1 /*
2 * Copyright 2006-2021 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 /*
11 * ECDH and ECDSA low level APIs are deprecated for public use, but still ok
12 * for internal use.
13 */
14 #include "internal/deprecated.h"
15
16 #include <stdio.h>
17 #include "internal/cryptlib.h"
18 #include <openssl/asn1t.h>
19 #include <openssl/x509.h>
20 #include <openssl/ec.h>
21 #include "ec_local.h"
22 #include <openssl/evp.h>
23 #include "crypto/evp.h"
24
25 /* EC pkey context structure */
26
27 typedef struct {
28 /* Key and paramgen group */
29 EC_GROUP *gen_group;
30 /* message digest */
31 const EVP_MD *md;
32 /* Duplicate key if custom cofactor needed */
33 EC_KEY *co_key;
34 /* Cofactor mode */
35 signed char cofactor_mode;
36 /* KDF (if any) to use for ECDH */
37 char kdf_type;
38 /* Message digest to use for key derivation */
39 const EVP_MD *kdf_md;
40 /* User key material */
41 unsigned char *kdf_ukm;
42 size_t kdf_ukmlen;
43 /* KDF output length */
44 size_t kdf_outlen;
45 } EC_PKEY_CTX;
46
pkey_ec_init(EVP_PKEY_CTX * ctx)47 static int pkey_ec_init(EVP_PKEY_CTX *ctx)
48 {
49 EC_PKEY_CTX *dctx;
50
51 if ((dctx = OPENSSL_zalloc(sizeof(*dctx))) == NULL) {
52 ERR_raise(ERR_LIB_EC, ERR_R_MALLOC_FAILURE);
53 return 0;
54 }
55
56 dctx->cofactor_mode = -1;
57 dctx->kdf_type = EVP_PKEY_ECDH_KDF_NONE;
58 ctx->data = dctx;
59 return 1;
60 }
61
pkey_ec_copy(EVP_PKEY_CTX * dst,const EVP_PKEY_CTX * src)62 static int pkey_ec_copy(EVP_PKEY_CTX *dst, const EVP_PKEY_CTX *src)
63 {
64 EC_PKEY_CTX *dctx, *sctx;
65 if (!pkey_ec_init(dst))
66 return 0;
67 sctx = src->data;
68 dctx = dst->data;
69 if (sctx->gen_group) {
70 dctx->gen_group = EC_GROUP_dup(sctx->gen_group);
71 if (!dctx->gen_group)
72 return 0;
73 }
74 dctx->md = sctx->md;
75
76 if (sctx->co_key) {
77 dctx->co_key = EC_KEY_dup(sctx->co_key);
78 if (!dctx->co_key)
79 return 0;
80 }
81 dctx->kdf_type = sctx->kdf_type;
82 dctx->kdf_md = sctx->kdf_md;
83 dctx->kdf_outlen = sctx->kdf_outlen;
84 if (sctx->kdf_ukm) {
85 dctx->kdf_ukm = OPENSSL_memdup(sctx->kdf_ukm, sctx->kdf_ukmlen);
86 if (!dctx->kdf_ukm)
87 return 0;
88 } else
89 dctx->kdf_ukm = NULL;
90 dctx->kdf_ukmlen = sctx->kdf_ukmlen;
91 return 1;
92 }
93
pkey_ec_cleanup(EVP_PKEY_CTX * ctx)94 static void pkey_ec_cleanup(EVP_PKEY_CTX *ctx)
95 {
96 EC_PKEY_CTX *dctx = ctx->data;
97 if (dctx != NULL) {
98 EC_GROUP_free(dctx->gen_group);
99 EC_KEY_free(dctx->co_key);
100 OPENSSL_free(dctx->kdf_ukm);
101 OPENSSL_free(dctx);
102 ctx->data = NULL;
103 }
104 }
105
pkey_ec_sign(EVP_PKEY_CTX * ctx,unsigned char * sig,size_t * siglen,const unsigned char * tbs,size_t tbslen)106 static int pkey_ec_sign(EVP_PKEY_CTX *ctx, unsigned char *sig, size_t *siglen,
107 const unsigned char *tbs, size_t tbslen)
108 {
109 int ret, type;
110 unsigned int sltmp;
111 EC_PKEY_CTX *dctx = ctx->data;
112 /*
113 * Discard const. Its marked as const because this may be a cached copy of
114 * the "real" key. These calls don't make any modifications that need to
115 * be reflected back in the "original" key.
116 */
117 EC_KEY *ec = (EC_KEY *)EVP_PKEY_get0_EC_KEY(ctx->pkey);
118 const int sig_sz = ECDSA_size(ec);
119
120 /* ensure cast to size_t is safe */
121 if (!ossl_assert(sig_sz > 0))
122 return 0;
123
124 if (sig == NULL) {
125 *siglen = (size_t)sig_sz;
126 return 1;
127 }
128
129 if (*siglen < (size_t)sig_sz) {
130 ERR_raise(ERR_LIB_EC, EC_R_BUFFER_TOO_SMALL);
131 return 0;
132 }
133
134 type = (dctx->md != NULL) ? EVP_MD_get_type(dctx->md) : NID_sha1;
135
136 ret = ECDSA_sign(type, tbs, tbslen, sig, &sltmp, ec);
137
138 if (ret <= 0)
139 return ret;
140 *siglen = (size_t)sltmp;
141 return 1;
142 }
143
pkey_ec_verify(EVP_PKEY_CTX * ctx,const unsigned char * sig,size_t siglen,const unsigned char * tbs,size_t tbslen)144 static int pkey_ec_verify(EVP_PKEY_CTX *ctx,
145 const unsigned char *sig, size_t siglen,
146 const unsigned char *tbs, size_t tbslen)
147 {
148 int ret, type;
149 EC_PKEY_CTX *dctx = ctx->data;
150 /*
151 * Discard const. Its marked as const because this may be a cached copy of
152 * the "real" key. These calls don't make any modifications that need to
153 * be reflected back in the "original" key.
154 */
155 EC_KEY *ec = (EC_KEY *)EVP_PKEY_get0_EC_KEY(ctx->pkey);
156
157 if (dctx->md)
158 type = EVP_MD_get_type(dctx->md);
159 else
160 type = NID_sha1;
161
162 ret = ECDSA_verify(type, tbs, tbslen, sig, siglen, ec);
163
164 return ret;
165 }
166
167 #ifndef OPENSSL_NO_EC
pkey_ec_derive(EVP_PKEY_CTX * ctx,unsigned char * key,size_t * keylen)168 static int pkey_ec_derive(EVP_PKEY_CTX *ctx, unsigned char *key, size_t *keylen)
169 {
170 int ret;
171 size_t outlen;
172 const EC_POINT *pubkey = NULL;
173 EC_KEY *eckey;
174 const EC_KEY *eckeypub;
175 EC_PKEY_CTX *dctx = ctx->data;
176
177 if (ctx->pkey == NULL || ctx->peerkey == NULL) {
178 ERR_raise(ERR_LIB_EC, EC_R_KEYS_NOT_SET);
179 return 0;
180 }
181 eckeypub = EVP_PKEY_get0_EC_KEY(ctx->peerkey);
182 if (eckeypub == NULL) {
183 ERR_raise(ERR_LIB_EC, EC_R_KEYS_NOT_SET);
184 return 0;
185 }
186
187 eckey = dctx->co_key ? dctx->co_key
188 : (EC_KEY *)EVP_PKEY_get0_EC_KEY(ctx->pkey);
189
190 if (!key) {
191 const EC_GROUP *group;
192 group = EC_KEY_get0_group(eckey);
193
194 if (group == NULL)
195 return 0;
196 *keylen = (EC_GROUP_get_degree(group) + 7) / 8;
197 return 1;
198 }
199 pubkey = EC_KEY_get0_public_key(eckeypub);
200
201 /*
202 * NB: unlike PKCS#3 DH, if *outlen is less than maximum size this is not
203 * an error, the result is truncated.
204 */
205
206 outlen = *keylen;
207
208 ret = ECDH_compute_key(key, outlen, pubkey, eckey, 0);
209 if (ret <= 0)
210 return 0;
211 *keylen = ret;
212 return 1;
213 }
214
pkey_ec_kdf_derive(EVP_PKEY_CTX * ctx,unsigned char * key,size_t * keylen)215 static int pkey_ec_kdf_derive(EVP_PKEY_CTX *ctx,
216 unsigned char *key, size_t *keylen)
217 {
218 EC_PKEY_CTX *dctx = ctx->data;
219 unsigned char *ktmp = NULL;
220 size_t ktmplen;
221 int rv = 0;
222 if (dctx->kdf_type == EVP_PKEY_ECDH_KDF_NONE)
223 return pkey_ec_derive(ctx, key, keylen);
224 if (!key) {
225 *keylen = dctx->kdf_outlen;
226 return 1;
227 }
228 if (*keylen != dctx->kdf_outlen)
229 return 0;
230 if (!pkey_ec_derive(ctx, NULL, &ktmplen))
231 return 0;
232 if ((ktmp = OPENSSL_malloc(ktmplen)) == NULL) {
233 ERR_raise(ERR_LIB_EC, ERR_R_MALLOC_FAILURE);
234 return 0;
235 }
236 if (!pkey_ec_derive(ctx, ktmp, &ktmplen))
237 goto err;
238 /* Do KDF stuff */
239 if (!ossl_ecdh_kdf_X9_63(key, *keylen, ktmp, ktmplen,
240 dctx->kdf_ukm, dctx->kdf_ukmlen, dctx->kdf_md,
241 ctx->libctx, ctx->propquery))
242 goto err;
243 rv = 1;
244
245 err:
246 OPENSSL_clear_free(ktmp, ktmplen);
247 return rv;
248 }
249 #endif
250
pkey_ec_ctrl(EVP_PKEY_CTX * ctx,int type,int p1,void * p2)251 static int pkey_ec_ctrl(EVP_PKEY_CTX *ctx, int type, int p1, void *p2)
252 {
253 EC_PKEY_CTX *dctx = ctx->data;
254 EC_GROUP *group;
255 switch (type) {
256 case EVP_PKEY_CTRL_EC_PARAMGEN_CURVE_NID:
257 group = EC_GROUP_new_by_curve_name(p1);
258 if (group == NULL) {
259 ERR_raise(ERR_LIB_EC, EC_R_INVALID_CURVE);
260 return 0;
261 }
262 EC_GROUP_free(dctx->gen_group);
263 dctx->gen_group = group;
264 return 1;
265
266 case EVP_PKEY_CTRL_EC_PARAM_ENC:
267 if (!dctx->gen_group) {
268 ERR_raise(ERR_LIB_EC, EC_R_NO_PARAMETERS_SET);
269 return 0;
270 }
271 EC_GROUP_set_asn1_flag(dctx->gen_group, p1);
272 return 1;
273
274 #ifndef OPENSSL_NO_EC
275 case EVP_PKEY_CTRL_EC_ECDH_COFACTOR:
276 if (p1 == -2) {
277 if (dctx->cofactor_mode != -1)
278 return dctx->cofactor_mode;
279 else {
280 const EC_KEY *ec_key = EVP_PKEY_get0_EC_KEY(ctx->pkey);
281 return EC_KEY_get_flags(ec_key) & EC_FLAG_COFACTOR_ECDH ? 1 : 0;
282 }
283 } else if (p1 < -1 || p1 > 1)
284 return -2;
285 dctx->cofactor_mode = p1;
286 if (p1 != -1) {
287 EC_KEY *ec_key = (EC_KEY *)EVP_PKEY_get0_EC_KEY(ctx->pkey);
288
289 /*
290 * We discarded the "const" above. This will only work if the key is
291 * a "real" legacy key, and not a cached copy of a provided key
292 */
293 if (evp_pkey_is_provided(ctx->pkey)) {
294 ERR_raise(ERR_LIB_EC, ERR_R_UNSUPPORTED);
295 return 0;
296 }
297 if (!ec_key->group)
298 return -2;
299 /* If cofactor is 1 cofactor mode does nothing */
300 if (BN_is_one(ec_key->group->cofactor))
301 return 1;
302 if (!dctx->co_key) {
303 dctx->co_key = EC_KEY_dup(ec_key);
304 if (!dctx->co_key)
305 return 0;
306 }
307 if (p1)
308 EC_KEY_set_flags(dctx->co_key, EC_FLAG_COFACTOR_ECDH);
309 else
310 EC_KEY_clear_flags(dctx->co_key, EC_FLAG_COFACTOR_ECDH);
311 } else {
312 EC_KEY_free(dctx->co_key);
313 dctx->co_key = NULL;
314 }
315 return 1;
316 #endif
317
318 case EVP_PKEY_CTRL_EC_KDF_TYPE:
319 if (p1 == -2)
320 return dctx->kdf_type;
321 if (p1 != EVP_PKEY_ECDH_KDF_NONE && p1 != EVP_PKEY_ECDH_KDF_X9_63)
322 return -2;
323 dctx->kdf_type = p1;
324 return 1;
325
326 case EVP_PKEY_CTRL_EC_KDF_MD:
327 dctx->kdf_md = p2;
328 return 1;
329
330 case EVP_PKEY_CTRL_GET_EC_KDF_MD:
331 *(const EVP_MD **)p2 = dctx->kdf_md;
332 return 1;
333
334 case EVP_PKEY_CTRL_EC_KDF_OUTLEN:
335 if (p1 <= 0)
336 return -2;
337 dctx->kdf_outlen = (size_t)p1;
338 return 1;
339
340 case EVP_PKEY_CTRL_GET_EC_KDF_OUTLEN:
341 *(int *)p2 = dctx->kdf_outlen;
342 return 1;
343
344 case EVP_PKEY_CTRL_EC_KDF_UKM:
345 OPENSSL_free(dctx->kdf_ukm);
346 dctx->kdf_ukm = p2;
347 if (p2)
348 dctx->kdf_ukmlen = p1;
349 else
350 dctx->kdf_ukmlen = 0;
351 return 1;
352
353 case EVP_PKEY_CTRL_GET_EC_KDF_UKM:
354 *(unsigned char **)p2 = dctx->kdf_ukm;
355 return dctx->kdf_ukmlen;
356
357 case EVP_PKEY_CTRL_MD:
358 if (EVP_MD_get_type((const EVP_MD *)p2) != NID_sha1 &&
359 EVP_MD_get_type((const EVP_MD *)p2) != NID_ecdsa_with_SHA1 &&
360 EVP_MD_get_type((const EVP_MD *)p2) != NID_sha224 &&
361 EVP_MD_get_type((const EVP_MD *)p2) != NID_sha256 &&
362 EVP_MD_get_type((const EVP_MD *)p2) != NID_sha384 &&
363 EVP_MD_get_type((const EVP_MD *)p2) != NID_sha512 &&
364 EVP_MD_get_type((const EVP_MD *)p2) != NID_sha3_224 &&
365 EVP_MD_get_type((const EVP_MD *)p2) != NID_sha3_256 &&
366 EVP_MD_get_type((const EVP_MD *)p2) != NID_sha3_384 &&
367 EVP_MD_get_type((const EVP_MD *)p2) != NID_sha3_512 &&
368 EVP_MD_get_type((const EVP_MD *)p2) != NID_sm3) {
369 ERR_raise(ERR_LIB_EC, EC_R_INVALID_DIGEST_TYPE);
370 return 0;
371 }
372 dctx->md = p2;
373 return 1;
374
375 case EVP_PKEY_CTRL_GET_MD:
376 *(const EVP_MD **)p2 = dctx->md;
377 return 1;
378
379 case EVP_PKEY_CTRL_PEER_KEY:
380 /* Default behaviour is OK */
381 case EVP_PKEY_CTRL_DIGESTINIT:
382 case EVP_PKEY_CTRL_PKCS7_SIGN:
383 case EVP_PKEY_CTRL_CMS_SIGN:
384 return 1;
385
386 default:
387 return -2;
388
389 }
390 }
391
pkey_ec_ctrl_str(EVP_PKEY_CTX * ctx,const char * type,const char * value)392 static int pkey_ec_ctrl_str(EVP_PKEY_CTX *ctx,
393 const char *type, const char *value)
394 {
395 if (strcmp(type, "ec_paramgen_curve") == 0) {
396 int nid;
397 nid = EC_curve_nist2nid(value);
398 if (nid == NID_undef)
399 nid = OBJ_sn2nid(value);
400 if (nid == NID_undef)
401 nid = OBJ_ln2nid(value);
402 if (nid == NID_undef) {
403 ERR_raise(ERR_LIB_EC, EC_R_INVALID_CURVE);
404 return 0;
405 }
406 return EVP_PKEY_CTX_set_ec_paramgen_curve_nid(ctx, nid);
407 } else if (strcmp(type, "ec_param_enc") == 0) {
408 int param_enc;
409 if (strcmp(value, "explicit") == 0)
410 param_enc = 0;
411 else if (strcmp(value, "named_curve") == 0)
412 param_enc = OPENSSL_EC_NAMED_CURVE;
413 else
414 return -2;
415 return EVP_PKEY_CTX_set_ec_param_enc(ctx, param_enc);
416 } else if (strcmp(type, "ecdh_kdf_md") == 0) {
417 const EVP_MD *md;
418 if ((md = EVP_get_digestbyname(value)) == NULL) {
419 ERR_raise(ERR_LIB_EC, EC_R_INVALID_DIGEST);
420 return 0;
421 }
422 return EVP_PKEY_CTX_set_ecdh_kdf_md(ctx, md);
423 } else if (strcmp(type, "ecdh_cofactor_mode") == 0) {
424 int co_mode;
425 co_mode = atoi(value);
426 return EVP_PKEY_CTX_set_ecdh_cofactor_mode(ctx, co_mode);
427 }
428
429 return -2;
430 }
431
pkey_ec_paramgen(EVP_PKEY_CTX * ctx,EVP_PKEY * pkey)432 static int pkey_ec_paramgen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey)
433 {
434 EC_KEY *ec = NULL;
435 EC_PKEY_CTX *dctx = ctx->data;
436 int ret;
437
438 if (dctx->gen_group == NULL) {
439 ERR_raise(ERR_LIB_EC, EC_R_NO_PARAMETERS_SET);
440 return 0;
441 }
442 ec = EC_KEY_new();
443 if (ec == NULL)
444 return 0;
445 if (!(ret = EC_KEY_set_group(ec, dctx->gen_group))
446 || !ossl_assert(ret = EVP_PKEY_assign_EC_KEY(pkey, ec)))
447 EC_KEY_free(ec);
448 return ret;
449 }
450
pkey_ec_keygen(EVP_PKEY_CTX * ctx,EVP_PKEY * pkey)451 static int pkey_ec_keygen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey)
452 {
453 EC_KEY *ec = NULL;
454 EC_PKEY_CTX *dctx = ctx->data;
455 int ret;
456
457 if (ctx->pkey == NULL && dctx->gen_group == NULL) {
458 ERR_raise(ERR_LIB_EC, EC_R_NO_PARAMETERS_SET);
459 return 0;
460 }
461 ec = EC_KEY_new();
462 if (ec == NULL)
463 return 0;
464 if (!ossl_assert(EVP_PKEY_assign_EC_KEY(pkey, ec))) {
465 EC_KEY_free(ec);
466 return 0;
467 }
468 /* Note: if error is returned, we count on caller to free pkey->pkey.ec */
469 if (ctx->pkey != NULL)
470 ret = EVP_PKEY_copy_parameters(pkey, ctx->pkey);
471 else
472 ret = EC_KEY_set_group(ec, dctx->gen_group);
473
474 return ret ? EC_KEY_generate_key(ec) : 0;
475 }
476
477 static const EVP_PKEY_METHOD ec_pkey_meth = {
478 EVP_PKEY_EC,
479 0,
480 pkey_ec_init,
481 pkey_ec_copy,
482 pkey_ec_cleanup,
483
484 0,
485 pkey_ec_paramgen,
486
487 0,
488 pkey_ec_keygen,
489
490 0,
491 pkey_ec_sign,
492
493 0,
494 pkey_ec_verify,
495
496 0, 0,
497
498 0, 0, 0, 0,
499
500 0,
501 0,
502
503 0,
504 0,
505
506 0,
507 #ifndef OPENSSL_NO_EC
508 pkey_ec_kdf_derive,
509 #else
510 0,
511 #endif
512 pkey_ec_ctrl,
513 pkey_ec_ctrl_str
514 };
515
ossl_ec_pkey_method(void)516 const EVP_PKEY_METHOD *ossl_ec_pkey_method(void)
517 {
518 return &ec_pkey_meth;
519 }
520