source: fedd/federation/desktop_access.py @ 2dc99e3

Last change on this file since 2dc99e3 was 2dc99e3, checked in by Ted Faber <faber@…>, 11 years ago

More tweaks. This version will connect to DETER
  • Property mode set to 100644
File size: 19.7 KB
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1#!/usr/local/bin/python
2
3import os,sys
4import re
5import string
6import copy
7import pickle
8import logging
9import random
10import subprocess
11
12from util import *
13from deter import fedid, generate_fedid
14from authorizer import authorizer, abac_authorizer
15from service_error import service_error
16from remote_service import xmlrpc_handler, soap_handler, service_caller
17
18from deter import topdl
19
20from access import access_base
21
22# Make log messages disappear if noone configures a fedd logger.  This is
23# something of an incantation, but basically it creates a logger object
24# registered to fedd.access if no other module above us has.  It's an extra
25# belt for the suspenders.
26class nullHandler(logging.Handler):
27    def emit(self, record): pass
28
29fl = logging.getLogger("fedd.access")
30fl.addHandler(nullHandler())
31
32
33# The plug-in itself.
34class access(access_base):
35    """
36    This is a demonstration plug-in for fedd.  It responds to all the
37    experiment_control requests and keeps internal state.  The allocations it
38    makes are simple integers associated with each valid request.  It makes use
39    of the general routines in access.access_base.
40
41    Detailed comments in the code and info at
42    """
43    def __init__(self, config=None, auth=None):
44        """
45        Initializer.  Pulls parameters out of the ConfigParser's access
46        section, and initializes simple internal state.  This version reads a
47        maximum integer to assign from the configuration file, while most other
48        configuration entries  are read by the base class. 
49
50        An access database in the cannonical format is also read as well as a
51        state database that is a hash of internal state.  Routines to
52        manipulate these are in the base class, but specializations appear
53        here.
54
55        The access database maps users to a simple string.
56        """
57
58        # Calling the base initializer, which reads canonical configuration
59        # information and initializes canonical members.
60        access_base.__init__(self, config, auth)
61        # Reading the maximum integer parameter from the configuration file
62
63        self.src_addr = config.get('access', 'interface_address')
64        self.router = config.get('access', 'gateway')
65        self.hostname = config.get('access', 'hostname')
66        # Storage for ephemeral ssh keys and host files
67        self.localdir = config.get('access', 'localdir')
68        self.ssh_identity = None
69
70        # hostname is the name of the ssh endpoint for the other side.  That
71        # side needs it to set up routing tables.  If hostname is not
72        # available, but an IP address is, use that.
73        if self.hostname is None:
74            if  self.src_addr is None:
75                raise service_error(service_error.server_config,
76                        'Hostname or interface_address must be set in config')
77            self.hostname = self.src_addr
78       
79        self.ssh_port = config.get('access', 'ssh_port', '22')
80
81        # authorization information
82        self.auth_type = config.get('access', 'auth_type') \
83                or 'abac'
84        self.auth_dir = config.get('access', 'auth_dir')
85        accessdb = config.get("access", "accessdb")
86        # initialize the authorization system.  We make a call to
87        # read the access database that maps from authorization information
88        # into local information.  The local information is parsed by the
89        # translator above.
90        if self.auth_type == 'abac':
91            #  Load the current authorization state
92            self.auth = abac_authorizer(load=self.auth_dir)
93            self.access = [ ]
94            if accessdb:
95                try:
96                    self.read_access(accessdb)
97                except EnvironmentError, e:
98                    self.log.error("Cannot read %s: %s" % \
99                            (config.get("access", "accessdb"), e))
100                    raise e
101        else:
102            raise service_error(service_error.internal, 
103                    "Unknown auth_type: %s" % self.auth_type)
104
105        # The superclass has read the state, but if this is the first run ever,
106        # we must initialise the running flag.  This plugin only supports one
107        # connection, so StartSegment will fail when self.state['running'] is
108        # true.
109        self.state_lock.acquire()
110        if 'running' not in self.state:
111            self.state['running'] = False
112        self.state_lock.release()
113
114        # These dictionaries register the plug-in's local routines for handline
115        # these four messages with the server code above.  There's a version
116        # for SOAP and XMLRPC, depending on which interfaces the plugin
117        # supports.  There's rarely a technical reason not to support one or
118        # the other - the plugin code almost never deals with the transport -
119        # but if a plug-in writer wanted to disable XMLRPC, they could leave
120        # the self.xmlrpc_services dictionary empty.
121        self.soap_services = {\
122            'RequestAccess': soap_handler("RequestAccess", self.RequestAccess),
123            'ReleaseAccess': soap_handler("ReleaseAccess", self.ReleaseAccess),
124            'StartSegment': soap_handler("StartSegment", self.StartSegment),
125            'TerminateSegment': soap_handler("TerminateSegment", 
126                self.TerminateSegment),
127            }
128        self.xmlrpc_services =  {\
129            'RequestAccess': xmlrpc_handler('RequestAccess',
130                self.RequestAccess),
131            'ReleaseAccess': xmlrpc_handler('ReleaseAccess',
132                self.ReleaseAccess),
133            'StartSegment': xmlrpc_handler("StartSegment", self.StartSegment),
134            'TerminateSegment': xmlrpc_handler('TerminateSegment',
135                self.TerminateSegment),
136            }
137        self.call_SetValue = service_caller('SetValue', log=self.log)
138        self.call_GetValue = service_caller('GetValue', log=self.log)
139
140    # ReleaseAccess come from the base class, this is a slightly modified
141    # RequestAccess from the base that includes a fedAttr to force this side to
142    # be active.
143    def RequestAccess(self, req, fid):
144        """
145        Handle an access request.  Success here maps the requester into the
146        local access control space and establishes state about that user keyed
147        to a fedid.  We also save a copy of the certificate underlying that
148        fedid so this allocation can access configuration information and
149        shared parameters on the experiment controller.
150        """
151
152        self.log.info("RequestAccess called by %s" % fid)
153        # The dance to get into the request body
154        if req.has_key('RequestAccessRequestBody'):
155            req = req['RequestAccessRequestBody']
156        else:
157            raise service_error(service_error.req, "No request!?")
158
159        # Base class lookup routine.  If this fails, it throws a service
160        # exception denying access that triggers a fault response back to the
161        # caller.
162        found,  owners, proof = self.lookup_access(req, fid)
163        self.log.info(
164                "[RequestAccess] Access granted local creds %s" % found)
165        # Make a fedid for this allocation
166        allocID, alloc_cert = generate_fedid(subj="alloc", log=self.log)
167        aid = unicode(allocID)
168
169        # Store the data about this allocation:
170        self.state_lock.acquire()
171        self.state[aid] = { }
172        self.state[aid]['user'] = found
173        self.state[aid]['owners'] = owners
174        self.state[aid]['auth'] = set()
175        # Authorize the creating fedid and the principal representing the
176        # allocation to manipulate it.
177        self.append_allocation_authorization(aid, 
178                ((fid, allocID), (allocID, allocID)))
179        self.write_state()
180        self.state_lock.release()
181
182        # Create a directory to stash the certificate in, ans stash it.
183        try:
184            f = open("%s/%s.pem" % (self.certdir, aid), "w")
185            print >>f, alloc_cert
186            f.close()
187        except EnvironmentError, e:
188            raise service_error(service_error.internal, 
189                    "Can't open %s/%s : %s" % (self.certdir, aid, e))
190        self.log.debug('[RequestAccess] Returning allocation ID: %s' % allocID)
191        msg = { 
192                'allocID': { 'fedid': allocID }, 
193                'fedAttr': [{ 'attribute': 'nat_portals', 'value': 'True' }],
194                'proof': proof.to_dict()
195                }
196        return msg
197
198    def validate_topology(self, top):
199        '''
200        Validate the topology.  Desktops can only be single connections.
201        Though the topology will include a portal and a node, the access
202        controller will implement both on one node.
203
204        As more capabilities are added to the contoller the constraints here
205        will relax.
206        '''
207
208        comps = []
209        for e in top.elements:
210            if isinstance(e, topdl.Computer): comps.append(e)
211        if len(comps) > 2: 
212            raise service_error(service_error.req,
213                    "Desktop only supports 1-node subexperiments")
214
215        portals = 0
216        for c in comps:
217            if c.get_attribute('portal') is not None: 
218                portals += 1
219                continue
220            if len(c.interface) > 1:
221                raise service_error(service_error.req,
222                        "Desktop Node has more than one interface")
223            i  = c.interface[0]
224            if len(i.subs) > 1: 
225                raise service_error(service_error.req,
226                        "Desktop Node has more than one substate on interface")
227            sub = i.subs[0]
228            for i in sub.interfaces:
229                if i.element not in comps:
230                    raise service_error(service_error.req,
231                            "Desktop Node connected to non-portal")
232
233        if portals > 1:
234            raise service_error(service_error.req,
235                    "Desktop segment has more than one portal")
236        return True
237
238    def validate_connInfo(self, connInfo):
239        if len(connInfo) != 1: 
240            raise service_error(service_error.req,
241                    "Desktop segment requests multiple connections")
242        if connInfo[0]['type'] != 'ssh':
243            raise service_error(service_error.req,
244                    "Desktop segment requires ssh connecton")
245        return True
246
247    def export_store_info(self, certfile, connInfo):
248        '''
249        Tell the other portal node where to reach this desktop.  The other side
250        uses this information to set up routing, though the ssh_port is unused
251        as the Desktop always initiates ssh connections.
252        '''
253        values = { 'peer': self.hostname, 'ssh_port': self.ssh_port }
254        for c in connInfo:
255            for p in c.get('parameter', []):
256                if p.get('type','') == 'input': continue
257                pname = p.get('name', '')
258                key = p.get('key', '')
259                surl = p.get('store', '')
260                if pname not in values:
261                    self.log('Unknown export parameter: %s'  % pname)
262                    continue
263                val = values[pname]
264                req = { 'name': key, 'value': val }
265                self.log.debug('Setting %s (%s) to %s on %s' % \
266                        (pname, key,  val, surl))
267                self.call_SetValue(surl, req, certfile)
268
269    def set_route(self, dest, script, gw=None, src=None):
270        if sys.platform.startswith('freebsd'):
271            if src is not None and gw is not None:
272                raise service_error(service_error.internal, 
273                        'FreeBSD will not route based on src address')
274            elif src is not None:
275                raise service_error(service_error.internal, 
276                        'FreeBSD will not route based on src address')
277            elif gw is not None:
278                print >>script, 'sudo route add %s %s' % (dest, gw)
279        elif sys.platform.startswith('linux'):
280            if src is not None and gw is not None:
281                print >>script, 'sudo ip route add %s via %s src %s' % \
282                        (dest, gw, src)
283            elif src is not None:
284                print >>script, 'sudo ip route add %s src %s' % \
285                        (dest, src)
286            elif gw is not None:
287                print >>script, 'sudo ip route add %s via %s' % (dest, gw)
288        else:
289            raise service_error(service_error.internal, 
290                    'Unknown platform %s' % sys.platform)
291
292    def unset_route(self, dest, script):
293        rv = 0
294        if sys.platform.startswith('freebsd'):
295            print >>script, 'sudo route delete %s' % dest
296        elif sys.platform.startswith('linux'):
297            print >>script, 'sudo ip route delete %s' % dest
298
299    def find_a_peer(self, addr): 
300        '''
301        Find another node in the experiment that's on our subnet.  This is a
302        hack to handle the problem that we really cannot require the desktop to
303        dynamically route.  Will be improved by distributing static routes.
304        '''
305
306        peer = None
307        hosts = os.path.join(self.localdir, 'hosts')
308        p = addr.rfind('.')
309        if p == -1:
310            raise service_error(service_error.req, 'bad address in topology')
311        prefix = addr[0:p]
312        addr_re = re.compile('(%s.\\d+)' % prefix)
313        try:
314            f = open(hosts, 'r')
315            for line in f:
316                m = addr_re.search(line)
317                if m is not None and m.group(1) != addr:
318                    peer = m.group(1)
319                    break
320            else:
321                raise service_error(service_error.req, 
322                        'No other nodes in this subnet??')
323        except EnvironmentError, e:
324            raise service_error(service_error.internal, 
325                    'Cannot open %s: %s' % (e.filename, e.strerror))
326        return peer
327
328
329
330
331    def configure_desktop(self, top, connInfo):
332        '''
333        Build the connection.  Establish routing to the peer if using a
334        separate interface, wait until the other end confirms setup, establish
335        the ssh layer-two tunnel (tap), assign the in-experiment IP address to
336        the tunnel and establish routing to the experiment through the tap.
337        '''
338
339
340        # get the peer and ssh port from the portal and our IP from the other
341        peer = None
342        port = None
343        my_addr = None
344        for e in top.elements:
345            if not isinstance(e, topdl.Computer): continue
346            if e.get_attribute('portal') is None: 
347                # there should be one interface with one IPv4 address
348                if len(e.interface) <1 :
349                    raise service_error(service_error.internal,
350                            'No interface on experiment node!?!?')
351                my_addr = e.interface[0].get_attribute('ip4_address')
352            else:
353                for ci in connInfo:
354                    if ci.get('portal', '') != e.name: continue
355                    peer = ci.get('peer')
356                    port = '22'
357                    for a in ci.get('fedAttr', []):
358                        if a['attribute'] == 'ssh_port': port = a['value']
359
360        # XXX scan hosts for IP addresses and compose better routing entry
361       
362        if not all([peer, port, my_addr]):
363            raise service_error(service_error.req, 
364                    'Cannot find all config parameters %s %s %s' % (peer, port, my_addr))
365
366        exp_peer = self.find_a_peer(my_addr)
367
368        cscript = os.path.join(self.localdir, 'connect')
369        dscript = os.path.join(self.localdir, 'disconnect')
370        try:
371            f = open(cscript, 'w')
372            print >>f, '#!/bin/sh'
373            # This picks the outgoing interface to the experiment using the
374            # routing system.
375            self.set_route(peer, f, self.router, self.src_addr)
376            # Wait until the other end reports that it is configured py placing
377            # a file this end can access into its local file system.  Try once
378            # a minute.
379            print >>f,'while ! /usr/bin/scp -o "StrictHostKeyChecking no" -i %s %s:/usr/local/federation/etc/prep_done /dev/null; do' % (self.ssh_identity, peer)
380            print >>f, 'sleep 60; done'
381            print >>f, ('sudo ssh -w 0:0 -p %s -o "Tunnel ethernet" ' + \
382                    '-o "StrictHostKeyChecking no" -i %s %s perl -I/usr/local/federation/lib /usr/local/federation/bin/setup_bridge.pl --tapno=0 --addr=%s &') % \
383                    (port, self.ssh_identity, peer, my_addr)
384            # This should give the tap a a chance to come up
385            print >>f,'sleep 10'
386            # Assign its address and route connections through it.
387            print >>f, 'sudo ifconfig tap0 %s netmask 255.255.255.0 up' % \
388                    my_addr
389            self.set_route('10.0.0.0/8', f, exp_peer)
390            f.close()
391            os.chmod(cscript, 0755)
392            f = open(dscript, 'w')
393            print >>f, '#!/bin/sh'
394            print >>f, 'sudo ifconfig tap0 destroy'
395            self.unset_route(peer, f)
396            self.unset_route('10.0.0.0/8', f)
397            f.close()
398            os.chmod(dscript, 0755)
399        except EnvironmentError, e:
400            raise service_error(service_error.internal, 
401                    'Cannot create connect %s: %s' % (e.filename, e.strerror))
402        #subprocess.call(['/bin/sh', cscript])
403        return True
404
405    def StartSegment(self, req, fid):
406        """
407        Start a segment.  In this simple skeleton, this means to parse the
408        request and assign an unassigned integer to it.  We store the integer
409        in the persistent state.
410        """
411        try:
412            req = req['StartSegmentRequestBody']
413            # Get the request topology.  If not present, a KeyError is thrown.
414            topref = req['segmentdescription']['topdldescription']
415            # The fedid of the allocation we're attaching resources to
416            auth_attr = req['allocID']['fedid']
417        except KeyError:
418            raise service_error(service_error.req, "Badly formed request")
419
420        # String version of the allocation ID for keying
421        aid = "%s" % auth_attr
422        # Authorization check
423        access_ok, proof = self.auth.check_attribute(fid, auth_attr, 
424                with_proof=True)
425        if not access_ok:
426            raise service_error(service_error.access, "Access denied", 
427                    proof=proof)
428        else:
429            # See if this is a replay of an earlier succeeded StartSegment -
430            # sometimes SSL kills 'em.  If so, replay the response rather than
431            # redoing the allocation.
432            self.state_lock.acquire()
433            # Test and set :-)
434            running = self.state['running']
435            self.state['running'] = True
436            retval = self.state[aid].get('started', None)
437            self.state_lock.release()
438            if retval:
439                self.log.warning(
440                        "[StartSegment] Duplicate StartSegment for %s: " \
441                                % aid + \
442                        "replaying response")
443                return retval
444            if running:
445                self.log.debug('[StartSegment] already running')
446                raise service_error(service_error.federant,
447                        'Desktop is already in an experiment')
448
449        certfile = "%s/%s.pem" % (self.certdir, aid)
450
451        # Convert the topology into topdl data structures.  Again, the
452        # skeletion doesn't do anything with it, but this is how one parses a
453        # topology request.
454        if topref: topo = topdl.Topology(**topref)
455        else:
456            raise service_error(service_error.req, 
457                    "Request missing segmentdescription'")
458
459        err = None
460        try:
461            self.validate_topology(topo)
462
463            # The attributes of the request.  The ones we care about are the ssh
464            # keys to operate the tunnel.
465            attrs = req.get('fedAttr', [])
466            for a in attrs:
467                # Save the hosts and ssh_privkeys to our local dir
468                if a['attribute'] in ('hosts', 'ssh_secretkey'):
469                    self.log.debug('Getting %s from %s' % \
470                            (a['attribute'], a['value']))
471                    get_url(a['value'], certfile, self.localdir, log=self.log)
472                    base = os.path.basename(a['value'])
473                    if a['attribute'] == 'ssh_secretkey':
474                        self.ssh_identity = os.path.join(self.localdir, base)
475                    os.chmod(os.path.join(self.localdir, base), 0600)
476                else:
477                    self.log.debug('Ignoring attribute %s' % a['attribute'])
478
479            # Gather connection information and exchange parameters.
480            connInfo = req.get('connection', [])
481            self.validate_connInfo(connInfo)
482            self.export_store_info(certfile, connInfo)
483            self.import_store_info(certfile, connInfo)
484
485            #build it
486            self.configure_desktop(topo, connInfo)
487        except service_error, e:
488            err = e
489
490        # Save the information
491        if err is None:
492            # It's possible that the StartSegment call gets retried (!).  if
493            # the 'started' key is in the allocation, we'll return it rather
494            # than redo the setup.  The integer allocation was saved when we
495            # made it.
496            self.state_lock.acquire()
497            self.state[aid]['started'] = { 
498                    'allocID': req['allocID'],
499                    'allocationLog': "Allocatation complete",
500                    'segmentdescription': { 'topdldescription': topo.to_dict() },
501                    'proof': proof.to_dict(),
502                    }
503            retval = copy.deepcopy(self.state[aid]['started'])
504            self.write_state()
505            self.state_lock.release()
506        else:
507            # Something bad happened - clear the "running" flag so we can try
508            # again
509            self.state_lock.acquire()
510            self.state['running'] = False
511            self.state_lock.release()
512            raise err
513
514        return retval
515
516    def TerminateSegment(self, req, fid):
517        """
518        Remove the resources associated with th eallocation and stop the music.
519        In this example, this simply means removing the integer we allocated.
520        """
521        # Gather the same access information as for Start Segment
522        try:
523            req = req['TerminateSegmentRequestBody']
524        except KeyError:
525            raise service_error(service_error.req, "Badly formed request")
526
527        auth_attr = req['allocID']['fedid']
528        aid = "%s" % auth_attr
529
530        self.log.debug("Terminate request for %s" %aid)
531        # Check authorization
532        access_ok, proof = self.auth.check_attribute(fid, auth_attr, 
533                with_proof=True)
534        if not access_ok:
535            raise service_error(service_error.access, "Access denied", 
536                    proof=proof)
537        cscript = os.path.join(self.localdir, 'connect')
538        dscript = os.path.join(self.localdir, 'disconnect')
539        # XXX restore this
540        #if os.path.exists(dscript):
541            #self.log.debug('calling %s' % dscript)
542            #rv = subprocess.call(['/bin/sh', dscript])
543            #if rv != 0:
544                #self.log.warning('%s had an error: %d' % (dscript, rv))
545        #else:
546            #self.log.warn('No disconnection script!?')
547
548        try:
549            for bfn in os.listdir(self.localdir):
550                fn = os.path.join(self.localdir, bfn)
551                self.log.debug('Removing %s' % fn)
552                if os.path.exists(fn):
553                    os.remove(fn)
554        except EnvironmentError, e:
555            self.log.warn('Failed to remove %s: %s' % (e.filename, e.strerror))
556
557        self.ssh_identity = None
558
559        self.state_lock.acquire()
560        self.state['running'] = False
561        self.state_lock.release()
562   
563        return { 'allocID': req['allocID'], 'proof': proof.to_dict() }
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