ssl/packet.c

   1 /*
   2  * Copyright 2015-2016 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the OpenSSL license (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 <assert.h>
  11 #include "packet_locl.h"
  12
  13 #define DEFAULT_BUF_SIZE    256
  14
  15 int WPACKET_allocate_bytes(WPACKET *pkt, size_t len, unsigned char **allocbytes)
  16 {
  17     if (!WPACKET_reserve_bytes(pkt, len, allocbytes))
  18         return 0;
  19
  20     pkt->written += len;
  21     pkt->curr += len;
  22     return 1;
  23 }
  24
  25 int WPACKET_sub_allocate_bytes__(WPACKET *pkt, size_t len,
  26                                  unsigned char **allocbytes, size_t lenbytes)
  27 {
  28     if (!WPACKET_start_sub_packet_len__(pkt, lenbytes)
  29             || !WPACKET_allocate_bytes(pkt, len, allocbytes)
  30             || !WPACKET_close(pkt))
  31         return 0;
  32
  33     return 1;
  34 }
  35
  36 #define GETBUF(p)   (((p)->staticbuf != NULL) \
  37                      ? (p)->staticbuf : (unsigned char *)(p)->buf->data)
  38
  39 int WPACKET_reserve_bytes(WPACKET *pkt, size_t len, unsigned char **allocbytes)
  40 {
  41     /* Internal API, so should not fail */
  42     assert(pkt->subs != NULL && len != 0);
  43     if (pkt->subs == NULL || len == 0)
  44         return 0;
  45
  46     if (pkt->maxsize - pkt->written < len)
  47         return 0;
  48
  49     if (pkt->staticbuf == NULL && (pkt->buf->length - pkt->written < len)) {
  50         size_t newlen;
  51         size_t reflen;
  52
  53         reflen = (len > pkt->buf->length) ? len : pkt->buf->length;
  54
  55         if (reflen > SIZE_MAX / 2) {
  56             newlen = SIZE_MAX;
  57         } else {
  58             newlen = reflen * 2;
  59             if (newlen < DEFAULT_BUF_SIZE)
  60                 newlen = DEFAULT_BUF_SIZE;
  61         }
  62         if (BUF_MEM_grow(pkt->buf, newlen) == 0)
  63             return 0;
  64     }
  65     if (allocbytes != NULL)
  66         *allocbytes = WPACKET_get_curr(pkt);
  67
  68     return 1;
  69 }
  70
  71 int WPACKET_sub_reserve_bytes__(WPACKET *pkt, size_t len,
  72                                 unsigned char **allocbytes, size_t lenbytes)
  73 {
  74     if (!WPACKET_reserve_bytes(pkt, lenbytes + len, allocbytes))
  75         return 0;
  76
  77     *allocbytes += lenbytes;
  78
  79     return 1;
  80 }
  81
  82 static size_t maxmaxsize(size_t lenbytes)
  83 {
  84     if (lenbytes >= sizeof(size_t) || lenbytes == 0)
  85         return SIZE_MAX;
  86
  87     return ((size_t)1 << (lenbytes * 8)) - 1 + lenbytes;
  88 }
  89
  90 static int wpacket_intern_init_len(WPACKET *pkt, size_t lenbytes)
  91 {
  92     unsigned char *lenchars;
  93
  94     pkt->curr = 0;
  95     pkt->written = 0;
  96
  97     pkt->subs = OPENSSL_zalloc(sizeof(*pkt->subs));
  98     if (pkt->subs == NULL)
  99         return 0;
 100
 101     if (lenbytes == 0)
 102         return 1;
 103
 104     pkt->subs->pwritten = lenbytes;
 105     pkt->subs->lenbytes = lenbytes;
 106
 107     if (!WPACKET_allocate_bytes(pkt, lenbytes, &lenchars)) {
 108         OPENSSL_free(pkt->subs);
 109         pkt->subs = NULL;
 110         return 0;
 111     }
 112     pkt->subs->packet_len = lenchars - GETBUF(pkt);
 113
 114     return 1;
 115 }
 116
 117 int WPACKET_init_static_len(WPACKET *pkt, unsigned char *buf, size_t len,
 118                             size_t lenbytes)
 119 {
 120     size_t max = maxmaxsize(lenbytes);
 121
 122     /* Internal API, so should not fail */
 123     assert(buf != NULL && len > 0);
 124     if (buf == NULL || len == 0)
 125         return 0;
 126
 127     pkt->staticbuf = buf;
 128     pkt->buf = NULL;
 129     pkt->maxsize = (max < len) ? max : len;
 130
 131     return wpacket_intern_init_len(pkt, lenbytes);
 132 }
 133
 134 int WPACKET_init_len(WPACKET *pkt, BUF_MEM *buf, size_t lenbytes)
 135 {
 136     /* Internal API, so should not fail */
 137     assert(buf != NULL);
 138     if (buf == NULL)
 139         return 0;
 140
 141     pkt->staticbuf = NULL;
 142     pkt->buf = buf;
 143     pkt->maxsize = maxmaxsize(lenbytes);
 144
 145     return wpacket_intern_init_len(pkt, lenbytes);
 146 }
 147
 148 int WPACKET_init(WPACKET *pkt, BUF_MEM *buf)
 149 {
 150     return WPACKET_init_len(pkt, buf, 0);
 151 }
 152
 153 int WPACKET_set_flags(WPACKET *pkt, unsigned int flags)
 154 {
 155     /* Internal API, so should not fail */
 156     assert(pkt->subs != NULL);
 157     if (pkt->subs == NULL)
 158         return 0;
 159
 160     pkt->subs->flags = flags;
 161
 162     return 1;
 163 }
 164
 165 /* Store the |value| of length |len| at location |data| */
 166 static int put_value(unsigned char *data, size_t value, size_t len)
 167 {
 168     for (data += len - 1; len > 0; len--) {
 169         *data = (unsigned char)(value & 0xff);
 170         data--;
 171         value >>= 8;
 172     }
 173
 174     /* Check whether we could fit the value in the assigned number of bytes */
 175     if (value > 0)
 176         return 0;
 177
 178     return 1;
 179 }
 180
 181
 182 /*
 183  * Internal helper function used by WPACKET_close(), WPACKET_finish() and
 184  * WPACKET_fill_lengths() to close a sub-packet and write out its length if
 185  * necessary. If |doclose| is 0 then it goes through the motions of closing
 186  * (i.e. it fills in all the lengths), but doesn't actually close anything.
 187  */
 188 static int wpacket_intern_close(WPACKET *pkt, WPACKET_SUB *sub, int doclose)
 189 {
 190     size_t packlen = pkt->written - sub->pwritten;
 191
 192     if (packlen == 0
 193             && (sub->flags & WPACKET_FLAGS_NON_ZERO_LENGTH) != 0)
 194         return 0;
 195
 196     if (packlen == 0
 197             && sub->flags & WPACKET_FLAGS_ABANDON_ON_ZERO_LENGTH) {
 198         /* We can't handle this case. Return an error */
 199         if (!doclose)
 200             return 0;
 201
 202         /* Deallocate any bytes allocated for the length of the WPACKET */
 203         if ((pkt->curr - sub->lenbytes) == sub->packet_len) {
 204             pkt->written -= sub->lenbytes;
 205             pkt->curr -= sub->lenbytes;
 206         }
 207
 208         /* Don't write out the packet length */
 209         sub->packet_len = 0;
 210         sub->lenbytes = 0;
 211     }
 212
 213     /* Write out the WPACKET length if needed */
 214     if (sub->lenbytes > 0
 215                 && !put_value(&GETBUF(pkt)[sub->packet_len], packlen,
 216                               sub->lenbytes))
 217             return 0;
 218
 219     if (doclose) {
 220         pkt->subs = sub->parent;
 221         OPENSSL_free(sub);
 222     }
 223
 224     return 1;
 225 }
 226
 227 int WPACKET_fill_lengths(WPACKET *pkt)
 228 {
 229     WPACKET_SUB *sub;
 230
 231     assert(pkt->subs != NULL);
 232     if (pkt->subs == NULL)
 233         return 0;
 234
 235     for (sub = pkt->subs; sub != NULL; sub = sub->parent) {
 236         if (!wpacket_intern_close(pkt, sub, 0))
 237             return 0;
 238     }
 239
 240     return 1;
 241 }
 242
 243 int WPACKET_close(WPACKET *pkt)
 244 {
 245     /*
 246      * Internal API, so should not fail - but we do negative testing of this
 247      * so no assert (otherwise the tests fail)
 248      */
 249     if (pkt->subs == NULL || pkt->subs->parent == NULL)
 250         return 0;
 251
 252     return wpacket_intern_close(pkt, pkt->subs, 1);
 253 }
 254
 255 int WPACKET_finish(WPACKET *pkt)
 256 {
 257     int ret;
 258
 259     /*
 260      * Internal API, so should not fail - but we do negative testing of this
 261      * so no assert (otherwise the tests fail)
 262      */
 263     if (pkt->subs == NULL || pkt->subs->parent != NULL)
 264         return 0;
 265
 266     ret = wpacket_intern_close(pkt, pkt->subs, 1);
 267     if (ret) {
 268         OPENSSL_free(pkt->subs);
 269         pkt->subs = NULL;
 270     }
 271
 272     return ret;
 273 }
 274
 275 int WPACKET_start_sub_packet_len__(WPACKET *pkt, size_t lenbytes)
 276 {
 277     WPACKET_SUB *sub;
 278     unsigned char *lenchars;
 279
 280     /* Internal API, so should not fail */
 281     assert(pkt->subs != NULL);
 282     if (pkt->subs == NULL)
 283         return 0;
 284
 285     sub = OPENSSL_zalloc(sizeof(*sub));
 286     if (sub == NULL)
 287         return 0;
 288
 289     sub->parent = pkt->subs;
 290     pkt->subs = sub;
 291     sub->pwritten = pkt->written + lenbytes;
 292     sub->lenbytes = lenbytes;
 293
 294     if (lenbytes == 0) {
 295         sub->packet_len = 0;
 296         return 1;
 297     }
 298
 299     if (!WPACKET_allocate_bytes(pkt, lenbytes, &lenchars))
 300         return 0;
 301     /* Convert to an offset in case the underlying BUF_MEM gets realloc'd */
 302     sub->packet_len = lenchars - GETBUF(pkt);
 303
 304     return 1;
 305 }
 306
 307 int WPACKET_start_sub_packet(WPACKET *pkt)
 308 {
 309     return WPACKET_start_sub_packet_len__(pkt, 0);
 310 }
 311
 312 int WPACKET_put_bytes__(WPACKET *pkt, unsigned int val, size_t size)
 313 {
 314     unsigned char *data;
 315
 316     /* Internal API, so should not fail */
 317     assert(size <= sizeof(unsigned int));
 318
 319     if (size > sizeof(unsigned int)
 320             || !WPACKET_allocate_bytes(pkt, size, &data)
 321             || !put_value(data, val, size))
 322         return 0;
 323
 324     return 1;
 325 }
 326
 327 int WPACKET_set_max_size(WPACKET *pkt, size_t maxsize)
 328 {
 329     WPACKET_SUB *sub;
 330     size_t lenbytes;
 331
 332     /* Internal API, so should not fail */
 333     assert(pkt->subs != NULL);
 334     if (pkt->subs == NULL)
 335         return 0;
 336
 337     /* Find the WPACKET_SUB for the top level */
 338     for (sub = pkt->subs; sub->parent != NULL; sub = sub->parent)
 339         continue;
 340
 341     lenbytes = sub->lenbytes;
 342     if (lenbytes == 0)
 343         lenbytes = sizeof(pkt->maxsize);
 344
 345     if (maxmaxsize(lenbytes) < maxsize || maxsize < pkt->written)
 346         return 0;
 347
 348     pkt->maxsize = maxsize;
 349
 350     return 1;
 351 }
 352
 353 int WPACKET_memset(WPACKET *pkt, int ch, size_t len)
 354 {
 355     unsigned char *dest;
 356
 357     if (len == 0)
 358         return 1;
 359
 360     if (!WPACKET_allocate_bytes(pkt, len, &dest))
 361         return 0;
 362
 363     memset(dest, ch, len);
 364
 365     return 1;
 366 }
 367
 368 int WPACKET_memcpy(WPACKET *pkt, const void *src, size_t len)
 369 {
 370     unsigned char *dest;
 371
 372     if (len == 0)
 373         return 1;
 374
 375     if (!WPACKET_allocate_bytes(pkt, len, &dest))
 376         return 0;
 377
 378     memcpy(dest, src, len);
 379
 380     return 1;
 381 }
 382
 383 int WPACKET_sub_memcpy__(WPACKET *pkt, const void *src, size_t len,
 384                          size_t lenbytes)
 385 {
 386     if (!WPACKET_start_sub_packet_len__(pkt, lenbytes)
 387             || !WPACKET_memcpy(pkt, src, len)
 388             || !WPACKET_close(pkt))
 389         return 0;
 390
 391     return 1;
 392 }
 393
 394 int WPACKET_get_total_written(WPACKET *pkt, size_t *written)
 395 {
 396     /* Internal API, so should not fail */
 397     assert(written != NULL);
 398     if (written == NULL)
 399         return 0;
 400
 401     *written = pkt->written;
 402
 403     return 1;
 404 }
 405
 406 int WPACKET_get_length(WPACKET *pkt, size_t *len)
 407 {
 408     /* Internal API, so should not fail */
 409     assert(pkt->subs != NULL && len != NULL);
 410     if (pkt->subs == NULL || len == NULL)
 411         return 0;
 412
 413     *len = pkt->written - pkt->subs->pwritten;
 414
 415     return 1;
 416 }
 417
 418 unsigned char *WPACKET_get_curr(WPACKET *pkt)
 419 {
 420     return GETBUF(pkt) + pkt->curr;
 421 }
 422
 423 void WPACKET_cleanup(WPACKET *pkt)
 424 {
 425     WPACKET_SUB *sub, *parent;
 426
 427     for (sub = pkt->subs; sub != NULL; sub = parent) {
 428         parent = sub->parent;
 429         OPENSSL_free(sub);
 430     }
 431     pkt->subs = NULL;
 432 }