2 # This module implements a hierarchy of authorities and performs a similar
3 # function as the "tree" module of the original SFA prototype. An HRN
4 # is assumed to be a string of authorities separated by dots. For example,
5 # "planetlab.us.arizona.bakers". Each component of the HRN is a different
6 # authority, with the last component being a leaf in the tree.
8 # Each authority is stored in a subdirectory on the registry. Inside this
9 # subdirectory are several files:
11 # *.PKEY - private key file
12 # *.DBINFO - database info
20 from sfa.util.report import *
21 from sfa.trust.certificate import Keypair
22 from sfa.trust.credential import *
23 from sfa.trust.gid import GID, create_uuid
24 from sfa.util.namespace import *
25 from sfa.util.config import Config
26 from sfa.util.sfaticket import SfaTicket
29 # The AuthInfo class contains the information for an authority. This information
30 # includes the GID, private key, and database connection information.
36 privkey_filename = None
37 dbinfo_filename = None
40 # Initialize and authority object.
42 # @param xrn the human readable name of the authority (urn will be converted to hrn)
43 # @param gid_filename the filename containing the GID
44 # @param privkey_filename the filename containing the private key
45 # @param dbinfo_filename the filename containing the database info
47 def __init__(self, xrn, gid_filename, privkey_filename, dbinfo_filename):
48 hrn, type = urn_to_hrn(xrn)
50 self.set_gid_filename(gid_filename)
51 self.privkey_filename = privkey_filename
52 self.dbinfo_filename = dbinfo_filename
55 # Set the filename of the GID
57 # @param fn filename of file containing GID
59 def set_gid_filename(self, fn):
60 self.gid_filename = fn
61 self.gid_object = None
64 # Get the GID in the form of a GID object
66 def get_gid_object(self):
67 if not self.gid_object:
68 self.gid_object = GID(filename = self.gid_filename)
69 return self.gid_object
72 # Get the private key in the form of a Keypair object
74 def get_pkey_object(self):
75 return Keypair(filename = self.privkey_filename)
78 # Get the dbinfo in the form of a dictionary
81 f = file(self.dbinfo_filename)
87 # Replace the GID with a new one. The file specified by gid_filename is
88 # overwritten with the new GID object
90 # @param gid object containing new GID
92 def update_gid_object(self, gid):
93 gid.save_to_file(self.gid_filename)
97 # The Hierarchy class is responsible for managing the tree of authorities.
98 # Each authority is a node in the tree and exists as an AuthInfo object.
100 # The tree is stored on disk in a hierarchical manner than reflects the
101 # structure of the tree. Each authority is a subdirectory, and each subdirectory
102 # contains the GID, pkey, and dbinfo files for that authority (as well as
103 # subdirectories for each sub-authority)
107 # Create the hierarchy object.
109 # @param basedir the base directory to store the hierarchy in
111 def __init__(self, basedir = None):
113 self.config = Config()
114 basedir = os.path.join(self.config.SFA_DATA_DIR, "authorities")
115 self.basedir = basedir
117 # Given a hrn, return the filenames of the GID, private key, and dbinfo
120 # @param xrn the human readable name of the authority (urn will be convertd to hrn)
122 def get_auth_filenames(self, xrn):
123 hrn, type = urn_to_hrn(xrn)
125 parent_hrn = get_authority(hrn)
126 directory = os.path.join(self.basedir, hrn.replace(".", "/"))
128 gid_filename = os.path.join(directory, leaf+".gid")
129 privkey_filename = os.path.join(directory, leaf+".pkey")
130 dbinfo_filename = os.path.join(directory, leaf+".dbinfo")
132 return (directory, gid_filename, privkey_filename, dbinfo_filename)
135 # Check to see if an authority exists. An authority exists if it's disk
138 # @param the human readable name of the authority to check
140 def auth_exists(self, xrn):
141 hrn, type = urn_to_hrn(xrn)
142 (directory, gid_filename, privkey_filename, dbinfo_filename) = \
143 self.get_auth_filenames(hrn)
145 return os.path.exists(gid_filename) and \
146 os.path.exists(privkey_filename) and \
147 os.path.exists(dbinfo_filename)
150 # Create an authority. A private key for the authority and the associated
151 # GID are created and signed by the parent authority.
153 # @param xrn the human readable name of the authority to create (urn will be converted to hrn)
154 # @param create_parents if true, also create the parents if they do not exist
156 def create_auth(self, xrn, create_parents=False):
157 hrn, type = urn_to_hrn(xrn)
158 trace("Hierarchy: creating authority: " + hrn)
160 # create the parent authority if necessary
161 parent_hrn = get_authority(hrn)
162 if (parent_hrn) and (not self.auth_exists(parent_hrn)) and (create_parents):
163 self.create_auth(parent_hrn, create_parents)
165 (directory, gid_filename, privkey_filename, dbinfo_filename) = \
166 self.get_auth_filenames(hrn)
168 # create the directory to hold the files
170 os.makedirs(directory)
171 # if the path already exists then pass
172 except OSError, (errno, strerr):
176 if os.path.exists(privkey_filename):
177 print "using existing key", privkey_filename, "for authority", hrn
178 pkey = Keypair(filename = privkey_filename)
180 pkey = Keypair(create = True)
181 pkey.save_to_file(privkey_filename)
183 gid = self.create_gid(xrn, create_uuid(), pkey)
184 gid.save_to_file(gid_filename, save_parents=True)
186 # XXX TODO: think up a better way for the dbinfo to work
188 dbinfo = Config().get_plc_dbinfo()
189 dbinfo_file = file(dbinfo_filename, "w")
190 dbinfo_file.write(str(dbinfo))
194 # Return the AuthInfo object for the specified authority. If the authority
195 # does not exist, then an exception is thrown. As a side effect, disk files
196 # and a subdirectory may be created to store the authority.
198 # @param xrn the human readable name of the authority to create (urn will be converted to hrn).
200 def get_auth_info(self, xrn):
202 #trace("Hierarchy: getting authority: " + hrn)
203 hrn, type = urn_to_hrn(xrn)
204 if not self.auth_exists(hrn):
205 raise MissingAuthority(hrn)
207 (directory, gid_filename, privkey_filename, dbinfo_filename) = \
208 self.get_auth_filenames(hrn)
210 auth_info = AuthInfo(hrn, gid_filename, privkey_filename, dbinfo_filename)
212 # check the GID and see if it needs to be refreshed
213 gid = auth_info.get_gid_object()
214 gid_refreshed = self.refresh_gid(gid)
215 if gid != gid_refreshed:
216 auth_info.update_gid_object(gid_refreshed)
221 # Create a new GID. The GID will be signed by the authority that is it's
222 # immediate parent in the hierarchy (and recursively, the parents' GID
223 # will be signed by its parent)
225 # @param hrn the human readable name to store in the GID
226 # @param uuid the unique identifier to store in the GID
227 # @param pkey the public key to store in the GID
229 def create_gid(self, xrn, uuid, pkey):
230 hrn, type = urn_to_hrn(xrn)
231 # Using hrn_to_urn() here to make sure the urn is in the right format
232 # If xrn was a hrn instead of a urn, then the gid's urn will be
234 urn = hrn_to_urn(hrn, type)
235 gid = GID(subject=hrn, uuid=uuid, hrn=hrn, urn=urn)
237 parent_hrn = get_authority(hrn)
238 if not parent_hrn or hrn == self.config.SFA_INTERFACE_HRN:
239 # if there is no parent hrn, then it must be self-signed. this
240 # is where we terminate the recursion
241 gid.set_issuer(pkey, hrn)
243 # we need the parent's private key in order to sign this GID
244 parent_auth_info = self.get_auth_info(parent_hrn)
245 gid.set_issuer(parent_auth_info.get_pkey_object(), parent_auth_info.hrn)
246 gid.set_parent(parent_auth_info.get_gid_object())
255 # Refresh a GID. The primary use of this function is to refresh the
256 # the expiration time of the GID. It may also be used to change the HRN,
257 # UUID, or Public key of the GID.
259 # @param gid the GID to refresh
260 # @param hrn if !=None, change the hrn
261 # @param uuid if !=None, change the uuid
262 # @param pubkey if !=None, change the public key
264 def refresh_gid(self, gid, xrn=None, uuid=None, pubkey=None):
265 # TODO: compute expiration time of GID, refresh it if necessary
266 gid_is_expired = False
268 # update the gid if we need to
269 if gid_is_expired or xrn or uuid or pubkey:
274 uuid = gid.get_uuid()
276 pubkey = gid.get_pubkey()
278 gid = self.create_gid(xrn, uuid, pubkey)
283 # Retrieve an authority credential for an authority. The authority
284 # credential will contain the authority privilege and will be signed by
285 # the authority's parent.
287 # @param hrn the human readable name of the authority (urn is converted to hrn)
288 # @param authority type of credential to return (authority | sa | ma)
290 def get_auth_cred(self, xrn, kind="authority"):
291 hrn, type = urn_to_hrn(xrn)
292 auth_info = self.get_auth_info(hrn)
293 gid = auth_info.get_gid_object()
295 cred = Credential(subject=hrn)
296 cred.set_gid_caller(gid)
297 cred.set_gid_object(gid)
298 cred.set_privileges(kind)
299 cred.set_delegate(True)
300 cred.set_pubkey(auth_info.get_gid_object().get_pubkey())
302 parent_hrn = get_authority(hrn)
303 if not parent_hrn or hrn == self.config.SFA_INTERFACE_HRN:
304 # if there is no parent hrn, then it must be self-signed. this
305 # is where we terminate the recursion
306 cred.set_issuer(auth_info.get_pkey_object(), hrn)
308 # we need the parent's private key in order to sign this GID
309 parent_auth_info = self.get_auth_info(parent_hrn)
310 cred.set_issuer(parent_auth_info.get_pkey_object(), parent_auth_info.hrn)
311 cred.set_parent(self.get_auth_cred(parent_hrn, kind))
318 # Retrieve an authority ticket. An authority ticket is not actually a
319 # redeemable ticket, but only serves the purpose of being included as the
320 # parent of another ticket, in order to provide a chain of authentication
323 # This looks almost the same as get_auth_cred, but works for tickets
324 # XXX does similarity imply there should be more code re-use?
326 # @param xrn the human readable name of the authority (urn is converted to hrn)
328 def get_auth_ticket(self, xrn):
329 hrn, type = urn_to_hrn(xrn)
330 auth_info = self.get_auth_info(hrn)
331 gid = auth_info.get_gid_object()
333 ticket = SfaTicket(subject=hrn)
334 ticket.set_gid_caller(gid)
335 ticket.set_gid_object(gid)
336 ticket.set_delegate(True)
337 ticket.set_pubkey(auth_info.get_gid_object().get_pubkey())
339 parent_hrn = get_authority(hrn)
341 # if there is no parent hrn, then it must be self-signed. this
342 # is where we terminate the recursion
343 ticket.set_issuer(auth_info.get_pkey_object(), hrn)
345 # we need the parent's private key in order to sign this GID
346 parent_auth_info = self.get_auth_info(parent_hrn)
347 ticket.set_issuer(parent_auth_info.get_pkey_object(), parent_auth_info.hrn)
348 ticket.set_parent(self.get_auth_cred(parent_hrn))