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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one
3    * or more contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  The ASF licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   *     http://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing,
13   * software distributed under the License is distributed on an
14   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   * KIND, either express or implied.  See the License for the
16   * specific language governing permissions and limitations
17   * under the License.
18   */
19  package org.apache.shiro.mgt;
20  
21  import org.apache.shiro.authc.AuthenticationException;
22  import org.apache.shiro.authc.AuthenticationInfo;
23  import org.apache.shiro.authc.AuthenticationToken;
24  import org.apache.shiro.authc.RememberMeAuthenticationToken;
25  import org.apache.shiro.codec.Base64;
26  import org.apache.shiro.crypto.AesCipherService;
27  import org.apache.shiro.crypto.CipherService;
28  import org.apache.shiro.io.DefaultSerializer;
29  import org.apache.shiro.io.Serializer;
30  import org.apache.shiro.subject.PrincipalCollection;
31  import org.apache.shiro.subject.Subject;
32  import org.apache.shiro.subject.SubjectContext;
33  import org.apache.shiro.util.ByteSource;
34  import org.slf4j.Logger;
35  import org.slf4j.LoggerFactory;
36  
37  /**
38   * Abstract implementation of the {@code RememberMeManager} interface that handles
39   * {@link #setSerializer(org.apache.shiro.io.Serializer) serialization} and
40   * {@link #setCipherService encryption} of the remembered user identity.
41   * <p/>
42   * The remembered identity storage location and details are left to subclasses.
43   * <h2>Default encryption key</h2>
44   * This implementation uses an {@link AesCipherService AesCipherService} for strong encryption by default.  It also
45   * uses a default generated symmetric key to both encrypt and decrypt data.  As AES is a symmetric cipher, the same
46   * {@code key} is used to both encrypt and decrypt data, BUT NOTE:
47   * <p/>
48   * Because Shiro is an open-source project, if anyone knew that you were using Shiro's default
49   * {@code key}, they could download/view the source, and with enough effort, reconstruct the {@code key}
50   * and decode encrypted data at will.
51   * <p/>
52   * Of course, this key is only really used to encrypt the remembered {@code PrincipalCollection} which is typically
53   * a user id or username.  So if you do not consider that sensitive information, and you think the default key still
54   * makes things 'sufficiently difficult', then you can ignore this issue.
55   * <p/>
56   * However, if you do feel this constitutes sensitive information, it is recommended that you provide your own
57   * {@code key} via the {@link #setCipherKey setCipherKey} method to a key known only to your application,
58   * guaranteeing that no third party can decrypt your data.  You can generate your own key by calling the
59   * {@code CipherService}'s {@link org.apache.shiro.crypto.AesCipherService#generateNewKey() generateNewKey} method
60   * and using that result as the {@link #setCipherKey cipherKey} configuration attribute.
61   *
62   * @since 0.9
63   */
64  public abstract class AbstractRememberMeManager implements RememberMeManager {
65  
66      /**
67       * private inner log instance.
68       */
69      private static final Logger log = LoggerFactory.getLogger(AbstractRememberMeManager.class);
70  
71      /**
72       * Serializer to use for converting PrincipalCollection instances to/from byte arrays
73       */
74      private Serializer<PrincipalCollection> serializer;
75  
76      /**
77       * Cipher to use for encrypting/decrypting serialized byte arrays for added security
78       */
79      private CipherService cipherService;
80  
81      /**
82       * Cipher encryption key to use with the Cipher when encrypting data
83       */
84      private byte[] encryptionCipherKey;
85  
86      /**
87       * Cipher decryption key to use with the Cipher when decrypting data
88       */
89      private byte[] decryptionCipherKey;
90  
91      /**
92       * Default constructor that initializes a {@link DefaultSerializer} as the {@link #getSerializer() serializer} and
93       * an {@link AesCipherService} as the {@link #getCipherService() cipherService}.
94       */
95      public AbstractRememberMeManager() {
96          this.serializer = new DefaultSerializer<PrincipalCollection>();
97          AesCipherService cipherService = new AesCipherService();
98          this.cipherService = cipherService;
99          setCipherKey(cipherService.generateNewKey().getEncoded());
100     }
101 
102     /**
103      * Returns the {@code Serializer} used to serialize and deserialize {@link PrincipalCollection} instances for
104      * persistent remember me storage.
105      * <p/>
106      * Unless overridden by the {@link #setSerializer} method, the default instance is a
107      * {@link org.apache.shiro.io.DefaultSerializer}.
108      *
109      * @return the {@code Serializer} used to serialize and deserialize {@link PrincipalCollection} instances for
110      *         persistent remember me storage.
111      */
112     public Serializer<PrincipalCollection> getSerializer() {
113         return serializer;
114     }
115 
116     /**
117      * Sets the {@code Serializer} used to serialize and deserialize {@link PrincipalCollection} instances for
118      * persistent remember me storage.
119      * <p/>
120      * Unless overridden by this method, the default instance is a {@link DefaultSerializer}.
121      *
122      * @param serializer the {@code Serializer} used to serialize and deserialize {@link PrincipalCollection} instances
123      *                   for persistent remember me storage.
124      */
125     public void setSerializer(Serializer<PrincipalCollection> serializer) {
126         this.serializer = serializer;
127     }
128 
129     /**
130      * Returns the {@code CipherService} to use for encrypting and decrypting serialized identity data to prevent easy
131      * inspection of Subject identity data.
132      * <p/>
133      * Unless overridden by the {@link #setCipherService} method, the default instance is an {@link AesCipherService}.
134      *
135      * @return the {@code Cipher} to use for encrypting and decrypting serialized identity data to prevent easy
136      *         inspection of Subject identity data
137      */
138     public CipherService getCipherService() {
139         return cipherService;
140     }
141 
142     /**
143      * Sets the {@code CipherService} to use for encrypting and decrypting serialized identity data to prevent easy
144      * inspection of Subject identity data.
145      * <p/>
146      * If the CipherService is a symmetric CipherService (using the same key for both encryption and decryption), you
147      * should set your key via the {@link #setCipherKey(byte[])} method.
148      * <p/>
149      * If the CipherService is an asymmetric CipherService (different keys for encryption and decryption, such as
150      * public/private key pairs), you should set your encryption and decryption key via the respective
151      * {@link #setEncryptionCipherKey(byte[])} and {@link #setDecryptionCipherKey(byte[])} methods.
152      * <p/>
153      * <b>N.B.</b> Unless overridden by this method, the default CipherService instance is an
154      * {@link AesCipherService}.  This {@code RememberMeManager} implementation already has a configured symmetric key
155      * to use for encryption and decryption, but it is recommended to provide your own for added security.  See the
156      * class-level JavaDoc for more information and why it might be good to provide your own.
157      *
158      * @param cipherService the {@code CipherService} to use for encrypting and decrypting serialized identity data to
159      *                      prevent easy inspection of Subject identity data.
160      */
161     public void setCipherService(CipherService cipherService) {
162         this.cipherService = cipherService;
163     }
164 
165     /**
166      * Returns the cipher key to use for encryption operations.
167      *
168      * @return the cipher key to use for encryption operations.
169      * @see #setCipherService for a description of the various {@code get/set*Key} methods.
170      */
171     public byte[] getEncryptionCipherKey() {
172         return encryptionCipherKey;
173     }
174 
175     /**
176      * Sets the encryption key to use for encryption operations.
177      *
178      * @param encryptionCipherKey the encryption key to use for encryption operations.
179      * @see #setCipherService for a description of the various {@code get/set*Key} methods.
180      */
181     public void setEncryptionCipherKey(byte[] encryptionCipherKey) {
182         this.encryptionCipherKey = encryptionCipherKey;
183     }
184 
185     /**
186      * Returns the decryption cipher key to use for decryption operations.
187      *
188      * @return the cipher key to use for decryption operations.
189      * @see #setCipherService for a description of the various {@code get/set*Key} methods.
190      */
191     public byte[] getDecryptionCipherKey() {
192         return decryptionCipherKey;
193     }
194 
195     /**
196      * Sets the decryption key to use for decryption operations.
197      *
198      * @param decryptionCipherKey the decryption key to use for decryption operations.
199      * @see #setCipherService for a description of the various {@code get/set*Key} methods.
200      */
201     public void setDecryptionCipherKey(byte[] decryptionCipherKey) {
202         this.decryptionCipherKey = decryptionCipherKey;
203     }
204 
205     /**
206      * Convenience method that returns the cipher key to use for <em>both</em> encryption and decryption.
207      * <p/>
208      * <b>N.B.</b> This method can only be called if the underlying {@link #getCipherService() cipherService} is a symmetric
209      * CipherService which by definition uses the same key for both encryption and decryption.  If using an asymmetric
210      * CipherService public/private key pair, you cannot use this method, and should instead use the
211      * {@link #getEncryptionCipherKey()} and {@link #getDecryptionCipherKey()} methods individually.
212      * <p/>
213      * The default {@link AesCipherService} instance is a symmetric cipher service, so this method can be used if you are
214      * using the default.
215      *
216      * @return the symmetric cipher key used for both encryption and decryption.
217      */
218     public byte[] getCipherKey() {
219         //Since this method should only be used with symmetric ciphers
220         //(where the enc and dec keys are the same), either is fine, just return one of them:
221         return getEncryptionCipherKey();
222     }
223 
224     /**
225      * Convenience method that sets the cipher key to use for <em>both</em> encryption and decryption.
226      * <p/>
227      * <b>N.B.</b> This method can only be called if the underlying {@link #getCipherService() cipherService} is a
228      * symmetric CipherService?which by definition uses the same key for both encryption and decryption.  If using an
229      * asymmetric CipherService?(such as a public/private key pair), you cannot use this method, and should instead use
230      * the {@link #setEncryptionCipherKey(byte[])} and {@link #setDecryptionCipherKey(byte[])} methods individually.
231      * <p/>
232      * The default {@link AesCipherService} instance is a symmetric CipherService, so this method can be used if you
233      * are using the default.
234      *
235      * @param cipherKey the symmetric cipher key to use for both encryption and decryption.
236      */
237     public void setCipherKey(byte[] cipherKey) {
238         //Since this method should only be used in symmetric ciphers
239         //(where the enc and dec keys are the same), set it on both:
240         setEncryptionCipherKey(cipherKey);
241         setDecryptionCipherKey(cipherKey);
242     }
243 
244     /**
245      * Forgets (removes) any remembered identity data for the specified {@link Subject} instance.
246      *
247      * @param subject the subject instance for which identity data should be forgotten from the underlying persistence
248      *                mechanism.
249      */
250     protected abstract void forgetIdentity(Subject subject);
251 
252     /**
253      * Determines whether or not remember me services should be performed for the specified token.  This method returns
254      * {@code true} iff:
255      * <ol>
256      * <li>The token is not {@code null} and</li>
257      * <li>The token is an {@code instanceof} {@link RememberMeAuthenticationToken} and</li>
258      * <li>{@code token}.{@link org.apache.shiro.authc.RememberMeAuthenticationToken#isRememberMe() isRememberMe()} is
259      * {@code true}</li>
260      * </ol>
261      *
262      * @param token the authentication token submitted during the successful authentication attempt.
263      * @return true if remember me services should be performed as a result of the successful authentication attempt.
264      */
265     protected boolean isRememberMe(AuthenticationToken token) {
266         return token != null && (token instanceof RememberMeAuthenticationToken) &&
267                 ((RememberMeAuthenticationToken) token).isRememberMe();
268     }
269 
270     /**
271      * Reacts to the successful login attempt by first always {@link #forgetIdentity(Subject) forgetting} any previously
272      * stored identity.  Then if the {@code token}
273      * {@link #isRememberMe(org.apache.shiro.authc.AuthenticationToken) is a RememberMe} token, the associated identity
274      * will be {@link #rememberIdentity(org.apache.shiro.subject.Subject, org.apache.shiro.authc.AuthenticationToken, org.apache.shiro.authc.AuthenticationInfo) remembered}
275      * for later retrieval during a new user session.
276      *
277      * @param subject the subject for which the principals are being remembered.
278      * @param token   the token that resulted in a successful authentication attempt.
279      * @param info    the authentication info resulting from the successful authentication attempt.
280      */
281     public void onSuccessfulLogin(Subject subject, AuthenticationToken token, AuthenticationInfo info) {
282         //always clear any previous identity:
283         forgetIdentity(subject);
284 
285         //now save the new identity:
286         if (isRememberMe(token)) {
287             rememberIdentity(subject, token, info);
288         } else {
289             if (log.isDebugEnabled()) {
290                 log.debug("AuthenticationToken did not indicate RememberMe is requested.  " +
291                         "RememberMe functionality will not be executed for corresponding account.");
292             }
293         }
294     }
295 
296     /**
297      * Remembers a subject-unique identity for retrieval later.  This implementation first
298      * {@link #getIdentityToRemember resolves} the exact
299      * {@link PrincipalCollection principals} to remember.  It then remembers the principals by calling
300      * {@link #rememberIdentity(org.apache.shiro.subject.Subject, org.apache.shiro.subject.PrincipalCollection)}.
301      * <p/>
302      * This implementation ignores the {@link AuthenticationToken} argument, but it is available to subclasses if
303      * necessary for custom logic.
304      *
305      * @param subject   the subject for which the principals are being remembered.
306      * @param token     the token that resulted in a successful authentication attempt.
307      * @param authcInfo the authentication info resulting from the successful authentication attempt.
308      */
309     public void rememberIdentity(Subject subject, AuthenticationToken token, AuthenticationInfo authcInfo) {
310         PrincipalCollection principals = getIdentityToRemember(subject, authcInfo);
311         rememberIdentity(subject, principals);
312     }
313 
314     /**
315      * Returns {@code info}.{@link org.apache.shiro.authc.AuthenticationInfo#getPrincipals() getPrincipals()} and
316      * ignores the {@link Subject} argument.
317      *
318      * @param subject the subject for which the principals are being remembered.
319      * @param info    the authentication info resulting from the successful authentication attempt.
320      * @return the {@code PrincipalCollection} to remember.
321      */
322     protected PrincipalCollection getIdentityToRemember(Subject subject, AuthenticationInfo info) {
323         return info.getPrincipals();
324     }
325 
326     /**
327      * Remembers the specified account principals by first
328      * {@link #convertPrincipalsToBytes(org.apache.shiro.subject.PrincipalCollection) converting} them to a byte
329      * array and then {@link #rememberSerializedIdentity(org.apache.shiro.subject.Subject, byte[]) remembers} that
330      * byte array.
331      *
332      * @param subject           the subject for which the principals are being remembered.
333      * @param accountPrincipals the principals to remember for retrieval later.
334      */
335     protected void rememberIdentity(Subject subject, PrincipalCollection accountPrincipals) {
336         byte[] bytes = convertPrincipalsToBytes(accountPrincipals);
337         rememberSerializedIdentity(subject, bytes);
338     }
339 
340     /**
341      * Converts the given principal collection the byte array that will be persisted to be 'remembered' later.
342      * <p/>
343      * This implementation first {@link #serialize(org.apache.shiro.subject.PrincipalCollection) serializes} the
344      * principals to a byte array and then {@link #encrypt(byte[]) encrypts} that byte array.
345      *
346      * @param principals the {@code PrincipalCollection} to convert to a byte array
347      * @return the representative byte array to be persisted for remember me functionality.
348      */
349     protected byte[] convertPrincipalsToBytes(PrincipalCollection principals) {
350         byte[] bytes = serialize(principals);
351         if (getCipherService() != null) {
352             bytes = encrypt(bytes);
353         }
354         return bytes;
355     }
356 
357     /**
358      * Persists the identity bytes to a persistent store for retrieval later via the
359      * {@link #getRememberedSerializedIdentity(SubjectContext)} method.
360      *
361      * @param subject    the Subject for which the identity is being serialized.
362      * @param serialized the serialized bytes to be persisted.
363      */
364     protected abstract void rememberSerializedIdentity(Subject subject, byte[] serialized);
365 
366     /**
367      * Implements the interface method by first {@link #getRememberedSerializedIdentity(SubjectContext) acquiring}
368      * the remembered serialized byte array.  Then it {@link #convertBytesToPrincipals(byte[], SubjectContext) converts}
369      * them and returns the re-constituted {@link PrincipalCollection}.  If no remembered principals could be
370      * obtained, {@code null} is returned.
371      * <p/>
372      * If any exceptions are thrown, the {@link #onRememberedPrincipalFailure(RuntimeException, SubjectContext)} method
373      * is called to allow any necessary post-processing (such as immediately removing any previously remembered
374      * values for safety).
375      *
376      * @param subjectContext the contextual data, usually provided by a {@link Subject.Builder} implementation, that
377      *                       is being used to construct a {@link Subject} instance.
378      * @return the remembered principals or {@code null} if none could be acquired.
379      */
380     public PrincipalCollection getRememberedPrincipals(SubjectContext subjectContext) {
381         PrincipalCollection principals = null;
382         try {
383             byte[] bytes = getRememberedSerializedIdentity(subjectContext);
384             //SHIRO-138 - only call convertBytesToPrincipals if bytes exist:
385             if (bytes != null && bytes.length > 0) {
386                 principals = convertBytesToPrincipals(bytes, subjectContext);
387             }
388         } catch (RuntimeException re) {
389             principals = onRememberedPrincipalFailure(re, subjectContext);
390         }
391 
392         return principals;
393     }
394 
395     /**
396      * Based on the given subject context data, retrieves the previously persisted serialized identity, or
397      * {@code null} if there is no available data.  The context map is usually populated by a {@link Subject.Builder}
398      * implementation.  See the {@link SubjectFactory} class constants for Shiro's known map keys.
399      *
400      * @param subjectContext the contextual data, usually provided by a {@link Subject.Builder} implementation, that
401      *                       is being used to construct a {@link Subject} instance.  To be used to assist with data
402      *                       lookup.
403      * @return the previously persisted serialized identity, or {@code null} if there is no available data for the
404      *         Subject.
405      */
406     protected abstract byte[] getRememberedSerializedIdentity(SubjectContext subjectContext);
407 
408     /**
409      * If a {@link #getCipherService() cipherService} is available, it will be used to first decrypt the byte array.
410      * Then the bytes are then {@link #deserialize(byte[]) deserialized} and then returned.
411      *
412      * @param bytes          the bytes to decrypt if necessary and then deserialize.
413      * @param subjectContext the contextual data, usually provided by a {@link Subject.Builder} implementation, that
414      *                       is being used to construct a {@link Subject} instance.
415      * @return the de-serialized and possibly decrypted principals
416      */
417     protected PrincipalCollection convertBytesToPrincipals(byte[] bytes, SubjectContext subjectContext) {
418         if (getCipherService() != null) {
419             bytes = decrypt(bytes);
420         }
421         return deserialize(bytes);
422     }
423 
424     /**
425      * Called when an exception is thrown while trying to retrieve principals.  The default implementation logs a
426      * warning message and forgets ('unremembers') the problem identity by calling
427      * {@link #forgetIdentity(SubjectContext) forgetIdentity(context)} and then immediately re-throws the
428      * exception to allow the calling component to react accordingly.
429      * <p/>
430      * This method implementation never returns an
431      * object - it always rethrows, but can be overridden by subclasses for custom handling behavior.
432      * <p/>
433      * This most commonly would be called when an encryption key is updated and old principals are retrieved that have
434      * been encrypted with the previous key.
435      *
436      * @param e       the exception that was thrown.
437      * @param context the contextual data, usually provided by a {@link Subject.Builder} implementation, that
438      *                is being used to construct a {@link Subject} instance.
439      * @return nothing - the original {@code RuntimeException} is propagated in all cases.
440      */
441     protected PrincipalCollection onRememberedPrincipalFailure(RuntimeException e, SubjectContext context) {
442 
443         if (log.isWarnEnabled()) {
444             String message = "There was a failure while trying to retrieve remembered principals.  This could be due to a " +
445                     "configuration problem or corrupted principals.  This could also be due to a recently " +
446                     "changed encryption key, if you are using a shiro.ini file, this property would be " +
447                     "'securityManager.rememberMeManager.cipherKey' see: http://shiro.apache.org/web.html#Web-RememberMeServices. " +
448                     "The remembered identity will be forgotten and not used for this request.";
449             log.warn(message);
450         }
451         forgetIdentity(context);
452         //propagate - security manager implementation will handle and warn appropriately
453         throw e;
454     }
455 
456     /**
457      * Encrypts the byte array by using the configured {@link #getCipherService() cipherService}.
458      *
459      * @param serialized the serialized object byte array to be encrypted
460      * @return an encrypted byte array returned by the configured {@link #getCipherService () cipher}.
461      */
462     protected byte[] encrypt(byte[] serialized) {
463         byte[] value = serialized;
464         CipherService cipherService = getCipherService();
465         if (cipherService != null) {
466             ByteSource byteSource = cipherService.encrypt(serialized, getEncryptionCipherKey());
467             value = byteSource.getBytes();
468         }
469         return value;
470     }
471 
472     /**
473      * Decrypts the byte array using the configured {@link #getCipherService() cipherService}.
474      *
475      * @param encrypted the encrypted byte array to decrypt
476      * @return the decrypted byte array returned by the configured {@link #getCipherService () cipher}.
477      */
478     protected byte[] decrypt(byte[] encrypted) {
479         byte[] serialized = encrypted;
480         CipherService cipherService = getCipherService();
481         if (cipherService != null) {
482             ByteSource byteSource = cipherService.decrypt(encrypted, getDecryptionCipherKey());
483             serialized = byteSource.getBytes();
484         }
485         return serialized;
486     }
487 
488     /**
489      * Serializes the given {@code principals} by serializing them to a byte array by using the
490      * {@link #getSerializer() serializer}'s {@link Serializer#serialize(Object) serialize} method.
491      *
492      * @param principals the principal collection to serialize to a byte array
493      * @return the serialized principal collection in the form of a byte array
494      */
495     protected byte[] serialize(PrincipalCollection principals) {
496         return getSerializer().serialize(principals);
497     }
498 
499     /**
500      * De-serializes the given byte array by using the {@link #getSerializer() serializer}'s
501      * {@link Serializer#deserialize deserialize} method.
502      *
503      * @param serializedIdentity the previously serialized {@code PrincipalCollection} as a byte array
504      * @return the de-serialized (reconstituted) {@code PrincipalCollection}
505      */
506     protected PrincipalCollection deserialize(byte[] serializedIdentity) {
507         return getSerializer().deserialize(serializedIdentity);
508     }
509 
510     /**
511      * Reacts to a failed login by immediately {@link #forgetIdentity(org.apache.shiro.subject.Subject) forgetting} any
512      * previously remembered identity.  This is an additional security feature to prevent any remenant identity data
513      * from being retained in case the authentication attempt is not being executed by the expected user.
514      *
515      * @param subject the subject which executed the failed login attempt
516      * @param token   the authentication token resulting in a failed login attempt - ignored by this implementation
517      * @param ae      the exception thrown as a result of the failed login attempt - ignored by this implementation
518      */
519     public void onFailedLogin(Subject subject, AuthenticationToken token, AuthenticationException ae) {
520         forgetIdentity(subject);
521     }
522 
523     /**
524      * Reacts to a subject logging out of the application and immediately
525      * {@link #forgetIdentity(org.apache.shiro.subject.Subject) forgets} any previously stored identity and returns.
526      *
527      * @param subject the subject logging out.
528      */
529     public void onLogout(Subject subject) {
530         forgetIdentity(subject);
531     }
532 }