dll/3rdparty/mbedtls/ccm.c

   1 /*
   2  *  NIST SP800-38C compliant CCM implementation
   3  *
   4  *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
   5  *  SPDX-License-Identifier: GPL-2.0
   6  *
   7  *  This program is free software; you can redistribute it and/or modify
   8  *  it under the terms of the GNU General Public License as published by
   9  *  the Free Software Foundation; either version 2 of the License, or
  10  *  (at your option) any later version.
  11  *
  12  *  This program is distributed in the hope that it will be useful,
  13  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  *  GNU General Public License for more details.
  16  *
  17  *  You should have received a copy of the GNU General Public License along
  18  *  with this program; if not, write to the Free Software Foundation, Inc.,
  19  *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  *  This file is part of mbed TLS (https://tls.mbed.org)
  22  */
  23
  24 /*
  25  * Definition of CCM:
  26  * http://csrc.nist.gov/publications/nistpubs/800-38C/SP800-38C_updated-July20_2007.pdf
  27  * RFC 3610 "Counter with CBC-MAC (CCM)"
  28  *
  29  * Related:
  30  * RFC 5116 "An Interface and Algorithms for Authenticated Encryption"
  31  */
  32
  33 #if !defined(MBEDTLS_CONFIG_FILE)
  34 #include "mbedtls/config.h"
  35 #else
  36 #include MBEDTLS_CONFIG_FILE
  37 #endif
  38
  39 #if defined(MBEDTLS_CCM_C)
  40
  41 #include "mbedtls/ccm.h"
  42
  43 #include <string.h>
  44
  45 #if defined(MBEDTLS_SELF_TEST) && defined(MBEDTLS_AES_C)
  46 #if defined(MBEDTLS_PLATFORM_C)
  47 #include "mbedtls/platform.h"
  48 #else
  49 #include <stdio.h>
  50 #define mbedtls_printf printf
  51 #endif /* MBEDTLS_PLATFORM_C */
  52 #endif /* MBEDTLS_SELF_TEST && MBEDTLS_AES_C */
  53
  54 #if !defined(MBEDTLS_CCM_ALT)
  55
  56 /* Implementation that should never be optimized out by the compiler */
  57 static void mbedtls_zeroize( void *v, size_t n ) {
  58     volatile unsigned char *p = (unsigned char*)v; while( n-- ) *p++ = 0;
  59 }
  60
  61 #define CCM_ENCRYPT 0
  62 #define CCM_DECRYPT 1
  63
  64 /*
  65  * Initialize context
  66  */
  67 void mbedtls_ccm_init( mbedtls_ccm_context *ctx )
  68 {
  69     memset( ctx, 0, sizeof( mbedtls_ccm_context ) );
  70 }
  71
  72 int 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     cipher_info = mbedtls_cipher_info_from_values( cipher, keybits, MBEDTLS_MODE_ECB );
  81     if( cipher_info == NULL )
  82         return( MBEDTLS_ERR_CCM_BAD_INPUT );
  83
  84     if( cipher_info->block_size != 16 )
  85         return( MBEDTLS_ERR_CCM_BAD_INPUT );
  86
  87     mbedtls_cipher_free( &ctx->cipher_ctx );
  88
  89     if( ( ret = mbedtls_cipher_setup( &ctx->cipher_ctx, cipher_info ) ) != 0 )
  90         return( ret );
  91
  92     if( ( ret = mbedtls_cipher_setkey( &ctx->cipher_ctx, key, keybits,
  93                                MBEDTLS_ENCRYPT ) ) != 0 )
  94     {
  95         return( ret );
  96     }
  97
  98     return( 0 );
  99 }
 100
 101 /*
 102  * Free context
 103  */
 104 void mbedtls_ccm_free( mbedtls_ccm_context *ctx )
 105 {
 106     mbedtls_cipher_free( &ctx->cipher_ctx );
 107     mbedtls_zeroize( ctx, sizeof( mbedtls_ccm_context ) );
 108 }
 109
 110 /*
 111  * Macros for common operations.
 112  * Results in smaller compiled code than static inline functions.
 113  */
 114
 115 /*
 116  * Update the CBC-MAC state in y using a block in b
 117  * (Always using b as the source helps the compiler optimise a bit better.)
 118  */
 119 #define UPDATE_CBC_MAC                                                      \
 120     for( i = 0; i < 16; i++ )                                               \
 121         y[i] ^= b[i];                                                       \
 122                                                                             \
 123     if( ( ret = mbedtls_cipher_update( &ctx->cipher_ctx, y, 16, y, &olen ) ) != 0 ) \
 124         return( ret );
 125
 126 /*
 127  * Encrypt or decrypt a partial block with CTR
 128  * Warning: using b for temporary storage! src and dst must not be b!
 129  * This avoids allocating one more 16 bytes buffer while allowing src == dst.
 130  */
 131 #define CTR_CRYPT( dst, src, len  )                                            \
 132     if( ( ret = mbedtls_cipher_update( &ctx->cipher_ctx, ctr, 16, b, &olen ) ) != 0 )  \
 133         return( ret );                                                         \
 134                                                                                \
 135     for( i = 0; i < len; i++ )                                                 \
 136         dst[i] = src[i] ^ b[i];
 137
 138 /*
 139  * Authenticated encryption or decryption
 140  */
 141 static int ccm_auth_crypt( mbedtls_ccm_context *ctx, int mode, size_t length,
 142                            const unsigned char *iv, size_t iv_len,
 143                            const unsigned char *add, size_t add_len,
 144                            const unsigned char *input, unsigned char *output,
 145                            unsigned char *tag, size_t tag_len )
 146 {
 147     int ret;
 148     unsigned char i;
 149     unsigned char q;
 150     size_t len_left, olen;
 151     unsigned char b[16];
 152     unsigned char y[16];
 153     unsigned char ctr[16];
 154     const unsigned char *src;
 155     unsigned char *dst;
 156
 157     /*
 158      * Check length requirements: SP800-38C A.1
 159      * Additional requirement: a < 2^16 - 2^8 to simplify the code.
 160      * 'length' checked later (when writing it to the first block)
 161      */
 162     if( tag_len < 4 || tag_len > 16 || tag_len % 2 != 0 )
 163         return( MBEDTLS_ERR_CCM_BAD_INPUT );
 164
 165     /* Also implies q is within bounds */
 166     if( iv_len < 7 || iv_len > 13 )
 167         return( MBEDTLS_ERR_CCM_BAD_INPUT );
 168
 169     if( add_len > 0xFF00 )
 170         return( MBEDTLS_ERR_CCM_BAD_INPUT );
 171
 172     q = 16 - 1 - (unsigned char) iv_len;
 173
 174     /*
 175      * First block B_0:
 176      * 0        .. 0        flags
 177      * 1        .. iv_len   nonce (aka iv)
 178      * iv_len+1 .. 15       length
 179      *
 180      * With flags as (bits):
 181      * 7        0
 182      * 6        add present?
 183      * 5 .. 3   (t - 2) / 2
 184      * 2 .. 0   q - 1
 185      */
 186     b[0] = 0;
 187     b[0] |= ( add_len > 0 ) << 6;
 188     b[0] |= ( ( tag_len - 2 ) / 2 ) << 3;
 189     b[0] |= q - 1;
 190
 191     memcpy( b + 1, iv, iv_len );
 192
 193     for( i = 0, len_left = length; i < q; i++, len_left >>= 8 )
 194         b[15-i] = (unsigned char)( len_left & 0xFF );
 195
 196     if( len_left > 0 )
 197         return( MBEDTLS_ERR_CCM_BAD_INPUT );
 198
 199
 200     /* Start CBC-MAC with first block */
 201     memset( y, 0, 16 );
 202     UPDATE_CBC_MAC;
 203
 204     /*
 205      * If there is additional data, update CBC-MAC with
 206      * add_len, add, 0 (padding to a block boundary)
 207      */
 208     if( add_len > 0 )
 209     {
 210         size_t use_len;
 211         len_left = add_len;
 212         src = add;
 213
 214         memset( b, 0, 16 );
 215         b[0] = (unsigned char)( ( add_len >> 8 ) & 0xFF );
 216         b[1] = (unsigned char)( ( add_len      ) & 0xFF );
 217
 218         use_len = len_left < 16 - 2 ? len_left : 16 - 2;
 219         memcpy( b + 2, src, use_len );
 220         len_left -= use_len;
 221         src += use_len;
 222
 223         UPDATE_CBC_MAC;
 224
 225         while( len_left > 0 )
 226         {
 227             use_len = len_left > 16 ? 16 : len_left;
 228
 229             memset( b, 0, 16 );
 230             memcpy( b, src, use_len );
 231             UPDATE_CBC_MAC;
 232
 233             len_left -= use_len;
 234             src += use_len;
 235         }
 236     }
 237
 238     /*
 239      * Prepare counter block for encryption:
 240      * 0        .. 0        flags
 241      * 1        .. iv_len   nonce (aka iv)
 242      * iv_len+1 .. 15       counter (initially 1)
 243      *
 244      * With flags as (bits):
 245      * 7 .. 3   0
 246      * 2 .. 0   q - 1
 247      */
 248     ctr[0] = q - 1;
 249     memcpy( ctr + 1, iv, iv_len );
 250     memset( ctr + 1 + iv_len, 0, q );
 251     ctr[15] = 1;
 252
 253     /*
 254      * Authenticate and {en,de}crypt the message.
 255      *
 256      * The only difference between encryption and decryption is
 257      * the respective order of authentication and {en,de}cryption.
 258      */
 259     len_left = length;
 260     src = input;
 261     dst = output;
 262
 263     while( len_left > 0 )
 264     {
 265         size_t use_len = len_left > 16 ? 16 : len_left;
 266
 267         if( mode == CCM_ENCRYPT )
 268         {
 269             memset( b, 0, 16 );
 270             memcpy( b, src, use_len );
 271             UPDATE_CBC_MAC;
 272         }
 273
 274         CTR_CRYPT( dst, src, use_len );
 275
 276         if( mode == CCM_DECRYPT )
 277         {
 278             memset( b, 0, 16 );
 279             memcpy( b, dst, use_len );
 280             UPDATE_CBC_MAC;
 281         }
 282
 283         dst += use_len;
 284         src += use_len;
 285         len_left -= use_len;
 286
 287         /*
 288          * Increment counter.
 289          * No need to check for overflow thanks to the length check above.
 290          */
 291         for( i = 0; i < q; i++ )
 292             if( ++ctr[15-i] != 0 )
 293                 break;
 294     }
 295
 296     /*
 297      * Authentication: reset counter and crypt/mask internal tag
 298      */
 299     for( i = 0; i < q; i++ )
 300         ctr[15-i] = 0;
 301
 302     CTR_CRYPT( y, y, 16 );
 303     memcpy( tag, y, tag_len );
 304
 305     return( 0 );
 306 }
 307
 308 /*
 309  * Authenticated encryption
 310  */
 311 int mbedtls_ccm_encrypt_and_tag( mbedtls_ccm_context *ctx, size_t length,
 312                          const unsigned char *iv, size_t iv_len,
 313                          const unsigned char *add, size_t add_len,
 314                          const unsigned char *input, unsigned char *output,
 315                          unsigned char *tag, size_t tag_len )
 316 {
 317     return( ccm_auth_crypt( ctx, CCM_ENCRYPT, length, iv, iv_len,
 318                             add, add_len, input, output, tag, tag_len ) );
 319 }
 320
 321 /*
 322  * Authenticated decryption
 323  */
 324 int mbedtls_ccm_auth_decrypt( mbedtls_ccm_context *ctx, size_t length,
 325                       const unsigned char *iv, size_t iv_len,
 326                       const unsigned char *add, size_t add_len,
 327                       const unsigned char *input, unsigned char *output,
 328                       const unsigned char *tag, size_t tag_len )
 329 {
 330     int ret;
 331     unsigned char check_tag[16];
 332     unsigned char i;
 333     int diff;
 334
 335     if( ( ret = ccm_auth_crypt( ctx, CCM_DECRYPT, length,
 336                                 iv, iv_len, add, add_len,
 337                                 input, output, check_tag, tag_len ) ) != 0 )
 338     {
 339         return( ret );
 340     }
 341
 342     /* Check tag in "constant-time" */
 343     for( diff = 0, i = 0; i < tag_len; i++ )
 344         diff |= tag[i] ^ check_tag[i];
 345
 346     if( diff != 0 )
 347     {
 348         mbedtls_zeroize( output, length );
 349         return( MBEDTLS_ERR_CCM_AUTH_FAILED );
 350     }
 351
 352     return( 0 );
 353 }
 354
 355 #endif /* !MBEDTLS_CCM_ALT */
 356
 357 #if defined(MBEDTLS_SELF_TEST) && defined(MBEDTLS_AES_C)
 358 /*
 359  * Examples 1 to 3 from SP800-38C Appendix C
 360  */
 361
 362 #define NB_TESTS 3
 363 #define CCM_SELFTEST_PT_MAX_LEN 24
 364 #define CCM_SELFTEST_CT_MAX_LEN 32
 365 /*
 366  * The data is the same for all tests, only the used length changes
 367  */
 368 static const unsigned char key[] = {
 369     0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47,
 370     0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f
 371 };
 372
 373 static const unsigned char iv[] = {
 374     0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
 375     0x18, 0x19, 0x1a, 0x1b
 376 };
 377
 378 static const unsigned char ad[] = {
 379     0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
 380     0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
 381     0x10, 0x11, 0x12, 0x13
 382 };
 383
 384 static const unsigned char msg[CCM_SELFTEST_PT_MAX_LEN] = {
 385     0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27,
 386     0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f,
 387     0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37,
 388 };
 389
 390 static const size_t iv_len [NB_TESTS] = { 7, 8,  12 };
 391 static const size_t add_len[NB_TESTS] = { 8, 16, 20 };
 392 static const size_t msg_len[NB_TESTS] = { 4, 16, 24 };
 393 static const size_t tag_len[NB_TESTS] = { 4, 6,  8  };
 394
 395 static const unsigned char res[NB_TESTS][CCM_SELFTEST_CT_MAX_LEN] = {
 396     {   0x71, 0x62, 0x01, 0x5b, 0x4d, 0xac, 0x25, 0x5d },
 397     {   0xd2, 0xa1, 0xf0, 0xe0, 0x51, 0xea, 0x5f, 0x62,
 398         0x08, 0x1a, 0x77, 0x92, 0x07, 0x3d, 0x59, 0x3d,
 399         0x1f, 0xc6, 0x4f, 0xbf, 0xac, 0xcd },
 400     {   0xe3, 0xb2, 0x01, 0xa9, 0xf5, 0xb7, 0x1a, 0x7a,
 401         0x9b, 0x1c, 0xea, 0xec, 0xcd, 0x97, 0xe7, 0x0b,
 402         0x61, 0x76, 0xaa, 0xd9, 0xa4, 0x42, 0x8a, 0xa5,
 403         0x48, 0x43, 0x92, 0xfb, 0xc1, 0xb0, 0x99, 0x51 }
 404 };
 405
 406 int mbedtls_ccm_self_test( int verbose )
 407 {
 408     mbedtls_ccm_context ctx;
 409     /*
 410      * Some hardware accelerators require the input and output buffers
 411      * would be in RAM, because the flash is not accessible.
 412      * Use buffers on the stack to hold the test vectors data.
 413      */
 414     unsigned char plaintext[CCM_SELFTEST_PT_MAX_LEN];
 415     unsigned char ciphertext[CCM_SELFTEST_CT_MAX_LEN];
 416     size_t i;
 417     int ret;
 418
 419     mbedtls_ccm_init( &ctx );
 420
 421     if( mbedtls_ccm_setkey( &ctx, MBEDTLS_CIPHER_ID_AES, key, 8 * sizeof key ) != 0 )
 422     {
 423         if( verbose != 0 )
 424             mbedtls_printf( "  CCM: setup failed" );
 425
 426         return( 1 );
 427     }
 428
 429     for( i = 0; i < NB_TESTS; i++ )
 430     {
 431         if( verbose != 0 )
 432             mbedtls_printf( "  CCM-AES #%u: ", (unsigned int) i + 1 );
 433
 434         memset( plaintext, 0, CCM_SELFTEST_PT_MAX_LEN );
 435         memset( ciphertext, 0, CCM_SELFTEST_CT_MAX_LEN );
 436         memcpy( plaintext, msg, msg_len[i] );
 437
 438         ret = mbedtls_ccm_encrypt_and_tag( &ctx, msg_len[i],
 439                                            iv, iv_len[i], ad, add_len[i],
 440                                            plaintext, ciphertext,
 441                                            ciphertext + msg_len[i], tag_len[i] );
 442
 443         if( ret != 0 ||
 444             memcmp( ciphertext, res[i], msg_len[i] + tag_len[i] ) != 0 )
 445         {
 446             if( verbose != 0 )
 447                 mbedtls_printf( "failed\n" );
 448
 449             return( 1 );
 450         }
 451         memset( plaintext, 0, CCM_SELFTEST_PT_MAX_LEN );
 452
 453         ret = mbedtls_ccm_auth_decrypt( &ctx, msg_len[i],
 454                                         iv, iv_len[i], ad, add_len[i],
 455                                         ciphertext, plaintext,
 456                                         ciphertext + msg_len[i], tag_len[i] );
 457
 458         if( ret != 0 ||
 459             memcmp( plaintext, msg, msg_len[i] ) != 0 )
 460         {
 461             if( verbose != 0 )
 462                 mbedtls_printf( "failed\n" );
 463
 464             return( 1 );
 465         }
 466
 467         if( verbose != 0 )
 468             mbedtls_printf( "passed\n" );
 469     }
 470
 471     mbedtls_ccm_free( &ctx );
 472
 473     if( verbose != 0 )
 474         mbedtls_printf( "\n" );
 475
 476     return( 0 );
 477 }
 478
 479 #endif /* MBEDTLS_SELF_TEST && MBEDTLS_AES_C */
 480
 481 #endif /* MBEDTLS_CCM_C */