1 | package net.deterlab.abac; |
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2 | |
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3 | import org.apache.commons.collections15.*; |
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4 | |
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5 | import edu.uci.ics.jung.graph.*; |
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6 | import edu.uci.ics.jung.graph.util.*; |
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7 | |
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8 | import java.util.*; |
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9 | |
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10 | /** |
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11 | * A class for making queries against the graph. It supports direct queries as |
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12 | * well as reachability in either direction. See the run method for details. |
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13 | */ |
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14 | public class Query { |
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15 | private Graph<Role,Credential> g; |
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16 | private int vertex_count; |
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17 | |
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18 | public Query(Graph<Role,Credential> g) { |
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19 | this.g = g; |
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20 | } |
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21 | |
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22 | /** |
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23 | * Run a query against the graph, returning a graph of the results. If the |
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24 | * results are empty or the query fails, an empty graph is returned. When |
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25 | * derived edges are involved, the subgraphs that imply those edges are |
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26 | * included. |
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27 | */ |
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28 | public Graph<Role,Credential> run(String attr, String prin) { |
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29 | Role attribute = new Role(attr); |
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30 | Role principal = new Role(prin); |
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31 | Graph<Role,Credential> ret = |
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32 | Graphs.<Role,Credential>synchronizedDirectedGraph( |
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33 | new DirectedSparseGraph<Role,Credential>()); |
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34 | |
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35 | /* empty attribute, non-empty principal: find everywhere the principal can go */ |
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36 | if (attr.isEmpty() && !prin.isEmpty()) { |
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37 | if (g.containsVertex(principal)) { |
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38 | CollectReversePath collect = new CollectReversePath(ret); |
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39 | forward_dfs(principal, collect); |
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40 | } |
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41 | } |
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42 | |
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43 | /* otherwise we're going to do some kind of a reverse dfs */ |
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44 | else if (g.containsVertex(attribute)) { |
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45 | if ( prin == null || prin.isEmpty()) { |
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46 | CollectQueryGraph collect = new CollectQueryGraph(ret); |
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47 | reverse_dfs(new Role(attr), collect); |
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48 | } |
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49 | else { |
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50 | if ( g.containsVertex(principal)) { |
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51 | CollectQueryPath collect = new CollectQueryPath(ret, principal); |
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52 | reverse_dfs(new Role(attr), collect); |
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53 | } |
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54 | } |
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55 | } |
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56 | |
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57 | vertex_count = ret.getVertexCount(); |
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58 | |
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59 | return ret; |
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60 | } |
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61 | |
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62 | /** |
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63 | * Returns true after running a query that returns a non-empty set of |
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64 | * vertices. |
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65 | */ |
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66 | public boolean successful() { |
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67 | return vertex_count > 0; |
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68 | } |
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69 | |
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70 | /** |
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71 | * Returns a collection of principals reachable from a Role when |
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72 | * traversing edges in the reverse direction. |
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73 | */ |
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74 | public Set<Role> find_principals(Role n) { |
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75 | Set<Role> principals = new HashSet<Role>(); |
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76 | |
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77 | GetPrincipals f = new GetPrincipals(principals); |
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78 | reverse_dfs(n, f); |
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79 | return principals; |
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80 | } |
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81 | |
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82 | |
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83 | /** |
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84 | * Interface to pass to the reverse_dfs class. The node function gets |
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85 | * called for every node visited by the dfs. |
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86 | */ |
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87 | interface DfsFcn { |
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88 | public void node(Role x); |
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89 | public void node_after(Role x); |
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90 | } |
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91 | |
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92 | /** |
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93 | * Class used to pull all the principals out of a reverse_dfs searched |
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94 | * graph. It takes a collection to the constructor and adds all principals |
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95 | * it sees to that collection. In no collection is passed in, it creates a |
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96 | * local HashSet of vertices. The collection is accessible via the p |
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97 | * (i.e., principals) member. |
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98 | */ |
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99 | private class GetPrincipals implements DfsFcn { |
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100 | public Collection<Role> p; |
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101 | |
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102 | public GetPrincipals(Collection<Role> vc) { |
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103 | if ( vc != null) { p =vc;} |
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104 | else { p = new HashSet<Role>(); } |
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105 | } |
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106 | |
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107 | public void node(Role r) { |
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108 | if ( r.is_principal() ) p.add(r); |
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109 | } |
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110 | public void node_after(Role r) { } |
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111 | } |
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112 | |
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113 | /** |
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114 | * Collect a subgraph. Add every node and outgoing arc we encounter, and |
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115 | * pull in the linking node subtrees as well. Because it's possible that |
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116 | * linking node subtrees have been encountered more than once, we're |
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117 | * careful not to pull them in twice. The created graph is found in the |
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118 | * public ng member. |
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119 | */ |
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120 | private class CollectQueryGraph implements DfsFcn { |
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121 | public Graph<Role, Credential> ng; |
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122 | protected HashSet<Role> linking_roles_seen; |
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123 | |
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124 | public CollectQueryGraph(Graph<Role,Credential> g) { |
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125 | ng = g; |
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126 | linking_roles_seen = new HashSet<Role>(); |
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127 | } |
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128 | |
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129 | public void node(Role r) { |
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130 | if (r.is_linking() && !linking_roles_seen.contains(r)) { |
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131 | // Collect this linking role subgraph |
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132 | reverse_dfs(new Role(r.principal_part()), this); |
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133 | linking_roles_seen.add(r); |
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134 | } |
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135 | // Add this node's children |
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136 | for (Credential c : g.getInEdges(r) ) { |
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137 | Role tail = g.getSource(c); |
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138 | ng.addEdge(c, tail, r); // FIXME tail and r can come from c [?] |
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139 | } |
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140 | } |
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141 | public void node_after(Role r) { } |
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142 | |
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143 | } |
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144 | |
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145 | /** |
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146 | * Collect the path from one node to another. It only includes vertices that |
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147 | * are traversed to reach the node. It also includes subgraphs that imply |
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148 | * the linking edges traversed. |
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149 | */ |
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150 | private class CollectQueryPath extends CollectQueryGraph { |
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151 | HashSet<Role> onPath; // Vertices on the path to the principal |
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152 | public CollectQueryPath(Graph<Role,Credential> g, Role dest) { |
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153 | super(g); |
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154 | onPath = new HashSet<Role>(); |
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155 | onPath.add(dest); |
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156 | } |
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157 | |
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158 | public void node(Role r) { } |
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159 | |
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160 | public void node_after(Role r) { |
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161 | for (Credential c : g.getInEdges(r)) { |
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162 | Role child = c.tail(); |
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163 | |
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164 | if (onPath.contains(child)) { |
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165 | Credential edge = g.findEdge(child, r); |
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166 | if (edge == null) |
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167 | throw new RuntimeException("Credential missing from parent graph, state is messed up"); |
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168 | |
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169 | ng.addEdge(edge, child, r); |
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170 | onPath.add(r); |
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171 | |
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172 | // For linking roles, collect the whole subgraph of the |
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173 | // authorizer |
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174 | if (r.is_linking()) { |
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175 | CollectQueryPath link = new CollectQueryPath(ng, new Role(child.principal_part())); |
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176 | reverse_dfs(new Role(r.principal_part()), link); |
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177 | } |
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178 | } |
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179 | } |
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180 | } |
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181 | } |
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182 | |
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183 | /** |
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184 | * Collect the path that a node can reach. It includes subgraphs that imply |
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185 | * the linked edges traversed. |
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186 | */ |
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187 | private class CollectReversePath extends CollectQueryGraph { |
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188 | public CollectReversePath(Graph<Role,Credential> g) { |
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189 | super(g); |
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190 | } |
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191 | |
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192 | /* add all of the node's parents */ |
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193 | public void node(Role r) { |
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194 | for (Credential c : g.getOutEdges(r)) { |
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195 | Role head = g.getDest(c); |
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196 | Credential cred = g.findEdge(r, head); |
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197 | if (cred == null) |
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198 | throw new RuntimeException("Credential missing from parent graph, state is messed up"); |
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199 | |
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200 | ng.addEdge(cred, r, head); |
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201 | } |
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202 | } |
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203 | |
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204 | public void node_after(Role r) { |
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205 | for (Credential c : g.getOutEdges(r)) { |
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206 | Role parent = g.getDest(c); |
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207 | |
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208 | // if any of the links we follow is derived, copy the subgraph |
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209 | // that implies said link |
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210 | if (parent.is_linking()) { |
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211 | CollectQueryPath link = new CollectQueryPath(ng, new Role(r.principal_part())); |
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212 | reverse_dfs(new Role(parent.principal_part()), link); |
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213 | } |
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214 | } |
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215 | } |
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216 | } |
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217 | |
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218 | /** |
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219 | * Interface to the reverse_dfs member that does allocates the visited map |
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220 | * so the user doesn't have to. |
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221 | * */ |
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222 | private void reverse_dfs(Role r, DfsFcn f) { |
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223 | reverse_dfs(r, new HashSet<Role>(), f); |
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224 | } |
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225 | |
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226 | /** |
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227 | * Member function to walk the edges in reverse from a given Role. Each |
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228 | * Role is visited once and has the node() function of the dfs_fcn called |
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229 | * on it. Order is not guaranteed. |
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230 | */ |
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231 | private void reverse_dfs(Role r, HashSet<Role> visited, |
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232 | DfsFcn f) { |
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233 | if (visited.contains(r)) return; |
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234 | |
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235 | f.node(r); |
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236 | visited.add(r); |
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237 | |
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238 | for (Credential c : g.getInEdges(r)) |
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239 | reverse_dfs(g.getSource(c), visited, f); |
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240 | f.node_after(r); |
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241 | } |
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242 | |
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243 | /** |
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244 | * Interface to the forward_dfs member that allocates the visited map so |
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245 | * the user doesn't have to. |
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246 | */ |
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247 | private void forward_dfs(Role r, DfsFcn f) { |
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248 | forward_dfs(r, new HashSet<Role>(), f); |
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249 | } |
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250 | |
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251 | /** |
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252 | * Member function to walk the edges from a given Role. Each Role is |
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253 | * visited once and has the node() function of the dfs_fcn called on it. |
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254 | * Order is not guaranteed |
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255 | */ |
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256 | private void forward_dfs(Role r, Set<Role> visited, DfsFcn f) { |
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257 | if (visited.contains(r)) return; |
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258 | |
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259 | f.node(r); |
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260 | visited.add(r); |
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261 | |
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262 | for (Credential c : g.getOutEdges(r)) |
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263 | forward_dfs(g.getDest(c), visited, f); |
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264 | f.node_after(r); |
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265 | } |
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266 | } |
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