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-rw-r--r--lib/xz/xz_dec_stream.c821
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diff --git a/lib/xz/xz_dec_stream.c b/lib/xz/xz_dec_stream.c
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1/*
2 * .xz Stream decoder
3 *
4 * Author: Lasse Collin <lasse.collin@tukaani.org>
5 *
6 * This file has been put into the public domain.
7 * You can do whatever you want with this file.
8 */
9
10#include "xz_private.h"
11#include "xz_stream.h"
12
13/* Hash used to validate the Index field */
14struct xz_dec_hash {
15 vli_type unpadded;
16 vli_type uncompressed;
17 uint32_t crc32;
18};
19
20struct xz_dec {
21 /* Position in dec_main() */
22 enum {
23 SEQ_STREAM_HEADER,
24 SEQ_BLOCK_START,
25 SEQ_BLOCK_HEADER,
26 SEQ_BLOCK_UNCOMPRESS,
27 SEQ_BLOCK_PADDING,
28 SEQ_BLOCK_CHECK,
29 SEQ_INDEX,
30 SEQ_INDEX_PADDING,
31 SEQ_INDEX_CRC32,
32 SEQ_STREAM_FOOTER
33 } sequence;
34
35 /* Position in variable-length integers and Check fields */
36 uint32_t pos;
37
38 /* Variable-length integer decoded by dec_vli() */
39 vli_type vli;
40
41 /* Saved in_pos and out_pos */
42 size_t in_start;
43 size_t out_start;
44
45 /* CRC32 value in Block or Index */
46 uint32_t crc32;
47
48 /* Type of the integrity check calculated from uncompressed data */
49 enum xz_check check_type;
50
51 /* Operation mode */
52 enum xz_mode mode;
53
54 /*
55 * True if the next call to xz_dec_run() is allowed to return
56 * XZ_BUF_ERROR.
57 */
58 bool allow_buf_error;
59
60 /* Information stored in Block Header */
61 struct {
62 /*
63 * Value stored in the Compressed Size field, or
64 * VLI_UNKNOWN if Compressed Size is not present.
65 */
66 vli_type compressed;
67
68 /*
69 * Value stored in the Uncompressed Size field, or
70 * VLI_UNKNOWN if Uncompressed Size is not present.
71 */
72 vli_type uncompressed;
73
74 /* Size of the Block Header field */
75 uint32_t size;
76 } block_header;
77
78 /* Information collected when decoding Blocks */
79 struct {
80 /* Observed compressed size of the current Block */
81 vli_type compressed;
82
83 /* Observed uncompressed size of the current Block */
84 vli_type uncompressed;
85
86 /* Number of Blocks decoded so far */
87 vli_type count;
88
89 /*
90 * Hash calculated from the Block sizes. This is used to
91 * validate the Index field.
92 */
93 struct xz_dec_hash hash;
94 } block;
95
96 /* Variables needed when verifying the Index field */
97 struct {
98 /* Position in dec_index() */
99 enum {
100 SEQ_INDEX_COUNT,
101 SEQ_INDEX_UNPADDED,
102 SEQ_INDEX_UNCOMPRESSED
103 } sequence;
104
105 /* Size of the Index in bytes */
106 vli_type size;
107
108 /* Number of Records (matches block.count in valid files) */
109 vli_type count;
110
111 /*
112 * Hash calculated from the Records (matches block.hash in
113 * valid files).
114 */
115 struct xz_dec_hash hash;
116 } index;
117
118 /*
119 * Temporary buffer needed to hold Stream Header, Block Header,
120 * and Stream Footer. The Block Header is the biggest (1 KiB)
121 * so we reserve space according to that. buf[] has to be aligned
122 * to a multiple of four bytes; the size_t variables before it
123 * should guarantee this.
124 */
125 struct {
126 size_t pos;
127 size_t size;
128 uint8_t buf[1024];
129 } temp;
130
131 struct xz_dec_lzma2 *lzma2;
132
133#ifdef XZ_DEC_BCJ
134 struct xz_dec_bcj *bcj;
135 bool bcj_active;
136#endif
137};
138
139#ifdef XZ_DEC_ANY_CHECK
140/* Sizes of the Check field with different Check IDs */
141static const uint8_t check_sizes[16] = {
142 0,
143 4, 4, 4,
144 8, 8, 8,
145 16, 16, 16,
146 32, 32, 32,
147 64, 64, 64
148};
149#endif
150
151/*
152 * Fill s->temp by copying data starting from b->in[b->in_pos]. Caller
153 * must have set s->temp.pos to indicate how much data we are supposed
154 * to copy into s->temp.buf. Return true once s->temp.pos has reached
155 * s->temp.size.
156 */
157static bool fill_temp(struct xz_dec *s, struct xz_buf *b)
158{
159 size_t copy_size = min_t(size_t,
160 b->in_size - b->in_pos, s->temp.size - s->temp.pos);
161
162 memcpy(s->temp.buf + s->temp.pos, b->in + b->in_pos, copy_size);
163 b->in_pos += copy_size;
164 s->temp.pos += copy_size;
165
166 if (s->temp.pos == s->temp.size) {
167 s->temp.pos = 0;
168 return true;
169 }
170
171 return false;
172}
173
174/* Decode a variable-length integer (little-endian base-128 encoding) */
175static enum xz_ret dec_vli(struct xz_dec *s, const uint8_t *in,
176 size_t *in_pos, size_t in_size)
177{
178 uint8_t byte;
179
180 if (s->pos == 0)
181 s->vli = 0;
182
183 while (*in_pos < in_size) {
184 byte = in[*in_pos];
185 ++*in_pos;
186
187 s->vli |= (vli_type)(byte & 0x7F) << s->pos;
188
189 if ((byte & 0x80) == 0) {
190 /* Don't allow non-minimal encodings. */
191 if (byte == 0 && s->pos != 0)
192 return XZ_DATA_ERROR;
193
194 s->pos = 0;
195 return XZ_STREAM_END;
196 }
197
198 s->pos += 7;
199 if (s->pos == 7 * VLI_BYTES_MAX)
200 return XZ_DATA_ERROR;
201 }
202
203 return XZ_OK;
204}
205
206/*
207 * Decode the Compressed Data field from a Block. Update and validate
208 * the observed compressed and uncompressed sizes of the Block so that
209 * they don't exceed the values possibly stored in the Block Header
210 * (validation assumes that no integer overflow occurs, since vli_type
211 * is normally uint64_t). Update the CRC32 if presence of the CRC32
212 * field was indicated in Stream Header.
213 *
214 * Once the decoding is finished, validate that the observed sizes match
215 * the sizes possibly stored in the Block Header. Update the hash and
216 * Block count, which are later used to validate the Index field.
217 */
218static enum xz_ret dec_block(struct xz_dec *s, struct xz_buf *b)
219{
220 enum xz_ret ret;
221
222 s->in_start = b->in_pos;
223 s->out_start = b->out_pos;
224
225#ifdef XZ_DEC_BCJ
226 if (s->bcj_active)
227 ret = xz_dec_bcj_run(s->bcj, s->lzma2, b);
228 else
229#endif
230 ret = xz_dec_lzma2_run(s->lzma2, b);
231
232 s->block.compressed += b->in_pos - s->in_start;
233 s->block.uncompressed += b->out_pos - s->out_start;
234
235 /*
236 * There is no need to separately check for VLI_UNKNOWN, since
237 * the observed sizes are always smaller than VLI_UNKNOWN.
238 */
239 if (s->block.compressed > s->block_header.compressed
240 || s->block.uncompressed
241 > s->block_header.uncompressed)
242 return XZ_DATA_ERROR;
243
244 if (s->check_type == XZ_CHECK_CRC32)
245 s->crc32 = xz_crc32(b->out + s->out_start,
246 b->out_pos - s->out_start, s->crc32);
247
248 if (ret == XZ_STREAM_END) {
249 if (s->block_header.compressed != VLI_UNKNOWN
250 && s->block_header.compressed
251 != s->block.compressed)
252 return XZ_DATA_ERROR;
253
254 if (s->block_header.uncompressed != VLI_UNKNOWN
255 && s->block_header.uncompressed
256 != s->block.uncompressed)
257 return XZ_DATA_ERROR;
258
259 s->block.hash.unpadded += s->block_header.size
260 + s->block.compressed;
261
262#ifdef XZ_DEC_ANY_CHECK
263 s->block.hash.unpadded += check_sizes[s->check_type];
264#else
265 if (s->check_type == XZ_CHECK_CRC32)
266 s->block.hash.unpadded += 4;
267#endif
268
269 s->block.hash.uncompressed += s->block.uncompressed;
270 s->block.hash.crc32 = xz_crc32(
271 (const uint8_t *)&s->block.hash,
272 sizeof(s->block.hash), s->block.hash.crc32);
273
274 ++s->block.count;
275 }
276
277 return ret;
278}
279
280/* Update the Index size and the CRC32 value. */
281static void index_update(struct xz_dec *s, const struct xz_buf *b)
282{
283 size_t in_used = b->in_pos - s->in_start;
284 s->index.size += in_used;
285 s->crc32 = xz_crc32(b->in + s->in_start, in_used, s->crc32);
286}
287
288/*
289 * Decode the Number of Records, Unpadded Size, and Uncompressed Size
290 * fields from the Index field. That is, Index Padding and CRC32 are not
291 * decoded by this function.
292 *
293 * This can return XZ_OK (more input needed), XZ_STREAM_END (everything
294 * successfully decoded), or XZ_DATA_ERROR (input is corrupt).
295 */
296static enum xz_ret dec_index(struct xz_dec *s, struct xz_buf *b)
297{
298 enum xz_ret ret;
299
300 do {
301 ret = dec_vli(s, b->in, &b->in_pos, b->in_size);
302 if (ret != XZ_STREAM_END) {
303 index_update(s, b);
304 return ret;
305 }
306
307 switch (s->index.sequence) {
308 case SEQ_INDEX_COUNT:
309 s->index.count = s->vli;
310
311 /*
312 * Validate that the Number of Records field
313 * indicates the same number of Records as
314 * there were Blocks in the Stream.
315 */
316 if (s->index.count != s->block.count)
317 return XZ_DATA_ERROR;
318
319 s->index.sequence = SEQ_INDEX_UNPADDED;
320 break;
321
322 case SEQ_INDEX_UNPADDED:
323 s->index.hash.unpadded += s->vli;
324 s->index.sequence = SEQ_INDEX_UNCOMPRESSED;
325 break;
326
327 case SEQ_INDEX_UNCOMPRESSED:
328 s->index.hash.uncompressed += s->vli;
329 s->index.hash.crc32 = xz_crc32(
330 (const uint8_t *)&s->index.hash,
331 sizeof(s->index.hash),
332 s->index.hash.crc32);
333 --s->index.count;
334 s->index.sequence = SEQ_INDEX_UNPADDED;
335 break;
336 }
337 } while (s->index.count > 0);
338
339 return XZ_STREAM_END;
340}
341
342/*
343 * Validate that the next four input bytes match the value of s->crc32.
344 * s->pos must be zero when starting to validate the first byte.
345 */
346static enum xz_ret crc32_validate(struct xz_dec *s, struct xz_buf *b)
347{
348 do {
349 if (b->in_pos == b->in_size)
350 return XZ_OK;
351
352 if (((s->crc32 >> s->pos) & 0xFF) != b->in[b->in_pos++])
353 return XZ_DATA_ERROR;
354
355 s->pos += 8;
356
357 } while (s->pos < 32);
358
359 s->crc32 = 0;
360 s->pos = 0;
361
362 return XZ_STREAM_END;
363}
364
365#ifdef XZ_DEC_ANY_CHECK
366/*
367 * Skip over the Check field when the Check ID is not supported.
368 * Returns true once the whole Check field has been skipped over.
369 */
370static bool check_skip(struct xz_dec *s, struct xz_buf *b)
371{
372 while (s->pos < check_sizes[s->check_type]) {
373 if (b->in_pos == b->in_size)
374 return false;
375
376 ++b->in_pos;
377 ++s->pos;
378 }
379
380 s->pos = 0;
381
382 return true;
383}
384#endif
385
386/* Decode the Stream Header field (the first 12 bytes of the .xz Stream). */
387static enum xz_ret dec_stream_header(struct xz_dec *s)
388{
389 if (!memeq(s->temp.buf, HEADER_MAGIC, HEADER_MAGIC_SIZE))
390 return XZ_FORMAT_ERROR;
391
392 if (xz_crc32(s->temp.buf + HEADER_MAGIC_SIZE, 2, 0)
393 != get_le32(s->temp.buf + HEADER_MAGIC_SIZE + 2))
394 return XZ_DATA_ERROR;
395
396 if (s->temp.buf[HEADER_MAGIC_SIZE] != 0)
397 return XZ_OPTIONS_ERROR;
398
399 /*
400 * Of integrity checks, we support only none (Check ID = 0) and
401 * CRC32 (Check ID = 1). However, if XZ_DEC_ANY_CHECK is defined,
402 * we will accept other check types too, but then the check won't
403 * be verified and a warning (XZ_UNSUPPORTED_CHECK) will be given.
404 */
405 s->check_type = s->temp.buf[HEADER_MAGIC_SIZE + 1];
406
407#ifdef XZ_DEC_ANY_CHECK
408 if (s->check_type > XZ_CHECK_MAX)
409 return XZ_OPTIONS_ERROR;
410
411 if (s->check_type > XZ_CHECK_CRC32)
412 return XZ_UNSUPPORTED_CHECK;
413#else
414 if (s->check_type > XZ_CHECK_CRC32)
415 return XZ_OPTIONS_ERROR;
416#endif
417
418 return XZ_OK;
419}
420
421/* Decode the Stream Footer field (the last 12 bytes of the .xz Stream) */
422static enum xz_ret dec_stream_footer(struct xz_dec *s)
423{
424 if (!memeq(s->temp.buf + 10, FOOTER_MAGIC, FOOTER_MAGIC_SIZE))
425 return XZ_DATA_ERROR;
426
427 if (xz_crc32(s->temp.buf + 4, 6, 0) != get_le32(s->temp.buf))
428 return XZ_DATA_ERROR;
429
430 /*
431 * Validate Backward Size. Note that we never added the size of the
432 * Index CRC32 field to s->index.size, thus we use s->index.size / 4
433 * instead of s->index.size / 4 - 1.
434 */
435 if ((s->index.size >> 2) != get_le32(s->temp.buf + 4))
436 return XZ_DATA_ERROR;
437
438 if (s->temp.buf[8] != 0 || s->temp.buf[9] != s->check_type)
439 return XZ_DATA_ERROR;
440
441 /*
442 * Use XZ_STREAM_END instead of XZ_OK to be more convenient
443 * for the caller.
444 */
445 return XZ_STREAM_END;
446}
447
448/* Decode the Block Header and initialize the filter chain. */
449static enum xz_ret dec_block_header(struct xz_dec *s)
450{
451 enum xz_ret ret;
452
453 /*
454 * Validate the CRC32. We know that the temp buffer is at least
455 * eight bytes so this is safe.
456 */
457 s->temp.size -= 4;
458 if (xz_crc32(s->temp.buf, s->temp.size, 0)
459 != get_le32(s->temp.buf + s->temp.size))
460 return XZ_DATA_ERROR;
461
462 s->temp.pos = 2;
463
464 /*
465 * Catch unsupported Block Flags. We support only one or two filters
466 * in the chain, so we catch that with the same test.
467 */
468#ifdef XZ_DEC_BCJ
469 if (s->temp.buf[1] & 0x3E)
470#else
471 if (s->temp.buf[1] & 0x3F)
472#endif
473 return XZ_OPTIONS_ERROR;
474
475 /* Compressed Size */
476 if (s->temp.buf[1] & 0x40) {
477 if (dec_vli(s, s->temp.buf, &s->temp.pos, s->temp.size)
478 != XZ_STREAM_END)
479 return XZ_DATA_ERROR;
480
481 s->block_header.compressed = s->vli;
482 } else {
483 s->block_header.compressed = VLI_UNKNOWN;
484 }
485
486 /* Uncompressed Size */
487 if (s->temp.buf[1] & 0x80) {
488 if (dec_vli(s, s->temp.buf, &s->temp.pos, s->temp.size)
489 != XZ_STREAM_END)
490 return XZ_DATA_ERROR;
491
492 s->block_header.uncompressed = s->vli;
493 } else {
494 s->block_header.uncompressed = VLI_UNKNOWN;
495 }
496
497#ifdef XZ_DEC_BCJ
498 /* If there are two filters, the first one must be a BCJ filter. */
499 s->bcj_active = s->temp.buf[1] & 0x01;
500 if (s->bcj_active) {
501 if (s->temp.size - s->temp.pos < 2)
502 return XZ_OPTIONS_ERROR;
503
504 ret = xz_dec_bcj_reset(s->bcj, s->temp.buf[s->temp.pos++]);
505 if (ret != XZ_OK)
506 return ret;
507
508 /*
509 * We don't support custom start offset,
510 * so Size of Properties must be zero.
511 */
512 if (s->temp.buf[s->temp.pos++] != 0x00)
513 return XZ_OPTIONS_ERROR;
514 }
515#endif
516
517 /* Valid Filter Flags always take at least two bytes. */
518 if (s->temp.size - s->temp.pos < 2)
519 return XZ_DATA_ERROR;
520
521 /* Filter ID = LZMA2 */
522 if (s->temp.buf[s->temp.pos++] != 0x21)
523 return XZ_OPTIONS_ERROR;
524
525 /* Size of Properties = 1-byte Filter Properties */
526 if (s->temp.buf[s->temp.pos++] != 0x01)
527 return XZ_OPTIONS_ERROR;
528
529 /* Filter Properties contains LZMA2 dictionary size. */
530 if (s->temp.size - s->temp.pos < 1)
531 return XZ_DATA_ERROR;
532
533 ret = xz_dec_lzma2_reset(s->lzma2, s->temp.buf[s->temp.pos++]);
534 if (ret != XZ_OK)
535 return ret;
536
537 /* The rest must be Header Padding. */
538 while (s->temp.pos < s->temp.size)
539 if (s->temp.buf[s->temp.pos++] != 0x00)
540 return XZ_OPTIONS_ERROR;
541
542 s->temp.pos = 0;
543 s->block.compressed = 0;
544 s->block.uncompressed = 0;
545
546 return XZ_OK;
547}
548
549static enum xz_ret dec_main(struct xz_dec *s, struct xz_buf *b)
550{
551 enum xz_ret ret;
552
553 /*
554 * Store the start position for the case when we are in the middle
555 * of the Index field.
556 */
557 s->in_start = b->in_pos;
558
559 while (true) {
560 switch (s->sequence) {
561 case SEQ_STREAM_HEADER:
562 /*
563 * Stream Header is copied to s->temp, and then
564 * decoded from there. This way if the caller
565 * gives us only little input at a time, we can
566 * still keep the Stream Header decoding code
567 * simple. Similar approach is used in many places
568 * in this file.
569 */
570 if (!fill_temp(s, b))
571 return XZ_OK;
572
573 /*
574 * If dec_stream_header() returns
575 * XZ_UNSUPPORTED_CHECK, it is still possible
576 * to continue decoding if working in multi-call
577 * mode. Thus, update s->sequence before calling
578 * dec_stream_header().
579 */
580 s->sequence = SEQ_BLOCK_START;
581
582 ret = dec_stream_header(s);
583 if (ret != XZ_OK)
584 return ret;
585
586 case SEQ_BLOCK_START:
587 /* We need one byte of input to continue. */
588 if (b->in_pos == b->in_size)
589 return XZ_OK;
590
591 /* See if this is the beginning of the Index field. */
592 if (b->in[b->in_pos] == 0) {
593 s->in_start = b->in_pos++;
594 s->sequence = SEQ_INDEX;
595 break;
596 }
597
598 /*
599 * Calculate the size of the Block Header and
600 * prepare to decode it.
601 */
602 s->block_header.size
603 = ((uint32_t)b->in[b->in_pos] + 1) * 4;
604
605 s->temp.size = s->block_header.size;
606 s->temp.pos = 0;
607 s->sequence = SEQ_BLOCK_HEADER;
608
609 case SEQ_BLOCK_HEADER:
610 if (!fill_temp(s, b))
611 return XZ_OK;
612
613 ret = dec_block_header(s);
614 if (ret != XZ_OK)
615 return ret;
616
617 s->sequence = SEQ_BLOCK_UNCOMPRESS;
618
619 case SEQ_BLOCK_UNCOMPRESS:
620 ret = dec_block(s, b);
621 if (ret != XZ_STREAM_END)
622 return ret;
623
624 s->sequence = SEQ_BLOCK_PADDING;
625
626 case SEQ_BLOCK_PADDING:
627 /*
628 * Size of Compressed Data + Block Padding
629 * must be a multiple of four. We don't need
630 * s->block.compressed for anything else
631 * anymore, so we use it here to test the size
632 * of the Block Padding field.
633 */
634 while (s->block.compressed & 3) {
635 if (b->in_pos == b->in_size)
636 return XZ_OK;
637
638 if (b->in[b->in_pos++] != 0)
639 return XZ_DATA_ERROR;
640
641 ++s->block.compressed;
642 }
643
644 s->sequence = SEQ_BLOCK_CHECK;
645
646 case SEQ_BLOCK_CHECK:
647 if (s->check_type == XZ_CHECK_CRC32) {
648 ret = crc32_validate(s, b);
649 if (ret != XZ_STREAM_END)
650 return ret;
651 }
652#ifdef XZ_DEC_ANY_CHECK
653 else if (!check_skip(s, b)) {
654 return XZ_OK;
655 }
656#endif
657
658 s->sequence = SEQ_BLOCK_START;
659 break;
660
661 case SEQ_INDEX:
662 ret = dec_index(s, b);
663 if (ret != XZ_STREAM_END)
664 return ret;
665
666 s->sequence = SEQ_INDEX_PADDING;
667
668 case SEQ_INDEX_PADDING:
669 while ((s->index.size + (b->in_pos - s->in_start))
670 & 3) {
671 if (b->in_pos == b->in_size) {
672 index_update(s, b);
673 return XZ_OK;
674 }
675
676 if (b->in[b->in_pos++] != 0)
677 return XZ_DATA_ERROR;
678 }
679
680 /* Finish the CRC32 value and Index size. */
681 index_update(s, b);
682
683 /* Compare the hashes to validate the Index field. */
684 if (!memeq(&s->block.hash, &s->index.hash,
685 sizeof(s->block.hash)))
686 return XZ_DATA_ERROR;
687
688 s->sequence = SEQ_INDEX_CRC32;
689
690 case SEQ_INDEX_CRC32:
691 ret = crc32_validate(s, b);
692 if (ret != XZ_STREAM_END)
693 return ret;
694
695 s->temp.size = STREAM_HEADER_SIZE;
696 s->sequence = SEQ_STREAM_FOOTER;
697
698 case SEQ_STREAM_FOOTER:
699 if (!fill_temp(s, b))
700 return XZ_OK;
701
702 return dec_stream_footer(s);
703 }
704 }
705
706 /* Never reached */
707}
708
709/*
710 * xz_dec_run() is a wrapper for dec_main() to handle some special cases in
711 * multi-call and single-call decoding.
712 *
713 * In multi-call mode, we must return XZ_BUF_ERROR when it seems clear that we
714 * are not going to make any progress anymore. This is to prevent the caller
715 * from calling us infinitely when the input file is truncated or otherwise
716 * corrupt. Since zlib-style API allows that the caller fills the input buffer
717 * only when the decoder doesn't produce any new output, we have to be careful
718 * to avoid returning XZ_BUF_ERROR too easily: XZ_BUF_ERROR is returned only
719 * after the second consecutive call to xz_dec_run() that makes no progress.
720 *
721 * In single-call mode, if we couldn't decode everything and no error
722 * occurred, either the input is truncated or the output buffer is too small.
723 * Since we know that the last input byte never produces any output, we know
724 * that if all the input was consumed and decoding wasn't finished, the file
725 * must be corrupt. Otherwise the output buffer has to be too small or the
726 * file is corrupt in a way that decoding it produces too big output.
727 *
728 * If single-call decoding fails, we reset b->in_pos and b->out_pos back to
729 * their original values. This is because with some filter chains there won't
730 * be any valid uncompressed data in the output buffer unless the decoding
731 * actually succeeds (that's the price to pay of using the output buffer as
732 * the workspace).
733 */
734XZ_EXTERN enum xz_ret xz_dec_run(struct xz_dec *s, struct xz_buf *b)
735{
736 size_t in_start;
737 size_t out_start;
738 enum xz_ret ret;
739
740 if (DEC_IS_SINGLE(s->mode))
741 xz_dec_reset(s);
742
743 in_start = b->in_pos;
744 out_start = b->out_pos;
745 ret = dec_main(s, b);
746
747 if (DEC_IS_SINGLE(s->mode)) {
748 if (ret == XZ_OK)
749 ret = b->in_pos == b->in_size
750 ? XZ_DATA_ERROR : XZ_BUF_ERROR;
751
752 if (ret != XZ_STREAM_END) {
753 b->in_pos = in_start;
754 b->out_pos = out_start;
755 }
756
757 } else if (ret == XZ_OK && in_start == b->in_pos
758 && out_start == b->out_pos) {
759 if (s->allow_buf_error)
760 ret = XZ_BUF_ERROR;
761
762 s->allow_buf_error = true;
763 } else {
764 s->allow_buf_error = false;
765 }
766
767 return ret;
768}
769
770XZ_EXTERN struct xz_dec *xz_dec_init(enum xz_mode mode, uint32_t dict_max)
771{
772 struct xz_dec *s = kmalloc(sizeof(*s), GFP_KERNEL);
773 if (s == NULL)
774 return NULL;
775
776 s->mode = mode;
777
778#ifdef XZ_DEC_BCJ
779 s->bcj = xz_dec_bcj_create(DEC_IS_SINGLE(mode));
780 if (s->bcj == NULL)
781 goto error_bcj;
782#endif
783
784 s->lzma2 = xz_dec_lzma2_create(mode, dict_max);
785 if (s->lzma2 == NULL)
786 goto error_lzma2;
787
788 xz_dec_reset(s);
789 return s;
790
791error_lzma2:
792#ifdef XZ_DEC_BCJ
793 xz_dec_bcj_end(s->bcj);
794error_bcj:
795#endif
796 kfree(s);
797 return NULL;
798}
799
800XZ_EXTERN void xz_dec_reset(struct xz_dec *s)
801{
802 s->sequence = SEQ_STREAM_HEADER;
803 s->allow_buf_error = false;
804 s->pos = 0;
805 s->crc32 = 0;
806 memzero(&s->block, sizeof(s->block));
807 memzero(&s->index, sizeof(s->index));
808 s->temp.pos = 0;
809 s->temp.size = STREAM_HEADER_SIZE;
810}
811
812XZ_EXTERN void xz_dec_end(struct xz_dec *s)
813{
814 if (s != NULL) {
815 xz_dec_lzma2_end(s->lzma2);
816#ifdef XZ_DEC_BCJ
817 xz_dec_bcj_end(s->bcj);
818#endif
819 kfree(s);
820 }
821}
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-11 11:40:52 -0500