_signed_cert_filename(),"self-signed certificate")
324 def assert_my_credential (self):
325 return self.assert_filename (self.my_credential_filename(),"user's credential")
326 def assert_my_gid (self):
327 return self.assert_filename (self.my_gid_filename(),"user's GID")
330 # decorator to make up the other methods
331 def get_or_produce (filename_method, produce_method, validate_method=None):
332 # default validator returns true
334 def wrapped (self, *args, **kw):
335 filename=filename_method (self, *args, **kw)
336 if os.path.isfile ( filename ):
337 if not validate_method:
339 elif validate_method(self, filename):
342 # remove invalid file
343 self.logger.warning ("Removing %s - has expired"%filename)
346 produce_method (self, filename, *args, **kw)
351 error = sys.exc_info()[:2]
352 message="Could not produce/retrieve %s (%s -- %s)"%\
353 (filename,error[0],error[1])
354 self.logger.log_exc(message)
355 raise Exception, message
359 @get_or_produce (self_signed_cert_filename, self_signed_cert_produce)
360 def self_signed_cert (self): pass
362 @get_or_produce (my_credential_filename, my_credential_produce, validate_credential)
363 def my_credential (self): pass
365 @get_or_produce (my_gid_filename, my_gid_produce)
366 def my_gid (self): pass
368 @get_or_produce (my_pkcs12_filename, my_pkcs12_produce)
369 def my_pkcs12 (self): pass
371 @get_or_produce (credential_filename, credential_produce, validate_credential)
372 def credential (self, hrn, type): pass
374 @get_or_produce (slice_credential_filename, slice_credential_produce, validate_credential)
375 def slice_credential (self, hrn): pass
377 @get_or_produce (authority_credential_filename, authority_credential_produce, validate_credential)
378 def authority_credential (self, hrn): pass
380 @get_or_produce (gid_filename, gid_produce)
381 def gid (self, hrn, type ): pass
384 # get the credentials as strings, for inserting as API arguments
385 def my_credential_string (self):
387 return self.plain_read(self.my_credential_filename())
388 def slice_credential_string (self, hrn):
389 self.slice_credential(hrn)
390 return self.plain_read(self.slice_credential_filename(hrn))
391 def authority_credential_string (self, hrn):
392 self.authority_credential(hrn)
393 return self.plain_read(self.authority_credential_filename(hrn))
396 def private_key (self):
397 self.assert_private_key()
398 return self.private_key_filename()
400 def delegate_credential_string (self, original_credential, to_hrn, to_type='authority'):
402 sign a delegation credential to someone else
404 original_credential : typically one's user- or slice- credential to be delegated to s/b else
405 to_hrn : the hrn of the person that will be allowed to do stuff on our behalf
406 to_type : goes with to_hrn, usually 'user' or 'authority'
408 returns a string with the delegated credential
410 this internally uses self.my_gid()
411 it also retrieves the gid for to_hrn/to_type
412 and uses Credential.delegate()"""
414 # the gid and hrn of the object we are delegating
415 if isinstance (original_credential, str):
416 original_credential = Credential (string=original_credential)
417 original_gid = original_credential.get_gid_object()
418 original_hrn = original_gid.get_hrn()
420 if not original_credential.get_privileges().get_all_delegate():
421 self.logger.error("delegate_credential_string: original credential %s does not have delegate bit set"%original_hrn)
424 # the delegating user's gid
425 my_gid = self.my_gid()
427 # retrieve the GID for the entity that we're delegating to
428 to_gidfile = self.gid (to_hrn,to_type)
429 # to_gid = GID ( to_gidfile )
430 # to_hrn = delegee_gid.get_hrn()
431 # print 'to_hrn',to_hrn
432 delegated_credential = original_credential.delegate(to_gidfile, self.private_key(), my_gid)
433 return delegated_credential.save_to_string(save_parents=True)