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| 1 | /* | ||
| 2 | * Copyright (c) 1996, 2011, Oracle and/or its affiliates. All rights reserved. | ||
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | ||
| 4 | * | ||
| 5 | * This code is free software; you can redistribute it and/or modify it | ||
| 6 | * under the terms of the GNU General Public License version 2 only, as | ||
| 7 | * published by the Free Software Foundation. Oracle designates this | ||
| 8 | * particular file as subject to the "Classpath" exception as provided | ||
| 9 | * by Oracle in the LICENSE file that accompanied this code. | ||
| 10 | * | ||
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT | ||
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | ||
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | ||
| 14 | * version 2 for more details (a copy is included in the LICENSE file that | ||
| 15 | * accompanied this code). | ||
| 16 | * | ||
| 17 | * You should have received a copy of the GNU General Public License version | ||
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, | ||
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | ||
| 20 | * | ||
| 21 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | ||
| 22 | * or visit www.oracle.com if you need additional information or have any | ||
| 23 | * questions. | ||
| 24 | */ | ||
| 25 | |||
| 26 | package sun.security.acl; | ||
| 27 | |||
| 28 | import java.io.*; | ||
| 29 | import java.util.*; | ||
| 30 | import java.security.Principal; | ||
| 31 | import java.security.acl.*; | ||
| 32 | |||
| 33 | /** | ||
| 34 | * An Access Control List (ACL) is encapsulated by this class. | ||
| 35 | * @author Satish Dharmaraj | ||
| 36 | */ | ||
| 37 | public class AclImpl extends OwnerImpl implements Acl { | ||
| 38 | // | ||
| 39 | // Maintain four tables. one each for positive and negative | ||
| 40 | // ACLs. One each depending on whether the entity is a group | ||
| 41 | // or principal. | ||
| 42 | // | ||
| 43 | private Hashtable<Principal, AclEntry> allowedUsersTable = | ||
| 44 | new Hashtable<>(23); | ||
| 45 | private Hashtable<Principal, AclEntry> allowedGroupsTable = | ||
| 46 | new Hashtable<>(23); | ||
| 47 | private Hashtable<Principal, AclEntry> deniedUsersTable = | ||
| 48 | new Hashtable<>(23); | ||
| 49 | private Hashtable<Principal, AclEntry> deniedGroupsTable = | ||
| 50 | new Hashtable<>(23); | ||
| 51 | private String aclName = null; | ||
| 52 | private Vector<Permission> zeroSet = new Vector<>(1,1); | ||
| 53 | |||
| 54 | |||
| 55 | /** | ||
| 56 | * Constructor for creating an empty ACL. | ||
| 57 | */ | ||
| 58 | public AclImpl(Principal owner, String name) { | ||
| 59 | super(owner); | ||
| 60 | try { | ||
| 61 | setName(owner, name); | ||
| 62 | } catch (Exception e) {} | ||
| 63 | } | ||
| 64 | |||
| 65 | /** | ||
| 66 | * Sets the name of the ACL. | ||
| 67 | * @param caller the principal who is invoking this method. | ||
| 68 | * @param name the name of the ACL. | ||
| 69 | * @exception NotOwnerException if the caller principal is | ||
| 70 | * not on the owners list of the Acl. | ||
| 71 | */ | ||
| 72 | public void setName(Principal caller, String name) | ||
| 73 | throws NotOwnerException | ||
| 74 | { | ||
| 75 | if (!isOwner(caller)) | ||
| 76 | throw new NotOwnerException(); | ||
| 77 | |||
| 78 | aclName = name; | ||
| 79 | } | ||
| 80 | |||
| 81 | /** | ||
| 82 | * Returns the name of the ACL. | ||
| 83 | * @return the name of the ACL. | ||
| 84 | */ | ||
| 85 | public String getName() { | ||
| 86 | return aclName; | ||
| 87 | } | ||
| 88 | |||
| 89 | /** | ||
| 90 | * Adds an ACL entry to this ACL. An entry associates a | ||
| 91 | * group or a principal with a set of permissions. Each | ||
| 92 | * user or group can have one positive ACL entry and one | ||
| 93 | * negative ACL entry. If there is one of the type (negative | ||
| 94 | * or positive) already in the table, a false value is returned. | ||
| 95 | * The caller principal must be a part of the owners list of | ||
| 96 | * the ACL in order to invoke this method. | ||
| 97 | * @param caller the principal who is invoking this method. | ||
| 98 | * @param entry the ACL entry that must be added to the ACL. | ||
| 99 | * @return true on success, false if the entry is already present. | ||
| 100 | * @exception NotOwnerException if the caller principal | ||
| 101 | * is not on the owners list of the Acl. | ||
| 102 | */ | ||
| 103 | public synchronized boolean addEntry(Principal caller, AclEntry entry) | ||
| 104 | throws NotOwnerException | ||
| 105 | { | ||
| 106 | if (!isOwner(caller)) | ||
| 107 | throw new NotOwnerException(); | ||
| 108 | |||
| 109 | Hashtable<Principal, AclEntry> aclTable = findTable(entry); | ||
| 110 | Principal key = entry.getPrincipal(); | ||
| 111 | |||
| 112 | if (aclTable.get(key) != null) | ||
| 113 | return false; | ||
| 114 | |||
| 115 | aclTable.put(key, entry); | ||
| 116 | return true; | ||
| 117 | } | ||
| 118 | |||
| 119 | /** | ||
| 120 | * Removes an ACL entry from this ACL. | ||
| 121 | * The caller principal must be a part of the owners list of the ACL | ||
| 122 | * in order to invoke this method. | ||
| 123 | * @param caller the principal who is invoking this method. | ||
| 124 | * @param entry the ACL entry that must be removed from the ACL. | ||
| 125 | * @return true on success, false if the entry is not part of the ACL. | ||
| 126 | * @exception NotOwnerException if the caller principal is not | ||
| 127 | * the owners list of the Acl. | ||
| 128 | */ | ||
| 129 | public synchronized boolean removeEntry(Principal caller, AclEntry entry) | ||
| 130 | throws NotOwnerException | ||
| 131 | { | ||
| 132 | if (!isOwner(caller)) | ||
| 133 | throw new NotOwnerException(); | ||
| 134 | |||
| 135 | Hashtable<Principal, AclEntry> aclTable = findTable(entry); | ||
| 136 | Principal key = entry.getPrincipal(); | ||
| 137 | |||
| 138 | AclEntry o = aclTable.remove(key); | ||
| 139 | return (o != null); | ||
| 140 | } | ||
| 141 | |||
| 142 | /** | ||
| 143 | * This method returns the set of allowed permissions for the | ||
| 144 | * specified principal. This set of allowed permissions is calculated | ||
| 145 | * as follows: | ||
| 146 | * | ||
| 147 | * If there is no entry for a group or a principal an empty permission | ||
| 148 | * set is assumed. | ||
| 149 | * | ||
| 150 | * The group positive permission set is the union of all | ||
| 151 | * the positive permissions of each group that the individual belongs to. | ||
| 152 | * The group negative permission set is the union of all | ||
| 153 | * the negative permissions of each group that the individual belongs to. | ||
| 154 | * If there is a specific permission that occurs in both | ||
| 155 | * the postive permission set and the negative permission set, | ||
| 156 | * it is removed from both. The group positive and negatoive permission | ||
| 157 | * sets are calculated. | ||
| 158 | * | ||
| 159 | * The individial positive permission set and the individual negative | ||
| 160 | * permission set is then calculated. Again abscence of an entry means | ||
| 161 | * the empty set. | ||
| 162 | * | ||
| 163 | * The set of permissions granted to the principal is then calculated using | ||
| 164 | * the simple rule: Individual permissions always override the Group permissions. | ||
| 165 | * Specifically, individual negative permission set (specific | ||
| 166 | * denial of permissions) overrides the group positive permission set. | ||
| 167 | * And the individual positive permission set override the group negative | ||
| 168 | * permission set. | ||
| 169 | * | ||
| 170 | * @param user the principal for which the ACL entry is returned. | ||
| 171 | * @return The resulting permission set that the principal is allowed. | ||
| 172 | */ | ||
| 173 | public synchronized Enumeration<Permission> getPermissions(Principal user) { | ||
| 174 | |||
| 175 | Enumeration<Permission> individualPositive; | ||
| 176 | Enumeration<Permission> individualNegative; | ||
| 177 | Enumeration<Permission> groupPositive; | ||
| 178 | Enumeration<Permission> groupNegative; | ||
| 179 | |||
| 180 | // | ||
| 181 | // canonicalize the sets. That is remove common permissions from | ||
| 182 | // positive and negative sets. | ||
| 183 | // | ||
| 184 | groupPositive = | ||
| 185 | subtract(getGroupPositive(user), getGroupNegative(user)); | ||
| 186 | groupNegative = | ||
| 187 | subtract(getGroupNegative(user), getGroupPositive(user)); | ||
| 188 | individualPositive = | ||
| 189 | subtract(getIndividualPositive(user), getIndividualNegative(user)); | ||
| 190 | individualNegative = | ||
| 191 | subtract(getIndividualNegative(user), getIndividualPositive(user)); | ||
| 192 | |||
| 193 | // | ||
| 194 | // net positive permissions is individual positive permissions | ||
| 195 | // plus (group positive - individual negative). | ||
| 196 | // | ||
| 197 | Enumeration<Permission> temp1 = | ||
| 198 | subtract(groupPositive, individualNegative); | ||
| 199 | Enumeration<Permission> netPositive = | ||
| 200 | union(individualPositive, temp1); | ||
| 201 | |||
| 202 | // recalculate the enumeration since we lost it in performing the | ||
| 203 | // subtraction | ||
| 204 | // | ||
| 205 | individualPositive = | ||
| 206 | subtract(getIndividualPositive(user), getIndividualNegative(user)); | ||
| 207 | individualNegative = | ||
| 208 | subtract(getIndividualNegative(user), getIndividualPositive(user)); | ||
| 209 | |||
| 210 | // | ||
| 211 | // net negative permissions is individual negative permissions | ||
| 212 | // plus (group negative - individual positive). | ||
| 213 | // | ||
| 214 | temp1 = subtract(groupNegative, individualPositive); | ||
| 215 | Enumeration<Permission> netNegative = union(individualNegative, temp1); | ||
| 216 | |||
| 217 | return subtract(netPositive, netNegative); | ||
| 218 | } | ||
| 219 | |||
| 220 | /** | ||
| 221 | * This method checks whether or not the specified principal | ||
| 222 | * has the required permission. If permission is denied | ||
| 223 | * permission false is returned, a true value is returned otherwise. | ||
| 224 | * This method does not authenticate the principal. It presumes that | ||
| 225 | * the principal is a valid authenticated principal. | ||
| 226 | * @param principal the name of the authenticated principal | ||
| 227 | * @param permission the permission that the principal must have. | ||
| 228 | * @return true of the principal has the permission desired, false | ||
| 229 | * otherwise. | ||
| 230 | */ | ||
| 231 | public boolean checkPermission(Principal principal, Permission permission) | ||
| 232 | { | ||
| 233 | Enumeration<Permission> permSet = getPermissions(principal); | ||
| 234 | while (permSet.hasMoreElements()) { | ||
| 235 | Permission p = permSet.nextElement(); | ||
| 236 | if (p.equals(permission)) | ||
| 237 | return true; | ||
| 238 | } | ||
| 239 | return false; | ||
| 240 | } | ||
| 241 | |||
| 242 | /** | ||
| 243 | * returns an enumeration of the entries in this ACL. | ||
| 244 | */ | ||
| 245 | public synchronized Enumeration<AclEntry> entries() { | ||
| 246 | return new AclEnumerator(this, | ||
| 247 | allowedUsersTable, allowedGroupsTable, | ||
| 248 | deniedUsersTable, deniedGroupsTable); | ||
| 249 | } | ||
| 250 | |||
| 251 | /** | ||
| 252 | * return a stringified version of the | ||
| 253 | * ACL. | ||
| 254 | */ | ||
| 255 | public String toString() { | ||
| 256 | StringBuffer sb = new StringBuffer(); | ||
| 257 | Enumeration<AclEntry> entries = entries(); | ||
| 258 | while (entries.hasMoreElements()) { | ||
| 259 | AclEntry entry = entries.nextElement(); | ||
| 260 | sb.append(entry.toString().trim()); | ||
| 261 | sb.append("\n"); | ||
| 262 | } | ||
| 263 | |||
| 264 | return sb.toString(); | ||
| 265 | } | ||
| 266 | |||
| 267 | // | ||
| 268 | // Find the table that this entry belongs to. There are 4 | ||
| 269 | // tables that are maintained. One each for postive and | ||
| 270 | // negative ACLs and one each for groups and users. | ||
| 271 | // This method figures out which | ||
| 272 | // table is the one that this AclEntry belongs to. | ||
| 273 | // | ||
| 274 | private Hashtable<Principal, AclEntry> findTable(AclEntry entry) { | ||
| 275 | Hashtable<Principal, AclEntry> aclTable = null; | ||
| 276 | |||
| 277 | Principal p = entry.getPrincipal(); | ||
| 278 | if (p instanceof Group) { | ||
| 279 | if (entry.isNegative()) | ||
| 280 | aclTable = deniedGroupsTable; | ||
| 281 | else | ||
| 282 | aclTable = allowedGroupsTable; | ||
| 283 | } else { | ||
| 284 | if (entry.isNegative()) | ||
| 285 | aclTable = deniedUsersTable; | ||
| 286 | else | ||
| 287 | aclTable = allowedUsersTable; | ||
| 288 | } | ||
| 289 | return aclTable; | ||
| 290 | } | ||
| 291 | |||
| 292 | // | ||
| 293 | // returns the set e1 U e2. | ||
| 294 | // | ||
| 295 | private static Enumeration<Permission> union(Enumeration<Permission> e1, | ||
| 296 | Enumeration<Permission> e2) { | ||
| 297 | Vector<Permission> v = new Vector<>(20, 20); | ||
| 298 | |||
| 299 | while (e1.hasMoreElements()) | ||
| 300 | v.addElement(e1.nextElement()); | ||
| 301 | |||
| 302 | while (e2.hasMoreElements()) { | ||
| 303 | Permission o = e2.nextElement(); | ||
| 304 | if (!v.contains(o)) | ||
| 305 | v.addElement(o); | ||
| 306 | } | ||
| 307 | |||
| 308 | return v.elements(); | ||
| 309 | } | ||
| 310 | |||
| 311 | // | ||
| 312 | // returns the set e1 - e2. | ||
| 313 | // | ||
| 314 | private Enumeration<Permission> subtract(Enumeration<Permission> e1, | ||
| 315 | Enumeration<Permission> e2) { | ||
| 316 | Vector<Permission> v = new Vector<>(20, 20); | ||
| 317 | |||
| 318 | while (e1.hasMoreElements()) | ||
| 319 | v.addElement(e1.nextElement()); | ||
| 320 | |||
| 321 | while (e2.hasMoreElements()) { | ||
| 322 | Permission o = e2.nextElement(); | ||
| 323 | if (v.contains(o)) | ||
| 324 | v.removeElement(o); | ||
| 325 | } | ||
| 326 | |||
| 327 | return v.elements(); | ||
| 328 | } | ||
| 329 | |||
| 330 | private Enumeration<Permission> getGroupPositive(Principal user) { | ||
| 331 | Enumeration<Permission> groupPositive = zeroSet.elements(); | ||
| 332 | Enumeration<Principal> e = allowedGroupsTable.keys(); | ||
| 333 | while (e.hasMoreElements()) { | ||
| 334 | Group g = (Group)e.nextElement(); | ||
| 335 | if (g.isMember(user)) { | ||
| 336 | AclEntry ae = allowedGroupsTable.get(g); | ||
| 337 | groupPositive = union(ae.permissions(), groupPositive); | ||
| 338 | } | ||
| 339 | } | ||
| 340 | return groupPositive; | ||
| 341 | } | ||
| 342 | |||
| 343 | private Enumeration<Permission> getGroupNegative(Principal user) { | ||
| 344 | Enumeration<Permission> groupNegative = zeroSet.elements(); | ||
| 345 | Enumeration<Principal> e = deniedGroupsTable.keys(); | ||
| 346 | while (e.hasMoreElements()) { | ||
| 347 | Group g = (Group)e.nextElement(); | ||
| 348 | if (g.isMember(user)) { | ||
| 349 | AclEntry ae = deniedGroupsTable.get(g); | ||
| 350 | groupNegative = union(ae.permissions(), groupNegative); | ||
| 351 | } | ||
| 352 | } | ||
| 353 | return groupNegative; | ||
| 354 | } | ||
| 355 | |||
| 356 | private Enumeration<Permission> getIndividualPositive(Principal user) { | ||
| 357 | Enumeration<Permission> individualPositive = zeroSet.elements(); | ||
| 358 | AclEntry ae = allowedUsersTable.get(user); | ||
| 359 | if (ae != null) | ||
| 360 | individualPositive = ae.permissions(); | ||
| 361 | return individualPositive; | ||
| 362 | } | ||
| 363 | |||
| 364 | private Enumeration<Permission> getIndividualNegative(Principal user) { | ||
| 365 | Enumeration<Permission> individualNegative = zeroSet.elements(); | ||
| 366 | AclEntry ae = deniedUsersTable.get(user); | ||
| 367 | if (ae != null) | ||
| 368 | individualNegative = ae.permissions(); | ||
| 369 | return individualNegative; | ||
| 370 | } | ||
| 371 | } | ||
| 372 | |||
| 373 | final class AclEnumerator implements Enumeration<AclEntry> { | ||
| 374 | Acl acl; | ||
| 375 | Enumeration<AclEntry> u1, u2, g1, g2; | ||
| 376 | |||
| 377 | AclEnumerator(Acl acl, Hashtable<?,AclEntry> u1, Hashtable<?,AclEntry> g1, | ||
| 378 | Hashtable<?,AclEntry> u2, Hashtable<?,AclEntry> g2) { | ||
| 379 | this.acl = acl; | ||
| 380 | this.u1 = u1.elements(); | ||
| 381 | this.u2 = u2.elements(); | ||
| 382 | this.g1 = g1.elements(); | ||
| 383 | this.g2 = g2.elements(); | ||
| 384 | } | ||
| 385 | |||
| 386 | public boolean hasMoreElements() { | ||
| 387 | return (u1.hasMoreElements() || | ||
| 388 | u2.hasMoreElements() || | ||
| 389 | g1.hasMoreElements() || | ||
| 390 | g2.hasMoreElements()); | ||
| 391 | } | ||
| 392 | |||
| 393 | public AclEntry nextElement() | ||
| 394 | { | ||
| 395 | AclEntry o; | ||
| 396 | synchronized (acl) { | ||
| 397 | if (u1.hasMoreElements()) | ||
| 398 | return u1.nextElement(); | ||
| 399 | if (u2.hasMoreElements()) | ||
| 400 | return u2.nextElement(); | ||
| 401 | if (g1.hasMoreElements()) | ||
| 402 | return g1.nextElement(); | ||
| 403 | if (g2.hasMoreElements()) | ||
| 404 | return g2.nextElement(); | ||
| 405 | } | ||
| 406 | throw new NoSuchElementException("Acl Enumerator"); | ||
| 407 | } | ||
| 408 | } | ||