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
  71     return 1;
  72 }
  73
  74 int WPACKET_sub_reserve_bytes__(WPACKET *pkt, size_t len,
  75                                 unsigned char **allocbytes, size_t lenbytes)
  76 {
  77     if (!WPACKET_reserve_bytes(pkt, lenbytes + len, allocbytes))
  78         return 0;
  79
  80     if (*allocbytes != NULL)
  81         *allocbytes += lenbytes;
  82
  83     return 1;
  84 }
  85
  86 static size_t maxmaxsize(size_t lenbytes)
  87 {
  88     if (lenbytes >= sizeof(size_t) || lenbytes == 0)
  89         return SIZE_MAX;
  90
  91     return ((size_t)1 << (lenbytes * 8)) - 1 + lenbytes;
  92 }
  93
  94 static int wpacket_intern_init_len(WPACKET *pkt, size_t lenbytes)
  95 {
  96     unsigned char *lenchars;
  97
  98     pkt->curr = 0;
  99     pkt->written = 0;
 100
 101     if ((pkt->subs = OPENSSL_zalloc(sizeof(*pkt->subs))) == NULL) {
 102         SSLerr(SSL_F_WPACKET_INTERN_INIT_LEN, ERR_R_MALLOC_FAILURE);
 103         return 0;
 104     }
 105
 106     if (lenbytes == 0)
 107         return 1;
 108
 109     pkt->subs->pwritten = lenbytes;
 110     pkt->subs->lenbytes = lenbytes;
 111
 112     if (!WPACKET_allocate_bytes(pkt, lenbytes, &lenchars)) {
 113         OPENSSL_free(pkt->subs);
 114         pkt->subs = NULL;
 115         return 0;
 116     }
 117     pkt->subs->packet_len = 0;
 118
 119     return 1;
 120 }
 121
 122 int WPACKET_init_static_len(WPACKET *pkt, unsigned char *buf, size_t len,
 123                             size_t lenbytes)
 124 {
 125     size_t max = maxmaxsize(lenbytes);
 126
 127     /* Internal API, so should not fail */
 128     if (!ossl_assert(buf != NULL && len > 0))
 129         return 0;
 130
 131     pkt->staticbuf = buf;
 132     pkt->buf = NULL;
 133     pkt->maxsize = (max < len) ? max : len;
 134
 135     return wpacket_intern_init_len(pkt, lenbytes);
 136 }
 137
 138 int WPACKET_init_len(WPACKET *pkt, BUF_MEM *buf, size_t lenbytes)
 139 {
 140     /* Internal API, so should not fail */
 141     if (!ossl_assert(buf != NULL))
 142         return 0;
 143
 144     pkt->staticbuf = NULL;
 145     pkt->buf = buf;
 146     pkt->maxsize = maxmaxsize(lenbytes);
 147
 148     return wpacket_intern_init_len(pkt, lenbytes);
 149 }
 150
 151 int WPACKET_init(WPACKET *pkt, BUF_MEM *buf)
 152 {
 153     return WPACKET_init_len(pkt, buf, 0);
 154 }
 155
 156 int WPACKET_init_null(WPACKET *pkt, size_t lenbytes)
 157 {
 158     pkt->staticbuf = NULL;
 159     pkt->buf = NULL;
 160     pkt->maxsize = maxmaxsize(lenbytes);
 161
 162     return wpacket_intern_init_len(pkt, 0);
 163 }
 164
 165 int WPACKET_set_flags(WPACKET *pkt, unsigned int flags)
 166 {
 167     /* Internal API, so should not fail */
 168     if (!ossl_assert(pkt->subs != NULL))
 169         return 0;
 170
 171     pkt->subs->flags = flags;
 172
 173     return 1;
 174 }
 175
 176 /* Store the |value| of length |len| at location |data| */
 177 static int put_value(unsigned char *data, size_t value, size_t len)
 178 {
 179     if (data == NULL)
 180         return 1;
 181
 182     for (data += len - 1; len > 0; len--) {
 183         *data = (unsigned char)(value & 0xff);
 184         data--;
 185         value >>= 8;
 186     }
 187
 188     /* Check whether we could fit the value in the assigned number of bytes */
 189     if (value > 0)
 190         return 0;
 191
 192     return 1;
 193 }
 194
 195
 196 /*
 197  * Internal helper function used by WPACKET_close(), WPACKET_finish() and
 198  * WPACKET_fill_lengths() to close a sub-packet and write out its length if
 199  * necessary. If |doclose| is 0 then it goes through the motions of closing
 200  * (i.e. it fills in all the lengths), but doesn't actually close anything.
 201  */
 202 static int wpacket_intern_close(WPACKET *pkt, WPACKET_SUB *sub, int doclose)
 203 {
 204     size_t packlen = pkt->written - sub->pwritten;
 205
 206     if (packlen == 0
 207             && (sub->flags & WPACKET_FLAGS_NON_ZERO_LENGTH) != 0)
 208         return 0;
 209
 210     if (packlen == 0
 211             && sub->flags & WPACKET_FLAGS_ABANDON_ON_ZERO_LENGTH) {
 212         /* We can't handle this case. Return an error */
 213         if (!doclose)
 214             return 0;
 215
 216         /* Deallocate any bytes allocated for the length of the WPACKET */
 217         if ((pkt->curr - sub->lenbytes) == sub->packet_len) {
 218             pkt->written -= sub->lenbytes;
 219             pkt->curr -= sub->lenbytes;
 220         }
 221
 222         /* Don't write out the packet length */
 223         sub->packet_len = 0;
 224         sub->lenbytes = 0;
 225     }
 226
 227     /* Write out the WPACKET length if needed */
 228     if (sub->lenbytes > 0) {
 229         unsigned char *buf = GETBUF(pkt);
 230
 231         if (buf != NULL
 232                 && !put_value(&buf[sub->packet_len], packlen,
 233                               sub->lenbytes))
 234             return 0;
 235     }
 236
 237     if (doclose) {
 238         pkt->subs = sub->parent;
 239         OPENSSL_free(sub);
 240     }
 241
 242     return 1;
 243 }
 244
 245 int WPACKET_fill_lengths(WPACKET *pkt)
 246 {
 247     WPACKET_SUB *sub;
 248
 249     if (!ossl_assert(pkt->subs != NULL))
 250         return 0;
 251
 252     for (sub = pkt->subs; sub != NULL; sub = sub->parent) {
 253         if (!wpacket_intern_close(pkt, sub, 0))
 254             return 0;
 255     }
 256
 257     return 1;
 258 }
 259
 260 int WPACKET_close(WPACKET *pkt)
 261 {
 262     /*
 263      * Internal API, so should not fail - but we do negative testing of this
 264      * so no assert (otherwise the tests fail)
 265      */
 266     if (pkt->subs == NULL || pkt->subs->parent == NULL)
 267         return 0;
 268
 269     return wpacket_intern_close(pkt, pkt->subs, 1);
 270 }
 271
 272 int WPACKET_finish(WPACKET *pkt)
 273 {
 274     int ret;
 275
 276     /*
 277      * Internal API, so should not fail - but we do negative testing of this
 278      * so no assert (otherwise the tests fail)
 279      */
 280     if (pkt->subs == NULL || pkt->subs->parent != NULL)
 281         return 0;
 282
 283     ret = wpacket_intern_close(pkt, pkt->subs, 1);
 284     if (ret) {
 285         OPENSSL_free(pkt->subs);
 286         pkt->subs = NULL;
 287     }
 288
 289     return ret;
 290 }
 291
 292 int WPACKET_start_sub_packet_len__(WPACKET *pkt, size_t lenbytes)
 293 {
 294     WPACKET_SUB *sub;
 295     unsigned char *lenchars;
 296
 297     /* Internal API, so should not fail */
 298     if (!ossl_assert(pkt->subs != NULL))
 299         return 0;
 300
 301     if ((sub = OPENSSL_zalloc(sizeof(*sub))) == NULL) {
 302         SSLerr(SSL_F_WPACKET_START_SUB_PACKET_LEN__, ERR_R_MALLOC_FAILURE);
 303         return 0;
 304     }
 305
 306     sub->parent = pkt->subs;
 307     pkt->subs = sub;
 308     sub->pwritten = pkt->written + lenbytes;
 309     sub->lenbytes = lenbytes;
 310
 311     if (lenbytes == 0) {
 312         sub->packet_len = 0;
 313         return 1;
 314     }
 315
 316     sub->packet_len = pkt->written;
 317
 318     if (!WPACKET_allocate_bytes(pkt, lenbytes, &lenchars))
 319         return 0;
 320
 321     return 1;
 322 }
 323
 324 int WPACKET_start_sub_packet(WPACKET *pkt)
 325 {
 326     return WPACKET_start_sub_packet_len__(pkt, 0);
 327 }
 328
 329 int WPACKET_put_bytes__(WPACKET *pkt, unsigned int val, size_t size)
 330 {
 331     unsigned char *data;
 332
 333     /* Internal API, so should not fail */
 334     if (!ossl_assert(size <= sizeof(unsigned int))
 335             || !WPACKET_allocate_bytes(pkt, size, &data)
 336             || !put_value(data, val, size))
 337         return 0;
 338
 339     return 1;
 340 }
 341
 342 int WPACKET_set_max_size(WPACKET *pkt, size_t maxsize)
 343 {
 344     WPACKET_SUB *sub;
 345     size_t lenbytes;
 346
 347     /* Internal API, so should not fail */
 348     if (!ossl_assert(pkt->subs != NULL))
 349         return 0;
 350
 351     /* Find the WPACKET_SUB for the top level */
 352     for (sub = pkt->subs; sub->parent != NULL; sub = sub->parent)
 353         continue;
 354
 355     lenbytes = sub->lenbytes;
 356     if (lenbytes == 0)
 357         lenbytes = sizeof(pkt->maxsize);
 358
 359     if (maxmaxsize(lenbytes) < maxsize || maxsize < pkt->written)
 360         return 0;
 361
 362     pkt->maxsize = maxsize;
 363
 364     return 1;
 365 }
 366
 367 int WPACKET_memset(WPACKET *pkt, int ch, size_t len)
 368 {
 369     unsigned char *dest;
 370
 371     if (len == 0)
 372         return 1;
 373
 374     if (!WPACKET_allocate_bytes(pkt, len, &dest))
 375         return 0;
 376
 377     if (dest != NULL)
 378         memset(dest, ch, len);
 379
 380     return 1;
 381 }
 382
 383 int WPACKET_memcpy(WPACKET *pkt, const void *src, size_t len)
 384 {
 385     unsigned char *dest;
 386
 387     if (len == 0)
 388         return 1;
 389
 390     if (!WPACKET_allocate_bytes(pkt, len, &dest))
 391         return 0;
 392
 393     if (dest != NULL)
 394         memcpy(dest, src, len);
 395
 396     return 1;
 397 }
 398
 399 int WPACKET_sub_memcpy__(WPACKET *pkt, const void *src, size_t len,
 400                          size_t lenbytes)
 401 {
 402     if (!WPACKET_start_sub_packet_len__(pkt, lenbytes)
 403             || !WPACKET_memcpy(pkt, src, len)
 404             || !WPACKET_close(pkt))
 405         return 0;
 406
 407     return 1;
 408 }
 409
 410 int WPACKET_get_total_written(WPACKET *pkt, size_t *written)
 411 {
 412     /* Internal API, so should not fail */
 413     if (!ossl_assert(written != NULL))
 414         return 0;
 415
 416     *written = pkt->written;
 417
 418     return 1;
 419 }
 420
 421 int WPACKET_get_length(WPACKET *pkt, size_t *len)
 422 {
 423     /* Internal API, so should not fail */
 424     if (!ossl_assert(pkt->subs != NULL && len != NULL))
 425         return 0;
 426
 427     *len = pkt->written - pkt->subs->pwritten;
 428
 429     return 1;
 430 }
 431
 432 unsigned char *WPACKET_get_curr(WPACKET *pkt)
 433 {
 434     unsigned char *buf = GETBUF(pkt);
 435
 436     if (buf == NULL)
 437         return NULL;
 438
 439     return buf + pkt->curr;
 440 }
 441
 442 int WPACKET_is_null_buf(WPACKET *pkt)
 443 {
 444     return pkt->buf == NULL && pkt->staticbuf == NULL;
 445 }
 446
 447 void WPACKET_cleanup(WPACKET *pkt)
 448 {
 449     WPACKET_SUB *sub, *parent;
 450
 451     for (sub = pkt->subs; sub != NULL; sub = parent) {
 452         parent = sub->parent;
 453         OPENSSL_free(sub);
 454     }
 455     pkt->subs = NULL;
 456 }