/src/mbedtls/library/dhm.c
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1 | | /* |
2 | | * Diffie-Hellman-Merkle key exchange |
3 | | * |
4 | | * Copyright The Mbed TLS Contributors |
5 | | * SPDX-License-Identifier: Apache-2.0 |
6 | | * |
7 | | * Licensed under the Apache License, Version 2.0 (the "License"); you may |
8 | | * not use this file except in compliance with the License. |
9 | | * You may obtain a copy of the License at |
10 | | * |
11 | | * http://www.apache.org/licenses/LICENSE-2.0 |
12 | | * |
13 | | * Unless required by applicable law or agreed to in writing, software |
14 | | * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT |
15 | | * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
16 | | * See the License for the specific language governing permissions and |
17 | | * limitations under the License. |
18 | | */ |
19 | | /* |
20 | | * The following sources were referenced in the design of this implementation |
21 | | * of the Diffie-Hellman-Merkle algorithm: |
22 | | * |
23 | | * [1] Handbook of Applied Cryptography - 1997, Chapter 12 |
24 | | * Menezes, van Oorschot and Vanstone |
25 | | * |
26 | | */ |
27 | | |
28 | | #include "common.h" |
29 | | |
30 | | #if defined(MBEDTLS_DHM_C) |
31 | | |
32 | | #include "mbedtls/dhm.h" |
33 | | #include "mbedtls/platform_util.h" |
34 | | #include "mbedtls/error.h" |
35 | | |
36 | | #include <string.h> |
37 | | |
38 | | #if defined(MBEDTLS_PEM_PARSE_C) |
39 | | #include "mbedtls/pem.h" |
40 | | #endif |
41 | | |
42 | | #if defined(MBEDTLS_ASN1_PARSE_C) |
43 | | #include "mbedtls/asn1.h" |
44 | | #endif |
45 | | |
46 | | #include "mbedtls/platform.h" |
47 | | |
48 | | #if !defined(MBEDTLS_DHM_ALT) |
49 | | |
50 | | /* |
51 | | * helper to validate the mbedtls_mpi size and import it |
52 | | */ |
53 | | static int dhm_read_bignum(mbedtls_mpi *X, |
54 | | unsigned char **p, |
55 | | const unsigned char *end) |
56 | 0 | { |
57 | 0 | int ret, n; |
58 | |
|
59 | 0 | if (end - *p < 2) { |
60 | 0 | return MBEDTLS_ERR_DHM_BAD_INPUT_DATA; |
61 | 0 | } |
62 | | |
63 | 0 | n = ((*p)[0] << 8) | (*p)[1]; |
64 | 0 | (*p) += 2; |
65 | |
|
66 | 0 | if ((int) (end - *p) < n) { |
67 | 0 | return MBEDTLS_ERR_DHM_BAD_INPUT_DATA; |
68 | 0 | } |
69 | | |
70 | 0 | if ((ret = mbedtls_mpi_read_binary(X, *p, n)) != 0) { |
71 | 0 | return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_DHM_READ_PARAMS_FAILED, ret); |
72 | 0 | } |
73 | | |
74 | 0 | (*p) += n; |
75 | |
|
76 | 0 | return 0; |
77 | 0 | } |
78 | | |
79 | | /* |
80 | | * Verify sanity of parameter with regards to P |
81 | | * |
82 | | * Parameter should be: 2 <= public_param <= P - 2 |
83 | | * |
84 | | * This means that we need to return an error if |
85 | | * public_param < 2 or public_param > P-2 |
86 | | * |
87 | | * For more information on the attack, see: |
88 | | * http://www.cl.cam.ac.uk/~rja14/Papers/psandqs.pdf |
89 | | * http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2005-2643 |
90 | | */ |
91 | | static int dhm_check_range(const mbedtls_mpi *param, const mbedtls_mpi *P) |
92 | 0 | { |
93 | 0 | mbedtls_mpi U; |
94 | 0 | int ret = 0; |
95 | |
|
96 | 0 | mbedtls_mpi_init(&U); |
97 | |
|
98 | 0 | MBEDTLS_MPI_CHK(mbedtls_mpi_sub_int(&U, P, 2)); |
99 | | |
100 | 0 | if (mbedtls_mpi_cmp_int(param, 2) < 0 || |
101 | 0 | mbedtls_mpi_cmp_mpi(param, &U) > 0) { |
102 | 0 | ret = MBEDTLS_ERR_DHM_BAD_INPUT_DATA; |
103 | 0 | } |
104 | |
|
105 | 0 | cleanup: |
106 | 0 | mbedtls_mpi_free(&U); |
107 | 0 | return ret; |
108 | 0 | } |
109 | | |
110 | | void mbedtls_dhm_init(mbedtls_dhm_context *ctx) |
111 | 1.12k | { |
112 | 1.12k | memset(ctx, 0, sizeof(mbedtls_dhm_context)); |
113 | 1.12k | } |
114 | | |
115 | | size_t mbedtls_dhm_get_bitlen(const mbedtls_dhm_context *ctx) |
116 | 0 | { |
117 | 0 | return mbedtls_mpi_bitlen(&ctx->P); |
118 | 0 | } |
119 | | |
120 | | size_t mbedtls_dhm_get_len(const mbedtls_dhm_context *ctx) |
121 | 0 | { |
122 | 0 | return mbedtls_mpi_size(&ctx->P); |
123 | 0 | } |
124 | | |
125 | | int mbedtls_dhm_get_value(const mbedtls_dhm_context *ctx, |
126 | | mbedtls_dhm_parameter param, |
127 | | mbedtls_mpi *dest) |
128 | 0 | { |
129 | 0 | const mbedtls_mpi *src = NULL; |
130 | 0 | switch (param) { |
131 | 0 | case MBEDTLS_DHM_PARAM_P: |
132 | 0 | src = &ctx->P; |
133 | 0 | break; |
134 | 0 | case MBEDTLS_DHM_PARAM_G: |
135 | 0 | src = &ctx->G; |
136 | 0 | break; |
137 | 0 | case MBEDTLS_DHM_PARAM_X: |
138 | 0 | src = &ctx->X; |
139 | 0 | break; |
140 | 0 | case MBEDTLS_DHM_PARAM_GX: |
141 | 0 | src = &ctx->GX; |
142 | 0 | break; |
143 | 0 | case MBEDTLS_DHM_PARAM_GY: |
144 | 0 | src = &ctx->GY; |
145 | 0 | break; |
146 | 0 | case MBEDTLS_DHM_PARAM_K: |
147 | 0 | src = &ctx->K; |
148 | 0 | break; |
149 | 0 | default: |
150 | 0 | return MBEDTLS_ERR_DHM_BAD_INPUT_DATA; |
151 | 0 | } |
152 | 0 | return mbedtls_mpi_copy(dest, src); |
153 | 0 | } |
154 | | |
155 | | /* |
156 | | * Parse the ServerKeyExchange parameters |
157 | | */ |
158 | | int mbedtls_dhm_read_params(mbedtls_dhm_context *ctx, |
159 | | unsigned char **p, |
160 | | const unsigned char *end) |
161 | 0 | { |
162 | 0 | int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
163 | |
|
164 | 0 | if ((ret = dhm_read_bignum(&ctx->P, p, end)) != 0 || |
165 | 0 | (ret = dhm_read_bignum(&ctx->G, p, end)) != 0 || |
166 | 0 | (ret = dhm_read_bignum(&ctx->GY, p, end)) != 0) { |
167 | 0 | return ret; |
168 | 0 | } |
169 | | |
170 | 0 | if ((ret = dhm_check_range(&ctx->GY, &ctx->P)) != 0) { |
171 | 0 | return ret; |
172 | 0 | } |
173 | | |
174 | 0 | return 0; |
175 | 0 | } |
176 | | |
177 | | /* |
178 | | * Pick a random R in the range [2, M-2] for blinding or key generation. |
179 | | */ |
180 | | static int dhm_random_below(mbedtls_mpi *R, const mbedtls_mpi *M, |
181 | | int (*f_rng)(void *, unsigned char *, size_t), void *p_rng) |
182 | 0 | { |
183 | 0 | int ret; |
184 | |
|
185 | 0 | MBEDTLS_MPI_CHK(mbedtls_mpi_random(R, 3, M, f_rng, p_rng)); |
186 | 0 | MBEDTLS_MPI_CHK(mbedtls_mpi_sub_int(R, R, 1)); |
187 | | |
188 | 0 | cleanup: |
189 | 0 | return ret; |
190 | 0 | } |
191 | | |
192 | | static int dhm_make_common(mbedtls_dhm_context *ctx, int x_size, |
193 | | int (*f_rng)(void *, unsigned char *, size_t), |
194 | | void *p_rng) |
195 | 0 | { |
196 | 0 | int ret = 0; |
197 | |
|
198 | 0 | if (mbedtls_mpi_cmp_int(&ctx->P, 0) == 0) { |
199 | 0 | return MBEDTLS_ERR_DHM_BAD_INPUT_DATA; |
200 | 0 | } |
201 | 0 | if (x_size < 0) { |
202 | 0 | return MBEDTLS_ERR_DHM_BAD_INPUT_DATA; |
203 | 0 | } |
204 | | |
205 | 0 | if ((unsigned) x_size < mbedtls_mpi_size(&ctx->P)) { |
206 | 0 | MBEDTLS_MPI_CHK(mbedtls_mpi_fill_random(&ctx->X, x_size, f_rng, p_rng)); |
207 | 0 | } else { |
208 | | /* Generate X as large as possible ( <= P - 2 ) */ |
209 | 0 | ret = dhm_random_below(&ctx->X, &ctx->P, f_rng, p_rng); |
210 | 0 | if (ret == MBEDTLS_ERR_MPI_NOT_ACCEPTABLE) { |
211 | 0 | return MBEDTLS_ERR_DHM_MAKE_PARAMS_FAILED; |
212 | 0 | } |
213 | 0 | if (ret != 0) { |
214 | 0 | return ret; |
215 | 0 | } |
216 | 0 | } |
217 | | |
218 | | /* |
219 | | * Calculate GX = G^X mod P |
220 | | */ |
221 | 0 | MBEDTLS_MPI_CHK(mbedtls_mpi_exp_mod(&ctx->GX, &ctx->G, &ctx->X, |
222 | 0 | &ctx->P, &ctx->RP)); |
223 | | |
224 | 0 | if ((ret = dhm_check_range(&ctx->GX, &ctx->P)) != 0) { |
225 | 0 | return ret; |
226 | 0 | } |
227 | | |
228 | 0 | cleanup: |
229 | 0 | return ret; |
230 | 0 | } |
231 | | |
232 | | /* |
233 | | * Setup and write the ServerKeyExchange parameters |
234 | | */ |
235 | | int mbedtls_dhm_make_params(mbedtls_dhm_context *ctx, int x_size, |
236 | | unsigned char *output, size_t *olen, |
237 | | int (*f_rng)(void *, unsigned char *, size_t), |
238 | | void *p_rng) |
239 | 0 | { |
240 | 0 | int ret; |
241 | 0 | size_t n1, n2, n3; |
242 | 0 | unsigned char *p; |
243 | |
|
244 | 0 | ret = dhm_make_common(ctx, x_size, f_rng, p_rng); |
245 | 0 | if (ret != 0) { |
246 | 0 | goto cleanup; |
247 | 0 | } |
248 | | |
249 | | /* |
250 | | * Export P, G, GX. RFC 5246 §4.4 states that "leading zero octets are |
251 | | * not required". We omit leading zeros for compactness. |
252 | | */ |
253 | 0 | #define DHM_MPI_EXPORT(X, n) \ |
254 | 0 | do { \ |
255 | 0 | MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary((X), \ |
256 | 0 | p + 2, \ |
257 | 0 | (n))); \ |
258 | 0 | *p++ = MBEDTLS_BYTE_1(n); \ |
259 | 0 | *p++ = MBEDTLS_BYTE_0(n); \ |
260 | 0 | p += (n); \ |
261 | 0 | } while (0) |
262 | | |
263 | 0 | n1 = mbedtls_mpi_size(&ctx->P); |
264 | 0 | n2 = mbedtls_mpi_size(&ctx->G); |
265 | 0 | n3 = mbedtls_mpi_size(&ctx->GX); |
266 | |
|
267 | 0 | p = output; |
268 | 0 | DHM_MPI_EXPORT(&ctx->P, n1); |
269 | 0 | DHM_MPI_EXPORT(&ctx->G, n2); |
270 | 0 | DHM_MPI_EXPORT(&ctx->GX, n3); |
271 | | |
272 | 0 | *olen = p - output; |
273 | |
|
274 | 0 | cleanup: |
275 | 0 | if (ret != 0 && ret > -128) { |
276 | 0 | ret = MBEDTLS_ERROR_ADD(MBEDTLS_ERR_DHM_MAKE_PARAMS_FAILED, ret); |
277 | 0 | } |
278 | 0 | return ret; |
279 | 0 | } |
280 | | |
281 | | /* |
282 | | * Set prime modulus and generator |
283 | | */ |
284 | | int mbedtls_dhm_set_group(mbedtls_dhm_context *ctx, |
285 | | const mbedtls_mpi *P, |
286 | | const mbedtls_mpi *G) |
287 | 0 | { |
288 | 0 | int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
289 | |
|
290 | 0 | if ((ret = mbedtls_mpi_copy(&ctx->P, P)) != 0 || |
291 | 0 | (ret = mbedtls_mpi_copy(&ctx->G, G)) != 0) { |
292 | 0 | return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_DHM_SET_GROUP_FAILED, ret); |
293 | 0 | } |
294 | | |
295 | 0 | return 0; |
296 | 0 | } |
297 | | |
298 | | /* |
299 | | * Import the peer's public value G^Y |
300 | | */ |
301 | | int mbedtls_dhm_read_public(mbedtls_dhm_context *ctx, |
302 | | const unsigned char *input, size_t ilen) |
303 | 0 | { |
304 | 0 | int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
305 | |
|
306 | 0 | if (ilen < 1 || ilen > mbedtls_dhm_get_len(ctx)) { |
307 | 0 | return MBEDTLS_ERR_DHM_BAD_INPUT_DATA; |
308 | 0 | } |
309 | | |
310 | 0 | if ((ret = mbedtls_mpi_read_binary(&ctx->GY, input, ilen)) != 0) { |
311 | 0 | return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_DHM_READ_PUBLIC_FAILED, ret); |
312 | 0 | } |
313 | | |
314 | 0 | return 0; |
315 | 0 | } |
316 | | |
317 | | /* |
318 | | * Create own private value X and export G^X |
319 | | */ |
320 | | int mbedtls_dhm_make_public(mbedtls_dhm_context *ctx, int x_size, |
321 | | unsigned char *output, size_t olen, |
322 | | int (*f_rng)(void *, unsigned char *, size_t), |
323 | | void *p_rng) |
324 | 0 | { |
325 | 0 | int ret; |
326 | |
|
327 | 0 | if (olen < 1 || olen > mbedtls_dhm_get_len(ctx)) { |
328 | 0 | return MBEDTLS_ERR_DHM_BAD_INPUT_DATA; |
329 | 0 | } |
330 | | |
331 | 0 | ret = dhm_make_common(ctx, x_size, f_rng, p_rng); |
332 | 0 | if (ret == MBEDTLS_ERR_DHM_MAKE_PARAMS_FAILED) { |
333 | 0 | return MBEDTLS_ERR_DHM_MAKE_PUBLIC_FAILED; |
334 | 0 | } |
335 | 0 | if (ret != 0) { |
336 | 0 | goto cleanup; |
337 | 0 | } |
338 | | |
339 | 0 | MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary(&ctx->GX, output, olen)); |
340 | | |
341 | 0 | cleanup: |
342 | 0 | if (ret != 0 && ret > -128) { |
343 | 0 | ret = MBEDTLS_ERROR_ADD(MBEDTLS_ERR_DHM_MAKE_PUBLIC_FAILED, ret); |
344 | 0 | } |
345 | 0 | return ret; |
346 | 0 | } |
347 | | |
348 | | |
349 | | /* |
350 | | * Use the blinding method and optimisation suggested in section 10 of: |
351 | | * KOCHER, Paul C. Timing attacks on implementations of Diffie-Hellman, RSA, |
352 | | * DSS, and other systems. In : Advances in Cryptology-CRYPTO'96. Springer |
353 | | * Berlin Heidelberg, 1996. p. 104-113. |
354 | | */ |
355 | | static int dhm_update_blinding(mbedtls_dhm_context *ctx, |
356 | | int (*f_rng)(void *, unsigned char *, size_t), void *p_rng) |
357 | 0 | { |
358 | 0 | int ret; |
359 | 0 | mbedtls_mpi R; |
360 | |
|
361 | 0 | mbedtls_mpi_init(&R); |
362 | | |
363 | | /* |
364 | | * Don't use any blinding the first time a particular X is used, |
365 | | * but remember it to use blinding next time. |
366 | | */ |
367 | 0 | if (mbedtls_mpi_cmp_mpi(&ctx->X, &ctx->pX) != 0) { |
368 | 0 | MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&ctx->pX, &ctx->X)); |
369 | 0 | MBEDTLS_MPI_CHK(mbedtls_mpi_lset(&ctx->Vi, 1)); |
370 | 0 | MBEDTLS_MPI_CHK(mbedtls_mpi_lset(&ctx->Vf, 1)); |
371 | | |
372 | 0 | return 0; |
373 | 0 | } |
374 | | |
375 | | /* |
376 | | * Ok, we need blinding. Can we re-use existing values? |
377 | | * If yes, just update them by squaring them. |
378 | | */ |
379 | 0 | if (mbedtls_mpi_cmp_int(&ctx->Vi, 1) != 0) { |
380 | 0 | MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&ctx->Vi, &ctx->Vi, &ctx->Vi)); |
381 | 0 | MBEDTLS_MPI_CHK(mbedtls_mpi_mod_mpi(&ctx->Vi, &ctx->Vi, &ctx->P)); |
382 | | |
383 | 0 | MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&ctx->Vf, &ctx->Vf, &ctx->Vf)); |
384 | 0 | MBEDTLS_MPI_CHK(mbedtls_mpi_mod_mpi(&ctx->Vf, &ctx->Vf, &ctx->P)); |
385 | | |
386 | 0 | return 0; |
387 | 0 | } |
388 | | |
389 | | /* |
390 | | * We need to generate blinding values from scratch |
391 | | */ |
392 | | |
393 | | /* Vi = random( 2, P-2 ) */ |
394 | 0 | MBEDTLS_MPI_CHK(dhm_random_below(&ctx->Vi, &ctx->P, f_rng, p_rng)); |
395 | | |
396 | | /* Vf = Vi^-X mod P |
397 | | * First compute Vi^-1 = R * (R Vi)^-1, (avoiding leaks from inv_mod), |
398 | | * then elevate to the Xth power. */ |
399 | 0 | MBEDTLS_MPI_CHK(dhm_random_below(&R, &ctx->P, f_rng, p_rng)); |
400 | 0 | MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&ctx->Vf, &ctx->Vi, &R)); |
401 | 0 | MBEDTLS_MPI_CHK(mbedtls_mpi_mod_mpi(&ctx->Vf, &ctx->Vf, &ctx->P)); |
402 | 0 | MBEDTLS_MPI_CHK(mbedtls_mpi_inv_mod(&ctx->Vf, &ctx->Vf, &ctx->P)); |
403 | 0 | MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&ctx->Vf, &ctx->Vf, &R)); |
404 | 0 | MBEDTLS_MPI_CHK(mbedtls_mpi_mod_mpi(&ctx->Vf, &ctx->Vf, &ctx->P)); |
405 | | |
406 | 0 | MBEDTLS_MPI_CHK(mbedtls_mpi_exp_mod(&ctx->Vf, &ctx->Vf, &ctx->X, &ctx->P, &ctx->RP)); |
407 | | |
408 | 0 | cleanup: |
409 | 0 | mbedtls_mpi_free(&R); |
410 | |
|
411 | 0 | return ret; |
412 | 0 | } |
413 | | |
414 | | /* |
415 | | * Derive and export the shared secret (G^Y)^X mod P |
416 | | */ |
417 | | int mbedtls_dhm_calc_secret(mbedtls_dhm_context *ctx, |
418 | | unsigned char *output, size_t output_size, size_t *olen, |
419 | | int (*f_rng)(void *, unsigned char *, size_t), |
420 | | void *p_rng) |
421 | 0 | { |
422 | 0 | int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
423 | 0 | mbedtls_mpi GYb; |
424 | |
|
425 | 0 | if (f_rng == NULL) { |
426 | 0 | return MBEDTLS_ERR_DHM_BAD_INPUT_DATA; |
427 | 0 | } |
428 | | |
429 | 0 | if (output_size < mbedtls_dhm_get_len(ctx)) { |
430 | 0 | return MBEDTLS_ERR_DHM_BAD_INPUT_DATA; |
431 | 0 | } |
432 | | |
433 | 0 | if ((ret = dhm_check_range(&ctx->GY, &ctx->P)) != 0) { |
434 | 0 | return ret; |
435 | 0 | } |
436 | | |
437 | 0 | mbedtls_mpi_init(&GYb); |
438 | | |
439 | | /* Blind peer's value */ |
440 | 0 | MBEDTLS_MPI_CHK(dhm_update_blinding(ctx, f_rng, p_rng)); |
441 | 0 | MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&GYb, &ctx->GY, &ctx->Vi)); |
442 | 0 | MBEDTLS_MPI_CHK(mbedtls_mpi_mod_mpi(&GYb, &GYb, &ctx->P)); |
443 | | |
444 | | /* Do modular exponentiation */ |
445 | 0 | MBEDTLS_MPI_CHK(mbedtls_mpi_exp_mod(&ctx->K, &GYb, &ctx->X, |
446 | 0 | &ctx->P, &ctx->RP)); |
447 | | |
448 | | /* Unblind secret value */ |
449 | 0 | MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&ctx->K, &ctx->K, &ctx->Vf)); |
450 | 0 | MBEDTLS_MPI_CHK(mbedtls_mpi_mod_mpi(&ctx->K, &ctx->K, &ctx->P)); |
451 | | |
452 | | /* Output the secret without any leading zero byte. This is mandatory |
453 | | * for TLS per RFC 5246 §8.1.2. */ |
454 | 0 | *olen = mbedtls_mpi_size(&ctx->K); |
455 | 0 | MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary(&ctx->K, output, *olen)); |
456 | | |
457 | 0 | cleanup: |
458 | 0 | mbedtls_mpi_free(&GYb); |
459 | |
|
460 | 0 | if (ret != 0) { |
461 | 0 | return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_DHM_CALC_SECRET_FAILED, ret); |
462 | 0 | } |
463 | | |
464 | 0 | return 0; |
465 | 0 | } |
466 | | |
467 | | /* |
468 | | * Free the components of a DHM key |
469 | | */ |
470 | | void mbedtls_dhm_free(mbedtls_dhm_context *ctx) |
471 | 1.12k | { |
472 | 1.12k | if (ctx == NULL) { |
473 | 0 | return; |
474 | 0 | } |
475 | | |
476 | 1.12k | mbedtls_mpi_free(&ctx->pX); |
477 | 1.12k | mbedtls_mpi_free(&ctx->Vf); |
478 | 1.12k | mbedtls_mpi_free(&ctx->Vi); |
479 | 1.12k | mbedtls_mpi_free(&ctx->RP); |
480 | 1.12k | mbedtls_mpi_free(&ctx->K); |
481 | 1.12k | mbedtls_mpi_free(&ctx->GY); |
482 | 1.12k | mbedtls_mpi_free(&ctx->GX); |
483 | 1.12k | mbedtls_mpi_free(&ctx->X); |
484 | 1.12k | mbedtls_mpi_free(&ctx->G); |
485 | 1.12k | mbedtls_mpi_free(&ctx->P); |
486 | | |
487 | 1.12k | mbedtls_platform_zeroize(ctx, sizeof(mbedtls_dhm_context)); |
488 | 1.12k | } |
489 | | |
490 | | #if defined(MBEDTLS_ASN1_PARSE_C) |
491 | | /* |
492 | | * Parse DHM parameters |
493 | | */ |
494 | | int mbedtls_dhm_parse_dhm(mbedtls_dhm_context *dhm, const unsigned char *dhmin, |
495 | | size_t dhminlen) |
496 | 0 | { |
497 | 0 | int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
498 | 0 | size_t len; |
499 | 0 | unsigned char *p, *end; |
500 | 0 | #if defined(MBEDTLS_PEM_PARSE_C) |
501 | 0 | mbedtls_pem_context pem; |
502 | 0 | #endif /* MBEDTLS_PEM_PARSE_C */ |
503 | |
|
504 | 0 | #if defined(MBEDTLS_PEM_PARSE_C) |
505 | 0 | mbedtls_pem_init(&pem); |
506 | | |
507 | | /* Avoid calling mbedtls_pem_read_buffer() on non-null-terminated string */ |
508 | 0 | if (dhminlen == 0 || dhmin[dhminlen - 1] != '\0') { |
509 | 0 | ret = MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT; |
510 | 0 | } else { |
511 | 0 | ret = mbedtls_pem_read_buffer(&pem, |
512 | 0 | "-----BEGIN DH PARAMETERS-----", |
513 | 0 | "-----END DH PARAMETERS-----", |
514 | 0 | dhmin, NULL, 0, &dhminlen); |
515 | 0 | } |
516 | |
|
517 | 0 | if (ret == 0) { |
518 | | /* |
519 | | * Was PEM encoded |
520 | | */ |
521 | 0 | dhminlen = pem.buflen; |
522 | 0 | } else if (ret != MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT) { |
523 | 0 | goto exit; |
524 | 0 | } |
525 | | |
526 | 0 | p = (ret == 0) ? pem.buf : (unsigned char *) dhmin; |
527 | | #else |
528 | | p = (unsigned char *) dhmin; |
529 | | #endif /* MBEDTLS_PEM_PARSE_C */ |
530 | 0 | end = p + dhminlen; |
531 | | |
532 | | /* |
533 | | * DHParams ::= SEQUENCE { |
534 | | * prime INTEGER, -- P |
535 | | * generator INTEGER, -- g |
536 | | * privateValueLength INTEGER OPTIONAL |
537 | | * } |
538 | | */ |
539 | 0 | if ((ret = mbedtls_asn1_get_tag(&p, end, &len, |
540 | 0 | MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) != 0) { |
541 | 0 | ret = MBEDTLS_ERROR_ADD(MBEDTLS_ERR_DHM_INVALID_FORMAT, ret); |
542 | 0 | goto exit; |
543 | 0 | } |
544 | | |
545 | 0 | end = p + len; |
546 | |
|
547 | 0 | if ((ret = mbedtls_asn1_get_mpi(&p, end, &dhm->P)) != 0 || |
548 | 0 | (ret = mbedtls_asn1_get_mpi(&p, end, &dhm->G)) != 0) { |
549 | 0 | ret = MBEDTLS_ERROR_ADD(MBEDTLS_ERR_DHM_INVALID_FORMAT, ret); |
550 | 0 | goto exit; |
551 | 0 | } |
552 | | |
553 | 0 | if (p != end) { |
554 | | /* This might be the optional privateValueLength. |
555 | | * If so, we can cleanly discard it */ |
556 | 0 | mbedtls_mpi rec; |
557 | 0 | mbedtls_mpi_init(&rec); |
558 | 0 | ret = mbedtls_asn1_get_mpi(&p, end, &rec); |
559 | 0 | mbedtls_mpi_free(&rec); |
560 | 0 | if (ret != 0) { |
561 | 0 | ret = MBEDTLS_ERROR_ADD(MBEDTLS_ERR_DHM_INVALID_FORMAT, ret); |
562 | 0 | goto exit; |
563 | 0 | } |
564 | 0 | if (p != end) { |
565 | 0 | ret = MBEDTLS_ERROR_ADD(MBEDTLS_ERR_DHM_INVALID_FORMAT, |
566 | 0 | MBEDTLS_ERR_ASN1_LENGTH_MISMATCH); |
567 | 0 | goto exit; |
568 | 0 | } |
569 | 0 | } |
570 | | |
571 | 0 | ret = 0; |
572 | |
|
573 | 0 | exit: |
574 | 0 | #if defined(MBEDTLS_PEM_PARSE_C) |
575 | 0 | mbedtls_pem_free(&pem); |
576 | 0 | #endif |
577 | 0 | if (ret != 0) { |
578 | 0 | mbedtls_dhm_free(dhm); |
579 | 0 | } |
580 | |
|
581 | 0 | return ret; |
582 | 0 | } |
583 | | |
584 | | #if defined(MBEDTLS_FS_IO) |
585 | | /* |
586 | | * Load all data from a file into a given buffer. |
587 | | * |
588 | | * The file is expected to contain either PEM or DER encoded data. |
589 | | * A terminating null byte is always appended. It is included in the announced |
590 | | * length only if the data looks like it is PEM encoded. |
591 | | */ |
592 | | static int load_file(const char *path, unsigned char **buf, size_t *n) |
593 | 0 | { |
594 | 0 | FILE *f; |
595 | 0 | long size; |
596 | |
|
597 | 0 | if ((f = fopen(path, "rb")) == NULL) { |
598 | 0 | return MBEDTLS_ERR_DHM_FILE_IO_ERROR; |
599 | 0 | } |
600 | | /* The data loaded here is public, so don't bother disabling buffering. */ |
601 | | |
602 | 0 | fseek(f, 0, SEEK_END); |
603 | 0 | if ((size = ftell(f)) == -1) { |
604 | 0 | fclose(f); |
605 | 0 | return MBEDTLS_ERR_DHM_FILE_IO_ERROR; |
606 | 0 | } |
607 | 0 | fseek(f, 0, SEEK_SET); |
608 | |
|
609 | 0 | *n = (size_t) size; |
610 | |
|
611 | 0 | if (*n + 1 == 0 || |
612 | 0 | (*buf = mbedtls_calloc(1, *n + 1)) == NULL) { |
613 | 0 | fclose(f); |
614 | 0 | return MBEDTLS_ERR_DHM_ALLOC_FAILED; |
615 | 0 | } |
616 | | |
617 | 0 | if (fread(*buf, 1, *n, f) != *n) { |
618 | 0 | fclose(f); |
619 | |
|
620 | 0 | mbedtls_platform_zeroize(*buf, *n + 1); |
621 | 0 | mbedtls_free(*buf); |
622 | |
|
623 | 0 | return MBEDTLS_ERR_DHM_FILE_IO_ERROR; |
624 | 0 | } |
625 | | |
626 | 0 | fclose(f); |
627 | |
|
628 | 0 | (*buf)[*n] = '\0'; |
629 | |
|
630 | 0 | if (strstr((const char *) *buf, "-----BEGIN ") != NULL) { |
631 | 0 | ++*n; |
632 | 0 | } |
633 | |
|
634 | 0 | return 0; |
635 | 0 | } |
636 | | |
637 | | /* |
638 | | * Load and parse DHM parameters |
639 | | */ |
640 | | int mbedtls_dhm_parse_dhmfile(mbedtls_dhm_context *dhm, const char *path) |
641 | 0 | { |
642 | 0 | int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
643 | 0 | size_t n; |
644 | 0 | unsigned char *buf; |
645 | |
|
646 | 0 | if ((ret = load_file(path, &buf, &n)) != 0) { |
647 | 0 | return ret; |
648 | 0 | } |
649 | | |
650 | 0 | ret = mbedtls_dhm_parse_dhm(dhm, buf, n); |
651 | |
|
652 | 0 | mbedtls_platform_zeroize(buf, n); |
653 | 0 | mbedtls_free(buf); |
654 | |
|
655 | 0 | return ret; |
656 | 0 | } |
657 | | #endif /* MBEDTLS_FS_IO */ |
658 | | #endif /* MBEDTLS_ASN1_PARSE_C */ |
659 | | #endif /* MBEDTLS_DHM_ALT */ |
660 | | |
661 | | #if defined(MBEDTLS_SELF_TEST) |
662 | | |
663 | | #if defined(MBEDTLS_PEM_PARSE_C) |
664 | | static const char mbedtls_test_dhm_params[] = |
665 | | "-----BEGIN DH PARAMETERS-----\r\n" |
666 | | "MIGHAoGBAJ419DBEOgmQTzo5qXl5fQcN9TN455wkOL7052HzxxRVMyhYmwQcgJvh\r\n" |
667 | | "1sa18fyfR9OiVEMYglOpkqVoGLN7qd5aQNNi5W7/C+VBdHTBJcGZJyyP5B3qcz32\r\n" |
668 | | "9mLJKudlVudV0Qxk5qUJaPZ/xupz0NyoVpviuiBOI1gNi8ovSXWzAgEC\r\n" |
669 | | "-----END DH PARAMETERS-----\r\n"; |
670 | | #else /* MBEDTLS_PEM_PARSE_C */ |
671 | | static const char mbedtls_test_dhm_params[] = { |
672 | | 0x30, 0x81, 0x87, 0x02, 0x81, 0x81, 0x00, 0x9e, 0x35, 0xf4, 0x30, 0x44, |
673 | | 0x3a, 0x09, 0x90, 0x4f, 0x3a, 0x39, 0xa9, 0x79, 0x79, 0x7d, 0x07, 0x0d, |
674 | | 0xf5, 0x33, 0x78, 0xe7, 0x9c, 0x24, 0x38, 0xbe, 0xf4, 0xe7, 0x61, 0xf3, |
675 | | 0xc7, 0x14, 0x55, 0x33, 0x28, 0x58, 0x9b, 0x04, 0x1c, 0x80, 0x9b, 0xe1, |
676 | | 0xd6, 0xc6, 0xb5, 0xf1, 0xfc, 0x9f, 0x47, 0xd3, 0xa2, 0x54, 0x43, 0x18, |
677 | | 0x82, 0x53, 0xa9, 0x92, 0xa5, 0x68, 0x18, 0xb3, 0x7b, 0xa9, 0xde, 0x5a, |
678 | | 0x40, 0xd3, 0x62, 0xe5, 0x6e, 0xff, 0x0b, 0xe5, 0x41, 0x74, 0x74, 0xc1, |
679 | | 0x25, 0xc1, 0x99, 0x27, 0x2c, 0x8f, 0xe4, 0x1d, 0xea, 0x73, 0x3d, 0xf6, |
680 | | 0xf6, 0x62, 0xc9, 0x2a, 0xe7, 0x65, 0x56, 0xe7, 0x55, 0xd1, 0x0c, 0x64, |
681 | | 0xe6, 0xa5, 0x09, 0x68, 0xf6, 0x7f, 0xc6, 0xea, 0x73, 0xd0, 0xdc, 0xa8, |
682 | | 0x56, 0x9b, 0xe2, 0xba, 0x20, 0x4e, 0x23, 0x58, 0x0d, 0x8b, 0xca, 0x2f, |
683 | | 0x49, 0x75, 0xb3, 0x02, 0x01, 0x02 |
684 | | }; |
685 | | #endif /* MBEDTLS_PEM_PARSE_C */ |
686 | | |
687 | | static const size_t mbedtls_test_dhm_params_len = sizeof(mbedtls_test_dhm_params); |
688 | | |
689 | | /* |
690 | | * Checkup routine |
691 | | */ |
692 | | int mbedtls_dhm_self_test(int verbose) |
693 | 0 | { |
694 | 0 | int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
695 | 0 | mbedtls_dhm_context dhm; |
696 | |
|
697 | 0 | mbedtls_dhm_init(&dhm); |
698 | |
|
699 | 0 | if (verbose != 0) { |
700 | 0 | mbedtls_printf(" DHM parameter load: "); |
701 | 0 | } |
702 | |
|
703 | 0 | if ((ret = mbedtls_dhm_parse_dhm(&dhm, |
704 | 0 | (const unsigned char *) mbedtls_test_dhm_params, |
705 | 0 | mbedtls_test_dhm_params_len)) != 0) { |
706 | 0 | if (verbose != 0) { |
707 | 0 | mbedtls_printf("failed\n"); |
708 | 0 | } |
709 | |
|
710 | 0 | ret = 1; |
711 | 0 | goto exit; |
712 | 0 | } |
713 | | |
714 | 0 | if (verbose != 0) { |
715 | 0 | mbedtls_printf("passed\n\n"); |
716 | 0 | } |
717 | |
|
718 | 0 | exit: |
719 | 0 | mbedtls_dhm_free(&dhm); |
720 | |
|
721 | 0 | return ret; |
722 | 0 | } |
723 | | |
724 | | #endif /* MBEDTLS_SELF_TEST */ |
725 | | |
726 | | #endif /* MBEDTLS_DHM_C */ |