xref: /third_party/openssl/crypto/packet.c (revision e1051a39) 
1/*
2 * Copyright 2015-2022 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 "internal/packet.h"
12#include <openssl/err.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 \
39                     : ((p)->buf != NULL \
40                        ? (unsigned char *)(p)->buf->data \
41                        : NULL))
42
43int WPACKET_reserve_bytes(WPACKET *pkt, size_t len, unsigned char **allocbytes)
44{
45    /* Internal API, so should not fail */
46    if (!ossl_assert(pkt->subs != NULL && len != 0))
47        return 0;
48
49    if (pkt->maxsize - pkt->written < len)
50        return 0;
51
52    if (pkt->buf != NULL && (pkt->buf->length - pkt->written < len)) {
53        size_t newlen;
54        size_t reflen;
55
56        reflen = (len > pkt->buf->length) ? len : pkt->buf->length;
57
58        if (reflen > SIZE_MAX / 2) {
59            newlen = SIZE_MAX;
60        } else {
61            newlen = reflen * 2;
62            if (newlen < DEFAULT_BUF_SIZE)
63                newlen = DEFAULT_BUF_SIZE;
64        }
65        if (BUF_MEM_grow(pkt->buf, newlen) == 0)
66            return 0;
67    }
68    if (allocbytes != NULL) {
69        *allocbytes = WPACKET_get_curr(pkt);
70        if (pkt->endfirst && *allocbytes != NULL)
71            *allocbytes -= len;
72    }
73
74    return 1;
75}
76
77int WPACKET_sub_reserve_bytes__(WPACKET *pkt, size_t len,
78                                unsigned char **allocbytes, size_t lenbytes)
79{
80    if (pkt->endfirst && lenbytes > 0)
81        return 0;
82
83    if (!WPACKET_reserve_bytes(pkt, lenbytes + len, allocbytes))
84        return 0;
85
86    if (*allocbytes != NULL)
87        *allocbytes += lenbytes;
88
89    return 1;
90}
91
92static size_t maxmaxsize(size_t lenbytes)
93{
94    if (lenbytes >= sizeof(size_t) || lenbytes == 0)
95        return SIZE_MAX;
96
97    return ((size_t)1 << (lenbytes * 8)) - 1 + lenbytes;
98}
99
100static int wpacket_intern_init_len(WPACKET *pkt, size_t lenbytes)
101{
102    unsigned char *lenchars;
103
104    pkt->curr = 0;
105    pkt->written = 0;
106
107    if ((pkt->subs = OPENSSL_zalloc(sizeof(*pkt->subs))) == NULL) {
108        ERR_raise(ERR_LIB_CRYPTO, ERR_R_MALLOC_FAILURE);
109        return 0;
110    }
111
112    if (lenbytes == 0)
113        return 1;
114
115    pkt->subs->pwritten = lenbytes;
116    pkt->subs->lenbytes = lenbytes;
117
118    if (!WPACKET_allocate_bytes(pkt, lenbytes, &lenchars)) {
119        OPENSSL_free(pkt->subs);
120        pkt->subs = NULL;
121        return 0;
122    }
123    pkt->subs->packet_len = 0;
124
125    return 1;
126}
127
128int WPACKET_init_static_len(WPACKET *pkt, unsigned char *buf, size_t len,
129                            size_t lenbytes)
130{
131    size_t max = maxmaxsize(lenbytes);
132
133    /* Internal API, so should not fail */
134    if (!ossl_assert(buf != NULL && len > 0))
135        return 0;
136
137    pkt->staticbuf = buf;
138    pkt->buf = NULL;
139    pkt->maxsize = (max < len) ? max : len;
140    pkt->endfirst = 0;
141
142    return wpacket_intern_init_len(pkt, lenbytes);
143}
144
145int WPACKET_init_der(WPACKET *pkt, unsigned char *buf, size_t len)
146{
147    /* Internal API, so should not fail */
148    if (!ossl_assert(buf != NULL && len > 0))
149        return 0;
150
151    pkt->staticbuf = buf;
152    pkt->buf = NULL;
153    pkt->maxsize = len;
154    pkt->endfirst = 1;
155
156    return wpacket_intern_init_len(pkt, 0);
157}
158
159int WPACKET_init_len(WPACKET *pkt, BUF_MEM *buf, size_t lenbytes)
160{
161    /* Internal API, so should not fail */
162    if (!ossl_assert(buf != NULL))
163        return 0;
164
165    pkt->staticbuf = NULL;
166    pkt->buf = buf;
167    pkt->maxsize = maxmaxsize(lenbytes);
168    pkt->endfirst = 0;
169
170    return wpacket_intern_init_len(pkt, lenbytes);
171}
172
173int WPACKET_init(WPACKET *pkt, BUF_MEM *buf)
174{
175    return WPACKET_init_len(pkt, buf, 0);
176}
177
178int WPACKET_init_null(WPACKET *pkt, size_t lenbytes)
179{
180    pkt->staticbuf = NULL;
181    pkt->buf = NULL;
182    pkt->maxsize = maxmaxsize(lenbytes);
183    pkt->endfirst = 0;
184
185    return wpacket_intern_init_len(pkt, 0);
186}
187
188int WPACKET_init_null_der(WPACKET *pkt)
189{
190    pkt->staticbuf = NULL;
191    pkt->buf = NULL;
192    pkt->maxsize = SIZE_MAX;
193    pkt->endfirst = 1;
194
195    return wpacket_intern_init_len(pkt, 0);
196}
197
198int WPACKET_set_flags(WPACKET *pkt, unsigned int flags)
199{
200    /* Internal API, so should not fail */
201    if (!ossl_assert(pkt->subs != NULL))
202        return 0;
203
204    pkt->subs->flags = flags;
205
206    return 1;
207}
208
209/* Store the |value| of length |len| at location |data| */
210static int put_value(unsigned char *data, uint64_t value, size_t len)
211{
212    if (data == NULL)
213        return 1;
214
215    for (data += len - 1; len > 0; len--) {
216        *data = (unsigned char)(value & 0xff);
217        data--;
218        value >>= 8;
219    }
220
221    /* Check whether we could fit the value in the assigned number of bytes */
222    if (value > 0)
223        return 0;
224
225    return 1;
226}
227
228
229/*
230 * Internal helper function used by WPACKET_close(), WPACKET_finish() and
231 * WPACKET_fill_lengths() to close a sub-packet and write out its length if
232 * necessary. If |doclose| is 0 then it goes through the motions of closing
233 * (i.e. it fills in all the lengths), but doesn't actually close anything.
234 */
235static int wpacket_intern_close(WPACKET *pkt, WPACKET_SUB *sub, int doclose)
236{
237    size_t packlen = pkt->written - sub->pwritten;
238
239    if (packlen == 0
240            && (sub->flags & WPACKET_FLAGS_NON_ZERO_LENGTH) != 0)
241        return 0;
242
243    if (packlen == 0
244            && sub->flags & WPACKET_FLAGS_ABANDON_ON_ZERO_LENGTH) {
245        /* We can't handle this case. Return an error */
246        if (!doclose)
247            return 0;
248
249        /* Deallocate any bytes allocated for the length of the WPACKET */
250        if ((pkt->curr - sub->lenbytes) == sub->packet_len) {
251            pkt->written -= sub->lenbytes;
252            pkt->curr -= sub->lenbytes;
253        }
254
255        /* Don't write out the packet length */
256        sub->packet_len = 0;
257        sub->lenbytes = 0;
258    }
259
260    /* Write out the WPACKET length if needed */
261    if (sub->lenbytes > 0) {
262        unsigned char *buf = GETBUF(pkt);
263
264        if (buf != NULL
265                && !put_value(&buf[sub->packet_len], packlen,
266                              sub->lenbytes))
267            return 0;
268    } else if (pkt->endfirst && sub->parent != NULL
269               && (packlen != 0
270                   || (sub->flags
271                       & WPACKET_FLAGS_ABANDON_ON_ZERO_LENGTH) == 0)) {
272        size_t tmplen = packlen;
273        size_t numlenbytes = 1;
274
275        while ((tmplen = tmplen >> 8) > 0)
276            numlenbytes++;
277        if (!WPACKET_put_bytes__(pkt, packlen, numlenbytes))
278            return 0;
279        if (packlen > 0x7f) {
280            numlenbytes |= 0x80;
281            if (!WPACKET_put_bytes_u8(pkt, numlenbytes))
282                return 0;
283        }
284    }
285
286    if (doclose) {
287        pkt->subs = sub->parent;
288        OPENSSL_free(sub);
289    }
290
291    return 1;
292}
293
294int WPACKET_fill_lengths(WPACKET *pkt)
295{
296    WPACKET_SUB *sub;
297
298    if (!ossl_assert(pkt->subs != NULL))
299        return 0;
300
301    for (sub = pkt->subs; sub != NULL; sub = sub->parent) {
302        if (!wpacket_intern_close(pkt, sub, 0))
303            return 0;
304    }
305
306    return 1;
307}
308
309int WPACKET_close(WPACKET *pkt)
310{
311    /*
312     * Internal API, so should not fail - but we do negative testing of this
313     * so no assert (otherwise the tests fail)
314     */
315    if (pkt->subs == NULL || pkt->subs->parent == NULL)
316        return 0;
317
318    return wpacket_intern_close(pkt, pkt->subs, 1);
319}
320
321int WPACKET_finish(WPACKET *pkt)
322{
323    int ret;
324
325    /*
326     * Internal API, so should not fail - but we do negative testing of this
327     * so no assert (otherwise the tests fail)
328     */
329    if (pkt->subs == NULL || pkt->subs->parent != NULL)
330        return 0;
331
332    ret = wpacket_intern_close(pkt, pkt->subs, 1);
333    if (ret) {
334        OPENSSL_free(pkt->subs);
335        pkt->subs = NULL;
336    }
337
338    return ret;
339}
340
341int WPACKET_start_sub_packet_len__(WPACKET *pkt, size_t lenbytes)
342{
343    WPACKET_SUB *sub;
344    unsigned char *lenchars;
345
346    /* Internal API, so should not fail */
347    if (!ossl_assert(pkt->subs != NULL))
348        return 0;
349
350    /* We don't support lenbytes greater than 0 when doing endfirst writing */
351    if (lenbytes > 0 && pkt->endfirst)
352        return 0;
353
354    if ((sub = OPENSSL_zalloc(sizeof(*sub))) == NULL) {
355        ERR_raise(ERR_LIB_CRYPTO, ERR_R_MALLOC_FAILURE);
356        return 0;
357    }
358
359    sub->parent = pkt->subs;
360    pkt->subs = sub;
361    sub->pwritten = pkt->written + lenbytes;
362    sub->lenbytes = lenbytes;
363
364    if (lenbytes == 0) {
365        sub->packet_len = 0;
366        return 1;
367    }
368
369    sub->packet_len = pkt->written;
370
371    if (!WPACKET_allocate_bytes(pkt, lenbytes, &lenchars))
372        return 0;
373
374    return 1;
375}
376
377int WPACKET_start_sub_packet(WPACKET *pkt)
378{
379    return WPACKET_start_sub_packet_len__(pkt, 0);
380}
381
382int WPACKET_put_bytes__(WPACKET *pkt, uint64_t val, size_t size)
383{
384    unsigned char *data;
385
386    /* Internal API, so should not fail */
387    if (!ossl_assert(size <= sizeof(uint64_t))
388            || !WPACKET_allocate_bytes(pkt, size, &data)
389            || !put_value(data, val, size))
390        return 0;
391
392    return 1;
393}
394
395int WPACKET_set_max_size(WPACKET *pkt, size_t maxsize)
396{
397    WPACKET_SUB *sub;
398    size_t lenbytes;
399
400    /* Internal API, so should not fail */
401    if (!ossl_assert(pkt->subs != NULL))
402        return 0;
403
404    /* Find the WPACKET_SUB for the top level */
405    for (sub = pkt->subs; sub->parent != NULL; sub = sub->parent)
406        continue;
407
408    lenbytes = sub->lenbytes;
409    if (lenbytes == 0)
410        lenbytes = sizeof(pkt->maxsize);
411
412    if (maxmaxsize(lenbytes) < maxsize || maxsize < pkt->written)
413        return 0;
414
415    pkt->maxsize = maxsize;
416
417    return 1;
418}
419
420int WPACKET_memset(WPACKET *pkt, int ch, size_t len)
421{
422    unsigned char *dest;
423
424    if (len == 0)
425        return 1;
426
427    if (!WPACKET_allocate_bytes(pkt, len, &dest))
428        return 0;
429
430    if (dest != NULL)
431        memset(dest, ch, len);
432
433    return 1;
434}
435
436int WPACKET_memcpy(WPACKET *pkt, const void *src, size_t len)
437{
438    unsigned char *dest;
439
440    if (len == 0)
441        return 1;
442
443    if (!WPACKET_allocate_bytes(pkt, len, &dest))
444        return 0;
445
446    if (dest != NULL)
447        memcpy(dest, src, len);
448
449    return 1;
450}
451
452int WPACKET_sub_memcpy__(WPACKET *pkt, const void *src, size_t len,
453                         size_t lenbytes)
454{
455    if (!WPACKET_start_sub_packet_len__(pkt, lenbytes)
456            || !WPACKET_memcpy(pkt, src, len)
457            || !WPACKET_close(pkt))
458        return 0;
459
460    return 1;
461}
462
463int WPACKET_get_total_written(WPACKET *pkt, size_t *written)
464{
465    /* Internal API, so should not fail */
466    if (!ossl_assert(written != NULL))
467        return 0;
468
469    *written = pkt->written;
470
471    return 1;
472}
473
474int WPACKET_get_length(WPACKET *pkt, size_t *len)
475{
476    /* Internal API, so should not fail */
477    if (!ossl_assert(pkt->subs != NULL && len != NULL))
478        return 0;
479
480    *len = pkt->written - pkt->subs->pwritten;
481
482    return 1;
483}
484
485unsigned char *WPACKET_get_curr(WPACKET *pkt)
486{
487    unsigned char *buf = GETBUF(pkt);
488
489    if (buf == NULL)
490        return NULL;
491
492    if (pkt->endfirst)
493        return buf + pkt->maxsize - pkt->curr;
494
495    return buf + pkt->curr;
496}
497
498int WPACKET_is_null_buf(WPACKET *pkt)
499{
500    return pkt->buf == NULL && pkt->staticbuf == NULL;
501}
502
503void WPACKET_cleanup(WPACKET *pkt)
504{
505    WPACKET_SUB *sub, *parent;
506
507    for (sub = pkt->subs; sub != NULL; sub = parent) {
508        parent = sub->parent;
509        OPENSSL_free(sub);
510    }
511    pkt->subs = NULL;
512}
513