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 check_attribute(self, name, attr): |
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243 | # XXX proof soon |
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244 | if isinstance(name, tuple): |
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245 | raise self.bad_name("ABAC doesn't understand three-names") |
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246 | else: |
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247 | |
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248 | # Naked attributes are attested by this principal |
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249 | if attr.find('.') == -1: a = "%s.%s" % (self.fedid, attr) |
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250 | else: a = attr |
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251 | |
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252 | self.lock.acquire() |
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253 | proof, rv = self.context.query(a, name) |
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254 | # XXX delete soon |
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255 | if not rv and attr in self.globals: rv = True |
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256 | self.lock.release() |
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257 | |
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258 | return rv |
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259 | |
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260 | def set_global_attribute(self, attr): |
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261 | """ |
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262 | Set a global attribute. All names, even those otherwise unknown to the |
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263 | authorizer have this attribute. |
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264 | """ |
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265 | self.lock.acquire() |
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266 | self.globals.add(attr) |
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267 | self.lock.release() |
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268 | |
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269 | def unset_global_attribute(self, attr): |
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270 | """ |
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271 | Remove a global attribute |
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272 | """ |
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273 | |
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274 | self.lock.acquire() |
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275 | self.globals.discard(attr) |
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276 | self.lock.release() |
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277 | |
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278 | def clone(self): |
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279 | self.lock.acquire() |
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280 | rv = abac_authorizer(me=self.me, key=self.key) |
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281 | rv.globals = self.globals.copy() |
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282 | rv.context = ABAC.Context(self.context) |
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283 | self.lock.release() |
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284 | return rv |
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285 | |
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286 | def save(self, dir): |
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287 | self.lock.acquire() |
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288 | try: |
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289 | if not os.access(dir, os.F_OK): |
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290 | os.mkdir(dir) |
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291 | |
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292 | f = open("%s/globals" % dir, "w") |
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293 | pickle.dump(self.globals, f) |
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294 | f.close() |
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295 | |
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296 | if self.me and self.key: |
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297 | f = open("%s/me" % dir, "w") |
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298 | pickle.dump(self.me, f) |
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299 | f.close() |
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300 | f = open("%s/key" % dir, "w") |
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301 | pickle.dump(self.key, f) |
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302 | f.close() |
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303 | if not os.access("%s/certs" %dir, os.F_OK): |
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304 | os.mkdir("%s/certs" % dir) |
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305 | seenit = set() |
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306 | #remove old certs |
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307 | for fn in [ f for f in os.listdir("%s/certs" % dir) \ |
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308 | if re.match('.*\.der$', f)]: |
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309 | os.unlink('%s/certs/%s' % (dir, fn)) |
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310 | ii = 0 |
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311 | ai = 0 |
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312 | for c in self.context.credentials(): |
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313 | id = c.issuer_cert() |
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314 | attr = c.attribute_cert() |
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315 | # NB: file naming conventions matter here. The trailing_ID and |
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316 | # _attr are required by ABAC.COntext.load_directory() |
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317 | if id not in seenit: |
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318 | f = open("%s/certs/ID_%03d_ID.der" % (dir, ii), "w") |
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319 | print >>f, id |
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320 | f.close() |
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321 | ii += 1 |
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322 | seenit.add(id) |
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323 | if attr: |
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324 | f = open("%s/certs/attr_%03d_attr.der" % (dir, ai), "w") |
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325 | print >>f, attr |
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326 | f.close() |
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327 | ai += 1 |
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328 | except EnvironmentError, e: |
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329 | self.lock.release() |
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330 | raise e |
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331 | except pickle.PickleError, e: |
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332 | self.lock.release() |
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333 | raise e |
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334 | self.lock.release() |
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335 | |
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336 | def load(self, dir): |
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337 | self.lock.acquire() |
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338 | try: |
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339 | if os.access("%s/me" % dir, os.R_OK): |
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340 | f = open("%s/me" % dir, "r") |
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341 | self.me = pickle.load(f) |
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342 | f.close() |
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343 | if self.me: |
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344 | self.fedid = fedid(file=self.me) |
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345 | else: |
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346 | self.me = None |
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347 | if os.access("%s/key" % dir, os.R_OK): |
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348 | f = open("%s/key" % dir, "r") |
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349 | self.key = pickle.load(f) |
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350 | f.close() |
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351 | else: |
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352 | self.key = None |
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353 | f = open("%s/globals" % dir, "r") |
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354 | self.globals = pickle.load(f) |
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355 | f.close() |
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356 | self.context = ABAC.Context() |
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357 | self.context.load_directory("%s/certs" % dir) |
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358 | except EnvironmentError, e: |
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359 | self.lock.release() |
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360 | raise e |
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361 | except pickle.PickleError, e: |
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362 | self.lock.release() |
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363 | raise e |
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364 | self.lock.release() |
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365 | |
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366 | def __str__(self): |
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367 | def encode_role(r): |
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368 | if r.is_principal(): |
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369 | return "%s" % r.principal() |
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370 | elif r.is_role(): |
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371 | return "%s.%s" % (r.principal(), r.role_name()) |
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372 | elif r.is_linking(): |
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373 | return "%s.%s.%s" % \ |
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374 | (r.principal(), r.linking_role(), r.role_name()) |
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375 | |
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376 | self.lock.acquire() |
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377 | rv = "%s" % self.fedid |
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378 | for c in self.context.credentials(): |
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379 | rv += '\n%s <- %s' % (encode_role(c.head()), encode_role(c.tail())) |
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380 | self.lock.release() |
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381 | return rv |
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382 | |
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