xref: /openssl/include/internal/packet.h (revision 7ed6de99)
1 /*
2  * Copyright 2015-2024 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 #ifndef OSSL_INTERNAL_PACKET_H
11 # define OSSL_INTERNAL_PACKET_H
12 # pragma once
13 
14 # include <string.h>
15 # include <openssl/bn.h>
16 # include <openssl/buffer.h>
17 # include <openssl/crypto.h>
18 # include <openssl/e_os2.h>
19 
20 # include "internal/numbers.h"
21 
22 typedef struct {
23     /* Pointer to where we are currently reading from */
24     const unsigned char *curr;
25     /* Number of bytes remaining */
26     size_t remaining;
27 } PACKET;
28 
29 /* Internal unchecked shorthand; don't use outside this file. */
packet_forward(PACKET * pkt,size_t len)30 static ossl_inline void packet_forward(PACKET *pkt, size_t len)
31 {
32     pkt->curr += len;
33     pkt->remaining -= len;
34 }
35 
36 /*
37  * Returns the number of bytes remaining to be read in the PACKET
38  */
PACKET_remaining(const PACKET * pkt)39 static ossl_inline size_t PACKET_remaining(const PACKET *pkt)
40 {
41     return pkt->remaining;
42 }
43 
44 /*
45  * Returns a pointer to the first byte after the packet data.
46  * Useful for integrating with non-PACKET parsing code.
47  * Specifically, we use PACKET_end() to verify that a d2i_... call
48  * has consumed the entire packet contents.
49  */
PACKET_end(const PACKET * pkt)50 static ossl_inline const unsigned char *PACKET_end(const PACKET *pkt)
51 {
52     return pkt->curr + pkt->remaining;
53 }
54 
55 /*
56  * Returns a pointer to the PACKET's current position.
57  * For use in non-PACKETized APIs.
58  */
PACKET_data(const PACKET * pkt)59 static ossl_inline const unsigned char *PACKET_data(const PACKET *pkt)
60 {
61     return pkt->curr;
62 }
63 
64 /*
65  * Initialise a PACKET with |len| bytes held in |buf|. This does not make a
66  * copy of the data so |buf| must be present for the whole time that the PACKET
67  * is being used.
68  */
PACKET_buf_init(PACKET * pkt,const unsigned char * buf,size_t len)69 __owur static ossl_inline int PACKET_buf_init(PACKET *pkt,
70                                               const unsigned char *buf,
71                                               size_t len)
72 {
73     /* Sanity check for negative values. */
74     if (len > (size_t)(SIZE_MAX / 2))
75         return 0;
76 
77     pkt->curr = buf;
78     pkt->remaining = len;
79     return 1;
80 }
81 
82 /* Initialize a PACKET to hold zero bytes. */
PACKET_null_init(PACKET * pkt)83 static ossl_inline void PACKET_null_init(PACKET *pkt)
84 {
85     pkt->curr = NULL;
86     pkt->remaining = 0;
87 }
88 
89 /*
90  * Returns 1 if the packet has length |num| and its contents equal the |num|
91  * bytes read from |ptr|. Returns 0 otherwise (lengths or contents not equal).
92  * If lengths are equal, performs the comparison in constant time.
93  */
PACKET_equal(const PACKET * pkt,const void * ptr,size_t num)94 __owur static ossl_inline int PACKET_equal(const PACKET *pkt, const void *ptr,
95                                            size_t num)
96 {
97     if (PACKET_remaining(pkt) != num)
98         return 0;
99     return CRYPTO_memcmp(pkt->curr, ptr, num) == 0;
100 }
101 
102 /*
103  * Peek ahead and initialize |subpkt| with the next |len| bytes read from |pkt|.
104  * Data is not copied: the |subpkt| packet will share its underlying buffer with
105  * the original |pkt|, so data wrapped by |pkt| must outlive the |subpkt|.
106  */
PACKET_peek_sub_packet(const PACKET * pkt,PACKET * subpkt,size_t len)107 __owur static ossl_inline int PACKET_peek_sub_packet(const PACKET *pkt,
108                                                      PACKET *subpkt, size_t len)
109 {
110     if (PACKET_remaining(pkt) < len)
111         return 0;
112 
113     return PACKET_buf_init(subpkt, pkt->curr, len);
114 }
115 
116 /*
117  * Initialize |subpkt| with the next |len| bytes read from |pkt|. Data is not
118  * copied: the |subpkt| packet will share its underlying buffer with the
119  * original |pkt|, so data wrapped by |pkt| must outlive the |subpkt|.
120  */
PACKET_get_sub_packet(PACKET * pkt,PACKET * subpkt,size_t len)121 __owur static ossl_inline int PACKET_get_sub_packet(PACKET *pkt,
122                                                     PACKET *subpkt, size_t len)
123 {
124     if (!PACKET_peek_sub_packet(pkt, subpkt, len))
125         return 0;
126 
127     packet_forward(pkt, len);
128 
129     return 1;
130 }
131 
132 /*
133  * Peek ahead at 2 bytes in network order from |pkt| and store the value in
134  * |*data|
135  */
PACKET_peek_net_2(const PACKET * pkt,unsigned int * data)136 __owur static ossl_inline int PACKET_peek_net_2(const PACKET *pkt,
137                                                 unsigned int *data)
138 {
139     if (PACKET_remaining(pkt) < 2)
140         return 0;
141 
142     *data = ((unsigned int)(*pkt->curr)) << 8;
143     *data |= *(pkt->curr + 1);
144 
145     return 1;
146 }
147 
148 /* Equivalent of n2s */
149 /* Get 2 bytes in network order from |pkt| and store the value in |*data| */
PACKET_get_net_2(PACKET * pkt,unsigned int * data)150 __owur static ossl_inline int PACKET_get_net_2(PACKET *pkt, unsigned int *data)
151 {
152     if (!PACKET_peek_net_2(pkt, data))
153         return 0;
154 
155     packet_forward(pkt, 2);
156 
157     return 1;
158 }
159 
160 /* Same as PACKET_get_net_2() but for a size_t */
PACKET_get_net_2_len(PACKET * pkt,size_t * data)161 __owur static ossl_inline int PACKET_get_net_2_len(PACKET *pkt, size_t *data)
162 {
163     unsigned int i;
164     int ret = PACKET_get_net_2(pkt, &i);
165 
166     if (ret)
167         *data = (size_t)i;
168 
169     return ret;
170 }
171 
172 /*
173  * Peek ahead at 3 bytes in network order from |pkt| and store the value in
174  * |*data|
175  */
PACKET_peek_net_3(const PACKET * pkt,unsigned long * data)176 __owur static ossl_inline int PACKET_peek_net_3(const PACKET *pkt,
177                                                 unsigned long *data)
178 {
179     if (PACKET_remaining(pkt) < 3)
180         return 0;
181 
182     *data = ((unsigned long)(*pkt->curr)) << 16;
183     *data |= ((unsigned long)(*(pkt->curr + 1))) << 8;
184     *data |= *(pkt->curr + 2);
185 
186     return 1;
187 }
188 
189 /* Equivalent of n2l3 */
190 /* Get 3 bytes in network order from |pkt| and store the value in |*data| */
PACKET_get_net_3(PACKET * pkt,unsigned long * data)191 __owur static ossl_inline int PACKET_get_net_3(PACKET *pkt, unsigned long *data)
192 {
193     if (!PACKET_peek_net_3(pkt, data))
194         return 0;
195 
196     packet_forward(pkt, 3);
197 
198     return 1;
199 }
200 
201 /* Same as PACKET_get_net_3() but for a size_t */
PACKET_get_net_3_len(PACKET * pkt,size_t * data)202 __owur static ossl_inline int PACKET_get_net_3_len(PACKET *pkt, size_t *data)
203 {
204     unsigned long i;
205     int ret = PACKET_get_net_3(pkt, &i);
206 
207     if (ret)
208         *data = (size_t)i;
209 
210     return ret;
211 }
212 
213 /*
214  * Peek ahead at 4 bytes in network order from |pkt| and store the value in
215  * |*data|
216  */
PACKET_peek_net_4(const PACKET * pkt,unsigned long * data)217 __owur static ossl_inline int PACKET_peek_net_4(const PACKET *pkt,
218                                                 unsigned long *data)
219 {
220     if (PACKET_remaining(pkt) < 4)
221         return 0;
222 
223     *data = ((unsigned long)(*pkt->curr)) << 24;
224     *data |= ((unsigned long)(*(pkt->curr + 1))) << 16;
225     *data |= ((unsigned long)(*(pkt->curr + 2))) << 8;
226     *data |= *(pkt->curr + 3);
227 
228     return 1;
229 }
230 
231 /*
232  * Peek ahead at 8 bytes in network order from |pkt| and store the value in
233  * |*data|
234  */
PACKET_peek_net_8(const PACKET * pkt,uint64_t * data)235 __owur static ossl_inline int PACKET_peek_net_8(const PACKET *pkt,
236                                                 uint64_t *data)
237 {
238     if (PACKET_remaining(pkt) < 8)
239         return 0;
240 
241     *data = ((uint64_t)(*pkt->curr)) << 56;
242     *data |= ((uint64_t)(*(pkt->curr + 1))) << 48;
243     *data |= ((uint64_t)(*(pkt->curr + 2))) << 40;
244     *data |= ((uint64_t)(*(pkt->curr + 3))) << 32;
245     *data |= ((uint64_t)(*(pkt->curr + 4))) << 24;
246     *data |= ((uint64_t)(*(pkt->curr + 5))) << 16;
247     *data |= ((uint64_t)(*(pkt->curr + 6))) << 8;
248     *data |= *(pkt->curr + 7);
249 
250     return 1;
251 }
252 
253 /* Equivalent of n2l */
254 /* Get 4 bytes in network order from |pkt| and store the value in |*data| */
PACKET_get_net_4(PACKET * pkt,unsigned long * data)255 __owur static ossl_inline int PACKET_get_net_4(PACKET *pkt, unsigned long *data)
256 {
257     if (!PACKET_peek_net_4(pkt, data))
258         return 0;
259 
260     packet_forward(pkt, 4);
261 
262     return 1;
263 }
264 
265 /* Same as PACKET_get_net_4() but for a size_t */
PACKET_get_net_4_len(PACKET * pkt,size_t * data)266 __owur static ossl_inline int PACKET_get_net_4_len(PACKET *pkt, size_t *data)
267 {
268     unsigned long i;
269     int ret = PACKET_get_net_4(pkt, &i);
270 
271     if (ret)
272         *data = (size_t)i;
273 
274     return ret;
275 }
276 
277 /* Get 8 bytes in network order from |pkt| and store the value in |*data| */
PACKET_get_net_8(PACKET * pkt,uint64_t * data)278 __owur static ossl_inline int PACKET_get_net_8(PACKET *pkt, uint64_t *data)
279 {
280     if (!PACKET_peek_net_8(pkt, data))
281         return 0;
282 
283     packet_forward(pkt, 8);
284 
285     return 1;
286 }
287 
288 /* Peek ahead at 1 byte from |pkt| and store the value in |*data| */
PACKET_peek_1(const PACKET * pkt,unsigned int * data)289 __owur static ossl_inline int PACKET_peek_1(const PACKET *pkt,
290                                             unsigned int *data)
291 {
292     if (!PACKET_remaining(pkt))
293         return 0;
294 
295     *data = *pkt->curr;
296 
297     return 1;
298 }
299 
300 /* Get 1 byte from |pkt| and store the value in |*data| */
PACKET_get_1(PACKET * pkt,unsigned int * data)301 __owur static ossl_inline int PACKET_get_1(PACKET *pkt, unsigned int *data)
302 {
303     if (!PACKET_peek_1(pkt, data))
304         return 0;
305 
306     packet_forward(pkt, 1);
307 
308     return 1;
309 }
310 
311 /* Same as PACKET_get_1() but for a size_t */
PACKET_get_1_len(PACKET * pkt,size_t * data)312 __owur static ossl_inline int PACKET_get_1_len(PACKET *pkt, size_t *data)
313 {
314     unsigned int i;
315     int ret = PACKET_get_1(pkt, &i);
316 
317     if (ret)
318         *data = (size_t)i;
319 
320     return ret;
321 }
322 
323 /*
324  * Peek ahead at 4 bytes in reverse network order from |pkt| and store the value
325  * in |*data|
326  */
PACKET_peek_4(const PACKET * pkt,unsigned long * data)327 __owur static ossl_inline int PACKET_peek_4(const PACKET *pkt,
328                                             unsigned long *data)
329 {
330     if (PACKET_remaining(pkt) < 4)
331         return 0;
332 
333     *data = *pkt->curr;
334     *data |= ((unsigned long)(*(pkt->curr + 1))) << 8;
335     *data |= ((unsigned long)(*(pkt->curr + 2))) << 16;
336     *data |= ((unsigned long)(*(pkt->curr + 3))) << 24;
337 
338     return 1;
339 }
340 
341 /* Equivalent of c2l */
342 /*
343  * Get 4 bytes in reverse network order from |pkt| and store the value in
344  * |*data|
345  */
PACKET_get_4(PACKET * pkt,unsigned long * data)346 __owur static ossl_inline int PACKET_get_4(PACKET *pkt, unsigned long *data)
347 {
348     if (!PACKET_peek_4(pkt, data))
349         return 0;
350 
351     packet_forward(pkt, 4);
352 
353     return 1;
354 }
355 
356 /*
357  * Peek ahead at |len| bytes from the |pkt| and store a pointer to them in
358  * |*data|. This just points at the underlying buffer that |pkt| is using. The
359  * caller should not free this data directly (it will be freed when the
360  * underlying buffer gets freed
361  */
PACKET_peek_bytes(const PACKET * pkt,const unsigned char ** data,size_t len)362 __owur static ossl_inline int PACKET_peek_bytes(const PACKET *pkt,
363                                                 const unsigned char **data,
364                                                 size_t len)
365 {
366     if (PACKET_remaining(pkt) < len)
367         return 0;
368 
369     *data = pkt->curr;
370 
371     return 1;
372 }
373 
374 /*
375  * Read |len| bytes from the |pkt| and store a pointer to them in |*data|. This
376  * just points at the underlying buffer that |pkt| is using. The caller should
377  * not free this data directly (it will be freed when the underlying buffer gets
378  * freed
379  */
PACKET_get_bytes(PACKET * pkt,const unsigned char ** data,size_t len)380 __owur static ossl_inline int PACKET_get_bytes(PACKET *pkt,
381                                                const unsigned char **data,
382                                                size_t len)
383 {
384     if (!PACKET_peek_bytes(pkt, data, len))
385         return 0;
386 
387     packet_forward(pkt, len);
388 
389     return 1;
390 }
391 
392 /* 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)393 __owur static ossl_inline int PACKET_peek_copy_bytes(const PACKET *pkt,
394                                                      unsigned char *data,
395                                                      size_t len)
396 {
397     if (PACKET_remaining(pkt) < len)
398         return 0;
399 
400     memcpy(data, pkt->curr, len);
401 
402     return 1;
403 }
404 
405 /*
406  * Read |len| bytes from |pkt| and copy them to |data|.
407  * The caller is responsible for ensuring that |data| can hold |len| bytes.
408  */
PACKET_copy_bytes(PACKET * pkt,unsigned char * data,size_t len)409 __owur static ossl_inline int PACKET_copy_bytes(PACKET *pkt,
410                                                 unsigned char *data, size_t len)
411 {
412     if (!PACKET_peek_copy_bytes(pkt, data, len))
413         return 0;
414 
415     packet_forward(pkt, len);
416 
417     return 1;
418 }
419 
420 /*
421  * Copy packet data to |dest|, and set |len| to the number of copied bytes.
422  * If the packet has more than |dest_len| bytes, nothing is copied.
423  * Returns 1 if the packet data fits in |dest_len| bytes, 0 otherwise.
424  * Does not forward PACKET position (because it is typically the last thing
425  * done with a given PACKET).
426  */
PACKET_copy_all(const PACKET * pkt,unsigned char * dest,size_t dest_len,size_t * len)427 __owur static ossl_inline int PACKET_copy_all(const PACKET *pkt,
428                                               unsigned char *dest,
429                                               size_t dest_len, size_t *len)
430 {
431     if (PACKET_remaining(pkt) > dest_len) {
432         *len = 0;
433         return 0;
434     }
435     *len = pkt->remaining;
436     memcpy(dest, pkt->curr, pkt->remaining);
437     return 1;
438 }
439 
440 /*
441  * Copy |pkt| bytes to a newly allocated buffer and store a pointer to the
442  * result in |*data|, and the length in |len|.
443  * If |*data| is not NULL, the old data is OPENSSL_free'd.
444  * If the packet is empty, or malloc fails, |*data| will be set to NULL.
445  * Returns 1 if the malloc succeeds and 0 otherwise.
446  * Does not forward PACKET position (because it is typically the last thing
447  * done with a given PACKET).
448  */
PACKET_memdup(const PACKET * pkt,unsigned char ** data,size_t * len)449 __owur static ossl_inline int PACKET_memdup(const PACKET *pkt,
450                                             unsigned char **data, size_t *len)
451 {
452     size_t length;
453 
454     OPENSSL_free(*data);
455     *data = NULL;
456     *len = 0;
457 
458     length = PACKET_remaining(pkt);
459 
460     if (length == 0)
461         return 1;
462 
463     *data = OPENSSL_memdup(pkt->curr, length);
464     if (*data == NULL)
465         return 0;
466 
467     *len = length;
468     return 1;
469 }
470 
471 /*
472  * Read a C string from |pkt| and copy to a newly allocated, NUL-terminated
473  * buffer. Store a pointer to the result in |*data|.
474  * If |*data| is not NULL, the old data is OPENSSL_free'd.
475  * If the data in |pkt| does not contain a NUL-byte, the entire data is
476  * copied and NUL-terminated.
477  * Returns 1 if the malloc succeeds and 0 otherwise.
478  * Does not forward PACKET position (because it is typically the last thing done
479  * with a given PACKET).
480  */
PACKET_strndup(const PACKET * pkt,char ** data)481 __owur static ossl_inline int PACKET_strndup(const PACKET *pkt, char **data)
482 {
483     OPENSSL_free(*data);
484 
485     /* This will succeed on an empty packet, unless pkt->curr == NULL. */
486     *data = OPENSSL_strndup((const char *)pkt->curr, PACKET_remaining(pkt));
487     return (*data != NULL);
488 }
489 
490 /* Returns 1 if |pkt| contains at least one 0-byte, 0 otherwise. */
PACKET_contains_zero_byte(const PACKET * pkt)491 static ossl_inline int PACKET_contains_zero_byte(const PACKET *pkt)
492 {
493     return memchr(pkt->curr, 0, pkt->remaining) != NULL;
494 }
495 
496 /* Move the current reading position forward |len| bytes */
PACKET_forward(PACKET * pkt,size_t len)497 __owur static ossl_inline int PACKET_forward(PACKET *pkt, size_t len)
498 {
499     if (PACKET_remaining(pkt) < len)
500         return 0;
501 
502     packet_forward(pkt, len);
503 
504     return 1;
505 }
506 
507 /*
508  * Reads a variable-length vector prefixed with a one-byte length, and stores
509  * the contents in |subpkt|. |pkt| can equal |subpkt|.
510  * Data is not copied: the |subpkt| packet will share its underlying buffer with
511  * the original |pkt|, so data wrapped by |pkt| must outlive the |subpkt|.
512  * Upon failure, the original |pkt| and |subpkt| are not modified.
513  */
PACKET_get_length_prefixed_1(PACKET * pkt,PACKET * subpkt)514 __owur static ossl_inline int PACKET_get_length_prefixed_1(PACKET *pkt,
515                                                            PACKET *subpkt)
516 {
517     unsigned int length;
518     const unsigned char *data;
519     PACKET tmp = *pkt;
520     if (!PACKET_get_1(&tmp, &length) ||
521         !PACKET_get_bytes(&tmp, &data, (size_t)length)) {
522         return 0;
523     }
524 
525     *pkt = tmp;
526     subpkt->curr = data;
527     subpkt->remaining = length;
528 
529     return 1;
530 }
531 
532 /*
533  * Like PACKET_get_length_prefixed_1, but additionally, fails when there are
534  * leftover bytes in |pkt|.
535  */
PACKET_as_length_prefixed_1(PACKET * pkt,PACKET * subpkt)536 __owur static ossl_inline int PACKET_as_length_prefixed_1(PACKET *pkt,
537                                                           PACKET *subpkt)
538 {
539     unsigned int length;
540     const unsigned char *data;
541     PACKET tmp = *pkt;
542     if (!PACKET_get_1(&tmp, &length) ||
543         !PACKET_get_bytes(&tmp, &data, (size_t)length) ||
544         PACKET_remaining(&tmp) != 0) {
545         return 0;
546     }
547 
548     *pkt = tmp;
549     subpkt->curr = data;
550     subpkt->remaining = length;
551 
552     return 1;
553 }
554 
555 /*
556  * Reads a variable-length vector prefixed with a two-byte length, and stores
557  * the contents in |subpkt|. |pkt| can equal |subpkt|.
558  * Data is not copied: the |subpkt| packet will share its underlying buffer with
559  * the original |pkt|, so data wrapped by |pkt| must outlive the |subpkt|.
560  * Upon failure, the original |pkt| and |subpkt| are not modified.
561  */
PACKET_get_length_prefixed_2(PACKET * pkt,PACKET * subpkt)562 __owur static ossl_inline int PACKET_get_length_prefixed_2(PACKET *pkt,
563                                                            PACKET *subpkt)
564 {
565     unsigned int length;
566     const unsigned char *data;
567     PACKET tmp = *pkt;
568 
569     if (!PACKET_get_net_2(&tmp, &length) ||
570         !PACKET_get_bytes(&tmp, &data, (size_t)length)) {
571         return 0;
572     }
573 
574     *pkt = tmp;
575     subpkt->curr = data;
576     subpkt->remaining = length;
577 
578     return 1;
579 }
580 
581 /*
582  * Like PACKET_get_length_prefixed_2, but additionally, fails when there are
583  * leftover bytes in |pkt|.
584  */
PACKET_as_length_prefixed_2(PACKET * pkt,PACKET * subpkt)585 __owur static ossl_inline int PACKET_as_length_prefixed_2(PACKET *pkt,
586                                                           PACKET *subpkt)
587 {
588     unsigned int length;
589     const unsigned char *data;
590     PACKET tmp = *pkt;
591 
592     if (!PACKET_get_net_2(&tmp, &length) ||
593         !PACKET_get_bytes(&tmp, &data, (size_t)length) ||
594         PACKET_remaining(&tmp) != 0) {
595         return 0;
596     }
597 
598     *pkt = tmp;
599     subpkt->curr = data;
600     subpkt->remaining = length;
601 
602     return 1;
603 }
604 
605 /*
606  * Reads a variable-length vector prefixed with a three-byte length, and stores
607  * the contents in |subpkt|. |pkt| can equal |subpkt|.
608  * Data is not copied: the |subpkt| packet will share its underlying buffer with
609  * the original |pkt|, so data wrapped by |pkt| must outlive the |subpkt|.
610  * Upon failure, the original |pkt| and |subpkt| are not modified.
611  */
PACKET_get_length_prefixed_3(PACKET * pkt,PACKET * subpkt)612 __owur static ossl_inline int PACKET_get_length_prefixed_3(PACKET *pkt,
613                                                            PACKET *subpkt)
614 {
615     unsigned long length;
616     const unsigned char *data;
617     PACKET tmp = *pkt;
618     if (!PACKET_get_net_3(&tmp, &length) ||
619         !PACKET_get_bytes(&tmp, &data, (size_t)length)) {
620         return 0;
621     }
622 
623     *pkt = tmp;
624     subpkt->curr = data;
625     subpkt->remaining = length;
626 
627     return 1;
628 }
629 
630 /* Writable packets */
631 
632 typedef struct wpacket_sub WPACKET_SUB;
633 struct wpacket_sub {
634     /* The parent WPACKET_SUB if we have one or NULL otherwise */
635     WPACKET_SUB *parent;
636 
637     /*
638      * Offset into the buffer where the length of this WPACKET goes. We use an
639      * offset in case the buffer grows and gets reallocated.
640      */
641     size_t packet_len;
642 
643     /* Number of bytes in the packet_len or 0 if we don't write the length */
644     size_t lenbytes;
645 
646     /* Number of bytes written to the buf prior to this packet starting */
647     size_t pwritten;
648 
649     /* Flags for this sub-packet */
650     unsigned int flags;
651 };
652 
653 typedef struct wpacket_st WPACKET;
654 struct wpacket_st {
655     /* The buffer where we store the output data */
656     BUF_MEM *buf;
657 
658     /* Fixed sized buffer which can be used as an alternative to buf */
659     unsigned char *staticbuf;
660 
661     /*
662      * Offset into the buffer where we are currently writing. We use an offset
663      * in case the buffer grows and gets reallocated.
664      */
665     size_t curr;
666 
667     /* Number of bytes written so far */
668     size_t written;
669 
670     /* Maximum number of bytes we will allow to be written to this WPACKET */
671     size_t maxsize;
672 
673     /* Our sub-packets (always at least one if not finished) */
674     WPACKET_SUB *subs;
675 
676     /* Writing from the end first? */
677     unsigned int endfirst : 1;
678 };
679 
680 /* Flags */
681 
682 /* Default */
683 #define WPACKET_FLAGS_NONE                      0
684 
685 /* Error on WPACKET_close() if no data written to the WPACKET */
686 #define WPACKET_FLAGS_NON_ZERO_LENGTH           1
687 
688 /*
689  * Abandon all changes on WPACKET_close() if no data written to the WPACKET,
690  * i.e. this does not write out a zero packet length
691  */
692 #define WPACKET_FLAGS_ABANDON_ON_ZERO_LENGTH    2
693 
694 /* QUIC variable-length integer length prefix */
695 #define WPACKET_FLAGS_QUIC_VLINT                4
696 
697 /*
698  * Initialise a WPACKET with the buffer in |buf|. The buffer must exist
699  * for the whole time that the WPACKET is being used. Additionally |lenbytes| of
700  * data is preallocated at the start of the buffer to store the length of the
701  * WPACKET once we know it.
702  */
703 int WPACKET_init_len(WPACKET *pkt, BUF_MEM *buf, size_t lenbytes);
704 
705 /*
706  * Same as WPACKET_init_len except there is no preallocation of the WPACKET
707  * length.
708  */
709 int WPACKET_init(WPACKET *pkt, BUF_MEM *buf);
710 
711 /*
712  * Same as WPACKET_init_len except there is no underlying buffer. No data is
713  * ever actually written. We just keep track of how much data would have been
714  * written if a buffer was there.
715  */
716 int WPACKET_init_null(WPACKET *pkt, size_t lenbytes);
717 
718 /*
719  * Same as WPACKET_init_null except we set the WPACKET to assume DER length
720  * encoding for sub-packets.
721  */
722 int WPACKET_init_null_der(WPACKET *pkt);
723 
724 /*
725  * Same as WPACKET_init_len except we do not use a growable BUF_MEM structure.
726  * A fixed buffer of memory |buf| of size |len| is used instead. A failure will
727  * occur if you attempt to write beyond the end of the buffer
728  */
729 int WPACKET_init_static_len(WPACKET *pkt, unsigned char *buf, size_t len,
730                             size_t lenbytes);
731 
732 /*
733  * Same as WPACKET_init_static_len except lenbytes is always 0, and we set the
734  * WPACKET to write to the end of the buffer moving towards the start and use
735  * DER length encoding for sub-packets.
736  */
737 int WPACKET_init_der(WPACKET *pkt, unsigned char *buf, size_t len);
738 
739 /*
740  * Set the flags to be applied to the current sub-packet
741  */
742 int WPACKET_set_flags(WPACKET *pkt, unsigned int flags);
743 
744 /*
745  * Closes the most recent sub-packet. It also writes out the length of the
746  * packet to the required location (normally the start of the WPACKET) if
747  * appropriate. The top level WPACKET should be closed using WPACKET_finish()
748  * instead of this function.
749  */
750 int WPACKET_close(WPACKET *pkt);
751 
752 /*
753  * The same as WPACKET_close() but only for the top most WPACKET. Additionally
754  * frees memory resources for this WPACKET.
755  */
756 int WPACKET_finish(WPACKET *pkt);
757 
758 /*
759  * Iterate through all the sub-packets and write out their lengths as if they
760  * were being closed. The lengths will be overwritten with the final lengths
761  * when the sub-packets are eventually closed (which may be different if more
762  * data is added to the WPACKET). This function fails if a sub-packet is of 0
763  * length and WPACKET_FLAGS_ABANDON_ON_ZERO_LENGTH is set.
764  */
765 int WPACKET_fill_lengths(WPACKET *pkt);
766 
767 /*
768  * Initialise a new sub-packet. Additionally |lenbytes| of data is preallocated
769  * at the start of the sub-packet to store its length once we know it. Don't
770  * call this directly. Use the convenience macros below instead.
771  */
772 int WPACKET_start_sub_packet_len__(WPACKET *pkt, size_t lenbytes);
773 
774 /*
775  * Convenience macros for calling WPACKET_start_sub_packet_len with different
776  * lengths
777  */
778 #define WPACKET_start_sub_packet_u8(pkt) \
779     WPACKET_start_sub_packet_len__((pkt), 1)
780 #define WPACKET_start_sub_packet_u16(pkt) \
781     WPACKET_start_sub_packet_len__((pkt), 2)
782 #define WPACKET_start_sub_packet_u24(pkt) \
783     WPACKET_start_sub_packet_len__((pkt), 3)
784 #define WPACKET_start_sub_packet_u32(pkt) \
785     WPACKET_start_sub_packet_len__((pkt), 4)
786 
787 /*
788  * Same as WPACKET_start_sub_packet_len__() except no bytes are pre-allocated
789  * for the sub-packet length.
790  */
791 int WPACKET_start_sub_packet(WPACKET *pkt);
792 
793 /*
794  * Allocate bytes in the WPACKET for the output. This reserves the bytes
795  * and counts them as "written", but doesn't actually do the writing. A pointer
796  * to the allocated bytes is stored in |*allocbytes|. |allocbytes| may be NULL.
797  * WARNING: the allocated bytes must be filled in immediately, without further
798  * WPACKET_* calls. If not then the underlying buffer may be realloc'd and
799  * change its location.
800  */
801 int WPACKET_allocate_bytes(WPACKET *pkt, size_t len,
802                            unsigned char **allocbytes);
803 
804 /*
805  * The same as WPACKET_allocate_bytes() except additionally a new sub-packet is
806  * started for the allocated bytes, and then closed immediately afterwards. The
807  * number of length bytes for the sub-packet is in |lenbytes|. Don't call this
808  * directly. Use the convenience macros below instead.
809  */
810 int WPACKET_sub_allocate_bytes__(WPACKET *pkt, size_t len,
811                                  unsigned char **allocbytes, size_t lenbytes);
812 
813 /*
814  * Convenience macros for calling WPACKET_sub_allocate_bytes with different
815  * lengths
816  */
817 #define WPACKET_sub_allocate_bytes_u8(pkt, len, bytes) \
818     WPACKET_sub_allocate_bytes__((pkt), (len), (bytes), 1)
819 #define WPACKET_sub_allocate_bytes_u16(pkt, len, bytes) \
820     WPACKET_sub_allocate_bytes__((pkt), (len), (bytes), 2)
821 #define WPACKET_sub_allocate_bytes_u24(pkt, len, bytes) \
822     WPACKET_sub_allocate_bytes__((pkt), (len), (bytes), 3)
823 #define WPACKET_sub_allocate_bytes_u32(pkt, len, bytes) \
824     WPACKET_sub_allocate_bytes__((pkt), (len), (bytes), 4)
825 
826 /*
827  * The same as WPACKET_allocate_bytes() except the reserved bytes are not
828  * actually counted as written. Typically this will be for when we don't know
829  * how big arbitrary data is going to be up front, but we do know what the
830  * maximum size will be. If this function is used, then it should be immediately
831  * followed by a WPACKET_allocate_bytes() call before any other WPACKET
832  * functions are called (unless the write to the allocated bytes is abandoned).
833  *
834  * For example: If we are generating a signature, then the size of that
835  * signature may not be known in advance. We can use WPACKET_reserve_bytes() to
836  * handle this:
837  *
838  *  if (!WPACKET_sub_reserve_bytes_u16(&pkt, EVP_PKEY_get_size(pkey), &sigbytes1)
839  *          || EVP_SignFinal(md_ctx, sigbytes1, &siglen, pkey) <= 0
840  *          || !WPACKET_sub_allocate_bytes_u16(&pkt, siglen, &sigbytes2)
841  *          || sigbytes1 != sigbytes2)
842  *      goto err;
843  */
844 int WPACKET_reserve_bytes(WPACKET *pkt, size_t len, unsigned char **allocbytes);
845 
846 /*
847  * The "reserve_bytes" equivalent of WPACKET_sub_allocate_bytes__()
848  */
849 int WPACKET_sub_reserve_bytes__(WPACKET *pkt, size_t len,
850                                  unsigned char **allocbytes, size_t lenbytes);
851 
852 /*
853  * Convenience macros for  WPACKET_sub_reserve_bytes with different lengths
854  */
855 #define WPACKET_sub_reserve_bytes_u8(pkt, len, bytes) \
856     WPACKET_reserve_bytes__((pkt), (len), (bytes), 1)
857 #define WPACKET_sub_reserve_bytes_u16(pkt, len, bytes) \
858     WPACKET_sub_reserve_bytes__((pkt), (len), (bytes), 2)
859 #define WPACKET_sub_reserve_bytes_u24(pkt, len, bytes) \
860     WPACKET_sub_reserve_bytes__((pkt), (len), (bytes), 3)
861 #define WPACKET_sub_reserve_bytes_u32(pkt, len, bytes) \
862     WPACKET_sub_reserve_bytes__((pkt), (len), (bytes), 4)
863 
864 /*
865  * Write the value stored in |val| into the WPACKET. The value will consume
866  * |bytes| amount of storage. An error will occur if |val| cannot be
867  * accommodated in |bytes| storage, e.g. attempting to write the value 256 into
868  * 1 byte will fail. Don't call this directly. Use the convenience macros below
869  * instead.
870  */
871 int WPACKET_put_bytes__(WPACKET *pkt, uint64_t val, size_t bytes);
872 
873 /*
874  * Convenience macros for calling WPACKET_put_bytes with different
875  * lengths
876  */
877 #define WPACKET_put_bytes_u8(pkt, val) \
878     WPACKET_put_bytes__((pkt), (val), 1)
879 #define WPACKET_put_bytes_u16(pkt, val) \
880     WPACKET_put_bytes__((pkt), (val), 2)
881 #define WPACKET_put_bytes_u24(pkt, val) \
882     WPACKET_put_bytes__((pkt), (val), 3)
883 #define WPACKET_put_bytes_u32(pkt, val) \
884     WPACKET_put_bytes__((pkt), (val), 4)
885 #define WPACKET_put_bytes_u64(pkt, val) \
886     WPACKET_put_bytes__((pkt), (val), 8)
887 
888 /* Set a maximum size that we will not allow the WPACKET to grow beyond */
889 int WPACKET_set_max_size(WPACKET *pkt, size_t maxsize);
890 
891 /* Copy |len| bytes of data from |*src| into the WPACKET. */
892 int WPACKET_memcpy(WPACKET *pkt, const void *src, size_t len);
893 
894 /* Set |len| bytes of data to |ch| into the WPACKET. */
895 int WPACKET_memset(WPACKET *pkt, int ch, size_t len);
896 
897 /*
898  * Copy |len| bytes of data from |*src| into the WPACKET and prefix with its
899  * length (consuming |lenbytes| of data for the length). Don't call this
900  * directly. Use the convenience macros below instead.
901  */
902 int WPACKET_sub_memcpy__(WPACKET *pkt, const void *src, size_t len,
903                        size_t lenbytes);
904 
905 /* Convenience macros for calling WPACKET_sub_memcpy with different lengths */
906 #define WPACKET_sub_memcpy_u8(pkt, src, len) \
907     WPACKET_sub_memcpy__((pkt), (src), (len), 1)
908 #define WPACKET_sub_memcpy_u16(pkt, src, len) \
909     WPACKET_sub_memcpy__((pkt), (src), (len), 2)
910 #define WPACKET_sub_memcpy_u24(pkt, src, len) \
911     WPACKET_sub_memcpy__((pkt), (src), (len), 3)
912 #define WPACKET_sub_memcpy_u32(pkt, src, len) \
913     WPACKET_sub_memcpy__((pkt), (src), (len), 4)
914 
915 /*
916  * Return the total number of bytes written so far to the underlying buffer
917  * including any storage allocated for length bytes
918  */
919 int WPACKET_get_total_written(WPACKET *pkt, size_t *written);
920 
921 /*
922  * Returns the length of the current sub-packet. This excludes any bytes
923  * allocated for the length itself.
924  */
925 int WPACKET_get_length(WPACKET *pkt, size_t *len);
926 
927 /*
928  * Returns a pointer to the current write location, but does not allocate any
929  * bytes.
930  */
931 unsigned char *WPACKET_get_curr(WPACKET *pkt);
932 
933 /* Returns true if the underlying buffer is actually NULL */
934 int WPACKET_is_null_buf(WPACKET *pkt);
935 
936 /* Release resources in a WPACKET if a failure has occurred. */
937 void WPACKET_cleanup(WPACKET *pkt);
938 
939 #endif                          /* OSSL_INTERNAL_PACKET_H */
940