source: azure_iot_hub_mbedtls/trunk/mbedtls-2.16.1/library/pem.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 * Privacy Enhanced Mail (PEM) decoding
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#if !defined(MBEDTLS_CONFIG_FILE)
23#include "mbedtls/config.h"
24#else
25#include MBEDTLS_CONFIG_FILE
26#endif
27
28#if defined(MBEDTLS_PEM_PARSE_C) || defined(MBEDTLS_PEM_WRITE_C)
29
30#include "mbedtls/pem.h"
31#include "mbedtls/base64.h"
32#include "mbedtls/des.h"
33#include "mbedtls/aes.h"
34#include "mbedtls/md5.h"
35#include "mbedtls/cipher.h"
36#include "mbedtls/platform_util.h"
37
38#include <string.h>
39
40#if defined(MBEDTLS_PLATFORM_C)
41#include "mbedtls/platform.h"
42#else
43#include <stdlib.h>
44#define mbedtls_calloc calloc
45#define mbedtls_free free
46#endif
47
48#if defined(MBEDTLS_PEM_PARSE_C)
49void mbedtls_pem_init( mbedtls_pem_context *ctx )
50{
51 memset( ctx, 0, sizeof( mbedtls_pem_context ) );
52}
53
54#if defined(MBEDTLS_MD5_C) && defined(MBEDTLS_CIPHER_MODE_CBC) && \
55 ( defined(MBEDTLS_DES_C) || defined(MBEDTLS_AES_C) )
56/*
57 * Read a 16-byte hex string and convert it to binary
58 */
59static int pem_get_iv( const unsigned char *s, unsigned char *iv,
60 size_t iv_len )
61{
62 size_t i, j, k;
63
64 memset( iv, 0, iv_len );
65
66 for( i = 0; i < iv_len * 2; i++, s++ )
67 {
68 if( *s >= '0' && *s <= '9' ) j = *s - '0'; else
69 if( *s >= 'A' && *s <= 'F' ) j = *s - '7'; else
70 if( *s >= 'a' && *s <= 'f' ) j = *s - 'W'; else
71 return( MBEDTLS_ERR_PEM_INVALID_ENC_IV );
72
73 k = ( ( i & 1 ) != 0 ) ? j : j << 4;
74
75 iv[i >> 1] = (unsigned char)( iv[i >> 1] | k );
76 }
77
78 return( 0 );
79}
80
81static int pem_pbkdf1( unsigned char *key, size_t keylen,
82 unsigned char *iv,
83 const unsigned char *pwd, size_t pwdlen )
84{
85 mbedtls_md5_context md5_ctx;
86 unsigned char md5sum[16];
87 size_t use_len;
88 int ret;
89
90 mbedtls_md5_init( &md5_ctx );
91
92 /*
93 * key[ 0..15] = MD5(pwd || IV)
94 */
95 if( ( ret = mbedtls_md5_starts_ret( &md5_ctx ) ) != 0 )
96 goto exit;
97 if( ( ret = mbedtls_md5_update_ret( &md5_ctx, pwd, pwdlen ) ) != 0 )
98 goto exit;
99 if( ( ret = mbedtls_md5_update_ret( &md5_ctx, iv, 8 ) ) != 0 )
100 goto exit;
101 if( ( ret = mbedtls_md5_finish_ret( &md5_ctx, md5sum ) ) != 0 )
102 goto exit;
103
104 if( keylen <= 16 )
105 {
106 memcpy( key, md5sum, keylen );
107 goto exit;
108 }
109
110 memcpy( key, md5sum, 16 );
111
112 /*
113 * key[16..23] = MD5(key[ 0..15] || pwd || IV])
114 */
115 if( ( ret = mbedtls_md5_starts_ret( &md5_ctx ) ) != 0 )
116 goto exit;
117 if( ( ret = mbedtls_md5_update_ret( &md5_ctx, md5sum, 16 ) ) != 0 )
118 goto exit;
119 if( ( ret = mbedtls_md5_update_ret( &md5_ctx, pwd, pwdlen ) ) != 0 )
120 goto exit;
121 if( ( ret = mbedtls_md5_update_ret( &md5_ctx, iv, 8 ) ) != 0 )
122 goto exit;
123 if( ( ret = mbedtls_md5_finish_ret( &md5_ctx, md5sum ) ) != 0 )
124 goto exit;
125
126 use_len = 16;
127 if( keylen < 32 )
128 use_len = keylen - 16;
129
130 memcpy( key + 16, md5sum, use_len );
131
132exit:
133 mbedtls_md5_free( &md5_ctx );
134 mbedtls_platform_zeroize( md5sum, 16 );
135
136 return( ret );
137}
138
139#if defined(MBEDTLS_DES_C)
140/*
141 * Decrypt with DES-CBC, using PBKDF1 for key derivation
142 */
143static int pem_des_decrypt( unsigned char des_iv[8],
144 unsigned char *buf, size_t buflen,
145 const unsigned char *pwd, size_t pwdlen )
146{
147 mbedtls_des_context des_ctx;
148 unsigned char des_key[8];
149 int ret;
150
151 mbedtls_des_init( &des_ctx );
152
153 if( ( ret = pem_pbkdf1( des_key, 8, des_iv, pwd, pwdlen ) ) != 0 )
154 goto exit;
155
156 if( ( ret = mbedtls_des_setkey_dec( &des_ctx, des_key ) ) != 0 )
157 goto exit;
158 ret = mbedtls_des_crypt_cbc( &des_ctx, MBEDTLS_DES_DECRYPT, buflen,
159 des_iv, buf, buf );
160
161exit:
162 mbedtls_des_free( &des_ctx );
163 mbedtls_platform_zeroize( des_key, 8 );
164
165 return( ret );
166}
167
168/*
169 * Decrypt with 3DES-CBC, using PBKDF1 for key derivation
170 */
171static int pem_des3_decrypt( unsigned char des3_iv[8],
172 unsigned char *buf, size_t buflen,
173 const unsigned char *pwd, size_t pwdlen )
174{
175 mbedtls_des3_context des3_ctx;
176 unsigned char des3_key[24];
177 int ret;
178
179 mbedtls_des3_init( &des3_ctx );
180
181 if( ( ret = pem_pbkdf1( des3_key, 24, des3_iv, pwd, pwdlen ) ) != 0 )
182 goto exit;
183
184 if( ( ret = mbedtls_des3_set3key_dec( &des3_ctx, des3_key ) ) != 0 )
185 goto exit;
186 ret = mbedtls_des3_crypt_cbc( &des3_ctx, MBEDTLS_DES_DECRYPT, buflen,
187 des3_iv, buf, buf );
188
189exit:
190 mbedtls_des3_free( &des3_ctx );
191 mbedtls_platform_zeroize( des3_key, 24 );
192
193 return( ret );
194}
195#endif /* MBEDTLS_DES_C */
196
197#if defined(MBEDTLS_AES_C)
198/*
199 * Decrypt with AES-XXX-CBC, using PBKDF1 for key derivation
200 */
201static int pem_aes_decrypt( unsigned char aes_iv[16], unsigned int keylen,
202 unsigned char *buf, size_t buflen,
203 const unsigned char *pwd, size_t pwdlen )
204{
205 mbedtls_aes_context aes_ctx;
206 unsigned char aes_key[32];
207 int ret;
208
209 mbedtls_aes_init( &aes_ctx );
210
211 if( ( ret = pem_pbkdf1( aes_key, keylen, aes_iv, pwd, pwdlen ) ) != 0 )
212 goto exit;
213
214 if( ( ret = mbedtls_aes_setkey_dec( &aes_ctx, aes_key, keylen * 8 ) ) != 0 )
215 goto exit;
216 ret = mbedtls_aes_crypt_cbc( &aes_ctx, MBEDTLS_AES_DECRYPT, buflen,
217 aes_iv, buf, buf );
218
219exit:
220 mbedtls_aes_free( &aes_ctx );
221 mbedtls_platform_zeroize( aes_key, keylen );
222
223 return( ret );
224}
225#endif /* MBEDTLS_AES_C */
226
227#endif /* MBEDTLS_MD5_C && MBEDTLS_CIPHER_MODE_CBC &&
228 ( MBEDTLS_AES_C || MBEDTLS_DES_C ) */
229
230int mbedtls_pem_read_buffer( mbedtls_pem_context *ctx, const char *header, const char *footer,
231 const unsigned char *data, const unsigned char *pwd,
232 size_t pwdlen, size_t *use_len )
233{
234 int ret, enc;
235 size_t len;
236 unsigned char *buf;
237 const unsigned char *s1, *s2, *end;
238#if defined(MBEDTLS_MD5_C) && defined(MBEDTLS_CIPHER_MODE_CBC) && \
239 ( defined(MBEDTLS_DES_C) || defined(MBEDTLS_AES_C) )
240 unsigned char pem_iv[16];
241 mbedtls_cipher_type_t enc_alg = MBEDTLS_CIPHER_NONE;
242#else
243 ((void) pwd);
244 ((void) pwdlen);
245#endif /* MBEDTLS_MD5_C && MBEDTLS_CIPHER_MODE_CBC &&
246 ( MBEDTLS_AES_C || MBEDTLS_DES_C ) */
247
248 if( ctx == NULL )
249 return( MBEDTLS_ERR_PEM_BAD_INPUT_DATA );
250
251 s1 = (unsigned char *) strstr( (const char *) data, header );
252
253 if( s1 == NULL )
254 return( MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT );
255
256 s2 = (unsigned char *) strstr( (const char *) data, footer );
257
258 if( s2 == NULL || s2 <= s1 )
259 return( MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT );
260
261 s1 += strlen( header );
262 if( *s1 == ' ' ) s1++;
263 if( *s1 == '\r' ) s1++;
264 if( *s1 == '\n' ) s1++;
265 else return( MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT );
266
267 end = s2;
268 end += strlen( footer );
269 if( *end == ' ' ) end++;
270 if( *end == '\r' ) end++;
271 if( *end == '\n' ) end++;
272 *use_len = end - data;
273
274 enc = 0;
275
276 if( s2 - s1 >= 22 && memcmp( s1, "Proc-Type: 4,ENCRYPTED", 22 ) == 0 )
277 {
278#if defined(MBEDTLS_MD5_C) && defined(MBEDTLS_CIPHER_MODE_CBC) && \
279 ( defined(MBEDTLS_DES_C) || defined(MBEDTLS_AES_C) )
280 enc++;
281
282 s1 += 22;
283 if( *s1 == '\r' ) s1++;
284 if( *s1 == '\n' ) s1++;
285 else return( MBEDTLS_ERR_PEM_INVALID_DATA );
286
287
288#if defined(MBEDTLS_DES_C)
289 if( s2 - s1 >= 23 && memcmp( s1, "DEK-Info: DES-EDE3-CBC,", 23 ) == 0 )
290 {
291 enc_alg = MBEDTLS_CIPHER_DES_EDE3_CBC;
292
293 s1 += 23;
294 if( s2 - s1 < 16 || pem_get_iv( s1, pem_iv, 8 ) != 0 )
295 return( MBEDTLS_ERR_PEM_INVALID_ENC_IV );
296
297 s1 += 16;
298 }
299 else if( s2 - s1 >= 18 && memcmp( s1, "DEK-Info: DES-CBC,", 18 ) == 0 )
300 {
301 enc_alg = MBEDTLS_CIPHER_DES_CBC;
302
303 s1 += 18;
304 if( s2 - s1 < 16 || pem_get_iv( s1, pem_iv, 8) != 0 )
305 return( MBEDTLS_ERR_PEM_INVALID_ENC_IV );
306
307 s1 += 16;
308 }
309#endif /* MBEDTLS_DES_C */
310
311#if defined(MBEDTLS_AES_C)
312 if( s2 - s1 >= 14 && memcmp( s1, "DEK-Info: AES-", 14 ) == 0 )
313 {
314 if( s2 - s1 < 22 )
315 return( MBEDTLS_ERR_PEM_UNKNOWN_ENC_ALG );
316 else if( memcmp( s1, "DEK-Info: AES-128-CBC,", 22 ) == 0 )
317 enc_alg = MBEDTLS_CIPHER_AES_128_CBC;
318 else if( memcmp( s1, "DEK-Info: AES-192-CBC,", 22 ) == 0 )
319 enc_alg = MBEDTLS_CIPHER_AES_192_CBC;
320 else if( memcmp( s1, "DEK-Info: AES-256-CBC,", 22 ) == 0 )
321 enc_alg = MBEDTLS_CIPHER_AES_256_CBC;
322 else
323 return( MBEDTLS_ERR_PEM_UNKNOWN_ENC_ALG );
324
325 s1 += 22;
326 if( s2 - s1 < 32 || pem_get_iv( s1, pem_iv, 16 ) != 0 )
327 return( MBEDTLS_ERR_PEM_INVALID_ENC_IV );
328
329 s1 += 32;
330 }
331#endif /* MBEDTLS_AES_C */
332
333 if( enc_alg == MBEDTLS_CIPHER_NONE )
334 return( MBEDTLS_ERR_PEM_UNKNOWN_ENC_ALG );
335
336 if( *s1 == '\r' ) s1++;
337 if( *s1 == '\n' ) s1++;
338 else return( MBEDTLS_ERR_PEM_INVALID_DATA );
339#else
340 return( MBEDTLS_ERR_PEM_FEATURE_UNAVAILABLE );
341#endif /* MBEDTLS_MD5_C && MBEDTLS_CIPHER_MODE_CBC &&
342 ( MBEDTLS_AES_C || MBEDTLS_DES_C ) */
343 }
344
345 if( s1 >= s2 )
346 return( MBEDTLS_ERR_PEM_INVALID_DATA );
347
348 ret = mbedtls_base64_decode( NULL, 0, &len, s1, s2 - s1 );
349
350 if( ret == MBEDTLS_ERR_BASE64_INVALID_CHARACTER )
351 return( MBEDTLS_ERR_PEM_INVALID_DATA + ret );
352
353 if( ( buf = mbedtls_calloc( 1, len ) ) == NULL )
354 return( MBEDTLS_ERR_PEM_ALLOC_FAILED );
355
356 if( ( ret = mbedtls_base64_decode( buf, len, &len, s1, s2 - s1 ) ) != 0 )
357 {
358 mbedtls_platform_zeroize( buf, len );
359 mbedtls_free( buf );
360 return( MBEDTLS_ERR_PEM_INVALID_DATA + ret );
361 }
362
363 if( enc != 0 )
364 {
365#if defined(MBEDTLS_MD5_C) && defined(MBEDTLS_CIPHER_MODE_CBC) && \
366 ( defined(MBEDTLS_DES_C) || defined(MBEDTLS_AES_C) )
367 if( pwd == NULL )
368 {
369 mbedtls_platform_zeroize( buf, len );
370 mbedtls_free( buf );
371 return( MBEDTLS_ERR_PEM_PASSWORD_REQUIRED );
372 }
373
374 ret = 0;
375
376#if defined(MBEDTLS_DES_C)
377 if( enc_alg == MBEDTLS_CIPHER_DES_EDE3_CBC )
378 ret = pem_des3_decrypt( pem_iv, buf, len, pwd, pwdlen );
379 else if( enc_alg == MBEDTLS_CIPHER_DES_CBC )
380 ret = pem_des_decrypt( pem_iv, buf, len, pwd, pwdlen );
381#endif /* MBEDTLS_DES_C */
382
383#if defined(MBEDTLS_AES_C)
384 if( enc_alg == MBEDTLS_CIPHER_AES_128_CBC )
385 ret = pem_aes_decrypt( pem_iv, 16, buf, len, pwd, pwdlen );
386 else if( enc_alg == MBEDTLS_CIPHER_AES_192_CBC )
387 ret = pem_aes_decrypt( pem_iv, 24, buf, len, pwd, pwdlen );
388 else if( enc_alg == MBEDTLS_CIPHER_AES_256_CBC )
389 ret = pem_aes_decrypt( pem_iv, 32, buf, len, pwd, pwdlen );
390#endif /* MBEDTLS_AES_C */
391
392 if( ret != 0 )
393 {
394 mbedtls_free( buf );
395 return( ret );
396 }
397
398 /*
399 * The result will be ASN.1 starting with a SEQUENCE tag, with 1 to 3
400 * length bytes (allow 4 to be sure) in all known use cases.
401 *
402 * Use that as a heuristic to try to detect password mismatches.
403 */
404 if( len <= 2 || buf[0] != 0x30 || buf[1] > 0x83 )
405 {
406 mbedtls_platform_zeroize( buf, len );
407 mbedtls_free( buf );
408 return( MBEDTLS_ERR_PEM_PASSWORD_MISMATCH );
409 }
410#else
411 mbedtls_platform_zeroize( buf, len );
412 mbedtls_free( buf );
413 return( MBEDTLS_ERR_PEM_FEATURE_UNAVAILABLE );
414#endif /* MBEDTLS_MD5_C && MBEDTLS_CIPHER_MODE_CBC &&
415 ( MBEDTLS_AES_C || MBEDTLS_DES_C ) */
416 }
417
418 ctx->buf = buf;
419 ctx->buflen = len;
420
421 return( 0 );
422}
423
424void mbedtls_pem_free( mbedtls_pem_context *ctx )
425{
426 if ( ctx->buf != NULL )
427 {
428 mbedtls_platform_zeroize( ctx->buf, ctx->buflen );
429 mbedtls_free( ctx->buf );
430 }
431 mbedtls_free( ctx->info );
432
433 mbedtls_platform_zeroize( ctx, sizeof( mbedtls_pem_context ) );
434}
435#endif /* MBEDTLS_PEM_PARSE_C */
436
437#if defined(MBEDTLS_PEM_WRITE_C)
438int mbedtls_pem_write_buffer( const char *header, const char *footer,
439 const unsigned char *der_data, size_t der_len,
440 unsigned char *buf, size_t buf_len, size_t *olen )
441{
442 int ret;
443 unsigned char *encode_buf = NULL, *c, *p = buf;
444 size_t len = 0, use_len, add_len = 0;
445
446 mbedtls_base64_encode( NULL, 0, &use_len, der_data, der_len );
447 add_len = strlen( header ) + strlen( footer ) + ( use_len / 64 ) + 1;
448
449 if( use_len + add_len > buf_len )
450 {
451 *olen = use_len + add_len;
452 return( MBEDTLS_ERR_BASE64_BUFFER_TOO_SMALL );
453 }
454
455 if( use_len != 0 &&
456 ( ( encode_buf = mbedtls_calloc( 1, use_len ) ) == NULL ) )
457 return( MBEDTLS_ERR_PEM_ALLOC_FAILED );
458
459 if( ( ret = mbedtls_base64_encode( encode_buf, use_len, &use_len, der_data,
460 der_len ) ) != 0 )
461 {
462 mbedtls_free( encode_buf );
463 return( ret );
464 }
465
466 memcpy( p, header, strlen( header ) );
467 p += strlen( header );
468 c = encode_buf;
469
470 while( use_len )
471 {
472 len = ( use_len > 64 ) ? 64 : use_len;
473 memcpy( p, c, len );
474 use_len -= len;
475 p += len;
476 c += len;
477 *p++ = '\n';
478 }
479
480 memcpy( p, footer, strlen( footer ) );
481 p += strlen( footer );
482
483 *p++ = '\0';
484 *olen = p - buf;
485
486 mbedtls_free( encode_buf );
487 return( 0 );
488}
489#endif /* MBEDTLS_PEM_WRITE_C */
490#endif /* MBEDTLS_PEM_PARSE_C || MBEDTLS_PEM_WRITE_C */
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