crypto/sm2/sm2_pmeth.c

   1 /*
   2  * Copyright 2006-2020 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  * ECDSA low level APIs are deprecated for public use, but still ok for
  12  * internal use.
  13  */
  14 #include "internal/deprecated.h"
  15
  16 #include "internal/cryptlib.h"
  17 #include <openssl/asn1t.h>
  18 #include <openssl/ec.h>
  19 #include <openssl/evp.h>
  20 #include "crypto/evp.h"
  21 #include "crypto/sm2.h"
  22 #include "crypto/sm2err.h"
  23
  24 /* EC pkey context structure */
  25
  26 typedef struct {
  27     /* message digest */
  28     const EVP_MD *md;
  29     /* Distinguishing Identifier, ISO/IEC 15946-3, FIPS 196 */
  30     uint8_t *id;
  31     size_t id_len;
  32     /* id_set indicates if the 'id' field is set (1) or not (0) */
  33     int id_set;
  34 } SM2_PKEY_CTX;
  35
  36 static int pkey_sm2_init(EVP_PKEY_CTX *ctx)
  37 {
  38     SM2_PKEY_CTX *smctx;
  39
  40     if ((smctx = OPENSSL_zalloc(sizeof(*smctx))) == NULL) {
  41         SM2err(SM2_F_PKEY_SM2_INIT, ERR_R_MALLOC_FAILURE);
  42         return 0;
  43     }
  44
  45     ctx->data = smctx;
  46     return 1;
  47 }
  48
  49 static void pkey_sm2_cleanup(EVP_PKEY_CTX *ctx)
  50 {
  51     SM2_PKEY_CTX *smctx = ctx->data;
  52
  53     if (smctx != NULL) {
  54         OPENSSL_free(smctx->id);
  55         OPENSSL_free(smctx);
  56         ctx->data = NULL;
  57     }
  58 }
  59
  60 static int pkey_sm2_copy(EVP_PKEY_CTX *dst, const EVP_PKEY_CTX *src)
  61 {
  62     SM2_PKEY_CTX *dctx, *sctx;
  63
  64     if (!pkey_sm2_init(dst))
  65         return 0;
  66     sctx = src->data;
  67     dctx = dst->data;
  68     if (sctx->id != NULL) {
  69         dctx->id = OPENSSL_malloc(sctx->id_len);
  70         if (dctx->id == NULL) {
  71             SM2err(SM2_F_PKEY_SM2_COPY, ERR_R_MALLOC_FAILURE);
  72             pkey_sm2_cleanup(dst);
  73             return 0;
  74         }
  75         memcpy(dctx->id, sctx->id, sctx->id_len);
  76     }
  77     dctx->id_len = sctx->id_len;
  78     dctx->id_set = sctx->id_set;
  79     dctx->md = sctx->md;
  80
  81     return 1;
  82 }
  83
  84 static int pkey_sm2_sign(EVP_PKEY_CTX *ctx, unsigned char *sig, size_t *siglen,
  85                          const unsigned char *tbs, size_t tbslen)
  86 {
  87     int ret;
  88     unsigned int sltmp;
  89     EC_KEY *ec = ctx->pkey->pkey.ec;
  90     const int sig_sz = ECDSA_size(ctx->pkey->pkey.ec);
  91
  92     if (sig_sz <= 0) {
  93         return 0;
  94     }
  95
  96     if (sig == NULL) {
  97         *siglen = (size_t)sig_sz;
  98         return 1;
  99     }
 100
 101     if (*siglen < (size_t)sig_sz) {
 102         SM2err(SM2_F_PKEY_SM2_SIGN, SM2_R_BUFFER_TOO_SMALL);
 103         return 0;
 104     }
 105
 106     ret = sm2_sign(tbs, tbslen, sig, &sltmp, ec);
 107
 108     if (ret <= 0)
 109         return ret;
 110     *siglen = (size_t)sltmp;
 111     return 1;
 112 }
 113
 114 static int pkey_sm2_verify(EVP_PKEY_CTX *ctx,
 115                            const unsigned char *sig, size_t siglen,
 116                            const unsigned char *tbs, size_t tbslen)
 117 {
 118     EC_KEY *ec = ctx->pkey->pkey.ec;
 119
 120     return sm2_verify(tbs, tbslen, sig, siglen, ec);
 121 }
 122
 123 static int pkey_sm2_encrypt(EVP_PKEY_CTX *ctx,
 124                             unsigned char *out, size_t *outlen,
 125                             const unsigned char *in, size_t inlen)
 126 {
 127     EC_KEY *ec = ctx->pkey->pkey.ec;
 128     SM2_PKEY_CTX *dctx = ctx->data;
 129     const EVP_MD *md = (dctx->md == NULL) ? EVP_sm3() : dctx->md;
 130
 131     if (out == NULL) {
 132         if (!sm2_ciphertext_size(ec, md, inlen, outlen))
 133             return -1;
 134         else
 135             return 1;
 136     }
 137
 138     return sm2_encrypt(ec, md, in, inlen, out, outlen);
 139 }
 140
 141 static int pkey_sm2_decrypt(EVP_PKEY_CTX *ctx,
 142                             unsigned char *out, size_t *outlen,
 143                             const unsigned char *in, size_t inlen)
 144 {
 145     EC_KEY *ec = ctx->pkey->pkey.ec;
 146     SM2_PKEY_CTX *dctx = ctx->data;
 147     const EVP_MD *md = (dctx->md == NULL) ? EVP_sm3() : dctx->md;
 148
 149     if (out == NULL) {
 150         if (!sm2_plaintext_size(ec, md, inlen, outlen))
 151             return -1;
 152         else
 153             return 1;
 154     }
 155
 156     return sm2_decrypt(ec, md, in, inlen, out, outlen);
 157 }
 158
 159 static int pkey_sm2_ctrl(EVP_PKEY_CTX *ctx, int type, int p1, void *p2)
 160 {
 161     SM2_PKEY_CTX *smctx = ctx->data;
 162     uint8_t *tmp_id;
 163
 164     switch (type) {
 165     case EVP_PKEY_CTRL_EC_PARAMGEN_CURVE_NID:
 166         /*
 167          * This control could be removed, which would signal it being
 168          * unsupported.  However, that means that when the caller uses
 169          * the correct curve, it may interpret the unsupported signal
 170          * as an error, so it's better to accept the control, check the
 171          * value and return a corresponding value.
 172          */
 173         if (p1 != NID_sm2) {
 174             SM2err(SM2_F_PKEY_SM2_CTRL, SM2_R_INVALID_CURVE);
 175             return 0;
 176         }
 177         return 1;
 178
 179     case EVP_PKEY_CTRL_MD:
 180         smctx->md = p2;
 181         return 1;
 182
 183     case EVP_PKEY_CTRL_GET_MD:
 184         *(const EVP_MD **)p2 = smctx->md;
 185         return 1;
 186
 187     case EVP_PKEY_CTRL_SET1_ID:
 188         if (p1 > 0) {
 189             tmp_id = OPENSSL_malloc(p1);
 190             if (tmp_id == NULL) {
 191                 SM2err(SM2_F_PKEY_SM2_CTRL, ERR_R_MALLOC_FAILURE);
 192                 return 0;
 193             }
 194             memcpy(tmp_id, p2, p1);
 195             OPENSSL_free(smctx->id);
 196             smctx->id = tmp_id;
 197         } else {
 198             /* set null-ID */
 199             OPENSSL_free(smctx->id);
 200             smctx->id = NULL;
 201         }
 202         smctx->id_len = (size_t)p1;
 203         smctx->id_set = 1;
 204         return 1;
 205
 206     case EVP_PKEY_CTRL_GET1_ID:
 207         memcpy(p2, smctx->id, smctx->id_len);
 208         return 1;
 209
 210     case EVP_PKEY_CTRL_GET1_ID_LEN:
 211         *(size_t *)p2 = smctx->id_len;
 212         return 1;
 213
 214     case EVP_PKEY_CTRL_DIGESTINIT:
 215         /* nothing to be inited, this is to suppress the error... */
 216         return 1;
 217
 218     default:
 219         return -2;
 220     }
 221 }
 222
 223 static int pkey_sm2_ctrl_str(EVP_PKEY_CTX *ctx,
 224                              const char *type, const char *value)
 225 {
 226     uint8_t *hex_id;
 227     long hex_len = 0;
 228     int ret = 0;
 229
 230     if (strcmp(type, "ec_paramgen_curve") == 0) {
 231         int nid = NID_undef;
 232
 233         if (((nid = EC_curve_nist2nid(value)) == NID_undef)
 234             && ((nid = OBJ_sn2nid(value)) == NID_undef)
 235             && ((nid = OBJ_ln2nid(value)) == NID_undef)) {
 236             SM2err(SM2_F_PKEY_SM2_CTRL_STR, SM2_R_INVALID_CURVE);
 237             return 0;
 238         }
 239         return EVP_PKEY_CTX_set_ec_paramgen_curve_nid(ctx, nid);
 240     } else if (strcmp(type, "ec_param_enc") == 0) {
 241         int param_enc;
 242
 243         if (strcmp(value, "explicit") == 0)
 244             param_enc = 0;
 245         else if (strcmp(value, "named_curve") == 0)
 246             param_enc = OPENSSL_EC_NAMED_CURVE;
 247         else
 248             return -2;
 249         return EVP_PKEY_CTX_set_ec_param_enc(ctx, param_enc);
 250     } else if (strcmp(type, "distid") == 0) {
 251         return pkey_sm2_ctrl(ctx, EVP_PKEY_CTRL_SET1_ID,
 252                              (int)strlen(value), (void *)value);
 253     } else if (strcmp(type, "hexdistid") == 0) {
 254         hex_id = OPENSSL_hexstr2buf((const char *)value, &hex_len);
 255         if (hex_id == NULL) {
 256             SM2err(SM2_F_PKEY_SM2_CTRL_STR, ERR_R_PASSED_INVALID_ARGUMENT);
 257             return 0;
 258         }
 259         ret = pkey_sm2_ctrl(ctx, EVP_PKEY_CTRL_SET1_ID, (int)hex_len,
 260                             (void *)hex_id);
 261         OPENSSL_free(hex_id);
 262         return ret;
 263     }
 264
 265     return -2;
 266 }
 267
 268 static int pkey_sm2_digest_custom(EVP_PKEY_CTX *ctx, EVP_MD_CTX *mctx)
 269 {
 270     uint8_t z[EVP_MAX_MD_SIZE];
 271     SM2_PKEY_CTX *smctx = ctx->data;
 272     EC_KEY *ec = ctx->pkey->pkey.ec;
 273     const EVP_MD *md = EVP_MD_CTX_md(mctx);
 274     int mdlen = EVP_MD_size(md);
 275
 276     if (!smctx->id_set) {
 277         /*
 278          * An ID value must be set. The specifications are not clear whether a
 279          * NULL is allowed. We only allow it if set explicitly for maximum
 280          * flexibility.
 281          */
 282         SM2err(SM2_F_PKEY_SM2_DIGEST_CUSTOM, SM2_R_ID_NOT_SET);
 283         return 0;
 284     }
 285
 286     if (mdlen < 0) {
 287         SM2err(SM2_F_PKEY_SM2_DIGEST_CUSTOM, SM2_R_INVALID_DIGEST);
 288         return 0;
 289     }
 290
 291     /* get hashed prefix 'z' of tbs message */
 292     if (!sm2_compute_z_digest(z, md, smctx->id, smctx->id_len, ec))
 293         return 0;
 294
 295     return EVP_DigestUpdate(mctx, z, (size_t)mdlen);
 296 }
 297
 298 static int pkey_sm2_paramgen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey)
 299 {
 300     EC_KEY *ec = NULL;
 301     int ret;
 302
 303     ec = EC_KEY_new_by_curve_name(NID_sm2);
 304     if (ec == NULL)
 305         return 0;
 306     if (!ossl_assert(ret = EVP_PKEY_assign_EC_KEY(pkey, ec)))
 307         EC_KEY_free(ec);
 308     return ret;
 309 }
 310
 311 static int pkey_sm2_keygen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey)
 312 {
 313     EC_KEY *ec = NULL;
 314
 315     ec = EC_KEY_new_by_curve_name(NID_sm2);
 316     if (ec == NULL)
 317         return 0;
 318     if (!ossl_assert(EVP_PKEY_assign_EC_KEY(pkey, ec))) {
 319         EC_KEY_free(ec);
 320         return 0;
 321     }
 322     /* Note: if error is returned, we count on caller to free pkey->pkey.ec */
 323     if (ctx->pkey != NULL
 324         && !EVP_PKEY_copy_parameters(pkey, ctx->pkey))
 325         return 0;
 326
 327     return EC_KEY_generate_key(ec);
 328 }
 329
 330 static const EVP_PKEY_METHOD sm2_pkey_meth = {
 331     EVP_PKEY_SM2,
 332     0,
 333     pkey_sm2_init,
 334     pkey_sm2_copy,
 335     pkey_sm2_cleanup,
 336
 337     0,
 338     pkey_sm2_paramgen,
 339
 340     0,
 341     pkey_sm2_keygen,
 342
 343     0,
 344     pkey_sm2_sign,
 345
 346     0,
 347     pkey_sm2_verify,
 348
 349     0, 0,
 350
 351     0, 0, 0, 0,
 352
 353     0,
 354     pkey_sm2_encrypt,
 355
 356     0,
 357     pkey_sm2_decrypt,
 358
 359     0,
 360     0,
 361     pkey_sm2_ctrl,
 362     pkey_sm2_ctrl_str,
 363
 364     0, 0,
 365
 366     0, 0, 0,
 367
 368     pkey_sm2_digest_custom
 369 };
 370
 371 const EVP_PKEY_METHOD *sm2_pkey_method(void)
 372 {
 373     return &sm2_pkey_meth;
 374 }