ssl/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 "packet_locl.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 : (unsigned char *)(p)->buf->data)
  39
  40 int WPACKET_reserve_bytes(WPACKET *pkt, size_t len, unsigned char **allocbytes)
  41 {
  42     /* Internal API, so should not fail */
  43     if (!ossl_assert(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     if ((pkt->subs = OPENSSL_zalloc(sizeof(*pkt->subs))) == NULL) {
  98         SSLerr(SSL_F_WPACKET_INTERN_INIT_LEN, ERR_R_MALLOC_FAILURE);
  99         return 0;
 100     }
 101
 102     if (lenbytes == 0)
 103         return 1;
 104
 105     pkt->subs->pwritten = lenbytes;
 106     pkt->subs->lenbytes = lenbytes;
 107
 108     if (!WPACKET_allocate_bytes(pkt, lenbytes, &lenchars)) {
 109         OPENSSL_free(pkt->subs);
 110         pkt->subs = NULL;
 111         return 0;
 112     }
 113     pkt->subs->packet_len = lenchars - GETBUF(pkt);
 114
 115     return 1;
 116 }
 117
 118 int WPACKET_init_static_len(WPACKET *pkt, unsigned char *buf, size_t len,
 119                             size_t lenbytes)
 120 {
 121     size_t max = maxmaxsize(lenbytes);
 122
 123     /* Internal API, so should not fail */
 124     if (!ossl_assert(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     if (!ossl_assert(buf != NULL))
 138         return 0;
 139
 140     pkt->staticbuf = NULL;
 141     pkt->buf = buf;
 142     pkt->maxsize = maxmaxsize(lenbytes);
 143
 144     return wpacket_intern_init_len(pkt, lenbytes);
 145 }
 146
 147 int WPACKET_init(WPACKET *pkt, BUF_MEM *buf)
 148 {
 149     return WPACKET_init_len(pkt, buf, 0);
 150 }
 151
 152 int WPACKET_set_flags(WPACKET *pkt, unsigned int flags)
 153 {
 154     /* Internal API, so should not fail */
 155     if (!ossl_assert(pkt->subs != NULL))
 156         return 0;
 157
 158     pkt->subs->flags = flags;
 159
 160     return 1;
 161 }
 162
 163 /* Store the |value| of length |len| at location |data| */
 164 static int put_value(unsigned char *data, size_t value, size_t len)
 165 {
 166     for (data += len - 1; len > 0; len--) {
 167         *data = (unsigned char)(value & 0xff);
 168         data--;
 169         value >>= 8;
 170     }
 171
 172     /* Check whether we could fit the value in the assigned number of bytes */
 173     if (value > 0)
 174         return 0;
 175
 176     return 1;
 177 }
 178
 179
 180 /*
 181  * Internal helper function used by WPACKET_close(), WPACKET_finish() and
 182  * WPACKET_fill_lengths() to close a sub-packet and write out its length if
 183  * necessary. If |doclose| is 0 then it goes through the motions of closing
 184  * (i.e. it fills in all the lengths), but doesn't actually close anything.
 185  */
 186 static int wpacket_intern_close(WPACKET *pkt, WPACKET_SUB *sub, int doclose)
 187 {
 188     size_t packlen = pkt->written - sub->pwritten;
 189
 190     if (packlen == 0
 191             && (sub->flags & WPACKET_FLAGS_NON_ZERO_LENGTH) != 0)
 192         return 0;
 193
 194     if (packlen == 0
 195             && sub->flags & WPACKET_FLAGS_ABANDON_ON_ZERO_LENGTH) {
 196         /* We can't handle this case. Return an error */
 197         if (!doclose)
 198             return 0;
 199
 200         /* Deallocate any bytes allocated for the length of the WPACKET */
 201         if ((pkt->curr - sub->lenbytes) == sub->packet_len) {
 202             pkt->written -= sub->lenbytes;
 203             pkt->curr -= sub->lenbytes;
 204         }
 205
 206         /* Don't write out the packet length */
 207         sub->packet_len = 0;
 208         sub->lenbytes = 0;
 209     }
 210
 211     /* Write out the WPACKET length if needed */
 212     if (sub->lenbytes > 0
 213                 && !put_value(&GETBUF(pkt)[sub->packet_len], packlen,
 214                               sub->lenbytes))
 215             return 0;
 216
 217     if (doclose) {
 218         pkt->subs = sub->parent;
 219         OPENSSL_free(sub);
 220     }
 221
 222     return 1;
 223 }
 224
 225 int WPACKET_fill_lengths(WPACKET *pkt)
 226 {
 227     WPACKET_SUB *sub;
 228
 229     if (!ossl_assert(pkt->subs != NULL))
 230         return 0;
 231
 232     for (sub = pkt->subs; sub != NULL; sub = sub->parent) {
 233         if (!wpacket_intern_close(pkt, sub, 0))
 234             return 0;
 235     }
 236
 237     return 1;
 238 }
 239
 240 int WPACKET_close(WPACKET *pkt)
 241 {
 242     /*
 243      * Internal API, so should not fail - but we do negative testing of this
 244      * so no assert (otherwise the tests fail)
 245      */
 246     if (pkt->subs == NULL || pkt->subs->parent == NULL)
 247         return 0;
 248
 249     return wpacket_intern_close(pkt, pkt->subs, 1);
 250 }
 251
 252 int WPACKET_finish(WPACKET *pkt)
 253 {
 254     int ret;
 255
 256     /*
 257      * Internal API, so should not fail - but we do negative testing of this
 258      * so no assert (otherwise the tests fail)
 259      */
 260     if (pkt->subs == NULL || pkt->subs->parent != NULL)
 261         return 0;
 262
 263     ret = wpacket_intern_close(pkt, pkt->subs, 1);
 264     if (ret) {
 265         OPENSSL_free(pkt->subs);
 266         pkt->subs = NULL;
 267     }
 268
 269     return ret;
 270 }
 271
 272 int WPACKET_start_sub_packet_len__(WPACKET *pkt, size_t lenbytes)
 273 {
 274     WPACKET_SUB *sub;
 275     unsigned char *lenchars;
 276
 277     /* Internal API, so should not fail */
 278     if (!ossl_assert(pkt->subs != NULL))
 279         return 0;
 280
 281     if ((sub = OPENSSL_zalloc(sizeof(*sub))) == NULL) {
 282         SSLerr(SSL_F_WPACKET_START_SUB_PACKET_LEN__, ERR_R_MALLOC_FAILURE);
 283         return 0;
 284     }
 285
 286     sub->parent = pkt->subs;
 287     pkt->subs = sub;
 288     sub->pwritten = pkt->written + lenbytes;
 289     sub->lenbytes = lenbytes;
 290
 291     if (lenbytes == 0) {
 292         sub->packet_len = 0;
 293         return 1;
 294     }
 295
 296     if (!WPACKET_allocate_bytes(pkt, lenbytes, &lenchars))
 297         return 0;
 298     /* Convert to an offset in case the underlying BUF_MEM gets realloc'd */
 299     sub->packet_len = lenchars - GETBUF(pkt);
 300
 301     return 1;
 302 }
 303
 304 int WPACKET_start_sub_packet(WPACKET *pkt)
 305 {
 306     return WPACKET_start_sub_packet_len__(pkt, 0);
 307 }
 308
 309 int WPACKET_put_bytes__(WPACKET *pkt, unsigned int val, size_t size)
 310 {
 311     unsigned char *data;
 312
 313     /* Internal API, so should not fail */
 314     if (!ossl_assert(size <= sizeof(unsigned int))
 315             || !WPACKET_allocate_bytes(pkt, size, &data)
 316             || !put_value(data, val, size))
 317         return 0;
 318
 319     return 1;
 320 }
 321
 322 int WPACKET_set_max_size(WPACKET *pkt, size_t maxsize)
 323 {
 324     WPACKET_SUB *sub;
 325     size_t lenbytes;
 326
 327     /* Internal API, so should not fail */
 328     if (!ossl_assert(pkt->subs != NULL))
 329         return 0;
 330
 331     /* Find the WPACKET_SUB for the top level */
 332     for (sub = pkt->subs; sub->parent != NULL; sub = sub->parent)
 333         continue;
 334
 335     lenbytes = sub->lenbytes;
 336     if (lenbytes == 0)
 337         lenbytes = sizeof(pkt->maxsize);
 338
 339     if (maxmaxsize(lenbytes) < maxsize || maxsize < pkt->written)
 340         return 0;
 341
 342     pkt->maxsize = maxsize;
 343
 344     return 1;
 345 }
 346
 347 int WPACKET_memset(WPACKET *pkt, int ch, size_t len)
 348 {
 349     unsigned char *dest;
 350
 351     if (len == 0)
 352         return 1;
 353
 354     if (!WPACKET_allocate_bytes(pkt, len, &dest))
 355         return 0;
 356
 357     memset(dest, ch, len);
 358
 359     return 1;
 360 }
 361
 362 int WPACKET_memcpy(WPACKET *pkt, const void *src, size_t len)
 363 {
 364     unsigned char *dest;
 365
 366     if (len == 0)
 367         return 1;
 368
 369     if (!WPACKET_allocate_bytes(pkt, len, &dest))
 370         return 0;
 371
 372     memcpy(dest, src, len);
 373
 374     return 1;
 375 }
 376
 377 int WPACKET_sub_memcpy__(WPACKET *pkt, const void *src, size_t len,
 378                          size_t lenbytes)
 379 {
 380     if (!WPACKET_start_sub_packet_len__(pkt, lenbytes)
 381             || !WPACKET_memcpy(pkt, src, len)
 382             || !WPACKET_close(pkt))
 383         return 0;
 384
 385     return 1;
 386 }
 387
 388 int WPACKET_get_total_written(WPACKET *pkt, size_t *written)
 389 {
 390     /* Internal API, so should not fail */
 391     if (!ossl_assert(written != NULL))
 392         return 0;
 393
 394     *written = pkt->written;
 395
 396     return 1;
 397 }
 398
 399 int WPACKET_get_length(WPACKET *pkt, size_t *len)
 400 {
 401     /* Internal API, so should not fail */
 402     if (!ossl_assert(pkt->subs != NULL && len != NULL))
 403         return 0;
 404
 405     *len = pkt->written - pkt->subs->pwritten;
 406
 407     return 1;
 408 }
 409
 410 unsigned char *WPACKET_get_curr(WPACKET *pkt)
 411 {
 412     return GETBUF(pkt) + pkt->curr;
 413 }
 414
 415 void WPACKET_cleanup(WPACKET *pkt)
 416 {
 417     WPACKET_SUB *sub, *parent;
 418
 419     for (sub = pkt->subs; sub != NULL; sub = parent) {
 420         parent = sub->parent;
 421         OPENSSL_free(sub);
 422     }
 423     pkt->subs = NULL;
 424 }