1/*
2 * Copyright 2006-2018 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the Apache License 2.0 (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
8 */
9
10#include <stdio.h>
11#include "internal/cryptlib.h"
12#include <openssl/asn1t.h>
13#include <openssl/x509.h>
14#include <openssl/ec.h>
15#include "ec_local.h"
16#include <openssl/evp.h>
17#include "crypto/evp.h"
18
19/* EC pkey context structure */
20
21typedef struct {
22 /* Key and paramgen group */
23 EC_GROUP *gen_group;
24 /* message digest */
25 const EVP_MD *md;
26 /* Duplicate key if custom cofactor needed */
27 EC_KEY *co_key;
28 /* Cofactor mode */
29 signed char cofactor_mode;
30 /* KDF (if any) to use for ECDH */
31 char kdf_type;
32 /* Message digest to use for key derivation */
33 const EVP_MD *kdf_md;
34 /* User key material */
35 unsigned char *kdf_ukm;
36 size_t kdf_ukmlen;
37 /* KDF output length */
38 size_t kdf_outlen;
39} EC_PKEY_CTX;
40
41static int pkey_ec_init(EVP_PKEY_CTX *ctx)
42{
43 EC_PKEY_CTX *dctx;
44
45 if ((dctx = OPENSSL_zalloc(sizeof(*dctx))) == NULL) {
46 ECerr(EC_F_PKEY_EC_INIT, ERR_R_MALLOC_FAILURE);
47 return 0;
48 }
49
50 dctx->cofactor_mode = -1;
51 dctx->kdf_type = EVP_PKEY_ECDH_KDF_NONE;
52 ctx->data = dctx;
53 return 1;
54}
55
56static int pkey_ec_copy(EVP_PKEY_CTX *dst, const EVP_PKEY_CTX *src)
57{
58 EC_PKEY_CTX *dctx, *sctx;
59 if (!pkey_ec_init(dst))
60 return 0;
61 sctx = src->data;
62 dctx = dst->data;
63 if (sctx->gen_group) {
64 dctx->gen_group = EC_GROUP_dup(sctx->gen_group);
65 if (!dctx->gen_group)
66 return 0;
67 }
68 dctx->md = sctx->md;
69
70 if (sctx->co_key) {
71 dctx->co_key = EC_KEY_dup(sctx->co_key);
72 if (!dctx->co_key)
73 return 0;
74 }
75 dctx->kdf_type = sctx->kdf_type;
76 dctx->kdf_md = sctx->kdf_md;
77 dctx->kdf_outlen = sctx->kdf_outlen;
78 if (sctx->kdf_ukm) {
79 dctx->kdf_ukm = OPENSSL_memdup(sctx->kdf_ukm, sctx->kdf_ukmlen);
80 if (!dctx->kdf_ukm)
81 return 0;
82 } else
83 dctx->kdf_ukm = NULL;
84 dctx->kdf_ukmlen = sctx->kdf_ukmlen;
85 return 1;
86}
87
88static void pkey_ec_cleanup(EVP_PKEY_CTX *ctx)
89{
90 EC_PKEY_CTX *dctx = ctx->data;
91 if (dctx != NULL) {
92 EC_GROUP_free(dctx->gen_group);
93 EC_KEY_free(dctx->co_key);
94 OPENSSL_free(dctx->kdf_ukm);
95 OPENSSL_free(dctx);
96 ctx->data = NULL;
97 }
98}
99
100static int pkey_ec_sign(EVP_PKEY_CTX *ctx, unsigned char *sig, size_t *siglen,
101 const unsigned char *tbs, size_t tbslen)
102{
103 int ret, type;
104 unsigned int sltmp;
105 EC_PKEY_CTX *dctx = ctx->data;
106 EC_KEY *ec = ctx->pkey->pkey.ec;
107 const int sig_sz = ECDSA_size(ec);
108
109 /* ensure cast to size_t is safe */
110 if (!ossl_assert(sig_sz > 0))
111 return 0;
112
113 if (sig == NULL) {
114 *siglen = (size_t)sig_sz;
115 return 1;
116 }
117
118 if (*siglen < (size_t)sig_sz) {
119 ECerr(EC_F_PKEY_EC_SIGN, EC_R_BUFFER_TOO_SMALL);
120 return 0;
121 }
122
123 type = (dctx->md != NULL) ? EVP_MD_type(dctx->md) : NID_sha1;
124
125 ret = ECDSA_sign(type, tbs, tbslen, sig, &sltmp, ec);
126
127 if (ret <= 0)
128 return ret;
129 *siglen = (size_t)sltmp;
130 return 1;
131}
132
133static int pkey_ec_verify(EVP_PKEY_CTX *ctx,
134 const unsigned char *sig, size_t siglen,
135 const unsigned char *tbs, size_t tbslen)
136{
137 int ret, type;
138 EC_PKEY_CTX *dctx = ctx->data;
139 EC_KEY *ec = ctx->pkey->pkey.ec;
140
141 if (dctx->md)
142 type = EVP_MD_type(dctx->md);
143 else
144 type = NID_sha1;
145
146 ret = ECDSA_verify(type, tbs, tbslen, sig, siglen, ec);
147
148 return ret;
149}
150
151#ifndef OPENSSL_NO_EC
152static int pkey_ec_derive(EVP_PKEY_CTX *ctx, unsigned char *key, size_t *keylen)
153{
154 int ret;
155 size_t outlen;
156 const EC_POINT *pubkey = NULL;
157 EC_KEY *eckey;
158 EC_PKEY_CTX *dctx = ctx->data;
159 if (!ctx->pkey || !ctx->peerkey) {
160 ECerr(EC_F_PKEY_EC_DERIVE, EC_R_KEYS_NOT_SET);
161 return 0;
162 }
163
164 eckey = dctx->co_key ? dctx->co_key : ctx->pkey->pkey.ec;
165
166 if (!key) {
167 const EC_GROUP *group;
168 group = EC_KEY_get0_group(eckey);
169 *keylen = (EC_GROUP_get_degree(group) + 7) / 8;
170 return 1;
171 }
172 pubkey = EC_KEY_get0_public_key(ctx->peerkey->pkey.ec);
173
174 /*
175 * NB: unlike PKCS#3 DH, if *outlen is less than maximum size this is not
176 * an error, the result is truncated.
177 */
178
179 outlen = *keylen;
180
181 ret = ECDH_compute_key(key, outlen, pubkey, eckey, 0);
182 if (ret <= 0)
183 return 0;
184 *keylen = ret;
185 return 1;
186}
187
188static int pkey_ec_kdf_derive(EVP_PKEY_CTX *ctx,
189 unsigned char *key, size_t *keylen)
190{
191 EC_PKEY_CTX *dctx = ctx->data;
192 unsigned char *ktmp = NULL;
193 size_t ktmplen;
194 int rv = 0;
195 if (dctx->kdf_type == EVP_PKEY_ECDH_KDF_NONE)
196 return pkey_ec_derive(ctx, key, keylen);
197 if (!key) {
198 *keylen = dctx->kdf_outlen;
199 return 1;
200 }
201 if (*keylen != dctx->kdf_outlen)
202 return 0;
203 if (!pkey_ec_derive(ctx, NULL, &ktmplen))
204 return 0;
205 if ((ktmp = OPENSSL_malloc(ktmplen)) == NULL) {
206 ECerr(EC_F_PKEY_EC_KDF_DERIVE, ERR_R_MALLOC_FAILURE);
207 return 0;
208 }
209 if (!pkey_ec_derive(ctx, ktmp, &ktmplen))
210 goto err;
211 /* Do KDF stuff */
212 if (!ecdh_KDF_X9_63(key, *keylen, ktmp, ktmplen,
213 dctx->kdf_ukm, dctx->kdf_ukmlen, dctx->kdf_md))
214 goto err;
215 rv = 1;
216
217 err:
218 OPENSSL_clear_free(ktmp, ktmplen);
219 return rv;
220}
221#endif
222
223static int pkey_ec_ctrl(EVP_PKEY_CTX *ctx, int type, int p1, void *p2)
224{
225 EC_PKEY_CTX *dctx = ctx->data;
226 EC_GROUP *group;
227 switch (type) {
228 case EVP_PKEY_CTRL_EC_PARAMGEN_CURVE_NID:
229 group = EC_GROUP_new_by_curve_name(p1);
230 if (group == NULL) {
231 ECerr(EC_F_PKEY_EC_CTRL, EC_R_INVALID_CURVE);
232 return 0;
233 }
234 EC_GROUP_free(dctx->gen_group);
235 dctx->gen_group = group;
236 return 1;
237
238 case EVP_PKEY_CTRL_EC_PARAM_ENC:
239 if (!dctx->gen_group) {
240 ECerr(EC_F_PKEY_EC_CTRL, EC_R_NO_PARAMETERS_SET);
241 return 0;
242 }
243 EC_GROUP_set_asn1_flag(dctx->gen_group, p1);
244 return 1;
245
246#ifndef OPENSSL_NO_EC
247 case EVP_PKEY_CTRL_EC_ECDH_COFACTOR:
248 if (p1 == -2) {
249 if (dctx->cofactor_mode != -1)
250 return dctx->cofactor_mode;
251 else {
252 EC_KEY *ec_key = ctx->pkey->pkey.ec;
253 return EC_KEY_get_flags(ec_key) & EC_FLAG_COFACTOR_ECDH ? 1 : 0;
254 }
255 } else if (p1 < -1 || p1 > 1)
256 return -2;
257 dctx->cofactor_mode = p1;
258 if (p1 != -1) {
259 EC_KEY *ec_key = ctx->pkey->pkey.ec;
260 if (!ec_key->group)
261 return -2;
262 /* If cofactor is 1 cofactor mode does nothing */
263 if (BN_is_one(ec_key->group->cofactor))
264 return 1;
265 if (!dctx->co_key) {
266 dctx->co_key = EC_KEY_dup(ec_key);
267 if (!dctx->co_key)
268 return 0;
269 }
270 if (p1)
271 EC_KEY_set_flags(dctx->co_key, EC_FLAG_COFACTOR_ECDH);
272 else
273 EC_KEY_clear_flags(dctx->co_key, EC_FLAG_COFACTOR_ECDH);
274 } else {
275 EC_KEY_free(dctx->co_key);
276 dctx->co_key = NULL;
277 }
278 return 1;
279#endif
280
281 case EVP_PKEY_CTRL_EC_KDF_TYPE:
282 if (p1 == -2)
283 return dctx->kdf_type;
284 if (p1 != EVP_PKEY_ECDH_KDF_NONE && p1 != EVP_PKEY_ECDH_KDF_X9_63)
285 return -2;
286 dctx->kdf_type = p1;
287 return 1;
288
289 case EVP_PKEY_CTRL_EC_KDF_MD:
290 dctx->kdf_md = p2;
291 return 1;
292
293 case EVP_PKEY_CTRL_GET_EC_KDF_MD:
294 *(const EVP_MD **)p2 = dctx->kdf_md;
295 return 1;
296
297 case EVP_PKEY_CTRL_EC_KDF_OUTLEN:
298 if (p1 <= 0)
299 return -2;
300 dctx->kdf_outlen = (size_t)p1;
301 return 1;
302
303 case EVP_PKEY_CTRL_GET_EC_KDF_OUTLEN:
304 *(int *)p2 = dctx->kdf_outlen;
305 return 1;
306
307 case EVP_PKEY_CTRL_EC_KDF_UKM:
308 OPENSSL_free(dctx->kdf_ukm);
309 dctx->kdf_ukm = p2;
310 if (p2)
311 dctx->kdf_ukmlen = p1;
312 else
313 dctx->kdf_ukmlen = 0;
314 return 1;
315
316 case EVP_PKEY_CTRL_GET_EC_KDF_UKM:
317 *(unsigned char **)p2 = dctx->kdf_ukm;
318 return dctx->kdf_ukmlen;
319
320 case EVP_PKEY_CTRL_MD:
321 if (EVP_MD_type((const EVP_MD *)p2) != NID_sha1 &&
322 EVP_MD_type((const EVP_MD *)p2) != NID_ecdsa_with_SHA1 &&
323 EVP_MD_type((const EVP_MD *)p2) != NID_sha224 &&
324 EVP_MD_type((const EVP_MD *)p2) != NID_sha256 &&
325 EVP_MD_type((const EVP_MD *)p2) != NID_sha384 &&
326 EVP_MD_type((const EVP_MD *)p2) != NID_sha512 &&
327 EVP_MD_type((const EVP_MD *)p2) != NID_sha3_224 &&
328 EVP_MD_type((const EVP_MD *)p2) != NID_sha3_256 &&
329 EVP_MD_type((const EVP_MD *)p2) != NID_sha3_384 &&
330 EVP_MD_type((const EVP_MD *)p2) != NID_sha3_512 &&
331 EVP_MD_type((const EVP_MD *)p2) != NID_sm3) {
332 ECerr(EC_F_PKEY_EC_CTRL, EC_R_INVALID_DIGEST_TYPE);
333 return 0;
334 }
335 dctx->md = p2;
336 return 1;
337
338 case EVP_PKEY_CTRL_GET_MD:
339 *(const EVP_MD **)p2 = dctx->md;
340 return 1;
341
342 case EVP_PKEY_CTRL_PEER_KEY:
343 /* Default behaviour is OK */
344 case EVP_PKEY_CTRL_DIGESTINIT:
345 case EVP_PKEY_CTRL_PKCS7_SIGN:
346 case EVP_PKEY_CTRL_CMS_SIGN:
347 return 1;
348
349 default:
350 return -2;
351
352 }
353}
354
355static int pkey_ec_ctrl_str(EVP_PKEY_CTX *ctx,
356 const char *type, const char *value)
357{
358 if (strcmp(type, "ec_paramgen_curve") == 0) {
359 int nid;
360 nid = EC_curve_nist2nid(value);
361 if (nid == NID_undef)
362 nid = OBJ_sn2nid(value);
363 if (nid == NID_undef)
364 nid = OBJ_ln2nid(value);
365 if (nid == NID_undef) {
366 ECerr(EC_F_PKEY_EC_CTRL_STR, EC_R_INVALID_CURVE);
367 return 0;
368 }
369 return EVP_PKEY_CTX_set_ec_paramgen_curve_nid(ctx, nid);
370 } else if (strcmp(type, "ec_param_enc") == 0) {
371 int param_enc;
372 if (strcmp(value, "explicit") == 0)
373 param_enc = 0;
374 else if (strcmp(value, "named_curve") == 0)
375 param_enc = OPENSSL_EC_NAMED_CURVE;
376 else
377 return -2;
378 return EVP_PKEY_CTX_set_ec_param_enc(ctx, param_enc);
379 } else if (strcmp(type, "ecdh_kdf_md") == 0) {
380 const EVP_MD *md;
381 if ((md = EVP_get_digestbyname(value)) == NULL) {
382 ECerr(EC_F_PKEY_EC_CTRL_STR, EC_R_INVALID_DIGEST);
383 return 0;
384 }
385 return EVP_PKEY_CTX_set_ecdh_kdf_md(ctx, md);
386 } else if (strcmp(type, "ecdh_cofactor_mode") == 0) {
387 int co_mode;
388 co_mode = atoi(value);
389 return EVP_PKEY_CTX_set_ecdh_cofactor_mode(ctx, co_mode);
390 }
391
392 return -2;
393}
394
395static int pkey_ec_paramgen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey)
396{
397 EC_KEY *ec = NULL;
398 EC_PKEY_CTX *dctx = ctx->data;
399 int ret;
400
401 if (dctx->gen_group == NULL) {
402 ECerr(EC_F_PKEY_EC_PARAMGEN, EC_R_NO_PARAMETERS_SET);
403 return 0;
404 }
405 ec = EC_KEY_new();
406 if (ec == NULL)
407 return 0;
408 if (!(ret = EC_KEY_set_group(ec, dctx->gen_group))
409 || !ossl_assert(ret = EVP_PKEY_assign_EC_KEY(pkey, ec)))
410 EC_KEY_free(ec);
411 return ret;
412}
413
414static int pkey_ec_keygen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey)
415{
416 EC_KEY *ec = NULL;
417 EC_PKEY_CTX *dctx = ctx->data;
418 int ret;
419
420 if (ctx->pkey == NULL && dctx->gen_group == NULL) {
421 ECerr(EC_F_PKEY_EC_KEYGEN, EC_R_NO_PARAMETERS_SET);
422 return 0;
423 }
424 ec = EC_KEY_new();
425 if (ec == NULL)
426 return 0;
427 if (!ossl_assert(EVP_PKEY_assign_EC_KEY(pkey, ec))) {
428 EC_KEY_free(ec);
429 return 0;
430 }
431 /* Note: if error is returned, we count on caller to free pkey->pkey.ec */
432 if (ctx->pkey != NULL)
433 ret = EVP_PKEY_copy_parameters(pkey, ctx->pkey);
434 else
435 ret = EC_KEY_set_group(ec, dctx->gen_group);
436
437 return ret ? EC_KEY_generate_key(ec) : 0;
438}
439
440static const EVP_PKEY_METHOD ec_pkey_meth = {
441 EVP_PKEY_EC,
442 0,
443 pkey_ec_init,
444 pkey_ec_copy,
445 pkey_ec_cleanup,
446
447 0,
448 pkey_ec_paramgen,
449
450 0,
451 pkey_ec_keygen,
452
453 0,
454 pkey_ec_sign,
455
456 0,
457 pkey_ec_verify,
458
459 0, 0,
460
461 0, 0, 0, 0,
462
463 0,
464 0,
465
466 0,
467 0,
468
469 0,
470#ifndef OPENSSL_NO_EC
471 pkey_ec_kdf_derive,
472#else
473 0,
474#endif
475 pkey_ec_ctrl,
476 pkey_ec_ctrl_str
477};
478
479const EVP_PKEY_METHOD *ec_pkey_method(void)
480{
481 return &ec_pkey_meth;
482}
483