crypto/packet.c

   1 /*
   2  * Copyright 2015-2021 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 #include "internal/cryptlib.h"
  11 #include "internal/packet.h"
  12 #include <openssl/err.h>
  13
  14 #define DEFAULT_BUF_SIZE    256
  15
  16 int WPACKET_allocate_bytes(WPACKET *pkt, size_t len, unsigned char **allocbytes)
  17 {
  18     if (!WPACKET_reserve_bytes(pkt, len, allocbytes))
  19         return 0;
  20
  21     pkt->written += len;
  22     pkt->curr += len;
  23     return 1;
  24 }
  25
  26 int WPACKET_sub_allocate_bytes__(WPACKET *pkt, size_t len,
  27                                  unsigned char **allocbytes, size_t lenbytes)
  28 {
  29     if (!WPACKET_start_sub_packet_len__(pkt, lenbytes)
  30             || !WPACKET_allocate_bytes(pkt, len, allocbytes)
  31             || !WPACKET_close(pkt))
  32         return 0;
  33
  34     return 1;
  35 }
  36
  37 #define GETBUF(p)   (((p)->staticbuf != NULL) \
  38                      ? (p)->staticbuf \
  39                      : ((p)->buf != NULL \
  40                         ? (unsigned char *)(p)->buf->data \
  41                         : NULL))
  42
  43 int WPACKET_reserve_bytes(WPACKET *pkt, size_t len, unsigned char **allocbytes)
  44 {
  45     /* Internal API, so should not fail */
  46     if (!ossl_assert(pkt->subs != NULL && len != 0))
  47         return 0;
  48
  49     if (pkt->maxsize - pkt->written < len)
  50         return 0;
  51
  52     if (pkt->buf != NULL && (pkt->buf->length - pkt->written < len)) {
  53         size_t newlen;
  54         size_t reflen;
  55
  56         reflen = (len > pkt->buf->length) ? len : pkt->buf->length;
  57
  58         if (reflen > SIZE_MAX / 2) {
  59             newlen = SIZE_MAX;
  60         } else {
  61             newlen = reflen * 2;
  62             if (newlen < DEFAULT_BUF_SIZE)
  63                 newlen = DEFAULT_BUF_SIZE;
  64         }
  65         if (BUF_MEM_grow(pkt->buf, newlen) == 0)
  66             return 0;
  67     }
  68     if (allocbytes != NULL) {
  69         *allocbytes = WPACKET_get_curr(pkt);
  70         if (pkt->endfirst && *allocbytes != NULL)
  71             *allocbytes -= len;
  72     }
  73
  74     return 1;
  75 }
  76
  77 int WPACKET_sub_reserve_bytes__(WPACKET *pkt, size_t len,
  78                                 unsigned char **allocbytes, size_t lenbytes)
  79 {
  80     if (pkt->endfirst && lenbytes > 0)
  81         return 0;
  82
  83     if (!WPACKET_reserve_bytes(pkt, lenbytes + len, allocbytes))
  84         return 0;
  85
  86     if (*allocbytes != NULL)
  87         *allocbytes += lenbytes;
  88
  89     return 1;
  90 }
  91
  92 static size_t maxmaxsize(size_t lenbytes)
  93 {
  94     if (lenbytes >= sizeof(size_t) || lenbytes == 0)
  95         return SIZE_MAX;
  96
  97     return ((size_t)1 << (lenbytes * 8)) - 1 + lenbytes;
  98 }
  99
 100 static int wpacket_intern_init_len(WPACKET *pkt, size_t lenbytes)
 101 {
 102     unsigned char *lenchars;
 103
 104     pkt->curr = 0;
 105     pkt->written = 0;
 106
 107     if ((pkt->subs = OPENSSL_zalloc(sizeof(*pkt->subs))) == NULL) {
 108         ERR_raise(ERR_LIB_CRYPTO, ERR_R_MALLOC_FAILURE);
 109         return 0;
 110     }
 111
 112     if (lenbytes == 0)
 113         return 1;
 114
 115     pkt->subs->pwritten = lenbytes;
 116     pkt->subs->lenbytes = lenbytes;
 117
 118     if (!WPACKET_allocate_bytes(pkt, lenbytes, &lenchars)) {
 119         OPENSSL_free(pkt->subs);
 120         pkt->subs = NULL;
 121         return 0;
 122     }
 123     pkt->subs->packet_len = 0;
 124
 125     return 1;
 126 }
 127
 128 int WPACKET_init_static_len(WPACKET *pkt, unsigned char *buf, size_t len,
 129                             size_t lenbytes)
 130 {
 131     size_t max = maxmaxsize(lenbytes);
 132
 133     /* Internal API, so should not fail */
 134     if (!ossl_assert(buf != NULL && len > 0))
 135         return 0;
 136
 137     pkt->staticbuf = buf;
 138     pkt->buf = NULL;
 139     pkt->maxsize = (max < len) ? max : len;
 140     pkt->endfirst = 0;
 141
 142     return wpacket_intern_init_len(pkt, lenbytes);
 143 }
 144
 145 int WPACKET_init_der(WPACKET *pkt, unsigned char *buf, size_t len)
 146 {
 147     /* Internal API, so should not fail */
 148     if (!ossl_assert(buf != NULL && len > 0))
 149         return 0;
 150
 151     pkt->staticbuf = buf;
 152     pkt->buf = NULL;
 153     pkt->maxsize = len;
 154     pkt->endfirst = 1;
 155
 156     return wpacket_intern_init_len(pkt, 0);
 157 }
 158
 159 int WPACKET_init_len(WPACKET *pkt, BUF_MEM *buf, size_t lenbytes)
 160 {
 161     /* Internal API, so should not fail */
 162     if (!ossl_assert(buf != NULL))
 163         return 0;
 164
 165     pkt->staticbuf = NULL;
 166     pkt->buf = buf;
 167     pkt->maxsize = maxmaxsize(lenbytes);
 168     pkt->endfirst = 0;
 169
 170     return wpacket_intern_init_len(pkt, lenbytes);
 171 }
 172
 173 int WPACKET_init(WPACKET *pkt, BUF_MEM *buf)
 174 {
 175     return WPACKET_init_len(pkt, buf, 0);
 176 }
 177
 178 int WPACKET_init_null(WPACKET *pkt, size_t lenbytes)
 179 {
 180     pkt->staticbuf = NULL;
 181     pkt->buf = NULL;
 182     pkt->maxsize = maxmaxsize(lenbytes);
 183     pkt->endfirst = 0;
 184
 185     return wpacket_intern_init_len(pkt, 0);
 186 }
 187
 188 int WPACKET_init_null_der(WPACKET *pkt)
 189 {
 190     pkt->staticbuf = NULL;
 191     pkt->buf = NULL;
 192     pkt->maxsize = SIZE_MAX;
 193     pkt->endfirst = 1;
 194
 195     return wpacket_intern_init_len(pkt, 0);
 196 }
 197
 198 int WPACKET_set_flags(WPACKET *pkt, unsigned int flags)
 199 {
 200     /* Internal API, so should not fail */
 201     if (!ossl_assert(pkt->subs != NULL))
 202         return 0;
 203
 204     pkt->subs->flags = flags;
 205
 206     return 1;
 207 }
 208
 209 /* Store the |value| of length |len| at location |data| */
 210 static int put_value(unsigned char *data, uint64_t value, size_t len)
 211 {
 212     if (data == NULL)
 213         return 1;
 214
 215     for (data += len - 1; len > 0; len--) {
 216         *data = (unsigned char)(value & 0xff);
 217         data--;
 218         value >>= 8;
 219     }
 220
 221     /* Check whether we could fit the value in the assigned number of bytes */
 222     if (value > 0)
 223         return 0;
 224
 225     return 1;
 226 }
 227
 228 static int put_quic_value(unsigned char *data, size_t value, size_t len)
 229 {
 230     if (data == NULL)
 231         return 1;
 232
 233     /* Value too large for field. */
 234     if (ossl_quic_vlint_encode_len(value) > len)
 235         return 0;
 236
 237     ossl_quic_vlint_encode_n(data, value, len);
 238     return 1;
 239 }
 240
 241 /*
 242  * Internal helper function used by WPACKET_close(), WPACKET_finish() and
 243  * WPACKET_fill_lengths() to close a sub-packet and write out its length if
 244  * necessary. If |doclose| is 0 then it goes through the motions of closing
 245  * (i.e. it fills in all the lengths), but doesn't actually close anything.
 246  */
 247 static int wpacket_intern_close(WPACKET *pkt, WPACKET_SUB *sub, int doclose)
 248 {
 249     size_t packlen = pkt->written - sub->pwritten;
 250
 251     if (packlen == 0
 252             && (sub->flags & WPACKET_FLAGS_NON_ZERO_LENGTH) != 0)
 253         return 0;
 254
 255     if (packlen == 0
 256             && sub->flags & WPACKET_FLAGS_ABANDON_ON_ZERO_LENGTH) {
 257         /* We can't handle this case. Return an error */
 258         if (!doclose)
 259             return 0;
 260
 261         /* Deallocate any bytes allocated for the length of the WPACKET */
 262         if ((pkt->curr - sub->lenbytes) == sub->packet_len) {
 263             pkt->written -= sub->lenbytes;
 264             pkt->curr -= sub->lenbytes;
 265         }
 266
 267         /* Don't write out the packet length */
 268         sub->packet_len = 0;
 269         sub->lenbytes = 0;
 270     }
 271
 272     /* Write out the WPACKET length if needed */
 273     if (sub->lenbytes > 0) {
 274         unsigned char *buf = GETBUF(pkt);
 275
 276         if (buf != NULL) {
 277             if ((sub->flags & WPACKET_FLAGS_QUIC_VLINT) == 0) {
 278                 if (!put_value(&buf[sub->packet_len], packlen, sub->lenbytes))
 279                     return 0;
 280             } else {
 281                 if (!put_quic_value(&buf[sub->packet_len], packlen, sub->lenbytes))
 282                     return 0;
 283             }
 284         }
 285     } else if (pkt->endfirst && sub->parent != NULL
 286                && (packlen != 0
 287                    || (sub->flags
 288                        & WPACKET_FLAGS_ABANDON_ON_ZERO_LENGTH) == 0)) {
 289         size_t tmplen = packlen;
 290         size_t numlenbytes = 1;
 291
 292         while ((tmplen = tmplen >> 8) > 0)
 293             numlenbytes++;
 294         if (!WPACKET_put_bytes__(pkt, packlen, numlenbytes))
 295             return 0;
 296         if (packlen > 0x7f) {
 297             numlenbytes |= 0x80;
 298             if (!WPACKET_put_bytes_u8(pkt, numlenbytes))
 299                 return 0;
 300         }
 301     }
 302
 303     if (doclose) {
 304         pkt->subs = sub->parent;
 305         OPENSSL_free(sub);
 306     }
 307
 308     return 1;
 309 }
 310
 311 int WPACKET_fill_lengths(WPACKET *pkt)
 312 {
 313     WPACKET_SUB *sub;
 314
 315     if (!ossl_assert(pkt->subs != NULL))
 316         return 0;
 317
 318     for (sub = pkt->subs; sub != NULL; sub = sub->parent) {
 319         if (!wpacket_intern_close(pkt, sub, 0))
 320             return 0;
 321     }
 322
 323     return 1;
 324 }
 325
 326 int WPACKET_close(WPACKET *pkt)
 327 {
 328     /*
 329      * Internal API, so should not fail - but we do negative testing of this
 330      * so no assert (otherwise the tests fail)
 331      */
 332     if (pkt->subs == NULL || pkt->subs->parent == NULL)
 333         return 0;
 334
 335     return wpacket_intern_close(pkt, pkt->subs, 1);
 336 }
 337
 338 int WPACKET_finish(WPACKET *pkt)
 339 {
 340     int ret;
 341
 342     /*
 343      * Internal API, so should not fail - but we do negative testing of this
 344      * so no assert (otherwise the tests fail)
 345      */
 346     if (pkt->subs == NULL || pkt->subs->parent != NULL)
 347         return 0;
 348
 349     ret = wpacket_intern_close(pkt, pkt->subs, 1);
 350     if (ret) {
 351         OPENSSL_free(pkt->subs);
 352         pkt->subs = NULL;
 353     }
 354
 355     return ret;
 356 }
 357
 358 int WPACKET_start_sub_packet_len__(WPACKET *pkt, size_t lenbytes)
 359 {
 360     WPACKET_SUB *sub;
 361     unsigned char *lenchars;
 362
 363     /* Internal API, so should not fail */
 364     if (!ossl_assert(pkt->subs != NULL))
 365         return 0;
 366
 367     /* We don't support lenbytes greater than 0 when doing endfirst writing */
 368     if (lenbytes > 0 && pkt->endfirst)
 369         return 0;
 370
 371     if ((sub = OPENSSL_zalloc(sizeof(*sub))) == NULL) {
 372         ERR_raise(ERR_LIB_CRYPTO, ERR_R_MALLOC_FAILURE);
 373         return 0;
 374     }
 375
 376     sub->parent = pkt->subs;
 377     pkt->subs = sub;
 378     sub->pwritten = pkt->written + lenbytes;
 379     sub->lenbytes = lenbytes;
 380
 381     if (lenbytes == 0) {
 382         sub->packet_len = 0;
 383         return 1;
 384     }
 385
 386     sub->packet_len = pkt->written;
 387
 388     if (!WPACKET_allocate_bytes(pkt, lenbytes, &lenchars))
 389         return 0;
 390
 391     return 1;
 392 }
 393
 394 int WPACKET_start_sub_packet(WPACKET *pkt)
 395 {
 396     return WPACKET_start_sub_packet_len__(pkt, 0);
 397 }
 398
 399 int WPACKET_put_bytes__(WPACKET *pkt, uint64_t val, size_t size)
 400 {
 401     unsigned char *data;
 402
 403     /* Internal API, so should not fail */
 404     if (!ossl_assert(size <= sizeof(uint64_t))
 405             || !WPACKET_allocate_bytes(pkt, size, &data)
 406             || !put_value(data, val, size))
 407         return 0;
 408
 409     return 1;
 410 }
 411
 412 int WPACKET_set_max_size(WPACKET *pkt, size_t maxsize)
 413 {
 414     WPACKET_SUB *sub;
 415     size_t lenbytes;
 416
 417     /* Internal API, so should not fail */
 418     if (!ossl_assert(pkt->subs != NULL))
 419         return 0;
 420
 421     /* Find the WPACKET_SUB for the top level */
 422     for (sub = pkt->subs; sub->parent != NULL; sub = sub->parent)
 423         continue;
 424
 425     lenbytes = sub->lenbytes;
 426     if (lenbytes == 0)
 427         lenbytes = sizeof(pkt->maxsize);
 428
 429     if (maxmaxsize(lenbytes) < maxsize || maxsize < pkt->written)
 430         return 0;
 431
 432     pkt->maxsize = maxsize;
 433
 434     return 1;
 435 }
 436
 437 int WPACKET_memset(WPACKET *pkt, int ch, size_t len)
 438 {
 439     unsigned char *dest;
 440
 441     if (len == 0)
 442         return 1;
 443
 444     if (!WPACKET_allocate_bytes(pkt, len, &dest))
 445         return 0;
 446
 447     if (dest != NULL)
 448         memset(dest, ch, len);
 449
 450     return 1;
 451 }
 452
 453 int WPACKET_memcpy(WPACKET *pkt, const void *src, size_t len)
 454 {
 455     unsigned char *dest;
 456
 457     if (len == 0)
 458         return 1;
 459
 460     if (!WPACKET_allocate_bytes(pkt, len, &dest))
 461         return 0;
 462
 463     if (dest != NULL)
 464         memcpy(dest, src, len);
 465
 466     return 1;
 467 }
 468
 469 int WPACKET_sub_memcpy__(WPACKET *pkt, const void *src, size_t len,
 470                          size_t lenbytes)
 471 {
 472     if (!WPACKET_start_sub_packet_len__(pkt, lenbytes)
 473             || !WPACKET_memcpy(pkt, src, len)
 474             || !WPACKET_close(pkt))
 475         return 0;
 476
 477     return 1;
 478 }
 479
 480 int WPACKET_get_total_written(WPACKET *pkt, size_t *written)
 481 {
 482     /* Internal API, so should not fail */
 483     if (!ossl_assert(written != NULL))
 484         return 0;
 485
 486     *written = pkt->written;
 487
 488     return 1;
 489 }
 490
 491 int WPACKET_get_length(WPACKET *pkt, size_t *len)
 492 {
 493     /* Internal API, so should not fail */
 494     if (!ossl_assert(pkt->subs != NULL && len != NULL))
 495         return 0;
 496
 497     *len = pkt->written - pkt->subs->pwritten;
 498
 499     return 1;
 500 }
 501
 502 unsigned char *WPACKET_get_curr(WPACKET *pkt)
 503 {
 504     unsigned char *buf = GETBUF(pkt);
 505
 506     if (buf == NULL)
 507         return NULL;
 508
 509     if (pkt->endfirst)
 510         return buf + pkt->maxsize - pkt->curr;
 511
 512     return buf + pkt->curr;
 513 }
 514
 515 int WPACKET_is_null_buf(WPACKET *pkt)
 516 {
 517     return pkt->buf == NULL && pkt->staticbuf == NULL;
 518 }
 519
 520 void WPACKET_cleanup(WPACKET *pkt)
 521 {
 522     WPACKET_SUB *sub, *parent;
 523
 524     for (sub = pkt->subs; sub != NULL; sub = parent) {
 525         parent = sub->parent;
 526         OPENSSL_free(sub);
 527     }
 528     pkt->subs = NULL;
 529 }
 530
 531 int WPACKET_start_quic_sub_packet_bound(WPACKET *pkt, size_t max_len)
 532 {
 533     size_t enclen = ossl_quic_vlint_encode_len(max_len);
 534
 535     if (enclen == 0)
 536         return 0;
 537
 538     if (WPACKET_start_sub_packet_len__(pkt, enclen) == 0)
 539         return 0;
 540
 541     pkt->subs->flags |= WPACKET_FLAGS_QUIC_VLINT;
 542     return 1;
 543 }
 544
 545 int WPACKET_start_quic_sub_packet(WPACKET *pkt)
 546 {
 547     /*
 548      * Assume no (sub)packet will exceed 4GiB, thus the 8-byte encoding need not
 549      * be used.
 550      */
 551     return WPACKET_start_quic_sub_packet_bound(pkt, OSSL_QUIC_VLINT_4B_MIN);
 552 }
 553
 554 int WPACKET_quic_sub_allocate_bytes(WPACKET *pkt, size_t len, unsigned char **allocbytes)
 555 {
 556     if (!WPACKET_start_quic_sub_packet_bound(pkt, len)
 557             || !WPACKET_allocate_bytes(pkt, len, allocbytes)
 558             || !WPACKET_close(pkt))
 559         return 0;
 560
 561     return 1;
 562 }
 563
 564 /*
 565  * Write a QUIC variable-length integer to the packet.
 566  */
 567 int WPACKET_quic_write_vlint(WPACKET *pkt, uint64_t v)
 568 {
 569     unsigned char *b = NULL;
 570     size_t enclen = ossl_quic_vlint_encode_len(v);
 571
 572     if (enclen == 0)
 573         return 0;
 574
 575     if (WPACKET_allocate_bytes(pkt, enclen, &b) == 0)
 576         return 0;
 577
 578     ossl_quic_vlint_encode(b, v);
 579     return 1;
 580 }