2 * Copyright 2015-2016 The OpenSSL Project Authors. All Rights Reserved.
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
10 #include "packet_locl.h"
12 #define DEFAULT_BUF_SIZE 256
15 * Allocate bytes in the WPACKET for the output. This reserves the bytes
16 * and count them as "written", but doesn't actually do the writing.
18 int WPACKET_allocate_bytes(WPACKET *pkt, size_t len, unsigned char **allocbytes)
20 if (pkt->subs == NULL || len == 0)
23 if (SIZE_MAX - pkt->written < len)
26 if (pkt->written + len > pkt->maxsize)
29 if (pkt->buf->length - pkt->written < len) {
32 if (pkt->buf->length > SIZE_MAX / 2) {
35 if (pkt->buf->length == 0)
36 newlen = DEFAULT_BUF_SIZE;
38 newlen = pkt->buf->length * 2;
40 if (BUF_MEM_grow(pkt->buf, newlen) == 0)
42 if (pkt->curr == NULL) {
44 * Can happen if initialised with a BUF_MEM that hasn't been
47 pkt->curr = (unsigned char *)pkt->buf->data;
51 *allocbytes = pkt->curr;
57 static size_t maxmaxsize(size_t lenbytes)
59 if (lenbytes >= sizeof(size_t) || lenbytes == 0)
62 return ((size_t)1 << (lenbytes * 8)) - 1 + lenbytes;
66 * Initialise a WPACKET with the buffer in |buf|. The buffer must exist
67 * for the whole time that the WPACKET is being used. Additionally |lenbytes| of
68 * data is preallocated at the start of the buffer to store the length of the
69 * WPACKET once we know it.
71 int WPACKET_init_len(WPACKET *pkt, BUF_MEM *buf, size_t lenbytes)
78 pkt->curr = (unsigned char *)buf->data;
80 pkt->maxsize = maxmaxsize(lenbytes);
82 pkt->subs = OPENSSL_zalloc(sizeof(*pkt->subs));
83 if (pkt->subs == NULL)
89 pkt->subs->pwritten = lenbytes;
90 pkt->subs->lenbytes = lenbytes;
92 if (!WPACKET_allocate_bytes(pkt, lenbytes, &(pkt->subs->packet_len))) {
93 OPENSSL_free(pkt->subs);
102 * Same as WPACKET_init_len except there is no preallocation of the WPACKET
105 int WPACKET_init(WPACKET *pkt, BUF_MEM *buf)
107 return WPACKET_init_len(pkt, buf, 0);
111 * Set the WPACKET length, and the location for where we should write that
112 * length. Normally this will be at the start of the WPACKET, and therefore
113 * the WPACKET would have been initialised via WPACKET_init_len(). However there
114 * is the possibility that the length needs to be written to some other location
115 * other than the start of the WPACKET. In that case init via WPACKET_init() and
116 * then set the location for the length using this function.
118 int WPACKET_set_packet_len(WPACKET *pkt, unsigned char *packet_len,
123 /* We only allow this to be set once */
124 if (pkt->subs == NULL || pkt->subs->lenbytes != 0)
127 pkt->subs->lenbytes = lenbytes;
128 pkt->subs->packet_len = packet_len;
130 maxmax = maxmaxsize(lenbytes);
131 if (pkt->maxsize > maxmax)
132 pkt->maxsize = maxmax;
137 int WPACKET_set_flags(WPACKET *pkt, unsigned int flags)
139 if (pkt->subs == NULL)
142 pkt->subs->flags = flags;
149 * Internal helper function used by WPACKET_close() and WPACKET_finish() to
150 * close a sub-packet and write out its length if necessary.
152 static int wpacket_intern_close(WPACKET *pkt)
155 WPACKET_SUB *sub = pkt->subs;
157 packlen = pkt->written - sub->pwritten;
159 && sub->flags & OPENSSL_WPACKET_FLAGS_NON_ZERO_LENGTH)
163 && sub->flags & OPENSSL_WPACKET_FLAGS_ABANDON_ON_ZERO_LENGTH) {
164 /* Deallocate any bytes allocated for the length of the WPACKET */
165 if ((pkt->curr - sub->lenbytes) == sub->packet_len) {
166 pkt->written -= sub->lenbytes;
167 pkt->curr -= sub->lenbytes;
170 /* Don't write out the packet length */
171 sub->packet_len = NULL;
174 /* Write out the WPACKET length if needed */
175 if (sub->packet_len != NULL) {
178 lenbytes = sub->lenbytes;
180 for (; lenbytes > 0; lenbytes--) {
181 sub->packet_len[lenbytes - 1]
182 = (unsigned char)(packlen & 0xff);
187 * We've extended beyond the max allowed for the number of len bytes
193 pkt->subs = sub->parent;
200 * Closes the most recent sub-packet. It also writes out the length of the
201 * packet to the required location (normally the start of the WPACKET) if
202 * appropriate. The top level WPACKET should be closed using WPACKET_finish()
203 * instead of this function.
205 int WPACKET_close(WPACKET *pkt)
207 if (pkt->subs == NULL || pkt->subs->parent == NULL)
210 return wpacket_intern_close(pkt);
214 * The same as WPACKET_close() but only for the top most WPACKET. Additionally
215 * frees memory resources for this WPACKET.
217 int WPACKET_finish(WPACKET *pkt)
221 if (pkt->subs == NULL || pkt->subs->parent != NULL)
224 ret = wpacket_intern_close(pkt);
227 OPENSSL_free(pkt->subs);
234 * Initialise a new sub-packet. Additionally |lenbytes| of data is preallocated
235 * at the start of the sub-packet to store its length once we know it.
237 int WPACKET_start_sub_packet_len(WPACKET *pkt, size_t lenbytes)
241 if (pkt->subs == NULL)
244 sub = OPENSSL_zalloc(sizeof(*sub));
248 sub->parent = pkt->subs;
250 sub->pwritten = pkt->written + lenbytes;
251 sub->lenbytes = lenbytes;
254 sub->packet_len = NULL;
258 if (!WPACKET_allocate_bytes(pkt, lenbytes, &sub->packet_len)) {
266 * Same as WPACKET_get_sub_packet_len() except no bytes are pre-allocated for
267 * the sub-packet length.
269 int WPACKET_start_sub_packet(WPACKET *pkt)
271 return WPACKET_start_sub_packet_len(pkt, 0);
275 * Write the value stored in |val| into the WPACKET. The value will consome
276 * |bytes| amount of storage. An error will occur if |val| cannot be accommdated
277 * in |bytes| storage, e.g. attempting to write the value 256 into 1 byte will
280 int WPACKET_put_bytes(WPACKET *pkt, unsigned int val, size_t bytes)
284 if (bytes > sizeof(unsigned int)
285 || !WPACKET_allocate_bytes(pkt, bytes, &data))
289 for (; bytes > 0; bytes--) {
290 *data = (unsigned char)(val & 0xff);
295 /* Check whether we could fit the value in the assigned number of bytes */
302 /* Set a maximum size that we will not allow the WPACKET to grow beyond */
303 int WPACKET_set_max_size(WPACKET *pkt, size_t maxsize)
308 if (pkt->subs == NULL)
311 /* Find the WPACKET_SUB for the top level */
312 for (sub = pkt->subs; sub->parent != NULL; sub = sub->parent);
314 lenbytes = sub->lenbytes;
316 lenbytes = sizeof(pkt->maxsize);
318 if (maxmaxsize(lenbytes) < maxsize || maxsize < pkt->written)
321 pkt->maxsize = maxsize;
327 * Copy |len| bytes of data from |*src| into the WPACKET.
329 int WPACKET_memcpy(WPACKET *pkt, const void *src, size_t len)
336 if (!WPACKET_allocate_bytes(pkt, len, &dest))
339 memcpy(dest, src, len);
345 * Copy |len| bytes of data from |*src| into the WPACKET and prefix with its
346 * length (consuming |lenbytes| of data for the length)
348 int WPACKET_sub_memcpy(WPACKET *pkt, const void *src, size_t len, size_t lenbytes)
350 if (!WPACKET_start_sub_packet_len(pkt, lenbytes)
351 || !WPACKET_memcpy(pkt, src, len)
352 || !WPACKET_close(pkt))
359 * Return the total number of bytes written so far to the underlying buffer
360 * including any storage allocated for length bytes
362 int WPACKET_get_total_written(WPACKET *pkt, size_t *written)
367 *written = pkt->written;
373 * Returns the length of the last sub-packet. This excludes any bytes allocated
374 * for the length itself.
376 int WPACKET_get_length(WPACKET *pkt, size_t *len)
378 if (pkt->subs == NULL || len == NULL)
381 *len = pkt->written - pkt->subs->pwritten;
387 * Release resources in a WPACKET if a failure has occurred.
389 void WPACKET_cleanup(WPACKET *pkt)
391 WPACKET_SUB *sub, *parent;
393 for (sub = pkt->subs; sub != NULL; sub = parent) {
394 parent = sub->parent;