providers/implementations/signature/dsa.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  * DSA low level APIs are deprecated for public use, but still ok for
  12  * internal use.
  13  */
  14 #include "internal/deprecated.h"
  15
  16 #include <string.h>
  17
  18 #include <openssl/crypto.h>
  19 #include <openssl/core_numbers.h>
  20 #include <openssl/core_names.h>
  21 #include <openssl/err.h>
  22 #include <openssl/dsa.h>
  23 #include <openssl/params.h>
  24 #include <openssl/evp.h>
  25 #include <openssl/err.h>
  26 #include "internal/nelem.h"
  27 #include "internal/sizes.h"
  28 #include "internal/cryptlib.h"
  29 #include "prov/providercommonerr.h"
  30 #include "prov/implementations.h"
  31 #include "prov/providercommonerr.h"
  32 #include "prov/provider_ctx.h"
  33 #include "crypto/dsa.h"
  34 #include "prov/der_dsa.h"
  35
  36 static OSSL_OP_signature_newctx_fn dsa_newctx;
  37 static OSSL_OP_signature_sign_init_fn dsa_signature_init;
  38 static OSSL_OP_signature_verify_init_fn dsa_signature_init;
  39 static OSSL_OP_signature_sign_fn dsa_sign;
  40 static OSSL_OP_signature_verify_fn dsa_verify;
  41 static OSSL_OP_signature_digest_sign_init_fn dsa_digest_signverify_init;
  42 static OSSL_OP_signature_digest_sign_update_fn dsa_digest_signverify_update;
  43 static OSSL_OP_signature_digest_sign_final_fn dsa_digest_sign_final;
  44 static OSSL_OP_signature_digest_verify_init_fn dsa_digest_signverify_init;
  45 static OSSL_OP_signature_digest_verify_update_fn dsa_digest_signverify_update;
  46 static OSSL_OP_signature_digest_verify_final_fn dsa_digest_verify_final;
  47 static OSSL_OP_signature_freectx_fn dsa_freectx;
  48 static OSSL_OP_signature_dupctx_fn dsa_dupctx;
  49 static OSSL_OP_signature_get_ctx_params_fn dsa_get_ctx_params;
  50 static OSSL_OP_signature_gettable_ctx_params_fn dsa_gettable_ctx_params;
  51 static OSSL_OP_signature_set_ctx_params_fn dsa_set_ctx_params;
  52 static OSSL_OP_signature_settable_ctx_params_fn dsa_settable_ctx_params;
  53 static OSSL_OP_signature_get_ctx_md_params_fn dsa_get_ctx_md_params;
  54 static OSSL_OP_signature_gettable_ctx_md_params_fn dsa_gettable_ctx_md_params;
  55 static OSSL_OP_signature_set_ctx_md_params_fn dsa_set_ctx_md_params;
  56 static OSSL_OP_signature_settable_ctx_md_params_fn dsa_settable_ctx_md_params;
  57
  58 /*
  59  * What's passed as an actual key is defined by the KEYMGMT interface.
  60  * We happen to know that our KEYMGMT simply passes DSA structures, so
  61  * we use that here too.
  62  */
  63
  64 typedef struct {
  65     OPENSSL_CTX *libctx;
  66     DSA *dsa;
  67
  68     /*
  69      * Flag to determine if the hash function can be changed (1) or not (0)
  70      * Because it's dangerous to change during a DigestSign or DigestVerify
  71      * operation, this flag is cleared by their Init function, and set again
  72      * by their Final function.
  73      */
  74     unsigned int flag_allow_md : 1;
  75
  76     char mdname[OSSL_MAX_NAME_SIZE];
  77
  78     /* The Algorithm Identifier of the combined signature algorithm */
  79     unsigned char aid_buf[OSSL_MAX_ALGORITHM_ID_SIZE];
  80     unsigned char *aid;
  81     size_t  aid_len;
  82
  83     /* main digest */
  84     EVP_MD *md;
  85     EVP_MD_CTX *mdctx;
  86     size_t mdsize;
  87 } PROV_DSA_CTX;
  88
  89 static size_t dsa_get_md_size(const PROV_DSA_CTX *pdsactx)
  90 {
  91     if (pdsactx->md != NULL)
  92         return EVP_MD_size(pdsactx->md);
  93     return 0;
  94 }
  95
  96 static int dsa_get_md_nid(const EVP_MD *md)
  97 {
  98     /*
  99      * Because the DSA library deals with NIDs, we need to translate.
 100      * We do so using EVP_MD_is_a(), and therefore need a name to NID
 101      * map.
 102      */
 103     static const OSSL_ITEM name_to_nid[] = {
 104         { NID_sha1,   OSSL_DIGEST_NAME_SHA1   },
 105         { NID_sha224, OSSL_DIGEST_NAME_SHA2_224 },
 106         { NID_sha256, OSSL_DIGEST_NAME_SHA2_256 },
 107         { NID_sha384, OSSL_DIGEST_NAME_SHA2_384 },
 108         { NID_sha512, OSSL_DIGEST_NAME_SHA2_512 },
 109         { NID_sha3_224, OSSL_DIGEST_NAME_SHA3_224 },
 110         { NID_sha3_256, OSSL_DIGEST_NAME_SHA3_256 },
 111         { NID_sha3_384, OSSL_DIGEST_NAME_SHA3_384 },
 112         { NID_sha3_512, OSSL_DIGEST_NAME_SHA3_512 },
 113     };
 114     size_t i;
 115     int mdnid = NID_undef;
 116
 117     if (md == NULL)
 118         goto end;
 119
 120     for (i = 0; i < OSSL_NELEM(name_to_nid); i++) {
 121         if (EVP_MD_is_a(md, name_to_nid[i].ptr)) {
 122             mdnid = (int)name_to_nid[i].id;
 123             break;
 124         }
 125     }
 126
 127     if (mdnid == NID_undef)
 128         ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_DIGEST);
 129
 130  end:
 131     return mdnid;
 132 }
 133
 134 static void *dsa_newctx(void *provctx)
 135 {
 136     PROV_DSA_CTX *pdsactx = OPENSSL_zalloc(sizeof(PROV_DSA_CTX));
 137
 138     if (pdsactx == NULL)
 139         return NULL;
 140
 141     pdsactx->libctx = PROV_LIBRARY_CONTEXT_OF(provctx);
 142     pdsactx->flag_allow_md = 1;
 143     return pdsactx;
 144 }
 145
 146 static int dsa_setup_md(PROV_DSA_CTX *ctx,
 147                         const char *mdname, const char *mdprops)
 148 {
 149     if (mdname != NULL) {
 150         EVP_MD *md = EVP_MD_fetch(ctx->libctx, mdname, mdprops);
 151         int md_nid = dsa_get_md_nid(md);
 152         WPACKET pkt;
 153
 154         if (md == NULL || md_nid == NID_undef) {
 155             EVP_MD_free(md);
 156             return 0;
 157         }
 158
 159         EVP_MD_CTX_free(ctx->mdctx);
 160         EVP_MD_free(ctx->md);
 161
 162         /*
 163          * TODO(3.0) Should we care about DER writing errors?
 164          * All it really means is that for some reason, there's no
 165          * AlgorithmIdentifier to be had, but the operation itself is
 166          * still valid, just as long as it's not used to construct
 167          * anything that needs an AlgorithmIdentifier.
 168          */
 169         ctx->aid_len = 0;
 170         if (WPACKET_init_der(&pkt, ctx->aid_buf, sizeof(ctx->aid_buf))
 171             && DER_w_algorithmIdentifier_DSA_with(&pkt, -1, ctx->dsa, md_nid)
 172             && WPACKET_finish(&pkt)) {
 173             WPACKET_get_total_written(&pkt, &ctx->aid_len);
 174             ctx->aid = WPACKET_get_curr(&pkt);
 175         }
 176         WPACKET_cleanup(&pkt);
 177
 178         ctx->mdctx = NULL;
 179         ctx->md = md;
 180         OPENSSL_strlcpy(ctx->mdname, mdname, sizeof(ctx->mdname));
 181     }
 182     return 1;
 183 }
 184
 185 static int dsa_signature_init(void *vpdsactx, void *vdsa)
 186 {
 187     PROV_DSA_CTX *pdsactx = (PROV_DSA_CTX *)vpdsactx;
 188
 189     if (pdsactx == NULL || vdsa == NULL || !DSA_up_ref(vdsa))
 190         return 0;
 191     DSA_free(pdsactx->dsa);
 192     pdsactx->dsa = vdsa;
 193     return 1;
 194 }
 195
 196 static int dsa_sign(void *vpdsactx, unsigned char *sig, size_t *siglen,
 197                     size_t sigsize, const unsigned char *tbs, size_t tbslen)
 198 {
 199     PROV_DSA_CTX *pdsactx = (PROV_DSA_CTX *)vpdsactx;
 200     int ret;
 201     unsigned int sltmp;
 202     size_t dsasize = DSA_size(pdsactx->dsa);
 203     size_t mdsize = dsa_get_md_size(pdsactx);
 204
 205     if (sig == NULL) {
 206         *siglen = dsasize;
 207         return 1;
 208     }
 209
 210     if (sigsize < (size_t)dsasize)
 211         return 0;
 212
 213     if (mdsize != 0 && tbslen != mdsize)
 214         return 0;
 215
 216     ret = dsa_sign_int(0, tbs, tbslen, sig, &sltmp, pdsactx->dsa);
 217     if (ret <= 0)
 218         return 0;
 219
 220     *siglen = sltmp;
 221     return 1;
 222 }
 223
 224 static int dsa_verify(void *vpdsactx, const unsigned char *sig, size_t siglen,
 225                       const unsigned char *tbs, size_t tbslen)
 226 {
 227     PROV_DSA_CTX *pdsactx = (PROV_DSA_CTX *)vpdsactx;
 228     size_t mdsize = dsa_get_md_size(pdsactx);
 229
 230     if (mdsize != 0 && tbslen != mdsize)
 231         return 0;
 232
 233     return DSA_verify(0, tbs, tbslen, sig, siglen, pdsactx->dsa);
 234 }
 235
 236 static int dsa_digest_signverify_init(void *vpdsactx, const char *mdname,
 237                                       const char *props, void *vdsa)
 238 {
 239     PROV_DSA_CTX *pdsactx = (PROV_DSA_CTX *)vpdsactx;
 240
 241     pdsactx->flag_allow_md = 0;
 242     if (!dsa_signature_init(vpdsactx, vdsa))
 243         return 0;
 244
 245     if (!dsa_setup_md(pdsactx, mdname, props))
 246         return 0;
 247
 248     pdsactx->mdctx = EVP_MD_CTX_new();
 249     if (pdsactx->mdctx == NULL)
 250         goto error;
 251
 252     if (!EVP_DigestInit_ex(pdsactx->mdctx, pdsactx->md, NULL))
 253         goto error;
 254
 255     return 1;
 256
 257  error:
 258     EVP_MD_CTX_free(pdsactx->mdctx);
 259     EVP_MD_free(pdsactx->md);
 260     pdsactx->mdctx = NULL;
 261     pdsactx->md = NULL;
 262     return 0;
 263 }
 264
 265 int dsa_digest_signverify_update(void *vpdsactx, const unsigned char *data,
 266                                  size_t datalen)
 267 {
 268     PROV_DSA_CTX *pdsactx = (PROV_DSA_CTX *)vpdsactx;
 269
 270     if (pdsactx == NULL || pdsactx->mdctx == NULL)
 271         return 0;
 272
 273     return EVP_DigestUpdate(pdsactx->mdctx, data, datalen);
 274 }
 275
 276 int dsa_digest_sign_final(void *vpdsactx, unsigned char *sig, size_t *siglen,
 277                           size_t sigsize)
 278 {
 279     PROV_DSA_CTX *pdsactx = (PROV_DSA_CTX *)vpdsactx;
 280     unsigned char digest[EVP_MAX_MD_SIZE];
 281     unsigned int dlen = 0;
 282
 283     if (pdsactx == NULL || pdsactx->mdctx == NULL)
 284         return 0;
 285
 286     /*
 287      * If sig is NULL then we're just finding out the sig size. Other fields
 288      * are ignored. Defer to dsa_sign.
 289      */
 290     if (sig != NULL) {
 291         /*
 292          * TODO(3.0): There is the possibility that some externally provided
 293          * digests exceed EVP_MAX_MD_SIZE. We should probably handle that somehow -
 294          * but that problem is much larger than just in DSA.
 295          */
 296         if (!EVP_DigestFinal_ex(pdsactx->mdctx, digest, &dlen))
 297             return 0;
 298     }
 299
 300     pdsactx->flag_allow_md = 1;
 301
 302     return dsa_sign(vpdsactx, sig, siglen, sigsize, digest, (size_t)dlen);
 303 }
 304
 305
 306 int dsa_digest_verify_final(void *vpdsactx, const unsigned char *sig,
 307                             size_t siglen)
 308 {
 309     PROV_DSA_CTX *pdsactx = (PROV_DSA_CTX *)vpdsactx;
 310     unsigned char digest[EVP_MAX_MD_SIZE];
 311     unsigned int dlen = 0;
 312
 313     if (pdsactx == NULL || pdsactx->mdctx == NULL)
 314         return 0;
 315
 316     /*
 317      * TODO(3.0): There is the possibility that some externally provided
 318      * digests exceed EVP_MAX_MD_SIZE. We should probably handle that somehow -
 319      * but that problem is much larger than just in DSA.
 320      */
 321     if (!EVP_DigestFinal_ex(pdsactx->mdctx, digest, &dlen))
 322         return 0;
 323
 324     pdsactx->flag_allow_md = 1;
 325
 326     return dsa_verify(vpdsactx, sig, siglen, digest, (size_t)dlen);
 327 }
 328
 329 static void dsa_freectx(void *vpdsactx)
 330 {
 331     PROV_DSA_CTX *pdsactx = (PROV_DSA_CTX *)vpdsactx;
 332
 333     DSA_free(pdsactx->dsa);
 334     EVP_MD_CTX_free(pdsactx->mdctx);
 335     EVP_MD_free(pdsactx->md);
 336
 337     OPENSSL_free(pdsactx);
 338 }
 339
 340 static void *dsa_dupctx(void *vpdsactx)
 341 {
 342     PROV_DSA_CTX *srcctx = (PROV_DSA_CTX *)vpdsactx;
 343     PROV_DSA_CTX *dstctx;
 344
 345     dstctx = OPENSSL_zalloc(sizeof(*srcctx));
 346     if (dstctx == NULL)
 347         return NULL;
 348
 349     *dstctx = *srcctx;
 350     dstctx->dsa = NULL;
 351     dstctx->md = NULL;
 352     dstctx->mdctx = NULL;
 353
 354     if (srcctx->dsa != NULL && !DSA_up_ref(srcctx->dsa))
 355         goto err;
 356     dstctx->dsa = srcctx->dsa;
 357
 358     if (srcctx->md != NULL && !EVP_MD_up_ref(srcctx->md))
 359         goto err;
 360     dstctx->md = srcctx->md;
 361
 362     if (srcctx->mdctx != NULL) {
 363         dstctx->mdctx = EVP_MD_CTX_new();
 364         if (dstctx->mdctx == NULL
 365                 || !EVP_MD_CTX_copy_ex(dstctx->mdctx, srcctx->mdctx))
 366             goto err;
 367     }
 368
 369     return dstctx;
 370  err:
 371     dsa_freectx(dstctx);
 372     return NULL;
 373 }
 374
 375 static int dsa_get_ctx_params(void *vpdsactx, OSSL_PARAM *params)
 376 {
 377     PROV_DSA_CTX *pdsactx = (PROV_DSA_CTX *)vpdsactx;
 378     OSSL_PARAM *p;
 379
 380     if (pdsactx == NULL || params == NULL)
 381         return 0;
 382
 383     p = OSSL_PARAM_locate(params, OSSL_SIGNATURE_PARAM_ALGORITHM_ID);
 384     if (p != NULL
 385         && !OSSL_PARAM_set_octet_string(p, pdsactx->aid, pdsactx->aid_len))
 386         return 0;
 387
 388     p = OSSL_PARAM_locate(params, OSSL_SIGNATURE_PARAM_DIGEST);
 389     if (p != NULL && !OSSL_PARAM_set_utf8_string(p, pdsactx->mdname))
 390         return 0;
 391
 392     return 1;
 393 }
 394
 395 static const OSSL_PARAM known_gettable_ctx_params[] = {
 396     OSSL_PARAM_octet_string(OSSL_SIGNATURE_PARAM_ALGORITHM_ID, NULL, 0),
 397     OSSL_PARAM_utf8_string(OSSL_SIGNATURE_PARAM_DIGEST, NULL, 0),
 398     OSSL_PARAM_END
 399 };
 400
 401 static const OSSL_PARAM *dsa_gettable_ctx_params(void)
 402 {
 403     return known_gettable_ctx_params;
 404 }
 405
 406 static int dsa_set_ctx_params(void *vpdsactx, const OSSL_PARAM params[])
 407 {
 408     PROV_DSA_CTX *pdsactx = (PROV_DSA_CTX *)vpdsactx;
 409     const OSSL_PARAM *p;
 410
 411     if (pdsactx == NULL || params == NULL)
 412         return 0;
 413
 414     p = OSSL_PARAM_locate_const(params, OSSL_SIGNATURE_PARAM_DIGEST);
 415     /* Not allowed during certain operations */
 416     if (p != NULL && !pdsactx->flag_allow_md)
 417         return 0;
 418     if (p != NULL) {
 419         char mdname[OSSL_MAX_NAME_SIZE] = "", *pmdname = mdname;
 420         char mdprops[OSSL_MAX_PROPQUERY_SIZE] = "", *pmdprops = mdprops;
 421         const OSSL_PARAM *propsp =
 422             OSSL_PARAM_locate_const(params,
 423                                     OSSL_SIGNATURE_PARAM_PROPERTIES);
 424
 425         if (!OSSL_PARAM_get_utf8_string(p, &pmdname, sizeof(mdname)))
 426             return 0;
 427         if (propsp != NULL
 428             && !OSSL_PARAM_get_utf8_string(propsp, &pmdprops, sizeof(mdprops)))
 429             return 0;
 430         if (!dsa_setup_md(pdsactx, mdname, mdprops))
 431             return 0;
 432     }
 433
 434     return 1;
 435 }
 436
 437 static const OSSL_PARAM known_settable_ctx_params[] = {
 438     OSSL_PARAM_utf8_string(OSSL_SIGNATURE_PARAM_DIGEST, NULL, 0),
 439     OSSL_PARAM_END
 440 };
 441
 442 static const OSSL_PARAM *dsa_settable_ctx_params(void)
 443 {
 444     /*
 445      * TODO(3.0): Should this function return a different set of settable ctx
 446      * params if the ctx is being used for a DigestSign/DigestVerify? In that
 447      * case it is not allowed to set the digest size/digest name because the
 448      * digest is explicitly set as part of the init.
 449      */
 450     return known_settable_ctx_params;
 451 }
 452
 453 static int dsa_get_ctx_md_params(void *vpdsactx, OSSL_PARAM *params)
 454 {
 455     PROV_DSA_CTX *pdsactx = (PROV_DSA_CTX *)vpdsactx;
 456
 457     if (pdsactx->mdctx == NULL)
 458         return 0;
 459
 460     return EVP_MD_CTX_get_params(pdsactx->mdctx, params);
 461 }
 462
 463 static const OSSL_PARAM *dsa_gettable_ctx_md_params(void *vpdsactx)
 464 {
 465     PROV_DSA_CTX *pdsactx = (PROV_DSA_CTX *)vpdsactx;
 466
 467     if (pdsactx->md == NULL)
 468         return 0;
 469
 470     return EVP_MD_gettable_ctx_params(pdsactx->md);
 471 }
 472
 473 static int dsa_set_ctx_md_params(void *vpdsactx, const OSSL_PARAM params[])
 474 {
 475     PROV_DSA_CTX *pdsactx = (PROV_DSA_CTX *)vpdsactx;
 476
 477     if (pdsactx->mdctx == NULL)
 478         return 0;
 479
 480     return EVP_MD_CTX_set_params(pdsactx->mdctx, params);
 481 }
 482
 483 static const OSSL_PARAM *dsa_settable_ctx_md_params(void *vpdsactx)
 484 {
 485     PROV_DSA_CTX *pdsactx = (PROV_DSA_CTX *)vpdsactx;
 486
 487     if (pdsactx->md == NULL)
 488         return 0;
 489
 490     return EVP_MD_settable_ctx_params(pdsactx->md);
 491 }
 492
 493 const OSSL_DISPATCH dsa_signature_functions[] = {
 494     { OSSL_FUNC_SIGNATURE_NEWCTX, (void (*)(void))dsa_newctx },
 495     { OSSL_FUNC_SIGNATURE_SIGN_INIT, (void (*)(void))dsa_signature_init },
 496     { OSSL_FUNC_SIGNATURE_SIGN, (void (*)(void))dsa_sign },
 497     { OSSL_FUNC_SIGNATURE_VERIFY_INIT, (void (*)(void))dsa_signature_init },
 498     { OSSL_FUNC_SIGNATURE_VERIFY, (void (*)(void))dsa_verify },
 499     { OSSL_FUNC_SIGNATURE_DIGEST_SIGN_INIT,
 500       (void (*)(void))dsa_digest_signverify_init },
 501     { OSSL_FUNC_SIGNATURE_DIGEST_SIGN_UPDATE,
 502       (void (*)(void))dsa_digest_signverify_update },
 503     { OSSL_FUNC_SIGNATURE_DIGEST_SIGN_FINAL,
 504       (void (*)(void))dsa_digest_sign_final },
 505     { OSSL_FUNC_SIGNATURE_DIGEST_VERIFY_INIT,
 506       (void (*)(void))dsa_digest_signverify_init },
 507     { OSSL_FUNC_SIGNATURE_DIGEST_VERIFY_UPDATE,
 508       (void (*)(void))dsa_digest_signverify_update },
 509     { OSSL_FUNC_SIGNATURE_DIGEST_VERIFY_FINAL,
 510       (void (*)(void))dsa_digest_verify_final },
 511     { OSSL_FUNC_SIGNATURE_FREECTX, (void (*)(void))dsa_freectx },
 512     { OSSL_FUNC_SIGNATURE_DUPCTX, (void (*)(void))dsa_dupctx },
 513     { OSSL_FUNC_SIGNATURE_GET_CTX_PARAMS, (void (*)(void))dsa_get_ctx_params },
 514     { OSSL_FUNC_SIGNATURE_GETTABLE_CTX_PARAMS,
 515       (void (*)(void))dsa_gettable_ctx_params },
 516     { OSSL_FUNC_SIGNATURE_SET_CTX_PARAMS, (void (*)(void))dsa_set_ctx_params },
 517     { OSSL_FUNC_SIGNATURE_SETTABLE_CTX_PARAMS,
 518       (void (*)(void))dsa_settable_ctx_params },
 519     { OSSL_FUNC_SIGNATURE_GET_CTX_MD_PARAMS,
 520       (void (*)(void))dsa_get_ctx_md_params },
 521     { OSSL_FUNC_SIGNATURE_GETTABLE_CTX_MD_PARAMS,
 522       (void (*)(void))dsa_gettable_ctx_md_params },
 523     { OSSL_FUNC_SIGNATURE_SET_CTX_MD_PARAMS,
 524       (void (*)(void))dsa_set_ctx_md_params },
 525     { OSSL_FUNC_SIGNATURE_SETTABLE_CTX_MD_PARAMS,
 526       (void (*)(void))dsa_settable_ctx_md_params },
 527     { 0, NULL }
 528 };