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Paul Bakker20a78082011-01-21 09:32:12 +00001/*
2 * \brief Generic file encryption program using generic wrappers for configured
3 * security.
4 *
Manuel Pégourié-Gonnard6fb81872015-07-27 11:11:48 +02005 * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
Manuel Pégourié-Gonnard37ff1402015-09-04 14:21:07 +02006 * SPDX-License-Identifier: Apache-2.0
7 *
8 * Licensed under the Apache License, Version 2.0 (the "License"); you may
9 * not use this file except in compliance with the License.
10 * You may obtain a copy of the License at
11 *
12 * http://www.apache.org/licenses/LICENSE-2.0
13 *
14 * Unless required by applicable law or agreed to in writing, software
15 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
16 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
17 * See the License for the specific language governing permissions and
18 * limitations under the License.
Paul Bakker20a78082011-01-21 09:32:12 +000019 *
Manuel Pégourié-Gonnardfe446432015-03-06 13:17:10 +000020 * This file is part of mbed TLS (https://tls.mbed.org)
Paul Bakker20a78082011-01-21 09:32:12 +000021 */
22
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +020023#if !defined(MBEDTLS_CONFIG_FILE)
Manuel Pégourié-Gonnard7f809972015-03-09 17:05:11 +000024#include "mbedtls/config.h"
Manuel Pégourié-Gonnardcef4ad22014-04-29 12:39:06 +020025#else
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +020026#include MBEDTLS_CONFIG_FILE
Manuel Pégourié-Gonnardcef4ad22014-04-29 12:39:06 +020027#endif
Paul Bakker20a78082011-01-21 09:32:12 +000028
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +020029#if defined(MBEDTLS_PLATFORM_C)
Manuel Pégourié-Gonnard7f809972015-03-09 17:05:11 +000030#include "mbedtls/platform.h"
Rich Evansf90016a2015-01-19 14:26:37 +000031#else
Rich Evans18b78c72015-02-11 14:06:19 +000032#include <stdio.h>
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +020033#define mbedtls_fprintf fprintf
34#define mbedtls_printf printf
Rich Evans18b78c72015-02-11 14:06:19 +000035#endif
36
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +020037#if defined(MBEDTLS_CIPHER_C) && defined(MBEDTLS_MD_C) && \
38 defined(MBEDTLS_FS_IO)
Manuel Pégourié-Gonnard7f809972015-03-09 17:05:11 +000039#include "mbedtls/cipher.h"
40#include "mbedtls/md.h"
Rich Evans18b78c72015-02-11 14:06:19 +000041
42#include <stdio.h>
43#include <stdlib.h>
44#include <string.h>
Rich Evansf90016a2015-01-19 14:26:37 +000045#endif
46
Paul Bakker494c0b82011-04-24 15:30:07 +000047#if defined(_WIN32)
Paul Bakker20a78082011-01-21 09:32:12 +000048#include <windows.h>
Paul Bakkercce9d772011-11-18 14:26:47 +000049#if !defined(_WIN32_WCE)
Paul Bakker20a78082011-01-21 09:32:12 +000050#include <io.h>
Paul Bakkercce9d772011-11-18 14:26:47 +000051#endif
Paul Bakker20a78082011-01-21 09:32:12 +000052#else
53#include <sys/types.h>
54#include <unistd.h>
55#endif
56
Paul Bakker20a78082011-01-21 09:32:12 +000057#define MODE_ENCRYPT 0
58#define MODE_DECRYPT 1
59
60#define USAGE \
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +020061 "\n crypt_and_hash <mode> <input filename> <output filename> <cipher> <mbedtls_md> <key>\n" \
Paul Bakker20a78082011-01-21 09:32:12 +000062 "\n <mode>: 0 = encrypt, 1 = decrypt\n" \
63 "\n example: crypt_and_hash 0 file file.aes AES-128-CBC SHA1 hex:E76B2413958B00E193\n" \
64 "\n"
65
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +020066#if !defined(MBEDTLS_CIPHER_C) || !defined(MBEDTLS_MD_C) || \
67 !defined(MBEDTLS_FS_IO)
Rich Evans85b05ec2015-02-12 11:37:29 +000068int main( void )
Paul Bakker5690efc2011-05-26 13:16:06 +000069{
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +020070 mbedtls_printf("MBEDTLS_CIPHER_C and/or MBEDTLS_MD_C and/or MBEDTLS_FS_IO not defined.\n");
Paul Bakker5690efc2011-05-26 13:16:06 +000071 return( 0 );
72}
73#else
Paul Bakker20a78082011-01-21 09:32:12 +000074int main( int argc, char *argv[] )
75{
Paul Bakker25b5fe52011-05-26 14:02:58 +000076 int ret = 1, i, n;
Paul Bakker23986e52011-04-24 08:57:21 +000077 int mode, lastn;
Paul Bakker25b5fe52011-05-26 14:02:58 +000078 size_t keylen, ilen, olen;
Paul Bakker20a78082011-01-21 09:32:12 +000079 FILE *fkey, *fin = NULL, *fout = NULL;
80
81 char *p;
82 unsigned char IV[16];
83 unsigned char key[512];
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +020084 unsigned char digest[MBEDTLS_MD_MAX_SIZE];
Paul Bakker20a78082011-01-21 09:32:12 +000085 unsigned char buffer[1024];
86 unsigned char output[1024];
Paul Bakker424cd692013-10-31 14:22:08 +010087 unsigned char diff;
Paul Bakker20a78082011-01-21 09:32:12 +000088
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +020089 const mbedtls_cipher_info_t *cipher_info;
90 const mbedtls_md_info_t *md_info;
91 mbedtls_cipher_context_t cipher_ctx;
92 mbedtls_md_context_t md_ctx;
Paul Bakkercce9d772011-11-18 14:26:47 +000093#if defined(_WIN32_WCE)
94 long filesize, offset;
95#elif defined(_WIN32)
Paul Bakker20a78082011-01-21 09:32:12 +000096 LARGE_INTEGER li_size;
97 __int64 filesize, offset;
98#else
99 off_t filesize, offset;
100#endif
101
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200102 mbedtls_cipher_init( &cipher_ctx );
103 mbedtls_md_init( &md_ctx );
Paul Bakker20a78082011-01-21 09:32:12 +0000104
105 /*
106 * Parse the command-line arguments.
107 */
108 if( argc != 7 )
109 {
110 const int *list;
111
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200112 mbedtls_printf( USAGE );
Paul Bakker20a78082011-01-21 09:32:12 +0000113
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200114 mbedtls_printf( "Available ciphers:\n" );
115 list = mbedtls_cipher_list();
Paul Bakker20a78082011-01-21 09:32:12 +0000116 while( *list )
117 {
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200118 cipher_info = mbedtls_cipher_info_from_type( *list );
119 mbedtls_printf( " %s\n", cipher_info->name );
Paul Bakker20a78082011-01-21 09:32:12 +0000120 list++;
121 }
122
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200123 mbedtls_printf( "\nAvailable message digests:\n" );
124 list = mbedtls_md_list();
Paul Bakker20a78082011-01-21 09:32:12 +0000125 while( *list )
126 {
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200127 md_info = mbedtls_md_info_from_type( *list );
128 mbedtls_printf( " %s\n", mbedtls_md_get_name( md_info ) );
Paul Bakker20a78082011-01-21 09:32:12 +0000129 list++;
130 }
131
Paul Bakkercce9d772011-11-18 14:26:47 +0000132#if defined(_WIN32)
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200133 mbedtls_printf( "\n Press Enter to exit this program.\n" );
Paul Bakker20a78082011-01-21 09:32:12 +0000134 fflush( stdout ); getchar();
135#endif
136
137 goto exit;
138 }
139
140 mode = atoi( argv[1] );
141
142 if( mode != MODE_ENCRYPT && mode != MODE_DECRYPT )
143 {
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200144 mbedtls_fprintf( stderr, "invalid operation mode\n" );
Paul Bakker20a78082011-01-21 09:32:12 +0000145 goto exit;
146 }
147
148 if( strcmp( argv[2], argv[3] ) == 0 )
149 {
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200150 mbedtls_fprintf( stderr, "input and output filenames must differ\n" );
Paul Bakker20a78082011-01-21 09:32:12 +0000151 goto exit;
152 }
153
154 if( ( fin = fopen( argv[2], "rb" ) ) == NULL )
155 {
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200156 mbedtls_fprintf( stderr, "fopen(%s,rb) failed\n", argv[2] );
Paul Bakker20a78082011-01-21 09:32:12 +0000157 goto exit;
158 }
159
160 if( ( fout = fopen( argv[3], "wb+" ) ) == NULL )
161 {
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200162 mbedtls_fprintf( stderr, "fopen(%s,wb+) failed\n", argv[3] );
Paul Bakker20a78082011-01-21 09:32:12 +0000163 goto exit;
164 }
165
166 /*
167 * Read the Cipher and MD from the command line
168 */
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200169 cipher_info = mbedtls_cipher_info_from_string( argv[4] );
Paul Bakker20a78082011-01-21 09:32:12 +0000170 if( cipher_info == NULL )
171 {
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200172 mbedtls_fprintf( stderr, "Cipher '%s' not found\n", argv[4] );
Paul Bakker20a78082011-01-21 09:32:12 +0000173 goto exit;
174 }
Manuel Pégourié-Gonnard8473f872015-05-14 13:51:45 +0200175 if( ( ret = mbedtls_cipher_setup( &cipher_ctx, cipher_info) ) != 0 )
Paul Bakkercbe3d0d2014-04-17 16:00:59 +0200176 {
Manuel Pégourié-Gonnard8473f872015-05-14 13:51:45 +0200177 mbedtls_fprintf( stderr, "mbedtls_cipher_setup failed\n" );
Paul Bakkercbe3d0d2014-04-17 16:00:59 +0200178 goto exit;
179 }
Paul Bakker20a78082011-01-21 09:32:12 +0000180
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200181 md_info = mbedtls_md_info_from_string( argv[5] );
Paul Bakker20a78082011-01-21 09:32:12 +0000182 if( md_info == NULL )
183 {
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200184 mbedtls_fprintf( stderr, "Message Digest '%s' not found\n", argv[5] );
Paul Bakker20a78082011-01-21 09:32:12 +0000185 goto exit;
186 }
Janos Follath8eb64132016-06-03 15:40:57 +0100187
188 if( mbedtls_md_setup( &md_ctx, md_info, 1 ) != 0 )
189 {
Janos Follath352dbe22016-06-07 10:29:05 +0100190 mbedtls_fprintf( stderr, "mbedtls_md_setup failed\n" );
Janos Follath8eb64132016-06-03 15:40:57 +0100191 goto exit;
192 }
Paul Bakker20a78082011-01-21 09:32:12 +0000193
194 /*
195 * Read the secret key and clean the command line.
196 */
197 if( ( fkey = fopen( argv[6], "rb" ) ) != NULL )
198 {
199 keylen = fread( key, 1, sizeof( key ), fkey );
200 fclose( fkey );
201 }
202 else
203 {
204 if( memcmp( argv[6], "hex:", 4 ) == 0 )
205 {
206 p = &argv[6][4];
207 keylen = 0;
208
209 while( sscanf( p, "%02X", &n ) > 0 &&
210 keylen < (int) sizeof( key ) )
211 {
212 key[keylen++] = (unsigned char) n;
213 p += 2;
214 }
215 }
216 else
217 {
218 keylen = strlen( argv[6] );
219
220 if( keylen > (int) sizeof( key ) )
221 keylen = (int) sizeof( key );
222
223 memcpy( key, argv[6], keylen );
224 }
225 }
226
227 memset( argv[6], 0, strlen( argv[6] ) );
228
Paul Bakkercce9d772011-11-18 14:26:47 +0000229#if defined(_WIN32_WCE)
230 filesize = fseek( fin, 0L, SEEK_END );
231#else
232#if defined(_WIN32)
Paul Bakker20a78082011-01-21 09:32:12 +0000233 /*
234 * Support large files (> 2Gb) on Win32
235 */
236 li_size.QuadPart = 0;
237 li_size.LowPart =
238 SetFilePointer( (HANDLE) _get_osfhandle( _fileno( fin ) ),
239 li_size.LowPart, &li_size.HighPart, FILE_END );
240
241 if( li_size.LowPart == 0xFFFFFFFF && GetLastError() != NO_ERROR )
242 {
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200243 mbedtls_fprintf( stderr, "SetFilePointer(0,FILE_END) failed\n" );
Paul Bakker20a78082011-01-21 09:32:12 +0000244 goto exit;
245 }
246
247 filesize = li_size.QuadPart;
248#else
249 if( ( filesize = lseek( fileno( fin ), 0, SEEK_END ) ) < 0 )
250 {
251 perror( "lseek" );
252 goto exit;
253 }
254#endif
Paul Bakkercce9d772011-11-18 14:26:47 +0000255#endif
Paul Bakker20a78082011-01-21 09:32:12 +0000256
257 if( fseek( fin, 0, SEEK_SET ) < 0 )
258 {
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200259 mbedtls_fprintf( stderr, "fseek(0,SEEK_SET) failed\n" );
Paul Bakker20a78082011-01-21 09:32:12 +0000260 goto exit;
261 }
262
263 if( mode == MODE_ENCRYPT )
264 {
265 /*
266 * Generate the initialization vector as:
267 * IV = SHA-256( filesize || filename )[0..15]
268 */
269 for( i = 0; i < 8; i++ )
270 buffer[i] = (unsigned char)( filesize >> ( i << 3 ) );
271
272 p = argv[2];
273
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200274 mbedtls_md_starts( &md_ctx );
275 mbedtls_md_update( &md_ctx, buffer, 8 );
276 mbedtls_md_update( &md_ctx, (unsigned char *) p, strlen( p ) );
277 mbedtls_md_finish( &md_ctx, digest );
Paul Bakker20a78082011-01-21 09:32:12 +0000278
279 memcpy( IV, digest, 16 );
280
281 /*
282 * The last four bits in the IV are actually used
283 * to store the file size modulo the AES block size.
284 */
285 lastn = (int)( filesize & 0x0F );
286
287 IV[15] = (unsigned char)
288 ( ( IV[15] & 0xF0 ) | lastn );
289
290 /*
291 * Append the IV at the beginning of the output.
292 */
293 if( fwrite( IV, 1, 16, fout ) != 16 )
294 {
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200295 mbedtls_fprintf( stderr, "fwrite(%d bytes) failed\n", 16 );
Paul Bakker20a78082011-01-21 09:32:12 +0000296 goto exit;
297 }
298
299 /*
300 * Hash the IV and the secret key together 8192 times
301 * using the result to setup the AES context and HMAC.
302 */
303 memset( digest, 0, 32 );
304 memcpy( digest, IV, 16 );
305
306 for( i = 0; i < 8192; i++ )
307 {
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200308 mbedtls_md_starts( &md_ctx );
309 mbedtls_md_update( &md_ctx, digest, 32 );
310 mbedtls_md_update( &md_ctx, key, keylen );
311 mbedtls_md_finish( &md_ctx, digest );
Paul Bakker20a78082011-01-21 09:32:12 +0000312
313 }
314
315 memset( key, 0, sizeof( key ) );
316
Manuel Pégourié-Gonnard898e0aa2015-06-18 15:28:12 +0200317 if( mbedtls_cipher_setkey( &cipher_ctx, digest, cipher_info->key_bitlen,
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200318 MBEDTLS_ENCRYPT ) != 0 )
Paul Bakker26c4e3c2012-07-04 17:08:33 +0000319 {
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200320 mbedtls_fprintf( stderr, "mbedtls_cipher_setkey() returned error\n");
Paul Bakker26c4e3c2012-07-04 17:08:33 +0000321 goto exit;
322 }
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200323 if( mbedtls_cipher_set_iv( &cipher_ctx, IV, 16 ) != 0 )
Manuel Pégourié-Gonnard9c853b92013-09-03 13:04:44 +0200324 {
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200325 mbedtls_fprintf( stderr, "mbedtls_cipher_set_iv() returned error\n");
Manuel Pégourié-Gonnard9c853b92013-09-03 13:04:44 +0200326 goto exit;
327 }
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200328 if( mbedtls_cipher_reset( &cipher_ctx ) != 0 )
Paul Bakker26c4e3c2012-07-04 17:08:33 +0000329 {
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200330 mbedtls_fprintf( stderr, "mbedtls_cipher_reset() returned error\n");
Paul Bakker26c4e3c2012-07-04 17:08:33 +0000331 goto exit;
332 }
Paul Bakker20a78082011-01-21 09:32:12 +0000333
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200334 mbedtls_md_hmac_starts( &md_ctx, digest, 32 );
Paul Bakker20a78082011-01-21 09:32:12 +0000335
336 /*
337 * Encrypt and write the ciphertext.
338 */
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200339 for( offset = 0; offset < filesize; offset += mbedtls_cipher_get_block_size( &cipher_ctx ) )
Paul Bakker20a78082011-01-21 09:32:12 +0000340 {
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200341 ilen = ( (unsigned int) filesize - offset > mbedtls_cipher_get_block_size( &cipher_ctx ) ) ?
342 mbedtls_cipher_get_block_size( &cipher_ctx ) : (unsigned int) ( filesize - offset );
Paul Bakker20a78082011-01-21 09:32:12 +0000343
Paul Bakker25b5fe52011-05-26 14:02:58 +0000344 if( fread( buffer, 1, ilen, fin ) != ilen )
Paul Bakker20a78082011-01-21 09:32:12 +0000345 {
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200346 mbedtls_fprintf( stderr, "fread(%ld bytes) failed\n", (long) ilen );
Paul Bakker20a78082011-01-21 09:32:12 +0000347 goto exit;
348 }
349
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200350 if( mbedtls_cipher_update( &cipher_ctx, buffer, ilen, output, &olen ) != 0 )
Paul Bakkercbe3d0d2014-04-17 16:00:59 +0200351 {
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200352 mbedtls_fprintf( stderr, "mbedtls_cipher_update() returned error\n");
Paul Bakkercbe3d0d2014-04-17 16:00:59 +0200353 goto exit;
354 }
355
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200356 mbedtls_md_hmac_update( &md_ctx, output, olen );
Paul Bakker20a78082011-01-21 09:32:12 +0000357
Paul Bakker2c0994e2011-05-25 13:51:57 +0000358 if( fwrite( output, 1, olen, fout ) != olen )
Paul Bakker20a78082011-01-21 09:32:12 +0000359 {
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200360 mbedtls_fprintf( stderr, "fwrite(%ld bytes) failed\n", (long) olen );
Paul Bakker20a78082011-01-21 09:32:12 +0000361 goto exit;
362 }
363 }
364
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200365 if( mbedtls_cipher_finish( &cipher_ctx, output, &olen ) != 0 )
Paul Bakker26c4e3c2012-07-04 17:08:33 +0000366 {
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200367 mbedtls_fprintf( stderr, "mbedtls_cipher_finish() returned error\n" );
Paul Bakker26c4e3c2012-07-04 17:08:33 +0000368 goto exit;
369 }
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200370 mbedtls_md_hmac_update( &md_ctx, output, olen );
Paul Bakker20a78082011-01-21 09:32:12 +0000371
Paul Bakker2c0994e2011-05-25 13:51:57 +0000372 if( fwrite( output, 1, olen, fout ) != olen )
Paul Bakker20a78082011-01-21 09:32:12 +0000373 {
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200374 mbedtls_fprintf( stderr, "fwrite(%ld bytes) failed\n", (long) olen );
Paul Bakker20a78082011-01-21 09:32:12 +0000375 goto exit;
376 }
Paul Bakker26c4e3c2012-07-04 17:08:33 +0000377
Paul Bakker20a78082011-01-21 09:32:12 +0000378 /*
379 * Finally write the HMAC.
380 */
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200381 mbedtls_md_hmac_finish( &md_ctx, digest );
Paul Bakker20a78082011-01-21 09:32:12 +0000382
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200383 if( fwrite( digest, 1, mbedtls_md_get_size( md_info ), fout ) != mbedtls_md_get_size( md_info ) )
Paul Bakker20a78082011-01-21 09:32:12 +0000384 {
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200385 mbedtls_fprintf( stderr, "fwrite(%d bytes) failed\n", mbedtls_md_get_size( md_info ) );
Paul Bakker20a78082011-01-21 09:32:12 +0000386 goto exit;
387 }
388 }
389
390 if( mode == MODE_DECRYPT )
391 {
392 /*
393 * The encrypted file must be structured as follows:
394 *
395 * 00 .. 15 Initialization Vector
396 * 16 .. 31 AES Encrypted Block #1
397 * ..
398 * N*16 .. (N+1)*16 - 1 AES Encrypted Block #N
399 * (N+1)*16 .. (N+1)*16 + 32 HMAC-SHA-256(ciphertext)
400 */
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200401 if( filesize < 16 + mbedtls_md_get_size( md_info ) )
Paul Bakker20a78082011-01-21 09:32:12 +0000402 {
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200403 mbedtls_fprintf( stderr, "File too short to be encrypted.\n" );
Paul Bakker20a78082011-01-21 09:32:12 +0000404 goto exit;
405 }
406
Janos Follath8eb64132016-06-03 15:40:57 +0100407 if( mbedtls_cipher_get_block_size( &cipher_ctx ) == 0 )
408 {
Janos Follath352dbe22016-06-07 10:29:05 +0100409 mbedtls_fprintf( stderr, "Invalid cipher block size: 0. \n" );
Janos Follath8eb64132016-06-03 15:40:57 +0100410 goto exit;
411 }
412
413 /*
414 * Check the file size.
415 */
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200416 if( ( ( filesize - mbedtls_md_get_size( md_info ) ) %
417 mbedtls_cipher_get_block_size( &cipher_ctx ) ) != 0 )
Paul Bakker20a78082011-01-21 09:32:12 +0000418 {
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200419 mbedtls_fprintf( stderr, "File content not a multiple of the block size (%d).\n",
420 mbedtls_cipher_get_block_size( &cipher_ctx ));
Paul Bakker20a78082011-01-21 09:32:12 +0000421 goto exit;
422 }
423
424 /*
Paul Bakker60b1d102013-10-29 10:02:51 +0100425 * Subtract the IV + HMAC length.
Paul Bakker20a78082011-01-21 09:32:12 +0000426 */
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200427 filesize -= ( 16 + mbedtls_md_get_size( md_info ) );
Paul Bakker20a78082011-01-21 09:32:12 +0000428
429 /*
430 * Read the IV and original filesize modulo 16.
431 */
432 if( fread( buffer, 1, 16, fin ) != 16 )
433 {
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200434 mbedtls_fprintf( stderr, "fread(%d bytes) failed\n", 16 );
Paul Bakker20a78082011-01-21 09:32:12 +0000435 goto exit;
436 }
437
438 memcpy( IV, buffer, 16 );
439 lastn = IV[15] & 0x0F;
440
441 /*
442 * Hash the IV and the secret key together 8192 times
443 * using the result to setup the AES context and HMAC.
444 */
445 memset( digest, 0, 32 );
446 memcpy( digest, IV, 16 );
447
448 for( i = 0; i < 8192; i++ )
449 {
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200450 mbedtls_md_starts( &md_ctx );
451 mbedtls_md_update( &md_ctx, digest, 32 );
452 mbedtls_md_update( &md_ctx, key, keylen );
453 mbedtls_md_finish( &md_ctx, digest );
Paul Bakker20a78082011-01-21 09:32:12 +0000454 }
455
456 memset( key, 0, sizeof( key ) );
457
Manuel Pégourié-Gonnard898e0aa2015-06-18 15:28:12 +0200458 if( mbedtls_cipher_setkey( &cipher_ctx, digest, cipher_info->key_bitlen,
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200459 MBEDTLS_DECRYPT ) != 0 )
Paul Bakkercbe3d0d2014-04-17 16:00:59 +0200460 {
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200461 mbedtls_fprintf( stderr, "mbedtls_cipher_setkey() returned error\n" );
Paul Bakkercbe3d0d2014-04-17 16:00:59 +0200462 goto exit;
463 }
464
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200465 if( mbedtls_cipher_set_iv( &cipher_ctx, IV, 16 ) != 0 )
Paul Bakkercbe3d0d2014-04-17 16:00:59 +0200466 {
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200467 mbedtls_fprintf( stderr, "mbedtls_cipher_set_iv() returned error\n" );
Paul Bakkercbe3d0d2014-04-17 16:00:59 +0200468 goto exit;
469 }
470
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200471 if( mbedtls_cipher_reset( &cipher_ctx ) != 0 )
Paul Bakkercbe3d0d2014-04-17 16:00:59 +0200472 {
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200473 mbedtls_fprintf( stderr, "mbedtls_cipher_reset() returned error\n" );
Paul Bakkercbe3d0d2014-04-17 16:00:59 +0200474 goto exit;
475 }
Paul Bakker20a78082011-01-21 09:32:12 +0000476
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200477 mbedtls_md_hmac_starts( &md_ctx, digest, 32 );
Paul Bakker20a78082011-01-21 09:32:12 +0000478
479 /*
480 * Decrypt and write the plaintext.
481 */
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200482 for( offset = 0; offset < filesize; offset += mbedtls_cipher_get_block_size( &cipher_ctx ) )
Paul Bakker20a78082011-01-21 09:32:12 +0000483 {
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200484 if( fread( buffer, 1, mbedtls_cipher_get_block_size( &cipher_ctx ), fin ) !=
485 (size_t) mbedtls_cipher_get_block_size( &cipher_ctx ) )
Paul Bakker20a78082011-01-21 09:32:12 +0000486 {
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200487 mbedtls_fprintf( stderr, "fread(%d bytes) failed\n",
488 mbedtls_cipher_get_block_size( &cipher_ctx ) );
Paul Bakker20a78082011-01-21 09:32:12 +0000489 goto exit;
490 }
491
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200492 mbedtls_md_hmac_update( &md_ctx, buffer, mbedtls_cipher_get_block_size( &cipher_ctx ) );
493 if( mbedtls_cipher_update( &cipher_ctx, buffer,
494 mbedtls_cipher_get_block_size( &cipher_ctx ),
Paul Bakkercbe3d0d2014-04-17 16:00:59 +0200495 output, &olen ) != 0 )
496 {
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200497 mbedtls_fprintf( stderr, "mbedtls_cipher_update() returned error\n" );
Paul Bakkercbe3d0d2014-04-17 16:00:59 +0200498 goto exit;
499 }
Paul Bakker20a78082011-01-21 09:32:12 +0000500
Paul Bakker2c0994e2011-05-25 13:51:57 +0000501 if( fwrite( output, 1, olen, fout ) != olen )
Paul Bakker20a78082011-01-21 09:32:12 +0000502 {
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200503 mbedtls_fprintf( stderr, "fwrite(%ld bytes) failed\n", (long) olen );
Paul Bakker20a78082011-01-21 09:32:12 +0000504 goto exit;
505 }
506 }
507
508 /*
Paul Bakker20a78082011-01-21 09:32:12 +0000509 * Verify the message authentication code.
510 */
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200511 mbedtls_md_hmac_finish( &md_ctx, digest );
Paul Bakker20a78082011-01-21 09:32:12 +0000512
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200513 if( fread( buffer, 1, mbedtls_md_get_size( md_info ), fin ) != mbedtls_md_get_size( md_info ) )
Paul Bakker20a78082011-01-21 09:32:12 +0000514 {
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200515 mbedtls_fprintf( stderr, "fread(%d bytes) failed\n", mbedtls_md_get_size( md_info ) );
Paul Bakker20a78082011-01-21 09:32:12 +0000516 goto exit;
517 }
518
Paul Bakker424cd692013-10-31 14:22:08 +0100519 /* Use constant-time buffer comparison */
520 diff = 0;
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200521 for( i = 0; i < mbedtls_md_get_size( md_info ); i++ )
Paul Bakker424cd692013-10-31 14:22:08 +0100522 diff |= digest[i] ^ buffer[i];
523
524 if( diff != 0 )
Paul Bakker20a78082011-01-21 09:32:12 +0000525 {
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200526 mbedtls_fprintf( stderr, "HMAC check failed: wrong key, "
Paul Bakker20a78082011-01-21 09:32:12 +0000527 "or file corrupted.\n" );
528 goto exit;
529 }
Manuel Pégourié-Gonnard0f2eacb2013-11-25 17:55:17 +0100530
531 /*
532 * Write the final block of data
533 */
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200534 mbedtls_cipher_finish( &cipher_ctx, output, &olen );
Manuel Pégourié-Gonnard0f2eacb2013-11-25 17:55:17 +0100535
536 if( fwrite( output, 1, olen, fout ) != olen )
537 {
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200538 mbedtls_fprintf( stderr, "fwrite(%ld bytes) failed\n", (long) olen );
Manuel Pégourié-Gonnard0f2eacb2013-11-25 17:55:17 +0100539 goto exit;
540 }
Paul Bakker20a78082011-01-21 09:32:12 +0000541 }
542
543 ret = 0;
544
545exit:
Paul Bakker6d440322011-02-06 12:49:19 +0000546 if( fin )
547 fclose( fin );
548 if( fout )
549 fclose( fout );
Paul Bakker20a78082011-01-21 09:32:12 +0000550
551 memset( buffer, 0, sizeof( buffer ) );
552 memset( digest, 0, sizeof( digest ) );
553
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200554 mbedtls_cipher_free( &cipher_ctx );
555 mbedtls_md_free( &md_ctx );
Paul Bakker20a78082011-01-21 09:32:12 +0000556
557 return( ret );
558}
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200559#endif /* MBEDTLS_CIPHER_C && MBEDTLS_MD_C && MBEDTLS_FS_IO */