source: fedd/federation/legacy_access.py @ 0c9393e

#!/usr/local/bin/python

import os,sys
import stat # for chmod constants
import re
import random
import string
import copy
import pickle
import logging
import subprocess

from threading import *
from M2Crypto.SSL import SSLError

from util import *
from allocate_project import allocate_project_local, allocate_project_remote
from fedid import fedid, generate_fedid
from authorizer import authorizer
from service_error import service_error
from remote_service import xmlrpc_handler, soap_handler, service_caller

import httplib
import tempfile
from urlparse import urlparse

import topdl
import list_log
import proxy_emulab_segment
import local_emulab_segment


# Make log messages disappear if noone configures a fedd logger
class nullHandler(logging.Handler):
    def emit(self, record): pass

fl = logging.getLogger("fedd.access")
fl.addHandler(nullHandler())

class legacy_access:
    """
    This collects the legacy access control helpers in one place.
    """

    class parse_error(RuntimeError): pass

    def __init__(self): pass

    def legacy_read_access(self, config, access_obj=None):
        """
        Read an access DB with filename config  of the form:
            (id, id, id) -> attribute, something
        where the ids can be fedids, strings, or <any> or <none>, attribute is
        the attribute to assign , and something is any set of charcters.  The
        hash self.access is populated with mappings from those triples to the
        results of access_obj being called on the remainder of the line (if
        present).  If access_obj is not given, the string itself is entered in
        the hash.  Additionally, a triple with <any> and <none> mapped to None
        is entered in self.auth with the attribute given.

        Parsing errors result in a self.parse_error exception being raised.
        access_obj should throw that as well.
        """
        lineno=0
        name_expr = "["+string.ascii_letters + string.digits + "\.\-_]+"
        fedid_expr = "fedid:[" + string.hexdigits + "]+"
        key_name = "(<ANY>|<NONE>|"+fedid_expr + "|"+ name_expr + ")"
        access_re = re.compile('\('+key_name+'\s*,\s*'+key_name+'\s*,\s*'+
                key_name+'\s*\)\s*->\s*([^,]+)\s*(.*)', re.IGNORECASE)

        def parse_name(n):
            if n.startswith('fedid:'): return fedid(hexstr=n[len('fedid:'):])
            else: return n
        
        def auth_name(n):
            if isinstance(n, basestring):
                if n =='<any>' or n =='<none>': return None
                else: return unicode(n)
            else:
                return n
        def strip_comma(s):
            s = s.strip()
            if s.startswith(','):
                s = s[1:].strip()
            return s

        if access_obj is None:
            access_obj = lambda(x): "%s" % x

        f = open(config, "r");
        try:
            for line in f:
                lineno += 1
                line = line.strip();
                if len(line) == 0 or line.startswith('#'):
                    continue

                # Access line (t, p, u) -> anything
                m = access_re.match(line)
                if m != None:
                    access_key = tuple([ parse_name(x) \
                            for x in m.group(1,2,3)])
                    attribute = m.group(4)
                    auth_key = tuple([ auth_name(x) for x in access_key])
                    self.auth.set_attribute(auth_key, attribute)
                    if len(m.group(5)) > 0:
                        access_val = access_obj(strip_comma(m.group(5)))
                        self.access[access_key] = access_val
                    continue

                # Nothing matched to here: unknown line - raise exception
                f.close()
                raise self.parse_error(
                        "Unknown statement at line %d of %s" % \
                        (lineno, config))
        finally:
            if f: f.close()

    @staticmethod
    def permute_wildcards(a, p):
        """Return a copy of a with various fields wildcarded.

        The bits of p control the wildcards.  A set bit is a wildcard
        replacement with the lowest bit being user then project then testbed.
        """
        if p & 1: user = ["<any>"]
        else: user = a[2]
        if p & 2: proj = "<any>"
        else: proj = a[1]
        if p & 4: tb = "<any>"
        else: tb = a[0]

        return (tb, proj, user)

    def legacy_find_access(self, search):
        """
        Search the access DB for a match on this tuple.  Return the matching
        access tuple and the user that matched.
        
        NB, if the initial tuple fails to match we start inserting wildcards in
        an order determined by self.project_priority.  Try the list of users in
        order (when wildcarded, there's only one user in the list).
        """
        if self.project_priority: perm = (0, 1, 2, 3, 4, 5, 6, 7)
        else: perm = (0, 2, 1, 3, 4, 6, 5, 7)

        for p in perm: 
            s = self.permute_wildcards(search, p)
            # s[2] is None on an anonymous, unwildcarded request
            if s[2] != None:
                for u in s[2]:
                    if self.access.has_key((s[0], s[1], u)):
                        return (self.access[(s[0], s[1], u)], u)
            else:
                if self.access.has_key(s):
                    return (self.access[s], None)
        return None, None

    def legacy_lookup_access_base(self, req, fid):
        """
        Determine the allowed access for this request.  Return the access and
        which fields are dynamic.

        The fedid is needed to construct the request
        """
        user_re = re.compile("user:\s(.*)")
        project_re = re.compile("project:\s(.*)")

        # Search keys
        tb = fid
        user = [ user_re.findall(x)[0] for x in req.get('credential', []) \
                if user_re.match(x)]
        project = [ project_re.findall(x)[0] \
                for x in req.get('credential', []) \
                    if project_re.match(x)]

        if len(project) == 1: project = project[0]
        elif len(project) == 0: project = None
        else: 
            raise service_error(service_error.req, 
                    "More than one project credential")

        # Confirm authorization
        for u in user:
            self.log.debug("[lookup_access] Checking access for %s" % \
                    ((tb, project, u),))
            if self.auth.check_attribute((tb, project, u), 'access'):
                self.log.debug("[lookup_access] Access granted")
                break
            else:
                self.log.debug("[lookup_access] Access Denied")
        else:
            raise service_error(service_error.access, "Access denied")

        # This maps a valid user to the Emulab projects and users to use
        found, user_match = self.legacy_find_access((tb, project, user))

        return (found, (tb, project, user_match))