1 /*
2 * Copyright 2019-2023 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 * EC_METHOD low level APIs are deprecated for public use, but still ok for
12 * internal use.
13 */
14 #include "internal/deprecated.h"
15
16 #include <stdlib.h>
17 #include <string.h>
18 #include <openssl/err.h>
19 #include <openssl/rand.h>
20 #include "ec_local.h"
21 #include "s390x_arch.h"
22
23 /* Size of parameter blocks */
24 #define S390X_SIZE_PARAM 4096
25
26 /* Size of fields in parameter blocks */
27 #define S390X_SIZE_P256 32
28 #define S390X_SIZE_P384 48
29 #define S390X_SIZE_P521 80
30
31 /* Offsets of fields in PCC parameter blocks */
32 #define S390X_OFF_RES_X(n) (0 * n)
33 #define S390X_OFF_RES_Y(n) (1 * n)
34 #define S390X_OFF_SRC_X(n) (2 * n)
35 #define S390X_OFF_SRC_Y(n) (3 * n)
36 #define S390X_OFF_SCALAR(n) (4 * n)
37
38 /* Offsets of fields in KDSA parameter blocks */
39 #define S390X_OFF_R(n) (0 * n)
40 #define S390X_OFF_S(n) (1 * n)
41 #define S390X_OFF_H(n) (2 * n)
42 #define S390X_OFF_K(n) (3 * n)
43 #define S390X_OFF_X(n) (3 * n)
44 #define S390X_OFF_RN(n) (4 * n)
45 #define S390X_OFF_Y(n) (4 * n)
46
ec_GFp_s390x_nistp_mul(const EC_GROUP * group,EC_POINT * r,const BIGNUM * scalar,size_t num,const EC_POINT * points[],const BIGNUM * scalars[],BN_CTX * ctx,unsigned int fc,int len)47 static int ec_GFp_s390x_nistp_mul(const EC_GROUP *group, EC_POINT *r,
48 const BIGNUM *scalar,
49 size_t num, const EC_POINT *points[],
50 const BIGNUM *scalars[],
51 BN_CTX *ctx, unsigned int fc, int len)
52 {
53 unsigned char param[S390X_SIZE_PARAM];
54 BIGNUM *x, *y;
55 const EC_POINT *point_ptr = NULL;
56 const BIGNUM *scalar_ptr = NULL;
57 BN_CTX *new_ctx = NULL;
58 int rc = -1;
59
60 if (ctx == NULL) {
61 ctx = new_ctx = BN_CTX_new_ex(group->libctx);
62 if (ctx == NULL)
63 return 0;
64 }
65
66 BN_CTX_start(ctx);
67
68 x = BN_CTX_get(ctx);
69 y = BN_CTX_get(ctx);
70 if (x == NULL || y == NULL) {
71 rc = 0;
72 goto ret;
73 }
74
75 /*
76 * Use PCC for EC keygen and ECDH key derivation:
77 * scalar * generator and scalar * peer public key,
78 * scalar in [0,order).
79 */
80 if ((scalar != NULL && num == 0 && BN_is_negative(scalar) == 0)
81 || (scalar == NULL && num == 1 && BN_is_negative(scalars[0]) == 0)) {
82
83 if (num == 0) {
84 point_ptr = EC_GROUP_get0_generator(group);
85 scalar_ptr = scalar;
86 } else {
87 point_ptr = points[0];
88 scalar_ptr = scalars[0];
89 }
90
91 if (EC_POINT_is_at_infinity(group, point_ptr) == 1
92 || BN_is_zero(scalar_ptr)) {
93 rc = EC_POINT_set_to_infinity(group, r);
94 goto ret;
95 }
96
97 memset(¶m, 0, sizeof(param));
98
99 if (group->meth->point_get_affine_coordinates(group, point_ptr,
100 x, y, ctx) != 1
101 || BN_bn2binpad(x, param + S390X_OFF_SRC_X(len), len) == -1
102 || BN_bn2binpad(y, param + S390X_OFF_SRC_Y(len), len) == -1
103 || BN_bn2binpad(scalar_ptr,
104 param + S390X_OFF_SCALAR(len), len) == -1
105 || s390x_pcc(fc, param) != 0
106 || BN_bin2bn(param + S390X_OFF_RES_X(len), len, x) == NULL
107 || BN_bin2bn(param + S390X_OFF_RES_Y(len), len, y) == NULL
108 || group->meth->point_set_affine_coordinates(group, r,
109 x, y, ctx) != 1)
110 goto ret;
111
112 rc = 1;
113 }
114
115 ret:
116 /* Otherwise use default. */
117 if (rc == -1)
118 rc = ossl_ec_wNAF_mul(group, r, scalar, num, points, scalars, ctx);
119 OPENSSL_cleanse(param, sizeof(param));
120 BN_CTX_end(ctx);
121 BN_CTX_free(new_ctx);
122 return rc;
123 }
124
ecdsa_s390x_nistp_sign_sig(const unsigned char * dgst,int dgstlen,const BIGNUM * kinv,const BIGNUM * r,EC_KEY * eckey,unsigned int fc,int len)125 static ECDSA_SIG *ecdsa_s390x_nistp_sign_sig(const unsigned char *dgst,
126 int dgstlen,
127 const BIGNUM *kinv,
128 const BIGNUM *r,
129 EC_KEY *eckey,
130 unsigned int fc, int len)
131 {
132 unsigned char param[S390X_SIZE_PARAM];
133 int ok = 0;
134 BIGNUM *k;
135 ECDSA_SIG *sig;
136 const EC_GROUP *group;
137 const BIGNUM *privkey;
138 int off;
139
140 group = EC_KEY_get0_group(eckey);
141 privkey = EC_KEY_get0_private_key(eckey);
142 if (group == NULL || privkey == NULL) {
143 ERR_raise(ERR_LIB_EC, EC_R_MISSING_PARAMETERS);
144 return NULL;
145 }
146
147 if (!EC_KEY_can_sign(eckey)) {
148 ERR_raise(ERR_LIB_EC, EC_R_CURVE_DOES_NOT_SUPPORT_SIGNING);
149 return NULL;
150 }
151
152 k = BN_secure_new();
153 sig = ECDSA_SIG_new();
154 if (k == NULL || sig == NULL) {
155 ERR_raise(ERR_LIB_EC, ERR_R_ECDSA_LIB);
156 goto ret;
157 }
158
159 sig->r = BN_new();
160 sig->s = BN_new();
161 if (sig->r == NULL || sig->s == NULL) {
162 ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
163 goto ret;
164 }
165
166 memset(param, 0, sizeof(param));
167 off = len - (dgstlen > len ? len : dgstlen);
168 memcpy(param + S390X_OFF_H(len) + off, dgst, len - off);
169
170 if (BN_bn2binpad(privkey, param + S390X_OFF_K(len), len) == -1) {
171 ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
172 goto ret;
173 }
174
175 if (r == NULL || kinv == NULL) {
176 if (len < 0) {
177 ERR_raise(ERR_LIB_EC, EC_R_INVALID_LENGTH);
178 goto ret;
179 }
180 /*
181 * Generate random k and copy to param block. RAND_priv_bytes_ex
182 * is used instead of BN_priv_rand_range or BN_generate_dsa_nonce
183 * because kdsa instruction constructs an in-range, invertible nonce
184 * internally implementing counter-measures for RNG weakness.
185 */
186 if (RAND_priv_bytes_ex(eckey->libctx, param + S390X_OFF_RN(len),
187 (size_t)len, 0) != 1) {
188 ERR_raise(ERR_LIB_EC, EC_R_RANDOM_NUMBER_GENERATION_FAILED);
189 goto ret;
190 }
191 } else {
192 /* Reconstruct k = (k^-1)^-1. */
193 if (ossl_ec_group_do_inverse_ord(group, k, kinv, NULL) == 0
194 || BN_bn2binpad(k, param + S390X_OFF_RN(len), len) == -1) {
195 ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
196 goto ret;
197 }
198 /* Turns KDSA internal nonce-generation off. */
199 fc |= S390X_KDSA_D;
200 }
201
202 if (s390x_kdsa(fc, param, NULL, 0) != 0) {
203 ERR_raise(ERR_LIB_EC, ERR_R_ECDSA_LIB);
204 goto ret;
205 }
206
207 if (BN_bin2bn(param + S390X_OFF_R(len), len, sig->r) == NULL
208 || BN_bin2bn(param + S390X_OFF_S(len), len, sig->s) == NULL) {
209 ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
210 goto ret;
211 }
212
213 ok = 1;
214 ret:
215 OPENSSL_cleanse(param, sizeof(param));
216 if (ok != 1) {
217 ECDSA_SIG_free(sig);
218 sig = NULL;
219 }
220 BN_clear_free(k);
221 return sig;
222 }
223
ecdsa_s390x_nistp_verify_sig(const unsigned char * dgst,int dgstlen,const ECDSA_SIG * sig,EC_KEY * eckey,unsigned int fc,int len)224 static int ecdsa_s390x_nistp_verify_sig(const unsigned char *dgst, int dgstlen,
225 const ECDSA_SIG *sig, EC_KEY *eckey,
226 unsigned int fc, int len)
227 {
228 unsigned char param[S390X_SIZE_PARAM];
229 int rc = -1;
230 BN_CTX *ctx;
231 BIGNUM *x, *y;
232 const EC_GROUP *group;
233 const EC_POINT *pubkey;
234 int off;
235
236 group = EC_KEY_get0_group(eckey);
237 pubkey = EC_KEY_get0_public_key(eckey);
238 if (eckey == NULL || group == NULL || pubkey == NULL || sig == NULL) {
239 ERR_raise(ERR_LIB_EC, EC_R_MISSING_PARAMETERS);
240 return -1;
241 }
242
243 if (!EC_KEY_can_sign(eckey)) {
244 ERR_raise(ERR_LIB_EC, EC_R_CURVE_DOES_NOT_SUPPORT_SIGNING);
245 return -1;
246 }
247
248 ctx = BN_CTX_new_ex(group->libctx);
249 if (ctx == NULL) {
250 ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
251 return -1;
252 }
253
254 BN_CTX_start(ctx);
255
256 x = BN_CTX_get(ctx);
257 y = BN_CTX_get(ctx);
258 if (x == NULL || y == NULL) {
259 ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
260 goto ret;
261 }
262
263 memset(param, 0, sizeof(param));
264 off = len - (dgstlen > len ? len : dgstlen);
265 memcpy(param + S390X_OFF_H(len) + off, dgst, len - off);
266
267 if (group->meth->point_get_affine_coordinates(group, pubkey,
268 x, y, ctx) != 1
269 || BN_bn2binpad(sig->r, param + S390X_OFF_R(len), len) == -1
270 || BN_bn2binpad(sig->s, param + S390X_OFF_S(len), len) == -1
271 || BN_bn2binpad(x, param + S390X_OFF_X(len), len) == -1
272 || BN_bn2binpad(y, param + S390X_OFF_Y(len), len) == -1) {
273 ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
274 goto ret;
275 }
276
277 rc = s390x_kdsa(fc, param, NULL, 0) == 0 ? 1 : 0;
278 ret:
279 BN_CTX_end(ctx);
280 BN_CTX_free(ctx);
281 return rc;
282 }
283
284 #define EC_GFP_S390X_NISTP_METHOD(bits) \
285 \
286 static int ec_GFp_s390x_nistp##bits##_mul(const EC_GROUP *group, \
287 EC_POINT *r, \
288 const BIGNUM *scalar, \
289 size_t num, \
290 const EC_POINT *points[], \
291 const BIGNUM *scalars[], \
292 BN_CTX *ctx) \
293 { \
294 return ec_GFp_s390x_nistp_mul(group, r, scalar, num, points, \
295 scalars, ctx, \
296 S390X_SCALAR_MULTIPLY_P##bits, \
297 S390X_SIZE_P##bits); \
298 } \
299 \
300 static ECDSA_SIG *ecdsa_s390x_nistp##bits##_sign_sig(const unsigned \
301 char *dgst, \
302 int dgstlen, \
303 const BIGNUM *kinv,\
304 const BIGNUM *r, \
305 EC_KEY *eckey) \
306 { \
307 return ecdsa_s390x_nistp_sign_sig(dgst, dgstlen, kinv, r, eckey, \
308 S390X_ECDSA_SIGN_P##bits, \
309 S390X_SIZE_P##bits); \
310 } \
311 \
312 static int ecdsa_s390x_nistp##bits##_verify_sig(const \
313 unsigned char *dgst, \
314 int dgstlen, \
315 const ECDSA_SIG *sig, \
316 EC_KEY *eckey) \
317 { \
318 return ecdsa_s390x_nistp_verify_sig(dgst, dgstlen, sig, eckey, \
319 S390X_ECDSA_VERIFY_P##bits, \
320 S390X_SIZE_P##bits); \
321 } \
322 \
323 const EC_METHOD *EC_GFp_s390x_nistp##bits##_method(void) \
324 { \
325 static const EC_METHOD EC_GFp_s390x_nistp##bits##_meth = { \
326 EC_FLAGS_DEFAULT_OCT, \
327 NID_X9_62_prime_field, \
328 ossl_ec_GFp_simple_group_init, \
329 ossl_ec_GFp_simple_group_finish, \
330 ossl_ec_GFp_simple_group_clear_finish, \
331 ossl_ec_GFp_simple_group_copy, \
332 ossl_ec_GFp_simple_group_set_curve, \
333 ossl_ec_GFp_simple_group_get_curve, \
334 ossl_ec_GFp_simple_group_get_degree, \
335 ossl_ec_group_simple_order_bits, \
336 ossl_ec_GFp_simple_group_check_discriminant, \
337 ossl_ec_GFp_simple_point_init, \
338 ossl_ec_GFp_simple_point_finish, \
339 ossl_ec_GFp_simple_point_clear_finish, \
340 ossl_ec_GFp_simple_point_copy, \
341 ossl_ec_GFp_simple_point_set_to_infinity, \
342 ossl_ec_GFp_simple_point_set_affine_coordinates, \
343 ossl_ec_GFp_simple_point_get_affine_coordinates, \
344 NULL, /* point_set_compressed_coordinates */ \
345 NULL, /* point2oct */ \
346 NULL, /* oct2point */ \
347 ossl_ec_GFp_simple_add, \
348 ossl_ec_GFp_simple_dbl, \
349 ossl_ec_GFp_simple_invert, \
350 ossl_ec_GFp_simple_is_at_infinity, \
351 ossl_ec_GFp_simple_is_on_curve, \
352 ossl_ec_GFp_simple_cmp, \
353 ossl_ec_GFp_simple_make_affine, \
354 ossl_ec_GFp_simple_points_make_affine, \
355 ec_GFp_s390x_nistp##bits##_mul, \
356 NULL, /* precompute_mult */ \
357 NULL, /* have_precompute_mult */ \
358 ossl_ec_GFp_simple_field_mul, \
359 ossl_ec_GFp_simple_field_sqr, \
360 NULL, /* field_div */ \
361 ossl_ec_GFp_simple_field_inv, \
362 NULL, /* field_encode */ \
363 NULL, /* field_decode */ \
364 NULL, /* field_set_to_one */ \
365 ossl_ec_key_simple_priv2oct, \
366 ossl_ec_key_simple_oct2priv, \
367 NULL, /* set_private */ \
368 ossl_ec_key_simple_generate_key, \
369 ossl_ec_key_simple_check_key, \
370 ossl_ec_key_simple_generate_public_key, \
371 NULL, /* keycopy */ \
372 NULL, /* keyfinish */ \
373 ossl_ecdh_simple_compute_key, \
374 ossl_ecdsa_simple_sign_setup, \
375 ecdsa_s390x_nistp##bits##_sign_sig, \
376 ecdsa_s390x_nistp##bits##_verify_sig, \
377 NULL, /* field_inverse_mod_ord */ \
378 ossl_ec_GFp_simple_blind_coordinates, \
379 ossl_ec_GFp_simple_ladder_pre, \
380 ossl_ec_GFp_simple_ladder_step, \
381 ossl_ec_GFp_simple_ladder_post \
382 }; \
383 static const EC_METHOD *ret; \
384 \
385 if ((OPENSSL_s390xcap_P.pcc[1] \
386 & S390X_CAPBIT(S390X_SCALAR_MULTIPLY_P##bits)) \
387 && (OPENSSL_s390xcap_P.kdsa[0] \
388 & S390X_CAPBIT(S390X_ECDSA_VERIFY_P##bits)) \
389 && (OPENSSL_s390xcap_P.kdsa[0] \
390 & S390X_CAPBIT(S390X_ECDSA_SIGN_P##bits))) \
391 ret = &EC_GFp_s390x_nistp##bits##_meth; \
392 else \
393 ret = EC_GFp_mont_method(); \
394 \
395 return ret; \
396 }
397
398 EC_GFP_S390X_NISTP_METHOD(256)
399 EC_GFP_S390X_NISTP_METHOD(384)
400 EC_GFP_S390X_NISTP_METHOD(521)
401
