1/***************************************************************************
2 * _ _ ____ _
3 * Project ___| | | | _ \| |
4 * / __| | | | |_) | |
5 * | (__| |_| | _ <| |___
6 * \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) 1998 - 2022, Daniel Stenberg, <[email protected]>, et al.
9 *
10 * This software is licensed as described in the file COPYING, which
11 * you should have received as part of this distribution. The terms
12 * are also available at https://curl.se/docs/copyright.html.
13 *
14 * You may opt to use, copy, modify, merge, publish, distribute and/or sell
15 * copies of the Software, and permit persons to whom the Software is
16 * furnished to do so, under the terms of the COPYING file.
17 *
18 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
19 * KIND, either express or implied.
20 *
21 * SPDX-License-Identifier: curl
22 *
23 ***************************************************************************/
24
25#include "curl_setup.h"
26
27#include "urldata.h"
28#include <curl/curl.h>
29#include <stddef.h>
30
31#ifdef HAVE_ZLIB_H
32#include <zlib.h>
33#endif
34
35#ifdef HAVE_BROTLI
36#include <brotli/decode.h>
37#endif
38
39#ifdef HAVE_ZSTD
40#include <zstd.h>
41#endif
42
43#include "sendf.h"
44#include "http.h"
45#include "content_encoding.h"
46#include "strdup.h"
47#include "strcase.h"
48#include "curl_memory.h"
49#include "memdebug.h"
50
51#define CONTENT_ENCODING_DEFAULT "identity"
52
53#ifndef CURL_DISABLE_HTTP
54
55#define DSIZ CURL_MAX_WRITE_SIZE /* buffer size for decompressed data */
56
57
58#ifdef HAVE_LIBZ
59
60/* Comment this out if zlib is always going to be at least ver. 1.2.0.4
61 (doing so will reduce code size slightly). */
62#define OLD_ZLIB_SUPPORT 1
63
64#define GZIP_MAGIC_0 0x1f
65#define GZIP_MAGIC_1 0x8b
66
67/* gzip flag byte */
68#define ASCII_FLAG 0x01 /* bit 0 set: file probably ascii text */
69#define HEAD_CRC 0x02 /* bit 1 set: header CRC present */
70#define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */
71#define ORIG_NAME 0x08 /* bit 3 set: original file name present */
72#define COMMENT 0x10 /* bit 4 set: file comment present */
73#define RESERVED 0xE0 /* bits 5..7: reserved */
74
75typedef enum {
76 ZLIB_UNINIT, /* uninitialized */
77 ZLIB_INIT, /* initialized */
78 ZLIB_INFLATING, /* inflating started. */
79 ZLIB_EXTERNAL_TRAILER, /* reading external trailer */
80 ZLIB_GZIP_HEADER, /* reading gzip header */
81 ZLIB_GZIP_INFLATING, /* inflating gzip stream */
82 ZLIB_INIT_GZIP /* initialized in transparent gzip mode */
83} zlibInitState;
84
85/* Writer parameters. */
86struct zlib_params {
87 zlibInitState zlib_init; /* zlib init state */
88 uInt trailerlen; /* Remaining trailer byte count. */
89 z_stream z; /* State structure for zlib. */
90};
91
92
93static voidpf
94zalloc_cb(voidpf opaque, unsigned int items, unsigned int size)
95{
96 (void) opaque;
97 /* not a typo, keep it calloc() */
98 return (voidpf) calloc(items, size);
99}
100
101static void
102zfree_cb(voidpf opaque, voidpf ptr)
103{
104 (void) opaque;
105 free(ptr);
106}
107
108static CURLcode
109process_zlib_error(struct Curl_easy *data, z_stream *z)
110{
111 if(z->msg)
112 failf(data, "Error while processing content unencoding: %s",
113 z->msg);
114 else
115 failf(data, "Error while processing content unencoding: "
116 "Unknown failure within decompression software.");
117
118 return CURLE_BAD_CONTENT_ENCODING;
119}
120
121static CURLcode
122exit_zlib(struct Curl_easy *data,
123 z_stream *z, zlibInitState *zlib_init, CURLcode result)
124{
125 if(*zlib_init == ZLIB_GZIP_HEADER)
126 Curl_safefree(z->next_in);
127
128 if(*zlib_init != ZLIB_UNINIT) {
129 if(inflateEnd(z) != Z_OK && result == CURLE_OK)
130 result = process_zlib_error(data, z);
131 *zlib_init = ZLIB_UNINIT;
132 }
133
134 return result;
135}
136
137static CURLcode process_trailer(struct Curl_easy *data,
138 struct zlib_params *zp)
139{
140 z_stream *z = &zp->z;
141 CURLcode result = CURLE_OK;
142 uInt len = z->avail_in < zp->trailerlen? z->avail_in: zp->trailerlen;
143
144 /* Consume expected trailer bytes. Terminate stream if exhausted.
145 Issue an error if unexpected bytes follow. */
146
147 zp->trailerlen -= len;
148 z->avail_in -= len;
149 z->next_in += len;
150 if(z->avail_in)
151 result = CURLE_WRITE_ERROR;
152 if(result || !zp->trailerlen)
153 result = exit_zlib(data, z, &zp->zlib_init, result);
154 else {
155 /* Only occurs for gzip with zlib < 1.2.0.4 or raw deflate. */
156 zp->zlib_init = ZLIB_EXTERNAL_TRAILER;
157 }
158 return result;
159}
160
161static CURLcode inflate_stream(struct Curl_easy *data,
162 struct contenc_writer *writer,
163 zlibInitState started)
164{
165 struct zlib_params *zp = (struct zlib_params *) &writer->params;
166 z_stream *z = &zp->z; /* zlib state structure */
167 uInt nread = z->avail_in;
168 Bytef *orig_in = z->next_in;
169 bool done = FALSE;
170 CURLcode result = CURLE_OK; /* Curl_client_write status */
171 char *decomp; /* Put the decompressed data here. */
172
173 /* Check state. */
174 if(zp->zlib_init != ZLIB_INIT &&
175 zp->zlib_init != ZLIB_INFLATING &&
176 zp->zlib_init != ZLIB_INIT_GZIP &&
177 zp->zlib_init != ZLIB_GZIP_INFLATING)
178 return exit_zlib(data, z, &zp->zlib_init, CURLE_WRITE_ERROR);
179
180 /* Dynamically allocate a buffer for decompression because it's uncommonly
181 large to hold on the stack */
182 decomp = malloc(DSIZ);
183 if(!decomp)
184 return exit_zlib(data, z, &zp->zlib_init, CURLE_OUT_OF_MEMORY);
185
186 /* because the buffer size is fixed, iteratively decompress and transfer to
187 the client via downstream_write function. */
188 while(!done) {
189 int status; /* zlib status */
190 done = TRUE;
191
192 /* (re)set buffer for decompressed output for every iteration */
193 z->next_out = (Bytef *) decomp;
194 z->avail_out = DSIZ;
195
196#ifdef Z_BLOCK
197 /* Z_BLOCK is only available in zlib ver. >= 1.2.0.5 */
198 status = inflate(z, Z_BLOCK);
199#else
200 /* fallback for zlib ver. < 1.2.0.5 */
201 status = inflate(z, Z_SYNC_FLUSH);
202#endif
203
204 /* Flush output data if some. */
205 if(z->avail_out != DSIZ) {
206 if(status == Z_OK || status == Z_STREAM_END) {
207 zp->zlib_init = started; /* Data started. */
208 result = Curl_unencode_write(data, writer->downstream, decomp,
209 DSIZ - z->avail_out);
210 if(result) {
211 exit_zlib(data, z, &zp->zlib_init, result);
212 break;
213 }
214 }
215 }
216
217 /* Dispatch by inflate() status. */
218 switch(status) {
219 case Z_OK:
220 /* Always loop: there may be unflushed latched data in zlib state. */
221 done = FALSE;
222 break;
223 case Z_BUF_ERROR:
224 /* No more data to flush: just exit loop. */
225 break;
226 case Z_STREAM_END:
227 result = process_trailer(data, zp);
228 break;
229 case Z_DATA_ERROR:
230 /* some servers seem to not generate zlib headers, so this is an attempt
231 to fix and continue anyway */
232 if(zp->zlib_init == ZLIB_INIT) {
233 /* Do not use inflateReset2(): only available since zlib 1.2.3.4. */
234 (void) inflateEnd(z); /* don't care about the return code */
235 if(inflateInit2(z, -MAX_WBITS) == Z_OK) {
236 z->next_in = orig_in;
237 z->avail_in = nread;
238 zp->zlib_init = ZLIB_INFLATING;
239 zp->trailerlen = 4; /* Tolerate up to 4 unknown trailer bytes. */
240 done = FALSE;
241 break;
242 }
243 zp->zlib_init = ZLIB_UNINIT; /* inflateEnd() already called. */
244 }
245 result = exit_zlib(data, z, &zp->zlib_init, process_zlib_error(data, z));
246 break;
247 default:
248 result = exit_zlib(data, z, &zp->zlib_init, process_zlib_error(data, z));
249 break;
250 }
251 }
252 free(decomp);
253
254 /* We're about to leave this call so the `nread' data bytes won't be seen
255 again. If we are in a state that would wrongly allow restart in raw mode
256 at the next call, assume output has already started. */
257 if(nread && zp->zlib_init == ZLIB_INIT)
258 zp->zlib_init = started; /* Cannot restart anymore. */
259
260 return result;
261}
262
263
264/* Deflate handler. */
265static CURLcode deflate_init_writer(struct Curl_easy *data,
266 struct contenc_writer *writer)
267{
268 struct zlib_params *zp = (struct zlib_params *) &writer->params;
269 z_stream *z = &zp->z; /* zlib state structure */
270
271 if(!writer->downstream)
272 return CURLE_WRITE_ERROR;
273
274 /* Initialize zlib */
275 z->zalloc = (alloc_func) zalloc_cb;
276 z->zfree = (free_func) zfree_cb;
277
278 if(inflateInit(z) != Z_OK)
279 return process_zlib_error(data, z);
280 zp->zlib_init = ZLIB_INIT;
281 return CURLE_OK;
282}
283
284static CURLcode deflate_unencode_write(struct Curl_easy *data,
285 struct contenc_writer *writer,
286 const char *buf, size_t nbytes)
287{
288 struct zlib_params *zp = (struct zlib_params *) &writer->params;
289 z_stream *z = &zp->z; /* zlib state structure */
290
291 /* Set the compressed input when this function is called */
292 z->next_in = (Bytef *) buf;
293 z->avail_in = (uInt) nbytes;
294
295 if(zp->zlib_init == ZLIB_EXTERNAL_TRAILER)
296 return process_trailer(data, zp);
297
298 /* Now uncompress the data */
299 return inflate_stream(data, writer, ZLIB_INFLATING);
300}
301
302static void deflate_close_writer(struct Curl_easy *data,
303 struct contenc_writer *writer)
304{
305 struct zlib_params *zp = (struct zlib_params *) &writer->params;
306 z_stream *z = &zp->z; /* zlib state structure */
307
308 exit_zlib(data, z, &zp->zlib_init, CURLE_OK);
309}
310
311static const struct content_encoding deflate_encoding = {
312 "deflate",
313 NULL,
314 deflate_init_writer,
315 deflate_unencode_write,
316 deflate_close_writer,
317 sizeof(struct zlib_params)
318};
319
320
321/* Gzip handler. */
322static CURLcode gzip_init_writer(struct Curl_easy *data,
323 struct contenc_writer *writer)
324{
325 struct zlib_params *zp = (struct zlib_params *) &writer->params;
326 z_stream *z = &zp->z; /* zlib state structure */
327
328 if(!writer->downstream)
329 return CURLE_WRITE_ERROR;
330
331 /* Initialize zlib */
332 z->zalloc = (alloc_func) zalloc_cb;
333 z->zfree = (free_func) zfree_cb;
334
335 if(strcmp(zlibVersion(), "1.2.0.4") >= 0) {
336 /* zlib ver. >= 1.2.0.4 supports transparent gzip decompressing */
337 if(inflateInit2(z, MAX_WBITS + 32) != Z_OK) {
338 return process_zlib_error(data, z);
339 }
340 zp->zlib_init = ZLIB_INIT_GZIP; /* Transparent gzip decompress state */
341 }
342 else {
343 /* we must parse the gzip header and trailer ourselves */
344 if(inflateInit2(z, -MAX_WBITS) != Z_OK) {
345 return process_zlib_error(data, z);
346 }
347 zp->trailerlen = 8; /* A CRC-32 and a 32-bit input size (RFC 1952, 2.2) */
348 zp->zlib_init = ZLIB_INIT; /* Initial call state */
349 }
350
351 return CURLE_OK;
352}
353
354#ifdef OLD_ZLIB_SUPPORT
355/* Skip over the gzip header */
356static enum {
357 GZIP_OK,
358 GZIP_BAD,
359 GZIP_UNDERFLOW
360} check_gzip_header(unsigned char const *data, ssize_t len, ssize_t *headerlen)
361{
362 int method, flags;
363 const ssize_t totallen = len;
364
365 /* The shortest header is 10 bytes */
366 if(len < 10)
367 return GZIP_UNDERFLOW;
368
369 if((data[0] != GZIP_MAGIC_0) || (data[1] != GZIP_MAGIC_1))
370 return GZIP_BAD;
371
372 method = data[2];
373 flags = data[3];
374
375 if(method != Z_DEFLATED || (flags & RESERVED) != 0) {
376 /* Can't handle this compression method or unknown flag */
377 return GZIP_BAD;
378 }
379
380 /* Skip over time, xflags, OS code and all previous bytes */
381 len -= 10;
382 data += 10;
383
384 if(flags & EXTRA_FIELD) {
385 ssize_t extra_len;
386
387 if(len < 2)
388 return GZIP_UNDERFLOW;
389
390 extra_len = (data[1] << 8) | data[0];
391
392 if(len < (extra_len + 2))
393 return GZIP_UNDERFLOW;
394
395 len -= (extra_len + 2);
396 data += (extra_len + 2);
397 }
398
399 if(flags & ORIG_NAME) {
400 /* Skip over NUL-terminated file name */
401 while(len && *data) {
402 --len;
403 ++data;
404 }
405 if(!len || *data)
406 return GZIP_UNDERFLOW;
407
408 /* Skip over the NUL */
409 --len;
410 ++data;
411 }
412
413 if(flags & COMMENT) {
414 /* Skip over NUL-terminated comment */
415 while(len && *data) {
416 --len;
417 ++data;
418 }
419 if(!len || *data)
420 return GZIP_UNDERFLOW;
421
422 /* Skip over the NUL */
423 --len;
424 }
425
426 if(flags & HEAD_CRC) {
427 if(len < 2)
428 return GZIP_UNDERFLOW;
429
430 len -= 2;
431 }
432
433 *headerlen = totallen - len;
434 return GZIP_OK;
435}
436#endif
437
438static CURLcode gzip_unencode_write(struct Curl_easy *data,
439 struct contenc_writer *writer,
440 const char *buf, size_t nbytes)
441{
442 struct zlib_params *zp = (struct zlib_params *) &writer->params;
443 z_stream *z = &zp->z; /* zlib state structure */
444
445 if(zp->zlib_init == ZLIB_INIT_GZIP) {
446 /* Let zlib handle the gzip decompression entirely */
447 z->next_in = (Bytef *) buf;
448 z->avail_in = (uInt) nbytes;
449 /* Now uncompress the data */
450 return inflate_stream(data, writer, ZLIB_INIT_GZIP);
451 }
452
453#ifndef OLD_ZLIB_SUPPORT
454 /* Support for old zlib versions is compiled away and we are running with
455 an old version, so return an error. */
456 return exit_zlib(data, z, &zp->zlib_init, CURLE_WRITE_ERROR);
457
458#else
459 /* This next mess is to get around the potential case where there isn't
460 * enough data passed in to skip over the gzip header. If that happens, we
461 * malloc a block and copy what we have then wait for the next call. If
462 * there still isn't enough (this is definitely a worst-case scenario), we
463 * make the block bigger, copy the next part in and keep waiting.
464 *
465 * This is only required with zlib versions < 1.2.0.4 as newer versions
466 * can handle the gzip header themselves.
467 */
468
469 switch(zp->zlib_init) {
470 /* Skip over gzip header? */
471 case ZLIB_INIT:
472 {
473 /* Initial call state */
474 ssize_t hlen;
475
476 switch(check_gzip_header((unsigned char *) buf, nbytes, &hlen)) {
477 case GZIP_OK:
478 z->next_in = (Bytef *) buf + hlen;
479 z->avail_in = (uInt) (nbytes - hlen);
480 zp->zlib_init = ZLIB_GZIP_INFLATING; /* Inflating stream state */
481 break;
482
483 case GZIP_UNDERFLOW:
484 /* We need more data so we can find the end of the gzip header. It's
485 * possible that the memory block we malloc here will never be freed if
486 * the transfer abruptly aborts after this point. Since it's unlikely
487 * that circumstances will be right for this code path to be followed in
488 * the first place, and it's even more unlikely for a transfer to fail
489 * immediately afterwards, it should seldom be a problem.
490 */
491 z->avail_in = (uInt) nbytes;
492 z->next_in = malloc(z->avail_in);
493 if(!z->next_in) {
494 return exit_zlib(data, z, &zp->zlib_init, CURLE_OUT_OF_MEMORY);
495 }
496 memcpy(z->next_in, buf, z->avail_in);
497 zp->zlib_init = ZLIB_GZIP_HEADER; /* Need more gzip header data state */
498 /* We don't have any data to inflate yet */
499 return CURLE_OK;
500
501 case GZIP_BAD:
502 default:
503 return exit_zlib(data, z, &zp->zlib_init, process_zlib_error(data, z));
504 }
505
506 }
507 break;
508
509 case ZLIB_GZIP_HEADER:
510 {
511 /* Need more gzip header data state */
512 ssize_t hlen;
513 z->avail_in += (uInt) nbytes;
514 z->next_in = Curl_saferealloc(z->next_in, z->avail_in);
515 if(!z->next_in) {
516 return exit_zlib(data, z, &zp->zlib_init, CURLE_OUT_OF_MEMORY);
517 }
518 /* Append the new block of data to the previous one */
519 memcpy(z->next_in + z->avail_in - nbytes, buf, nbytes);
520
521 switch(check_gzip_header(z->next_in, z->avail_in, &hlen)) {
522 case GZIP_OK:
523 /* This is the zlib stream data */
524 free(z->next_in);
525 /* Don't point into the malloced block since we just freed it */
526 z->next_in = (Bytef *) buf + hlen + nbytes - z->avail_in;
527 z->avail_in = (uInt) (z->avail_in - hlen);
528 zp->zlib_init = ZLIB_GZIP_INFLATING; /* Inflating stream state */
529 break;
530
531 case GZIP_UNDERFLOW:
532 /* We still don't have any data to inflate! */
533 return CURLE_OK;
534
535 case GZIP_BAD:
536 default:
537 return exit_zlib(data, z, &zp->zlib_init, process_zlib_error(data, z));
538 }
539
540 }
541 break;
542
543 case ZLIB_EXTERNAL_TRAILER:
544 z->next_in = (Bytef *) buf;
545 z->avail_in = (uInt) nbytes;
546 return process_trailer(data, zp);
547
548 case ZLIB_GZIP_INFLATING:
549 default:
550 /* Inflating stream state */
551 z->next_in = (Bytef *) buf;
552 z->avail_in = (uInt) nbytes;
553 break;
554 }
555
556 if(z->avail_in == 0) {
557 /* We don't have any data to inflate; wait until next time */
558 return CURLE_OK;
559 }
560
561 /* We've parsed the header, now uncompress the data */
562 return inflate_stream(data, writer, ZLIB_GZIP_INFLATING);
563#endif
564}
565
566static void gzip_close_writer(struct Curl_easy *data,
567 struct contenc_writer *writer)
568{
569 struct zlib_params *zp = (struct zlib_params *) &writer->params;
570 z_stream *z = &zp->z; /* zlib state structure */
571
572 exit_zlib(data, z, &zp->zlib_init, CURLE_OK);
573}
574
575static const struct content_encoding gzip_encoding = {
576 "gzip",
577 "x-gzip",
578 gzip_init_writer,
579 gzip_unencode_write,
580 gzip_close_writer,
581 sizeof(struct zlib_params)
582};
583
584#endif /* HAVE_LIBZ */
585
586
587#ifdef HAVE_BROTLI
588/* Writer parameters. */
589struct brotli_params {
590 BrotliDecoderState *br; /* State structure for brotli. */
591};
592
593static CURLcode brotli_map_error(BrotliDecoderErrorCode be)
594{
595 switch(be) {
596 case BROTLI_DECODER_ERROR_FORMAT_EXUBERANT_NIBBLE:
597 case BROTLI_DECODER_ERROR_FORMAT_EXUBERANT_META_NIBBLE:
598 case BROTLI_DECODER_ERROR_FORMAT_SIMPLE_HUFFMAN_ALPHABET:
599 case BROTLI_DECODER_ERROR_FORMAT_SIMPLE_HUFFMAN_SAME:
600 case BROTLI_DECODER_ERROR_FORMAT_CL_SPACE:
601 case BROTLI_DECODER_ERROR_FORMAT_HUFFMAN_SPACE:
602 case BROTLI_DECODER_ERROR_FORMAT_CONTEXT_MAP_REPEAT:
603 case BROTLI_DECODER_ERROR_FORMAT_BLOCK_LENGTH_1:
604 case BROTLI_DECODER_ERROR_FORMAT_BLOCK_LENGTH_2:
605 case BROTLI_DECODER_ERROR_FORMAT_TRANSFORM:
606 case BROTLI_DECODER_ERROR_FORMAT_DICTIONARY:
607 case BROTLI_DECODER_ERROR_FORMAT_WINDOW_BITS:
608 case BROTLI_DECODER_ERROR_FORMAT_PADDING_1:
609 case BROTLI_DECODER_ERROR_FORMAT_PADDING_2:
610#ifdef BROTLI_DECODER_ERROR_COMPOUND_DICTIONARY
611 case BROTLI_DECODER_ERROR_COMPOUND_DICTIONARY:
612#endif
613#ifdef BROTLI_DECODER_ERROR_DICTIONARY_NOT_SET
614 case BROTLI_DECODER_ERROR_DICTIONARY_NOT_SET:
615#endif
616 case BROTLI_DECODER_ERROR_INVALID_ARGUMENTS:
617 return CURLE_BAD_CONTENT_ENCODING;
618 case BROTLI_DECODER_ERROR_ALLOC_CONTEXT_MODES:
619 case BROTLI_DECODER_ERROR_ALLOC_TREE_GROUPS:
620 case BROTLI_DECODER_ERROR_ALLOC_CONTEXT_MAP:
621 case BROTLI_DECODER_ERROR_ALLOC_RING_BUFFER_1:
622 case BROTLI_DECODER_ERROR_ALLOC_RING_BUFFER_2:
623 case BROTLI_DECODER_ERROR_ALLOC_BLOCK_TYPE_TREES:
624 return CURLE_OUT_OF_MEMORY;
625 default:
626 break;
627 }
628 return CURLE_WRITE_ERROR;
629}
630
631static CURLcode brotli_init_writer(struct Curl_easy *data,
632 struct contenc_writer *writer)
633{
634 struct brotli_params *bp = (struct brotli_params *) &writer->params;
635 (void) data;
636
637 if(!writer->downstream)
638 return CURLE_WRITE_ERROR;
639
640 bp->br = BrotliDecoderCreateInstance(NULL, NULL, NULL);
641 return bp->br? CURLE_OK: CURLE_OUT_OF_MEMORY;
642}
643
644static CURLcode brotli_unencode_write(struct Curl_easy *data,
645 struct contenc_writer *writer,
646 const char *buf, size_t nbytes)
647{
648 struct brotli_params *bp = (struct brotli_params *) &writer->params;
649 const uint8_t *src = (const uint8_t *) buf;
650 char *decomp;
651 uint8_t *dst;
652 size_t dstleft;
653 CURLcode result = CURLE_OK;
654 BrotliDecoderResult r = BROTLI_DECODER_RESULT_NEEDS_MORE_OUTPUT;
655
656 if(!bp->br)
657 return CURLE_WRITE_ERROR; /* Stream already ended. */
658
659 decomp = malloc(DSIZ);
660 if(!decomp)
661 return CURLE_OUT_OF_MEMORY;
662
663 while((nbytes || r == BROTLI_DECODER_RESULT_NEEDS_MORE_OUTPUT) &&
664 result == CURLE_OK) {
665 dst = (uint8_t *) decomp;
666 dstleft = DSIZ;
667 r = BrotliDecoderDecompressStream(bp->br,
668 &nbytes, &src, &dstleft, &dst, NULL);
669 result = Curl_unencode_write(data, writer->downstream,
670 decomp, DSIZ - dstleft);
671 if(result)
672 break;
673 switch(r) {
674 case BROTLI_DECODER_RESULT_NEEDS_MORE_OUTPUT:
675 case BROTLI_DECODER_RESULT_NEEDS_MORE_INPUT:
676 break;
677 case BROTLI_DECODER_RESULT_SUCCESS:
678 BrotliDecoderDestroyInstance(bp->br);
679 bp->br = NULL;
680 if(nbytes)
681 result = CURLE_WRITE_ERROR;
682 break;
683 default:
684 result = brotli_map_error(BrotliDecoderGetErrorCode(bp->br));
685 break;
686 }
687 }
688 free(decomp);
689 return result;
690}
691
692static void brotli_close_writer(struct Curl_easy *data,
693 struct contenc_writer *writer)
694{
695 struct brotli_params *bp = (struct brotli_params *) &writer->params;
696 (void) data;
697
698 if(bp->br) {
699 BrotliDecoderDestroyInstance(bp->br);
700 bp->br = NULL;
701 }
702}
703
704static const struct content_encoding brotli_encoding = {
705 "br",
706 NULL,
707 brotli_init_writer,
708 brotli_unencode_write,
709 brotli_close_writer,
710 sizeof(struct brotli_params)
711};
712#endif
713
714
715#ifdef HAVE_ZSTD
716/* Writer parameters. */
717struct zstd_params {
718 ZSTD_DStream *zds; /* State structure for zstd. */
719 void *decomp;
720};
721
722static CURLcode zstd_init_writer(struct Curl_easy *data,
723 struct contenc_writer *writer)
724{
725 struct zstd_params *zp = (struct zstd_params *)&writer->params;
726 (void)data;
727
728 if(!writer->downstream)
729 return CURLE_WRITE_ERROR;
730
731 zp->zds = ZSTD_createDStream();
732 zp->decomp = NULL;
733 return zp->zds ? CURLE_OK : CURLE_OUT_OF_MEMORY;
734}
735
736static CURLcode zstd_unencode_write(struct Curl_easy *data,
737 struct contenc_writer *writer,
738 const char *buf, size_t nbytes)
739{
740 CURLcode result = CURLE_OK;
741 struct zstd_params *zp = (struct zstd_params *)&writer->params;
742 ZSTD_inBuffer in;
743 ZSTD_outBuffer out;
744 size_t errorCode;
745
746 if(!zp->decomp) {
747 zp->decomp = malloc(DSIZ);
748 if(!zp->decomp)
749 return CURLE_OUT_OF_MEMORY;
750 }
751 in.pos = 0;
752 in.src = buf;
753 in.size = nbytes;
754
755 for(;;) {
756 out.pos = 0;
757 out.dst = zp->decomp;
758 out.size = DSIZ;
759
760 errorCode = ZSTD_decompressStream(zp->zds, &out, &in);
761 if(ZSTD_isError(errorCode)) {
762 return CURLE_BAD_CONTENT_ENCODING;
763 }
764 if(out.pos > 0) {
765 result = Curl_unencode_write(data, writer->downstream,
766 zp->decomp, out.pos);
767 if(result)
768 break;
769 }
770 if((in.pos == nbytes) && (out.pos < out.size))
771 break;
772 }
773
774 return result;
775}
776
777static void zstd_close_writer(struct Curl_easy *data,
778 struct contenc_writer *writer)
779{
780 struct zstd_params *zp = (struct zstd_params *)&writer->params;
781 (void)data;
782
783 if(zp->decomp) {
784 free(zp->decomp);
785 zp->decomp = NULL;
786 }
787 if(zp->zds) {
788 ZSTD_freeDStream(zp->zds);
789 zp->zds = NULL;
790 }
791}
792
793static const struct content_encoding zstd_encoding = {
794 "zstd",
795 NULL,
796 zstd_init_writer,
797 zstd_unencode_write,
798 zstd_close_writer,
799 sizeof(struct zstd_params)
800};
801#endif
802
803
804/* Identity handler. */
805static CURLcode identity_init_writer(struct Curl_easy *data,
806 struct contenc_writer *writer)
807{
808 (void) data;
809 return writer->downstream? CURLE_OK: CURLE_WRITE_ERROR;
810}
811
812static CURLcode identity_unencode_write(struct Curl_easy *data,
813 struct contenc_writer *writer,
814 const char *buf, size_t nbytes)
815{
816 return Curl_unencode_write(data, writer->downstream, buf, nbytes);
817}
818
819static void identity_close_writer(struct Curl_easy *data,
820 struct contenc_writer *writer)
821{
822 (void) data;
823 (void) writer;
824}
825
826static const struct content_encoding identity_encoding = {
827 "identity",
828 "none",
829 identity_init_writer,
830 identity_unencode_write,
831 identity_close_writer,
832 0
833};
834
835
836/* supported content encodings table. */
837static const struct content_encoding * const encodings[] = {
838 &identity_encoding,
839#ifdef HAVE_LIBZ
840 &deflate_encoding,
841 &gzip_encoding,
842#endif
843#ifdef HAVE_BROTLI
844 &brotli_encoding,
845#endif
846#ifdef HAVE_ZSTD
847 &zstd_encoding,
848#endif
849 NULL
850};
851
852
853/* Return a list of comma-separated names of supported encodings. */
854char *Curl_all_content_encodings(void)
855{
856 size_t len = 0;
857 const struct content_encoding * const *cep;
858 const struct content_encoding *ce;
859 char *ace;
860
861 for(cep = encodings; *cep; cep++) {
862 ce = *cep;
863 if(!strcasecompare(ce->name, CONTENT_ENCODING_DEFAULT))
864 len += strlen(ce->name) + 2;
865 }
866
867 if(!len)
868 return strdup(CONTENT_ENCODING_DEFAULT);
869
870 ace = malloc(len);
871 if(ace) {
872 char *p = ace;
873 for(cep = encodings; *cep; cep++) {
874 ce = *cep;
875 if(!strcasecompare(ce->name, CONTENT_ENCODING_DEFAULT)) {
876 strcpy(p, ce->name);
877 p += strlen(p);
878 *p++ = ',';
879 *p++ = ' ';
880 }
881 }
882 p[-2] = '\0';
883 }
884
885 return ace;
886}
887
888
889/* Real client writer: no downstream. */
890static CURLcode client_init_writer(struct Curl_easy *data,
891 struct contenc_writer *writer)
892{
893 (void) data;
894 return writer->downstream? CURLE_WRITE_ERROR: CURLE_OK;
895}
896
897static CURLcode client_unencode_write(struct Curl_easy *data,
898 struct contenc_writer *writer,
899 const char *buf, size_t nbytes)
900{
901 struct SingleRequest *k = &data->req;
902
903 (void) writer;
904
905 if(!nbytes || k->ignorebody)
906 return CURLE_OK;
907
908 return Curl_client_write(data, CLIENTWRITE_BODY, (char *) buf, nbytes);
909}
910
911static void client_close_writer(struct Curl_easy *data,
912 struct contenc_writer *writer)
913{
914 (void) data;
915 (void) writer;
916}
917
918static const struct content_encoding client_encoding = {
919 NULL,
920 NULL,
921 client_init_writer,
922 client_unencode_write,
923 client_close_writer,
924 0
925};
926
927
928/* Deferred error dummy writer. */
929static CURLcode error_init_writer(struct Curl_easy *data,
930 struct contenc_writer *writer)
931{
932 (void) data;
933 return writer->downstream? CURLE_OK: CURLE_WRITE_ERROR;
934}
935
936static CURLcode error_unencode_write(struct Curl_easy *data,
937 struct contenc_writer *writer,
938 const char *buf, size_t nbytes)
939{
940 char *all = Curl_all_content_encodings();
941
942 (void) writer;
943 (void) buf;
944 (void) nbytes;
945
946 if(!all)
947 return CURLE_OUT_OF_MEMORY;
948 failf(data, "Unrecognized content encoding type. "
949 "libcurl understands %s content encodings.", all);
950 free(all);
951 return CURLE_BAD_CONTENT_ENCODING;
952}
953
954static void error_close_writer(struct Curl_easy *data,
955 struct contenc_writer *writer)
956{
957 (void) data;
958 (void) writer;
959}
960
961static const struct content_encoding error_encoding = {
962 NULL,
963 NULL,
964 error_init_writer,
965 error_unencode_write,
966 error_close_writer,
967 0
968};
969
970/* Create an unencoding writer stage using the given handler. */
971static struct contenc_writer *
972new_unencoding_writer(struct Curl_easy *data,
973 const struct content_encoding *handler,
974 struct contenc_writer *downstream)
975{
976 size_t sz = offsetof(struct contenc_writer, params) + handler->paramsize;
977 struct contenc_writer *writer = (struct contenc_writer *)calloc(1, sz);
978
979 if(writer) {
980 writer->handler = handler;
981 writer->downstream = downstream;
982 if(handler->init_writer(data, writer)) {
983 free(writer);
984 writer = NULL;
985 }
986 }
987
988 return writer;
989}
990
991/* Write data using an unencoding writer stack. "nbytes" is not
992 allowed to be 0. */
993CURLcode Curl_unencode_write(struct Curl_easy *data,
994 struct contenc_writer *writer,
995 const char *buf, size_t nbytes)
996{
997 if(!nbytes)
998 return CURLE_OK;
999 return writer->handler->unencode_write(data, writer, buf, nbytes);
1000}
1001
1002/* Close and clean-up the connection's writer stack. */
1003void Curl_unencode_cleanup(struct Curl_easy *data)
1004{
1005 struct SingleRequest *k = &data->req;
1006 struct contenc_writer *writer = k->writer_stack;
1007
1008 while(writer) {
1009 k->writer_stack = writer->downstream;
1010 writer->handler->close_writer(data, writer);
1011 free(writer);
1012 writer = k->writer_stack;
1013 }
1014}
1015
1016/* Find the content encoding by name. */
1017static const struct content_encoding *find_encoding(const char *name,
1018 size_t len)
1019{
1020 const struct content_encoding * const *cep;
1021
1022 for(cep = encodings; *cep; cep++) {
1023 const struct content_encoding *ce = *cep;
1024 if((strncasecompare(name, ce->name, len) && !ce->name[len]) ||
1025 (ce->alias && strncasecompare(name, ce->alias, len) && !ce->alias[len]))
1026 return ce;
1027 }
1028 return NULL;
1029}
1030
1031/* allow no more than 5 "chained" compression steps */
1032#define MAX_ENCODE_STACK 5
1033
1034/* Set-up the unencoding stack from the Content-Encoding header value.
1035 * See RFC 7231 section 3.1.2.2. */
1036CURLcode Curl_build_unencoding_stack(struct Curl_easy *data,
1037 const char *enclist, int maybechunked)
1038{
1039 struct SingleRequest *k = &data->req;
1040 int counter = 0;
1041
1042 do {
1043 const char *name;
1044 size_t namelen;
1045
1046 /* Parse a single encoding name. */
1047 while(ISSPACE(*enclist) || *enclist == ',')
1048 enclist++;
1049
1050 name = enclist;
1051
1052 for(namelen = 0; *enclist && *enclist != ','; enclist++)
1053 if(!ISSPACE(*enclist))
1054 namelen = enclist - name + 1;
1055
1056 /* Special case: chunked encoding is handled at the reader level. */
1057 if(maybechunked && namelen == 7 && strncasecompare(name, "chunked", 7)) {
1058 k->chunk = TRUE; /* chunks coming our way. */
1059 Curl_httpchunk_init(data); /* init our chunky engine. */
1060 }
1061 else if(namelen) {
1062 const struct content_encoding *encoding = find_encoding(name, namelen);
1063 struct contenc_writer *writer;
1064
1065 if(!k->writer_stack) {
1066 k->writer_stack = new_unencoding_writer(data, &client_encoding, NULL);
1067
1068 if(!k->writer_stack)
1069 return CURLE_OUT_OF_MEMORY;
1070 }
1071
1072 if(!encoding)
1073 encoding = &error_encoding; /* Defer error at stack use. */
1074
1075 if(++counter >= MAX_ENCODE_STACK) {
1076 failf(data, "Reject response due to %u content encodings",
1077 counter);
1078 return CURLE_BAD_CONTENT_ENCODING;
1079 }
1080 /* Stack the unencoding stage. */
1081 writer = new_unencoding_writer(data, encoding, k->writer_stack);
1082 if(!writer)
1083 return CURLE_OUT_OF_MEMORY;
1084 k->writer_stack = writer;
1085 }
1086 } while(*enclist);
1087
1088 return CURLE_OK;
1089}
1090
1091#else
1092/* Stubs for builds without HTTP. */
1093CURLcode Curl_build_unencoding_stack(struct Curl_easy *data,
1094 const char *enclist, int maybechunked)
1095{
1096 (void) data;
1097 (void) enclist;
1098 (void) maybechunked;
1099 return CURLE_NOT_BUILT_IN;
1100}
1101
1102CURLcode Curl_unencode_write(struct Curl_easy *data,
1103 struct contenc_writer *writer,
1104 const char *buf, size_t nbytes)
1105{
1106 (void) data;
1107 (void) writer;
1108 (void) buf;
1109 (void) nbytes;
1110 return CURLE_NOT_BUILT_IN;
1111}
1112
1113void Curl_unencode_cleanup(struct Curl_easy *data)
1114{
1115 (void) data;
1116}
1117
1118char *Curl_all_content_encodings(void)
1119{
1120 return strdup(CONTENT_ENCODING_DEFAULT); /* Satisfy caller. */
1121}
1122
1123#endif /* CURL_DISABLE_HTTP */
1124