crypto/ec/ecp_s390x_nistp.c

   1 /*
   2  * Copyright 2019-2020 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
  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(&param, 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 = ec_wNAF_mul(group, r, scalar, num, points, scalars, ctx);
 119     OPENSSL_cleanse(param + S390X_OFF_SCALAR(len), len);
 120     BN_CTX_end(ctx);
 121     BN_CTX_free(new_ctx);
 122     return rc;
 123 }
 124
 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         ECerr(EC_F_ECDSA_S390X_NISTP_SIGN_SIG, EC_R_MISSING_PARAMETERS);
 144         return NULL;
 145     }
 146
 147     if (!EC_KEY_can_sign(eckey)) {
 148         ECerr(EC_F_ECDSA_S390X_NISTP_SIGN_SIG,
 149               EC_R_CURVE_DOES_NOT_SUPPORT_SIGNING);
 150         return NULL;
 151     }
 152
 153     k = BN_secure_new();
 154     sig = ECDSA_SIG_new();
 155     if (k == NULL || sig == NULL) {
 156         ECerr(EC_F_ECDSA_S390X_NISTP_SIGN_SIG, ERR_R_MALLOC_FAILURE);
 157         goto ret;
 158     }
 159
 160     sig->r = BN_new();
 161     sig->s = BN_new();
 162     if (sig->r == NULL || sig->s == NULL) {
 163         ECerr(EC_F_ECDSA_S390X_NISTP_SIGN_SIG, ERR_R_MALLOC_FAILURE);
 164         goto ret;
 165     }
 166
 167     memset(param, 0, sizeof(param));
 168     off = len - (dgstlen > len ? len : dgstlen);
 169     memcpy(param + S390X_OFF_H(len) + off, dgst, len - off);
 170
 171     if (BN_bn2binpad(privkey, param + S390X_OFF_K(len), len) == -1) {
 172         ECerr(EC_F_ECDSA_S390X_NISTP_SIGN_SIG, ERR_R_BN_LIB);
 173         goto ret;
 174     }
 175
 176     if (r == NULL || kinv == NULL) {
 177         /*
 178          * Generate random k and copy to param param block. RAND_priv_bytes_ex
 179          * is used instead of BN_priv_rand_range or BN_generate_dsa_nonce
 180          * because kdsa instruction constructs an in-range, invertible nonce
 181          * internally implementing counter-measures for RNG weakness.
 182          */
 183          if (RAND_priv_bytes_ex(eckey->libctx, param + S390X_OFF_RN(len),
 184                                 len) != 1) {
 185              ECerr(EC_F_ECDSA_S390X_NISTP_SIGN_SIG,
 186                    EC_R_RANDOM_NUMBER_GENERATION_FAILED);
 187              goto ret;
 188          }
 189     } else {
 190         /* Reconstruct k = (k^-1)^-1. */
 191         if (ec_group_do_inverse_ord(group, k, kinv, NULL) == 0
 192             || BN_bn2binpad(k, param + S390X_OFF_RN(len), len) == -1) {
 193             ECerr(EC_F_ECDSA_S390X_NISTP_SIGN_SIG, ERR_R_BN_LIB);
 194             goto ret;
 195         }
 196         /* Turns KDSA internal nonce-generation off. */
 197         fc |= S390X_KDSA_D;
 198     }
 199
 200     if (s390x_kdsa(fc, param, NULL, 0) != 0) {
 201         ECerr(EC_F_ECDSA_S390X_NISTP_SIGN_SIG, ERR_R_ECDSA_LIB);
 202         goto ret;
 203     }
 204
 205     if (BN_bin2bn(param + S390X_OFF_R(len), len, sig->r) == NULL
 206         || BN_bin2bn(param + S390X_OFF_S(len), len, sig->s) == NULL) {
 207         ECerr(EC_F_ECDSA_S390X_NISTP_SIGN_SIG, ERR_R_BN_LIB);
 208         goto ret;
 209     }
 210
 211     ok = 1;
 212 ret:
 213     OPENSSL_cleanse(param + S390X_OFF_K(len), 2 * len);
 214     if (ok != 1) {
 215         ECDSA_SIG_free(sig);
 216         sig = NULL;
 217     }
 218     BN_clear_free(k);
 219     return sig;
 220 }
 221
 222 static int ecdsa_s390x_nistp_verify_sig(const unsigned char *dgst, int dgstlen,
 223                                         const ECDSA_SIG *sig, EC_KEY *eckey,
 224                                         unsigned int fc, int len)
 225 {
 226     unsigned char param[S390X_SIZE_PARAM];
 227     int rc = -1;
 228     BN_CTX *ctx;
 229     BIGNUM *x, *y;
 230     const EC_GROUP *group;
 231     const EC_POINT *pubkey;
 232     int off;
 233
 234     group = EC_KEY_get0_group(eckey);
 235     pubkey = EC_KEY_get0_public_key(eckey);
 236     if (eckey == NULL || group == NULL || pubkey == NULL || sig == NULL) {
 237         ECerr(EC_F_ECDSA_S390X_NISTP_VERIFY_SIG, EC_R_MISSING_PARAMETERS);
 238         return -1;
 239     }
 240
 241     if (!EC_KEY_can_sign(eckey)) {
 242         ECerr(EC_F_ECDSA_S390X_NISTP_VERIFY_SIG,
 243               EC_R_CURVE_DOES_NOT_SUPPORT_SIGNING);
 244         return -1;
 245     }
 246
 247     ctx = BN_CTX_new_ex(group->libctx);
 248     if (ctx == NULL) {
 249         ECerr(EC_F_ECDSA_S390X_NISTP_VERIFY_SIG, ERR_R_MALLOC_FAILURE);
 250         return -1;
 251     }
 252
 253     BN_CTX_start(ctx);
 254
 255     x = BN_CTX_get(ctx);
 256     y = BN_CTX_get(ctx);
 257     if (x == NULL || y == NULL) {
 258         ECerr(EC_F_ECDSA_S390X_NISTP_VERIFY_SIG, ERR_R_MALLOC_FAILURE);
 259         goto ret;
 260     }
 261
 262     memset(param, 0, sizeof(param));
 263     off = len - (dgstlen > len ? len : dgstlen);
 264     memcpy(param + S390X_OFF_H(len) + off, dgst, len - off);
 265
 266     if (group->meth->point_get_affine_coordinates(group, pubkey,
 267                                                   x, y, ctx) != 1
 268         || BN_bn2binpad(sig->r, param + S390X_OFF_R(len), len) == -1
 269         || BN_bn2binpad(sig->s, param + S390X_OFF_S(len), len) == -1
 270         || BN_bn2binpad(x, param + S390X_OFF_X(len), len) == -1
 271         || BN_bn2binpad(y, param + S390X_OFF_Y(len), len) == -1) {
 272         ECerr(EC_F_ECDSA_S390X_NISTP_VERIFY_SIG, ERR_R_BN_LIB);
 273         goto ret;
 274     }
 275
 276     rc = s390x_kdsa(fc, param, NULL, 0) == 0 ? 1 : 0;
 277 ret:
 278     BN_CTX_end(ctx);
 279     BN_CTX_free(ctx);
 280     return rc;
 281 }
 282
 283 #define EC_GFP_S390X_NISTP_METHOD(bits)                                 \
 284                                                                         \
 285 static int ec_GFp_s390x_nistp##bits##_mul(const EC_GROUP *group,        \
 286                                           EC_POINT *r,                  \
 287                                           const BIGNUM *scalar,         \
 288                                           size_t num,                   \
 289                                           const EC_POINT *points[],     \
 290                                           const BIGNUM *scalars[],      \
 291                                           BN_CTX *ctx)                  \
 292 {                                                                       \
 293     return ec_GFp_s390x_nistp_mul(group, r, scalar, num, points,        \
 294                                   scalars, ctx,                         \
 295                                   S390X_SCALAR_MULTIPLY_P##bits,        \
 296                                   S390X_SIZE_P##bits);                  \
 297 }                                                                       \
 298                                                                         \
 299 static ECDSA_SIG *ecdsa_s390x_nistp##bits##_sign_sig(const unsigned     \
 300                                                      char *dgst,        \
 301                                                      int dgstlen,       \
 302                                                      const BIGNUM *kinv,\
 303                                                      const BIGNUM *r,   \
 304                                                      EC_KEY *eckey)     \
 305 {                                                                       \
 306     return ecdsa_s390x_nistp_sign_sig(dgst, dgstlen, kinv, r, eckey,    \
 307                                       S390X_ECDSA_SIGN_P##bits,         \
 308                                       S390X_SIZE_P##bits);              \
 309 }                                                                       \
 310                                                                         \
 311 static int ecdsa_s390x_nistp##bits##_verify_sig(const                   \
 312                                                 unsigned char *dgst,    \
 313                                                 int dgstlen,            \
 314                                                 const ECDSA_SIG *sig,   \
 315                                                 EC_KEY *eckey)          \
 316 {                                                                       \
 317     return ecdsa_s390x_nistp_verify_sig(dgst, dgstlen, sig, eckey,      \
 318                                         S390X_ECDSA_VERIFY_P##bits,     \
 319                                         S390X_SIZE_P##bits);            \
 320 }                                                                       \
 321                                                                         \
 322 const EC_METHOD *EC_GFp_s390x_nistp##bits##_method(void)                \
 323 {                                                                       \
 324     static const EC_METHOD EC_GFp_s390x_nistp##bits##_meth = {          \
 325         EC_FLAGS_DEFAULT_OCT,                                           \
 326         NID_X9_62_prime_field,                                          \
 327         ec_GFp_simple_group_init,                                       \
 328         ec_GFp_simple_group_finish,                                     \
 329         ec_GFp_simple_group_clear_finish,                               \
 330         ec_GFp_simple_group_copy,                                       \
 331         ec_GFp_simple_group_set_curve,                                  \
 332         ec_GFp_simple_group_get_curve,                                  \
 333         ec_GFp_simple_group_get_degree,                                 \
 334         ec_group_simple_order_bits,                                     \
 335         ec_GFp_simple_group_check_discriminant,                         \
 336         ec_GFp_simple_point_init,                                       \
 337         ec_GFp_simple_point_finish,                                     \
 338         ec_GFp_simple_point_clear_finish,                               \
 339         ec_GFp_simple_point_copy,                                       \
 340         ec_GFp_simple_point_set_to_infinity,                            \
 341         ec_GFp_simple_point_set_affine_coordinates,                     \
 342         ec_GFp_simple_point_get_affine_coordinates,                     \
 343         NULL, /* point_set_compressed_coordinates */                    \
 344         NULL, /* point2oct */                                           \
 345         NULL, /* oct2point */                                           \
 346         ec_GFp_simple_add,                                              \
 347         ec_GFp_simple_dbl,                                              \
 348         ec_GFp_simple_invert,                                           \
 349         ec_GFp_simple_is_at_infinity,                                   \
 350         ec_GFp_simple_is_on_curve,                                      \
 351         ec_GFp_simple_cmp,                                              \
 352         ec_GFp_simple_make_affine,                                      \
 353         ec_GFp_simple_points_make_affine,                               \
 354         ec_GFp_s390x_nistp##bits##_mul,                                 \
 355         NULL, /* precompute_mult */                                     \
 356         NULL, /* have_precompute_mult */                                \
 357         ec_GFp_simple_field_mul,                                        \
 358         ec_GFp_simple_field_sqr,                                        \
 359         NULL, /* field_div */                                           \
 360         ec_GFp_simple_field_inv,                                        \
 361         NULL, /* field_encode */                                        \
 362         NULL, /* field_decode */                                        \
 363         NULL, /* field_set_to_one */                                    \
 364         ec_key_simple_priv2oct,                                         \
 365         ec_key_simple_oct2priv,                                         \
 366         NULL, /* set_private */                                         \
 367         ec_key_simple_generate_key,                                     \
 368         ec_key_simple_check_key,                                        \
 369         ec_key_simple_generate_public_key,                              \
 370         NULL, /* keycopy */                                             \
 371         NULL, /* keyfinish */                                           \
 372         ecdh_simple_compute_key,                                        \
 373         ecdsa_simple_sign_setup,                                        \
 374         ecdsa_s390x_nistp##bits##_sign_sig,                             \
 375         ecdsa_s390x_nistp##bits##_verify_sig,                           \
 376         NULL, /* field_inverse_mod_ord */                               \
 377         ec_GFp_simple_blind_coordinates,                                \
 378         ec_GFp_simple_ladder_pre,                                       \
 379         ec_GFp_simple_ladder_step,                                      \
 380         ec_GFp_simple_ladder_post                                       \
 381     };                                                                  \
 382     static const EC_METHOD *ret;                                        \
 383                                                                         \
 384     if ((OPENSSL_s390xcap_P.pcc[1]                                      \
 385          & S390X_CAPBIT(S390X_SCALAR_MULTIPLY_P##bits))                 \
 386         && (OPENSSL_s390xcap_P.kdsa[0]                                  \
 387             & S390X_CAPBIT(S390X_ECDSA_VERIFY_P##bits))                 \
 388         && (OPENSSL_s390xcap_P.kdsa[0]                                  \
 389             & S390X_CAPBIT(S390X_ECDSA_SIGN_P##bits)))                  \
 390         ret = &EC_GFp_s390x_nistp##bits##_meth;                         \
 391     else                                                                \
 392         ret = EC_GFp_mont_method();                                     \
 393                                                                         \
 394     return ret;                                                         \
 395 }
 396
 397 EC_GFP_S390X_NISTP_METHOD(256)
 398 EC_GFP_S390X_NISTP_METHOD(384)
 399 EC_GFP_S390X_NISTP_METHOD(521)