1 /*
2 * Copyright (c) 1996, 2013, 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
27 package sun.security.ssl;
28
29 import java.io.ByteArrayInputStream;
30 import java.io.IOException;
31 import java.util.Hashtable;
32 import java.util.Arrays;
33
34 import java.security.*;
35 import javax.crypto.*;
36 import javax.crypto.spec.IvParameterSpec;
37 import javax.crypto.spec.GCMParameterSpec;
38
39 import java.nio.*;
40
41 import sun.security.ssl.CipherSuite.*;
42 import static sun.security.ssl.CipherSuite.*;
43 import static sun.security.ssl.CipherSuite.CipherType.*;
44
45 import sun.misc.HexDumpEncoder;
46
47
48 /**
49 * This class handles bulk data enciphering/deciphering for each SSLv3
50 * message. This provides data confidentiality. Stream ciphers (such
51 * as RC4) don't need to do padding; block ciphers (e.g. DES) need it.
52 *
53 * Individual instances are obtained by calling the static method
54 * newCipherBox(), which should only be invoked by BulkCipher.newCipher().
55 *
56 * In RFC 2246, with bock ciphers in CBC mode, the Initialization
57 * Vector (IV) for the first record is generated with the other keys
58 * and secrets when the security parameters are set. The IV for
59 * subsequent records is the last ciphertext block from the previous
60 * record.
61 *
62 * In RFC 4346, the implicit Initialization Vector (IV) is replaced
63 * with an explicit IV to protect against CBC attacks. RFC 4346
64 * recommends two algorithms used to generated the per-record IV.
65 * The implementation uses the algorithm (2)(b), as described at
66 * section 6.2.3.2 of RFC 4346.
67 *
68 * The usage of IV in CBC block cipher can be illustrated in
69 * the following diagrams.
70 *
71 * (random)
72 * R P1 IV C1
73 * | | | |
74 * SIV---+ |-----+ |-... |----- |------
75 * | | | | | | | |
76 * +----+ | +----+ | +----+ | +----+ |
77 * | Ek | | + Ek + | | Dk | | | Dk | |
78 * +----+ | +----+ | +----+ | +----+ |
79 * | | | | | | | |
80 * |----| |----| SIV--+ |----| |-...
81 * | | | |
82 * IV C1 R P1
83 * (discard)
84 *
85 * CBC Encryption CBC Decryption
86 *
87 * NOTE that any ciphering involved in key exchange (e.g. with RSA) is
88 * handled separately.
89 *
90 * @author David Brownell
91 * @author Andreas Sterbenz
92 */
93 final class CipherBox {
94
95 // A CipherBox that implements the identity operation
96 final static CipherBox NULL = new CipherBox();
97
98 /* Class and subclass dynamic debugging support */
99 private static final Debug debug = Debug.getInstance("ssl");
100
101 // the protocol version this cipher conforms to
102 private final ProtocolVersion protocolVersion;
103
104 // cipher object
105 private final Cipher cipher;
106
107 /**
108 * secure random
109 */
110 private SecureRandom random;
111
112 /**
113 * fixed IV, the implicit nonce of AEAD cipher suite, only apply to
114 * AEAD cipher suites
115 */
116 private final byte[] fixedIv;
117
118 /**
119 * the key, reserved only for AEAD cipher initialization
120 */
121 private final Key key;
122
123 /**
124 * the operation mode, reserved for AEAD cipher initialization
125 */
126 private final int mode;
127
128 /**
129 * the authentication tag size, only apply to AEAD cipher suites
130 */
131 private final int tagSize;
132
133 /**
134 * the record IV length, only apply to AEAD cipher suites
135 */
136 private final int recordIvSize;
137
138 /**
139 * cipher type
140 */
141 private final CipherType cipherType;
142
143 /**
144 * Fixed masks of various block size, as the initial decryption IVs
145 * for TLS 1.1 or later.
146 *
147 * For performance, we do not use random IVs. As the initial decryption
148 * IVs will be discarded by TLS decryption processes, so the fixed masks
149 * do not hurt cryptographic strength.
150 */
151 private static Hashtable<Integer, IvParameterSpec> masks;
152
153 /**
154 * NULL cipherbox. Identity operation, no encryption.
155 */
156 private CipherBox() {
157 this.protocolVersion = ProtocolVersion.DEFAULT;
158 this.cipher = null;
159 this.cipherType = STREAM_CIPHER;
160 this.fixedIv = new byte[0];
161 this.key = null;
162 this.mode = Cipher.ENCRYPT_MODE; // choose at random
163 this.random = null;
164 this.tagSize = 0;
165 this.recordIvSize = 0;
166 }
167
168 /**
169 * Construct a new CipherBox using the cipher transformation.
170 *
171 * @exception NoSuchAlgorithmException if no appropriate JCE Cipher
172 * implementation could be found.
173 */
174 private CipherBox(ProtocolVersion protocolVersion, BulkCipher bulkCipher,
175 SecretKey key, IvParameterSpec iv, SecureRandom random,
176 boolean encrypt) throws NoSuchAlgorithmException {
177 try {
178 this.protocolVersion = protocolVersion;
179 this.cipher = JsseJce.getCipher(bulkCipher.transformation);
180 this.mode = encrypt ? Cipher.ENCRYPT_MODE : Cipher.DECRYPT_MODE;
181
182 if (random == null) {
183 random = JsseJce.getSecureRandom();
184 }
185 this.random = random;
186 this.cipherType = bulkCipher.cipherType;
187
188 /*
189 * RFC 4346 recommends two algorithms used to generated the
190 * per-record IV. The implementation uses the algorithm (2)(b),
191 * as described at section 6.2.3.2 of RFC 4346.
192 *
193 * As we don't care about the initial IV value for TLS 1.1 or
194 * later, so if the "iv" parameter is null, we use the default
195 * value generated by Cipher.init() for encryption, and a fixed
196 * mask for decryption.
197 */
198 if (iv == null && bulkCipher.ivSize != 0 &&
199 mode == Cipher.DECRYPT_MODE &&
200 protocolVersion.v >= ProtocolVersion.TLS11.v) {
201 iv = getFixedMask(bulkCipher.ivSize);
202 }
203
204 if (cipherType == AEAD_CIPHER) {
205 // AEAD must completely initialize the cipher for each packet,
206 // and so we save initialization parameters for packet
207 // processing time.
208
209 // Set the tag size for AEAD cipher
210 tagSize = bulkCipher.tagSize;
211
212 // Reserve the key for AEAD cipher initialization
213 this.key = key;
214
215 fixedIv = iv.getIV();
216 if (fixedIv == null ||
217 fixedIv.length != bulkCipher.fixedIvSize) {
218 throw new RuntimeException("Improper fixed IV for AEAD");
219 }
220
221 // Set the record IV length for AEAD cipher
222 recordIvSize = bulkCipher.ivSize - bulkCipher.fixedIvSize;
223
224 // DON'T initialize the cipher for AEAD!
225 } else {
226 // CBC only requires one initialization during its lifetime
227 // (future packets/IVs set the proper CBC state), so we can
228 // initialize now.
229
230 // Zeroize the variables that only apply to AEAD cipher
231 this.tagSize = 0;
232 this.fixedIv = new byte[0];
233 this.recordIvSize = 0;
234 this.key = null;
235
236 // Initialize the cipher
237 cipher.init(mode, key, iv, random);
238 }
239 } catch (NoSuchAlgorithmException e) {
240 throw e;
241 } catch (Exception e) {
242 throw new NoSuchAlgorithmException
243 ("Could not create cipher " + bulkCipher, e);
244 } catch (ExceptionInInitializerError e) {
245 throw new NoSuchAlgorithmException
246 ("Could not create cipher " + bulkCipher, e);
247 }
248 }
249
250 /*
251 * Factory method to obtain a new CipherBox object.
252 */
253 static CipherBox newCipherBox(ProtocolVersion version, BulkCipher cipher,
254 SecretKey key, IvParameterSpec iv, SecureRandom random,
255 boolean encrypt) throws NoSuchAlgorithmException {
256 if (cipher.allowed == false) {
257 throw new NoSuchAlgorithmException("Unsupported cipher " + cipher);
258 }
259
260 if (cipher == B_NULL) {
261 return NULL;
262 } else {
263 return new CipherBox(version, cipher, key, iv, random, encrypt);
264 }
265 }
266
267 /*
268 * Get a fixed mask, as the initial decryption IVs for TLS 1.1 or later.
269 */
270 private static IvParameterSpec getFixedMask(int ivSize) {
271 if (masks == null) {
272 masks = new Hashtable<Integer, IvParameterSpec>(5);
273 }
274
275 IvParameterSpec iv = masks.get(ivSize);
276 if (iv == null) {
277 iv = new IvParameterSpec(new byte[ivSize]);
278 masks.put(ivSize, iv);
279 }
280
281 return iv;
282 }
283
284 /*
285 * Encrypts a block of data, returning the size of the
286 * resulting block.
287 */
288 int encrypt(byte[] buf, int offset, int len) {
289 if (cipher == null) {
290 return len;
291 }
292
293 try {
294 int blockSize = cipher.getBlockSize();
295 if (cipherType == BLOCK_CIPHER) {
296 len = addPadding(buf, offset, len, blockSize);
297 }
298
299 if (debug != null && Debug.isOn("plaintext")) {
300 try {
301 HexDumpEncoder hd = new HexDumpEncoder();
302
303 System.out.println(
304 "Padded plaintext before ENCRYPTION: len = "
305 + len);
306 hd.encodeBuffer(
307 new ByteArrayInputStream(buf, offset, len),
308 System.out);
309 } catch (IOException e) { }
310 }
311
312
313 if (cipherType == AEAD_CIPHER) {
314 try {
315 return cipher.doFinal(buf, offset, len, buf, offset);
316 } catch (IllegalBlockSizeException | BadPaddingException ibe) {
317 // unlikely to happen
318 throw new RuntimeException(
319 "Cipher error in AEAD mode in JCE provider " +
320 cipher.getProvider().getName(), ibe);
321 }
322 } else {
323 int newLen = cipher.update(buf, offset, len, buf, offset);
324 if (newLen != len) {
325 // catch BouncyCastle buffering error
326 throw new RuntimeException("Cipher buffering error " +
327 "in JCE provider " + cipher.getProvider().getName());
328 }
329 return newLen;
330 }
331 } catch (ShortBufferException e) {
332 // unlikely to happen, we should have enough buffer space here
333 throw new ArrayIndexOutOfBoundsException(e.toString());
334 }
335 }
336
337 /*
338 * Encrypts a ByteBuffer block of data, returning the size of the
339 * resulting block.
340 *
341 * The byte buffers position and limit initially define the amount
342 * to encrypt. On return, the position and limit are
343 * set to last position padded/encrypted. The limit may have changed
344 * because of the added padding bytes.
345 */
346 int encrypt(ByteBuffer bb, int outLimit) {
347
348 int len = bb.remaining();
349
350 if (cipher == null) {
351 bb.position(bb.limit());
352 return len;
353 }
354
355 int pos = bb.position();
356
357 int blockSize = cipher.getBlockSize();
358 if (cipherType == BLOCK_CIPHER) {
359 // addPadding adjusts pos/limit
360 len = addPadding(bb, blockSize);
361 bb.position(pos);
362 }
363
364 if (debug != null && Debug.isOn("plaintext")) {
365 try {
366 HexDumpEncoder hd = new HexDumpEncoder();
367
368 System.out.println(
369 "Padded plaintext before ENCRYPTION: len = "
370 + len);
371 hd.encodeBuffer(bb.duplicate(), System.out);
372
373 } catch (IOException e) { }
374 }
375
376 /*
377 * Encrypt "in-place". This does not add its own padding.
378 */
379 ByteBuffer dup = bb.duplicate();
380 if (cipherType == AEAD_CIPHER) {
381 try {
382 int outputSize = cipher.getOutputSize(dup.remaining());
383 if (outputSize > bb.remaining()) {
384 // need to expand the limit of the output buffer for
385 // the authentication tag.
386 //
387 // DON'T worry about the buffer's capacity, we have
388 // reserved space for the authentication tag.
389 if (outLimit < pos + outputSize) {
390 // unlikely to happen
391 throw new ShortBufferException(
392 "need more space in output buffer");
393 }
394 bb.limit(pos + outputSize);
395 }
396 int newLen = cipher.doFinal(dup, bb);
397 if (newLen != outputSize) {
398 throw new RuntimeException(
399 "Cipher buffering error in JCE provider " +
400 cipher.getProvider().getName());
401 }
402 return newLen;
403 } catch (IllegalBlockSizeException |
404 BadPaddingException | ShortBufferException ibse) {
405 // unlikely to happen
406 throw new RuntimeException(
407 "Cipher error in AEAD mode in JCE provider " +
408 cipher.getProvider().getName(), ibse);
409 }
410 } else {
411 int newLen;
412 try {
413 newLen = cipher.update(dup, bb);
414 } catch (ShortBufferException sbe) {
415 // unlikely to happen
416 throw new RuntimeException("Cipher buffering error " +
417 "in JCE provider " + cipher.getProvider().getName());
418 }
419
420 if (bb.position() != dup.position()) {
421 throw new RuntimeException("bytebuffer padding error");
422 }
423
424 if (newLen != len) {
425 // catch BouncyCastle buffering error
426 throw new RuntimeException("Cipher buffering error " +
427 "in JCE provider " + cipher.getProvider().getName());
428 }
429 return newLen;
430 }
431 }
432
433
434 /*
435 * Decrypts a block of data, returning the size of the
436 * resulting block if padding was required.
437 *
438 * For SSLv3 and TLSv1.0, with block ciphers in CBC mode the
439 * Initialization Vector (IV) for the first record is generated by
440 * the handshake protocol, the IV for subsequent records is the
441 * last ciphertext block from the previous record.
442 *
443 * From TLSv1.1, the implicit IV is replaced with an explicit IV to
444 * protect against CBC attacks.
445 *
446 * Differentiating between bad_record_mac and decryption_failed alerts
447 * may permit certain attacks against CBC mode. It is preferable to
448 * uniformly use the bad_record_mac alert to hide the specific type of
449 * the error.
450 */
451 int decrypt(byte[] buf, int offset, int len,
452 int tagLen) throws BadPaddingException {
453 if (cipher == null) {
454 return len;
455 }
456
457 try {
458 int newLen;
459 if (cipherType == AEAD_CIPHER) {
460 try {
461 newLen = cipher.doFinal(buf, offset, len, buf, offset);
462 } catch (IllegalBlockSizeException ibse) {
463 // unlikely to happen
464 throw new RuntimeException(
465 "Cipher error in AEAD mode in JCE provider " +
466 cipher.getProvider().getName(), ibse);
467 }
468 } else {
469 newLen = cipher.update(buf, offset, len, buf, offset);
470 if (newLen != len) {
471 // catch BouncyCastle buffering error
472 throw new RuntimeException("Cipher buffering error " +
473 "in JCE provider " + cipher.getProvider().getName());
474 }
475 }
476 if (debug != null && Debug.isOn("plaintext")) {
477 try {
478 HexDumpEncoder hd = new HexDumpEncoder();
479
480 System.out.println(
481 "Padded plaintext after DECRYPTION: len = "
482 + newLen);
483 hd.encodeBuffer(
484 new ByteArrayInputStream(buf, offset, newLen),
485 System.out);
486 } catch (IOException e) { }
487 }
488
489 if (cipherType == BLOCK_CIPHER) {
490 int blockSize = cipher.getBlockSize();
491 newLen = removePadding(
492 buf, offset, newLen, tagLen, blockSize, protocolVersion);
493
494 if (protocolVersion.v >= ProtocolVersion.TLS11.v) {
495 if (newLen < blockSize) {
496 throw new BadPaddingException("invalid explicit IV");
497 }
498 }
499 }
500 return newLen;
501 } catch (ShortBufferException e) {
502 // unlikely to happen, we should have enough buffer space here
503 throw new ArrayIndexOutOfBoundsException(e.toString());
504 }
505 }
506
507
508 /*
509 * Decrypts a block of data, returning the size of the
510 * resulting block if padding was required. position and limit
511 * point to the end of the decrypted/depadded data. The initial
512 * limit and new limit may be different, given we may
513 * have stripped off some padding bytes.
514 *
515 * @see decrypt(byte[], int, int)
516 */
517 int decrypt(ByteBuffer bb, int tagLen) throws BadPaddingException {
518
519 int len = bb.remaining();
520
521 if (cipher == null) {
522 bb.position(bb.limit());
523 return len;
524 }
525
526 try {
527 /*
528 * Decrypt "in-place".
529 */
530 int pos = bb.position();
531 ByteBuffer dup = bb.duplicate();
532 int newLen;
533 if (cipherType == AEAD_CIPHER) {
534 try {
535 newLen = cipher.doFinal(dup, bb);
536 } catch (IllegalBlockSizeException ibse) {
537 // unlikely to happen
538 throw new RuntimeException(
539 "Cipher error in AEAD mode \"" + ibse.getMessage() +
540 " \"in JCE provider " + cipher.getProvider().getName());
541 }
542 } else {
543 newLen = cipher.update(dup, bb);
544 if (newLen != len) {
545 // catch BouncyCastle buffering error
546 throw new RuntimeException("Cipher buffering error " +
547 "in JCE provider " + cipher.getProvider().getName());
548 }
549 }
550
551 // reset the limit to the end of the decryted data
552 bb.limit(pos + newLen);
553
554 if (debug != null && Debug.isOn("plaintext")) {
555 try {
556 HexDumpEncoder hd = new HexDumpEncoder();
557
558 System.out.println(
559 "Padded plaintext after DECRYPTION: len = "
560 + newLen);
561
562 hd.encodeBuffer(
563 bb.duplicate().position(pos), System.out);
564 } catch (IOException e) { }
565 }
566
567 /*
568 * Remove the block padding.
569 */
570 if (cipherType == BLOCK_CIPHER) {
571 int blockSize = cipher.getBlockSize();
572 bb.position(pos);
573 newLen = removePadding(bb, tagLen, blockSize, protocolVersion);
574
575 // check the explicit IV of TLS v1.1 or later
576 if (protocolVersion.v >= ProtocolVersion.TLS11.v) {
577 if (newLen < blockSize) {
578 throw new BadPaddingException("invalid explicit IV");
579 }
580
581 // reset the position to the end of the decrypted data
582 bb.position(bb.limit());
583 }
584 }
585 return newLen;
586 } catch (ShortBufferException e) {
587 // unlikely to happen, we should have enough buffer space here
588 throw new ArrayIndexOutOfBoundsException(e.toString());
589 }
590 }
591
592 private static int addPadding(byte[] buf, int offset, int len,
593 int blockSize) {
594 int newlen = len + 1;
595 byte pad;
596 int i;
597
598 if ((newlen % blockSize) != 0) {
599 newlen += blockSize - 1;
600 newlen -= newlen % blockSize;
601 }
602 pad = (byte) (newlen - len);
603
604 if (buf.length < (newlen + offset)) {
605 throw new IllegalArgumentException("no space to pad buffer");
606 }
607
608 /*
609 * TLS version of the padding works for both SSLv3 and TLSv1
610 */
611 for (i = 0, offset += len; i < pad; i++) {
612 buf [offset++] = (byte) (pad - 1);
613 }
614 return newlen;
615 }
616
617 /*
618 * Apply the padding to the buffer.
619 *
620 * Limit is advanced to the new buffer length.
621 * Position is equal to limit.
622 */
623 private static int addPadding(ByteBuffer bb, int blockSize) {
624
625 int len = bb.remaining();
626 int offset = bb.position();
627
628 int newlen = len + 1;
629 byte pad;
630 int i;
631
632 if ((newlen % blockSize) != 0) {
633 newlen += blockSize - 1;
634 newlen -= newlen % blockSize;
635 }
636 pad = (byte) (newlen - len);
637
638 /*
639 * Update the limit to what will be padded.
640 */
641 bb.limit(newlen + offset);
642
643 /*
644 * TLS version of the padding works for both SSLv3 and TLSv1
645 */
646 for (i = 0, offset += len; i < pad; i++) {
647 bb.put(offset++, (byte) (pad - 1));
648 }
649
650 bb.position(offset);
651 bb.limit(offset);
652
653 return newlen;
654 }
655
656 /*
657 * A constant-time check of the padding.
658 *
659 * NOTE that we are checking both the padding and the padLen bytes here.
660 *
661 * The caller MUST ensure that the len parameter is a positive number.
662 */
663 private static int[] checkPadding(
664 byte[] buf, int offset, int len, byte pad) {
665
666 if (len <= 0) {
667 throw new RuntimeException("padding len must be positive");
668 }
669
670 // An array of hits is used to prevent Hotspot optimization for
671 // the purpose of a constant-time check.
672 int[] results = {0, 0}; // {missed #, matched #}
673 for (int i = 0; i <= 256;) {
674 for (int j = 0; j < len && i <= 256; j++, i++) { // j <= i
675 if (buf[offset + j] != pad) {
676 results[0]++; // mismatched padding data
677 } else {
678 results[1]++; // matched padding data
679 }
680 }
681 }
682
683 return results;
684 }
685
686 /*
687 * A constant-time check of the padding.
688 *
689 * NOTE that we are checking both the padding and the padLen bytes here.
690 *
691 * The caller MUST ensure that the bb parameter has remaining.
692 */
693 private static int[] checkPadding(ByteBuffer bb, byte pad) {
694
695 if (!bb.hasRemaining()) {
696 throw new RuntimeException("hasRemaining() must be positive");
697 }
698
699 // An array of hits is used to prevent Hotspot optimization for
700 // the purpose of a constant-time check.
701 int[] results = {0, 0}; // {missed #, matched #}
702 bb.mark();
703 for (int i = 0; i <= 256; bb.reset()) {
704 for (; bb.hasRemaining() && i <= 256; i++) {
705 if (bb.get() != pad) {
706 results[0]++; // mismatched padding data
707 } else {
708 results[1]++; // matched padding data
709 }
710 }
711 }
712
713 return results;
714 }
715
716 /*
717 * Typical TLS padding format for a 64 bit block cipher is as follows:
718 * xx xx xx xx xx xx xx 00
719 * xx xx xx xx xx xx 01 01
720 * ...
721 * xx 06 06 06 06 06 06 06
722 * 07 07 07 07 07 07 07 07
723 * TLS also allows any amount of padding from 1 and 256 bytes as long
724 * as it makes the data a multiple of the block size
725 */
726 private static int removePadding(byte[] buf, int offset, int len,
727 int tagLen, int blockSize,
728 ProtocolVersion protocolVersion) throws BadPaddingException {
729
730 // last byte is length byte (i.e. actual padding length - 1)
731 int padOffset = offset + len - 1;
732 int padLen = buf[padOffset] & 0xFF;
733
734 int newLen = len - (padLen + 1);
735 if ((newLen - tagLen) < 0) {
736 // If the buffer is not long enough to contain the padding plus
737 // a MAC tag, do a dummy constant-time padding check.
738 //
739 // Note that it is a dummy check, so we won't care about what is
740 // the actual padding data.
741 checkPadding(buf, offset, len, (byte)(padLen & 0xFF));
742
743 throw new BadPaddingException("Invalid Padding length: " + padLen);
744 }
745
746 // The padding data should be filled with the padding length value.
747 int[] results = checkPadding(buf, offset + newLen,
748 padLen + 1, (byte)(padLen & 0xFF));
749 if (protocolVersion.v >= ProtocolVersion.TLS10.v) {
750 if (results[0] != 0) { // padding data has invalid bytes
751 throw new BadPaddingException("Invalid TLS padding data");
752 }
753 } else { // SSLv3
754 // SSLv3 requires 0 <= length byte < block size
755 // some implementations do 1 <= length byte <= block size,
756 // so accept that as well
757 // v3 does not require any particular value for the other bytes
758 if (padLen > blockSize) {
759 throw new BadPaddingException("Invalid SSLv3 padding");
760 }
761 }
762 return newLen;
763 }
764
765 /*
766 * Position/limit is equal the removed padding.
767 */
768 private static int removePadding(ByteBuffer bb,
769 int tagLen, int blockSize,
770 ProtocolVersion protocolVersion) throws BadPaddingException {
771
772 int len = bb.remaining();
773 int offset = bb.position();
774
775 // last byte is length byte (i.e. actual padding length - 1)
776 int padOffset = offset + len - 1;
777 int padLen = bb.get(padOffset) & 0xFF;
778
779 int newLen = len - (padLen + 1);
780 if ((newLen - tagLen) < 0) {
781 // If the buffer is not long enough to contain the padding plus
782 // a MAC tag, do a dummy constant-time padding check.
783 //
784 // Note that it is a dummy check, so we won't care about what is
785 // the actual padding data.
786 checkPadding(bb.duplicate(), (byte)(padLen & 0xFF));
787
788 throw new BadPaddingException("Invalid Padding length: " + padLen);
789 }
790
791 // The padding data should be filled with the padding length value.
792 int[] results = checkPadding(
793 bb.duplicate().position(offset + newLen),
794 (byte)(padLen & 0xFF));
795 if (protocolVersion.v >= ProtocolVersion.TLS10.v) {
796 if (results[0] != 0) { // padding data has invalid bytes
797 throw new BadPaddingException("Invalid TLS padding data");
798 }
799 } else { // SSLv3
800 // SSLv3 requires 0 <= length byte < block size
801 // some implementations do 1 <= length byte <= block size,
802 // so accept that as well
803 // v3 does not require any particular value for the other bytes
804 if (padLen > blockSize) {
805 throw new BadPaddingException("Invalid SSLv3 padding");
806 }
807 }
808
809 /*
810 * Reset buffer limit to remove padding.
811 */
812 bb.position(offset + newLen);
813 bb.limit(offset + newLen);
814
815 return newLen;
816 }
817
818 /*
819 * Dispose of any intermediate state in the underlying cipher.
820 * For PKCS11 ciphers, this will release any attached sessions, and
821 * thus make finalization faster.
822 */
823 void dispose() {
824 try {
825 if (cipher != null) {
826 // ignore return value.
827 cipher.doFinal();
828 }
829 } catch (Exception e) {
830 // swallow all types of exceptions.
831 }
832 }
833
834 /*
835 * Does the cipher use CBC mode?
836 *
837 * @return true if the cipher use CBC mode, false otherwise.
838 */
839 boolean isCBCMode() {
840 return cipherType == BLOCK_CIPHER;
841 }
842
843 /*
844 * Does the cipher use AEAD mode?
845 *
846 * @return true if the cipher use AEAD mode, false otherwise.
847 */
848 boolean isAEADMode() {
849 return cipherType == AEAD_CIPHER;
850 }
851
852 /*
853 * Is the cipher null?
854 *
855 * @return true if the cipher is null, false otherwise.
856 */
857 boolean isNullCipher() {
858 return cipher == null;
859 }
860
861 /*
862 * Gets the explicit nonce/IV size of the cipher.
863 *
864 * The returned value is the SecurityParameters.record_iv_length in
865 * RFC 4346/5246. It is the size of explicit IV for CBC mode, and the
866 * size of explicit nonce for AEAD mode.
867 *
868 * @return the explicit nonce size of the cipher.
869 */
870 int getExplicitNonceSize() {
871 switch (cipherType) {
872 case BLOCK_CIPHER:
873 // For block ciphers, the explicit IV length is of length
874 // SecurityParameters.record_iv_length, which is equal to
875 // the SecurityParameters.block_size.
876 if (protocolVersion.v >= ProtocolVersion.TLS11.v) {
877 return cipher.getBlockSize();
878 }
879 break;
880 case AEAD_CIPHER:
881 return recordIvSize;
882 // It is also the length of sequence number, which is
883 // used as the nonce_explicit for AEAD cipher suites.
884 }
885
886 return 0;
887 }
888
889 /*
890 * Applies the explicit nonce/IV to this cipher. This method is used to
891 * decrypt an SSL/TLS input record.
892 *
893 * The returned value is the SecurityParameters.record_iv_length in
894 * RFC 4346/5246. It is the size of explicit IV for CBC mode, and the
895 * size of explicit nonce for AEAD mode.
896 *
897 * @param authenticator the authenticator to get the additional
898 * authentication data
899 * @param contentType the content type of the input record
900 * @param bb the byte buffer to get the explicit nonce from
901 *
902 * @return the explicit nonce size of the cipher.
903 */
904 int applyExplicitNonce(Authenticator authenticator, byte contentType,
905 ByteBuffer bb) throws BadPaddingException {
906 switch (cipherType) {
907 case BLOCK_CIPHER:
908 // sanity check length of the ciphertext
909 int tagLen = (authenticator instanceof MAC) ?
910 ((MAC)authenticator).MAClen() : 0;
911 if (tagLen != 0) {
912 if (!sanityCheck(tagLen, bb.remaining())) {
913 throw new BadPaddingException(
914 "ciphertext sanity check failed");
915 }
916 }
917
918 // For block ciphers, the explicit IV length is of length
919 // SecurityParameters.record_iv_length, which is equal to
920 // the SecurityParameters.block_size.
921 if (protocolVersion.v >= ProtocolVersion.TLS11.v) {
922 return cipher.getBlockSize();
923 }
924 break;
925 case AEAD_CIPHER:
926 if (bb.remaining() < (recordIvSize + tagSize)) {
927 throw new BadPaddingException(
928 "invalid AEAD cipher fragment");
929 }
930
931 // initialize the AEAD cipher for the unique IV
932 byte[] iv = Arrays.copyOf(fixedIv,
933 fixedIv.length + recordIvSize);
934 bb.get(iv, fixedIv.length, recordIvSize);
935 bb.position(bb.position() - recordIvSize);
936 GCMParameterSpec spec = new GCMParameterSpec(tagSize * 8, iv);
937 try {
938 cipher.init(mode, key, spec, random);
939 } catch (InvalidKeyException |
940 InvalidAlgorithmParameterException ikae) {
941 // unlikely to happen
942 throw new RuntimeException(
943 "invalid key or spec in GCM mode", ikae);
944 }
945
946 // update the additional authentication data
947 byte[] aad = authenticator.acquireAuthenticationBytes(
948 contentType, bb.remaining() - recordIvSize - tagSize);
949 cipher.updateAAD(aad);
950
951 return recordIvSize;
952 // It is also the length of sequence number, which is
953 // used as the nonce_explicit for AEAD cipher suites.
954 }
955
956 return 0;
957 }
958
959 /*
960 * Applies the explicit nonce/IV to this cipher. This method is used to
961 * decrypt an SSL/TLS input record.
962 *
963 * The returned value is the SecurityParameters.record_iv_length in
964 * RFC 4346/5246. It is the size of explicit IV for CBC mode, and the
965 * size of explicit nonce for AEAD mode.
966 *
967 * @param authenticator the authenticator to get the additional
968 * authentication data
969 * @param contentType the content type of the input record
970 * @param buf the byte array to get the explicit nonce from
971 * @param offset the offset of the byte buffer
972 * @param cipheredLength the ciphered fragment length of the output
973 * record, it is the TLSCiphertext.length in RFC 4346/5246.
974 *
975 * @return the explicit nonce size of the cipher.
976 */
977 int applyExplicitNonce(Authenticator authenticator,
978 byte contentType, byte[] buf, int offset,
979 int cipheredLength) throws BadPaddingException {
980
981 ByteBuffer bb = ByteBuffer.wrap(buf, offset, cipheredLength);
982
983 return applyExplicitNonce(authenticator, contentType, bb);
984 }
985
986 /*
987 * Creates the explicit nonce/IV to this cipher. This method is used to
988 * encrypt an SSL/TLS output record.
989 *
990 * The size of the returned array is the SecurityParameters.record_iv_length
991 * in RFC 4346/5246. It is the size of explicit IV for CBC mode, and the
992 * size of explicit nonce for AEAD mode.
993 *
994 * @param authenticator the authenticator to get the additional
995 * authentication data
996 * @param contentType the content type of the input record
997 * @param fragmentLength the fragment length of the output record, it is
998 * the TLSCompressed.length in RFC 4346/5246.
999 *
1000 * @return the explicit nonce of the cipher.
1001 */
1002 byte[] createExplicitNonce(Authenticator authenticator,
1003 byte contentType, int fragmentLength) {
1004
1005 byte[] nonce = new byte[0];
1006 switch (cipherType) {
1007 case BLOCK_CIPHER:
1008 if (protocolVersion.v >= ProtocolVersion.TLS11.v) {
1009 // For block ciphers, the explicit IV length is of length
1010 // SecurityParameters.record_iv_length, which is equal to
1011 // the SecurityParameters.block_size.
1012 //
1013 // Generate a random number as the explicit IV parameter.
1014 nonce = new byte[cipher.getBlockSize()];
1015 random.nextBytes(nonce);
1016 }
1017 break;
1018 case AEAD_CIPHER:
1019 // To be unique and aware of overflow-wrap, sequence number
1020 // is used as the nonce_explicit of AEAD cipher suites.
1021 nonce = authenticator.sequenceNumber();
1022
1023 // initialize the AEAD cipher for the unique IV
1024 byte[] iv = Arrays.copyOf(fixedIv,
1025 fixedIv.length + nonce.length);
1026 System.arraycopy(nonce, 0, iv, fixedIv.length, nonce.length);
1027 GCMParameterSpec spec = new GCMParameterSpec(tagSize * 8, iv);
1028 try {
1029 cipher.init(mode, key, spec, random);
1030 } catch (InvalidKeyException |
1031 InvalidAlgorithmParameterException ikae) {
1032 // unlikely to happen
1033 throw new RuntimeException(
1034 "invalid key or spec in GCM mode", ikae);
1035 }
1036
1037 // update the additional authentication data
1038 byte[] aad = authenticator.acquireAuthenticationBytes(
1039 contentType, fragmentLength);
1040 cipher.updateAAD(aad);
1041 break;
1042 }
1043
1044 return nonce;
1045 }
1046
1047 /*
1048 * Is this cipher available?
1049 *
1050 * This method can only be called by CipherSuite.BulkCipher.isAvailable()
1051 * to test the availability of a cipher suites. Please DON'T use it in
1052 * other places, otherwise, the behavior may be unexpected because we may
1053 * initialize AEAD cipher improperly in the method.
1054 */
1055 Boolean isAvailable() {
1056 // We won't know whether a cipher for a particular key size is
1057 // available until the cipher is successfully initialized.
1058 //
1059 // We do not initialize AEAD cipher in the constructor. Need to
1060 // initialize the cipher to ensure that the AEAD mode for a
1061 // particular key size is supported.
1062 if (cipherType == AEAD_CIPHER) {
1063 try {
1064 Authenticator authenticator =
1065 new Authenticator(protocolVersion);
1066 byte[] nonce = authenticator.sequenceNumber();
1067 byte[] iv = Arrays.copyOf(fixedIv,
1068 fixedIv.length + nonce.length);
1069 System.arraycopy(nonce, 0, iv, fixedIv.length, nonce.length);
1070 GCMParameterSpec spec = new GCMParameterSpec(tagSize * 8, iv);
1071
1072 cipher.init(mode, key, spec, random);
1073 } catch (Exception e) {
1074 return Boolean.FALSE;
1075 }
1076 } // Otherwise, we have initialized the cipher in the constructor.
1077
1078 return Boolean.TRUE;
1079 }
1080
1081 /**
1082 * Sanity check the length of a fragment before decryption.
1083 *
1084 * In CBC mode, check that the fragment length is one or multiple times
1085 * of the block size of the cipher suite, and is at least one (one is the
1086 * smallest size of padding in CBC mode) bigger than the tag size of the
1087 * MAC algorithm except the explicit IV size for TLS 1.1 or later.
1088 *
1089 * In non-CBC mode, check that the fragment length is not less than the
1090 * tag size of the MAC algorithm.
1091 *
1092 * @return true if the length of a fragment matches above requirements
1093 */
1094 private boolean sanityCheck(int tagLen, int fragmentLen) {
1095 if (!isCBCMode()) {
1096 return fragmentLen >= tagLen;
1097 }
1098
1099 int blockSize = cipher.getBlockSize();
1100 if ((fragmentLen % blockSize) == 0) {
1101 int minimal = tagLen + 1;
1102 minimal = (minimal >= blockSize) ? minimal : blockSize;
1103 if (protocolVersion.v >= ProtocolVersion.TLS11.v) {
1104 minimal += blockSize; // plus the size of the explicit IV
1105 }
1106
1107 return (fragmentLen >= minimal);
1108 }
1109
1110 return false;
1111 }
1112
1113 }