providers/implementations/macs/hmac_prov.c

   1 /*
   2  * Copyright 2018-2023 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/evp.h>
  22 #include <openssl/hmac.h>
  23
  24 #include "internal/ssl3_cbc.h"
  25
  26 #include "prov/implementations.h"
  27 #include "prov/provider_ctx.h"
  28 #include "prov/provider_util.h"
  29 #include "prov/providercommon.h"
  30
  31 /*
  32  * Forward declaration of everything implemented here.  This is not strictly
  33  * necessary for the compiler, but provides an assurance that the signatures
  34  * of the functions in the dispatch table are correct.
  35  */
  36 static OSSL_FUNC_mac_newctx_fn hmac_new;
  37 static OSSL_FUNC_mac_dupctx_fn hmac_dup;
  38 static OSSL_FUNC_mac_freectx_fn hmac_free;
  39 static OSSL_FUNC_mac_gettable_ctx_params_fn hmac_gettable_ctx_params;
  40 static OSSL_FUNC_mac_get_ctx_params_fn hmac_get_ctx_params;
  41 static OSSL_FUNC_mac_settable_ctx_params_fn hmac_settable_ctx_params;
  42 static OSSL_FUNC_mac_set_ctx_params_fn hmac_set_ctx_params;
  43 static OSSL_FUNC_mac_init_fn hmac_init;
  44 static OSSL_FUNC_mac_update_fn hmac_update;
  45 static OSSL_FUNC_mac_final_fn hmac_final;
  46
  47 /* local HMAC context structure */
  48
  49 /* typedef EVP_MAC_IMPL */
  50 struct hmac_data_st {
  51     void *provctx;
  52     HMAC_CTX *ctx;               /* HMAC context */
  53     PROV_DIGEST digest;
  54     unsigned char *key;
  55     size_t keylen;
  56     /* Length of full TLS record including the MAC and any padding */
  57     size_t tls_data_size;
  58     unsigned char tls_header[13];
  59     int tls_header_set;
  60     unsigned char tls_mac_out[EVP_MAX_MD_SIZE];
  61     size_t tls_mac_out_size;
  62 };
  63
  64 static void *hmac_new(void *provctx)
  65 {
  66     struct hmac_data_st *macctx;
  67
  68     if (!ossl_prov_is_running())
  69         return NULL;
  70
  71     if ((macctx = OPENSSL_zalloc(sizeof(*macctx))) == NULL
  72         || (macctx->ctx = HMAC_CTX_new()) == NULL) {
  73         OPENSSL_free(macctx);
  74         return NULL;
  75     }
  76     macctx->provctx = provctx;
  77
  78     return macctx;
  79 }
  80
  81 static void hmac_free(void *vmacctx)
  82 {
  83     struct hmac_data_st *macctx = vmacctx;
  84
  85     if (macctx != NULL) {
  86         HMAC_CTX_free(macctx->ctx);
  87         ossl_prov_digest_reset(&macctx->digest);
  88         OPENSSL_secure_clear_free(macctx->key, macctx->keylen);
  89         OPENSSL_free(macctx);
  90     }
  91 }
  92
  93 static void *hmac_dup(void *vsrc)
  94 {
  95     struct hmac_data_st *src = vsrc;
  96     struct hmac_data_st *dst;
  97     HMAC_CTX *ctx;
  98
  99     if (!ossl_prov_is_running())
 100         return NULL;
 101     dst = hmac_new(src->provctx);
 102     if (dst == NULL)
 103         return NULL;
 104
 105     ctx = dst->ctx;
 106     *dst = *src;
 107     dst->ctx = ctx;
 108     dst->key = NULL;
 109     memset(&dst->digest, 0, sizeof(dst->digest));
 110
 111     if (!HMAC_CTX_copy(dst->ctx, src->ctx)
 112         || !ossl_prov_digest_copy(&dst->digest, &src->digest)) {
 113         hmac_free(dst);
 114         return NULL;
 115     }
 116     if (src->key != NULL) {
 117         /* There is no "secure" OPENSSL_memdup */
 118         dst->key = OPENSSL_secure_malloc(src->keylen > 0 ? src->keylen : 1);
 119         if (dst->key == NULL) {
 120             hmac_free(dst);
 121             return 0;
 122         }
 123         memcpy(dst->key, src->key, src->keylen);
 124     }
 125     return dst;
 126 }
 127
 128 static size_t hmac_size(struct hmac_data_st *macctx)
 129 {
 130     return HMAC_size(macctx->ctx);
 131 }
 132
 133 static int hmac_block_size(struct hmac_data_st *macctx)
 134 {
 135     const EVP_MD *md = ossl_prov_digest_md(&macctx->digest);
 136
 137     if (md == NULL)
 138         return 0;
 139     return EVP_MD_block_size(md);
 140 }
 141
 142 static int hmac_setkey(struct hmac_data_st *macctx,
 143                        const unsigned char *key, size_t keylen)
 144 {
 145     const EVP_MD *digest;
 146
 147     if (macctx->key != NULL)
 148         OPENSSL_secure_clear_free(macctx->key, macctx->keylen);
 149     /* Keep a copy of the key in case we need it for TLS HMAC */
 150     macctx->key = OPENSSL_secure_malloc(keylen > 0 ? keylen : 1);
 151     if (macctx->key == NULL)
 152         return 0;
 153     memcpy(macctx->key, key, keylen);
 154     macctx->keylen = keylen;
 155
 156     digest = ossl_prov_digest_md(&macctx->digest);
 157     /* HMAC_Init_ex doesn't tolerate all zero params, so we must be careful */
 158     if (key != NULL || (macctx->tls_data_size == 0 && digest != NULL))
 159         return HMAC_Init_ex(macctx->ctx, key, keylen, digest,
 160                             ossl_prov_digest_engine(&macctx->digest));
 161     return 1;
 162 }
 163
 164 static int hmac_init(void *vmacctx, const unsigned char *key,
 165                      size_t keylen, const OSSL_PARAM params[])
 166 {
 167     struct hmac_data_st *macctx = vmacctx;
 168
 169     if (!ossl_prov_is_running() || !hmac_set_ctx_params(macctx, params))
 170         return 0;
 171
 172     if (key != NULL)
 173         return hmac_setkey(macctx, key, keylen);
 174
 175     /* Just reinit the HMAC context */
 176     return HMAC_Init_ex(macctx->ctx, NULL, 0, NULL, NULL);
 177 }
 178
 179 static int hmac_update(void *vmacctx, const unsigned char *data,
 180                        size_t datalen)
 181 {
 182     struct hmac_data_st *macctx = vmacctx;
 183
 184     if (macctx->tls_data_size > 0) {
 185         /* We're doing a TLS HMAC */
 186         if (!macctx->tls_header_set) {
 187             /* We expect the first update call to contain the TLS header */
 188             if (datalen != sizeof(macctx->tls_header))
 189                 return 0;
 190             memcpy(macctx->tls_header, data, datalen);
 191             macctx->tls_header_set = 1;
 192             return 1;
 193         }
 194         /* macctx->tls_data_size is datalen plus the padding length */
 195         if (macctx->tls_data_size < datalen)
 196             return 0;
 197
 198         return ssl3_cbc_digest_record(ossl_prov_digest_md(&macctx->digest),
 199                                       macctx->tls_mac_out,
 200                                       &macctx->tls_mac_out_size,
 201                                       macctx->tls_header,
 202                                       data,
 203                                       datalen,
 204                                       macctx->tls_data_size,
 205                                       macctx->key,
 206                                       macctx->keylen,
 207                                       0);
 208     }
 209
 210     return HMAC_Update(macctx->ctx, data, datalen);
 211 }
 212
 213 static int hmac_final(void *vmacctx, unsigned char *out, size_t *outl,
 214                       size_t outsize)
 215 {
 216     unsigned int hlen;
 217     struct hmac_data_st *macctx = vmacctx;
 218
 219     if (!ossl_prov_is_running())
 220         return 0;
 221     if (macctx->tls_data_size > 0) {
 222         if (macctx->tls_mac_out_size == 0)
 223             return 0;
 224         if (outl != NULL)
 225             *outl = macctx->tls_mac_out_size;
 226         memcpy(out, macctx->tls_mac_out, macctx->tls_mac_out_size);
 227         return 1;
 228     }
 229     if (!HMAC_Final(macctx->ctx, out, &hlen))
 230         return 0;
 231     *outl = hlen;
 232     return 1;
 233 }
 234
 235 static const OSSL_PARAM known_gettable_ctx_params[] = {
 236     OSSL_PARAM_size_t(OSSL_MAC_PARAM_SIZE, NULL),
 237     OSSL_PARAM_size_t(OSSL_MAC_PARAM_BLOCK_SIZE, NULL),
 238     OSSL_PARAM_END
 239 };
 240 static const OSSL_PARAM *hmac_gettable_ctx_params(ossl_unused void *ctx,
 241                                                   ossl_unused void *provctx)
 242 {
 243     return known_gettable_ctx_params;
 244 }
 245
 246 static int hmac_get_ctx_params(void *vmacctx, OSSL_PARAM params[])
 247 {
 248     struct hmac_data_st *macctx = vmacctx;
 249     OSSL_PARAM *p;
 250
 251     if ((p = OSSL_PARAM_locate(params, OSSL_MAC_PARAM_SIZE)) != NULL
 252             && !OSSL_PARAM_set_size_t(p, hmac_size(macctx)))
 253         return 0;
 254
 255     if ((p = OSSL_PARAM_locate(params, OSSL_MAC_PARAM_BLOCK_SIZE)) != NULL
 256             && !OSSL_PARAM_set_int(p, hmac_block_size(macctx)))
 257         return 0;
 258
 259     return 1;
 260 }
 261
 262 static const OSSL_PARAM known_settable_ctx_params[] = {
 263     OSSL_PARAM_utf8_string(OSSL_MAC_PARAM_DIGEST, NULL, 0),
 264     OSSL_PARAM_utf8_string(OSSL_MAC_PARAM_PROPERTIES, NULL, 0),
 265     OSSL_PARAM_octet_string(OSSL_MAC_PARAM_KEY, NULL, 0),
 266     OSSL_PARAM_int(OSSL_MAC_PARAM_DIGEST_NOINIT, NULL),
 267     OSSL_PARAM_int(OSSL_MAC_PARAM_DIGEST_ONESHOT, NULL),
 268     OSSL_PARAM_size_t(OSSL_MAC_PARAM_TLS_DATA_SIZE, NULL),
 269     OSSL_PARAM_END
 270 };
 271 static const OSSL_PARAM *hmac_settable_ctx_params(ossl_unused void *ctx,
 272                                                   ossl_unused void *provctx)
 273 {
 274     return known_settable_ctx_params;
 275 }
 276
 277 static int set_flag(const OSSL_PARAM params[], const char *key, int mask,
 278                     int *flags)
 279 {
 280     const OSSL_PARAM *p = OSSL_PARAM_locate_const(params, key);
 281     int flag = 0;
 282
 283     if (p != NULL) {
 284         if (!OSSL_PARAM_get_int(p, &flag))
 285             return 0;
 286         if (flag == 0)
 287             *flags &= ~mask;
 288         else
 289             *flags |= mask;
 290     }
 291     return 1;
 292 }
 293
 294 /*
 295  * ALL parameters should be set before init().
 296  */
 297 static int hmac_set_ctx_params(void *vmacctx, const OSSL_PARAM params[])
 298 {
 299     struct hmac_data_st *macctx = vmacctx;
 300     OSSL_LIB_CTX *ctx = PROV_LIBCTX_OF(macctx->provctx);
 301     const OSSL_PARAM *p;
 302     int flags = 0;
 303
 304     if (params == NULL)
 305         return 1;
 306
 307     if (!ossl_prov_digest_load_from_params(&macctx->digest, params, ctx))
 308         return 0;
 309
 310     if (!set_flag(params, OSSL_MAC_PARAM_DIGEST_NOINIT, EVP_MD_CTX_FLAG_NO_INIT,
 311                   &flags))
 312         return 0;
 313     if (!set_flag(params, OSSL_MAC_PARAM_DIGEST_ONESHOT, EVP_MD_CTX_FLAG_ONESHOT,
 314                   &flags))
 315         return 0;
 316     if (flags)
 317         HMAC_CTX_set_flags(macctx->ctx, flags);
 318
 319     if ((p = OSSL_PARAM_locate_const(params, OSSL_MAC_PARAM_KEY)) != NULL) {
 320         if (p->data_type != OSSL_PARAM_OCTET_STRING)
 321             return 0;
 322         if (!hmac_setkey(macctx, p->data, p->data_size))
 323             return 0;
 324     }
 325
 326     if ((p = OSSL_PARAM_locate_const(params,
 327                                      OSSL_MAC_PARAM_TLS_DATA_SIZE)) != NULL) {
 328         if (!OSSL_PARAM_get_size_t(p, &macctx->tls_data_size))
 329             return 0;
 330     }
 331     return 1;
 332 }
 333
 334 const OSSL_DISPATCH ossl_hmac_functions[] = {
 335     { OSSL_FUNC_MAC_NEWCTX, (void (*)(void))hmac_new },
 336     { OSSL_FUNC_MAC_DUPCTX, (void (*)(void))hmac_dup },
 337     { OSSL_FUNC_MAC_FREECTX, (void (*)(void))hmac_free },
 338     { OSSL_FUNC_MAC_INIT, (void (*)(void))hmac_init },
 339     { OSSL_FUNC_MAC_UPDATE, (void (*)(void))hmac_update },
 340     { OSSL_FUNC_MAC_FINAL, (void (*)(void))hmac_final },
 341     { OSSL_FUNC_MAC_GETTABLE_CTX_PARAMS,
 342       (void (*)(void))hmac_gettable_ctx_params },
 343     { OSSL_FUNC_MAC_GET_CTX_PARAMS, (void (*)(void))hmac_get_ctx_params },
 344     { OSSL_FUNC_MAC_SETTABLE_CTX_PARAMS,
 345       (void (*)(void))hmac_settable_ctx_params },
 346     { OSSL_FUNC_MAC_SET_CTX_PARAMS, (void (*)(void))hmac_set_ctx_params },
 347     OSSL_DISPATCH_END
 348 };