xref: /netbsd-src/crypto/external/bsd/openssl.old/dist/ssl/packet_local.h (revision 4724848cf0da353df257f730694b7882798e5daf)
1 /*
2  * Copyright 2015-2022 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 #ifndef OSSL_SSL_PACKET_LOCAL_H
11 # define OSSL_SSL_PACKET_LOCAL_H
12 
13 # include <string.h>
14 # include <openssl/bn.h>
15 # include <openssl/buffer.h>
16 # include <openssl/crypto.h>
17 # include <openssl/e_os2.h>
18 
19 # include "internal/numbers.h"
20 
21 typedef struct {
22     /* Pointer to where we are currently reading from */
23     const unsigned char *curr;
24     /* Number of bytes remaining */
25     size_t remaining;
26 } PACKET;
27 
28 /* Internal unchecked shorthand; don't use outside this file. */
packet_forward(PACKET * pkt,size_t len)29 static ossl_inline void packet_forward(PACKET *pkt, size_t len)
30 {
31     pkt->curr += len;
32     pkt->remaining -= len;
33 }
34 
35 /*
36  * Returns the number of bytes remaining to be read in the PACKET
37  */
PACKET_remaining(const PACKET * pkt)38 static ossl_inline size_t PACKET_remaining(const PACKET *pkt)
39 {
40     return pkt->remaining;
41 }
42 
43 /*
44  * Returns a pointer to the first byte after the packet data.
45  * Useful for integrating with non-PACKET parsing code.
46  * Specifically, we use PACKET_end() to verify that a d2i_... call
47  * has consumed the entire packet contents.
48  */
PACKET_end(const PACKET * pkt)49 static ossl_inline const unsigned char *PACKET_end(const PACKET *pkt)
50 {
51     return pkt->curr + pkt->remaining;
52 }
53 
54 /*
55  * Returns a pointer to the PACKET's current position.
56  * For use in non-PACKETized APIs.
57  */
PACKET_data(const PACKET * pkt)58 static ossl_inline const unsigned char *PACKET_data(const PACKET *pkt)
59 {
60     return pkt->curr;
61 }
62 
63 /*
64  * Initialise a PACKET with |len| bytes held in |buf|. This does not make a
65  * copy of the data so |buf| must be present for the whole time that the PACKET
66  * is being used.
67  */
PACKET_buf_init(PACKET * pkt,const unsigned char * buf,size_t len)68 __owur static ossl_inline int PACKET_buf_init(PACKET *pkt,
69                                               const unsigned char *buf,
70                                               size_t len)
71 {
72     /* Sanity check for negative values. */
73     if (len > (size_t)(SIZE_MAX / 2))
74         return 0;
75 
76     pkt->curr = buf;
77     pkt->remaining = len;
78     return 1;
79 }
80 
81 /* Initialize a PACKET to hold zero bytes. */
PACKET_null_init(PACKET * pkt)82 static ossl_inline void PACKET_null_init(PACKET *pkt)
83 {
84     pkt->curr = NULL;
85     pkt->remaining = 0;
86 }
87 
88 /*
89  * Returns 1 if the packet has length |num| and its contents equal the |num|
90  * bytes read from |ptr|. Returns 0 otherwise (lengths or contents not equal).
91  * If lengths are equal, performs the comparison in constant time.
92  */
PACKET_equal(const PACKET * pkt,const void * ptr,size_t num)93 __owur static ossl_inline int PACKET_equal(const PACKET *pkt, const void *ptr,
94                                            size_t num)
95 {
96     if (PACKET_remaining(pkt) != num)
97         return 0;
98     return CRYPTO_memcmp(pkt->curr, ptr, num) == 0;
99 }
100 
101 /*
102  * Peek ahead and initialize |subpkt| with the next |len| bytes read from |pkt|.
103  * Data is not copied: the |subpkt| packet will share its underlying buffer with
104  * the original |pkt|, so data wrapped by |pkt| must outlive the |subpkt|.
105  */
PACKET_peek_sub_packet(const PACKET * pkt,PACKET * subpkt,size_t len)106 __owur static ossl_inline int PACKET_peek_sub_packet(const PACKET *pkt,
107                                                      PACKET *subpkt, size_t len)
108 {
109     if (PACKET_remaining(pkt) < len)
110         return 0;
111 
112     return PACKET_buf_init(subpkt, pkt->curr, len);
113 }
114 
115 /*
116  * Initialize |subpkt| with the next |len| bytes read from |pkt|. Data is not
117  * copied: the |subpkt| packet will share its underlying buffer with the
118  * original |pkt|, so data wrapped by |pkt| must outlive the |subpkt|.
119  */
PACKET_get_sub_packet(PACKET * pkt,PACKET * subpkt,size_t len)120 __owur static ossl_inline int PACKET_get_sub_packet(PACKET *pkt,
121                                                     PACKET *subpkt, size_t len)
122 {
123     if (!PACKET_peek_sub_packet(pkt, subpkt, len))
124         return 0;
125 
126     packet_forward(pkt, len);
127 
128     return 1;
129 }
130 
131 /*
132  * Peek ahead at 2 bytes in network order from |pkt| and store the value in
133  * |*data|
134  */
PACKET_peek_net_2(const PACKET * pkt,unsigned int * data)135 __owur static ossl_inline int PACKET_peek_net_2(const PACKET *pkt,
136                                                 unsigned int *data)
137 {
138     if (PACKET_remaining(pkt) < 2)
139         return 0;
140 
141     *data = ((unsigned int)(*pkt->curr)) << 8;
142     *data |= *(pkt->curr + 1);
143 
144     return 1;
145 }
146 
147 /* Equivalent of n2s */
148 /* Get 2 bytes in network order from |pkt| and store the value in |*data| */
PACKET_get_net_2(PACKET * pkt,unsigned int * data)149 __owur static ossl_inline int PACKET_get_net_2(PACKET *pkt, unsigned int *data)
150 {
151     if (!PACKET_peek_net_2(pkt, data))
152         return 0;
153 
154     packet_forward(pkt, 2);
155 
156     return 1;
157 }
158 
159 /* Same as PACKET_get_net_2() but for a size_t */
PACKET_get_net_2_len(PACKET * pkt,size_t * data)160 __owur static ossl_inline int PACKET_get_net_2_len(PACKET *pkt, size_t *data)
161 {
162     unsigned int i;
163     int ret = PACKET_get_net_2(pkt, &i);
164 
165     if (ret)
166         *data = (size_t)i;
167 
168     return ret;
169 }
170 
171 /*
172  * Peek ahead at 3 bytes in network order from |pkt| and store the value in
173  * |*data|
174  */
PACKET_peek_net_3(const PACKET * pkt,unsigned long * data)175 __owur static ossl_inline int PACKET_peek_net_3(const PACKET *pkt,
176                                                 unsigned long *data)
177 {
178     if (PACKET_remaining(pkt) < 3)
179         return 0;
180 
181     *data = ((unsigned long)(*pkt->curr)) << 16;
182     *data |= ((unsigned long)(*(pkt->curr + 1))) << 8;
183     *data |= *(pkt->curr + 2);
184 
185     return 1;
186 }
187 
188 /* Equivalent of n2l3 */
189 /* Get 3 bytes in network order from |pkt| and store the value in |*data| */
PACKET_get_net_3(PACKET * pkt,unsigned long * data)190 __owur static ossl_inline int PACKET_get_net_3(PACKET *pkt, unsigned long *data)
191 {
192     if (!PACKET_peek_net_3(pkt, data))
193         return 0;
194 
195     packet_forward(pkt, 3);
196 
197     return 1;
198 }
199 
200 /* Same as PACKET_get_net_3() but for a size_t */
PACKET_get_net_3_len(PACKET * pkt,size_t * data)201 __owur static ossl_inline int PACKET_get_net_3_len(PACKET *pkt, size_t *data)
202 {
203     unsigned long i;
204     int ret = PACKET_get_net_3(pkt, &i);
205 
206     if (ret)
207         *data = (size_t)i;
208 
209     return ret;
210 }
211 
212 /*
213  * Peek ahead at 4 bytes in network order from |pkt| and store the value in
214  * |*data|
215  */
PACKET_peek_net_4(const PACKET * pkt,unsigned long * data)216 __owur static ossl_inline int PACKET_peek_net_4(const PACKET *pkt,
217                                                 unsigned long *data)
218 {
219     if (PACKET_remaining(pkt) < 4)
220         return 0;
221 
222     *data = ((unsigned long)(*pkt->curr)) << 24;
223     *data |= ((unsigned long)(*(pkt->curr + 1))) << 16;
224     *data |= ((unsigned long)(*(pkt->curr + 2))) << 8;
225     *data |= *(pkt->curr + 3);
226 
227     return 1;
228 }
229 
230 /*
231  * Peek ahead at 8 bytes in network order from |pkt| and store the value in
232  * |*data|
233  */
PACKET_peek_net_8(const PACKET * pkt,uint64_t * data)234 __owur static ossl_inline int PACKET_peek_net_8(const PACKET *pkt,
235                                                 uint64_t *data)
236 {
237     if (PACKET_remaining(pkt) < 8)
238         return 0;
239 
240     *data = ((uint64_t)(*pkt->curr)) << 56;
241     *data |= ((uint64_t)(*(pkt->curr + 1))) << 48;
242     *data |= ((uint64_t)(*(pkt->curr + 2))) << 40;
243     *data |= ((uint64_t)(*(pkt->curr + 3))) << 32;
244     *data |= ((uint64_t)(*(pkt->curr + 4))) << 24;
245     *data |= ((uint64_t)(*(pkt->curr + 5))) << 16;
246     *data |= ((uint64_t)(*(pkt->curr + 6))) << 8;
247     *data |= *(pkt->curr + 7);
248 
249     return 1;
250 }
251 
252 /* Equivalent of n2l */
253 /* Get 4 bytes in network order from |pkt| and store the value in |*data| */
PACKET_get_net_4(PACKET * pkt,unsigned long * data)254 __owur static ossl_inline int PACKET_get_net_4(PACKET *pkt, unsigned long *data)
255 {
256     if (!PACKET_peek_net_4(pkt, data))
257         return 0;
258 
259     packet_forward(pkt, 4);
260 
261     return 1;
262 }
263 
264 /* Same as PACKET_get_net_4() but for a size_t */
PACKET_get_net_4_len(PACKET * pkt,size_t * data)265 __owur static ossl_inline int PACKET_get_net_4_len(PACKET *pkt, size_t *data)
266 {
267     unsigned long i;
268     int ret = PACKET_get_net_4(pkt, &i);
269 
270     if (ret)
271         *data = (size_t)i;
272 
273     return ret;
274 }
275 
276 /* Get 8 bytes in network order from |pkt| and store the value in |*data| */
PACKET_get_net_8(PACKET * pkt,uint64_t * data)277 __owur static ossl_inline int PACKET_get_net_8(PACKET *pkt, uint64_t *data)
278 {
279     if (!PACKET_peek_net_8(pkt, data))
280         return 0;
281 
282     packet_forward(pkt, 8);
283 
284     return 1;
285 }
286 
287 /* Peek ahead at 1 byte from |pkt| and store the value in |*data| */
PACKET_peek_1(const PACKET * pkt,unsigned int * data)288 __owur static ossl_inline int PACKET_peek_1(const PACKET *pkt,
289                                             unsigned int *data)
290 {
291     if (!PACKET_remaining(pkt))
292         return 0;
293 
294     *data = *pkt->curr;
295 
296     return 1;
297 }
298 
299 /* Get 1 byte from |pkt| and store the value in |*data| */
PACKET_get_1(PACKET * pkt,unsigned int * data)300 __owur static ossl_inline int PACKET_get_1(PACKET *pkt, unsigned int *data)
301 {
302     if (!PACKET_peek_1(pkt, data))
303         return 0;
304 
305     packet_forward(pkt, 1);
306 
307     return 1;
308 }
309 
310 /* Same as PACKET_get_1() but for a size_t */
PACKET_get_1_len(PACKET * pkt,size_t * data)311 __owur static ossl_inline int PACKET_get_1_len(PACKET *pkt, size_t *data)
312 {
313     unsigned int i;
314     int ret = PACKET_get_1(pkt, &i);
315 
316     if (ret)
317         *data = (size_t)i;
318 
319     return ret;
320 }
321 
322 /*
323  * Peek ahead at 4 bytes in reverse network order from |pkt| and store the value
324  * in |*data|
325  */
PACKET_peek_4(const PACKET * pkt,unsigned long * data)326 __owur static ossl_inline int PACKET_peek_4(const PACKET *pkt,
327                                             unsigned long *data)
328 {
329     if (PACKET_remaining(pkt) < 4)
330         return 0;
331 
332     *data = *pkt->curr;
333     *data |= ((unsigned long)(*(pkt->curr + 1))) << 8;
334     *data |= ((unsigned long)(*(pkt->curr + 2))) << 16;
335     *data |= ((unsigned long)(*(pkt->curr + 3))) << 24;
336 
337     return 1;
338 }
339 
340 /* Equivalent of c2l */
341 /*
342  * Get 4 bytes in reverse network order from |pkt| and store the value in
343  * |*data|
344  */
PACKET_get_4(PACKET * pkt,unsigned long * data)345 __owur static ossl_inline int PACKET_get_4(PACKET *pkt, unsigned long *data)
346 {
347     if (!PACKET_peek_4(pkt, data))
348         return 0;
349 
350     packet_forward(pkt, 4);
351 
352     return 1;
353 }
354 
355 /*
356  * Peek ahead at |len| bytes from the |pkt| and store a pointer to them in
357  * |*data|. This just points at the underlying buffer that |pkt| is using. The
358  * caller should not free this data directly (it will be freed when the
359  * underlying buffer gets freed
360  */
PACKET_peek_bytes(const PACKET * pkt,const unsigned char ** data,size_t len)361 __owur static ossl_inline int PACKET_peek_bytes(const PACKET *pkt,
362                                                 const unsigned char **data,
363                                                 size_t len)
364 {
365     if (PACKET_remaining(pkt) < len)
366         return 0;
367 
368     *data = pkt->curr;
369 
370     return 1;
371 }
372 
373 /*
374  * Read |len| bytes from the |pkt| and store a pointer to them in |*data|. This
375  * just points at the underlying buffer that |pkt| is using. The caller should
376  * not free this data directly (it will be freed when the underlying buffer gets
377  * freed
378  */
PACKET_get_bytes(PACKET * pkt,const unsigned char ** data,size_t len)379 __owur static ossl_inline int PACKET_get_bytes(PACKET *pkt,
380                                                const unsigned char **data,
381                                                size_t len)
382 {
383     if (!PACKET_peek_bytes(pkt, data, len))
384         return 0;
385 
386     packet_forward(pkt, len);
387 
388     return 1;
389 }
390 
391 /* Peek ahead at |len| bytes from |pkt| and copy them to |data| */
PACKET_peek_copy_bytes(const PACKET * pkt,unsigned char * data,size_t len)392 __owur static ossl_inline int PACKET_peek_copy_bytes(const PACKET *pkt,
393                                                      unsigned char *data,
394                                                      size_t len)
395 {
396     if (PACKET_remaining(pkt) < len)
397         return 0;
398 
399     memcpy(data, pkt->curr, len);
400 
401     return 1;
402 }
403 
404 /*
405  * Read |len| bytes from |pkt| and copy them to |data|.
406  * The caller is responsible for ensuring that |data| can hold |len| bytes.
407  */
PACKET_copy_bytes(PACKET * pkt,unsigned char * data,size_t len)408 __owur static ossl_inline int PACKET_copy_bytes(PACKET *pkt,
409                                                 unsigned char *data, size_t len)
410 {
411     if (!PACKET_peek_copy_bytes(pkt, data, len))
412         return 0;
413 
414     packet_forward(pkt, len);
415 
416     return 1;
417 }
418 
419 /*
420  * Copy packet data to |dest|, and set |len| to the number of copied bytes.
421  * If the packet has more than |dest_len| bytes, nothing is copied.
422  * Returns 1 if the packet data fits in |dest_len| bytes, 0 otherwise.
423  * Does not forward PACKET position (because it is typically the last thing
424  * done with a given PACKET).
425  */
PACKET_copy_all(const PACKET * pkt,unsigned char * dest,size_t dest_len,size_t * len)426 __owur static ossl_inline int PACKET_copy_all(const PACKET *pkt,
427                                               unsigned char *dest,
428                                               size_t dest_len, size_t *len)
429 {
430     if (PACKET_remaining(pkt) > dest_len) {
431         *len = 0;
432         return 0;
433     }
434     *len = pkt->remaining;
435     memcpy(dest, pkt->curr, pkt->remaining);
436     return 1;
437 }
438 
439 /*
440  * Copy |pkt| bytes to a newly allocated buffer and store a pointer to the
441  * result in |*data|, and the length in |len|.
442  * If |*data| is not NULL, the old data is OPENSSL_free'd.
443  * If the packet is empty, or malloc fails, |*data| will be set to NULL.
444  * Returns 1 if the malloc succeeds and 0 otherwise.
445  * Does not forward PACKET position (because it is typically the last thing
446  * done with a given PACKET).
447  */
PACKET_memdup(const PACKET * pkt,unsigned char ** data,size_t * len)448 __owur static ossl_inline int PACKET_memdup(const PACKET *pkt,
449                                             unsigned char **data, size_t *len)
450 {
451     size_t length;
452 
453     OPENSSL_free(*data);
454     *data = NULL;
455     *len = 0;
456 
457     length = PACKET_remaining(pkt);
458 
459     if (length == 0)
460         return 1;
461 
462     *data = OPENSSL_memdup(pkt->curr, length);
463     if (*data == NULL)
464         return 0;
465 
466     *len = length;
467     return 1;
468 }
469 
470 /*
471  * Read a C string from |pkt| and copy to a newly allocated, NUL-terminated
472  * buffer. Store a pointer to the result in |*data|.
473  * If |*data| is not NULL, the old data is OPENSSL_free'd.
474  * If the data in |pkt| does not contain a NUL-byte, the entire data is
475  * copied and NUL-terminated.
476  * Returns 1 if the malloc succeeds and 0 otherwise.
477  * Does not forward PACKET position (because it is typically the last thing done
478  * with a given PACKET).
479  */
PACKET_strndup(const PACKET * pkt,char ** data)480 __owur static ossl_inline int PACKET_strndup(const PACKET *pkt, char **data)
481 {
482     OPENSSL_free(*data);
483 
484     /* This will succeed on an empty packet, unless pkt->curr == NULL. */
485     *data = OPENSSL_strndup((const char *)pkt->curr, PACKET_remaining(pkt));
486     return (*data != NULL);
487 }
488 
489 /* Returns 1 if |pkt| contains at least one 0-byte, 0 otherwise. */
PACKET_contains_zero_byte(const PACKET * pkt)490 static ossl_inline int PACKET_contains_zero_byte(const PACKET *pkt)
491 {
492     return memchr(pkt->curr, 0, pkt->remaining) != NULL;
493 }
494 
495 /* Move the current reading position forward |len| bytes */
PACKET_forward(PACKET * pkt,size_t len)496 __owur static ossl_inline int PACKET_forward(PACKET *pkt, size_t len)
497 {
498     if (PACKET_remaining(pkt) < len)
499         return 0;
500 
501     packet_forward(pkt, len);
502 
503     return 1;
504 }
505 
506 /*
507  * Reads a variable-length vector prefixed with a one-byte length, and stores
508  * the contents in |subpkt|. |pkt| can equal |subpkt|.
509  * Data is not copied: the |subpkt| packet will share its underlying buffer with
510  * the original |pkt|, so data wrapped by |pkt| must outlive the |subpkt|.
511  * Upon failure, the original |pkt| and |subpkt| are not modified.
512  */
PACKET_get_length_prefixed_1(PACKET * pkt,PACKET * subpkt)513 __owur static ossl_inline int PACKET_get_length_prefixed_1(PACKET *pkt,
514                                                            PACKET *subpkt)
515 {
516     unsigned int length;
517     const unsigned char *data;
518     PACKET tmp = *pkt;
519     if (!PACKET_get_1(&tmp, &length) ||
520         !PACKET_get_bytes(&tmp, &data, (size_t)length)) {
521         return 0;
522     }
523 
524     *pkt = tmp;
525     subpkt->curr = data;
526     subpkt->remaining = length;
527 
528     return 1;
529 }
530 
531 /*
532  * Like PACKET_get_length_prefixed_1, but additionally, fails when there are
533  * leftover bytes in |pkt|.
534  */
PACKET_as_length_prefixed_1(PACKET * pkt,PACKET * subpkt)535 __owur static ossl_inline int PACKET_as_length_prefixed_1(PACKET *pkt,
536                                                           PACKET *subpkt)
537 {
538     unsigned int length;
539     const unsigned char *data;
540     PACKET tmp = *pkt;
541     if (!PACKET_get_1(&tmp, &length) ||
542         !PACKET_get_bytes(&tmp, &data, (size_t)length) ||
543         PACKET_remaining(&tmp) != 0) {
544         return 0;
545     }
546 
547     *pkt = tmp;
548     subpkt->curr = data;
549     subpkt->remaining = length;
550 
551     return 1;
552 }
553 
554 /*
555  * Reads a variable-length vector prefixed with a two-byte length, and stores
556  * the contents in |subpkt|. |pkt| can equal |subpkt|.
557  * Data is not copied: the |subpkt| packet will share its underlying buffer with
558  * the original |pkt|, so data wrapped by |pkt| must outlive the |subpkt|.
559  * Upon failure, the original |pkt| and |subpkt| are not modified.
560  */
PACKET_get_length_prefixed_2(PACKET * pkt,PACKET * subpkt)561 __owur static ossl_inline int PACKET_get_length_prefixed_2(PACKET *pkt,
562                                                            PACKET *subpkt)
563 {
564     unsigned int length;
565     const unsigned char *data;
566     PACKET tmp = *pkt;
567 
568     if (!PACKET_get_net_2(&tmp, &length) ||
569         !PACKET_get_bytes(&tmp, &data, (size_t)length)) {
570         return 0;
571     }
572 
573     *pkt = tmp;
574     subpkt->curr = data;
575     subpkt->remaining = length;
576 
577     return 1;
578 }
579 
580 /*
581  * Like PACKET_get_length_prefixed_2, but additionally, fails when there are
582  * leftover bytes in |pkt|.
583  */
PACKET_as_length_prefixed_2(PACKET * pkt,PACKET * subpkt)584 __owur static ossl_inline int PACKET_as_length_prefixed_2(PACKET *pkt,
585                                                           PACKET *subpkt)
586 {
587     unsigned int length;
588     const unsigned char *data;
589     PACKET tmp = *pkt;
590 
591     if (!PACKET_get_net_2(&tmp, &length) ||
592         !PACKET_get_bytes(&tmp, &data, (size_t)length) ||
593         PACKET_remaining(&tmp) != 0) {
594         return 0;
595     }
596 
597     *pkt = tmp;
598     subpkt->curr = data;
599     subpkt->remaining = length;
600 
601     return 1;
602 }
603 
604 /*
605  * Reads a variable-length vector prefixed with a three-byte length, and stores
606  * the contents in |subpkt|. |pkt| can equal |subpkt|.
607  * Data is not copied: the |subpkt| packet will share its underlying buffer with
608  * the original |pkt|, so data wrapped by |pkt| must outlive the |subpkt|.
609  * Upon failure, the original |pkt| and |subpkt| are not modified.
610  */
PACKET_get_length_prefixed_3(PACKET * pkt,PACKET * subpkt)611 __owur static ossl_inline int PACKET_get_length_prefixed_3(PACKET *pkt,
612                                                            PACKET *subpkt)
613 {
614     unsigned long length;
615     const unsigned char *data;
616     PACKET tmp = *pkt;
617     if (!PACKET_get_net_3(&tmp, &length) ||
618         !PACKET_get_bytes(&tmp, &data, (size_t)length)) {
619         return 0;
620     }
621 
622     *pkt = tmp;
623     subpkt->curr = data;
624     subpkt->remaining = length;
625 
626     return 1;
627 }
628 
629 /* Writeable packets */
630 
631 typedef struct wpacket_sub WPACKET_SUB;
632 struct wpacket_sub {
633     /* The parent WPACKET_SUB if we have one or NULL otherwise */
634     WPACKET_SUB *parent;
635 
636     /*
637      * Offset into the buffer where the length of this WPACKET goes. We use an
638      * offset in case the buffer grows and gets reallocated.
639      */
640     size_t packet_len;
641 
642     /* Number of bytes in the packet_len or 0 if we don't write the length */
643     size_t lenbytes;
644 
645     /* Number of bytes written to the buf prior to this packet starting */
646     size_t pwritten;
647 
648     /* Flags for this sub-packet */
649     unsigned int flags;
650 };
651 
652 typedef struct wpacket_st WPACKET;
653 struct wpacket_st {
654     /* The buffer where we store the output data */
655     BUF_MEM *buf;
656 
657     /* Fixed sized buffer which can be used as an alternative to buf */
658     unsigned char *staticbuf;
659 
660     /*
661      * Offset into the buffer where we are currently writing. We use an offset
662      * in case the buffer grows and gets reallocated.
663      */
664     size_t curr;
665 
666     /* Number of bytes written so far */
667     size_t written;
668 
669     /* Maximum number of bytes we will allow to be written to this WPACKET */
670     size_t maxsize;
671 
672     /* Our sub-packets (always at least one if not finished) */
673     WPACKET_SUB *subs;
674 };
675 
676 /* Flags */
677 
678 /* Default */
679 #define WPACKET_FLAGS_NONE                      0
680 
681 /* Error on WPACKET_close() if no data written to the WPACKET */
682 #define WPACKET_FLAGS_NON_ZERO_LENGTH           1
683 
684 /*
685  * Abandon all changes on WPACKET_close() if no data written to the WPACKET,
686  * i.e. this does not write out a zero packet length
687  */
688 #define WPACKET_FLAGS_ABANDON_ON_ZERO_LENGTH    2
689 
690 
691 /*
692  * Initialise a WPACKET with the buffer in |buf|. The buffer must exist
693  * for the whole time that the WPACKET is being used. Additionally |lenbytes| of
694  * data is preallocated at the start of the buffer to store the length of the
695  * WPACKET once we know it.
696  */
697 int WPACKET_init_len(WPACKET *pkt, BUF_MEM *buf, size_t lenbytes);
698 
699 /*
700  * Same as WPACKET_init_len except there is no preallocation of the WPACKET
701  * length.
702  */
703 int WPACKET_init(WPACKET *pkt, BUF_MEM *buf);
704 
705 /*
706  * Same as WPACKET_init_len except we do not use a growable BUF_MEM structure.
707  * A fixed buffer of memory |buf| of size |len| is used instead. A failure will
708  * occur if you attempt to write beyond the end of the buffer
709  */
710 int WPACKET_init_static_len(WPACKET *pkt, unsigned char *buf, size_t len,
711                             size_t lenbytes);
712 /*
713  * Set the flags to be applied to the current sub-packet
714  */
715 int WPACKET_set_flags(WPACKET *pkt, unsigned int flags);
716 
717 /*
718  * Closes the most recent sub-packet. It also writes out the length of the
719  * packet to the required location (normally the start of the WPACKET) if
720  * appropriate. The top level WPACKET should be closed using WPACKET_finish()
721  * instead of this function.
722  */
723 int WPACKET_close(WPACKET *pkt);
724 
725 /*
726  * The same as WPACKET_close() but only for the top most WPACKET. Additionally
727  * frees memory resources for this WPACKET.
728  */
729 int WPACKET_finish(WPACKET *pkt);
730 
731 /*
732  * Iterate through all the sub-packets and write out their lengths as if they
733  * were being closed. The lengths will be overwritten with the final lengths
734  * when the sub-packets are eventually closed (which may be different if more
735  * data is added to the WPACKET). This function fails if a sub-packet is of 0
736  * length and WPACKET_FLAGS_ABANDON_ON_ZERO_LENGTH is set.
737  */
738 int WPACKET_fill_lengths(WPACKET *pkt);
739 
740 /*
741  * Initialise a new sub-packet. Additionally |lenbytes| of data is preallocated
742  * at the start of the sub-packet to store its length once we know it. Don't
743  * call this directly. Use the convenience macros below instead.
744  */
745 int WPACKET_start_sub_packet_len__(WPACKET *pkt, size_t lenbytes);
746 
747 /*
748  * Convenience macros for calling WPACKET_start_sub_packet_len with different
749  * lengths
750  */
751 #define WPACKET_start_sub_packet_u8(pkt) \
752     WPACKET_start_sub_packet_len__((pkt), 1)
753 #define WPACKET_start_sub_packet_u16(pkt) \
754     WPACKET_start_sub_packet_len__((pkt), 2)
755 #define WPACKET_start_sub_packet_u24(pkt) \
756     WPACKET_start_sub_packet_len__((pkt), 3)
757 #define WPACKET_start_sub_packet_u32(pkt) \
758     WPACKET_start_sub_packet_len__((pkt), 4)
759 
760 /*
761  * Same as WPACKET_start_sub_packet_len__() except no bytes are pre-allocated
762  * for the sub-packet length.
763  */
764 int WPACKET_start_sub_packet(WPACKET *pkt);
765 
766 /*
767  * Allocate bytes in the WPACKET for the output. This reserves the bytes
768  * and counts them as "written", but doesn't actually do the writing. A pointer
769  * to the allocated bytes is stored in |*allocbytes|. |allocbytes| may be NULL.
770  * WARNING: the allocated bytes must be filled in immediately, without further
771  * WPACKET_* calls. If not then the underlying buffer may be realloc'd and
772  * change its location.
773  */
774 int WPACKET_allocate_bytes(WPACKET *pkt, size_t len,
775                            unsigned char **allocbytes);
776 
777 /*
778  * The same as WPACKET_allocate_bytes() except additionally a new sub-packet is
779  * started for the allocated bytes, and then closed immediately afterwards. The
780  * number of length bytes for the sub-packet is in |lenbytes|. Don't call this
781  * directly. Use the convenience macros below instead.
782  */
783 int WPACKET_sub_allocate_bytes__(WPACKET *pkt, size_t len,
784                                  unsigned char **allocbytes, size_t lenbytes);
785 
786 /*
787  * Convenience macros for calling WPACKET_sub_allocate_bytes with different
788  * lengths
789  */
790 #define WPACKET_sub_allocate_bytes_u8(pkt, len, bytes) \
791     WPACKET_sub_allocate_bytes__((pkt), (len), (bytes), 1)
792 #define WPACKET_sub_allocate_bytes_u16(pkt, len, bytes) \
793     WPACKET_sub_allocate_bytes__((pkt), (len), (bytes), 2)
794 #define WPACKET_sub_allocate_bytes_u24(pkt, len, bytes) \
795     WPACKET_sub_allocate_bytes__((pkt), (len), (bytes), 3)
796 #define WPACKET_sub_allocate_bytes_u32(pkt, len, bytes) \
797     WPACKET_sub_allocate_bytes__((pkt), (len), (bytes), 4)
798 
799 /*
800  * The same as WPACKET_allocate_bytes() except the reserved bytes are not
801  * actually counted as written. Typically this will be for when we don't know
802  * how big arbitrary data is going to be up front, but we do know what the
803  * maximum size will be. If this function is used, then it should be immediately
804  * followed by a WPACKET_allocate_bytes() call before any other WPACKET
805  * functions are called (unless the write to the allocated bytes is abandoned).
806  *
807  * For example: If we are generating a signature, then the size of that
808  * signature may not be known in advance. We can use WPACKET_reserve_bytes() to
809  * handle this:
810  *
811  *  if (!WPACKET_sub_reserve_bytes_u16(&pkt, EVP_PKEY_size(pkey), &sigbytes1)
812  *          || EVP_SignFinal(md_ctx, sigbytes1, &siglen, pkey) <= 0
813  *          || !WPACKET_sub_allocate_bytes_u16(&pkt, siglen, &sigbytes2)
814  *          || sigbytes1 != sigbytes2)
815  *      goto err;
816  */
817 int WPACKET_reserve_bytes(WPACKET *pkt, size_t len, unsigned char **allocbytes);
818 
819 /*
820  * The "reserve_bytes" equivalent of WPACKET_sub_allocate_bytes__()
821  */
822 int WPACKET_sub_reserve_bytes__(WPACKET *pkt, size_t len,
823                                  unsigned char **allocbytes, size_t lenbytes);
824 
825 /*
826  * Convenience macros for  WPACKET_sub_reserve_bytes with different lengths
827  */
828 #define WPACKET_sub_reserve_bytes_u8(pkt, len, bytes) \
829     WPACKET_reserve_bytes__((pkt), (len), (bytes), 1)
830 #define WPACKET_sub_reserve_bytes_u16(pkt, len, bytes) \
831     WPACKET_sub_reserve_bytes__((pkt), (len), (bytes), 2)
832 #define WPACKET_sub_reserve_bytes_u24(pkt, len, bytes) \
833     WPACKET_sub_reserve_bytes__((pkt), (len), (bytes), 3)
834 #define WPACKET_sub_reserve_bytes_u32(pkt, len, bytes) \
835     WPACKET_sub_reserve_bytes__((pkt), (len), (bytes), 4)
836 
837 /*
838  * Write the value stored in |val| into the WPACKET. The value will consume
839  * |bytes| amount of storage. An error will occur if |val| cannot be
840  * accommodated in |bytes| storage, e.g. attempting to write the value 256 into
841  * 1 byte will fail. Don't call this directly. Use the convenience macros below
842  * instead.
843  */
844 int WPACKET_put_bytes__(WPACKET *pkt, uint64_t val, size_t bytes);
845 
846 /*
847  * Convenience macros for calling WPACKET_put_bytes with different
848  * lengths
849  */
850 #define WPACKET_put_bytes_u8(pkt, val) \
851     WPACKET_put_bytes__((pkt), (val), 1)
852 #define WPACKET_put_bytes_u16(pkt, val) \
853     WPACKET_put_bytes__((pkt), (val), 2)
854 #define WPACKET_put_bytes_u24(pkt, val) \
855     WPACKET_put_bytes__((pkt), (val), 3)
856 #define WPACKET_put_bytes_u32(pkt, val) \
857     WPACKET_put_bytes__((pkt), (val), 4)
858 #define WPACKET_put_bytes_u64(pkt, val) \
859     WPACKET_put_bytes__((pkt), (val), 8)
860 
861 /* Set a maximum size that we will not allow the WPACKET to grow beyond */
862 int WPACKET_set_max_size(WPACKET *pkt, size_t maxsize);
863 
864 /* Copy |len| bytes of data from |*src| into the WPACKET. */
865 int WPACKET_memcpy(WPACKET *pkt, const void *src, size_t len);
866 
867 /* Set |len| bytes of data to |ch| into the WPACKET. */
868 int WPACKET_memset(WPACKET *pkt, int ch, size_t len);
869 
870 /*
871  * Copy |len| bytes of data from |*src| into the WPACKET and prefix with its
872  * length (consuming |lenbytes| of data for the length). Don't call this
873  * directly. Use the convenience macros below instead.
874  */
875 int WPACKET_sub_memcpy__(WPACKET *pkt, const void *src, size_t len,
876                        size_t lenbytes);
877 
878 /* Convenience macros for calling WPACKET_sub_memcpy with different lengths */
879 #define WPACKET_sub_memcpy_u8(pkt, src, len) \
880     WPACKET_sub_memcpy__((pkt), (src), (len), 1)
881 #define WPACKET_sub_memcpy_u16(pkt, src, len) \
882     WPACKET_sub_memcpy__((pkt), (src), (len), 2)
883 #define WPACKET_sub_memcpy_u24(pkt, src, len) \
884     WPACKET_sub_memcpy__((pkt), (src), (len), 3)
885 #define WPACKET_sub_memcpy_u32(pkt, src, len) \
886     WPACKET_sub_memcpy__((pkt), (src), (len), 4)
887 
888 /*
889  * Return the total number of bytes written so far to the underlying buffer
890  * including any storage allocated for length bytes
891  */
892 int WPACKET_get_total_written(WPACKET *pkt, size_t *written);
893 
894 /*
895  * Returns the length of the current sub-packet. This excludes any bytes
896  * allocated for the length itself.
897  */
898 int WPACKET_get_length(WPACKET *pkt, size_t *len);
899 
900 /*
901  * Returns a pointer to the current write location, but does not allocate any
902  * bytes.
903  */
904 unsigned char *WPACKET_get_curr(WPACKET *pkt);
905 
906 /* Release resources in a WPACKET if a failure has occurred. */
907 void WPACKET_cleanup(WPACKET *pkt);
908 
909 #endif                          /* OSSL_SSL_PACKET_LOCAL_H */
910