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1 | /* | |
2 | * Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL project | |
3 | * 2006. | |
4 | */ | |
5 | /* ==================================================================== | |
6 | * Copyright (c) 2006 The OpenSSL Project. All rights reserved. | |
7 | * | |
8 | * Redistribution and use in source and binary forms, with or without | |
9 | * modification, are permitted provided that the following conditions | |
10 | * are met: | |
11 | * | |
12 | * 1. Redistributions of source code must retain the above copyright | |
13 | * notice, this list of conditions and the following disclaimer. | |
14 | * | |
15 | * 2. Redistributions in binary form must reproduce the above copyright | |
16 | * notice, this list of conditions and the following disclaimer in | |
17 | * the documentation and/or other materials provided with the | |
18 | * distribution. | |
19 | * | |
20 | * 3. All advertising materials mentioning features or use of this | |
21 | * software must display the following acknowledgment: | |
22 | * "This product includes software developed by the OpenSSL Project | |
23 | * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)" | |
24 | * | |
25 | * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to | |
26 | * endorse or promote products derived from this software without | |
27 | * prior written permission. For written permission, please contact | |
28 | * licensing@OpenSSL.org. | |
29 | * | |
30 | * 5. Products derived from this software may not be called "OpenSSL" | |
31 | * nor may "OpenSSL" appear in their names without prior written | |
32 | * permission of the OpenSSL Project. | |
33 | * | |
34 | * 6. Redistributions of any form whatsoever must retain the following | |
35 | * acknowledgment: | |
36 | * "This product includes software developed by the OpenSSL Project | |
37 | * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)" | |
38 | * | |
39 | * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY | |
40 | * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
41 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR | |
42 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR | |
43 | * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, | |
44 | * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |
45 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; | |
46 | * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
47 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, | |
48 | * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) | |
49 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED | |
50 | * OF THE POSSIBILITY OF SUCH DAMAGE. | |
51 | * ==================================================================== | |
52 | * | |
53 | * This product includes cryptographic software written by Eric Young | |
54 | * (eay@cryptsoft.com). This product includes software written by Tim | |
55 | * Hudson (tjh@cryptsoft.com). | |
56 | * | |
57 | */ | |
58 | ||
59 | #include <stdio.h> | |
60 | #include "cryptlib.h" | |
61 | #include <openssl/asn1t.h> | |
62 | #include <openssl/x509.h> | |
63 | #include <openssl/ec.h> | |
64 | #include "ec_lcl.h" | |
65 | #include <openssl/ecdsa.h> | |
66 | #include <openssl/evp.h> | |
67 | #include "internal/evp_int.h" | |
68 | ||
69 | /* EC pkey context structure */ | |
70 | ||
71 | typedef struct { | |
72 | /* Key and paramgen group */ | |
73 | EC_GROUP *gen_group; | |
74 | /* message digest */ | |
75 | const EVP_MD *md; | |
76 | /* Duplicate key if custom cofactor needed */ | |
77 | EC_KEY *co_key; | |
78 | /* Cofactor mode */ | |
79 | signed char cofactor_mode; | |
80 | /* KDF (if any) to use for ECDH */ | |
81 | char kdf_type; | |
82 | /* Message digest to use for key derivation */ | |
83 | const EVP_MD *kdf_md; | |
84 | /* User key material */ | |
85 | unsigned char *kdf_ukm; | |
86 | size_t kdf_ukmlen; | |
87 | /* KDF output length */ | |
88 | size_t kdf_outlen; | |
89 | } EC_PKEY_CTX; | |
90 | ||
91 | static int pkey_ec_init(EVP_PKEY_CTX *ctx) | |
92 | { | |
93 | EC_PKEY_CTX *dctx; | |
94 | ||
95 | dctx = OPENSSL_malloc(sizeof(*dctx)); | |
96 | if (!dctx) | |
97 | return 0; | |
98 | dctx->gen_group = NULL; | |
99 | dctx->md = NULL; | |
100 | ||
101 | dctx->cofactor_mode = -1; | |
102 | dctx->co_key = NULL; | |
103 | dctx->kdf_type = EVP_PKEY_ECDH_KDF_NONE; | |
104 | dctx->kdf_md = NULL; | |
105 | dctx->kdf_outlen = 0; | |
106 | dctx->kdf_ukm = NULL; | |
107 | dctx->kdf_ukmlen = 0; | |
108 | ||
109 | ctx->data = dctx; | |
110 | ||
111 | return 1; | |
112 | } | |
113 | ||
114 | static int pkey_ec_copy(EVP_PKEY_CTX *dst, EVP_PKEY_CTX *src) | |
115 | { | |
116 | EC_PKEY_CTX *dctx, *sctx; | |
117 | if (!pkey_ec_init(dst)) | |
118 | return 0; | |
119 | sctx = src->data; | |
120 | dctx = dst->data; | |
121 | if (sctx->gen_group) { | |
122 | dctx->gen_group = EC_GROUP_dup(sctx->gen_group); | |
123 | if (!dctx->gen_group) | |
124 | return 0; | |
125 | } | |
126 | dctx->md = sctx->md; | |
127 | ||
128 | if (sctx->co_key) { | |
129 | dctx->co_key = EC_KEY_dup(sctx->co_key); | |
130 | if (!dctx->co_key) | |
131 | return 0; | |
132 | } | |
133 | dctx->kdf_type = sctx->kdf_type; | |
134 | dctx->kdf_md = sctx->kdf_md; | |
135 | dctx->kdf_outlen = sctx->kdf_outlen; | |
136 | if (sctx->kdf_ukm) { | |
137 | dctx->kdf_ukm = BUF_memdup(sctx->kdf_ukm, sctx->kdf_ukmlen); | |
138 | if (!dctx->kdf_ukm) | |
139 | return 0; | |
140 | } else | |
141 | dctx->kdf_ukm = NULL; | |
142 | dctx->kdf_ukmlen = sctx->kdf_ukmlen; | |
143 | return 1; | |
144 | } | |
145 | ||
146 | static void pkey_ec_cleanup(EVP_PKEY_CTX *ctx) | |
147 | { | |
148 | EC_PKEY_CTX *dctx = ctx->data; | |
149 | if (dctx) { | |
150 | EC_GROUP_free(dctx->gen_group); | |
151 | EC_KEY_free(dctx->co_key); | |
152 | OPENSSL_free(dctx->kdf_ukm); | |
153 | OPENSSL_free(dctx); | |
154 | } | |
155 | } | |
156 | ||
157 | static int pkey_ec_sign(EVP_PKEY_CTX *ctx, unsigned char *sig, size_t *siglen, | |
158 | const unsigned char *tbs, size_t tbslen) | |
159 | { | |
160 | int ret, type; | |
161 | unsigned int sltmp; | |
162 | EC_PKEY_CTX *dctx = ctx->data; | |
163 | EC_KEY *ec = ctx->pkey->pkey.ec; | |
164 | ||
165 | if (!sig) { | |
166 | *siglen = ECDSA_size(ec); | |
167 | return 1; | |
168 | } else if (*siglen < (size_t)ECDSA_size(ec)) { | |
169 | ECerr(EC_F_PKEY_EC_SIGN, EC_R_BUFFER_TOO_SMALL); | |
170 | return 0; | |
171 | } | |
172 | ||
173 | if (dctx->md) | |
174 | type = EVP_MD_type(dctx->md); | |
175 | else | |
176 | type = NID_sha1; | |
177 | ||
178 | ret = ECDSA_sign(type, tbs, tbslen, sig, &sltmp, ec); | |
179 | ||
180 | if (ret <= 0) | |
181 | return ret; | |
182 | *siglen = (size_t)sltmp; | |
183 | return 1; | |
184 | } | |
185 | ||
186 | static int pkey_ec_verify(EVP_PKEY_CTX *ctx, | |
187 | const unsigned char *sig, size_t siglen, | |
188 | const unsigned char *tbs, size_t tbslen) | |
189 | { | |
190 | int ret, type; | |
191 | EC_PKEY_CTX *dctx = ctx->data; | |
192 | EC_KEY *ec = ctx->pkey->pkey.ec; | |
193 | ||
194 | if (dctx->md) | |
195 | type = EVP_MD_type(dctx->md); | |
196 | else | |
197 | type = NID_sha1; | |
198 | ||
199 | ret = ECDSA_verify(type, tbs, tbslen, sig, siglen, ec); | |
200 | ||
201 | return ret; | |
202 | } | |
203 | ||
204 | #ifndef OPENSSL_NO_EC | |
205 | static int pkey_ec_derive(EVP_PKEY_CTX *ctx, unsigned char *key, | |
206 | size_t *keylen) | |
207 | { | |
208 | int ret; | |
209 | size_t outlen; | |
210 | const EC_POINT *pubkey = NULL; | |
211 | EC_KEY *eckey; | |
212 | EC_PKEY_CTX *dctx = ctx->data; | |
213 | if (!ctx->pkey || !ctx->peerkey) { | |
214 | ECerr(EC_F_PKEY_EC_DERIVE, EC_R_KEYS_NOT_SET); | |
215 | return 0; | |
216 | } | |
217 | ||
218 | eckey = dctx->co_key ? dctx->co_key : ctx->pkey->pkey.ec; | |
219 | ||
220 | if (!key) { | |
221 | const EC_GROUP *group; | |
222 | group = EC_KEY_get0_group(eckey); | |
223 | *keylen = (EC_GROUP_get_degree(group) + 7) / 8; | |
224 | return 1; | |
225 | } | |
226 | pubkey = EC_KEY_get0_public_key(ctx->peerkey->pkey.ec); | |
227 | ||
228 | /* | |
229 | * NB: unlike PKCS#3 DH, if *outlen is less than maximum size this is not | |
230 | * an error, the result is truncated. | |
231 | */ | |
232 | ||
233 | outlen = *keylen; | |
234 | ||
235 | ret = ECDH_compute_key(key, outlen, pubkey, eckey, 0); | |
236 | if (ret <= 0) | |
237 | return 0; | |
238 | *keylen = ret; | |
239 | return 1; | |
240 | } | |
241 | ||
242 | static int pkey_ec_kdf_derive(EVP_PKEY_CTX *ctx, | |
243 | unsigned char *key, size_t *keylen) | |
244 | { | |
245 | EC_PKEY_CTX *dctx = ctx->data; | |
246 | unsigned char *ktmp = NULL; | |
247 | size_t ktmplen; | |
248 | int rv = 0; | |
249 | if (dctx->kdf_type == EVP_PKEY_ECDH_KDF_NONE) | |
250 | return pkey_ec_derive(ctx, key, keylen); | |
251 | if (!key) { | |
252 | *keylen = dctx->kdf_outlen; | |
253 | return 1; | |
254 | } | |
255 | if (*keylen != dctx->kdf_outlen) | |
256 | return 0; | |
257 | if (!pkey_ec_derive(ctx, NULL, &ktmplen)) | |
258 | return 0; | |
259 | ktmp = OPENSSL_malloc(ktmplen); | |
260 | if (!ktmp) | |
261 | return 0; | |
262 | if (!pkey_ec_derive(ctx, ktmp, &ktmplen)) | |
263 | goto err; | |
264 | /* Do KDF stuff */ | |
265 | if (!ECDH_KDF_X9_62(key, *keylen, ktmp, ktmplen, | |
266 | dctx->kdf_ukm, dctx->kdf_ukmlen, dctx->kdf_md)) | |
267 | goto err; | |
268 | rv = 1; | |
269 | ||
270 | err: | |
271 | OPENSSL_clear_free(ktmp, ktmplen); | |
272 | return rv; | |
273 | } | |
274 | #endif | |
275 | ||
276 | static int pkey_ec_ctrl(EVP_PKEY_CTX *ctx, int type, int p1, void *p2) | |
277 | { | |
278 | EC_PKEY_CTX *dctx = ctx->data; | |
279 | EC_GROUP *group; | |
280 | switch (type) { | |
281 | case EVP_PKEY_CTRL_EC_PARAMGEN_CURVE_NID: | |
282 | group = EC_GROUP_new_by_curve_name(p1); | |
283 | if (group == NULL) { | |
284 | ECerr(EC_F_PKEY_EC_CTRL, EC_R_INVALID_CURVE); | |
285 | return 0; | |
286 | } | |
287 | EC_GROUP_free(dctx->gen_group); | |
288 | dctx->gen_group = group; | |
289 | return 1; | |
290 | ||
291 | case EVP_PKEY_CTRL_EC_PARAM_ENC: | |
292 | if (!dctx->gen_group) { | |
293 | ECerr(EC_F_PKEY_EC_CTRL, EC_R_NO_PARAMETERS_SET); | |
294 | return 0; | |
295 | } | |
296 | EC_GROUP_set_asn1_flag(dctx->gen_group, p1); | |
297 | return 1; | |
298 | ||
299 | #ifndef OPENSSL_NO_EC | |
300 | case EVP_PKEY_CTRL_EC_ECDH_COFACTOR: | |
301 | if (p1 == -2) { | |
302 | if (dctx->cofactor_mode != -1) | |
303 | return dctx->cofactor_mode; | |
304 | else { | |
305 | EC_KEY *ec_key = ctx->pkey->pkey.ec; | |
306 | return EC_KEY_get_flags(ec_key) & EC_FLAG_COFACTOR_ECDH ? 1 : | |
307 | 0; | |
308 | } | |
309 | } else if (p1 < -1 || p1 > 1) | |
310 | return -2; | |
311 | dctx->cofactor_mode = p1; | |
312 | if (p1 != -1) { | |
313 | EC_KEY *ec_key = ctx->pkey->pkey.ec; | |
314 | if (!ec_key->group) | |
315 | return -2; | |
316 | /* If cofactor is 1 cofactor mode does nothing */ | |
317 | if (BN_is_one(ec_key->group->cofactor)) | |
318 | return 1; | |
319 | if (!dctx->co_key) { | |
320 | dctx->co_key = EC_KEY_dup(ec_key); | |
321 | if (!dctx->co_key) | |
322 | return 0; | |
323 | } | |
324 | if (p1) | |
325 | EC_KEY_set_flags(dctx->co_key, EC_FLAG_COFACTOR_ECDH); | |
326 | else | |
327 | EC_KEY_clear_flags(dctx->co_key, EC_FLAG_COFACTOR_ECDH); | |
328 | } else { | |
329 | EC_KEY_free(dctx->co_key); | |
330 | dctx->co_key = NULL; | |
331 | } | |
332 | return 1; | |
333 | #endif | |
334 | ||
335 | case EVP_PKEY_CTRL_EC_KDF_TYPE: | |
336 | if (p1 == -2) | |
337 | return dctx->kdf_type; | |
338 | if (p1 != EVP_PKEY_ECDH_KDF_NONE && p1 != EVP_PKEY_ECDH_KDF_X9_62) | |
339 | return -2; | |
340 | dctx->kdf_type = p1; | |
341 | return 1; | |
342 | ||
343 | case EVP_PKEY_CTRL_EC_KDF_MD: | |
344 | dctx->kdf_md = p2; | |
345 | return 1; | |
346 | ||
347 | case EVP_PKEY_CTRL_GET_EC_KDF_MD: | |
348 | *(const EVP_MD **)p2 = dctx->kdf_md; | |
349 | return 1; | |
350 | ||
351 | case EVP_PKEY_CTRL_EC_KDF_OUTLEN: | |
352 | if (p1 <= 0) | |
353 | return -2; | |
354 | dctx->kdf_outlen = (size_t)p1; | |
355 | return 1; | |
356 | ||
357 | case EVP_PKEY_CTRL_GET_EC_KDF_OUTLEN: | |
358 | *(int *)p2 = dctx->kdf_outlen; | |
359 | return 1; | |
360 | ||
361 | case EVP_PKEY_CTRL_EC_KDF_UKM: | |
362 | OPENSSL_free(dctx->kdf_ukm); | |
363 | dctx->kdf_ukm = p2; | |
364 | if (p2) | |
365 | dctx->kdf_ukmlen = p1; | |
366 | else | |
367 | dctx->kdf_ukmlen = 0; | |
368 | return 1; | |
369 | ||
370 | case EVP_PKEY_CTRL_GET_EC_KDF_UKM: | |
371 | *(unsigned char **)p2 = dctx->kdf_ukm; | |
372 | return dctx->kdf_ukmlen; | |
373 | ||
374 | case EVP_PKEY_CTRL_MD: | |
375 | if (EVP_MD_type((const EVP_MD *)p2) != NID_sha1 && | |
376 | EVP_MD_type((const EVP_MD *)p2) != NID_ecdsa_with_SHA1 && | |
377 | EVP_MD_type((const EVP_MD *)p2) != NID_sha224 && | |
378 | EVP_MD_type((const EVP_MD *)p2) != NID_sha256 && | |
379 | EVP_MD_type((const EVP_MD *)p2) != NID_sha384 && | |
380 | EVP_MD_type((const EVP_MD *)p2) != NID_sha512) { | |
381 | ECerr(EC_F_PKEY_EC_CTRL, EC_R_INVALID_DIGEST_TYPE); | |
382 | return 0; | |
383 | } | |
384 | dctx->md = p2; | |
385 | return 1; | |
386 | ||
387 | case EVP_PKEY_CTRL_GET_MD: | |
388 | *(const EVP_MD **)p2 = dctx->md; | |
389 | return 1; | |
390 | ||
391 | case EVP_PKEY_CTRL_PEER_KEY: | |
392 | /* Default behaviour is OK */ | |
393 | case EVP_PKEY_CTRL_DIGESTINIT: | |
394 | case EVP_PKEY_CTRL_PKCS7_SIGN: | |
395 | case EVP_PKEY_CTRL_CMS_SIGN: | |
396 | return 1; | |
397 | ||
398 | default: | |
399 | return -2; | |
400 | ||
401 | } | |
402 | } | |
403 | ||
404 | static int pkey_ec_ctrl_str(EVP_PKEY_CTX *ctx, | |
405 | const char *type, const char *value) | |
406 | { | |
407 | if (strcmp(type, "ec_paramgen_curve") == 0) { | |
408 | int nid; | |
409 | nid = EC_curve_nist2nid(value); | |
410 | if (nid == NID_undef) | |
411 | nid = OBJ_sn2nid(value); | |
412 | if (nid == NID_undef) | |
413 | nid = OBJ_ln2nid(value); | |
414 | if (nid == NID_undef) { | |
415 | ECerr(EC_F_PKEY_EC_CTRL_STR, EC_R_INVALID_CURVE); | |
416 | return 0; | |
417 | } | |
418 | return EVP_PKEY_CTX_set_ec_paramgen_curve_nid(ctx, nid); | |
419 | } else if (strcmp(type, "ec_param_enc") == 0) { | |
420 | int param_enc; | |
421 | if (strcmp(value, "explicit") == 0) | |
422 | param_enc = 0; | |
423 | else if (strcmp(value, "named_curve") == 0) | |
424 | param_enc = OPENSSL_EC_NAMED_CURVE; | |
425 | else | |
426 | return -2; | |
427 | return EVP_PKEY_CTX_set_ec_param_enc(ctx, param_enc); | |
428 | } else if (strcmp(type, "ecdh_kdf_md") == 0) { | |
429 | const EVP_MD *md; | |
430 | if (!(md = EVP_get_digestbyname(value))) { | |
431 | ECerr(EC_F_PKEY_EC_CTRL_STR, EC_R_INVALID_DIGEST); | |
432 | return 0; | |
433 | } | |
434 | return EVP_PKEY_CTX_set_ecdh_kdf_md(ctx, md); | |
435 | } else if (strcmp(type, "ecdh_cofactor_mode") == 0) { | |
436 | int co_mode; | |
437 | co_mode = atoi(value); | |
438 | return EVP_PKEY_CTX_set_ecdh_cofactor_mode(ctx, co_mode); | |
439 | } | |
440 | ||
441 | return -2; | |
442 | } | |
443 | ||
444 | static int pkey_ec_paramgen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey) | |
445 | { | |
446 | EC_KEY *ec = NULL; | |
447 | EC_PKEY_CTX *dctx = ctx->data; | |
448 | int ret = 0; | |
449 | if (dctx->gen_group == NULL) { | |
450 | ECerr(EC_F_PKEY_EC_PARAMGEN, EC_R_NO_PARAMETERS_SET); | |
451 | return 0; | |
452 | } | |
453 | ec = EC_KEY_new(); | |
454 | if (!ec) | |
455 | return 0; | |
456 | ret = EC_KEY_set_group(ec, dctx->gen_group); | |
457 | if (ret) | |
458 | EVP_PKEY_assign_EC_KEY(pkey, ec); | |
459 | else | |
460 | EC_KEY_free(ec); | |
461 | return ret; | |
462 | } | |
463 | ||
464 | static int pkey_ec_keygen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey) | |
465 | { | |
466 | EC_KEY *ec = NULL; | |
467 | EC_PKEY_CTX *dctx = ctx->data; | |
468 | if (ctx->pkey == NULL && dctx->gen_group == NULL) { | |
469 | ECerr(EC_F_PKEY_EC_KEYGEN, EC_R_NO_PARAMETERS_SET); | |
470 | return 0; | |
471 | } | |
472 | ec = EC_KEY_new(); | |
473 | if (!ec) | |
474 | return 0; | |
475 | EVP_PKEY_assign_EC_KEY(pkey, ec); | |
476 | if (ctx->pkey) { | |
477 | /* Note: if error return, pkey is freed by parent routine */ | |
478 | if (!EVP_PKEY_copy_parameters(pkey, ctx->pkey)) | |
479 | return 0; | |
480 | } else { | |
481 | if (!EC_KEY_set_group(ec, dctx->gen_group)) | |
482 | return 0; | |
483 | } | |
484 | return EC_KEY_generate_key(pkey->pkey.ec); | |
485 | } | |
486 | ||
487 | const EVP_PKEY_METHOD ec_pkey_meth = { | |
488 | EVP_PKEY_EC, | |
489 | 0, | |
490 | pkey_ec_init, | |
491 | pkey_ec_copy, | |
492 | pkey_ec_cleanup, | |
493 | ||
494 | 0, | |
495 | pkey_ec_paramgen, | |
496 | ||
497 | 0, | |
498 | pkey_ec_keygen, | |
499 | ||
500 | 0, | |
501 | pkey_ec_sign, | |
502 | ||
503 | 0, | |
504 | pkey_ec_verify, | |
505 | ||
506 | 0, 0, | |
507 | ||
508 | 0, 0, 0, 0, | |
509 | ||
510 | 0, 0, | |
511 | ||
512 | 0, 0, | |
513 | ||
514 | 0, | |
515 | #ifndef OPENSSL_NO_EC | |
516 | pkey_ec_kdf_derive, | |
517 | #else | |
518 | 0, | |
519 | #endif | |
520 | pkey_ec_ctrl, | |
521 | pkey_ec_ctrl_str | |
522 | }; |