1 /*
2 * Copyright (c) 2010, 2012, 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.krb5;
27
28 import java.io.IOException;
29 import java.util.Arrays;
30 import javax.security.auth.kerberos.KeyTab;
31 import sun.security.jgss.krb5.Krb5Util;
32 import sun.security.krb5.internal.HostAddresses;
33 import sun.security.krb5.internal.KDCOptions;
34 import sun.security.krb5.internal.KRBError;
35 import sun.security.krb5.internal.KerberosTime;
36 import sun.security.krb5.internal.Krb5;
37 import sun.security.krb5.internal.PAData;
38 import sun.security.krb5.internal.crypto.EType;
39
40 /**
41 * A manager class for AS-REQ communications.
42 *
43 * This class does:
44 * 1. Gather information to create AS-REQ
45 * 2. Create and send AS-REQ
46 * 3. Receive AS-REP and KRB-ERROR (-KRB_ERR_RESPONSE_TOO_BIG) and parse them
47 * 4. Emit credentials and secret keys (for JAAS storeKey=true with password)
48 *
49 * This class does not:
50 * 1. Deal with real communications (KdcComm does it, and TGS-REQ)
51 * a. Name of KDCs for a realm
52 * b. Server availability, timeout, UDP or TCP
53 * d. KRB_ERR_RESPONSE_TOO_BIG
54 * 2. Stores its own copy of password, this means:
55 * a. Do not change/wipe it before Builder finish
56 * b. Builder will not wipe it for you
57 *
58 * With this class:
59 * 1. KrbAsReq has only one constructor
60 * 2. Krb5LoginModule and Kinit call a single builder
61 * 3. Better handling of sensitive info
62 *
63 * @since 1.7
64 */
65
66 public final class KrbAsReqBuilder {
67
68 // Common data for AS-REQ fields
69 private KDCOptions options;
70 private PrincipalName cname;
71 private PrincipalName sname;
72 private KerberosTime from;
73 private KerberosTime till;
74 private KerberosTime rtime;
75 private HostAddresses addresses;
76
77 // Secret source: can't be changed once assigned, only one (of the two
78 // sources) can be set to non-null
79 private final char[] password;
80 private final KeyTab ktab;
81
82 // Used to create a ENC-TIMESTAMP in the 2nd AS-REQ
83 private PAData[] paList; // PA-DATA from both KRB-ERROR and AS-REP.
84 // Used by getKeys() only.
85 // Only AS-REP should be enough per RFC,
86 // combined in case etypes are different.
87
88 // The generated and received:
89 private KrbAsReq req;
90 private KrbAsRep rep;
91
92 private static enum State {
93 INIT, // Initialized, can still add more initialization info
94 REQ_OK, // AS-REQ performed
95 DESTROYED, // Destroyed, not usable anymore
96 }
97 private State state;
98
99 // Called by other constructors
100 private void init(PrincipalName cname)
101 throws KrbException {
102 this.cname = cname;
103 state = State.INIT;
104 }
105
106 /**
107 * Creates a builder to be used by {@code cname} with existing keys.
108 *
109 * @param cname the client of the AS-REQ. Must not be null. Might have no
110 * realm, where default realm will be used. This realm will be the target
111 * realm for AS-REQ. I believe a client should only get initial TGT from
112 * its own realm.
113 * @param ktab must not be null. If empty, might be quite useless.
114 * This argument will neither be modified nor stored by the method.
115 * @throws KrbException
116 */
117 public KrbAsReqBuilder(PrincipalName cname, KeyTab ktab)
118 throws KrbException {
119 init(cname);
120 this.ktab = ktab;
121 this.password = null;
122 }
123
124 /**
125 * Creates a builder to be used by {@code cname} with a known password.
126 *
127 * @param cname the client of the AS-REQ. Must not be null. Might have no
128 * realm, where default realm will be used. This realm will be the target
129 * realm for AS-REQ. I believe a client should only get initial TGT from
130 * its own realm.
131 * @param pass must not be null. This argument will neither be modified
132 * nor stored by the method.
133 * @throws KrbException
134 */
135 public KrbAsReqBuilder(PrincipalName cname, char[] pass)
136 throws KrbException {
137 init(cname);
138 this.password = pass.clone();
139 this.ktab = null;
140 }
141
142 /**
143 * Retrieves an array of secret keys for the client. This is used when
144 * the client supplies password but need keys to act as an acceptor. For
145 * an initiator, it must be called after AS-REQ is performed (state is OK).
146 * For an acceptor, it can be called when this KrbAsReqBuilder object is
147 * constructed (state is INIT).
148 * @param isInitiator if the caller is an initiator
149 * @return generated keys from password. PA-DATA from server might be used.
150 * All "default_tkt_enctypes" keys will be generated, Never null.
151 * @throws IllegalStateException if not constructed from a password
152 * @throws KrbException
153 */
154 public EncryptionKey[] getKeys(boolean isInitiator) throws KrbException {
155 checkState(isInitiator?State.REQ_OK:State.INIT, "Cannot get keys");
156 if (password != null) {
157 int[] eTypes = EType.getDefaults("default_tkt_enctypes");
158 EncryptionKey[] result = new EncryptionKey[eTypes.length];
159
160 /*
161 * Returns an array of keys. Before KrbAsReqBuilder, all etypes
162 * use the same salt which is either the default one or a new salt
163 * coming from PA-DATA. After KrbAsReqBuilder, each etype uses its
164 * own new salt from PA-DATA. For an etype with no PA-DATA new salt
165 * at all, what salt should it use?
166 *
167 * Commonly, the stored keys are only to be used by an acceptor to
168 * decrypt service ticket in AP-REQ. Most impls only allow keys
169 * from a keytab on acceptor, but unfortunately (?) Java supports
170 * acceptor using password. In this case, if the service ticket is
171 * encrypted using an etype which we don't have PA-DATA new salt,
172 * using the default salt might be wrong (say, case-insensitive
173 * user name). Instead, we would use the new salt of another etype.
174 */
175
176 String salt = null; // the saved new salt
177 try {
178 for (int i=0; i<eTypes.length; i++) {
179 // First round, only calculate those have a PA entry
180 PAData.SaltAndParams snp =
181 PAData.getSaltAndParams(eTypes[i], paList);
182 if (snp != null) {
183 // Never uses a salt for rc4-hmac, it does not use
184 // a salt at all
185 if (eTypes[i] != EncryptedData.ETYPE_ARCFOUR_HMAC &&
186 snp.salt != null) {
187 salt = snp.salt;
188 }
189 result[i] = EncryptionKey.acquireSecretKey(cname,
190 password,
191 eTypes[i],
192 snp);
193 }
194 }
195 // No new salt from PA, maybe empty, maybe only rc4-hmac
196 if (salt == null) salt = cname.getSalt();
197 for (int i=0; i<eTypes.length; i++) {
198 // Second round, calculate those with no PA entry
199 if (result[i] == null) {
200 result[i] = EncryptionKey.acquireSecretKey(password,
201 salt,
202 eTypes[i],
203 null);
204 }
205 }
206 } catch (IOException ioe) {
207 KrbException ke = new KrbException(Krb5.ASN1_PARSE_ERROR);
208 ke.initCause(ioe);
209 throw ke;
210 }
211 return result;
212 } else {
213 throw new IllegalStateException("Required password not provided");
214 }
215 }
216
217 /**
218 * Sets or clears options. If cleared, default options will be used
219 * at creation time.
220 * @param options
221 */
222 public void setOptions(KDCOptions options) {
223 checkState(State.INIT, "Cannot specify options");
224 this.options = options;
225 }
226
227 public void setTill(KerberosTime till) {
228 checkState(State.INIT, "Cannot specify till");
229 this.till = till;
230 }
231
232 public void setRTime(KerberosTime rtime) {
233 checkState(State.INIT, "Cannot specify rtime");
234 this.rtime = rtime;
235 }
236
237 /**
238 * Sets or clears target. If cleared, KrbAsReq might choose krbtgt
239 * for cname realm
240 * @param sname
241 */
242 public void setTarget(PrincipalName sname) {
243 checkState(State.INIT, "Cannot specify target");
244 this.sname = sname;
245 }
246
247 /**
248 * Adds or clears addresses. KrbAsReq might add some if empty
249 * field not allowed
250 * @param addresses
251 */
252 public void setAddresses(HostAddresses addresses) {
253 checkState(State.INIT, "Cannot specify addresses");
254 this.addresses = addresses;
255 }
256
257 /**
258 * Build a KrbAsReq object from all info fed above. Normally this method
259 * will be called twice: initial AS-REQ and second with pakey
260 * @param key null (initial AS-REQ) or pakey (with preauth)
261 * @return the KrbAsReq object
262 * @throws KrbException
263 * @throws IOException
264 */
265 private KrbAsReq build(EncryptionKey key) throws KrbException, IOException {
266 int[] eTypes;
267 if (password != null) {
268 eTypes = EType.getDefaults("default_tkt_enctypes");
269 } else {
270 EncryptionKey[] ks = Krb5Util.keysFromJavaxKeyTab(ktab, cname);
271 eTypes = EType.getDefaults("default_tkt_enctypes",
272 ks);
273 for (EncryptionKey k: ks) k.destroy();
274 }
275 return new KrbAsReq(key,
276 options,
277 cname,
278 sname,
279 from,
280 till,
281 rtime,
282 eTypes,
283 addresses);
284 }
285
286 /**
287 * Parses AS-REP, decrypts enc-part, retrieves ticket and session key
288 * @throws KrbException
289 * @throws Asn1Exception
290 * @throws IOException
291 */
292 private KrbAsReqBuilder resolve()
293 throws KrbException, Asn1Exception, IOException {
294 if (ktab != null) {
295 rep.decryptUsingKeyTab(ktab, req, cname);
296 } else {
297 rep.decryptUsingPassword(password, req, cname);
298 }
299 if (rep.getPA() != null) {
300 if (paList == null || paList.length == 0) {
301 paList = rep.getPA();
302 } else {
303 int extraLen = rep.getPA().length;
304 if (extraLen > 0) {
305 int oldLen = paList.length;
306 paList = Arrays.copyOf(paList, paList.length + extraLen);
307 System.arraycopy(rep.getPA(), 0, paList, oldLen, extraLen);
308 }
309 }
310 }
311 return this;
312 }
313
314 /**
315 * Communication until AS-REP or non preauth-related KRB-ERROR received
316 * @throws KrbException
317 * @throws IOException
318 */
319 private KrbAsReqBuilder send() throws KrbException, IOException {
320 boolean preAuthFailedOnce = false;
321 KdcComm comm = new KdcComm(cname.getRealmAsString());
322 EncryptionKey pakey = null;
323 while (true) {
324 try {
325 req = build(pakey);
326 rep = new KrbAsRep(comm.send(req.encoding()));
327 return this;
328 } catch (KrbException ke) {
329 if (!preAuthFailedOnce && (
330 ke.returnCode() == Krb5.KDC_ERR_PREAUTH_FAILED ||
331 ke.returnCode() == Krb5.KDC_ERR_PREAUTH_REQUIRED)) {
332 if (Krb5.DEBUG) {
333 System.out.println("KrbAsReqBuilder: " +
334 "PREAUTH FAILED/REQ, re-send AS-REQ");
335 }
336 preAuthFailedOnce = true;
337 KRBError kerr = ke.getError();
338 int paEType = PAData.getPreferredEType(kerr.getPA(),
339 EType.getDefaults("default_tkt_enctypes")[0]);
340 if (password == null) {
341 EncryptionKey[] ks = Krb5Util.keysFromJavaxKeyTab(ktab, cname);
342 pakey = EncryptionKey.findKey(paEType, ks);
343 if (pakey != null) pakey = (EncryptionKey)pakey.clone();
344 for (EncryptionKey k: ks) k.destroy();
345 } else {
346 pakey = EncryptionKey.acquireSecretKey(cname,
347 password,
348 paEType,
349 PAData.getSaltAndParams(
350 paEType, kerr.getPA()));
351 }
352 paList = kerr.getPA(); // Update current paList
353 } else {
354 throw ke;
355 }
356 }
357 }
358 }
359
360 /**
361 * Performs AS-REQ send and AS-REP receive.
362 * Maybe a state is needed here, to divide prepare process and getCreds.
363 * @throws KrbException
364 * @throws Asn1Exception
365 * @throws IOException
366 */
367 public KrbAsReqBuilder action()
368 throws KrbException, Asn1Exception, IOException {
369 checkState(State.INIT, "Cannot call action");
370 state = State.REQ_OK;
371 return send().resolve();
372 }
373
374 /**
375 * Gets Credentials object after action
376 */
377 public Credentials getCreds() {
378 checkState(State.REQ_OK, "Cannot retrieve creds");
379 return rep.getCreds();
380 }
381
382 /**
383 * Gets another type of Credentials after action
384 */
385 public sun.security.krb5.internal.ccache.Credentials getCCreds() {
386 checkState(State.REQ_OK, "Cannot retrieve CCreds");
387 return rep.getCCreds();
388 }
389
390 /**
391 * Destroys the object and clears keys and password info.
392 */
393 public void destroy() {
394 state = State.DESTROYED;
395 if (password != null) {
396 Arrays.fill(password, (char)0);
397 }
398 }
399
400 /**
401 * Checks if the current state is the specified one.
402 * @param st the expected state
403 * @param msg error message if state is not correct
404 * @throws IllegalStateException if state is not correct
405 */
406 private void checkState(State st, String msg) {
407 if (state != st) {
408 throw new IllegalStateException(msg + " at " + st + " state");
409 }
410 }
411 }