crypto/packet.c

   1 /*
   2  * Copyright 2015-2018 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/sslerr.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         SSLerr(SSL_F_WPACKET_INTERN_INIT_LEN, 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, size_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
 229 /*
 230  * Internal helper function used by WPACKET_close(), WPACKET_finish() and
 231  * WPACKET_fill_lengths() to close a sub-packet and write out its length if
 232  * necessary. If |doclose| is 0 then it goes through the motions of closing
 233  * (i.e. it fills in all the lengths), but doesn't actually close anything.
 234  */
 235 static int wpacket_intern_close(WPACKET *pkt, WPACKET_SUB *sub, int doclose)
 236 {
 237     size_t packlen = pkt->written - sub->pwritten;
 238
 239     if (packlen == 0
 240             && (sub->flags & WPACKET_FLAGS_NON_ZERO_LENGTH) != 0)
 241         return 0;
 242
 243     if (packlen == 0
 244             && sub->flags & WPACKET_FLAGS_ABANDON_ON_ZERO_LENGTH) {
 245         /* We can't handle this case. Return an error */
 246         if (!doclose)
 247             return 0;
 248
 249         /* Deallocate any bytes allocated for the length of the WPACKET */
 250         if ((pkt->curr - sub->lenbytes) == sub->packet_len) {
 251             pkt->written -= sub->lenbytes;
 252             pkt->curr -= sub->lenbytes;
 253         }
 254
 255         /* Don't write out the packet length */
 256         sub->packet_len = 0;
 257         sub->lenbytes = 0;
 258     }
 259
 260     /* Write out the WPACKET length if needed */
 261     if (sub->lenbytes > 0) {
 262         unsigned char *buf = GETBUF(pkt);
 263
 264         if (buf != NULL
 265                 && !put_value(&buf[sub->packet_len], packlen,
 266                               sub->lenbytes))
 267             return 0;
 268     } else if (pkt->endfirst && sub->parent != NULL) {
 269         size_t tmplen = packlen;
 270         size_t numlenbytes = 1;
 271
 272         while ((tmplen = tmplen >> 8) > 0)
 273             numlenbytes++;
 274         if (!WPACKET_put_bytes__(pkt, packlen, numlenbytes))
 275             return 0;
 276         if (packlen > 0x7f) {
 277             numlenbytes |= 0x80;
 278             if (!WPACKET_put_bytes_u8(pkt, numlenbytes))
 279                 return 0;
 280         }
 281     }
 282
 283     if (doclose) {
 284         pkt->subs = sub->parent;
 285         OPENSSL_free(sub);
 286     }
 287
 288     return 1;
 289 }
 290
 291 int WPACKET_fill_lengths(WPACKET *pkt)
 292 {
 293     WPACKET_SUB *sub;
 294
 295     if (!ossl_assert(pkt->subs != NULL))
 296         return 0;
 297
 298     for (sub = pkt->subs; sub != NULL; sub = sub->parent) {
 299         if (!wpacket_intern_close(pkt, sub, 0))
 300             return 0;
 301     }
 302
 303     return 1;
 304 }
 305
 306 int WPACKET_close(WPACKET *pkt)
 307 {
 308     /*
 309      * Internal API, so should not fail - but we do negative testing of this
 310      * so no assert (otherwise the tests fail)
 311      */
 312     if (pkt->subs == NULL || pkt->subs->parent == NULL)
 313         return 0;
 314
 315     return wpacket_intern_close(pkt, pkt->subs, 1);
 316 }
 317
 318 int WPACKET_finish(WPACKET *pkt)
 319 {
 320     int ret;
 321
 322     /*
 323      * Internal API, so should not fail - but we do negative testing of this
 324      * so no assert (otherwise the tests fail)
 325      */
 326     if (pkt->subs == NULL || pkt->subs->parent != NULL)
 327         return 0;
 328
 329     ret = wpacket_intern_close(pkt, pkt->subs, 1);
 330     if (ret) {
 331         OPENSSL_free(pkt->subs);
 332         pkt->subs = NULL;
 333     }
 334
 335     return ret;
 336 }
 337
 338 int WPACKET_start_sub_packet_len__(WPACKET *pkt, size_t lenbytes)
 339 {
 340     WPACKET_SUB *sub;
 341     unsigned char *lenchars;
 342
 343     /* Internal API, so should not fail */
 344     if (!ossl_assert(pkt->subs != NULL))
 345         return 0;
 346
 347     /* We don't support lenbytes greater than 0 when doing endfirst writing */
 348     if (lenbytes > 0 && pkt->endfirst)
 349         return 0;
 350
 351     if ((sub = OPENSSL_zalloc(sizeof(*sub))) == NULL) {
 352         SSLerr(SSL_F_WPACKET_START_SUB_PACKET_LEN__, ERR_R_MALLOC_FAILURE);
 353         return 0;
 354     }
 355
 356     sub->parent = pkt->subs;
 357     pkt->subs = sub;
 358     sub->pwritten = pkt->written + lenbytes;
 359     sub->lenbytes = lenbytes;
 360
 361     if (lenbytes == 0) {
 362         sub->packet_len = 0;
 363         return 1;
 364     }
 365
 366     sub->packet_len = pkt->written;
 367
 368     if (!WPACKET_allocate_bytes(pkt, lenbytes, &lenchars))
 369         return 0;
 370
 371     return 1;
 372 }
 373
 374 int WPACKET_start_sub_packet(WPACKET *pkt)
 375 {
 376     return WPACKET_start_sub_packet_len__(pkt, 0);
 377 }
 378
 379 int WPACKET_put_bytes__(WPACKET *pkt, unsigned int val, size_t size)
 380 {
 381     unsigned char *data;
 382
 383     /* Internal API, so should not fail */
 384     if (!ossl_assert(size <= sizeof(unsigned int))
 385             || !WPACKET_allocate_bytes(pkt, size, &data)
 386             || !put_value(data, val, size))
 387         return 0;
 388
 389     return 1;
 390 }
 391
 392 int WPACKET_set_max_size(WPACKET *pkt, size_t maxsize)
 393 {
 394     WPACKET_SUB *sub;
 395     size_t lenbytes;
 396
 397     /* Internal API, so should not fail */
 398     if (!ossl_assert(pkt->subs != NULL))
 399         return 0;
 400
 401     /* Find the WPACKET_SUB for the top level */
 402     for (sub = pkt->subs; sub->parent != NULL; sub = sub->parent)
 403         continue;
 404
 405     lenbytes = sub->lenbytes;
 406     if (lenbytes == 0)
 407         lenbytes = sizeof(pkt->maxsize);
 408
 409     if (maxmaxsize(lenbytes) < maxsize || maxsize < pkt->written)
 410         return 0;
 411
 412     pkt->maxsize = maxsize;
 413
 414     return 1;
 415 }
 416
 417 int WPACKET_memset(WPACKET *pkt, int ch, size_t len)
 418 {
 419     unsigned char *dest;
 420
 421     if (len == 0)
 422         return 1;
 423
 424     if (!WPACKET_allocate_bytes(pkt, len, &dest))
 425         return 0;
 426
 427     if (dest != NULL)
 428         memset(dest, ch, len);
 429
 430     return 1;
 431 }
 432
 433 int WPACKET_memcpy(WPACKET *pkt, const void *src, size_t len)
 434 {
 435     unsigned char *dest;
 436
 437     if (len == 0)
 438         return 1;
 439
 440     if (!WPACKET_allocate_bytes(pkt, len, &dest))
 441         return 0;
 442
 443     if (dest != NULL)
 444         memcpy(dest, src, len);
 445
 446     return 1;
 447 }
 448
 449 int WPACKET_sub_memcpy__(WPACKET *pkt, const void *src, size_t len,
 450                          size_t lenbytes)
 451 {
 452     if (!WPACKET_start_sub_packet_len__(pkt, lenbytes)
 453             || !WPACKET_memcpy(pkt, src, len)
 454             || !WPACKET_close(pkt))
 455         return 0;
 456
 457     return 1;
 458 }
 459
 460 int WPACKET_get_total_written(WPACKET *pkt, size_t *written)
 461 {
 462     /* Internal API, so should not fail */
 463     if (!ossl_assert(written != NULL))
 464         return 0;
 465
 466     *written = pkt->written;
 467
 468     return 1;
 469 }
 470
 471 int WPACKET_get_length(WPACKET *pkt, size_t *len)
 472 {
 473     /* Internal API, so should not fail */
 474     if (!ossl_assert(pkt->subs != NULL && len != NULL))
 475         return 0;
 476
 477     *len = pkt->written - pkt->subs->pwritten;
 478
 479     return 1;
 480 }
 481
 482 unsigned char *WPACKET_get_curr(WPACKET *pkt)
 483 {
 484     unsigned char *buf = GETBUF(pkt);
 485
 486     if (buf == NULL)
 487         return NULL;
 488
 489     if (pkt->endfirst)
 490         return buf + pkt->maxsize - pkt->curr;
 491
 492     return buf + pkt->curr;
 493 }
 494
 495 int WPACKET_is_null_buf(WPACKET *pkt)
 496 {
 497     return pkt->buf == NULL && pkt->staticbuf == NULL;
 498 }
 499
 500 void WPACKET_cleanup(WPACKET *pkt)
 501 {
 502     WPACKET_SUB *sub, *parent;
 503
 504     for (sub = pkt->subs; sub != NULL; sub = parent) {
 505         parent = sub->parent;
 506         OPENSSL_free(sub);
 507     }
 508     pkt->subs = NULL;
 509 }