1 | #include <assert.h> |
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2 | #include <stdlib.h> |
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3 | |
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4 | #include "abac_graph.h" |
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5 | |
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6 | #include "abac_set.h" |
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7 | #include "abac_util.h" |
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8 | |
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9 | #include "uthash.h" |
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10 | |
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11 | // vertex |
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12 | struct _abac_vertex_t { |
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13 | abac_role_t *role; |
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14 | char *name; |
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15 | |
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16 | abac_list_t *edges; |
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17 | |
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18 | // only relevant to intersection edges |
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19 | abac_list_t *prereqs; |
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20 | |
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21 | UT_hash_handle hh; |
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22 | }; |
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23 | |
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24 | // edge |
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25 | typedef struct _abac_edge_t { |
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26 | abac_vertex_t *vertex; |
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27 | abac_credential_t *credential; |
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28 | } abac_edge_t; |
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29 | |
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30 | // derived edge |
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31 | typedef struct _abac_derived_key_t { |
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32 | abac_vertex_t *head; |
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33 | abac_edge_t *tail; |
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34 | } abac_derived_key_t; |
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35 | |
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36 | typedef struct _abac_derived_t { |
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37 | abac_derived_key_t key; |
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38 | UT_hash_handle hh; |
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39 | } abac_derived_t; |
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40 | |
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41 | // graph |
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42 | struct _abac_graph_t { |
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43 | abac_vertex_t *vertices; |
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44 | abac_derived_t *derived; |
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45 | int dirty; |
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46 | }; |
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47 | |
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48 | // ugghhhghhhghh need this for intersections |
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49 | abac_list_t *abac_role_prereqs(abac_role_t *); |
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50 | |
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51 | /** |
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52 | * Create a new graph. |
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53 | */ |
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54 | abac_graph_t *abac_graph_new(void) { |
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55 | abac_graph_t *graph = abac_xmalloc(sizeof(abac_graph_t)); |
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56 | |
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57 | graph->vertices = NULL; |
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58 | graph->derived = NULL; |
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59 | graph->dirty = 0; |
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60 | |
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61 | return graph; |
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62 | } |
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63 | |
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64 | /** |
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65 | * Deep copy a graph. |
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66 | */ |
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67 | abac_graph_t *abac_graph_dup(abac_graph_t *graph) { |
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68 | abac_vertex_t *vertex; |
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69 | abac_edge_t *edge; |
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70 | |
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71 | abac_graph_t *clone = abac_graph_new(); |
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72 | |
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73 | // copy the vertices edge by edge |
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74 | for (vertex = graph->vertices; vertex != NULL; vertex = vertex->hh.next) |
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75 | abac_list_foreach(vertex->edges, edge, |
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76 | // only copy non-derived edges |
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77 | if (edge->credential != NULL) |
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78 | abac_graph_add_credential(clone, edge->credential); |
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79 | ); |
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80 | |
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81 | return clone; |
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82 | } |
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83 | |
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84 | /** |
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85 | * Add a vertex to the graph. Should only be called by abac_graph_add_credential. |
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86 | */ |
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87 | static abac_vertex_t *_get_vertex(abac_graph_t *graph, abac_role_t *role) { |
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88 | abac_vertex_t *vertex; |
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89 | char *string; |
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90 | |
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91 | string = abac_role_string(role); |
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92 | HASH_FIND_STR(graph->vertices, string, vertex); |
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93 | |
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94 | // add the vertex if it doesn't exist |
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95 | if (vertex == NULL) { |
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96 | vertex = abac_xmalloc(sizeof(abac_vertex_t)); |
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97 | vertex->role = abac_role_dup(role); |
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98 | vertex->name = abac_role_string(vertex->role); |
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99 | |
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100 | // create the list of edges |
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101 | vertex->edges = abac_list_new(); |
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102 | |
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103 | // for intersections, always NULL on normal vertices |
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104 | if (abac_role_is_intersection(role)) { |
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105 | abac_role_t *prereq; |
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106 | vertex->prereqs = abac_list_new(); |
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107 | |
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108 | // add each prereq to the vertex |
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109 | abac_list_foreach(abac_role_prereqs(role), prereq, |
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110 | abac_vertex_t *tail_vertex = _get_vertex(graph, prereq); |
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111 | abac_list_add(vertex->prereqs, tail_vertex); |
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112 | ); |
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113 | } |
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114 | |
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115 | // normal edges have no prereqs |
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116 | else |
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117 | vertex->prereqs = NULL; |
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118 | |
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119 | // add it to the vertices |
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120 | HASH_ADD_KEYPTR(hh, graph->vertices, vertex->name, strlen(vertex->name), vertex); |
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121 | } |
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122 | |
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123 | return vertex; |
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124 | } |
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125 | |
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126 | /** |
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127 | * Add a credential to the credential graph. |
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128 | */ |
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129 | int abac_graph_add_credential(abac_graph_t *graph, abac_credential_t *cred) { |
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130 | abac_vertex_t *head_vertex, *tail_vertex; |
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131 | abac_edge_t *edge; |
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132 | |
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133 | assert(cred != NULL); |
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134 | |
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135 | abac_role_t *head = abac_credential_head(cred); |
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136 | abac_role_t *tail = abac_credential_tail(cred); |
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137 | |
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138 | // a valid credential must have a role for the head |
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139 | if (!abac_role_is_role(head)) return 0; |
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140 | |
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141 | head_vertex = _get_vertex(graph, head); |
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142 | tail_vertex = _get_vertex(graph, tail); |
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143 | |
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144 | // make sure we don't insert the same edge twice (ugh) |
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145 | abac_list_foreach(head_vertex->edges, edge, |
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146 | if (edge->vertex == tail_vertex) |
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147 | return 0; |
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148 | ); |
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149 | |
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150 | // create the edge and add it |
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151 | edge = abac_xmalloc(sizeof(abac_edge_t)); |
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152 | edge->vertex = tail_vertex; |
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153 | edge->credential = abac_credential_dup(cred); |
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154 | |
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155 | abac_list_add(head_vertex->edges, edge); |
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156 | |
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157 | // must re-derive edges |
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158 | graph->dirty = 1; |
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159 | |
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160 | return 1; |
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161 | } |
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162 | |
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163 | // find the principals that have a role |
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164 | static abac_set_t *_find_principals(abac_graph_t *graph, abac_vertex_t *start_vertex) { |
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165 | abac_set_t *principals = abac_set_new(); |
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166 | |
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167 | abac_list_t *traversal = abac_graph_postorder(graph, start_vertex->role); |
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168 | abac_vertex_t *vertex; |
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169 | |
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170 | abac_list_foreach(traversal, vertex, |
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171 | if (abac_role_is_principal(vertex->role)) |
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172 | abac_set_add(principals, abac_role_string(vertex->role)); |
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173 | ); |
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174 | |
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175 | abac_list_free(traversal); |
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176 | return principals; |
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177 | } |
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178 | |
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179 | // remove any derived edges from the graph |
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180 | void _clear_derived(abac_graph_t *graph) { |
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181 | abac_derived_t *current; |
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182 | |
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183 | while (graph->derived) { |
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184 | current = graph->derived; |
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185 | |
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186 | HASH_DEL(graph->derived, current); |
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187 | |
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188 | abac_vertex_t *head = current->key.head; |
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189 | abac_edge_t *tail = current->key.tail; |
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190 | assert(tail->credential == NULL); |
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191 | |
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192 | // this can fail, but we assume the data structures are consistent |
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193 | abac_list_remove(head->edges, tail); |
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194 | |
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195 | free(current); |
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196 | free(tail); |
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197 | } |
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198 | } |
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199 | |
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200 | // add a derived edge, returns 1 if added 0 if dup |
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201 | static int _derived_edge(abac_graph_t *graph, abac_vertex_t *head, abac_vertex_t *tail) { |
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202 | abac_edge_t *edge; |
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203 | |
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204 | // don't add duplicate edges |
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205 | abac_list_foreach(head->edges, edge, |
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206 | if (edge->vertex == tail) |
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207 | return 0; |
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208 | ); |
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209 | |
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210 | debug_printf("derived edge %s <- %s\n", head->name, tail->name); |
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211 | |
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212 | edge = abac_xmalloc(sizeof(abac_edge_t)); |
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213 | edge->vertex = tail; |
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214 | edge->credential = NULL; |
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215 | abac_list_add(head->edges, edge); |
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216 | |
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217 | // add to list of derived edges |
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218 | abac_derived_t *derived = abac_xmalloc(sizeof(abac_derived_t)); |
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219 | derived->key.head = head; |
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220 | derived->key.tail = edge; |
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221 | HASH_ADD(hh, graph->derived, key, sizeof(abac_derived_key_t), derived); |
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222 | |
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223 | return 1; |
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224 | } |
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225 | |
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226 | // find a vertex by name |
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227 | abac_vertex_t *_find_vertex(abac_graph_t *graph, char *name) { |
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228 | abac_vertex_t *ret = NULL; |
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229 | HASH_FIND_STR(graph->vertices, name, ret); |
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230 | return ret; |
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231 | } |
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232 | |
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233 | /** |
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234 | * Single iteration of deriving new edges. Returns the number of new edges |
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235 | * added. |
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236 | */ |
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237 | static int _derive_links_iter(abac_graph_t *graph) { |
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238 | int count = 0; |
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239 | abac_vertex_t *vertex; |
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240 | |
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241 | for (vertex = graph->vertices; vertex != NULL; vertex = vertex->hh.next) { |
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242 | // intersection |
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243 | if (abac_role_is_intersection(vertex->role)) { |
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244 | // for each prereq edge: |
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245 | // find principals that have the edge |
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246 | // find intersection of all sets |
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247 | // for each principal B in intersection: |
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248 | // add link |
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249 | |
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250 | char *name; |
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251 | abac_vertex_t *prereq; |
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252 | abac_set_t *principals = NULL; |
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253 | |
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254 | abac_list_foreach(vertex->prereqs, prereq, |
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255 | abac_set_t *cur = _find_principals(graph, prereq); |
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256 | |
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257 | if (principals == NULL) |
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258 | principals = cur; |
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259 | else { |
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260 | abac_set_intersect(principals, cur); |
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261 | abac_set_free(cur); |
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262 | } |
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263 | |
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264 | if (abac_set_size(principals) == 0) |
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265 | goto isect_done; |
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266 | ); |
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267 | |
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268 | abac_list_t *prin_names = abac_set_elements(principals); |
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269 | abac_list_foreach(prin_names, name, |
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270 | abac_vertex_t *principal = _find_vertex(graph, name); |
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271 | count += _derived_edge(graph, vertex, principal); |
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272 | ); |
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273 | |
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274 | abac_list_free(prin_names); |
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275 | isect_done: |
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276 | abac_set_free(principals); |
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277 | } |
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278 | |
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279 | // linking role |
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280 | else if (abac_role_is_linking(vertex->role)) { |
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281 | // linking roles take the form A.r1.r2 |
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282 | char *A_r1 = abac_role_linked_role(vertex->role); |
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283 | char *r2 = abac_role_role_name(vertex->role); |
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284 | |
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285 | // find the linked role in the graph |
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286 | abac_vertex_t *A_r1_vertex; |
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287 | HASH_FIND_STR(graph->vertices, A_r1, A_r1_vertex); |
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288 | if (A_r1_vertex == NULL) |
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289 | continue; |
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290 | |
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291 | // find the principals that have A.r1 |
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292 | abac_set_t *principals = _find_principals(graph, A_r1_vertex); |
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293 | char *B; |
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294 | |
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295 | abac_list_t *elts = abac_set_elements(principals); |
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296 | |
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297 | // and add a link for each B.r2 to A.r1.r2 |
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298 | abac_list_foreach(elts, B, |
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299 | int B_len = strlen(B); |
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300 | int r2_len = strlen(r2); |
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301 | |
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302 | // create the string B.r2, thx C |
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303 | char *B_r2 = malloc(B_len + r2_len + 2); |
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304 | memcpy(B_r2, B, B_len); |
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305 | B_r2[B_len] = '.'; |
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306 | memcpy(B_r2 + B_len + 1, r2, r2_len); |
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307 | B_r2[B_len + r2_len + 1] = 0; |
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308 | |
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309 | // add an edge if the principal's granted it to someone |
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310 | abac_vertex_t *B_r2_vertex = _find_vertex(graph, B_r2); |
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311 | if (B_r2_vertex) { |
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312 | debug_printf("adding edge from %s to %s\n", B_r2, abac_role_string(vertex->role)); |
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313 | count += _derived_edge(graph, vertex, B_r2_vertex); |
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314 | } |
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315 | |
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316 | #ifdef DEBUG |
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317 | debug_printf(" incoming edges for %s\n", abac_role_string(vertex->role)); |
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318 | abac_edge_t *cur; |
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319 | abac_list_foreach(vertex->edges, cur, |
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320 | debug_printf(" %s (%s)\n", abac_role_string(cur->vertex->role), cur->vertex->name); |
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321 | ); |
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322 | #endif |
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323 | |
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324 | free(B_r2); |
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325 | ); |
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326 | |
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327 | abac_list_free(elts); |
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328 | abac_set_free(principals); |
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329 | } |
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330 | } |
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331 | |
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332 | return count; |
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333 | } |
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334 | |
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335 | /** |
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336 | * Derive all implied edges in the graph. These can come from linking roles |
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337 | * and intersections. |
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338 | * |
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339 | * We have to do it iteratively because derived edges can imply new edges. |
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340 | */ |
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341 | void abac_graph_derive_links(abac_graph_t *graph) { |
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342 | if (!graph->dirty) |
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343 | return; |
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344 | |
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345 | // iterate as long as new links are derived |
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346 | while (_derive_links_iter(graph) > 0) |
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347 | ; |
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348 | |
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349 | graph->dirty = 0; |
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350 | } |
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351 | |
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352 | static void _order_recurse(abac_vertex_t *vertex, abac_set_t *seen, int preorder, abac_list_t *stack) { |
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353 | abac_edge_t *incoming; |
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354 | |
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355 | // don't revisit nodes |
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356 | if (!abac_set_add(seen, abac_role_string(vertex->role))) |
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357 | return; |
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358 | |
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359 | if (preorder) |
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360 | abac_list_add(stack, vertex); |
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361 | |
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362 | // recurse along the incoming vertices |
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363 | abac_list_foreach(vertex->edges, incoming, |
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364 | _order_recurse(incoming->vertex, seen, preorder, stack); |
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365 | ); |
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366 | |
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367 | if (!preorder) |
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368 | abac_list_add(stack, vertex); |
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369 | } |
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370 | |
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371 | static abac_list_t *_order(abac_graph_t *graph, abac_role_t *start, int preorder) { |
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372 | debug_printf("%sorder at %s\n", preorder ? "pre" : "post", abac_role_string(start)); |
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373 | |
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374 | abac_vertex_t *start_vertex = _get_vertex(graph, start); |
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375 | abac_set_t *seen = abac_set_new(); |
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376 | |
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377 | // create the return list |
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378 | abac_list_t *stack = abac_list_new(); |
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379 | |
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380 | _order_recurse(start_vertex, seen, preorder, stack); |
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381 | |
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382 | abac_set_free(seen); |
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383 | |
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384 | return stack; |
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385 | } |
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386 | |
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387 | abac_list_t *abac_graph_postorder(abac_graph_t *graph, abac_role_t *start) { |
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388 | return _order(graph, start, 0); |
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389 | } |
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390 | |
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391 | /** |
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392 | * Postorder traverse the graph and return all the credentials within. |
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393 | */ |
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394 | abac_list_t *abac_graph_postorder_credentials(abac_graph_t *graph, char *start) { |
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395 | abac_vertex_t *vertex; |
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396 | abac_edge_t *incoming; |
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397 | |
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398 | // get the postorder of vertices |
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399 | abac_role_t *role = abac_role_from_string(start); |
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400 | abac_list_t *order = abac_graph_postorder(graph, role); |
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401 | |
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402 | // go through the list and dup all the credentials |
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403 | abac_list_t *credentials = abac_list_new(); |
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404 | abac_list_foreach(order, vertex, |
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405 | abac_list_foreach(vertex->edges, incoming, |
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406 | if (incoming->credential != NULL) |
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407 | abac_list_add(credentials, abac_credential_dup(incoming->credential)); |
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408 | ); |
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409 | ); |
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410 | |
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411 | abac_role_free(role); |
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412 | abac_list_free(order); |
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413 | |
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414 | return credentials; |
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415 | } |
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416 | |
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417 | static void _query(abac_graph_t *graph, char *role_name, char *principal, abac_graph_t *return_graph) { |
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418 | abac_vertex_t *vertex; |
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419 | abac_edge_t *incoming; |
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420 | |
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421 | abac_role_t *role = abac_role_from_string(role_name); |
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422 | abac_role_t *prin_role = abac_role_from_string(principal); |
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423 | |
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424 | // give up on bogus roles |
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425 | if (role == NULL || prin_role == NULL) { |
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426 | free(role); |
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427 | free(prin_role); |
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428 | return; |
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429 | } |
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430 | |
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431 | printf("\nQQQ ===> graph query with prin_role(%s) on role(%s)\n", abac_role_string(prin_role), abac_role_string(role)); |
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432 | |
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433 | abac_set_t *on_path = abac_set_new(); |
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434 | abac_set_add(on_path, abac_role_string(prin_role)); |
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435 | |
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436 | abac_list_t *traversal = abac_graph_postorder(graph, role); |
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437 | abac_list_foreach(traversal, vertex, |
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438 | abac_role_t *role = vertex->role; |
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439 | printf("\nQQQ ===> with role %s\n", abac_role_string(role)); |
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440 | |
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441 | abac_list_foreach(vertex->edges, incoming, |
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442 | abac_role_t *incoming_role = incoming->vertex->role; |
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443 | printf("\nQQQ ===> incoming role %s\n", abac_role_string(incoming_role)); |
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444 | |
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445 | if (!abac_set_contains(on_path, abac_role_string(incoming_role))) |
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446 | continue; |
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447 | |
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448 | abac_set_add(on_path, abac_role_string(role)); |
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449 | |
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450 | // get implying edges for intersection vertices |
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451 | if (abac_role_is_intersection(role)) { |
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452 | abac_vertex_t *prereq; |
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453 | abac_list_foreach(vertex->prereqs, prereq, |
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454 | printf("QQQ - prereq->name is %s\n", prereq->name); |
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455 | _query(graph, prereq->name, principal, return_graph); |
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456 | ); |
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457 | } |
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458 | |
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459 | // recursively find linked roles |
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460 | else if (abac_role_is_linking(role)) { |
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461 | char *linked_role = abac_role_linked_role(role); |
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462 | char *principal = abac_role_principal(incoming_role); |
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463 | |
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464 | printf("QQQ - recursive linked %s\n", linked_role); |
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465 | _query(graph, linked_role, principal, return_graph); |
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466 | } |
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467 | |
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468 | // add non-derived edges to the proof graph |
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469 | else |
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470 | abac_graph_add_credential(return_graph, incoming->credential); |
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471 | ); |
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472 | ); |
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473 | |
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474 | abac_list_free(traversal); |
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475 | abac_set_free(on_path); |
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476 | abac_role_free(role); |
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477 | abac_role_free(prin_role); |
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478 | } |
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479 | |
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480 | abac_graph_t *abac_graph_query(abac_graph_t *graph, char *role, char *principal) { |
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481 | abac_graph_derive_links(graph); |
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482 | |
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483 | abac_graph_t *return_graph = abac_graph_new(); |
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484 | _query(graph, role, principal, return_graph); |
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485 | abac_graph_derive_links(return_graph); |
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486 | return return_graph; |
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487 | } |
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488 | |
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489 | /** |
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490 | * Get all the credentials (attribute/issuer cert pairs) from the graph. |
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491 | */ |
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492 | abac_list_t *abac_graph_credentials(abac_graph_t *graph) { |
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493 | abac_list_t *credentials = abac_list_new(); |
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494 | |
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495 | abac_vertex_t *vertex; |
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496 | |
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497 | for (vertex = graph->vertices; vertex != NULL; vertex = vertex->hh.next) { |
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498 | abac_edge_t *edge; |
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499 | abac_list_foreach(vertex->edges, edge, |
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500 | if (edge->credential != NULL) |
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501 | abac_list_add(credentials, abac_credential_dup(edge->credential)); |
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502 | ); |
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503 | } |
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504 | |
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505 | return credentials; |
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506 | } |
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507 | |
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508 | void abac_graph_free(abac_graph_t *graph) { |
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509 | abac_vertex_t *vertex; |
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510 | abac_edge_t *edge; |
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511 | |
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512 | // kill derived edges |
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513 | _clear_derived(graph); |
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514 | |
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515 | // delete vertices |
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516 | while ((vertex = graph->vertices) != NULL) { |
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517 | HASH_DEL(graph->vertices, vertex); |
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518 | |
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519 | abac_role_free(vertex->role); |
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520 | |
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521 | abac_list_foreach(vertex->edges, edge, |
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522 | if (edge->credential != NULL) |
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523 | abac_credential_free(edge->credential); |
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524 | free(edge); |
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525 | ); |
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526 | abac_list_free(vertex->edges); |
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527 | |
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528 | // the prereq vertices will be freed by the outer while loop |
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529 | if (vertex->prereqs != NULL) |
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530 | abac_list_free(vertex->prereqs); |
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531 | |
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532 | free(vertex); |
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533 | } |
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534 | |
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535 | free(graph); |
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536 | } |
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537 | |
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538 | abac_role_t *abac_vertex_role(abac_vertex_t *vertex) { |
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539 | return vertex->role; |
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540 | } |
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