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     /* Internal API, so should not fail */
  18     assert(pkt->subs != NULL && len != 0);
  19     if (pkt->subs == NULL || len == 0)
  20         return 0;
  21
  22     if (pkt->maxsize - pkt->written < len)
  23         return 0;
  24
  25     if (pkt->buf->length - pkt->written < len) {
  26         size_t newlen;
  27
  28         if (pkt->buf->length > SIZE_MAX / 2) {
  29             newlen = SIZE_MAX;
  30         } else {
  31             newlen = (pkt->buf->length == 0) ? DEFAULT_BUF_SIZE
  32                                              : pkt->buf->length * 2;
  33         }
  34         if (BUF_MEM_grow(pkt->buf, newlen) == 0)
  35             return 0;
  36     }
  37     pkt->written += len;
  38     *allocbytes = (unsigned char *)pkt->buf->data + pkt->curr;
  39     pkt->curr += len;
  40
  41     return 1;
  42 }
  43
  44 static size_t maxmaxsize(size_t lenbytes)
  45 {
  46     if (lenbytes >= sizeof(size_t) || lenbytes == 0)
  47         return SIZE_MAX;
  48     else
  49         return ((size_t)1 << (lenbytes * 8)) - 1 + lenbytes;
  50 }
  51
  52 int WPACKET_init_len(WPACKET *pkt, BUF_MEM *buf, size_t lenbytes)
  53 {
  54     unsigned char *lenchars;
  55
  56     /* Internal API, so should not fail */
  57     assert(buf != NULL);
  58     if (buf == NULL)
  59         return 0;
  60
  61     pkt->buf = buf;
  62     pkt->curr = 0;
  63     pkt->written = 0;
  64     pkt->maxsize = maxmaxsize(lenbytes);
  65
  66     pkt->subs = OPENSSL_zalloc(sizeof(*pkt->subs));
  67     if (pkt->subs == NULL)
  68         return 0;
  69
  70     if (lenbytes == 0)
  71         return 1;
  72
  73     pkt->subs->pwritten = lenbytes;
  74     pkt->subs->lenbytes = lenbytes;
  75
  76     if (!WPACKET_allocate_bytes(pkt, lenbytes, &lenchars)) {
  77         OPENSSL_free(pkt->subs);
  78         pkt->subs = NULL;
  79         return 0;
  80     }
  81     pkt->subs->packet_len = lenchars - (unsigned char *)pkt->buf->data;
  82
  83     return 1;
  84 }
  85
  86 int WPACKET_init(WPACKET *pkt, BUF_MEM *buf)
  87 {
  88     return WPACKET_init_len(pkt, buf, 0);
  89 }
  90
  91 int WPACKET_set_flags(WPACKET *pkt, unsigned int flags)
  92 {
  93     /* Internal API, so should not fail */
  94     assert(pkt->subs != NULL);
  95     if (pkt->subs == NULL)
  96         return 0;
  97
  98     pkt->subs->flags = flags;
  99
 100     return 1;
 101 }
 102
 103 /* Store the |value| of length |size| at location |data| */
 104 static int put_value(unsigned char *data, size_t value, size_t size)
 105 {
 106     for (data += size - 1; size > 0; size--) {
 107         *data = (unsigned char)(value & 0xff);
 108         data--;
 109         value >>= 8;
 110     }
 111
 112     /* Check whether we could fit the value in the assigned number of bytes */
 113     if (value > 0)
 114         return 0;
 115
 116     return 1;
 117 }
 118
 119
 120 /*
 121  * Internal helper function used by WPACKET_close() and WPACKET_finish() to
 122  * close a sub-packet and write out its length if necessary.
 123  */
 124 static int wpacket_intern_close(WPACKET *pkt)
 125 {
 126     WPACKET_SUB *sub = pkt->subs;
 127     size_t packlen = pkt->written - sub->pwritten;
 128
 129     if (packlen == 0
 130             && sub->flags & WPACKET_FLAGS_NON_ZERO_LENGTH)
 131         return 0;
 132
 133     if (packlen == 0
 134             && sub->flags & WPACKET_FLAGS_ABANDON_ON_ZERO_LENGTH) {
 135         /* Deallocate any bytes allocated for the length of the WPACKET */
 136         if ((pkt->curr - sub->lenbytes) == sub->packet_len) {
 137             pkt->written -= sub->lenbytes;
 138             pkt->curr -= sub->lenbytes;
 139         }
 140
 141         /* Don't write out the packet length */
 142         sub->packet_len = 0;
 143         sub->lenbytes = 0;
 144     }
 145
 146     /* Write out the WPACKET length if needed */
 147     if (sub->lenbytes > 0
 148                 && !put_value((unsigned char *)&pkt->buf->data[sub->packet_len],
 149                               packlen, sub->lenbytes))
 150             return 0;
 151
 152     pkt->subs = sub->parent;
 153     OPENSSL_free(sub);
 154
 155     return 1;
 156 }
 157
 158 int WPACKET_close(WPACKET *pkt)
 159 {
 160     /*
 161      * Internal API, so should not fail - but we do negative testing of this
 162      * so no assert (otherwise the tests fail)
 163      */
 164     if (pkt->subs == NULL || pkt->subs->parent == NULL)
 165         return 0;
 166
 167     return wpacket_intern_close(pkt);
 168 }
 169
 170 int WPACKET_finish(WPACKET *pkt)
 171 {
 172     int ret;
 173
 174     /*
 175      * Internal API, so should not fail - but we do negative testing of this
 176      * so no assert (otherwise the tests fail)
 177      */
 178     if (pkt->subs == NULL || pkt->subs->parent != NULL)
 179         return 0;
 180
 181     ret = wpacket_intern_close(pkt);
 182     if (ret) {
 183         OPENSSL_free(pkt->subs);
 184         pkt->subs = NULL;
 185     }
 186
 187     return ret;
 188 }
 189
 190 int WPACKET_start_sub_packet_len(WPACKET *pkt, size_t lenbytes)
 191 {
 192     WPACKET_SUB *sub;
 193     unsigned char *lenchars;
 194
 195     /* Internal API, so should not fail */
 196     assert(pkt->subs != NULL);
 197     if (pkt->subs == NULL)
 198         return 0;
 199
 200     sub = OPENSSL_zalloc(sizeof(*sub));
 201     if (sub == NULL)
 202         return 0;
 203
 204     sub->parent = pkt->subs;
 205     pkt->subs = sub;
 206     sub->pwritten = pkt->written + lenbytes;
 207     sub->lenbytes = lenbytes;
 208
 209     if (lenbytes == 0) {
 210         sub->packet_len = 0;
 211         return 1;
 212     }
 213
 214     if (!WPACKET_allocate_bytes(pkt, lenbytes, &lenchars))
 215         return 0;
 216     sub->packet_len = lenchars - (unsigned char *)pkt->buf->data;
 217
 218     return 1;
 219 }
 220
 221 int WPACKET_start_sub_packet(WPACKET *pkt)
 222 {
 223     return WPACKET_start_sub_packet_len(pkt, 0);
 224 }
 225
 226 int WPACKET_put_bytes(WPACKET *pkt, unsigned int val, size_t size)
 227 {
 228     unsigned char *data;
 229
 230     /* Internal API, so should not fail */
 231     assert(size <= sizeof(unsigned int));
 232     if (size > sizeof(unsigned int)
 233             || !WPACKET_allocate_bytes(pkt, size, &data)
 234             || !put_value(data, val, size))
 235         return 0;
 236
 237     return 1;
 238 }
 239
 240 int WPACKET_set_max_size(WPACKET *pkt, size_t maxsize)
 241 {
 242     WPACKET_SUB *sub;
 243     size_t lenbytes;
 244
 245     /* Internal API, so should not fail */
 246     assert(pkt->subs != NULL);
 247     if (pkt->subs == NULL)
 248         return 0;
 249
 250     /* Find the WPACKET_SUB for the top level */
 251     for (sub = pkt->subs; sub->parent != NULL; sub = sub->parent)
 252         continue;
 253
 254     lenbytes = sub->lenbytes;
 255     if (lenbytes == 0)
 256         lenbytes = sizeof(pkt->maxsize);
 257
 258     if (maxmaxsize(lenbytes) < maxsize || maxsize < pkt->written)
 259         return 0;
 260
 261     pkt->maxsize = maxsize;
 262
 263     return 1;
 264 }
 265
 266 int WPACKET_memcpy(WPACKET *pkt, const void *src, size_t len)
 267 {
 268     unsigned char *dest;
 269
 270     if (len == 0)
 271         return 1;
 272
 273     if (!WPACKET_allocate_bytes(pkt, len, &dest))
 274         return 0;
 275
 276     memcpy(dest, src, len);
 277
 278     return 1;
 279 }
 280
 281 int WPACKET_sub_memcpy(WPACKET *pkt, const void *src, size_t len, size_t lenbytes)
 282 {
 283     if (!WPACKET_start_sub_packet_len(pkt, lenbytes)
 284             || !WPACKET_memcpy(pkt, src, len)
 285             || !WPACKET_close(pkt))
 286         return 0;
 287
 288     return 1;
 289 }
 290
 291 int WPACKET_get_total_written(WPACKET *pkt, size_t *written)
 292 {
 293     /* Internal API, so should not fail */
 294     assert(written != NULL);
 295     if (written == NULL)
 296         return 0;
 297
 298     *written = pkt->written;
 299
 300     return 1;
 301 }
 302
 303 int WPACKET_get_length(WPACKET *pkt, size_t *len)
 304 {
 305     /* Internal API, so should not fail */
 306     assert(pkt->subs != NULL && len != NULL);
 307     if (pkt->subs == NULL || len == NULL)
 308         return 0;
 309
 310     *len = pkt->written - pkt->subs->pwritten;
 311
 312     return 1;
 313 }
 314
 315 void WPACKET_cleanup(WPACKET *pkt)
 316 {
 317     WPACKET_SUB *sub, *parent;
 318
 319     for (sub = pkt->subs; sub != NULL; sub = parent) {
 320         parent = sub->parent;
 321         OPENSSL_free(sub);
 322     }
 323     pkt->subs = NULL;
 324 }