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_dispatch.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_FUNC_signature_newctx_fn dsa_newctx;
  37 static OSSL_FUNC_signature_sign_init_fn dsa_signature_init;
  38 static OSSL_FUNC_signature_verify_init_fn dsa_signature_init;
  39 static OSSL_FUNC_signature_sign_fn dsa_sign;
  40 static OSSL_FUNC_signature_verify_fn dsa_verify;
  41 static OSSL_FUNC_signature_digest_sign_init_fn dsa_digest_signverify_init;
  42 static OSSL_FUNC_signature_digest_sign_update_fn dsa_digest_signverify_update;
  43 static OSSL_FUNC_signature_digest_sign_final_fn dsa_digest_sign_final;
  44 static OSSL_FUNC_signature_digest_verify_init_fn dsa_digest_signverify_init;
  45 static OSSL_FUNC_signature_digest_verify_update_fn dsa_digest_signverify_update;
  46 static OSSL_FUNC_signature_digest_verify_final_fn dsa_digest_verify_final;
  47 static OSSL_FUNC_signature_freectx_fn dsa_freectx;
  48 static OSSL_FUNC_signature_dupctx_fn dsa_dupctx;
  49 static OSSL_FUNC_signature_get_ctx_params_fn dsa_get_ctx_params;
  50 static OSSL_FUNC_signature_gettable_ctx_params_fn dsa_gettable_ctx_params;
  51 static OSSL_FUNC_signature_set_ctx_params_fn dsa_set_ctx_params;
  52 static OSSL_FUNC_signature_settable_ctx_params_fn dsa_settable_ctx_params;
  53 static OSSL_FUNC_signature_get_ctx_md_params_fn dsa_get_ctx_md_params;
  54 static OSSL_FUNC_signature_gettable_ctx_md_params_fn dsa_gettable_ctx_md_params;
  55 static OSSL_FUNC_signature_set_ctx_md_params_fn dsa_set_ctx_md_params;
  56 static OSSL_FUNC_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     char *propq;
  67     DSA *dsa;
  68
  69     /*
  70      * Flag to determine if the hash function can be changed (1) or not (0)
  71      * Because it's dangerous to change during a DigestSign or DigestVerify
  72      * operation, this flag is cleared by their Init function, and set again
  73      * by their Final function.
  74      */
  75     unsigned int flag_allow_md : 1;
  76
  77     char mdname[OSSL_MAX_NAME_SIZE];
  78
  79     /* The Algorithm Identifier of the combined signature algorithm */
  80     unsigned char aid_buf[OSSL_MAX_ALGORITHM_ID_SIZE];
  81     unsigned char *aid;
  82     size_t  aid_len;
  83
  84     /* main digest */
  85     EVP_MD *md;
  86     EVP_MD_CTX *mdctx;
  87     size_t mdsize;
  88 } PROV_DSA_CTX;
  89
  90 static size_t dsa_get_md_size(const PROV_DSA_CTX *pdsactx)
  91 {
  92     if (pdsactx->md != NULL)
  93         return EVP_MD_size(pdsactx->md);
  94     return 0;
  95 }
  96
  97 static int dsa_get_md_nid(const EVP_MD *md)
  98 {
  99     /*
 100      * Because the DSA library deals with NIDs, we need to translate.
 101      * We do so using EVP_MD_is_a(), and therefore need a name to NID
 102      * map.
 103      */
 104     static const OSSL_ITEM name_to_nid[] = {
 105         { NID_sha1,   OSSL_DIGEST_NAME_SHA1   },
 106         { NID_sha224, OSSL_DIGEST_NAME_SHA2_224 },
 107         { NID_sha256, OSSL_DIGEST_NAME_SHA2_256 },
 108         { NID_sha384, OSSL_DIGEST_NAME_SHA2_384 },
 109         { NID_sha512, OSSL_DIGEST_NAME_SHA2_512 },
 110         { NID_sha3_224, OSSL_DIGEST_NAME_SHA3_224 },
 111         { NID_sha3_256, OSSL_DIGEST_NAME_SHA3_256 },
 112         { NID_sha3_384, OSSL_DIGEST_NAME_SHA3_384 },
 113         { NID_sha3_512, OSSL_DIGEST_NAME_SHA3_512 },
 114     };
 115     size_t i;
 116     int mdnid = NID_undef;
 117
 118     if (md == NULL)
 119         goto end;
 120
 121     for (i = 0; i < OSSL_NELEM(name_to_nid); i++) {
 122         if (EVP_MD_is_a(md, name_to_nid[i].ptr)) {
 123             mdnid = (int)name_to_nid[i].id;
 124             break;
 125         }
 126     }
 127
 128     if (mdnid == NID_undef)
 129         ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_DIGEST);
 130
 131  end:
 132     return mdnid;
 133 }
 134
 135 static void *dsa_newctx(void *provctx, const char *propq)
 136 {
 137     PROV_DSA_CTX *pdsactx = OPENSSL_zalloc(sizeof(PROV_DSA_CTX));
 138
 139     if (pdsactx == NULL)
 140         return NULL;
 141
 142     pdsactx->libctx = PROV_LIBRARY_CONTEXT_OF(provctx);
 143     pdsactx->flag_allow_md = 1;
 144     if (propq != NULL && (pdsactx->propq = OPENSSL_strdup(propq)) == NULL) {
 145         OPENSSL_free(pdsactx);
 146         pdsactx = NULL;
 147         ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
 148     }
 149     return pdsactx;
 150 }
 151
 152 static int dsa_setup_md(PROV_DSA_CTX *ctx,
 153                         const char *mdname, const char *mdprops)
 154 {
 155     if (mdprops == NULL)
 156         mdprops = ctx->propq;
 157
 158     if (mdname != NULL) {
 159         EVP_MD *md = EVP_MD_fetch(ctx->libctx, mdname, mdprops);
 160         int md_nid = dsa_get_md_nid(md);
 161         WPACKET pkt;
 162
 163         if (md == NULL || md_nid == NID_undef) {
 164             EVP_MD_free(md);
 165             return 0;
 166         }
 167
 168         EVP_MD_CTX_free(ctx->mdctx);
 169         EVP_MD_free(ctx->md);
 170
 171         /*
 172          * TODO(3.0) Should we care about DER writing errors?
 173          * All it really means is that for some reason, there's no
 174          * AlgorithmIdentifier to be had, but the operation itself is
 175          * still valid, just as long as it's not used to construct
 176          * anything that needs an AlgorithmIdentifier.
 177          */
 178         ctx->aid_len = 0;
 179         if (WPACKET_init_der(&pkt, ctx->aid_buf, sizeof(ctx->aid_buf))
 180             && DER_w_algorithmIdentifier_DSA_with_MD(&pkt, -1, ctx->dsa,
 181                                                      md_nid)
 182             && WPACKET_finish(&pkt)) {
 183             WPACKET_get_total_written(&pkt, &ctx->aid_len);
 184             ctx->aid = WPACKET_get_curr(&pkt);
 185         }
 186         WPACKET_cleanup(&pkt);
 187
 188         ctx->mdctx = NULL;
 189         ctx->md = md;
 190         OPENSSL_strlcpy(ctx->mdname, mdname, sizeof(ctx->mdname));
 191     }
 192     return 1;
 193 }
 194
 195 static int dsa_signature_init(void *vpdsactx, void *vdsa)
 196 {
 197     PROV_DSA_CTX *pdsactx = (PROV_DSA_CTX *)vpdsactx;
 198
 199     if (pdsactx == NULL || vdsa == NULL || !DSA_up_ref(vdsa))
 200         return 0;
 201     DSA_free(pdsactx->dsa);
 202     pdsactx->dsa = vdsa;
 203     return 1;
 204 }
 205
 206 static int dsa_sign(void *vpdsactx, unsigned char *sig, size_t *siglen,
 207                     size_t sigsize, const unsigned char *tbs, size_t tbslen)
 208 {
 209     PROV_DSA_CTX *pdsactx = (PROV_DSA_CTX *)vpdsactx;
 210     int ret;
 211     unsigned int sltmp;
 212     size_t dsasize = DSA_size(pdsactx->dsa);
 213     size_t mdsize = dsa_get_md_size(pdsactx);
 214
 215     if (sig == NULL) {
 216         *siglen = dsasize;
 217         return 1;
 218     }
 219
 220     if (sigsize < (size_t)dsasize)
 221         return 0;
 222
 223     if (mdsize != 0 && tbslen != mdsize)
 224         return 0;
 225
 226     ret = dsa_sign_int(0, tbs, tbslen, sig, &sltmp, pdsactx->dsa);
 227     if (ret <= 0)
 228         return 0;
 229
 230     *siglen = sltmp;
 231     return 1;
 232 }
 233
 234 static int dsa_verify(void *vpdsactx, const unsigned char *sig, size_t siglen,
 235                       const unsigned char *tbs, size_t tbslen)
 236 {
 237     PROV_DSA_CTX *pdsactx = (PROV_DSA_CTX *)vpdsactx;
 238     size_t mdsize = dsa_get_md_size(pdsactx);
 239
 240     if (mdsize != 0 && tbslen != mdsize)
 241         return 0;
 242
 243     return DSA_verify(0, tbs, tbslen, sig, siglen, pdsactx->dsa);
 244 }
 245
 246 static int dsa_digest_signverify_init(void *vpdsactx, const char *mdname,
 247                                       void *vdsa)
 248 {
 249     PROV_DSA_CTX *pdsactx = (PROV_DSA_CTX *)vpdsactx;
 250
 251     pdsactx->flag_allow_md = 0;
 252     if (!dsa_signature_init(vpdsactx, vdsa))
 253         return 0;
 254
 255     if (!dsa_setup_md(pdsactx, mdname, NULL))
 256         return 0;
 257
 258     pdsactx->mdctx = EVP_MD_CTX_new();
 259     if (pdsactx->mdctx == NULL)
 260         goto error;
 261
 262     if (!EVP_DigestInit_ex(pdsactx->mdctx, pdsactx->md, NULL))
 263         goto error;
 264
 265     return 1;
 266
 267  error:
 268     EVP_MD_CTX_free(pdsactx->mdctx);
 269     EVP_MD_free(pdsactx->md);
 270     pdsactx->mdctx = NULL;
 271     pdsactx->md = NULL;
 272     return 0;
 273 }
 274
 275 int dsa_digest_signverify_update(void *vpdsactx, const unsigned char *data,
 276                                  size_t datalen)
 277 {
 278     PROV_DSA_CTX *pdsactx = (PROV_DSA_CTX *)vpdsactx;
 279
 280     if (pdsactx == NULL || pdsactx->mdctx == NULL)
 281         return 0;
 282
 283     return EVP_DigestUpdate(pdsactx->mdctx, data, datalen);
 284 }
 285
 286 int dsa_digest_sign_final(void *vpdsactx, unsigned char *sig, size_t *siglen,
 287                           size_t sigsize)
 288 {
 289     PROV_DSA_CTX *pdsactx = (PROV_DSA_CTX *)vpdsactx;
 290     unsigned char digest[EVP_MAX_MD_SIZE];
 291     unsigned int dlen = 0;
 292
 293     if (pdsactx == NULL || pdsactx->mdctx == NULL)
 294         return 0;
 295
 296     /*
 297      * If sig is NULL then we're just finding out the sig size. Other fields
 298      * are ignored. Defer to dsa_sign.
 299      */
 300     if (sig != NULL) {
 301         /*
 302          * TODO(3.0): There is the possibility that some externally provided
 303          * digests exceed EVP_MAX_MD_SIZE. We should probably handle that somehow -
 304          * but that problem is much larger than just in DSA.
 305          */
 306         if (!EVP_DigestFinal_ex(pdsactx->mdctx, digest, &dlen))
 307             return 0;
 308     }
 309
 310     pdsactx->flag_allow_md = 1;
 311
 312     return dsa_sign(vpdsactx, sig, siglen, sigsize, digest, (size_t)dlen);
 313 }
 314
 315
 316 int dsa_digest_verify_final(void *vpdsactx, const unsigned char *sig,
 317                             size_t siglen)
 318 {
 319     PROV_DSA_CTX *pdsactx = (PROV_DSA_CTX *)vpdsactx;
 320     unsigned char digest[EVP_MAX_MD_SIZE];
 321     unsigned int dlen = 0;
 322
 323     if (pdsactx == NULL || pdsactx->mdctx == NULL)
 324         return 0;
 325
 326     /*
 327      * TODO(3.0): There is the possibility that some externally provided
 328      * digests exceed EVP_MAX_MD_SIZE. We should probably handle that somehow -
 329      * but that problem is much larger than just in DSA.
 330      */
 331     if (!EVP_DigestFinal_ex(pdsactx->mdctx, digest, &dlen))
 332         return 0;
 333
 334     pdsactx->flag_allow_md = 1;
 335
 336     return dsa_verify(vpdsactx, sig, siglen, digest, (size_t)dlen);
 337 }
 338
 339 static void dsa_freectx(void *vpdsactx)
 340 {
 341     PROV_DSA_CTX *ctx = (PROV_DSA_CTX *)vpdsactx;
 342
 343     OPENSSL_free(ctx->propq);
 344     EVP_MD_CTX_free(ctx->mdctx);
 345     EVP_MD_free(ctx->md);
 346     ctx->propq = NULL;
 347     ctx->mdctx = NULL;
 348     ctx->md = NULL;
 349     ctx->mdsize = 0;
 350     DSA_free(ctx->dsa);
 351     OPENSSL_free(ctx);
 352 }
 353
 354 static void *dsa_dupctx(void *vpdsactx)
 355 {
 356     PROV_DSA_CTX *srcctx = (PROV_DSA_CTX *)vpdsactx;
 357     PROV_DSA_CTX *dstctx;
 358
 359     dstctx = OPENSSL_zalloc(sizeof(*srcctx));
 360     if (dstctx == NULL)
 361         return NULL;
 362
 363     *dstctx = *srcctx;
 364     dstctx->dsa = NULL;
 365     dstctx->md = NULL;
 366     dstctx->mdctx = NULL;
 367
 368     if (srcctx->dsa != NULL && !DSA_up_ref(srcctx->dsa))
 369         goto err;
 370     dstctx->dsa = srcctx->dsa;
 371
 372     if (srcctx->md != NULL && !EVP_MD_up_ref(srcctx->md))
 373         goto err;
 374     dstctx->md = srcctx->md;
 375
 376     if (srcctx->mdctx != NULL) {
 377         dstctx->mdctx = EVP_MD_CTX_new();
 378         if (dstctx->mdctx == NULL
 379                 || !EVP_MD_CTX_copy_ex(dstctx->mdctx, srcctx->mdctx))
 380             goto err;
 381     }
 382
 383     return dstctx;
 384  err:
 385     dsa_freectx(dstctx);
 386     return NULL;
 387 }
 388
 389 static int dsa_get_ctx_params(void *vpdsactx, OSSL_PARAM *params)
 390 {
 391     PROV_DSA_CTX *pdsactx = (PROV_DSA_CTX *)vpdsactx;
 392     OSSL_PARAM *p;
 393
 394     if (pdsactx == NULL || params == NULL)
 395         return 0;
 396
 397     p = OSSL_PARAM_locate(params, OSSL_SIGNATURE_PARAM_ALGORITHM_ID);
 398     if (p != NULL
 399         && !OSSL_PARAM_set_octet_string(p, pdsactx->aid, pdsactx->aid_len))
 400         return 0;
 401
 402     p = OSSL_PARAM_locate(params, OSSL_SIGNATURE_PARAM_DIGEST);
 403     if (p != NULL && !OSSL_PARAM_set_utf8_string(p, pdsactx->mdname))
 404         return 0;
 405
 406     return 1;
 407 }
 408
 409 static const OSSL_PARAM known_gettable_ctx_params[] = {
 410     OSSL_PARAM_octet_string(OSSL_SIGNATURE_PARAM_ALGORITHM_ID, NULL, 0),
 411     OSSL_PARAM_utf8_string(OSSL_SIGNATURE_PARAM_DIGEST, NULL, 0),
 412     OSSL_PARAM_END
 413 };
 414
 415 static const OSSL_PARAM *dsa_gettable_ctx_params(void)
 416 {
 417     return known_gettable_ctx_params;
 418 }
 419
 420 static int dsa_set_ctx_params(void *vpdsactx, const OSSL_PARAM params[])
 421 {
 422     PROV_DSA_CTX *pdsactx = (PROV_DSA_CTX *)vpdsactx;
 423     const OSSL_PARAM *p;
 424
 425     if (pdsactx == NULL || params == NULL)
 426         return 0;
 427
 428     p = OSSL_PARAM_locate_const(params, OSSL_SIGNATURE_PARAM_DIGEST);
 429     /* Not allowed during certain operations */
 430     if (p != NULL && !pdsactx->flag_allow_md)
 431         return 0;
 432     if (p != NULL) {
 433         char mdname[OSSL_MAX_NAME_SIZE] = "", *pmdname = mdname;
 434         char mdprops[OSSL_MAX_PROPQUERY_SIZE] = "", *pmdprops = mdprops;
 435         const OSSL_PARAM *propsp =
 436             OSSL_PARAM_locate_const(params,
 437                                     OSSL_SIGNATURE_PARAM_PROPERTIES);
 438
 439         if (!OSSL_PARAM_get_utf8_string(p, &pmdname, sizeof(mdname)))
 440             return 0;
 441         if (propsp != NULL
 442             && !OSSL_PARAM_get_utf8_string(propsp, &pmdprops, sizeof(mdprops)))
 443             return 0;
 444         if (!dsa_setup_md(pdsactx, mdname, mdprops))
 445             return 0;
 446     }
 447
 448     return 1;
 449 }
 450
 451 static const OSSL_PARAM known_settable_ctx_params[] = {
 452     OSSL_PARAM_utf8_string(OSSL_SIGNATURE_PARAM_DIGEST, NULL, 0),
 453     OSSL_PARAM_utf8_string(OSSL_SIGNATURE_PARAM_PROPERTIES, NULL, 0),
 454     OSSL_PARAM_END
 455 };
 456
 457 static const OSSL_PARAM *dsa_settable_ctx_params(void)
 458 {
 459     /*
 460      * TODO(3.0): Should this function return a different set of settable ctx
 461      * params if the ctx is being used for a DigestSign/DigestVerify? In that
 462      * case it is not allowed to set the digest size/digest name because the
 463      * digest is explicitly set as part of the init.
 464      */
 465     return known_settable_ctx_params;
 466 }
 467
 468 static int dsa_get_ctx_md_params(void *vpdsactx, OSSL_PARAM *params)
 469 {
 470     PROV_DSA_CTX *pdsactx = (PROV_DSA_CTX *)vpdsactx;
 471
 472     if (pdsactx->mdctx == NULL)
 473         return 0;
 474
 475     return EVP_MD_CTX_get_params(pdsactx->mdctx, params);
 476 }
 477
 478 static const OSSL_PARAM *dsa_gettable_ctx_md_params(void *vpdsactx)
 479 {
 480     PROV_DSA_CTX *pdsactx = (PROV_DSA_CTX *)vpdsactx;
 481
 482     if (pdsactx->md == NULL)
 483         return 0;
 484
 485     return EVP_MD_gettable_ctx_params(pdsactx->md);
 486 }
 487
 488 static int dsa_set_ctx_md_params(void *vpdsactx, const OSSL_PARAM params[])
 489 {
 490     PROV_DSA_CTX *pdsactx = (PROV_DSA_CTX *)vpdsactx;
 491
 492     if (pdsactx->mdctx == NULL)
 493         return 0;
 494
 495     return EVP_MD_CTX_set_params(pdsactx->mdctx, params);
 496 }
 497
 498 static const OSSL_PARAM *dsa_settable_ctx_md_params(void *vpdsactx)
 499 {
 500     PROV_DSA_CTX *pdsactx = (PROV_DSA_CTX *)vpdsactx;
 501
 502     if (pdsactx->md == NULL)
 503         return 0;
 504
 505     return EVP_MD_settable_ctx_params(pdsactx->md);
 506 }
 507
 508 const OSSL_DISPATCH dsa_signature_functions[] = {
 509     { OSSL_FUNC_SIGNATURE_NEWCTX, (void (*)(void))dsa_newctx },
 510     { OSSL_FUNC_SIGNATURE_SIGN_INIT, (void (*)(void))dsa_signature_init },
 511     { OSSL_FUNC_SIGNATURE_SIGN, (void (*)(void))dsa_sign },
 512     { OSSL_FUNC_SIGNATURE_VERIFY_INIT, (void (*)(void))dsa_signature_init },
 513     { OSSL_FUNC_SIGNATURE_VERIFY, (void (*)(void))dsa_verify },
 514     { OSSL_FUNC_SIGNATURE_DIGEST_SIGN_INIT,
 515       (void (*)(void))dsa_digest_signverify_init },
 516     { OSSL_FUNC_SIGNATURE_DIGEST_SIGN_UPDATE,
 517       (void (*)(void))dsa_digest_signverify_update },
 518     { OSSL_FUNC_SIGNATURE_DIGEST_SIGN_FINAL,
 519       (void (*)(void))dsa_digest_sign_final },
 520     { OSSL_FUNC_SIGNATURE_DIGEST_VERIFY_INIT,
 521       (void (*)(void))dsa_digest_signverify_init },
 522     { OSSL_FUNC_SIGNATURE_DIGEST_VERIFY_UPDATE,
 523       (void (*)(void))dsa_digest_signverify_update },
 524     { OSSL_FUNC_SIGNATURE_DIGEST_VERIFY_FINAL,
 525       (void (*)(void))dsa_digest_verify_final },
 526     { OSSL_FUNC_SIGNATURE_FREECTX, (void (*)(void))dsa_freectx },
 527     { OSSL_FUNC_SIGNATURE_DUPCTX, (void (*)(void))dsa_dupctx },
 528     { OSSL_FUNC_SIGNATURE_GET_CTX_PARAMS, (void (*)(void))dsa_get_ctx_params },
 529     { OSSL_FUNC_SIGNATURE_GETTABLE_CTX_PARAMS,
 530       (void (*)(void))dsa_gettable_ctx_params },
 531     { OSSL_FUNC_SIGNATURE_SET_CTX_PARAMS, (void (*)(void))dsa_set_ctx_params },
 532     { OSSL_FUNC_SIGNATURE_SETTABLE_CTX_PARAMS,
 533       (void (*)(void))dsa_settable_ctx_params },
 534     { OSSL_FUNC_SIGNATURE_GET_CTX_MD_PARAMS,
 535       (void (*)(void))dsa_get_ctx_md_params },
 536     { OSSL_FUNC_SIGNATURE_GETTABLE_CTX_MD_PARAMS,
 537       (void (*)(void))dsa_gettable_ctx_md_params },
 538     { OSSL_FUNC_SIGNATURE_SET_CTX_MD_PARAMS,
 539       (void (*)(void))dsa_set_ctx_md_params },
 540     { OSSL_FUNC_SIGNATURE_SETTABLE_CTX_MD_PARAMS,
 541       (void (*)(void))dsa_settable_ctx_md_params },
 542     { 0, NULL }
 543 };