release/src/router/openssl/crypto/ecdsa/ecs_ossl.c

   1 /* crypto/ecdsa/ecs_ossl.c */
   2 /*
   3  * Written by Nils Larsch for the OpenSSL project
   4  */
   5 /* ====================================================================
   6  * Copyright (c) 1998-2004 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  *    openssl-core@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 "ecs_locl.h"
  60 #include <openssl/err.h>
  61 #include <openssl/obj_mac.h>
  62 #include <openssl/bn.h>
  63
  64 static ECDSA_SIG *ecdsa_do_sign(const unsigned char *dgst, int dlen,
  65                 const BIGNUM *, const BIGNUM *, EC_KEY *eckey);
  66 static int ecdsa_sign_setup(EC_KEY *eckey, BN_CTX *ctx_in, BIGNUM **kinvp,
  67                 BIGNUM **rp);
  68 static int ecdsa_do_verify(const unsigned char *dgst, int dgst_len,
  69                 const ECDSA_SIG *sig, EC_KEY *eckey);
  70
  71 static ECDSA_METHOD openssl_ecdsa_meth = {
  72         "OpenSSL ECDSA method",
  73         ecdsa_do_sign,
  74         ecdsa_sign_setup,
  75         ecdsa_do_verify,
  76 #if 0
  77         NULL, /* init     */
  78         NULL, /* finish   */
  79 #endif
  80         0,    /* flags    */
  81         NULL  /* app_data */
  82 };
  83
  84 const ECDSA_METHOD *ECDSA_OpenSSL(void)
  85 {
  86         return &openssl_ecdsa_meth;
  87 }
  88
  89 static int ecdsa_sign_setup(EC_KEY *eckey, BN_CTX *ctx_in, BIGNUM **kinvp,
  90                 BIGNUM **rp)
  91 {
  92         BN_CTX   *ctx = NULL;
  93         BIGNUM   *k = NULL, *r = NULL, *order = NULL, *X = NULL;
  94         EC_POINT *tmp_point=NULL;
  95         const EC_GROUP *group;
  96         int      ret = 0;
  97
  98         if (eckey == NULL || (group = EC_KEY_get0_group(eckey)) == NULL)
  99         {
 100                 ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_PASSED_NULL_PARAMETER);
 101                 return 0;
 102         }
 103
 104         if (ctx_in == NULL)
 105         {
 106                 if ((ctx = BN_CTX_new()) == NULL)
 107                 {
 108                         ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP,ERR_R_MALLOC_FAILURE);
 109                         return 0;
 110                 }
 111         }
 112         else
 113                 ctx = ctx_in;
 114
 115         k     = BN_new();       /* this value is later returned in *kinvp */
 116         r     = BN_new();       /* this value is later returned in *rp    */
 117         order = BN_new();
 118         X     = BN_new();
 119         if (!k || !r || !order || !X)
 120         {
 121                 ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_MALLOC_FAILURE);
 122                 goto err;
 123         }
 124         if ((tmp_point = EC_POINT_new(group)) == NULL)
 125         {
 126                 ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_EC_LIB);
 127                 goto err;
 128         }
 129         if (!EC_GROUP_get_order(group, order, ctx))
 130         {
 131                 ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_EC_LIB);
 132                 goto err;
 133         }
 134
 135         do
 136         {
 137                 /* get random k */
 138                 do
 139                         if (!BN_rand_range(k, order))
 140                         {
 141                                 ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP,
 142                                  ECDSA_R_RANDOM_NUMBER_GENERATION_FAILED);
 143                                 goto err;
 144                         }
 145                 while (BN_is_zero(k));
 146
 147                 /* We do not want timing information to leak the length of k,
 148                  * so we compute G*k using an equivalent scalar of fixed
 149                  * bit-length. */
 150
 151                 if (!BN_add(k, k, order)) goto err;
 152                 if (BN_num_bits(k) <= BN_num_bits(order))
 153                         if (!BN_add(k, k, order)) goto err;
 154
 155                 /* compute r the x-coordinate of generator * k */
 156                 if (!EC_POINT_mul(group, tmp_point, k, NULL, NULL, ctx))
 157                 {
 158                         ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_EC_LIB);
 159                         goto err;
 160                 }
 161                 if (EC_METHOD_get_field_type(EC_GROUP_method_of(group)) == NID_X9_62_prime_field)
 162                 {
 163                         if (!EC_POINT_get_affine_coordinates_GFp(group,
 164                                 tmp_point, X, NULL, ctx))
 165                         {
 166                                 ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP,ERR_R_EC_LIB);
 167                                 goto err;
 168                         }
 169                 }
 170 #ifndef OPENSSL_NO_EC2M
 171                 else /* NID_X9_62_characteristic_two_field */
 172                 {
 173                         if (!EC_POINT_get_affine_coordinates_GF2m(group,
 174                                 tmp_point, X, NULL, ctx))
 175                         {
 176                                 ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP,ERR_R_EC_LIB);
 177                                 goto err;
 178                         }
 179                 }
 180 #endif
 181                 if (!BN_nnmod(r, X, order, ctx))
 182                 {
 183                         ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_BN_LIB);
 184                         goto err;
 185                 }
 186         }
 187         while (BN_is_zero(r));
 188
 189         /* compute the inverse of k */
 190         if (!BN_mod_inverse(k, k, order, ctx))
 191         {
 192                 ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_BN_LIB);
 193                 goto err;
 194         }
 195         /* clear old values if necessary */
 196         if (*rp != NULL)
 197                 BN_clear_free(*rp);
 198         if (*kinvp != NULL)
 199                 BN_clear_free(*kinvp);
 200         /* save the pre-computed values  */
 201         *rp    = r;
 202         *kinvp = k;
 203         ret = 1;
 204 err:
 205         if (!ret)
 206         {
 207                 if (k != NULL) BN_clear_free(k);
 208                 if (r != NULL) BN_clear_free(r);
 209         }
 210         if (ctx_in == NULL)
 211                 BN_CTX_free(ctx);
 212         if (order != NULL)
 213                 BN_free(order);
 214         if (tmp_point != NULL)
 215                 EC_POINT_free(tmp_point);
 216         if (X)
 217                 BN_clear_free(X);
 218         return(ret);
 219 }
 220
 221
 222 static ECDSA_SIG *ecdsa_do_sign(const unsigned char *dgst, int dgst_len,
 223                 const BIGNUM *in_kinv, const BIGNUM *in_r, EC_KEY *eckey)
 224 {
 225         int     ok = 0, i;
 226         BIGNUM *kinv=NULL, *s, *m=NULL,*tmp=NULL,*order=NULL;
 227         const BIGNUM *ckinv;
 228         BN_CTX     *ctx = NULL;
 229         const EC_GROUP   *group;
 230         ECDSA_SIG  *ret;
 231         ECDSA_DATA *ecdsa;
 232         const BIGNUM *priv_key;
 233
 234         ecdsa    = ecdsa_check(eckey);
 235         group    = EC_KEY_get0_group(eckey);
 236         priv_key = EC_KEY_get0_private_key(eckey);
 237
 238         if (group == NULL || priv_key == NULL || ecdsa == NULL)
 239         {
 240                 ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_PASSED_NULL_PARAMETER);
 241                 return NULL;
 242         }
 243
 244         ret = ECDSA_SIG_new();
 245         if (!ret)
 246         {
 247                 ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_MALLOC_FAILURE);
 248                 return NULL;
 249         }
 250         s = ret->s;
 251
 252         if ((ctx = BN_CTX_new()) == NULL || (order = BN_new()) == NULL ||
 253                 (tmp = BN_new()) == NULL || (m = BN_new()) == NULL)
 254         {
 255                 ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_MALLOC_FAILURE);
 256                 goto err;
 257         }
 258
 259         if (!EC_GROUP_get_order(group, order, ctx))
 260         {
 261                 ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_EC_LIB);
 262                 goto err;
 263         }
 264         i = BN_num_bits(order);
 265         /* Need to truncate digest if it is too long: first truncate whole
 266          * bytes.
 267          */
 268         if (8 * dgst_len > i)
 269                 dgst_len = (i + 7)/8;
 270         if (!BN_bin2bn(dgst, dgst_len, m))
 271         {
 272                 ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_BN_LIB);
 273                 goto err;
 274         }
 275         /* If still too long truncate remaining bits with a shift */
 276         if ((8 * dgst_len > i) && !BN_rshift(m, m, 8 - (i & 0x7)))
 277         {
 278                 ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_BN_LIB);
 279                 goto err;
 280         }
 281         do
 282         {
 283                 if (in_kinv == NULL || in_r == NULL)
 284                 {
 285                         if (!ECDSA_sign_setup(eckey, ctx, &kinv, &ret->r))
 286                         {
 287                                 ECDSAerr(ECDSA_F_ECDSA_DO_SIGN,ERR_R_ECDSA_LIB);
 288                                 goto err;
 289                         }
 290                         ckinv = kinv;
 291                 }
 292                 else
 293                 {
 294                         ckinv  = in_kinv;
 295                         if (BN_copy(ret->r, in_r) == NULL)
 296                         {
 297                                 ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_MALLOC_FAILURE);
 298                                 goto err;
 299                         }
 300                 }
 301
 302                 if (!BN_mod_mul(tmp, priv_key, ret->r, order, ctx))
 303                 {
 304                         ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_BN_LIB);
 305                         goto err;
 306                 }
 307                 if (!BN_mod_add_quick(s, tmp, m, order))
 308                 {
 309                         ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_BN_LIB);
 310                         goto err;
 311                 }
 312                 if (!BN_mod_mul(s, s, ckinv, order, ctx))
 313                 {
 314                         ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_BN_LIB);
 315                         goto err;
 316                 }
 317                 if (BN_is_zero(s))
 318                 {
 319                         /* if kinv and r have been supplied by the caller
 320                          * don't to generate new kinv and r values */
 321                         if (in_kinv != NULL && in_r != NULL)
 322                         {
 323                                 ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ECDSA_R_NEED_NEW_SETUP_VALUES);
 324                                 goto err;
 325                         }
 326                 }
 327                 else
 328                         /* s != 0 => we have a valid signature */
 329                         break;
 330         }
 331         while (1);
 332
 333         ok = 1;
 334 err:
 335         if (!ok)
 336         {
 337                 ECDSA_SIG_free(ret);
 338                 ret = NULL;
 339         }
 340         if (ctx)
 341                 BN_CTX_free(ctx);
 342         if (m)
 343                 BN_clear_free(m);
 344         if (tmp)
 345                 BN_clear_free(tmp);
 346         if (order)
 347                 BN_free(order);
 348         if (kinv)
 349                 BN_clear_free(kinv);
 350         return ret;
 351 }
 352
 353 static int ecdsa_do_verify(const unsigned char *dgst, int dgst_len,
 354                 const ECDSA_SIG *sig, EC_KEY *eckey)
 355 {
 356         int ret = -1, i;
 357         BN_CTX   *ctx;
 358         BIGNUM   *order, *u1, *u2, *m, *X;
 359         EC_POINT *point = NULL;
 360         const EC_GROUP *group;
 361         const EC_POINT *pub_key;
 362
 363         /* check input values */
 364         if (eckey == NULL || (group = EC_KEY_get0_group(eckey)) == NULL ||
 365             (pub_key = EC_KEY_get0_public_key(eckey)) == NULL || sig == NULL)
 366         {
 367                 ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ECDSA_R_MISSING_PARAMETERS);
 368                 return -1;
 369         }
 370
 371         ctx = BN_CTX_new();
 372         if (!ctx)
 373         {
 374                 ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_MALLOC_FAILURE);
 375                 return -1;
 376         }
 377         BN_CTX_start(ctx);
 378         order = BN_CTX_get(ctx);
 379         u1    = BN_CTX_get(ctx);
 380         u2    = BN_CTX_get(ctx);
 381         m     = BN_CTX_get(ctx);
 382         X     = BN_CTX_get(ctx);
 383         if (!X)
 384         {
 385                 ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_BN_LIB);
 386                 goto err;
 387         }
 388
 389         if (!EC_GROUP_get_order(group, order, ctx))
 390         {
 391                 ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_EC_LIB);
 392                 goto err;
 393         }
 394
 395         if (BN_is_zero(sig->r)          || BN_is_negative(sig->r) ||
 396             BN_ucmp(sig->r, order) >= 0 || BN_is_zero(sig->s)  ||
 397             BN_is_negative(sig->s)      || BN_ucmp(sig->s, order) >= 0)
 398         {
 399                 ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ECDSA_R_BAD_SIGNATURE);
 400                 ret = 0;        /* signature is invalid */
 401                 goto err;
 402         }
 403         /* calculate tmp1 = inv(S) mod order */
 404         if (!BN_mod_inverse(u2, sig->s, order, ctx))
 405         {
 406                 ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_BN_LIB);
 407                 goto err;
 408         }
 409         /* digest -> m */
 410         i = BN_num_bits(order);
 411         /* Need to truncate digest if it is too long: first truncate whole
 412          * bytes.
 413          */
 414         if (8 * dgst_len > i)
 415                 dgst_len = (i + 7)/8;
 416         if (!BN_bin2bn(dgst, dgst_len, m))
 417         {
 418                 ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_BN_LIB);
 419                 goto err;
 420         }
 421         /* If still too long truncate remaining bits with a shift */
 422         if ((8 * dgst_len > i) && !BN_rshift(m, m, 8 - (i & 0x7)))
 423         {
 424                 ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_BN_LIB);
 425                 goto err;
 426         }
 427         /* u1 = m * tmp mod order */
 428         if (!BN_mod_mul(u1, m, u2, order, ctx))
 429         {
 430                 ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_BN_LIB);
 431                 goto err;
 432         }
 433         /* u2 = r * w mod q */
 434         if (!BN_mod_mul(u2, sig->r, u2, order, ctx))
 435         {
 436                 ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_BN_LIB);
 437                 goto err;
 438         }
 439
 440         if ((point = EC_POINT_new(group)) == NULL)
 441         {
 442                 ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_MALLOC_FAILURE);
 443                 goto err;
 444         }
 445         if (!EC_POINT_mul(group, point, u1, pub_key, u2, ctx))
 446         {
 447                 ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_EC_LIB);
 448                 goto err;
 449         }
 450         if (EC_METHOD_get_field_type(EC_GROUP_method_of(group)) == NID_X9_62_prime_field)
 451         {
 452                 if (!EC_POINT_get_affine_coordinates_GFp(group,
 453                         point, X, NULL, ctx))
 454                 {
 455                         ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_EC_LIB);
 456                         goto err;
 457                 }
 458         }
 459 #ifndef OPENSSL_NO_EC2M
 460         else /* NID_X9_62_characteristic_two_field */
 461         {
 462                 if (!EC_POINT_get_affine_coordinates_GF2m(group,
 463                         point, X, NULL, ctx))
 464                 {
 465                         ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_EC_LIB);
 466                         goto err;
 467                 }
 468         }
 469 #endif
 470         if (!BN_nnmod(u1, X, order, ctx))
 471         {
 472                 ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_BN_LIB);
 473                 goto err;
 474         }
 475         /*  if the signature is correct u1 is equal to sig->r */
 476         ret = (BN_ucmp(u1, sig->r) == 0);
 477 err:
 478         BN_CTX_end(ctx);
 479         BN_CTX_free(ctx);
 480         if (point)
 481                 EC_POINT_free(point);
 482         return ret;
 483 }