1 | package net.deterlab.abac; |
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2 | |
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3 | import java.util.*; |
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4 | |
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5 | import org.bouncycastle.asn1.*; |
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6 | |
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7 | /** |
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8 | * Represents a role, which is a vertex in a Credential graph. |
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9 | */ |
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10 | public class Role implements Comparable { |
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11 | protected String m_string; |
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12 | protected String[] m_parts; |
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13 | protected String m_A_r1; |
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14 | protected String m_r2; |
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15 | protected String m_prefix; |
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16 | protected Role[] m_prereqs; |
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17 | |
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18 | /** |
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19 | * Create a role from a string. A single role must be of the format "A", |
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20 | * "A.r1", or "A.r1.r2", where A is a principal and r1 and r2 are role |
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21 | * names. This constructor also supports intersection roles: a sequence of |
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22 | * two or more roles separated by "&". The whitespace surrounding & |
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23 | * is arbitrary. |
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24 | * |
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25 | * If the string does not have this format, the constructor throws a |
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26 | * RuntimeException. |
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27 | */ |
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28 | public Role(String s) throws RuntimeException { |
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29 | m_string = s; |
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30 | |
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31 | // intersection roles have at least two roles separated by "&" |
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32 | String[] isect_roles = s.split("&"); |
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33 | |
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34 | // ordinary role |
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35 | if (isect_roles.length == 1) |
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36 | single_role(); |
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37 | |
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38 | // intersection role: make a list of prereqs |
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39 | else { |
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40 | m_prereqs = new Role[isect_roles.length]; |
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41 | |
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42 | // trim() handles arbitrary whitespace |
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43 | for (int i = 0; i < isect_roles.length; ++i) |
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44 | m_prereqs[i] = new Role(isect_roles[i].trim()); |
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45 | |
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46 | // this make is_principal etc. work properly |
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47 | m_parts = new String[0]; |
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48 | } |
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49 | } |
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50 | |
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51 | public Role(String s, Context c) { |
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52 | this(c.expandKeyID(s)); |
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53 | } |
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54 | |
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55 | public Role(Role r) { |
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56 | m_string = r.m_string; |
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57 | m_A_r1 = r.m_A_r1; |
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58 | m_r2 = r.m_r2; |
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59 | m_prefix = r.m_prefix; |
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60 | m_parts = new String[r.m_parts.length]; |
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61 | for (int i = 0; i < r.m_parts.length; i++) |
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62 | m_parts[i] = r.m_parts[i]; |
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63 | m_prereqs = new Role[m_prereqs.length]; |
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64 | for (int i = 0; i < r.m_prereqs.length; i++) |
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65 | m_prereqs[i] = new Role(r.m_prereqs[i]); |
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66 | } |
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67 | |
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68 | /** |
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69 | * Initialize a single non-intersection role. See constructor for details of |
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70 | * role format. Will throw RuntimeException if the role is invalid. |
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71 | */ |
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72 | private void single_role() throws RuntimeException { |
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73 | m_parts = m_string.split("\\."); |
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74 | if (m_parts.length > 3) |
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75 | throw new RuntimeException("Not a valid role: " + m_string); |
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76 | |
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77 | // linking role: prefix is A.r1 from A.r1.r2 |
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78 | if (is_linking()) { |
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79 | m_A_r1 = m_parts[0] + "." + m_parts[1]; |
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80 | m_r2 = m_parts[2]; |
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81 | m_prefix = m_A_r1; |
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82 | } |
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83 | |
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84 | // role: prefix is A from A.r1 |
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85 | else if (is_role()) |
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86 | m_prefix = m_parts[0]; |
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87 | |
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88 | // principal: prefix is the whole thing |
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89 | else |
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90 | m_prefix = m_string; |
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91 | } |
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92 | |
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93 | /** |
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94 | * Returns true iff the role is a principal. |
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95 | */ |
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96 | public boolean is_principal() { return m_parts.length == 1; } |
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97 | |
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98 | /** |
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99 | * Returns true iff the role is a role (i.e., A.r1). |
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100 | */ |
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101 | public boolean is_role() { return m_parts.length == 2; } |
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102 | |
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103 | /** |
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104 | * Returns true iff the role is a linking role (i.e., A.r1.r2). |
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105 | */ |
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106 | public boolean is_linking() { return m_parts.length == 3; } |
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107 | |
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108 | /** |
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109 | * Returns true iff the role represents an intersection role. |
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110 | */ |
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111 | public boolean is_intersection() { return m_prereqs != null; } |
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112 | |
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113 | /** |
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114 | * Returns the first two elements of a linking role's name. This typically |
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115 | * refers to another role in the graph. This will throw a runtime |
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116 | * exception if the node is not a linking role. |
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117 | */ |
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118 | String A_r1() throws RuntimeException { |
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119 | if (!is_linking()) |
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120 | throw new RuntimeException("Not a linking role"); |
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121 | return m_A_r1; |
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122 | } |
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123 | |
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124 | /** |
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125 | * Return the last element of a linking role's name. This will throw a |
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126 | * runtime exception if the node is not a linking role. |
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127 | */ |
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128 | String r2() throws RuntimeException { |
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129 | if (!is_linking()) |
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130 | throw new RuntimeException("Not a linking role"); |
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131 | return m_r2; |
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132 | } |
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133 | |
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134 | /** |
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135 | * Returns the principal part of a role or principal. This is everything |
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136 | * except the last element of the name. |
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137 | */ |
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138 | public String principal_part() { |
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139 | return m_prefix; |
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140 | } |
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141 | |
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142 | public String principal() { return m_parts.length > 0 ? m_parts[0] : null; } |
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143 | public String role_name() { return m_parts.length > 1 ? m_parts[1] : null; } |
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144 | public String linked_role() { return A_r1(); } |
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145 | |
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146 | /** |
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147 | * Get the roles that form the prerequisites to this intersection. Throws |
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148 | * a runtime exception if this is not an intersection role. |
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149 | */ |
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150 | Role[] prereqs() throws RuntimeException { |
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151 | if (!is_intersection()) |
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152 | throw new RuntimeException("Not an intersection role."); |
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153 | |
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154 | return m_prereqs; |
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155 | } |
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156 | |
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157 | public String toString() { |
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158 | return m_string; |
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159 | } |
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160 | |
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161 | public String simpleString(Context c) { |
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162 | return c.expandNickname(m_string); |
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163 | } |
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164 | |
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165 | public boolean equals(Object v2) { |
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166 | if (v2 instanceof Role) |
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167 | return m_string.equals(((Role)v2).m_string); |
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168 | return false; |
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169 | } |
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170 | |
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171 | public int compareTo(Object o) { |
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172 | if (o instanceof Role) |
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173 | return m_string.compareTo(((Role)o).m_string); |
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174 | else return 1; |
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175 | } |
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176 | |
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177 | public int hashCode() { |
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178 | return m_string.hashCode(); |
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179 | } |
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180 | |
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181 | } |
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