providers/implementations/macs/hmac_prov.c

   1 /*
   2  * Copyright 2018-2021 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  * HMAC low level APIs are deprecated for public use, but still ok for internal
  12  * use.
  13  */
  14 #include "internal/deprecated.h"
  15
  16 #include <string.h>
  17
  18 #include <openssl/core_dispatch.h>
  19 #include <openssl/core_names.h>
  20 #include <openssl/params.h>
  21 #include <openssl/engine.h>
  22 #include <openssl/evp.h>
  23 #include <openssl/hmac.h>
  24
  25 #include "prov/implementations.h"
  26 #include "prov/provider_ctx.h"
  27 #include "prov/provider_util.h"
  28 #include "prov/providercommon.h"
  29
  30 /*
  31  * Forward declaration of everything implemented here.  This is not strictly
  32  * necessary for the compiler, but provides an assurance that the signatures
  33  * of the functions in the dispatch table are correct.
  34  */
  35 static OSSL_FUNC_mac_newctx_fn hmac_new;
  36 static OSSL_FUNC_mac_dupctx_fn hmac_dup;
  37 static OSSL_FUNC_mac_freectx_fn hmac_free;
  38 static OSSL_FUNC_mac_gettable_ctx_params_fn hmac_gettable_ctx_params;
  39 static OSSL_FUNC_mac_get_ctx_params_fn hmac_get_ctx_params;
  40 static OSSL_FUNC_mac_settable_ctx_params_fn hmac_settable_ctx_params;
  41 static OSSL_FUNC_mac_set_ctx_params_fn hmac_set_ctx_params;
  42 static OSSL_FUNC_mac_init_fn hmac_init;
  43 static OSSL_FUNC_mac_update_fn hmac_update;
  44 static OSSL_FUNC_mac_final_fn hmac_final;
  45
  46 /* local HMAC context structure */
  47
  48 /* typedef EVP_MAC_IMPL */
  49 struct hmac_data_st {
  50     void *provctx;
  51     HMAC_CTX *ctx;               /* HMAC context */
  52     PROV_DIGEST digest;
  53     unsigned char *key;
  54     size_t keylen;
  55     /* Length of full TLS record including the MAC and any padding */
  56     size_t tls_data_size;
  57     unsigned char tls_header[13];
  58     int tls_header_set;
  59     unsigned char tls_mac_out[EVP_MAX_MD_SIZE];
  60     size_t tls_mac_out_size;
  61 };
  62
  63 /* Defined in ssl/s3_cbc.c */
  64 int ssl3_cbc_digest_record(const EVP_MD *md,
  65                            unsigned char *md_out,
  66                            size_t *md_out_size,
  67                            const unsigned char header[13],
  68                            const unsigned char *data,
  69                            size_t data_size,
  70                            size_t data_plus_mac_plus_padding_size,
  71                            const unsigned char *mac_secret,
  72                            size_t mac_secret_length, char is_sslv3);
  73
  74 static void *hmac_new(void *provctx)
  75 {
  76     struct hmac_data_st *macctx;
  77
  78     if (!ossl_prov_is_running())
  79         return NULL;
  80
  81     if ((macctx = OPENSSL_zalloc(sizeof(*macctx))) == NULL
  82         || (macctx->ctx = HMAC_CTX_new()) == NULL) {
  83         OPENSSL_free(macctx);
  84         return NULL;
  85     }
  86     macctx->provctx = provctx;
  87
  88     return macctx;
  89 }
  90
  91 static void hmac_free(void *vmacctx)
  92 {
  93     struct hmac_data_st *macctx = vmacctx;
  94
  95     if (macctx != NULL) {
  96         HMAC_CTX_free(macctx->ctx);
  97         ossl_prov_digest_reset(&macctx->digest);
  98         OPENSSL_secure_clear_free(macctx->key, macctx->keylen);
  99         OPENSSL_free(macctx);
 100     }
 101 }
 102
 103 static void *hmac_dup(void *vsrc)
 104 {
 105     struct hmac_data_st *src = vsrc;
 106     struct hmac_data_st *dst;
 107     HMAC_CTX *ctx;
 108
 109     if (!ossl_prov_is_running())
 110         return NULL;
 111     dst = hmac_new(src->provctx);
 112     if (dst == NULL)
 113         return NULL;
 114
 115     ctx = dst->ctx;
 116     *dst = *src;
 117     dst->ctx = ctx;
 118     dst->key = NULL;
 119
 120     if (!HMAC_CTX_copy(dst->ctx, src->ctx)
 121         || !ossl_prov_digest_copy(&dst->digest, &src->digest)) {
 122         hmac_free(dst);
 123         return NULL;
 124     }
 125     if (src->key != NULL) {
 126         /* There is no "secure" OPENSSL_memdup */
 127         dst->key = OPENSSL_secure_malloc(src->keylen > 0 ? src->keylen : 1);
 128         if (dst->key == NULL) {
 129             hmac_free(dst);
 130             return 0;
 131         }
 132         memcpy(dst->key, src->key, src->keylen);
 133     }
 134     return dst;
 135 }
 136
 137 static size_t hmac_size(struct hmac_data_st *macctx)
 138 {
 139     return HMAC_size(macctx->ctx);
 140 }
 141
 142 static int hmac_block_size(struct hmac_data_st *macctx)
 143 {
 144     const EVP_MD *md = ossl_prov_digest_md(&macctx->digest);
 145
 146     if (md == NULL)
 147         return 0;
 148     return EVP_MD_block_size(md);
 149 }
 150
 151 static int hmac_setkey(struct hmac_data_st *macctx,
 152                        const unsigned char *key, size_t keylen)
 153 {
 154     const EVP_MD *digest;
 155
 156     if (macctx->keylen > 0)
 157         OPENSSL_secure_clear_free(macctx->key, macctx->keylen);
 158     /* Keep a copy of the key in case we need it for TLS HMAC */
 159     macctx->key = OPENSSL_secure_malloc(keylen > 0 ? keylen : 1);
 160     if (macctx->key == NULL)
 161         return 0;
 162     memcpy(macctx->key, key, keylen);
 163     macctx->keylen = keylen;
 164
 165     digest = ossl_prov_digest_md(&macctx->digest);
 166     /* HMAC_Init_ex doesn't tolerate all zero params, so we must be careful */
 167     if (key != NULL || (macctx->tls_data_size == 0 && digest != NULL))
 168         return HMAC_Init_ex(macctx->ctx, key, keylen, digest,
 169                             ossl_prov_digest_engine(&macctx->digest));
 170     return 1;
 171 }
 172
 173 static int hmac_init(void *vmacctx, const unsigned char *key,
 174                      size_t keylen, const OSSL_PARAM params[])
 175 {
 176     struct hmac_data_st *macctx = vmacctx;
 177
 178     if (!ossl_prov_is_running() || !hmac_set_ctx_params(macctx, params))
 179         return 0;
 180
 181     if (key != NULL && !hmac_setkey(macctx, key, keylen))
 182         return 0;
 183     return 1;
 184 }
 185
 186 static int hmac_update(void *vmacctx, const unsigned char *data,
 187                        size_t datalen)
 188 {
 189     struct hmac_data_st *macctx = vmacctx;
 190
 191     if (macctx->tls_data_size > 0) {
 192         /* We're doing a TLS HMAC */
 193         if (!macctx->tls_header_set) {
 194             /* We expect the first update call to contain the TLS header */
 195             if (datalen != sizeof(macctx->tls_header))
 196                 return 0;
 197             memcpy(macctx->tls_header, data, datalen);
 198             macctx->tls_header_set = 1;
 199             return 1;
 200         }
 201         /* macctx->tls_data_size is datalen plus the padding length */
 202         if (macctx->tls_data_size < datalen)
 203             return 0;
 204
 205         return ssl3_cbc_digest_record(ossl_prov_digest_md(&macctx->digest),
 206                                       macctx->tls_mac_out,
 207                                       &macctx->tls_mac_out_size,
 208                                       macctx->tls_header,
 209                                       data,
 210                                       datalen,
 211                                       macctx->tls_data_size,
 212                                       macctx->key,
 213                                       macctx->keylen,
 214                                       0);
 215     }
 216
 217     return HMAC_Update(macctx->ctx, data, datalen);
 218 }
 219
 220 static int hmac_final(void *vmacctx, unsigned char *out, size_t *outl,
 221                       size_t outsize)
 222 {
 223     unsigned int hlen;
 224     struct hmac_data_st *macctx = vmacctx;
 225
 226     if (!ossl_prov_is_running())
 227         return 0;
 228     if (macctx->tls_data_size > 0) {
 229         if (macctx->tls_mac_out_size == 0)
 230             return 0;
 231         if (outl != NULL)
 232             *outl = macctx->tls_mac_out_size;
 233         memcpy(out, macctx->tls_mac_out, macctx->tls_mac_out_size);
 234         return 1;
 235     }
 236     if (!HMAC_Final(macctx->ctx, out, &hlen))
 237         return 0;
 238     *outl = hlen;
 239     return 1;
 240 }
 241
 242 static const OSSL_PARAM known_gettable_ctx_params[] = {
 243     OSSL_PARAM_size_t(OSSL_MAC_PARAM_SIZE, NULL),
 244     OSSL_PARAM_size_t(OSSL_MAC_PARAM_BLOCK_SIZE, NULL),
 245     OSSL_PARAM_END
 246 };
 247 static const OSSL_PARAM *hmac_gettable_ctx_params(ossl_unused void *ctx,
 248                                                   ossl_unused void *provctx)
 249 {
 250     return known_gettable_ctx_params;
 251 }
 252
 253 static int hmac_get_ctx_params(void *vmacctx, OSSL_PARAM params[])
 254 {
 255     struct hmac_data_st *macctx = vmacctx;
 256     OSSL_PARAM *p;
 257
 258     if ((p = OSSL_PARAM_locate(params, OSSL_MAC_PARAM_SIZE)) != NULL
 259             && !OSSL_PARAM_set_size_t(p, hmac_size(macctx)))
 260         return 0;
 261
 262     if ((p = OSSL_PARAM_locate(params, OSSL_MAC_PARAM_BLOCK_SIZE)) != NULL
 263             && !OSSL_PARAM_set_int(p, hmac_block_size(macctx)))
 264         return 0;
 265
 266     return 1;
 267 }
 268
 269 static const OSSL_PARAM known_settable_ctx_params[] = {
 270     OSSL_PARAM_utf8_string(OSSL_MAC_PARAM_DIGEST, NULL, 0),
 271     OSSL_PARAM_utf8_string(OSSL_MAC_PARAM_PROPERTIES, NULL, 0),
 272     OSSL_PARAM_octet_string(OSSL_MAC_PARAM_KEY, NULL, 0),
 273     OSSL_PARAM_int(OSSL_MAC_PARAM_DIGEST_NOINIT, NULL),
 274     OSSL_PARAM_int(OSSL_MAC_PARAM_DIGEST_ONESHOT, NULL),
 275     OSSL_PARAM_size_t(OSSL_MAC_PARAM_TLS_DATA_SIZE, NULL),
 276     OSSL_PARAM_END
 277 };
 278 static const OSSL_PARAM *hmac_settable_ctx_params(ossl_unused void *ctx,
 279                                                   ossl_unused void *provctx)
 280 {
 281     return known_settable_ctx_params;
 282 }
 283
 284 static int set_flag(const OSSL_PARAM params[], const char *key, int mask,
 285                     int *flags)
 286 {
 287     const OSSL_PARAM *p = OSSL_PARAM_locate_const(params, key);
 288     int flag = 0;
 289
 290     if (p != NULL) {
 291         if (!OSSL_PARAM_get_int(p, &flag))
 292             return 0;
 293         if (flag == 0)
 294             *flags &= ~mask;
 295         else
 296             *flags |= mask;
 297     }
 298     return 1;
 299 }
 300
 301 /*
 302  * ALL parameters should be set before init().
 303  */
 304 static int hmac_set_ctx_params(void *vmacctx, const OSSL_PARAM params[])
 305 {
 306     struct hmac_data_st *macctx = vmacctx;
 307     OSSL_LIB_CTX *ctx = PROV_LIBCTX_OF(macctx->provctx);
 308     const OSSL_PARAM *p;
 309     int flags = 0;
 310
 311     if (params == NULL)
 312         return 1;
 313
 314     if (!ossl_prov_digest_load_from_params(&macctx->digest, params, ctx))
 315         return 0;
 316
 317     if (!set_flag(params, OSSL_MAC_PARAM_DIGEST_NOINIT, EVP_MD_CTX_FLAG_NO_INIT,
 318                   &flags))
 319         return 0;
 320     if (!set_flag(params, OSSL_MAC_PARAM_DIGEST_ONESHOT, EVP_MD_CTX_FLAG_ONESHOT,
 321                   &flags))
 322         return 0;
 323     if (flags)
 324         HMAC_CTX_set_flags(macctx->ctx, flags);
 325
 326     if ((p = OSSL_PARAM_locate_const(params, OSSL_MAC_PARAM_KEY)) != NULL) {
 327         if (p->data_type != OSSL_PARAM_OCTET_STRING)
 328             return 0;
 329
 330         if (macctx->keylen > 0)
 331             OPENSSL_secure_clear_free(macctx->key, macctx->keylen);
 332         /* Keep a copy of the key if we need it for TLS HMAC */
 333         macctx->key = OPENSSL_secure_malloc(p->data_size > 0 ? p->data_size : 1);
 334         if (macctx->key == NULL)
 335             return 0;
 336         memcpy(macctx->key, p->data, p->data_size);
 337         macctx->keylen = p->data_size;
 338
 339         if (!HMAC_Init_ex(macctx->ctx, p->data, p->data_size,
 340                           ossl_prov_digest_md(&macctx->digest),
 341                           NULL /* ENGINE */))
 342             return 0;
 343
 344     }
 345     if ((p = OSSL_PARAM_locate_const(params,
 346                                      OSSL_MAC_PARAM_TLS_DATA_SIZE)) != NULL) {
 347         if (!OSSL_PARAM_get_size_t(p, &macctx->tls_data_size))
 348             return 0;
 349     }
 350     return 1;
 351 }
 352
 353 const OSSL_DISPATCH ossl_hmac_functions[] = {
 354     { OSSL_FUNC_MAC_NEWCTX, (void (*)(void))hmac_new },
 355     { OSSL_FUNC_MAC_DUPCTX, (void (*)(void))hmac_dup },
 356     { OSSL_FUNC_MAC_FREECTX, (void (*)(void))hmac_free },
 357     { OSSL_FUNC_MAC_INIT, (void (*)(void))hmac_init },
 358     { OSSL_FUNC_MAC_UPDATE, (void (*)(void))hmac_update },
 359     { OSSL_FUNC_MAC_FINAL, (void (*)(void))hmac_final },
 360     { OSSL_FUNC_MAC_GETTABLE_CTX_PARAMS,
 361       (void (*)(void))hmac_gettable_ctx_params },
 362     { OSSL_FUNC_MAC_GET_CTX_PARAMS, (void (*)(void))hmac_get_ctx_params },
 363     { OSSL_FUNC_MAC_SETTABLE_CTX_PARAMS,
 364       (void (*)(void))hmac_settable_ctx_params },
 365     { OSSL_FUNC_MAC_SET_CTX_PARAMS, (void (*)(void))hmac_set_ctx_params },
 366     { 0, NULL }
 367 };