Line data Source code
1 : /* inflate.c -- zlib decompression
2 : * Copyright (C) 1995-2005 Mark Adler
3 : * For conditions of distribution and use, see copyright notice in zlib.h
4 : *
5 : * Based on zlib 1.2.3 but modified for the Linux Kernel by
6 : * Richard Purdie <richard@openedhand.com>
7 : *
8 : * Changes mainly for static instead of dynamic memory allocation
9 : *
10 : */
11 :
12 : #include <linux/zutil.h>
13 : #include "inftrees.h"
14 : #include "inflate.h"
15 : #include "inffast.h"
16 : #include "infutil.h"
17 :
18 : /* architecture-specific bits */
19 : #ifdef CONFIG_ZLIB_DFLTCC
20 : # include "../zlib_dfltcc/dfltcc.h"
21 : #else
22 : #define INFLATE_RESET_HOOK(strm) do {} while (0)
23 : #define INFLATE_TYPEDO_HOOK(strm, flush) do {} while (0)
24 : #define INFLATE_NEED_UPDATEWINDOW(strm) 1
25 : #define INFLATE_NEED_CHECKSUM(strm) 1
26 : #endif
27 :
28 0 : int zlib_inflate_workspacesize(void)
29 : {
30 0 : return sizeof(struct inflate_workspace);
31 : }
32 :
33 0 : int zlib_inflateReset(z_streamp strm)
34 : {
35 0 : struct inflate_state *state;
36 :
37 0 : if (strm == NULL || strm->state == NULL) return Z_STREAM_ERROR;
38 0 : state = (struct inflate_state *)strm->state;
39 0 : strm->total_in = strm->total_out = state->total = 0;
40 0 : strm->msg = NULL;
41 0 : strm->adler = 1; /* to support ill-conceived Java test suite */
42 0 : state->mode = HEAD;
43 0 : state->last = 0;
44 0 : state->havedict = 0;
45 0 : state->dmax = 32768U;
46 0 : state->hold = 0;
47 0 : state->bits = 0;
48 0 : state->lencode = state->distcode = state->next = state->codes;
49 :
50 : /* Initialise Window */
51 0 : state->wsize = 1U << state->wbits;
52 0 : state->write = 0;
53 0 : state->whave = 0;
54 :
55 0 : INFLATE_RESET_HOOK(strm);
56 0 : return Z_OK;
57 : }
58 :
59 0 : int zlib_inflateInit2(z_streamp strm, int windowBits)
60 : {
61 0 : struct inflate_state *state;
62 :
63 0 : if (strm == NULL) return Z_STREAM_ERROR;
64 0 : strm->msg = NULL; /* in case we return an error */
65 :
66 0 : state = &WS(strm)->inflate_state;
67 0 : strm->state = (struct internal_state *)state;
68 :
69 0 : if (windowBits < 0) {
70 0 : state->wrap = 0;
71 0 : windowBits = -windowBits;
72 : }
73 : else {
74 0 : state->wrap = (windowBits >> 4) + 1;
75 : }
76 0 : if (windowBits < 8 || windowBits > 15) {
77 : return Z_STREAM_ERROR;
78 : }
79 0 : state->wbits = (unsigned)windowBits;
80 : #ifdef CONFIG_ZLIB_DFLTCC
81 : /*
82 : * DFLTCC requires the window to be page aligned.
83 : * Thus, we overallocate and take the aligned portion of the buffer.
84 : */
85 : state->window = PTR_ALIGN(&WS(strm)->working_window[0], PAGE_SIZE);
86 : #else
87 0 : state->window = &WS(strm)->working_window[0];
88 : #endif
89 :
90 0 : return zlib_inflateReset(strm);
91 : }
92 :
93 : /*
94 : Return state with length and distance decoding tables and index sizes set to
95 : fixed code decoding. This returns fixed tables from inffixed.h.
96 : */
97 0 : static void zlib_fixedtables(struct inflate_state *state)
98 : {
99 : # include "inffixed.h"
100 0 : state->lencode = lenfix;
101 0 : state->lenbits = 9;
102 0 : state->distcode = distfix;
103 0 : state->distbits = 5;
104 : }
105 :
106 :
107 : /*
108 : Update the window with the last wsize (normally 32K) bytes written before
109 : returning. This is only called when a window is already in use, or when
110 : output has been written during this inflate call, but the end of the deflate
111 : stream has not been reached yet. It is also called to window dictionary data
112 : when a dictionary is loaded.
113 :
114 : Providing output buffers larger than 32K to inflate() should provide a speed
115 : advantage, since only the last 32K of output is copied to the sliding window
116 : upon return from inflate(), and since all distances after the first 32K of
117 : output will fall in the output data, making match copies simpler and faster.
118 : The advantage may be dependent on the size of the processor's data caches.
119 : */
120 0 : static void zlib_updatewindow(z_streamp strm, unsigned out)
121 : {
122 0 : struct inflate_state *state;
123 0 : unsigned copy, dist;
124 :
125 0 : state = (struct inflate_state *)strm->state;
126 :
127 : /* copy state->wsize or less output bytes into the circular window */
128 0 : copy = out - strm->avail_out;
129 0 : if (copy >= state->wsize) {
130 0 : memcpy(state->window, strm->next_out - state->wsize, state->wsize);
131 0 : state->write = 0;
132 0 : state->whave = state->wsize;
133 : }
134 : else {
135 0 : dist = state->wsize - state->write;
136 0 : if (dist > copy) dist = copy;
137 0 : memcpy(state->window + state->write, strm->next_out - copy, dist);
138 0 : copy -= dist;
139 0 : if (copy) {
140 0 : memcpy(state->window, strm->next_out - copy, copy);
141 0 : state->write = copy;
142 0 : state->whave = state->wsize;
143 : }
144 : else {
145 0 : state->write += dist;
146 0 : if (state->write == state->wsize) state->write = 0;
147 0 : if (state->whave < state->wsize) state->whave += dist;
148 : }
149 : }
150 0 : }
151 :
152 :
153 : /*
154 : * At the end of a Deflate-compressed PPP packet, we expect to have seen
155 : * a `stored' block type value but not the (zero) length bytes.
156 : */
157 : /*
158 : Returns true if inflate is currently at the end of a block generated by
159 : Z_SYNC_FLUSH or Z_FULL_FLUSH. This function is used by one PPP
160 : implementation to provide an additional safety check. PPP uses
161 : Z_SYNC_FLUSH but removes the length bytes of the resulting empty stored
162 : block. When decompressing, PPP checks that at the end of input packet,
163 : inflate is waiting for these length bytes.
164 : */
165 0 : static int zlib_inflateSyncPacket(z_streamp strm)
166 : {
167 0 : struct inflate_state *state;
168 :
169 0 : if (strm == NULL || strm->state == NULL) return Z_STREAM_ERROR;
170 0 : state = (struct inflate_state *)strm->state;
171 :
172 0 : if (state->mode == STORED && state->bits == 0) {
173 0 : state->mode = TYPE;
174 0 : return Z_OK;
175 : }
176 : return Z_DATA_ERROR;
177 : }
178 :
179 : /* Macros for inflate(): */
180 :
181 : /* check function to use adler32() for zlib or crc32() for gzip */
182 : #define UPDATE(check, buf, len) zlib_adler32(check, buf, len)
183 :
184 : /* Load registers with state in inflate() for speed */
185 : #define LOAD() \
186 : do { \
187 : put = strm->next_out; \
188 : left = strm->avail_out; \
189 : next = strm->next_in; \
190 : have = strm->avail_in; \
191 : hold = state->hold; \
192 : bits = state->bits; \
193 : } while (0)
194 :
195 : /* Restore state from registers in inflate() */
196 : #define RESTORE() \
197 : do { \
198 : strm->next_out = put; \
199 : strm->avail_out = left; \
200 : strm->next_in = next; \
201 : strm->avail_in = have; \
202 : state->hold = hold; \
203 : state->bits = bits; \
204 : } while (0)
205 :
206 : /* Clear the input bit accumulator */
207 : #define INITBITS() \
208 : do { \
209 : hold = 0; \
210 : bits = 0; \
211 : } while (0)
212 :
213 : /* Get a byte of input into the bit accumulator, or return from inflate()
214 : if there is no input available. */
215 : #define PULLBYTE() \
216 : do { \
217 : if (have == 0) goto inf_leave; \
218 : have--; \
219 : hold += (unsigned long)(*next++) << bits; \
220 : bits += 8; \
221 : } while (0)
222 :
223 : /* Assure that there are at least n bits in the bit accumulator. If there is
224 : not enough available input to do that, then return from inflate(). */
225 : #define NEEDBITS(n) \
226 : do { \
227 : while (bits < (unsigned)(n)) \
228 : PULLBYTE(); \
229 : } while (0)
230 :
231 : /* Return the low n bits of the bit accumulator (n < 16) */
232 : #define BITS(n) \
233 : ((unsigned)hold & ((1U << (n)) - 1))
234 :
235 : /* Remove n bits from the bit accumulator */
236 : #define DROPBITS(n) \
237 : do { \
238 : hold >>= (n); \
239 : bits -= (unsigned)(n); \
240 : } while (0)
241 :
242 : /* Remove zero to seven bits as needed to go to a byte boundary */
243 : #define BYTEBITS() \
244 : do { \
245 : hold >>= bits & 7; \
246 : bits -= bits & 7; \
247 : } while (0)
248 :
249 : /*
250 : inflate() uses a state machine to process as much input data and generate as
251 : much output data as possible before returning. The state machine is
252 : structured roughly as follows:
253 :
254 : for (;;) switch (state) {
255 : ...
256 : case STATEn:
257 : if (not enough input data or output space to make progress)
258 : return;
259 : ... make progress ...
260 : state = STATEm;
261 : break;
262 : ...
263 : }
264 :
265 : so when inflate() is called again, the same case is attempted again, and
266 : if the appropriate resources are provided, the machine proceeds to the
267 : next state. The NEEDBITS() macro is usually the way the state evaluates
268 : whether it can proceed or should return. NEEDBITS() does the return if
269 : the requested bits are not available. The typical use of the BITS macros
270 : is:
271 :
272 : NEEDBITS(n);
273 : ... do something with BITS(n) ...
274 : DROPBITS(n);
275 :
276 : where NEEDBITS(n) either returns from inflate() if there isn't enough
277 : input left to load n bits into the accumulator, or it continues. BITS(n)
278 : gives the low n bits in the accumulator. When done, DROPBITS(n) drops
279 : the low n bits off the accumulator. INITBITS() clears the accumulator
280 : and sets the number of available bits to zero. BYTEBITS() discards just
281 : enough bits to put the accumulator on a byte boundary. After BYTEBITS()
282 : and a NEEDBITS(8), then BITS(8) would return the next byte in the stream.
283 :
284 : NEEDBITS(n) uses PULLBYTE() to get an available byte of input, or to return
285 : if there is no input available. The decoding of variable length codes uses
286 : PULLBYTE() directly in order to pull just enough bytes to decode the next
287 : code, and no more.
288 :
289 : Some states loop until they get enough input, making sure that enough
290 : state information is maintained to continue the loop where it left off
291 : if NEEDBITS() returns in the loop. For example, want, need, and keep
292 : would all have to actually be part of the saved state in case NEEDBITS()
293 : returns:
294 :
295 : case STATEw:
296 : while (want < need) {
297 : NEEDBITS(n);
298 : keep[want++] = BITS(n);
299 : DROPBITS(n);
300 : }
301 : state = STATEx;
302 : case STATEx:
303 :
304 : As shown above, if the next state is also the next case, then the break
305 : is omitted.
306 :
307 : A state may also return if there is not enough output space available to
308 : complete that state. Those states are copying stored data, writing a
309 : literal byte, and copying a matching string.
310 :
311 : When returning, a "goto inf_leave" is used to update the total counters,
312 : update the check value, and determine whether any progress has been made
313 : during that inflate() call in order to return the proper return code.
314 : Progress is defined as a change in either strm->avail_in or strm->avail_out.
315 : When there is a window, goto inf_leave will update the window with the last
316 : output written. If a goto inf_leave occurs in the middle of decompression
317 : and there is no window currently, goto inf_leave will create one and copy
318 : output to the window for the next call of inflate().
319 :
320 : In this implementation, the flush parameter of inflate() only affects the
321 : return code (per zlib.h). inflate() always writes as much as possible to
322 : strm->next_out, given the space available and the provided input--the effect
323 : documented in zlib.h of Z_SYNC_FLUSH. Furthermore, inflate() always defers
324 : the allocation of and copying into a sliding window until necessary, which
325 : provides the effect documented in zlib.h for Z_FINISH when the entire input
326 : stream available. So the only thing the flush parameter actually does is:
327 : when flush is set to Z_FINISH, inflate() cannot return Z_OK. Instead it
328 : will return Z_BUF_ERROR if it has not reached the end of the stream.
329 : */
330 :
331 0 : int zlib_inflate(z_streamp strm, int flush)
332 : {
333 0 : struct inflate_state *state;
334 0 : const unsigned char *next; /* next input */
335 0 : unsigned char *put; /* next output */
336 0 : unsigned have, left; /* available input and output */
337 0 : unsigned long hold; /* bit buffer */
338 0 : unsigned bits; /* bits in bit buffer */
339 0 : unsigned in, out; /* save starting available input and output */
340 0 : unsigned copy; /* number of stored or match bytes to copy */
341 0 : unsigned char *from; /* where to copy match bytes from */
342 0 : code this; /* current decoding table entry */
343 0 : code last; /* parent table entry */
344 0 : unsigned len; /* length to copy for repeats, bits to drop */
345 0 : int ret; /* return code */
346 0 : static const unsigned short order[19] = /* permutation of code lengths */
347 : {16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15};
348 :
349 : /* Do not check for strm->next_out == NULL here as ppc zImage
350 : inflates to strm->next_out = 0 */
351 :
352 0 : if (strm == NULL || strm->state == NULL ||
353 0 : (strm->next_in == NULL && strm->avail_in != 0))
354 : return Z_STREAM_ERROR;
355 :
356 0 : state = (struct inflate_state *)strm->state;
357 :
358 0 : if (state->mode == TYPE) state->mode = TYPEDO; /* skip check */
359 0 : LOAD();
360 0 : in = have;
361 0 : out = left;
362 0 : ret = Z_OK;
363 0 : for (;;)
364 0 : switch (state->mode) {
365 0 : case HEAD:
366 0 : if (state->wrap == 0) {
367 0 : state->mode = TYPEDO;
368 0 : break;
369 : }
370 0 : NEEDBITS(16);
371 0 : if (
372 0 : ((BITS(8) << 8) + (hold >> 8)) % 31) {
373 0 : strm->msg = (char *)"incorrect header check";
374 0 : state->mode = BAD;
375 0 : break;
376 : }
377 0 : if (BITS(4) != Z_DEFLATED) {
378 0 : strm->msg = (char *)"unknown compression method";
379 0 : state->mode = BAD;
380 0 : break;
381 : }
382 0 : DROPBITS(4);
383 0 : len = BITS(4) + 8;
384 0 : if (len > state->wbits) {
385 0 : strm->msg = (char *)"invalid window size";
386 0 : state->mode = BAD;
387 0 : break;
388 : }
389 0 : state->dmax = 1U << len;
390 0 : strm->adler = state->check = zlib_adler32(0L, NULL, 0);
391 0 : state->mode = hold & 0x200 ? DICTID : TYPE;
392 0 : INITBITS();
393 0 : break;
394 : case DICTID:
395 0 : NEEDBITS(32);
396 0 : strm->adler = state->check = REVERSE(hold);
397 0 : INITBITS();
398 0 : state->mode = DICT;
399 0 : fallthrough;
400 0 : case DICT:
401 0 : if (state->havedict == 0) {
402 0 : RESTORE();
403 0 : return Z_NEED_DICT;
404 : }
405 0 : strm->adler = state->check = zlib_adler32(0L, NULL, 0);
406 0 : state->mode = TYPE;
407 0 : fallthrough;
408 0 : case TYPE:
409 0 : if (flush == Z_BLOCK) goto inf_leave;
410 0 : fallthrough;
411 : case TYPEDO:
412 0 : INFLATE_TYPEDO_HOOK(strm, flush);
413 0 : if (state->last) {
414 0 : BYTEBITS();
415 0 : state->mode = CHECK;
416 0 : break;
417 : }
418 0 : NEEDBITS(3);
419 0 : state->last = BITS(1);
420 0 : DROPBITS(1);
421 0 : switch (BITS(2)) {
422 0 : case 0: /* stored block */
423 0 : state->mode = STORED;
424 0 : break;
425 : case 1: /* fixed block */
426 0 : zlib_fixedtables(state);
427 0 : state->mode = LEN; /* decode codes */
428 0 : break;
429 0 : case 2: /* dynamic block */
430 0 : state->mode = TABLE;
431 0 : break;
432 0 : case 3:
433 0 : strm->msg = (char *)"invalid block type";
434 0 : state->mode = BAD;
435 : }
436 0 : DROPBITS(2);
437 0 : break;
438 0 : case STORED:
439 0 : BYTEBITS(); /* go to byte boundary */
440 0 : NEEDBITS(32);
441 0 : if ((hold & 0xffff) != ((hold >> 16) ^ 0xffff)) {
442 0 : strm->msg = (char *)"invalid stored block lengths";
443 0 : state->mode = BAD;
444 0 : break;
445 : }
446 0 : state->length = (unsigned)hold & 0xffff;
447 0 : INITBITS();
448 0 : state->mode = COPY;
449 0 : fallthrough;
450 0 : case COPY:
451 0 : copy = state->length;
452 0 : if (copy) {
453 0 : if (copy > have) copy = have;
454 0 : if (copy > left) copy = left;
455 0 : if (copy == 0) goto inf_leave;
456 0 : memcpy(put, next, copy);
457 0 : have -= copy;
458 0 : next += copy;
459 0 : left -= copy;
460 0 : put += copy;
461 0 : state->length -= copy;
462 0 : break;
463 : }
464 0 : state->mode = TYPE;
465 0 : break;
466 : case TABLE:
467 0 : NEEDBITS(14);
468 0 : state->nlen = BITS(5) + 257;
469 0 : DROPBITS(5);
470 0 : state->ndist = BITS(5) + 1;
471 0 : DROPBITS(5);
472 0 : state->ncode = BITS(4) + 4;
473 0 : DROPBITS(4);
474 : #ifndef PKZIP_BUG_WORKAROUND
475 0 : if (state->nlen > 286 || state->ndist > 30) {
476 0 : strm->msg = (char *)"too many length or distance symbols";
477 0 : state->mode = BAD;
478 0 : break;
479 : }
480 : #endif
481 0 : state->have = 0;
482 0 : state->mode = LENLENS;
483 : fallthrough;
484 : case LENLENS:
485 0 : while (state->have < state->ncode) {
486 0 : NEEDBITS(3);
487 0 : state->lens[order[state->have++]] = (unsigned short)BITS(3);
488 0 : DROPBITS(3);
489 : }
490 0 : while (state->have < 19)
491 0 : state->lens[order[state->have++]] = 0;
492 0 : state->next = state->codes;
493 0 : state->lencode = (code const *)(state->next);
494 0 : state->lenbits = 7;
495 0 : ret = zlib_inflate_table(CODES, state->lens, 19, &(state->next),
496 0 : &(state->lenbits), state->work);
497 0 : if (ret) {
498 0 : strm->msg = (char *)"invalid code lengths set";
499 0 : state->mode = BAD;
500 0 : break;
501 : }
502 0 : state->have = 0;
503 0 : state->mode = CODELENS;
504 : fallthrough;
505 : case CODELENS:
506 0 : while (state->have < state->nlen + state->ndist) {
507 0 : for (;;) {
508 0 : this = state->lencode[BITS(state->lenbits)];
509 0 : if ((unsigned)(this.bits) <= bits) break;
510 0 : PULLBYTE();
511 : }
512 0 : if (this.val < 16) {
513 0 : NEEDBITS(this.bits);
514 0 : DROPBITS(this.bits);
515 0 : state->lens[state->have++] = this.val;
516 : }
517 : else {
518 0 : if (this.val == 16) {
519 0 : NEEDBITS(this.bits + 2);
520 0 : DROPBITS(this.bits);
521 0 : if (state->have == 0) {
522 0 : strm->msg = (char *)"invalid bit length repeat";
523 0 : state->mode = BAD;
524 0 : break;
525 : }
526 0 : len = state->lens[state->have - 1];
527 0 : copy = 3 + BITS(2);
528 0 : DROPBITS(2);
529 : }
530 0 : else if (this.val == 17) {
531 0 : NEEDBITS(this.bits + 3);
532 0 : DROPBITS(this.bits);
533 0 : len = 0;
534 0 : copy = 3 + BITS(3);
535 0 : DROPBITS(3);
536 : }
537 : else {
538 0 : NEEDBITS(this.bits + 7);
539 0 : DROPBITS(this.bits);
540 0 : len = 0;
541 0 : copy = 11 + BITS(7);
542 0 : DROPBITS(7);
543 : }
544 0 : if (state->have + copy > state->nlen + state->ndist) {
545 0 : strm->msg = (char *)"invalid bit length repeat";
546 0 : state->mode = BAD;
547 0 : break;
548 : }
549 0 : while (copy--)
550 0 : state->lens[state->have++] = (unsigned short)len;
551 : }
552 : }
553 :
554 : /* handle error breaks in while */
555 0 : if (state->mode == BAD) break;
556 :
557 : /* build code tables */
558 0 : state->next = state->codes;
559 0 : state->lencode = (code const *)(state->next);
560 0 : state->lenbits = 9;
561 0 : ret = zlib_inflate_table(LENS, state->lens, state->nlen, &(state->next),
562 0 : &(state->lenbits), state->work);
563 0 : if (ret) {
564 0 : strm->msg = (char *)"invalid literal/lengths set";
565 0 : state->mode = BAD;
566 0 : break;
567 : }
568 0 : state->distcode = (code const *)(state->next);
569 0 : state->distbits = 6;
570 0 : ret = zlib_inflate_table(DISTS, state->lens + state->nlen, state->ndist,
571 : &(state->next), &(state->distbits), state->work);
572 0 : if (ret) {
573 0 : strm->msg = (char *)"invalid distances set";
574 0 : state->mode = BAD;
575 0 : break;
576 : }
577 0 : state->mode = LEN;
578 0 : fallthrough;
579 0 : case LEN:
580 0 : if (have >= 6 && left >= 258) {
581 0 : RESTORE();
582 0 : inflate_fast(strm, out);
583 0 : LOAD();
584 0 : break;
585 : }
586 0 : for (;;) {
587 0 : this = state->lencode[BITS(state->lenbits)];
588 0 : if ((unsigned)(this.bits) <= bits) break;
589 0 : PULLBYTE();
590 : }
591 0 : if (this.op && (this.op & 0xf0) == 0) {
592 0 : last = this;
593 0 : for (;;) {
594 0 : this = state->lencode[last.val +
595 0 : (BITS(last.bits + last.op) >> last.bits)];
596 0 : if ((unsigned)(last.bits + this.bits) <= bits) break;
597 0 : PULLBYTE();
598 : }
599 0 : DROPBITS(last.bits);
600 : }
601 0 : DROPBITS(this.bits);
602 0 : state->length = (unsigned)this.val;
603 0 : if ((int)(this.op) == 0) {
604 0 : state->mode = LIT;
605 0 : break;
606 : }
607 0 : if (this.op & 32) {
608 0 : state->mode = TYPE;
609 0 : break;
610 : }
611 0 : if (this.op & 64) {
612 0 : strm->msg = (char *)"invalid literal/length code";
613 0 : state->mode = BAD;
614 0 : break;
615 : }
616 0 : state->extra = (unsigned)(this.op) & 15;
617 0 : state->mode = LENEXT;
618 0 : fallthrough;
619 0 : case LENEXT:
620 0 : if (state->extra) {
621 0 : NEEDBITS(state->extra);
622 0 : state->length += BITS(state->extra);
623 0 : DROPBITS(state->extra);
624 : }
625 0 : state->mode = DIST;
626 0 : fallthrough;
627 0 : case DIST:
628 0 : for (;;) {
629 0 : this = state->distcode[BITS(state->distbits)];
630 0 : if ((unsigned)(this.bits) <= bits) break;
631 0 : PULLBYTE();
632 : }
633 0 : if ((this.op & 0xf0) == 0) {
634 0 : last = this;
635 0 : for (;;) {
636 0 : this = state->distcode[last.val +
637 0 : (BITS(last.bits + last.op) >> last.bits)];
638 0 : if ((unsigned)(last.bits + this.bits) <= bits) break;
639 0 : PULLBYTE();
640 : }
641 0 : DROPBITS(last.bits);
642 : }
643 0 : DROPBITS(this.bits);
644 0 : if (this.op & 64) {
645 0 : strm->msg = (char *)"invalid distance code";
646 0 : state->mode = BAD;
647 0 : break;
648 : }
649 0 : state->offset = (unsigned)this.val;
650 0 : state->extra = (unsigned)(this.op) & 15;
651 0 : state->mode = DISTEXT;
652 0 : fallthrough;
653 0 : case DISTEXT:
654 0 : if (state->extra) {
655 0 : NEEDBITS(state->extra);
656 0 : state->offset += BITS(state->extra);
657 0 : DROPBITS(state->extra);
658 : }
659 : #ifdef INFLATE_STRICT
660 : if (state->offset > state->dmax) {
661 : strm->msg = (char *)"invalid distance too far back";
662 : state->mode = BAD;
663 : break;
664 : }
665 : #endif
666 0 : if (state->offset > state->whave + out - left) {
667 0 : strm->msg = (char *)"invalid distance too far back";
668 0 : state->mode = BAD;
669 0 : break;
670 : }
671 0 : state->mode = MATCH;
672 0 : fallthrough;
673 0 : case MATCH:
674 0 : if (left == 0) goto inf_leave;
675 0 : copy = out - left;
676 0 : if (state->offset > copy) { /* copy from window */
677 0 : copy = state->offset - copy;
678 0 : if (copy > state->write) {
679 0 : copy -= state->write;
680 0 : from = state->window + (state->wsize - copy);
681 : }
682 : else
683 0 : from = state->window + (state->write - copy);
684 0 : if (copy > state->length) copy = state->length;
685 : }
686 : else { /* copy from output */
687 0 : from = put - state->offset;
688 0 : copy = state->length;
689 : }
690 0 : if (copy > left) copy = left;
691 0 : left -= copy;
692 0 : state->length -= copy;
693 0 : do {
694 0 : *put++ = *from++;
695 0 : } while (--copy);
696 0 : if (state->length == 0) state->mode = LEN;
697 : break;
698 0 : case LIT:
699 0 : if (left == 0) goto inf_leave;
700 0 : *put++ = (unsigned char)(state->length);
701 0 : left--;
702 0 : state->mode = LEN;
703 0 : break;
704 0 : case CHECK:
705 0 : if (state->wrap) {
706 0 : NEEDBITS(32);
707 0 : out -= left;
708 0 : strm->total_out += out;
709 0 : state->total += out;
710 0 : if (INFLATE_NEED_CHECKSUM(strm) && out)
711 0 : strm->adler = state->check =
712 0 : UPDATE(state->check, put - out, out);
713 0 : out = left;
714 0 : if ((
715 0 : REVERSE(hold)) != state->check) {
716 0 : strm->msg = (char *)"incorrect data check";
717 0 : state->mode = BAD;
718 0 : break;
719 : }
720 0 : INITBITS();
721 : }
722 0 : state->mode = DONE;
723 0 : fallthrough;
724 0 : case DONE:
725 0 : ret = Z_STREAM_END;
726 0 : goto inf_leave;
727 0 : case BAD:
728 0 : ret = Z_DATA_ERROR;
729 0 : goto inf_leave;
730 : case MEM:
731 : return Z_MEM_ERROR;
732 0 : case SYNC:
733 : default:
734 0 : return Z_STREAM_ERROR;
735 : }
736 :
737 : /*
738 : Return from inflate(), updating the total counts and the check value.
739 : If there was no progress during the inflate() call, return a buffer
740 : error. Call zlib_updatewindow() to create and/or update the window state.
741 : */
742 0 : inf_leave:
743 0 : RESTORE();
744 0 : if (INFLATE_NEED_UPDATEWINDOW(strm) &&
745 0 : (state->wsize || (state->mode < CHECK && out != strm->avail_out)))
746 0 : zlib_updatewindow(strm, out);
747 :
748 0 : in -= strm->avail_in;
749 0 : out -= strm->avail_out;
750 0 : strm->total_in += in;
751 0 : strm->total_out += out;
752 0 : state->total += out;
753 0 : if (INFLATE_NEED_CHECKSUM(strm) && state->wrap && out)
754 0 : strm->adler = state->check =
755 0 : UPDATE(state->check, strm->next_out - out, out);
756 :
757 0 : strm->data_type = state->bits + (state->last ? 64 : 0) +
758 0 : (state->mode == TYPE ? 128 : 0);
759 :
760 0 : if (flush == Z_PACKET_FLUSH && ret == Z_OK &&
761 0 : strm->avail_out != 0 && strm->avail_in == 0)
762 0 : return zlib_inflateSyncPacket(strm);
763 :
764 0 : if (((in == 0 && out == 0) || flush == Z_FINISH) && ret == Z_OK)
765 0 : ret = Z_BUF_ERROR;
766 :
767 : return ret;
768 : }
769 :
770 0 : int zlib_inflateEnd(z_streamp strm)
771 : {
772 0 : if (strm == NULL || strm->state == NULL)
773 0 : return Z_STREAM_ERROR;
774 : return Z_OK;
775 : }
776 :
777 : /*
778 : * This subroutine adds the data at next_in/avail_in to the output history
779 : * without performing any output. The output buffer must be "caught up";
780 : * i.e. no pending output but this should always be the case. The state must
781 : * be waiting on the start of a block (i.e. mode == TYPE or HEAD). On exit,
782 : * the output will also be caught up, and the checksum will have been updated
783 : * if need be.
784 : */
785 0 : int zlib_inflateIncomp(z_stream *z)
786 : {
787 0 : struct inflate_state *state = (struct inflate_state *)z->state;
788 0 : Byte *saved_no = z->next_out;
789 0 : uInt saved_ao = z->avail_out;
790 :
791 0 : if (state->mode != TYPE && state->mode != HEAD)
792 : return Z_DATA_ERROR;
793 :
794 : /* Setup some variables to allow misuse of updateWindow */
795 0 : z->avail_out = 0;
796 0 : z->next_out = (unsigned char*)z->next_in + z->avail_in;
797 :
798 0 : zlib_updatewindow(z, z->avail_in);
799 :
800 : /* Restore saved variables */
801 0 : z->avail_out = saved_ao;
802 0 : z->next_out = saved_no;
803 :
804 0 : z->adler = state->check =
805 0 : UPDATE(state->check, z->next_in, z->avail_in);
806 :
807 0 : z->total_out += z->avail_in;
808 0 : z->total_in += z->avail_in;
809 0 : z->next_in += z->avail_in;
810 0 : state->total += z->avail_in;
811 0 : z->avail_in = 0;
812 :
813 0 : return Z_OK;
814 : }
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