1 /*
2 * NIST SP800-38C compliant CCM implementation
3 *
4 * Copyright The Mbed TLS Contributors
5 * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
6 */
7
8 /*
9 * Definition of CCM:
10 * http://csrc.nist.gov/publications/nistpubs/800-38C/SP800-38C_updated-July20_2007.pdf
11 * RFC 3610 "Counter with CBC-MAC (CCM)"
12 *
13 * Related:
14 * RFC 5116 "An Interface and Algorithms for Authenticated Encryption"
15 */
16
17 #include "common.h"
18
19 #if defined(MBEDTLS_CCM_C)
20
21 #include "mbedtls/ccm.h"
22 #include "mbedtls/platform_util.h"
23 #include "mbedtls/error.h"
24 #include "mbedtls/constant_time.h"
25
26 #if defined(MBEDTLS_BLOCK_CIPHER_C)
27 #include "block_cipher_internal.h"
28 #endif
29
30 #include <string.h>
31
32 #if defined(MBEDTLS_PLATFORM_C)
33 #include "mbedtls/platform.h"
34 #else
35 #if defined(MBEDTLS_SELF_TEST) && defined(MBEDTLS_AES_C)
36 #include <stdio.h>
37 #define mbedtls_printf printf
38 #endif /* MBEDTLS_SELF_TEST && MBEDTLS_AES_C */
39 #endif /* MBEDTLS_PLATFORM_C */
40
41 #if !defined(MBEDTLS_CCM_ALT)
42
43
44 /*
45 * Initialize context
46 */
mbedtls_ccm_init(mbedtls_ccm_context * ctx)47 void mbedtls_ccm_init(mbedtls_ccm_context *ctx)
48 {
49 memset(ctx, 0, sizeof(mbedtls_ccm_context));
50 }
51
mbedtls_ccm_setkey(mbedtls_ccm_context * ctx,mbedtls_cipher_id_t cipher,const unsigned char * key,unsigned int keybits)52 int mbedtls_ccm_setkey(mbedtls_ccm_context *ctx,
53 mbedtls_cipher_id_t cipher,
54 const unsigned char *key,
55 unsigned int keybits)
56 {
57 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
58
59 #if defined(MBEDTLS_BLOCK_CIPHER_C)
60 mbedtls_block_cipher_free(&ctx->block_cipher_ctx);
61
62 if ((ret = mbedtls_block_cipher_setup(&ctx->block_cipher_ctx, cipher)) != 0) {
63 return MBEDTLS_ERR_CCM_BAD_INPUT;
64 }
65
66 if ((ret = mbedtls_block_cipher_setkey(&ctx->block_cipher_ctx, key, keybits)) != 0) {
67 return MBEDTLS_ERR_CCM_BAD_INPUT;
68 }
69 #else
70 const mbedtls_cipher_info_t *cipher_info;
71
72 cipher_info = mbedtls_cipher_info_from_values(cipher, keybits,
73 MBEDTLS_MODE_ECB);
74 if (cipher_info == NULL) {
75 return MBEDTLS_ERR_CCM_BAD_INPUT;
76 }
77
78 if (mbedtls_cipher_info_get_block_size(cipher_info) != 16) {
79 return MBEDTLS_ERR_CCM_BAD_INPUT;
80 }
81
82 mbedtls_cipher_free(&ctx->cipher_ctx);
83
84 if ((ret = mbedtls_cipher_setup(&ctx->cipher_ctx, cipher_info)) != 0) {
85 return ret;
86 }
87
88 if ((ret = mbedtls_cipher_setkey(&ctx->cipher_ctx, key, keybits,
89 MBEDTLS_ENCRYPT)) != 0) {
90 return ret;
91 }
92 #endif
93
94 return ret;
95 }
96
97 /*
98 * Free context
99 */
mbedtls_ccm_free(mbedtls_ccm_context * ctx)100 void mbedtls_ccm_free(mbedtls_ccm_context *ctx)
101 {
102 if (ctx == NULL) {
103 return;
104 }
105 #if defined(MBEDTLS_BLOCK_CIPHER_C)
106 mbedtls_block_cipher_free(&ctx->block_cipher_ctx);
107 #else
108 mbedtls_cipher_free(&ctx->cipher_ctx);
109 #endif
110 mbedtls_platform_zeroize(ctx, sizeof(mbedtls_ccm_context));
111 }
112
113 #define CCM_STATE__CLEAR 0
114 #define CCM_STATE__STARTED (1 << 0)
115 #define CCM_STATE__LENGTHS_SET (1 << 1)
116 #define CCM_STATE__AUTH_DATA_STARTED (1 << 2)
117 #define CCM_STATE__AUTH_DATA_FINISHED (1 << 3)
118 #define CCM_STATE__ERROR (1 << 4)
119
120 /*
121 * Encrypt or decrypt a partial block with CTR
122 */
mbedtls_ccm_crypt(mbedtls_ccm_context * ctx,size_t offset,size_t use_len,const unsigned char * input,unsigned char * output)123 static int mbedtls_ccm_crypt(mbedtls_ccm_context *ctx,
124 size_t offset, size_t use_len,
125 const unsigned char *input,
126 unsigned char *output)
127 {
128 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
129 unsigned char tmp_buf[16] = { 0 };
130
131 #if defined(MBEDTLS_BLOCK_CIPHER_C)
132 ret = mbedtls_block_cipher_encrypt(&ctx->block_cipher_ctx, ctx->ctr, tmp_buf);
133 #else
134 size_t olen = 0;
135 ret = mbedtls_cipher_update(&ctx->cipher_ctx, ctx->ctr, 16, tmp_buf, &olen);
136 #endif
137 if (ret != 0) {
138 ctx->state |= CCM_STATE__ERROR;
139 mbedtls_platform_zeroize(tmp_buf, sizeof(tmp_buf));
140 return ret;
141 }
142
143 mbedtls_xor(output, input, tmp_buf + offset, use_len);
144
145 mbedtls_platform_zeroize(tmp_buf, sizeof(tmp_buf));
146 return ret;
147 }
148
mbedtls_ccm_clear_state(mbedtls_ccm_context * ctx)149 static void mbedtls_ccm_clear_state(mbedtls_ccm_context *ctx)
150 {
151 ctx->state = CCM_STATE__CLEAR;
152 memset(ctx->y, 0, 16);
153 memset(ctx->ctr, 0, 16);
154 }
155
ccm_calculate_first_block_if_ready(mbedtls_ccm_context * ctx)156 static int ccm_calculate_first_block_if_ready(mbedtls_ccm_context *ctx)
157 {
158 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
159 unsigned char i;
160 size_t len_left;
161 #if !defined(MBEDTLS_BLOCK_CIPHER_C)
162 size_t olen;
163 #endif
164
165 /* length calculation can be done only after both
166 * mbedtls_ccm_starts() and mbedtls_ccm_set_lengths() have been executed
167 */
168 if (!(ctx->state & CCM_STATE__STARTED) || !(ctx->state & CCM_STATE__LENGTHS_SET)) {
169 return 0;
170 }
171
172 /* CCM expects non-empty tag.
173 * CCM* allows empty tag. For CCM* without tag, the tag calculation is skipped.
174 */
175 if (ctx->tag_len == 0) {
176 if (ctx->mode == MBEDTLS_CCM_STAR_ENCRYPT || ctx->mode == MBEDTLS_CCM_STAR_DECRYPT) {
177 ctx->plaintext_len = 0;
178 return 0;
179 } else {
180 return MBEDTLS_ERR_CCM_BAD_INPUT;
181 }
182 }
183
184 /*
185 * First block:
186 * 0 .. 0 flags
187 * 1 .. iv_len nonce (aka iv) - set by: mbedtls_ccm_starts()
188 * iv_len+1 .. 15 length
189 *
190 * With flags as (bits):
191 * 7 0
192 * 6 add present?
193 * 5 .. 3 (t - 2) / 2
194 * 2 .. 0 q - 1
195 */
196 ctx->y[0] |= (ctx->add_len > 0) << 6;
197 ctx->y[0] |= ((ctx->tag_len - 2) / 2) << 3;
198 ctx->y[0] |= ctx->q - 1;
199
200 for (i = 0, len_left = ctx->plaintext_len; i < ctx->q; i++, len_left >>= 8) {
201 ctx->y[15-i] = MBEDTLS_BYTE_0(len_left);
202 }
203
204 if (len_left > 0) {
205 ctx->state |= CCM_STATE__ERROR;
206 return MBEDTLS_ERR_CCM_BAD_INPUT;
207 }
208
209 /* Start CBC-MAC with first block*/
210 #if defined(MBEDTLS_BLOCK_CIPHER_C)
211 ret = mbedtls_block_cipher_encrypt(&ctx->block_cipher_ctx, ctx->y, ctx->y);
212 #else
213 ret = mbedtls_cipher_update(&ctx->cipher_ctx, ctx->y, 16, ctx->y, &olen);
214 #endif
215 if (ret != 0) {
216 ctx->state |= CCM_STATE__ERROR;
217 return ret;
218 }
219
220 return 0;
221 }
222
mbedtls_ccm_starts(mbedtls_ccm_context * ctx,int mode,const unsigned char * iv,size_t iv_len)223 int mbedtls_ccm_starts(mbedtls_ccm_context *ctx,
224 int mode,
225 const unsigned char *iv,
226 size_t iv_len)
227 {
228 /* Also implies q is within bounds */
229 if (iv_len < 7 || iv_len > 13) {
230 return MBEDTLS_ERR_CCM_BAD_INPUT;
231 }
232
233 ctx->mode = mode;
234 ctx->q = 16 - 1 - (unsigned char) iv_len;
235
236 /*
237 * Prepare counter block for encryption:
238 * 0 .. 0 flags
239 * 1 .. iv_len nonce (aka iv)
240 * iv_len+1 .. 15 counter (initially 1)
241 *
242 * With flags as (bits):
243 * 7 .. 3 0
244 * 2 .. 0 q - 1
245 */
246 memset(ctx->ctr, 0, 16);
247 ctx->ctr[0] = ctx->q - 1;
248 memcpy(ctx->ctr + 1, iv, iv_len);
249 memset(ctx->ctr + 1 + iv_len, 0, ctx->q);
250 ctx->ctr[15] = 1;
251
252 /*
253 * See ccm_calculate_first_block_if_ready() for block layout description
254 */
255 memcpy(ctx->y + 1, iv, iv_len);
256
257 ctx->state |= CCM_STATE__STARTED;
258 return ccm_calculate_first_block_if_ready(ctx);
259 }
260
mbedtls_ccm_set_lengths(mbedtls_ccm_context * ctx,size_t total_ad_len,size_t plaintext_len,size_t tag_len)261 int mbedtls_ccm_set_lengths(mbedtls_ccm_context *ctx,
262 size_t total_ad_len,
263 size_t plaintext_len,
264 size_t tag_len)
265 {
266 /*
267 * Check length requirements: SP800-38C A.1
268 * Additional requirement: a < 2^16 - 2^8 to simplify the code.
269 * 'length' checked later (when writing it to the first block)
270 *
271 * Also, loosen the requirements to enable support for CCM* (IEEE 802.15.4).
272 */
273 if (tag_len == 2 || tag_len > 16 || tag_len % 2 != 0) {
274 return MBEDTLS_ERR_CCM_BAD_INPUT;
275 }
276
277 if (total_ad_len >= 0xFF00) {
278 return MBEDTLS_ERR_CCM_BAD_INPUT;
279 }
280
281 ctx->plaintext_len = plaintext_len;
282 ctx->add_len = total_ad_len;
283 ctx->tag_len = tag_len;
284 ctx->processed = 0;
285
286 ctx->state |= CCM_STATE__LENGTHS_SET;
287 return ccm_calculate_first_block_if_ready(ctx);
288 }
289
mbedtls_ccm_update_ad(mbedtls_ccm_context * ctx,const unsigned char * add,size_t add_len)290 int mbedtls_ccm_update_ad(mbedtls_ccm_context *ctx,
291 const unsigned char *add,
292 size_t add_len)
293 {
294 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
295 size_t use_len, offset;
296 #if !defined(MBEDTLS_BLOCK_CIPHER_C)
297 size_t olen;
298 #endif
299
300 if (ctx->state & CCM_STATE__ERROR) {
301 return MBEDTLS_ERR_CCM_BAD_INPUT;
302 }
303
304 if (add_len > 0) {
305 if (ctx->state & CCM_STATE__AUTH_DATA_FINISHED) {
306 return MBEDTLS_ERR_CCM_BAD_INPUT;
307 }
308
309 if (!(ctx->state & CCM_STATE__AUTH_DATA_STARTED)) {
310 if (add_len > ctx->add_len) {
311 return MBEDTLS_ERR_CCM_BAD_INPUT;
312 }
313
314 ctx->y[0] ^= (unsigned char) ((ctx->add_len >> 8) & 0xFF);
315 ctx->y[1] ^= (unsigned char) ((ctx->add_len) & 0xFF);
316
317 ctx->state |= CCM_STATE__AUTH_DATA_STARTED;
318 } else if (ctx->processed + add_len > ctx->add_len) {
319 return MBEDTLS_ERR_CCM_BAD_INPUT;
320 }
321
322 while (add_len > 0) {
323 offset = (ctx->processed + 2) % 16; /* account for y[0] and y[1]
324 * holding total auth data length */
325 use_len = 16 - offset;
326
327 if (use_len > add_len) {
328 use_len = add_len;
329 }
330
331 mbedtls_xor(ctx->y + offset, ctx->y + offset, add, use_len);
332
333 ctx->processed += use_len;
334 add_len -= use_len;
335 add += use_len;
336
337 if (use_len + offset == 16 || ctx->processed == ctx->add_len) {
338 #if defined(MBEDTLS_BLOCK_CIPHER_C)
339 ret = mbedtls_block_cipher_encrypt(&ctx->block_cipher_ctx, ctx->y, ctx->y);
340 #else
341 ret = mbedtls_cipher_update(&ctx->cipher_ctx, ctx->y, 16, ctx->y, &olen);
342 #endif
343 if (ret != 0) {
344 ctx->state |= CCM_STATE__ERROR;
345 return ret;
346 }
347 }
348 }
349
350 if (ctx->processed == ctx->add_len) {
351 ctx->state |= CCM_STATE__AUTH_DATA_FINISHED;
352 ctx->processed = 0; // prepare for mbedtls_ccm_update()
353 }
354 }
355
356 return 0;
357 }
358
mbedtls_ccm_update(mbedtls_ccm_context * ctx,const unsigned char * input,size_t input_len,unsigned char * output,size_t output_size,size_t * output_len)359 int mbedtls_ccm_update(mbedtls_ccm_context *ctx,
360 const unsigned char *input, size_t input_len,
361 unsigned char *output, size_t output_size,
362 size_t *output_len)
363 {
364 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
365 unsigned char i;
366 size_t use_len, offset;
367 #if !defined(MBEDTLS_BLOCK_CIPHER_C)
368 size_t olen;
369 #endif
370
371 unsigned char local_output[16];
372
373 if (ctx->state & CCM_STATE__ERROR) {
374 return MBEDTLS_ERR_CCM_BAD_INPUT;
375 }
376
377 /* Check against plaintext length only if performing operation with
378 * authentication
379 */
380 if (ctx->tag_len != 0 && ctx->processed + input_len > ctx->plaintext_len) {
381 return MBEDTLS_ERR_CCM_BAD_INPUT;
382 }
383
384 if (output_size < input_len) {
385 return MBEDTLS_ERR_CCM_BAD_INPUT;
386 }
387 *output_len = input_len;
388
389 ret = 0;
390
391 while (input_len > 0) {
392 offset = ctx->processed % 16;
393
394 use_len = 16 - offset;
395
396 if (use_len > input_len) {
397 use_len = input_len;
398 }
399
400 ctx->processed += use_len;
401
402 if (ctx->mode == MBEDTLS_CCM_ENCRYPT || \
403 ctx->mode == MBEDTLS_CCM_STAR_ENCRYPT) {
404 mbedtls_xor(ctx->y + offset, ctx->y + offset, input, use_len);
405
406 if (use_len + offset == 16 || ctx->processed == ctx->plaintext_len) {
407 #if defined(MBEDTLS_BLOCK_CIPHER_C)
408 ret = mbedtls_block_cipher_encrypt(&ctx->block_cipher_ctx, ctx->y, ctx->y);
409 #else
410 ret = mbedtls_cipher_update(&ctx->cipher_ctx, ctx->y, 16, ctx->y, &olen);
411 #endif
412 if (ret != 0) {
413 ctx->state |= CCM_STATE__ERROR;
414 goto exit;
415 }
416 }
417
418 ret = mbedtls_ccm_crypt(ctx, offset, use_len, input, output);
419 if (ret != 0) {
420 goto exit;
421 }
422 }
423
424 if (ctx->mode == MBEDTLS_CCM_DECRYPT || \
425 ctx->mode == MBEDTLS_CCM_STAR_DECRYPT) {
426 /* Since output may be in shared memory, we cannot be sure that
427 * it will contain what we wrote to it. Therefore, we should avoid using
428 * it as input to any operations.
429 * Write decrypted data to local_output to avoid using output variable as
430 * input in the XOR operation for Y.
431 */
432 ret = mbedtls_ccm_crypt(ctx, offset, use_len, input, local_output);
433 if (ret != 0) {
434 goto exit;
435 }
436
437 mbedtls_xor(ctx->y + offset, ctx->y + offset, local_output, use_len);
438
439 memcpy(output, local_output, use_len);
440
441 if (use_len + offset == 16 || ctx->processed == ctx->plaintext_len) {
442 #if defined(MBEDTLS_BLOCK_CIPHER_C)
443 ret = mbedtls_block_cipher_encrypt(&ctx->block_cipher_ctx, ctx->y, ctx->y);
444 #else
445 ret = mbedtls_cipher_update(&ctx->cipher_ctx, ctx->y, 16, ctx->y, &olen);
446 #endif
447 if (ret != 0) {
448 ctx->state |= CCM_STATE__ERROR;
449 goto exit;
450 }
451 }
452 }
453
454 if (use_len + offset == 16 || ctx->processed == ctx->plaintext_len) {
455 for (i = 0; i < ctx->q; i++) {
456 if (++(ctx->ctr)[15-i] != 0) {
457 break;
458 }
459 }
460 }
461
462 input_len -= use_len;
463 input += use_len;
464 output += use_len;
465 }
466
467 exit:
468 mbedtls_platform_zeroize(local_output, 16);
469
470 return ret;
471 }
472
mbedtls_ccm_finish(mbedtls_ccm_context * ctx,unsigned char * tag,size_t tag_len)473 int mbedtls_ccm_finish(mbedtls_ccm_context *ctx,
474 unsigned char *tag, size_t tag_len)
475 {
476 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
477 unsigned char i;
478
479 if (ctx->state & CCM_STATE__ERROR) {
480 return MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
481 }
482
483 if (ctx->add_len > 0 && !(ctx->state & CCM_STATE__AUTH_DATA_FINISHED)) {
484 return MBEDTLS_ERR_CCM_BAD_INPUT;
485 }
486
487 if (ctx->plaintext_len > 0 && ctx->processed != ctx->plaintext_len) {
488 return MBEDTLS_ERR_CCM_BAD_INPUT;
489 }
490
491 /*
492 * Authentication: reset counter and crypt/mask internal tag
493 */
494 for (i = 0; i < ctx->q; i++) {
495 ctx->ctr[15-i] = 0;
496 }
497
498 ret = mbedtls_ccm_crypt(ctx, 0, 16, ctx->y, ctx->y);
499 if (ret != 0) {
500 return ret;
501 }
502 if (tag != NULL) {
503 memcpy(tag, ctx->y, tag_len);
504 }
505 mbedtls_ccm_clear_state(ctx);
506
507 return 0;
508 }
509
510 /*
511 * Authenticated encryption or decryption
512 */
ccm_auth_crypt(mbedtls_ccm_context * ctx,int mode,size_t length,const unsigned char * iv,size_t iv_len,const unsigned char * add,size_t add_len,const unsigned char * input,unsigned char * output,unsigned char * tag,size_t tag_len)513 static int ccm_auth_crypt(mbedtls_ccm_context *ctx, int mode, size_t length,
514 const unsigned char *iv, size_t iv_len,
515 const unsigned char *add, size_t add_len,
516 const unsigned char *input, unsigned char *output,
517 unsigned char *tag, size_t tag_len)
518 {
519 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
520 size_t olen;
521
522 if ((ret = mbedtls_ccm_starts(ctx, mode, iv, iv_len)) != 0) {
523 return ret;
524 }
525
526 if ((ret = mbedtls_ccm_set_lengths(ctx, add_len, length, tag_len)) != 0) {
527 return ret;
528 }
529
530 if ((ret = mbedtls_ccm_update_ad(ctx, add, add_len)) != 0) {
531 return ret;
532 }
533
534 if ((ret = mbedtls_ccm_update(ctx, input, length,
535 output, length, &olen)) != 0) {
536 return ret;
537 }
538
539 if ((ret = mbedtls_ccm_finish(ctx, tag, tag_len)) != 0) {
540 return ret;
541 }
542
543 return 0;
544 }
545
546 /*
547 * Authenticated encryption
548 */
mbedtls_ccm_star_encrypt_and_tag(mbedtls_ccm_context * ctx,size_t length,const unsigned char * iv,size_t iv_len,const unsigned char * add,size_t add_len,const unsigned char * input,unsigned char * output,unsigned char * tag,size_t tag_len)549 int mbedtls_ccm_star_encrypt_and_tag(mbedtls_ccm_context *ctx, size_t length,
550 const unsigned char *iv, size_t iv_len,
551 const unsigned char *add, size_t add_len,
552 const unsigned char *input, unsigned char *output,
553 unsigned char *tag, size_t tag_len)
554 {
555 return ccm_auth_crypt(ctx, MBEDTLS_CCM_STAR_ENCRYPT, length, iv, iv_len,
556 add, add_len, input, output, tag, tag_len);
557 }
558
mbedtls_ccm_encrypt_and_tag(mbedtls_ccm_context * ctx,size_t length,const unsigned char * iv,size_t iv_len,const unsigned char * add,size_t add_len,const unsigned char * input,unsigned char * output,unsigned char * tag,size_t tag_len)559 int mbedtls_ccm_encrypt_and_tag(mbedtls_ccm_context *ctx, size_t length,
560 const unsigned char *iv, size_t iv_len,
561 const unsigned char *add, size_t add_len,
562 const unsigned char *input, unsigned char *output,
563 unsigned char *tag, size_t tag_len)
564 {
565 return ccm_auth_crypt(ctx, MBEDTLS_CCM_ENCRYPT, length, iv, iv_len,
566 add, add_len, input, output, tag, tag_len);
567 }
568
569 /*
570 * Authenticated decryption
571 */
mbedtls_ccm_compare_tags(const unsigned char * tag1,const unsigned char * tag2,size_t tag_len)572 static int mbedtls_ccm_compare_tags(const unsigned char *tag1,
573 const unsigned char *tag2,
574 size_t tag_len)
575 {
576 /* Check tag in "constant-time" */
577 int diff = mbedtls_ct_memcmp(tag1, tag2, tag_len);
578
579 if (diff != 0) {
580 return MBEDTLS_ERR_CCM_AUTH_FAILED;
581 }
582
583 return 0;
584 }
585
ccm_auth_decrypt(mbedtls_ccm_context * ctx,int mode,size_t length,const unsigned char * iv,size_t iv_len,const unsigned char * add,size_t add_len,const unsigned char * input,unsigned char * output,const unsigned char * tag,size_t tag_len)586 static int ccm_auth_decrypt(mbedtls_ccm_context *ctx, int mode, size_t length,
587 const unsigned char *iv, size_t iv_len,
588 const unsigned char *add, size_t add_len,
589 const unsigned char *input, unsigned char *output,
590 const unsigned char *tag, size_t tag_len)
591 {
592 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
593 unsigned char check_tag[16];
594
595 if ((ret = ccm_auth_crypt(ctx, mode, length,
596 iv, iv_len, add, add_len,
597 input, output, check_tag, tag_len)) != 0) {
598 return ret;
599 }
600
601 if ((ret = mbedtls_ccm_compare_tags(tag, check_tag, tag_len)) != 0) {
602 mbedtls_platform_zeroize(output, length);
603 return ret;
604 }
605
606 return 0;
607 }
608
mbedtls_ccm_star_auth_decrypt(mbedtls_ccm_context * ctx,size_t length,const unsigned char * iv,size_t iv_len,const unsigned char * add,size_t add_len,const unsigned char * input,unsigned char * output,const unsigned char * tag,size_t tag_len)609 int mbedtls_ccm_star_auth_decrypt(mbedtls_ccm_context *ctx, size_t length,
610 const unsigned char *iv, size_t iv_len,
611 const unsigned char *add, size_t add_len,
612 const unsigned char *input, unsigned char *output,
613 const unsigned char *tag, size_t tag_len)
614 {
615 return ccm_auth_decrypt(ctx, MBEDTLS_CCM_STAR_DECRYPT, length,
616 iv, iv_len, add, add_len,
617 input, output, tag, tag_len);
618 }
619
mbedtls_ccm_auth_decrypt(mbedtls_ccm_context * ctx,size_t length,const unsigned char * iv,size_t iv_len,const unsigned char * add,size_t add_len,const unsigned char * input,unsigned char * output,const unsigned char * tag,size_t tag_len)620 int mbedtls_ccm_auth_decrypt(mbedtls_ccm_context *ctx, size_t length,
621 const unsigned char *iv, size_t iv_len,
622 const unsigned char *add, size_t add_len,
623 const unsigned char *input, unsigned char *output,
624 const unsigned char *tag, size_t tag_len)
625 {
626 return ccm_auth_decrypt(ctx, MBEDTLS_CCM_DECRYPT, length,
627 iv, iv_len, add, add_len,
628 input, output, tag, tag_len);
629 }
630 #endif /* !MBEDTLS_CCM_ALT */
631
632 #if defined(MBEDTLS_SELF_TEST) && defined(MBEDTLS_CCM_GCM_CAN_AES)
633 /*
634 * Examples 1 to 3 from SP800-38C Appendix C
635 */
636
637 #define NB_TESTS 3
638 #define CCM_SELFTEST_PT_MAX_LEN 24
639 #define CCM_SELFTEST_CT_MAX_LEN 32
640 /*
641 * The data is the same for all tests, only the used length changes
642 */
643 static const unsigned char key_test_data[] = {
644 0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47,
645 0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f
646 };
647
648 static const unsigned char iv_test_data[] = {
649 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
650 0x18, 0x19, 0x1a, 0x1b
651 };
652
653 static const unsigned char ad_test_data[] = {
654 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
655 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
656 0x10, 0x11, 0x12, 0x13
657 };
658
659 static const unsigned char msg_test_data[CCM_SELFTEST_PT_MAX_LEN] = {
660 0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27,
661 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f,
662 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37,
663 };
664
665 static const size_t iv_len_test_data[NB_TESTS] = { 7, 8, 12 };
666 static const size_t add_len_test_data[NB_TESTS] = { 8, 16, 20 };
667 static const size_t msg_len_test_data[NB_TESTS] = { 4, 16, 24 };
668 static const size_t tag_len_test_data[NB_TESTS] = { 4, 6, 8 };
669
670 static const unsigned char res_test_data[NB_TESTS][CCM_SELFTEST_CT_MAX_LEN] = {
671 { 0x71, 0x62, 0x01, 0x5b, 0x4d, 0xac, 0x25, 0x5d },
672 { 0xd2, 0xa1, 0xf0, 0xe0, 0x51, 0xea, 0x5f, 0x62,
673 0x08, 0x1a, 0x77, 0x92, 0x07, 0x3d, 0x59, 0x3d,
674 0x1f, 0xc6, 0x4f, 0xbf, 0xac, 0xcd },
675 { 0xe3, 0xb2, 0x01, 0xa9, 0xf5, 0xb7, 0x1a, 0x7a,
676 0x9b, 0x1c, 0xea, 0xec, 0xcd, 0x97, 0xe7, 0x0b,
677 0x61, 0x76, 0xaa, 0xd9, 0xa4, 0x42, 0x8a, 0xa5,
678 0x48, 0x43, 0x92, 0xfb, 0xc1, 0xb0, 0x99, 0x51 }
679 };
680
mbedtls_ccm_self_test(int verbose)681 int mbedtls_ccm_self_test(int verbose)
682 {
683 mbedtls_ccm_context ctx;
684 /*
685 * Some hardware accelerators require the input and output buffers
686 * would be in RAM, because the flash is not accessible.
687 * Use buffers on the stack to hold the test vectors data.
688 */
689 unsigned char plaintext[CCM_SELFTEST_PT_MAX_LEN];
690 unsigned char ciphertext[CCM_SELFTEST_CT_MAX_LEN];
691 size_t i;
692 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
693
694 mbedtls_ccm_init(&ctx);
695
696 if (mbedtls_ccm_setkey(&ctx, MBEDTLS_CIPHER_ID_AES, key_test_data,
697 8 * sizeof(key_test_data)) != 0) {
698 if (verbose != 0) {
699 mbedtls_printf(" CCM: setup failed");
700 }
701
702 return 1;
703 }
704
705 for (i = 0; i < NB_TESTS; i++) {
706 if (verbose != 0) {
707 mbedtls_printf(" CCM-AES #%u: ", (unsigned int) i + 1);
708 }
709
710 memset(plaintext, 0, CCM_SELFTEST_PT_MAX_LEN);
711 memset(ciphertext, 0, CCM_SELFTEST_CT_MAX_LEN);
712 memcpy(plaintext, msg_test_data, msg_len_test_data[i]);
713
714 ret = mbedtls_ccm_encrypt_and_tag(&ctx, msg_len_test_data[i],
715 iv_test_data, iv_len_test_data[i],
716 ad_test_data, add_len_test_data[i],
717 plaintext, ciphertext,
718 ciphertext + msg_len_test_data[i],
719 tag_len_test_data[i]);
720
721 if (ret != 0 ||
722 memcmp(ciphertext, res_test_data[i],
723 msg_len_test_data[i] + tag_len_test_data[i]) != 0) {
724 if (verbose != 0) {
725 mbedtls_printf("failed\n");
726 }
727
728 return 1;
729 }
730 memset(plaintext, 0, CCM_SELFTEST_PT_MAX_LEN);
731
732 ret = mbedtls_ccm_auth_decrypt(&ctx, msg_len_test_data[i],
733 iv_test_data, iv_len_test_data[i],
734 ad_test_data, add_len_test_data[i],
735 ciphertext, plaintext,
736 ciphertext + msg_len_test_data[i],
737 tag_len_test_data[i]);
738
739 if (ret != 0 ||
740 memcmp(plaintext, msg_test_data, msg_len_test_data[i]) != 0) {
741 if (verbose != 0) {
742 mbedtls_printf("failed\n");
743 }
744
745 return 1;
746 }
747
748 if (verbose != 0) {
749 mbedtls_printf("passed\n");
750 }
751 }
752
753 mbedtls_ccm_free(&ctx);
754
755 if (verbose != 0) {
756 mbedtls_printf("\n");
757 }
758
759 return 0;
760 }
761
762 #endif /* MBEDTLS_SELF_TEST && MBEDTLS_AES_C */
763
764 #endif /* MBEDTLS_CCM_C */
765