1/*
2 * Copyright 2015-2018 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 "internal/cryptlib.h"
11#include "packet_local.h"
12#include <openssl/sslerr.h>
13
14#define DEFAULT_BUF_SIZE    256
15
16int 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
26int 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
40int 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
71int 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
82static 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
90static 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
118int 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
134int 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
147int WPACKET_init(WPACKET *pkt, BUF_MEM *buf)
148{
149    return WPACKET_init_len(pkt, buf, 0);
150}
151
152int 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| */
164static 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 */
186static 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
225int 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
240int 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
252int 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
272int 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
304int WPACKET_start_sub_packet(WPACKET *pkt)
305{
306    return WPACKET_start_sub_packet_len__(pkt, 0);
307}
308
309int 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
322int 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
347int 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
362int 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
377int 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
388int 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
399int 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
410unsigned char *WPACKET_get_curr(WPACKET *pkt)
411{
412    return GETBUF(pkt) + pkt->curr;
413}
414
415void 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}
425