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1 | |
2 /* pngrutil.c - utilities to read a PNG file | |
3 * | |
4 * Last changed in libpng 1.6.20 [December 3, 2015] | |
5 * Copyright (c) 1998-2015 Glenn Randers-Pehrson | |
6 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) | |
7 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) | |
8 * | |
9 * This code is released under the libpng license. | |
10 * For conditions of distribution and use, see the disclaimer | |
11 * and license in png.h | |
12 * | |
13 * This file contains routines that are only called from within | |
14 * libpng itself during the course of reading an image. | |
15 */ | |
16 | |
17 #include "pngpriv.h" | |
18 | |
19 #ifdef PNG_READ_SUPPORTED | |
20 | |
21 png_uint_32 PNGAPI | |
22 png_get_uint_31(png_const_structrp png_ptr, png_const_bytep buf) | |
23 { | |
24 png_uint_32 uval = png_get_uint_32(buf); | |
25 | |
26 if (uval > PNG_UINT_31_MAX) | |
27 png_error(png_ptr, "PNG unsigned integer out of range"); | |
28 | |
29 return (uval); | |
30 } | |
31 | |
32 #if defined(PNG_READ_gAMA_SUPPORTED) || defined(PNG_READ_cHRM_SUPPORTED) | |
33 /* The following is a variation on the above for use with the fixed | |
34 * point values used for gAMA and cHRM. Instead of png_error it | |
35 * issues a warning and returns (-1) - an invalid value because both | |
36 * gAMA and cHRM use *unsigned* integers for fixed point values. | |
37 */ | |
38 #define PNG_FIXED_ERROR (-1) | |
39 | |
40 static png_fixed_point /* PRIVATE */ | |
41 png_get_fixed_point(png_structrp png_ptr, png_const_bytep buf) | |
42 { | |
43 png_uint_32 uval = png_get_uint_32(buf); | |
44 | |
45 if (uval <= PNG_UINT_31_MAX) | |
46 return (png_fixed_point)uval; /* known to be in range */ | |
47 | |
48 /* The caller can turn off the warning by passing NULL. */ | |
49 if (png_ptr != NULL) | |
50 png_warning(png_ptr, "PNG fixed point integer out of range"); | |
51 | |
52 return PNG_FIXED_ERROR; | |
53 } | |
54 #endif | |
55 | |
56 #ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED | |
57 /* NOTE: the read macros will obscure these definitions, so that if | |
58 * PNG_USE_READ_MACROS is set the library will not use them internally, | |
59 * but the APIs will still be available externally. | |
60 * | |
61 * The parentheses around "PNGAPI function_name" in the following three | |
62 * functions are necessary because they allow the macros to co-exist with | |
63 * these (unused but exported) functions. | |
64 */ | |
65 | |
66 /* Grab an unsigned 32-bit integer from a buffer in big-endian format. */ | |
67 png_uint_32 (PNGAPI | |
68 png_get_uint_32)(png_const_bytep buf) | |
69 { | |
70 png_uint_32 uval = | |
71 ((png_uint_32)(*(buf )) << 24) + | |
72 ((png_uint_32)(*(buf + 1)) << 16) + | |
73 ((png_uint_32)(*(buf + 2)) << 8) + | |
74 ((png_uint_32)(*(buf + 3)) ) ; | |
75 | |
76 return uval; | |
77 } | |
78 | |
79 /* Grab a signed 32-bit integer from a buffer in big-endian format. The | |
80 * data is stored in the PNG file in two's complement format and there | |
81 * is no guarantee that a 'png_int_32' is exactly 32 bits, therefore | |
82 * the following code does a two's complement to native conversion. | |
83 */ | |
84 png_int_32 (PNGAPI | |
85 png_get_int_32)(png_const_bytep buf) | |
86 { | |
87 png_uint_32 uval = png_get_uint_32(buf); | |
88 if ((uval & 0x80000000) == 0) /* non-negative */ | |
89 return uval; | |
90 | |
91 uval = (uval ^ 0xffffffff) + 1; /* 2's complement: -x = ~x+1 */ | |
92 if ((uval & 0x80000000) == 0) /* no overflow */ | |
93 return -(png_int_32)uval; | |
94 /* The following has to be safe; this function only gets called on PNG data | |
95 * and if we get here that data is invalid. 0 is the most safe value and | |
96 * if not then an attacker would surely just generate a PNG with 0 instead. | |
97 */ | |
98 return 0; | |
99 } | |
100 | |
101 /* Grab an unsigned 16-bit integer from a buffer in big-endian format. */ | |
102 png_uint_16 (PNGAPI | |
103 png_get_uint_16)(png_const_bytep buf) | |
104 { | |
105 /* ANSI-C requires an int value to accomodate at least 16 bits so this | |
106 * works and allows the compiler not to worry about possible narrowing | |
107 * on 32-bit systems. (Pre-ANSI systems did not make integers smaller | |
108 * than 16 bits either.) | |
109 */ | |
110 unsigned int val = | |
111 ((unsigned int)(*buf) << 8) + | |
112 ((unsigned int)(*(buf + 1))); | |
113 | |
114 return (png_uint_16)val; | |
115 } | |
116 | |
117 #endif /* READ_INT_FUNCTIONS */ | |
118 | |
119 /* Read and check the PNG file signature */ | |
120 void /* PRIVATE */ | |
121 png_read_sig(png_structrp png_ptr, png_inforp info_ptr) | |
122 { | |
123 png_size_t num_checked, num_to_check; | |
124 | |
125 /* Exit if the user application does not expect a signature. */ | |
126 if (png_ptr->sig_bytes >= 8) | |
127 return; | |
128 | |
129 num_checked = png_ptr->sig_bytes; | |
130 num_to_check = 8 - num_checked; | |
131 | |
132 #ifdef PNG_IO_STATE_SUPPORTED | |
133 png_ptr->io_state = PNG_IO_READING | PNG_IO_SIGNATURE; | |
134 #endif | |
135 | |
136 /* The signature must be serialized in a single I/O call. */ | |
137 png_read_data(png_ptr, &(info_ptr->signature[num_checked]), num_to_check); | |
138 png_ptr->sig_bytes = 8; | |
139 | |
140 if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check) != 0) | |
141 { | |
142 if (num_checked < 4 && | |
143 png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4)) | |
144 png_error(png_ptr, "Not a PNG file"); | |
145 else | |
146 png_error(png_ptr, "PNG file corrupted by ASCII conversion"); | |
147 } | |
148 if (num_checked < 3) | |
149 png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE; | |
150 } | |
151 | |
152 /* Read the chunk header (length + type name). | |
153 * Put the type name into png_ptr->chunk_name, and return the length. | |
154 */ | |
155 png_uint_32 /* PRIVATE */ | |
156 png_read_chunk_header(png_structrp png_ptr) | |
157 { | |
158 png_byte buf[8]; | |
159 png_uint_32 length; | |
160 | |
161 #ifdef PNG_IO_STATE_SUPPORTED | |
162 png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_HDR; | |
163 #endif | |
164 | |
165 /* Read the length and the chunk name. | |
166 * This must be performed in a single I/O call. | |
167 */ | |
168 png_read_data(png_ptr, buf, 8); | |
169 length = png_get_uint_31(png_ptr, buf); | |
170 | |
171 /* Put the chunk name into png_ptr->chunk_name. */ | |
172 png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(buf+4); | |
173 | |
174 png_debug2(0, "Reading %lx chunk, length = %lu", | |
175 (unsigned long)png_ptr->chunk_name, (unsigned long)length); | |
176 | |
177 /* Reset the crc and run it over the chunk name. */ | |
178 png_reset_crc(png_ptr); | |
179 png_calculate_crc(png_ptr, buf + 4, 4); | |
180 | |
181 /* Check to see if chunk name is valid. */ | |
182 png_check_chunk_name(png_ptr, png_ptr->chunk_name); | |
183 | |
184 #ifdef PNG_IO_STATE_SUPPORTED | |
185 png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_DATA; | |
186 #endif | |
187 | |
188 return length; | |
189 } | |
190 | |
191 /* Read data, and (optionally) run it through the CRC. */ | |
192 void /* PRIVATE */ | |
193 png_crc_read(png_structrp png_ptr, png_bytep buf, png_uint_32 length) | |
194 { | |
195 if (png_ptr == NULL) | |
196 return; | |
197 | |
198 png_read_data(png_ptr, buf, length); | |
199 png_calculate_crc(png_ptr, buf, length); | |
200 } | |
201 | |
202 /* Optionally skip data and then check the CRC. Depending on whether we | |
203 * are reading an ancillary or critical chunk, and how the program has set | |
204 * things up, we may calculate the CRC on the data and print a message. | |
205 * Returns '1' if there was a CRC error, '0' otherwise. | |
206 */ | |
207 int /* PRIVATE */ | |
208 png_crc_finish(png_structrp png_ptr, png_uint_32 skip) | |
209 { | |
210 /* The size of the local buffer for inflate is a good guess as to a | |
211 * reasonable size to use for buffering reads from the application. | |
212 */ | |
213 while (skip > 0) | |
214 { | |
215 png_uint_32 len; | |
216 png_byte tmpbuf[PNG_INFLATE_BUF_SIZE]; | |
217 | |
218 len = (sizeof tmpbuf); | |
219 if (len > skip) | |
220 len = skip; | |
221 skip -= len; | |
222 | |
223 png_crc_read(png_ptr, tmpbuf, len); | |
224 } | |
225 | |
226 if (png_crc_error(png_ptr) != 0) | |
227 { | |
228 if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name) != 0 ? | |
229 (png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) == 0 : | |
230 (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_USE) != 0) | |
231 { | |
232 png_chunk_warning(png_ptr, "CRC error"); | |
233 } | |
234 | |
235 else | |
236 png_chunk_error(png_ptr, "CRC error"); | |
237 | |
238 return (1); | |
239 } | |
240 | |
241 return (0); | |
242 } | |
243 | |
244 /* Compare the CRC stored in the PNG file with that calculated by libpng from | |
245 * the data it has read thus far. | |
246 */ | |
247 int /* PRIVATE */ | |
248 png_crc_error(png_structrp png_ptr) | |
249 { | |
250 png_byte crc_bytes[4]; | |
251 png_uint_32 crc; | |
252 int need_crc = 1; | |
253 | |
254 if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name) != 0) | |
255 { | |
256 if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) == | |
257 (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN)) | |
258 need_crc = 0; | |
259 } | |
260 | |
261 else /* critical */ | |
262 { | |
263 if ((png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE) != 0) | |
264 need_crc = 0; | |
265 } | |
266 | |
267 #ifdef PNG_IO_STATE_SUPPORTED | |
268 png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_CRC; | |
269 #endif | |
270 | |
271 /* The chunk CRC must be serialized in a single I/O call. */ | |
272 png_read_data(png_ptr, crc_bytes, 4); | |
273 | |
274 if (need_crc != 0) | |
275 { | |
276 crc = png_get_uint_32(crc_bytes); | |
277 return ((int)(crc != png_ptr->crc)); | |
278 } | |
279 | |
280 else | |
281 return (0); | |
282 } | |
283 | |
284 #if defined(PNG_READ_iCCP_SUPPORTED) || defined(PNG_READ_iTXt_SUPPORTED) ||\ | |
285 defined(PNG_READ_pCAL_SUPPORTED) || defined(PNG_READ_sCAL_SUPPORTED) ||\ | |
286 defined(PNG_READ_sPLT_SUPPORTED) || defined(PNG_READ_tEXt_SUPPORTED) ||\ | |
287 defined(PNG_READ_zTXt_SUPPORTED) || defined(PNG_SEQUENTIAL_READ_SUPPORTED) | |
288 /* Manage the read buffer; this simply reallocates the buffer if it is not small | |
289 * enough (or if it is not allocated). The routine returns a pointer to the | |
290 * buffer; if an error occurs and 'warn' is set the routine returns NULL, else | |
291 * it will call png_error (via png_malloc) on failure. (warn == 2 means | |
292 * 'silent'). | |
293 */ | |
294 static png_bytep | |
295 png_read_buffer(png_structrp png_ptr, png_alloc_size_t new_size, int warn) | |
296 { | |
297 png_bytep buffer = png_ptr->read_buffer; | |
298 | |
299 if (buffer != NULL && new_size > png_ptr->read_buffer_size) | |
300 { | |
301 png_ptr->read_buffer = NULL; | |
302 png_ptr->read_buffer = NULL; | |
303 png_ptr->read_buffer_size = 0; | |
304 png_free(png_ptr, buffer); | |
305 buffer = NULL; | |
306 } | |
307 | |
308 if (buffer == NULL) | |
309 { | |
310 buffer = png_voidcast(png_bytep, png_malloc_base(png_ptr, new_size)); | |
311 | |
312 if (buffer != NULL) | |
313 { | |
314 png_ptr->read_buffer = buffer; | |
315 png_ptr->read_buffer_size = new_size; | |
316 } | |
317 | |
318 else if (warn < 2) /* else silent */ | |
319 { | |
320 if (warn != 0) | |
321 png_chunk_warning(png_ptr, "insufficient memory to read chunk"); | |
322 | |
323 else | |
324 png_chunk_error(png_ptr, "insufficient memory to read chunk"); | |
325 } | |
326 } | |
327 | |
328 return buffer; | |
329 } | |
330 #endif /* READ_iCCP|iTXt|pCAL|sCAL|sPLT|tEXt|zTXt|SEQUENTIAL_READ */ | |
331 | |
332 /* png_inflate_claim: claim the zstream for some nefarious purpose that involves | |
333 * decompression. Returns Z_OK on success, else a zlib error code. It checks | |
334 * the owner but, in final release builds, just issues a warning if some other | |
335 * chunk apparently owns the stream. Prior to release it does a png_error. | |
336 */ | |
337 static int | |
338 png_inflate_claim(png_structrp png_ptr, png_uint_32 owner) | |
339 { | |
340 if (png_ptr->zowner != 0) | |
341 { | |
342 char msg[64]; | |
343 | |
344 PNG_STRING_FROM_CHUNK(msg, png_ptr->zowner); | |
345 /* So the message that results is "<chunk> using zstream"; this is an | |
346 * internal error, but is very useful for debugging. i18n requirements | |
347 * are minimal. | |
348 */ | |
349 (void)png_safecat(msg, (sizeof msg), 4, " using zstream"); | |
350 #if PNG_RELEASE_BUILD | |
351 png_chunk_warning(png_ptr, msg); | |
352 png_ptr->zowner = 0; | |
353 #else | |
354 png_chunk_error(png_ptr, msg); | |
355 #endif | |
356 } | |
357 | |
358 /* Implementation note: unlike 'png_deflate_claim' this internal function | |
359 * does not take the size of the data as an argument. Some efficiency could | |
360 * be gained by using this when it is known *if* the zlib stream itself does | |
361 * not record the number; however, this is an illusion: the original writer | |
362 * of the PNG may have selected a lower window size, and we really must | |
363 * follow that because, for systems with with limited capabilities, we | |
364 * would otherwise reject the application's attempts to use a smaller window | |
365 * size (zlib doesn't have an interface to say "this or lower"!). | |
366 * | |
367 * inflateReset2 was added to zlib 1.2.4; before this the window could not be | |
368 * reset, therefore it is necessary to always allocate the maximum window | |
369 * size with earlier zlibs just in case later compressed chunks need it. | |
370 */ | |
371 { | |
372 int ret; /* zlib return code */ | |
373 #if PNG_ZLIB_VERNUM >= 0x1240 | |
374 | |
375 # if defined(PNG_SET_OPTION_SUPPORTED) && defined(PNG_MAXIMUM_INFLATE_WINDOW) | |
376 int window_bits; | |
377 | |
378 if (((png_ptr->options >> PNG_MAXIMUM_INFLATE_WINDOW) & 3) == | |
379 PNG_OPTION_ON) | |
380 { | |
381 window_bits = 15; | |
382 png_ptr->zstream_start = 0; /* fixed window size */ | |
383 } | |
384 | |
385 else | |
386 { | |
387 window_bits = 0; | |
388 png_ptr->zstream_start = 1; | |
389 } | |
390 # else | |
391 # define window_bits 0 | |
392 # endif | |
393 #endif | |
394 | |
395 /* Set this for safety, just in case the previous owner left pointers to | |
396 * memory allocations. | |
397 */ | |
398 png_ptr->zstream.next_in = NULL; | |
399 png_ptr->zstream.avail_in = 0; | |
400 png_ptr->zstream.next_out = NULL; | |
401 png_ptr->zstream.avail_out = 0; | |
402 | |
403 if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0) | |
404 { | |
405 #if PNG_ZLIB_VERNUM < 0x1240 | |
406 ret = inflateReset(&png_ptr->zstream); | |
407 #else | |
408 ret = inflateReset2(&png_ptr->zstream, window_bits); | |
409 #endif | |
410 } | |
411 | |
412 else | |
413 { | |
414 #if PNG_ZLIB_VERNUM < 0x1240 | |
415 ret = inflateInit(&png_ptr->zstream); | |
416 #else | |
417 ret = inflateInit2(&png_ptr->zstream, window_bits); | |
418 #endif | |
419 | |
420 if (ret == Z_OK) | |
421 png_ptr->flags |= PNG_FLAG_ZSTREAM_INITIALIZED; | |
422 } | |
423 | |
424 if (ret == Z_OK) | |
425 png_ptr->zowner = owner; | |
426 | |
427 else | |
428 png_zstream_error(png_ptr, ret); | |
429 | |
430 return ret; | |
431 } | |
432 | |
433 #ifdef window_bits | |
434 # undef window_bits | |
435 #endif | |
436 } | |
437 | |
438 #if PNG_ZLIB_VERNUM >= 0x1240 | |
439 /* Handle the start of the inflate stream if we called inflateInit2(strm,0); | |
440 * in this case some zlib versions skip validation of the CINFO field and, in | |
441 * certain circumstances, libpng may end up displaying an invalid image, in | |
442 * contrast to implementations that call zlib in the normal way (e.g. libpng | |
443 * 1.5). | |
444 */ | |
445 int /* PRIVATE */ | |
446 png_zlib_inflate(png_structrp png_ptr, int flush) | |
447 { | |
448 if (png_ptr->zstream_start && png_ptr->zstream.avail_in > 0) | |
449 { | |
450 if ((*png_ptr->zstream.next_in >> 4) > 7) | |
451 { | |
452 png_ptr->zstream.msg = "invalid window size (libpng)"; | |
453 return Z_DATA_ERROR; | |
454 } | |
455 | |
456 png_ptr->zstream_start = 0; | |
457 } | |
458 | |
459 return inflate(&png_ptr->zstream, flush); | |
460 } | |
461 #endif /* Zlib >= 1.2.4 */ | |
462 | |
463 #ifdef PNG_READ_COMPRESSED_TEXT_SUPPORTED | |
464 /* png_inflate now returns zlib error codes including Z_OK and Z_STREAM_END to | |
465 * allow the caller to do multiple calls if required. If the 'finish' flag is | |
466 * set Z_FINISH will be passed to the final inflate() call and Z_STREAM_END must | |
467 * be returned or there has been a problem, otherwise Z_SYNC_FLUSH is used and | |
468 * Z_OK or Z_STREAM_END will be returned on success. | |
469 * | |
470 * The input and output sizes are updated to the actual amounts of data consumed | |
471 * or written, not the amount available (as in a z_stream). The data pointers | |
472 * are not changed, so the next input is (data+input_size) and the next | |
473 * available output is (output+output_size). | |
474 */ | |
475 static int | |
476 png_inflate(png_structrp png_ptr, png_uint_32 owner, int finish, | |
477 /* INPUT: */ png_const_bytep input, png_uint_32p input_size_ptr, | |
478 /* OUTPUT: */ png_bytep output, png_alloc_size_t *output_size_ptr) | |
479 { | |
480 if (png_ptr->zowner == owner) /* Else not claimed */ | |
481 { | |
482 int ret; | |
483 png_alloc_size_t avail_out = *output_size_ptr; | |
484 png_uint_32 avail_in = *input_size_ptr; | |
485 | |
486 /* zlib can't necessarily handle more than 65535 bytes at once (i.e. it | |
487 * can't even necessarily handle 65536 bytes) because the type uInt is | |
488 * "16 bits or more". Consequently it is necessary to chunk the input to | |
489 * zlib. This code uses ZLIB_IO_MAX, from pngpriv.h, as the maximum (the | |
490 * maximum value that can be stored in a uInt.) It is possible to set | |
491 * ZLIB_IO_MAX to a lower value in pngpriv.h and this may sometimes have | |
492 * a performance advantage, because it reduces the amount of data accessed | |
493 * at each step and that may give the OS more time to page it in. | |
494 */ | |
495 png_ptr->zstream.next_in = PNGZ_INPUT_CAST(input); | |
496 /* avail_in and avail_out are set below from 'size' */ | |
497 png_ptr->zstream.avail_in = 0; | |
498 png_ptr->zstream.avail_out = 0; | |
499 | |
500 /* Read directly into the output if it is available (this is set to | |
501 * a local buffer below if output is NULL). | |
502 */ | |
503 if (output != NULL) | |
504 png_ptr->zstream.next_out = output; | |
505 | |
506 do | |
507 { | |
508 uInt avail; | |
509 Byte local_buffer[PNG_INFLATE_BUF_SIZE]; | |
510 | |
511 /* zlib INPUT BUFFER */ | |
512 /* The setting of 'avail_in' used to be outside the loop; by setting it | |
513 * inside it is possible to chunk the input to zlib and simply rely on | |
514 * zlib to advance the 'next_in' pointer. This allows arbitrary | |
515 * amounts of data to be passed through zlib at the unavoidable cost of | |
516 * requiring a window save (memcpy of up to 32768 output bytes) | |
517 * every ZLIB_IO_MAX input bytes. | |
518 */ | |
519 avail_in += png_ptr->zstream.avail_in; /* not consumed last time */ | |
520 | |
521 avail = ZLIB_IO_MAX; | |
522 | |
523 if (avail_in < avail) | |
524 avail = (uInt)avail_in; /* safe: < than ZLIB_IO_MAX */ | |
525 | |
526 avail_in -= avail; | |
527 png_ptr->zstream.avail_in = avail; | |
528 | |
529 /* zlib OUTPUT BUFFER */ | |
530 avail_out += png_ptr->zstream.avail_out; /* not written last time */ | |
531 | |
532 avail = ZLIB_IO_MAX; /* maximum zlib can process */ | |
533 | |
534 if (output == NULL) | |
535 { | |
536 /* Reset the output buffer each time round if output is NULL and | |
537 * make available the full buffer, up to 'remaining_space' | |
538 */ | |
539 png_ptr->zstream.next_out = local_buffer; | |
540 if ((sizeof local_buffer) < avail) | |
541 avail = (sizeof local_buffer); | |
542 } | |
543 | |
544 if (avail_out < avail) | |
545 avail = (uInt)avail_out; /* safe: < ZLIB_IO_MAX */ | |
546 | |
547 png_ptr->zstream.avail_out = avail; | |
548 avail_out -= avail; | |
549 | |
550 /* zlib inflate call */ | |
551 /* In fact 'avail_out' may be 0 at this point, that happens at the end | |
552 * of the read when the final LZ end code was not passed at the end of | |
553 * the previous chunk of input data. Tell zlib if we have reached the | |
554 * end of the output buffer. | |
555 */ | |
556 ret = PNG_INFLATE(png_ptr, avail_out > 0 ? Z_NO_FLUSH : | |
557 (finish ? Z_FINISH : Z_SYNC_FLUSH)); | |
558 } while (ret == Z_OK); | |
559 | |
560 /* For safety kill the local buffer pointer now */ | |
561 if (output == NULL) | |
562 png_ptr->zstream.next_out = NULL; | |
563 | |
564 /* Claw back the 'size' and 'remaining_space' byte counts. */ | |
565 avail_in += png_ptr->zstream.avail_in; | |
566 avail_out += png_ptr->zstream.avail_out; | |
567 | |
568 /* Update the input and output sizes; the updated values are the amount | |
569 * consumed or written, effectively the inverse of what zlib uses. | |
570 */ | |
571 if (avail_out > 0) | |
572 *output_size_ptr -= avail_out; | |
573 | |
574 if (avail_in > 0) | |
575 *input_size_ptr -= avail_in; | |
576 | |
577 /* Ensure png_ptr->zstream.msg is set (even in the success case!) */ | |
578 png_zstream_error(png_ptr, ret); | |
579 return ret; | |
580 } | |
581 | |
582 else | |
583 { | |
584 /* This is a bad internal error. The recovery assigns to the zstream msg | |
585 * pointer, which is not owned by the caller, but this is safe; it's only | |
586 * used on errors! | |
587 */ | |
588 png_ptr->zstream.msg = PNGZ_MSG_CAST("zstream unclaimed"); | |
589 return Z_STREAM_ERROR; | |
590 } | |
591 } | |
592 | |
593 /* | |
594 * Decompress trailing data in a chunk. The assumption is that read_buffer | |
595 * points at an allocated area holding the contents of a chunk with a | |
596 * trailing compressed part. What we get back is an allocated area | |
597 * holding the original prefix part and an uncompressed version of the | |
598 * trailing part (the malloc area passed in is freed). | |
599 */ | |
600 static int | |
601 png_decompress_chunk(png_structrp png_ptr, | |
602 png_uint_32 chunklength, png_uint_32 prefix_size, | |
603 png_alloc_size_t *newlength /* must be initialized to the maximum! */, | |
604 int terminate /*add a '\0' to the end of the uncompressed data*/) | |
605 { | |
606 /* TODO: implement different limits for different types of chunk. | |
607 * | |
608 * The caller supplies *newlength set to the maximum length of the | |
609 * uncompressed data, but this routine allocates space for the prefix and | |
610 * maybe a '\0' terminator too. We have to assume that 'prefix_size' is | |
611 * limited only by the maximum chunk size. | |
612 */ | |
613 png_alloc_size_t limit = PNG_SIZE_MAX; | |
614 | |
615 # ifdef PNG_SET_USER_LIMITS_SUPPORTED | |
616 if (png_ptr->user_chunk_malloc_max > 0 && | |
617 png_ptr->user_chunk_malloc_max < limit) | |
618 limit = png_ptr->user_chunk_malloc_max; | |
619 # elif PNG_USER_CHUNK_MALLOC_MAX > 0 | |
620 if (PNG_USER_CHUNK_MALLOC_MAX < limit) | |
621 limit = PNG_USER_CHUNK_MALLOC_MAX; | |
622 # endif | |
623 | |
624 if (limit >= prefix_size + (terminate != 0)) | |
625 { | |
626 int ret; | |
627 | |
628 limit -= prefix_size + (terminate != 0); | |
629 | |
630 if (limit < *newlength) | |
631 *newlength = limit; | |
632 | |
633 /* Now try to claim the stream. */ | |
634 ret = png_inflate_claim(png_ptr, png_ptr->chunk_name); | |
635 | |
636 if (ret == Z_OK) | |
637 { | |
638 png_uint_32 lzsize = chunklength - prefix_size; | |
639 | |
640 ret = png_inflate(png_ptr, png_ptr->chunk_name, 1/*finish*/, | |
641 /* input: */ png_ptr->read_buffer + prefix_size, &lzsize, | |
642 /* output: */ NULL, newlength); | |
643 | |
644 if (ret == Z_STREAM_END) | |
645 { | |
646 /* Use 'inflateReset' here, not 'inflateReset2' because this | |
647 * preserves the previously decided window size (otherwise it would | |
648 * be necessary to store the previous window size.) In practice | |
649 * this doesn't matter anyway, because png_inflate will call inflate | |
650 * with Z_FINISH in almost all cases, so the window will not be | |
651 * maintained. | |
652 */ | |
653 if (inflateReset(&png_ptr->zstream) == Z_OK) | |
654 { | |
655 /* Because of the limit checks above we know that the new, | |
656 * expanded, size will fit in a size_t (let alone an | |
657 * png_alloc_size_t). Use png_malloc_base here to avoid an | |
658 * extra OOM message. | |
659 */ | |
660 png_alloc_size_t new_size = *newlength; | |
661 png_alloc_size_t buffer_size = prefix_size + new_size + | |
662 (terminate != 0); | |
663 png_bytep text = png_voidcast(png_bytep, png_malloc_base(png_ptr, | |
664 buffer_size)); | |
665 | |
666 if (text != NULL) | |
667 { | |
668 ret = png_inflate(png_ptr, png_ptr->chunk_name, 1/*finish*/, | |
669 png_ptr->read_buffer + prefix_size, &lzsize, | |
670 text + prefix_size, newlength); | |
671 | |
672 if (ret == Z_STREAM_END) | |
673 { | |
674 if (new_size == *newlength) | |
675 { | |
676 if (terminate != 0) | |
677 text[prefix_size + *newlength] = 0; | |
678 | |
679 if (prefix_size > 0) | |
680 memcpy(text, png_ptr->read_buffer, prefix_size); | |
681 | |
682 { | |
683 png_bytep old_ptr = png_ptr->read_buffer; | |
684 | |
685 png_ptr->read_buffer = text; | |
686 png_ptr->read_buffer_size = buffer_size; | |
687 text = old_ptr; /* freed below */ | |
688 } | |
689 } | |
690 | |
691 else | |
692 { | |
693 /* The size changed on the second read, there can be no | |
694 * guarantee that anything is correct at this point. | |
695 * The 'msg' pointer has been set to "unexpected end of | |
696 * LZ stream", which is fine, but return an error code | |
697 * that the caller won't accept. | |
698 */ | |
699 ret = PNG_UNEXPECTED_ZLIB_RETURN; | |
700 } | |
701 } | |
702 | |
703 else if (ret == Z_OK) | |
704 ret = PNG_UNEXPECTED_ZLIB_RETURN; /* for safety */ | |
705 | |
706 /* Free the text pointer (this is the old read_buffer on | |
707 * success) | |
708 */ | |
709 png_free(png_ptr, text); | |
710 | |
711 /* This really is very benign, but it's still an error because | |
712 * the extra space may otherwise be used as a Trojan Horse. | |
713 */ | |
714 if (ret == Z_STREAM_END && | |
715 chunklength - prefix_size != lzsize) | |
716 png_chunk_benign_error(png_ptr, "extra compressed data"); | |
717 } | |
718 | |
719 else | |
720 { | |
721 /* Out of memory allocating the buffer */ | |
722 ret = Z_MEM_ERROR; | |
723 png_zstream_error(png_ptr, Z_MEM_ERROR); | |
724 } | |
725 } | |
726 | |
727 else | |
728 { | |
729 /* inflateReset failed, store the error message */ | |
730 png_zstream_error(png_ptr, ret); | |
731 | |
732 if (ret == Z_STREAM_END) | |
733 ret = PNG_UNEXPECTED_ZLIB_RETURN; | |
734 } | |
735 } | |
736 | |
737 else if (ret == Z_OK) | |
738 ret = PNG_UNEXPECTED_ZLIB_RETURN; | |
739 | |
740 /* Release the claimed stream */ | |
741 png_ptr->zowner = 0; | |
742 } | |
743 | |
744 else /* the claim failed */ if (ret == Z_STREAM_END) /* impossible! */ | |
745 ret = PNG_UNEXPECTED_ZLIB_RETURN; | |
746 | |
747 return ret; | |
748 } | |
749 | |
750 else | |
751 { | |
752 /* Application/configuration limits exceeded */ | |
753 png_zstream_error(png_ptr, Z_MEM_ERROR); | |
754 return Z_MEM_ERROR; | |
755 } | |
756 } | |
757 #endif /* READ_COMPRESSED_TEXT */ | |
758 | |
759 #ifdef PNG_READ_iCCP_SUPPORTED | |
760 /* Perform a partial read and decompress, producing 'avail_out' bytes and | |
761 * reading from the current chunk as required. | |
762 */ | |
763 static int | |
764 png_inflate_read(png_structrp png_ptr, png_bytep read_buffer, uInt read_size, | |
765 png_uint_32p chunk_bytes, png_bytep next_out, png_alloc_size_t *out_size, | |
766 int finish) | |
767 { | |
768 if (png_ptr->zowner == png_ptr->chunk_name) | |
769 { | |
770 int ret; | |
771 | |
772 /* next_in and avail_in must have been initialized by the caller. */ | |
773 png_ptr->zstream.next_out = next_out; | |
774 png_ptr->zstream.avail_out = 0; /* set in the loop */ | |
775 | |
776 do | |
777 { | |
778 if (png_ptr->zstream.avail_in == 0) | |
779 { | |
780 if (read_size > *chunk_bytes) | |
781 read_size = (uInt)*chunk_bytes; | |
782 *chunk_bytes -= read_size; | |
783 | |
784 if (read_size > 0) | |
785 png_crc_read(png_ptr, read_buffer, read_size); | |
786 | |
787 png_ptr->zstream.next_in = read_buffer; | |
788 png_ptr->zstream.avail_in = read_size; | |
789 } | |
790 | |
791 if (png_ptr->zstream.avail_out == 0) | |
792 { | |
793 uInt avail = ZLIB_IO_MAX; | |
794 if (avail > *out_size) | |
795 avail = (uInt)*out_size; | |
796 *out_size -= avail; | |
797 | |
798 png_ptr->zstream.avail_out = avail; | |
799 } | |
800 | |
801 /* Use Z_SYNC_FLUSH when there is no more chunk data to ensure that all | |
802 * the available output is produced; this allows reading of truncated | |
803 * streams. | |
804 */ | |
805 ret = PNG_INFLATE(png_ptr, | |
806 *chunk_bytes > 0 ? Z_NO_FLUSH : (finish ? Z_FINISH : Z_SYNC_FLUSH)); | |
807 } | |
808 while (ret == Z_OK && (*out_size > 0 || png_ptr->zstream.avail_out > 0)); | |
809 | |
810 *out_size += png_ptr->zstream.avail_out; | |
811 png_ptr->zstream.avail_out = 0; /* Should not be required, but is safe */ | |
812 | |
813 /* Ensure the error message pointer is always set: */ | |
814 png_zstream_error(png_ptr, ret); | |
815 return ret; | |
816 } | |
817 | |
818 else | |
819 { | |
820 png_ptr->zstream.msg = PNGZ_MSG_CAST("zstream unclaimed"); | |
821 return Z_STREAM_ERROR; | |
822 } | |
823 } | |
824 #endif | |
825 | |
826 /* Read and check the IDHR chunk */ | |
827 | |
828 void /* PRIVATE */ | |
829 png_handle_IHDR(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) | |
830 { | |
831 png_byte buf[13]; | |
832 png_uint_32 width, height; | |
833 int bit_depth, color_type, compression_type, filter_type; | |
834 int interlace_type; | |
835 | |
836 png_debug(1, "in png_handle_IHDR"); | |
837 | |
838 if ((png_ptr->mode & PNG_HAVE_IHDR) != 0) | |
839 png_chunk_error(png_ptr, "out of place"); | |
840 | |
841 /* Check the length */ | |
842 if (length != 13) | |
843 png_chunk_error(png_ptr, "invalid"); | |
844 | |
845 png_ptr->mode |= PNG_HAVE_IHDR; | |
846 | |
847 png_crc_read(png_ptr, buf, 13); | |
848 png_crc_finish(png_ptr, 0); | |
849 | |
850 width = png_get_uint_31(png_ptr, buf); | |
851 height = png_get_uint_31(png_ptr, buf + 4); | |
852 bit_depth = buf[8]; | |
853 color_type = buf[9]; | |
854 compression_type = buf[10]; | |
855 filter_type = buf[11]; | |
856 interlace_type = buf[12]; | |
857 | |
858 /* Set internal variables */ | |
859 png_ptr->width = width; | |
860 png_ptr->height = height; | |
861 png_ptr->bit_depth = (png_byte)bit_depth; | |
862 png_ptr->interlaced = (png_byte)interlace_type; | |
863 png_ptr->color_type = (png_byte)color_type; | |
864 #ifdef PNG_MNG_FEATURES_SUPPORTED | |
865 png_ptr->filter_type = (png_byte)filter_type; | |
866 #endif | |
867 png_ptr->compression_type = (png_byte)compression_type; | |
868 | |
869 /* Find number of channels */ | |
870 switch (png_ptr->color_type) | |
871 { | |
872 default: /* invalid, png_set_IHDR calls png_error */ | |
873 case PNG_COLOR_TYPE_GRAY: | |
874 case PNG_COLOR_TYPE_PALETTE: | |
875 png_ptr->channels = 1; | |
876 break; | |
877 | |
878 case PNG_COLOR_TYPE_RGB: | |
879 png_ptr->channels = 3; | |
880 break; | |
881 | |
882 case PNG_COLOR_TYPE_GRAY_ALPHA: | |
883 png_ptr->channels = 2; | |
884 break; | |
885 | |
886 case PNG_COLOR_TYPE_RGB_ALPHA: | |
887 png_ptr->channels = 4; | |
888 break; | |
889 } | |
890 | |
891 /* Set up other useful info */ | |
892 png_ptr->pixel_depth = (png_byte)(png_ptr->bit_depth * png_ptr->channels); | |
893 png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->width); | |
894 png_debug1(3, "bit_depth = %d", png_ptr->bit_depth); | |
895 png_debug1(3, "channels = %d", png_ptr->channels); | |
896 png_debug1(3, "rowbytes = %lu", (unsigned long)png_ptr->rowbytes); | |
897 png_set_IHDR(png_ptr, info_ptr, width, height, bit_depth, | |
898 color_type, interlace_type, compression_type, filter_type); | |
899 } | |
900 | |
901 /* Read and check the palette */ | |
902 void /* PRIVATE */ | |
903 png_handle_PLTE(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) | |
904 { | |
905 png_color palette[PNG_MAX_PALETTE_LENGTH]; | |
906 int max_palette_length, num, i; | |
907 #ifdef PNG_POINTER_INDEXING_SUPPORTED | |
908 png_colorp pal_ptr; | |
909 #endif | |
910 | |
911 png_debug(1, "in png_handle_PLTE"); | |
912 | |
913 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) | |
914 png_chunk_error(png_ptr, "missing IHDR"); | |
915 | |
916 /* Moved to before the 'after IDAT' check below because otherwise duplicate | |
917 * PLTE chunks are potentially ignored (the spec says there shall not be more | |
918 * than one PLTE, the error is not treated as benign, so this check trumps | |
919 * the requirement that PLTE appears before IDAT.) | |
920 */ | |
921 else if ((png_ptr->mode & PNG_HAVE_PLTE) != 0) | |
922 png_chunk_error(png_ptr, "duplicate"); | |
923 | |
924 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) | |
925 { | |
926 /* This is benign because the non-benign error happened before, when an | |
927 * IDAT was encountered in a color-mapped image with no PLTE. | |
928 */ | |
929 png_crc_finish(png_ptr, length); | |
930 png_chunk_benign_error(png_ptr, "out of place"); | |
931 return; | |
932 } | |
933 | |
934 png_ptr->mode |= PNG_HAVE_PLTE; | |
935 | |
936 if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0) | |
937 { | |
938 png_crc_finish(png_ptr, length); | |
939 png_chunk_benign_error(png_ptr, "ignored in grayscale PNG"); | |
940 return; | |
941 } | |
942 | |
943 #ifndef PNG_READ_OPT_PLTE_SUPPORTED | |
944 if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE) | |
945 { | |
946 png_crc_finish(png_ptr, length); | |
947 return; | |
948 } | |
949 #endif | |
950 | |
951 if (length > 3*PNG_MAX_PALETTE_LENGTH || length % 3) | |
952 { | |
953 png_crc_finish(png_ptr, length); | |
954 | |
955 if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE) | |
956 png_chunk_benign_error(png_ptr, "invalid"); | |
957 | |
958 else | |
959 png_chunk_error(png_ptr, "invalid"); | |
960 | |
961 return; | |
962 } | |
963 | |
964 /* The cast is safe because 'length' is less than 3*PNG_MAX_PALETTE_LENGTH */ | |
965 num = (int)length / 3; | |
966 | |
967 /* If the palette has 256 or fewer entries but is too large for the bit | |
968 * depth, we don't issue an error, to preserve the behavior of previous | |
969 * libpng versions. We silently truncate the unused extra palette entries | |
970 * here. | |
971 */ | |
972 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) | |
973 max_palette_length = (1 << png_ptr->bit_depth); | |
974 else | |
975 max_palette_length = PNG_MAX_PALETTE_LENGTH; | |
976 | |
977 if (num > max_palette_length) | |
978 num = max_palette_length; | |
979 | |
980 #ifdef PNG_POINTER_INDEXING_SUPPORTED | |
981 for (i = 0, pal_ptr = palette; i < num; i++, pal_ptr++) | |
982 { | |
983 png_byte buf[3]; | |
984 | |
985 png_crc_read(png_ptr, buf, 3); | |
986 pal_ptr->red = buf[0]; | |
987 pal_ptr->green = buf[1]; | |
988 pal_ptr->blue = buf[2]; | |
989 } | |
990 #else | |
991 for (i = 0; i < num; i++) | |
992 { | |
993 png_byte buf[3]; | |
994 | |
995 png_crc_read(png_ptr, buf, 3); | |
996 /* Don't depend upon png_color being any order */ | |
997 palette[i].red = buf[0]; | |
998 palette[i].green = buf[1]; | |
999 palette[i].blue = buf[2]; | |
1000 } | |
1001 #endif | |
1002 | |
1003 /* If we actually need the PLTE chunk (ie for a paletted image), we do | |
1004 * whatever the normal CRC configuration tells us. However, if we | |
1005 * have an RGB image, the PLTE can be considered ancillary, so | |
1006 * we will act as though it is. | |
1007 */ | |
1008 #ifndef PNG_READ_OPT_PLTE_SUPPORTED | |
1009 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) | |
1010 #endif | |
1011 { | |
1012 png_crc_finish(png_ptr, (int) length - num * 3); | |
1013 } | |
1014 | |
1015 #ifndef PNG_READ_OPT_PLTE_SUPPORTED | |
1016 else if (png_crc_error(png_ptr) != 0) /* Only if we have a CRC error */ | |
1017 { | |
1018 /* If we don't want to use the data from an ancillary chunk, | |
1019 * we have two options: an error abort, or a warning and we | |
1020 * ignore the data in this chunk (which should be OK, since | |
1021 * it's considered ancillary for a RGB or RGBA image). | |
1022 * | |
1023 * IMPLEMENTATION NOTE: this is only here because png_crc_finish uses the | |
1024 * chunk type to determine whether to check the ancillary or the critical | |
1025 * flags. | |
1026 */ | |
1027 if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_USE) == 0) | |
1028 { | |
1029 if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) != 0) | |
1030 return; | |
1031 | |
1032 else | |
1033 png_chunk_error(png_ptr, "CRC error"); | |
1034 } | |
1035 | |
1036 /* Otherwise, we (optionally) emit a warning and use the chunk. */ | |
1037 else if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) == 0) | |
1038 png_chunk_warning(png_ptr, "CRC error"); | |
1039 } | |
1040 #endif | |
1041 | |
1042 /* TODO: png_set_PLTE has the side effect of setting png_ptr->palette to its | |
1043 * own copy of the palette. This has the side effect that when png_start_row | |
1044 * is called (this happens after any call to png_read_update_info) the | |
1045 * info_ptr palette gets changed. This is extremely unexpected and | |
1046 * confusing. | |
1047 * | |
1048 * Fix this by not sharing the palette in this way. | |
1049 */ | |
1050 png_set_PLTE(png_ptr, info_ptr, palette, num); | |
1051 | |
1052 /* The three chunks, bKGD, hIST and tRNS *must* appear after PLTE and before | |
1053 * IDAT. Prior to 1.6.0 this was not checked; instead the code merely | |
1054 * checked the apparent validity of a tRNS chunk inserted before PLTE on a | |
1055 * palette PNG. 1.6.0 attempts to rigorously follow the standard and | |
1056 * therefore does a benign error if the erroneous condition is detected *and* | |
1057 * cancels the tRNS if the benign error returns. The alternative is to | |
1058 * amend the standard since it would be rather hypocritical of the standards | |
1059 * maintainers to ignore it. | |
1060 */ | |
1061 #ifdef PNG_READ_tRNS_SUPPORTED | |
1062 if (png_ptr->num_trans > 0 || | |
1063 (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS) != 0)) | |
1064 { | |
1065 /* Cancel this because otherwise it would be used if the transforms | |
1066 * require it. Don't cancel the 'valid' flag because this would prevent | |
1067 * detection of duplicate chunks. | |
1068 */ | |
1069 png_ptr->num_trans = 0; | |
1070 | |
1071 if (info_ptr != NULL) | |
1072 info_ptr->num_trans = 0; | |
1073 | |
1074 png_chunk_benign_error(png_ptr, "tRNS must be after"); | |
1075 } | |
1076 #endif | |
1077 | |
1078 #ifdef PNG_READ_hIST_SUPPORTED | |
1079 if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST) != 0) | |
1080 png_chunk_benign_error(png_ptr, "hIST must be after"); | |
1081 #endif | |
1082 | |
1083 #ifdef PNG_READ_bKGD_SUPPORTED | |
1084 if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD) != 0) | |
1085 png_chunk_benign_error(png_ptr, "bKGD must be after"); | |
1086 #endif | |
1087 } | |
1088 | |
1089 void /* PRIVATE */ | |
1090 png_handle_IEND(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) | |
1091 { | |
1092 png_debug(1, "in png_handle_IEND"); | |
1093 | |
1094 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0 || | |
1095 (png_ptr->mode & PNG_HAVE_IDAT) == 0) | |
1096 png_chunk_error(png_ptr, "out of place"); | |
1097 | |
1098 png_ptr->mode |= (PNG_AFTER_IDAT | PNG_HAVE_IEND); | |
1099 | |
1100 png_crc_finish(png_ptr, length); | |
1101 | |
1102 if (length != 0) | |
1103 png_chunk_benign_error(png_ptr, "invalid"); | |
1104 | |
1105 PNG_UNUSED(info_ptr) | |
1106 } | |
1107 | |
1108 #ifdef PNG_READ_gAMA_SUPPORTED | |
1109 void /* PRIVATE */ | |
1110 png_handle_gAMA(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) | |
1111 { | |
1112 png_fixed_point igamma; | |
1113 png_byte buf[4]; | |
1114 | |
1115 png_debug(1, "in png_handle_gAMA"); | |
1116 | |
1117 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) | |
1118 png_chunk_error(png_ptr, "missing IHDR"); | |
1119 | |
1120 else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0) | |
1121 { | |
1122 png_crc_finish(png_ptr, length); | |
1123 png_chunk_benign_error(png_ptr, "out of place"); | |
1124 return; | |
1125 } | |
1126 | |
1127 if (length != 4) | |
1128 { | |
1129 png_crc_finish(png_ptr, length); | |
1130 png_chunk_benign_error(png_ptr, "invalid"); | |
1131 return; | |
1132 } | |
1133 | |
1134 png_crc_read(png_ptr, buf, 4); | |
1135 | |
1136 if (png_crc_finish(png_ptr, 0) != 0) | |
1137 return; | |
1138 | |
1139 igamma = png_get_fixed_point(NULL, buf); | |
1140 | |
1141 png_colorspace_set_gamma(png_ptr, &png_ptr->colorspace, igamma); | |
1142 png_colorspace_sync(png_ptr, info_ptr); | |
1143 } | |
1144 #endif | |
1145 | |
1146 #ifdef PNG_READ_sBIT_SUPPORTED | |
1147 void /* PRIVATE */ | |
1148 png_handle_sBIT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) | |
1149 { | |
1150 unsigned int truelen, i; | |
1151 png_byte sample_depth; | |
1152 png_byte buf[4]; | |
1153 | |
1154 png_debug(1, "in png_handle_sBIT"); | |
1155 | |
1156 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) | |
1157 png_chunk_error(png_ptr, "missing IHDR"); | |
1158 | |
1159 else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0) | |
1160 { | |
1161 png_crc_finish(png_ptr, length); | |
1162 png_chunk_benign_error(png_ptr, "out of place"); | |
1163 return; | |
1164 } | |
1165 | |
1166 if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sBIT) != 0) | |
1167 { | |
1168 png_crc_finish(png_ptr, length); | |
1169 png_chunk_benign_error(png_ptr, "duplicate"); | |
1170 return; | |
1171 } | |
1172 | |
1173 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) | |
1174 { | |
1175 truelen = 3; | |
1176 sample_depth = 8; | |
1177 } | |
1178 | |
1179 else | |
1180 { | |
1181 truelen = png_ptr->channels; | |
1182 sample_depth = png_ptr->bit_depth; | |
1183 } | |
1184 | |
1185 if (length != truelen || length > 4) | |
1186 { | |
1187 png_chunk_benign_error(png_ptr, "invalid"); | |
1188 png_crc_finish(png_ptr, length); | |
1189 return; | |
1190 } | |
1191 | |
1192 buf[0] = buf[1] = buf[2] = buf[3] = sample_depth; | |
1193 png_crc_read(png_ptr, buf, truelen); | |
1194 | |
1195 if (png_crc_finish(png_ptr, 0) != 0) | |
1196 return; | |
1197 | |
1198 for (i=0; i<truelen; ++i) | |
1199 { | |
1200 if (buf[i] == 0 || buf[i] > sample_depth) | |
1201 { | |
1202 png_chunk_benign_error(png_ptr, "invalid"); | |
1203 return; | |
1204 } | |
1205 } | |
1206 | |
1207 if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0) | |
1208 { | |
1209 png_ptr->sig_bit.red = buf[0]; | |
1210 png_ptr->sig_bit.green = buf[1]; | |
1211 png_ptr->sig_bit.blue = buf[2]; | |
1212 png_ptr->sig_bit.alpha = buf[3]; | |
1213 } | |
1214 | |
1215 else | |
1216 { | |
1217 png_ptr->sig_bit.gray = buf[0]; | |
1218 png_ptr->sig_bit.red = buf[0]; | |
1219 png_ptr->sig_bit.green = buf[0]; | |
1220 png_ptr->sig_bit.blue = buf[0]; | |
1221 png_ptr->sig_bit.alpha = buf[1]; | |
1222 } | |
1223 | |
1224 png_set_sBIT(png_ptr, info_ptr, &(png_ptr->sig_bit)); | |
1225 } | |
1226 #endif | |
1227 | |
1228 #ifdef PNG_READ_cHRM_SUPPORTED | |
1229 void /* PRIVATE */ | |
1230 png_handle_cHRM(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) | |
1231 { | |
1232 png_byte buf[32]; | |
1233 png_xy xy; | |
1234 | |
1235 png_debug(1, "in png_handle_cHRM"); | |
1236 | |
1237 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) | |
1238 png_chunk_error(png_ptr, "missing IHDR"); | |
1239 | |
1240 else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0) | |
1241 { | |
1242 png_crc_finish(png_ptr, length); | |
1243 png_chunk_benign_error(png_ptr, "out of place"); | |
1244 return; | |
1245 } | |
1246 | |
1247 if (length != 32) | |
1248 { | |
1249 png_crc_finish(png_ptr, length); | |
1250 png_chunk_benign_error(png_ptr, "invalid"); | |
1251 return; | |
1252 } | |
1253 | |
1254 png_crc_read(png_ptr, buf, 32); | |
1255 | |
1256 if (png_crc_finish(png_ptr, 0) != 0) | |
1257 return; | |
1258 | |
1259 xy.whitex = png_get_fixed_point(NULL, buf); | |
1260 xy.whitey = png_get_fixed_point(NULL, buf + 4); | |
1261 xy.redx = png_get_fixed_point(NULL, buf + 8); | |
1262 xy.redy = png_get_fixed_point(NULL, buf + 12); | |
1263 xy.greenx = png_get_fixed_point(NULL, buf + 16); | |
1264 xy.greeny = png_get_fixed_point(NULL, buf + 20); | |
1265 xy.bluex = png_get_fixed_point(NULL, buf + 24); | |
1266 xy.bluey = png_get_fixed_point(NULL, buf + 28); | |
1267 | |
1268 if (xy.whitex == PNG_FIXED_ERROR || | |
1269 xy.whitey == PNG_FIXED_ERROR || | |
1270 xy.redx == PNG_FIXED_ERROR || | |
1271 xy.redy == PNG_FIXED_ERROR || | |
1272 xy.greenx == PNG_FIXED_ERROR || | |
1273 xy.greeny == PNG_FIXED_ERROR || | |
1274 xy.bluex == PNG_FIXED_ERROR || | |
1275 xy.bluey == PNG_FIXED_ERROR) | |
1276 { | |
1277 png_chunk_benign_error(png_ptr, "invalid values"); | |
1278 return; | |
1279 } | |
1280 | |
1281 /* If a colorspace error has already been output skip this chunk */ | |
1282 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0) | |
1283 return; | |
1284 | |
1285 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_FROM_cHRM) != 0) | |
1286 { | |
1287 png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID; | |
1288 png_colorspace_sync(png_ptr, info_ptr); | |
1289 png_chunk_benign_error(png_ptr, "duplicate"); | |
1290 return; | |
1291 } | |
1292 | |
1293 png_ptr->colorspace.flags |= PNG_COLORSPACE_FROM_cHRM; | |
1294 (void)png_colorspace_set_chromaticities(png_ptr, &png_ptr->colorspace, &xy, | |
1295 1/*prefer cHRM values*/); | |
1296 png_colorspace_sync(png_ptr, info_ptr); | |
1297 } | |
1298 #endif | |
1299 | |
1300 #ifdef PNG_READ_sRGB_SUPPORTED | |
1301 void /* PRIVATE */ | |
1302 png_handle_sRGB(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) | |
1303 { | |
1304 png_byte intent; | |
1305 | |
1306 png_debug(1, "in png_handle_sRGB"); | |
1307 | |
1308 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) | |
1309 png_chunk_error(png_ptr, "missing IHDR"); | |
1310 | |
1311 else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0) | |
1312 { | |
1313 png_crc_finish(png_ptr, length); | |
1314 png_chunk_benign_error(png_ptr, "out of place"); | |
1315 return; | |
1316 } | |
1317 | |
1318 if (length != 1) | |
1319 { | |
1320 png_crc_finish(png_ptr, length); | |
1321 png_chunk_benign_error(png_ptr, "invalid"); | |
1322 return; | |
1323 } | |
1324 | |
1325 png_crc_read(png_ptr, &intent, 1); | |
1326 | |
1327 if (png_crc_finish(png_ptr, 0) != 0) | |
1328 return; | |
1329 | |
1330 /* If a colorspace error has already been output skip this chunk */ | |
1331 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0) | |
1332 return; | |
1333 | |
1334 /* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect | |
1335 * this. | |
1336 */ | |
1337 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_INTENT) != 0) | |
1338 { | |
1339 png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID; | |
1340 png_colorspace_sync(png_ptr, info_ptr); | |
1341 png_chunk_benign_error(png_ptr, "too many profiles"); | |
1342 return; | |
1343 } | |
1344 | |
1345 (void)png_colorspace_set_sRGB(png_ptr, &png_ptr->colorspace, intent); | |
1346 png_colorspace_sync(png_ptr, info_ptr); | |
1347 } | |
1348 #endif /* READ_sRGB */ | |
1349 | |
1350 #ifdef PNG_READ_iCCP_SUPPORTED | |
1351 void /* PRIVATE */ | |
1352 png_handle_iCCP(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) | |
1353 /* Note: this does not properly handle profiles that are > 64K under DOS */ | |
1354 { | |
1355 png_const_charp errmsg = NULL; /* error message output, or no error */ | |
1356 int finished = 0; /* crc checked */ | |
1357 | |
1358 png_debug(1, "in png_handle_iCCP"); | |
1359 | |
1360 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) | |
1361 png_chunk_error(png_ptr, "missing IHDR"); | |
1362 | |
1363 else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0) | |
1364 { | |
1365 png_crc_finish(png_ptr, length); | |
1366 png_chunk_benign_error(png_ptr, "out of place"); | |
1367 return; | |
1368 } | |
1369 | |
1370 /* Consistent with all the above colorspace handling an obviously *invalid* | |
1371 * chunk is just ignored, so does not invalidate the color space. An | |
1372 * alternative is to set the 'invalid' flags at the start of this routine | |
1373 * and only clear them in they were not set before and all the tests pass. | |
1374 * The minimum 'deflate' stream is assumed to be just the 2 byte header and | |
1375 * 4 byte checksum. The keyword must be at least one character and there is | |
1376 * a terminator (0) byte and the compression method. | |
1377 */ | |
1378 if (length < 9) | |
1379 { | |
1380 png_crc_finish(png_ptr, length); | |
1381 png_chunk_benign_error(png_ptr, "too short"); | |
1382 return; | |
1383 } | |
1384 | |
1385 /* If a colorspace error has already been output skip this chunk */ | |
1386 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0) | |
1387 { | |
1388 png_crc_finish(png_ptr, length); | |
1389 return; | |
1390 } | |
1391 | |
1392 /* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect | |
1393 * this. | |
1394 */ | |
1395 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_INTENT) == 0) | |
1396 { | |
1397 uInt read_length, keyword_length; | |
1398 char keyword[81]; | |
1399 | |
1400 /* Find the keyword; the keyword plus separator and compression method | |
1401 * bytes can be at most 81 characters long. | |
1402 */ | |
1403 read_length = 81; /* maximum */ | |
1404 if (read_length > length) | |
1405 read_length = (uInt)length; | |
1406 | |
1407 png_crc_read(png_ptr, (png_bytep)keyword, read_length); | |
1408 length -= read_length; | |
1409 | |
1410 keyword_length = 0; | |
1411 while (keyword_length < 80 && keyword_length < read_length && | |
1412 keyword[keyword_length] != 0) | |
1413 ++keyword_length; | |
1414 | |
1415 /* TODO: make the keyword checking common */ | |
1416 if (keyword_length >= 1 && keyword_length <= 79) | |
1417 { | |
1418 /* We only understand '0' compression - deflate - so if we get a | |
1419 * different value we can't safely decode the chunk. | |
1420 */ | |
1421 if (keyword_length+1 < read_length && | |
1422 keyword[keyword_length+1] == PNG_COMPRESSION_TYPE_BASE) | |
1423 { | |
1424 read_length -= keyword_length+2; | |
1425 | |
1426 if (png_inflate_claim(png_ptr, png_iCCP) == Z_OK) | |
1427 { | |
1428 Byte profile_header[132]; | |
1429 Byte local_buffer[PNG_INFLATE_BUF_SIZE]; | |
1430 png_alloc_size_t size = (sizeof profile_header); | |
1431 | |
1432 png_ptr->zstream.next_in = (Bytef*)keyword + (keyword_length+2); | |
1433 png_ptr->zstream.avail_in = read_length; | |
1434 (void)png_inflate_read(png_ptr, local_buffer, | |
1435 (sizeof local_buffer), &length, profile_header, &size, | |
1436 0/*finish: don't, because the output is too small*/); | |
1437 | |
1438 if (size == 0) | |
1439 { | |
1440 /* We have the ICC profile header; do the basic header checks. | |
1441 */ | |
1442 const png_uint_32 profile_length = | |
1443 png_get_uint_32(profile_header); | |
1444 | |
1445 if (png_icc_check_length(png_ptr, &png_ptr->colorspace, | |
1446 keyword, profile_length) != 0) | |
1447 { | |
1448 /* The length is apparently ok, so we can check the 132 | |
1449 * byte header. | |
1450 */ | |
1451 if (png_icc_check_header(png_ptr, &png_ptr->colorspace, | |
1452 keyword, profile_length, profile_header, | |
1453 png_ptr->color_type) != 0) | |
1454 { | |
1455 /* Now read the tag table; a variable size buffer is | |
1456 * needed at this point, allocate one for the whole | |
1457 * profile. The header check has already validated | |
1458 * that none of these stuff will overflow. | |
1459 */ | |
1460 const png_uint_32 tag_count = png_get_uint_32( | |
1461 profile_header+128); | |
1462 png_bytep profile = png_read_buffer(png_ptr, | |
1463 profile_length, 2/*silent*/); | |
1464 | |
1465 if (profile != NULL) | |
1466 { | |
1467 memcpy(profile, profile_header, | |
1468 (sizeof profile_header)); | |
1469 | |
1470 size = 12 * tag_count; | |
1471 | |
1472 (void)png_inflate_read(png_ptr, local_buffer, | |
1473 (sizeof local_buffer), &length, | |
1474 profile + (sizeof profile_header), &size, 0); | |
1475 | |
1476 /* Still expect a buffer error because we expect | |
1477 * there to be some tag data! | |
1478 */ | |
1479 if (size == 0) | |
1480 { | |
1481 if (png_icc_check_tag_table(png_ptr, | |
1482 &png_ptr->colorspace, keyword, profile_length, | |
1483 profile) != 0) | |
1484 { | |
1485 /* The profile has been validated for basic | |
1486 * security issues, so read the whole thing in. | |
1487 */ | |
1488 size = profile_length - (sizeof profile_header) | |
1489 - 12 * tag_count; | |
1490 | |
1491 (void)png_inflate_read(png_ptr, local_buffer, | |
1492 (sizeof local_buffer), &length, | |
1493 profile + (sizeof profile_header) + | |
1494 12 * tag_count, &size, 1/*finish*/); | |
1495 | |
1496 if (length > 0 && !(png_ptr->flags & | |
1497 PNG_FLAG_BENIGN_ERRORS_WARN)) | |
1498 errmsg = "extra compressed data"; | |
1499 | |
1500 /* But otherwise allow extra data: */ | |
1501 else if (size == 0) | |
1502 { | |
1503 if (length > 0) | |
1504 { | |
1505 /* This can be handled completely, so | |
1506 * keep going. | |
1507 */ | |
1508 png_chunk_warning(png_ptr, | |
1509 "extra compressed data"); | |
1510 } | |
1511 | |
1512 png_crc_finish(png_ptr, length); | |
1513 finished = 1; | |
1514 | |
1515 # ifdef PNG_sRGB_SUPPORTED | |
1516 /* Check for a match against sRGB */ | |
1517 png_icc_set_sRGB(png_ptr, | |
1518 &png_ptr->colorspace, profile, | |
1519 png_ptr->zstream.adler); | |
1520 # endif | |
1521 | |
1522 /* Steal the profile for info_ptr. */ | |
1523 if (info_ptr != NULL) | |
1524 { | |
1525 png_free_data(png_ptr, info_ptr, | |
1526 PNG_FREE_ICCP, 0); | |
1527 | |
1528 info_ptr->iccp_name = png_voidcast(char*, | |
1529 png_malloc_base(png_ptr, | |
1530 keyword_length+1)); | |
1531 if (info_ptr->iccp_name != NULL) | |
1532 { | |
1533 memcpy(info_ptr->iccp_name, keyword, | |
1534 keyword_length+1); | |
1535 info_ptr->iccp_proflen = | |
1536 profile_length; | |
1537 info_ptr->iccp_profile = profile; | |
1538 png_ptr->read_buffer = NULL; /*steal*/ | |
1539 info_ptr->free_me |= PNG_FREE_ICCP; | |
1540 info_ptr->valid |= PNG_INFO_iCCP; | |
1541 } | |
1542 | |
1543 else | |
1544 { | |
1545 png_ptr->colorspace.flags |= | |
1546 PNG_COLORSPACE_INVALID; | |
1547 errmsg = "out of memory"; | |
1548 } | |
1549 } | |
1550 | |
1551 /* else the profile remains in the read | |
1552 * buffer which gets reused for subsequent | |
1553 * chunks. | |
1554 */ | |
1555 | |
1556 if (info_ptr != NULL) | |
1557 png_colorspace_sync(png_ptr, info_ptr); | |
1558 | |
1559 if (errmsg == NULL) | |
1560 { | |
1561 png_ptr->zowner = 0; | |
1562 return; | |
1563 } | |
1564 } | |
1565 | |
1566 else if (size > 0) | |
1567 errmsg = "truncated"; | |
1568 | |
1569 #ifndef __COVERITY__ | |
1570 else | |
1571 errmsg = png_ptr->zstream.msg; | |
1572 #endif | |
1573 } | |
1574 | |
1575 /* else png_icc_check_tag_table output an error */ | |
1576 } | |
1577 | |
1578 else /* profile truncated */ | |
1579 errmsg = png_ptr->zstream.msg; | |
1580 } | |
1581 | |
1582 else | |
1583 errmsg = "out of memory"; | |
1584 } | |
1585 | |
1586 /* else png_icc_check_header output an error */ | |
1587 } | |
1588 | |
1589 /* else png_icc_check_length output an error */ | |
1590 } | |
1591 | |
1592 else /* profile truncated */ | |
1593 errmsg = png_ptr->zstream.msg; | |
1594 | |
1595 /* Release the stream */ | |
1596 png_ptr->zowner = 0; | |
1597 } | |
1598 | |
1599 else /* png_inflate_claim failed */ | |
1600 errmsg = png_ptr->zstream.msg; | |
1601 } | |
1602 | |
1603 else | |
1604 errmsg = "bad compression method"; /* or missing */ | |
1605 } | |
1606 | |
1607 else | |
1608 errmsg = "bad keyword"; | |
1609 } | |
1610 | |
1611 else | |
1612 errmsg = "too many profiles"; | |
1613 | |
1614 /* Failure: the reason is in 'errmsg' */ | |
1615 if (finished == 0) | |
1616 png_crc_finish(png_ptr, length); | |
1617 | |
1618 png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID; | |
1619 png_colorspace_sync(png_ptr, info_ptr); | |
1620 if (errmsg != NULL) /* else already output */ | |
1621 png_chunk_benign_error(png_ptr, errmsg); | |
1622 } | |
1623 #endif /* READ_iCCP */ | |
1624 | |
1625 #ifdef PNG_READ_sPLT_SUPPORTED | |
1626 void /* PRIVATE */ | |
1627 png_handle_sPLT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) | |
1628 /* Note: this does not properly handle chunks that are > 64K under DOS */ | |
1629 { | |
1630 png_bytep entry_start, buffer; | |
1631 png_sPLT_t new_palette; | |
1632 png_sPLT_entryp pp; | |
1633 png_uint_32 data_length; | |
1634 int entry_size, i; | |
1635 png_uint_32 skip = 0; | |
1636 png_uint_32 dl; | |
1637 png_size_t max_dl; | |
1638 | |
1639 png_debug(1, "in png_handle_sPLT"); | |
1640 | |
1641 #ifdef PNG_USER_LIMITS_SUPPORTED | |
1642 if (png_ptr->user_chunk_cache_max != 0) | |
1643 { | |
1644 if (png_ptr->user_chunk_cache_max == 1) | |
1645 { | |
1646 png_crc_finish(png_ptr, length); | |
1647 return; | |
1648 } | |
1649 | |
1650 if (--png_ptr->user_chunk_cache_max == 1) | |
1651 { | |
1652 png_warning(png_ptr, "No space in chunk cache for sPLT"); | |
1653 png_crc_finish(png_ptr, length); | |
1654 return; | |
1655 } | |
1656 } | |
1657 #endif | |
1658 | |
1659 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) | |
1660 png_chunk_error(png_ptr, "missing IHDR"); | |
1661 | |
1662 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) | |
1663 { | |
1664 png_crc_finish(png_ptr, length); | |
1665 png_chunk_benign_error(png_ptr, "out of place"); | |
1666 return; | |
1667 } | |
1668 | |
1669 #ifdef PNG_MAX_MALLOC_64K | |
1670 if (length > 65535U) | |
1671 { | |
1672 png_crc_finish(png_ptr, length); | |
1673 png_chunk_benign_error(png_ptr, "too large to fit in memory"); | |
1674 return; | |
1675 } | |
1676 #endif | |
1677 | |
1678 buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/); | |
1679 if (buffer == NULL) | |
1680 { | |
1681 png_crc_finish(png_ptr, length); | |
1682 png_chunk_benign_error(png_ptr, "out of memory"); | |
1683 return; | |
1684 } | |
1685 | |
1686 | |
1687 /* WARNING: this may break if size_t is less than 32 bits; it is assumed | |
1688 * that the PNG_MAX_MALLOC_64K test is enabled in this case, but this is a | |
1689 * potential breakage point if the types in pngconf.h aren't exactly right. | |
1690 */ | |
1691 png_crc_read(png_ptr, buffer, length); | |
1692 | |
1693 if (png_crc_finish(png_ptr, skip) != 0) | |
1694 return; | |
1695 | |
1696 buffer[length] = 0; | |
1697 | |
1698 for (entry_start = buffer; *entry_start; entry_start++) | |
1699 /* Empty loop to find end of name */ ; | |
1700 | |
1701 ++entry_start; | |
1702 | |
1703 /* A sample depth should follow the separator, and we should be on it */ | |
1704 if (length < 2U || entry_start > buffer + (length - 2U)) | |
1705 { | |
1706 png_warning(png_ptr, "malformed sPLT chunk"); | |
1707 return; | |
1708 } | |
1709 | |
1710 new_palette.depth = *entry_start++; | |
1711 entry_size = (new_palette.depth == 8 ? 6 : 10); | |
1712 /* This must fit in a png_uint_32 because it is derived from the original | |
1713 * chunk data length. | |
1714 */ | |
1715 data_length = length - (png_uint_32)(entry_start - buffer); | |
1716 | |
1717 /* Integrity-check the data length */ | |
1718 if ((data_length % entry_size) != 0) | |
1719 { | |
1720 png_warning(png_ptr, "sPLT chunk has bad length"); | |
1721 return; | |
1722 } | |
1723 | |
1724 dl = (png_int_32)(data_length / entry_size); | |
1725 max_dl = PNG_SIZE_MAX / (sizeof (png_sPLT_entry)); | |
1726 | |
1727 if (dl > max_dl) | |
1728 { | |
1729 png_warning(png_ptr, "sPLT chunk too long"); | |
1730 return; | |
1731 } | |
1732 | |
1733 new_palette.nentries = (png_int_32)(data_length / entry_size); | |
1734 | |
1735 new_palette.entries = (png_sPLT_entryp)png_malloc_warn( | |
1736 png_ptr, new_palette.nentries * (sizeof (png_sPLT_entry))); | |
1737 | |
1738 if (new_palette.entries == NULL) | |
1739 { | |
1740 png_warning(png_ptr, "sPLT chunk requires too much memory"); | |
1741 return; | |
1742 } | |
1743 | |
1744 #ifdef PNG_POINTER_INDEXING_SUPPORTED | |
1745 for (i = 0; i < new_palette.nentries; i++) | |
1746 { | |
1747 pp = new_palette.entries + i; | |
1748 | |
1749 if (new_palette.depth == 8) | |
1750 { | |
1751 pp->red = *entry_start++; | |
1752 pp->green = *entry_start++; | |
1753 pp->blue = *entry_start++; | |
1754 pp->alpha = *entry_start++; | |
1755 } | |
1756 | |
1757 else | |
1758 { | |
1759 pp->red = png_get_uint_16(entry_start); entry_start += 2; | |
1760 pp->green = png_get_uint_16(entry_start); entry_start += 2; | |
1761 pp->blue = png_get_uint_16(entry_start); entry_start += 2; | |
1762 pp->alpha = png_get_uint_16(entry_start); entry_start += 2; | |
1763 } | |
1764 | |
1765 pp->frequency = png_get_uint_16(entry_start); entry_start += 2; | |
1766 } | |
1767 #else | |
1768 pp = new_palette.entries; | |
1769 | |
1770 for (i = 0; i < new_palette.nentries; i++) | |
1771 { | |
1772 | |
1773 if (new_palette.depth == 8) | |
1774 { | |
1775 pp[i].red = *entry_start++; | |
1776 pp[i].green = *entry_start++; | |
1777 pp[i].blue = *entry_start++; | |
1778 pp[i].alpha = *entry_start++; | |
1779 } | |
1780 | |
1781 else | |
1782 { | |
1783 pp[i].red = png_get_uint_16(entry_start); entry_start += 2; | |
1784 pp[i].green = png_get_uint_16(entry_start); entry_start += 2; | |
1785 pp[i].blue = png_get_uint_16(entry_start); entry_start += 2; | |
1786 pp[i].alpha = png_get_uint_16(entry_start); entry_start += 2; | |
1787 } | |
1788 | |
1789 pp[i].frequency = png_get_uint_16(entry_start); entry_start += 2; | |
1790 } | |
1791 #endif | |
1792 | |
1793 /* Discard all chunk data except the name and stash that */ | |
1794 new_palette.name = (png_charp)buffer; | |
1795 | |
1796 png_set_sPLT(png_ptr, info_ptr, &new_palette, 1); | |
1797 | |
1798 png_free(png_ptr, new_palette.entries); | |
1799 } | |
1800 #endif /* READ_sPLT */ | |
1801 | |
1802 #ifdef PNG_READ_tRNS_SUPPORTED | |
1803 void /* PRIVATE */ | |
1804 png_handle_tRNS(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) | |
1805 { | |
1806 png_byte readbuf[PNG_MAX_PALETTE_LENGTH]; | |
1807 | |
1808 png_debug(1, "in png_handle_tRNS"); | |
1809 | |
1810 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) | |
1811 png_chunk_error(png_ptr, "missing IHDR"); | |
1812 | |
1813 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) | |
1814 { | |
1815 png_crc_finish(png_ptr, length); | |
1816 png_chunk_benign_error(png_ptr, "out of place"); | |
1817 return; | |
1818 } | |
1819 | |
1820 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS) != 0) | |
1821 { | |
1822 png_crc_finish(png_ptr, length); | |
1823 png_chunk_benign_error(png_ptr, "duplicate"); | |
1824 return; | |
1825 } | |
1826 | |
1827 if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY) | |
1828 { | |
1829 png_byte buf[2]; | |
1830 | |
1831 if (length != 2) | |
1832 { | |
1833 png_crc_finish(png_ptr, length); | |
1834 png_chunk_benign_error(png_ptr, "invalid"); | |
1835 return; | |
1836 } | |
1837 | |
1838 png_crc_read(png_ptr, buf, 2); | |
1839 png_ptr->num_trans = 1; | |
1840 png_ptr->trans_color.gray = png_get_uint_16(buf); | |
1841 } | |
1842 | |
1843 else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB) | |
1844 { | |
1845 png_byte buf[6]; | |
1846 | |
1847 if (length != 6) | |
1848 { | |
1849 png_crc_finish(png_ptr, length); | |
1850 png_chunk_benign_error(png_ptr, "invalid"); | |
1851 return; | |
1852 } | |
1853 | |
1854 png_crc_read(png_ptr, buf, length); | |
1855 png_ptr->num_trans = 1; | |
1856 png_ptr->trans_color.red = png_get_uint_16(buf); | |
1857 png_ptr->trans_color.green = png_get_uint_16(buf + 2); | |
1858 png_ptr->trans_color.blue = png_get_uint_16(buf + 4); | |
1859 } | |
1860 | |
1861 else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) | |
1862 { | |
1863 if ((png_ptr->mode & PNG_HAVE_PLTE) == 0) | |
1864 { | |
1865 /* TODO: is this actually an error in the ISO spec? */ | |
1866 png_crc_finish(png_ptr, length); | |
1867 png_chunk_benign_error(png_ptr, "out of place"); | |
1868 return; | |
1869 } | |
1870 | |
1871 if (length > (unsigned int) png_ptr->num_palette || | |
1872 length > (unsigned int) PNG_MAX_PALETTE_LENGTH || | |
1873 length == 0) | |
1874 { | |
1875 png_crc_finish(png_ptr, length); | |
1876 png_chunk_benign_error(png_ptr, "invalid"); | |
1877 return; | |
1878 } | |
1879 | |
1880 png_crc_read(png_ptr, readbuf, length); | |
1881 png_ptr->num_trans = (png_uint_16)length; | |
1882 } | |
1883 | |
1884 else | |
1885 { | |
1886 png_crc_finish(png_ptr, length); | |
1887 png_chunk_benign_error(png_ptr, "invalid with alpha channel"); | |
1888 return; | |
1889 } | |
1890 | |
1891 if (png_crc_finish(png_ptr, 0) != 0) | |
1892 { | |
1893 png_ptr->num_trans = 0; | |
1894 return; | |
1895 } | |
1896 | |
1897 /* TODO: this is a horrible side effect in the palette case because the | |
1898 * png_struct ends up with a pointer to the tRNS buffer owned by the | |
1899 * png_info. Fix this. | |
1900 */ | |
1901 png_set_tRNS(png_ptr, info_ptr, readbuf, png_ptr->num_trans, | |
1902 &(png_ptr->trans_color)); | |
1903 } | |
1904 #endif | |
1905 | |
1906 #ifdef PNG_READ_bKGD_SUPPORTED | |
1907 void /* PRIVATE */ | |
1908 png_handle_bKGD(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) | |
1909 { | |
1910 unsigned int truelen; | |
1911 png_byte buf[6]; | |
1912 png_color_16 background; | |
1913 | |
1914 png_debug(1, "in png_handle_bKGD"); | |
1915 | |
1916 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) | |
1917 png_chunk_error(png_ptr, "missing IHDR"); | |
1918 | |
1919 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0 || | |
1920 (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE && | |
1921 (png_ptr->mode & PNG_HAVE_PLTE) == 0)) | |
1922 { | |
1923 png_crc_finish(png_ptr, length); | |
1924 png_chunk_benign_error(png_ptr, "out of place"); | |
1925 return; | |
1926 } | |
1927 | |
1928 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD) != 0) | |
1929 { | |
1930 png_crc_finish(png_ptr, length); | |
1931 png_chunk_benign_error(png_ptr, "duplicate"); | |
1932 return; | |
1933 } | |
1934 | |
1935 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) | |
1936 truelen = 1; | |
1937 | |
1938 else if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0) | |
1939 truelen = 6; | |
1940 | |
1941 else | |
1942 truelen = 2; | |
1943 | |
1944 if (length != truelen) | |
1945 { | |
1946 png_crc_finish(png_ptr, length); | |
1947 png_chunk_benign_error(png_ptr, "invalid"); | |
1948 return; | |
1949 } | |
1950 | |
1951 png_crc_read(png_ptr, buf, truelen); | |
1952 | |
1953 if (png_crc_finish(png_ptr, 0) != 0) | |
1954 return; | |
1955 | |
1956 /* We convert the index value into RGB components so that we can allow | |
1957 * arbitrary RGB values for background when we have transparency, and | |
1958 * so it is easy to determine the RGB values of the background color | |
1959 * from the info_ptr struct. | |
1960 */ | |
1961 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) | |
1962 { | |
1963 background.index = buf[0]; | |
1964 | |
1965 if (info_ptr != NULL && info_ptr->num_palette != 0) | |
1966 { | |
1967 if (buf[0] >= info_ptr->num_palette) | |
1968 { | |
1969 png_chunk_benign_error(png_ptr, "invalid index"); | |
1970 return; | |
1971 } | |
1972 | |
1973 background.red = (png_uint_16)png_ptr->palette[buf[0]].red; | |
1974 background.green = (png_uint_16)png_ptr->palette[buf[0]].green; | |
1975 background.blue = (png_uint_16)png_ptr->palette[buf[0]].blue; | |
1976 } | |
1977 | |
1978 else | |
1979 background.red = background.green = background.blue = 0; | |
1980 | |
1981 background.gray = 0; | |
1982 } | |
1983 | |
1984 else if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0) /* GRAY */ | |
1985 { | |
1986 background.index = 0; | |
1987 background.red = | |
1988 background.green = | |
1989 background.blue = | |
1990 background.gray = png_get_uint_16(buf); | |
1991 } | |
1992 | |
1993 else | |
1994 { | |
1995 background.index = 0; | |
1996 background.red = png_get_uint_16(buf); | |
1997 background.green = png_get_uint_16(buf + 2); | |
1998 background.blue = png_get_uint_16(buf + 4); | |
1999 background.gray = 0; | |
2000 } | |
2001 | |
2002 png_set_bKGD(png_ptr, info_ptr, &background); | |
2003 } | |
2004 #endif | |
2005 | |
2006 #ifdef PNG_READ_hIST_SUPPORTED | |
2007 void /* PRIVATE */ | |
2008 png_handle_hIST(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) | |
2009 { | |
2010 unsigned int num, i; | |
2011 png_uint_16 readbuf[PNG_MAX_PALETTE_LENGTH]; | |
2012 | |
2013 png_debug(1, "in png_handle_hIST"); | |
2014 | |
2015 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) | |
2016 png_chunk_error(png_ptr, "missing IHDR"); | |
2017 | |
2018 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0 || | |
2019 (png_ptr->mode & PNG_HAVE_PLTE) == 0) | |
2020 { | |
2021 png_crc_finish(png_ptr, length); | |
2022 png_chunk_benign_error(png_ptr, "out of place"); | |
2023 return; | |
2024 } | |
2025 | |
2026 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST) != 0) | |
2027 { | |
2028 png_crc_finish(png_ptr, length); | |
2029 png_chunk_benign_error(png_ptr, "duplicate"); | |
2030 return; | |
2031 } | |
2032 | |
2033 num = length / 2 ; | |
2034 | |
2035 if (num != (unsigned int) png_ptr->num_palette || | |
2036 num > (unsigned int) PNG_MAX_PALETTE_LENGTH) | |
2037 { | |
2038 png_crc_finish(png_ptr, length); | |
2039 png_chunk_benign_error(png_ptr, "invalid"); | |
2040 return; | |
2041 } | |
2042 | |
2043 for (i = 0; i < num; i++) | |
2044 { | |
2045 png_byte buf[2]; | |
2046 | |
2047 png_crc_read(png_ptr, buf, 2); | |
2048 readbuf[i] = png_get_uint_16(buf); | |
2049 } | |
2050 | |
2051 if (png_crc_finish(png_ptr, 0) != 0) | |
2052 return; | |
2053 | |
2054 png_set_hIST(png_ptr, info_ptr, readbuf); | |
2055 } | |
2056 #endif | |
2057 | |
2058 #ifdef PNG_READ_pHYs_SUPPORTED | |
2059 void /* PRIVATE */ | |
2060 png_handle_pHYs(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) | |
2061 { | |
2062 png_byte buf[9]; | |
2063 png_uint_32 res_x, res_y; | |
2064 int unit_type; | |
2065 | |
2066 png_debug(1, "in png_handle_pHYs"); | |
2067 | |
2068 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) | |
2069 png_chunk_error(png_ptr, "missing IHDR"); | |
2070 | |
2071 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) | |
2072 { | |
2073 png_crc_finish(png_ptr, length); | |
2074 png_chunk_benign_error(png_ptr, "out of place"); | |
2075 return; | |
2076 } | |
2077 | |
2078 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs) != 0) | |
2079 { | |
2080 png_crc_finish(png_ptr, length); | |
2081 png_chunk_benign_error(png_ptr, "duplicate"); | |
2082 return; | |
2083 } | |
2084 | |
2085 if (length != 9) | |
2086 { | |
2087 png_crc_finish(png_ptr, length); | |
2088 png_chunk_benign_error(png_ptr, "invalid"); | |
2089 return; | |
2090 } | |
2091 | |
2092 png_crc_read(png_ptr, buf, 9); | |
2093 | |
2094 if (png_crc_finish(png_ptr, 0) != 0) | |
2095 return; | |
2096 | |
2097 res_x = png_get_uint_32(buf); | |
2098 res_y = png_get_uint_32(buf + 4); | |
2099 unit_type = buf[8]; | |
2100 png_set_pHYs(png_ptr, info_ptr, res_x, res_y, unit_type); | |
2101 } | |
2102 #endif | |
2103 | |
2104 #ifdef PNG_READ_oFFs_SUPPORTED | |
2105 void /* PRIVATE */ | |
2106 png_handle_oFFs(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) | |
2107 { | |
2108 png_byte buf[9]; | |
2109 png_int_32 offset_x, offset_y; | |
2110 int unit_type; | |
2111 | |
2112 png_debug(1, "in png_handle_oFFs"); | |
2113 | |
2114 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) | |
2115 png_chunk_error(png_ptr, "missing IHDR"); | |
2116 | |
2117 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) | |
2118 { | |
2119 png_crc_finish(png_ptr, length); | |
2120 png_chunk_benign_error(png_ptr, "out of place"); | |
2121 return; | |
2122 } | |
2123 | |
2124 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs) != 0) | |
2125 { | |
2126 png_crc_finish(png_ptr, length); | |
2127 png_chunk_benign_error(png_ptr, "duplicate"); | |
2128 return; | |
2129 } | |
2130 | |
2131 if (length != 9) | |
2132 { | |
2133 png_crc_finish(png_ptr, length); | |
2134 png_chunk_benign_error(png_ptr, "invalid"); | |
2135 return; | |
2136 } | |
2137 | |
2138 png_crc_read(png_ptr, buf, 9); | |
2139 | |
2140 if (png_crc_finish(png_ptr, 0) != 0) | |
2141 return; | |
2142 | |
2143 offset_x = png_get_int_32(buf); | |
2144 offset_y = png_get_int_32(buf + 4); | |
2145 unit_type = buf[8]; | |
2146 png_set_oFFs(png_ptr, info_ptr, offset_x, offset_y, unit_type); | |
2147 } | |
2148 #endif | |
2149 | |
2150 #ifdef PNG_READ_pCAL_SUPPORTED | |
2151 /* Read the pCAL chunk (described in the PNG Extensions document) */ | |
2152 void /* PRIVATE */ | |
2153 png_handle_pCAL(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) | |
2154 { | |
2155 png_int_32 X0, X1; | |
2156 png_byte type, nparams; | |
2157 png_bytep buffer, buf, units, endptr; | |
2158 png_charpp params; | |
2159 int i; | |
2160 | |
2161 png_debug(1, "in png_handle_pCAL"); | |
2162 | |
2163 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) | |
2164 png_chunk_error(png_ptr, "missing IHDR"); | |
2165 | |
2166 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) | |
2167 { | |
2168 png_crc_finish(png_ptr, length); | |
2169 png_chunk_benign_error(png_ptr, "out of place"); | |
2170 return; | |
2171 } | |
2172 | |
2173 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pCAL) != 0) | |
2174 { | |
2175 png_crc_finish(png_ptr, length); | |
2176 png_chunk_benign_error(png_ptr, "duplicate"); | |
2177 return; | |
2178 } | |
2179 | |
2180 png_debug1(2, "Allocating and reading pCAL chunk data (%u bytes)", | |
2181 length + 1); | |
2182 | |
2183 buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/); | |
2184 | |
2185 if (buffer == NULL) | |
2186 { | |
2187 png_crc_finish(png_ptr, length); | |
2188 png_chunk_benign_error(png_ptr, "out of memory"); | |
2189 return; | |
2190 } | |
2191 | |
2192 png_crc_read(png_ptr, buffer, length); | |
2193 | |
2194 if (png_crc_finish(png_ptr, 0) != 0) | |
2195 return; | |
2196 | |
2197 buffer[length] = 0; /* Null terminate the last string */ | |
2198 | |
2199 png_debug(3, "Finding end of pCAL purpose string"); | |
2200 for (buf = buffer; *buf; buf++) | |
2201 /* Empty loop */ ; | |
2202 | |
2203 endptr = buffer + length; | |
2204 | |
2205 /* We need to have at least 12 bytes after the purpose string | |
2206 * in order to get the parameter information. | |
2207 */ | |
2208 if (endptr - buf <= 12) | |
2209 { | |
2210 png_chunk_benign_error(png_ptr, "invalid"); | |
2211 return; | |
2212 } | |
2213 | |
2214 png_debug(3, "Reading pCAL X0, X1, type, nparams, and units"); | |
2215 X0 = png_get_int_32((png_bytep)buf+1); | |
2216 X1 = png_get_int_32((png_bytep)buf+5); | |
2217 type = buf[9]; | |
2218 nparams = buf[10]; | |
2219 units = buf + 11; | |
2220 | |
2221 png_debug(3, "Checking pCAL equation type and number of parameters"); | |
2222 /* Check that we have the right number of parameters for known | |
2223 * equation types. | |
2224 */ | |
2225 if ((type == PNG_EQUATION_LINEAR && nparams != 2) || | |
2226 (type == PNG_EQUATION_BASE_E && nparams != 3) || | |
2227 (type == PNG_EQUATION_ARBITRARY && nparams != 3) || | |
2228 (type == PNG_EQUATION_HYPERBOLIC && nparams != 4)) | |
2229 { | |
2230 png_chunk_benign_error(png_ptr, "invalid parameter count"); | |
2231 return; | |
2232 } | |
2233 | |
2234 else if (type >= PNG_EQUATION_LAST) | |
2235 { | |
2236 png_chunk_benign_error(png_ptr, "unrecognized equation type"); | |
2237 } | |
2238 | |
2239 for (buf = units; *buf; buf++) | |
2240 /* Empty loop to move past the units string. */ ; | |
2241 | |
2242 png_debug(3, "Allocating pCAL parameters array"); | |
2243 | |
2244 params = png_voidcast(png_charpp, png_malloc_warn(png_ptr, | |
2245 nparams * (sizeof (png_charp)))); | |
2246 | |
2247 if (params == NULL) | |
2248 { | |
2249 png_chunk_benign_error(png_ptr, "out of memory"); | |
2250 return; | |
2251 } | |
2252 | |
2253 /* Get pointers to the start of each parameter string. */ | |
2254 for (i = 0; i < nparams; i++) | |
2255 { | |
2256 buf++; /* Skip the null string terminator from previous parameter. */ | |
2257 | |
2258 png_debug1(3, "Reading pCAL parameter %d", i); | |
2259 | |
2260 for (params[i] = (png_charp)buf; buf <= endptr && *buf != 0; buf++) | |
2261 /* Empty loop to move past each parameter string */ ; | |
2262 | |
2263 /* Make sure we haven't run out of data yet */ | |
2264 if (buf > endptr) | |
2265 { | |
2266 png_free(png_ptr, params); | |
2267 png_chunk_benign_error(png_ptr, "invalid data"); | |
2268 return; | |
2269 } | |
2270 } | |
2271 | |
2272 png_set_pCAL(png_ptr, info_ptr, (png_charp)buffer, X0, X1, type, nparams, | |
2273 (png_charp)units, params); | |
2274 | |
2275 png_free(png_ptr, params); | |
2276 } | |
2277 #endif | |
2278 | |
2279 #ifdef PNG_READ_sCAL_SUPPORTED | |
2280 /* Read the sCAL chunk */ | |
2281 void /* PRIVATE */ | |
2282 png_handle_sCAL(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) | |
2283 { | |
2284 png_bytep buffer; | |
2285 png_size_t i; | |
2286 int state; | |
2287 | |
2288 png_debug(1, "in png_handle_sCAL"); | |
2289 | |
2290 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) | |
2291 png_chunk_error(png_ptr, "missing IHDR"); | |
2292 | |
2293 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) | |
2294 { | |
2295 png_crc_finish(png_ptr, length); | |
2296 png_chunk_benign_error(png_ptr, "out of place"); | |
2297 return; | |
2298 } | |
2299 | |
2300 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sCAL) != 0) | |
2301 { | |
2302 png_crc_finish(png_ptr, length); | |
2303 png_chunk_benign_error(png_ptr, "duplicate"); | |
2304 return; | |
2305 } | |
2306 | |
2307 /* Need unit type, width, \0, height: minimum 4 bytes */ | |
2308 else if (length < 4) | |
2309 { | |
2310 png_crc_finish(png_ptr, length); | |
2311 png_chunk_benign_error(png_ptr, "invalid"); | |
2312 return; | |
2313 } | |
2314 | |
2315 png_debug1(2, "Allocating and reading sCAL chunk data (%u bytes)", | |
2316 length + 1); | |
2317 | |
2318 buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/); | |
2319 | |
2320 if (buffer == NULL) | |
2321 { | |
2322 png_chunk_benign_error(png_ptr, "out of memory"); | |
2323 png_crc_finish(png_ptr, length); | |
2324 return; | |
2325 } | |
2326 | |
2327 png_crc_read(png_ptr, buffer, length); | |
2328 buffer[length] = 0; /* Null terminate the last string */ | |
2329 | |
2330 if (png_crc_finish(png_ptr, 0) != 0) | |
2331 return; | |
2332 | |
2333 /* Validate the unit. */ | |
2334 if (buffer[0] != 1 && buffer[0] != 2) | |
2335 { | |
2336 png_chunk_benign_error(png_ptr, "invalid unit"); | |
2337 return; | |
2338 } | |
2339 | |
2340 /* Validate the ASCII numbers, need two ASCII numbers separated by | |
2341 * a '\0' and they need to fit exactly in the chunk data. | |
2342 */ | |
2343 i = 1; | |
2344 state = 0; | |
2345 | |
2346 if (png_check_fp_number((png_const_charp)buffer, length, &state, &i) == 0 || | |
2347 i >= length || buffer[i++] != 0) | |
2348 png_chunk_benign_error(png_ptr, "bad width format"); | |
2349 | |
2350 else if (PNG_FP_IS_POSITIVE(state) == 0) | |
2351 png_chunk_benign_error(png_ptr, "non-positive width"); | |
2352 | |
2353 else | |
2354 { | |
2355 png_size_t heighti = i; | |
2356 | |
2357 state = 0; | |
2358 if (png_check_fp_number((png_const_charp)buffer, length, | |
2359 &state, &i) == 0 || i != length) | |
2360 png_chunk_benign_error(png_ptr, "bad height format"); | |
2361 | |
2362 else if (PNG_FP_IS_POSITIVE(state) == 0) | |
2363 png_chunk_benign_error(png_ptr, "non-positive height"); | |
2364 | |
2365 else | |
2366 /* This is the (only) success case. */ | |
2367 png_set_sCAL_s(png_ptr, info_ptr, buffer[0], | |
2368 (png_charp)buffer+1, (png_charp)buffer+heighti); | |
2369 } | |
2370 } | |
2371 #endif | |
2372 | |
2373 #ifdef PNG_READ_tIME_SUPPORTED | |
2374 void /* PRIVATE */ | |
2375 png_handle_tIME(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) | |
2376 { | |
2377 png_byte buf[7]; | |
2378 png_time mod_time; | |
2379 | |
2380 png_debug(1, "in png_handle_tIME"); | |
2381 | |
2382 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) | |
2383 png_chunk_error(png_ptr, "missing IHDR"); | |
2384 | |
2385 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tIME) != 0) | |
2386 { | |
2387 png_crc_finish(png_ptr, length); | |
2388 png_chunk_benign_error(png_ptr, "duplicate"); | |
2389 return; | |
2390 } | |
2391 | |
2392 if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) | |
2393 png_ptr->mode |= PNG_AFTER_IDAT; | |
2394 | |
2395 if (length != 7) | |
2396 { | |
2397 png_crc_finish(png_ptr, length); | |
2398 png_chunk_benign_error(png_ptr, "invalid"); | |
2399 return; | |
2400 } | |
2401 | |
2402 png_crc_read(png_ptr, buf, 7); | |
2403 | |
2404 if (png_crc_finish(png_ptr, 0) != 0) | |
2405 return; | |
2406 | |
2407 mod_time.second = buf[6]; | |
2408 mod_time.minute = buf[5]; | |
2409 mod_time.hour = buf[4]; | |
2410 mod_time.day = buf[3]; | |
2411 mod_time.month = buf[2]; | |
2412 mod_time.year = png_get_uint_16(buf); | |
2413 | |
2414 png_set_tIME(png_ptr, info_ptr, &mod_time); | |
2415 } | |
2416 #endif | |
2417 | |
2418 #ifdef PNG_READ_tEXt_SUPPORTED | |
2419 /* Note: this does not properly handle chunks that are > 64K under DOS */ | |
2420 void /* PRIVATE */ | |
2421 png_handle_tEXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) | |
2422 { | |
2423 png_text text_info; | |
2424 png_bytep buffer; | |
2425 png_charp key; | |
2426 png_charp text; | |
2427 png_uint_32 skip = 0; | |
2428 | |
2429 png_debug(1, "in png_handle_tEXt"); | |
2430 | |
2431 #ifdef PNG_USER_LIMITS_SUPPORTED | |
2432 if (png_ptr->user_chunk_cache_max != 0) | |
2433 { | |
2434 if (png_ptr->user_chunk_cache_max == 1) | |
2435 { | |
2436 png_crc_finish(png_ptr, length); | |
2437 return; | |
2438 } | |
2439 | |
2440 if (--png_ptr->user_chunk_cache_max == 1) | |
2441 { | |
2442 png_crc_finish(png_ptr, length); | |
2443 png_chunk_benign_error(png_ptr, "no space in chunk cache"); | |
2444 return; | |
2445 } | |
2446 } | |
2447 #endif | |
2448 | |
2449 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) | |
2450 png_chunk_error(png_ptr, "missing IHDR"); | |
2451 | |
2452 if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) | |
2453 png_ptr->mode |= PNG_AFTER_IDAT; | |
2454 | |
2455 #ifdef PNG_MAX_MALLOC_64K | |
2456 if (length > 65535U) | |
2457 { | |
2458 png_crc_finish(png_ptr, length); | |
2459 png_chunk_benign_error(png_ptr, "too large to fit in memory"); | |
2460 return; | |
2461 } | |
2462 #endif | |
2463 | |
2464 buffer = png_read_buffer(png_ptr, length+1, 1/*warn*/); | |
2465 | |
2466 if (buffer == NULL) | |
2467 { | |
2468 png_chunk_benign_error(png_ptr, "out of memory"); | |
2469 return; | |
2470 } | |
2471 | |
2472 png_crc_read(png_ptr, buffer, length); | |
2473 | |
2474 if (png_crc_finish(png_ptr, skip) != 0) | |
2475 return; | |
2476 | |
2477 key = (png_charp)buffer; | |
2478 key[length] = 0; | |
2479 | |
2480 for (text = key; *text; text++) | |
2481 /* Empty loop to find end of key */ ; | |
2482 | |
2483 if (text != key + length) | |
2484 text++; | |
2485 | |
2486 text_info.compression = PNG_TEXT_COMPRESSION_NONE; | |
2487 text_info.key = key; | |
2488 text_info.lang = NULL; | |
2489 text_info.lang_key = NULL; | |
2490 text_info.itxt_length = 0; | |
2491 text_info.text = text; | |
2492 text_info.text_length = strlen(text); | |
2493 | |
2494 if (png_set_text_2(png_ptr, info_ptr, &text_info, 1) != 0) | |
2495 png_warning(png_ptr, "Insufficient memory to process text chunk"); | |
2496 } | |
2497 #endif | |
2498 | |
2499 #ifdef PNG_READ_zTXt_SUPPORTED | |
2500 /* Note: this does not correctly handle chunks that are > 64K under DOS */ | |
2501 void /* PRIVATE */ | |
2502 png_handle_zTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) | |
2503 { | |
2504 png_const_charp errmsg = NULL; | |
2505 png_bytep buffer; | |
2506 png_uint_32 keyword_length; | |
2507 | |
2508 png_debug(1, "in png_handle_zTXt"); | |
2509 | |
2510 #ifdef PNG_USER_LIMITS_SUPPORTED | |
2511 if (png_ptr->user_chunk_cache_max != 0) | |
2512 { | |
2513 if (png_ptr->user_chunk_cache_max == 1) | |
2514 { | |
2515 png_crc_finish(png_ptr, length); | |
2516 return; | |
2517 } | |
2518 | |
2519 if (--png_ptr->user_chunk_cache_max == 1) | |
2520 { | |
2521 png_crc_finish(png_ptr, length); | |
2522 png_chunk_benign_error(png_ptr, "no space in chunk cache"); | |
2523 return; | |
2524 } | |
2525 } | |
2526 #endif | |
2527 | |
2528 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) | |
2529 png_chunk_error(png_ptr, "missing IHDR"); | |
2530 | |
2531 if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) | |
2532 png_ptr->mode |= PNG_AFTER_IDAT; | |
2533 | |
2534 buffer = png_read_buffer(png_ptr, length, 2/*silent*/); | |
2535 | |
2536 if (buffer == NULL) | |
2537 { | |
2538 png_crc_finish(png_ptr, length); | |
2539 png_chunk_benign_error(png_ptr, "out of memory"); | |
2540 return; | |
2541 } | |
2542 | |
2543 png_crc_read(png_ptr, buffer, length); | |
2544 | |
2545 if (png_crc_finish(png_ptr, 0) != 0) | |
2546 return; | |
2547 | |
2548 /* TODO: also check that the keyword contents match the spec! */ | |
2549 for (keyword_length = 0; | |
2550 keyword_length < length && buffer[keyword_length] != 0; | |
2551 ++keyword_length) | |
2552 /* Empty loop to find end of name */ ; | |
2553 | |
2554 if (keyword_length > 79 || keyword_length < 1) | |
2555 errmsg = "bad keyword"; | |
2556 | |
2557 /* zTXt must have some LZ data after the keyword, although it may expand to | |
2558 * zero bytes; we need a '\0' at the end of the keyword, the compression type | |
2559 * then the LZ data: | |
2560 */ | |
2561 else if (keyword_length + 3 > length) | |
2562 errmsg = "truncated"; | |
2563 | |
2564 else if (buffer[keyword_length+1] != PNG_COMPRESSION_TYPE_BASE) | |
2565 errmsg = "unknown compression type"; | |
2566 | |
2567 else | |
2568 { | |
2569 png_alloc_size_t uncompressed_length = PNG_SIZE_MAX; | |
2570 | |
2571 /* TODO: at present png_decompress_chunk imposes a single application | |
2572 * level memory limit, this should be split to different values for iCCP | |
2573 * and text chunks. | |
2574 */ | |
2575 if (png_decompress_chunk(png_ptr, length, keyword_length+2, | |
2576 &uncompressed_length, 1/*terminate*/) == Z_STREAM_END) | |
2577 { | |
2578 png_text text; | |
2579 | |
2580 /* It worked; png_ptr->read_buffer now looks like a tEXt chunk except | |
2581 * for the extra compression type byte and the fact that it isn't | |
2582 * necessarily '\0' terminated. | |
2583 */ | |
2584 buffer = png_ptr->read_buffer; | |
2585 buffer[uncompressed_length+(keyword_length+2)] = 0; | |
2586 | |
2587 text.compression = PNG_TEXT_COMPRESSION_zTXt; | |
2588 text.key = (png_charp)buffer; | |
2589 text.text = (png_charp)(buffer + keyword_length+2); | |
2590 text.text_length = uncompressed_length; | |
2591 text.itxt_length = 0; | |
2592 text.lang = NULL; | |
2593 text.lang_key = NULL; | |
2594 | |
2595 if (png_set_text_2(png_ptr, info_ptr, &text, 1) != 0) | |
2596 errmsg = "insufficient memory"; | |
2597 } | |
2598 | |
2599 else | |
2600 errmsg = png_ptr->zstream.msg; | |
2601 } | |
2602 | |
2603 if (errmsg != NULL) | |
2604 png_chunk_benign_error(png_ptr, errmsg); | |
2605 } | |
2606 #endif | |
2607 | |
2608 #ifdef PNG_READ_iTXt_SUPPORTED | |
2609 /* Note: this does not correctly handle chunks that are > 64K under DOS */ | |
2610 void /* PRIVATE */ | |
2611 png_handle_iTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) | |
2612 { | |
2613 png_const_charp errmsg = NULL; | |
2614 png_bytep buffer; | |
2615 png_uint_32 prefix_length; | |
2616 | |
2617 png_debug(1, "in png_handle_iTXt"); | |
2618 | |
2619 #ifdef PNG_USER_LIMITS_SUPPORTED | |
2620 if (png_ptr->user_chunk_cache_max != 0) | |
2621 { | |
2622 if (png_ptr->user_chunk_cache_max == 1) | |
2623 { | |
2624 png_crc_finish(png_ptr, length); | |
2625 return; | |
2626 } | |
2627 | |
2628 if (--png_ptr->user_chunk_cache_max == 1) | |
2629 { | |
2630 png_crc_finish(png_ptr, length); | |
2631 png_chunk_benign_error(png_ptr, "no space in chunk cache"); | |
2632 return; | |
2633 } | |
2634 } | |
2635 #endif | |
2636 | |
2637 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) | |
2638 png_chunk_error(png_ptr, "missing IHDR"); | |
2639 | |
2640 if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) | |
2641 png_ptr->mode |= PNG_AFTER_IDAT; | |
2642 | |
2643 buffer = png_read_buffer(png_ptr, length+1, 1/*warn*/); | |
2644 | |
2645 if (buffer == NULL) | |
2646 { | |
2647 png_crc_finish(png_ptr, length); | |
2648 png_chunk_benign_error(png_ptr, "out of memory"); | |
2649 return; | |
2650 } | |
2651 | |
2652 png_crc_read(png_ptr, buffer, length); | |
2653 | |
2654 if (png_crc_finish(png_ptr, 0) != 0) | |
2655 return; | |
2656 | |
2657 /* First the keyword. */ | |
2658 for (prefix_length=0; | |
2659 prefix_length < length && buffer[prefix_length] != 0; | |
2660 ++prefix_length) | |
2661 /* Empty loop */ ; | |
2662 | |
2663 /* Perform a basic check on the keyword length here. */ | |
2664 if (prefix_length > 79 || prefix_length < 1) | |
2665 errmsg = "bad keyword"; | |
2666 | |
2667 /* Expect keyword, compression flag, compression type, language, translated | |
2668 * keyword (both may be empty but are 0 terminated) then the text, which may | |
2669 * be empty. | |
2670 */ | |
2671 else if (prefix_length + 5 > length) | |
2672 errmsg = "truncated"; | |
2673 | |
2674 else if (buffer[prefix_length+1] == 0 || | |
2675 (buffer[prefix_length+1] == 1 && | |
2676 buffer[prefix_length+2] == PNG_COMPRESSION_TYPE_BASE)) | |
2677 { | |
2678 int compressed = buffer[prefix_length+1] != 0; | |
2679 png_uint_32 language_offset, translated_keyword_offset; | |
2680 png_alloc_size_t uncompressed_length = 0; | |
2681 | |
2682 /* Now the language tag */ | |
2683 prefix_length += 3; | |
2684 language_offset = prefix_length; | |
2685 | |
2686 for (; prefix_length < length && buffer[prefix_length] != 0; | |
2687 ++prefix_length) | |
2688 /* Empty loop */ ; | |
2689 | |
2690 /* WARNING: the length may be invalid here, this is checked below. */ | |
2691 translated_keyword_offset = ++prefix_length; | |
2692 | |
2693 for (; prefix_length < length && buffer[prefix_length] != 0; | |
2694 ++prefix_length) | |
2695 /* Empty loop */ ; | |
2696 | |
2697 /* prefix_length should now be at the trailing '\0' of the translated | |
2698 * keyword, but it may already be over the end. None of this arithmetic | |
2699 * can overflow because chunks are at most 2^31 bytes long, but on 16-bit | |
2700 * systems the available allocation may overflow. | |
2701 */ | |
2702 ++prefix_length; | |
2703 | |
2704 if (compressed == 0 && prefix_length <= length) | |
2705 uncompressed_length = length - prefix_length; | |
2706 | |
2707 else if (compressed != 0 && prefix_length < length) | |
2708 { | |
2709 uncompressed_length = PNG_SIZE_MAX; | |
2710 | |
2711 /* TODO: at present png_decompress_chunk imposes a single application | |
2712 * level memory limit, this should be split to different values for | |
2713 * iCCP and text chunks. | |
2714 */ | |
2715 if (png_decompress_chunk(png_ptr, length, prefix_length, | |
2716 &uncompressed_length, 1/*terminate*/) == Z_STREAM_END) | |
2717 buffer = png_ptr->read_buffer; | |
2718 | |
2719 else | |
2720 errmsg = png_ptr->zstream.msg; | |
2721 } | |
2722 | |
2723 else | |
2724 errmsg = "truncated"; | |
2725 | |
2726 if (errmsg == NULL) | |
2727 { | |
2728 png_text text; | |
2729 | |
2730 buffer[uncompressed_length+prefix_length] = 0; | |
2731 | |
2732 if (compressed == 0) | |
2733 text.compression = PNG_ITXT_COMPRESSION_NONE; | |
2734 | |
2735 else | |
2736 text.compression = PNG_ITXT_COMPRESSION_zTXt; | |
2737 | |
2738 text.key = (png_charp)buffer; | |
2739 text.lang = (png_charp)buffer + language_offset; | |
2740 text.lang_key = (png_charp)buffer + translated_keyword_offset; | |
2741 text.text = (png_charp)buffer + prefix_length; | |
2742 text.text_length = 0; | |
2743 text.itxt_length = uncompressed_length; | |
2744 | |
2745 if (png_set_text_2(png_ptr, info_ptr, &text, 1) != 0) | |
2746 errmsg = "insufficient memory"; | |
2747 } | |
2748 } | |
2749 | |
2750 else | |
2751 errmsg = "bad compression info"; | |
2752 | |
2753 if (errmsg != NULL) | |
2754 png_chunk_benign_error(png_ptr, errmsg); | |
2755 } | |
2756 #endif | |
2757 | |
2758 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED | |
2759 /* Utility function for png_handle_unknown; set up png_ptr::unknown_chunk */ | |
2760 static int | |
2761 png_cache_unknown_chunk(png_structrp png_ptr, png_uint_32 length) | |
2762 { | |
2763 png_alloc_size_t limit = PNG_SIZE_MAX; | |
2764 | |
2765 if (png_ptr->unknown_chunk.data != NULL) | |
2766 { | |
2767 png_free(png_ptr, png_ptr->unknown_chunk.data); | |
2768 png_ptr->unknown_chunk.data = NULL; | |
2769 } | |
2770 | |
2771 # ifdef PNG_SET_USER_LIMITS_SUPPORTED | |
2772 if (png_ptr->user_chunk_malloc_max > 0 && | |
2773 png_ptr->user_chunk_malloc_max < limit) | |
2774 limit = png_ptr->user_chunk_malloc_max; | |
2775 | |
2776 # elif PNG_USER_CHUNK_MALLOC_MAX > 0 | |
2777 if (PNG_USER_CHUNK_MALLOC_MAX < limit) | |
2778 limit = PNG_USER_CHUNK_MALLOC_MAX; | |
2779 # endif | |
2780 | |
2781 if (length <= limit) | |
2782 { | |
2783 PNG_CSTRING_FROM_CHUNK(png_ptr->unknown_chunk.name, png_ptr->chunk_name); | |
2784 /* The following is safe because of the PNG_SIZE_MAX init above */ | |
2785 png_ptr->unknown_chunk.size = (png_size_t)length/*SAFE*/; | |
2786 /* 'mode' is a flag array, only the bottom four bits matter here */ | |
2787 png_ptr->unknown_chunk.location = (png_byte)png_ptr->mode/*SAFE*/; | |
2788 | |
2789 if (length == 0) | |
2790 png_ptr->unknown_chunk.data = NULL; | |
2791 | |
2792 else | |
2793 { | |
2794 /* Do a 'warn' here - it is handled below. */ | |
2795 png_ptr->unknown_chunk.data = png_voidcast(png_bytep, | |
2796 png_malloc_warn(png_ptr, length)); | |
2797 } | |
2798 } | |
2799 | |
2800 if (png_ptr->unknown_chunk.data == NULL && length > 0) | |
2801 { | |
2802 /* This is benign because we clean up correctly */ | |
2803 png_crc_finish(png_ptr, length); | |
2804 png_chunk_benign_error(png_ptr, "unknown chunk exceeds memory limits"); | |
2805 return 0; | |
2806 } | |
2807 | |
2808 else | |
2809 { | |
2810 if (length > 0) | |
2811 png_crc_read(png_ptr, png_ptr->unknown_chunk.data, length); | |
2812 png_crc_finish(png_ptr, 0); | |
2813 return 1; | |
2814 } | |
2815 } | |
2816 #endif /* READ_UNKNOWN_CHUNKS */ | |
2817 | |
2818 /* Handle an unknown, or known but disabled, chunk */ | |
2819 void /* PRIVATE */ | |
2820 png_handle_unknown(png_structrp png_ptr, png_inforp info_ptr, | |
2821 png_uint_32 length, int keep) | |
2822 { | |
2823 int handled = 0; /* the chunk was handled */ | |
2824 | |
2825 png_debug(1, "in png_handle_unknown"); | |
2826 | |
2827 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED | |
2828 /* NOTE: this code is based on the code in libpng-1.4.12 except for fixing | |
2829 * the bug which meant that setting a non-default behavior for a specific | |
2830 * chunk would be ignored (the default was always used unless a user | |
2831 * callback was installed). | |
2832 * | |
2833 * 'keep' is the value from the png_chunk_unknown_handling, the setting for | |
2834 * this specific chunk_name, if PNG_HANDLE_AS_UNKNOWN_SUPPORTED, if not it | |
2835 * will always be PNG_HANDLE_CHUNK_AS_DEFAULT and it needs to be set here. | |
2836 * This is just an optimization to avoid multiple calls to the lookup | |
2837 * function. | |
2838 */ | |
2839 # ifndef PNG_HANDLE_AS_UNKNOWN_SUPPORTED | |
2840 # ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED | |
2841 keep = png_chunk_unknown_handling(png_ptr, png_ptr->chunk_name); | |
2842 # endif | |
2843 # endif | |
2844 | |
2845 /* One of the following methods will read the chunk or skip it (at least one | |
2846 * of these is always defined because this is the only way to switch on | |
2847 * PNG_READ_UNKNOWN_CHUNKS_SUPPORTED) | |
2848 */ | |
2849 # ifdef PNG_READ_USER_CHUNKS_SUPPORTED | |
2850 /* The user callback takes precedence over the chunk keep value, but the | |
2851 * keep value is still required to validate a save of a critical chunk. | |
2852 */ | |
2853 if (png_ptr->read_user_chunk_fn != NULL) | |
2854 { | |
2855 if (png_cache_unknown_chunk(png_ptr, length) != 0) | |
2856 { | |
2857 /* Callback to user unknown chunk handler */ | |
2858 int ret = (*(png_ptr->read_user_chunk_fn))(png_ptr, | |
2859 &png_ptr->unknown_chunk); | |
2860 | |
2861 /* ret is: | |
2862 * negative: An error occurred; png_chunk_error will be called. | |
2863 * zero: The chunk was not handled, the chunk will be discarded | |
2864 * unless png_set_keep_unknown_chunks has been used to set | |
2865 * a 'keep' behavior for this particular chunk, in which | |
2866 * case that will be used. A critical chunk will cause an | |
2867 * error at this point unless it is to be saved. | |
2868 * positive: The chunk was handled, libpng will ignore/discard it. | |
2869 */ | |
2870 if (ret < 0) | |
2871 png_chunk_error(png_ptr, "error in user chunk"); | |
2872 | |
2873 else if (ret == 0) | |
2874 { | |
2875 /* If the keep value is 'default' or 'never' override it, but | |
2876 * still error out on critical chunks unless the keep value is | |
2877 * 'always' While this is weird it is the behavior in 1.4.12. | |
2878 * A possible improvement would be to obey the value set for the | |
2879 * chunk, but this would be an API change that would probably | |
2880 * damage some applications. | |
2881 * | |
2882 * The png_app_warning below catches the case that matters, where | |
2883 * the application has not set specific save or ignore for this | |
2884 * chunk or global save or ignore. | |
2885 */ | |
2886 if (keep < PNG_HANDLE_CHUNK_IF_SAFE) | |
2887 { | |
2888 # ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED | |
2889 if (png_ptr->unknown_default < PNG_HANDLE_CHUNK_IF_SAFE) | |
2890 { | |
2891 png_chunk_warning(png_ptr, "Saving unknown chunk:"); | |
2892 png_app_warning(png_ptr, | |
2893 "forcing save of an unhandled chunk;" | |
2894 " please call png_set_keep_unknown_chunks"); | |
2895 /* with keep = PNG_HANDLE_CHUNK_IF_SAFE */ | |
2896 } | |
2897 # endif | |
2898 keep = PNG_HANDLE_CHUNK_IF_SAFE; | |
2899 } | |
2900 } | |
2901 | |
2902 else /* chunk was handled */ | |
2903 { | |
2904 handled = 1; | |
2905 /* Critical chunks can be safely discarded at this point. */ | |
2906 keep = PNG_HANDLE_CHUNK_NEVER; | |
2907 } | |
2908 } | |
2909 | |
2910 else | |
2911 keep = PNG_HANDLE_CHUNK_NEVER; /* insufficient memory */ | |
2912 } | |
2913 | |
2914 else | |
2915 /* Use the SAVE_UNKNOWN_CHUNKS code or skip the chunk */ | |
2916 # endif /* READ_USER_CHUNKS */ | |
2917 | |
2918 # ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED | |
2919 { | |
2920 /* keep is currently just the per-chunk setting, if there was no | |
2921 * setting change it to the global default now (not that this may | |
2922 * still be AS_DEFAULT) then obtain the cache of the chunk if required, | |
2923 * if not simply skip the chunk. | |
2924 */ | |
2925 if (keep == PNG_HANDLE_CHUNK_AS_DEFAULT) | |
2926 keep = png_ptr->unknown_default; | |
2927 | |
2928 if (keep == PNG_HANDLE_CHUNK_ALWAYS || | |
2929 (keep == PNG_HANDLE_CHUNK_IF_SAFE && | |
2930 PNG_CHUNK_ANCILLARY(png_ptr->chunk_name))) | |
2931 { | |
2932 if (png_cache_unknown_chunk(png_ptr, length) == 0) | |
2933 keep = PNG_HANDLE_CHUNK_NEVER; | |
2934 } | |
2935 | |
2936 else | |
2937 png_crc_finish(png_ptr, length); | |
2938 } | |
2939 # else | |
2940 # ifndef PNG_READ_USER_CHUNKS_SUPPORTED | |
2941 # error no method to support READ_UNKNOWN_CHUNKS | |
2942 # endif | |
2943 | |
2944 { | |
2945 /* If here there is no read callback pointer set and no support is | |
2946 * compiled in to just save the unknown chunks, so simply skip this | |
2947 * chunk. If 'keep' is something other than AS_DEFAULT or NEVER then | |
2948 * the app has erroneously asked for unknown chunk saving when there | |
2949 * is no support. | |
2950 */ | |
2951 if (keep > PNG_HANDLE_CHUNK_NEVER) | |
2952 png_app_error(png_ptr, "no unknown chunk support available"); | |
2953 | |
2954 png_crc_finish(png_ptr, length); | |
2955 } | |
2956 # endif | |
2957 | |
2958 # ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED | |
2959 /* Now store the chunk in the chunk list if appropriate, and if the limits | |
2960 * permit it. | |
2961 */ | |
2962 if (keep == PNG_HANDLE_CHUNK_ALWAYS || | |
2963 (keep == PNG_HANDLE_CHUNK_IF_SAFE && | |
2964 PNG_CHUNK_ANCILLARY(png_ptr->chunk_name))) | |
2965 { | |
2966 # ifdef PNG_USER_LIMITS_SUPPORTED | |
2967 switch (png_ptr->user_chunk_cache_max) | |
2968 { | |
2969 case 2: | |
2970 png_ptr->user_chunk_cache_max = 1; | |
2971 png_chunk_benign_error(png_ptr, "no space in chunk cache"); | |
2972 /* FALL THROUGH */ | |
2973 case 1: | |
2974 /* NOTE: prior to 1.6.0 this case resulted in an unknown critical | |
2975 * chunk being skipped, now there will be a hard error below. | |
2976 */ | |
2977 break; | |
2978 | |
2979 default: /* not at limit */ | |
2980 --(png_ptr->user_chunk_cache_max); | |
2981 /* FALL THROUGH */ | |
2982 case 0: /* no limit */ | |
2983 # endif /* USER_LIMITS */ | |
2984 /* Here when the limit isn't reached or when limits are compiled | |
2985 * out; store the chunk. | |
2986 */ | |
2987 png_set_unknown_chunks(png_ptr, info_ptr, | |
2988 &png_ptr->unknown_chunk, 1); | |
2989 handled = 1; | |
2990 # ifdef PNG_USER_LIMITS_SUPPORTED | |
2991 break; | |
2992 } | |
2993 # endif | |
2994 } | |
2995 # else /* no store support: the chunk must be handled by the user callback */ | |
2996 PNG_UNUSED(info_ptr) | |
2997 # endif | |
2998 | |
2999 /* Regardless of the error handling below the cached data (if any) can be | |
3000 * freed now. Notice that the data is not freed if there is a png_error, but | |
3001 * it will be freed by destroy_read_struct. | |
3002 */ | |
3003 if (png_ptr->unknown_chunk.data != NULL) | |
3004 png_free(png_ptr, png_ptr->unknown_chunk.data); | |
3005 png_ptr->unknown_chunk.data = NULL; | |
3006 | |
3007 #else /* !PNG_READ_UNKNOWN_CHUNKS_SUPPORTED */ | |
3008 /* There is no support to read an unknown chunk, so just skip it. */ | |
3009 png_crc_finish(png_ptr, length); | |
3010 PNG_UNUSED(info_ptr) | |
3011 PNG_UNUSED(keep) | |
3012 #endif /* !READ_UNKNOWN_CHUNKS */ | |
3013 | |
3014 /* Check for unhandled critical chunks */ | |
3015 if (handled == 0 && PNG_CHUNK_CRITICAL(png_ptr->chunk_name)) | |
3016 png_chunk_error(png_ptr, "unhandled critical chunk"); | |
3017 } | |
3018 | |
3019 /* This function is called to verify that a chunk name is valid. | |
3020 * This function can't have the "critical chunk check" incorporated | |
3021 * into it, since in the future we will need to be able to call user | |
3022 * functions to handle unknown critical chunks after we check that | |
3023 * the chunk name itself is valid. | |
3024 */ | |
3025 | |
3026 /* Bit hacking: the test for an invalid byte in the 4 byte chunk name is: | |
3027 * | |
3028 * ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97)) | |
3029 */ | |
3030 | |
3031 void /* PRIVATE */ | |
3032 png_check_chunk_name(png_structrp png_ptr, png_uint_32 chunk_name) | |
3033 { | |
3034 int i; | |
3035 | |
3036 png_debug(1, "in png_check_chunk_name"); | |
3037 | |
3038 for (i=1; i<=4; ++i) | |
3039 { | |
3040 int c = chunk_name & 0xff; | |
3041 | |
3042 if (c < 65 || c > 122 || (c > 90 && c < 97)) | |
3043 png_chunk_error(png_ptr, "invalid chunk type"); | |
3044 | |
3045 chunk_name >>= 8; | |
3046 } | |
3047 } | |
3048 | |
3049 /* Combines the row recently read in with the existing pixels in the row. This | |
3050 * routine takes care of alpha and transparency if requested. This routine also | |
3051 * handles the two methods of progressive display of interlaced images, | |
3052 * depending on the 'display' value; if 'display' is true then the whole row | |
3053 * (dp) is filled from the start by replicating the available pixels. If | |
3054 * 'display' is false only those pixels present in the pass are filled in. | |
3055 */ | |
3056 void /* PRIVATE */ | |
3057 png_combine_row(png_const_structrp png_ptr, png_bytep dp, int display) | |
3058 { | |
3059 unsigned int pixel_depth = png_ptr->transformed_pixel_depth; | |
3060 png_const_bytep sp = png_ptr->row_buf + 1; | |
3061 png_alloc_size_t row_width = png_ptr->width; | |
3062 unsigned int pass = png_ptr->pass; | |
3063 png_bytep end_ptr = 0; | |
3064 png_byte end_byte = 0; | |
3065 unsigned int end_mask; | |
3066 | |
3067 png_debug(1, "in png_combine_row"); | |
3068 | |
3069 /* Added in 1.5.6: it should not be possible to enter this routine until at | |
3070 * least one row has been read from the PNG data and transformed. | |
3071 */ | |
3072 if (pixel_depth == 0) | |
3073 png_error(png_ptr, "internal row logic error"); | |
3074 | |
3075 /* Added in 1.5.4: the pixel depth should match the information returned by | |
3076 * any call to png_read_update_info at this point. Do not continue if we got | |
3077 * this wrong. | |
3078 */ | |
3079 if (png_ptr->info_rowbytes != 0 && png_ptr->info_rowbytes != | |
3080 PNG_ROWBYTES(pixel_depth, row_width)) | |
3081 png_error(png_ptr, "internal row size calculation error"); | |
3082 | |
3083 /* Don't expect this to ever happen: */ | |
3084 if (row_width == 0) | |
3085 png_error(png_ptr, "internal row width error"); | |
3086 | |
3087 /* Preserve the last byte in cases where only part of it will be overwritten, | |
3088 * the multiply below may overflow, we don't care because ANSI-C guarantees | |
3089 * we get the low bits. | |
3090 */ | |
3091 end_mask = (pixel_depth * row_width) & 7; | |
3092 if (end_mask != 0) | |
3093 { | |
3094 /* end_ptr == NULL is a flag to say do nothing */ | |
3095 end_ptr = dp + PNG_ROWBYTES(pixel_depth, row_width) - 1; | |
3096 end_byte = *end_ptr; | |
3097 # ifdef PNG_READ_PACKSWAP_SUPPORTED | |
3098 if ((png_ptr->transformations & PNG_PACKSWAP) != 0) | |
3099 /* little-endian byte */ | |
3100 end_mask = 0xff << end_mask; | |
3101 | |
3102 else /* big-endian byte */ | |
3103 # endif | |
3104 end_mask = 0xff >> end_mask; | |
3105 /* end_mask is now the bits to *keep* from the destination row */ | |
3106 } | |
3107 | |
3108 /* For non-interlaced images this reduces to a memcpy(). A memcpy() | |
3109 * will also happen if interlacing isn't supported or if the application | |
3110 * does not call png_set_interlace_handling(). In the latter cases the | |
3111 * caller just gets a sequence of the unexpanded rows from each interlace | |
3112 * pass. | |
3113 */ | |
3114 #ifdef PNG_READ_INTERLACING_SUPPORTED | |
3115 if (png_ptr->interlaced != 0 && | |
3116 (png_ptr->transformations & PNG_INTERLACE) != 0 && | |
3117 pass < 6 && (display == 0 || | |
3118 /* The following copies everything for 'display' on passes 0, 2 and 4. */ | |
3119 (display == 1 && (pass & 1) != 0))) | |
3120 { | |
3121 /* Narrow images may have no bits in a pass; the caller should handle | |
3122 * this, but this test is cheap: | |
3123 */ | |
3124 if (row_width <= PNG_PASS_START_COL(pass)) | |
3125 return; | |
3126 | |
3127 if (pixel_depth < 8) | |
3128 { | |
3129 /* For pixel depths up to 4 bpp the 8-pixel mask can be expanded to fit | |
3130 * into 32 bits, then a single loop over the bytes using the four byte | |
3131 * values in the 32-bit mask can be used. For the 'display' option the | |
3132 * expanded mask may also not require any masking within a byte. To | |
3133 * make this work the PACKSWAP option must be taken into account - it | |
3134 * simply requires the pixels to be reversed in each byte. | |
3135 * | |
3136 * The 'regular' case requires a mask for each of the first 6 passes, | |
3137 * the 'display' case does a copy for the even passes in the range | |
3138 * 0..6. This has already been handled in the test above. | |
3139 * | |
3140 * The masks are arranged as four bytes with the first byte to use in | |
3141 * the lowest bits (little-endian) regardless of the order (PACKSWAP or | |
3142 * not) of the pixels in each byte. | |
3143 * | |
3144 * NOTE: the whole of this logic depends on the caller of this function | |
3145 * only calling it on rows appropriate to the pass. This function only | |
3146 * understands the 'x' logic; the 'y' logic is handled by the caller. | |
3147 * | |
3148 * The following defines allow generation of compile time constant bit | |
3149 * masks for each pixel depth and each possibility of swapped or not | |
3150 * swapped bytes. Pass 'p' is in the range 0..6; 'x', a pixel index, | |
3151 * is in the range 0..7; and the result is 1 if the pixel is to be | |
3152 * copied in the pass, 0 if not. 'S' is for the sparkle method, 'B' | |
3153 * for the block method. | |
3154 * | |
3155 * With some compilers a compile time expression of the general form: | |
3156 * | |
3157 * (shift >= 32) ? (a >> (shift-32)) : (b >> shift) | |
3158 * | |
3159 * Produces warnings with values of 'shift' in the range 33 to 63 | |
3160 * because the right hand side of the ?: expression is evaluated by | |
3161 * the compiler even though it isn't used. Microsoft Visual C (various | |
3162 * versions) and the Intel C compiler are known to do this. To avoid | |
3163 * this the following macros are used in 1.5.6. This is a temporary | |
3164 * solution to avoid destabilizing the code during the release process. | |
3165 */ | |
3166 # if PNG_USE_COMPILE_TIME_MASKS | |
3167 # define PNG_LSR(x,s) ((x)>>((s) & 0x1f)) | |
3168 # define PNG_LSL(x,s) ((x)<<((s) & 0x1f)) | |
3169 # else | |
3170 # define PNG_LSR(x,s) ((x)>>(s)) | |
3171 # define PNG_LSL(x,s) ((x)<<(s)) | |
3172 # endif | |
3173 # define S_COPY(p,x) (((p)<4 ? PNG_LSR(0x80088822,(3-(p))*8+(7-(x))) :\ | |
3174 PNG_LSR(0xaa55ff00,(7-(p))*8+(7-(x)))) & 1) | |
3175 # define B_COPY(p,x) (((p)<4 ? PNG_LSR(0xff0fff33,(3-(p))*8+(7-(x))) :\ | |
3176 PNG_LSR(0xff55ff00,(7-(p))*8+(7-(x)))) & 1) | |
3177 | |
3178 /* Return a mask for pass 'p' pixel 'x' at depth 'd'. The mask is | |
3179 * little endian - the first pixel is at bit 0 - however the extra | |
3180 * parameter 's' can be set to cause the mask position to be swapped | |
3181 * within each byte, to match the PNG format. This is done by XOR of | |
3182 * the shift with 7, 6 or 4 for bit depths 1, 2 and 4. | |
3183 */ | |
3184 # define PIXEL_MASK(p,x,d,s) \ | |
3185 (PNG_LSL(((PNG_LSL(1U,(d)))-1),(((x)*(d))^((s)?8-(d):0)))) | |
3186 | |
3187 /* Hence generate the appropriate 'block' or 'sparkle' pixel copy mask. | |
3188 */ | |
3189 # define S_MASKx(p,x,d,s) (S_COPY(p,x)?PIXEL_MASK(p,x,d,s):0) | |
3190 # define B_MASKx(p,x,d,s) (B_COPY(p,x)?PIXEL_MASK(p,x,d,s):0) | |
3191 | |
3192 /* Combine 8 of these to get the full mask. For the 1-bpp and 2-bpp | |
3193 * cases the result needs replicating, for the 4-bpp case the above | |
3194 * generates a full 32 bits. | |
3195 */ | |
3196 # define MASK_EXPAND(m,d) ((m)*((d)==1?0x01010101:((d)==2?0x00010001:1))) | |
3197 | |
3198 # define S_MASK(p,d,s) MASK_EXPAND(S_MASKx(p,0,d,s) + S_MASKx(p,1,d,s) +\ | |
3199 S_MASKx(p,2,d,s) + S_MASKx(p,3,d,s) + S_MASKx(p,4,d,s) +\ | |
3200 S_MASKx(p,5,d,s) + S_MASKx(p,6,d,s) + S_MASKx(p,7,d,s), d) | |
3201 | |
3202 # define B_MASK(p,d,s) MASK_EXPAND(B_MASKx(p,0,d,s) + B_MASKx(p,1,d,s) +\ | |
3203 B_MASKx(p,2,d,s) + B_MASKx(p,3,d,s) + B_MASKx(p,4,d,s) +\ | |
3204 B_MASKx(p,5,d,s) + B_MASKx(p,6,d,s) + B_MASKx(p,7,d,s), d) | |
3205 | |
3206 #if PNG_USE_COMPILE_TIME_MASKS | |
3207 /* Utility macros to construct all the masks for a depth/swap | |
3208 * combination. The 's' parameter says whether the format is PNG | |
3209 * (big endian bytes) or not. Only the three odd-numbered passes are | |
3210 * required for the display/block algorithm. | |
3211 */ | |
3212 # define S_MASKS(d,s) { S_MASK(0,d,s), S_MASK(1,d,s), S_MASK(2,d,s),\ | |
3213 S_MASK(3,d,s), S_MASK(4,d,s), S_MASK(5,d,s) } | |
3214 | |
3215 # define B_MASKS(d,s) { B_MASK(1,d,s), B_MASK(3,d,s), B_MASK(5,d,s) } | |
3216 | |
3217 # define DEPTH_INDEX(d) ((d)==1?0:((d)==2?1:2)) | |
3218 | |
3219 /* Hence the pre-compiled masks indexed by PACKSWAP (or not), depth and | |
3220 * then pass: | |
3221 */ | |
3222 static PNG_CONST png_uint_32 row_mask[2/*PACKSWAP*/][3/*depth*/][6] = | |
3223 { | |
3224 /* Little-endian byte masks for PACKSWAP */ | |
3225 { S_MASKS(1,0), S_MASKS(2,0), S_MASKS(4,0) }, | |
3226 /* Normal (big-endian byte) masks - PNG format */ | |
3227 { S_MASKS(1,1), S_MASKS(2,1), S_MASKS(4,1) } | |
3228 }; | |
3229 | |
3230 /* display_mask has only three entries for the odd passes, so index by | |
3231 * pass>>1. | |
3232 */ | |
3233 static PNG_CONST png_uint_32 display_mask[2][3][3] = | |
3234 { | |
3235 /* Little-endian byte masks for PACKSWAP */ | |
3236 { B_MASKS(1,0), B_MASKS(2,0), B_MASKS(4,0) }, | |
3237 /* Normal (big-endian byte) masks - PNG format */ | |
3238 { B_MASKS(1,1), B_MASKS(2,1), B_MASKS(4,1) } | |
3239 }; | |
3240 | |
3241 # define MASK(pass,depth,display,png)\ | |
3242 ((display)?display_mask[png][DEPTH_INDEX(depth)][pass>>1]:\ | |
3243 row_mask[png][DEPTH_INDEX(depth)][pass]) | |
3244 | |
3245 #else /* !PNG_USE_COMPILE_TIME_MASKS */ | |
3246 /* This is the runtime alternative: it seems unlikely that this will | |
3247 * ever be either smaller or faster than the compile time approach. | |
3248 */ | |
3249 # define MASK(pass,depth,display,png)\ | |
3250 ((display)?B_MASK(pass,depth,png):S_MASK(pass,depth,png)) | |
3251 #endif /* !USE_COMPILE_TIME_MASKS */ | |
3252 | |
3253 /* Use the appropriate mask to copy the required bits. In some cases | |
3254 * the byte mask will be 0 or 0xff; optimize these cases. row_width is | |
3255 * the number of pixels, but the code copies bytes, so it is necessary | |
3256 * to special case the end. | |
3257 */ | |
3258 png_uint_32 pixels_per_byte = 8 / pixel_depth; | |
3259 png_uint_32 mask; | |
3260 | |
3261 # ifdef PNG_READ_PACKSWAP_SUPPORTED | |
3262 if ((png_ptr->transformations & PNG_PACKSWAP) != 0) | |
3263 mask = MASK(pass, pixel_depth, display, 0); | |
3264 | |
3265 else | |
3266 # endif | |
3267 mask = MASK(pass, pixel_depth, display, 1); | |
3268 | |
3269 for (;;) | |
3270 { | |
3271 png_uint_32 m; | |
3272 | |
3273 /* It doesn't matter in the following if png_uint_32 has more than | |
3274 * 32 bits because the high bits always match those in m<<24; it is, | |
3275 * however, essential to use OR here, not +, because of this. | |
3276 */ | |
3277 m = mask; | |
3278 mask = (m >> 8) | (m << 24); /* rotate right to good compilers */ | |
3279 m &= 0xff; | |
3280 | |
3281 if (m != 0) /* something to copy */ | |
3282 { | |
3283 if (m != 0xff) | |
3284 *dp = (png_byte)((*dp & ~m) | (*sp & m)); | |
3285 else | |
3286 *dp = *sp; | |
3287 } | |
3288 | |
3289 /* NOTE: this may overwrite the last byte with garbage if the image | |
3290 * is not an exact number of bytes wide; libpng has always done | |
3291 * this. | |
3292 */ | |
3293 if (row_width <= pixels_per_byte) | |
3294 break; /* May need to restore part of the last byte */ | |
3295 | |
3296 row_width -= pixels_per_byte; | |
3297 ++dp; | |
3298 ++sp; | |
3299 } | |
3300 } | |
3301 | |
3302 else /* pixel_depth >= 8 */ | |
3303 { | |
3304 unsigned int bytes_to_copy, bytes_to_jump; | |
3305 | |
3306 /* Validate the depth - it must be a multiple of 8 */ | |
3307 if (pixel_depth & 7) | |
3308 png_error(png_ptr, "invalid user transform pixel depth"); | |
3309 | |
3310 pixel_depth >>= 3; /* now in bytes */ | |
3311 row_width *= pixel_depth; | |
3312 | |
3313 /* Regardless of pass number the Adam 7 interlace always results in a | |
3314 * fixed number of pixels to copy then to skip. There may be a | |
3315 * different number of pixels to skip at the start though. | |
3316 */ | |
3317 { | |
3318 unsigned int offset = PNG_PASS_START_COL(pass) * pixel_depth; | |
3319 | |
3320 row_width -= offset; | |
3321 dp += offset; | |
3322 sp += offset; | |
3323 } | |
3324 | |
3325 /* Work out the bytes to copy. */ | |
3326 if (display != 0) | |
3327 { | |
3328 /* When doing the 'block' algorithm the pixel in the pass gets | |
3329 * replicated to adjacent pixels. This is why the even (0,2,4,6) | |
3330 * passes are skipped above - the entire expanded row is copied. | |
3331 */ | |
3332 bytes_to_copy = (1<<((6-pass)>>1)) * pixel_depth; | |
3333 | |
3334 /* But don't allow this number to exceed the actual row width. */ | |
3335 if (bytes_to_copy > row_width) | |
3336 bytes_to_copy = (unsigned int)/*SAFE*/row_width; | |
3337 } | |
3338 | |
3339 else /* normal row; Adam7 only ever gives us one pixel to copy. */ | |
3340 bytes_to_copy = pixel_depth; | |
3341 | |
3342 /* In Adam7 there is a constant offset between where the pixels go. */ | |
3343 bytes_to_jump = PNG_PASS_COL_OFFSET(pass) * pixel_depth; | |
3344 | |
3345 /* And simply copy these bytes. Some optimization is possible here, | |
3346 * depending on the value of 'bytes_to_copy'. Special case the low | |
3347 * byte counts, which we know to be frequent. | |
3348 * | |
3349 * Notice that these cases all 'return' rather than 'break' - this | |
3350 * avoids an unnecessary test on whether to restore the last byte | |
3351 * below. | |
3352 */ | |
3353 switch (bytes_to_copy) | |
3354 { | |
3355 case 1: | |
3356 for (;;) | |
3357 { | |
3358 *dp = *sp; | |
3359 | |
3360 if (row_width <= bytes_to_jump) | |
3361 return; | |
3362 | |
3363 dp += bytes_to_jump; | |
3364 sp += bytes_to_jump; | |
3365 row_width -= bytes_to_jump; | |
3366 } | |
3367 | |
3368 case 2: | |
3369 /* There is a possibility of a partial copy at the end here; this | |
3370 * slows the code down somewhat. | |
3371 */ | |
3372 do | |
3373 { | |
3374 dp[0] = sp[0], dp[1] = sp[1]; | |
3375 | |
3376 if (row_width <= bytes_to_jump) | |
3377 return; | |
3378 | |
3379 sp += bytes_to_jump; | |
3380 dp += bytes_to_jump; | |
3381 row_width -= bytes_to_jump; | |
3382 } | |
3383 while (row_width > 1); | |
3384 | |
3385 /* And there can only be one byte left at this point: */ | |
3386 *dp = *sp; | |
3387 return; | |
3388 | |
3389 case 3: | |
3390 /* This can only be the RGB case, so each copy is exactly one | |
3391 * pixel and it is not necessary to check for a partial copy. | |
3392 */ | |
3393 for (;;) | |
3394 { | |
3395 dp[0] = sp[0], dp[1] = sp[1], dp[2] = sp[2]; | |
3396 | |
3397 if (row_width <= bytes_to_jump) | |
3398 return; | |
3399 | |
3400 sp += bytes_to_jump; | |
3401 dp += bytes_to_jump; | |
3402 row_width -= bytes_to_jump; | |
3403 } | |
3404 | |
3405 default: | |
3406 #if PNG_ALIGN_TYPE != PNG_ALIGN_NONE | |
3407 /* Check for double byte alignment and, if possible, use a | |
3408 * 16-bit copy. Don't attempt this for narrow images - ones that | |
3409 * are less than an interlace panel wide. Don't attempt it for | |
3410 * wide bytes_to_copy either - use the memcpy there. | |
3411 */ | |
3412 if (bytes_to_copy < 16 /*else use memcpy*/ && | |
3413 png_isaligned(dp, png_uint_16) && | |
3414 png_isaligned(sp, png_uint_16) && | |
3415 bytes_to_copy % (sizeof (png_uint_16)) == 0 && | |
3416 bytes_to_jump % (sizeof (png_uint_16)) == 0) | |
3417 { | |
3418 /* Everything is aligned for png_uint_16 copies, but try for | |
3419 * png_uint_32 first. | |
3420 */ | |
3421 if (png_isaligned(dp, png_uint_32) != 0 && | |
3422 png_isaligned(sp, png_uint_32) != 0 && | |
3423 bytes_to_copy % (sizeof (png_uint_32)) == 0 && | |
3424 bytes_to_jump % (sizeof (png_uint_32)) == 0) | |
3425 { | |
3426 png_uint_32p dp32 = png_aligncast(png_uint_32p,dp); | |
3427 png_const_uint_32p sp32 = png_aligncastconst( | |
3428 png_const_uint_32p, sp); | |
3429 size_t skip = (bytes_to_jump-bytes_to_copy) / | |
3430 (sizeof (png_uint_32)); | |
3431 | |
3432 do | |
3433 { | |
3434 size_t c = bytes_to_copy; | |
3435 do | |
3436 { | |
3437 *dp32++ = *sp32++; | |
3438 c -= (sizeof (png_uint_32)); | |
3439 } | |
3440 while (c > 0); | |
3441 | |
3442 if (row_width <= bytes_to_jump) | |
3443 return; | |
3444 | |
3445 dp32 += skip; | |
3446 sp32 += skip; | |
3447 row_width -= bytes_to_jump; | |
3448 } | |
3449 while (bytes_to_copy <= row_width); | |
3450 | |
3451 /* Get to here when the row_width truncates the final copy. | |
3452 * There will be 1-3 bytes left to copy, so don't try the | |
3453 * 16-bit loop below. | |
3454 */ | |
3455 dp = (png_bytep)dp32; | |
3456 sp = (png_const_bytep)sp32; | |
3457 do | |
3458 *dp++ = *sp++; | |
3459 while (--row_width > 0); | |
3460 return; | |
3461 } | |
3462 | |
3463 /* Else do it in 16-bit quantities, but only if the size is | |
3464 * not too large. | |
3465 */ | |
3466 else | |
3467 { | |
3468 png_uint_16p dp16 = png_aligncast(png_uint_16p, dp); | |
3469 png_const_uint_16p sp16 = png_aligncastconst( | |
3470 png_const_uint_16p, sp); | |
3471 size_t skip = (bytes_to_jump-bytes_to_copy) / | |
3472 (sizeof (png_uint_16)); | |
3473 | |
3474 do | |
3475 { | |
3476 size_t c = bytes_to_copy; | |
3477 do | |
3478 { | |
3479 *dp16++ = *sp16++; | |
3480 c -= (sizeof (png_uint_16)); | |
3481 } | |
3482 while (c > 0); | |
3483 | |
3484 if (row_width <= bytes_to_jump) | |
3485 return; | |
3486 | |
3487 dp16 += skip; | |
3488 sp16 += skip; | |
3489 row_width -= bytes_to_jump; | |
3490 } | |
3491 while (bytes_to_copy <= row_width); | |
3492 | |
3493 /* End of row - 1 byte left, bytes_to_copy > row_width: */ | |
3494 dp = (png_bytep)dp16; | |
3495 sp = (png_const_bytep)sp16; | |
3496 do | |
3497 *dp++ = *sp++; | |
3498 while (--row_width > 0); | |
3499 return; | |
3500 } | |
3501 } | |
3502 #endif /* ALIGN_TYPE code */ | |
3503 | |
3504 /* The true default - use a memcpy: */ | |
3505 for (;;) | |
3506 { | |
3507 memcpy(dp, sp, bytes_to_copy); | |
3508 | |
3509 if (row_width <= bytes_to_jump) | |
3510 return; | |
3511 | |
3512 sp += bytes_to_jump; | |
3513 dp += bytes_to_jump; | |
3514 row_width -= bytes_to_jump; | |
3515 if (bytes_to_copy > row_width) | |
3516 bytes_to_copy = (unsigned int)/*SAFE*/row_width; | |
3517 } | |
3518 } | |
3519 | |
3520 /* NOT REACHED*/ | |
3521 } /* pixel_depth >= 8 */ | |
3522 | |
3523 /* Here if pixel_depth < 8 to check 'end_ptr' below. */ | |
3524 } | |
3525 else | |
3526 #endif /* READ_INTERLACING */ | |
3527 | |
3528 /* If here then the switch above wasn't used so just memcpy the whole row | |
3529 * from the temporary row buffer (notice that this overwrites the end of the | |
3530 * destination row if it is a partial byte.) | |
3531 */ | |
3532 memcpy(dp, sp, PNG_ROWBYTES(pixel_depth, row_width)); | |
3533 | |
3534 /* Restore the overwritten bits from the last byte if necessary. */ | |
3535 if (end_ptr != NULL) | |
3536 *end_ptr = (png_byte)((end_byte & end_mask) | (*end_ptr & ~end_mask)); | |
3537 } | |
3538 | |
3539 #ifdef PNG_READ_INTERLACING_SUPPORTED | |
3540 void /* PRIVATE */ | |
3541 png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass, | |
3542 png_uint_32 transformations /* Because these may affect the byte layout */) | |
3543 { | |
3544 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ | |
3545 /* Offset to next interlace block */ | |
3546 static PNG_CONST int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1}; | |
3547 | |
3548 png_debug(1, "in png_do_read_interlace"); | |
3549 if (row != NULL && row_info != NULL) | |
3550 { | |
3551 png_uint_32 final_width; | |
3552 | |
3553 final_width = row_info->width * png_pass_inc[pass]; | |
3554 | |
3555 switch (row_info->pixel_depth) | |
3556 { | |
3557 case 1: | |
3558 { | |
3559 png_bytep sp = row + (png_size_t)((row_info->width - 1) >> 3); | |
3560 png_bytep dp = row + (png_size_t)((final_width - 1) >> 3); | |
3561 int sshift, dshift; | |
3562 int s_start, s_end, s_inc; | |
3563 int jstop = png_pass_inc[pass]; | |
3564 png_byte v; | |
3565 png_uint_32 i; | |
3566 int j; | |
3567 | |
3568 #ifdef PNG_READ_PACKSWAP_SUPPORTED | |
3569 if ((transformations & PNG_PACKSWAP) != 0) | |
3570 { | |
3571 sshift = (int)((row_info->width + 7) & 0x07); | |
3572 dshift = (int)((final_width + 7) & 0x07); | |
3573 s_start = 7; | |
3574 s_end = 0; | |
3575 s_inc = -1; | |
3576 } | |
3577 | |
3578 else | |
3579 #endif | |
3580 { | |
3581 sshift = 7 - (int)((row_info->width + 7) & 0x07); | |
3582 dshift = 7 - (int)((final_width + 7) & 0x07); | |
3583 s_start = 0; | |
3584 s_end = 7; | |
3585 s_inc = 1; | |
3586 } | |
3587 | |
3588 for (i = 0; i < row_info->width; i++) | |
3589 { | |
3590 v = (png_byte)((*sp >> sshift) & 0x01); | |
3591 for (j = 0; j < jstop; j++) | |
3592 { | |
3593 unsigned int tmp = *dp & (0x7f7f >> (7 - dshift)); | |
3594 tmp |= v << dshift; | |
3595 *dp = (png_byte)(tmp & 0xff); | |
3596 | |
3597 if (dshift == s_end) | |
3598 { | |
3599 dshift = s_start; | |
3600 dp--; | |
3601 } | |
3602 | |
3603 else | |
3604 dshift += s_inc; | |
3605 } | |
3606 | |
3607 if (sshift == s_end) | |
3608 { | |
3609 sshift = s_start; | |
3610 sp--; | |
3611 } | |
3612 | |
3613 else | |
3614 sshift += s_inc; | |
3615 } | |
3616 break; | |
3617 } | |
3618 | |
3619 case 2: | |
3620 { | |
3621 png_bytep sp = row + (png_uint_32)((row_info->width - 1) >> 2); | |
3622 png_bytep dp = row + (png_uint_32)((final_width - 1) >> 2); | |
3623 int sshift, dshift; | |
3624 int s_start, s_end, s_inc; | |
3625 int jstop = png_pass_inc[pass]; | |
3626 png_uint_32 i; | |
3627 | |
3628 #ifdef PNG_READ_PACKSWAP_SUPPORTED | |
3629 if ((transformations & PNG_PACKSWAP) != 0) | |
3630 { | |
3631 sshift = (int)(((row_info->width + 3) & 0x03) << 1); | |
3632 dshift = (int)(((final_width + 3) & 0x03) << 1); | |
3633 s_start = 6; | |
3634 s_end = 0; | |
3635 s_inc = -2; | |
3636 } | |
3637 | |
3638 else | |
3639 #endif | |
3640 { | |
3641 sshift = (int)((3 - ((row_info->width + 3) & 0x03)) << 1); | |
3642 dshift = (int)((3 - ((final_width + 3) & 0x03)) << 1); | |
3643 s_start = 0; | |
3644 s_end = 6; | |
3645 s_inc = 2; | |
3646 } | |
3647 | |
3648 for (i = 0; i < row_info->width; i++) | |
3649 { | |
3650 png_byte v; | |
3651 int j; | |
3652 | |
3653 v = (png_byte)((*sp >> sshift) & 0x03); | |
3654 for (j = 0; j < jstop; j++) | |
3655 { | |
3656 unsigned int tmp = *dp & (0x3f3f >> (6 - dshift)); | |
3657 tmp |= v << dshift; | |
3658 *dp = (png_byte)(tmp & 0xff); | |
3659 | |
3660 if (dshift == s_end) | |
3661 { | |
3662 dshift = s_start; | |
3663 dp--; | |
3664 } | |
3665 | |
3666 else | |
3667 dshift += s_inc; | |
3668 } | |
3669 | |
3670 if (sshift == s_end) | |
3671 { | |
3672 sshift = s_start; | |
3673 sp--; | |
3674 } | |
3675 | |
3676 else | |
3677 sshift += s_inc; | |
3678 } | |
3679 break; | |
3680 } | |
3681 | |
3682 case 4: | |
3683 { | |
3684 png_bytep sp = row + (png_size_t)((row_info->width - 1) >> 1); | |
3685 png_bytep dp = row + (png_size_t)((final_width - 1) >> 1); | |
3686 int sshift, dshift; | |
3687 int s_start, s_end, s_inc; | |
3688 png_uint_32 i; | |
3689 int jstop = png_pass_inc[pass]; | |
3690 | |
3691 #ifdef PNG_READ_PACKSWAP_SUPPORTED | |
3692 if ((transformations & PNG_PACKSWAP) != 0) | |
3693 { | |
3694 sshift = (int)(((row_info->width + 1) & 0x01) << 2); | |
3695 dshift = (int)(((final_width + 1) & 0x01) << 2); | |
3696 s_start = 4; | |
3697 s_end = 0; | |
3698 s_inc = -4; | |
3699 } | |
3700 | |
3701 else | |
3702 #endif | |
3703 { | |
3704 sshift = (int)((1 - ((row_info->width + 1) & 0x01)) << 2); | |
3705 dshift = (int)((1 - ((final_width + 1) & 0x01)) << 2); | |
3706 s_start = 0; | |
3707 s_end = 4; | |
3708 s_inc = 4; | |
3709 } | |
3710 | |
3711 for (i = 0; i < row_info->width; i++) | |
3712 { | |
3713 png_byte v = (png_byte)((*sp >> sshift) & 0x0f); | |
3714 int j; | |
3715 | |
3716 for (j = 0; j < jstop; j++) | |
3717 { | |
3718 unsigned int tmp = *dp & (0xf0f >> (4 - dshift)); | |
3719 tmp |= v << dshift; | |
3720 *dp = (png_byte)(tmp & 0xff); | |
3721 | |
3722 if (dshift == s_end) | |
3723 { | |
3724 dshift = s_start; | |
3725 dp--; | |
3726 } | |
3727 | |
3728 else | |
3729 dshift += s_inc; | |
3730 } | |
3731 | |
3732 if (sshift == s_end) | |
3733 { | |
3734 sshift = s_start; | |
3735 sp--; | |
3736 } | |
3737 | |
3738 else | |
3739 sshift += s_inc; | |
3740 } | |
3741 break; | |
3742 } | |
3743 | |
3744 default: | |
3745 { | |
3746 png_size_t pixel_bytes = (row_info->pixel_depth >> 3); | |
3747 | |
3748 png_bytep sp = row + (png_size_t)(row_info->width - 1) | |
3749 * pixel_bytes; | |
3750 | |
3751 png_bytep dp = row + (png_size_t)(final_width - 1) * pixel_bytes; | |
3752 | |
3753 int jstop = png_pass_inc[pass]; | |
3754 png_uint_32 i; | |
3755 | |
3756 for (i = 0; i < row_info->width; i++) | |
3757 { | |
3758 png_byte v[8]; /* SAFE; pixel_depth does not exceed 64 */ | |
3759 int j; | |
3760 | |
3761 memcpy(v, sp, pixel_bytes); | |
3762 | |
3763 for (j = 0; j < jstop; j++) | |
3764 { | |
3765 memcpy(dp, v, pixel_bytes); | |
3766 dp -= pixel_bytes; | |
3767 } | |
3768 | |
3769 sp -= pixel_bytes; | |
3770 } | |
3771 break; | |
3772 } | |
3773 } | |
3774 | |
3775 row_info->width = final_width; | |
3776 row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, final_width); | |
3777 } | |
3778 #ifndef PNG_READ_PACKSWAP_SUPPORTED | |
3779 PNG_UNUSED(transformations) /* Silence compiler warning */ | |
3780 #endif | |
3781 } | |
3782 #endif /* READ_INTERLACING */ | |
3783 | |
3784 static void | |
3785 png_read_filter_row_sub(png_row_infop row_info, png_bytep row, | |
3786 png_const_bytep prev_row) | |
3787 { | |
3788 png_size_t i; | |
3789 png_size_t istop = row_info->rowbytes; | |
3790 unsigned int bpp = (row_info->pixel_depth + 7) >> 3; | |
3791 png_bytep rp = row + bpp; | |
3792 | |
3793 PNG_UNUSED(prev_row) | |
3794 | |
3795 for (i = bpp; i < istop; i++) | |
3796 { | |
3797 *rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 0xff); | |
3798 rp++; | |
3799 } | |
3800 } | |
3801 | |
3802 static void | |
3803 png_read_filter_row_up(png_row_infop row_info, png_bytep row, | |
3804 png_const_bytep prev_row) | |
3805 { | |
3806 png_size_t i; | |
3807 png_size_t istop = row_info->rowbytes; | |
3808 png_bytep rp = row; | |
3809 png_const_bytep pp = prev_row; | |
3810 | |
3811 for (i = 0; i < istop; i++) | |
3812 { | |
3813 *rp = (png_byte)(((int)(*rp) + (int)(*pp++)) & 0xff); | |
3814 rp++; | |
3815 } | |
3816 } | |
3817 | |
3818 static void | |
3819 png_read_filter_row_avg(png_row_infop row_info, png_bytep row, | |
3820 png_const_bytep prev_row) | |
3821 { | |
3822 png_size_t i; | |
3823 png_bytep rp = row; | |
3824 png_const_bytep pp = prev_row; | |
3825 unsigned int bpp = (row_info->pixel_depth + 7) >> 3; | |
3826 png_size_t istop = row_info->rowbytes - bpp; | |
3827 | |
3828 for (i = 0; i < bpp; i++) | |
3829 { | |
3830 *rp = (png_byte)(((int)(*rp) + | |
3831 ((int)(*pp++) / 2 )) & 0xff); | |
3832 | |
3833 rp++; | |
3834 } | |
3835 | |
3836 for (i = 0; i < istop; i++) | |
3837 { | |
3838 *rp = (png_byte)(((int)(*rp) + | |
3839 (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff); | |
3840 | |
3841 rp++; | |
3842 } | |
3843 } | |
3844 | |
3845 static void | |
3846 png_read_filter_row_paeth_1byte_pixel(png_row_infop row_info, png_bytep row, | |
3847 png_const_bytep prev_row) | |
3848 { | |
3849 png_bytep rp_end = row + row_info->rowbytes; | |
3850 int a, c; | |
3851 | |
3852 /* First pixel/byte */ | |
3853 c = *prev_row++; | |
3854 a = *row + c; | |
3855 *row++ = (png_byte)a; | |
3856 | |
3857 /* Remainder */ | |
3858 while (row < rp_end) | |
3859 { | |
3860 int b, pa, pb, pc, p; | |
3861 | |
3862 a &= 0xff; /* From previous iteration or start */ | |
3863 b = *prev_row++; | |
3864 | |
3865 p = b - c; | |
3866 pc = a - c; | |
3867 | |
3868 #ifdef PNG_USE_ABS | |
3869 pa = abs(p); | |
3870 pb = abs(pc); | |
3871 pc = abs(p + pc); | |
3872 #else | |
3873 pa = p < 0 ? -p : p; | |
3874 pb = pc < 0 ? -pc : pc; | |
3875 pc = (p + pc) < 0 ? -(p + pc) : p + pc; | |
3876 #endif | |
3877 | |
3878 /* Find the best predictor, the least of pa, pb, pc favoring the earlier | |
3879 * ones in the case of a tie. | |
3880 */ | |
3881 if (pb < pa) pa = pb, a = b; | |
3882 if (pc < pa) a = c; | |
3883 | |
3884 /* Calculate the current pixel in a, and move the previous row pixel to c | |
3885 * for the next time round the loop | |
3886 */ | |
3887 c = b; | |
3888 a += *row; | |
3889 *row++ = (png_byte)a; | |
3890 } | |
3891 } | |
3892 | |
3893 static void | |
3894 png_read_filter_row_paeth_multibyte_pixel(png_row_infop row_info, png_bytep row, | |
3895 png_const_bytep prev_row) | |
3896 { | |
3897 int bpp = (row_info->pixel_depth + 7) >> 3; | |
3898 png_bytep rp_end = row + bpp; | |
3899 | |
3900 /* Process the first pixel in the row completely (this is the same as 'up' | |
3901 * because there is only one candidate predictor for the first row). | |
3902 */ | |
3903 while (row < rp_end) | |
3904 { | |
3905 int a = *row + *prev_row++; | |
3906 *row++ = (png_byte)a; | |
3907 } | |
3908 | |
3909 /* Remainder */ | |
3910 rp_end += row_info->rowbytes - bpp; | |
3911 | |
3912 while (row < rp_end) | |
3913 { | |
3914 int a, b, c, pa, pb, pc, p; | |
3915 | |
3916 c = *(prev_row - bpp); | |
3917 a = *(row - bpp); | |
3918 b = *prev_row++; | |
3919 | |
3920 p = b - c; | |
3921 pc = a - c; | |
3922 | |
3923 #ifdef PNG_USE_ABS | |
3924 pa = abs(p); | |
3925 pb = abs(pc); | |
3926 pc = abs(p + pc); | |
3927 #else | |
3928 pa = p < 0 ? -p : p; | |
3929 pb = pc < 0 ? -pc : pc; | |
3930 pc = (p + pc) < 0 ? -(p + pc) : p + pc; | |
3931 #endif | |
3932 | |
3933 if (pb < pa) pa = pb, a = b; | |
3934 if (pc < pa) a = c; | |
3935 | |
3936 a += *row; | |
3937 *row++ = (png_byte)a; | |
3938 } | |
3939 } | |
3940 | |
3941 static void | |
3942 png_init_filter_functions(png_structrp pp) | |
3943 /* This function is called once for every PNG image (except for PNG images | |
3944 * that only use PNG_FILTER_VALUE_NONE for all rows) to set the | |
3945 * implementations required to reverse the filtering of PNG rows. Reversing | |
3946 * the filter is the first transformation performed on the row data. It is | |
3947 * performed in place, therefore an implementation can be selected based on | |
3948 * the image pixel format. If the implementation depends on image width then | |
3949 * take care to ensure that it works correctly if the image is interlaced - | |
3950 * interlacing causes the actual row width to vary. | |
3951 */ | |
3952 { | |
3953 unsigned int bpp = (pp->pixel_depth + 7) >> 3; | |
3954 | |
3955 pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub; | |
3956 pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up; | |
3957 pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg; | |
3958 if (bpp == 1) | |
3959 pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = | |
3960 png_read_filter_row_paeth_1byte_pixel; | |
3961 else | |
3962 pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = | |
3963 png_read_filter_row_paeth_multibyte_pixel; | |
3964 | |
3965 #ifdef PNG_FILTER_OPTIMIZATIONS | |
3966 /* To use this define PNG_FILTER_OPTIMIZATIONS as the name of a function to | |
3967 * call to install hardware optimizations for the above functions; simply | |
3968 * replace whatever elements of the pp->read_filter[] array with a hardware | |
3969 * specific (or, for that matter, generic) optimization. | |
3970 * | |
3971 * To see an example of this examine what configure.ac does when | |
3972 * --enable-arm-neon is specified on the command line. | |
3973 */ | |
3974 PNG_FILTER_OPTIMIZATIONS(pp, bpp); | |
3975 #endif | |
3976 } | |
3977 | |
3978 void /* PRIVATE */ | |
3979 png_read_filter_row(png_structrp pp, png_row_infop row_info, png_bytep row, | |
3980 png_const_bytep prev_row, int filter) | |
3981 { | |
3982 /* OPTIMIZATION: DO NOT MODIFY THIS FUNCTION, instead #define | |
3983 * PNG_FILTER_OPTIMIZATIONS to a function that overrides the generic | |
3984 * implementations. See png_init_filter_functions above. | |
3985 */ | |
3986 if (filter > PNG_FILTER_VALUE_NONE && filter < PNG_FILTER_VALUE_LAST) | |
3987 { | |
3988 if (pp->read_filter[0] == NULL) | |
3989 png_init_filter_functions(pp); | |
3990 | |
3991 pp->read_filter[filter-1](row_info, row, prev_row); | |
3992 } | |
3993 } | |
3994 | |
3995 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED | |
3996 void /* PRIVATE */ | |
3997 png_read_IDAT_data(png_structrp png_ptr, png_bytep output, | |
3998 png_alloc_size_t avail_out) | |
3999 { | |
4000 /* Loop reading IDATs and decompressing the result into output[avail_out] */ | |
4001 png_ptr->zstream.next_out = output; | |
4002 png_ptr->zstream.avail_out = 0; /* safety: set below */ | |
4003 | |
4004 if (output == NULL) | |
4005 avail_out = 0; | |
4006 | |
4007 do | |
4008 { | |
4009 int ret; | |
4010 png_byte tmpbuf[PNG_INFLATE_BUF_SIZE]; | |
4011 | |
4012 if (png_ptr->zstream.avail_in == 0) | |
4013 { | |
4014 uInt avail_in; | |
4015 png_bytep buffer; | |
4016 | |
4017 while (png_ptr->idat_size == 0) | |
4018 { | |
4019 png_crc_finish(png_ptr, 0); | |
4020 | |
4021 png_ptr->idat_size = png_read_chunk_header(png_ptr); | |
4022 /* This is an error even in the 'check' case because the code just | |
4023 * consumed a non-IDAT header. | |
4024 */ | |
4025 if (png_ptr->chunk_name != png_IDAT) | |
4026 png_error(png_ptr, "Not enough image data"); | |
4027 } | |
4028 | |
4029 avail_in = png_ptr->IDAT_read_size; | |
4030 | |
4031 if (avail_in > png_ptr->idat_size) | |
4032 avail_in = (uInt)png_ptr->idat_size; | |
4033 | |
4034 /* A PNG with a gradually increasing IDAT size will defeat this attempt | |
4035 * to minimize memory usage by causing lots of re-allocs, but | |
4036 * realistically doing IDAT_read_size re-allocs is not likely to be a | |
4037 * big problem. | |
4038 */ | |
4039 buffer = png_read_buffer(png_ptr, avail_in, 0/*error*/); | |
4040 | |
4041 png_crc_read(png_ptr, buffer, avail_in); | |
4042 png_ptr->idat_size -= avail_in; | |
4043 | |
4044 png_ptr->zstream.next_in = buffer; | |
4045 png_ptr->zstream.avail_in = avail_in; | |
4046 } | |
4047 | |
4048 /* And set up the output side. */ | |
4049 if (output != NULL) /* standard read */ | |
4050 { | |
4051 uInt out = ZLIB_IO_MAX; | |
4052 | |
4053 if (out > avail_out) | |
4054 out = (uInt)avail_out; | |
4055 | |
4056 avail_out -= out; | |
4057 png_ptr->zstream.avail_out = out; | |
4058 } | |
4059 | |
4060 else /* after last row, checking for end */ | |
4061 { | |
4062 png_ptr->zstream.next_out = tmpbuf; | |
4063 png_ptr->zstream.avail_out = (sizeof tmpbuf); | |
4064 } | |
4065 | |
4066 /* Use NO_FLUSH; this gives zlib the maximum opportunity to optimize the | |
4067 * process. If the LZ stream is truncated the sequential reader will | |
4068 * terminally damage the stream, above, by reading the chunk header of the | |
4069 * following chunk (it then exits with png_error). | |
4070 * | |
4071 * TODO: deal more elegantly with truncated IDAT lists. | |
4072 */ | |
4073 ret = PNG_INFLATE(png_ptr, Z_NO_FLUSH); | |
4074 | |
4075 /* Take the unconsumed output back. */ | |
4076 if (output != NULL) | |
4077 avail_out += png_ptr->zstream.avail_out; | |
4078 | |
4079 else /* avail_out counts the extra bytes */ | |
4080 avail_out += (sizeof tmpbuf) - png_ptr->zstream.avail_out; | |
4081 | |
4082 png_ptr->zstream.avail_out = 0; | |
4083 | |
4084 if (ret == Z_STREAM_END) | |
4085 { | |
4086 /* Do this for safety; we won't read any more into this row. */ | |
4087 png_ptr->zstream.next_out = NULL; | |
4088 | |
4089 png_ptr->mode |= PNG_AFTER_IDAT; | |
4090 png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED; | |
4091 | |
4092 if (png_ptr->zstream.avail_in > 0 || png_ptr->idat_size > 0) | |
4093 png_chunk_benign_error(png_ptr, "Extra compressed data"); | |
4094 break; | |
4095 } | |
4096 | |
4097 if (ret != Z_OK) | |
4098 { | |
4099 png_zstream_error(png_ptr, ret); | |
4100 | |
4101 if (output != NULL) | |
4102 png_chunk_error(png_ptr, png_ptr->zstream.msg); | |
4103 | |
4104 else /* checking */ | |
4105 { | |
4106 png_chunk_benign_error(png_ptr, png_ptr->zstream.msg); | |
4107 return; | |
4108 } | |
4109 } | |
4110 } while (avail_out > 0); | |
4111 | |
4112 if (avail_out > 0) | |
4113 { | |
4114 /* The stream ended before the image; this is the same as too few IDATs so | |
4115 * should be handled the same way. | |
4116 */ | |
4117 if (output != NULL) | |
4118 png_error(png_ptr, "Not enough image data"); | |
4119 | |
4120 else /* the deflate stream contained extra data */ | |
4121 png_chunk_benign_error(png_ptr, "Too much image data"); | |
4122 } | |
4123 } | |
4124 | |
4125 void /* PRIVATE */ | |
4126 png_read_finish_IDAT(png_structrp png_ptr) | |
4127 { | |
4128 /* We don't need any more data and the stream should have ended, however the | |
4129 * LZ end code may actually not have been processed. In this case we must | |
4130 * read it otherwise stray unread IDAT data or, more likely, an IDAT chunk | |
4131 * may still remain to be consumed. | |
4132 */ | |
4133 if ((png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0) | |
4134 { | |
4135 /* The NULL causes png_read_IDAT_data to swallow any remaining bytes in | |
4136 * the compressed stream, but the stream may be damaged too, so even after | |
4137 * this call we may need to terminate the zstream ownership. | |
4138 */ | |
4139 png_read_IDAT_data(png_ptr, NULL, 0); | |
4140 png_ptr->zstream.next_out = NULL; /* safety */ | |
4141 | |
4142 /* Now clear everything out for safety; the following may not have been | |
4143 * done. | |
4144 */ | |
4145 if ((png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0) | |
4146 { | |
4147 png_ptr->mode |= PNG_AFTER_IDAT; | |
4148 png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED; | |
4149 } | |
4150 } | |
4151 | |
4152 /* If the zstream has not been released do it now *and* terminate the reading | |
4153 * of the final IDAT chunk. | |
4154 */ | |
4155 if (png_ptr->zowner == png_IDAT) | |
4156 { | |
4157 /* Always do this; the pointers otherwise point into the read buffer. */ | |
4158 png_ptr->zstream.next_in = NULL; | |
4159 png_ptr->zstream.avail_in = 0; | |
4160 | |
4161 /* Now we no longer own the zstream. */ | |
4162 png_ptr->zowner = 0; | |
4163 | |
4164 /* The slightly weird semantics of the sequential IDAT reading is that we | |
4165 * are always in or at the end of an IDAT chunk, so we always need to do a | |
4166 * crc_finish here. If idat_size is non-zero we also need to read the | |
4167 * spurious bytes at the end of the chunk now. | |
4168 */ | |
4169 (void)png_crc_finish(png_ptr, png_ptr->idat_size); | |
4170 } | |
4171 } | |
4172 | |
4173 void /* PRIVATE */ | |
4174 png_read_finish_row(png_structrp png_ptr) | |
4175 { | |
4176 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ | |
4177 | |
4178 /* Start of interlace block */ | |
4179 static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0}; | |
4180 | |
4181 /* Offset to next interlace block */ | |
4182 static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1}; | |
4183 | |
4184 /* Start of interlace block in the y direction */ | |
4185 static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1}; | |
4186 | |
4187 /* Offset to next interlace block in the y direction */ | |
4188 static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2}; | |
4189 | |
4190 png_debug(1, "in png_read_finish_row"); | |
4191 png_ptr->row_number++; | |
4192 if (png_ptr->row_number < png_ptr->num_rows) | |
4193 return; | |
4194 | |
4195 if (png_ptr->interlaced != 0) | |
4196 { | |
4197 png_ptr->row_number = 0; | |
4198 | |
4199 /* TO DO: don't do this if prev_row isn't needed (requires | |
4200 * read-ahead of the next row's filter byte. | |
4201 */ | |
4202 memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1); | |
4203 | |
4204 do | |
4205 { | |
4206 png_ptr->pass++; | |
4207 | |
4208 if (png_ptr->pass >= 7) | |
4209 break; | |
4210 | |
4211 png_ptr->iwidth = (png_ptr->width + | |
4212 png_pass_inc[png_ptr->pass] - 1 - | |
4213 png_pass_start[png_ptr->pass]) / | |
4214 png_pass_inc[png_ptr->pass]; | |
4215 | |
4216 if ((png_ptr->transformations & PNG_INTERLACE) == 0) | |
4217 { | |
4218 png_ptr->num_rows = (png_ptr->height + | |
4219 png_pass_yinc[png_ptr->pass] - 1 - | |
4220 png_pass_ystart[png_ptr->pass]) / | |
4221 png_pass_yinc[png_ptr->pass]; | |
4222 } | |
4223 | |
4224 else /* if (png_ptr->transformations & PNG_INTERLACE) */ | |
4225 break; /* libpng deinterlacing sees every row */ | |
4226 | |
4227 } while (png_ptr->num_rows == 0 || png_ptr->iwidth == 0); | |
4228 | |
4229 if (png_ptr->pass < 7) | |
4230 return; | |
4231 } | |
4232 | |
4233 /* Here after at the end of the last row of the last pass. */ | |
4234 png_read_finish_IDAT(png_ptr); | |
4235 } | |
4236 #endif /* SEQUENTIAL_READ */ | |
4237 | |
4238 void /* PRIVATE */ | |
4239 png_read_start_row(png_structrp png_ptr) | |
4240 { | |
4241 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ | |
4242 | |
4243 /* Start of interlace block */ | |
4244 static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0}; | |
4245 | |
4246 /* Offset to next interlace block */ | |
4247 static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1}; | |
4248 | |
4249 /* Start of interlace block in the y direction */ | |
4250 static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1}; | |
4251 | |
4252 /* Offset to next interlace block in the y direction */ | |
4253 static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2}; | |
4254 | |
4255 int max_pixel_depth; | |
4256 png_size_t row_bytes; | |
4257 | |
4258 png_debug(1, "in png_read_start_row"); | |
4259 | |
4260 #ifdef PNG_READ_TRANSFORMS_SUPPORTED | |
4261 png_init_read_transformations(png_ptr); | |
4262 #endif | |
4263 if (png_ptr->interlaced != 0) | |
4264 { | |
4265 if ((png_ptr->transformations & PNG_INTERLACE) == 0) | |
4266 png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 - | |
4267 png_pass_ystart[0]) / png_pass_yinc[0]; | |
4268 | |
4269 else | |
4270 png_ptr->num_rows = png_ptr->height; | |
4271 | |
4272 png_ptr->iwidth = (png_ptr->width + | |
4273 png_pass_inc[png_ptr->pass] - 1 - | |
4274 png_pass_start[png_ptr->pass]) / | |
4275 png_pass_inc[png_ptr->pass]; | |
4276 } | |
4277 | |
4278 else | |
4279 { | |
4280 png_ptr->num_rows = png_ptr->height; | |
4281 png_ptr->iwidth = png_ptr->width; | |
4282 } | |
4283 | |
4284 max_pixel_depth = png_ptr->pixel_depth; | |
4285 | |
4286 /* WARNING: * png_read_transform_info (pngrtran.c) performs a simpler set of | |
4287 * calculations to calculate the final pixel depth, then | |
4288 * png_do_read_transforms actually does the transforms. This means that the | |
4289 * code which effectively calculates this value is actually repeated in three | |
4290 * separate places. They must all match. Innocent changes to the order of | |
4291 * transformations can and will break libpng in a way that causes memory | |
4292 * overwrites. | |
4293 * | |
4294 * TODO: fix this. | |
4295 */ | |
4296 #ifdef PNG_READ_PACK_SUPPORTED | |
4297 if ((png_ptr->transformations & PNG_PACK) != 0 && png_ptr->bit_depth < 8) | |
4298 max_pixel_depth = 8; | |
4299 #endif | |
4300 | |
4301 #ifdef PNG_READ_EXPAND_SUPPORTED | |
4302 if ((png_ptr->transformations & PNG_EXPAND) != 0) | |
4303 { | |
4304 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) | |
4305 { | |
4306 if (png_ptr->num_trans != 0) | |
4307 max_pixel_depth = 32; | |
4308 | |
4309 else | |
4310 max_pixel_depth = 24; | |
4311 } | |
4312 | |
4313 else if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY) | |
4314 { | |
4315 if (max_pixel_depth < 8) | |
4316 max_pixel_depth = 8; | |
4317 | |
4318 if (png_ptr->num_trans != 0) | |
4319 max_pixel_depth *= 2; | |
4320 } | |
4321 | |
4322 else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB) | |
4323 { | |
4324 if (png_ptr->num_trans != 0) | |
4325 { | |
4326 max_pixel_depth *= 4; | |
4327 max_pixel_depth /= 3; | |
4328 } | |
4329 } | |
4330 } | |
4331 #endif | |
4332 | |
4333 #ifdef PNG_READ_EXPAND_16_SUPPORTED | |
4334 if ((png_ptr->transformations & PNG_EXPAND_16) != 0) | |
4335 { | |
4336 # ifdef PNG_READ_EXPAND_SUPPORTED | |
4337 /* In fact it is an error if it isn't supported, but checking is | |
4338 * the safe way. | |
4339 */ | |
4340 if ((png_ptr->transformations & PNG_EXPAND) != 0) | |
4341 { | |
4342 if (png_ptr->bit_depth < 16) | |
4343 max_pixel_depth *= 2; | |
4344 } | |
4345 else | |
4346 # endif | |
4347 png_ptr->transformations &= ~PNG_EXPAND_16; | |
4348 } | |
4349 #endif | |
4350 | |
4351 #ifdef PNG_READ_FILLER_SUPPORTED | |
4352 if ((png_ptr->transformations & (PNG_FILLER)) != 0) | |
4353 { | |
4354 if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY) | |
4355 { | |
4356 if (max_pixel_depth <= 8) | |
4357 max_pixel_depth = 16; | |
4358 | |
4359 else | |
4360 max_pixel_depth = 32; | |
4361 } | |
4362 | |
4363 else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB || | |
4364 png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) | |
4365 { | |
4366 if (max_pixel_depth <= 32) | |
4367 max_pixel_depth = 32; | |
4368 | |
4369 else | |
4370 max_pixel_depth = 64; | |
4371 } | |
4372 } | |
4373 #endif | |
4374 | |
4375 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED | |
4376 if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0) | |
4377 { | |
4378 if ( | |
4379 #ifdef PNG_READ_EXPAND_SUPPORTED | |
4380 (png_ptr->num_trans != 0 && | |
4381 (png_ptr->transformations & PNG_EXPAND) != 0) || | |
4382 #endif | |
4383 #ifdef PNG_READ_FILLER_SUPPORTED | |
4384 (png_ptr->transformations & (PNG_FILLER)) != 0 || | |
4385 #endif | |
4386 png_ptr->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) | |
4387 { | |
4388 if (max_pixel_depth <= 16) | |
4389 max_pixel_depth = 32; | |
4390 | |
4391 else | |
4392 max_pixel_depth = 64; | |
4393 } | |
4394 | |
4395 else | |
4396 { | |
4397 if (max_pixel_depth <= 8) | |
4398 { | |
4399 if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA) | |
4400 max_pixel_depth = 32; | |
4401 | |
4402 else | |
4403 max_pixel_depth = 24; | |
4404 } | |
4405 | |
4406 else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA) | |
4407 max_pixel_depth = 64; | |
4408 | |
4409 else | |
4410 max_pixel_depth = 48; | |
4411 } | |
4412 } | |
4413 #endif | |
4414 | |
4415 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) && \ | |
4416 defined(PNG_USER_TRANSFORM_PTR_SUPPORTED) | |
4417 if ((png_ptr->transformations & PNG_USER_TRANSFORM) != 0) | |
4418 { | |
4419 int user_pixel_depth = png_ptr->user_transform_depth * | |
4420 png_ptr->user_transform_channels; | |
4421 | |
4422 if (user_pixel_depth > max_pixel_depth) | |
4423 max_pixel_depth = user_pixel_depth; | |
4424 } | |
4425 #endif | |
4426 | |
4427 /* This value is stored in png_struct and double checked in the row read | |
4428 * code. | |
4429 */ | |
4430 png_ptr->maximum_pixel_depth = (png_byte)max_pixel_depth; | |
4431 png_ptr->transformed_pixel_depth = 0; /* calculated on demand */ | |
4432 | |
4433 /* Align the width on the next larger 8 pixels. Mainly used | |
4434 * for interlacing | |
4435 */ | |
4436 row_bytes = ((png_ptr->width + 7) & ~((png_uint_32)7)); | |
4437 /* Calculate the maximum bytes needed, adding a byte and a pixel | |
4438 * for safety's sake | |
4439 */ | |
4440 row_bytes = PNG_ROWBYTES(max_pixel_depth, row_bytes) + | |
4441 1 + ((max_pixel_depth + 7) >> 3); | |
4442 | |
4443 #ifdef PNG_MAX_MALLOC_64K | |
4444 if (row_bytes > (png_uint_32)65536L) | |
4445 png_error(png_ptr, "This image requires a row greater than 64KB"); | |
4446 #endif | |
4447 | |
4448 if (row_bytes + 48 > png_ptr->old_big_row_buf_size) | |
4449 { | |
4450 png_free(png_ptr, png_ptr->big_row_buf); | |
4451 png_free(png_ptr, png_ptr->big_prev_row); | |
4452 | |
4453 if (png_ptr->interlaced != 0) | |
4454 png_ptr->big_row_buf = (png_bytep)png_calloc(png_ptr, | |
4455 row_bytes + 48); | |
4456 | |
4457 else | |
4458 png_ptr->big_row_buf = (png_bytep)png_malloc(png_ptr, row_bytes + 48); | |
4459 | |
4460 png_ptr->big_prev_row = (png_bytep)png_malloc(png_ptr, row_bytes + 48); | |
4461 | |
4462 #ifdef PNG_ALIGNED_MEMORY_SUPPORTED | |
4463 /* Use 16-byte aligned memory for row_buf with at least 16 bytes | |
4464 * of padding before and after row_buf; treat prev_row similarly. | |
4465 * NOTE: the alignment is to the start of the pixels, one beyond the start | |
4466 * of the buffer, because of the filter byte. Prior to libpng 1.5.6 this | |
4467 * was incorrect; the filter byte was aligned, which had the exact | |
4468 * opposite effect of that intended. | |
4469 */ | |
4470 { | |
4471 png_bytep temp = png_ptr->big_row_buf + 32; | |
4472 int extra = (int)((temp - (png_bytep)0) & 0x0f); | |
4473 png_ptr->row_buf = temp - extra - 1/*filter byte*/; | |
4474 | |
4475 temp = png_ptr->big_prev_row + 32; | |
4476 extra = (int)((temp - (png_bytep)0) & 0x0f); | |
4477 png_ptr->prev_row = temp - extra - 1/*filter byte*/; | |
4478 } | |
4479 | |
4480 #else | |
4481 /* Use 31 bytes of padding before and 17 bytes after row_buf. */ | |
4482 png_ptr->row_buf = png_ptr->big_row_buf + 31; | |
4483 png_ptr->prev_row = png_ptr->big_prev_row + 31; | |
4484 #endif | |
4485 png_ptr->old_big_row_buf_size = row_bytes + 48; | |
4486 } | |
4487 | |
4488 #ifdef PNG_MAX_MALLOC_64K | |
4489 if (png_ptr->rowbytes > 65535) | |
4490 png_error(png_ptr, "This image requires a row greater than 64KB"); | |
4491 | |
4492 #endif | |
4493 if (png_ptr->rowbytes > (PNG_SIZE_MAX - 1)) | |
4494 png_error(png_ptr, "Row has too many bytes to allocate in memory"); | |
4495 | |
4496 memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1); | |
4497 | |
4498 png_debug1(3, "width = %u,", png_ptr->width); | |
4499 png_debug1(3, "height = %u,", png_ptr->height); | |
4500 png_debug1(3, "iwidth = %u,", png_ptr->iwidth); | |
4501 png_debug1(3, "num_rows = %u,", png_ptr->num_rows); | |
4502 png_debug1(3, "rowbytes = %lu,", (unsigned long)png_ptr->rowbytes); | |
4503 png_debug1(3, "irowbytes = %lu", | |
4504 (unsigned long)PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->iwidth) + 1); | |
4505 | |
4506 /* The sequential reader needs a buffer for IDAT, but the progressive reader | |
4507 * does not, so free the read buffer now regardless; the sequential reader | |
4508 * reallocates it on demand. | |
4509 */ | |
4510 if (png_ptr->read_buffer != 0) | |
4511 { | |
4512 png_bytep buffer = png_ptr->read_buffer; | |
4513 | |
4514 png_ptr->read_buffer_size = 0; | |
4515 png_ptr->read_buffer = NULL; | |
4516 png_free(png_ptr, buffer); | |
4517 } | |
4518 | |
4519 /* Finally claim the zstream for the inflate of the IDAT data, use the bits | |
4520 * value from the stream (note that this will result in a fatal error if the | |
4521 * IDAT stream has a bogus deflate header window_bits value, but this should | |
4522 * not be happening any longer!) | |
4523 */ | |
4524 if (png_inflate_claim(png_ptr, png_IDAT) != Z_OK) | |
4525 png_error(png_ptr, png_ptr->zstream.msg); | |
4526 | |
4527 png_ptr->flags |= PNG_FLAG_ROW_INIT; | |
4528 } | |
4529 #endif /* READ */ | |
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