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Edison Ai7b079202018-02-28 15:01:47 +08001// SPDX-License-Identifier: Apache-2.0
Jens Wiklander817466c2018-05-22 13:49:31 +02002/*
3 * The RSA public-key cryptosystem
4 *
5 * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
Jens Wiklander817466c2018-05-22 13:49:31 +02006 *
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 */
Jens Wiklander50a57cf2019-03-13 10:41:54 +010021
Jens Wiklander817466c2018-05-22 13:49:31 +020022/*
23 * The following sources were referenced in the design of this implementation
24 * of the RSA algorithm:
25 *
26 * [1] A method for obtaining digital signatures and public-key cryptosystems
27 * R Rivest, A Shamir, and L Adleman
28 * http://people.csail.mit.edu/rivest/pubs.html#RSA78
29 *
30 * [2] Handbook of Applied Cryptography - 1997, Chapter 8
31 * Menezes, van Oorschot and Vanstone
32 *
33 * [3] Malware Guard Extension: Using SGX to Conceal Cache Attacks
34 * Michael Schwarz, Samuel Weiser, Daniel Gruss, Clémentine Maurice and
35 * Stefan Mangard
36 * https://arxiv.org/abs/1702.08719v2
37 *
38 */
39
40#if !defined(MBEDTLS_CONFIG_FILE)
41#include "mbedtls/config.h"
42#else
43#include MBEDTLS_CONFIG_FILE
44#endif
45
46#if defined(MBEDTLS_RSA_C)
47
48#include "mbedtls/rsa.h"
Jens Wiklander50a57cf2019-03-13 10:41:54 +010049#include "mbedtls/rsa_internal.h"
Jens Wiklander817466c2018-05-22 13:49:31 +020050#include "mbedtls/oid.h"
Jens Wiklander50a57cf2019-03-13 10:41:54 +010051#include "mbedtls/platform_util.h"
Jens Wiklander817466c2018-05-22 13:49:31 +020052
53#include <string.h>
54
55#if defined(MBEDTLS_PKCS1_V21)
56#include "mbedtls/md.h"
57#endif
58
59#if defined(MBEDTLS_PKCS1_V15) && !defined(__OpenBSD__)
60#include <stdlib.h>
61#endif
62
63#if defined(MBEDTLS_PLATFORM_C)
64#include "mbedtls/platform.h"
65#else
66#include <stdio.h>
67#define mbedtls_printf printf
68#define mbedtls_calloc calloc
69#define mbedtls_free free
70#endif
71
Jens Wiklander50a57cf2019-03-13 10:41:54 +010072#if !defined(MBEDTLS_RSA_ALT)
73
74/* Parameter validation macros */
75#define RSA_VALIDATE_RET( cond ) \
76 MBEDTLS_INTERNAL_VALIDATE_RET( cond, MBEDTLS_ERR_RSA_BAD_INPUT_DATA )
77#define RSA_VALIDATE( cond ) \
78 MBEDTLS_INTERNAL_VALIDATE( cond )
79
80#if defined(MBEDTLS_PKCS1_V15)
81/* constant-time buffer comparison */
82static inline int mbedtls_safer_memcmp( const void *a, const void *b, size_t n )
83{
84 size_t i;
85 const unsigned char *A = (const unsigned char *) a;
86 const unsigned char *B = (const unsigned char *) b;
87 unsigned char diff = 0;
88
89 for( i = 0; i < n; i++ )
90 diff |= A[i] ^ B[i];
91
92 return( diff );
93}
94#endif /* MBEDTLS_PKCS1_V15 */
95
96int mbedtls_rsa_import( mbedtls_rsa_context *ctx,
97 const mbedtls_mpi *N,
98 const mbedtls_mpi *P, const mbedtls_mpi *Q,
99 const mbedtls_mpi *D, const mbedtls_mpi *E )
100{
101 int ret;
102 RSA_VALIDATE_RET( ctx != NULL );
103
104 if( ( N != NULL && ( ret = mbedtls_mpi_copy( &ctx->N, N ) ) != 0 ) ||
105 ( P != NULL && ( ret = mbedtls_mpi_copy( &ctx->P, P ) ) != 0 ) ||
106 ( Q != NULL && ( ret = mbedtls_mpi_copy( &ctx->Q, Q ) ) != 0 ) ||
107 ( D != NULL && ( ret = mbedtls_mpi_copy( &ctx->D, D ) ) != 0 ) ||
108 ( E != NULL && ( ret = mbedtls_mpi_copy( &ctx->E, E ) ) != 0 ) )
109 {
110 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA + ret );
111 }
112
113 if( N != NULL )
114 ctx->len = mbedtls_mpi_size( &ctx->N );
115
116 return( 0 );
117}
118
119int mbedtls_rsa_import_raw( mbedtls_rsa_context *ctx,
120 unsigned char const *N, size_t N_len,
121 unsigned char const *P, size_t P_len,
122 unsigned char const *Q, size_t Q_len,
123 unsigned char const *D, size_t D_len,
124 unsigned char const *E, size_t E_len )
125{
126 int ret = 0;
127 RSA_VALIDATE_RET( ctx != NULL );
128
129 if( N != NULL )
130 {
131 MBEDTLS_MPI_CHK( mbedtls_mpi_read_binary( &ctx->N, N, N_len ) );
132 ctx->len = mbedtls_mpi_size( &ctx->N );
133 }
134
135 if( P != NULL )
136 MBEDTLS_MPI_CHK( mbedtls_mpi_read_binary( &ctx->P, P, P_len ) );
137
138 if( Q != NULL )
139 MBEDTLS_MPI_CHK( mbedtls_mpi_read_binary( &ctx->Q, Q, Q_len ) );
140
141 if( D != NULL )
142 MBEDTLS_MPI_CHK( mbedtls_mpi_read_binary( &ctx->D, D, D_len ) );
143
144 if( E != NULL )
145 MBEDTLS_MPI_CHK( mbedtls_mpi_read_binary( &ctx->E, E, E_len ) );
146
147cleanup:
148
149 if( ret != 0 )
150 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA + ret );
151
152 return( 0 );
153}
154
155/*
156 * Checks whether the context fields are set in such a way
157 * that the RSA primitives will be able to execute without error.
158 * It does *not* make guarantees for consistency of the parameters.
159 */
160static int rsa_check_context( mbedtls_rsa_context const *ctx, int is_priv,
161 int blinding_needed )
162{
163#if !defined(MBEDTLS_RSA_NO_CRT)
164 /* blinding_needed is only used for NO_CRT to decide whether
165 * P,Q need to be present or not. */
166 ((void) blinding_needed);
167#endif
168
169 if( ctx->len != mbedtls_mpi_size( &ctx->N ) ||
170 ctx->len > MBEDTLS_MPI_MAX_SIZE )
171 {
172 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
173 }
174
175 /*
176 * 1. Modular exponentiation needs positive, odd moduli.
177 */
178
179 /* Modular exponentiation wrt. N is always used for
180 * RSA public key operations. */
181 if( mbedtls_mpi_cmp_int( &ctx->N, 0 ) <= 0 ||
182 mbedtls_mpi_get_bit( &ctx->N, 0 ) == 0 )
183 {
184 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
185 }
186
187#if !defined(MBEDTLS_RSA_NO_CRT)
188 /* Modular exponentiation for P and Q is only
189 * used for private key operations and if CRT
190 * is used. */
191 if( is_priv &&
192 ( mbedtls_mpi_cmp_int( &ctx->P, 0 ) <= 0 ||
193 mbedtls_mpi_get_bit( &ctx->P, 0 ) == 0 ||
194 mbedtls_mpi_cmp_int( &ctx->Q, 0 ) <= 0 ||
195 mbedtls_mpi_get_bit( &ctx->Q, 0 ) == 0 ) )
196 {
197 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
198 }
199#endif /* !MBEDTLS_RSA_NO_CRT */
200
201 /*
202 * 2. Exponents must be positive
203 */
204
205 /* Always need E for public key operations */
206 if( mbedtls_mpi_cmp_int( &ctx->E, 0 ) <= 0 )
207 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
208
209#if defined(MBEDTLS_RSA_NO_CRT)
210 /* For private key operations, use D or DP & DQ
211 * as (unblinded) exponents. */
212 if( is_priv && mbedtls_mpi_cmp_int( &ctx->D, 0 ) <= 0 )
213 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
214#else
215 if( is_priv &&
216 ( mbedtls_mpi_cmp_int( &ctx->DP, 0 ) <= 0 ||
217 mbedtls_mpi_cmp_int( &ctx->DQ, 0 ) <= 0 ) )
218 {
219 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
220 }
221#endif /* MBEDTLS_RSA_NO_CRT */
222
223 /* Blinding shouldn't make exponents negative either,
224 * so check that P, Q >= 1 if that hasn't yet been
225 * done as part of 1. */
226#if defined(MBEDTLS_RSA_NO_CRT)
227 if( is_priv && blinding_needed &&
228 ( mbedtls_mpi_cmp_int( &ctx->P, 0 ) <= 0 ||
229 mbedtls_mpi_cmp_int( &ctx->Q, 0 ) <= 0 ) )
230 {
231 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
232 }
233#endif
234
235 /* It wouldn't lead to an error if it wasn't satisfied,
236 * but check for QP >= 1 nonetheless. */
237#if !defined(MBEDTLS_RSA_NO_CRT)
238 if( is_priv &&
239 mbedtls_mpi_cmp_int( &ctx->QP, 0 ) <= 0 )
240 {
241 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
242 }
243#endif
244
245 return( 0 );
246}
247
248int mbedtls_rsa_complete( mbedtls_rsa_context *ctx )
249{
250 int ret = 0;
251 int have_N, have_P, have_Q, have_D, have_E;
252 int n_missing, pq_missing, d_missing, is_pub, is_priv;
253
254 RSA_VALIDATE_RET( ctx != NULL );
255
256 have_N = ( mbedtls_mpi_cmp_int( &ctx->N, 0 ) != 0 );
257 have_P = ( mbedtls_mpi_cmp_int( &ctx->P, 0 ) != 0 );
258 have_Q = ( mbedtls_mpi_cmp_int( &ctx->Q, 0 ) != 0 );
259 have_D = ( mbedtls_mpi_cmp_int( &ctx->D, 0 ) != 0 );
260 have_E = ( mbedtls_mpi_cmp_int( &ctx->E, 0 ) != 0 );
261
262 /*
263 * Check whether provided parameters are enough
264 * to deduce all others. The following incomplete
265 * parameter sets for private keys are supported:
266 *
267 * (1) P, Q missing.
268 * (2) D and potentially N missing.
269 *
270 */
271
272 n_missing = have_P && have_Q && have_D && have_E;
273 pq_missing = have_N && !have_P && !have_Q && have_D && have_E;
274 d_missing = have_P && have_Q && !have_D && have_E;
275 is_pub = have_N && !have_P && !have_Q && !have_D && have_E;
276
277 /* These three alternatives are mutually exclusive */
278 is_priv = n_missing || pq_missing || d_missing;
279
280 if( !is_priv && !is_pub )
281 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
282
283 /*
284 * Step 1: Deduce N if P, Q are provided.
285 */
286
287 if( !have_N && have_P && have_Q )
288 {
289 if( ( ret = mbedtls_mpi_mul_mpi( &ctx->N, &ctx->P,
290 &ctx->Q ) ) != 0 )
291 {
292 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA + ret );
293 }
294
295 ctx->len = mbedtls_mpi_size( &ctx->N );
296 }
297
298 /*
299 * Step 2: Deduce and verify all remaining core parameters.
300 */
301
302 if( pq_missing )
303 {
304 ret = mbedtls_rsa_deduce_primes( &ctx->N, &ctx->E, &ctx->D,
305 &ctx->P, &ctx->Q );
306 if( ret != 0 )
307 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA + ret );
308
309 }
310 else if( d_missing )
311 {
312 if( ( ret = mbedtls_rsa_deduce_private_exponent( &ctx->P,
313 &ctx->Q,
314 &ctx->E,
315 &ctx->D ) ) != 0 )
316 {
317 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA + ret );
318 }
319 }
320
321 /*
322 * Step 3: Deduce all additional parameters specific
323 * to our current RSA implementation.
324 */
325
326#if !defined(MBEDTLS_RSA_NO_CRT)
327 if( is_priv )
328 {
329 ret = mbedtls_rsa_deduce_crt( &ctx->P, &ctx->Q, &ctx->D,
330 &ctx->DP, &ctx->DQ, &ctx->QP );
331 if( ret != 0 )
332 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA + ret );
333 }
334#endif /* MBEDTLS_RSA_NO_CRT */
335
336 /*
337 * Step 3: Basic sanity checks
338 */
339
340 return( rsa_check_context( ctx, is_priv, 1 ) );
341}
342
343int mbedtls_rsa_export_raw( const mbedtls_rsa_context *ctx,
344 unsigned char *N, size_t N_len,
345 unsigned char *P, size_t P_len,
346 unsigned char *Q, size_t Q_len,
347 unsigned char *D, size_t D_len,
348 unsigned char *E, size_t E_len )
349{
350 int ret = 0;
351 int is_priv;
352 RSA_VALIDATE_RET( ctx != NULL );
353
354 /* Check if key is private or public */
355 is_priv =
356 mbedtls_mpi_cmp_int( &ctx->N, 0 ) != 0 &&
357 mbedtls_mpi_cmp_int( &ctx->P, 0 ) != 0 &&
358 mbedtls_mpi_cmp_int( &ctx->Q, 0 ) != 0 &&
359 mbedtls_mpi_cmp_int( &ctx->D, 0 ) != 0 &&
360 mbedtls_mpi_cmp_int( &ctx->E, 0 ) != 0;
361
362 if( !is_priv )
363 {
364 /* If we're trying to export private parameters for a public key,
365 * something must be wrong. */
366 if( P != NULL || Q != NULL || D != NULL )
367 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
368
369 }
370
371 if( N != NULL )
372 MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &ctx->N, N, N_len ) );
373
374 if( P != NULL )
375 MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &ctx->P, P, P_len ) );
376
377 if( Q != NULL )
378 MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &ctx->Q, Q, Q_len ) );
379
380 if( D != NULL )
381 MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &ctx->D, D, D_len ) );
382
383 if( E != NULL )
384 MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &ctx->E, E, E_len ) );
385
386cleanup:
387
388 return( ret );
389}
390
391int mbedtls_rsa_export( const mbedtls_rsa_context *ctx,
392 mbedtls_mpi *N, mbedtls_mpi *P, mbedtls_mpi *Q,
393 mbedtls_mpi *D, mbedtls_mpi *E )
394{
395 int ret;
396 int is_priv;
397 RSA_VALIDATE_RET( ctx != NULL );
398
399 /* Check if key is private or public */
400 is_priv =
401 mbedtls_mpi_cmp_int( &ctx->N, 0 ) != 0 &&
402 mbedtls_mpi_cmp_int( &ctx->P, 0 ) != 0 &&
403 mbedtls_mpi_cmp_int( &ctx->Q, 0 ) != 0 &&
404 mbedtls_mpi_cmp_int( &ctx->D, 0 ) != 0 &&
405 mbedtls_mpi_cmp_int( &ctx->E, 0 ) != 0;
406
407 if( !is_priv )
408 {
409 /* If we're trying to export private parameters for a public key,
410 * something must be wrong. */
411 if( P != NULL || Q != NULL || D != NULL )
412 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
413
414 }
415
416 /* Export all requested core parameters. */
417
418 if( ( N != NULL && ( ret = mbedtls_mpi_copy( N, &ctx->N ) ) != 0 ) ||
419 ( P != NULL && ( ret = mbedtls_mpi_copy( P, &ctx->P ) ) != 0 ) ||
420 ( Q != NULL && ( ret = mbedtls_mpi_copy( Q, &ctx->Q ) ) != 0 ) ||
421 ( D != NULL && ( ret = mbedtls_mpi_copy( D, &ctx->D ) ) != 0 ) ||
422 ( E != NULL && ( ret = mbedtls_mpi_copy( E, &ctx->E ) ) != 0 ) )
423 {
424 return( ret );
425 }
426
427 return( 0 );
428}
429
430/*
431 * Export CRT parameters
432 * This must also be implemented if CRT is not used, for being able to
433 * write DER encoded RSA keys. The helper function mbedtls_rsa_deduce_crt
434 * can be used in this case.
435 */
436int mbedtls_rsa_export_crt( const mbedtls_rsa_context *ctx,
437 mbedtls_mpi *DP, mbedtls_mpi *DQ, mbedtls_mpi *QP )
438{
439 int ret;
440 int is_priv;
441 RSA_VALIDATE_RET( ctx != NULL );
442
443 /* Check if key is private or public */
444 is_priv =
445 mbedtls_mpi_cmp_int( &ctx->N, 0 ) != 0 &&
446 mbedtls_mpi_cmp_int( &ctx->P, 0 ) != 0 &&
447 mbedtls_mpi_cmp_int( &ctx->Q, 0 ) != 0 &&
448 mbedtls_mpi_cmp_int( &ctx->D, 0 ) != 0 &&
449 mbedtls_mpi_cmp_int( &ctx->E, 0 ) != 0;
450
451 if( !is_priv )
452 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
453
454#if !defined(MBEDTLS_RSA_NO_CRT)
455 /* Export all requested blinding parameters. */
456 if( ( DP != NULL && ( ret = mbedtls_mpi_copy( DP, &ctx->DP ) ) != 0 ) ||
457 ( DQ != NULL && ( ret = mbedtls_mpi_copy( DQ, &ctx->DQ ) ) != 0 ) ||
458 ( QP != NULL && ( ret = mbedtls_mpi_copy( QP, &ctx->QP ) ) != 0 ) )
459 {
460 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA + ret );
461 }
462#else
463 if( ( ret = mbedtls_rsa_deduce_crt( &ctx->P, &ctx->Q, &ctx->D,
464 DP, DQ, QP ) ) != 0 )
465 {
466 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA + ret );
467 }
468#endif
469
470 return( 0 );
Jens Wiklander817466c2018-05-22 13:49:31 +0200471}
472
473/*
474 * Initialize an RSA context
475 */
476void mbedtls_rsa_init( mbedtls_rsa_context *ctx,
477 int padding,
478 int hash_id )
479{
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100480 RSA_VALIDATE( ctx != NULL );
481 RSA_VALIDATE( padding == MBEDTLS_RSA_PKCS_V15 ||
482 padding == MBEDTLS_RSA_PKCS_V21 );
483
Jens Wiklander817466c2018-05-22 13:49:31 +0200484 memset( ctx, 0, sizeof( mbedtls_rsa_context ) );
485
486 mbedtls_rsa_set_padding( ctx, padding, hash_id );
487
488#if defined(MBEDTLS_THREADING_C)
489 mbedtls_mutex_init( &ctx->mutex );
490#endif
491}
492
493/*
494 * Set padding for an existing RSA context
495 */
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100496void mbedtls_rsa_set_padding( mbedtls_rsa_context *ctx, int padding,
497 int hash_id )
Jens Wiklander817466c2018-05-22 13:49:31 +0200498{
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100499 RSA_VALIDATE( ctx != NULL );
500 RSA_VALIDATE( padding == MBEDTLS_RSA_PKCS_V15 ||
501 padding == MBEDTLS_RSA_PKCS_V21 );
502
Jens Wiklander817466c2018-05-22 13:49:31 +0200503 ctx->padding = padding;
504 ctx->hash_id = hash_id;
505}
506
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100507/*
508 * Get length in bytes of RSA modulus
509 */
510
511size_t mbedtls_rsa_get_len( const mbedtls_rsa_context *ctx )
512{
513 return( ctx->len );
514}
515
516
Jens Wiklander817466c2018-05-22 13:49:31 +0200517#if defined(MBEDTLS_GENPRIME)
518
519/*
520 * Generate an RSA keypair
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100521 *
522 * This generation method follows the RSA key pair generation procedure of
523 * FIPS 186-4 if 2^16 < exponent < 2^256 and nbits = 2048 or nbits = 3072.
Jens Wiklander817466c2018-05-22 13:49:31 +0200524 */
525int mbedtls_rsa_gen_key( mbedtls_rsa_context *ctx,
526 int (*f_rng)(void *, unsigned char *, size_t),
527 void *p_rng,
528 unsigned int nbits, int exponent )
529{
530 int ret;
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100531 mbedtls_mpi H, G, L;
532 int prime_quality = 0;
533 RSA_VALIDATE_RET( ctx != NULL );
534 RSA_VALIDATE_RET( f_rng != NULL );
Jens Wiklander817466c2018-05-22 13:49:31 +0200535
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100536 if( nbits < 128 || exponent < 3 || nbits % 2 != 0 )
Jens Wiklander817466c2018-05-22 13:49:31 +0200537 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
538
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100539 /*
540 * If the modulus is 1024 bit long or shorter, then the security strength of
541 * the RSA algorithm is less than or equal to 80 bits and therefore an error
542 * rate of 2^-80 is sufficient.
543 */
544 if( nbits > 1024 )
545 prime_quality = MBEDTLS_MPI_GEN_PRIME_FLAG_LOW_ERR;
Jens Wiklander817466c2018-05-22 13:49:31 +0200546
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100547 mbedtls_mpi_init( &H );
548 mbedtls_mpi_init( &G );
549 mbedtls_mpi_init( &L );
Jens Wiklander817466c2018-05-22 13:49:31 +0200550
551 /*
552 * find primes P and Q with Q < P so that:
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100553 * 1. |P-Q| > 2^( nbits / 2 - 100 )
554 * 2. GCD( E, (P-1)*(Q-1) ) == 1
555 * 3. E^-1 mod LCM(P-1, Q-1) > 2^( nbits / 2 )
Jens Wiklander817466c2018-05-22 13:49:31 +0200556 */
557 MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &ctx->E, exponent ) );
558
559 do
560 {
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100561 MBEDTLS_MPI_CHK( mbedtls_mpi_gen_prime( &ctx->P, nbits >> 1,
562 prime_quality, f_rng, p_rng ) );
Jens Wiklander817466c2018-05-22 13:49:31 +0200563
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100564 MBEDTLS_MPI_CHK( mbedtls_mpi_gen_prime( &ctx->Q, nbits >> 1,
565 prime_quality, f_rng, p_rng ) );
Jens Wiklander817466c2018-05-22 13:49:31 +0200566
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100567 /* make sure the difference between p and q is not too small (FIPS 186-4 §B.3.3 step 5.4) */
568 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &H, &ctx->P, &ctx->Q ) );
569 if( mbedtls_mpi_bitlen( &H ) <= ( ( nbits >= 200 ) ? ( ( nbits >> 1 ) - 99 ) : 0 ) )
Jens Wiklander817466c2018-05-22 13:49:31 +0200570 continue;
571
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100572 /* not required by any standards, but some users rely on the fact that P > Q */
573 if( H.s < 0 )
574 mbedtls_mpi_swap( &ctx->P, &ctx->Q );
Jens Wiklander817466c2018-05-22 13:49:31 +0200575
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100576 /* Temporarily replace P,Q by P-1, Q-1 */
577 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &ctx->P, &ctx->P, 1 ) );
578 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &ctx->Q, &ctx->Q, 1 ) );
579 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &H, &ctx->P, &ctx->Q ) );
Jens Wiklander817466c2018-05-22 13:49:31 +0200580
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100581 /* check GCD( E, (P-1)*(Q-1) ) == 1 (FIPS 186-4 §B.3.1 criterion 2(a)) */
Jens Wiklander817466c2018-05-22 13:49:31 +0200582 MBEDTLS_MPI_CHK( mbedtls_mpi_gcd( &G, &ctx->E, &H ) );
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100583 if( mbedtls_mpi_cmp_int( &G, 1 ) != 0 )
584 continue;
Jens Wiklander817466c2018-05-22 13:49:31 +0200585
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100586 /* compute smallest possible D = E^-1 mod LCM(P-1, Q-1) (FIPS 186-4 §B.3.1 criterion 3(b)) */
587 MBEDTLS_MPI_CHK( mbedtls_mpi_gcd( &G, &ctx->P, &ctx->Q ) );
588 MBEDTLS_MPI_CHK( mbedtls_mpi_div_mpi( &L, NULL, &H, &G ) );
589 MBEDTLS_MPI_CHK( mbedtls_mpi_inv_mod( &ctx->D, &ctx->E, &L ) );
590
591 if( mbedtls_mpi_bitlen( &ctx->D ) <= ( ( nbits + 1 ) / 2 ) ) // (FIPS 186-4 §B.3.1 criterion 3(a))
592 continue;
593
594 break;
595 }
596 while( 1 );
597
598 /* Restore P,Q */
599 MBEDTLS_MPI_CHK( mbedtls_mpi_add_int( &ctx->P, &ctx->P, 1 ) );
600 MBEDTLS_MPI_CHK( mbedtls_mpi_add_int( &ctx->Q, &ctx->Q, 1 ) );
601
602 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &ctx->N, &ctx->P, &ctx->Q ) );
603
604 ctx->len = mbedtls_mpi_size( &ctx->N );
605
606#if !defined(MBEDTLS_RSA_NO_CRT)
Jens Wiklander817466c2018-05-22 13:49:31 +0200607 /*
Jens Wiklander817466c2018-05-22 13:49:31 +0200608 * DP = D mod (P - 1)
609 * DQ = D mod (Q - 1)
610 * QP = Q^-1 mod P
611 */
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100612 MBEDTLS_MPI_CHK( mbedtls_rsa_deduce_crt( &ctx->P, &ctx->Q, &ctx->D,
613 &ctx->DP, &ctx->DQ, &ctx->QP ) );
614#endif /* MBEDTLS_RSA_NO_CRT */
Jens Wiklander817466c2018-05-22 13:49:31 +0200615
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100616 /* Double-check */
617 MBEDTLS_MPI_CHK( mbedtls_rsa_check_privkey( ctx ) );
Jens Wiklander817466c2018-05-22 13:49:31 +0200618
619cleanup:
620
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100621 mbedtls_mpi_free( &H );
622 mbedtls_mpi_free( &G );
623 mbedtls_mpi_free( &L );
Jens Wiklander817466c2018-05-22 13:49:31 +0200624
625 if( ret != 0 )
626 {
627 mbedtls_rsa_free( ctx );
628 return( MBEDTLS_ERR_RSA_KEY_GEN_FAILED + ret );
629 }
630
631 return( 0 );
632}
633
634#endif /* MBEDTLS_GENPRIME */
635
636/*
637 * Check a public RSA key
638 */
639int mbedtls_rsa_check_pubkey( const mbedtls_rsa_context *ctx )
640{
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100641 RSA_VALIDATE_RET( ctx != NULL );
642
643 if( rsa_check_context( ctx, 0 /* public */, 0 /* no blinding */ ) != 0 )
Jens Wiklander817466c2018-05-22 13:49:31 +0200644 return( MBEDTLS_ERR_RSA_KEY_CHECK_FAILED );
645
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100646 if( mbedtls_mpi_bitlen( &ctx->N ) < 128 )
647 {
Jens Wiklander817466c2018-05-22 13:49:31 +0200648 return( MBEDTLS_ERR_RSA_KEY_CHECK_FAILED );
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100649 }
Jens Wiklander817466c2018-05-22 13:49:31 +0200650
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100651 if( mbedtls_mpi_get_bit( &ctx->E, 0 ) == 0 ||
652 mbedtls_mpi_bitlen( &ctx->E ) < 2 ||
Jens Wiklander817466c2018-05-22 13:49:31 +0200653 mbedtls_mpi_cmp_mpi( &ctx->E, &ctx->N ) >= 0 )
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100654 {
Jens Wiklander817466c2018-05-22 13:49:31 +0200655 return( MBEDTLS_ERR_RSA_KEY_CHECK_FAILED );
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100656 }
Jens Wiklander817466c2018-05-22 13:49:31 +0200657
658 return( 0 );
659}
660
661/*
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100662 * Check for the consistency of all fields in an RSA private key context
Jens Wiklander817466c2018-05-22 13:49:31 +0200663 */
664int mbedtls_rsa_check_privkey( const mbedtls_rsa_context *ctx )
665{
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100666 RSA_VALIDATE_RET( ctx != NULL );
Jens Wiklander817466c2018-05-22 13:49:31 +0200667
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100668 if( mbedtls_rsa_check_pubkey( ctx ) != 0 ||
669 rsa_check_context( ctx, 1 /* private */, 1 /* blinding */ ) != 0 )
Jens Wiklander817466c2018-05-22 13:49:31 +0200670 {
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100671 return( MBEDTLS_ERR_RSA_KEY_CHECK_FAILED );
Jens Wiklander817466c2018-05-22 13:49:31 +0200672 }
673
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100674 if( mbedtls_rsa_validate_params( &ctx->N, &ctx->P, &ctx->Q,
675 &ctx->D, &ctx->E, NULL, NULL ) != 0 )
676 {
677 return( MBEDTLS_ERR_RSA_KEY_CHECK_FAILED );
678 }
Jens Wiklander817466c2018-05-22 13:49:31 +0200679
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100680#if !defined(MBEDTLS_RSA_NO_CRT)
681 else if( mbedtls_rsa_validate_crt( &ctx->P, &ctx->Q, &ctx->D,
682 &ctx->DP, &ctx->DQ, &ctx->QP ) != 0 )
683 {
684 return( MBEDTLS_ERR_RSA_KEY_CHECK_FAILED );
685 }
686#endif
Jens Wiklander817466c2018-05-22 13:49:31 +0200687
688 return( 0 );
689}
690
691/*
692 * Check if contexts holding a public and private key match
693 */
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100694int mbedtls_rsa_check_pub_priv( const mbedtls_rsa_context *pub,
695 const mbedtls_rsa_context *prv )
Jens Wiklander817466c2018-05-22 13:49:31 +0200696{
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100697 RSA_VALIDATE_RET( pub != NULL );
698 RSA_VALIDATE_RET( prv != NULL );
699
700 if( mbedtls_rsa_check_pubkey( pub ) != 0 ||
Jens Wiklander817466c2018-05-22 13:49:31 +0200701 mbedtls_rsa_check_privkey( prv ) != 0 )
702 {
703 return( MBEDTLS_ERR_RSA_KEY_CHECK_FAILED );
704 }
705
706 if( mbedtls_mpi_cmp_mpi( &pub->N, &prv->N ) != 0 ||
707 mbedtls_mpi_cmp_mpi( &pub->E, &prv->E ) != 0 )
708 {
709 return( MBEDTLS_ERR_RSA_KEY_CHECK_FAILED );
710 }
711
712 return( 0 );
713}
714
715/*
716 * Do an RSA public key operation
717 */
718int mbedtls_rsa_public( mbedtls_rsa_context *ctx,
719 const unsigned char *input,
720 unsigned char *output )
721{
722 int ret;
723 size_t olen;
724 mbedtls_mpi T;
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100725 RSA_VALIDATE_RET( ctx != NULL );
726 RSA_VALIDATE_RET( input != NULL );
727 RSA_VALIDATE_RET( output != NULL );
728
729 if( rsa_check_context( ctx, 0 /* public */, 0 /* no blinding */ ) )
730 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
Jens Wiklander817466c2018-05-22 13:49:31 +0200731
732 mbedtls_mpi_init( &T );
733
734#if defined(MBEDTLS_THREADING_C)
735 if( ( ret = mbedtls_mutex_lock( &ctx->mutex ) ) != 0 )
736 return( ret );
737#endif
738
739 MBEDTLS_MPI_CHK( mbedtls_mpi_read_binary( &T, input, ctx->len ) );
740
741 if( mbedtls_mpi_cmp_mpi( &T, &ctx->N ) >= 0 )
742 {
743 ret = MBEDTLS_ERR_MPI_BAD_INPUT_DATA;
744 goto cleanup;
745 }
746
747 olen = ctx->len;
748 MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &T, &T, &ctx->E, &ctx->N, &ctx->RN ) );
749 MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &T, output, olen ) );
750
751cleanup:
752#if defined(MBEDTLS_THREADING_C)
753 if( mbedtls_mutex_unlock( &ctx->mutex ) != 0 )
754 return( MBEDTLS_ERR_THREADING_MUTEX_ERROR );
755#endif
756
757 mbedtls_mpi_free( &T );
758
759 if( ret != 0 )
760 return( MBEDTLS_ERR_RSA_PUBLIC_FAILED + ret );
761
762 return( 0 );
763}
764
765/*
766 * Generate or update blinding values, see section 10 of:
767 * KOCHER, Paul C. Timing attacks on implementations of Diffie-Hellman, RSA,
768 * DSS, and other systems. In : Advances in Cryptology-CRYPTO'96. Springer
769 * Berlin Heidelberg, 1996. p. 104-113.
770 */
771static int rsa_prepare_blinding( mbedtls_rsa_context *ctx,
772 int (*f_rng)(void *, unsigned char *, size_t), void *p_rng )
773{
774 int ret, count = 0;
775
776 if( ctx->Vf.p != NULL )
777 {
778 /* We already have blinding values, just update them by squaring */
779 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &ctx->Vi, &ctx->Vi, &ctx->Vi ) );
780 MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &ctx->Vi, &ctx->Vi, &ctx->N ) );
781 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &ctx->Vf, &ctx->Vf, &ctx->Vf ) );
782 MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &ctx->Vf, &ctx->Vf, &ctx->N ) );
783
784 goto cleanup;
785 }
786
787 /* Unblinding value: Vf = random number, invertible mod N */
788 do {
789 if( count++ > 10 )
790 return( MBEDTLS_ERR_RSA_RNG_FAILED );
791
792 MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( &ctx->Vf, ctx->len - 1, f_rng, p_rng ) );
793 MBEDTLS_MPI_CHK( mbedtls_mpi_gcd( &ctx->Vi, &ctx->Vf, &ctx->N ) );
794 } while( mbedtls_mpi_cmp_int( &ctx->Vi, 1 ) != 0 );
795
796 /* Blinding value: Vi = Vf^(-e) mod N */
797 MBEDTLS_MPI_CHK( mbedtls_mpi_inv_mod( &ctx->Vi, &ctx->Vf, &ctx->N ) );
798 MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &ctx->Vi, &ctx->Vi, &ctx->E, &ctx->N, &ctx->RN ) );
799
800
801cleanup:
802 return( ret );
803}
804
805/*
806 * Exponent blinding supposed to prevent side-channel attacks using multiple
807 * traces of measurements to recover the RSA key. The more collisions are there,
808 * the more bits of the key can be recovered. See [3].
809 *
810 * Collecting n collisions with m bit long blinding value requires 2^(m-m/n)
811 * observations on avarage.
812 *
813 * For example with 28 byte blinding to achieve 2 collisions the adversary has
814 * to make 2^112 observations on avarage.
815 *
816 * (With the currently (as of 2017 April) known best algorithms breaking 2048
817 * bit RSA requires approximately as much time as trying out 2^112 random keys.
818 * Thus in this sense with 28 byte blinding the security is not reduced by
819 * side-channel attacks like the one in [3])
820 *
821 * This countermeasure does not help if the key recovery is possible with a
822 * single trace.
823 */
824#define RSA_EXPONENT_BLINDING 28
825
826/*
827 * Do an RSA private key operation
828 */
829int mbedtls_rsa_private( mbedtls_rsa_context *ctx,
830 int (*f_rng)(void *, unsigned char *, size_t),
831 void *p_rng,
832 const unsigned char *input,
833 unsigned char *output )
834{
835 int ret;
836 size_t olen;
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100837
838 /* Temporary holding the result */
839 mbedtls_mpi T;
840
841 /* Temporaries holding P-1, Q-1 and the
842 * exponent blinding factor, respectively. */
Jens Wiklander817466c2018-05-22 13:49:31 +0200843 mbedtls_mpi P1, Q1, R;
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100844
845#if !defined(MBEDTLS_RSA_NO_CRT)
846 /* Temporaries holding the results mod p resp. mod q. */
847 mbedtls_mpi TP, TQ;
848
849 /* Temporaries holding the blinded exponents for
850 * the mod p resp. mod q computation (if used). */
Jens Wiklander817466c2018-05-22 13:49:31 +0200851 mbedtls_mpi DP_blind, DQ_blind;
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100852
853 /* Pointers to actual exponents to be used - either the unblinded
854 * or the blinded ones, depending on the presence of a PRNG. */
Jens Wiklander817466c2018-05-22 13:49:31 +0200855 mbedtls_mpi *DP = &ctx->DP;
856 mbedtls_mpi *DQ = &ctx->DQ;
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100857#else
858 /* Temporary holding the blinded exponent (if used). */
859 mbedtls_mpi D_blind;
860
861 /* Pointer to actual exponent to be used - either the unblinded
862 * or the blinded one, depending on the presence of a PRNG. */
863 mbedtls_mpi *D = &ctx->D;
864#endif /* MBEDTLS_RSA_NO_CRT */
865
866 /* Temporaries holding the initial input and the double
867 * checked result; should be the same in the end. */
868 mbedtls_mpi I, C;
869
870 RSA_VALIDATE_RET( ctx != NULL );
871 RSA_VALIDATE_RET( input != NULL );
872 RSA_VALIDATE_RET( output != NULL );
873
874 if( rsa_check_context( ctx, 1 /* private key checks */,
875 f_rng != NULL /* blinding y/n */ ) != 0 )
876 {
877 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
878 }
879
880#if defined(MBEDTLS_THREADING_C)
881 if( ( ret = mbedtls_mutex_lock( &ctx->mutex ) ) != 0 )
882 return( ret );
Jens Wiklander817466c2018-05-22 13:49:31 +0200883#endif
884
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100885 /* MPI Initialization */
886 mbedtls_mpi_init( &T );
Jens Wiklander817466c2018-05-22 13:49:31 +0200887
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100888 mbedtls_mpi_init( &P1 );
889 mbedtls_mpi_init( &Q1 );
890 mbedtls_mpi_init( &R );
Jens Wiklander817466c2018-05-22 13:49:31 +0200891
892 if( f_rng != NULL )
893 {
894#if defined(MBEDTLS_RSA_NO_CRT)
895 mbedtls_mpi_init( &D_blind );
896#else
897 mbedtls_mpi_init( &DP_blind );
898 mbedtls_mpi_init( &DQ_blind );
899#endif
900 }
901
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100902#if !defined(MBEDTLS_RSA_NO_CRT)
903 mbedtls_mpi_init( &TP ); mbedtls_mpi_init( &TQ );
Jens Wiklander817466c2018-05-22 13:49:31 +0200904#endif
905
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100906 mbedtls_mpi_init( &I );
907 mbedtls_mpi_init( &C );
908
909 /* End of MPI initialization */
910
Jens Wiklander817466c2018-05-22 13:49:31 +0200911 MBEDTLS_MPI_CHK( mbedtls_mpi_read_binary( &T, input, ctx->len ) );
912 if( mbedtls_mpi_cmp_mpi( &T, &ctx->N ) >= 0 )
913 {
914 ret = MBEDTLS_ERR_MPI_BAD_INPUT_DATA;
915 goto cleanup;
916 }
917
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100918 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &I, &T ) );
919
Jens Wiklander817466c2018-05-22 13:49:31 +0200920 if( f_rng != NULL )
921 {
922 /*
923 * Blinding
924 * T = T * Vi mod N
925 */
926 MBEDTLS_MPI_CHK( rsa_prepare_blinding( ctx, f_rng, p_rng ) );
927 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &T, &T, &ctx->Vi ) );
928 MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &T, &T, &ctx->N ) );
929
930 /*
931 * Exponent blinding
932 */
933 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &P1, &ctx->P, 1 ) );
934 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &Q1, &ctx->Q, 1 ) );
935
936#if defined(MBEDTLS_RSA_NO_CRT)
937 /*
938 * D_blind = ( P - 1 ) * ( Q - 1 ) * R + D
939 */
940 MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( &R, RSA_EXPONENT_BLINDING,
941 f_rng, p_rng ) );
942 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &D_blind, &P1, &Q1 ) );
943 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &D_blind, &D_blind, &R ) );
944 MBEDTLS_MPI_CHK( mbedtls_mpi_add_mpi( &D_blind, &D_blind, &ctx->D ) );
945
946 D = &D_blind;
947#else
948 /*
949 * DP_blind = ( P - 1 ) * R + DP
950 */
951 MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( &R, RSA_EXPONENT_BLINDING,
952 f_rng, p_rng ) );
953 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &DP_blind, &P1, &R ) );
954 MBEDTLS_MPI_CHK( mbedtls_mpi_add_mpi( &DP_blind, &DP_blind,
955 &ctx->DP ) );
956
957 DP = &DP_blind;
958
959 /*
960 * DQ_blind = ( Q - 1 ) * R + DQ
961 */
962 MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( &R, RSA_EXPONENT_BLINDING,
963 f_rng, p_rng ) );
964 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &DQ_blind, &Q1, &R ) );
965 MBEDTLS_MPI_CHK( mbedtls_mpi_add_mpi( &DQ_blind, &DQ_blind,
966 &ctx->DQ ) );
967
968 DQ = &DQ_blind;
969#endif /* MBEDTLS_RSA_NO_CRT */
970 }
971
972#if defined(MBEDTLS_RSA_NO_CRT)
973 MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &T, &T, D, &ctx->N, &ctx->RN ) );
974#else
975 /*
976 * Faster decryption using the CRT
977 *
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100978 * TP = input ^ dP mod P
979 * TQ = input ^ dQ mod Q
Jens Wiklander817466c2018-05-22 13:49:31 +0200980 */
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100981
982 MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &TP, &T, DP, &ctx->P, &ctx->RP ) );
983 MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &TQ, &T, DQ, &ctx->Q, &ctx->RQ ) );
Jens Wiklander817466c2018-05-22 13:49:31 +0200984
985 /*
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100986 * T = (TP - TQ) * (Q^-1 mod P) mod P
Jens Wiklander817466c2018-05-22 13:49:31 +0200987 */
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100988 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &T, &TP, &TQ ) );
989 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &TP, &T, &ctx->QP ) );
990 MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &T, &TP, &ctx->P ) );
Jens Wiklander817466c2018-05-22 13:49:31 +0200991
992 /*
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100993 * T = TQ + T * Q
Jens Wiklander817466c2018-05-22 13:49:31 +0200994 */
Jens Wiklander50a57cf2019-03-13 10:41:54 +0100995 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &TP, &T, &ctx->Q ) );
996 MBEDTLS_MPI_CHK( mbedtls_mpi_add_mpi( &T, &TQ, &TP ) );
Jens Wiklander817466c2018-05-22 13:49:31 +0200997#endif /* MBEDTLS_RSA_NO_CRT */
998
999 if( f_rng != NULL )
1000 {
1001 /*
1002 * Unblind
1003 * T = T * Vf mod N
1004 */
1005 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &T, &T, &ctx->Vf ) );
1006 MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &T, &T, &ctx->N ) );
1007 }
1008
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001009 /* Verify the result to prevent glitching attacks. */
1010 MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &C, &T, &ctx->E,
1011 &ctx->N, &ctx->RN ) );
1012 if( mbedtls_mpi_cmp_mpi( &C, &I ) != 0 )
1013 {
1014 ret = MBEDTLS_ERR_RSA_VERIFY_FAILED;
1015 goto cleanup;
1016 }
1017
Jens Wiklander817466c2018-05-22 13:49:31 +02001018 olen = ctx->len;
1019 MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &T, output, olen ) );
1020
1021cleanup:
1022#if defined(MBEDTLS_THREADING_C)
1023 if( mbedtls_mutex_unlock( &ctx->mutex ) != 0 )
1024 return( MBEDTLS_ERR_THREADING_MUTEX_ERROR );
1025#endif
1026
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001027 mbedtls_mpi_free( &P1 );
1028 mbedtls_mpi_free( &Q1 );
1029 mbedtls_mpi_free( &R );
Jens Wiklander817466c2018-05-22 13:49:31 +02001030
1031 if( f_rng != NULL )
1032 {
1033#if defined(MBEDTLS_RSA_NO_CRT)
1034 mbedtls_mpi_free( &D_blind );
1035#else
1036 mbedtls_mpi_free( &DP_blind );
1037 mbedtls_mpi_free( &DQ_blind );
1038#endif
1039 }
1040
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001041 mbedtls_mpi_free( &T );
1042
1043#if !defined(MBEDTLS_RSA_NO_CRT)
1044 mbedtls_mpi_free( &TP ); mbedtls_mpi_free( &TQ );
1045#endif
1046
1047 mbedtls_mpi_free( &C );
1048 mbedtls_mpi_free( &I );
1049
Jens Wiklander817466c2018-05-22 13:49:31 +02001050 if( ret != 0 )
1051 return( MBEDTLS_ERR_RSA_PRIVATE_FAILED + ret );
1052
1053 return( 0 );
1054}
1055
1056#if defined(MBEDTLS_PKCS1_V21)
1057/**
1058 * Generate and apply the MGF1 operation (from PKCS#1 v2.1) to a buffer.
1059 *
1060 * \param dst buffer to mask
1061 * \param dlen length of destination buffer
1062 * \param src source of the mask generation
1063 * \param slen length of the source buffer
1064 * \param md_ctx message digest context to use
1065 */
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001066static int mgf_mask( unsigned char *dst, size_t dlen, unsigned char *src,
Jens Wiklander817466c2018-05-22 13:49:31 +02001067 size_t slen, mbedtls_md_context_t *md_ctx )
1068{
1069 unsigned char mask[MBEDTLS_MD_MAX_SIZE];
1070 unsigned char counter[4];
1071 unsigned char *p;
1072 unsigned int hlen;
1073 size_t i, use_len;
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001074 int ret = 0;
Jens Wiklander817466c2018-05-22 13:49:31 +02001075
1076 memset( mask, 0, MBEDTLS_MD_MAX_SIZE );
1077 memset( counter, 0, 4 );
1078
1079 hlen = mbedtls_md_get_size( md_ctx->md_info );
1080
1081 /* Generate and apply dbMask */
1082 p = dst;
1083
1084 while( dlen > 0 )
1085 {
1086 use_len = hlen;
1087 if( dlen < hlen )
1088 use_len = dlen;
1089
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001090 if( ( ret = mbedtls_md_starts( md_ctx ) ) != 0 )
1091 goto exit;
1092 if( ( ret = mbedtls_md_update( md_ctx, src, slen ) ) != 0 )
1093 goto exit;
1094 if( ( ret = mbedtls_md_update( md_ctx, counter, 4 ) ) != 0 )
1095 goto exit;
1096 if( ( ret = mbedtls_md_finish( md_ctx, mask ) ) != 0 )
1097 goto exit;
Jens Wiklander817466c2018-05-22 13:49:31 +02001098
1099 for( i = 0; i < use_len; ++i )
1100 *p++ ^= mask[i];
1101
1102 counter[3]++;
1103
1104 dlen -= use_len;
1105 }
1106
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001107exit:
1108 mbedtls_platform_zeroize( mask, sizeof( mask ) );
1109
1110 return( ret );
Jens Wiklander817466c2018-05-22 13:49:31 +02001111}
1112#endif /* MBEDTLS_PKCS1_V21 */
1113
1114#if defined(MBEDTLS_PKCS1_V21)
1115/*
1116 * Implementation of the PKCS#1 v2.1 RSAES-OAEP-ENCRYPT function
1117 */
1118int mbedtls_rsa_rsaes_oaep_encrypt( mbedtls_rsa_context *ctx,
1119 int (*f_rng)(void *, unsigned char *, size_t),
1120 void *p_rng,
1121 int mode,
1122 const unsigned char *label, size_t label_len,
1123 size_t ilen,
1124 const unsigned char *input,
1125 unsigned char *output )
1126{
1127 size_t olen;
1128 int ret;
1129 unsigned char *p = output;
1130 unsigned int hlen;
1131 const mbedtls_md_info_t *md_info;
1132 mbedtls_md_context_t md_ctx;
1133
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001134 RSA_VALIDATE_RET( ctx != NULL );
1135 RSA_VALIDATE_RET( mode == MBEDTLS_RSA_PRIVATE ||
1136 mode == MBEDTLS_RSA_PUBLIC );
1137 RSA_VALIDATE_RET( output != NULL );
1138 RSA_VALIDATE_RET( input != NULL );
1139 RSA_VALIDATE_RET( label_len == 0 || label != NULL );
1140
Jens Wiklander817466c2018-05-22 13:49:31 +02001141 if( mode == MBEDTLS_RSA_PRIVATE && ctx->padding != MBEDTLS_RSA_PKCS_V21 )
1142 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1143
1144 if( f_rng == NULL )
1145 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1146
1147 md_info = mbedtls_md_info_from_type( (mbedtls_md_type_t) ctx->hash_id );
1148 if( md_info == NULL )
1149 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1150
1151 olen = ctx->len;
1152 hlen = mbedtls_md_get_size( md_info );
1153
1154 /* first comparison checks for overflow */
1155 if( ilen + 2 * hlen + 2 < ilen || olen < ilen + 2 * hlen + 2 )
1156 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1157
1158 memset( output, 0, olen );
1159
1160 *p++ = 0;
1161
1162 /* Generate a random octet string seed */
1163 if( ( ret = f_rng( p_rng, p, hlen ) ) != 0 )
1164 return( MBEDTLS_ERR_RSA_RNG_FAILED + ret );
1165
1166 p += hlen;
1167
1168 /* Construct DB */
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001169 if( ( ret = mbedtls_md( md_info, label, label_len, p ) ) != 0 )
1170 return( ret );
Jens Wiklander817466c2018-05-22 13:49:31 +02001171 p += hlen;
1172 p += olen - 2 * hlen - 2 - ilen;
1173 *p++ = 1;
1174 memcpy( p, input, ilen );
1175
1176 mbedtls_md_init( &md_ctx );
1177 if( ( ret = mbedtls_md_setup( &md_ctx, md_info, 0 ) ) != 0 )
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001178 goto exit;
Jens Wiklander817466c2018-05-22 13:49:31 +02001179
1180 /* maskedDB: Apply dbMask to DB */
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001181 if( ( ret = mgf_mask( output + hlen + 1, olen - hlen - 1, output + 1, hlen,
1182 &md_ctx ) ) != 0 )
1183 goto exit;
Jens Wiklander817466c2018-05-22 13:49:31 +02001184
1185 /* maskedSeed: Apply seedMask to seed */
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001186 if( ( ret = mgf_mask( output + 1, hlen, output + hlen + 1, olen - hlen - 1,
1187 &md_ctx ) ) != 0 )
1188 goto exit;
Jens Wiklander817466c2018-05-22 13:49:31 +02001189
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001190exit:
Jens Wiklander817466c2018-05-22 13:49:31 +02001191 mbedtls_md_free( &md_ctx );
1192
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001193 if( ret != 0 )
1194 return( ret );
1195
Jens Wiklander817466c2018-05-22 13:49:31 +02001196 return( ( mode == MBEDTLS_RSA_PUBLIC )
1197 ? mbedtls_rsa_public( ctx, output, output )
1198 : mbedtls_rsa_private( ctx, f_rng, p_rng, output, output ) );
1199}
1200#endif /* MBEDTLS_PKCS1_V21 */
1201
1202#if defined(MBEDTLS_PKCS1_V15)
1203/*
1204 * Implementation of the PKCS#1 v2.1 RSAES-PKCS1-V1_5-ENCRYPT function
1205 */
1206int mbedtls_rsa_rsaes_pkcs1_v15_encrypt( mbedtls_rsa_context *ctx,
1207 int (*f_rng)(void *, unsigned char *, size_t),
1208 void *p_rng,
1209 int mode, size_t ilen,
1210 const unsigned char *input,
1211 unsigned char *output )
1212{
1213 size_t nb_pad, olen;
1214 int ret;
1215 unsigned char *p = output;
1216
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001217 RSA_VALIDATE_RET( ctx != NULL );
1218 RSA_VALIDATE_RET( mode == MBEDTLS_RSA_PRIVATE ||
1219 mode == MBEDTLS_RSA_PUBLIC );
1220 RSA_VALIDATE_RET( output != NULL );
1221 RSA_VALIDATE_RET( input != NULL );
Jens Wiklander817466c2018-05-22 13:49:31 +02001222
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001223 if( mode == MBEDTLS_RSA_PRIVATE && ctx->padding != MBEDTLS_RSA_PKCS_V15 )
Jens Wiklander817466c2018-05-22 13:49:31 +02001224 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1225
1226 olen = ctx->len;
1227
1228 /* first comparison checks for overflow */
1229 if( ilen + 11 < ilen || olen < ilen + 11 )
1230 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1231
1232 nb_pad = olen - 3 - ilen;
1233
1234 *p++ = 0;
1235 if( mode == MBEDTLS_RSA_PUBLIC )
1236 {
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001237 if( f_rng == NULL )
1238 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1239
Jens Wiklander817466c2018-05-22 13:49:31 +02001240 *p++ = MBEDTLS_RSA_CRYPT;
1241
1242 while( nb_pad-- > 0 )
1243 {
1244 int rng_dl = 100;
1245
1246 do {
1247 ret = f_rng( p_rng, p, 1 );
1248 } while( *p == 0 && --rng_dl && ret == 0 );
1249
1250 /* Check if RNG failed to generate data */
1251 if( rng_dl == 0 || ret != 0 )
1252 return( MBEDTLS_ERR_RSA_RNG_FAILED + ret );
1253
1254 p++;
1255 }
1256 }
1257 else
1258 {
1259 *p++ = MBEDTLS_RSA_SIGN;
1260
1261 while( nb_pad-- > 0 )
1262 *p++ = 0xFF;
1263 }
1264
1265 *p++ = 0;
1266 memcpy( p, input, ilen );
1267
1268 return( ( mode == MBEDTLS_RSA_PUBLIC )
1269 ? mbedtls_rsa_public( ctx, output, output )
1270 : mbedtls_rsa_private( ctx, f_rng, p_rng, output, output ) );
1271}
1272#endif /* MBEDTLS_PKCS1_V15 */
1273
1274/*
1275 * Add the message padding, then do an RSA operation
1276 */
1277int mbedtls_rsa_pkcs1_encrypt( mbedtls_rsa_context *ctx,
1278 int (*f_rng)(void *, unsigned char *, size_t),
1279 void *p_rng,
1280 int mode, size_t ilen,
1281 const unsigned char *input,
1282 unsigned char *output )
1283{
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001284 RSA_VALIDATE_RET( ctx != NULL );
1285 RSA_VALIDATE_RET( mode == MBEDTLS_RSA_PRIVATE ||
1286 mode == MBEDTLS_RSA_PUBLIC );
1287 RSA_VALIDATE_RET( output != NULL );
1288 RSA_VALIDATE_RET( input != NULL );
1289
Jens Wiklander817466c2018-05-22 13:49:31 +02001290 switch( ctx->padding )
1291 {
1292#if defined(MBEDTLS_PKCS1_V15)
1293 case MBEDTLS_RSA_PKCS_V15:
1294 return mbedtls_rsa_rsaes_pkcs1_v15_encrypt( ctx, f_rng, p_rng, mode, ilen,
1295 input, output );
1296#endif
1297
1298#if defined(MBEDTLS_PKCS1_V21)
1299 case MBEDTLS_RSA_PKCS_V21:
1300 return mbedtls_rsa_rsaes_oaep_encrypt( ctx, f_rng, p_rng, mode, NULL, 0,
1301 ilen, input, output );
1302#endif
1303
1304 default:
1305 return( MBEDTLS_ERR_RSA_INVALID_PADDING );
1306 }
1307}
1308
1309#if defined(MBEDTLS_PKCS1_V21)
1310/*
1311 * Implementation of the PKCS#1 v2.1 RSAES-OAEP-DECRYPT function
1312 */
1313int mbedtls_rsa_rsaes_oaep_decrypt( mbedtls_rsa_context *ctx,
1314 int (*f_rng)(void *, unsigned char *, size_t),
1315 void *p_rng,
1316 int mode,
1317 const unsigned char *label, size_t label_len,
1318 size_t *olen,
1319 const unsigned char *input,
1320 unsigned char *output,
1321 size_t output_max_len )
1322{
1323 int ret;
1324 size_t ilen, i, pad_len;
1325 unsigned char *p, bad, pad_done;
1326 unsigned char buf[MBEDTLS_MPI_MAX_SIZE];
1327 unsigned char lhash[MBEDTLS_MD_MAX_SIZE];
1328 unsigned int hlen;
1329 const mbedtls_md_info_t *md_info;
1330 mbedtls_md_context_t md_ctx;
1331
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001332 RSA_VALIDATE_RET( ctx != NULL );
1333 RSA_VALIDATE_RET( mode == MBEDTLS_RSA_PRIVATE ||
1334 mode == MBEDTLS_RSA_PUBLIC );
1335 RSA_VALIDATE_RET( output_max_len == 0 || output != NULL );
1336 RSA_VALIDATE_RET( label_len == 0 || label != NULL );
1337 RSA_VALIDATE_RET( input != NULL );
1338 RSA_VALIDATE_RET( olen != NULL );
1339
Jens Wiklander817466c2018-05-22 13:49:31 +02001340 /*
1341 * Parameters sanity checks
1342 */
1343 if( mode == MBEDTLS_RSA_PRIVATE && ctx->padding != MBEDTLS_RSA_PKCS_V21 )
1344 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1345
1346 ilen = ctx->len;
1347
1348 if( ilen < 16 || ilen > sizeof( buf ) )
1349 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1350
1351 md_info = mbedtls_md_info_from_type( (mbedtls_md_type_t) ctx->hash_id );
1352 if( md_info == NULL )
1353 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1354
1355 hlen = mbedtls_md_get_size( md_info );
1356
1357 // checking for integer underflow
1358 if( 2 * hlen + 2 > ilen )
1359 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1360
1361 /*
1362 * RSA operation
1363 */
Summer Qinb95a6c52017-12-15 11:27:56 +08001364 if( ctx->P.n == 0 )
1365 ret = ( mode == MBEDTLS_RSA_PUBLIC )
1366 ? mbedtls_rsa_public( ctx, input, buf )
1367 : mbedtls_rsa_private( ctx, NULL, NULL, input, buf );
1368 else
1369 ret = ( mode == MBEDTLS_RSA_PUBLIC )
1370 ? mbedtls_rsa_public( ctx, input, buf )
1371 : mbedtls_rsa_private( ctx, f_rng, p_rng, input, buf );
Jens Wiklander817466c2018-05-22 13:49:31 +02001372
1373 if( ret != 0 )
1374 goto cleanup;
1375
1376 /*
1377 * Unmask data and generate lHash
1378 */
1379 mbedtls_md_init( &md_ctx );
1380 if( ( ret = mbedtls_md_setup( &md_ctx, md_info, 0 ) ) != 0 )
1381 {
1382 mbedtls_md_free( &md_ctx );
1383 goto cleanup;
1384 }
1385
Jens Wiklander817466c2018-05-22 13:49:31 +02001386 /* seed: Apply seedMask to maskedSeed */
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001387 if( ( ret = mgf_mask( buf + 1, hlen, buf + hlen + 1, ilen - hlen - 1,
1388 &md_ctx ) ) != 0 ||
Jens Wiklander817466c2018-05-22 13:49:31 +02001389 /* DB: Apply dbMask to maskedDB */
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001390 ( ret = mgf_mask( buf + hlen + 1, ilen - hlen - 1, buf + 1, hlen,
1391 &md_ctx ) ) != 0 )
1392 {
1393 mbedtls_md_free( &md_ctx );
1394 goto cleanup;
1395 }
Jens Wiklander817466c2018-05-22 13:49:31 +02001396
1397 mbedtls_md_free( &md_ctx );
1398
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001399 /* Generate lHash */
1400 if( ( ret = mbedtls_md( md_info, label, label_len, lhash ) ) != 0 )
1401 goto cleanup;
1402
Jens Wiklander817466c2018-05-22 13:49:31 +02001403 /*
1404 * Check contents, in "constant-time"
1405 */
1406 p = buf;
1407 bad = 0;
1408
1409 bad |= *p++; /* First byte must be 0 */
1410
1411 p += hlen; /* Skip seed */
1412
1413 /* Check lHash */
1414 for( i = 0; i < hlen; i++ )
1415 bad |= lhash[i] ^ *p++;
1416
1417 /* Get zero-padding len, but always read till end of buffer
1418 * (minus one, for the 01 byte) */
1419 pad_len = 0;
1420 pad_done = 0;
1421 for( i = 0; i < ilen - 2 * hlen - 2; i++ )
1422 {
1423 pad_done |= p[i];
1424 pad_len += ((pad_done | (unsigned char)-pad_done) >> 7) ^ 1;
1425 }
1426
1427 p += pad_len;
1428 bad |= *p++ ^ 0x01;
1429
1430 /*
1431 * The only information "leaked" is whether the padding was correct or not
1432 * (eg, no data is copied if it was not correct). This meets the
1433 * recommendations in PKCS#1 v2.2: an opponent cannot distinguish between
1434 * the different error conditions.
1435 */
1436 if( bad != 0 )
1437 {
1438 ret = MBEDTLS_ERR_RSA_INVALID_PADDING;
1439 goto cleanup;
1440 }
1441
1442 if( ilen - ( p - buf ) > output_max_len )
1443 {
1444 ret = MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE;
1445 goto cleanup;
1446 }
1447
1448 *olen = ilen - (p - buf);
1449 memcpy( output, p, *olen );
1450 ret = 0;
1451
1452cleanup:
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001453 mbedtls_platform_zeroize( buf, sizeof( buf ) );
1454 mbedtls_platform_zeroize( lhash, sizeof( lhash ) );
Jens Wiklander817466c2018-05-22 13:49:31 +02001455
1456 return( ret );
1457}
1458#endif /* MBEDTLS_PKCS1_V21 */
1459
1460#if defined(MBEDTLS_PKCS1_V15)
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001461/** Turn zero-or-nonzero into zero-or-all-bits-one, without branches.
1462 *
1463 * \param value The value to analyze.
1464 * \return Zero if \p value is zero, otherwise all-bits-one.
1465 */
1466static unsigned all_or_nothing_int( unsigned value )
1467{
1468 /* MSVC has a warning about unary minus on unsigned, but this is
1469 * well-defined and precisely what we want to do here */
1470#if defined(_MSC_VER)
1471#pragma warning( push )
1472#pragma warning( disable : 4146 )
1473#endif
1474 return( - ( ( value | - value ) >> ( sizeof( value ) * 8 - 1 ) ) );
1475#if defined(_MSC_VER)
1476#pragma warning( pop )
1477#endif
1478}
1479
1480/** Check whether a size is out of bounds, without branches.
1481 *
1482 * This is equivalent to `size > max`, but is likely to be compiled to
1483 * to code using bitwise operation rather than a branch.
1484 *
1485 * \param size Size to check.
1486 * \param max Maximum desired value for \p size.
1487 * \return \c 0 if `size <= max`.
1488 * \return \c 1 if `size > max`.
1489 */
1490static unsigned size_greater_than( size_t size, size_t max )
1491{
1492 /* Return the sign bit (1 for negative) of (max - size). */
1493 return( ( max - size ) >> ( sizeof( size_t ) * 8 - 1 ) );
1494}
1495
1496/** Choose between two integer values, without branches.
1497 *
1498 * This is equivalent to `cond ? if1 : if0`, but is likely to be compiled
1499 * to code using bitwise operation rather than a branch.
1500 *
1501 * \param cond Condition to test.
1502 * \param if1 Value to use if \p cond is nonzero.
1503 * \param if0 Value to use if \p cond is zero.
1504 * \return \c if1 if \p cond is nonzero, otherwise \c if0.
1505 */
1506static unsigned if_int( unsigned cond, unsigned if1, unsigned if0 )
1507{
1508 unsigned mask = all_or_nothing_int( cond );
1509 return( ( mask & if1 ) | (~mask & if0 ) );
1510}
1511
1512/** Shift some data towards the left inside a buffer without leaking
1513 * the length of the data through side channels.
1514 *
1515 * `mem_move_to_left(start, total, offset)` is functionally equivalent to
1516 * ```
1517 * memmove(start, start + offset, total - offset);
1518 * memset(start + offset, 0, total - offset);
1519 * ```
1520 * but it strives to use a memory access pattern (and thus total timing)
1521 * that does not depend on \p offset. This timing independence comes at
1522 * the expense of performance.
1523 *
1524 * \param start Pointer to the start of the buffer.
1525 * \param total Total size of the buffer.
1526 * \param offset Offset from which to copy \p total - \p offset bytes.
1527 */
1528static void mem_move_to_left( void *start,
1529 size_t total,
1530 size_t offset )
1531{
1532 volatile unsigned char *buf = start;
1533 size_t i, n;
1534 if( total == 0 )
1535 return;
1536 for( i = 0; i < total; i++ )
1537 {
1538 unsigned no_op = size_greater_than( total - offset, i );
1539 /* The first `total - offset` passes are a no-op. The last
1540 * `offset` passes shift the data one byte to the left and
1541 * zero out the last byte. */
1542 for( n = 0; n < total - 1; n++ )
1543 {
1544 unsigned char current = buf[n];
1545 unsigned char next = buf[n+1];
1546 buf[n] = if_int( no_op, current, next );
1547 }
1548 buf[total-1] = if_int( no_op, buf[total-1], 0 );
1549 }
1550}
1551
Jens Wiklander817466c2018-05-22 13:49:31 +02001552/*
1553 * Implementation of the PKCS#1 v2.1 RSAES-PKCS1-V1_5-DECRYPT function
1554 */
1555int mbedtls_rsa_rsaes_pkcs1_v15_decrypt( mbedtls_rsa_context *ctx,
1556 int (*f_rng)(void *, unsigned char *, size_t),
1557 void *p_rng,
1558 int mode, size_t *olen,
1559 const unsigned char *input,
1560 unsigned char *output,
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001561 size_t output_max_len )
Jens Wiklander817466c2018-05-22 13:49:31 +02001562{
1563 int ret;
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001564 size_t ilen, i, plaintext_max_size;
Jens Wiklander817466c2018-05-22 13:49:31 +02001565 unsigned char buf[MBEDTLS_MPI_MAX_SIZE];
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001566 /* The following variables take sensitive values: their value must
1567 * not leak into the observable behavior of the function other than
1568 * the designated outputs (output, olen, return value). Otherwise
1569 * this would open the execution of the function to
1570 * side-channel-based variants of the Bleichenbacher padding oracle
1571 * attack. Potential side channels include overall timing, memory
1572 * access patterns (especially visible to an adversary who has access
1573 * to a shared memory cache), and branches (especially visible to
1574 * an adversary who has access to a shared code cache or to a shared
1575 * branch predictor). */
1576 size_t pad_count = 0;
1577 unsigned bad = 0;
1578 unsigned char pad_done = 0;
1579 size_t plaintext_size = 0;
1580 unsigned output_too_large;
1581
1582 RSA_VALIDATE_RET( ctx != NULL );
1583 RSA_VALIDATE_RET( mode == MBEDTLS_RSA_PRIVATE ||
1584 mode == MBEDTLS_RSA_PUBLIC );
1585 RSA_VALIDATE_RET( output_max_len == 0 || output != NULL );
1586 RSA_VALIDATE_RET( input != NULL );
1587 RSA_VALIDATE_RET( olen != NULL );
1588
1589 ilen = ctx->len;
1590 plaintext_max_size = ( output_max_len > ilen - 11 ?
1591 ilen - 11 :
1592 output_max_len );
Jens Wiklander817466c2018-05-22 13:49:31 +02001593
1594 if( mode == MBEDTLS_RSA_PRIVATE && ctx->padding != MBEDTLS_RSA_PKCS_V15 )
1595 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1596
Jens Wiklander817466c2018-05-22 13:49:31 +02001597 if( ilen < 16 || ilen > sizeof( buf ) )
1598 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1599
1600 ret = ( mode == MBEDTLS_RSA_PUBLIC )
1601 ? mbedtls_rsa_public( ctx, input, buf )
1602 : mbedtls_rsa_private( ctx, f_rng, p_rng, input, buf );
1603
1604 if( ret != 0 )
1605 goto cleanup;
1606
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001607 /* Check and get padding length in constant time and constant
1608 * memory trace. The first byte must be 0. */
1609 bad |= buf[0];
Jens Wiklander817466c2018-05-22 13:49:31 +02001610
Jens Wiklander817466c2018-05-22 13:49:31 +02001611 if( mode == MBEDTLS_RSA_PRIVATE )
1612 {
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001613 /* Decode EME-PKCS1-v1_5 padding: 0x00 || 0x02 || PS || 0x00
1614 * where PS must be at least 8 nonzero bytes. */
1615 bad |= buf[1] ^ MBEDTLS_RSA_CRYPT;
Jens Wiklander817466c2018-05-22 13:49:31 +02001616
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001617 /* Read the whole buffer. Set pad_done to nonzero if we find
1618 * the 0x00 byte and remember the padding length in pad_count. */
1619 for( i = 2; i < ilen; i++ )
Jens Wiklander817466c2018-05-22 13:49:31 +02001620 {
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001621 pad_done |= ((buf[i] | (unsigned char)-buf[i]) >> 7) ^ 1;
Jens Wiklander817466c2018-05-22 13:49:31 +02001622 pad_count += ((pad_done | (unsigned char)-pad_done) >> 7) ^ 1;
1623 }
Jens Wiklander817466c2018-05-22 13:49:31 +02001624 }
1625 else
1626 {
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001627 /* Decode EMSA-PKCS1-v1_5 padding: 0x00 || 0x01 || PS || 0x00
1628 * where PS must be at least 8 bytes with the value 0xFF. */
1629 bad |= buf[1] ^ MBEDTLS_RSA_SIGN;
Jens Wiklander817466c2018-05-22 13:49:31 +02001630
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001631 /* Read the whole buffer. Set pad_done to nonzero if we find
1632 * the 0x00 byte and remember the padding length in pad_count.
1633 * If there's a non-0xff byte in the padding, the padding is bad. */
1634 for( i = 2; i < ilen; i++ )
Jens Wiklander817466c2018-05-22 13:49:31 +02001635 {
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001636 pad_done |= if_int( buf[i], 0, 1 );
1637 pad_count += if_int( pad_done, 0, 1 );
1638 bad |= if_int( pad_done, 0, buf[i] ^ 0xFF );
Jens Wiklander817466c2018-05-22 13:49:31 +02001639 }
Jens Wiklander817466c2018-05-22 13:49:31 +02001640 }
1641
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001642 /* If pad_done is still zero, there's no data, only unfinished padding. */
1643 bad |= if_int( pad_done, 0, 1 );
Jens Wiklander817466c2018-05-22 13:49:31 +02001644
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001645 /* There must be at least 8 bytes of padding. */
1646 bad |= size_greater_than( 8, pad_count );
Jens Wiklander817466c2018-05-22 13:49:31 +02001647
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001648 /* If the padding is valid, set plaintext_size to the number of
1649 * remaining bytes after stripping the padding. If the padding
1650 * is invalid, avoid leaking this fact through the size of the
1651 * output: use the maximum message size that fits in the output
1652 * buffer. Do it without branches to avoid leaking the padding
1653 * validity through timing. RSA keys are small enough that all the
1654 * size_t values involved fit in unsigned int. */
1655 plaintext_size = if_int( bad,
1656 (unsigned) plaintext_max_size,
1657 (unsigned) ( ilen - pad_count - 3 ) );
Jens Wiklander817466c2018-05-22 13:49:31 +02001658
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001659 /* Set output_too_large to 0 if the plaintext fits in the output
1660 * buffer and to 1 otherwise. */
1661 output_too_large = size_greater_than( plaintext_size,
1662 plaintext_max_size );
1663
1664 /* Set ret without branches to avoid timing attacks. Return:
1665 * - INVALID_PADDING if the padding is bad (bad != 0).
1666 * - OUTPUT_TOO_LARGE if the padding is good but the decrypted
1667 * plaintext does not fit in the output buffer.
1668 * - 0 if the padding is correct. */
1669 ret = - (int) if_int( bad, - MBEDTLS_ERR_RSA_INVALID_PADDING,
1670 if_int( output_too_large, - MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE,
1671 0 ) );
1672
1673 /* If the padding is bad or the plaintext is too large, zero the
1674 * data that we're about to copy to the output buffer.
1675 * We need to copy the same amount of data
1676 * from the same buffer whether the padding is good or not to
1677 * avoid leaking the padding validity through overall timing or
1678 * through memory or cache access patterns. */
1679 bad = all_or_nothing_int( bad | output_too_large );
1680 for( i = 11; i < ilen; i++ )
1681 buf[i] &= ~bad;
1682
1683 /* If the plaintext is too large, truncate it to the buffer size.
1684 * Copy anyway to avoid revealing the length through timing, because
1685 * revealing the length is as bad as revealing the padding validity
1686 * for a Bleichenbacher attack. */
1687 plaintext_size = if_int( output_too_large,
1688 (unsigned) plaintext_max_size,
1689 (unsigned) plaintext_size );
1690
1691 /* Move the plaintext to the leftmost position where it can start in
1692 * the working buffer, i.e. make it start plaintext_max_size from
1693 * the end of the buffer. Do this with a memory access trace that
1694 * does not depend on the plaintext size. After this move, the
1695 * starting location of the plaintext is no longer sensitive
1696 * information. */
1697 mem_move_to_left( buf + ilen - plaintext_max_size,
1698 plaintext_max_size,
1699 plaintext_max_size - plaintext_size );
1700
1701 /* Finally copy the decrypted plaintext plus trailing zeros
1702 * into the output buffer. */
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;
Jens Wiklander817466c2018-05-22 13:49:31 +02001710
1711cleanup:
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001712 mbedtls_platform_zeroize( buf, sizeof( buf ) );
Jens Wiklander817466c2018-05-22 13:49:31 +02001713
1714 return( ret );
1715}
1716#endif /* MBEDTLS_PKCS1_V15 */
1717
1718/*
1719 * Do an RSA operation, then remove the message padding
1720 */
1721int mbedtls_rsa_pkcs1_decrypt( mbedtls_rsa_context *ctx,
1722 int (*f_rng)(void *, unsigned char *, size_t),
1723 void *p_rng,
1724 int mode, size_t *olen,
1725 const unsigned char *input,
1726 unsigned char *output,
1727 size_t output_max_len)
1728{
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001729 RSA_VALIDATE_RET( ctx != NULL );
1730 RSA_VALIDATE_RET( mode == MBEDTLS_RSA_PRIVATE ||
1731 mode == MBEDTLS_RSA_PUBLIC );
1732 RSA_VALIDATE_RET( output_max_len == 0 || output != NULL );
1733 RSA_VALIDATE_RET( input != NULL );
1734 RSA_VALIDATE_RET( olen != NULL );
1735
Jens Wiklander817466c2018-05-22 13:49:31 +02001736 switch( ctx->padding )
1737 {
1738#if defined(MBEDTLS_PKCS1_V15)
1739 case MBEDTLS_RSA_PKCS_V15:
1740 return mbedtls_rsa_rsaes_pkcs1_v15_decrypt( ctx, f_rng, p_rng, mode, olen,
1741 input, output, output_max_len );
1742#endif
1743
1744#if defined(MBEDTLS_PKCS1_V21)
1745 case MBEDTLS_RSA_PKCS_V21:
1746 return mbedtls_rsa_rsaes_oaep_decrypt( ctx, f_rng, p_rng, mode, NULL, 0,
1747 olen, input, output,
1748 output_max_len );
1749#endif
1750
1751 default:
1752 return( MBEDTLS_ERR_RSA_INVALID_PADDING );
1753 }
1754}
1755
1756#if defined(MBEDTLS_PKCS1_V21)
1757/*
1758 * Implementation of the PKCS#1 v2.1 RSASSA-PSS-SIGN function
1759 */
1760int mbedtls_rsa_rsassa_pss_sign( mbedtls_rsa_context *ctx,
1761 int (*f_rng)(void *, unsigned char *, size_t),
1762 void *p_rng,
1763 int mode,
1764 mbedtls_md_type_t md_alg,
1765 unsigned int hashlen,
1766 const unsigned char *hash,
1767 unsigned char *sig )
1768{
1769 size_t olen;
1770 unsigned char *p = sig;
1771 unsigned char salt[MBEDTLS_MD_MAX_SIZE];
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001772 size_t slen, min_slen, hlen, offset = 0;
Jens Wiklander817466c2018-05-22 13:49:31 +02001773 int ret;
1774 size_t msb;
1775 const mbedtls_md_info_t *md_info;
1776 mbedtls_md_context_t md_ctx;
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001777 RSA_VALIDATE_RET( ctx != NULL );
1778 RSA_VALIDATE_RET( mode == MBEDTLS_RSA_PRIVATE ||
1779 mode == MBEDTLS_RSA_PUBLIC );
1780 RSA_VALIDATE_RET( ( md_alg == MBEDTLS_MD_NONE &&
1781 hashlen == 0 ) ||
1782 hash != NULL );
1783 RSA_VALIDATE_RET( sig != NULL );
Jens Wiklander817466c2018-05-22 13:49:31 +02001784
1785 if( mode == MBEDTLS_RSA_PRIVATE && ctx->padding != MBEDTLS_RSA_PKCS_V21 )
1786 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1787
1788 if( f_rng == NULL )
1789 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1790
1791 olen = ctx->len;
1792
1793 if( md_alg != MBEDTLS_MD_NONE )
1794 {
1795 /* Gather length of hash to sign */
1796 md_info = mbedtls_md_info_from_type( md_alg );
1797 if( md_info == NULL )
1798 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1799
1800 hashlen = mbedtls_md_get_size( md_info );
1801 }
1802
1803 md_info = mbedtls_md_info_from_type( (mbedtls_md_type_t) ctx->hash_id );
1804 if( md_info == NULL )
1805 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1806
1807 hlen = mbedtls_md_get_size( md_info );
Jens Wiklander817466c2018-05-22 13:49:31 +02001808
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001809 /* Calculate the largest possible salt length. Normally this is the hash
1810 * length, which is the maximum length the salt can have. If there is not
1811 * enough room, use the maximum salt length that fits. The constraint is
1812 * that the hash length plus the salt length plus 2 bytes must be at most
1813 * the key length. This complies with FIPS 186-4 §5.5 (e) and RFC 8017
1814 * (PKCS#1 v2.2) §9.1.1 step 3. */
1815 min_slen = hlen - 2;
1816 if( olen < hlen + min_slen + 2 )
Jens Wiklander817466c2018-05-22 13:49:31 +02001817 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001818 else if( olen >= hlen + hlen + 2 )
1819 slen = hlen;
1820 else
1821 slen = olen - hlen - 2;
Jens Wiklander817466c2018-05-22 13:49:31 +02001822
1823 memset( sig, 0, olen );
1824
1825 /* Generate salt of length slen */
1826 if( ( ret = f_rng( p_rng, salt, slen ) ) != 0 )
1827 return( MBEDTLS_ERR_RSA_RNG_FAILED + ret );
1828
1829 /* Note: EMSA-PSS encoding is over the length of N - 1 bits */
1830 msb = mbedtls_mpi_bitlen( &ctx->N ) - 1;
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001831 p += olen - hlen - slen - 2;
Jens Wiklander817466c2018-05-22 13:49:31 +02001832 *p++ = 0x01;
1833 memcpy( p, salt, slen );
1834 p += slen;
1835
1836 mbedtls_md_init( &md_ctx );
1837 if( ( ret = mbedtls_md_setup( &md_ctx, md_info, 0 ) ) != 0 )
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001838 goto exit;
Jens Wiklander817466c2018-05-22 13:49:31 +02001839
1840 /* Generate H = Hash( M' ) */
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001841 if( ( ret = mbedtls_md_starts( &md_ctx ) ) != 0 )
1842 goto exit;
1843 if( ( ret = mbedtls_md_update( &md_ctx, p, 8 ) ) != 0 )
1844 goto exit;
1845 if( ( ret = mbedtls_md_update( &md_ctx, hash, hashlen ) ) != 0 )
1846 goto exit;
1847 if( ( ret = mbedtls_md_update( &md_ctx, salt, slen ) ) != 0 )
1848 goto exit;
1849 if( ( ret = mbedtls_md_finish( &md_ctx, p ) ) != 0 )
1850 goto exit;
Jens Wiklander817466c2018-05-22 13:49:31 +02001851
1852 /* Compensate for boundary condition when applying mask */
1853 if( msb % 8 == 0 )
1854 offset = 1;
1855
1856 /* maskedDB: Apply dbMask to DB */
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001857 if( ( ret = mgf_mask( sig + offset, olen - hlen - 1 - offset, p, hlen,
1858 &md_ctx ) ) != 0 )
1859 goto exit;
Jens Wiklander817466c2018-05-22 13:49:31 +02001860
1861 msb = mbedtls_mpi_bitlen( &ctx->N ) - 1;
1862 sig[0] &= 0xFF >> ( olen * 8 - msb );
1863
1864 p += hlen;
1865 *p++ = 0xBC;
1866
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001867 mbedtls_platform_zeroize( salt, sizeof( salt ) );
1868
1869exit:
1870 mbedtls_md_free( &md_ctx );
1871
1872 if( ret != 0 )
1873 return( ret );
1874
Summer Qinb95a6c52017-12-15 11:27:56 +08001875 if( ctx->P.n == 0)
1876 return( ( mode == MBEDTLS_RSA_PUBLIC )
1877 ? mbedtls_rsa_public( ctx, sig, sig )
1878 : mbedtls_rsa_private( ctx, NULL, NULL, sig, sig ) );
1879 else
1880 return( ( mode == MBEDTLS_RSA_PUBLIC )
1881 ? mbedtls_rsa_public( ctx, sig, sig )
1882 : mbedtls_rsa_private( ctx, f_rng, p_rng, sig, sig ) );
Jens Wiklander817466c2018-05-22 13:49:31 +02001883}
1884#endif /* MBEDTLS_PKCS1_V21 */
1885
1886#if defined(MBEDTLS_PKCS1_V15)
1887/*
1888 * Implementation of the PKCS#1 v2.1 RSASSA-PKCS1-V1_5-SIGN function
1889 */
Jens Wiklander50a57cf2019-03-13 10:41:54 +01001890
1891/* Construct a PKCS v1.5 encoding of a hashed message
1892 *
1893 * This is used both for signature generation and verification.
1894 *
1895 * Parameters:
1896 * - md_alg: Identifies the hash algorithm used to generate the given hash;
1897 * MBEDTLS_MD_NONE if raw data is signed.
1898 * - hashlen: Length of hash in case hashlen is MBEDTLS_MD_NONE.
1899 * - hash: Buffer containing the hashed message or the raw data.
1900 * - dst_len: Length of the encoded message.
1901 * - dst: Buffer to hold the encoded message.
1902 *
1903 * Assumptions:
1904 * - hash has size hashlen if md_alg == MBEDTLS_MD_NONE.
1905 * - hash has size corresponding to md_alg if md_alg != MBEDTLS_MD_NONE.
1906 * - dst points to a buffer of size at least dst_len.
1907 *
1908 */
1909static int rsa_rsassa_pkcs1_v15_encode( mbedtls_md_type_t md_alg,
1910 unsigned int hashlen,
1911 const unsigned char *hash,
1912 size_t dst_len,
1913 unsigned char *dst )
1914{
1915 size_t oid_size = 0;
1916 size_t nb_pad = dst_len;
1917 unsigned char *p = dst;
1918 const char *oid = NULL;
1919
1920 /* Are we signing hashed or raw data? */
1921 if( md_alg != MBEDTLS_MD_NONE )
1922 {
1923 const mbedtls_md_info_t *md_info = mbedtls_md_info_from_type( md_alg );
1924 if( md_info == NULL )
1925 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1926
1927 if( mbedtls_oid_get_oid_by_md( md_alg, &oid, &oid_size ) != 0 )
1928 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1929
1930 hashlen = mbedtls_md_get_size( md_info );
1931
1932 /* Double-check that 8 + hashlen + oid_size can be used as a
1933 * 1-byte ASN.1 length encoding and that there's no overflow. */
1934 if( 8 + hashlen + oid_size >= 0x80 ||
1935 10 + hashlen < hashlen ||
1936 10 + hashlen + oid_size < 10 + hashlen )
1937 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1938
1939 /*
1940 * Static bounds check:
1941 * - Need 10 bytes for five tag-length pairs.
1942 * (Insist on 1-byte length encodings to protect against variants of
1943 * Bleichenbacher's forgery attack against lax PKCS#1v1.5 verification)
1944 * - Need hashlen bytes for hash
1945 * - Need oid_size bytes for hash alg OID.
1946 */
1947 if( nb_pad < 10 + hashlen + oid_size )
1948 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1949 nb_pad -= 10 + hashlen + oid_size;
1950 }
1951 else
1952 {
1953 if( nb_pad < hashlen )
1954 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1955
1956 nb_pad -= hashlen;
1957 }
1958
1959 /* Need space for signature header and padding delimiter (3 bytes),
1960 * and 8 bytes for the minimal padding */
1961 if( nb_pad < 3 + 8 )
1962 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
1963 nb_pad -= 3;
1964
1965 /* Now nb_pad is the amount of memory to be filled
1966 * with padding, and at least 8 bytes long. */
1967
1968 /* Write signature header and padding */
1969 *p++ = 0;
1970 *p++ = MBEDTLS_RSA_SIGN;
1971 memset( p, 0xFF, nb_pad );
1972 p += nb_pad;
1973 *p++ = 0;
1974
1975 /* Are we signing raw data? */
1976 if( md_alg == MBEDTLS_MD_NONE )
1977 {
1978 memcpy( p, hash, hashlen );
1979 return( 0 );
1980 }
1981
1982 /* Signing hashed data, add corresponding ASN.1 structure
1983 *
1984 * DigestInfo ::= SEQUENCE {
1985 * digestAlgorithm DigestAlgorithmIdentifier,
1986 * digest Digest }
1987 * DigestAlgorithmIdentifier ::= AlgorithmIdentifier
1988 * Digest ::= OCTET STRING
1989 *
1990 * Schematic:
1991 * TAG-SEQ + LEN [ TAG-SEQ + LEN [ TAG-OID + LEN [ OID ]
1992 * TAG-NULL + LEN [ NULL ] ]
1993 * TAG-OCTET + LEN [ HASH ] ]
1994 */
1995 *p++ = MBEDTLS_ASN1_SEQUENCE | MBEDTLS_ASN1_CONSTRUCTED;
1996 *p++ = (unsigned char)( 0x08 + oid_size + hashlen );
1997 *p++ = MBEDTLS_ASN1_SEQUENCE | MBEDTLS_ASN1_CONSTRUCTED;
1998 *p++ = (unsigned char)( 0x04 + oid_size );
1999 *p++ = MBEDTLS_ASN1_OID;
2000 *p++ = (unsigned char) oid_size;
2001 memcpy( p, oid, oid_size );
2002 p += oid_size;
2003 *p++ = MBEDTLS_ASN1_NULL;
2004 *p++ = 0x00;
2005 *p++ = MBEDTLS_ASN1_OCTET_STRING;
2006 *p++ = (unsigned char) hashlen;
2007 memcpy( p, hash, hashlen );
2008 p += hashlen;
2009
2010 /* Just a sanity-check, should be automatic
2011 * after the initial bounds check. */
2012 if( p != dst + dst_len )
2013 {
2014 mbedtls_platform_zeroize( dst, dst_len );
2015 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
2016 }
2017
2018 return( 0 );
2019}
2020
Jens Wiklander817466c2018-05-22 13:49:31 +02002021/*
2022 * Do an RSA operation to sign the message digest
2023 */
2024int mbedtls_rsa_rsassa_pkcs1_v15_sign( mbedtls_rsa_context *ctx,
2025 int (*f_rng)(void *, unsigned char *, size_t),
2026 void *p_rng,
2027 int mode,
2028 mbedtls_md_type_t md_alg,
2029 unsigned int hashlen,
2030 const unsigned char *hash,
2031 unsigned char *sig )
2032{
Jens Wiklander817466c2018-05-22 13:49:31 +02002033 int ret;
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002034 unsigned char *sig_try = NULL, *verif = NULL;
2035
2036 RSA_VALIDATE_RET( ctx != NULL );
2037 RSA_VALIDATE_RET( mode == MBEDTLS_RSA_PRIVATE ||
2038 mode == MBEDTLS_RSA_PUBLIC );
2039 RSA_VALIDATE_RET( ( md_alg == MBEDTLS_MD_NONE &&
2040 hashlen == 0 ) ||
2041 hash != NULL );
2042 RSA_VALIDATE_RET( sig != NULL );
Jens Wiklander817466c2018-05-22 13:49:31 +02002043
2044 if( mode == MBEDTLS_RSA_PRIVATE && ctx->padding != MBEDTLS_RSA_PKCS_V15 )
2045 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
2046
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002047 /*
2048 * Prepare PKCS1-v1.5 encoding (padding and hash identifier)
2049 */
Jens Wiklander817466c2018-05-22 13:49:31 +02002050
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002051 if( ( ret = rsa_rsassa_pkcs1_v15_encode( md_alg, hashlen, hash,
2052 ctx->len, sig ) ) != 0 )
2053 return( ret );
Jens Wiklander817466c2018-05-22 13:49:31 +02002054
2055 /*
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002056 * Call respective RSA primitive
2057 */
2058
2059 if( mode == MBEDTLS_RSA_PUBLIC )
2060 {
2061 /* Skip verification on a public key operation */
2062 return( mbedtls_rsa_public( ctx, sig, sig ) );
2063 }
2064
2065 /* Private key operation
2066 *
Jens Wiklander817466c2018-05-22 13:49:31 +02002067 * In order to prevent Lenstra's attack, make the signature in a
2068 * temporary buffer and check it before returning it.
2069 */
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002070
Jens Wiklander817466c2018-05-22 13:49:31 +02002071 sig_try = mbedtls_calloc( 1, ctx->len );
2072 if( sig_try == NULL )
2073 return( MBEDTLS_ERR_MPI_ALLOC_FAILED );
2074
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002075 verif = mbedtls_calloc( 1, ctx->len );
Jens Wiklander817466c2018-05-22 13:49:31 +02002076 if( verif == NULL )
2077 {
2078 mbedtls_free( sig_try );
2079 return( MBEDTLS_ERR_MPI_ALLOC_FAILED );
2080 }
2081
2082 MBEDTLS_MPI_CHK( mbedtls_rsa_private( ctx, f_rng, p_rng, sig, sig_try ) );
2083 MBEDTLS_MPI_CHK( mbedtls_rsa_public( ctx, sig_try, verif ) );
2084
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002085 if( mbedtls_safer_memcmp( verif, sig, ctx->len ) != 0 )
Jens Wiklander817466c2018-05-22 13:49:31 +02002086 {
2087 ret = MBEDTLS_ERR_RSA_PRIVATE_FAILED;
2088 goto cleanup;
2089 }
2090
2091 memcpy( sig, sig_try, ctx->len );
2092
2093cleanup:
2094 mbedtls_free( sig_try );
2095 mbedtls_free( verif );
2096
2097 return( ret );
2098}
2099#endif /* MBEDTLS_PKCS1_V15 */
2100
2101/*
2102 * Do an RSA operation to sign the message digest
2103 */
2104int mbedtls_rsa_pkcs1_sign( mbedtls_rsa_context *ctx,
2105 int (*f_rng)(void *, unsigned char *, size_t),
2106 void *p_rng,
2107 int mode,
2108 mbedtls_md_type_t md_alg,
2109 unsigned int hashlen,
2110 const unsigned char *hash,
2111 unsigned char *sig )
2112{
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002113 RSA_VALIDATE_RET( ctx != NULL );
2114 RSA_VALIDATE_RET( mode == MBEDTLS_RSA_PRIVATE ||
2115 mode == MBEDTLS_RSA_PUBLIC );
2116 RSA_VALIDATE_RET( ( md_alg == MBEDTLS_MD_NONE &&
2117 hashlen == 0 ) ||
2118 hash != NULL );
2119 RSA_VALIDATE_RET( sig != NULL );
2120
Jens Wiklander817466c2018-05-22 13:49:31 +02002121 switch( ctx->padding )
2122 {
2123#if defined(MBEDTLS_PKCS1_V15)
2124 case MBEDTLS_RSA_PKCS_V15:
2125 return mbedtls_rsa_rsassa_pkcs1_v15_sign( ctx, f_rng, p_rng, mode, md_alg,
2126 hashlen, hash, sig );
2127#endif
2128
2129#if defined(MBEDTLS_PKCS1_V21)
2130 case MBEDTLS_RSA_PKCS_V21:
2131 return mbedtls_rsa_rsassa_pss_sign( ctx, f_rng, p_rng, mode, md_alg,
2132 hashlen, hash, sig );
2133#endif
2134
2135 default:
2136 return( MBEDTLS_ERR_RSA_INVALID_PADDING );
2137 }
2138}
2139
2140#if defined(MBEDTLS_PKCS1_V21)
2141/*
2142 * Implementation of the PKCS#1 v2.1 RSASSA-PSS-VERIFY function
2143 */
2144int mbedtls_rsa_rsassa_pss_verify_ext( mbedtls_rsa_context *ctx,
2145 int (*f_rng)(void *, unsigned char *, size_t),
2146 void *p_rng,
2147 int mode,
2148 mbedtls_md_type_t md_alg,
2149 unsigned int hashlen,
2150 const unsigned char *hash,
2151 mbedtls_md_type_t mgf1_hash_id,
2152 int expected_salt_len,
2153 const unsigned char *sig )
2154{
2155 int ret;
2156 size_t siglen;
2157 unsigned char *p;
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002158 unsigned char *hash_start;
Jens Wiklander817466c2018-05-22 13:49:31 +02002159 unsigned char result[MBEDTLS_MD_MAX_SIZE];
2160 unsigned char zeros[8];
2161 unsigned int hlen;
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002162 size_t observed_salt_len, msb;
Jens Wiklander817466c2018-05-22 13:49:31 +02002163 const mbedtls_md_info_t *md_info;
2164 mbedtls_md_context_t md_ctx;
2165 unsigned char buf[MBEDTLS_MPI_MAX_SIZE];
2166
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002167 RSA_VALIDATE_RET( ctx != NULL );
2168 RSA_VALIDATE_RET( mode == MBEDTLS_RSA_PRIVATE ||
2169 mode == MBEDTLS_RSA_PUBLIC );
2170 RSA_VALIDATE_RET( sig != NULL );
2171 RSA_VALIDATE_RET( ( md_alg == MBEDTLS_MD_NONE &&
2172 hashlen == 0 ) ||
2173 hash != NULL );
2174
Jens Wiklander817466c2018-05-22 13:49:31 +02002175 if( mode == MBEDTLS_RSA_PRIVATE && ctx->padding != MBEDTLS_RSA_PKCS_V21 )
2176 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
2177
2178 siglen = ctx->len;
2179
2180 if( siglen < 16 || siglen > sizeof( buf ) )
2181 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
2182
2183 ret = ( mode == MBEDTLS_RSA_PUBLIC )
2184 ? mbedtls_rsa_public( ctx, sig, buf )
2185 : mbedtls_rsa_private( ctx, f_rng, p_rng, sig, buf );
2186
2187 if( ret != 0 )
2188 return( ret );
2189
2190 p = buf;
2191
2192 if( buf[siglen - 1] != 0xBC )
2193 return( MBEDTLS_ERR_RSA_INVALID_PADDING );
2194
2195 if( md_alg != MBEDTLS_MD_NONE )
2196 {
2197 /* Gather length of hash to sign */
2198 md_info = mbedtls_md_info_from_type( md_alg );
2199 if( md_info == NULL )
2200 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
2201
2202 hashlen = mbedtls_md_get_size( md_info );
2203 }
2204
2205 md_info = mbedtls_md_info_from_type( mgf1_hash_id );
2206 if( md_info == NULL )
2207 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
2208
2209 hlen = mbedtls_md_get_size( md_info );
Jens Wiklander817466c2018-05-22 13:49:31 +02002210
2211 memset( zeros, 0, 8 );
2212
2213 /*
2214 * Note: EMSA-PSS verification is over the length of N - 1 bits
2215 */
2216 msb = mbedtls_mpi_bitlen( &ctx->N ) - 1;
2217
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002218 if( buf[0] >> ( 8 - siglen * 8 + msb ) )
2219 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
2220
Jens Wiklander817466c2018-05-22 13:49:31 +02002221 /* Compensate for boundary condition when applying mask */
2222 if( msb % 8 == 0 )
2223 {
2224 p++;
2225 siglen -= 1;
2226 }
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002227
2228 if( siglen < hlen + 2 )
Jens Wiklander817466c2018-05-22 13:49:31 +02002229 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002230 hash_start = p + siglen - hlen - 1;
Jens Wiklander817466c2018-05-22 13:49:31 +02002231
2232 mbedtls_md_init( &md_ctx );
2233 if( ( ret = mbedtls_md_setup( &md_ctx, md_info, 0 ) ) != 0 )
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002234 goto exit;
Jens Wiklander817466c2018-05-22 13:49:31 +02002235
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002236 ret = mgf_mask( p, siglen - hlen - 1, hash_start, hlen, &md_ctx );
2237 if( ret != 0 )
2238 goto exit;
Jens Wiklander817466c2018-05-22 13:49:31 +02002239
2240 buf[0] &= 0xFF >> ( siglen * 8 - msb );
2241
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002242 while( p < hash_start - 1 && *p == 0 )
Jens Wiklander817466c2018-05-22 13:49:31 +02002243 p++;
2244
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002245 if( *p++ != 0x01 )
Jens Wiklander817466c2018-05-22 13:49:31 +02002246 {
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002247 ret = MBEDTLS_ERR_RSA_INVALID_PADDING;
2248 goto exit;
Jens Wiklander817466c2018-05-22 13:49:31 +02002249 }
2250
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002251 observed_salt_len = hash_start - p;
Jens Wiklander817466c2018-05-22 13:49:31 +02002252
2253 if( expected_salt_len != MBEDTLS_RSA_SALT_LEN_ANY &&
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002254 observed_salt_len != (size_t) expected_salt_len )
Jens Wiklander817466c2018-05-22 13:49:31 +02002255 {
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002256 ret = MBEDTLS_ERR_RSA_INVALID_PADDING;
2257 goto exit;
Jens Wiklander817466c2018-05-22 13:49:31 +02002258 }
2259
2260 /*
2261 * Generate H = Hash( M' )
2262 */
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002263 ret = mbedtls_md_starts( &md_ctx );
2264 if ( ret != 0 )
2265 goto exit;
2266 ret = mbedtls_md_update( &md_ctx, zeros, 8 );
2267 if ( ret != 0 )
2268 goto exit;
2269 ret = mbedtls_md_update( &md_ctx, hash, hashlen );
2270 if ( ret != 0 )
2271 goto exit;
2272 ret = mbedtls_md_update( &md_ctx, p, observed_salt_len );
2273 if ( ret != 0 )
2274 goto exit;
2275 ret = mbedtls_md_finish( &md_ctx, result );
2276 if ( ret != 0 )
2277 goto exit;
Jens Wiklander817466c2018-05-22 13:49:31 +02002278
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002279 if( memcmp( hash_start, result, hlen ) != 0 )
2280 {
2281 ret = MBEDTLS_ERR_RSA_VERIFY_FAILED;
2282 goto exit;
2283 }
2284
2285exit:
Jens Wiklander817466c2018-05-22 13:49:31 +02002286 mbedtls_md_free( &md_ctx );
2287
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002288 return( ret );
Jens Wiklander817466c2018-05-22 13:49:31 +02002289}
2290
2291/*
2292 * Simplified PKCS#1 v2.1 RSASSA-PSS-VERIFY function
2293 */
2294int mbedtls_rsa_rsassa_pss_verify( mbedtls_rsa_context *ctx,
2295 int (*f_rng)(void *, unsigned char *, size_t),
2296 void *p_rng,
2297 int mode,
2298 mbedtls_md_type_t md_alg,
2299 unsigned int hashlen,
2300 const unsigned char *hash,
2301 const unsigned char *sig )
2302{
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002303 mbedtls_md_type_t mgf1_hash_id;
2304 RSA_VALIDATE_RET( ctx != NULL );
2305 RSA_VALIDATE_RET( mode == MBEDTLS_RSA_PRIVATE ||
2306 mode == MBEDTLS_RSA_PUBLIC );
2307 RSA_VALIDATE_RET( sig != NULL );
2308 RSA_VALIDATE_RET( ( md_alg == MBEDTLS_MD_NONE &&
2309 hashlen == 0 ) ||
2310 hash != NULL );
2311
2312 mgf1_hash_id = ( ctx->hash_id != MBEDTLS_MD_NONE )
Jens Wiklander817466c2018-05-22 13:49:31 +02002313 ? (mbedtls_md_type_t) ctx->hash_id
2314 : md_alg;
2315
2316 return( mbedtls_rsa_rsassa_pss_verify_ext( ctx, f_rng, p_rng, mode,
2317 md_alg, hashlen, hash,
2318 mgf1_hash_id, MBEDTLS_RSA_SALT_LEN_ANY,
2319 sig ) );
2320
2321}
2322#endif /* MBEDTLS_PKCS1_V21 */
2323
2324#if defined(MBEDTLS_PKCS1_V15)
2325/*
2326 * Implementation of the PKCS#1 v2.1 RSASSA-PKCS1-v1_5-VERIFY function
2327 */
2328int mbedtls_rsa_rsassa_pkcs1_v15_verify( mbedtls_rsa_context *ctx,
2329 int (*f_rng)(void *, unsigned char *, size_t),
2330 void *p_rng,
2331 int mode,
2332 mbedtls_md_type_t md_alg,
2333 unsigned int hashlen,
2334 const unsigned char *hash,
2335 const unsigned char *sig )
2336{
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002337 int ret = 0;
2338 size_t sig_len;
2339 unsigned char *encoded = NULL, *encoded_expected = NULL;
2340
2341 RSA_VALIDATE_RET( ctx != NULL );
2342 RSA_VALIDATE_RET( mode == MBEDTLS_RSA_PRIVATE ||
2343 mode == MBEDTLS_RSA_PUBLIC );
2344 RSA_VALIDATE_RET( sig != NULL );
2345 RSA_VALIDATE_RET( ( md_alg == MBEDTLS_MD_NONE &&
2346 hashlen == 0 ) ||
2347 hash != NULL );
2348
2349 sig_len = ctx->len;
Jens Wiklander817466c2018-05-22 13:49:31 +02002350
2351 if( mode == MBEDTLS_RSA_PRIVATE && ctx->padding != MBEDTLS_RSA_PKCS_V15 )
2352 return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
2353
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002354 /*
2355 * Prepare expected PKCS1 v1.5 encoding of hash.
2356 */
Jens Wiklander817466c2018-05-22 13:49:31 +02002357
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002358 if( ( encoded = mbedtls_calloc( 1, sig_len ) ) == NULL ||
2359 ( encoded_expected = mbedtls_calloc( 1, sig_len ) ) == NULL )
2360 {
2361 ret = MBEDTLS_ERR_MPI_ALLOC_FAILED;
2362 goto cleanup;
2363 }
2364
2365 if( ( ret = rsa_rsassa_pkcs1_v15_encode( md_alg, hashlen, hash, sig_len,
2366 encoded_expected ) ) != 0 )
2367 goto cleanup;
2368
2369 /*
2370 * Apply RSA primitive to get what should be PKCS1 encoded hash.
2371 */
Jens Wiklander817466c2018-05-22 13:49:31 +02002372
2373 ret = ( mode == MBEDTLS_RSA_PUBLIC )
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002374 ? mbedtls_rsa_public( ctx, sig, encoded )
2375 : mbedtls_rsa_private( ctx, f_rng, p_rng, sig, encoded );
Jens Wiklander817466c2018-05-22 13:49:31 +02002376 if( ret != 0 )
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002377 goto cleanup;
Jens Wiklander817466c2018-05-22 13:49:31 +02002378
2379 /*
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002380 * Compare
Jens Wiklander817466c2018-05-22 13:49:31 +02002381 */
Jens Wiklander817466c2018-05-22 13:49:31 +02002382
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002383 if( ( ret = mbedtls_safer_memcmp( encoded, encoded_expected,
2384 sig_len ) ) != 0 )
2385 {
2386 ret = MBEDTLS_ERR_RSA_VERIFY_FAILED;
2387 goto cleanup;
2388 }
Jens Wiklander817466c2018-05-22 13:49:31 +02002389
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002390cleanup:
Jens Wiklander817466c2018-05-22 13:49:31 +02002391
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002392 if( encoded != NULL )
2393 {
2394 mbedtls_platform_zeroize( encoded, sig_len );
2395 mbedtls_free( encoded );
2396 }
Jens Wiklander817466c2018-05-22 13:49:31 +02002397
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002398 if( encoded_expected != NULL )
2399 {
2400 mbedtls_platform_zeroize( encoded_expected, sig_len );
2401 mbedtls_free( encoded_expected );
2402 }
Jens Wiklander817466c2018-05-22 13:49:31 +02002403
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002404 return( ret );
Jens Wiklander817466c2018-05-22 13:49:31 +02002405}
2406#endif /* MBEDTLS_PKCS1_V15 */
2407
2408/*
2409 * Do an RSA operation and check the message digest
2410 */
2411int mbedtls_rsa_pkcs1_verify( mbedtls_rsa_context *ctx,
2412 int (*f_rng)(void *, unsigned char *, size_t),
2413 void *p_rng,
2414 int mode,
2415 mbedtls_md_type_t md_alg,
2416 unsigned int hashlen,
2417 const unsigned char *hash,
2418 const unsigned char *sig )
2419{
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002420 RSA_VALIDATE_RET( ctx != NULL );
2421 RSA_VALIDATE_RET( mode == MBEDTLS_RSA_PRIVATE ||
2422 mode == MBEDTLS_RSA_PUBLIC );
2423 RSA_VALIDATE_RET( sig != NULL );
2424 RSA_VALIDATE_RET( ( md_alg == MBEDTLS_MD_NONE &&
2425 hashlen == 0 ) ||
2426 hash != NULL );
2427
Jens Wiklander817466c2018-05-22 13:49:31 +02002428 switch( ctx->padding )
2429 {
2430#if defined(MBEDTLS_PKCS1_V15)
2431 case MBEDTLS_RSA_PKCS_V15:
2432 return mbedtls_rsa_rsassa_pkcs1_v15_verify( ctx, f_rng, p_rng, mode, md_alg,
2433 hashlen, hash, sig );
2434#endif
2435
2436#if defined(MBEDTLS_PKCS1_V21)
2437 case MBEDTLS_RSA_PKCS_V21:
2438 return mbedtls_rsa_rsassa_pss_verify( ctx, f_rng, p_rng, mode, md_alg,
2439 hashlen, hash, sig );
2440#endif
2441
2442 default:
2443 return( MBEDTLS_ERR_RSA_INVALID_PADDING );
2444 }
2445}
2446
2447/*
2448 * Copy the components of an RSA key
2449 */
2450int mbedtls_rsa_copy( mbedtls_rsa_context *dst, const mbedtls_rsa_context *src )
2451{
2452 int ret;
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002453 RSA_VALIDATE_RET( dst != NULL );
2454 RSA_VALIDATE_RET( src != NULL );
Jens Wiklander817466c2018-05-22 13:49:31 +02002455
2456 dst->ver = src->ver;
2457 dst->len = src->len;
2458
2459 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &dst->N, &src->N ) );
2460 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &dst->E, &src->E ) );
2461
2462 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &dst->D, &src->D ) );
2463 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &dst->P, &src->P ) );
2464 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &dst->Q, &src->Q ) );
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002465
2466#if !defined(MBEDTLS_RSA_NO_CRT)
Jens Wiklander817466c2018-05-22 13:49:31 +02002467 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &dst->DP, &src->DP ) );
2468 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &dst->DQ, &src->DQ ) );
2469 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &dst->QP, &src->QP ) );
Jens Wiklander817466c2018-05-22 13:49:31 +02002470 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &dst->RP, &src->RP ) );
2471 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &dst->RQ, &src->RQ ) );
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002472#endif
2473
2474 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &dst->RN, &src->RN ) );
Jens Wiklander817466c2018-05-22 13:49:31 +02002475
2476 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &dst->Vi, &src->Vi ) );
2477 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &dst->Vf, &src->Vf ) );
2478
2479 dst->padding = src->padding;
2480 dst->hash_id = src->hash_id;
2481
2482cleanup:
2483 if( ret != 0 )
2484 mbedtls_rsa_free( dst );
2485
2486 return( ret );
2487}
2488
2489/*
2490 * Free the components of an RSA key
2491 */
2492void mbedtls_rsa_free( mbedtls_rsa_context *ctx )
2493{
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002494 if( ctx == NULL )
2495 return;
2496
2497 mbedtls_mpi_free( &ctx->Vi );
2498 mbedtls_mpi_free( &ctx->Vf );
2499 mbedtls_mpi_free( &ctx->RN );
2500 mbedtls_mpi_free( &ctx->D );
2501 mbedtls_mpi_free( &ctx->Q );
2502 mbedtls_mpi_free( &ctx->P );
2503 mbedtls_mpi_free( &ctx->E );
2504 mbedtls_mpi_free( &ctx->N );
2505
2506#if !defined(MBEDTLS_RSA_NO_CRT)
2507 mbedtls_mpi_free( &ctx->RQ );
2508 mbedtls_mpi_free( &ctx->RP );
2509 mbedtls_mpi_free( &ctx->QP );
2510 mbedtls_mpi_free( &ctx->DQ );
2511 mbedtls_mpi_free( &ctx->DP );
2512#endif /* MBEDTLS_RSA_NO_CRT */
Jens Wiklander817466c2018-05-22 13:49:31 +02002513
2514#if defined(MBEDTLS_THREADING_C)
2515 mbedtls_mutex_free( &ctx->mutex );
2516#endif
2517}
2518
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002519#endif /* !MBEDTLS_RSA_ALT */
2520
Jens Wiklander817466c2018-05-22 13:49:31 +02002521#if defined(MBEDTLS_SELF_TEST)
2522
2523#include "mbedtls/sha1.h"
2524
2525/*
2526 * Example RSA-1024 keypair, for test purposes
2527 */
2528#define KEY_LEN 128
2529
2530#define RSA_N "9292758453063D803DD603D5E777D788" \
2531 "8ED1D5BF35786190FA2F23EBC0848AEA" \
2532 "DDA92CA6C3D80B32C4D109BE0F36D6AE" \
2533 "7130B9CED7ACDF54CFC7555AC14EEBAB" \
2534 "93A89813FBF3C4F8066D2D800F7C38A8" \
2535 "1AE31942917403FF4946B0A83D3D3E05" \
2536 "EE57C6F5F5606FB5D4BC6CD34EE0801A" \
2537 "5E94BB77B07507233A0BC7BAC8F90F79"
2538
2539#define RSA_E "10001"
2540
2541#define RSA_D "24BF6185468786FDD303083D25E64EFC" \
2542 "66CA472BC44D253102F8B4A9D3BFA750" \
2543 "91386C0077937FE33FA3252D28855837" \
2544 "AE1B484A8A9A45F7EE8C0C634F99E8CD" \
2545 "DF79C5CE07EE72C7F123142198164234" \
2546 "CABB724CF78B8173B9F880FC86322407" \
2547 "AF1FEDFDDE2BEB674CA15F3E81A1521E" \
2548 "071513A1E85B5DFA031F21ECAE91A34D"
2549
2550#define RSA_P "C36D0EB7FCD285223CFB5AABA5BDA3D8" \
2551 "2C01CAD19EA484A87EA4377637E75500" \
2552 "FCB2005C5C7DD6EC4AC023CDA285D796" \
2553 "C3D9E75E1EFC42488BB4F1D13AC30A57"
2554
2555#define RSA_Q "C000DF51A7C77AE8D7C7370C1FF55B69" \
2556 "E211C2B9E5DB1ED0BF61D0D9899620F4" \
2557 "910E4168387E3C30AA1E00C339A79508" \
2558 "8452DD96A9A5EA5D9DCA68DA636032AF"
2559
Jens Wiklander817466c2018-05-22 13:49:31 +02002560#define PT_LEN 24
2561#define RSA_PT "\xAA\xBB\xCC\x03\x02\x01\x00\xFF\xFF\xFF\xFF\xFF" \
2562 "\x11\x22\x33\x0A\x0B\x0C\xCC\xDD\xDD\xDD\xDD\xDD"
2563
2564#if defined(MBEDTLS_PKCS1_V15)
2565static int myrand( void *rng_state, unsigned char *output, size_t len )
2566{
2567#if !defined(__OpenBSD__)
2568 size_t i;
2569
2570 if( rng_state != NULL )
2571 rng_state = NULL;
2572
2573 for( i = 0; i < len; ++i )
2574 output[i] = rand();
2575#else
2576 if( rng_state != NULL )
2577 rng_state = NULL;
2578
2579 arc4random_buf( output, len );
2580#endif /* !OpenBSD */
2581
2582 return( 0 );
2583}
2584#endif /* MBEDTLS_PKCS1_V15 */
2585
2586/*
2587 * Checkup routine
2588 */
2589int mbedtls_rsa_self_test( int verbose )
2590{
2591 int ret = 0;
2592#if defined(MBEDTLS_PKCS1_V15)
2593 size_t len;
2594 mbedtls_rsa_context rsa;
2595 unsigned char rsa_plaintext[PT_LEN];
2596 unsigned char rsa_decrypted[PT_LEN];
2597 unsigned char rsa_ciphertext[KEY_LEN];
2598#if defined(MBEDTLS_SHA1_C)
2599 unsigned char sha1sum[20];
2600#endif
2601
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002602 mbedtls_mpi K;
2603
2604 mbedtls_mpi_init( &K );
Jens Wiklander817466c2018-05-22 13:49:31 +02002605 mbedtls_rsa_init( &rsa, MBEDTLS_RSA_PKCS_V15, 0 );
2606
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002607 MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( &K, 16, RSA_N ) );
2608 MBEDTLS_MPI_CHK( mbedtls_rsa_import( &rsa, &K, NULL, NULL, NULL, NULL ) );
2609 MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( &K, 16, RSA_P ) );
2610 MBEDTLS_MPI_CHK( mbedtls_rsa_import( &rsa, NULL, &K, NULL, NULL, NULL ) );
2611 MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( &K, 16, RSA_Q ) );
2612 MBEDTLS_MPI_CHK( mbedtls_rsa_import( &rsa, NULL, NULL, &K, NULL, NULL ) );
2613 MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( &K, 16, RSA_D ) );
2614 MBEDTLS_MPI_CHK( mbedtls_rsa_import( &rsa, NULL, NULL, NULL, &K, NULL ) );
2615 MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( &K, 16, RSA_E ) );
2616 MBEDTLS_MPI_CHK( mbedtls_rsa_import( &rsa, NULL, NULL, NULL, NULL, &K ) );
2617
2618 MBEDTLS_MPI_CHK( mbedtls_rsa_complete( &rsa ) );
Jens Wiklander817466c2018-05-22 13:49:31 +02002619
2620 if( verbose != 0 )
2621 mbedtls_printf( " RSA key validation: " );
2622
2623 if( mbedtls_rsa_check_pubkey( &rsa ) != 0 ||
2624 mbedtls_rsa_check_privkey( &rsa ) != 0 )
2625 {
2626 if( verbose != 0 )
2627 mbedtls_printf( "failed\n" );
2628
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002629 ret = 1;
2630 goto cleanup;
Jens Wiklander817466c2018-05-22 13:49:31 +02002631 }
2632
2633 if( verbose != 0 )
2634 mbedtls_printf( "passed\n PKCS#1 encryption : " );
2635
2636 memcpy( rsa_plaintext, RSA_PT, PT_LEN );
2637
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002638 if( mbedtls_rsa_pkcs1_encrypt( &rsa, myrand, NULL, MBEDTLS_RSA_PUBLIC,
2639 PT_LEN, rsa_plaintext,
2640 rsa_ciphertext ) != 0 )
Jens Wiklander817466c2018-05-22 13:49:31 +02002641 {
2642 if( verbose != 0 )
2643 mbedtls_printf( "failed\n" );
2644
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002645 ret = 1;
2646 goto cleanup;
Jens Wiklander817466c2018-05-22 13:49:31 +02002647 }
2648
2649 if( verbose != 0 )
2650 mbedtls_printf( "passed\n PKCS#1 decryption : " );
2651
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002652 if( mbedtls_rsa_pkcs1_decrypt( &rsa, myrand, NULL, MBEDTLS_RSA_PRIVATE,
2653 &len, rsa_ciphertext, rsa_decrypted,
2654 sizeof(rsa_decrypted) ) != 0 )
Jens Wiklander817466c2018-05-22 13:49:31 +02002655 {
2656 if( verbose != 0 )
2657 mbedtls_printf( "failed\n" );
2658
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002659 ret = 1;
2660 goto cleanup;
Jens Wiklander817466c2018-05-22 13:49:31 +02002661 }
2662
2663 if( memcmp( rsa_decrypted, rsa_plaintext, len ) != 0 )
2664 {
2665 if( verbose != 0 )
2666 mbedtls_printf( "failed\n" );
2667
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002668 ret = 1;
2669 goto cleanup;
Jens Wiklander817466c2018-05-22 13:49:31 +02002670 }
2671
2672 if( verbose != 0 )
2673 mbedtls_printf( "passed\n" );
2674
2675#if defined(MBEDTLS_SHA1_C)
2676 if( verbose != 0 )
2677 mbedtls_printf( " PKCS#1 data sign : " );
2678
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002679 if( mbedtls_sha1_ret( rsa_plaintext, PT_LEN, sha1sum ) != 0 )
Jens Wiklander817466c2018-05-22 13:49:31 +02002680 {
2681 if( verbose != 0 )
2682 mbedtls_printf( "failed\n" );
2683
2684 return( 1 );
2685 }
2686
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002687 if( mbedtls_rsa_pkcs1_sign( &rsa, myrand, NULL,
2688 MBEDTLS_RSA_PRIVATE, MBEDTLS_MD_SHA1, 0,
2689 sha1sum, rsa_ciphertext ) != 0 )
Jens Wiklander817466c2018-05-22 13:49:31 +02002690 {
2691 if( verbose != 0 )
2692 mbedtls_printf( "failed\n" );
2693
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002694 ret = 1;
2695 goto cleanup;
2696 }
2697
2698 if( verbose != 0 )
2699 mbedtls_printf( "passed\n PKCS#1 sig. verify: " );
2700
2701 if( mbedtls_rsa_pkcs1_verify( &rsa, NULL, NULL,
2702 MBEDTLS_RSA_PUBLIC, MBEDTLS_MD_SHA1, 0,
2703 sha1sum, rsa_ciphertext ) != 0 )
2704 {
2705 if( verbose != 0 )
2706 mbedtls_printf( "failed\n" );
2707
2708 ret = 1;
2709 goto cleanup;
Jens Wiklander817466c2018-05-22 13:49:31 +02002710 }
2711
2712 if( verbose != 0 )
2713 mbedtls_printf( "passed\n" );
2714#endif /* MBEDTLS_SHA1_C */
2715
2716 if( verbose != 0 )
2717 mbedtls_printf( "\n" );
2718
2719cleanup:
Jens Wiklander50a57cf2019-03-13 10:41:54 +01002720 mbedtls_mpi_free( &K );
Jens Wiklander817466c2018-05-22 13:49:31 +02002721 mbedtls_rsa_free( &rsa );
2722#else /* MBEDTLS_PKCS1_V15 */
2723 ((void) verbose);
2724#endif /* MBEDTLS_PKCS1_V15 */
2725 return( ret );
2726}
2727
2728#endif /* MBEDTLS_SELF_TEST */
2729
2730#endif /* MBEDTLS_RSA_C */