source: azure_iot_hub_mbedtls/trunk/mbedtls-2.16.1/library/ccm.c@ 398

Last change on this file since 398 was 398, checked in by coas-nagasima, 5 years ago

mbedTLS版Azure IoT Hub接続サンプルのソースコードを追加
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1/*
2 * NIST SP800-38C compliant CCM implementation
3 *
4 * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
5 * SPDX-License-Identifier: Apache-2.0
6 *
7 * Licensed under the Apache License, Version 2.0 (the "License"); you may
8 * not use this file except in compliance with the License.
9 * You may obtain a copy of the License at
10 *
11 * http://www.apache.org/licenses/LICENSE-2.0
12 *
13 * Unless required by applicable law or agreed to in writing, software
14 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
15 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 * See the License for the specific language governing permissions and
17 * limitations under the License.
18 *
19 * This file is part of mbed TLS (https://tls.mbed.org)
20 */
21
22/*
23 * Definition of CCM:
24 * http://csrc.nist.gov/publications/nistpubs/800-38C/SP800-38C_updated-July20_2007.pdf
25 * RFC 3610 "Counter with CBC-MAC (CCM)"
26 *
27 * Related:
28 * RFC 5116 "An Interface and Algorithms for Authenticated Encryption"
29 */
30
31#if !defined(MBEDTLS_CONFIG_FILE)
32#include "mbedtls/config.h"
33#else
34#include MBEDTLS_CONFIG_FILE
35#endif
36
37#if defined(MBEDTLS_CCM_C)
38
39#include "mbedtls/ccm.h"
40#include "mbedtls/platform_util.h"
41
42#include <string.h>
43
44#if defined(MBEDTLS_SELF_TEST) && defined(MBEDTLS_AES_C)
45#if defined(MBEDTLS_PLATFORM_C)
46#include "mbedtls/platform.h"
47#else
48#include <stdio.h>
49#define mbedtls_printf printf
50#endif /* MBEDTLS_PLATFORM_C */
51#endif /* MBEDTLS_SELF_TEST && MBEDTLS_AES_C */
52
53#if !defined(MBEDTLS_CCM_ALT)
54
55#define CCM_VALIDATE_RET( cond ) \
56 MBEDTLS_INTERNAL_VALIDATE_RET( cond, MBEDTLS_ERR_CCM_BAD_INPUT )
57#define CCM_VALIDATE( cond ) \
58 MBEDTLS_INTERNAL_VALIDATE( cond )
59
60#define CCM_ENCRYPT 0
61#define CCM_DECRYPT 1
62
63/*
64 * Initialize context
65 */
66void mbedtls_ccm_init( mbedtls_ccm_context *ctx )
67{
68 CCM_VALIDATE( ctx != NULL );
69 memset( ctx, 0, sizeof( mbedtls_ccm_context ) );
70}
71
72int mbedtls_ccm_setkey( mbedtls_ccm_context *ctx,
73 mbedtls_cipher_id_t cipher,
74 const unsigned char *key,
75 unsigned int keybits )
76{
77 int ret;
78 const mbedtls_cipher_info_t *cipher_info;
79
80 CCM_VALIDATE_RET( ctx != NULL );
81 CCM_VALIDATE_RET( key != NULL );
82
83 cipher_info = mbedtls_cipher_info_from_values( cipher, keybits, MBEDTLS_MODE_ECB );
84 if( cipher_info == NULL )
85 return( MBEDTLS_ERR_CCM_BAD_INPUT );
86
87 if( cipher_info->block_size != 16 )
88 return( MBEDTLS_ERR_CCM_BAD_INPUT );
89
90 mbedtls_cipher_free( &ctx->cipher_ctx );
91
92 if( ( ret = mbedtls_cipher_setup( &ctx->cipher_ctx, cipher_info ) ) != 0 )
93 return( ret );
94
95 if( ( ret = mbedtls_cipher_setkey( &ctx->cipher_ctx, key, keybits,
96 MBEDTLS_ENCRYPT ) ) != 0 )
97 {
98 return( ret );
99 }
100
101 return( 0 );
102}
103
104/*
105 * Free context
106 */
107void mbedtls_ccm_free( mbedtls_ccm_context *ctx )
108{
109 if( ctx == NULL )
110 return;
111 mbedtls_cipher_free( &ctx->cipher_ctx );
112 mbedtls_platform_zeroize( ctx, sizeof( mbedtls_ccm_context ) );
113}
114
115/*
116 * Macros for common operations.
117 * Results in smaller compiled code than static inline functions.
118 */
119
120/*
121 * Update the CBC-MAC state in y using a block in b
122 * (Always using b as the source helps the compiler optimise a bit better.)
123 */
124#define UPDATE_CBC_MAC \
125 for( i = 0; i < 16; i++ ) \
126 y[i] ^= b[i]; \
127 \
128 if( ( ret = mbedtls_cipher_update( &ctx->cipher_ctx, y, 16, y, &olen ) ) != 0 ) \
129 return( ret );
130
131/*
132 * Encrypt or decrypt a partial block with CTR
133 * Warning: using b for temporary storage! src and dst must not be b!
134 * This avoids allocating one more 16 bytes buffer while allowing src == dst.
135 */
136#define CTR_CRYPT( dst, src, len ) \
137 if( ( ret = mbedtls_cipher_update( &ctx->cipher_ctx, ctr, 16, b, &olen ) ) != 0 ) \
138 return( ret ); \
139 \
140 for( i = 0; i < len; i++ ) \
141 dst[i] = src[i] ^ b[i];
142
143/*
144 * Authenticated encryption or decryption
145 */
146static int ccm_auth_crypt( mbedtls_ccm_context *ctx, int mode, size_t length,
147 const unsigned char *iv, size_t iv_len,
148 const unsigned char *add, size_t add_len,
149 const unsigned char *input, unsigned char *output,
150 unsigned char *tag, size_t tag_len )
151{
152 int ret;
153 unsigned char i;
154 unsigned char q;
155 size_t len_left, olen;
156 unsigned char b[16];
157 unsigned char y[16];
158 unsigned char ctr[16];
159 const unsigned char *src;
160 unsigned char *dst;
161
162 /*
163 * Check length requirements: SP800-38C A.1
164 * Additional requirement: a < 2^16 - 2^8 to simplify the code.
165 * 'length' checked later (when writing it to the first block)
166 *
167 * Also, loosen the requirements to enable support for CCM* (IEEE 802.15.4).
168 */
169 if( tag_len == 2 || tag_len > 16 || tag_len % 2 != 0 )
170 return( MBEDTLS_ERR_CCM_BAD_INPUT );
171
172 /* Also implies q is within bounds */
173 if( iv_len < 7 || iv_len > 13 )
174 return( MBEDTLS_ERR_CCM_BAD_INPUT );
175
176 if( add_len > 0xFF00 )
177 return( MBEDTLS_ERR_CCM_BAD_INPUT );
178
179 q = 16 - 1 - (unsigned char) iv_len;
180
181 /*
182 * First block B_0:
183 * 0 .. 0 flags
184 * 1 .. iv_len nonce (aka iv)
185 * iv_len+1 .. 15 length
186 *
187 * With flags as (bits):
188 * 7 0
189 * 6 add present?
190 * 5 .. 3 (t - 2) / 2
191 * 2 .. 0 q - 1
192 */
193 b[0] = 0;
194 b[0] |= ( add_len > 0 ) << 6;
195 b[0] |= ( ( tag_len - 2 ) / 2 ) << 3;
196 b[0] |= q - 1;
197
198 memcpy( b + 1, iv, iv_len );
199
200 for( i = 0, len_left = length; i < q; i++, len_left >>= 8 )
201 b[15-i] = (unsigned char)( len_left & 0xFF );
202
203 if( len_left > 0 )
204 return( MBEDTLS_ERR_CCM_BAD_INPUT );
205
206
207 /* Start CBC-MAC with first block */
208 memset( y, 0, 16 );
209 UPDATE_CBC_MAC;
210
211 /*
212 * If there is additional data, update CBC-MAC with
213 * add_len, add, 0 (padding to a block boundary)
214 */
215 if( add_len > 0 )
216 {
217 size_t use_len;
218 len_left = add_len;
219 src = add;
220
221 memset( b, 0, 16 );
222 b[0] = (unsigned char)( ( add_len >> 8 ) & 0xFF );
223 b[1] = (unsigned char)( ( add_len ) & 0xFF );
224
225 use_len = len_left < 16 - 2 ? len_left : 16 - 2;
226 memcpy( b + 2, src, use_len );
227 len_left -= use_len;
228 src += use_len;
229
230 UPDATE_CBC_MAC;
231
232 while( len_left > 0 )
233 {
234 use_len = len_left > 16 ? 16 : len_left;
235
236 memset( b, 0, 16 );
237 memcpy( b, src, use_len );
238 UPDATE_CBC_MAC;
239
240 len_left -= use_len;
241 src += use_len;
242 }
243 }
244
245 /*
246 * Prepare counter block for encryption:
247 * 0 .. 0 flags
248 * 1 .. iv_len nonce (aka iv)
249 * iv_len+1 .. 15 counter (initially 1)
250 *
251 * With flags as (bits):
252 * 7 .. 3 0
253 * 2 .. 0 q - 1
254 */
255 ctr[0] = q - 1;
256 memcpy( ctr + 1, iv, iv_len );
257 memset( ctr + 1 + iv_len, 0, q );
258 ctr[15] = 1;
259
260 /*
261 * Authenticate and {en,de}crypt the message.
262 *
263 * The only difference between encryption and decryption is
264 * the respective order of authentication and {en,de}cryption.
265 */
266 len_left = length;
267 src = input;
268 dst = output;
269
270 while( len_left > 0 )
271 {
272 size_t use_len = len_left > 16 ? 16 : len_left;
273
274 if( mode == CCM_ENCRYPT )
275 {
276 memset( b, 0, 16 );
277 memcpy( b, src, use_len );
278 UPDATE_CBC_MAC;
279 }
280
281 CTR_CRYPT( dst, src, use_len );
282
283 if( mode == CCM_DECRYPT )
284 {
285 memset( b, 0, 16 );
286 memcpy( b, dst, use_len );
287 UPDATE_CBC_MAC;
288 }
289
290 dst += use_len;
291 src += use_len;
292 len_left -= use_len;
293
294 /*
295 * Increment counter.
296 * No need to check for overflow thanks to the length check above.
297 */
298 for( i = 0; i < q; i++ )
299 if( ++ctr[15-i] != 0 )
300 break;
301 }
302
303 /*
304 * Authentication: reset counter and crypt/mask internal tag
305 */
306 for( i = 0; i < q; i++ )
307 ctr[15-i] = 0;
308
309 CTR_CRYPT( y, y, 16 );
310 memcpy( tag, y, tag_len );
311
312 return( 0 );
313}
314
315/*
316 * Authenticated encryption
317 */
318int mbedtls_ccm_star_encrypt_and_tag( mbedtls_ccm_context *ctx, size_t length,
319 const unsigned char *iv, size_t iv_len,
320 const unsigned char *add, size_t add_len,
321 const unsigned char *input, unsigned char *output,
322 unsigned char *tag, size_t tag_len )
323{
324 CCM_VALIDATE_RET( ctx != NULL );
325 CCM_VALIDATE_RET( iv != NULL );
326 CCM_VALIDATE_RET( add_len == 0 || add != NULL );
327 CCM_VALIDATE_RET( length == 0 || input != NULL );
328 CCM_VALIDATE_RET( length == 0 || output != NULL );
329 CCM_VALIDATE_RET( tag_len == 0 || tag != NULL );
330 return( ccm_auth_crypt( ctx, CCM_ENCRYPT, length, iv, iv_len,
331 add, add_len, input, output, tag, tag_len ) );
332}
333
334int mbedtls_ccm_encrypt_and_tag( mbedtls_ccm_context *ctx, size_t length,
335 const unsigned char *iv, size_t iv_len,
336 const unsigned char *add, size_t add_len,
337 const unsigned char *input, unsigned char *output,
338 unsigned char *tag, size_t tag_len )
339{
340 CCM_VALIDATE_RET( ctx != NULL );
341 CCM_VALIDATE_RET( iv != NULL );
342 CCM_VALIDATE_RET( add_len == 0 || add != NULL );
343 CCM_VALIDATE_RET( length == 0 || input != NULL );
344 CCM_VALIDATE_RET( length == 0 || output != NULL );
345 CCM_VALIDATE_RET( tag_len == 0 || tag != NULL );
346 if( tag_len == 0 )
347 return( MBEDTLS_ERR_CCM_BAD_INPUT );
348
349 return( mbedtls_ccm_star_encrypt_and_tag( ctx, length, iv, iv_len, add,
350 add_len, input, output, tag, tag_len ) );
351}
352
353/*
354 * Authenticated decryption
355 */
356int mbedtls_ccm_star_auth_decrypt( mbedtls_ccm_context *ctx, size_t length,
357 const unsigned char *iv, size_t iv_len,
358 const unsigned char *add, size_t add_len,
359 const unsigned char *input, unsigned char *output,
360 const unsigned char *tag, size_t tag_len )
361{
362 int ret;
363 unsigned char check_tag[16];
364 unsigned char i;
365 int diff;
366
367 CCM_VALIDATE_RET( ctx != NULL );
368 CCM_VALIDATE_RET( iv != NULL );
369 CCM_VALIDATE_RET( add_len == 0 || add != NULL );
370 CCM_VALIDATE_RET( length == 0 || input != NULL );
371 CCM_VALIDATE_RET( length == 0 || output != NULL );
372 CCM_VALIDATE_RET( tag_len == 0 || tag != NULL );
373
374 if( ( ret = ccm_auth_crypt( ctx, CCM_DECRYPT, length,
375 iv, iv_len, add, add_len,
376 input, output, check_tag, tag_len ) ) != 0 )
377 {
378 return( ret );
379 }
380
381 /* Check tag in "constant-time" */
382 for( diff = 0, i = 0; i < tag_len; i++ )
383 diff |= tag[i] ^ check_tag[i];
384
385 if( diff != 0 )
386 {
387 mbedtls_platform_zeroize( output, length );
388 return( MBEDTLS_ERR_CCM_AUTH_FAILED );
389 }
390
391 return( 0 );
392}
393
394int mbedtls_ccm_auth_decrypt( mbedtls_ccm_context *ctx, size_t length,
395 const unsigned char *iv, size_t iv_len,
396 const unsigned char *add, size_t add_len,
397 const unsigned char *input, unsigned char *output,
398 const unsigned char *tag, size_t tag_len )
399{
400 CCM_VALIDATE_RET( ctx != NULL );
401 CCM_VALIDATE_RET( iv != NULL );
402 CCM_VALIDATE_RET( add_len == 0 || add != NULL );
403 CCM_VALIDATE_RET( length == 0 || input != NULL );
404 CCM_VALIDATE_RET( length == 0 || output != NULL );
405 CCM_VALIDATE_RET( tag_len == 0 || tag != NULL );
406
407 if( tag_len == 0 )
408 return( MBEDTLS_ERR_CCM_BAD_INPUT );
409
410 return( mbedtls_ccm_star_auth_decrypt( ctx, length, iv, iv_len, add,
411 add_len, input, output, tag, tag_len ) );
412}
413#endif /* !MBEDTLS_CCM_ALT */
414
415#if defined(MBEDTLS_SELF_TEST) && defined(MBEDTLS_AES_C)
416/*
417 * Examples 1 to 3 from SP800-38C Appendix C
418 */
419
420#define NB_TESTS 3
421#define CCM_SELFTEST_PT_MAX_LEN 24
422#define CCM_SELFTEST_CT_MAX_LEN 32
423/*
424 * The data is the same for all tests, only the used length changes
425 */
426static const unsigned char key[] = {
427 0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47,
428 0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f
429};
430
431static const unsigned char iv[] = {
432 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
433 0x18, 0x19, 0x1a, 0x1b
434};
435
436static const unsigned char ad[] = {
437 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
438 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
439 0x10, 0x11, 0x12, 0x13
440};
441
442static const unsigned char msg[CCM_SELFTEST_PT_MAX_LEN] = {
443 0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27,
444 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f,
445 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37,
446};
447
448static const size_t iv_len [NB_TESTS] = { 7, 8, 12 };
449static const size_t add_len[NB_TESTS] = { 8, 16, 20 };
450static const size_t msg_len[NB_TESTS] = { 4, 16, 24 };
451static const size_t tag_len[NB_TESTS] = { 4, 6, 8 };
452
453static const unsigned char res[NB_TESTS][CCM_SELFTEST_CT_MAX_LEN] = {
454 { 0x71, 0x62, 0x01, 0x5b, 0x4d, 0xac, 0x25, 0x5d },
455 { 0xd2, 0xa1, 0xf0, 0xe0, 0x51, 0xea, 0x5f, 0x62,
456 0x08, 0x1a, 0x77, 0x92, 0x07, 0x3d, 0x59, 0x3d,
457 0x1f, 0xc6, 0x4f, 0xbf, 0xac, 0xcd },
458 { 0xe3, 0xb2, 0x01, 0xa9, 0xf5, 0xb7, 0x1a, 0x7a,
459 0x9b, 0x1c, 0xea, 0xec, 0xcd, 0x97, 0xe7, 0x0b,
460 0x61, 0x76, 0xaa, 0xd9, 0xa4, 0x42, 0x8a, 0xa5,
461 0x48, 0x43, 0x92, 0xfb, 0xc1, 0xb0, 0x99, 0x51 }
462};
463
464int mbedtls_ccm_self_test( int verbose )
465{
466 mbedtls_ccm_context ctx;
467 /*
468 * Some hardware accelerators require the input and output buffers
469 * would be in RAM, because the flash is not accessible.
470 * Use buffers on the stack to hold the test vectors data.
471 */
472 unsigned char plaintext[CCM_SELFTEST_PT_MAX_LEN];
473 unsigned char ciphertext[CCM_SELFTEST_CT_MAX_LEN];
474 size_t i;
475 int ret;
476
477 mbedtls_ccm_init( &ctx );
478
479 if( mbedtls_ccm_setkey( &ctx, MBEDTLS_CIPHER_ID_AES, key, 8 * sizeof key ) != 0 )
480 {
481 if( verbose != 0 )
482 mbedtls_printf( " CCM: setup failed" );
483
484 return( 1 );
485 }
486
487 for( i = 0; i < NB_TESTS; i++ )
488 {
489 if( verbose != 0 )
490 mbedtls_printf( " CCM-AES #%u: ", (unsigned int) i + 1 );
491
492 memset( plaintext, 0, CCM_SELFTEST_PT_MAX_LEN );
493 memset( ciphertext, 0, CCM_SELFTEST_CT_MAX_LEN );
494 memcpy( plaintext, msg, msg_len[i] );
495
496 ret = mbedtls_ccm_encrypt_and_tag( &ctx, msg_len[i],
497 iv, iv_len[i], ad, add_len[i],
498 plaintext, ciphertext,
499 ciphertext + msg_len[i], tag_len[i] );
500
501 if( ret != 0 ||
502 memcmp( ciphertext, res[i], msg_len[i] + tag_len[i] ) != 0 )
503 {
504 if( verbose != 0 )
505 mbedtls_printf( "failed\n" );
506
507 return( 1 );
508 }
509 memset( plaintext, 0, CCM_SELFTEST_PT_MAX_LEN );
510
511 ret = mbedtls_ccm_auth_decrypt( &ctx, msg_len[i],
512 iv, iv_len[i], ad, add_len[i],
513 ciphertext, plaintext,
514 ciphertext + msg_len[i], tag_len[i] );
515
516 if( ret != 0 ||
517 memcmp( plaintext, msg, msg_len[i] ) != 0 )
518 {
519 if( verbose != 0 )
520 mbedtls_printf( "failed\n" );
521
522 return( 1 );
523 }
524
525 if( verbose != 0 )
526 mbedtls_printf( "passed\n" );
527 }
528
529 mbedtls_ccm_free( &ctx );
530
531 if( verbose != 0 )
532 mbedtls_printf( "\n" );
533
534 return( 0 );
535}
536
537#endif /* MBEDTLS_SELF_TEST && MBEDTLS_AES_C */
538
539#endif /* MBEDTLS_CCM_C */
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