| 1 | #/usr/local/bin/python |
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| 2 | |
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| 3 | from string import join |
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| 4 | from tempfile import mkstemp |
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| 5 | from subprocess import call |
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| 6 | from threading import Lock |
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| 7 | |
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| 8 | from fedid import fedid |
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| 9 | from remote_service import service_caller |
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| 10 | from abac_remote_service import abac_service_caller |
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| 11 | from service_error import service_error |
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| 12 | |
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| 13 | |
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| 14 | import ABAC |
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| 15 | import pickle |
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| 16 | |
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| 17 | import sys |
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| 18 | import os |
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| 19 | import re |
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| 20 | |
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| 21 | class authorizer_base: |
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| 22 | """ |
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| 23 | Classes based on this one keep track of authorization attributes for the |
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| 24 | various modules running. This base class holds some utility functions that |
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| 25 | they all potentially use. |
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| 26 | """ |
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| 27 | |
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| 28 | # general error exception for badly formed names. |
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| 29 | class bad_name(RuntimeError): pass |
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| 30 | # difficulty creating an attribute |
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| 31 | class attribute_error(RuntimeError): pass |
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| 32 | |
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| 33 | @staticmethod |
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| 34 | def auth_name(name): |
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| 35 | """ |
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| 36 | Helper to convert a non-unicode local name to a unicode string. Mixed |
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| 37 | representations can needlessly confuse the authorizer. |
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| 38 | """ |
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| 39 | if isinstance(name, basestring): |
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| 40 | if not isinstance(name, unicode): return unicode(name) |
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| 41 | else: return name |
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| 42 | else: return name |
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| 43 | |
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| 44 | @staticmethod |
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| 45 | def valid_name(name): |
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| 46 | """ |
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| 47 | Ensure that the given name is valid. A valid name can either be a |
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| 48 | triple of strings and fedids representing one of our generalized Emulab |
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| 49 | names or a single fedid. Compound names can include wildcards (None) |
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| 50 | and must anchor to a fedid at their highest level (unless they're all |
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| 51 | None) |
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| 52 | |
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| 53 | This either returns True or throws an exception. More an assertion |
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| 54 | than a function. |
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| 55 | """ |
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| 56 | if isinstance(name, tuple) and len(name) == 3: |
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| 57 | for n in name: |
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| 58 | if n: |
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| 59 | if not (isinstance(n, basestring) or isinstance(n, fedid)): |
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| 60 | raise authorizer_base.bad_name( |
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| 61 | "names must be either a triple or a fedid") |
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| 62 | for n in name: |
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| 63 | if n: |
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| 64 | if isinstance(n, fedid): |
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| 65 | return True |
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| 66 | else: |
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| 67 | raise authorizer_base.bad_name( |
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| 68 | "Compound names must be " + \ |
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| 69 | "rooted in fedids: %s" % str(name)) |
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| 70 | |
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| 71 | return True |
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| 72 | elif isinstance(name, fedid): |
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| 73 | return True |
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| 74 | else: |
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| 75 | raise authorizer_base.bad_name( |
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| 76 | "Names must be a triple or a fedid (%s)" % name) |
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| 77 | |
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| 78 | |
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| 79 | class authorizer(authorizer_base): |
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| 80 | """ |
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| 81 | This class keeps track of authorization attributes for the various modules |
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| 82 | running. When it gets smarter it will be the basis for a real |
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| 83 | attribute-based authentication system. |
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| 84 | """ |
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| 85 | def __init__(self, def_attr="testbed"): |
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| 86 | self.attrs = { } |
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| 87 | self.globals=set() |
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| 88 | |
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| 89 | def set_attribute(self, name, attr): |
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| 90 | """ |
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| 91 | Attach attr to name. Multiple attrs can be attached. |
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| 92 | """ |
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| 93 | self.valid_name(name) |
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| 94 | if isinstance(name, tuple): |
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| 95 | aname = tuple([ self.auth_name(n) for n in name]) |
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| 96 | else: |
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| 97 | aname = self.auth_name(name) |
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| 98 | |
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| 99 | if not self.attrs.has_key(aname): |
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| 100 | self.attrs[aname] = set() |
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| 101 | self.attrs[aname].add(attr) |
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| 102 | |
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| 103 | def unset_attribute(self, name, attr): |
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| 104 | """ |
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| 105 | Remove an attribute from name |
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| 106 | """ |
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| 107 | self.valid_name(name) |
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| 108 | if isinstance(name, tuple): |
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| 109 | aname = tuple([ self.auth_name(n) for n in name]) |
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| 110 | else: |
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| 111 | aname = self.auth_name(name) |
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| 112 | |
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| 113 | attrs = self.attrs.get(aname, None) |
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| 114 | if attrs: attrs.discard(attr) |
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| 115 | |
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| 116 | def check_attribute(self, name, attr): |
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| 117 | """ |
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| 118 | Return True if name has attr (or if attr is global). Tuple names match |
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| 119 | any tuple name that matches all names present and has None entries in |
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| 120 | other fileds. For tuple names True implies that there is a matching |
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| 121 | tuple name with the attribute. |
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| 122 | """ |
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| 123 | def tup(tup, i, p): |
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| 124 | mask = 1 << i |
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| 125 | if p & mask : return authorizer.auth_name(tup[i]) |
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| 126 | else: return None |
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| 127 | |
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| 128 | self.valid_name(name) |
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| 129 | if attr in self.globals: |
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| 130 | return True |
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| 131 | |
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| 132 | if isinstance(name, tuple): |
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| 133 | for p in range(0,8): |
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| 134 | lookup = ( tup(name, 0, p), tup(name,1, p), tup(name,2,p)) |
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| 135 | if self.attrs.has_key(lookup): |
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| 136 | if attr in self.attrs[lookup]: |
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| 137 | return True |
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| 138 | else: |
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| 139 | return attr in self.attrs.get(self.auth_name(name), set()) |
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| 140 | |
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| 141 | def set_global_attribute(self, attr): |
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| 142 | """ |
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| 143 | Set a global attribute. All names, even those otherwise unknown to the |
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| 144 | authorizer have this attribute. |
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| 145 | """ |
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| 146 | self.globals.add(attr) |
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| 147 | |
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| 148 | def unset_global_attribute(self, attr): |
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| 149 | """ |
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| 150 | Remove a global attribute |
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| 151 | """ |
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| 152 | |
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| 153 | self.globals.discard(attr) |
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| 154 | |
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| 155 | def __str__(self): |
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| 156 | rv = "" |
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| 157 | rv += "attrs %s\n" % self.attrs |
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| 158 | rv += "globals %s" % self.globals |
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| 159 | return rv |
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| 160 | |
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| 161 | def clone(self): |
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| 162 | rv = authorizer() |
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| 163 | rv.attrs = self.attrs.copy() |
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| 164 | rv.globals = self.globals.copy() |
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| 165 | return rv |
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| 166 | |
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| 167 | def save(self, fn): |
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| 168 | f = open(fn, "w") |
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| 169 | pickle.dump(self, f) |
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| 170 | f.close() |
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| 171 | |
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| 172 | def load(self, fn): |
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| 173 | f = open(fn, "r") |
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| 174 | a = pickle.load(f) |
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| 175 | f.close() |
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| 176 | self.attrs = a.attrs |
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| 177 | self.globals = a.globals |
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| 178 | |
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| 179 | |
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| 180 | class abac_authorizer(authorizer_base): |
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| 181 | """ |
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| 182 | Use the ABAC authorization system to make attribute decisions. |
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| 183 | """ |
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| 184 | |
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| 185 | def __init__(self, certs=None, me=None, key=None): |
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| 186 | self.bad_name = authorizer_base.bad_name |
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| 187 | self.attribute_error = authorizer_base.attribute_error |
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| 188 | self.globals = set() |
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| 189 | self.creddy = '/usr/local/bin/creddy' |
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| 190 | self.me = me |
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| 191 | self.key = key |
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| 192 | self.context = ABAC.Context() |
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| 193 | self.lock = Lock() |
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| 194 | |
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| 195 | if me: |
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| 196 | self.fedid = fedid(file=self.me) |
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| 197 | self.context.load_id_file(self.me) |
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| 198 | |
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| 199 | for dir in certs or []: |
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| 200 | self.context.load_directory(dir) |
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| 201 | |
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| 202 | def set_attribute(self, name=None, attr=None, cert=None): |
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| 203 | if name and attr: |
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| 204 | if isinstance(name, tuple): |
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| 205 | raise self.bad_name("ABAC doesn't understand three-names") |
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| 206 | if self.me and self.key: |
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| 207 | # Create a credential and insert it into context |
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| 208 | # This will simplify when we have libcreddy |
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| 209 | try: |
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| 210 | # create temp file |
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| 211 | f, fn = mkstemp() |
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| 212 | os.close(f) |
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| 213 | except EnvironmentError, e: |
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| 214 | raise self.attribute_error( |
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| 215 | "Cannot create temp file: %s" %e) |
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| 216 | |
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| 217 | # Create the attribute certificate with creddy |
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| 218 | cmd = [self.creddy, '--attribute', '--issuer=%s' % self.me, |
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| 219 | '--key=%s' % self.key, '--role=%s' % attr, |
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| 220 | '--subject-id=%s' % name, '--out=%s' % fn] |
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| 221 | rv = call(cmd) |
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| 222 | if rv == 0: |
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| 223 | self.lock.acquire() |
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| 224 | # load it to context and remove the file |
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| 225 | rv = self.context.load_attribute_file(fn) |
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| 226 | self.lock.release() |
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| 227 | os.unlink(fn) |
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| 228 | else: |
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| 229 | os.unlink(fn) |
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| 230 | raise self.attribute_error("creddy returned %s" % rv) |
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| 231 | else: |
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| 232 | raise self.attribute_error( |
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| 233 | "Identity and key not specified on creation") |
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| 234 | elif cert: |
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| 235 | # Insert this credential into the context |
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| 236 | self.lock.acquire() |
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| 237 | self.context.load_attribute_chunk(cert) |
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| 238 | self.lock.release() |
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| 239 | else: |
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| 240 | raise self.attribute_error("Neither name/attr nor cert is set") |
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| 241 | |
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| 242 | def unset_attribute(self, name, attr): |
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| 243 | if isinstance(name, tuple): |
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| 244 | raise self.bad_name("ABAC doesn't understand three-names") |
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| 245 | self.lock.acquire() |
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| 246 | ctxt = ABAC.Context() |
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| 247 | ids = set() |
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| 248 | for c in self.context.credentials(): |
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| 249 | h = c.head() |
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| 250 | t = c.tail() |
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| 251 | if h.is_role() and t.is_principal(): |
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| 252 | if t.principal() == '%s' % name and \ |
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| 253 | h.principal() == '%s' % self.fedid and \ |
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| 254 | h.role_name() == attr: |
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| 255 | continue |
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| 256 | |
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| 257 | id = c.issuer_cert() |
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| 258 | if id not in ids: |
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| 259 | ctxt.load_id_chunk(id) |
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| 260 | ids.add(id) |
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| 261 | ctxt.load_attribute_chunk(c.attribute_cert()) |
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| 262 | self.context = ctxt |
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| 263 | self.lock.release() |
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| 264 | |
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| 265 | |
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| 266 | def check_attribute(self, name, attr): |
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| 267 | # XXX proof soon |
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| 268 | if isinstance(name, tuple): |
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| 269 | raise self.bad_name("ABAC doesn't understand three-names") |
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| 270 | else: |
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| 271 | |
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| 272 | # Naked attributes are attested by this principal |
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| 273 | if attr.find('.') == -1: a = "%s.%s" % (self.fedid, attr) |
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| 274 | else: a = attr |
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| 275 | |
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| 276 | self.lock.acquire() |
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| 277 | proof, rv = self.context.query(a, name) |
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| 278 | # XXX delete soon |
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| 279 | if not rv and attr in self.globals: rv = True |
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| 280 | self.lock.release() |
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| 281 | |
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| 282 | return rv |
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| 283 | |
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| 284 | def set_global_attribute(self, attr): |
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| 285 | """ |
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| 286 | Set a global attribute. All names, even those otherwise unknown to the |
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| 287 | authorizer have this attribute. |
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| 288 | """ |
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| 289 | self.lock.acquire() |
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| 290 | self.globals.add(attr) |
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| 291 | self.lock.release() |
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| 292 | |
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| 293 | def unset_global_attribute(self, attr): |
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| 294 | """ |
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| 295 | Remove a global attribute |
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| 296 | """ |
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| 297 | |
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| 298 | self.lock.acquire() |
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| 299 | self.globals.discard(attr) |
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| 300 | self.lock.release() |
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| 301 | |
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| 302 | def clone(self): |
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| 303 | self.lock.acquire() |
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| 304 | rv = abac_authorizer(me=self.me, key=self.key) |
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| 305 | rv.globals = self.globals.copy() |
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| 306 | rv.context = ABAC.Context(self.context) |
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| 307 | self.lock.release() |
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| 308 | return rv |
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| 309 | |
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| 310 | def save(self, dir): |
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| 311 | self.lock.acquire() |
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| 312 | try: |
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| 313 | if not os.access(dir, os.F_OK): |
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| 314 | os.mkdir(dir) |
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| 315 | |
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| 316 | f = open("%s/globals" % dir, "w") |
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| 317 | pickle.dump(self.globals, f) |
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| 318 | f.close() |
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| 319 | |
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| 320 | if self.me and self.key: |
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| 321 | f = open("%s/me" % dir, "w") |
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| 322 | pickle.dump(self.me, f) |
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| 323 | f.close() |
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| 324 | f = open("%s/key" % dir, "w") |
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| 325 | pickle.dump(self.key, f) |
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| 326 | f.close() |
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| 327 | if not os.access("%s/certs" %dir, os.F_OK): |
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| 328 | os.mkdir("%s/certs" % dir) |
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| 329 | seenit = set() |
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| 330 | #remove old certs |
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| 331 | for fn in [ f for f in os.listdir("%s/certs" % dir) \ |
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| 332 | if re.match('.*\.der$', f)]: |
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| 333 | os.unlink('%s/certs/%s' % (dir, fn)) |
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| 334 | ii = 0 |
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| 335 | ai = 0 |
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| 336 | for c in self.context.credentials(): |
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| 337 | id = c.issuer_cert() |
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| 338 | attr = c.attribute_cert() |
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| 339 | # NB: file naming conventions matter here. The trailing_ID and |
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| 340 | # _attr are required by ABAC.COntext.load_directory() |
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| 341 | if id not in seenit: |
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| 342 | f = open("%s/certs/ID_%03d_ID.der" % (dir, ii), "w") |
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| 343 | print >>f, id |
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| 344 | f.close() |
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| 345 | ii += 1 |
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| 346 | seenit.add(id) |
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| 347 | if attr: |
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| 348 | f = open("%s/certs/attr_%03d_attr.der" % (dir, ai), "w") |
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| 349 | print >>f, attr |
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| 350 | f.close() |
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| 351 | ai += 1 |
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| 352 | except EnvironmentError, e: |
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| 353 | self.lock.release() |
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| 354 | raise e |
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| 355 | except pickle.PickleError, e: |
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| 356 | self.lock.release() |
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| 357 | raise e |
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| 358 | self.lock.release() |
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| 359 | |
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| 360 | def load(self, dir): |
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| 361 | self.lock.acquire() |
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| 362 | try: |
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| 363 | if os.access("%s/me" % dir, os.R_OK): |
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| 364 | f = open("%s/me" % dir, "r") |
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| 365 | self.me = pickle.load(f) |
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| 366 | f.close() |
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| 367 | if self.me: |
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| 368 | self.fedid = fedid(file=self.me) |
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| 369 | else: |
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| 370 | self.me = None |
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| 371 | if os.access("%s/key" % dir, os.R_OK): |
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| 372 | f = open("%s/key" % dir, "r") |
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| 373 | self.key = pickle.load(f) |
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| 374 | f.close() |
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| 375 | else: |
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| 376 | self.key = None |
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| 377 | f = open("%s/globals" % dir, "r") |
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| 378 | self.globals = pickle.load(f) |
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| 379 | f.close() |
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| 380 | self.context = ABAC.Context() |
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| 381 | self.context.load_directory("%s/certs" % dir) |
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| 382 | except EnvironmentError, e: |
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| 383 | self.lock.release() |
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| 384 | raise e |
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| 385 | except pickle.PickleError, e: |
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| 386 | self.lock.release() |
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| 387 | raise e |
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| 388 | self.lock.release() |
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| 389 | |
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| 390 | def __str__(self): |
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| 391 | def encode_role(r): |
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| 392 | if r.is_principal(): |
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| 393 | return "%s" % r.principal() |
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| 394 | elif r.is_role(): |
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| 395 | return "%s.%s" % (r.principal(), r.role_name()) |
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| 396 | elif r.is_linking(): |
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| 397 | return "%s.%s.%s" % \ |
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| 398 | (r.principal(), r.linking_role(), r.role_name()) |
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| 399 | |
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| 400 | self.lock.acquire() |
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| 401 | rv = "%s" % self.fedid |
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| 402 | for c in self.context.credentials(): |
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| 403 | rv += '\n%s <- %s' % (encode_role(c.head()), encode_role(c.tail())) |
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| 404 | self.lock.release() |
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| 405 | return rv |
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| 406 | |
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