Line data Source code
1 : /*
2 : * The RSA public-key cryptosystem
3 : *
4 : * Copyright The Mbed TLS Contributors
5 : * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
6 : */
7 :
8 : /*
9 : * The following sources were referenced in the design of this implementation
10 : * of the RSA algorithm:
11 : *
12 : * [1] A method for obtaining digital signatures and public-key cryptosystems
13 : * R Rivest, A Shamir, and L Adleman
14 : * http://people.csail.mit.edu/rivest/pubs.html#RSA78
15 : *
16 : * [2] Handbook of Applied Cryptography - 1997, Chapter 8
17 : * Menezes, van Oorschot and Vanstone
18 : *
19 : * [3] Malware Guard Extension: Using SGX to Conceal Cache Attacks
20 : * Michael Schwarz, Samuel Weiser, Daniel Gruss, Clémentine Maurice and
21 : * Stefan Mangard
22 : * https://arxiv.org/abs/1702.08719v2
23 : *
24 : */
25 :
26 : #include "common.h"
27 :
28 : #if defined(MBEDTLS_RSA_C)
29 :
30 : #include "mbedtls/rsa.h"
31 : #include "bignum_core.h"
32 : #include "bignum_internal.h"
33 : #include "rsa_alt_helpers.h"
34 : #include "rsa_internal.h"
35 : #include "mbedtls/oid.h"
36 : #include "mbedtls/asn1write.h"
37 : #include "mbedtls/platform_util.h"
38 : #include "mbedtls/error.h"
39 : #include "constant_time_internal.h"
40 : #include "mbedtls/constant_time.h"
41 : #include "md_psa.h"
42 :
43 : #include <string.h>
44 :
45 : #if defined(MBEDTLS_PKCS1_V15) && !defined(__OpenBSD__) && !defined(__NetBSD__)
46 : #include <stdlib.h>
47 : #endif
48 :
49 : #include "mbedtls/platform.h"
50 :
51 : /*
52 : * Wrapper around mbedtls_asn1_get_mpi() that rejects zero.
53 : *
54 : * The value zero is:
55 : * - never a valid value for an RSA parameter
56 : * - interpreted as "omitted, please reconstruct" by mbedtls_rsa_complete().
57 : *
58 : * Since values can't be omitted in PKCS#1, passing a zero value to
59 : * rsa_complete() would be incorrect, so reject zero values early.
60 : */
61 288 : static int asn1_get_nonzero_mpi(unsigned char **p,
62 : const unsigned char *end,
63 : mbedtls_mpi *X)
64 : {
65 : int ret;
66 :
67 288 : ret = mbedtls_asn1_get_mpi(p, end, X);
68 288 : if (ret != 0) {
69 0 : return ret;
70 : }
71 :
72 288 : if (mbedtls_mpi_cmp_int(X, 0) == 0) {
73 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
74 : }
75 :
76 288 : return 0;
77 : }
78 :
79 36 : int mbedtls_rsa_parse_key(mbedtls_rsa_context *rsa, const unsigned char *key, size_t keylen)
80 : {
81 : int ret, version;
82 : size_t len;
83 : unsigned char *p, *end;
84 :
85 : mbedtls_mpi T;
86 36 : mbedtls_mpi_init(&T);
87 :
88 36 : p = (unsigned char *) key;
89 36 : end = p + keylen;
90 :
91 : /*
92 : * This function parses the RSAPrivateKey (PKCS#1)
93 : *
94 : * RSAPrivateKey ::= SEQUENCE {
95 : * version Version,
96 : * modulus INTEGER, -- n
97 : * publicExponent INTEGER, -- e
98 : * privateExponent INTEGER, -- d
99 : * prime1 INTEGER, -- p
100 : * prime2 INTEGER, -- q
101 : * exponent1 INTEGER, -- d mod (p-1)
102 : * exponent2 INTEGER, -- d mod (q-1)
103 : * coefficient INTEGER, -- (inverse of q) mod p
104 : * otherPrimeInfos OtherPrimeInfos OPTIONAL
105 : * }
106 : */
107 36 : if ((ret = mbedtls_asn1_get_tag(&p, end, &len,
108 : MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) != 0) {
109 0 : return ret;
110 : }
111 :
112 36 : if (end != p + len) {
113 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
114 : }
115 :
116 36 : if ((ret = mbedtls_asn1_get_int(&p, end, &version)) != 0) {
117 0 : return ret;
118 : }
119 :
120 36 : if (version != 0) {
121 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
122 : }
123 :
124 : /* Import N */
125 72 : if ((ret = asn1_get_nonzero_mpi(&p, end, &T)) != 0 ||
126 36 : (ret = mbedtls_rsa_import(rsa, &T, NULL, NULL,
127 : NULL, NULL)) != 0) {
128 0 : goto cleanup;
129 : }
130 :
131 : /* Import E */
132 72 : if ((ret = asn1_get_nonzero_mpi(&p, end, &T)) != 0 ||
133 36 : (ret = mbedtls_rsa_import(rsa, NULL, NULL, NULL,
134 : NULL, &T)) != 0) {
135 0 : goto cleanup;
136 : }
137 :
138 : /* Import D */
139 72 : if ((ret = asn1_get_nonzero_mpi(&p, end, &T)) != 0 ||
140 36 : (ret = mbedtls_rsa_import(rsa, NULL, NULL, NULL,
141 : &T, NULL)) != 0) {
142 0 : goto cleanup;
143 : }
144 :
145 : /* Import P */
146 72 : if ((ret = asn1_get_nonzero_mpi(&p, end, &T)) != 0 ||
147 36 : (ret = mbedtls_rsa_import(rsa, NULL, &T, NULL,
148 : NULL, NULL)) != 0) {
149 0 : goto cleanup;
150 : }
151 :
152 : /* Import Q */
153 72 : if ((ret = asn1_get_nonzero_mpi(&p, end, &T)) != 0 ||
154 36 : (ret = mbedtls_rsa_import(rsa, NULL, NULL, &T,
155 : NULL, NULL)) != 0) {
156 0 : goto cleanup;
157 : }
158 :
159 : #if !defined(MBEDTLS_RSA_NO_CRT) && !defined(MBEDTLS_RSA_ALT)
160 : /*
161 : * The RSA CRT parameters DP, DQ and QP are nominally redundant, in
162 : * that they can be easily recomputed from D, P and Q. However by
163 : * parsing them from the PKCS1 structure it is possible to avoid
164 : * recalculating them which both reduces the overhead of loading
165 : * RSA private keys into memory and also avoids side channels which
166 : * can arise when computing those values, since all of D, P, and Q
167 : * are secret. See https://eprint.iacr.org/2020/055 for a
168 : * description of one such attack.
169 : */
170 :
171 : /* Import DP */
172 72 : if ((ret = asn1_get_nonzero_mpi(&p, end, &T)) != 0 ||
173 36 : (ret = mbedtls_mpi_copy(&rsa->DP, &T)) != 0) {
174 0 : goto cleanup;
175 : }
176 :
177 : /* Import DQ */
178 72 : if ((ret = asn1_get_nonzero_mpi(&p, end, &T)) != 0 ||
179 36 : (ret = mbedtls_mpi_copy(&rsa->DQ, &T)) != 0) {
180 0 : goto cleanup;
181 : }
182 :
183 : /* Import QP */
184 72 : if ((ret = asn1_get_nonzero_mpi(&p, end, &T)) != 0 ||
185 36 : (ret = mbedtls_mpi_copy(&rsa->QP, &T)) != 0) {
186 0 : goto cleanup;
187 : }
188 :
189 : #else
190 : /* Verify existence of the CRT params */
191 : if ((ret = asn1_get_nonzero_mpi(&p, end, &T)) != 0 ||
192 : (ret = asn1_get_nonzero_mpi(&p, end, &T)) != 0 ||
193 : (ret = asn1_get_nonzero_mpi(&p, end, &T)) != 0) {
194 : goto cleanup;
195 : }
196 : #endif
197 :
198 : /* rsa_complete() doesn't complete anything with the default
199 : * implementation but is still called:
200 : * - for the benefit of alternative implementation that may want to
201 : * pre-compute stuff beyond what's provided (eg Montgomery factors)
202 : * - as is also sanity-checks the key
203 : *
204 : * Furthermore, we also check the public part for consistency with
205 : * mbedtls_pk_parse_pubkey(), as it includes size minima for example.
206 : */
207 72 : if ((ret = mbedtls_rsa_complete(rsa)) != 0 ||
208 36 : (ret = mbedtls_rsa_check_pubkey(rsa)) != 0) {
209 0 : goto cleanup;
210 : }
211 :
212 36 : if (p != end) {
213 0 : ret = MBEDTLS_ERR_ASN1_LENGTH_MISMATCH;
214 : }
215 :
216 36 : cleanup:
217 :
218 36 : mbedtls_mpi_free(&T);
219 :
220 36 : if (ret != 0) {
221 0 : mbedtls_rsa_free(rsa);
222 : }
223 :
224 36 : return ret;
225 : }
226 :
227 1325 : int mbedtls_rsa_parse_pubkey(mbedtls_rsa_context *rsa, const unsigned char *key, size_t keylen)
228 : {
229 1325 : unsigned char *p = (unsigned char *) key;
230 1325 : unsigned char *end = (unsigned char *) (key + keylen);
231 1325 : int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
232 : size_t len;
233 :
234 : /*
235 : * RSAPublicKey ::= SEQUENCE {
236 : * modulus INTEGER, -- n
237 : * publicExponent INTEGER -- e
238 : * }
239 : */
240 :
241 1325 : if ((ret = mbedtls_asn1_get_tag(&p, end, &len,
242 : MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) != 0) {
243 0 : return ret;
244 : }
245 :
246 1325 : if (end != p + len) {
247 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
248 : }
249 :
250 : /* Import N */
251 1325 : if ((ret = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_INTEGER)) != 0) {
252 10 : return ret;
253 : }
254 :
255 1315 : if ((ret = mbedtls_rsa_import_raw(rsa, p, len, NULL, 0, NULL, 0,
256 : NULL, 0, NULL, 0)) != 0) {
257 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
258 : }
259 :
260 1315 : p += len;
261 :
262 : /* Import E */
263 1315 : if ((ret = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_INTEGER)) != 0) {
264 0 : return ret;
265 : }
266 :
267 1315 : if ((ret = mbedtls_rsa_import_raw(rsa, NULL, 0, NULL, 0, NULL, 0,
268 : NULL, 0, p, len)) != 0) {
269 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
270 : }
271 :
272 1315 : p += len;
273 :
274 2630 : if (mbedtls_rsa_complete(rsa) != 0 ||
275 1315 : mbedtls_rsa_check_pubkey(rsa) != 0) {
276 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
277 : }
278 :
279 1315 : if (p != end) {
280 0 : return MBEDTLS_ERR_ASN1_LENGTH_MISMATCH;
281 : }
282 :
283 1315 : return 0;
284 : }
285 :
286 0 : int mbedtls_rsa_write_key(const mbedtls_rsa_context *rsa, unsigned char *start,
287 : unsigned char **p)
288 : {
289 0 : size_t len = 0;
290 : int ret;
291 :
292 : mbedtls_mpi T; /* Temporary holding the exported parameters */
293 :
294 : /*
295 : * Export the parameters one after another to avoid simultaneous copies.
296 : */
297 :
298 0 : mbedtls_mpi_init(&T);
299 :
300 : /* Export QP */
301 0 : if ((ret = mbedtls_rsa_export_crt(rsa, NULL, NULL, &T)) != 0 ||
302 0 : (ret = mbedtls_asn1_write_mpi(p, start, &T)) < 0) {
303 0 : goto end_of_export;
304 : }
305 0 : len += ret;
306 :
307 : /* Export DQ */
308 0 : if ((ret = mbedtls_rsa_export_crt(rsa, NULL, &T, NULL)) != 0 ||
309 0 : (ret = mbedtls_asn1_write_mpi(p, start, &T)) < 0) {
310 0 : goto end_of_export;
311 : }
312 0 : len += ret;
313 :
314 : /* Export DP */
315 0 : if ((ret = mbedtls_rsa_export_crt(rsa, &T, NULL, NULL)) != 0 ||
316 0 : (ret = mbedtls_asn1_write_mpi(p, start, &T)) < 0) {
317 0 : goto end_of_export;
318 : }
319 0 : len += ret;
320 :
321 : /* Export Q */
322 0 : if ((ret = mbedtls_rsa_export(rsa, NULL, NULL, &T, NULL, NULL)) != 0 ||
323 0 : (ret = mbedtls_asn1_write_mpi(p, start, &T)) < 0) {
324 0 : goto end_of_export;
325 : }
326 0 : len += ret;
327 :
328 : /* Export P */
329 0 : if ((ret = mbedtls_rsa_export(rsa, NULL, &T, NULL, NULL, NULL)) != 0 ||
330 0 : (ret = mbedtls_asn1_write_mpi(p, start, &T)) < 0) {
331 0 : goto end_of_export;
332 : }
333 0 : len += ret;
334 :
335 : /* Export D */
336 0 : if ((ret = mbedtls_rsa_export(rsa, NULL, NULL, NULL, &T, NULL)) != 0 ||
337 0 : (ret = mbedtls_asn1_write_mpi(p, start, &T)) < 0) {
338 0 : goto end_of_export;
339 : }
340 0 : len += ret;
341 :
342 : /* Export E */
343 0 : if ((ret = mbedtls_rsa_export(rsa, NULL, NULL, NULL, NULL, &T)) != 0 ||
344 0 : (ret = mbedtls_asn1_write_mpi(p, start, &T)) < 0) {
345 0 : goto end_of_export;
346 : }
347 0 : len += ret;
348 :
349 : /* Export N */
350 0 : if ((ret = mbedtls_rsa_export(rsa, &T, NULL, NULL, NULL, NULL)) != 0 ||
351 0 : (ret = mbedtls_asn1_write_mpi(p, start, &T)) < 0) {
352 0 : goto end_of_export;
353 : }
354 0 : len += ret;
355 :
356 0 : end_of_export:
357 :
358 0 : mbedtls_mpi_free(&T);
359 0 : if (ret < 0) {
360 0 : return ret;
361 : }
362 :
363 0 : MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_int(p, start, 0));
364 0 : MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len));
365 0 : MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start,
366 : MBEDTLS_ASN1_CONSTRUCTED |
367 : MBEDTLS_ASN1_SEQUENCE));
368 :
369 0 : return (int) len;
370 : }
371 :
372 : /*
373 : * RSAPublicKey ::= SEQUENCE {
374 : * modulus INTEGER, -- n
375 : * publicExponent INTEGER -- e
376 : * }
377 : */
378 0 : int mbedtls_rsa_write_pubkey(const mbedtls_rsa_context *rsa, unsigned char *start,
379 : unsigned char **p)
380 : {
381 0 : int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
382 0 : size_t len = 0;
383 : mbedtls_mpi T;
384 :
385 0 : mbedtls_mpi_init(&T);
386 :
387 : /* Export E */
388 0 : if ((ret = mbedtls_rsa_export(rsa, NULL, NULL, NULL, NULL, &T)) != 0 ||
389 0 : (ret = mbedtls_asn1_write_mpi(p, start, &T)) < 0) {
390 0 : goto end_of_export;
391 : }
392 0 : len += ret;
393 :
394 : /* Export N */
395 0 : if ((ret = mbedtls_rsa_export(rsa, &T, NULL, NULL, NULL, NULL)) != 0 ||
396 0 : (ret = mbedtls_asn1_write_mpi(p, start, &T)) < 0) {
397 0 : goto end_of_export;
398 : }
399 0 : len += ret;
400 :
401 0 : end_of_export:
402 :
403 0 : mbedtls_mpi_free(&T);
404 0 : if (ret < 0) {
405 0 : return ret;
406 : }
407 :
408 0 : MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len));
409 0 : MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, MBEDTLS_ASN1_CONSTRUCTED |
410 : MBEDTLS_ASN1_SEQUENCE));
411 :
412 0 : return (int) len;
413 : }
414 :
415 : #if defined(MBEDTLS_PKCS1_V15) && defined(MBEDTLS_RSA_C) && !defined(MBEDTLS_RSA_ALT)
416 :
417 : /** This function performs the unpadding part of a PKCS#1 v1.5 decryption
418 : * operation (EME-PKCS1-v1_5 decoding).
419 : *
420 : * \note The return value from this function is a sensitive value
421 : * (this is unusual). #MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE shouldn't happen
422 : * in a well-written application, but 0 vs #MBEDTLS_ERR_RSA_INVALID_PADDING
423 : * is often a situation that an attacker can provoke and leaking which
424 : * one is the result is precisely the information the attacker wants.
425 : *
426 : * \param input The input buffer which is the payload inside PKCS#1v1.5
427 : * encryption padding, called the "encoded message EM"
428 : * by the terminology.
429 : * \param ilen The length of the payload in the \p input buffer.
430 : * \param output The buffer for the payload, called "message M" by the
431 : * PKCS#1 terminology. This must be a writable buffer of
432 : * length \p output_max_len bytes.
433 : * \param olen The address at which to store the length of
434 : * the payload. This must not be \c NULL.
435 : * \param output_max_len The length in bytes of the output buffer \p output.
436 : *
437 : * \return \c 0 on success.
438 : * \return #MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE
439 : * The output buffer is too small for the unpadded payload.
440 : * \return #MBEDTLS_ERR_RSA_INVALID_PADDING
441 : * The input doesn't contain properly formatted padding.
442 : */
443 0 : static int mbedtls_ct_rsaes_pkcs1_v15_unpadding(unsigned char *input,
444 : size_t ilen,
445 : unsigned char *output,
446 : size_t output_max_len,
447 : size_t *olen)
448 : {
449 0 : int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
450 : size_t i, plaintext_max_size;
451 :
452 : /* The following variables take sensitive values: their value must
453 : * not leak into the observable behavior of the function other than
454 : * the designated outputs (output, olen, return value). Otherwise
455 : * this would open the execution of the function to
456 : * side-channel-based variants of the Bleichenbacher padding oracle
457 : * attack. Potential side channels include overall timing, memory
458 : * access patterns (especially visible to an adversary who has access
459 : * to a shared memory cache), and branches (especially visible to
460 : * an adversary who has access to a shared code cache or to a shared
461 : * branch predictor). */
462 0 : size_t pad_count = 0;
463 : mbedtls_ct_condition_t bad;
464 : mbedtls_ct_condition_t pad_done;
465 0 : size_t plaintext_size = 0;
466 : mbedtls_ct_condition_t output_too_large;
467 :
468 0 : plaintext_max_size = (output_max_len > ilen - 11) ? ilen - 11
469 : : output_max_len;
470 :
471 : /* Check and get padding length in constant time and constant
472 : * memory trace. The first byte must be 0. */
473 0 : bad = mbedtls_ct_bool(input[0]);
474 :
475 :
476 : /* Decode EME-PKCS1-v1_5 padding: 0x00 || 0x02 || PS || 0x00
477 : * where PS must be at least 8 nonzero bytes. */
478 0 : bad = mbedtls_ct_bool_or(bad, mbedtls_ct_uint_ne(input[1], MBEDTLS_RSA_CRYPT));
479 :
480 : /* Read the whole buffer. Set pad_done to nonzero if we find
481 : * the 0x00 byte and remember the padding length in pad_count. */
482 0 : pad_done = MBEDTLS_CT_FALSE;
483 0 : for (i = 2; i < ilen; i++) {
484 0 : mbedtls_ct_condition_t found = mbedtls_ct_uint_eq(input[i], 0);
485 0 : pad_done = mbedtls_ct_bool_or(pad_done, found);
486 0 : pad_count += mbedtls_ct_uint_if_else_0(mbedtls_ct_bool_not(pad_done), 1);
487 : }
488 :
489 : /* If pad_done is still zero, there's no data, only unfinished padding. */
490 0 : bad = mbedtls_ct_bool_or(bad, mbedtls_ct_bool_not(pad_done));
491 :
492 : /* There must be at least 8 bytes of padding. */
493 0 : bad = mbedtls_ct_bool_or(bad, mbedtls_ct_uint_gt(8, pad_count));
494 :
495 : /* If the padding is valid, set plaintext_size to the number of
496 : * remaining bytes after stripping the padding. If the padding
497 : * is invalid, avoid leaking this fact through the size of the
498 : * output: use the maximum message size that fits in the output
499 : * buffer. Do it without branches to avoid leaking the padding
500 : * validity through timing. RSA keys are small enough that all the
501 : * size_t values involved fit in unsigned int. */
502 0 : plaintext_size = mbedtls_ct_uint_if(
503 : bad, (unsigned) plaintext_max_size,
504 0 : (unsigned) (ilen - pad_count - 3));
505 :
506 : /* Set output_too_large to 0 if the plaintext fits in the output
507 : * buffer and to 1 otherwise. */
508 0 : output_too_large = mbedtls_ct_uint_gt(plaintext_size,
509 : plaintext_max_size);
510 :
511 : /* Set ret without branches to avoid timing attacks. Return:
512 : * - INVALID_PADDING if the padding is bad (bad != 0).
513 : * - OUTPUT_TOO_LARGE if the padding is good but the decrypted
514 : * plaintext does not fit in the output buffer.
515 : * - 0 if the padding is correct. */
516 0 : ret = mbedtls_ct_error_if(
517 : bad,
518 : MBEDTLS_ERR_RSA_INVALID_PADDING,
519 : mbedtls_ct_error_if_else_0(output_too_large, MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE)
520 : );
521 :
522 : /* If the padding is bad or the plaintext is too large, zero the
523 : * data that we're about to copy to the output buffer.
524 : * We need to copy the same amount of data
525 : * from the same buffer whether the padding is good or not to
526 : * avoid leaking the padding validity through overall timing or
527 : * through memory or cache access patterns. */
528 0 : mbedtls_ct_zeroize_if(mbedtls_ct_bool_or(bad, output_too_large), input + 11, ilen - 11);
529 :
530 : /* If the plaintext is too large, truncate it to the buffer size.
531 : * Copy anyway to avoid revealing the length through timing, because
532 : * revealing the length is as bad as revealing the padding validity
533 : * for a Bleichenbacher attack. */
534 0 : plaintext_size = mbedtls_ct_uint_if(output_too_large,
535 : (unsigned) plaintext_max_size,
536 : (unsigned) plaintext_size);
537 :
538 : /* Move the plaintext to the leftmost position where it can start in
539 : * the working buffer, i.e. make it start plaintext_max_size from
540 : * the end of the buffer. Do this with a memory access trace that
541 : * does not depend on the plaintext size. After this move, the
542 : * starting location of the plaintext is no longer sensitive
543 : * information. */
544 0 : mbedtls_ct_memmove_left(input + ilen - plaintext_max_size,
545 : plaintext_max_size,
546 : plaintext_max_size - plaintext_size);
547 :
548 : /* Finally copy the decrypted plaintext plus trailing zeros into the output
549 : * buffer. If output_max_len is 0, then output may be an invalid pointer
550 : * and the result of memcpy() would be undefined; prevent undefined
551 : * behavior making sure to depend only on output_max_len (the size of the
552 : * user-provided output buffer), which is independent from plaintext
553 : * length, validity of padding, success of the decryption, and other
554 : * secrets. */
555 0 : if (output_max_len != 0) {
556 0 : memcpy(output, input + ilen - plaintext_max_size, plaintext_max_size);
557 : }
558 :
559 : /* Report the amount of data we copied to the output buffer. In case
560 : * of errors (bad padding or output too large), the value of *olen
561 : * when this function returns is not specified. Making it equivalent
562 : * to the good case limits the risks of leaking the padding validity. */
563 0 : *olen = plaintext_size;
564 :
565 0 : return ret;
566 : }
567 :
568 : #endif /* MBEDTLS_PKCS1_V15 && MBEDTLS_RSA_C && ! MBEDTLS_RSA_ALT */
569 :
570 : #if !defined(MBEDTLS_RSA_ALT)
571 :
572 186 : int mbedtls_rsa_import(mbedtls_rsa_context *ctx,
573 : const mbedtls_mpi *N,
574 : const mbedtls_mpi *P, const mbedtls_mpi *Q,
575 : const mbedtls_mpi *D, const mbedtls_mpi *E)
576 : {
577 186 : int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
578 :
579 186 : if ((N != NULL && (ret = mbedtls_mpi_copy(&ctx->N, N)) != 0) ||
580 186 : (P != NULL && (ret = mbedtls_mpi_copy(&ctx->P, P)) != 0) ||
581 186 : (Q != NULL && (ret = mbedtls_mpi_copy(&ctx->Q, Q)) != 0) ||
582 186 : (D != NULL && (ret = mbedtls_mpi_copy(&ctx->D, D)) != 0) ||
583 38 : (E != NULL && (ret = mbedtls_mpi_copy(&ctx->E, E)) != 0)) {
584 0 : return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret);
585 : }
586 :
587 186 : if (N != NULL) {
588 38 : ctx->len = mbedtls_mpi_size(&ctx->N);
589 : }
590 :
591 186 : return 0;
592 : }
593 :
594 2630 : int mbedtls_rsa_import_raw(mbedtls_rsa_context *ctx,
595 : unsigned char const *N, size_t N_len,
596 : unsigned char const *P, size_t P_len,
597 : unsigned char const *Q, size_t Q_len,
598 : unsigned char const *D, size_t D_len,
599 : unsigned char const *E, size_t E_len)
600 : {
601 2630 : int ret = 0;
602 :
603 2630 : if (N != NULL) {
604 1315 : MBEDTLS_MPI_CHK(mbedtls_mpi_read_binary(&ctx->N, N, N_len));
605 1315 : ctx->len = mbedtls_mpi_size(&ctx->N);
606 : }
607 :
608 2630 : if (P != NULL) {
609 0 : MBEDTLS_MPI_CHK(mbedtls_mpi_read_binary(&ctx->P, P, P_len));
610 : }
611 :
612 2630 : if (Q != NULL) {
613 0 : MBEDTLS_MPI_CHK(mbedtls_mpi_read_binary(&ctx->Q, Q, Q_len));
614 : }
615 :
616 2630 : if (D != NULL) {
617 0 : MBEDTLS_MPI_CHK(mbedtls_mpi_read_binary(&ctx->D, D, D_len));
618 : }
619 :
620 2630 : if (E != NULL) {
621 1315 : MBEDTLS_MPI_CHK(mbedtls_mpi_read_binary(&ctx->E, E, E_len));
622 : }
623 :
624 2630 : cleanup:
625 :
626 2630 : if (ret != 0) {
627 0 : return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret);
628 : }
629 :
630 2630 : return 0;
631 : }
632 :
633 : /*
634 : * Checks whether the context fields are set in such a way
635 : * that the RSA primitives will be able to execute without error.
636 : * It does *not* make guarantees for consistency of the parameters.
637 : */
638 3156 : static int rsa_check_context(mbedtls_rsa_context const *ctx, int is_priv,
639 : int blinding_needed)
640 : {
641 : #if !defined(MBEDTLS_RSA_NO_CRT)
642 : /* blinding_needed is only used for NO_CRT to decide whether
643 : * P,Q need to be present or not. */
644 : ((void) blinding_needed);
645 : #endif
646 :
647 3156 : if (ctx->len != mbedtls_mpi_size(&ctx->N) ||
648 3156 : ctx->len > MBEDTLS_MPI_MAX_SIZE) {
649 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
650 : }
651 :
652 : /*
653 : * 1. Modular exponentiation needs positive, odd moduli.
654 : */
655 :
656 : /* Modular exponentiation wrt. N is always used for
657 : * RSA public key operations. */
658 6312 : if (mbedtls_mpi_cmp_int(&ctx->N, 0) <= 0 ||
659 3156 : mbedtls_mpi_get_bit(&ctx->N, 0) == 0) {
660 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
661 : }
662 :
663 : #if !defined(MBEDTLS_RSA_NO_CRT)
664 : /* Modular exponentiation for P and Q is only
665 : * used for private key operations and if CRT
666 : * is used. */
667 3277 : if (is_priv &&
668 242 : (mbedtls_mpi_cmp_int(&ctx->P, 0) <= 0 ||
669 242 : mbedtls_mpi_get_bit(&ctx->P, 0) == 0 ||
670 242 : mbedtls_mpi_cmp_int(&ctx->Q, 0) <= 0 ||
671 121 : mbedtls_mpi_get_bit(&ctx->Q, 0) == 0)) {
672 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
673 : }
674 : #endif /* !MBEDTLS_RSA_NO_CRT */
675 :
676 : /*
677 : * 2. Exponents must be positive
678 : */
679 :
680 : /* Always need E for public key operations */
681 3156 : if (mbedtls_mpi_cmp_int(&ctx->E, 0) <= 0) {
682 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
683 : }
684 :
685 : #if defined(MBEDTLS_RSA_NO_CRT)
686 : /* For private key operations, use D or DP & DQ
687 : * as (unblinded) exponents. */
688 : if (is_priv && mbedtls_mpi_cmp_int(&ctx->D, 0) <= 0) {
689 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
690 : }
691 : #else
692 3277 : if (is_priv &&
693 242 : (mbedtls_mpi_cmp_int(&ctx->DP, 0) <= 0 ||
694 121 : mbedtls_mpi_cmp_int(&ctx->DQ, 0) <= 0)) {
695 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
696 : }
697 : #endif /* MBEDTLS_RSA_NO_CRT */
698 :
699 : /* Blinding shouldn't make exponents negative either,
700 : * so check that P, Q >= 1 if that hasn't yet been
701 : * done as part of 1. */
702 : #if defined(MBEDTLS_RSA_NO_CRT)
703 : if (is_priv && blinding_needed &&
704 : (mbedtls_mpi_cmp_int(&ctx->P, 0) <= 0 ||
705 : mbedtls_mpi_cmp_int(&ctx->Q, 0) <= 0)) {
706 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
707 : }
708 : #endif
709 :
710 : /* It wouldn't lead to an error if it wasn't satisfied,
711 : * but check for QP >= 1 nonetheless. */
712 : #if !defined(MBEDTLS_RSA_NO_CRT)
713 3277 : if (is_priv &&
714 121 : mbedtls_mpi_cmp_int(&ctx->QP, 0) <= 0) {
715 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
716 : }
717 : #endif
718 :
719 3156 : return 0;
720 : }
721 :
722 1421 : int mbedtls_rsa_complete(mbedtls_rsa_context *ctx)
723 : {
724 1421 : int ret = 0;
725 : int have_N, have_P, have_Q, have_D, have_E;
726 : #if !defined(MBEDTLS_RSA_NO_CRT)
727 : int have_DP, have_DQ, have_QP;
728 : #endif
729 : int n_missing, pq_missing, d_missing, is_pub, is_priv;
730 :
731 1421 : have_N = (mbedtls_mpi_cmp_int(&ctx->N, 0) != 0);
732 1421 : have_P = (mbedtls_mpi_cmp_int(&ctx->P, 0) != 0);
733 1421 : have_Q = (mbedtls_mpi_cmp_int(&ctx->Q, 0) != 0);
734 1421 : have_D = (mbedtls_mpi_cmp_int(&ctx->D, 0) != 0);
735 1421 : have_E = (mbedtls_mpi_cmp_int(&ctx->E, 0) != 0);
736 :
737 : #if !defined(MBEDTLS_RSA_NO_CRT)
738 1421 : have_DP = (mbedtls_mpi_cmp_int(&ctx->DP, 0) != 0);
739 1421 : have_DQ = (mbedtls_mpi_cmp_int(&ctx->DQ, 0) != 0);
740 1421 : have_QP = (mbedtls_mpi_cmp_int(&ctx->QP, 0) != 0);
741 : #endif
742 :
743 : /*
744 : * Check whether provided parameters are enough
745 : * to deduce all others. The following incomplete
746 : * parameter sets for private keys are supported:
747 : *
748 : * (1) P, Q missing.
749 : * (2) D and potentially N missing.
750 : *
751 : */
752 :
753 1421 : n_missing = have_P && have_Q && have_D && have_E;
754 1421 : pq_missing = have_N && !have_P && !have_Q && have_D && have_E;
755 1421 : d_missing = have_P && have_Q && !have_D && have_E;
756 1421 : is_pub = have_N && !have_P && !have_Q && !have_D && have_E;
757 :
758 : /* These three alternatives are mutually exclusive */
759 1421 : is_priv = n_missing || pq_missing || d_missing;
760 :
761 1421 : if (!is_priv && !is_pub) {
762 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
763 : }
764 :
765 : /*
766 : * Step 1: Deduce N if P, Q are provided.
767 : */
768 :
769 1421 : if (!have_N && have_P && have_Q) {
770 0 : if ((ret = mbedtls_mpi_mul_mpi(&ctx->N, &ctx->P,
771 0 : &ctx->Q)) != 0) {
772 0 : return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret);
773 : }
774 :
775 0 : ctx->len = mbedtls_mpi_size(&ctx->N);
776 : }
777 :
778 : /*
779 : * Step 2: Deduce and verify all remaining core parameters.
780 : */
781 :
782 1421 : if (pq_missing) {
783 2 : ret = mbedtls_rsa_deduce_primes(&ctx->N, &ctx->E, &ctx->D,
784 : &ctx->P, &ctx->Q);
785 2 : if (ret != 0) {
786 0 : return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret);
787 : }
788 :
789 1419 : } else if (d_missing) {
790 0 : if ((ret = mbedtls_rsa_deduce_private_exponent(&ctx->P,
791 0 : &ctx->Q,
792 0 : &ctx->E,
793 : &ctx->D)) != 0) {
794 0 : return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret);
795 : }
796 : }
797 :
798 : /*
799 : * Step 3: Deduce all additional parameters specific
800 : * to our current RSA implementation.
801 : */
802 :
803 : #if !defined(MBEDTLS_RSA_NO_CRT)
804 1421 : if (is_priv && !(have_DP && have_DQ && have_QP)) {
805 2 : ret = mbedtls_rsa_deduce_crt(&ctx->P, &ctx->Q, &ctx->D,
806 : &ctx->DP, &ctx->DQ, &ctx->QP);
807 2 : if (ret != 0) {
808 0 : return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret);
809 : }
810 : }
811 : #endif /* MBEDTLS_RSA_NO_CRT */
812 :
813 : /*
814 : * Step 3: Basic sanity checks
815 : */
816 :
817 1421 : return rsa_check_context(ctx, is_priv, 1);
818 : }
819 :
820 0 : int mbedtls_rsa_export_raw(const mbedtls_rsa_context *ctx,
821 : unsigned char *N, size_t N_len,
822 : unsigned char *P, size_t P_len,
823 : unsigned char *Q, size_t Q_len,
824 : unsigned char *D, size_t D_len,
825 : unsigned char *E, size_t E_len)
826 : {
827 0 : int ret = 0;
828 : int is_priv;
829 :
830 : /* Check if key is private or public */
831 0 : is_priv =
832 0 : mbedtls_mpi_cmp_int(&ctx->N, 0) != 0 &&
833 0 : mbedtls_mpi_cmp_int(&ctx->P, 0) != 0 &&
834 0 : mbedtls_mpi_cmp_int(&ctx->Q, 0) != 0 &&
835 0 : mbedtls_mpi_cmp_int(&ctx->D, 0) != 0 &&
836 0 : mbedtls_mpi_cmp_int(&ctx->E, 0) != 0;
837 :
838 0 : if (!is_priv) {
839 : /* If we're trying to export private parameters for a public key,
840 : * something must be wrong. */
841 0 : if (P != NULL || Q != NULL || D != NULL) {
842 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
843 : }
844 :
845 : }
846 :
847 0 : if (N != NULL) {
848 0 : MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary(&ctx->N, N, N_len));
849 : }
850 :
851 0 : if (P != NULL) {
852 0 : MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary(&ctx->P, P, P_len));
853 : }
854 :
855 0 : if (Q != NULL) {
856 0 : MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary(&ctx->Q, Q, Q_len));
857 : }
858 :
859 0 : if (D != NULL) {
860 0 : MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary(&ctx->D, D, D_len));
861 : }
862 :
863 0 : if (E != NULL) {
864 0 : MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary(&ctx->E, E, E_len));
865 : }
866 :
867 0 : cleanup:
868 :
869 0 : return ret;
870 : }
871 :
872 0 : int mbedtls_rsa_export(const mbedtls_rsa_context *ctx,
873 : mbedtls_mpi *N, mbedtls_mpi *P, mbedtls_mpi *Q,
874 : mbedtls_mpi *D, mbedtls_mpi *E)
875 : {
876 0 : int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
877 : int is_priv;
878 :
879 : /* Check if key is private or public */
880 0 : is_priv =
881 0 : mbedtls_mpi_cmp_int(&ctx->N, 0) != 0 &&
882 0 : mbedtls_mpi_cmp_int(&ctx->P, 0) != 0 &&
883 0 : mbedtls_mpi_cmp_int(&ctx->Q, 0) != 0 &&
884 0 : mbedtls_mpi_cmp_int(&ctx->D, 0) != 0 &&
885 0 : mbedtls_mpi_cmp_int(&ctx->E, 0) != 0;
886 :
887 0 : if (!is_priv) {
888 : /* If we're trying to export private parameters for a public key,
889 : * something must be wrong. */
890 0 : if (P != NULL || Q != NULL || D != NULL) {
891 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
892 : }
893 :
894 : }
895 :
896 : /* Export all requested core parameters. */
897 :
898 0 : if ((N != NULL && (ret = mbedtls_mpi_copy(N, &ctx->N)) != 0) ||
899 0 : (P != NULL && (ret = mbedtls_mpi_copy(P, &ctx->P)) != 0) ||
900 0 : (Q != NULL && (ret = mbedtls_mpi_copy(Q, &ctx->Q)) != 0) ||
901 0 : (D != NULL && (ret = mbedtls_mpi_copy(D, &ctx->D)) != 0) ||
902 0 : (E != NULL && (ret = mbedtls_mpi_copy(E, &ctx->E)) != 0)) {
903 0 : return ret;
904 : }
905 :
906 0 : return 0;
907 : }
908 :
909 : /*
910 : * Export CRT parameters
911 : * This must also be implemented if CRT is not used, for being able to
912 : * write DER encoded RSA keys. The helper function mbedtls_rsa_deduce_crt
913 : * can be used in this case.
914 : */
915 0 : int mbedtls_rsa_export_crt(const mbedtls_rsa_context *ctx,
916 : mbedtls_mpi *DP, mbedtls_mpi *DQ, mbedtls_mpi *QP)
917 : {
918 0 : int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
919 : int is_priv;
920 :
921 : /* Check if key is private or public */
922 0 : is_priv =
923 0 : mbedtls_mpi_cmp_int(&ctx->N, 0) != 0 &&
924 0 : mbedtls_mpi_cmp_int(&ctx->P, 0) != 0 &&
925 0 : mbedtls_mpi_cmp_int(&ctx->Q, 0) != 0 &&
926 0 : mbedtls_mpi_cmp_int(&ctx->D, 0) != 0 &&
927 0 : mbedtls_mpi_cmp_int(&ctx->E, 0) != 0;
928 :
929 0 : if (!is_priv) {
930 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
931 : }
932 :
933 : #if !defined(MBEDTLS_RSA_NO_CRT)
934 : /* Export all requested blinding parameters. */
935 0 : if ((DP != NULL && (ret = mbedtls_mpi_copy(DP, &ctx->DP)) != 0) ||
936 0 : (DQ != NULL && (ret = mbedtls_mpi_copy(DQ, &ctx->DQ)) != 0) ||
937 0 : (QP != NULL && (ret = mbedtls_mpi_copy(QP, &ctx->QP)) != 0)) {
938 0 : return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret);
939 : }
940 : #else
941 : if ((ret = mbedtls_rsa_deduce_crt(&ctx->P, &ctx->Q, &ctx->D,
942 : DP, DQ, QP)) != 0) {
943 : return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret);
944 : }
945 : #endif
946 :
947 0 : return 0;
948 : }
949 :
950 : /*
951 : * Initialize an RSA context
952 : */
953 1501 : void mbedtls_rsa_init(mbedtls_rsa_context *ctx)
954 : {
955 1501 : memset(ctx, 0, sizeof(mbedtls_rsa_context));
956 :
957 1501 : ctx->padding = MBEDTLS_RSA_PKCS_V15;
958 1501 : ctx->hash_id = MBEDTLS_MD_NONE;
959 :
960 : #if defined(MBEDTLS_THREADING_C)
961 : /* Set ctx->ver to nonzero to indicate that the mutex has been
962 : * initialized and will need to be freed. */
963 : ctx->ver = 1;
964 : mbedtls_mutex_init(&ctx->mutex);
965 : #endif
966 1501 : }
967 :
968 : /*
969 : * Set padding for an existing RSA context
970 : */
971 70 : int mbedtls_rsa_set_padding(mbedtls_rsa_context *ctx, int padding,
972 : mbedtls_md_type_t hash_id)
973 : {
974 70 : switch (padding) {
975 : #if defined(MBEDTLS_PKCS1_V15)
976 68 : case MBEDTLS_RSA_PKCS_V15:
977 68 : break;
978 : #endif
979 :
980 : #if defined(MBEDTLS_PKCS1_V21)
981 2 : case MBEDTLS_RSA_PKCS_V21:
982 2 : break;
983 : #endif
984 0 : default:
985 0 : return MBEDTLS_ERR_RSA_INVALID_PADDING;
986 : }
987 :
988 : #if defined(MBEDTLS_PKCS1_V21)
989 70 : if ((padding == MBEDTLS_RSA_PKCS_V21) &&
990 : (hash_id != MBEDTLS_MD_NONE)) {
991 : /* Just make sure this hash is supported in this build. */
992 2 : if (mbedtls_md_info_from_type(hash_id) == NULL) {
993 0 : return MBEDTLS_ERR_RSA_INVALID_PADDING;
994 : }
995 : }
996 : #endif /* MBEDTLS_PKCS1_V21 */
997 :
998 70 : ctx->padding = padding;
999 70 : ctx->hash_id = hash_id;
1000 :
1001 70 : return 0;
1002 : }
1003 :
1004 : /*
1005 : * Get padding mode of initialized RSA context
1006 : */
1007 0 : int mbedtls_rsa_get_padding_mode(const mbedtls_rsa_context *ctx)
1008 : {
1009 0 : return ctx->padding;
1010 : }
1011 :
1012 : /*
1013 : * Get hash identifier of mbedtls_md_type_t type
1014 : */
1015 0 : int mbedtls_rsa_get_md_alg(const mbedtls_rsa_context *ctx)
1016 : {
1017 0 : return ctx->hash_id;
1018 : }
1019 :
1020 : /*
1021 : * Get length in bits of RSA modulus
1022 : */
1023 600 : size_t mbedtls_rsa_get_bitlen(const mbedtls_rsa_context *ctx)
1024 : {
1025 600 : return mbedtls_mpi_bitlen(&ctx->N);
1026 : }
1027 :
1028 : /*
1029 : * Get length in bytes of RSA modulus
1030 : */
1031 384 : size_t mbedtls_rsa_get_len(const mbedtls_rsa_context *ctx)
1032 : {
1033 384 : return ctx->len;
1034 : }
1035 :
1036 : #if defined(MBEDTLS_GENPRIME)
1037 :
1038 : /*
1039 : * Generate an RSA keypair
1040 : *
1041 : * This generation method follows the RSA key pair generation procedure of
1042 : * FIPS 186-4 if 2^16 < exponent < 2^256 and nbits = 2048 or nbits = 3072.
1043 : */
1044 0 : int mbedtls_rsa_gen_key(mbedtls_rsa_context *ctx,
1045 : int (*f_rng)(void *, unsigned char *, size_t),
1046 : void *p_rng,
1047 : unsigned int nbits, int exponent)
1048 : {
1049 0 : int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
1050 : mbedtls_mpi H, G, L;
1051 0 : int prime_quality = 0;
1052 :
1053 : /*
1054 : * If the modulus is 1024 bit long or shorter, then the security strength of
1055 : * the RSA algorithm is less than or equal to 80 bits and therefore an error
1056 : * rate of 2^-80 is sufficient.
1057 : */
1058 0 : if (nbits > 1024) {
1059 0 : prime_quality = MBEDTLS_MPI_GEN_PRIME_FLAG_LOW_ERR;
1060 : }
1061 :
1062 0 : mbedtls_mpi_init(&H);
1063 0 : mbedtls_mpi_init(&G);
1064 0 : mbedtls_mpi_init(&L);
1065 :
1066 0 : if (exponent < 3 || nbits % 2 != 0) {
1067 0 : ret = MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
1068 0 : goto cleanup;
1069 : }
1070 :
1071 0 : if (nbits < MBEDTLS_RSA_GEN_KEY_MIN_BITS) {
1072 0 : ret = MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
1073 0 : goto cleanup;
1074 : }
1075 :
1076 : /*
1077 : * find primes P and Q with Q < P so that:
1078 : * 1. |P-Q| > 2^( nbits / 2 - 100 )
1079 : * 2. GCD( E, (P-1)*(Q-1) ) == 1
1080 : * 3. E^-1 mod LCM(P-1, Q-1) > 2^( nbits / 2 )
1081 : */
1082 0 : MBEDTLS_MPI_CHK(mbedtls_mpi_lset(&ctx->E, exponent));
1083 :
1084 : do {
1085 0 : MBEDTLS_MPI_CHK(mbedtls_mpi_gen_prime(&ctx->P, nbits >> 1,
1086 : prime_quality, f_rng, p_rng));
1087 :
1088 0 : MBEDTLS_MPI_CHK(mbedtls_mpi_gen_prime(&ctx->Q, nbits >> 1,
1089 : prime_quality, f_rng, p_rng));
1090 :
1091 : /* make sure the difference between p and q is not too small (FIPS 186-4 §B.3.3 step 5.4) */
1092 0 : MBEDTLS_MPI_CHK(mbedtls_mpi_sub_mpi(&H, &ctx->P, &ctx->Q));
1093 0 : if (mbedtls_mpi_bitlen(&H) <= ((nbits >= 200) ? ((nbits >> 1) - 99) : 0)) {
1094 0 : continue;
1095 : }
1096 :
1097 : /* not required by any standards, but some users rely on the fact that P > Q */
1098 0 : if (H.s < 0) {
1099 0 : mbedtls_mpi_swap(&ctx->P, &ctx->Q);
1100 : }
1101 :
1102 : /* Temporarily replace P,Q by P-1, Q-1 */
1103 0 : MBEDTLS_MPI_CHK(mbedtls_mpi_sub_int(&ctx->P, &ctx->P, 1));
1104 0 : MBEDTLS_MPI_CHK(mbedtls_mpi_sub_int(&ctx->Q, &ctx->Q, 1));
1105 0 : MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&H, &ctx->P, &ctx->Q));
1106 :
1107 : /* check GCD( E, (P-1)*(Q-1) ) == 1 (FIPS 186-4 §B.3.1 criterion 2(a)) */
1108 0 : MBEDTLS_MPI_CHK(mbedtls_mpi_gcd(&G, &ctx->E, &H));
1109 0 : if (mbedtls_mpi_cmp_int(&G, 1) != 0) {
1110 0 : continue;
1111 : }
1112 :
1113 : /* compute smallest possible D = E^-1 mod LCM(P-1, Q-1) (FIPS 186-4 §B.3.1 criterion 3(b)) */
1114 0 : MBEDTLS_MPI_CHK(mbedtls_mpi_gcd(&G, &ctx->P, &ctx->Q));
1115 0 : MBEDTLS_MPI_CHK(mbedtls_mpi_div_mpi(&L, NULL, &H, &G));
1116 0 : MBEDTLS_MPI_CHK(mbedtls_mpi_inv_mod(&ctx->D, &ctx->E, &L));
1117 :
1118 0 : if (mbedtls_mpi_bitlen(&ctx->D) <= ((nbits + 1) / 2)) { // (FIPS 186-4 §B.3.1 criterion 3(a))
1119 0 : continue;
1120 : }
1121 :
1122 0 : break;
1123 : } while (1);
1124 :
1125 : /* Restore P,Q */
1126 0 : MBEDTLS_MPI_CHK(mbedtls_mpi_add_int(&ctx->P, &ctx->P, 1));
1127 0 : MBEDTLS_MPI_CHK(mbedtls_mpi_add_int(&ctx->Q, &ctx->Q, 1));
1128 :
1129 0 : MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&ctx->N, &ctx->P, &ctx->Q));
1130 :
1131 0 : ctx->len = mbedtls_mpi_size(&ctx->N);
1132 :
1133 : #if !defined(MBEDTLS_RSA_NO_CRT)
1134 : /*
1135 : * DP = D mod (P - 1)
1136 : * DQ = D mod (Q - 1)
1137 : * QP = Q^-1 mod P
1138 : */
1139 0 : MBEDTLS_MPI_CHK(mbedtls_rsa_deduce_crt(&ctx->P, &ctx->Q, &ctx->D,
1140 : &ctx->DP, &ctx->DQ, &ctx->QP));
1141 : #endif /* MBEDTLS_RSA_NO_CRT */
1142 :
1143 : /* Double-check */
1144 0 : MBEDTLS_MPI_CHK(mbedtls_rsa_check_privkey(ctx));
1145 :
1146 0 : cleanup:
1147 :
1148 0 : mbedtls_mpi_free(&H);
1149 0 : mbedtls_mpi_free(&G);
1150 0 : mbedtls_mpi_free(&L);
1151 :
1152 0 : if (ret != 0) {
1153 0 : mbedtls_rsa_free(ctx);
1154 :
1155 0 : if ((-ret & ~0x7f) == 0) {
1156 0 : ret = MBEDTLS_ERROR_ADD(MBEDTLS_ERR_RSA_KEY_GEN_FAILED, ret);
1157 : }
1158 0 : return ret;
1159 : }
1160 :
1161 0 : return 0;
1162 : }
1163 :
1164 : #endif /* MBEDTLS_GENPRIME */
1165 :
1166 : /*
1167 : * Check a public RSA key
1168 : */
1169 1351 : int mbedtls_rsa_check_pubkey(const mbedtls_rsa_context *ctx)
1170 : {
1171 1351 : if (rsa_check_context(ctx, 0 /* public */, 0 /* no blinding */) != 0) {
1172 0 : return MBEDTLS_ERR_RSA_KEY_CHECK_FAILED;
1173 : }
1174 :
1175 1351 : if (mbedtls_mpi_bitlen(&ctx->N) < 128) {
1176 0 : return MBEDTLS_ERR_RSA_KEY_CHECK_FAILED;
1177 : }
1178 :
1179 2702 : if (mbedtls_mpi_get_bit(&ctx->E, 0) == 0 ||
1180 2702 : mbedtls_mpi_bitlen(&ctx->E) < 2 ||
1181 1351 : mbedtls_mpi_cmp_mpi(&ctx->E, &ctx->N) >= 0) {
1182 0 : return MBEDTLS_ERR_RSA_KEY_CHECK_FAILED;
1183 : }
1184 :
1185 1351 : return 0;
1186 : }
1187 :
1188 : /*
1189 : * Check for the consistency of all fields in an RSA private key context
1190 : */
1191 0 : int mbedtls_rsa_check_privkey(const mbedtls_rsa_context *ctx)
1192 : {
1193 0 : if (mbedtls_rsa_check_pubkey(ctx) != 0 ||
1194 0 : rsa_check_context(ctx, 1 /* private */, 1 /* blinding */) != 0) {
1195 0 : return MBEDTLS_ERR_RSA_KEY_CHECK_FAILED;
1196 : }
1197 :
1198 0 : if (mbedtls_rsa_validate_params(&ctx->N, &ctx->P, &ctx->Q,
1199 : &ctx->D, &ctx->E, NULL, NULL) != 0) {
1200 0 : return MBEDTLS_ERR_RSA_KEY_CHECK_FAILED;
1201 : }
1202 :
1203 : #if !defined(MBEDTLS_RSA_NO_CRT)
1204 0 : else if (mbedtls_rsa_validate_crt(&ctx->P, &ctx->Q, &ctx->D,
1205 : &ctx->DP, &ctx->DQ, &ctx->QP) != 0) {
1206 0 : return MBEDTLS_ERR_RSA_KEY_CHECK_FAILED;
1207 : }
1208 : #endif
1209 :
1210 0 : return 0;
1211 : }
1212 :
1213 : /*
1214 : * Check if contexts holding a public and private key match
1215 : */
1216 0 : int mbedtls_rsa_check_pub_priv(const mbedtls_rsa_context *pub,
1217 : const mbedtls_rsa_context *prv)
1218 : {
1219 0 : if (mbedtls_rsa_check_pubkey(pub) != 0 ||
1220 0 : mbedtls_rsa_check_privkey(prv) != 0) {
1221 0 : return MBEDTLS_ERR_RSA_KEY_CHECK_FAILED;
1222 : }
1223 :
1224 0 : if (mbedtls_mpi_cmp_mpi(&pub->N, &prv->N) != 0 ||
1225 0 : mbedtls_mpi_cmp_mpi(&pub->E, &prv->E) != 0) {
1226 0 : return MBEDTLS_ERR_RSA_KEY_CHECK_FAILED;
1227 : }
1228 :
1229 0 : return 0;
1230 : }
1231 :
1232 : /*
1233 : * Do an RSA public key operation
1234 : */
1235 346 : int mbedtls_rsa_public(mbedtls_rsa_context *ctx,
1236 : const unsigned char *input,
1237 : unsigned char *output)
1238 : {
1239 346 : int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
1240 : size_t olen;
1241 : mbedtls_mpi T;
1242 :
1243 346 : if (rsa_check_context(ctx, 0 /* public */, 0 /* no blinding */)) {
1244 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
1245 : }
1246 :
1247 346 : mbedtls_mpi_init(&T);
1248 :
1249 : #if defined(MBEDTLS_THREADING_C)
1250 : if ((ret = mbedtls_mutex_lock(&ctx->mutex)) != 0) {
1251 : return ret;
1252 : }
1253 : #endif
1254 :
1255 346 : MBEDTLS_MPI_CHK(mbedtls_mpi_read_binary(&T, input, ctx->len));
1256 :
1257 346 : if (mbedtls_mpi_cmp_mpi(&T, &ctx->N) >= 0) {
1258 0 : ret = MBEDTLS_ERR_MPI_BAD_INPUT_DATA;
1259 0 : goto cleanup;
1260 : }
1261 :
1262 346 : olen = ctx->len;
1263 346 : MBEDTLS_MPI_CHK(mbedtls_mpi_exp_mod_unsafe(&T, &T, &ctx->E, &ctx->N, &ctx->RN));
1264 346 : MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary(&T, output, olen));
1265 :
1266 346 : cleanup:
1267 : #if defined(MBEDTLS_THREADING_C)
1268 : if (mbedtls_mutex_unlock(&ctx->mutex) != 0) {
1269 : return MBEDTLS_ERR_THREADING_MUTEX_ERROR;
1270 : }
1271 : #endif
1272 :
1273 346 : mbedtls_mpi_free(&T);
1274 :
1275 346 : if (ret != 0) {
1276 0 : return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_RSA_PUBLIC_FAILED, ret);
1277 : }
1278 :
1279 346 : return 0;
1280 : }
1281 :
1282 : /*
1283 : * Generate or update blinding values, see section 10 of:
1284 : * KOCHER, Paul C. Timing attacks on implementations of Diffie-Hellman, RSA,
1285 : * DSS, and other systems. In : Advances in Cryptology-CRYPTO'96. Springer
1286 : * Berlin Heidelberg, 1996. p. 104-113.
1287 : */
1288 38 : static int rsa_prepare_blinding(mbedtls_rsa_context *ctx,
1289 : int (*f_rng)(void *, unsigned char *, size_t), void *p_rng)
1290 : {
1291 38 : int ret, count = 0;
1292 : mbedtls_mpi R;
1293 :
1294 38 : mbedtls_mpi_init(&R);
1295 :
1296 38 : if (ctx->Vf.p != NULL) {
1297 : /* We already have blinding values, just update them by squaring */
1298 0 : MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&ctx->Vi, &ctx->Vi, &ctx->Vi));
1299 0 : MBEDTLS_MPI_CHK(mbedtls_mpi_mod_mpi(&ctx->Vi, &ctx->Vi, &ctx->N));
1300 0 : MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&ctx->Vf, &ctx->Vf, &ctx->Vf));
1301 0 : MBEDTLS_MPI_CHK(mbedtls_mpi_mod_mpi(&ctx->Vf, &ctx->Vf, &ctx->N));
1302 :
1303 0 : goto cleanup;
1304 : }
1305 :
1306 : /* Unblinding value: Vf = random number, invertible mod N */
1307 : do {
1308 38 : if (count++ > 10) {
1309 0 : ret = MBEDTLS_ERR_RSA_RNG_FAILED;
1310 0 : goto cleanup;
1311 : }
1312 :
1313 38 : MBEDTLS_MPI_CHK(mbedtls_mpi_fill_random(&ctx->Vf, ctx->len - 1, f_rng, p_rng));
1314 :
1315 : /* Compute Vf^-1 as R * (R Vf)^-1 to avoid leaks from inv_mod. */
1316 38 : MBEDTLS_MPI_CHK(mbedtls_mpi_fill_random(&R, ctx->len - 1, f_rng, p_rng));
1317 38 : MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&ctx->Vi, &ctx->Vf, &R));
1318 38 : MBEDTLS_MPI_CHK(mbedtls_mpi_mod_mpi(&ctx->Vi, &ctx->Vi, &ctx->N));
1319 :
1320 : /* At this point, Vi is invertible mod N if and only if both Vf and R
1321 : * are invertible mod N. If one of them isn't, we don't need to know
1322 : * which one, we just loop and choose new values for both of them.
1323 : * (Each iteration succeeds with overwhelming probability.) */
1324 38 : ret = mbedtls_mpi_inv_mod(&ctx->Vi, &ctx->Vi, &ctx->N);
1325 38 : if (ret != 0 && ret != MBEDTLS_ERR_MPI_NOT_ACCEPTABLE) {
1326 0 : goto cleanup;
1327 : }
1328 :
1329 38 : } while (ret == MBEDTLS_ERR_MPI_NOT_ACCEPTABLE);
1330 :
1331 : /* Finish the computation of Vf^-1 = R * (R Vf)^-1 */
1332 38 : MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&ctx->Vi, &ctx->Vi, &R));
1333 38 : MBEDTLS_MPI_CHK(mbedtls_mpi_mod_mpi(&ctx->Vi, &ctx->Vi, &ctx->N));
1334 :
1335 : /* Blinding value: Vi = Vf^(-e) mod N
1336 : * (Vi already contains Vf^-1 at this point) */
1337 38 : MBEDTLS_MPI_CHK(mbedtls_mpi_exp_mod(&ctx->Vi, &ctx->Vi, &ctx->E, &ctx->N, &ctx->RN));
1338 :
1339 :
1340 38 : cleanup:
1341 38 : mbedtls_mpi_free(&R);
1342 :
1343 38 : return ret;
1344 : }
1345 :
1346 : /*
1347 : * Unblind
1348 : * T = T * Vf mod N
1349 : */
1350 38 : static int rsa_unblind(mbedtls_mpi *T, mbedtls_mpi *Vf, const mbedtls_mpi *N)
1351 : {
1352 38 : int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
1353 38 : const mbedtls_mpi_uint mm = mbedtls_mpi_core_montmul_init(N->p);
1354 38 : const size_t nlimbs = N->n;
1355 38 : const size_t tlimbs = mbedtls_mpi_core_montmul_working_limbs(nlimbs);
1356 : mbedtls_mpi RR, M_T;
1357 :
1358 38 : mbedtls_mpi_init(&RR);
1359 38 : mbedtls_mpi_init(&M_T);
1360 :
1361 38 : MBEDTLS_MPI_CHK(mbedtls_mpi_core_get_mont_r2_unsafe(&RR, N));
1362 38 : MBEDTLS_MPI_CHK(mbedtls_mpi_grow(&M_T, tlimbs));
1363 :
1364 38 : MBEDTLS_MPI_CHK(mbedtls_mpi_grow(T, nlimbs));
1365 38 : MBEDTLS_MPI_CHK(mbedtls_mpi_grow(Vf, nlimbs));
1366 :
1367 : /* T = T * Vf mod N
1368 : * Reminder: montmul(A, B, N) = A * B * R^-1 mod N
1369 : * Usually both operands are multiplied by R mod N beforehand (by calling
1370 : * `to_mont_rep()` on them), yielding a result that's also * R mod N (aka
1371 : * "in the Montgomery domain"). Here we only multiply one operand by R mod
1372 : * N, so the result is directly what we want - no need to call
1373 : * `from_mont_rep()` on it. */
1374 38 : mbedtls_mpi_core_to_mont_rep(T->p, T->p, N->p, nlimbs, mm, RR.p, M_T.p);
1375 38 : mbedtls_mpi_core_montmul(T->p, T->p, Vf->p, nlimbs, N->p, nlimbs, mm, M_T.p);
1376 :
1377 38 : cleanup:
1378 :
1379 38 : mbedtls_mpi_free(&RR);
1380 38 : mbedtls_mpi_free(&M_T);
1381 :
1382 38 : return ret;
1383 : }
1384 :
1385 : /*
1386 : * Exponent blinding supposed to prevent side-channel attacks using multiple
1387 : * traces of measurements to recover the RSA key. The more collisions are there,
1388 : * the more bits of the key can be recovered. See [3].
1389 : *
1390 : * Collecting n collisions with m bit long blinding value requires 2^(m-m/n)
1391 : * observations on average.
1392 : *
1393 : * For example with 28 byte blinding to achieve 2 collisions the adversary has
1394 : * to make 2^112 observations on average.
1395 : *
1396 : * (With the currently (as of 2017 April) known best algorithms breaking 2048
1397 : * bit RSA requires approximately as much time as trying out 2^112 random keys.
1398 : * Thus in this sense with 28 byte blinding the security is not reduced by
1399 : * side-channel attacks like the one in [3])
1400 : *
1401 : * This countermeasure does not help if the key recovery is possible with a
1402 : * single trace.
1403 : */
1404 : #define RSA_EXPONENT_BLINDING 28
1405 :
1406 : /*
1407 : * Do an RSA private key operation
1408 : */
1409 38 : int mbedtls_rsa_private(mbedtls_rsa_context *ctx,
1410 : int (*f_rng)(void *, unsigned char *, size_t),
1411 : void *p_rng,
1412 : const unsigned char *input,
1413 : unsigned char *output)
1414 : {
1415 38 : int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
1416 : size_t olen;
1417 :
1418 : /* Temporary holding the result */
1419 : mbedtls_mpi T;
1420 :
1421 : /* Temporaries holding P-1, Q-1 and the
1422 : * exponent blinding factor, respectively. */
1423 : mbedtls_mpi P1, Q1, R;
1424 :
1425 : #if !defined(MBEDTLS_RSA_NO_CRT)
1426 : /* Temporaries holding the results mod p resp. mod q. */
1427 : mbedtls_mpi TP, TQ;
1428 :
1429 : /* Temporaries holding the blinded exponents for
1430 : * the mod p resp. mod q computation (if used). */
1431 : mbedtls_mpi DP_blind, DQ_blind;
1432 : #else
1433 : /* Temporary holding the blinded exponent (if used). */
1434 : mbedtls_mpi D_blind;
1435 : #endif /* MBEDTLS_RSA_NO_CRT */
1436 :
1437 : /* Temporaries holding the initial input and the double
1438 : * checked result; should be the same in the end. */
1439 : mbedtls_mpi input_blinded, check_result_blinded;
1440 :
1441 38 : if (f_rng == NULL) {
1442 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
1443 : }
1444 :
1445 38 : if (rsa_check_context(ctx, 1 /* private key checks */,
1446 : 1 /* blinding on */) != 0) {
1447 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
1448 : }
1449 :
1450 : #if defined(MBEDTLS_THREADING_C)
1451 : if ((ret = mbedtls_mutex_lock(&ctx->mutex)) != 0) {
1452 : return ret;
1453 : }
1454 : #endif
1455 :
1456 : /* MPI Initialization */
1457 38 : mbedtls_mpi_init(&T);
1458 :
1459 38 : mbedtls_mpi_init(&P1);
1460 38 : mbedtls_mpi_init(&Q1);
1461 38 : mbedtls_mpi_init(&R);
1462 :
1463 : #if defined(MBEDTLS_RSA_NO_CRT)
1464 : mbedtls_mpi_init(&D_blind);
1465 : #else
1466 38 : mbedtls_mpi_init(&DP_blind);
1467 38 : mbedtls_mpi_init(&DQ_blind);
1468 : #endif
1469 :
1470 : #if !defined(MBEDTLS_RSA_NO_CRT)
1471 38 : mbedtls_mpi_init(&TP); mbedtls_mpi_init(&TQ);
1472 : #endif
1473 :
1474 38 : mbedtls_mpi_init(&input_blinded);
1475 38 : mbedtls_mpi_init(&check_result_blinded);
1476 :
1477 : /* End of MPI initialization */
1478 :
1479 38 : MBEDTLS_MPI_CHK(mbedtls_mpi_read_binary(&T, input, ctx->len));
1480 38 : if (mbedtls_mpi_cmp_mpi(&T, &ctx->N) >= 0) {
1481 0 : ret = MBEDTLS_ERR_MPI_BAD_INPUT_DATA;
1482 0 : goto cleanup;
1483 : }
1484 :
1485 : /*
1486 : * Blinding
1487 : * T = T * Vi mod N
1488 : */
1489 38 : MBEDTLS_MPI_CHK(rsa_prepare_blinding(ctx, f_rng, p_rng));
1490 38 : MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&T, &T, &ctx->Vi));
1491 38 : MBEDTLS_MPI_CHK(mbedtls_mpi_mod_mpi(&T, &T, &ctx->N));
1492 :
1493 38 : MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&input_blinded, &T));
1494 :
1495 : /*
1496 : * Exponent blinding
1497 : */
1498 38 : MBEDTLS_MPI_CHK(mbedtls_mpi_sub_int(&P1, &ctx->P, 1));
1499 38 : MBEDTLS_MPI_CHK(mbedtls_mpi_sub_int(&Q1, &ctx->Q, 1));
1500 :
1501 : #if defined(MBEDTLS_RSA_NO_CRT)
1502 : /*
1503 : * D_blind = ( P - 1 ) * ( Q - 1 ) * R + D
1504 : */
1505 : MBEDTLS_MPI_CHK(mbedtls_mpi_fill_random(&R, RSA_EXPONENT_BLINDING,
1506 : f_rng, p_rng));
1507 : MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&D_blind, &P1, &Q1));
1508 : MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&D_blind, &D_blind, &R));
1509 : MBEDTLS_MPI_CHK(mbedtls_mpi_add_mpi(&D_blind, &D_blind, &ctx->D));
1510 : #else
1511 : /*
1512 : * DP_blind = ( P - 1 ) * R + DP
1513 : */
1514 38 : MBEDTLS_MPI_CHK(mbedtls_mpi_fill_random(&R, RSA_EXPONENT_BLINDING,
1515 : f_rng, p_rng));
1516 38 : MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&DP_blind, &P1, &R));
1517 38 : MBEDTLS_MPI_CHK(mbedtls_mpi_add_mpi(&DP_blind, &DP_blind,
1518 : &ctx->DP));
1519 :
1520 : /*
1521 : * DQ_blind = ( Q - 1 ) * R + DQ
1522 : */
1523 38 : MBEDTLS_MPI_CHK(mbedtls_mpi_fill_random(&R, RSA_EXPONENT_BLINDING,
1524 : f_rng, p_rng));
1525 38 : MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&DQ_blind, &Q1, &R));
1526 38 : MBEDTLS_MPI_CHK(mbedtls_mpi_add_mpi(&DQ_blind, &DQ_blind,
1527 : &ctx->DQ));
1528 : #endif /* MBEDTLS_RSA_NO_CRT */
1529 :
1530 : #if defined(MBEDTLS_RSA_NO_CRT)
1531 : MBEDTLS_MPI_CHK(mbedtls_mpi_exp_mod(&T, &T, &D_blind, &ctx->N, &ctx->RN));
1532 : #else
1533 : /*
1534 : * Faster decryption using the CRT
1535 : *
1536 : * TP = input ^ dP mod P
1537 : * TQ = input ^ dQ mod Q
1538 : */
1539 :
1540 38 : MBEDTLS_MPI_CHK(mbedtls_mpi_exp_mod(&TP, &T, &DP_blind, &ctx->P, &ctx->RP));
1541 38 : MBEDTLS_MPI_CHK(mbedtls_mpi_exp_mod(&TQ, &T, &DQ_blind, &ctx->Q, &ctx->RQ));
1542 :
1543 : /*
1544 : * T = (TP - TQ) * (Q^-1 mod P) mod P
1545 : */
1546 38 : MBEDTLS_MPI_CHK(mbedtls_mpi_sub_mpi(&T, &TP, &TQ));
1547 38 : MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&TP, &T, &ctx->QP));
1548 38 : MBEDTLS_MPI_CHK(mbedtls_mpi_mod_mpi(&T, &TP, &ctx->P));
1549 :
1550 : /*
1551 : * T = TQ + T * Q
1552 : */
1553 38 : MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&TP, &T, &ctx->Q));
1554 38 : MBEDTLS_MPI_CHK(mbedtls_mpi_add_mpi(&T, &TQ, &TP));
1555 : #endif /* MBEDTLS_RSA_NO_CRT */
1556 :
1557 : /* Verify the result to prevent glitching attacks. */
1558 38 : MBEDTLS_MPI_CHK(mbedtls_mpi_exp_mod(&check_result_blinded, &T, &ctx->E,
1559 : &ctx->N, &ctx->RN));
1560 38 : if (mbedtls_mpi_cmp_mpi(&check_result_blinded, &input_blinded) != 0) {
1561 0 : ret = MBEDTLS_ERR_RSA_VERIFY_FAILED;
1562 0 : goto cleanup;
1563 : }
1564 :
1565 : /*
1566 : * Unblind
1567 : * T = T * Vf mod N
1568 : */
1569 38 : MBEDTLS_MPI_CHK(rsa_unblind(&T, &ctx->Vf, &ctx->N));
1570 :
1571 38 : olen = ctx->len;
1572 38 : MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary(&T, output, olen));
1573 :
1574 38 : cleanup:
1575 : #if defined(MBEDTLS_THREADING_C)
1576 : if (mbedtls_mutex_unlock(&ctx->mutex) != 0) {
1577 : return MBEDTLS_ERR_THREADING_MUTEX_ERROR;
1578 : }
1579 : #endif
1580 :
1581 38 : mbedtls_mpi_free(&P1);
1582 38 : mbedtls_mpi_free(&Q1);
1583 38 : mbedtls_mpi_free(&R);
1584 :
1585 : #if defined(MBEDTLS_RSA_NO_CRT)
1586 : mbedtls_mpi_free(&D_blind);
1587 : #else
1588 38 : mbedtls_mpi_free(&DP_blind);
1589 38 : mbedtls_mpi_free(&DQ_blind);
1590 : #endif
1591 :
1592 38 : mbedtls_mpi_free(&T);
1593 :
1594 : #if !defined(MBEDTLS_RSA_NO_CRT)
1595 38 : mbedtls_mpi_free(&TP); mbedtls_mpi_free(&TQ);
1596 : #endif
1597 :
1598 38 : mbedtls_mpi_free(&check_result_blinded);
1599 38 : mbedtls_mpi_free(&input_blinded);
1600 :
1601 38 : if (ret != 0 && ret >= -0x007f) {
1602 0 : return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_RSA_PRIVATE_FAILED, ret);
1603 : }
1604 :
1605 38 : return ret;
1606 : }
1607 :
1608 : #if defined(MBEDTLS_PKCS1_V21)
1609 : /**
1610 : * Generate and apply the MGF1 operation (from PKCS#1 v2.1) to a buffer.
1611 : *
1612 : * \param dst buffer to mask
1613 : * \param dlen length of destination buffer
1614 : * \param src source of the mask generation
1615 : * \param slen length of the source buffer
1616 : * \param md_alg message digest to use
1617 : */
1618 2 : static int mgf_mask(unsigned char *dst, size_t dlen, unsigned char *src,
1619 : size_t slen, mbedtls_md_type_t md_alg)
1620 : {
1621 : unsigned char counter[4];
1622 : unsigned char *p;
1623 : unsigned int hlen;
1624 : size_t i, use_len;
1625 : unsigned char mask[MBEDTLS_MD_MAX_SIZE];
1626 2 : int ret = 0;
1627 : const mbedtls_md_info_t *md_info;
1628 : mbedtls_md_context_t md_ctx;
1629 :
1630 2 : mbedtls_md_init(&md_ctx);
1631 2 : md_info = mbedtls_md_info_from_type(md_alg);
1632 2 : if (md_info == NULL) {
1633 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
1634 : }
1635 :
1636 2 : mbedtls_md_init(&md_ctx);
1637 2 : if ((ret = mbedtls_md_setup(&md_ctx, md_info, 0)) != 0) {
1638 0 : goto exit;
1639 : }
1640 :
1641 2 : hlen = mbedtls_md_get_size(md_info);
1642 :
1643 2 : memset(mask, 0, sizeof(mask));
1644 2 : memset(counter, 0, 4);
1645 :
1646 : /* Generate and apply dbMask */
1647 2 : p = dst;
1648 :
1649 16 : while (dlen > 0) {
1650 14 : use_len = hlen;
1651 14 : if (dlen < hlen) {
1652 2 : use_len = dlen;
1653 : }
1654 :
1655 14 : if ((ret = mbedtls_md_starts(&md_ctx)) != 0) {
1656 0 : goto exit;
1657 : }
1658 14 : if ((ret = mbedtls_md_update(&md_ctx, src, slen)) != 0) {
1659 0 : goto exit;
1660 : }
1661 14 : if ((ret = mbedtls_md_update(&md_ctx, counter, 4)) != 0) {
1662 0 : goto exit;
1663 : }
1664 14 : if ((ret = mbedtls_md_finish(&md_ctx, mask)) != 0) {
1665 0 : goto exit;
1666 : }
1667 :
1668 460 : for (i = 0; i < use_len; ++i) {
1669 446 : *p++ ^= mask[i];
1670 : }
1671 :
1672 14 : counter[3]++;
1673 :
1674 14 : dlen -= use_len;
1675 : }
1676 :
1677 2 : exit:
1678 2 : mbedtls_platform_zeroize(mask, sizeof(mask));
1679 2 : mbedtls_md_free(&md_ctx);
1680 :
1681 2 : return ret;
1682 : }
1683 :
1684 : /**
1685 : * Generate Hash(M') as in RFC 8017 page 43 points 5 and 6.
1686 : *
1687 : * \param hash the input hash
1688 : * \param hlen length of the input hash
1689 : * \param salt the input salt
1690 : * \param slen length of the input salt
1691 : * \param out the output buffer - must be large enough for \p md_alg
1692 : * \param md_alg message digest to use
1693 : */
1694 2 : static int hash_mprime(const unsigned char *hash, size_t hlen,
1695 : const unsigned char *salt, size_t slen,
1696 : unsigned char *out, mbedtls_md_type_t md_alg)
1697 : {
1698 2 : const unsigned char zeros[8] = { 0, 0, 0, 0, 0, 0, 0, 0 };
1699 :
1700 : mbedtls_md_context_t md_ctx;
1701 2 : int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
1702 :
1703 2 : const mbedtls_md_info_t *md_info = mbedtls_md_info_from_type(md_alg);
1704 2 : if (md_info == NULL) {
1705 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
1706 : }
1707 :
1708 2 : mbedtls_md_init(&md_ctx);
1709 2 : if ((ret = mbedtls_md_setup(&md_ctx, md_info, 0)) != 0) {
1710 0 : goto exit;
1711 : }
1712 2 : if ((ret = mbedtls_md_starts(&md_ctx)) != 0) {
1713 0 : goto exit;
1714 : }
1715 2 : if ((ret = mbedtls_md_update(&md_ctx, zeros, sizeof(zeros))) != 0) {
1716 0 : goto exit;
1717 : }
1718 2 : if ((ret = mbedtls_md_update(&md_ctx, hash, hlen)) != 0) {
1719 0 : goto exit;
1720 : }
1721 2 : if ((ret = mbedtls_md_update(&md_ctx, salt, slen)) != 0) {
1722 0 : goto exit;
1723 : }
1724 2 : if ((ret = mbedtls_md_finish(&md_ctx, out)) != 0) {
1725 0 : goto exit;
1726 : }
1727 :
1728 2 : exit:
1729 2 : mbedtls_md_free(&md_ctx);
1730 :
1731 2 : return ret;
1732 : }
1733 :
1734 : /**
1735 : * Compute a hash.
1736 : *
1737 : * \param md_alg algorithm to use
1738 : * \param input input message to hash
1739 : * \param ilen input length
1740 : * \param output the output buffer - must be large enough for \p md_alg
1741 : */
1742 0 : static int compute_hash(mbedtls_md_type_t md_alg,
1743 : const unsigned char *input, size_t ilen,
1744 : unsigned char *output)
1745 : {
1746 : const mbedtls_md_info_t *md_info;
1747 :
1748 0 : md_info = mbedtls_md_info_from_type(md_alg);
1749 0 : if (md_info == NULL) {
1750 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
1751 : }
1752 :
1753 0 : return mbedtls_md(md_info, input, ilen, output);
1754 : }
1755 : #endif /* MBEDTLS_PKCS1_V21 */
1756 :
1757 : #if defined(MBEDTLS_PKCS1_V21)
1758 : /*
1759 : * Implementation of the PKCS#1 v2.1 RSAES-OAEP-ENCRYPT function
1760 : */
1761 0 : int mbedtls_rsa_rsaes_oaep_encrypt(mbedtls_rsa_context *ctx,
1762 : int (*f_rng)(void *, unsigned char *, size_t),
1763 : void *p_rng,
1764 : const unsigned char *label, size_t label_len,
1765 : size_t ilen,
1766 : const unsigned char *input,
1767 : unsigned char *output)
1768 : {
1769 : size_t olen;
1770 0 : int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
1771 0 : unsigned char *p = output;
1772 : unsigned int hlen;
1773 :
1774 0 : if (f_rng == NULL) {
1775 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
1776 : }
1777 :
1778 0 : hlen = mbedtls_md_get_size_from_type((mbedtls_md_type_t) ctx->hash_id);
1779 0 : if (hlen == 0) {
1780 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
1781 : }
1782 :
1783 0 : olen = ctx->len;
1784 :
1785 : /* first comparison checks for overflow */
1786 0 : if (ilen + 2 * hlen + 2 < ilen || olen < ilen + 2 * hlen + 2) {
1787 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
1788 : }
1789 :
1790 0 : memset(output, 0, olen);
1791 :
1792 0 : *p++ = 0;
1793 :
1794 : /* Generate a random octet string seed */
1795 0 : if ((ret = f_rng(p_rng, p, hlen)) != 0) {
1796 0 : return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_RSA_RNG_FAILED, ret);
1797 : }
1798 :
1799 0 : p += hlen;
1800 :
1801 : /* Construct DB */
1802 0 : ret = compute_hash((mbedtls_md_type_t) ctx->hash_id, label, label_len, p);
1803 0 : if (ret != 0) {
1804 0 : return ret;
1805 : }
1806 0 : p += hlen;
1807 0 : p += olen - 2 * hlen - 2 - ilen;
1808 0 : *p++ = 1;
1809 0 : if (ilen != 0) {
1810 0 : memcpy(p, input, ilen);
1811 : }
1812 :
1813 : /* maskedDB: Apply dbMask to DB */
1814 0 : if ((ret = mgf_mask(output + hlen + 1, olen - hlen - 1, output + 1, hlen,
1815 0 : (mbedtls_md_type_t) ctx->hash_id)) != 0) {
1816 0 : return ret;
1817 : }
1818 :
1819 : /* maskedSeed: Apply seedMask to seed */
1820 0 : if ((ret = mgf_mask(output + 1, hlen, output + hlen + 1, olen - hlen - 1,
1821 0 : (mbedtls_md_type_t) ctx->hash_id)) != 0) {
1822 0 : return ret;
1823 : }
1824 :
1825 0 : return mbedtls_rsa_public(ctx, output, output);
1826 : }
1827 : #endif /* MBEDTLS_PKCS1_V21 */
1828 :
1829 : #if defined(MBEDTLS_PKCS1_V15)
1830 : /*
1831 : * Implementation of the PKCS#1 v2.1 RSAES-PKCS1-V1_5-ENCRYPT function
1832 : */
1833 0 : int mbedtls_rsa_rsaes_pkcs1_v15_encrypt(mbedtls_rsa_context *ctx,
1834 : int (*f_rng)(void *, unsigned char *, size_t),
1835 : void *p_rng, size_t ilen,
1836 : const unsigned char *input,
1837 : unsigned char *output)
1838 : {
1839 : size_t nb_pad, olen;
1840 0 : int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
1841 0 : unsigned char *p = output;
1842 :
1843 0 : olen = ctx->len;
1844 :
1845 : /* first comparison checks for overflow */
1846 0 : if (ilen + 11 < ilen || olen < ilen + 11) {
1847 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
1848 : }
1849 :
1850 0 : nb_pad = olen - 3 - ilen;
1851 :
1852 0 : *p++ = 0;
1853 :
1854 0 : if (f_rng == NULL) {
1855 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
1856 : }
1857 :
1858 0 : *p++ = MBEDTLS_RSA_CRYPT;
1859 :
1860 0 : while (nb_pad-- > 0) {
1861 0 : int rng_dl = 100;
1862 :
1863 : do {
1864 0 : ret = f_rng(p_rng, p, 1);
1865 0 : } while (*p == 0 && --rng_dl && ret == 0);
1866 :
1867 : /* Check if RNG failed to generate data */
1868 0 : if (rng_dl == 0 || ret != 0) {
1869 0 : return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_RSA_RNG_FAILED, ret);
1870 : }
1871 :
1872 0 : p++;
1873 : }
1874 :
1875 0 : *p++ = 0;
1876 0 : if (ilen != 0) {
1877 0 : memcpy(p, input, ilen);
1878 : }
1879 :
1880 0 : return mbedtls_rsa_public(ctx, output, output);
1881 : }
1882 : #endif /* MBEDTLS_PKCS1_V15 */
1883 :
1884 : /*
1885 : * Add the message padding, then do an RSA operation
1886 : */
1887 0 : int mbedtls_rsa_pkcs1_encrypt(mbedtls_rsa_context *ctx,
1888 : int (*f_rng)(void *, unsigned char *, size_t),
1889 : void *p_rng,
1890 : size_t ilen,
1891 : const unsigned char *input,
1892 : unsigned char *output)
1893 : {
1894 0 : switch (ctx->padding) {
1895 : #if defined(MBEDTLS_PKCS1_V15)
1896 0 : case MBEDTLS_RSA_PKCS_V15:
1897 0 : return mbedtls_rsa_rsaes_pkcs1_v15_encrypt(ctx, f_rng, p_rng,
1898 : ilen, input, output);
1899 : #endif
1900 :
1901 : #if defined(MBEDTLS_PKCS1_V21)
1902 0 : case MBEDTLS_RSA_PKCS_V21:
1903 0 : return mbedtls_rsa_rsaes_oaep_encrypt(ctx, f_rng, p_rng, NULL, 0,
1904 : ilen, input, output);
1905 : #endif
1906 :
1907 0 : default:
1908 0 : return MBEDTLS_ERR_RSA_INVALID_PADDING;
1909 : }
1910 : }
1911 :
1912 : #if defined(MBEDTLS_PKCS1_V21)
1913 : /*
1914 : * Implementation of the PKCS#1 v2.1 RSAES-OAEP-DECRYPT function
1915 : */
1916 0 : int mbedtls_rsa_rsaes_oaep_decrypt(mbedtls_rsa_context *ctx,
1917 : int (*f_rng)(void *, unsigned char *, size_t),
1918 : void *p_rng,
1919 : const unsigned char *label, size_t label_len,
1920 : size_t *olen,
1921 : const unsigned char *input,
1922 : unsigned char *output,
1923 : size_t output_max_len)
1924 : {
1925 0 : int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
1926 : size_t ilen, i, pad_len;
1927 : unsigned char *p;
1928 : mbedtls_ct_condition_t bad, in_padding;
1929 : unsigned char buf[MBEDTLS_MPI_MAX_SIZE];
1930 : unsigned char lhash[MBEDTLS_MD_MAX_SIZE];
1931 : unsigned int hlen;
1932 :
1933 : /*
1934 : * Parameters sanity checks
1935 : */
1936 0 : if (ctx->padding != MBEDTLS_RSA_PKCS_V21) {
1937 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
1938 : }
1939 :
1940 0 : ilen = ctx->len;
1941 :
1942 0 : if (ilen < 16 || ilen > sizeof(buf)) {
1943 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
1944 : }
1945 :
1946 0 : hlen = mbedtls_md_get_size_from_type((mbedtls_md_type_t) ctx->hash_id);
1947 0 : if (hlen == 0) {
1948 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
1949 : }
1950 :
1951 : // checking for integer underflow
1952 0 : if (2 * hlen + 2 > ilen) {
1953 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
1954 : }
1955 :
1956 : /*
1957 : * RSA operation
1958 : */
1959 0 : ret = mbedtls_rsa_private(ctx, f_rng, p_rng, input, buf);
1960 :
1961 0 : if (ret != 0) {
1962 0 : goto cleanup;
1963 : }
1964 :
1965 : /*
1966 : * Unmask data and generate lHash
1967 : */
1968 : /* seed: Apply seedMask to maskedSeed */
1969 0 : if ((ret = mgf_mask(buf + 1, hlen, buf + hlen + 1, ilen - hlen - 1,
1970 0 : (mbedtls_md_type_t) ctx->hash_id)) != 0 ||
1971 : /* DB: Apply dbMask to maskedDB */
1972 0 : (ret = mgf_mask(buf + hlen + 1, ilen - hlen - 1, buf + 1, hlen,
1973 0 : (mbedtls_md_type_t) ctx->hash_id)) != 0) {
1974 0 : goto cleanup;
1975 : }
1976 :
1977 : /* Generate lHash */
1978 0 : ret = compute_hash((mbedtls_md_type_t) ctx->hash_id,
1979 : label, label_len, lhash);
1980 0 : if (ret != 0) {
1981 0 : goto cleanup;
1982 : }
1983 :
1984 : /*
1985 : * Check contents, in "constant-time"
1986 : */
1987 0 : p = buf;
1988 :
1989 0 : bad = mbedtls_ct_bool(*p++); /* First byte must be 0 */
1990 :
1991 0 : p += hlen; /* Skip seed */
1992 :
1993 : /* Check lHash */
1994 0 : bad = mbedtls_ct_bool_or(bad, mbedtls_ct_bool(mbedtls_ct_memcmp(lhash, p, hlen)));
1995 0 : p += hlen;
1996 :
1997 : /* Get zero-padding len, but always read till end of buffer
1998 : * (minus one, for the 01 byte) */
1999 0 : pad_len = 0;
2000 0 : in_padding = MBEDTLS_CT_TRUE;
2001 0 : for (i = 0; i < ilen - 2 * hlen - 2; i++) {
2002 0 : in_padding = mbedtls_ct_bool_and(in_padding, mbedtls_ct_uint_eq(p[i], 0));
2003 0 : pad_len += mbedtls_ct_uint_if_else_0(in_padding, 1);
2004 : }
2005 :
2006 0 : p += pad_len;
2007 0 : bad = mbedtls_ct_bool_or(bad, mbedtls_ct_uint_ne(*p++, 0x01));
2008 :
2009 : /*
2010 : * The only information "leaked" is whether the padding was correct or not
2011 : * (eg, no data is copied if it was not correct). This meets the
2012 : * recommendations in PKCS#1 v2.2: an opponent cannot distinguish between
2013 : * the different error conditions.
2014 : */
2015 0 : if (bad != MBEDTLS_CT_FALSE) {
2016 0 : ret = MBEDTLS_ERR_RSA_INVALID_PADDING;
2017 0 : goto cleanup;
2018 : }
2019 :
2020 0 : if (ilen - ((size_t) (p - buf)) > output_max_len) {
2021 0 : ret = MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE;
2022 0 : goto cleanup;
2023 : }
2024 :
2025 0 : *olen = ilen - ((size_t) (p - buf));
2026 0 : if (*olen != 0) {
2027 0 : memcpy(output, p, *olen);
2028 : }
2029 0 : ret = 0;
2030 :
2031 0 : cleanup:
2032 0 : mbedtls_platform_zeroize(buf, sizeof(buf));
2033 0 : mbedtls_platform_zeroize(lhash, sizeof(lhash));
2034 :
2035 0 : return ret;
2036 : }
2037 : #endif /* MBEDTLS_PKCS1_V21 */
2038 :
2039 : #if defined(MBEDTLS_PKCS1_V15)
2040 : /*
2041 : * Implementation of the PKCS#1 v2.1 RSAES-PKCS1-V1_5-DECRYPT function
2042 : */
2043 0 : int mbedtls_rsa_rsaes_pkcs1_v15_decrypt(mbedtls_rsa_context *ctx,
2044 : int (*f_rng)(void *, unsigned char *, size_t),
2045 : void *p_rng,
2046 : size_t *olen,
2047 : const unsigned char *input,
2048 : unsigned char *output,
2049 : size_t output_max_len)
2050 : {
2051 0 : int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
2052 : size_t ilen;
2053 : unsigned char buf[MBEDTLS_MPI_MAX_SIZE];
2054 :
2055 0 : ilen = ctx->len;
2056 :
2057 0 : if (ctx->padding != MBEDTLS_RSA_PKCS_V15) {
2058 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
2059 : }
2060 :
2061 0 : if (ilen < 16 || ilen > sizeof(buf)) {
2062 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
2063 : }
2064 :
2065 0 : ret = mbedtls_rsa_private(ctx, f_rng, p_rng, input, buf);
2066 :
2067 0 : if (ret != 0) {
2068 0 : goto cleanup;
2069 : }
2070 :
2071 0 : ret = mbedtls_ct_rsaes_pkcs1_v15_unpadding(buf, ilen,
2072 : output, output_max_len, olen);
2073 :
2074 0 : cleanup:
2075 0 : mbedtls_platform_zeroize(buf, sizeof(buf));
2076 :
2077 0 : return ret;
2078 : }
2079 : #endif /* MBEDTLS_PKCS1_V15 */
2080 :
2081 : /*
2082 : * Do an RSA operation, then remove the message padding
2083 : */
2084 0 : int mbedtls_rsa_pkcs1_decrypt(mbedtls_rsa_context *ctx,
2085 : int (*f_rng)(void *, unsigned char *, size_t),
2086 : void *p_rng,
2087 : size_t *olen,
2088 : const unsigned char *input,
2089 : unsigned char *output,
2090 : size_t output_max_len)
2091 : {
2092 0 : switch (ctx->padding) {
2093 : #if defined(MBEDTLS_PKCS1_V15)
2094 0 : case MBEDTLS_RSA_PKCS_V15:
2095 0 : return mbedtls_rsa_rsaes_pkcs1_v15_decrypt(ctx, f_rng, p_rng, olen,
2096 : input, output, output_max_len);
2097 : #endif
2098 :
2099 : #if defined(MBEDTLS_PKCS1_V21)
2100 0 : case MBEDTLS_RSA_PKCS_V21:
2101 0 : return mbedtls_rsa_rsaes_oaep_decrypt(ctx, f_rng, p_rng, NULL, 0,
2102 : olen, input, output,
2103 : output_max_len);
2104 : #endif
2105 :
2106 0 : default:
2107 0 : return MBEDTLS_ERR_RSA_INVALID_PADDING;
2108 : }
2109 : }
2110 :
2111 : #if defined(MBEDTLS_PKCS1_V21)
2112 1 : static int rsa_rsassa_pss_sign_no_mode_check(mbedtls_rsa_context *ctx,
2113 : int (*f_rng)(void *, unsigned char *, size_t),
2114 : void *p_rng,
2115 : mbedtls_md_type_t md_alg,
2116 : unsigned int hashlen,
2117 : const unsigned char *hash,
2118 : int saltlen,
2119 : unsigned char *sig)
2120 : {
2121 : size_t olen;
2122 1 : unsigned char *p = sig;
2123 1 : unsigned char *salt = NULL;
2124 1 : size_t slen, min_slen, hlen, offset = 0;
2125 1 : int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
2126 : size_t msb;
2127 : mbedtls_md_type_t hash_id;
2128 :
2129 1 : if ((md_alg != MBEDTLS_MD_NONE || hashlen != 0) && hash == NULL) {
2130 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
2131 : }
2132 :
2133 1 : if (f_rng == NULL) {
2134 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
2135 : }
2136 :
2137 1 : olen = ctx->len;
2138 :
2139 1 : if (md_alg != MBEDTLS_MD_NONE) {
2140 : /* Gather length of hash to sign */
2141 1 : size_t exp_hashlen = mbedtls_md_get_size_from_type(md_alg);
2142 1 : if (exp_hashlen == 0) {
2143 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
2144 : }
2145 :
2146 1 : if (hashlen != exp_hashlen) {
2147 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
2148 : }
2149 : }
2150 :
2151 1 : hash_id = (mbedtls_md_type_t) ctx->hash_id;
2152 1 : if (hash_id == MBEDTLS_MD_NONE) {
2153 0 : hash_id = md_alg;
2154 : }
2155 1 : hlen = mbedtls_md_get_size_from_type(hash_id);
2156 1 : if (hlen == 0) {
2157 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
2158 : }
2159 :
2160 1 : if (saltlen == MBEDTLS_RSA_SALT_LEN_ANY) {
2161 : /* Calculate the largest possible salt length, up to the hash size.
2162 : * Normally this is the hash length, which is the maximum salt length
2163 : * according to FIPS 185-4 §5.5 (e) and common practice. If there is not
2164 : * enough room, use the maximum salt length that fits. The constraint is
2165 : * that the hash length plus the salt length plus 2 bytes must be at most
2166 : * the key length. This complies with FIPS 186-4 §5.5 (e) and RFC 8017
2167 : * (PKCS#1 v2.2) §9.1.1 step 3. */
2168 0 : min_slen = hlen - 2;
2169 0 : if (olen < hlen + min_slen + 2) {
2170 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
2171 0 : } else if (olen >= hlen + hlen + 2) {
2172 0 : slen = hlen;
2173 : } else {
2174 0 : slen = olen - hlen - 2;
2175 : }
2176 1 : } else if ((saltlen < 0) || (saltlen + hlen + 2 > olen)) {
2177 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
2178 : } else {
2179 1 : slen = (size_t) saltlen;
2180 : }
2181 :
2182 1 : memset(sig, 0, olen);
2183 :
2184 : /* Note: EMSA-PSS encoding is over the length of N - 1 bits */
2185 1 : msb = mbedtls_mpi_bitlen(&ctx->N) - 1;
2186 1 : p += olen - hlen - slen - 2;
2187 1 : *p++ = 0x01;
2188 :
2189 : /* Generate salt of length slen in place in the encoded message */
2190 1 : salt = p;
2191 1 : if ((ret = f_rng(p_rng, salt, slen)) != 0) {
2192 0 : return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_RSA_RNG_FAILED, ret);
2193 : }
2194 :
2195 1 : p += slen;
2196 :
2197 : /* Generate H = Hash( M' ) */
2198 1 : ret = hash_mprime(hash, hashlen, salt, slen, p, hash_id);
2199 1 : if (ret != 0) {
2200 0 : return ret;
2201 : }
2202 :
2203 : /* Compensate for boundary condition when applying mask */
2204 1 : if (msb % 8 == 0) {
2205 0 : offset = 1;
2206 : }
2207 :
2208 : /* maskedDB: Apply dbMask to DB */
2209 1 : ret = mgf_mask(sig + offset, olen - hlen - 1 - offset, p, hlen, hash_id);
2210 1 : if (ret != 0) {
2211 0 : return ret;
2212 : }
2213 :
2214 1 : msb = mbedtls_mpi_bitlen(&ctx->N) - 1;
2215 1 : sig[0] &= 0xFF >> (olen * 8 - msb);
2216 :
2217 1 : p += hlen;
2218 1 : *p++ = 0xBC;
2219 :
2220 1 : return mbedtls_rsa_private(ctx, f_rng, p_rng, sig, sig);
2221 : }
2222 :
2223 1 : static int rsa_rsassa_pss_sign(mbedtls_rsa_context *ctx,
2224 : int (*f_rng)(void *, unsigned char *, size_t),
2225 : void *p_rng,
2226 : mbedtls_md_type_t md_alg,
2227 : unsigned int hashlen,
2228 : const unsigned char *hash,
2229 : int saltlen,
2230 : unsigned char *sig)
2231 : {
2232 1 : if (ctx->padding != MBEDTLS_RSA_PKCS_V21) {
2233 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
2234 : }
2235 1 : if ((ctx->hash_id == MBEDTLS_MD_NONE) && (md_alg == MBEDTLS_MD_NONE)) {
2236 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
2237 : }
2238 1 : return rsa_rsassa_pss_sign_no_mode_check(ctx, f_rng, p_rng, md_alg, hashlen, hash, saltlen,
2239 : sig);
2240 : }
2241 :
2242 0 : int mbedtls_rsa_rsassa_pss_sign_no_mode_check(mbedtls_rsa_context *ctx,
2243 : int (*f_rng)(void *, unsigned char *, size_t),
2244 : void *p_rng,
2245 : mbedtls_md_type_t md_alg,
2246 : unsigned int hashlen,
2247 : const unsigned char *hash,
2248 : unsigned char *sig)
2249 : {
2250 0 : return rsa_rsassa_pss_sign_no_mode_check(ctx, f_rng, p_rng, md_alg,
2251 : hashlen, hash, MBEDTLS_RSA_SALT_LEN_ANY, sig);
2252 : }
2253 :
2254 : /*
2255 : * Implementation of the PKCS#1 v2.1 RSASSA-PSS-SIGN function with
2256 : * the option to pass in the salt length.
2257 : */
2258 1 : int mbedtls_rsa_rsassa_pss_sign_ext(mbedtls_rsa_context *ctx,
2259 : int (*f_rng)(void *, unsigned char *, size_t),
2260 : void *p_rng,
2261 : mbedtls_md_type_t md_alg,
2262 : unsigned int hashlen,
2263 : const unsigned char *hash,
2264 : int saltlen,
2265 : unsigned char *sig)
2266 : {
2267 1 : return rsa_rsassa_pss_sign(ctx, f_rng, p_rng, md_alg,
2268 : hashlen, hash, saltlen, sig);
2269 : }
2270 :
2271 : /*
2272 : * Implementation of the PKCS#1 v2.1 RSASSA-PSS-SIGN function
2273 : */
2274 0 : int mbedtls_rsa_rsassa_pss_sign(mbedtls_rsa_context *ctx,
2275 : int (*f_rng)(void *, unsigned char *, size_t),
2276 : void *p_rng,
2277 : mbedtls_md_type_t md_alg,
2278 : unsigned int hashlen,
2279 : const unsigned char *hash,
2280 : unsigned char *sig)
2281 : {
2282 0 : return rsa_rsassa_pss_sign(ctx, f_rng, p_rng, md_alg,
2283 : hashlen, hash, MBEDTLS_RSA_SALT_LEN_ANY, sig);
2284 : }
2285 : #endif /* MBEDTLS_PKCS1_V21 */
2286 :
2287 : #if defined(MBEDTLS_PKCS1_V15)
2288 : /*
2289 : * Implementation of the PKCS#1 v2.1 RSASSA-PKCS1-V1_5-SIGN function
2290 : */
2291 :
2292 : /* Construct a PKCS v1.5 encoding of a hashed message
2293 : *
2294 : * This is used both for signature generation and verification.
2295 : *
2296 : * Parameters:
2297 : * - md_alg: Identifies the hash algorithm used to generate the given hash;
2298 : * MBEDTLS_MD_NONE if raw data is signed.
2299 : * - hashlen: Length of hash. Must match md_alg if that's not NONE.
2300 : * - hash: Buffer containing the hashed message or the raw data.
2301 : * - dst_len: Length of the encoded message.
2302 : * - dst: Buffer to hold the encoded message.
2303 : *
2304 : * Assumptions:
2305 : * - hash has size hashlen.
2306 : * - dst points to a buffer of size at least dst_len.
2307 : *
2308 : */
2309 345 : static int rsa_rsassa_pkcs1_v15_encode(mbedtls_md_type_t md_alg,
2310 : unsigned int hashlen,
2311 : const unsigned char *hash,
2312 : size_t dst_len,
2313 : unsigned char *dst)
2314 : {
2315 345 : size_t oid_size = 0;
2316 345 : size_t nb_pad = dst_len;
2317 345 : unsigned char *p = dst;
2318 345 : const char *oid = NULL;
2319 :
2320 : /* Are we signing hashed or raw data? */
2321 345 : if (md_alg != MBEDTLS_MD_NONE) {
2322 345 : unsigned char md_size = mbedtls_md_get_size_from_type(md_alg);
2323 345 : if (md_size == 0) {
2324 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
2325 : }
2326 :
2327 345 : if (mbedtls_oid_get_oid_by_md(md_alg, &oid, &oid_size) != 0) {
2328 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
2329 : }
2330 :
2331 345 : if (hashlen != md_size) {
2332 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
2333 : }
2334 :
2335 : /* Double-check that 8 + hashlen + oid_size can be used as a
2336 : * 1-byte ASN.1 length encoding and that there's no overflow. */
2337 345 : if (8 + hashlen + oid_size >= 0x80 ||
2338 345 : 10 + hashlen < hashlen ||
2339 345 : 10 + hashlen + oid_size < 10 + hashlen) {
2340 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
2341 : }
2342 :
2343 : /*
2344 : * Static bounds check:
2345 : * - Need 10 bytes for five tag-length pairs.
2346 : * (Insist on 1-byte length encodings to protect against variants of
2347 : * Bleichenbacher's forgery attack against lax PKCS#1v1.5 verification)
2348 : * - Need hashlen bytes for hash
2349 : * - Need oid_size bytes for hash alg OID.
2350 : */
2351 345 : if (nb_pad < 10 + hashlen + oid_size) {
2352 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
2353 : }
2354 345 : nb_pad -= 10 + hashlen + oid_size;
2355 : } else {
2356 0 : if (nb_pad < hashlen) {
2357 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
2358 : }
2359 :
2360 0 : nb_pad -= hashlen;
2361 : }
2362 :
2363 : /* Need space for signature header and padding delimiter (3 bytes),
2364 : * and 8 bytes for the minimal padding */
2365 345 : if (nb_pad < 3 + 8) {
2366 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
2367 : }
2368 345 : nb_pad -= 3;
2369 :
2370 : /* Now nb_pad is the amount of memory to be filled
2371 : * with padding, and at least 8 bytes long. */
2372 :
2373 : /* Write signature header and padding */
2374 345 : *p++ = 0;
2375 345 : *p++ = MBEDTLS_RSA_SIGN;
2376 345 : memset(p, 0xFF, nb_pad);
2377 345 : p += nb_pad;
2378 345 : *p++ = 0;
2379 :
2380 : /* Are we signing raw data? */
2381 345 : if (md_alg == MBEDTLS_MD_NONE) {
2382 0 : memcpy(p, hash, hashlen);
2383 0 : return 0;
2384 : }
2385 :
2386 : /* Signing hashed data, add corresponding ASN.1 structure
2387 : *
2388 : * DigestInfo ::= SEQUENCE {
2389 : * digestAlgorithm DigestAlgorithmIdentifier,
2390 : * digest Digest }
2391 : * DigestAlgorithmIdentifier ::= AlgorithmIdentifier
2392 : * Digest ::= OCTET STRING
2393 : *
2394 : * Schematic:
2395 : * TAG-SEQ + LEN [ TAG-SEQ + LEN [ TAG-OID + LEN [ OID ]
2396 : * TAG-NULL + LEN [ NULL ] ]
2397 : * TAG-OCTET + LEN [ HASH ] ]
2398 : */
2399 345 : *p++ = MBEDTLS_ASN1_SEQUENCE | MBEDTLS_ASN1_CONSTRUCTED;
2400 345 : *p++ = (unsigned char) (0x08 + oid_size + hashlen);
2401 345 : *p++ = MBEDTLS_ASN1_SEQUENCE | MBEDTLS_ASN1_CONSTRUCTED;
2402 345 : *p++ = (unsigned char) (0x04 + oid_size);
2403 345 : *p++ = MBEDTLS_ASN1_OID;
2404 345 : *p++ = (unsigned char) oid_size;
2405 345 : memcpy(p, oid, oid_size);
2406 345 : p += oid_size;
2407 345 : *p++ = MBEDTLS_ASN1_NULL;
2408 345 : *p++ = 0x00;
2409 345 : *p++ = MBEDTLS_ASN1_OCTET_STRING;
2410 345 : *p++ = (unsigned char) hashlen;
2411 345 : memcpy(p, hash, hashlen);
2412 345 : p += hashlen;
2413 :
2414 : /* Just a sanity-check, should be automatic
2415 : * after the initial bounds check. */
2416 345 : if (p != dst + dst_len) {
2417 0 : mbedtls_platform_zeroize(dst, dst_len);
2418 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
2419 : }
2420 :
2421 345 : return 0;
2422 : }
2423 :
2424 : /*
2425 : * Do an RSA operation to sign the message digest
2426 : */
2427 37 : int mbedtls_rsa_rsassa_pkcs1_v15_sign(mbedtls_rsa_context *ctx,
2428 : int (*f_rng)(void *, unsigned char *, size_t),
2429 : void *p_rng,
2430 : mbedtls_md_type_t md_alg,
2431 : unsigned int hashlen,
2432 : const unsigned char *hash,
2433 : unsigned char *sig)
2434 : {
2435 37 : int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
2436 37 : unsigned char *sig_try = NULL, *verif = NULL;
2437 :
2438 37 : if ((md_alg != MBEDTLS_MD_NONE || hashlen != 0) && hash == NULL) {
2439 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
2440 : }
2441 :
2442 37 : if (ctx->padding != MBEDTLS_RSA_PKCS_V15) {
2443 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
2444 : }
2445 :
2446 : /*
2447 : * Prepare PKCS1-v1.5 encoding (padding and hash identifier)
2448 : */
2449 :
2450 37 : if ((ret = rsa_rsassa_pkcs1_v15_encode(md_alg, hashlen, hash,
2451 : ctx->len, sig)) != 0) {
2452 0 : return ret;
2453 : }
2454 :
2455 : /* Private key operation
2456 : *
2457 : * In order to prevent Lenstra's attack, make the signature in a
2458 : * temporary buffer and check it before returning it.
2459 : */
2460 :
2461 37 : sig_try = mbedtls_calloc(1, ctx->len);
2462 37 : if (sig_try == NULL) {
2463 0 : return MBEDTLS_ERR_MPI_ALLOC_FAILED;
2464 : }
2465 :
2466 37 : verif = mbedtls_calloc(1, ctx->len);
2467 37 : if (verif == NULL) {
2468 0 : mbedtls_free(sig_try);
2469 0 : return MBEDTLS_ERR_MPI_ALLOC_FAILED;
2470 : }
2471 :
2472 37 : MBEDTLS_MPI_CHK(mbedtls_rsa_private(ctx, f_rng, p_rng, sig, sig_try));
2473 37 : MBEDTLS_MPI_CHK(mbedtls_rsa_public(ctx, sig_try, verif));
2474 :
2475 37 : if (mbedtls_ct_memcmp(verif, sig, ctx->len) != 0) {
2476 0 : ret = MBEDTLS_ERR_RSA_PRIVATE_FAILED;
2477 0 : goto cleanup;
2478 : }
2479 :
2480 37 : memcpy(sig, sig_try, ctx->len);
2481 :
2482 37 : cleanup:
2483 37 : mbedtls_zeroize_and_free(sig_try, ctx->len);
2484 37 : mbedtls_zeroize_and_free(verif, ctx->len);
2485 :
2486 37 : if (ret != 0) {
2487 0 : memset(sig, '!', ctx->len);
2488 : }
2489 37 : return ret;
2490 : }
2491 : #endif /* MBEDTLS_PKCS1_V15 */
2492 :
2493 : /*
2494 : * Do an RSA operation to sign the message digest
2495 : */
2496 37 : int mbedtls_rsa_pkcs1_sign(mbedtls_rsa_context *ctx,
2497 : int (*f_rng)(void *, unsigned char *, size_t),
2498 : void *p_rng,
2499 : mbedtls_md_type_t md_alg,
2500 : unsigned int hashlen,
2501 : const unsigned char *hash,
2502 : unsigned char *sig)
2503 : {
2504 37 : if ((md_alg != MBEDTLS_MD_NONE || hashlen != 0) && hash == NULL) {
2505 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
2506 : }
2507 :
2508 37 : switch (ctx->padding) {
2509 : #if defined(MBEDTLS_PKCS1_V15)
2510 37 : case MBEDTLS_RSA_PKCS_V15:
2511 37 : return mbedtls_rsa_rsassa_pkcs1_v15_sign(ctx, f_rng, p_rng,
2512 : md_alg, hashlen, hash, sig);
2513 : #endif
2514 :
2515 : #if defined(MBEDTLS_PKCS1_V21)
2516 0 : case MBEDTLS_RSA_PKCS_V21:
2517 0 : return mbedtls_rsa_rsassa_pss_sign(ctx, f_rng, p_rng, md_alg,
2518 : hashlen, hash, sig);
2519 : #endif
2520 :
2521 0 : default:
2522 0 : return MBEDTLS_ERR_RSA_INVALID_PADDING;
2523 : }
2524 : }
2525 :
2526 : #if defined(MBEDTLS_PKCS1_V21)
2527 : /*
2528 : * Implementation of the PKCS#1 v2.1 RSASSA-PSS-VERIFY function
2529 : */
2530 1 : int mbedtls_rsa_rsassa_pss_verify_ext(mbedtls_rsa_context *ctx,
2531 : mbedtls_md_type_t md_alg,
2532 : unsigned int hashlen,
2533 : const unsigned char *hash,
2534 : mbedtls_md_type_t mgf1_hash_id,
2535 : int expected_salt_len,
2536 : const unsigned char *sig)
2537 : {
2538 1 : int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
2539 : size_t siglen;
2540 : unsigned char *p;
2541 : unsigned char *hash_start;
2542 : unsigned char result[MBEDTLS_MD_MAX_SIZE];
2543 : unsigned int hlen;
2544 : size_t observed_salt_len, msb;
2545 1 : unsigned char buf[MBEDTLS_MPI_MAX_SIZE] = { 0 };
2546 :
2547 1 : if ((md_alg != MBEDTLS_MD_NONE || hashlen != 0) && hash == NULL) {
2548 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
2549 : }
2550 :
2551 1 : siglen = ctx->len;
2552 :
2553 1 : if (siglen < 16 || siglen > sizeof(buf)) {
2554 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
2555 : }
2556 :
2557 1 : ret = mbedtls_rsa_public(ctx, sig, buf);
2558 :
2559 1 : if (ret != 0) {
2560 0 : return ret;
2561 : }
2562 :
2563 1 : p = buf;
2564 :
2565 1 : if (buf[siglen - 1] != 0xBC) {
2566 0 : return MBEDTLS_ERR_RSA_INVALID_PADDING;
2567 : }
2568 :
2569 1 : if (md_alg != MBEDTLS_MD_NONE) {
2570 : /* Gather length of hash to sign */
2571 1 : size_t exp_hashlen = mbedtls_md_get_size_from_type(md_alg);
2572 1 : if (exp_hashlen == 0) {
2573 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
2574 : }
2575 :
2576 1 : if (hashlen != exp_hashlen) {
2577 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
2578 : }
2579 : }
2580 :
2581 1 : hlen = mbedtls_md_get_size_from_type(mgf1_hash_id);
2582 1 : if (hlen == 0) {
2583 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
2584 : }
2585 :
2586 : /*
2587 : * Note: EMSA-PSS verification is over the length of N - 1 bits
2588 : */
2589 1 : msb = mbedtls_mpi_bitlen(&ctx->N) - 1;
2590 :
2591 1 : if (buf[0] >> (8 - siglen * 8 + msb)) {
2592 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
2593 : }
2594 :
2595 : /* Compensate for boundary condition when applying mask */
2596 1 : if (msb % 8 == 0) {
2597 0 : p++;
2598 0 : siglen -= 1;
2599 : }
2600 :
2601 1 : if (siglen < hlen + 2) {
2602 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
2603 : }
2604 1 : hash_start = p + siglen - hlen - 1;
2605 :
2606 1 : ret = mgf_mask(p, siglen - hlen - 1, hash_start, hlen, mgf1_hash_id);
2607 1 : if (ret != 0) {
2608 0 : return ret;
2609 : }
2610 :
2611 1 : buf[0] &= 0xFF >> (siglen * 8 - msb);
2612 :
2613 223 : while (p < hash_start - 1 && *p == 0) {
2614 222 : p++;
2615 : }
2616 :
2617 1 : if (*p++ != 0x01) {
2618 0 : return MBEDTLS_ERR_RSA_INVALID_PADDING;
2619 : }
2620 :
2621 1 : observed_salt_len = (size_t) (hash_start - p);
2622 :
2623 1 : if (expected_salt_len != MBEDTLS_RSA_SALT_LEN_ANY &&
2624 1 : observed_salt_len != (size_t) expected_salt_len) {
2625 0 : return MBEDTLS_ERR_RSA_INVALID_PADDING;
2626 : }
2627 :
2628 : /*
2629 : * Generate H = Hash( M' )
2630 : */
2631 1 : ret = hash_mprime(hash, hashlen, p, observed_salt_len,
2632 : result, mgf1_hash_id);
2633 1 : if (ret != 0) {
2634 0 : return ret;
2635 : }
2636 :
2637 1 : if (memcmp(hash_start, result, hlen) != 0) {
2638 0 : return MBEDTLS_ERR_RSA_VERIFY_FAILED;
2639 : }
2640 :
2641 1 : return 0;
2642 : }
2643 :
2644 : /*
2645 : * Simplified PKCS#1 v2.1 RSASSA-PSS-VERIFY function
2646 : */
2647 0 : int mbedtls_rsa_rsassa_pss_verify(mbedtls_rsa_context *ctx,
2648 : mbedtls_md_type_t md_alg,
2649 : unsigned int hashlen,
2650 : const unsigned char *hash,
2651 : const unsigned char *sig)
2652 : {
2653 : mbedtls_md_type_t mgf1_hash_id;
2654 0 : if ((md_alg != MBEDTLS_MD_NONE || hashlen != 0) && hash == NULL) {
2655 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
2656 : }
2657 :
2658 0 : mgf1_hash_id = (ctx->hash_id != MBEDTLS_MD_NONE)
2659 0 : ? (mbedtls_md_type_t) ctx->hash_id
2660 0 : : md_alg;
2661 :
2662 0 : return mbedtls_rsa_rsassa_pss_verify_ext(ctx,
2663 : md_alg, hashlen, hash,
2664 : mgf1_hash_id,
2665 : MBEDTLS_RSA_SALT_LEN_ANY,
2666 : sig);
2667 :
2668 : }
2669 : #endif /* MBEDTLS_PKCS1_V21 */
2670 :
2671 : #if defined(MBEDTLS_PKCS1_V15)
2672 : /*
2673 : * Implementation of the PKCS#1 v2.1 RSASSA-PKCS1-v1_5-VERIFY function
2674 : */
2675 308 : int mbedtls_rsa_rsassa_pkcs1_v15_verify(mbedtls_rsa_context *ctx,
2676 : mbedtls_md_type_t md_alg,
2677 : unsigned int hashlen,
2678 : const unsigned char *hash,
2679 : const unsigned char *sig)
2680 : {
2681 308 : int ret = 0;
2682 : size_t sig_len;
2683 308 : unsigned char *encoded = NULL, *encoded_expected = NULL;
2684 :
2685 308 : if ((md_alg != MBEDTLS_MD_NONE || hashlen != 0) && hash == NULL) {
2686 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
2687 : }
2688 :
2689 308 : sig_len = ctx->len;
2690 :
2691 : /*
2692 : * Prepare expected PKCS1 v1.5 encoding of hash.
2693 : */
2694 :
2695 616 : if ((encoded = mbedtls_calloc(1, sig_len)) == NULL ||
2696 308 : (encoded_expected = mbedtls_calloc(1, sig_len)) == NULL) {
2697 0 : ret = MBEDTLS_ERR_MPI_ALLOC_FAILED;
2698 0 : goto cleanup;
2699 : }
2700 :
2701 308 : if ((ret = rsa_rsassa_pkcs1_v15_encode(md_alg, hashlen, hash, sig_len,
2702 : encoded_expected)) != 0) {
2703 0 : goto cleanup;
2704 : }
2705 :
2706 : /*
2707 : * Apply RSA primitive to get what should be PKCS1 encoded hash.
2708 : */
2709 :
2710 308 : ret = mbedtls_rsa_public(ctx, sig, encoded);
2711 308 : if (ret != 0) {
2712 0 : goto cleanup;
2713 : }
2714 :
2715 : /*
2716 : * Compare
2717 : */
2718 :
2719 308 : if ((ret = mbedtls_ct_memcmp(encoded, encoded_expected,
2720 : sig_len)) != 0) {
2721 8 : ret = MBEDTLS_ERR_RSA_VERIFY_FAILED;
2722 8 : goto cleanup;
2723 : }
2724 :
2725 300 : cleanup:
2726 :
2727 308 : if (encoded != NULL) {
2728 308 : mbedtls_zeroize_and_free(encoded, sig_len);
2729 : }
2730 :
2731 308 : if (encoded_expected != NULL) {
2732 308 : mbedtls_zeroize_and_free(encoded_expected, sig_len);
2733 : }
2734 :
2735 308 : return ret;
2736 : }
2737 : #endif /* MBEDTLS_PKCS1_V15 */
2738 :
2739 : /*
2740 : * Do an RSA operation and check the message digest
2741 : */
2742 308 : int mbedtls_rsa_pkcs1_verify(mbedtls_rsa_context *ctx,
2743 : mbedtls_md_type_t md_alg,
2744 : unsigned int hashlen,
2745 : const unsigned char *hash,
2746 : const unsigned char *sig)
2747 : {
2748 308 : if ((md_alg != MBEDTLS_MD_NONE || hashlen != 0) && hash == NULL) {
2749 0 : return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
2750 : }
2751 :
2752 308 : switch (ctx->padding) {
2753 : #if defined(MBEDTLS_PKCS1_V15)
2754 308 : case MBEDTLS_RSA_PKCS_V15:
2755 308 : return mbedtls_rsa_rsassa_pkcs1_v15_verify(ctx, md_alg,
2756 : hashlen, hash, sig);
2757 : #endif
2758 :
2759 : #if defined(MBEDTLS_PKCS1_V21)
2760 0 : case MBEDTLS_RSA_PKCS_V21:
2761 0 : return mbedtls_rsa_rsassa_pss_verify(ctx, md_alg,
2762 : hashlen, hash, sig);
2763 : #endif
2764 :
2765 0 : default:
2766 0 : return MBEDTLS_ERR_RSA_INVALID_PADDING;
2767 : }
2768 : }
2769 :
2770 : /*
2771 : * Copy the components of an RSA key
2772 : */
2773 138 : int mbedtls_rsa_copy(mbedtls_rsa_context *dst, const mbedtls_rsa_context *src)
2774 : {
2775 138 : int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
2776 :
2777 138 : dst->len = src->len;
2778 :
2779 138 : MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&dst->N, &src->N));
2780 138 : MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&dst->E, &src->E));
2781 :
2782 138 : MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&dst->D, &src->D));
2783 138 : MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&dst->P, &src->P));
2784 138 : MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&dst->Q, &src->Q));
2785 :
2786 : #if !defined(MBEDTLS_RSA_NO_CRT)
2787 138 : MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&dst->DP, &src->DP));
2788 138 : MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&dst->DQ, &src->DQ));
2789 138 : MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&dst->QP, &src->QP));
2790 138 : MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&dst->RP, &src->RP));
2791 138 : MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&dst->RQ, &src->RQ));
2792 : #endif
2793 :
2794 138 : MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&dst->RN, &src->RN));
2795 :
2796 138 : MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&dst->Vi, &src->Vi));
2797 138 : MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&dst->Vf, &src->Vf));
2798 :
2799 138 : dst->padding = src->padding;
2800 138 : dst->hash_id = src->hash_id;
2801 :
2802 138 : cleanup:
2803 138 : if (ret != 0) {
2804 0 : mbedtls_rsa_free(dst);
2805 : }
2806 :
2807 138 : return ret;
2808 : }
2809 :
2810 : /*
2811 : * Free the components of an RSA key
2812 : */
2813 1465 : void mbedtls_rsa_free(mbedtls_rsa_context *ctx)
2814 : {
2815 1465 : if (ctx == NULL) {
2816 0 : return;
2817 : }
2818 :
2819 1465 : mbedtls_mpi_free(&ctx->Vi);
2820 1465 : mbedtls_mpi_free(&ctx->Vf);
2821 1465 : mbedtls_mpi_free(&ctx->RN);
2822 1465 : mbedtls_mpi_free(&ctx->D);
2823 1465 : mbedtls_mpi_free(&ctx->Q);
2824 1465 : mbedtls_mpi_free(&ctx->P);
2825 1465 : mbedtls_mpi_free(&ctx->E);
2826 1465 : mbedtls_mpi_free(&ctx->N);
2827 :
2828 : #if !defined(MBEDTLS_RSA_NO_CRT)
2829 1465 : mbedtls_mpi_free(&ctx->RQ);
2830 1465 : mbedtls_mpi_free(&ctx->RP);
2831 1465 : mbedtls_mpi_free(&ctx->QP);
2832 1465 : mbedtls_mpi_free(&ctx->DQ);
2833 1465 : mbedtls_mpi_free(&ctx->DP);
2834 : #endif /* MBEDTLS_RSA_NO_CRT */
2835 :
2836 : #if defined(MBEDTLS_THREADING_C)
2837 : /* Free the mutex, but only if it hasn't been freed already. */
2838 : if (ctx->ver != 0) {
2839 : mbedtls_mutex_free(&ctx->mutex);
2840 : ctx->ver = 0;
2841 : }
2842 : #endif
2843 : }
2844 :
2845 : #endif /* !MBEDTLS_RSA_ALT */
2846 :
2847 : #if defined(MBEDTLS_SELF_TEST)
2848 :
2849 :
2850 : /*
2851 : * Example RSA-1024 keypair, for test purposes
2852 : */
2853 : #define KEY_LEN 128
2854 :
2855 : #define RSA_N "9292758453063D803DD603D5E777D788" \
2856 : "8ED1D5BF35786190FA2F23EBC0848AEA" \
2857 : "DDA92CA6C3D80B32C4D109BE0F36D6AE" \
2858 : "7130B9CED7ACDF54CFC7555AC14EEBAB" \
2859 : "93A89813FBF3C4F8066D2D800F7C38A8" \
2860 : "1AE31942917403FF4946B0A83D3D3E05" \
2861 : "EE57C6F5F5606FB5D4BC6CD34EE0801A" \
2862 : "5E94BB77B07507233A0BC7BAC8F90F79"
2863 :
2864 : #define RSA_E "10001"
2865 :
2866 : #define RSA_D "24BF6185468786FDD303083D25E64EFC" \
2867 : "66CA472BC44D253102F8B4A9D3BFA750" \
2868 : "91386C0077937FE33FA3252D28855837" \
2869 : "AE1B484A8A9A45F7EE8C0C634F99E8CD" \
2870 : "DF79C5CE07EE72C7F123142198164234" \
2871 : "CABB724CF78B8173B9F880FC86322407" \
2872 : "AF1FEDFDDE2BEB674CA15F3E81A1521E" \
2873 : "071513A1E85B5DFA031F21ECAE91A34D"
2874 :
2875 : #define RSA_P "C36D0EB7FCD285223CFB5AABA5BDA3D8" \
2876 : "2C01CAD19EA484A87EA4377637E75500" \
2877 : "FCB2005C5C7DD6EC4AC023CDA285D796" \
2878 : "C3D9E75E1EFC42488BB4F1D13AC30A57"
2879 :
2880 : #define RSA_Q "C000DF51A7C77AE8D7C7370C1FF55B69" \
2881 : "E211C2B9E5DB1ED0BF61D0D9899620F4" \
2882 : "910E4168387E3C30AA1E00C339A79508" \
2883 : "8452DD96A9A5EA5D9DCA68DA636032AF"
2884 :
2885 : #define PT_LEN 24
2886 : #define RSA_PT "\xAA\xBB\xCC\x03\x02\x01\x00\xFF\xFF\xFF\xFF\xFF" \
2887 : "\x11\x22\x33\x0A\x0B\x0C\xCC\xDD\xDD\xDD\xDD\xDD"
2888 :
2889 : #if defined(MBEDTLS_PKCS1_V15)
2890 0 : static int myrand(void *rng_state, unsigned char *output, size_t len)
2891 : {
2892 : #if !defined(__OpenBSD__) && !defined(__NetBSD__)
2893 : size_t i;
2894 :
2895 0 : if (rng_state != NULL) {
2896 0 : rng_state = NULL;
2897 : }
2898 :
2899 0 : for (i = 0; i < len; ++i) {
2900 0 : output[i] = rand();
2901 : }
2902 : #else
2903 : if (rng_state != NULL) {
2904 : rng_state = NULL;
2905 : }
2906 :
2907 : arc4random_buf(output, len);
2908 : #endif /* !OpenBSD && !NetBSD */
2909 :
2910 0 : return 0;
2911 : }
2912 : #endif /* MBEDTLS_PKCS1_V15 */
2913 :
2914 : /*
2915 : * Checkup routine
2916 : */
2917 0 : int mbedtls_rsa_self_test(int verbose)
2918 : {
2919 0 : int ret = 0;
2920 : #if defined(MBEDTLS_PKCS1_V15)
2921 : size_t len;
2922 : mbedtls_rsa_context rsa;
2923 : unsigned char rsa_plaintext[PT_LEN];
2924 : unsigned char rsa_decrypted[PT_LEN];
2925 : unsigned char rsa_ciphertext[KEY_LEN];
2926 : #if defined(MBEDTLS_MD_CAN_SHA1)
2927 : unsigned char sha1sum[20];
2928 : #endif
2929 :
2930 : mbedtls_mpi K;
2931 :
2932 0 : mbedtls_mpi_init(&K);
2933 0 : mbedtls_rsa_init(&rsa);
2934 :
2935 0 : MBEDTLS_MPI_CHK(mbedtls_mpi_read_string(&K, 16, RSA_N));
2936 0 : MBEDTLS_MPI_CHK(mbedtls_rsa_import(&rsa, &K, NULL, NULL, NULL, NULL));
2937 0 : MBEDTLS_MPI_CHK(mbedtls_mpi_read_string(&K, 16, RSA_P));
2938 0 : MBEDTLS_MPI_CHK(mbedtls_rsa_import(&rsa, NULL, &K, NULL, NULL, NULL));
2939 0 : MBEDTLS_MPI_CHK(mbedtls_mpi_read_string(&K, 16, RSA_Q));
2940 0 : MBEDTLS_MPI_CHK(mbedtls_rsa_import(&rsa, NULL, NULL, &K, NULL, NULL));
2941 0 : MBEDTLS_MPI_CHK(mbedtls_mpi_read_string(&K, 16, RSA_D));
2942 0 : MBEDTLS_MPI_CHK(mbedtls_rsa_import(&rsa, NULL, NULL, NULL, &K, NULL));
2943 0 : MBEDTLS_MPI_CHK(mbedtls_mpi_read_string(&K, 16, RSA_E));
2944 0 : MBEDTLS_MPI_CHK(mbedtls_rsa_import(&rsa, NULL, NULL, NULL, NULL, &K));
2945 :
2946 0 : MBEDTLS_MPI_CHK(mbedtls_rsa_complete(&rsa));
2947 :
2948 0 : if (verbose != 0) {
2949 0 : mbedtls_printf(" RSA key validation: ");
2950 : }
2951 :
2952 0 : if (mbedtls_rsa_check_pubkey(&rsa) != 0 ||
2953 0 : mbedtls_rsa_check_privkey(&rsa) != 0) {
2954 0 : if (verbose != 0) {
2955 0 : mbedtls_printf("failed\n");
2956 : }
2957 :
2958 0 : ret = 1;
2959 0 : goto cleanup;
2960 : }
2961 :
2962 0 : if (verbose != 0) {
2963 0 : mbedtls_printf("passed\n PKCS#1 encryption : ");
2964 : }
2965 :
2966 0 : memcpy(rsa_plaintext, RSA_PT, PT_LEN);
2967 :
2968 0 : if (mbedtls_rsa_pkcs1_encrypt(&rsa, myrand, NULL,
2969 : PT_LEN, rsa_plaintext,
2970 : rsa_ciphertext) != 0) {
2971 0 : if (verbose != 0) {
2972 0 : mbedtls_printf("failed\n");
2973 : }
2974 :
2975 0 : ret = 1;
2976 0 : goto cleanup;
2977 : }
2978 :
2979 0 : if (verbose != 0) {
2980 0 : mbedtls_printf("passed\n PKCS#1 decryption : ");
2981 : }
2982 :
2983 0 : if (mbedtls_rsa_pkcs1_decrypt(&rsa, myrand, NULL,
2984 : &len, rsa_ciphertext, rsa_decrypted,
2985 : sizeof(rsa_decrypted)) != 0) {
2986 0 : if (verbose != 0) {
2987 0 : mbedtls_printf("failed\n");
2988 : }
2989 :
2990 0 : ret = 1;
2991 0 : goto cleanup;
2992 : }
2993 :
2994 0 : if (memcmp(rsa_decrypted, rsa_plaintext, len) != 0) {
2995 0 : if (verbose != 0) {
2996 0 : mbedtls_printf("failed\n");
2997 : }
2998 :
2999 0 : ret = 1;
3000 0 : goto cleanup;
3001 : }
3002 :
3003 0 : if (verbose != 0) {
3004 0 : mbedtls_printf("passed\n");
3005 : }
3006 :
3007 : #if defined(MBEDTLS_MD_CAN_SHA1)
3008 : if (verbose != 0) {
3009 : mbedtls_printf(" PKCS#1 data sign : ");
3010 : }
3011 :
3012 : if (mbedtls_md(mbedtls_md_info_from_type(MBEDTLS_MD_SHA1),
3013 : rsa_plaintext, PT_LEN, sha1sum) != 0) {
3014 : if (verbose != 0) {
3015 : mbedtls_printf("failed\n");
3016 : }
3017 :
3018 : return 1;
3019 : }
3020 :
3021 : if (mbedtls_rsa_pkcs1_sign(&rsa, myrand, NULL,
3022 : MBEDTLS_MD_SHA1, 20,
3023 : sha1sum, rsa_ciphertext) != 0) {
3024 : if (verbose != 0) {
3025 : mbedtls_printf("failed\n");
3026 : }
3027 :
3028 : ret = 1;
3029 : goto cleanup;
3030 : }
3031 :
3032 : if (verbose != 0) {
3033 : mbedtls_printf("passed\n PKCS#1 sig. verify: ");
3034 : }
3035 :
3036 : if (mbedtls_rsa_pkcs1_verify(&rsa, MBEDTLS_MD_SHA1, 20,
3037 : sha1sum, rsa_ciphertext) != 0) {
3038 : if (verbose != 0) {
3039 : mbedtls_printf("failed\n");
3040 : }
3041 :
3042 : ret = 1;
3043 : goto cleanup;
3044 : }
3045 :
3046 : if (verbose != 0) {
3047 : mbedtls_printf("passed\n");
3048 : }
3049 : #endif /* MBEDTLS_MD_CAN_SHA1 */
3050 :
3051 0 : if (verbose != 0) {
3052 0 : mbedtls_printf("\n");
3053 : }
3054 :
3055 0 : cleanup:
3056 0 : mbedtls_mpi_free(&K);
3057 0 : mbedtls_rsa_free(&rsa);
3058 : #else /* MBEDTLS_PKCS1_V15 */
3059 : ((void) verbose);
3060 : #endif /* MBEDTLS_PKCS1_V15 */
3061 0 : return ret;
3062 : }
3063 :
3064 : #endif /* MBEDTLS_SELF_TEST */
3065 :
3066 : #endif /* MBEDTLS_RSA_C */
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