providers/common/ciphers/cipher_gcm.c

   1 /*
   2  * Copyright 2019 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 /* Dispatch functions for gcm mode */
  11
  12 #include "cipher_local.h"
  13 #include "internal/ciphers/cipher_gcm.h"
  14 #include "internal/providercommonerr.h"
  15 #include "crypto/rand.h"
  16 #include "internal/provider_ctx.h"
  17
  18 static int gcm_tls_init(PROV_GCM_CTX *dat, unsigned char *aad, size_t aad_len);
  19 static int gcm_tls_iv_set_fixed(PROV_GCM_CTX *ctx, unsigned char *iv,
  20                                 size_t len);
  21 static int gcm_tls_cipher(PROV_GCM_CTX *ctx, unsigned char *out, size_t *padlen,
  22                           const unsigned char *in, size_t len);
  23 static int gcm_cipher_internal(PROV_GCM_CTX *ctx, unsigned char *out,
  24                                size_t *padlen, const unsigned char *in,
  25                                size_t len);
  26
  27 void gcm_initctx(void *provctx, PROV_GCM_CTX *ctx, size_t keybits,
  28                  const PROV_GCM_HW *hw, size_t ivlen_min)
  29 {
  30     ctx->pad = 1;
  31     ctx->mode = EVP_CIPH_GCM_MODE;
  32     ctx->taglen = UNINITIALISED_SIZET;
  33     ctx->tls_aad_len = UNINITIALISED_SIZET;
  34     ctx->ivlen_min = ivlen_min;
  35     ctx->ivlen = (EVP_GCM_TLS_FIXED_IV_LEN + EVP_GCM_TLS_EXPLICIT_IV_LEN);
  36     ctx->keylen = keybits / 8;
  37     ctx->hw = hw;
  38     ctx->libctx = PROV_LIBRARY_CONTEXT_OF(provctx);
  39 }
  40
  41 void gcm_deinitctx(PROV_GCM_CTX *ctx)
  42 {
  43     OPENSSL_cleanse(ctx->iv, sizeof(ctx->iv));
  44 }
  45
  46 static int gcm_init(void *vctx, const unsigned char *key, size_t keylen,
  47                     const unsigned char *iv, size_t ivlen, int enc)
  48 {
  49     PROV_GCM_CTX *ctx = (PROV_GCM_CTX *)vctx;
  50
  51     ctx->enc = enc;
  52
  53     if (iv != NULL) {
  54         if (ivlen < ctx->ivlen_min || ivlen > sizeof(ctx->iv)) {
  55             ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_IV_LENGTH);
  56             return 0;
  57         }
  58         ctx->ivlen = ivlen;
  59         memcpy(ctx->iv, iv, ctx->ivlen);
  60         ctx->iv_state = IV_STATE_BUFFERED;
  61     }
  62
  63     if (key != NULL) {
  64         if (keylen != ctx->keylen) {
  65             ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_KEY_LENGTH);
  66             return 0;
  67         }
  68         return ctx->hw->setkey(ctx, key, ctx->keylen);
  69     }
  70     return 1;
  71 }
  72
  73 int gcm_einit(void *vctx, const unsigned char *key, size_t keylen,
  74               const unsigned char *iv, size_t ivlen)
  75 {
  76     return gcm_init(vctx, key, keylen, iv, ivlen, 1);
  77 }
  78
  79 int gcm_dinit(void *vctx, const unsigned char *key, size_t keylen,
  80               const unsigned char *iv, size_t ivlen)
  81 {
  82     return gcm_init(vctx, key, keylen, iv, ivlen, 0);
  83 }
  84
  85 int gcm_get_ctx_params(void *vctx, OSSL_PARAM params[])
  86 {
  87     PROV_GCM_CTX *ctx = (PROV_GCM_CTX *)vctx;
  88     OSSL_PARAM *p;
  89     size_t sz;
  90
  91     p = OSSL_PARAM_locate(params, OSSL_CIPHER_PARAM_IVLEN);
  92     if (p != NULL && !OSSL_PARAM_set_size_t(p, ctx->ivlen)) {
  93         ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER);
  94         return 0;
  95     }
  96     p = OSSL_PARAM_locate(params, OSSL_CIPHER_PARAM_KEYLEN);
  97     if (p != NULL && !OSSL_PARAM_set_size_t(p, ctx->keylen)) {
  98         ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER);
  99         return 0;
 100     }
 101     p = OSSL_PARAM_locate(params, OSSL_CIPHER_PARAM_AEAD_TAGLEN);
 102     if (p != NULL) {
 103         size_t taglen = (ctx->taglen != UNINITIALISED_SIZET) ? ctx->taglen :
 104                          GCM_TAG_MAX_SIZE;
 105
 106         if (!OSSL_PARAM_set_size_t(p, taglen)) {
 107             ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER);
 108             return 0;
 109         }
 110     }
 111
 112     p = OSSL_PARAM_locate(params, OSSL_CIPHER_PARAM_IV);
 113     if (p != NULL) {
 114         if (ctx->iv_gen != 1 && ctx->iv_gen_rand != 1)
 115             return 0;
 116         if (ctx->ivlen != p->data_size) {
 117             ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_IV_LENGTH);
 118             return 0;
 119         }
 120         if (!OSSL_PARAM_set_octet_string(p, ctx->iv, ctx->ivlen)) {
 121             ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER);
 122             return 0;
 123         }
 124     }
 125
 126     p = OSSL_PARAM_locate(params, OSSL_CIPHER_PARAM_AEAD_TLS1_AAD_PAD);
 127     if (p != NULL && !OSSL_PARAM_set_size_t(p, ctx->tls_aad_pad_sz)) {
 128         ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER);
 129         return 0;
 130     }
 131     p = OSSL_PARAM_locate(params, OSSL_CIPHER_PARAM_AEAD_TAG);
 132     if (p != NULL) {
 133         sz = p->data_size;
 134         if (sz == 0
 135             || sz > EVP_GCM_TLS_TAG_LEN
 136             || !ctx->enc
 137             || ctx->taglen == UNINITIALISED_SIZET) {
 138             ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_TAG);
 139             return 0;
 140         }
 141         if (!OSSL_PARAM_set_octet_string(p, ctx->buf, sz)) {
 142             ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER);
 143             return 0;
 144         }
 145     }
 146
 147     return 1;
 148 }
 149
 150 int gcm_set_ctx_params(void *vctx, const OSSL_PARAM params[])
 151 {
 152     PROV_GCM_CTX *ctx = (PROV_GCM_CTX *)vctx;
 153     const OSSL_PARAM *p;
 154     size_t sz;
 155     void *vp;
 156
 157     p = OSSL_PARAM_locate_const(params, OSSL_CIPHER_PARAM_AEAD_TAG);
 158     if (p != NULL) {
 159         vp = ctx->buf;
 160         if (!OSSL_PARAM_get_octet_string(p, &vp, EVP_GCM_TLS_TAG_LEN, &sz)) {
 161             ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_GET_PARAMETER);
 162             return 0;
 163         }
 164         if (sz == 0 || ctx->enc) {
 165             ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_TAG);
 166             return 0;
 167         }
 168         ctx->taglen = sz;
 169     }
 170
 171     p = OSSL_PARAM_locate_const(params, OSSL_CIPHER_PARAM_AEAD_IVLEN);
 172     if (p != NULL) {
 173         if (!OSSL_PARAM_get_size_t(p, &sz)) {
 174             ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_GET_PARAMETER);
 175             return 0;
 176         }
 177         if (sz == 0 || sz > sizeof(ctx->iv)) {
 178             ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_IV_LENGTH);
 179             return 0;
 180         }
 181         ctx->ivlen = sz;
 182     }
 183
 184     p = OSSL_PARAM_locate_const(params, OSSL_CIPHER_PARAM_AEAD_TLS1_AAD);
 185     if (p != NULL) {
 186         if (p->data_type != OSSL_PARAM_OCTET_STRING) {
 187             ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_GET_PARAMETER);
 188             return 0;
 189         }
 190         sz = gcm_tls_init(ctx, p->data, p->data_size);
 191         if (sz == 0) {
 192             ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_AAD);
 193             return 0;
 194         }
 195         ctx->tls_aad_pad_sz = sz;
 196     }
 197
 198     p = OSSL_PARAM_locate_const(params, OSSL_CIPHER_PARAM_AEAD_TLS1_IV_FIXED);
 199     if (p != NULL) {
 200         if (p->data_type != OSSL_PARAM_OCTET_STRING) {
 201             ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_GET_PARAMETER);
 202             return 0;
 203         }
 204         if (gcm_tls_iv_set_fixed(ctx, p->data, p->data_size) == 0) {
 205             ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_GET_PARAMETER);
 206             return 0;
 207         }
 208     }
 209
 210     /*
 211      * TODO(3.0) Temporary solution to address fuzz test crash, which will be
 212      * reworked once the discussion in PR #9510 is resolved. i.e- We need a
 213      * general solution for handling missing parameters inside set_params and
 214      * get_params methods.
 215      */
 216     p = OSSL_PARAM_locate_const(params, OSSL_CIPHER_PARAM_KEYLEN);
 217     if (p != NULL) {
 218         size_t keylen;
 219
 220         if (!OSSL_PARAM_get_size_t(p, &keylen)) {
 221             ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_GET_PARAMETER);
 222             return 0;
 223         }
 224         /* The key length can not be modified for gcm mode */
 225         if (keylen != ctx->keylen)
 226             return 0;
 227     }
 228
 229     return 1;
 230 }
 231
 232 int gcm_stream_update(void *vctx, unsigned char *out, size_t *outl,
 233                       size_t outsize, const unsigned char *in, size_t inl)
 234 {
 235     PROV_GCM_CTX *ctx = (PROV_GCM_CTX *)vctx;
 236
 237     if (outsize < inl) {
 238         ERR_raise(ERR_LIB_PROV, PROV_R_OUTPUT_BUFFER_TOO_SMALL);
 239         return -1;
 240     }
 241
 242     if (gcm_cipher_internal(ctx, out, outl, in, inl) <= 0) {
 243         ERR_raise(ERR_LIB_PROV, PROV_R_CIPHER_OPERATION_FAILED);
 244         return -1;
 245     }
 246     return 1;
 247 }
 248
 249 int gcm_stream_final(void *vctx, unsigned char *out, size_t *outl,
 250                      size_t outsize)
 251 {
 252     PROV_GCM_CTX *ctx = (PROV_GCM_CTX *)vctx;
 253     int i;
 254
 255     i = gcm_cipher_internal(ctx, out, outl, NULL, 0);
 256     if (i <= 0)
 257         return 0;
 258
 259     *outl = 0;
 260     return 1;
 261 }
 262
 263 int gcm_cipher(void *vctx,
 264                unsigned char *out, size_t *outl, size_t outsize,
 265                const unsigned char *in, size_t inl)
 266 {
 267     PROV_GCM_CTX *ctx = (PROV_GCM_CTX *)vctx;
 268
 269     if (outsize < inl) {
 270         ERR_raise(ERR_LIB_PROV, PROV_R_OUTPUT_BUFFER_TOO_SMALL);
 271         return -1;
 272     }
 273
 274     if (gcm_cipher_internal(ctx, out, outl, in, inl) <= 0)
 275         return -1;
 276
 277     *outl = inl;
 278     return 1;
 279 }
 280
 281 /*
 282  * See SP800-38D (GCM) Section 8 "Uniqueness requirement on IVS and keys"
 283  *
 284  * See also 8.2.2 RBG-based construction.
 285  * Random construction consists of a free field (which can be NULL) and a
 286  * random field which will use a DRBG that can return at least 96 bits of
 287  * entropy strength. (The DRBG must be seeded by the FIPS module).
 288  */
 289 static int gcm_iv_generate(PROV_GCM_CTX *ctx, int offset)
 290 {
 291     int sz = ctx->ivlen - offset;
 292
 293     /* Must be at least 96 bits */
 294     if (sz <= 0 || ctx->ivlen < GCM_IV_DEFAULT_SIZE)
 295         return 0;
 296
 297     /* Use DRBG to generate random iv */
 298     if (rand_bytes_ex(ctx->libctx, ctx->iv + offset, sz) <= 0)
 299         return 0;
 300     ctx->iv_state = IV_STATE_BUFFERED;
 301     ctx->iv_gen_rand = 1;
 302     return 1;
 303 }
 304
 305 static int gcm_cipher_internal(PROV_GCM_CTX *ctx, unsigned char *out,
 306                                size_t *padlen, const unsigned char *in,
 307                                size_t len)
 308 {
 309     size_t olen = 0;
 310     int rv = 0;
 311     const PROV_GCM_HW *hw = ctx->hw;
 312
 313     if (ctx->tls_aad_len != UNINITIALISED_SIZET)
 314         return gcm_tls_cipher(ctx, out, padlen, in, len);
 315
 316     if (!ctx->key_set || ctx->iv_state == IV_STATE_FINISHED)
 317         goto err;
 318
 319     /*
 320      * FIPS requires generation of AES-GCM IV's inside the FIPS module.
 321      * The IV can still be set externally (the security policy will state that
 322      * this is not FIPS compliant). There are some applications
 323      * where setting the IV externally is the only option available.
 324      */
 325     if (ctx->iv_state == IV_STATE_UNINITIALISED) {
 326         if (!ctx->enc || !gcm_iv_generate(ctx, 0))
 327             goto err;
 328     }
 329
 330     if (ctx->iv_state == IV_STATE_BUFFERED) {
 331         if (!hw->setiv(ctx, ctx->iv, ctx->ivlen))
 332             goto err;
 333         ctx->iv_state = IV_STATE_COPIED;
 334     }
 335
 336     if (in != NULL) {
 337         /*  The input is AAD if out is NULL */
 338         if (out == NULL) {
 339             if (!hw->aadupdate(ctx, in, len))
 340                 goto err;
 341         } else {
 342             /* The input is ciphertext OR plaintext */
 343             if (!hw->cipherupdate(ctx, in, len, out))
 344                 goto err;
 345         }
 346     } else {
 347         /* The tag must be set before actually decrypting data */
 348         if (!ctx->enc && ctx->taglen == UNINITIALISED_SIZET)
 349             goto err;
 350         if (!hw->cipherfinal(ctx, ctx->buf))
 351             goto err;
 352         ctx->iv_state = IV_STATE_FINISHED; /* Don't reuse the IV */
 353         goto finish;
 354     }
 355     olen = len;
 356 finish:
 357     rv = 1;
 358 err:
 359     *padlen = olen;
 360     return rv;
 361 }
 362
 363 static int gcm_tls_init(PROV_GCM_CTX *dat, unsigned char *aad, size_t aad_len)
 364 {
 365     unsigned char *buf;
 366     size_t len;
 367
 368     if (aad_len != EVP_AEAD_TLS1_AAD_LEN)
 369        return 0;
 370
 371     /* Save the aad for later use. */
 372     buf = dat->buf;
 373     memcpy(buf, aad, aad_len);
 374     dat->tls_aad_len = aad_len;
 375     dat->tls_enc_records = 0;
 376
 377     len = buf[aad_len - 2] << 8 | buf[aad_len - 1];
 378     /* Correct length for explicit iv. */
 379     if (len < EVP_GCM_TLS_EXPLICIT_IV_LEN)
 380         return 0;
 381     len -= EVP_GCM_TLS_EXPLICIT_IV_LEN;
 382
 383     /* If decrypting correct for tag too. */
 384     if (!dat->enc) {
 385         if (len < EVP_GCM_TLS_TAG_LEN)
 386             return 0;
 387         len -= EVP_GCM_TLS_TAG_LEN;
 388     }
 389     buf[aad_len - 2] = (unsigned char)(len >> 8);
 390     buf[aad_len - 1] = (unsigned char)(len & 0xff);
 391     /* Extra padding: tag appended to record. */
 392     return EVP_GCM_TLS_TAG_LEN;
 393 }
 394
 395 static int gcm_tls_iv_set_fixed(PROV_GCM_CTX *ctx, unsigned char *iv,
 396                                 size_t len)
 397 {
 398     /* Special case: -1 length restores whole IV */
 399     if (len == (size_t)-1) {
 400         memcpy(ctx->iv, iv, ctx->ivlen);
 401         ctx->iv_gen = 1;
 402         ctx->iv_state = IV_STATE_BUFFERED;
 403         return 1;
 404     }
 405     /* Fixed field must be at least 4 bytes and invocation field at least 8 */
 406     if ((len < EVP_GCM_TLS_FIXED_IV_LEN)
 407         || (ctx->ivlen - (int)len) < EVP_GCM_TLS_EXPLICIT_IV_LEN)
 408             return 0;
 409     if (len > 0)
 410         memcpy(ctx->iv, iv, len);
 411     if (ctx->enc
 412         && rand_bytes_ex(ctx->libctx, ctx->iv + len, ctx->ivlen - len) <= 0)
 413             return 0;
 414     ctx->iv_gen = 1;
 415     ctx->iv_state = IV_STATE_BUFFERED;
 416     return 1;
 417 }
 418
 419 /* increment counter (64-bit int) by 1 */
 420 static void ctr64_inc(unsigned char *counter)
 421 {
 422     int n = 8;
 423     unsigned char c;
 424
 425     do {
 426         --n;
 427         c = counter[n];
 428         ++c;
 429         counter[n] = c;
 430         if (c > 0)
 431             return;
 432     } while (n > 0);
 433 }
 434
 435 /*
 436  * Handle TLS GCM packet format. This consists of the last portion of the IV
 437  * followed by the payload and finally the tag. On encrypt generate IV,
 438  * encrypt payload and write the tag. On verify retrieve IV, decrypt payload
 439  * and verify tag.
 440  */
 441 static int gcm_tls_cipher(PROV_GCM_CTX *ctx, unsigned char *out, size_t *padlen,
 442                           const unsigned char *in, size_t len)
 443 {
 444     int rv = 0;
 445     size_t arg = EVP_GCM_TLS_EXPLICIT_IV_LEN;
 446     size_t plen = 0;
 447     unsigned char *tag = NULL;
 448
 449     if (!ctx->key_set)
 450         goto err;
 451
 452     /* Encrypt/decrypt must be performed in place */
 453     if (out != in || len < (EVP_GCM_TLS_EXPLICIT_IV_LEN + EVP_GCM_TLS_TAG_LEN))
 454         goto err;
 455
 456     /*
 457      * Check for too many keys as per FIPS 140-2 IG A.5 "Key/IV Pair Uniqueness
 458      * Requirements from SP 800-38D".  The requirements is for one party to the
 459      * communication to fail after 2^64 - 1 keys.  We do this on the encrypting
 460      * side only.
 461      */
 462     if (ctx->enc && ++ctx->tls_enc_records == 0) {
 463         ERR_raise(ERR_LIB_PROV, EVP_R_TOO_MANY_RECORDS);
 464         goto err;
 465     }
 466
 467     if (ctx->iv_gen == 0)
 468         goto err;
 469     /*
 470      * Set IV from start of buffer or generate IV and write to start of
 471      * buffer.
 472      */
 473     if (ctx->enc) {
 474         if (!ctx->hw->setiv(ctx, ctx->iv, ctx->ivlen))
 475             goto err;
 476         if (arg > ctx->ivlen)
 477             arg = ctx->ivlen;
 478         memcpy(out, ctx->iv + ctx->ivlen - arg, arg);
 479         /*
 480          * Invocation field will be at least 8 bytes in size and so no need
 481          * to check wrap around or increment more than last 8 bytes.
 482          */
 483         ctr64_inc(ctx->iv + ctx->ivlen - 8);
 484     } else {
 485         memcpy(ctx->iv + ctx->ivlen - arg, out, arg);
 486         if (!ctx->hw->setiv(ctx, ctx->iv, ctx->ivlen))
 487             goto err;
 488     }
 489     ctx->iv_state = IV_STATE_COPIED;
 490
 491     /* Fix buffer and length to point to payload */
 492     in += EVP_GCM_TLS_EXPLICIT_IV_LEN;
 493     out += EVP_GCM_TLS_EXPLICIT_IV_LEN;
 494     len -= EVP_GCM_TLS_EXPLICIT_IV_LEN + EVP_GCM_TLS_TAG_LEN;
 495
 496     tag = ctx->enc ? out + len : (unsigned char *)in + len;
 497     if (!ctx->hw->oneshot(ctx, ctx->buf, ctx->tls_aad_len, in, len, out, tag,
 498                           EVP_GCM_TLS_TAG_LEN)) {
 499         if (!ctx->enc)
 500             OPENSSL_cleanse(out, len);
 501         goto err;
 502     }
 503     if (ctx->enc)
 504         plen =  len + EVP_GCM_TLS_EXPLICIT_IV_LEN + EVP_GCM_TLS_TAG_LEN;
 505     else
 506         plen = len;
 507
 508     rv = 1;
 509 err:
 510     ctx->iv_state = IV_STATE_FINISHED;
 511     ctx->tls_aad_len = UNINITIALISED_SIZET;
 512     *padlen = plen;
 513     return rv;
 514 }