1 /*
2 * Diffie-Hellman-Merkle key exchange
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 * The following sources were referenced in the design of this implementation
23 * of the Diffie-Hellman-Merkle algorithm:
24 *
25 * [1] Handbook of Applied Cryptography - 1997, Chapter 12
26 * Menezes, van Oorschot and Vanstone
27 *
28 */
29
30 #if !defined(MBEDTLS_CONFIG_FILE)
31 #include "mbedtls/config.h"
32 #else
33 #include MBEDTLS_CONFIG_FILE
34 #endif
35
36 #if defined(MBEDTLS_DHM_C)
37
38 #include "mbedtls/dhm.h"
39 #include "mbedtls/platform_util.h"
40
41 #include <string.h>
42
43 #if defined(MBEDTLS_PEM_PARSE_C)
44 #include "mbedtls/pem.h"
45 #endif
46
47 #if defined(MBEDTLS_ASN1_PARSE_C)
48 #include "mbedtls/asn1.h"
49 #endif
50
51 #if defined(MBEDTLS_PLATFORM_C)
52 #include "mbedtls/platform.h"
53 #else
54 #include <stdlib.h>
55 #include <stdio.h>
56 #define mbedtls_printf printf
57 #define mbedtls_calloc calloc
58 #define mbedtls_free free
59 #endif
60
61 #if !defined(MBEDTLS_DHM_ALT)
62
63 #define DHM_VALIDATE_RET( cond ) \
64 MBEDTLS_INTERNAL_VALIDATE_RET( cond, MBEDTLS_ERR_DHM_BAD_INPUT_DATA )
65 #define DHM_VALIDATE( cond ) \
66 MBEDTLS_INTERNAL_VALIDATE( cond )
67
68 /*
69 * helper to validate the mbedtls_mpi size and import it
70 */
dhm_read_bignum(mbedtls_mpi * X,unsigned char ** p,const unsigned char * end)71 static int dhm_read_bignum( mbedtls_mpi *X,
72 unsigned char **p,
73 const unsigned char *end )
74 {
75 int ret, n;
76
77 if( end - *p < 2 )
78 return( MBEDTLS_ERR_DHM_BAD_INPUT_DATA );
79
80 n = ( (*p)[0] << 8 ) | (*p)[1];
81 (*p) += 2;
82
83 if( (int)( end - *p ) < n )
84 return( MBEDTLS_ERR_DHM_BAD_INPUT_DATA );
85
86 if( ( ret = mbedtls_mpi_read_binary( X, *p, n ) ) != 0 )
87 return( MBEDTLS_ERR_DHM_READ_PARAMS_FAILED + ret );
88
89 (*p) += n;
90
91 return( 0 );
92 }
93
94 /*
95 * Verify sanity of parameter with regards to P
96 *
97 * Parameter should be: 2 <= public_param <= P - 2
98 *
99 * This means that we need to return an error if
100 * public_param < 2 or public_param > P-2
101 *
102 * For more information on the attack, see:
103 * http://www.cl.cam.ac.uk/~rja14/Papers/psandqs.pdf
104 * http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2005-2643
105 */
dhm_check_range(const mbedtls_mpi * param,const mbedtls_mpi * P)106 static int dhm_check_range( const mbedtls_mpi *param, const mbedtls_mpi *P )
107 {
108 mbedtls_mpi L, U;
109 int ret = 0;
110
111 mbedtls_mpi_init( &L ); mbedtls_mpi_init( &U );
112
113 MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &L, 2 ) );
114 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &U, P, 2 ) );
115
116 if( mbedtls_mpi_cmp_mpi( param, &L ) < 0 ||
117 mbedtls_mpi_cmp_mpi( param, &U ) > 0 )
118 {
119 ret = MBEDTLS_ERR_DHM_BAD_INPUT_DATA;
120 }
121
122 cleanup:
123 mbedtls_mpi_free( &L ); mbedtls_mpi_free( &U );
124 return( ret );
125 }
126
mbedtls_dhm_init(mbedtls_dhm_context * ctx)127 void mbedtls_dhm_init( mbedtls_dhm_context *ctx )
128 {
129 DHM_VALIDATE( ctx != NULL );
130 memset( ctx, 0, sizeof( mbedtls_dhm_context ) );
131 }
132
133 /*
134 * Parse the ServerKeyExchange parameters
135 */
mbedtls_dhm_read_params(mbedtls_dhm_context * ctx,unsigned char ** p,const unsigned char * end)136 int mbedtls_dhm_read_params( mbedtls_dhm_context *ctx,
137 unsigned char **p,
138 const unsigned char *end )
139 {
140 int ret;
141 DHM_VALIDATE_RET( ctx != NULL );
142 DHM_VALIDATE_RET( p != NULL && *p != NULL );
143 DHM_VALIDATE_RET( end != NULL );
144
145 if( ( ret = dhm_read_bignum( &ctx->P, p, end ) ) != 0 ||
146 ( ret = dhm_read_bignum( &ctx->G, p, end ) ) != 0 ||
147 ( ret = dhm_read_bignum( &ctx->GY, p, end ) ) != 0 )
148 return( ret );
149
150 if( ( ret = dhm_check_range( &ctx->GY, &ctx->P ) ) != 0 )
151 return( ret );
152
153 ctx->len = mbedtls_mpi_size( &ctx->P );
154
155 return( 0 );
156 }
157
158 /*
159 * Setup and write the ServerKeyExchange parameters
160 */
mbedtls_dhm_make_params(mbedtls_dhm_context * ctx,int x_size,unsigned char * output,size_t * olen,int (* f_rng)(void *,unsigned char *,size_t),void * p_rng)161 int mbedtls_dhm_make_params( mbedtls_dhm_context *ctx, int x_size,
162 unsigned char *output, size_t *olen,
163 int (*f_rng)(void *, unsigned char *, size_t),
164 void *p_rng )
165 {
166 int ret, count = 0;
167 size_t n1, n2, n3;
168 unsigned char *p;
169 DHM_VALIDATE_RET( ctx != NULL );
170 DHM_VALIDATE_RET( output != NULL );
171 DHM_VALIDATE_RET( olen != NULL );
172 DHM_VALIDATE_RET( f_rng != NULL );
173
174 if( mbedtls_mpi_cmp_int( &ctx->P, 0 ) == 0 )
175 return( MBEDTLS_ERR_DHM_BAD_INPUT_DATA );
176
177 /*
178 * Generate X as large as possible ( < P )
179 */
180 do
181 {
182 MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( &ctx->X, x_size, f_rng, p_rng ) );
183
184 while( mbedtls_mpi_cmp_mpi( &ctx->X, &ctx->P ) >= 0 )
185 MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &ctx->X, 1 ) );
186
187 if( count++ > 10 )
188 return( MBEDTLS_ERR_DHM_MAKE_PARAMS_FAILED );
189 }
190 while( dhm_check_range( &ctx->X, &ctx->P ) != 0 );
191
192 /*
193 * Calculate GX = G^X mod P
194 */
195 MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &ctx->GX, &ctx->G, &ctx->X,
196 &ctx->P , &ctx->RP ) );
197
198 if( ( ret = dhm_check_range( &ctx->GX, &ctx->P ) ) != 0 )
199 return( ret );
200
201 /*
202 * export P, G, GX
203 */
204 #define DHM_MPI_EXPORT( X, n ) \
205 do { \
206 MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( ( X ), \
207 p + 2, \
208 ( n ) ) ); \
209 *p++ = (unsigned char)( ( n ) >> 8 ); \
210 *p++ = (unsigned char)( ( n ) ); \
211 p += ( n ); \
212 } while( 0 )
213
214 n1 = mbedtls_mpi_size( &ctx->P );
215 n2 = mbedtls_mpi_size( &ctx->G );
216 n3 = mbedtls_mpi_size( &ctx->GX );
217
218 p = output;
219 DHM_MPI_EXPORT( &ctx->P , n1 );
220 DHM_MPI_EXPORT( &ctx->G , n2 );
221 DHM_MPI_EXPORT( &ctx->GX, n3 );
222
223 *olen = p - output;
224
225 ctx->len = n1;
226
227 cleanup:
228
229 if( ret != 0 )
230 return( MBEDTLS_ERR_DHM_MAKE_PARAMS_FAILED + ret );
231
232 return( 0 );
233 }
234
235 /*
236 * Set prime modulus and generator
237 */
mbedtls_dhm_set_group(mbedtls_dhm_context * ctx,const mbedtls_mpi * P,const mbedtls_mpi * G)238 int mbedtls_dhm_set_group( mbedtls_dhm_context *ctx,
239 const mbedtls_mpi *P,
240 const mbedtls_mpi *G )
241 {
242 int ret;
243 DHM_VALIDATE_RET( ctx != NULL );
244 DHM_VALIDATE_RET( P != NULL );
245 DHM_VALIDATE_RET( G != NULL );
246
247 if( ( ret = mbedtls_mpi_copy( &ctx->P, P ) ) != 0 ||
248 ( ret = mbedtls_mpi_copy( &ctx->G, G ) ) != 0 )
249 {
250 return( MBEDTLS_ERR_DHM_SET_GROUP_FAILED + ret );
251 }
252
253 ctx->len = mbedtls_mpi_size( &ctx->P );
254 return( 0 );
255 }
256
257 /*
258 * Import the peer's public value G^Y
259 */
mbedtls_dhm_read_public(mbedtls_dhm_context * ctx,const unsigned char * input,size_t ilen)260 int mbedtls_dhm_read_public( mbedtls_dhm_context *ctx,
261 const unsigned char *input, size_t ilen )
262 {
263 int ret;
264 DHM_VALIDATE_RET( ctx != NULL );
265 DHM_VALIDATE_RET( input != NULL );
266
267 if( ilen < 1 || ilen > ctx->len )
268 return( MBEDTLS_ERR_DHM_BAD_INPUT_DATA );
269
270 if( ( ret = mbedtls_mpi_read_binary( &ctx->GY, input, ilen ) ) != 0 )
271 return( MBEDTLS_ERR_DHM_READ_PUBLIC_FAILED + ret );
272
273 return( 0 );
274 }
275
276 /*
277 * Create own private value X and export G^X
278 */
mbedtls_dhm_make_public(mbedtls_dhm_context * ctx,int x_size,unsigned char * output,size_t olen,int (* f_rng)(void *,unsigned char *,size_t),void * p_rng)279 int mbedtls_dhm_make_public( mbedtls_dhm_context *ctx, int x_size,
280 unsigned char *output, size_t olen,
281 int (*f_rng)(void *, unsigned char *, size_t),
282 void *p_rng )
283 {
284 int ret, count = 0;
285 DHM_VALIDATE_RET( ctx != NULL );
286 DHM_VALIDATE_RET( output != NULL );
287 DHM_VALIDATE_RET( f_rng != NULL );
288
289 if( olen < 1 || olen > ctx->len )
290 return( MBEDTLS_ERR_DHM_BAD_INPUT_DATA );
291
292 if( mbedtls_mpi_cmp_int( &ctx->P, 0 ) == 0 )
293 return( MBEDTLS_ERR_DHM_BAD_INPUT_DATA );
294
295 /*
296 * generate X and calculate GX = G^X mod P
297 */
298 do
299 {
300 MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( &ctx->X, x_size, f_rng, p_rng ) );
301
302 while( mbedtls_mpi_cmp_mpi( &ctx->X, &ctx->P ) >= 0 )
303 MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &ctx->X, 1 ) );
304
305 if( count++ > 10 )
306 return( MBEDTLS_ERR_DHM_MAKE_PUBLIC_FAILED );
307 }
308 while( dhm_check_range( &ctx->X, &ctx->P ) != 0 );
309
310 MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &ctx->GX, &ctx->G, &ctx->X,
311 &ctx->P , &ctx->RP ) );
312
313 if( ( ret = dhm_check_range( &ctx->GX, &ctx->P ) ) != 0 )
314 return( ret );
315
316 MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &ctx->GX, output, olen ) );
317
318 cleanup:
319
320 if( ret != 0 )
321 return( MBEDTLS_ERR_DHM_MAKE_PUBLIC_FAILED + ret );
322
323 return( 0 );
324 }
325
326 /*
327 * Use the blinding method and optimisation suggested in section 10 of:
328 * KOCHER, Paul C. Timing attacks on implementations of Diffie-Hellman, RSA,
329 * DSS, and other systems. In : Advances in Cryptology-CRYPTO'96. Springer
330 * Berlin Heidelberg, 1996. p. 104-113.
331 */
dhm_update_blinding(mbedtls_dhm_context * ctx,int (* f_rng)(void *,unsigned char *,size_t),void * p_rng)332 static int dhm_update_blinding( mbedtls_dhm_context *ctx,
333 int (*f_rng)(void *, unsigned char *, size_t), void *p_rng )
334 {
335 int ret, count;
336
337 /*
338 * Don't use any blinding the first time a particular X is used,
339 * but remember it to use blinding next time.
340 */
341 if( mbedtls_mpi_cmp_mpi( &ctx->X, &ctx->pX ) != 0 )
342 {
343 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &ctx->pX, &ctx->X ) );
344 MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &ctx->Vi, 1 ) );
345 MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &ctx->Vf, 1 ) );
346
347 return( 0 );
348 }
349
350 /*
351 * Ok, we need blinding. Can we re-use existing values?
352 * If yes, just update them by squaring them.
353 */
354 if( mbedtls_mpi_cmp_int( &ctx->Vi, 1 ) != 0 )
355 {
356 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &ctx->Vi, &ctx->Vi, &ctx->Vi ) );
357 MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &ctx->Vi, &ctx->Vi, &ctx->P ) );
358
359 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &ctx->Vf, &ctx->Vf, &ctx->Vf ) );
360 MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &ctx->Vf, &ctx->Vf, &ctx->P ) );
361
362 return( 0 );
363 }
364
365 /*
366 * We need to generate blinding values from scratch
367 */
368
369 /* Vi = random( 2, P-1 ) */
370 count = 0;
371 do
372 {
373 MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( &ctx->Vi, mbedtls_mpi_size( &ctx->P ), f_rng, p_rng ) );
374
375 while( mbedtls_mpi_cmp_mpi( &ctx->Vi, &ctx->P ) >= 0 )
376 MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &ctx->Vi, 1 ) );
377
378 if( count++ > 10 )
379 return( MBEDTLS_ERR_MPI_NOT_ACCEPTABLE );
380 }
381 while( mbedtls_mpi_cmp_int( &ctx->Vi, 1 ) <= 0 );
382
383 /* Vf = Vi^-X mod P */
384 MBEDTLS_MPI_CHK( mbedtls_mpi_inv_mod( &ctx->Vf, &ctx->Vi, &ctx->P ) );
385 MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &ctx->Vf, &ctx->Vf, &ctx->X, &ctx->P, &ctx->RP ) );
386
387 cleanup:
388 return( ret );
389 }
390
391 /*
392 * Derive and export the shared secret (G^Y)^X mod P
393 */
mbedtls_dhm_calc_secret(mbedtls_dhm_context * ctx,unsigned char * output,size_t output_size,size_t * olen,int (* f_rng)(void *,unsigned char *,size_t),void * p_rng)394 int mbedtls_dhm_calc_secret( mbedtls_dhm_context *ctx,
395 unsigned char *output, size_t output_size, size_t *olen,
396 int (*f_rng)(void *, unsigned char *, size_t),
397 void *p_rng )
398 {
399 int ret;
400 mbedtls_mpi GYb;
401 DHM_VALIDATE_RET( ctx != NULL );
402 DHM_VALIDATE_RET( output != NULL );
403 DHM_VALIDATE_RET( olen != NULL );
404
405 if( output_size < ctx->len )
406 return( MBEDTLS_ERR_DHM_BAD_INPUT_DATA );
407
408 if( ( ret = dhm_check_range( &ctx->GY, &ctx->P ) ) != 0 )
409 return( ret );
410
411 mbedtls_mpi_init( &GYb );
412
413 /* Blind peer's value */
414 if( f_rng != NULL )
415 {
416 MBEDTLS_MPI_CHK( dhm_update_blinding( ctx, f_rng, p_rng ) );
417 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &GYb, &ctx->GY, &ctx->Vi ) );
418 MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &GYb, &GYb, &ctx->P ) );
419 }
420 else
421 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &GYb, &ctx->GY ) );
422
423 /* Do modular exponentiation */
424 MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &ctx->K, &GYb, &ctx->X,
425 &ctx->P, &ctx->RP ) );
426
427 /* Unblind secret value */
428 if( f_rng != NULL )
429 {
430 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &ctx->K, &ctx->K, &ctx->Vf ) );
431 MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &ctx->K, &ctx->K, &ctx->P ) );
432 }
433
434 *olen = mbedtls_mpi_size( &ctx->K );
435
436 MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &ctx->K, output, *olen ) );
437
438 cleanup:
439 mbedtls_mpi_free( &GYb );
440
441 if( ret != 0 )
442 return( MBEDTLS_ERR_DHM_CALC_SECRET_FAILED + ret );
443
444 return( 0 );
445 }
446
447 /*
448 * Free the components of a DHM key
449 */
mbedtls_dhm_free(mbedtls_dhm_context * ctx)450 void mbedtls_dhm_free( mbedtls_dhm_context *ctx )
451 {
452 if( ctx == NULL )
453 return;
454
455 mbedtls_mpi_free( &ctx->pX );
456 mbedtls_mpi_free( &ctx->Vf );
457 mbedtls_mpi_free( &ctx->Vi );
458 mbedtls_mpi_free( &ctx->RP );
459 mbedtls_mpi_free( &ctx->K );
460 mbedtls_mpi_free( &ctx->GY );
461 mbedtls_mpi_free( &ctx->GX );
462 mbedtls_mpi_free( &ctx->X );
463 mbedtls_mpi_free( &ctx->G );
464 mbedtls_mpi_free( &ctx->P );
465
466 mbedtls_platform_zeroize( ctx, sizeof( mbedtls_dhm_context ) );
467 }
468
469 #if defined(MBEDTLS_ASN1_PARSE_C)
470 /*
471 * Parse DHM parameters
472 */
mbedtls_dhm_parse_dhm(mbedtls_dhm_context * dhm,const unsigned char * dhmin,size_t dhminlen)473 int mbedtls_dhm_parse_dhm( mbedtls_dhm_context *dhm, const unsigned char *dhmin,
474 size_t dhminlen )
475 {
476 int ret;
477 size_t len;
478 unsigned char *p, *end;
479 #if defined(MBEDTLS_PEM_PARSE_C)
480 mbedtls_pem_context pem;
481 #endif /* MBEDTLS_PEM_PARSE_C */
482
483 DHM_VALIDATE_RET( dhm != NULL );
484 DHM_VALIDATE_RET( dhmin != NULL );
485
486 #if defined(MBEDTLS_PEM_PARSE_C)
487 mbedtls_pem_init( &pem );
488
489 /* Avoid calling mbedtls_pem_read_buffer() on non-null-terminated string */
490 if( dhminlen == 0 || dhmin[dhminlen - 1] != '\0' )
491 ret = MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT;
492 else
493 ret = mbedtls_pem_read_buffer( &pem,
494 "-----BEGIN DH PARAMETERS-----",
495 "-----END DH PARAMETERS-----",
496 dhmin, NULL, 0, &dhminlen );
497
498 if( ret == 0 )
499 {
500 /*
501 * Was PEM encoded
502 */
503 dhminlen = pem.buflen;
504 }
505 else if( ret != MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT )
506 goto exit;
507
508 p = ( ret == 0 ) ? pem.buf : (unsigned char *) dhmin;
509 #else
510 p = (unsigned char *) dhmin;
511 #endif /* MBEDTLS_PEM_PARSE_C */
512 end = p + dhminlen;
513
514 /*
515 * DHParams ::= SEQUENCE {
516 * prime INTEGER, -- P
517 * generator INTEGER, -- g
518 * privateValueLength INTEGER OPTIONAL
519 * }
520 */
521 if( ( ret = mbedtls_asn1_get_tag( &p, end, &len,
522 MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 )
523 {
524 ret = MBEDTLS_ERR_DHM_INVALID_FORMAT + ret;
525 goto exit;
526 }
527
528 end = p + len;
529
530 if( ( ret = mbedtls_asn1_get_mpi( &p, end, &dhm->P ) ) != 0 ||
531 ( ret = mbedtls_asn1_get_mpi( &p, end, &dhm->G ) ) != 0 )
532 {
533 ret = MBEDTLS_ERR_DHM_INVALID_FORMAT + ret;
534 goto exit;
535 }
536
537 if( p != end )
538 {
539 /* This might be the optional privateValueLength.
540 * If so, we can cleanly discard it */
541 mbedtls_mpi rec;
542 mbedtls_mpi_init( &rec );
543 ret = mbedtls_asn1_get_mpi( &p, end, &rec );
544 mbedtls_mpi_free( &rec );
545 if ( ret != 0 )
546 {
547 ret = MBEDTLS_ERR_DHM_INVALID_FORMAT + ret;
548 goto exit;
549 }
550 if ( p != end )
551 {
552 ret = MBEDTLS_ERR_DHM_INVALID_FORMAT +
553 MBEDTLS_ERR_ASN1_LENGTH_MISMATCH;
554 goto exit;
555 }
556 }
557
558 ret = 0;
559
560 dhm->len = mbedtls_mpi_size( &dhm->P );
561
562 exit:
563 #if defined(MBEDTLS_PEM_PARSE_C)
564 mbedtls_pem_free( &pem );
565 #endif
566 if( ret != 0 )
567 mbedtls_dhm_free( dhm );
568
569 return( ret );
570 }
571
572 #if defined(MBEDTLS_FS_IO)
573 /*
574 * Load all data from a file into a given buffer.
575 *
576 * The file is expected to contain either PEM or DER encoded data.
577 * A terminating null byte is always appended. It is included in the announced
578 * length only if the data looks like it is PEM encoded.
579 */
load_file(const char * path,unsigned char ** buf,size_t * n)580 static int load_file( const char *path, unsigned char **buf, size_t *n )
581 {
582 FILE *f;
583 long size;
584
585 if( ( f = fopen( path, "rb" ) ) == NULL )
586 return( MBEDTLS_ERR_DHM_FILE_IO_ERROR );
587
588 fseek( f, 0, SEEK_END );
589 if( ( size = ftell( f ) ) == -1 )
590 {
591 fclose( f );
592 return( MBEDTLS_ERR_DHM_FILE_IO_ERROR );
593 }
594 fseek( f, 0, SEEK_SET );
595
596 *n = (size_t) size;
597
598 if( *n + 1 == 0 ||
599 ( *buf = mbedtls_calloc( 1, *n + 1 ) ) == NULL )
600 {
601 fclose( f );
602 return( MBEDTLS_ERR_DHM_ALLOC_FAILED );
603 }
604
605 if( fread( *buf, 1, *n, f ) != *n )
606 {
607 fclose( f );
608
609 mbedtls_platform_zeroize( *buf, *n + 1 );
610 mbedtls_free( *buf );
611
612 return( MBEDTLS_ERR_DHM_FILE_IO_ERROR );
613 }
614
615 fclose( f );
616
617 (*buf)[*n] = '\0';
618
619 if( strstr( (const char *) *buf, "-----BEGIN " ) != NULL )
620 ++*n;
621
622 return( 0 );
623 }
624
625 /*
626 * Load and parse DHM parameters
627 */
mbedtls_dhm_parse_dhmfile(mbedtls_dhm_context * dhm,const char * path)628 int mbedtls_dhm_parse_dhmfile( mbedtls_dhm_context *dhm, const char *path )
629 {
630 int ret;
631 size_t n;
632 unsigned char *buf;
633 DHM_VALIDATE_RET( dhm != NULL );
634 DHM_VALIDATE_RET( path != NULL );
635
636 if( ( ret = load_file( path, &buf, &n ) ) != 0 )
637 return( ret );
638
639 ret = mbedtls_dhm_parse_dhm( dhm, buf, n );
640
641 mbedtls_platform_zeroize( buf, n );
642 mbedtls_free( buf );
643
644 return( ret );
645 }
646 #endif /* MBEDTLS_FS_IO */
647 #endif /* MBEDTLS_ASN1_PARSE_C */
648 #endif /* MBEDTLS_DHM_ALT */
649
650 #if defined(MBEDTLS_SELF_TEST)
651
652 static const char mbedtls_test_dhm_params[] =
653 "-----BEGIN DH PARAMETERS-----\r\n"
654 "MIGHAoGBAJ419DBEOgmQTzo5qXl5fQcN9TN455wkOL7052HzxxRVMyhYmwQcgJvh\r\n"
655 "1sa18fyfR9OiVEMYglOpkqVoGLN7qd5aQNNi5W7/C+VBdHTBJcGZJyyP5B3qcz32\r\n"
656 "9mLJKudlVudV0Qxk5qUJaPZ/xupz0NyoVpviuiBOI1gNi8ovSXWzAgEC\r\n"
657 "-----END DH PARAMETERS-----\r\n";
658
659 static const size_t mbedtls_test_dhm_params_len = sizeof( mbedtls_test_dhm_params );
660
661 /*
662 * Checkup routine
663 */
mbedtls_dhm_self_test(int verbose)664 int mbedtls_dhm_self_test( int verbose )
665 {
666 int ret;
667 mbedtls_dhm_context dhm;
668
669 mbedtls_dhm_init( &dhm );
670
671 if( verbose != 0 )
672 mbedtls_printf( " DHM parameter load: " );
673
674 if( ( ret = mbedtls_dhm_parse_dhm( &dhm,
675 (const unsigned char *) mbedtls_test_dhm_params,
676 mbedtls_test_dhm_params_len ) ) != 0 )
677 {
678 if( verbose != 0 )
679 mbedtls_printf( "failed\n" );
680
681 ret = 1;
682 goto exit;
683 }
684
685 if( verbose != 0 )
686 mbedtls_printf( "passed\n\n" );
687
688 exit:
689 mbedtls_dhm_free( &dhm );
690
691 return( ret );
692 }
693
694 #endif /* MBEDTLS_SELF_TEST */
695
696 #endif /* MBEDTLS_DHM_C */
697