lib/libcrypto/ec/ec_pmeth.c

   1 /* $OpenBSD: ec_pmeth.c,v 1.10 2017/01/29 17:49:23 beck Exp $ */
   2 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
   3  * project 2006.
   4  */
   5 /* ====================================================================
   6  * Copyright (c) 2006 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  *    licensing@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 <stdio.h>
  60 #include <string.h>
  61
  62 #include <openssl/asn1t.h>
  63 #include <openssl/ec.h>
  64 #include <openssl/ecdsa.h>
  65 #include <openssl/err.h>
  66 #include <openssl/evp.h>
  67 #include <openssl/x509.h>
  68
  69 #include "evp_locl.h"
  70
  71 /* EC pkey context structure */
  72
  73 typedef struct {
  74         /* Key and paramgen group */
  75         EC_GROUP *gen_group;
  76         /* message digest */
  77         const EVP_MD *md;
  78 } EC_PKEY_CTX;
  79
  80 static int
  81 pkey_ec_init(EVP_PKEY_CTX * ctx)
  82 {
  83         EC_PKEY_CTX *dctx;
  84         dctx = malloc(sizeof(EC_PKEY_CTX));
  85         if (!dctx)
  86                 return 0;
  87         dctx->gen_group = NULL;
  88         dctx->md = NULL;
  89
  90         ctx->data = dctx;
  91
  92         return 1;
  93 }
  94
  95 static int
  96 pkey_ec_copy(EVP_PKEY_CTX * dst, EVP_PKEY_CTX * src)
  97 {
  98         EC_PKEY_CTX *dctx, *sctx;
  99         if (!pkey_ec_init(dst))
 100                 return 0;
 101         sctx = src->data;
 102         dctx = dst->data;
 103         if (sctx->gen_group) {
 104                 dctx->gen_group = EC_GROUP_dup(sctx->gen_group);
 105                 if (!dctx->gen_group)
 106                         return 0;
 107         }
 108         dctx->md = sctx->md;
 109         return 1;
 110 }
 111
 112 static void
 113 pkey_ec_cleanup(EVP_PKEY_CTX * ctx)
 114 {
 115         EC_PKEY_CTX *dctx = ctx->data;
 116         if (dctx) {
 117                 EC_GROUP_free(dctx->gen_group);
 118                 free(dctx);
 119         }
 120 }
 121
 122 static int
 123 pkey_ec_sign(EVP_PKEY_CTX * ctx, unsigned char *sig, size_t * siglen,
 124     const unsigned char *tbs, size_t tbslen)
 125 {
 126         int ret, type;
 127         unsigned int sltmp;
 128         EC_PKEY_CTX *dctx = ctx->data;
 129         EC_KEY *ec = ctx->pkey->pkey.ec;
 130
 131         if (!sig) {
 132                 *siglen = ECDSA_size(ec);
 133                 return 1;
 134         } else if (*siglen < (size_t) ECDSA_size(ec)) {
 135                 ECerror(EC_R_BUFFER_TOO_SMALL);
 136                 return 0;
 137         }
 138         if (dctx->md)
 139                 type = EVP_MD_type(dctx->md);
 140         else
 141                 type = NID_sha1;
 142
 143
 144         ret = ECDSA_sign(type, tbs, tbslen, sig, &sltmp, ec);
 145
 146         if (ret <= 0)
 147                 return ret;
 148         *siglen = (size_t) sltmp;
 149         return 1;
 150 }
 151
 152 static int
 153 pkey_ec_verify(EVP_PKEY_CTX * ctx,
 154     const unsigned char *sig, size_t siglen,
 155     const unsigned char *tbs, size_t tbslen)
 156 {
 157         int ret, type;
 158         EC_PKEY_CTX *dctx = ctx->data;
 159         EC_KEY *ec = ctx->pkey->pkey.ec;
 160
 161         if (dctx->md)
 162                 type = EVP_MD_type(dctx->md);
 163         else
 164                 type = NID_sha1;
 165
 166         ret = ECDSA_verify(type, tbs, tbslen, sig, siglen, ec);
 167
 168         return ret;
 169 }
 170
 171 static int
 172 pkey_ec_derive(EVP_PKEY_CTX * ctx, unsigned char *key, size_t * keylen)
 173 {
 174         int ret;
 175         size_t outlen;
 176         const EC_POINT *pubkey = NULL;
 177         if (!ctx->pkey || !ctx->peerkey) {
 178                 ECerror(EC_R_KEYS_NOT_SET);
 179                 return 0;
 180         }
 181         if (!key) {
 182                 const EC_GROUP *group;
 183                 group = EC_KEY_get0_group(ctx->pkey->pkey.ec);
 184                 *keylen = (EC_GROUP_get_degree(group) + 7) / 8;
 185                 return 1;
 186         }
 187         pubkey = EC_KEY_get0_public_key(ctx->peerkey->pkey.ec);
 188
 189         /*
 190          * NB: unlike PKCS#3 DH, if *outlen is less than maximum size this is
 191          * not an error, the result is truncated.
 192          */
 193
 194         outlen = *keylen;
 195
 196         ret = ECDH_compute_key(key, outlen, pubkey, ctx->pkey->pkey.ec, 0);
 197         if (ret < 0)
 198                 return ret;
 199         *keylen = ret;
 200         return 1;
 201 }
 202
 203 static int
 204 pkey_ec_ctrl(EVP_PKEY_CTX * ctx, int type, int p1, void *p2)
 205 {
 206         EC_PKEY_CTX *dctx = ctx->data;
 207         EC_GROUP *group;
 208         switch (type) {
 209         case EVP_PKEY_CTRL_EC_PARAMGEN_CURVE_NID:
 210                 group = EC_GROUP_new_by_curve_name(p1);
 211                 if (group == NULL) {
 212                         ECerror(EC_R_INVALID_CURVE);
 213                         return 0;
 214                 }
 215                 EC_GROUP_free(dctx->gen_group);
 216                 dctx->gen_group = group;
 217                 return 1;
 218
 219         case EVP_PKEY_CTRL_MD:
 220                 if (EVP_MD_type((const EVP_MD *) p2) != NID_sha1 &&
 221                     EVP_MD_type((const EVP_MD *) p2) != NID_ecdsa_with_SHA1 &&
 222                     EVP_MD_type((const EVP_MD *) p2) != NID_sha224 &&
 223                     EVP_MD_type((const EVP_MD *) p2) != NID_sha256 &&
 224                     EVP_MD_type((const EVP_MD *) p2) != NID_sha384 &&
 225                     EVP_MD_type((const EVP_MD *) p2) != NID_sha512) {
 226                         ECerror(EC_R_INVALID_DIGEST_TYPE);
 227                         return 0;
 228                 }
 229                 dctx->md = p2;
 230                 return 1;
 231
 232         case EVP_PKEY_CTRL_PEER_KEY:
 233                 /* Default behaviour is OK */
 234         case EVP_PKEY_CTRL_DIGESTINIT:
 235         case EVP_PKEY_CTRL_PKCS7_SIGN:
 236         case EVP_PKEY_CTRL_CMS_SIGN:
 237                 return 1;
 238
 239         default:
 240                 return -2;
 241
 242         }
 243 }
 244
 245 static int
 246 pkey_ec_ctrl_str(EVP_PKEY_CTX * ctx,
 247     const char *type, const char *value)
 248 {
 249         if (!strcmp(type, "ec_paramgen_curve")) {
 250                 int nid;
 251                 nid = EC_curve_nist2nid(value);
 252                 if (nid == NID_undef)
 253                         nid = OBJ_sn2nid(value);
 254                 if (nid == NID_undef)
 255                         nid = OBJ_ln2nid(value);
 256                 if (nid == NID_undef) {
 257                         ECerror(EC_R_INVALID_CURVE);
 258                         return 0;
 259                 }
 260                 return EVP_PKEY_CTX_set_ec_paramgen_curve_nid(ctx, nid);
 261         }
 262         return -2;
 263 }
 264
 265 static int
 266 pkey_ec_paramgen(EVP_PKEY_CTX * ctx, EVP_PKEY * pkey)
 267 {
 268         EC_KEY *ec = NULL;
 269         EC_PKEY_CTX *dctx = ctx->data;
 270         int ret = 0;
 271         if (dctx->gen_group == NULL) {
 272                 ECerror(EC_R_NO_PARAMETERS_SET);
 273                 return 0;
 274         }
 275         ec = EC_KEY_new();
 276         if (!ec)
 277                 return 0;
 278         ret = EC_KEY_set_group(ec, dctx->gen_group);
 279         if (ret)
 280                 EVP_PKEY_assign_EC_KEY(pkey, ec);
 281         else
 282                 EC_KEY_free(ec);
 283         return ret;
 284 }
 285
 286 static int
 287 pkey_ec_keygen(EVP_PKEY_CTX * ctx, EVP_PKEY * pkey)
 288 {
 289         EC_KEY *ec = NULL;
 290         if (ctx->pkey == NULL) {
 291                 ECerror(EC_R_NO_PARAMETERS_SET);
 292                 return 0;
 293         }
 294         ec = EC_KEY_new();
 295         if (!ec)
 296                 return 0;
 297         EVP_PKEY_assign_EC_KEY(pkey, ec);
 298         /* Note: if error return, pkey is freed by parent routine */
 299         if (!EVP_PKEY_copy_parameters(pkey, ctx->pkey))
 300                 return 0;
 301         return EC_KEY_generate_key(pkey->pkey.ec);
 302 }
 303
 304 const EVP_PKEY_METHOD ec_pkey_meth = {
 305         .pkey_id = EVP_PKEY_EC,
 306
 307         .init = pkey_ec_init,
 308         .copy = pkey_ec_copy,
 309         .cleanup = pkey_ec_cleanup,
 310
 311         .paramgen = pkey_ec_paramgen,
 312
 313         .keygen = pkey_ec_keygen,
 314
 315         .sign = pkey_ec_sign,
 316
 317         .verify = pkey_ec_verify,
 318
 319         .derive = pkey_ec_derive,
 320
 321         .ctrl = pkey_ec_ctrl,
 322         .ctrl_str = pkey_ec_ctrl_str
 323 };