1 /*
2 * The RSA public-key cryptosystem
3 *
4 * Copyright The Mbed TLS Contributors
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
20 /*
21 * The following sources were referenced in the design of this implementation
22 * of the RSA algorithm:
23 *
24 * [1] A method for obtaining digital signatures and public-key cryptosystems
25 * R Rivest, A Shamir, and L Adleman
26 * http://people.csail.mit.edu/rivest/pubs.html#RSA78
27 *
28 * [2] Handbook of Applied Cryptography - 1997, Chapter 8
29 * Menezes, van Oorschot and Vanstone
30 *
31 * [3] Malware Guard Extension: Using SGX to Conceal Cache Attacks
32 * Michael Schwarz, Samuel Weiser, Daniel Gruss, Clémentine Maurice and
33 * Stefan Mangard
34 * https://arxiv.org/abs/1702.08719v2
35 *
36 */
37
38 #include "common.h"
39
40 #if defined(MBEDTLS_RSA_C)
41
42 #include "mbedtls/rsa.h"
43 #include "rsa_alt_helpers.h"
44 #include "mbedtls/oid.h"
45 #include "mbedtls/platform_util.h"
46 #include "mbedtls/error.h"
47
48 #include <string.h>
49
50 #if defined(MBEDTLS_PKCS1_V21)
51 #include "mbedtls/md.h"
52 #endif
53
54 #if defined(MBEDTLS_PKCS1_V15) && !defined(__OpenBSD__) && !defined(__NetBSD__)
55 #include <stdlib.h>
56 #endif
57
58 #if defined(MBEDTLS_PLATFORM_C)
59 #include "mbedtls/platform.h"
60 #else
61 #include <stdio.h>
62 #define mbedtls_printf printf
63 #define mbedtls_calloc calloc
64 #define mbedtls_free free
65 #endif
66
67 #if !defined(MBEDTLS_RSA_ALT)
68
69 /* Parameter validation macros */
70 #define RSA_VALIDATE_RET( cond ) \
71 MBEDTLS_INTERNAL_VALIDATE_RET( cond, MBEDTLS_ERR_RSA_BAD_INPUT_DATA )
72 #define RSA_VALIDATE( cond ) \
73 MBEDTLS_INTERNAL_VALIDATE( cond )
74
75 #if defined(MBEDTLS_PKCS1_V15)
76 /* constant-time buffer comparison */
mbedtls_safer_memcmp(const void * a,const void * b,size_t n)77 static inline int mbedtls_safer_memcmp( const void *a, const void *b, size_t n )
78 {
79 size_t i;
80 const unsigned char *A = (const unsigned char *) a;
81 const unsigned char *B = (const unsigned char *) b;
82 unsigned char diff = 0;
83
84 for( i = 0; i < n; i++ )
85 diff |= A[i] ^ B[i];
86
87 return( diff );
88 }
89 #endif /* MBEDTLS_PKCS1_V15 */
90
mbedtls_rsa_import(mbedtls_rsa_context * ctx,const mbedtls_mpi * N,const mbedtls_mpi * P,const mbedtls_mpi * Q,const mbedtls_mpi * D,const mbedtls_mpi * E)91 int mbedtls_rsa_import( mbedtls_rsa_context *ctx,
92 const mbedtls_mpi *N,
93 const mbedtls_mpi *P, const mbedtls_mpi *Q,
94 const mbedtls_mpi *D, const mbedtls_mpi *E )
95 {
96 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
97 RSA_VALIDATE_RET( ctx != NULL );
98
99 if( ( N != NULL && ( ret = mbedtls_mpi_copy( &ctx->N, N ) ) != 0 ) ||
100 ( P != NULL && ( ret = mbedtls_mpi_copy( &ctx->P, P ) ) != 0 ) ||
101 ( Q != NULL && ( ret = mbedtls_mpi_copy( &ctx->Q, Q ) ) != 0 ) ||
102 ( D != NULL && ( ret = mbedtls_mpi_copy( &ctx->D, D ) ) != 0 ) ||
103 ( E != NULL && ( ret = mbedtls_mpi_copy( &ctx->E, E ) ) != 0 ) )
104 {
105 return( MBEDTLS_ERROR_ADD( MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret ) );
106 }
107
108 if( N != NULL )
109 ctx->len = mbedtls_mpi_size( &ctx->N );
110
111 return( 0 );
112 }
113
mbedtls_rsa_import_raw(mbedtls_rsa_context * ctx,unsigned char const * N,size_t N_len,unsigned char const * P,size_t P_len,unsigned char const * Q,size_t Q_len,unsigned char const * D,size_t D_len,unsigned char const * E,size_t E_len)114 int mbedtls_rsa_import_raw( mbedtls_rsa_context *ctx,
115 unsigned char const *N, size_t N_len,
116 unsigned char const *P, size_t P_len,
117 unsigned char const *Q, size_t Q_len,
118 unsigned char const *D, size_t D_len,
119 unsigned char const *E, size_t E_len )
120 {
121 int ret = 0;
122 RSA_VALIDATE_RET( ctx != NULL );
123
124 if( N != NULL )
125 {
126 MBEDTLS_MPI_CHK( mbedtls_mpi_read_binary( &ctx->N, N, N_len ) );
127 ctx->len = mbedtls_mpi_size( &ctx->N );
128 }
129
130 if( P != NULL )
131 MBEDTLS_MPI_CHK( mbedtls_mpi_read_binary( &ctx->P, P, P_len ) );
132
133 if( Q != NULL )
134 MBEDTLS_MPI_CHK( mbedtls_mpi_read_binary( &ctx->Q, Q, Q_len ) );
135
136 if( D != NULL )
137 MBEDTLS_MPI_CHK( mbedtls_mpi_read_binary( &ctx->D, D, D_len ) );
138
139 if( E != NULL )
140 MBEDTLS_MPI_CHK( mbedtls_mpi_read_binary( &ctx->E, E, E_len ) );
141
142 cleanup:
143
144 if( ret != 0 )
145 return( MBEDTLS_ERROR_ADD( MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret ) );
146
147 return( 0 );
148 }
149
150 /*
151 * Checks whether the context fields are set in such a way
152 * that the RSA primitives will be able to execute without error.
153 * It does *not* make guarantees for consistency of the parameters.
154 */
rsa_check_context(mbedtls_rsa_context const * ctx,int is_priv,int blinding_needed)155 static int rsa_check_context( mbedtls_rsa_context const *ctx, int is_priv,
156 int blinding_needed )
157 {
158 #if !defined(MBEDTLS_RSA_NO_CRT)
159 /* blinding_needed is only used for NO_CRT to decide whether
160 * P,Q need to be present or not. */
161 ((void) blinding_needed);
162 #endif
163
164 if( ctx->len != mbedtls_mpi_size( &ctx->N ) ||
165 ctx->len > MBEDTLS_MPI_MAX_SIZE )
166 {
167 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
168 }
169
170 /*
171 * 1. Modular exponentiation needs positive, odd moduli.
172 */
173
174 /* Modular exponentiation wrt. N is always used for
175 * RSA public key operations. */
176 if( mbedtls_mpi_cmp_int( &ctx->N, 0 ) <= 0 ||
177 mbedtls_mpi_get_bit( &ctx->N, 0 ) == 0 )
178 {
179 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
180 }
181
182 #if !defined(MBEDTLS_RSA_NO_CRT)
183 /* Modular exponentiation for P and Q is only
184 * used for private key operations and if CRT
185 * is used. */
186 if( is_priv &&
187 ( mbedtls_mpi_cmp_int( &ctx->P, 0 ) <= 0 ||
188 mbedtls_mpi_get_bit( &ctx->P, 0 ) == 0 ||
189 mbedtls_mpi_cmp_int( &ctx->Q, 0 ) <= 0 ||
190 mbedtls_mpi_get_bit( &ctx->Q, 0 ) == 0 ) )
191 {
192 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
193 }
194 #endif /* !MBEDTLS_RSA_NO_CRT */
195
196 /*
197 * 2. Exponents must be positive
198 */
199
200 /* Always need E for public key operations */
201 if( mbedtls_mpi_cmp_int( &ctx->E, 0 ) <= 0 )
202 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
203
204 #if defined(MBEDTLS_RSA_NO_CRT)
205 /* For private key operations, use D or DP & DQ
206 * as (unblinded) exponents. */
207 if( is_priv && mbedtls_mpi_cmp_int( &ctx->D, 0 ) <= 0 )
208 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
209 #else
210 if( is_priv &&
211 ( mbedtls_mpi_cmp_int( &ctx->DP, 0 ) <= 0 ||
212 mbedtls_mpi_cmp_int( &ctx->DQ, 0 ) <= 0 ) )
213 {
214 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
215 }
216 #endif /* MBEDTLS_RSA_NO_CRT */
217
218 /* Blinding shouldn't make exponents negative either,
219 * so check that P, Q >= 1 if that hasn't yet been
220 * done as part of 1. */
221 #if defined(MBEDTLS_RSA_NO_CRT)
222 if( is_priv && blinding_needed &&
223 ( mbedtls_mpi_cmp_int( &ctx->P, 0 ) <= 0 ||
224 mbedtls_mpi_cmp_int( &ctx->Q, 0 ) <= 0 ) )
225 {
226 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
227 }
228 #endif
229
230 /* It wouldn't lead to an error if it wasn't satisfied,
231 * but check for QP >= 1 nonetheless. */
232 #if !defined(MBEDTLS_RSA_NO_CRT)
233 if( is_priv &&
234 mbedtls_mpi_cmp_int( &ctx->QP, 0 ) <= 0 )
235 {
236 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
237 }
238 #endif
239
240 return( 0 );
241 }
242
mbedtls_rsa_complete(mbedtls_rsa_context * ctx)243 int mbedtls_rsa_complete( mbedtls_rsa_context *ctx )
244 {
245 int ret = 0;
246 int have_N, have_P, have_Q, have_D, have_E;
247 #if !defined(MBEDTLS_RSA_NO_CRT)
248 int have_DP, have_DQ, have_QP;
249 #endif
250 int n_missing, pq_missing, d_missing, is_pub, is_priv;
251
252 RSA_VALIDATE_RET( ctx != NULL );
253
254 have_N = ( mbedtls_mpi_cmp_int( &ctx->N, 0 ) != 0 );
255 have_P = ( mbedtls_mpi_cmp_int( &ctx->P, 0 ) != 0 );
256 have_Q = ( mbedtls_mpi_cmp_int( &ctx->Q, 0 ) != 0 );
257 have_D = ( mbedtls_mpi_cmp_int( &ctx->D, 0 ) != 0 );
258 have_E = ( mbedtls_mpi_cmp_int( &ctx->E, 0 ) != 0 );
259
260 #if !defined(MBEDTLS_RSA_NO_CRT)
261 have_DP = ( mbedtls_mpi_cmp_int( &ctx->DP, 0 ) != 0 );
262 have_DQ = ( mbedtls_mpi_cmp_int( &ctx->DQ, 0 ) != 0 );
263 have_QP = ( mbedtls_mpi_cmp_int( &ctx->QP, 0 ) != 0 );
264 #endif
265
266 /*
267 * Check whether provided parameters are enough
268 * to deduce all others. The following incomplete
269 * parameter sets for private keys are supported:
270 *
271 * (1) P, Q missing.
272 * (2) D and potentially N missing.
273 *
274 */
275
276 n_missing = have_P && have_Q && have_D && have_E;
277 pq_missing = have_N && !have_P && !have_Q && have_D && have_E;
278 d_missing = have_P && have_Q && !have_D && have_E;
279 is_pub = have_N && !have_P && !have_Q && !have_D && have_E;
280
281 /* These three alternatives are mutually exclusive */
282 is_priv = n_missing || pq_missing || d_missing;
283
284 if( !is_priv && !is_pub )
285 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
286
287 /*
288 * Step 1: Deduce N if P, Q are provided.
289 */
290
291 if( !have_N && have_P && have_Q )
292 {
293 if( ( ret = mbedtls_mpi_mul_mpi( &ctx->N, &ctx->P,
294 &ctx->Q ) ) != 0 )
295 {
296 return( MBEDTLS_ERROR_ADD( MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret ) );
297 }
298
299 ctx->len = mbedtls_mpi_size( &ctx->N );
300 }
301
302 /*
303 * Step 2: Deduce and verify all remaining core parameters.
304 */
305
306 if( pq_missing )
307 {
308 ret = mbedtls_rsa_deduce_primes( &ctx->N, &ctx->E, &ctx->D,
309 &ctx->P, &ctx->Q );
310 if( ret != 0 )
311 return( MBEDTLS_ERROR_ADD( MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret ) );
312
313 }
314 else if( d_missing )
315 {
316 if( ( ret = mbedtls_rsa_deduce_private_exponent( &ctx->P,
317 &ctx->Q,
318 &ctx->E,
319 &ctx->D ) ) != 0 )
320 {
321 return( MBEDTLS_ERROR_ADD( MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret ) );
322 }
323 }
324
325 /*
326 * Step 3: Deduce all additional parameters specific
327 * to our current RSA implementation.
328 */
329
330 #if !defined(MBEDTLS_RSA_NO_CRT)
331 if( is_priv && ! ( have_DP && have_DQ && have_QP ) )
332 {
333 ret = mbedtls_rsa_deduce_crt( &ctx->P, &ctx->Q, &ctx->D,
334 &ctx->DP, &ctx->DQ, &ctx->QP );
335 if( ret != 0 )
336 return( MBEDTLS_ERROR_ADD( MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret ) );
337 }
338 #endif /* MBEDTLS_RSA_NO_CRT */
339
340 /*
341 * Step 3: Basic sanity checks
342 */
343
344 return( rsa_check_context( ctx, is_priv, 1 ) );
345 }
346
mbedtls_rsa_export_raw(const mbedtls_rsa_context * ctx,unsigned char * N,size_t N_len,unsigned char * P,size_t P_len,unsigned char * Q,size_t Q_len,unsigned char * D,size_t D_len,unsigned char * E,size_t E_len)347 int mbedtls_rsa_export_raw( const mbedtls_rsa_context *ctx,
348 unsigned char *N, size_t N_len,
349 unsigned char *P, size_t P_len,
350 unsigned char *Q, size_t Q_len,
351 unsigned char *D, size_t D_len,
352 unsigned char *E, size_t E_len )
353 {
354 int ret = 0;
355 int is_priv;
356 RSA_VALIDATE_RET( ctx != NULL );
357
358 /* Check if key is private or public */
359 is_priv =
360 mbedtls_mpi_cmp_int( &ctx->N, 0 ) != 0 &&
361 mbedtls_mpi_cmp_int( &ctx->P, 0 ) != 0 &&
362 mbedtls_mpi_cmp_int( &ctx->Q, 0 ) != 0 &&
363 mbedtls_mpi_cmp_int( &ctx->D, 0 ) != 0 &&
364 mbedtls_mpi_cmp_int( &ctx->E, 0 ) != 0;
365
366 if( !is_priv )
367 {
368 /* If we're trying to export private parameters for a public key,
369 * something must be wrong. */
370 if( P != NULL || Q != NULL || D != NULL )
371 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
372
373 }
374
375 if( N != NULL )
376 MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &ctx->N, N, N_len ) );
377
378 if( P != NULL )
379 MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &ctx->P, P, P_len ) );
380
381 if( Q != NULL )
382 MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &ctx->Q, Q, Q_len ) );
383
384 if( D != NULL )
385 MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &ctx->D, D, D_len ) );
386
387 if( E != NULL )
388 MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &ctx->E, E, E_len ) );
389
390 cleanup:
391
392 return( ret );
393 }
394
mbedtls_rsa_export(const mbedtls_rsa_context * ctx,mbedtls_mpi * N,mbedtls_mpi * P,mbedtls_mpi * Q,mbedtls_mpi * D,mbedtls_mpi * E)395 int mbedtls_rsa_export( const mbedtls_rsa_context *ctx,
396 mbedtls_mpi *N, mbedtls_mpi *P, mbedtls_mpi *Q,
397 mbedtls_mpi *D, mbedtls_mpi *E )
398 {
399 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
400 int is_priv;
401 RSA_VALIDATE_RET( ctx != NULL );
402
403 /* Check if key is private or public */
404 is_priv =
405 mbedtls_mpi_cmp_int( &ctx->N, 0 ) != 0 &&
406 mbedtls_mpi_cmp_int( &ctx->P, 0 ) != 0 &&
407 mbedtls_mpi_cmp_int( &ctx->Q, 0 ) != 0 &&
408 mbedtls_mpi_cmp_int( &ctx->D, 0 ) != 0 &&
409 mbedtls_mpi_cmp_int( &ctx->E, 0 ) != 0;
410
411 if( !is_priv )
412 {
413 /* If we're trying to export private parameters for a public key,
414 * something must be wrong. */
415 if( P != NULL || Q != NULL || D != NULL )
416 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
417
418 }
419
420 /* Export all requested core parameters. */
421
422 if( ( N != NULL && ( ret = mbedtls_mpi_copy( N, &ctx->N ) ) != 0 ) ||
423 ( P != NULL && ( ret = mbedtls_mpi_copy( P, &ctx->P ) ) != 0 ) ||
424 ( Q != NULL && ( ret = mbedtls_mpi_copy( Q, &ctx->Q ) ) != 0 ) ||
425 ( D != NULL && ( ret = mbedtls_mpi_copy( D, &ctx->D ) ) != 0 ) ||
426 ( E != NULL && ( ret = mbedtls_mpi_copy( E, &ctx->E ) ) != 0 ) )
427 {
428 return( ret );
429 }
430
431 return( 0 );
432 }
433
434 /*
435 * Export CRT parameters
436 * This must also be implemented if CRT is not used, for being able to
437 * write DER encoded RSA keys. The helper function mbedtls_rsa_deduce_crt
438 * can be used in this case.
439 */
mbedtls_rsa_export_crt(const mbedtls_rsa_context * ctx,mbedtls_mpi * DP,mbedtls_mpi * DQ,mbedtls_mpi * QP)440 int mbedtls_rsa_export_crt( const mbedtls_rsa_context *ctx,
441 mbedtls_mpi *DP, mbedtls_mpi *DQ, mbedtls_mpi *QP )
442 {
443 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
444 int is_priv;
445 RSA_VALIDATE_RET( ctx != NULL );
446
447 /* Check if key is private or public */
448 is_priv =
449 mbedtls_mpi_cmp_int( &ctx->N, 0 ) != 0 &&
450 mbedtls_mpi_cmp_int( &ctx->P, 0 ) != 0 &&
451 mbedtls_mpi_cmp_int( &ctx->Q, 0 ) != 0 &&
452 mbedtls_mpi_cmp_int( &ctx->D, 0 ) != 0 &&
453 mbedtls_mpi_cmp_int( &ctx->E, 0 ) != 0;
454
455 if( !is_priv )
456 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
457
458 #if !defined(MBEDTLS_RSA_NO_CRT)
459 /* Export all requested blinding parameters. */
460 if( ( DP != NULL && ( ret = mbedtls_mpi_copy( DP, &ctx->DP ) ) != 0 ) ||
461 ( DQ != NULL && ( ret = mbedtls_mpi_copy( DQ, &ctx->DQ ) ) != 0 ) ||
462 ( QP != NULL && ( ret = mbedtls_mpi_copy( QP, &ctx->QP ) ) != 0 ) )
463 {
464 return( MBEDTLS_ERROR_ADD( MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret ) );
465 }
466 #else
467 if( ( ret = mbedtls_rsa_deduce_crt( &ctx->P, &ctx->Q, &ctx->D,
468 DP, DQ, QP ) ) != 0 )
469 {
470 return( MBEDTLS_ERROR_ADD( MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret ) );
471 }
472 #endif
473
474 return( 0 );
475 }
476
477 /*
478 * Initialize an RSA context
479 */
mbedtls_rsa_init(mbedtls_rsa_context * ctx)480 void mbedtls_rsa_init( mbedtls_rsa_context *ctx )
481 {
482 RSA_VALIDATE( ctx != NULL );
483
484 memset( ctx, 0, sizeof( mbedtls_rsa_context ) );
485
486 ctx->padding = MBEDTLS_RSA_PKCS_V15;
487 ctx->hash_id = MBEDTLS_MD_NONE;
488
489 #if defined(MBEDTLS_THREADING_C)
490 /* Set ctx->ver to nonzero to indicate that the mutex has been
491 * initialized and will need to be freed. */
492 ctx->ver = 1;
493 mbedtls_mutex_init( &ctx->mutex );
494 #endif
495 }
496
497 /*
498 * Set padding for an existing RSA context
499 */
mbedtls_rsa_set_padding(mbedtls_rsa_context * ctx,int padding,mbedtls_md_type_t hash_id)500 int mbedtls_rsa_set_padding( mbedtls_rsa_context *ctx, int padding,
501 mbedtls_md_type_t hash_id )
502 {
503 switch( padding )
504 {
505 #if defined(MBEDTLS_PKCS1_V15)
506 case MBEDTLS_RSA_PKCS_V15:
507 break;
508 #endif
509
510 #if defined(MBEDTLS_PKCS1_V21)
511 case MBEDTLS_RSA_PKCS_V21:
512 break;
513 #endif
514 default:
515 return( MBEDTLS_ERR_RSA_INVALID_PADDING );
516 }
517
518 if( ( padding == MBEDTLS_RSA_PKCS_V21 ) &&
519 ( hash_id != MBEDTLS_MD_NONE ) )
520 {
521 const mbedtls_md_info_t *md_info;
522
523 md_info = mbedtls_md_info_from_type( hash_id );
524 if( md_info == NULL )
525 return( MBEDTLS_ERR_RSA_INVALID_PADDING );
526 }
527
528 ctx->padding = padding;
529 ctx->hash_id = hash_id;
530
531 return( 0 );
532 }
533
534 /*
535 * Get length in bytes of RSA modulus
536 */
537
mbedtls_rsa_get_len(const mbedtls_rsa_context * ctx)538 size_t mbedtls_rsa_get_len( const mbedtls_rsa_context *ctx )
539 {
540 return( ctx->len );
541 }
542
543
544 #if defined(MBEDTLS_GENPRIME)
545
546 /*
547 * Generate an RSA keypair
548 *
549 * This generation method follows the RSA key pair generation procedure of
550 * FIPS 186-4 if 2^16 < exponent < 2^256 and nbits = 2048 or nbits = 3072.
551 */
mbedtls_rsa_gen_key(mbedtls_rsa_context * ctx,int (* f_rng)(void *,unsigned char *,size_t),void * p_rng,unsigned int nbits,int exponent)552 int mbedtls_rsa_gen_key( mbedtls_rsa_context *ctx,
553 int (*f_rng)(void *, unsigned char *, size_t),
554 void *p_rng,
555 unsigned int nbits, int exponent )
556 {
557 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
558 mbedtls_mpi H, G, L;
559 int prime_quality = 0;
560 RSA_VALIDATE_RET( ctx != NULL );
561 RSA_VALIDATE_RET( f_rng != NULL );
562
563 /*
564 * If the modulus is 1024 bit long or shorter, then the security strength of
565 * the RSA algorithm is less than or equal to 80 bits and therefore an error
566 * rate of 2^-80 is sufficient.
567 */
568 if( nbits > 1024 )
569 prime_quality = MBEDTLS_MPI_GEN_PRIME_FLAG_LOW_ERR;
570
571 mbedtls_mpi_init( &H );
572 mbedtls_mpi_init( &G );
573 mbedtls_mpi_init( &L );
574
575 if( nbits < 128 || exponent < 3 || nbits % 2 != 0 )
576 {
577 ret = MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
578 goto cleanup;
579 }
580
581 /*
582 * find primes P and Q with Q < P so that:
583 * 1. |P-Q| > 2^( nbits / 2 - 100 )
584 * 2. GCD( E, (P-1)*(Q-1) ) == 1
585 * 3. E^-1 mod LCM(P-1, Q-1) > 2^( nbits / 2 )
586 */
587 MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &ctx->E, exponent ) );
588
589 do
590 {
591 MBEDTLS_MPI_CHK( mbedtls_mpi_gen_prime( &ctx->P, nbits >> 1,
592 prime_quality, f_rng, p_rng ) );
593
594 MBEDTLS_MPI_CHK( mbedtls_mpi_gen_prime( &ctx->Q, nbits >> 1,
595 prime_quality, f_rng, p_rng ) );
596
597 /* make sure the difference between p and q is not too small (FIPS 186-4 §B.3.3 step 5.4) */
598 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &H, &ctx->P, &ctx->Q ) );
599 if( mbedtls_mpi_bitlen( &H ) <= ( ( nbits >= 200 ) ? ( ( nbits >> 1 ) - 99 ) : 0 ) )
600 continue;
601
602 /* not required by any standards, but some users rely on the fact that P > Q */
603 if( H.s < 0 )
604 mbedtls_mpi_swap( &ctx->P, &ctx->Q );
605
606 /* Temporarily replace P,Q by P-1, Q-1 */
607 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &ctx->P, &ctx->P, 1 ) );
608 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &ctx->Q, &ctx->Q, 1 ) );
609 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &H, &ctx->P, &ctx->Q ) );
610
611 /* check GCD( E, (P-1)*(Q-1) ) == 1 (FIPS 186-4 §B.3.1 criterion 2(a)) */
612 MBEDTLS_MPI_CHK( mbedtls_mpi_gcd( &G, &ctx->E, &H ) );
613 if( mbedtls_mpi_cmp_int( &G, 1 ) != 0 )
614 continue;
615
616 /* compute smallest possible D = E^-1 mod LCM(P-1, Q-1) (FIPS 186-4 §B.3.1 criterion 3(b)) */
617 MBEDTLS_MPI_CHK( mbedtls_mpi_gcd( &G, &ctx->P, &ctx->Q ) );
618 MBEDTLS_MPI_CHK( mbedtls_mpi_div_mpi( &L, NULL, &H, &G ) );
619 MBEDTLS_MPI_CHK( mbedtls_mpi_inv_mod( &ctx->D, &ctx->E, &L ) );
620
621 if( mbedtls_mpi_bitlen( &ctx->D ) <= ( ( nbits + 1 ) / 2 ) ) // (FIPS 186-4 §B.3.1 criterion 3(a))
622 continue;
623
624 break;
625 }
626 while( 1 );
627
628 /* Restore P,Q */
629 MBEDTLS_MPI_CHK( mbedtls_mpi_add_int( &ctx->P, &ctx->P, 1 ) );
630 MBEDTLS_MPI_CHK( mbedtls_mpi_add_int( &ctx->Q, &ctx->Q, 1 ) );
631
632 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &ctx->N, &ctx->P, &ctx->Q ) );
633
634 ctx->len = mbedtls_mpi_size( &ctx->N );
635
636 #if !defined(MBEDTLS_RSA_NO_CRT)
637 /*
638 * DP = D mod (P - 1)
639 * DQ = D mod (Q - 1)
640 * QP = Q^-1 mod P
641 */
642 MBEDTLS_MPI_CHK( mbedtls_rsa_deduce_crt( &ctx->P, &ctx->Q, &ctx->D,
643 &ctx->DP, &ctx->DQ, &ctx->QP ) );
644 #endif /* MBEDTLS_RSA_NO_CRT */
645
646 /* Double-check */
647 MBEDTLS_MPI_CHK( mbedtls_rsa_check_privkey( ctx ) );
648
649 cleanup:
650
651 mbedtls_mpi_free( &H );
652 mbedtls_mpi_free( &G );
653 mbedtls_mpi_free( &L );
654
655 if( ret != 0 )
656 {
657 mbedtls_rsa_free( ctx );
658
659 if( ( -ret & ~0x7f ) == 0 )
660 ret = MBEDTLS_ERROR_ADD( MBEDTLS_ERR_RSA_KEY_GEN_FAILED, ret );
661 return( ret );
662 }
663
664 return( 0 );
665 }
666
667 #endif /* MBEDTLS_GENPRIME */
668
669 /*
670 * Check a public RSA key
671 */
mbedtls_rsa_check_pubkey(const mbedtls_rsa_context * ctx)672 int mbedtls_rsa_check_pubkey( const mbedtls_rsa_context *ctx )
673 {
674 RSA_VALIDATE_RET( ctx != NULL );
675
676 if( rsa_check_context( ctx, 0 /* public */, 0 /* no blinding */ ) != 0 )
677 return( MBEDTLS_ERR_RSA_KEY_CHECK_FAILED );
678
679 if( mbedtls_mpi_bitlen( &ctx->N ) < 128 )
680 {
681 return( MBEDTLS_ERR_RSA_KEY_CHECK_FAILED );
682 }
683
684 if( mbedtls_mpi_get_bit( &ctx->E, 0 ) == 0 ||
685 mbedtls_mpi_bitlen( &ctx->E ) < 2 ||
686 mbedtls_mpi_cmp_mpi( &ctx->E, &ctx->N ) >= 0 )
687 {
688 return( MBEDTLS_ERR_RSA_KEY_CHECK_FAILED );
689 }
690
691 return( 0 );
692 }
693
694 /*
695 * Check for the consistency of all fields in an RSA private key context
696 */
mbedtls_rsa_check_privkey(const mbedtls_rsa_context * ctx)697 int mbedtls_rsa_check_privkey( const mbedtls_rsa_context *ctx )
698 {
699 RSA_VALIDATE_RET( ctx != NULL );
700
701 if( mbedtls_rsa_check_pubkey( ctx ) != 0 ||
702 rsa_check_context( ctx, 1 /* private */, 1 /* blinding */ ) != 0 )
703 {
704 return( MBEDTLS_ERR_RSA_KEY_CHECK_FAILED );
705 }
706
707 if( mbedtls_rsa_validate_params( &ctx->N, &ctx->P, &ctx->Q,
708 &ctx->D, &ctx->E, NULL, NULL ) != 0 )
709 {
710 return( MBEDTLS_ERR_RSA_KEY_CHECK_FAILED );
711 }
712
713 #if !defined(MBEDTLS_RSA_NO_CRT)
714 else if( mbedtls_rsa_validate_crt( &ctx->P, &ctx->Q, &ctx->D,
715 &ctx->DP, &ctx->DQ, &ctx->QP ) != 0 )
716 {
717 return( MBEDTLS_ERR_RSA_KEY_CHECK_FAILED );
718 }
719 #endif
720
721 return( 0 );
722 }
723
724 /*
725 * Check if contexts holding a public and private key match
726 */
mbedtls_rsa_check_pub_priv(const mbedtls_rsa_context * pub,const mbedtls_rsa_context * prv)727 int mbedtls_rsa_check_pub_priv( const mbedtls_rsa_context *pub,
728 const mbedtls_rsa_context *prv )
729 {
730 RSA_VALIDATE_RET( pub != NULL );
731 RSA_VALIDATE_RET( prv != NULL );
732
733 if( mbedtls_rsa_check_pubkey( pub ) != 0 ||
734 mbedtls_rsa_check_privkey( prv ) != 0 )
735 {
736 return( MBEDTLS_ERR_RSA_KEY_CHECK_FAILED );
737 }
738
739 if( mbedtls_mpi_cmp_mpi( &pub->N, &prv->N ) != 0 ||
740 mbedtls_mpi_cmp_mpi( &pub->E, &prv->E ) != 0 )
741 {
742 return( MBEDTLS_ERR_RSA_KEY_CHECK_FAILED );
743 }
744
745 return( 0 );
746 }
747
748 /*
749 * Do an RSA public key operation
750 */
mbedtls_rsa_public(mbedtls_rsa_context * ctx,const unsigned char * input,unsigned char * output)751 int mbedtls_rsa_public( mbedtls_rsa_context *ctx,
752 const unsigned char *input,
753 unsigned char *output )
754 {
755 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
756 size_t olen;
757 mbedtls_mpi T;
758 RSA_VALIDATE_RET( ctx != NULL );
759 RSA_VALIDATE_RET( input != NULL );
760 RSA_VALIDATE_RET( output != NULL );
761
762 if( rsa_check_context( ctx, 0 /* public */, 0 /* no blinding */ ) )
763 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
764
765 mbedtls_mpi_init( &T );
766
767 #if defined(MBEDTLS_THREADING_C)
768 if( ( ret = mbedtls_mutex_lock( &ctx->mutex ) ) != 0 )
769 return( ret );
770 #endif
771
772 MBEDTLS_MPI_CHK( mbedtls_mpi_read_binary( &T, input, ctx->len ) );
773
774 if( mbedtls_mpi_cmp_mpi( &T, &ctx->N ) >= 0 )
775 {
776 ret = MBEDTLS_ERR_MPI_BAD_INPUT_DATA;
777 goto cleanup;
778 }
779
780 olen = ctx->len;
781 MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &T, &T, &ctx->E, &ctx->N, &ctx->RN ) );
782 MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &T, output, olen ) );
783
784 cleanup:
785 #if defined(MBEDTLS_THREADING_C)
786 if( mbedtls_mutex_unlock( &ctx->mutex ) != 0 )
787 return( MBEDTLS_ERR_THREADING_MUTEX_ERROR );
788 #endif
789
790 mbedtls_mpi_free( &T );
791
792 if( ret != 0 )
793 return( MBEDTLS_ERROR_ADD( MBEDTLS_ERR_RSA_PUBLIC_FAILED, ret ) );
794
795 return( 0 );
796 }
797
798 /*
799 * Generate or update blinding values, see section 10 of:
800 * KOCHER, Paul C. Timing attacks on implementations of Diffie-Hellman, RSA,
801 * DSS, and other systems. In : Advances in Cryptology-CRYPTO'96. Springer
802 * Berlin Heidelberg, 1996. p. 104-113.
803 */
rsa_prepare_blinding(mbedtls_rsa_context * ctx,int (* f_rng)(void *,unsigned char *,size_t),void * p_rng)804 static int rsa_prepare_blinding( mbedtls_rsa_context *ctx,
805 int (*f_rng)(void *, unsigned char *, size_t), void *p_rng )
806 {
807 int ret, count = 0;
808 mbedtls_mpi R;
809
810 mbedtls_mpi_init( &R );
811
812 if( ctx->Vf.p != NULL )
813 {
814 /* We already have blinding values, just update them by squaring */
815 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &ctx->Vi, &ctx->Vi, &ctx->Vi ) );
816 MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &ctx->Vi, &ctx->Vi, &ctx->N ) );
817 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &ctx->Vf, &ctx->Vf, &ctx->Vf ) );
818 MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &ctx->Vf, &ctx->Vf, &ctx->N ) );
819
820 goto cleanup;
821 }
822
823 /* Unblinding value: Vf = random number, invertible mod N */
824 do {
825 if( count++ > 10 )
826 {
827 ret = MBEDTLS_ERR_RSA_RNG_FAILED;
828 goto cleanup;
829 }
830
831 MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( &ctx->Vf, ctx->len - 1, f_rng, p_rng ) );
832
833 /* Compute Vf^-1 as R * (R Vf)^-1 to avoid leaks from inv_mod. */
834 MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( &R, ctx->len - 1, f_rng, p_rng ) );
835 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &ctx->Vi, &ctx->Vf, &R ) );
836 MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &ctx->Vi, &ctx->Vi, &ctx->N ) );
837
838 /* At this point, Vi is invertible mod N if and only if both Vf and R
839 * are invertible mod N. If one of them isn't, we don't need to know
840 * which one, we just loop and choose new values for both of them.
841 * (Each iteration succeeds with overwhelming probability.) */
842 ret = mbedtls_mpi_inv_mod( &ctx->Vi, &ctx->Vi, &ctx->N );
843 if( ret != 0 && ret != MBEDTLS_ERR_MPI_NOT_ACCEPTABLE )
844 goto cleanup;
845
846 } while( ret == MBEDTLS_ERR_MPI_NOT_ACCEPTABLE );
847
848 /* Finish the computation of Vf^-1 = R * (R Vf)^-1 */
849 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &ctx->Vi, &ctx->Vi, &R ) );
850 MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &ctx->Vi, &ctx->Vi, &ctx->N ) );
851
852 /* Blinding value: Vi = Vf^(-e) mod N
853 * (Vi already contains Vf^-1 at this point) */
854 MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &ctx->Vi, &ctx->Vi, &ctx->E, &ctx->N, &ctx->RN ) );
855
856
857 cleanup:
858 mbedtls_mpi_free( &R );
859
860 return( ret );
861 }
862
863 /*
864 * Exponent blinding supposed to prevent side-channel attacks using multiple
865 * traces of measurements to recover the RSA key. The more collisions are there,
866 * the more bits of the key can be recovered. See [3].
867 *
868 * Collecting n collisions with m bit long blinding value requires 2^(m-m/n)
869 * observations on avarage.
870 *
871 * For example with 28 byte blinding to achieve 2 collisions the adversary has
872 * to make 2^112 observations on avarage.
873 *
874 * (With the currently (as of 2017 April) known best algorithms breaking 2048
875 * bit RSA requires approximately as much time as trying out 2^112 random keys.
876 * Thus in this sense with 28 byte blinding the security is not reduced by
877 * side-channel attacks like the one in [3])
878 *
879 * This countermeasure does not help if the key recovery is possible with a
880 * single trace.
881 */
882 #define RSA_EXPONENT_BLINDING 28
883
884 /*
885 * Do an RSA private key operation
886 */
mbedtls_rsa_private(mbedtls_rsa_context * ctx,int (* f_rng)(void *,unsigned char *,size_t),void * p_rng,const unsigned char * input,unsigned char * output)887 int mbedtls_rsa_private( mbedtls_rsa_context *ctx,
888 int (*f_rng)(void *, unsigned char *, size_t),
889 void *p_rng,
890 const unsigned char *input,
891 unsigned char *output )
892 {
893 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
894 size_t olen;
895
896 /* Temporary holding the result */
897 mbedtls_mpi T;
898
899 /* Temporaries holding P-1, Q-1 and the
900 * exponent blinding factor, respectively. */
901 mbedtls_mpi P1, Q1, R;
902
903 #if !defined(MBEDTLS_RSA_NO_CRT)
904 /* Temporaries holding the results mod p resp. mod q. */
905 mbedtls_mpi TP, TQ;
906
907 /* Temporaries holding the blinded exponents for
908 * the mod p resp. mod q computation (if used). */
909 mbedtls_mpi DP_blind, DQ_blind;
910
911 /* Pointers to actual exponents to be used - either the unblinded
912 * or the blinded ones, depending on the presence of a PRNG. */
913 mbedtls_mpi *DP = &ctx->DP;
914 mbedtls_mpi *DQ = &ctx->DQ;
915 #else
916 /* Temporary holding the blinded exponent (if used). */
917 mbedtls_mpi D_blind;
918
919 /* Pointer to actual exponent to be used - either the unblinded
920 * or the blinded one, depending on the presence of a PRNG. */
921 mbedtls_mpi *D = &ctx->D;
922 #endif /* MBEDTLS_RSA_NO_CRT */
923
924 /* Temporaries holding the initial input and the double
925 * checked result; should be the same in the end. */
926 mbedtls_mpi I, C;
927
928 RSA_VALIDATE_RET( ctx != NULL );
929 RSA_VALIDATE_RET( input != NULL );
930 RSA_VALIDATE_RET( output != NULL );
931
932 if( f_rng == NULL )
933 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
934
935 if( rsa_check_context( ctx, 1 /* private key checks */,
936 1 /* blinding on */ ) != 0 )
937 {
938 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
939 }
940
941 #if defined(MBEDTLS_THREADING_C)
942 if( ( ret = mbedtls_mutex_lock( &ctx->mutex ) ) != 0 )
943 return( ret );
944 #endif
945
946 /* MPI Initialization */
947 mbedtls_mpi_init( &T );
948
949 mbedtls_mpi_init( &P1 );
950 mbedtls_mpi_init( &Q1 );
951 mbedtls_mpi_init( &R );
952
953 #if defined(MBEDTLS_RSA_NO_CRT)
954 mbedtls_mpi_init( &D_blind );
955 #else
956 mbedtls_mpi_init( &DP_blind );
957 mbedtls_mpi_init( &DQ_blind );
958 #endif
959
960 #if !defined(MBEDTLS_RSA_NO_CRT)
961 mbedtls_mpi_init( &TP ); mbedtls_mpi_init( &TQ );
962 #endif
963
964 mbedtls_mpi_init( &I );
965 mbedtls_mpi_init( &C );
966
967 /* End of MPI initialization */
968
969 MBEDTLS_MPI_CHK( mbedtls_mpi_read_binary( &T, input, ctx->len ) );
970 if( mbedtls_mpi_cmp_mpi( &T, &ctx->N ) >= 0 )
971 {
972 ret = MBEDTLS_ERR_MPI_BAD_INPUT_DATA;
973 goto cleanup;
974 }
975
976 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &I, &T ) );
977
978 /*
979 * Blinding
980 * T = T * Vi mod N
981 */
982 MBEDTLS_MPI_CHK( rsa_prepare_blinding( ctx, f_rng, p_rng ) );
983 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &T, &T, &ctx->Vi ) );
984 MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &T, &T, &ctx->N ) );
985
986 /*
987 * Exponent blinding
988 */
989 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &P1, &ctx->P, 1 ) );
990 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &Q1, &ctx->Q, 1 ) );
991
992 #if defined(MBEDTLS_RSA_NO_CRT)
993 /*
994 * D_blind = ( P - 1 ) * ( Q - 1 ) * R + D
995 */
996 MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( &R, RSA_EXPONENT_BLINDING,
997 f_rng, p_rng ) );
998 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &D_blind, &P1, &Q1 ) );
999 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &D_blind, &D_blind, &R ) );
1000 MBEDTLS_MPI_CHK( mbedtls_mpi_add_mpi( &D_blind, &D_blind, &ctx->D ) );
1001
1002 D = &D_blind;
1003 #else
1004 /*
1005 * DP_blind = ( P - 1 ) * R + DP
1006 */
1007 MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( &R, RSA_EXPONENT_BLINDING,
1008 f_rng, p_rng ) );
1009 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &DP_blind, &P1, &R ) );
1010 MBEDTLS_MPI_CHK( mbedtls_mpi_add_mpi( &DP_blind, &DP_blind,
1011 &ctx->DP ) );
1012
1013 DP = &DP_blind;
1014
1015 /*
1016 * DQ_blind = ( Q - 1 ) * R + DQ
1017 */
1018 MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( &R, RSA_EXPONENT_BLINDING,
1019 f_rng, p_rng ) );
1020 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &DQ_blind, &Q1, &R ) );
1021 MBEDTLS_MPI_CHK( mbedtls_mpi_add_mpi( &DQ_blind, &DQ_blind,
1022 &ctx->DQ ) );
1023
1024 DQ = &DQ_blind;
1025 #endif /* MBEDTLS_RSA_NO_CRT */
1026
1027 #if defined(MBEDTLS_RSA_NO_CRT)
1028 MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &T, &T, D, &ctx->N, &ctx->RN ) );
1029 #else
1030 /*
1031 * Faster decryption using the CRT
1032 *
1033 * TP = input ^ dP mod P
1034 * TQ = input ^ dQ mod Q
1035 */
1036
1037 MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &TP, &T, DP, &ctx->P, &ctx->RP ) );
1038 MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &TQ, &T, DQ, &ctx->Q, &ctx->RQ ) );
1039
1040 /*
1041 * T = (TP - TQ) * (Q^-1 mod P) mod P
1042 */
1043 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &T, &TP, &TQ ) );
1044 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &TP, &T, &ctx->QP ) );
1045 MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &T, &TP, &ctx->P ) );
1046
1047 /*
1048 * T = TQ + T * Q
1049 */
1050 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &TP, &T, &ctx->Q ) );
1051 MBEDTLS_MPI_CHK( mbedtls_mpi_add_mpi( &T, &TQ, &TP ) );
1052 #endif /* MBEDTLS_RSA_NO_CRT */
1053
1054 /*
1055 * Unblind
1056 * T = T * Vf mod N
1057 */
1058 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &T, &T, &ctx->Vf ) );
1059 MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &T, &T, &ctx->N ) );
1060
1061 /* Verify the result to prevent glitching attacks. */
1062 MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &C, &T, &ctx->E,
1063 &ctx->N, &ctx->RN ) );
1064 if( mbedtls_mpi_cmp_mpi( &C, &I ) != 0 )
1065 {
1066 ret = MBEDTLS_ERR_RSA_VERIFY_FAILED;
1067 goto cleanup;
1068 }
1069
1070 olen = ctx->len;
1071 MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &T, output, olen ) );
1072
1073 cleanup:
1074 #if defined(MBEDTLS_THREADING_C)
1075 if( mbedtls_mutex_unlock( &ctx->mutex ) != 0 )
1076 return( MBEDTLS_ERR_THREADING_MUTEX_ERROR );
1077 #endif
1078
1079 mbedtls_mpi_free( &P1 );
1080 mbedtls_mpi_free( &Q1 );
1081 mbedtls_mpi_free( &R );
1082
1083 #if defined(MBEDTLS_RSA_NO_CRT)
1084 mbedtls_mpi_free( &D_blind );
1085 #else
1086 mbedtls_mpi_free( &DP_blind );
1087 mbedtls_mpi_free( &DQ_blind );
1088 #endif
1089
1090 mbedtls_mpi_free( &T );
1091
1092 #if !defined(MBEDTLS_RSA_NO_CRT)
1093 mbedtls_mpi_free( &TP ); mbedtls_mpi_free( &TQ );
1094 #endif
1095
1096 mbedtls_mpi_free( &C );
1097 mbedtls_mpi_free( &I );
1098
1099 if( ret != 0 && ret >= -0x007f )
1100 return( MBEDTLS_ERROR_ADD( MBEDTLS_ERR_RSA_PRIVATE_FAILED, ret ) );
1101
1102 return( ret );
1103 }
1104
1105 #if defined(MBEDTLS_PKCS1_V21)
1106 /**
1107 * Generate and apply the MGF1 operation (from PKCS#1 v2.1) to a buffer.
1108 *
1109 * \param dst buffer to mask
1110 * \param dlen length of destination buffer
1111 * \param src source of the mask generation
1112 * \param slen length of the source buffer
1113 * \param md_ctx message digest context to use
1114 */
mgf_mask(unsigned char * dst,size_t dlen,unsigned char * src,size_t slen,mbedtls_md_context_t * md_ctx)1115 static int mgf_mask( unsigned char *dst, size_t dlen, unsigned char *src,
1116 size_t slen, mbedtls_md_context_t *md_ctx )
1117 {
1118 unsigned char mask[MBEDTLS_MD_MAX_SIZE];
1119 unsigned char counter[4];
1120 unsigned char *p;
1121 unsigned int hlen;
1122 size_t i, use_len;
1123 int ret = 0;
1124
1125 memset( mask, 0, MBEDTLS_MD_MAX_SIZE );
1126 memset( counter, 0, 4 );
1127
1128 hlen = mbedtls_md_get_size( md_ctx->md_info );
1129
1130 /* Generate and apply dbMask */
1131 p = dst;
1132
1133 while( dlen > 0 )
1134 {
1135 use_len = hlen;
1136 if( dlen < hlen )
1137 use_len = dlen;
1138
1139 if( ( ret = mbedtls_md_starts( md_ctx ) ) != 0 )
1140 goto exit;
1141 if( ( ret = mbedtls_md_update( md_ctx, src, slen ) ) != 0 )
1142 goto exit;
1143 if( ( ret = mbedtls_md_update( md_ctx, counter, 4 ) ) != 0 )
1144 goto exit;
1145 if( ( ret = mbedtls_md_finish( md_ctx, mask ) ) != 0 )
1146 goto exit;
1147
1148 for( i = 0; i < use_len; ++i )
1149 *p++ ^= mask[i];
1150
1151 counter[3]++;
1152
1153 dlen -= use_len;
1154 }
1155
1156 exit:
1157 mbedtls_platform_zeroize( mask, sizeof( mask ) );
1158
1159 return( ret );
1160 }
1161 #endif /* MBEDTLS_PKCS1_V21 */
1162
1163 #if defined(MBEDTLS_PKCS1_V21)
1164 /*
1165 * Implementation of the PKCS#1 v2.1 RSAES-OAEP-ENCRYPT function
1166 */
mbedtls_rsa_rsaes_oaep_encrypt(mbedtls_rsa_context * ctx,int (* f_rng)(void *,unsigned char *,size_t),void * p_rng,const unsigned char * label,size_t label_len,size_t ilen,const unsigned char * input,unsigned char * output)1167 int mbedtls_rsa_rsaes_oaep_encrypt( mbedtls_rsa_context *ctx,
1168 int (*f_rng)(void *, unsigned char *, size_t),
1169 void *p_rng,
1170 const unsigned char *label, size_t label_len,
1171 size_t ilen,
1172 const unsigned char *input,
1173 unsigned char *output )
1174 {
1175 size_t olen;
1176 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
1177 unsigned char *p = output;
1178 unsigned int hlen;
1179 const mbedtls_md_info_t *md_info;
1180 mbedtls_md_context_t md_ctx;
1181
1182 RSA_VALIDATE_RET( ctx != NULL );
1183 RSA_VALIDATE_RET( output != NULL );
1184 RSA_VALIDATE_RET( ilen == 0 || input != NULL );
1185 RSA_VALIDATE_RET( label_len == 0 || label != NULL );
1186
1187 if( f_rng == NULL )
1188 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1189
1190 md_info = mbedtls_md_info_from_type( (mbedtls_md_type_t) ctx->hash_id );
1191 if( md_info == NULL )
1192 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1193
1194 olen = ctx->len;
1195 hlen = mbedtls_md_get_size( md_info );
1196
1197 /* first comparison checks for overflow */
1198 if( ilen + 2 * hlen + 2 < ilen || olen < ilen + 2 * hlen + 2 )
1199 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1200
1201 memset( output, 0, olen );
1202
1203 *p++ = 0;
1204
1205 /* Generate a random octet string seed */
1206 if( ( ret = f_rng( p_rng, p, hlen ) ) != 0 )
1207 return( MBEDTLS_ERROR_ADD( MBEDTLS_ERR_RSA_RNG_FAILED, ret ) );
1208
1209 p += hlen;
1210
1211 /* Construct DB */
1212 if( ( ret = mbedtls_md( md_info, label, label_len, p ) ) != 0 )
1213 return( ret );
1214 p += hlen;
1215 p += olen - 2 * hlen - 2 - ilen;
1216 *p++ = 1;
1217 if( ilen != 0 )
1218 memcpy( p, input, ilen );
1219
1220 mbedtls_md_init( &md_ctx );
1221 if( ( ret = mbedtls_md_setup( &md_ctx, md_info, 0 ) ) != 0 )
1222 goto exit;
1223
1224 /* maskedDB: Apply dbMask to DB */
1225 if( ( ret = mgf_mask( output + hlen + 1, olen - hlen - 1, output + 1, hlen,
1226 &md_ctx ) ) != 0 )
1227 goto exit;
1228
1229 /* maskedSeed: Apply seedMask to seed */
1230 if( ( ret = mgf_mask( output + 1, hlen, output + hlen + 1, olen - hlen - 1,
1231 &md_ctx ) ) != 0 )
1232 goto exit;
1233
1234 exit:
1235 mbedtls_md_free( &md_ctx );
1236
1237 if( ret != 0 )
1238 return( ret );
1239
1240 return( mbedtls_rsa_public( ctx, output, output ) );
1241 }
1242 #endif /* MBEDTLS_PKCS1_V21 */
1243
1244 #if defined(MBEDTLS_PKCS1_V15)
1245 /*
1246 * Implementation of the PKCS#1 v2.1 RSAES-PKCS1-V1_5-ENCRYPT function
1247 */
mbedtls_rsa_rsaes_pkcs1_v15_encrypt(mbedtls_rsa_context * ctx,int (* f_rng)(void *,unsigned char *,size_t),void * p_rng,size_t ilen,const unsigned char * input,unsigned char * output)1248 int mbedtls_rsa_rsaes_pkcs1_v15_encrypt( mbedtls_rsa_context *ctx,
1249 int (*f_rng)(void *, unsigned char *, size_t),
1250 void *p_rng, size_t ilen,
1251 const unsigned char *input,
1252 unsigned char *output )
1253 {
1254 size_t nb_pad, olen;
1255 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
1256 unsigned char *p = output;
1257
1258 RSA_VALIDATE_RET( ctx != NULL );
1259 RSA_VALIDATE_RET( output != NULL );
1260 RSA_VALIDATE_RET( ilen == 0 || input != NULL );
1261
1262 olen = ctx->len;
1263
1264 /* first comparison checks for overflow */
1265 if( ilen + 11 < ilen || olen < ilen + 11 )
1266 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1267
1268 nb_pad = olen - 3 - ilen;
1269
1270 *p++ = 0;
1271
1272 if( f_rng == NULL )
1273 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1274
1275 *p++ = MBEDTLS_RSA_CRYPT;
1276
1277 while( nb_pad-- > 0 )
1278 {
1279 int rng_dl = 100;
1280
1281 do {
1282 ret = f_rng( p_rng, p, 1 );
1283 } while( *p == 0 && --rng_dl && ret == 0 );
1284
1285 /* Check if RNG failed to generate data */
1286 if( rng_dl == 0 || ret != 0 )
1287 return( MBEDTLS_ERROR_ADD( MBEDTLS_ERR_RSA_RNG_FAILED, ret ) );
1288
1289 p++;
1290 }
1291
1292 *p++ = 0;
1293 if( ilen != 0 )
1294 memcpy( p, input, ilen );
1295
1296 return( mbedtls_rsa_public( ctx, output, output ) );
1297 }
1298 #endif /* MBEDTLS_PKCS1_V15 */
1299
1300 /*
1301 * Add the message padding, then do an RSA operation
1302 */
mbedtls_rsa_pkcs1_encrypt(mbedtls_rsa_context * ctx,int (* f_rng)(void *,unsigned char *,size_t),void * p_rng,size_t ilen,const unsigned char * input,unsigned char * output)1303 int mbedtls_rsa_pkcs1_encrypt( mbedtls_rsa_context *ctx,
1304 int (*f_rng)(void *, unsigned char *, size_t),
1305 void *p_rng,
1306 size_t ilen,
1307 const unsigned char *input,
1308 unsigned char *output )
1309 {
1310 RSA_VALIDATE_RET( ctx != NULL );
1311 RSA_VALIDATE_RET( output != NULL );
1312 RSA_VALIDATE_RET( ilen == 0 || input != NULL );
1313
1314 switch( ctx->padding )
1315 {
1316 #if defined(MBEDTLS_PKCS1_V15)
1317 case MBEDTLS_RSA_PKCS_V15:
1318 return mbedtls_rsa_rsaes_pkcs1_v15_encrypt( ctx, f_rng, p_rng,
1319 ilen, input, output );
1320 #endif
1321
1322 #if defined(MBEDTLS_PKCS1_V21)
1323 case MBEDTLS_RSA_PKCS_V21:
1324 return mbedtls_rsa_rsaes_oaep_encrypt( ctx, f_rng, p_rng, NULL, 0,
1325 ilen, input, output );
1326 #endif
1327
1328 default:
1329 return( MBEDTLS_ERR_RSA_INVALID_PADDING );
1330 }
1331 }
1332
1333 #if defined(MBEDTLS_PKCS1_V21)
1334 /*
1335 * Implementation of the PKCS#1 v2.1 RSAES-OAEP-DECRYPT function
1336 */
mbedtls_rsa_rsaes_oaep_decrypt(mbedtls_rsa_context * ctx,int (* f_rng)(void *,unsigned char *,size_t),void * p_rng,const unsigned char * label,size_t label_len,size_t * olen,const unsigned char * input,unsigned char * output,size_t output_max_len)1337 int mbedtls_rsa_rsaes_oaep_decrypt( mbedtls_rsa_context *ctx,
1338 int (*f_rng)(void *, unsigned char *, size_t),
1339 void *p_rng,
1340 const unsigned char *label, size_t label_len,
1341 size_t *olen,
1342 const unsigned char *input,
1343 unsigned char *output,
1344 size_t output_max_len )
1345 {
1346 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
1347 size_t ilen, i, pad_len;
1348 unsigned char *p, bad, pad_done;
1349 unsigned char buf[MBEDTLS_MPI_MAX_SIZE];
1350 unsigned char lhash[MBEDTLS_MD_MAX_SIZE];
1351 unsigned int hlen;
1352 const mbedtls_md_info_t *md_info;
1353 mbedtls_md_context_t md_ctx;
1354
1355 RSA_VALIDATE_RET( ctx != NULL );
1356 RSA_VALIDATE_RET( output_max_len == 0 || output != NULL );
1357 RSA_VALIDATE_RET( label_len == 0 || label != NULL );
1358 RSA_VALIDATE_RET( input != NULL );
1359 RSA_VALIDATE_RET( olen != NULL );
1360
1361 /*
1362 * Parameters sanity checks
1363 */
1364 if( ctx->padding != MBEDTLS_RSA_PKCS_V21 )
1365 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1366
1367 ilen = ctx->len;
1368
1369 if( ilen < 16 || ilen > sizeof( buf ) )
1370 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1371
1372 md_info = mbedtls_md_info_from_type( (mbedtls_md_type_t) ctx->hash_id );
1373 if( md_info == NULL )
1374 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1375
1376 hlen = mbedtls_md_get_size( md_info );
1377
1378 // checking for integer underflow
1379 if( 2 * hlen + 2 > ilen )
1380 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1381
1382 /*
1383 * RSA operation
1384 */
1385 ret = mbedtls_rsa_private( ctx, f_rng, p_rng, input, buf );
1386
1387 if( ret != 0 )
1388 goto cleanup;
1389
1390 /*
1391 * Unmask data and generate lHash
1392 */
1393 mbedtls_md_init( &md_ctx );
1394 if( ( ret = mbedtls_md_setup( &md_ctx, md_info, 0 ) ) != 0 )
1395 {
1396 mbedtls_md_free( &md_ctx );
1397 goto cleanup;
1398 }
1399
1400 /* seed: Apply seedMask to maskedSeed */
1401 if( ( ret = mgf_mask( buf + 1, hlen, buf + hlen + 1, ilen - hlen - 1,
1402 &md_ctx ) ) != 0 ||
1403 /* DB: Apply dbMask to maskedDB */
1404 ( ret = mgf_mask( buf + hlen + 1, ilen - hlen - 1, buf + 1, hlen,
1405 &md_ctx ) ) != 0 )
1406 {
1407 mbedtls_md_free( &md_ctx );
1408 goto cleanup;
1409 }
1410
1411 mbedtls_md_free( &md_ctx );
1412
1413 /* Generate lHash */
1414 if( ( ret = mbedtls_md( md_info, label, label_len, lhash ) ) != 0 )
1415 goto cleanup;
1416
1417 /*
1418 * Check contents, in "constant-time"
1419 */
1420 p = buf;
1421 bad = 0;
1422
1423 bad |= *p++; /* First byte must be 0 */
1424
1425 p += hlen; /* Skip seed */
1426
1427 /* Check lHash */
1428 for( i = 0; i < hlen; i++ )
1429 bad |= lhash[i] ^ *p++;
1430
1431 /* Get zero-padding len, but always read till end of buffer
1432 * (minus one, for the 01 byte) */
1433 pad_len = 0;
1434 pad_done = 0;
1435 for( i = 0; i < ilen - 2 * hlen - 2; i++ )
1436 {
1437 pad_done |= p[i];
1438 pad_len += ((pad_done | (unsigned char)-pad_done) >> 7) ^ 1;
1439 }
1440
1441 p += pad_len;
1442 bad |= *p++ ^ 0x01;
1443
1444 /*
1445 * The only information "leaked" is whether the padding was correct or not
1446 * (eg, no data is copied if it was not correct). This meets the
1447 * recommendations in PKCS#1 v2.2: an opponent cannot distinguish between
1448 * the different error conditions.
1449 */
1450 if( bad != 0 )
1451 {
1452 ret = MBEDTLS_ERR_RSA_INVALID_PADDING;
1453 goto cleanup;
1454 }
1455
1456 if( ilen - ( p - buf ) > output_max_len )
1457 {
1458 ret = MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE;
1459 goto cleanup;
1460 }
1461
1462 *olen = ilen - (p - buf);
1463 if( *olen != 0 )
1464 memcpy( output, p, *olen );
1465 ret = 0;
1466
1467 cleanup:
1468 mbedtls_platform_zeroize( buf, sizeof( buf ) );
1469 mbedtls_platform_zeroize( lhash, sizeof( lhash ) );
1470
1471 return( ret );
1472 }
1473 #endif /* MBEDTLS_PKCS1_V21 */
1474
1475 #if defined(MBEDTLS_PKCS1_V15)
1476 /** Turn zero-or-nonzero into zero-or-all-bits-one, without branches.
1477 *
1478 * \param value The value to analyze.
1479 * \return Zero if \p value is zero, otherwise all-bits-one.
1480 */
all_or_nothing_int(unsigned value)1481 static unsigned all_or_nothing_int( unsigned value )
1482 {
1483 /* MSVC has a warning about unary minus on unsigned, but this is
1484 * well-defined and precisely what we want to do here */
1485 #if defined(_MSC_VER)
1486 #pragma warning( push )
1487 #pragma warning( disable : 4146 )
1488 #endif
1489 return( - ( ( value | - value ) >> ( sizeof( value ) * 8 - 1 ) ) );
1490 #if defined(_MSC_VER)
1491 #pragma warning( pop )
1492 #endif
1493 }
1494
1495 /** Check whether a size is out of bounds, without branches.
1496 *
1497 * This is equivalent to `size > max`, but is likely to be compiled to
1498 * to code using bitwise operation rather than a branch.
1499 *
1500 * \param size Size to check.
1501 * \param max Maximum desired value for \p size.
1502 * \return \c 0 if `size <= max`.
1503 * \return \c 1 if `size > max`.
1504 */
size_greater_than(size_t size,size_t max)1505 static unsigned size_greater_than( size_t size, size_t max )
1506 {
1507 /* Return the sign bit (1 for negative) of (max - size). */
1508 return( ( max - size ) >> ( sizeof( size_t ) * 8 - 1 ) );
1509 }
1510
1511 /** Choose between two integer values, without branches.
1512 *
1513 * This is equivalent to `cond ? if1 : if0`, but is likely to be compiled
1514 * to code using bitwise operation rather than a branch.
1515 *
1516 * \param cond Condition to test.
1517 * \param if1 Value to use if \p cond is nonzero.
1518 * \param if0 Value to use if \p cond is zero.
1519 * \return \c if1 if \p cond is nonzero, otherwise \c if0.
1520 */
if_int(unsigned cond,unsigned if1,unsigned if0)1521 static unsigned if_int( unsigned cond, unsigned if1, unsigned if0 )
1522 {
1523 unsigned mask = all_or_nothing_int( cond );
1524 return( ( mask & if1 ) | (~mask & if0 ) );
1525 }
1526
1527 /** Shift some data towards the left inside a buffer without leaking
1528 * the length of the data through side channels.
1529 *
1530 * `mem_move_to_left(start, total, offset)` is functionally equivalent to
1531 * ```
1532 * memmove(start, start + offset, total - offset);
1533 * memset(start + offset, 0, total - offset);
1534 * ```
1535 * but it strives to use a memory access pattern (and thus total timing)
1536 * that does not depend on \p offset. This timing independence comes at
1537 * the expense of performance.
1538 *
1539 * \param start Pointer to the start of the buffer.
1540 * \param total Total size of the buffer.
1541 * \param offset Offset from which to copy \p total - \p offset bytes.
1542 */
mem_move_to_left(void * start,size_t total,size_t offset)1543 static void mem_move_to_left( void *start,
1544 size_t total,
1545 size_t offset )
1546 {
1547 volatile unsigned char *buf = start;
1548 size_t i, n;
1549 if( total == 0 )
1550 return;
1551 for( i = 0; i < total; i++ )
1552 {
1553 unsigned no_op = size_greater_than( total - offset, i );
1554 /* The first `total - offset` passes are a no-op. The last
1555 * `offset` passes shift the data one byte to the left and
1556 * zero out the last byte. */
1557 for( n = 0; n < total - 1; n++ )
1558 {
1559 unsigned char current = buf[n];
1560 unsigned char next = buf[n+1];
1561 buf[n] = if_int( no_op, current, next );
1562 }
1563 buf[total-1] = if_int( no_op, buf[total-1], 0 );
1564 }
1565 }
1566
1567 /*
1568 * Implementation of the PKCS#1 v2.1 RSAES-PKCS1-V1_5-DECRYPT function
1569 */
mbedtls_rsa_rsaes_pkcs1_v15_decrypt(mbedtls_rsa_context * ctx,int (* f_rng)(void *,unsigned char *,size_t),void * p_rng,size_t * olen,const unsigned char * input,unsigned char * output,size_t output_max_len)1570 int mbedtls_rsa_rsaes_pkcs1_v15_decrypt( mbedtls_rsa_context *ctx,
1571 int (*f_rng)(void *, unsigned char *, size_t),
1572 void *p_rng,
1573 size_t *olen,
1574 const unsigned char *input,
1575 unsigned char *output,
1576 size_t output_max_len )
1577 {
1578 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
1579 size_t ilen, i, plaintext_max_size;
1580 unsigned char buf[MBEDTLS_MPI_MAX_SIZE];
1581 /* The following variables take sensitive values: their value must
1582 * not leak into the observable behavior of the function other than
1583 * the designated outputs (output, olen, return value). Otherwise
1584 * this would open the execution of the function to
1585 * side-channel-based variants of the Bleichenbacher padding oracle
1586 * attack. Potential side channels include overall timing, memory
1587 * access patterns (especially visible to an adversary who has access
1588 * to a shared memory cache), and branches (especially visible to
1589 * an adversary who has access to a shared code cache or to a shared
1590 * branch predictor). */
1591 size_t pad_count = 0;
1592 unsigned bad = 0;
1593 unsigned char pad_done = 0;
1594 size_t plaintext_size = 0;
1595 unsigned output_too_large;
1596
1597 RSA_VALIDATE_RET( ctx != NULL );
1598 RSA_VALIDATE_RET( output_max_len == 0 || output != NULL );
1599 RSA_VALIDATE_RET( input != NULL );
1600 RSA_VALIDATE_RET( olen != NULL );
1601
1602 ilen = ctx->len;
1603 plaintext_max_size = ( output_max_len > ilen - 11 ?
1604 ilen - 11 :
1605 output_max_len );
1606
1607 if( ctx->padding != MBEDTLS_RSA_PKCS_V15 )
1608 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1609
1610 if( ilen < 16 || ilen > sizeof( buf ) )
1611 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1612
1613 ret = mbedtls_rsa_private( ctx, f_rng, p_rng, input, buf );
1614
1615 if( ret != 0 )
1616 goto cleanup;
1617
1618 /* Check and get padding length in constant time and constant
1619 * memory trace. The first byte must be 0. */
1620 bad |= buf[0];
1621
1622
1623 /* Decode EME-PKCS1-v1_5 padding: 0x00 || 0x02 || PS || 0x00
1624 * where PS must be at least 8 nonzero bytes. */
1625 bad |= buf[1] ^ MBEDTLS_RSA_CRYPT;
1626
1627 /* Read the whole buffer. Set pad_done to nonzero if we find
1628 * the 0x00 byte and remember the padding length in pad_count. */
1629 for( i = 2; i < ilen; i++ )
1630 {
1631 pad_done |= ((buf[i] | (unsigned char)-buf[i]) >> 7) ^ 1;
1632 pad_count += ((pad_done | (unsigned char)-pad_done) >> 7) ^ 1;
1633 }
1634
1635
1636 /* If pad_done is still zero, there's no data, only unfinished padding. */
1637 bad |= if_int( pad_done, 0, 1 );
1638
1639 /* There must be at least 8 bytes of padding. */
1640 bad |= size_greater_than( 8, pad_count );
1641
1642 /* If the padding is valid, set plaintext_size to the number of
1643 * remaining bytes after stripping the padding. If the padding
1644 * is invalid, avoid leaking this fact through the size of the
1645 * output: use the maximum message size that fits in the output
1646 * buffer. Do it without branches to avoid leaking the padding
1647 * validity through timing. RSA keys are small enough that all the
1648 * size_t values involved fit in unsigned int. */
1649 plaintext_size = if_int( bad,
1650 (unsigned) plaintext_max_size,
1651 (unsigned) ( ilen - pad_count - 3 ) );
1652
1653 /* Set output_too_large to 0 if the plaintext fits in the output
1654 * buffer and to 1 otherwise. */
1655 output_too_large = size_greater_than( plaintext_size,
1656 plaintext_max_size );
1657
1658 /* Set ret without branches to avoid timing attacks. Return:
1659 * - INVALID_PADDING if the padding is bad (bad != 0).
1660 * - OUTPUT_TOO_LARGE if the padding is good but the decrypted
1661 * plaintext does not fit in the output buffer.
1662 * - 0 if the padding is correct. */
1663 ret = - (int) if_int( bad, - MBEDTLS_ERR_RSA_INVALID_PADDING,
1664 if_int( output_too_large, - MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE,
1665 0 ) );
1666
1667 /* If the padding is bad or the plaintext is too large, zero the
1668 * data that we're about to copy to the output buffer.
1669 * We need to copy the same amount of data
1670 * from the same buffer whether the padding is good or not to
1671 * avoid leaking the padding validity through overall timing or
1672 * through memory or cache access patterns. */
1673 bad = all_or_nothing_int( bad | output_too_large );
1674 for( i = 11; i < ilen; i++ )
1675 buf[i] &= ~bad;
1676
1677 /* If the plaintext is too large, truncate it to the buffer size.
1678 * Copy anyway to avoid revealing the length through timing, because
1679 * revealing the length is as bad as revealing the padding validity
1680 * for a Bleichenbacher attack. */
1681 plaintext_size = if_int( output_too_large,
1682 (unsigned) plaintext_max_size,
1683 (unsigned) plaintext_size );
1684
1685 /* Move the plaintext to the leftmost position where it can start in
1686 * the working buffer, i.e. make it start plaintext_max_size from
1687 * the end of the buffer. Do this with a memory access trace that
1688 * does not depend on the plaintext size. After this move, the
1689 * starting location of the plaintext is no longer sensitive
1690 * information. */
1691 mem_move_to_left( buf + ilen - plaintext_max_size,
1692 plaintext_max_size,
1693 plaintext_max_size - plaintext_size );
1694
1695 /* Finally copy the decrypted plaintext plus trailing zeros into the output
1696 * buffer. If output_max_len is 0, then output may be an invalid pointer
1697 * and the result of memcpy() would be undefined; prevent undefined
1698 * behavior making sure to depend only on output_max_len (the size of the
1699 * user-provided output buffer), which is independent from plaintext
1700 * length, validity of padding, success of the decryption, and other
1701 * secrets. */
1702 if( output_max_len != 0 )
1703 memcpy( output, buf + ilen - plaintext_max_size, plaintext_max_size );
1704
1705 /* Report the amount of data we copied to the output buffer. In case
1706 * of errors (bad padding or output too large), the value of *olen
1707 * when this function returns is not specified. Making it equivalent
1708 * to the good case limits the risks of leaking the padding validity. */
1709 *olen = plaintext_size;
1710
1711 cleanup:
1712 mbedtls_platform_zeroize( buf, sizeof( buf ) );
1713
1714 return( ret );
1715 }
1716 #endif /* MBEDTLS_PKCS1_V15 */
1717
1718 /*
1719 * Do an RSA operation, then remove the message padding
1720 */
mbedtls_rsa_pkcs1_decrypt(mbedtls_rsa_context * ctx,int (* f_rng)(void *,unsigned char *,size_t),void * p_rng,size_t * olen,const unsigned char * input,unsigned char * output,size_t output_max_len)1721 int mbedtls_rsa_pkcs1_decrypt( mbedtls_rsa_context *ctx,
1722 int (*f_rng)(void *, unsigned char *, size_t),
1723 void *p_rng,
1724 size_t *olen,
1725 const unsigned char *input,
1726 unsigned char *output,
1727 size_t output_max_len)
1728 {
1729 RSA_VALIDATE_RET( ctx != NULL );
1730 RSA_VALIDATE_RET( output_max_len == 0 || output != NULL );
1731 RSA_VALIDATE_RET( input != NULL );
1732 RSA_VALIDATE_RET( olen != NULL );
1733
1734 switch( ctx->padding )
1735 {
1736 #if defined(MBEDTLS_PKCS1_V15)
1737 case MBEDTLS_RSA_PKCS_V15:
1738 return mbedtls_rsa_rsaes_pkcs1_v15_decrypt( ctx, f_rng, p_rng, olen,
1739 input, output, output_max_len );
1740 #endif
1741
1742 #if defined(MBEDTLS_PKCS1_V21)
1743 case MBEDTLS_RSA_PKCS_V21:
1744 return mbedtls_rsa_rsaes_oaep_decrypt( ctx, f_rng, p_rng, NULL, 0,
1745 olen, input, output,
1746 output_max_len );
1747 #endif
1748
1749 default:
1750 return( MBEDTLS_ERR_RSA_INVALID_PADDING );
1751 }
1752 }
1753
1754 #if defined(MBEDTLS_PKCS1_V21)
rsa_rsassa_pss_sign(mbedtls_rsa_context * ctx,int (* f_rng)(void *,unsigned char *,size_t),void * p_rng,mbedtls_md_type_t md_alg,unsigned int hashlen,const unsigned char * hash,int saltlen,unsigned char * sig)1755 static int rsa_rsassa_pss_sign( mbedtls_rsa_context *ctx,
1756 int (*f_rng)(void *, unsigned char *, size_t),
1757 void *p_rng,
1758 mbedtls_md_type_t md_alg,
1759 unsigned int hashlen,
1760 const unsigned char *hash,
1761 int saltlen,
1762 unsigned char *sig )
1763 {
1764 size_t olen;
1765 unsigned char *p = sig;
1766 unsigned char *salt = NULL;
1767 size_t slen, min_slen, hlen, offset = 0;
1768 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
1769 size_t msb;
1770 const mbedtls_md_info_t *md_info;
1771 mbedtls_md_context_t md_ctx;
1772 RSA_VALIDATE_RET( ctx != NULL );
1773 RSA_VALIDATE_RET( ( md_alg == MBEDTLS_MD_NONE &&
1774 hashlen == 0 ) ||
1775 hash != NULL );
1776 RSA_VALIDATE_RET( sig != NULL );
1777
1778 if( ctx->padding != MBEDTLS_RSA_PKCS_V21 )
1779 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1780
1781 if( f_rng == NULL )
1782 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1783
1784 olen = ctx->len;
1785
1786 if( md_alg != MBEDTLS_MD_NONE )
1787 {
1788 /* Gather length of hash to sign */
1789 md_info = mbedtls_md_info_from_type( md_alg );
1790 if( md_info == NULL )
1791 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1792
1793 if( hashlen != mbedtls_md_get_size( md_info ) )
1794 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1795 }
1796
1797 md_info = mbedtls_md_info_from_type( (mbedtls_md_type_t) ctx->hash_id );
1798 if( md_info == NULL )
1799 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1800
1801 hlen = mbedtls_md_get_size( md_info );
1802
1803 if (saltlen == MBEDTLS_RSA_SALT_LEN_ANY)
1804 {
1805 /* Calculate the largest possible salt length, up to the hash size.
1806 * Normally this is the hash length, which is the maximum salt length
1807 * according to FIPS 185-4 §5.5 (e) and common practice. If there is not
1808 * enough room, use the maximum salt length that fits. The constraint is
1809 * that the hash length plus the salt length plus 2 bytes must be at most
1810 * the key length. This complies with FIPS 186-4 §5.5 (e) and RFC 8017
1811 * (PKCS#1 v2.2) §9.1.1 step 3. */
1812 min_slen = hlen - 2;
1813 if( olen < hlen + min_slen + 2 )
1814 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1815 else if( olen >= hlen + hlen + 2 )
1816 slen = hlen;
1817 else
1818 slen = olen - hlen - 2;
1819 }
1820 else if ( (saltlen < 0) || (saltlen + hlen + 2 > olen) )
1821 {
1822 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1823 }
1824 else
1825 {
1826 slen = (size_t) saltlen;
1827 }
1828
1829 memset( sig, 0, olen );
1830
1831 /* Note: EMSA-PSS encoding is over the length of N - 1 bits */
1832 msb = mbedtls_mpi_bitlen( &ctx->N ) - 1;
1833 p += olen - hlen - slen - 2;
1834 *p++ = 0x01;
1835
1836 /* Generate salt of length slen in place in the encoded message */
1837 salt = p;
1838 if( ( ret = f_rng( p_rng, salt, slen ) ) != 0 )
1839 return( MBEDTLS_ERROR_ADD( MBEDTLS_ERR_RSA_RNG_FAILED, ret ) );
1840
1841 p += slen;
1842
1843 mbedtls_md_init( &md_ctx );
1844 if( ( ret = mbedtls_md_setup( &md_ctx, md_info, 0 ) ) != 0 )
1845 goto exit;
1846
1847 /* Generate H = Hash( M' ) */
1848 if( ( ret = mbedtls_md_starts( &md_ctx ) ) != 0 )
1849 goto exit;
1850 if( ( ret = mbedtls_md_update( &md_ctx, p, 8 ) ) != 0 )
1851 goto exit;
1852 if( ( ret = mbedtls_md_update( &md_ctx, hash, hashlen ) ) != 0 )
1853 goto exit;
1854 if( ( ret = mbedtls_md_update( &md_ctx, salt, slen ) ) != 0 )
1855 goto exit;
1856 if( ( ret = mbedtls_md_finish( &md_ctx, p ) ) != 0 )
1857 goto exit;
1858
1859 /* Compensate for boundary condition when applying mask */
1860 if( msb % 8 == 0 )
1861 offset = 1;
1862
1863 /* maskedDB: Apply dbMask to DB */
1864 if( ( ret = mgf_mask( sig + offset, olen - hlen - 1 - offset, p, hlen,
1865 &md_ctx ) ) != 0 )
1866 goto exit;
1867
1868 msb = mbedtls_mpi_bitlen( &ctx->N ) - 1;
1869 sig[0] &= 0xFF >> ( olen * 8 - msb );
1870
1871 p += hlen;
1872 *p++ = 0xBC;
1873
1874 exit:
1875 mbedtls_md_free( &md_ctx );
1876
1877 if( ret != 0 )
1878 return( ret );
1879
1880 return mbedtls_rsa_private( ctx, f_rng, p_rng, sig, sig );
1881 }
1882
1883 /*
1884 * Implementation of the PKCS#1 v2.1 RSASSA-PSS-SIGN function with
1885 * the option to pass in the salt length.
1886 */
mbedtls_rsa_rsassa_pss_sign_ext(mbedtls_rsa_context * ctx,int (* f_rng)(void *,unsigned char *,size_t),void * p_rng,mbedtls_md_type_t md_alg,unsigned int hashlen,const unsigned char * hash,int saltlen,unsigned char * sig)1887 int mbedtls_rsa_rsassa_pss_sign_ext( mbedtls_rsa_context *ctx,
1888 int (*f_rng)(void *, unsigned char *, size_t),
1889 void *p_rng,
1890 mbedtls_md_type_t md_alg,
1891 unsigned int hashlen,
1892 const unsigned char *hash,
1893 int saltlen,
1894 unsigned char *sig )
1895 {
1896 return rsa_rsassa_pss_sign( ctx, f_rng, p_rng, md_alg,
1897 hashlen, hash, saltlen, sig );
1898 }
1899
1900
1901 /*
1902 * Implementation of the PKCS#1 v2.1 RSASSA-PSS-SIGN function
1903 */
mbedtls_rsa_rsassa_pss_sign(mbedtls_rsa_context * ctx,int (* f_rng)(void *,unsigned char *,size_t),void * p_rng,mbedtls_md_type_t md_alg,unsigned int hashlen,const unsigned char * hash,unsigned char * sig)1904 int mbedtls_rsa_rsassa_pss_sign( mbedtls_rsa_context *ctx,
1905 int (*f_rng)(void *, unsigned char *, size_t),
1906 void *p_rng,
1907 mbedtls_md_type_t md_alg,
1908 unsigned int hashlen,
1909 const unsigned char *hash,
1910 unsigned char *sig )
1911 {
1912 return rsa_rsassa_pss_sign( ctx, f_rng, p_rng, md_alg,
1913 hashlen, hash, MBEDTLS_RSA_SALT_LEN_ANY, sig );
1914 }
1915 #endif /* MBEDTLS_PKCS1_V21 */
1916
1917 #if defined(MBEDTLS_PKCS1_V15)
1918 /*
1919 * Implementation of the PKCS#1 v2.1 RSASSA-PKCS1-V1_5-SIGN function
1920 */
1921
1922 /* Construct a PKCS v1.5 encoding of a hashed message
1923 *
1924 * This is used both for signature generation and verification.
1925 *
1926 * Parameters:
1927 * - md_alg: Identifies the hash algorithm used to generate the given hash;
1928 * MBEDTLS_MD_NONE if raw data is signed.
1929 * - hashlen: Length of hash. Must match md_alg if that's not NONE.
1930 * - hash: Buffer containing the hashed message or the raw data.
1931 * - dst_len: Length of the encoded message.
1932 * - dst: Buffer to hold the encoded message.
1933 *
1934 * Assumptions:
1935 * - hash has size hashlen.
1936 * - dst points to a buffer of size at least dst_len.
1937 *
1938 */
rsa_rsassa_pkcs1_v15_encode(mbedtls_md_type_t md_alg,unsigned int hashlen,const unsigned char * hash,size_t dst_len,unsigned char * dst)1939 static int rsa_rsassa_pkcs1_v15_encode( mbedtls_md_type_t md_alg,
1940 unsigned int hashlen,
1941 const unsigned char *hash,
1942 size_t dst_len,
1943 unsigned char *dst )
1944 {
1945 size_t oid_size = 0;
1946 size_t nb_pad = dst_len;
1947 unsigned char *p = dst;
1948 const char *oid = NULL;
1949
1950 /* Are we signing hashed or raw data? */
1951 if( md_alg != MBEDTLS_MD_NONE )
1952 {
1953 const mbedtls_md_info_t *md_info = mbedtls_md_info_from_type( md_alg );
1954 if( md_info == NULL )
1955 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1956
1957 if( mbedtls_oid_get_oid_by_md( md_alg, &oid, &oid_size ) != 0 )
1958 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1959
1960 if( hashlen != mbedtls_md_get_size( md_info ) )
1961 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1962
1963 /* Double-check that 8 + hashlen + oid_size can be used as a
1964 * 1-byte ASN.1 length encoding and that there's no overflow. */
1965 if( 8 + hashlen + oid_size >= 0x80 ||
1966 10 + hashlen < hashlen ||
1967 10 + hashlen + oid_size < 10 + hashlen )
1968 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1969
1970 /*
1971 * Static bounds check:
1972 * - Need 10 bytes for five tag-length pairs.
1973 * (Insist on 1-byte length encodings to protect against variants of
1974 * Bleichenbacher's forgery attack against lax PKCS#1v1.5 verification)
1975 * - Need hashlen bytes for hash
1976 * - Need oid_size bytes for hash alg OID.
1977 */
1978 if( nb_pad < 10 + hashlen + oid_size )
1979 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1980 nb_pad -= 10 + hashlen + oid_size;
1981 }
1982 else
1983 {
1984 if( nb_pad < hashlen )
1985 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1986
1987 nb_pad -= hashlen;
1988 }
1989
1990 /* Need space for signature header and padding delimiter (3 bytes),
1991 * and 8 bytes for the minimal padding */
1992 if( nb_pad < 3 + 8 )
1993 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1994 nb_pad -= 3;
1995
1996 /* Now nb_pad is the amount of memory to be filled
1997 * with padding, and at least 8 bytes long. */
1998
1999 /* Write signature header and padding */
2000 *p++ = 0;
2001 *p++ = MBEDTLS_RSA_SIGN;
2002 memset( p, 0xFF, nb_pad );
2003 p += nb_pad;
2004 *p++ = 0;
2005
2006 /* Are we signing raw data? */
2007 if( md_alg == MBEDTLS_MD_NONE )
2008 {
2009 memcpy( p, hash, hashlen );
2010 return( 0 );
2011 }
2012
2013 /* Signing hashed data, add corresponding ASN.1 structure
2014 *
2015 * DigestInfo ::= SEQUENCE {
2016 * digestAlgorithm DigestAlgorithmIdentifier,
2017 * digest Digest }
2018 * DigestAlgorithmIdentifier ::= AlgorithmIdentifier
2019 * Digest ::= OCTET STRING
2020 *
2021 * Schematic:
2022 * TAG-SEQ + LEN [ TAG-SEQ + LEN [ TAG-OID + LEN [ OID ]
2023 * TAG-NULL + LEN [ NULL ] ]
2024 * TAG-OCTET + LEN [ HASH ] ]
2025 */
2026 *p++ = MBEDTLS_ASN1_SEQUENCE | MBEDTLS_ASN1_CONSTRUCTED;
2027 *p++ = (unsigned char)( 0x08 + oid_size + hashlen );
2028 *p++ = MBEDTLS_ASN1_SEQUENCE | MBEDTLS_ASN1_CONSTRUCTED;
2029 *p++ = (unsigned char)( 0x04 + oid_size );
2030 *p++ = MBEDTLS_ASN1_OID;
2031 *p++ = (unsigned char) oid_size;
2032 memcpy( p, oid, oid_size );
2033 p += oid_size;
2034 *p++ = MBEDTLS_ASN1_NULL;
2035 *p++ = 0x00;
2036 *p++ = MBEDTLS_ASN1_OCTET_STRING;
2037 *p++ = (unsigned char) hashlen;
2038 memcpy( p, hash, hashlen );
2039 p += hashlen;
2040
2041 /* Just a sanity-check, should be automatic
2042 * after the initial bounds check. */
2043 if( p != dst + dst_len )
2044 {
2045 mbedtls_platform_zeroize( dst, dst_len );
2046 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
2047 }
2048
2049 return( 0 );
2050 }
2051
2052 /*
2053 * Do an RSA operation to sign the message digest
2054 */
mbedtls_rsa_rsassa_pkcs1_v15_sign(mbedtls_rsa_context * ctx,int (* f_rng)(void *,unsigned char *,size_t),void * p_rng,mbedtls_md_type_t md_alg,unsigned int hashlen,const unsigned char * hash,unsigned char * sig)2055 int mbedtls_rsa_rsassa_pkcs1_v15_sign( mbedtls_rsa_context *ctx,
2056 int (*f_rng)(void *, unsigned char *, size_t),
2057 void *p_rng,
2058 mbedtls_md_type_t md_alg,
2059 unsigned int hashlen,
2060 const unsigned char *hash,
2061 unsigned char *sig )
2062 {
2063 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
2064 unsigned char *sig_try = NULL, *verif = NULL;
2065
2066 RSA_VALIDATE_RET( ctx != NULL );
2067 RSA_VALIDATE_RET( ( md_alg == MBEDTLS_MD_NONE &&
2068 hashlen == 0 ) ||
2069 hash != NULL );
2070 RSA_VALIDATE_RET( sig != NULL );
2071
2072 if( ctx->padding != MBEDTLS_RSA_PKCS_V15 )
2073 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
2074
2075 /*
2076 * Prepare PKCS1-v1.5 encoding (padding and hash identifier)
2077 */
2078
2079 if( ( ret = rsa_rsassa_pkcs1_v15_encode( md_alg, hashlen, hash,
2080 ctx->len, sig ) ) != 0 )
2081 return( ret );
2082
2083 /* Private key operation
2084 *
2085 * In order to prevent Lenstra's attack, make the signature in a
2086 * temporary buffer and check it before returning it.
2087 */
2088
2089 sig_try = mbedtls_calloc( 1, ctx->len );
2090 if( sig_try == NULL )
2091 return( MBEDTLS_ERR_MPI_ALLOC_FAILED );
2092
2093 verif = mbedtls_calloc( 1, ctx->len );
2094 if( verif == NULL )
2095 {
2096 mbedtls_free( sig_try );
2097 return( MBEDTLS_ERR_MPI_ALLOC_FAILED );
2098 }
2099
2100 MBEDTLS_MPI_CHK( mbedtls_rsa_private( ctx, f_rng, p_rng, sig, sig_try ) );
2101 MBEDTLS_MPI_CHK( mbedtls_rsa_public( ctx, sig_try, verif ) );
2102
2103 if( mbedtls_safer_memcmp( verif, sig, ctx->len ) != 0 )
2104 {
2105 ret = MBEDTLS_ERR_RSA_PRIVATE_FAILED;
2106 goto cleanup;
2107 }
2108
2109 memcpy( sig, sig_try, ctx->len );
2110
2111 cleanup:
2112 mbedtls_free( sig_try );
2113 mbedtls_free( verif );
2114
2115 return( ret );
2116 }
2117 #endif /* MBEDTLS_PKCS1_V15 */
2118
2119 /*
2120 * Do an RSA operation to sign the message digest
2121 */
mbedtls_rsa_pkcs1_sign(mbedtls_rsa_context * ctx,int (* f_rng)(void *,unsigned char *,size_t),void * p_rng,mbedtls_md_type_t md_alg,unsigned int hashlen,const unsigned char * hash,unsigned char * sig)2122 int mbedtls_rsa_pkcs1_sign( mbedtls_rsa_context *ctx,
2123 int (*f_rng)(void *, unsigned char *, size_t),
2124 void *p_rng,
2125 mbedtls_md_type_t md_alg,
2126 unsigned int hashlen,
2127 const unsigned char *hash,
2128 unsigned char *sig )
2129 {
2130 RSA_VALIDATE_RET( ctx != NULL );
2131 RSA_VALIDATE_RET( ( md_alg == MBEDTLS_MD_NONE &&
2132 hashlen == 0 ) ||
2133 hash != NULL );
2134 RSA_VALIDATE_RET( sig != NULL );
2135
2136 switch( ctx->padding )
2137 {
2138 #if defined(MBEDTLS_PKCS1_V15)
2139 case MBEDTLS_RSA_PKCS_V15:
2140 return mbedtls_rsa_rsassa_pkcs1_v15_sign( ctx, f_rng, p_rng,
2141 md_alg, hashlen, hash, sig );
2142 #endif
2143
2144 #if defined(MBEDTLS_PKCS1_V21)
2145 case MBEDTLS_RSA_PKCS_V21:
2146 return mbedtls_rsa_rsassa_pss_sign( ctx, f_rng, p_rng, md_alg,
2147 hashlen, hash, sig );
2148 #endif
2149
2150 default:
2151 return( MBEDTLS_ERR_RSA_INVALID_PADDING );
2152 }
2153 }
2154
2155 #if defined(MBEDTLS_PKCS1_V21)
2156 /*
2157 * Implementation of the PKCS#1 v2.1 RSASSA-PSS-VERIFY function
2158 */
mbedtls_rsa_rsassa_pss_verify_ext(mbedtls_rsa_context * ctx,mbedtls_md_type_t md_alg,unsigned int hashlen,const unsigned char * hash,mbedtls_md_type_t mgf1_hash_id,int expected_salt_len,const unsigned char * sig)2159 int mbedtls_rsa_rsassa_pss_verify_ext( mbedtls_rsa_context *ctx,
2160 mbedtls_md_type_t md_alg,
2161 unsigned int hashlen,
2162 const unsigned char *hash,
2163 mbedtls_md_type_t mgf1_hash_id,
2164 int expected_salt_len,
2165 const unsigned char *sig )
2166 {
2167 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
2168 size_t siglen;
2169 unsigned char *p;
2170 unsigned char *hash_start;
2171 unsigned char result[MBEDTLS_MD_MAX_SIZE];
2172 unsigned char zeros[8];
2173 unsigned int hlen;
2174 size_t observed_salt_len, msb;
2175 const mbedtls_md_info_t *md_info;
2176 mbedtls_md_context_t md_ctx;
2177 unsigned char buf[MBEDTLS_MPI_MAX_SIZE];
2178
2179 RSA_VALIDATE_RET( ctx != NULL );
2180 RSA_VALIDATE_RET( sig != NULL );
2181 RSA_VALIDATE_RET( ( md_alg == MBEDTLS_MD_NONE &&
2182 hashlen == 0 ) ||
2183 hash != NULL );
2184
2185 siglen = ctx->len;
2186
2187 if( siglen < 16 || siglen > sizeof( buf ) )
2188 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
2189
2190 ret = mbedtls_rsa_public( ctx, sig, buf );
2191
2192 if( ret != 0 )
2193 return( ret );
2194
2195 p = buf;
2196
2197 if( buf[siglen - 1] != 0xBC )
2198 return( MBEDTLS_ERR_RSA_INVALID_PADDING );
2199
2200 if( md_alg != MBEDTLS_MD_NONE )
2201 {
2202 /* Gather length of hash to sign */
2203 md_info = mbedtls_md_info_from_type( md_alg );
2204 if( md_info == NULL )
2205 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
2206
2207 if( hashlen != mbedtls_md_get_size( md_info ) )
2208 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
2209 }
2210
2211 md_info = mbedtls_md_info_from_type( mgf1_hash_id );
2212 if( md_info == NULL )
2213 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
2214
2215 hlen = mbedtls_md_get_size( md_info );
2216
2217 memset( zeros, 0, 8 );
2218
2219 /*
2220 * Note: EMSA-PSS verification is over the length of N - 1 bits
2221 */
2222 msb = mbedtls_mpi_bitlen( &ctx->N ) - 1;
2223
2224 if( buf[0] >> ( 8 - siglen * 8 + msb ) )
2225 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
2226
2227 /* Compensate for boundary condition when applying mask */
2228 if( msb % 8 == 0 )
2229 {
2230 p++;
2231 siglen -= 1;
2232 }
2233
2234 if( siglen < hlen + 2 )
2235 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
2236 hash_start = p + siglen - hlen - 1;
2237
2238 mbedtls_md_init( &md_ctx );
2239 if( ( ret = mbedtls_md_setup( &md_ctx, md_info, 0 ) ) != 0 )
2240 goto exit;
2241
2242 ret = mgf_mask( p, siglen - hlen - 1, hash_start, hlen, &md_ctx );
2243 if( ret != 0 )
2244 goto exit;
2245
2246 buf[0] &= 0xFF >> ( siglen * 8 - msb );
2247
2248 while( p < hash_start - 1 && *p == 0 )
2249 p++;
2250
2251 if( *p++ != 0x01 )
2252 {
2253 ret = MBEDTLS_ERR_RSA_INVALID_PADDING;
2254 goto exit;
2255 }
2256
2257 observed_salt_len = hash_start - p;
2258
2259 if( expected_salt_len != MBEDTLS_RSA_SALT_LEN_ANY &&
2260 observed_salt_len != (size_t) expected_salt_len )
2261 {
2262 ret = MBEDTLS_ERR_RSA_INVALID_PADDING;
2263 goto exit;
2264 }
2265
2266 /*
2267 * Generate H = Hash( M' )
2268 */
2269 ret = mbedtls_md_starts( &md_ctx );
2270 if ( ret != 0 )
2271 goto exit;
2272 ret = mbedtls_md_update( &md_ctx, zeros, 8 );
2273 if ( ret != 0 )
2274 goto exit;
2275 ret = mbedtls_md_update( &md_ctx, hash, hashlen );
2276 if ( ret != 0 )
2277 goto exit;
2278 ret = mbedtls_md_update( &md_ctx, p, observed_salt_len );
2279 if ( ret != 0 )
2280 goto exit;
2281 ret = mbedtls_md_finish( &md_ctx, result );
2282 if ( ret != 0 )
2283 goto exit;
2284
2285 if( memcmp( hash_start, result, hlen ) != 0 )
2286 {
2287 ret = MBEDTLS_ERR_RSA_VERIFY_FAILED;
2288 goto exit;
2289 }
2290
2291 exit:
2292 mbedtls_md_free( &md_ctx );
2293
2294 return( ret );
2295 }
2296
2297 /*
2298 * Simplified PKCS#1 v2.1 RSASSA-PSS-VERIFY function
2299 */
mbedtls_rsa_rsassa_pss_verify(mbedtls_rsa_context * ctx,mbedtls_md_type_t md_alg,unsigned int hashlen,const unsigned char * hash,const unsigned char * sig)2300 int mbedtls_rsa_rsassa_pss_verify( mbedtls_rsa_context *ctx,
2301 mbedtls_md_type_t md_alg,
2302 unsigned int hashlen,
2303 const unsigned char *hash,
2304 const unsigned char *sig )
2305 {
2306 mbedtls_md_type_t mgf1_hash_id;
2307 RSA_VALIDATE_RET( ctx != NULL );
2308 RSA_VALIDATE_RET( sig != NULL );
2309 RSA_VALIDATE_RET( ( md_alg == MBEDTLS_MD_NONE &&
2310 hashlen == 0 ) ||
2311 hash != NULL );
2312
2313 mgf1_hash_id = ( ctx->hash_id != MBEDTLS_MD_NONE )
2314 ? (mbedtls_md_type_t) ctx->hash_id
2315 : md_alg;
2316
2317 return( mbedtls_rsa_rsassa_pss_verify_ext( ctx,
2318 md_alg, hashlen, hash,
2319 mgf1_hash_id,
2320 MBEDTLS_RSA_SALT_LEN_ANY,
2321 sig ) );
2322
2323 }
2324 #endif /* MBEDTLS_PKCS1_V21 */
2325
2326 #if defined(MBEDTLS_PKCS1_V15)
2327 /*
2328 * Implementation of the PKCS#1 v2.1 RSASSA-PKCS1-v1_5-VERIFY function
2329 */
mbedtls_rsa_rsassa_pkcs1_v15_verify(mbedtls_rsa_context * ctx,mbedtls_md_type_t md_alg,unsigned int hashlen,const unsigned char * hash,const unsigned char * sig)2330 int mbedtls_rsa_rsassa_pkcs1_v15_verify( mbedtls_rsa_context *ctx,
2331 mbedtls_md_type_t md_alg,
2332 unsigned int hashlen,
2333 const unsigned char *hash,
2334 const unsigned char *sig )
2335 {
2336 int ret = 0;
2337 size_t sig_len;
2338 unsigned char *encoded = NULL, *encoded_expected = NULL;
2339
2340 RSA_VALIDATE_RET( ctx != NULL );
2341 RSA_VALIDATE_RET( sig != NULL );
2342 RSA_VALIDATE_RET( ( md_alg == MBEDTLS_MD_NONE &&
2343 hashlen == 0 ) ||
2344 hash != NULL );
2345
2346 sig_len = ctx->len;
2347
2348 /*
2349 * Prepare expected PKCS1 v1.5 encoding of hash.
2350 */
2351
2352 if( ( encoded = mbedtls_calloc( 1, sig_len ) ) == NULL ||
2353 ( encoded_expected = mbedtls_calloc( 1, sig_len ) ) == NULL )
2354 {
2355 ret = MBEDTLS_ERR_MPI_ALLOC_FAILED;
2356 goto cleanup;
2357 }
2358
2359 if( ( ret = rsa_rsassa_pkcs1_v15_encode( md_alg, hashlen, hash, sig_len,
2360 encoded_expected ) ) != 0 )
2361 goto cleanup;
2362
2363 /*
2364 * Apply RSA primitive to get what should be PKCS1 encoded hash.
2365 */
2366
2367 ret = mbedtls_rsa_public( ctx, sig, encoded );
2368 if( ret != 0 )
2369 goto cleanup;
2370
2371 /*
2372 * Compare
2373 */
2374
2375 if( ( ret = mbedtls_safer_memcmp( encoded, encoded_expected,
2376 sig_len ) ) != 0 )
2377 {
2378 ret = MBEDTLS_ERR_RSA_VERIFY_FAILED;
2379 goto cleanup;
2380 }
2381
2382 cleanup:
2383
2384 if( encoded != NULL )
2385 {
2386 mbedtls_platform_zeroize( encoded, sig_len );
2387 mbedtls_free( encoded );
2388 }
2389
2390 if( encoded_expected != NULL )
2391 {
2392 mbedtls_platform_zeroize( encoded_expected, sig_len );
2393 mbedtls_free( encoded_expected );
2394 }
2395
2396 return( ret );
2397 }
2398 #endif /* MBEDTLS_PKCS1_V15 */
2399
2400 /*
2401 * Do an RSA operation and check the message digest
2402 */
mbedtls_rsa_pkcs1_verify(mbedtls_rsa_context * ctx,mbedtls_md_type_t md_alg,unsigned int hashlen,const unsigned char * hash,const unsigned char * sig)2403 int mbedtls_rsa_pkcs1_verify( mbedtls_rsa_context *ctx,
2404 mbedtls_md_type_t md_alg,
2405 unsigned int hashlen,
2406 const unsigned char *hash,
2407 const unsigned char *sig )
2408 {
2409 RSA_VALIDATE_RET( ctx != NULL );
2410 RSA_VALIDATE_RET( sig != NULL );
2411 RSA_VALIDATE_RET( ( md_alg == MBEDTLS_MD_NONE &&
2412 hashlen == 0 ) ||
2413 hash != NULL );
2414
2415 switch( ctx->padding )
2416 {
2417 #if defined(MBEDTLS_PKCS1_V15)
2418 case MBEDTLS_RSA_PKCS_V15:
2419 return mbedtls_rsa_rsassa_pkcs1_v15_verify( ctx, md_alg,
2420 hashlen, hash, sig );
2421 #endif
2422
2423 #if defined(MBEDTLS_PKCS1_V21)
2424 case MBEDTLS_RSA_PKCS_V21:
2425 return mbedtls_rsa_rsassa_pss_verify( ctx, md_alg,
2426 hashlen, hash, sig );
2427 #endif
2428
2429 default:
2430 return( MBEDTLS_ERR_RSA_INVALID_PADDING );
2431 }
2432 }
2433
2434 /*
2435 * Copy the components of an RSA key
2436 */
mbedtls_rsa_copy(mbedtls_rsa_context * dst,const mbedtls_rsa_context * src)2437 int mbedtls_rsa_copy( mbedtls_rsa_context *dst, const mbedtls_rsa_context *src )
2438 {
2439 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
2440 RSA_VALIDATE_RET( dst != NULL );
2441 RSA_VALIDATE_RET( src != NULL );
2442
2443 dst->len = src->len;
2444
2445 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &dst->N, &src->N ) );
2446 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &dst->E, &src->E ) );
2447
2448 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &dst->D, &src->D ) );
2449 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &dst->P, &src->P ) );
2450 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &dst->Q, &src->Q ) );
2451
2452 #if !defined(MBEDTLS_RSA_NO_CRT)
2453 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &dst->DP, &src->DP ) );
2454 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &dst->DQ, &src->DQ ) );
2455 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &dst->QP, &src->QP ) );
2456 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &dst->RP, &src->RP ) );
2457 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &dst->RQ, &src->RQ ) );
2458 #endif
2459
2460 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &dst->RN, &src->RN ) );
2461
2462 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &dst->Vi, &src->Vi ) );
2463 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &dst->Vf, &src->Vf ) );
2464
2465 dst->padding = src->padding;
2466 dst->hash_id = src->hash_id;
2467
2468 cleanup:
2469 if( ret != 0 )
2470 mbedtls_rsa_free( dst );
2471
2472 return( ret );
2473 }
2474
2475 /*
2476 * Free the components of an RSA key
2477 */
mbedtls_rsa_free(mbedtls_rsa_context * ctx)2478 void mbedtls_rsa_free( mbedtls_rsa_context *ctx )
2479 {
2480 if( ctx == NULL )
2481 return;
2482
2483 mbedtls_mpi_free( &ctx->Vi );
2484 mbedtls_mpi_free( &ctx->Vf );
2485 mbedtls_mpi_free( &ctx->RN );
2486 mbedtls_mpi_free( &ctx->D );
2487 mbedtls_mpi_free( &ctx->Q );
2488 mbedtls_mpi_free( &ctx->P );
2489 mbedtls_mpi_free( &ctx->E );
2490 mbedtls_mpi_free( &ctx->N );
2491
2492 #if !defined(MBEDTLS_RSA_NO_CRT)
2493 mbedtls_mpi_free( &ctx->RQ );
2494 mbedtls_mpi_free( &ctx->RP );
2495 mbedtls_mpi_free( &ctx->QP );
2496 mbedtls_mpi_free( &ctx->DQ );
2497 mbedtls_mpi_free( &ctx->DP );
2498 #endif /* MBEDTLS_RSA_NO_CRT */
2499
2500 #if defined(MBEDTLS_THREADING_C)
2501 /* Free the mutex, but only if it hasn't been freed already. */
2502 if( ctx->ver != 0 )
2503 {
2504 mbedtls_mutex_free( &ctx->mutex );
2505 ctx->ver = 0;
2506 }
2507 #endif
2508 }
2509
2510 #endif /* !MBEDTLS_RSA_ALT */
2511
2512 #if defined(MBEDTLS_SELF_TEST)
2513
2514 #include "mbedtls/sha1.h"
2515
2516 /*
2517 * Example RSA-1024 keypair, for test purposes
2518 */
2519 #define KEY_LEN 128
2520
2521 #define RSA_N "9292758453063D803DD603D5E777D788" \
2522 "8ED1D5BF35786190FA2F23EBC0848AEA" \
2523 "DDA92CA6C3D80B32C4D109BE0F36D6AE" \
2524 "7130B9CED7ACDF54CFC7555AC14EEBAB" \
2525 "93A89813FBF3C4F8066D2D800F7C38A8" \
2526 "1AE31942917403FF4946B0A83D3D3E05" \
2527 "EE57C6F5F5606FB5D4BC6CD34EE0801A" \
2528 "5E94BB77B07507233A0BC7BAC8F90F79"
2529
2530 #define RSA_E "10001"
2531
2532 #define RSA_D "24BF6185468786FDD303083D25E64EFC" \
2533 "66CA472BC44D253102F8B4A9D3BFA750" \
2534 "91386C0077937FE33FA3252D28855837" \
2535 "AE1B484A8A9A45F7EE8C0C634F99E8CD" \
2536 "DF79C5CE07EE72C7F123142198164234" \
2537 "CABB724CF78B8173B9F880FC86322407" \
2538 "AF1FEDFDDE2BEB674CA15F3E81A1521E" \
2539 "071513A1E85B5DFA031F21ECAE91A34D"
2540
2541 #define RSA_P "C36D0EB7FCD285223CFB5AABA5BDA3D8" \
2542 "2C01CAD19EA484A87EA4377637E75500" \
2543 "FCB2005C5C7DD6EC4AC023CDA285D796" \
2544 "C3D9E75E1EFC42488BB4F1D13AC30A57"
2545
2546 #define RSA_Q "C000DF51A7C77AE8D7C7370C1FF55B69" \
2547 "E211C2B9E5DB1ED0BF61D0D9899620F4" \
2548 "910E4168387E3C30AA1E00C339A79508" \
2549 "8452DD96A9A5EA5D9DCA68DA636032AF"
2550
2551 #define PT_LEN 24
2552 #define RSA_PT "\xAA\xBB\xCC\x03\x02\x01\x00\xFF\xFF\xFF\xFF\xFF" \
2553 "\x11\x22\x33\x0A\x0B\x0C\xCC\xDD\xDD\xDD\xDD\xDD"
2554
2555 #if defined(MBEDTLS_PKCS1_V15)
myrand(void * rng_state,unsigned char * output,size_t len)2556 static int myrand( void *rng_state, unsigned char *output, size_t len )
2557 {
2558 #if !defined(__OpenBSD__) && !defined(__NetBSD__)
2559 size_t i;
2560
2561 if( rng_state != NULL )
2562 rng_state = NULL;
2563
2564 for( i = 0; i < len; ++i )
2565 output[i] = rand();
2566 #else
2567 if( rng_state != NULL )
2568 rng_state = NULL;
2569
2570 arc4random_buf( output, len );
2571 #endif /* !OpenBSD && !NetBSD */
2572
2573 return( 0 );
2574 }
2575 #endif /* MBEDTLS_PKCS1_V15 */
2576
2577 /*
2578 * Checkup routine
2579 */
mbedtls_rsa_self_test(int verbose)2580 int mbedtls_rsa_self_test( int verbose )
2581 {
2582 int ret = 0;
2583 #if defined(MBEDTLS_PKCS1_V15)
2584 size_t len;
2585 mbedtls_rsa_context rsa;
2586 unsigned char rsa_plaintext[PT_LEN];
2587 unsigned char rsa_decrypted[PT_LEN];
2588 unsigned char rsa_ciphertext[KEY_LEN];
2589 #if defined(MBEDTLS_SHA1_C)
2590 unsigned char sha1sum[20];
2591 #endif
2592
2593 mbedtls_mpi K;
2594
2595 mbedtls_mpi_init( &K );
2596 mbedtls_rsa_init( &rsa );
2597
2598 MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( &K, 16, RSA_N ) );
2599 MBEDTLS_MPI_CHK( mbedtls_rsa_import( &rsa, &K, NULL, NULL, NULL, NULL ) );
2600 MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( &K, 16, RSA_P ) );
2601 MBEDTLS_MPI_CHK( mbedtls_rsa_import( &rsa, NULL, &K, NULL, NULL, NULL ) );
2602 MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( &K, 16, RSA_Q ) );
2603 MBEDTLS_MPI_CHK( mbedtls_rsa_import( &rsa, NULL, NULL, &K, NULL, NULL ) );
2604 MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( &K, 16, RSA_D ) );
2605 MBEDTLS_MPI_CHK( mbedtls_rsa_import( &rsa, NULL, NULL, NULL, &K, NULL ) );
2606 MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( &K, 16, RSA_E ) );
2607 MBEDTLS_MPI_CHK( mbedtls_rsa_import( &rsa, NULL, NULL, NULL, NULL, &K ) );
2608
2609 MBEDTLS_MPI_CHK( mbedtls_rsa_complete( &rsa ) );
2610
2611 if( verbose != 0 )
2612 mbedtls_printf( " RSA key validation: " );
2613
2614 if( mbedtls_rsa_check_pubkey( &rsa ) != 0 ||
2615 mbedtls_rsa_check_privkey( &rsa ) != 0 )
2616 {
2617 if( verbose != 0 )
2618 mbedtls_printf( "failed\n" );
2619
2620 ret = 1;
2621 goto cleanup;
2622 }
2623
2624 if( verbose != 0 )
2625 mbedtls_printf( "passed\n PKCS#1 encryption : " );
2626
2627 memcpy( rsa_plaintext, RSA_PT, PT_LEN );
2628
2629 if( mbedtls_rsa_pkcs1_encrypt( &rsa, myrand, NULL,
2630 PT_LEN, rsa_plaintext,
2631 rsa_ciphertext ) != 0 )
2632 {
2633 if( verbose != 0 )
2634 mbedtls_printf( "failed\n" );
2635
2636 ret = 1;
2637 goto cleanup;
2638 }
2639
2640 if( verbose != 0 )
2641 mbedtls_printf( "passed\n PKCS#1 decryption : " );
2642
2643 if( mbedtls_rsa_pkcs1_decrypt( &rsa, myrand, NULL,
2644 &len, rsa_ciphertext, rsa_decrypted,
2645 sizeof(rsa_decrypted) ) != 0 )
2646 {
2647 if( verbose != 0 )
2648 mbedtls_printf( "failed\n" );
2649
2650 ret = 1;
2651 goto cleanup;
2652 }
2653
2654 if( memcmp( rsa_decrypted, rsa_plaintext, len ) != 0 )
2655 {
2656 if( verbose != 0 )
2657 mbedtls_printf( "failed\n" );
2658
2659 ret = 1;
2660 goto cleanup;
2661 }
2662
2663 if( verbose != 0 )
2664 mbedtls_printf( "passed\n" );
2665
2666 #if defined(MBEDTLS_SHA1_C)
2667 if( verbose != 0 )
2668 mbedtls_printf( " PKCS#1 data sign : " );
2669
2670 if( mbedtls_sha1( rsa_plaintext, PT_LEN, sha1sum ) != 0 )
2671 {
2672 if( verbose != 0 )
2673 mbedtls_printf( "failed\n" );
2674
2675 return( 1 );
2676 }
2677
2678 if( mbedtls_rsa_pkcs1_sign( &rsa, myrand, NULL,
2679 MBEDTLS_MD_SHA1, 20,
2680 sha1sum, rsa_ciphertext ) != 0 )
2681 {
2682 if( verbose != 0 )
2683 mbedtls_printf( "failed\n" );
2684
2685 ret = 1;
2686 goto cleanup;
2687 }
2688
2689 if( verbose != 0 )
2690 mbedtls_printf( "passed\n PKCS#1 sig. verify: " );
2691
2692 if( mbedtls_rsa_pkcs1_verify( &rsa, MBEDTLS_MD_SHA1, 20,
2693 sha1sum, rsa_ciphertext ) != 0 )
2694 {
2695 if( verbose != 0 )
2696 mbedtls_printf( "failed\n" );
2697
2698 ret = 1;
2699 goto cleanup;
2700 }
2701
2702 if( verbose != 0 )
2703 mbedtls_printf( "passed\n" );
2704 #endif /* MBEDTLS_SHA1_C */
2705
2706 if( verbose != 0 )
2707 mbedtls_printf( "\n" );
2708
2709 cleanup:
2710 mbedtls_mpi_free( &K );
2711 mbedtls_rsa_free( &rsa );
2712 #else /* MBEDTLS_PKCS1_V15 */
2713 ((void) verbose);
2714 #endif /* MBEDTLS_PKCS1_V15 */
2715 return( ret );
2716 }
2717
2718 #endif /* MBEDTLS_SELF_TEST */
2719
2720 #endif /* MBEDTLS_RSA_C */
2721