1 /*
2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation. Oracle designates this
7 * particular file as subject to the "Classpath" exception as provided
8 * by Oracle in the LICENSE file that accompanied this code.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 */
24
25 /* pngrutil.c - utilities to read a PNG file
26 *
27 * This file is available under and governed by the GNU General Public
28 * License version 2 only, as published by the Free Software Foundation.
29 * However, the following notice accompanied the original version of this
30 * file and, per its terms, should not be removed:
31 *
32 * Last changed in libpng 1.6.27 [January 5, 2017]
33 * Copyright (c) 1998-2002,2004,2006-2016 Glenn Randers-Pehrson
34 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
35 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
36 *
37 * This code is released under the libpng license.
38 * For conditions of distribution and use, see the disclaimer
39 * and license in png.h
40 *
41 * This file contains routines that are only called from within
42 * libpng itself during the course of reading an image.
43 */
44
45 #include "pngpriv.h"
46
47 #ifdef PNG_READ_SUPPORTED
48
49 png_uint_32 PNGAPI
50 png_get_uint_31(png_const_structrp png_ptr, png_const_bytep buf)
51 {
52 png_uint_32 uval = png_get_uint_32(buf);
53
54 if (uval > PNG_UINT_31_MAX)
55 png_error(png_ptr, "PNG unsigned integer out of range");
56
57 return (uval);
58 }
59
60 #if defined(PNG_READ_gAMA_SUPPORTED) || defined(PNG_READ_cHRM_SUPPORTED)
61 /* The following is a variation on the above for use with the fixed
62 * point values used for gAMA and cHRM. Instead of png_error it
63 * issues a warning and returns (-1) - an invalid value because both
64 * gAMA and cHRM use *unsigned* integers for fixed point values.
65 */
66 #define PNG_FIXED_ERROR (-1)
67
68 static png_fixed_point /* PRIVATE */
69 png_get_fixed_point(png_structrp png_ptr, png_const_bytep buf)
70 {
71 png_uint_32 uval = png_get_uint_32(buf);
72
73 if (uval <= PNG_UINT_31_MAX)
74 return (png_fixed_point)uval; /* known to be in range */
75
76 /* The caller can turn off the warning by passing NULL. */
77 if (png_ptr != NULL)
78 png_warning(png_ptr, "PNG fixed point integer out of range");
79
80 return PNG_FIXED_ERROR;
81 }
82 #endif
83
84 #ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED
85 /* NOTE: the read macros will obscure these definitions, so that if
86 * PNG_USE_READ_MACROS is set the library will not use them internally,
87 * but the APIs will still be available externally.
88 *
89 * The parentheses around "PNGAPI function_name" in the following three
90 * functions are necessary because they allow the macros to co-exist with
91 * these (unused but exported) functions.
92 */
93
94 /* Grab an unsigned 32-bit integer from a buffer in big-endian format. */
95 png_uint_32 (PNGAPI
96 png_get_uint_32)(png_const_bytep buf)
97 {
98 png_uint_32 uval =
99 ((png_uint_32)(*(buf )) << 24) +
100 ((png_uint_32)(*(buf + 1)) << 16) +
101 ((png_uint_32)(*(buf + 2)) << 8) +
102 ((png_uint_32)(*(buf + 3)) ) ;
103
104 return uval;
105 }
106
107 /* Grab a signed 32-bit integer from a buffer in big-endian format. The
108 * data is stored in the PNG file in two's complement format and there
109 * is no guarantee that a 'png_int_32' is exactly 32 bits, therefore
110 * the following code does a two's complement to native conversion.
111 */
112 png_int_32 (PNGAPI
113 png_get_int_32)(png_const_bytep buf)
114 {
115 png_uint_32 uval = png_get_uint_32(buf);
116 if ((uval & 0x80000000) == 0) /* non-negative */
117 return (png_int_32)uval;
118
119 uval = (uval ^ 0xffffffff) + 1; /* 2's complement: -x = ~x+1 */
120 if ((uval & 0x80000000) == 0) /* no overflow */
121 return -(png_int_32)uval;
122 /* The following has to be safe; this function only gets called on PNG data
123 * and if we get here that data is invalid. 0 is the most safe value and
124 * if not then an attacker would surely just generate a PNG with 0 instead.
125 */
126 return 0;
127 }
128
129 /* Grab an unsigned 16-bit integer from a buffer in big-endian format. */
130 png_uint_16 (PNGAPI
131 png_get_uint_16)(png_const_bytep buf)
132 {
133 /* ANSI-C requires an int value to accomodate at least 16 bits so this
134 * works and allows the compiler not to worry about possible narrowing
135 * on 32-bit systems. (Pre-ANSI systems did not make integers smaller
136 * than 16 bits either.)
137 */
138 unsigned int val =
139 ((unsigned int)(*buf) << 8) +
140 ((unsigned int)(*(buf + 1)));
141
142 return (png_uint_16)val;
143 }
144
145 #endif /* READ_INT_FUNCTIONS */
146
147 /* Read and check the PNG file signature */
148 void /* PRIVATE */
149 png_read_sig(png_structrp png_ptr, png_inforp info_ptr)
150 {
151 png_size_t num_checked, num_to_check;
152
153 /* Exit if the user application does not expect a signature. */
154 if (png_ptr->sig_bytes >= 8)
155 return;
156
157 num_checked = png_ptr->sig_bytes;
158 num_to_check = 8 - num_checked;
159
160 #ifdef PNG_IO_STATE_SUPPORTED
161 png_ptr->io_state = PNG_IO_READING | PNG_IO_SIGNATURE;
162 #endif
163
164 /* The signature must be serialized in a single I/O call. */
165 png_read_data(png_ptr, &(info_ptr->signature[num_checked]), num_to_check);
166 png_ptr->sig_bytes = 8;
167
168 if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check) != 0)
169 {
170 if (num_checked < 4 &&
171 png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))
172 png_error(png_ptr, "Not a PNG file");
173 else
174 png_error(png_ptr, "PNG file corrupted by ASCII conversion");
175 }
176 if (num_checked < 3)
177 png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
178 }
179
180 /* Read the chunk header (length + type name).
181 * Put the type name into png_ptr->chunk_name, and return the length.
182 */
183 png_uint_32 /* PRIVATE */
184 png_read_chunk_header(png_structrp png_ptr)
185 {
186 png_byte buf[8];
187 png_uint_32 length;
188
189 #ifdef PNG_IO_STATE_SUPPORTED
190 png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_HDR;
191 #endif
192
193 /* Read the length and the chunk name.
194 * This must be performed in a single I/O call.
195 */
196 png_read_data(png_ptr, buf, 8);
197 length = png_get_uint_31(png_ptr, buf);
198
199 /* Put the chunk name into png_ptr->chunk_name. */
200 png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(buf+4);
201
202 png_debug2(0, "Reading %lx chunk, length = %lu",
203 (unsigned long)png_ptr->chunk_name, (unsigned long)length);
204
205 /* Reset the crc and run it over the chunk name. */
206 png_reset_crc(png_ptr);
207 png_calculate_crc(png_ptr, buf + 4, 4);
208
209 /* Check to see if chunk name is valid. */
210 png_check_chunk_name(png_ptr, png_ptr->chunk_name);
211
212 #ifdef PNG_IO_STATE_SUPPORTED
213 png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_DATA;
214 #endif
215
216 return length;
217 }
218
219 /* Read data, and (optionally) run it through the CRC. */
220 void /* PRIVATE */
221 png_crc_read(png_structrp png_ptr, png_bytep buf, png_uint_32 length)
222 {
223 if (png_ptr == NULL)
224 return;
225
226 png_read_data(png_ptr, buf, length);
227 png_calculate_crc(png_ptr, buf, length);
228 }
229
230 /* Optionally skip data and then check the CRC. Depending on whether we
231 * are reading an ancillary or critical chunk, and how the program has set
232 * things up, we may calculate the CRC on the data and print a message.
233 * Returns '1' if there was a CRC error, '0' otherwise.
234 */
235 int /* PRIVATE */
236 png_crc_finish(png_structrp png_ptr, png_uint_32 skip)
237 {
238 /* The size of the local buffer for inflate is a good guess as to a
239 * reasonable size to use for buffering reads from the application.
240 */
241 while (skip > 0)
242 {
243 png_uint_32 len;
244 png_byte tmpbuf[PNG_INFLATE_BUF_SIZE];
245
246 len = (sizeof tmpbuf);
247 if (len > skip)
248 len = skip;
249 skip -= len;
250
251 png_crc_read(png_ptr, tmpbuf, len);
252 }
253
254 if (png_crc_error(png_ptr) != 0)
255 {
256 if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name) != 0 ?
257 (png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) == 0 :
258 (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_USE) != 0)
259 {
260 png_chunk_warning(png_ptr, "CRC error");
261 }
262
263 else
264 png_chunk_error(png_ptr, "CRC error");
265
266 return (1);
267 }
268
269 return (0);
270 }
271
272 /* Compare the CRC stored in the PNG file with that calculated by libpng from
273 * the data it has read thus far.
274 */
275 int /* PRIVATE */
276 png_crc_error(png_structrp png_ptr)
277 {
278 png_byte crc_bytes[4];
279 png_uint_32 crc;
280 int need_crc = 1;
281
282 if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name) != 0)
283 {
284 if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) ==
285 (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN))
286 need_crc = 0;
287 }
288
289 else /* critical */
290 {
291 if ((png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE) != 0)
292 need_crc = 0;
293 }
294
295 #ifdef PNG_IO_STATE_SUPPORTED
296 png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_CRC;
297 #endif
298
299 /* The chunk CRC must be serialized in a single I/O call. */
300 png_read_data(png_ptr, crc_bytes, 4);
301
302 if (need_crc != 0)
303 {
304 crc = png_get_uint_32(crc_bytes);
305 return ((int)(crc != png_ptr->crc));
306 }
307
308 else
309 return (0);
310 }
311
312 #if defined(PNG_READ_iCCP_SUPPORTED) || defined(PNG_READ_iTXt_SUPPORTED) ||\
313 defined(PNG_READ_pCAL_SUPPORTED) || defined(PNG_READ_sCAL_SUPPORTED) ||\
314 defined(PNG_READ_sPLT_SUPPORTED) || defined(PNG_READ_tEXt_SUPPORTED) ||\
315 defined(PNG_READ_zTXt_SUPPORTED) || defined(PNG_SEQUENTIAL_READ_SUPPORTED)
316 /* Manage the read buffer; this simply reallocates the buffer if it is not small
317 * enough (or if it is not allocated). The routine returns a pointer to the
318 * buffer; if an error occurs and 'warn' is set the routine returns NULL, else
319 * it will call png_error (via png_malloc) on failure. (warn == 2 means
320 * 'silent').
321 */
322 static png_bytep
323 png_read_buffer(png_structrp png_ptr, png_alloc_size_t new_size, int warn)
324 {
325 png_bytep buffer = png_ptr->read_buffer;
326
327 if (buffer != NULL && new_size > png_ptr->read_buffer_size)
328 {
329 png_ptr->read_buffer = NULL;
330 png_ptr->read_buffer = NULL;
331 png_ptr->read_buffer_size = 0;
332 png_free(png_ptr, buffer);
333 buffer = NULL;
334 }
335
336 if (buffer == NULL)
337 {
338 buffer = png_voidcast(png_bytep, png_malloc_base(png_ptr, new_size));
339
340 if (buffer != NULL)
341 {
342 png_ptr->read_buffer = buffer;
343 png_ptr->read_buffer_size = new_size;
344 }
345
346 else if (warn < 2) /* else silent */
347 {
348 if (warn != 0)
349 png_chunk_warning(png_ptr, "insufficient memory to read chunk");
350
351 else
352 png_chunk_error(png_ptr, "insufficient memory to read chunk");
353 }
354 }
355
356 return buffer;
357 }
358 #endif /* READ_iCCP|iTXt|pCAL|sCAL|sPLT|tEXt|zTXt|SEQUENTIAL_READ */
359
360 /* png_inflate_claim: claim the zstream for some nefarious purpose that involves
361 * decompression. Returns Z_OK on success, else a zlib error code. It checks
362 * the owner but, in final release builds, just issues a warning if some other
363 * chunk apparently owns the stream. Prior to release it does a png_error.
364 */
365 static int
366 png_inflate_claim(png_structrp png_ptr, png_uint_32 owner)
367 {
368 if (png_ptr->zowner != 0)
369 {
370 char msg[64];
371
372 PNG_STRING_FROM_CHUNK(msg, png_ptr->zowner);
373 /* So the message that results is "<chunk> using zstream"; this is an
374 * internal error, but is very useful for debugging. i18n requirements
375 * are minimal.
376 */
377 (void)png_safecat(msg, (sizeof msg), 4, " using zstream");
378 #if PNG_RELEASE_BUILD
379 png_chunk_warning(png_ptr, msg);
380 png_ptr->zowner = 0;
381 #else
382 png_chunk_error(png_ptr, msg);
383 #endif
384 }
385
386 /* Implementation note: unlike 'png_deflate_claim' this internal function
387 * does not take the size of the data as an argument. Some efficiency could
388 * be gained by using this when it is known *if* the zlib stream itself does
389 * not record the number; however, this is an illusion: the original writer
390 * of the PNG may have selected a lower window size, and we really must
391 * follow that because, for systems with with limited capabilities, we
392 * would otherwise reject the application's attempts to use a smaller window
393 * size (zlib doesn't have an interface to say "this or lower"!).
394 *
395 * inflateReset2 was added to zlib 1.2.4; before this the window could not be
396 * reset, therefore it is necessary to always allocate the maximum window
397 * size with earlier zlibs just in case later compressed chunks need it.
398 */
399 {
400 int ret; /* zlib return code */
401 #if ZLIB_VERNUM >= 0x1240
402 int window_bits = 0;
403
404 # if defined(PNG_SET_OPTION_SUPPORTED) && defined(PNG_MAXIMUM_INFLATE_WINDOW)
405 if (((png_ptr->options >> PNG_MAXIMUM_INFLATE_WINDOW) & 3) ==
406 PNG_OPTION_ON)
407 {
408 window_bits = 15;
409 png_ptr->zstream_start = 0; /* fixed window size */
410 }
411
412 else
413 {
414 png_ptr->zstream_start = 1;
415 }
416 # endif
417
418 #endif /* ZLIB_VERNUM >= 0x1240 */
419
420 /* Set this for safety, just in case the previous owner left pointers to
421 * memory allocations.
422 */
423 png_ptr->zstream.next_in = NULL;
424 png_ptr->zstream.avail_in = 0;
425 png_ptr->zstream.next_out = NULL;
426 png_ptr->zstream.avail_out = 0;
427
428 if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0)
429 {
430 #if ZLIB_VERNUM >= 0x1240
431 ret = inflateReset2(&png_ptr->zstream, window_bits);
432 #else
433 ret = inflateReset(&png_ptr->zstream);
434 #endif
435 }
436
437 else
438 {
439 #if ZLIB_VERNUM >= 0x1240
440 ret = inflateInit2(&png_ptr->zstream, window_bits);
441 #else
442 ret = inflateInit(&png_ptr->zstream);
443 #endif
444
445 if (ret == Z_OK)
446 png_ptr->flags |= PNG_FLAG_ZSTREAM_INITIALIZED;
447 }
448
449 #if ZLIB_VERNUM >= 0x1281 && \
450 defined(PNG_SET_OPTION_SUPPORTED) && defined(PNG_IGNORE_ADLER32)
451 if (((png_ptr->options >> PNG_IGNORE_ADLER32) & 3) == PNG_OPTION_ON)
452 /* Turn off validation of the ADLER32 checksum in IDAT chunks */
453 ret = inflateValidate(&png_ptr->zstream, 0);
454 #endif
455
456 if (ret == Z_OK)
457 png_ptr->zowner = owner;
458
459 else
460 png_zstream_error(png_ptr, ret);
461
462 return ret;
463 }
464
465 #ifdef window_bits
466 # undef window_bits
467 #endif
468 }
469
470 #if ZLIB_VERNUM >= 0x1240
471 /* Handle the start of the inflate stream if we called inflateInit2(strm,0);
472 * in this case some zlib versions skip validation of the CINFO field and, in
473 * certain circumstances, libpng may end up displaying an invalid image, in
474 * contrast to implementations that call zlib in the normal way (e.g. libpng
475 * 1.5).
476 */
477 int /* PRIVATE */
478 png_zlib_inflate(png_structrp png_ptr, int flush)
479 {
480 if (png_ptr->zstream_start && png_ptr->zstream.avail_in > 0)
481 {
482 if ((*png_ptr->zstream.next_in >> 4) > 7)
483 {
484 png_ptr->zstream.msg = "invalid window size (libpng)";
485 return Z_DATA_ERROR;
486 }
487
488 png_ptr->zstream_start = 0;
489 }
490
491 return inflate(&png_ptr->zstream, flush);
492 }
493 #endif /* Zlib >= 1.2.4 */
494
495 #ifdef PNG_READ_COMPRESSED_TEXT_SUPPORTED
496 #if defined(PNG_READ_zTXt_SUPPORTED) || defined (PNG_READ_iTXt_SUPPORTED)
497 /* png_inflate now returns zlib error codes including Z_OK and Z_STREAM_END to
498 * allow the caller to do multiple calls if required. If the 'finish' flag is
499 * set Z_FINISH will be passed to the final inflate() call and Z_STREAM_END must
500 * be returned or there has been a problem, otherwise Z_SYNC_FLUSH is used and
501 * Z_OK or Z_STREAM_END will be returned on success.
502 *
503 * The input and output sizes are updated to the actual amounts of data consumed
504 * or written, not the amount available (as in a z_stream). The data pointers
505 * are not changed, so the next input is (data+input_size) and the next
506 * available output is (output+output_size).
507 */
508 static int
509 png_inflate(png_structrp png_ptr, png_uint_32 owner, int finish,
510 /* INPUT: */ png_const_bytep input, png_uint_32p input_size_ptr,
511 /* OUTPUT: */ png_bytep output, png_alloc_size_t *output_size_ptr)
512 {
513 if (png_ptr->zowner == owner) /* Else not claimed */
514 {
515 int ret;
516 png_alloc_size_t avail_out = *output_size_ptr;
517 png_uint_32 avail_in = *input_size_ptr;
518
519 /* zlib can't necessarily handle more than 65535 bytes at once (i.e. it
520 * can't even necessarily handle 65536 bytes) because the type uInt is
521 * "16 bits or more". Consequently it is necessary to chunk the input to
522 * zlib. This code uses ZLIB_IO_MAX, from pngpriv.h, as the maximum (the
523 * maximum value that can be stored in a uInt.) It is possible to set
524 * ZLIB_IO_MAX to a lower value in pngpriv.h and this may sometimes have
525 * a performance advantage, because it reduces the amount of data accessed
526 * at each step and that may give the OS more time to page it in.
527 */
528 png_ptr->zstream.next_in = PNGZ_INPUT_CAST(input);
529 /* avail_in and avail_out are set below from 'size' */
530 png_ptr->zstream.avail_in = 0;
531 png_ptr->zstream.avail_out = 0;
532
533 /* Read directly into the output if it is available (this is set to
534 * a local buffer below if output is NULL).
535 */
536 if (output != NULL)
537 png_ptr->zstream.next_out = output;
538
539 do
540 {
541 uInt avail;
542 Byte local_buffer[PNG_INFLATE_BUF_SIZE];
543
544 /* zlib INPUT BUFFER */
545 /* The setting of 'avail_in' used to be outside the loop; by setting it
546 * inside it is possible to chunk the input to zlib and simply rely on
547 * zlib to advance the 'next_in' pointer. This allows arbitrary
548 * amounts of data to be passed through zlib at the unavoidable cost of
549 * requiring a window save (memcpy of up to 32768 output bytes)
550 * every ZLIB_IO_MAX input bytes.
551 */
552 avail_in += png_ptr->zstream.avail_in; /* not consumed last time */
553
554 avail = ZLIB_IO_MAX;
555
556 if (avail_in < avail)
557 avail = (uInt)avail_in; /* safe: < than ZLIB_IO_MAX */
558
559 avail_in -= avail;
560 png_ptr->zstream.avail_in = avail;
561
562 /* zlib OUTPUT BUFFER */
563 avail_out += png_ptr->zstream.avail_out; /* not written last time */
564
565 avail = ZLIB_IO_MAX; /* maximum zlib can process */
566
567 if (output == NULL)
568 {
569 /* Reset the output buffer each time round if output is NULL and
570 * make available the full buffer, up to 'remaining_space'
571 */
572 png_ptr->zstream.next_out = local_buffer;
573 if ((sizeof local_buffer) < avail)
574 avail = (sizeof local_buffer);
575 }
576
577 if (avail_out < avail)
578 avail = (uInt)avail_out; /* safe: < ZLIB_IO_MAX */
579
580 png_ptr->zstream.avail_out = avail;
581 avail_out -= avail;
582
583 /* zlib inflate call */
584 /* In fact 'avail_out' may be 0 at this point, that happens at the end
585 * of the read when the final LZ end code was not passed at the end of
586 * the previous chunk of input data. Tell zlib if we have reached the
587 * end of the output buffer.
588 */
589 ret = PNG_INFLATE(png_ptr, avail_out > 0 ? Z_NO_FLUSH :
590 (finish ? Z_FINISH : Z_SYNC_FLUSH));
591 } while (ret == Z_OK);
592
593 /* For safety kill the local buffer pointer now */
594 if (output == NULL)
595 png_ptr->zstream.next_out = NULL;
596
597 /* Claw back the 'size' and 'remaining_space' byte counts. */
598 avail_in += png_ptr->zstream.avail_in;
599 avail_out += png_ptr->zstream.avail_out;
600
601 /* Update the input and output sizes; the updated values are the amount
602 * consumed or written, effectively the inverse of what zlib uses.
603 */
604 if (avail_out > 0)
605 *output_size_ptr -= avail_out;
606
607 if (avail_in > 0)
608 *input_size_ptr -= avail_in;
609
610 /* Ensure png_ptr->zstream.msg is set (even in the success case!) */
611 png_zstream_error(png_ptr, ret);
612 return ret;
613 }
614
615 else
616 {
617 /* This is a bad internal error. The recovery assigns to the zstream msg
618 * pointer, which is not owned by the caller, but this is safe; it's only
619 * used on errors!
620 */
621 png_ptr->zstream.msg = PNGZ_MSG_CAST("zstream unclaimed");
622 return Z_STREAM_ERROR;
623 }
624 }
625
626 /*
627 * Decompress trailing data in a chunk. The assumption is that read_buffer
628 * points at an allocated area holding the contents of a chunk with a
629 * trailing compressed part. What we get back is an allocated area
630 * holding the original prefix part and an uncompressed version of the
631 * trailing part (the malloc area passed in is freed).
632 */
633 static int
634 png_decompress_chunk(png_structrp png_ptr,
635 png_uint_32 chunklength, png_uint_32 prefix_size,
636 png_alloc_size_t *newlength /* must be initialized to the maximum! */,
637 int terminate /*add a '\0' to the end of the uncompressed data*/)
638 {
639 /* TODO: implement different limits for different types of chunk.
640 *
641 * The caller supplies *newlength set to the maximum length of the
642 * uncompressed data, but this routine allocates space for the prefix and
643 * maybe a '\0' terminator too. We have to assume that 'prefix_size' is
644 * limited only by the maximum chunk size.
645 */
646 png_alloc_size_t limit = PNG_SIZE_MAX;
647
648 # ifdef PNG_SET_USER_LIMITS_SUPPORTED
649 if (png_ptr->user_chunk_malloc_max > 0 &&
650 png_ptr->user_chunk_malloc_max < limit)
651 limit = png_ptr->user_chunk_malloc_max;
652 # elif PNG_USER_CHUNK_MALLOC_MAX > 0
653 if (PNG_USER_CHUNK_MALLOC_MAX < limit)
654 limit = PNG_USER_CHUNK_MALLOC_MAX;
655 # endif
656
657 if (limit >= prefix_size + (terminate != 0))
658 {
659 int ret;
660
661 limit -= prefix_size + (terminate != 0);
662
663 if (limit < *newlength)
664 *newlength = limit;
665
666 /* Now try to claim the stream. */
667 ret = png_inflate_claim(png_ptr, png_ptr->chunk_name);
668
669 if (ret == Z_OK)
670 {
671 png_uint_32 lzsize = chunklength - prefix_size;
672
673 ret = png_inflate(png_ptr, png_ptr->chunk_name, 1/*finish*/,
674 /* input: */ png_ptr->read_buffer + prefix_size, &lzsize,
675 /* output: */ NULL, newlength);
676
677 if (ret == Z_STREAM_END)
678 {
679 /* Use 'inflateReset' here, not 'inflateReset2' because this
680 * preserves the previously decided window size (otherwise it would
681 * be necessary to store the previous window size.) In practice
682 * this doesn't matter anyway, because png_inflate will call inflate
683 * with Z_FINISH in almost all cases, so the window will not be
684 * maintained.
685 */
686 if (inflateReset(&png_ptr->zstream) == Z_OK)
687 {
688 /* Because of the limit checks above we know that the new,
689 * expanded, size will fit in a size_t (let alone an
690 * png_alloc_size_t). Use png_malloc_base here to avoid an
691 * extra OOM message.
692 */
693 png_alloc_size_t new_size = *newlength;
694 png_alloc_size_t buffer_size = prefix_size + new_size +
695 (terminate != 0);
696 png_bytep text = png_voidcast(png_bytep, png_malloc_base(png_ptr,
697 buffer_size));
698
699 if (text != NULL)
700 {
701 ret = png_inflate(png_ptr, png_ptr->chunk_name, 1/*finish*/,
702 png_ptr->read_buffer + prefix_size, &lzsize,
703 text + prefix_size, newlength);
704
705 if (ret == Z_STREAM_END)
706 {
707 if (new_size == *newlength)
708 {
709 if (terminate != 0)
710 text[prefix_size + *newlength] = 0;
711
712 if (prefix_size > 0)
713 memcpy(text, png_ptr->read_buffer, prefix_size);
714
715 {
716 png_bytep old_ptr = png_ptr->read_buffer;
717
718 png_ptr->read_buffer = text;
719 png_ptr->read_buffer_size = buffer_size;
720 text = old_ptr; /* freed below */
721 }
722 }
723
724 else
725 {
726 /* The size changed on the second read, there can be no
727 * guarantee that anything is correct at this point.
728 * The 'msg' pointer has been set to "unexpected end of
729 * LZ stream", which is fine, but return an error code
730 * that the caller won't accept.
731 */
732 ret = PNG_UNEXPECTED_ZLIB_RETURN;
733 }
734 }
735
736 else if (ret == Z_OK)
737 ret = PNG_UNEXPECTED_ZLIB_RETURN; /* for safety */
738
739 /* Free the text pointer (this is the old read_buffer on
740 * success)
741 */
742 png_free(png_ptr, text);
743
744 /* This really is very benign, but it's still an error because
745 * the extra space may otherwise be used as a Trojan Horse.
746 */
747 if (ret == Z_STREAM_END &&
748 chunklength - prefix_size != lzsize)
749 png_chunk_benign_error(png_ptr, "extra compressed data");
750 }
751
752 else
753 {
754 /* Out of memory allocating the buffer */
755 ret = Z_MEM_ERROR;
756 png_zstream_error(png_ptr, Z_MEM_ERROR);
757 }
758 }
759
760 else
761 {
762 /* inflateReset failed, store the error message */
763 png_zstream_error(png_ptr, ret);
764
765 if (ret == Z_STREAM_END)
766 ret = PNG_UNEXPECTED_ZLIB_RETURN;
767 }
768 }
769
770 else if (ret == Z_OK)
771 ret = PNG_UNEXPECTED_ZLIB_RETURN;
772
773 /* Release the claimed stream */
774 png_ptr->zowner = 0;
775 }
776
777 else /* the claim failed */ if (ret == Z_STREAM_END) /* impossible! */
778 ret = PNG_UNEXPECTED_ZLIB_RETURN;
779
780 return ret;
781 }
782
783 else
784 {
785 /* Application/configuration limits exceeded */
786 png_zstream_error(png_ptr, Z_MEM_ERROR);
787 return Z_MEM_ERROR;
788 }
789 }
790 #endif /* READ_zTXt || READ_iTXt */
791 #endif /* READ_COMPRESSED_TEXT */
792
793 #ifdef PNG_READ_iCCP_SUPPORTED
794 /* Perform a partial read and decompress, producing 'avail_out' bytes and
795 * reading from the current chunk as required.
796 */
797 static int
798 png_inflate_read(png_structrp png_ptr, png_bytep read_buffer, uInt read_size,
799 png_uint_32p chunk_bytes, png_bytep next_out, png_alloc_size_t *out_size,
800 int finish)
801 {
802 if (png_ptr->zowner == png_ptr->chunk_name)
803 {
804 int ret;
805
806 /* next_in and avail_in must have been initialized by the caller. */
807 png_ptr->zstream.next_out = next_out;
808 png_ptr->zstream.avail_out = 0; /* set in the loop */
809
810 do
811 {
812 if (png_ptr->zstream.avail_in == 0)
813 {
814 if (read_size > *chunk_bytes)
815 read_size = (uInt)*chunk_bytes;
816 *chunk_bytes -= read_size;
817
818 if (read_size > 0)
819 png_crc_read(png_ptr, read_buffer, read_size);
820
821 png_ptr->zstream.next_in = read_buffer;
822 png_ptr->zstream.avail_in = read_size;
823 }
824
825 if (png_ptr->zstream.avail_out == 0)
826 {
827 uInt avail = ZLIB_IO_MAX;
828 if (avail > *out_size)
829 avail = (uInt)*out_size;
830 *out_size -= avail;
831
832 png_ptr->zstream.avail_out = avail;
833 }
834
835 /* Use Z_SYNC_FLUSH when there is no more chunk data to ensure that all
836 * the available output is produced; this allows reading of truncated
837 * streams.
838 */
839 ret = PNG_INFLATE(png_ptr, *chunk_bytes > 0 ?
840 Z_NO_FLUSH : (finish ? Z_FINISH : Z_SYNC_FLUSH));
841 }
842 while (ret == Z_OK && (*out_size > 0 || png_ptr->zstream.avail_out > 0));
843
844 *out_size += png_ptr->zstream.avail_out;
845 png_ptr->zstream.avail_out = 0; /* Should not be required, but is safe */
846
847 /* Ensure the error message pointer is always set: */
848 png_zstream_error(png_ptr, ret);
849 return ret;
850 }
851
852 else
853 {
854 png_ptr->zstream.msg = PNGZ_MSG_CAST("zstream unclaimed");
855 return Z_STREAM_ERROR;
856 }
857 }
858 #endif /* READ_iCCP */
859
860 /* Read and check the IDHR chunk */
861
862 void /* PRIVATE */
863 png_handle_IHDR(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
864 {
865 png_byte buf[13];
866 png_uint_32 width, height;
867 int bit_depth, color_type, compression_type, filter_type;
868 int interlace_type;
869
870 png_debug(1, "in png_handle_IHDR");
871
872 if ((png_ptr->mode & PNG_HAVE_IHDR) != 0)
873 png_chunk_error(png_ptr, "out of place");
874
875 /* Check the length */
876 if (length != 13)
877 png_chunk_error(png_ptr, "invalid");
878
879 png_ptr->mode |= PNG_HAVE_IHDR;
880
881 png_crc_read(png_ptr, buf, 13);
882 png_crc_finish(png_ptr, 0);
883
884 width = png_get_uint_31(png_ptr, buf);
885 height = png_get_uint_31(png_ptr, buf + 4);
886 bit_depth = buf[8];
887 color_type = buf[9];
888 compression_type = buf[10];
889 filter_type = buf[11];
890 interlace_type = buf[12];
891
892 /* Set internal variables */
893 png_ptr->width = width;
894 png_ptr->height = height;
895 png_ptr->bit_depth = (png_byte)bit_depth;
896 png_ptr->interlaced = (png_byte)interlace_type;
897 png_ptr->color_type = (png_byte)color_type;
898 #ifdef PNG_MNG_FEATURES_SUPPORTED
899 png_ptr->filter_type = (png_byte)filter_type;
900 #endif
901 png_ptr->compression_type = (png_byte)compression_type;
902
903 /* Find number of channels */
904 switch (png_ptr->color_type)
905 {
906 default: /* invalid, png_set_IHDR calls png_error */
907 case PNG_COLOR_TYPE_GRAY:
908 case PNG_COLOR_TYPE_PALETTE:
909 png_ptr->channels = 1;
910 break;
911
912 case PNG_COLOR_TYPE_RGB:
913 png_ptr->channels = 3;
914 break;
915
916 case PNG_COLOR_TYPE_GRAY_ALPHA:
917 png_ptr->channels = 2;
918 break;
919
920 case PNG_COLOR_TYPE_RGB_ALPHA:
921 png_ptr->channels = 4;
922 break;
923 }
924
925 /* Set up other useful info */
926 png_ptr->pixel_depth = (png_byte)(png_ptr->bit_depth * png_ptr->channels);
927 png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->width);
928 png_debug1(3, "bit_depth = %d", png_ptr->bit_depth);
929 png_debug1(3, "channels = %d", png_ptr->channels);
930 png_debug1(3, "rowbytes = %lu", (unsigned long)png_ptr->rowbytes);
931 png_set_IHDR(png_ptr, info_ptr, width, height, bit_depth,
932 color_type, interlace_type, compression_type, filter_type);
933 }
934
935 /* Read and check the palette */
936 void /* PRIVATE */
937 png_handle_PLTE(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
938 {
939 png_color palette[PNG_MAX_PALETTE_LENGTH];
940 int max_palette_length, num, i;
941 #ifdef PNG_POINTER_INDEXING_SUPPORTED
942 png_colorp pal_ptr;
943 #endif
944
945 png_debug(1, "in png_handle_PLTE");
946
947 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
948 png_chunk_error(png_ptr, "missing IHDR");
949
950 /* Moved to before the 'after IDAT' check below because otherwise duplicate
951 * PLTE chunks are potentially ignored (the spec says there shall not be more
952 * than one PLTE, the error is not treated as benign, so this check trumps
953 * the requirement that PLTE appears before IDAT.)
954 */
955 else if ((png_ptr->mode & PNG_HAVE_PLTE) != 0)
956 png_chunk_error(png_ptr, "duplicate");
957
958 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
959 {
960 /* This is benign because the non-benign error happened before, when an
961 * IDAT was encountered in a color-mapped image with no PLTE.
962 */
963 png_crc_finish(png_ptr, length);
964 png_chunk_benign_error(png_ptr, "out of place");
965 return;
966 }
967
968 png_ptr->mode |= PNG_HAVE_PLTE;
969
970 if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0)
971 {
972 png_crc_finish(png_ptr, length);
973 png_chunk_benign_error(png_ptr, "ignored in grayscale PNG");
974 return;
975 }
976
977 #ifndef PNG_READ_OPT_PLTE_SUPPORTED
978 if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
979 {
980 png_crc_finish(png_ptr, length);
981 return;
982 }
983 #endif
984
985 if (length > 3*PNG_MAX_PALETTE_LENGTH || length % 3)
986 {
987 png_crc_finish(png_ptr, length);
988
989 if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
990 png_chunk_benign_error(png_ptr, "invalid");
991
992 else
993 png_chunk_error(png_ptr, "invalid");
994
995 return;
996 }
997
998 /* The cast is safe because 'length' is less than 3*PNG_MAX_PALETTE_LENGTH */
999 num = (int)length / 3;
1000
1001 /* If the palette has 256 or fewer entries but is too large for the bit
1002 * depth, we don't issue an error, to preserve the behavior of previous
1003 * libpng versions. We silently truncate the unused extra palette entries
1004 * here.
1005 */
1006 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1007 max_palette_length = (1 << png_ptr->bit_depth);
1008 else
1009 max_palette_length = PNG_MAX_PALETTE_LENGTH;
1010
1011 if (num > max_palette_length)
1012 num = max_palette_length;
1013
1014 #ifdef PNG_POINTER_INDEXING_SUPPORTED
1015 for (i = 0, pal_ptr = palette; i < num; i++, pal_ptr++)
1016 {
1017 png_byte buf[3];
1018
1019 png_crc_read(png_ptr, buf, 3);
1020 pal_ptr->red = buf[0];
1021 pal_ptr->green = buf[1];
1022 pal_ptr->blue = buf[2];
1023 }
1024 #else
1025 for (i = 0; i < num; i++)
1026 {
1027 png_byte buf[3];
1028
1029 png_crc_read(png_ptr, buf, 3);
1030 /* Don't depend upon png_color being any order */
1031 palette[i].red = buf[0];
1032 palette[i].green = buf[1];
1033 palette[i].blue = buf[2];
1034 }
1035 #endif
1036
1037 /* If we actually need the PLTE chunk (ie for a paletted image), we do
1038 * whatever the normal CRC configuration tells us. However, if we
1039 * have an RGB image, the PLTE can be considered ancillary, so
1040 * we will act as though it is.
1041 */
1042 #ifndef PNG_READ_OPT_PLTE_SUPPORTED
1043 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1044 #endif
1045 {
1046 png_crc_finish(png_ptr, (png_uint_32) (length - (unsigned int)num * 3));
1047 }
1048
1049 #ifndef PNG_READ_OPT_PLTE_SUPPORTED
1050 else if (png_crc_error(png_ptr) != 0) /* Only if we have a CRC error */
1051 {
1052 /* If we don't want to use the data from an ancillary chunk,
1053 * we have two options: an error abort, or a warning and we
1054 * ignore the data in this chunk (which should be OK, since
1055 * it's considered ancillary for a RGB or RGBA image).
1056 *
1057 * IMPLEMENTATION NOTE: this is only here because png_crc_finish uses the
1058 * chunk type to determine whether to check the ancillary or the critical
1059 * flags.
1060 */
1061 if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_USE) == 0)
1062 {
1063 if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) != 0)
1064 return;
1065
1066 else
1067 png_chunk_error(png_ptr, "CRC error");
1068 }
1069
1070 /* Otherwise, we (optionally) emit a warning and use the chunk. */
1071 else if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) == 0)
1072 png_chunk_warning(png_ptr, "CRC error");
1073 }
1074 #endif
1075
1076 /* TODO: png_set_PLTE has the side effect of setting png_ptr->palette to its
1077 * own copy of the palette. This has the side effect that when png_start_row
1078 * is called (this happens after any call to png_read_update_info) the
1079 * info_ptr palette gets changed. This is extremely unexpected and
1080 * confusing.
1081 *
1082 * Fix this by not sharing the palette in this way.
1083 */
1084 png_set_PLTE(png_ptr, info_ptr, palette, num);
1085
1086 /* The three chunks, bKGD, hIST and tRNS *must* appear after PLTE and before
1087 * IDAT. Prior to 1.6.0 this was not checked; instead the code merely
1088 * checked the apparent validity of a tRNS chunk inserted before PLTE on a
1089 * palette PNG. 1.6.0 attempts to rigorously follow the standard and
1090 * therefore does a benign error if the erroneous condition is detected *and*
1091 * cancels the tRNS if the benign error returns. The alternative is to
1092 * amend the standard since it would be rather hypocritical of the standards
1093 * maintainers to ignore it.
1094 */
1095 #ifdef PNG_READ_tRNS_SUPPORTED
1096 if (png_ptr->num_trans > 0 ||
1097 (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS) != 0))
1098 {
1099 /* Cancel this because otherwise it would be used if the transforms
1100 * require it. Don't cancel the 'valid' flag because this would prevent
1101 * detection of duplicate chunks.
1102 */
1103 png_ptr->num_trans = 0;
1104
1105 if (info_ptr != NULL)
1106 info_ptr->num_trans = 0;
1107
1108 png_chunk_benign_error(png_ptr, "tRNS must be after");
1109 }
1110 #endif
1111
1112 #ifdef PNG_READ_hIST_SUPPORTED
1113 if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST) != 0)
1114 png_chunk_benign_error(png_ptr, "hIST must be after");
1115 #endif
1116
1117 #ifdef PNG_READ_bKGD_SUPPORTED
1118 if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD) != 0)
1119 png_chunk_benign_error(png_ptr, "bKGD must be after");
1120 #endif
1121 }
1122
1123 void /* PRIVATE */
1124 png_handle_IEND(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1125 {
1126 png_debug(1, "in png_handle_IEND");
1127
1128 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0 ||
1129 (png_ptr->mode & PNG_HAVE_IDAT) == 0)
1130 png_chunk_error(png_ptr, "out of place");
1131
1132 png_ptr->mode |= (PNG_AFTER_IDAT | PNG_HAVE_IEND);
1133
1134 png_crc_finish(png_ptr, length);
1135
1136 if (length != 0)
1137 png_chunk_benign_error(png_ptr, "invalid");
1138
1139 PNG_UNUSED(info_ptr)
1140 }
1141
1142 #ifdef PNG_READ_gAMA_SUPPORTED
1143 void /* PRIVATE */
1144 png_handle_gAMA(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1145 {
1146 png_fixed_point igamma;
1147 png_byte buf[4];
1148
1149 png_debug(1, "in png_handle_gAMA");
1150
1151 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1152 png_chunk_error(png_ptr, "missing IHDR");
1153
1154 else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
1155 {
1156 png_crc_finish(png_ptr, length);
1157 png_chunk_benign_error(png_ptr, "out of place");
1158 return;
1159 }
1160
1161 if (length != 4)
1162 {
1163 png_crc_finish(png_ptr, length);
1164 png_chunk_benign_error(png_ptr, "invalid");
1165 return;
1166 }
1167
1168 png_crc_read(png_ptr, buf, 4);
1169
1170 if (png_crc_finish(png_ptr, 0) != 0)
1171 return;
1172
1173 igamma = png_get_fixed_point(NULL, buf);
1174
1175 png_colorspace_set_gamma(png_ptr, &png_ptr->colorspace, igamma);
1176 png_colorspace_sync(png_ptr, info_ptr);
1177 }
1178 #endif
1179
1180 #ifdef PNG_READ_sBIT_SUPPORTED
1181 void /* PRIVATE */
1182 png_handle_sBIT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1183 {
1184 unsigned int truelen, i;
1185 png_byte sample_depth;
1186 png_byte buf[4];
1187
1188 png_debug(1, "in png_handle_sBIT");
1189
1190 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1191 png_chunk_error(png_ptr, "missing IHDR");
1192
1193 else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
1194 {
1195 png_crc_finish(png_ptr, length);
1196 png_chunk_benign_error(png_ptr, "out of place");
1197 return;
1198 }
1199
1200 if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sBIT) != 0)
1201 {
1202 png_crc_finish(png_ptr, length);
1203 png_chunk_benign_error(png_ptr, "duplicate");
1204 return;
1205 }
1206
1207 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1208 {
1209 truelen = 3;
1210 sample_depth = 8;
1211 }
1212
1213 else
1214 {
1215 truelen = png_ptr->channels;
1216 sample_depth = png_ptr->bit_depth;
1217 }
1218
1219 if (length != truelen || length > 4)
1220 {
1221 png_chunk_benign_error(png_ptr, "invalid");
1222 png_crc_finish(png_ptr, length);
1223 return;
1224 }
1225
1226 buf[0] = buf[1] = buf[2] = buf[3] = sample_depth;
1227 png_crc_read(png_ptr, buf, truelen);
1228
1229 if (png_crc_finish(png_ptr, 0) != 0)
1230 return;
1231
1232 for (i=0; i<truelen; ++i)
1233 {
1234 if (buf[i] == 0 || buf[i] > sample_depth)
1235 {
1236 png_chunk_benign_error(png_ptr, "invalid");
1237 return;
1238 }
1239 }
1240
1241 if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
1242 {
1243 png_ptr->sig_bit.red = buf[0];
1244 png_ptr->sig_bit.green = buf[1];
1245 png_ptr->sig_bit.blue = buf[2];
1246 png_ptr->sig_bit.alpha = buf[3];
1247 }
1248
1249 else
1250 {
1251 png_ptr->sig_bit.gray = buf[0];
1252 png_ptr->sig_bit.red = buf[0];
1253 png_ptr->sig_bit.green = buf[0];
1254 png_ptr->sig_bit.blue = buf[0];
1255 png_ptr->sig_bit.alpha = buf[1];
1256 }
1257
1258 png_set_sBIT(png_ptr, info_ptr, &(png_ptr->sig_bit));
1259 }
1260 #endif
1261
1262 #ifdef PNG_READ_cHRM_SUPPORTED
1263 void /* PRIVATE */
1264 png_handle_cHRM(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1265 {
1266 png_byte buf[32];
1267 png_xy xy;
1268
1269 png_debug(1, "in png_handle_cHRM");
1270
1271 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1272 png_chunk_error(png_ptr, "missing IHDR");
1273
1274 else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
1275 {
1276 png_crc_finish(png_ptr, length);
1277 png_chunk_benign_error(png_ptr, "out of place");
1278 return;
1279 }
1280
1281 if (length != 32)
1282 {
1283 png_crc_finish(png_ptr, length);
1284 png_chunk_benign_error(png_ptr, "invalid");
1285 return;
1286 }
1287
1288 png_crc_read(png_ptr, buf, 32);
1289
1290 if (png_crc_finish(png_ptr, 0) != 0)
1291 return;
1292
1293 xy.whitex = png_get_fixed_point(NULL, buf);
1294 xy.whitey = png_get_fixed_point(NULL, buf + 4);
1295 xy.redx = png_get_fixed_point(NULL, buf + 8);
1296 xy.redy = png_get_fixed_point(NULL, buf + 12);
1297 xy.greenx = png_get_fixed_point(NULL, buf + 16);
1298 xy.greeny = png_get_fixed_point(NULL, buf + 20);
1299 xy.bluex = png_get_fixed_point(NULL, buf + 24);
1300 xy.bluey = png_get_fixed_point(NULL, buf + 28);
1301
1302 if (xy.whitex == PNG_FIXED_ERROR ||
1303 xy.whitey == PNG_FIXED_ERROR ||
1304 xy.redx == PNG_FIXED_ERROR ||
1305 xy.redy == PNG_FIXED_ERROR ||
1306 xy.greenx == PNG_FIXED_ERROR ||
1307 xy.greeny == PNG_FIXED_ERROR ||
1308 xy.bluex == PNG_FIXED_ERROR ||
1309 xy.bluey == PNG_FIXED_ERROR)
1310 {
1311 png_chunk_benign_error(png_ptr, "invalid values");
1312 return;
1313 }
1314
1315 /* If a colorspace error has already been output skip this chunk */
1316 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0)
1317 return;
1318
1319 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_FROM_cHRM) != 0)
1320 {
1321 png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID;
1322 png_colorspace_sync(png_ptr, info_ptr);
1323 png_chunk_benign_error(png_ptr, "duplicate");
1324 return;
1325 }
1326
1327 png_ptr->colorspace.flags |= PNG_COLORSPACE_FROM_cHRM;
1328 (void)png_colorspace_set_chromaticities(png_ptr, &png_ptr->colorspace, &xy,
1329 1/*prefer cHRM values*/);
1330 png_colorspace_sync(png_ptr, info_ptr);
1331 }
1332 #endif
1333
1334 #ifdef PNG_READ_sRGB_SUPPORTED
1335 void /* PRIVATE */
1336 png_handle_sRGB(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1337 {
1338 png_byte intent;
1339
1340 png_debug(1, "in png_handle_sRGB");
1341
1342 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1343 png_chunk_error(png_ptr, "missing IHDR");
1344
1345 else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
1346 {
1347 png_crc_finish(png_ptr, length);
1348 png_chunk_benign_error(png_ptr, "out of place");
1349 return;
1350 }
1351
1352 if (length != 1)
1353 {
1354 png_crc_finish(png_ptr, length);
1355 png_chunk_benign_error(png_ptr, "invalid");
1356 return;
1357 }
1358
1359 png_crc_read(png_ptr, &intent, 1);
1360
1361 if (png_crc_finish(png_ptr, 0) != 0)
1362 return;
1363
1364 /* If a colorspace error has already been output skip this chunk */
1365 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0)
1366 return;
1367
1368 /* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect
1369 * this.
1370 */
1371 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_INTENT) != 0)
1372 {
1373 png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID;
1374 png_colorspace_sync(png_ptr, info_ptr);
1375 png_chunk_benign_error(png_ptr, "too many profiles");
1376 return;
1377 }
1378
1379 (void)png_colorspace_set_sRGB(png_ptr, &png_ptr->colorspace, intent);
1380 png_colorspace_sync(png_ptr, info_ptr);
1381 }
1382 #endif /* READ_sRGB */
1383
1384 #ifdef PNG_READ_iCCP_SUPPORTED
1385 void /* PRIVATE */
1386 png_handle_iCCP(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1387 /* Note: this does not properly handle profiles that are > 64K under DOS */
1388 {
1389 png_const_charp errmsg = NULL; /* error message output, or no error */
1390 int finished = 0; /* crc checked */
1391
1392 png_debug(1, "in png_handle_iCCP");
1393
1394 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1395 png_chunk_error(png_ptr, "missing IHDR");
1396
1397 else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
1398 {
1399 png_crc_finish(png_ptr, length);
1400 png_chunk_benign_error(png_ptr, "out of place");
1401 return;
1402 }
1403
1404 /* Consistent with all the above colorspace handling an obviously *invalid*
1405 * chunk is just ignored, so does not invalidate the color space. An
1406 * alternative is to set the 'invalid' flags at the start of this routine
1407 * and only clear them in they were not set before and all the tests pass.
1408 * The minimum 'deflate' stream is assumed to be just the 2 byte header and
1409 * 4 byte checksum. The keyword must be at least one character and there is
1410 * a terminator (0) byte and the compression method.
1411 */
1412 if (length < 9)
1413 {
1414 png_crc_finish(png_ptr, length);
1415 png_chunk_benign_error(png_ptr, "too short");
1416 return;
1417 }
1418
1419 /* If a colorspace error has already been output skip this chunk */
1420 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0)
1421 {
1422 png_crc_finish(png_ptr, length);
1423 return;
1424 }
1425
1426 /* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect
1427 * this.
1428 */
1429 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_INTENT) == 0)
1430 {
1431 uInt read_length, keyword_length;
1432 char keyword[81];
1433
1434 /* Find the keyword; the keyword plus separator and compression method
1435 * bytes can be at most 81 characters long.
1436 */
1437 read_length = 81; /* maximum */
1438 if (read_length > length)
1439 read_length = (uInt)length;
1440
1441 png_crc_read(png_ptr, (png_bytep)keyword, read_length);
1442 length -= read_length;
1443
1444 keyword_length = 0;
1445 while (keyword_length < 80 && keyword_length < read_length &&
1446 keyword[keyword_length] != 0)
1447 ++keyword_length;
1448
1449 /* TODO: make the keyword checking common */
1450 if (keyword_length >= 1 && keyword_length <= 79)
1451 {
1452 /* We only understand '0' compression - deflate - so if we get a
1453 * different value we can't safely decode the chunk.
1454 */
1455 if (keyword_length+1 < read_length &&
1456 keyword[keyword_length+1] == PNG_COMPRESSION_TYPE_BASE)
1457 {
1458 read_length -= keyword_length+2;
1459
1460 if (png_inflate_claim(png_ptr, png_iCCP) == Z_OK)
1461 {
1462 Byte profile_header[132];
1463 Byte local_buffer[PNG_INFLATE_BUF_SIZE];
1464 png_alloc_size_t size = (sizeof profile_header);
1465
1466 png_ptr->zstream.next_in = (Bytef*)keyword + (keyword_length+2);
1467 png_ptr->zstream.avail_in = read_length;
1468 (void)png_inflate_read(png_ptr, local_buffer,
1469 (sizeof local_buffer), &length, profile_header, &size,
1470 0/*finish: don't, because the output is too small*/);
1471
1472 if (size == 0)
1473 {
1474 /* We have the ICC profile header; do the basic header checks.
1475 */
1476 const png_uint_32 profile_length =
1477 png_get_uint_32(profile_header);
1478
1479 if (png_icc_check_length(png_ptr, &png_ptr->colorspace,
1480 keyword, profile_length) != 0)
1481 {
1482 /* The length is apparently ok, so we can check the 132
1483 * byte header.
1484 */
1485 if (png_icc_check_header(png_ptr, &png_ptr->colorspace,
1486 keyword, profile_length, profile_header,
1487 png_ptr->color_type) != 0)
1488 {
1489 /* Now read the tag table; a variable size buffer is
1490 * needed at this point, allocate one for the whole
1491 * profile. The header check has already validated
1492 * that none of these stuff will overflow.
1493 */
1494 const png_uint_32 tag_count = png_get_uint_32(
1495 profile_header+128);
1496 png_bytep profile = png_read_buffer(png_ptr,
1497 profile_length, 2/*silent*/);
1498
1499 if (profile != NULL)
1500 {
1501 memcpy(profile, profile_header,
1502 (sizeof profile_header));
1503
1504 size = 12 * tag_count;
1505
1506 (void)png_inflate_read(png_ptr, local_buffer,
1507 (sizeof local_buffer), &length,
1508 profile + (sizeof profile_header), &size, 0);
1509
1510 /* Still expect a buffer error because we expect
1511 * there to be some tag data!
1512 */
1513 if (size == 0)
1514 {
1515 if (png_icc_check_tag_table(png_ptr,
1516 &png_ptr->colorspace, keyword, profile_length,
1517 profile) != 0)
1518 {
1519 /* The profile has been validated for basic
1520 * security issues, so read the whole thing in.
1521 */
1522 size = profile_length - (sizeof profile_header)
1523 - 12 * tag_count;
1524
1525 (void)png_inflate_read(png_ptr, local_buffer,
1526 (sizeof local_buffer), &length,
1527 profile + (sizeof profile_header) +
1528 12 * tag_count, &size, 1/*finish*/);
1529
1530 if (length > 0 && !(png_ptr->flags &
1531 PNG_FLAG_BENIGN_ERRORS_WARN))
1532 errmsg = "extra compressed data";
1533
1534 /* But otherwise allow extra data: */
1535 else if (size == 0)
1536 {
1537 if (length > 0)
1538 {
1539 /* This can be handled completely, so
1540 * keep going.
1541 */
1542 png_chunk_warning(png_ptr,
1543 "extra compressed data");
1544 }
1545
1546 png_crc_finish(png_ptr, length);
1547 finished = 1;
1548
1549 # if defined(PNG_sRGB_SUPPORTED) && PNG_sRGB_PROFILE_CHECKS >= 0
1550 /* Check for a match against sRGB */
1551 png_icc_set_sRGB(png_ptr,
1552 &png_ptr->colorspace, profile,
1553 png_ptr->zstream.adler);
1554 # endif
1555
1556 /* Steal the profile for info_ptr. */
1557 if (info_ptr != NULL)
1558 {
1559 png_free_data(png_ptr, info_ptr,
1560 PNG_FREE_ICCP, 0);
1561
1562 info_ptr->iccp_name = png_voidcast(char*,
1563 png_malloc_base(png_ptr,
1564 keyword_length+1));
1565 if (info_ptr->iccp_name != NULL)
1566 {
1567 memcpy(info_ptr->iccp_name, keyword,
1568 keyword_length+1);
1569 info_ptr->iccp_proflen =
1570 profile_length;
1571 info_ptr->iccp_profile = profile;
1572 png_ptr->read_buffer = NULL; /*steal*/
1573 info_ptr->free_me |= PNG_FREE_ICCP;
1574 info_ptr->valid |= PNG_INFO_iCCP;
1575 }
1576
1577 else
1578 {
1579 png_ptr->colorspace.flags |=
1580 PNG_COLORSPACE_INVALID;
1581 errmsg = "out of memory";
1582 }
1583 }
1584
1585 /* else the profile remains in the read
1586 * buffer which gets reused for subsequent
1587 * chunks.
1588 */
1589
1590 if (info_ptr != NULL)
1591 png_colorspace_sync(png_ptr, info_ptr);
1592
1593 if (errmsg == NULL)
1594 {
1595 png_ptr->zowner = 0;
1596 return;
1597 }
1598 }
1599
1600 else if (size > 0)
1601 errmsg = "truncated";
1602
1603 #ifndef __COVERITY__
1604 else
1605 errmsg = png_ptr->zstream.msg;
1606 #endif
1607 }
1608
1609 /* else png_icc_check_tag_table output an error */
1610 }
1611
1612 else /* profile truncated */
1613 errmsg = png_ptr->zstream.msg;
1614 }
1615
1616 else
1617 errmsg = "out of memory";
1618 }
1619
1620 /* else png_icc_check_header output an error */
1621 }
1622
1623 /* else png_icc_check_length output an error */
1624 }
1625
1626 else /* profile truncated */
1627 errmsg = png_ptr->zstream.msg;
1628
1629 /* Release the stream */
1630 png_ptr->zowner = 0;
1631 }
1632
1633 else /* png_inflate_claim failed */
1634 errmsg = png_ptr->zstream.msg;
1635 }
1636
1637 else
1638 errmsg = "bad compression method"; /* or missing */
1639 }
1640
1641 else
1642 errmsg = "bad keyword";
1643 }
1644
1645 else
1646 errmsg = "too many profiles";
1647
1648 /* Failure: the reason is in 'errmsg' */
1649 if (finished == 0)
1650 png_crc_finish(png_ptr, length);
1651
1652 png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID;
1653 png_colorspace_sync(png_ptr, info_ptr);
1654 if (errmsg != NULL) /* else already output */
1655 png_chunk_benign_error(png_ptr, errmsg);
1656 }
1657 #endif /* READ_iCCP */
1658
1659 #ifdef PNG_READ_sPLT_SUPPORTED
1660 void /* PRIVATE */
1661 png_handle_sPLT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1662 /* Note: this does not properly handle chunks that are > 64K under DOS */
1663 {
1664 png_bytep entry_start, buffer;
1665 png_sPLT_t new_palette;
1666 png_sPLT_entryp pp;
1667 png_uint_32 data_length;
1668 int entry_size, i;
1669 png_uint_32 skip = 0;
1670 png_uint_32 dl;
1671 png_size_t max_dl;
1672
1673 png_debug(1, "in png_handle_sPLT");
1674
1675 #ifdef PNG_USER_LIMITS_SUPPORTED
1676 if (png_ptr->user_chunk_cache_max != 0)
1677 {
1678 if (png_ptr->user_chunk_cache_max == 1)
1679 {
1680 png_crc_finish(png_ptr, length);
1681 return;
1682 }
1683
1684 if (--png_ptr->user_chunk_cache_max == 1)
1685 {
1686 png_warning(png_ptr, "No space in chunk cache for sPLT");
1687 png_crc_finish(png_ptr, length);
1688 return;
1689 }
1690 }
1691 #endif
1692
1693 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1694 png_chunk_error(png_ptr, "missing IHDR");
1695
1696 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
1697 {
1698 png_crc_finish(png_ptr, length);
1699 png_chunk_benign_error(png_ptr, "out of place");
1700 return;
1701 }
1702
1703 #ifdef PNG_MAX_MALLOC_64K
1704 if (length > 65535U)
1705 {
1706 png_crc_finish(png_ptr, length);
1707 png_chunk_benign_error(png_ptr, "too large to fit in memory");
1708 return;
1709 }
1710 #endif
1711
1712 buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/);
1713 if (buffer == NULL)
1714 {
1715 png_crc_finish(png_ptr, length);
1716 png_chunk_benign_error(png_ptr, "out of memory");
1717 return;
1718 }
1719
1720
1721 /* WARNING: this may break if size_t is less than 32 bits; it is assumed
1722 * that the PNG_MAX_MALLOC_64K test is enabled in this case, but this is a
1723 * potential breakage point if the types in pngconf.h aren't exactly right.
1724 */
1725 png_crc_read(png_ptr, buffer, length);
1726
1727 if (png_crc_finish(png_ptr, skip) != 0)
1728 return;
1729
1730 buffer[length] = 0;
1731
1732 for (entry_start = buffer; *entry_start; entry_start++)
1733 /* Empty loop to find end of name */ ;
1734
1735 ++entry_start;
1736
1737 /* A sample depth should follow the separator, and we should be on it */
1738 if (length < 2U || entry_start > buffer + (length - 2U))
1739 {
1740 png_warning(png_ptr, "malformed sPLT chunk");
1741 return;
1742 }
1743
1744 new_palette.depth = *entry_start++;
1745 entry_size = (new_palette.depth == 8 ? 6 : 10);
1746 /* This must fit in a png_uint_32 because it is derived from the original
1747 * chunk data length.
1748 */
1749 data_length = length - (png_uint_32)(entry_start - buffer);
1750
1751 /* Integrity-check the data length */
1752 if ((data_length % (unsigned int)entry_size) != 0)
1753 {
1754 png_warning(png_ptr, "sPLT chunk has bad length");
1755 return;
1756 }
1757
1758 dl = (png_uint_32)(data_length / (unsigned int)entry_size);
1759 max_dl = PNG_SIZE_MAX / (sizeof (png_sPLT_entry));
1760
1761 if (dl > max_dl)
1762 {
1763 png_warning(png_ptr, "sPLT chunk too long");
1764 return;
1765 }
1766
1767 new_palette.nentries = (png_int_32)(data_length / (unsigned int)entry_size);
1768
1769 new_palette.entries = (png_sPLT_entryp)png_malloc_warn(png_ptr,
1770 (png_alloc_size_t) new_palette.nentries * (sizeof (png_sPLT_entry)));
1771
1772 if (new_palette.entries == NULL)
1773 {
1774 png_warning(png_ptr, "sPLT chunk requires too much memory");
1775 return;
1776 }
1777
1778 #ifdef PNG_POINTER_INDEXING_SUPPORTED
1779 for (i = 0; i < new_palette.nentries; i++)
1780 {
1781 pp = new_palette.entries + i;
1782
1783 if (new_palette.depth == 8)
1784 {
1785 pp->red = *entry_start++;
1786 pp->green = *entry_start++;
1787 pp->blue = *entry_start++;
1788 pp->alpha = *entry_start++;
1789 }
1790
1791 else
1792 {
1793 pp->red = png_get_uint_16(entry_start); entry_start += 2;
1794 pp->green = png_get_uint_16(entry_start); entry_start += 2;
1795 pp->blue = png_get_uint_16(entry_start); entry_start += 2;
1796 pp->alpha = png_get_uint_16(entry_start); entry_start += 2;
1797 }
1798
1799 pp->frequency = png_get_uint_16(entry_start); entry_start += 2;
1800 }
1801 #else
1802 pp = new_palette.entries;
1803
1804 for (i = 0; i < new_palette.nentries; i++)
1805 {
1806
1807 if (new_palette.depth == 8)
1808 {
1809 pp[i].red = *entry_start++;
1810 pp[i].green = *entry_start++;
1811 pp[i].blue = *entry_start++;
1812 pp[i].alpha = *entry_start++;
1813 }
1814
1815 else
1816 {
1817 pp[i].red = png_get_uint_16(entry_start); entry_start += 2;
1818 pp[i].green = png_get_uint_16(entry_start); entry_start += 2;
1819 pp[i].blue = png_get_uint_16(entry_start); entry_start += 2;
1820 pp[i].alpha = png_get_uint_16(entry_start); entry_start += 2;
1821 }
1822
1823 pp[i].frequency = png_get_uint_16(entry_start); entry_start += 2;
1824 }
1825 #endif
1826
1827 /* Discard all chunk data except the name and stash that */
1828 new_palette.name = (png_charp)buffer;
1829
1830 png_set_sPLT(png_ptr, info_ptr, &new_palette, 1);
1831
1832 png_free(png_ptr, new_palette.entries);
1833 }
1834 #endif /* READ_sPLT */
1835
1836 #ifdef PNG_READ_tRNS_SUPPORTED
1837 void /* PRIVATE */
1838 png_handle_tRNS(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1839 {
1840 png_byte readbuf[PNG_MAX_PALETTE_LENGTH];
1841
1842 png_debug(1, "in png_handle_tRNS");
1843
1844 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1845 png_chunk_error(png_ptr, "missing IHDR");
1846
1847 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
1848 {
1849 png_crc_finish(png_ptr, length);
1850 png_chunk_benign_error(png_ptr, "out of place");
1851 return;
1852 }
1853
1854 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS) != 0)
1855 {
1856 png_crc_finish(png_ptr, length);
1857 png_chunk_benign_error(png_ptr, "duplicate");
1858 return;
1859 }
1860
1861 if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
1862 {
1863 png_byte buf[2];
1864
1865 if (length != 2)
1866 {
1867 png_crc_finish(png_ptr, length);
1868 png_chunk_benign_error(png_ptr, "invalid");
1869 return;
1870 }
1871
1872 png_crc_read(png_ptr, buf, 2);
1873 png_ptr->num_trans = 1;
1874 png_ptr->trans_color.gray = png_get_uint_16(buf);
1875 }
1876
1877 else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
1878 {
1879 png_byte buf[6];
1880
1881 if (length != 6)
1882 {
1883 png_crc_finish(png_ptr, length);
1884 png_chunk_benign_error(png_ptr, "invalid");
1885 return;
1886 }
1887
1888 png_crc_read(png_ptr, buf, length);
1889 png_ptr->num_trans = 1;
1890 png_ptr->trans_color.red = png_get_uint_16(buf);
1891 png_ptr->trans_color.green = png_get_uint_16(buf + 2);
1892 png_ptr->trans_color.blue = png_get_uint_16(buf + 4);
1893 }
1894
1895 else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1896 {
1897 if ((png_ptr->mode & PNG_HAVE_PLTE) == 0)
1898 {
1899 /* TODO: is this actually an error in the ISO spec? */
1900 png_crc_finish(png_ptr, length);
1901 png_chunk_benign_error(png_ptr, "out of place");
1902 return;
1903 }
1904
1905 if (length > (unsigned int) png_ptr->num_palette ||
1906 length > (unsigned int) PNG_MAX_PALETTE_LENGTH ||
1907 length == 0)
1908 {
1909 png_crc_finish(png_ptr, length);
1910 png_chunk_benign_error(png_ptr, "invalid");
1911 return;
1912 }
1913
1914 png_crc_read(png_ptr, readbuf, length);
1915 png_ptr->num_trans = (png_uint_16)length;
1916 }
1917
1918 else
1919 {
1920 png_crc_finish(png_ptr, length);
1921 png_chunk_benign_error(png_ptr, "invalid with alpha channel");
1922 return;
1923 }
1924
1925 if (png_crc_finish(png_ptr, 0) != 0)
1926 {
1927 png_ptr->num_trans = 0;
1928 return;
1929 }
1930
1931 /* TODO: this is a horrible side effect in the palette case because the
1932 * png_struct ends up with a pointer to the tRNS buffer owned by the
1933 * png_info. Fix this.
1934 */
1935 png_set_tRNS(png_ptr, info_ptr, readbuf, png_ptr->num_trans,
1936 &(png_ptr->trans_color));
1937 }
1938 #endif
1939
1940 #ifdef PNG_READ_bKGD_SUPPORTED
1941 void /* PRIVATE */
1942 png_handle_bKGD(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1943 {
1944 unsigned int truelen;
1945 png_byte buf[6];
1946 png_color_16 background;
1947
1948 png_debug(1, "in png_handle_bKGD");
1949
1950 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1951 png_chunk_error(png_ptr, "missing IHDR");
1952
1953 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0 ||
1954 (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
1955 (png_ptr->mode & PNG_HAVE_PLTE) == 0))
1956 {
1957 png_crc_finish(png_ptr, length);
1958 png_chunk_benign_error(png_ptr, "out of place");
1959 return;
1960 }
1961
1962 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD) != 0)
1963 {
1964 png_crc_finish(png_ptr, length);
1965 png_chunk_benign_error(png_ptr, "duplicate");
1966 return;
1967 }
1968
1969 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1970 truelen = 1;
1971
1972 else if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
1973 truelen = 6;
1974
1975 else
1976 truelen = 2;
1977
1978 if (length != truelen)
1979 {
1980 png_crc_finish(png_ptr, length);
1981 png_chunk_benign_error(png_ptr, "invalid");
1982 return;
1983 }
1984
1985 png_crc_read(png_ptr, buf, truelen);
1986
1987 if (png_crc_finish(png_ptr, 0) != 0)
1988 return;
1989
1990 /* We convert the index value into RGB components so that we can allow
1991 * arbitrary RGB values for background when we have transparency, and
1992 * so it is easy to determine the RGB values of the background color
1993 * from the info_ptr struct.
1994 */
1995 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1996 {
1997 background.index = buf[0];
1998
1999 if (info_ptr != NULL && info_ptr->num_palette != 0)
2000 {
2001 if (buf[0] >= info_ptr->num_palette)
2002 {
2003 png_chunk_benign_error(png_ptr, "invalid index");
2004 return;
2005 }
2006
2007 background.red = (png_uint_16)png_ptr->palette[buf[0]].red;
2008 background.green = (png_uint_16)png_ptr->palette[buf[0]].green;
2009 background.blue = (png_uint_16)png_ptr->palette[buf[0]].blue;
2010 }
2011
2012 else
2013 background.red = background.green = background.blue = 0;
2014
2015 background.gray = 0;
2016 }
2017
2018 else if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0) /* GRAY */
2019 {
2020 background.index = 0;
2021 background.red =
2022 background.green =
2023 background.blue =
2024 background.gray = png_get_uint_16(buf);
2025 }
2026
2027 else
2028 {
2029 background.index = 0;
2030 background.red = png_get_uint_16(buf);
2031 background.green = png_get_uint_16(buf + 2);
2032 background.blue = png_get_uint_16(buf + 4);
2033 background.gray = 0;
2034 }
2035
2036 png_set_bKGD(png_ptr, info_ptr, &background);
2037 }
2038 #endif
2039
2040 #ifdef PNG_READ_hIST_SUPPORTED
2041 void /* PRIVATE */
2042 png_handle_hIST(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2043 {
2044 unsigned int num, i;
2045 png_uint_16 readbuf[PNG_MAX_PALETTE_LENGTH];
2046
2047 png_debug(1, "in png_handle_hIST");
2048
2049 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2050 png_chunk_error(png_ptr, "missing IHDR");
2051
2052 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0 ||
2053 (png_ptr->mode & PNG_HAVE_PLTE) == 0)
2054 {
2055 png_crc_finish(png_ptr, length);
2056 png_chunk_benign_error(png_ptr, "out of place");
2057 return;
2058 }
2059
2060 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST) != 0)
2061 {
2062 png_crc_finish(png_ptr, length);
2063 png_chunk_benign_error(png_ptr, "duplicate");
2064 return;
2065 }
2066
2067 num = length / 2 ;
2068
2069 if (num != (unsigned int) png_ptr->num_palette ||
2070 num > (unsigned int) PNG_MAX_PALETTE_LENGTH)
2071 {
2072 png_crc_finish(png_ptr, length);
2073 png_chunk_benign_error(png_ptr, "invalid");
2074 return;
2075 }
2076
2077 for (i = 0; i < num; i++)
2078 {
2079 png_byte buf[2];
2080
2081 png_crc_read(png_ptr, buf, 2);
2082 readbuf[i] = png_get_uint_16(buf);
2083 }
2084
2085 if (png_crc_finish(png_ptr, 0) != 0)
2086 return;
2087
2088 png_set_hIST(png_ptr, info_ptr, readbuf);
2089 }
2090 #endif
2091
2092 #ifdef PNG_READ_pHYs_SUPPORTED
2093 void /* PRIVATE */
2094 png_handle_pHYs(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2095 {
2096 png_byte buf[9];
2097 png_uint_32 res_x, res_y;
2098 int unit_type;
2099
2100 png_debug(1, "in png_handle_pHYs");
2101
2102 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2103 png_chunk_error(png_ptr, "missing IHDR");
2104
2105 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2106 {
2107 png_crc_finish(png_ptr, length);
2108 png_chunk_benign_error(png_ptr, "out of place");
2109 return;
2110 }
2111
2112 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs) != 0)
2113 {
2114 png_crc_finish(png_ptr, length);
2115 png_chunk_benign_error(png_ptr, "duplicate");
2116 return;
2117 }
2118
2119 if (length != 9)
2120 {
2121 png_crc_finish(png_ptr, length);
2122 png_chunk_benign_error(png_ptr, "invalid");
2123 return;
2124 }
2125
2126 png_crc_read(png_ptr, buf, 9);
2127
2128 if (png_crc_finish(png_ptr, 0) != 0)
2129 return;
2130
2131 res_x = png_get_uint_32(buf);
2132 res_y = png_get_uint_32(buf + 4);
2133 unit_type = buf[8];
2134 png_set_pHYs(png_ptr, info_ptr, res_x, res_y, unit_type);
2135 }
2136 #endif
2137
2138 #ifdef PNG_READ_oFFs_SUPPORTED
2139 void /* PRIVATE */
2140 png_handle_oFFs(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2141 {
2142 png_byte buf[9];
2143 png_int_32 offset_x, offset_y;
2144 int unit_type;
2145
2146 png_debug(1, "in png_handle_oFFs");
2147
2148 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2149 png_chunk_error(png_ptr, "missing IHDR");
2150
2151 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2152 {
2153 png_crc_finish(png_ptr, length);
2154 png_chunk_benign_error(png_ptr, "out of place");
2155 return;
2156 }
2157
2158 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs) != 0)
2159 {
2160 png_crc_finish(png_ptr, length);
2161 png_chunk_benign_error(png_ptr, "duplicate");
2162 return;
2163 }
2164
2165 if (length != 9)
2166 {
2167 png_crc_finish(png_ptr, length);
2168 png_chunk_benign_error(png_ptr, "invalid");
2169 return;
2170 }
2171
2172 png_crc_read(png_ptr, buf, 9);
2173
2174 if (png_crc_finish(png_ptr, 0) != 0)
2175 return;
2176
2177 offset_x = png_get_int_32(buf);
2178 offset_y = png_get_int_32(buf + 4);
2179 unit_type = buf[8];
2180 png_set_oFFs(png_ptr, info_ptr, offset_x, offset_y, unit_type);
2181 }
2182 #endif
2183
2184 #ifdef PNG_READ_pCAL_SUPPORTED
2185 /* Read the pCAL chunk (described in the PNG Extensions document) */
2186 void /* PRIVATE */
2187 png_handle_pCAL(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2188 {
2189 png_int_32 X0, X1;
2190 png_byte type, nparams;
2191 png_bytep buffer, buf, units, endptr;
2192 png_charpp params;
2193 int i;
2194
2195 png_debug(1, "in png_handle_pCAL");
2196
2197 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2198 png_chunk_error(png_ptr, "missing IHDR");
2199
2200 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2201 {
2202 png_crc_finish(png_ptr, length);
2203 png_chunk_benign_error(png_ptr, "out of place");
2204 return;
2205 }
2206
2207 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pCAL) != 0)
2208 {
2209 png_crc_finish(png_ptr, length);
2210 png_chunk_benign_error(png_ptr, "duplicate");
2211 return;
2212 }
2213
2214 png_debug1(2, "Allocating and reading pCAL chunk data (%u bytes)",
2215 length + 1);
2216
2217 buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/);
2218
2219 if (buffer == NULL)
2220 {
2221 png_crc_finish(png_ptr, length);
2222 png_chunk_benign_error(png_ptr, "out of memory");
2223 return;
2224 }
2225
2226 png_crc_read(png_ptr, buffer, length);
2227
2228 if (png_crc_finish(png_ptr, 0) != 0)
2229 return;
2230
2231 buffer[length] = 0; /* Null terminate the last string */
2232
2233 png_debug(3, "Finding end of pCAL purpose string");
2234 for (buf = buffer; *buf; buf++)
2235 /* Empty loop */ ;
2236
2237 endptr = buffer + length;
2238
2239 /* We need to have at least 12 bytes after the purpose string
2240 * in order to get the parameter information.
2241 */
2242 if (endptr - buf <= 12)
2243 {
2244 png_chunk_benign_error(png_ptr, "invalid");
2245 return;
2246 }
2247
2248 png_debug(3, "Reading pCAL X0, X1, type, nparams, and units");
2249 X0 = png_get_int_32((png_bytep)buf+1);
2250 X1 = png_get_int_32((png_bytep)buf+5);
2251 type = buf[9];
2252 nparams = buf[10];
2253 units = buf + 11;
2254
2255 png_debug(3, "Checking pCAL equation type and number of parameters");
2256 /* Check that we have the right number of parameters for known
2257 * equation types.
2258 */
2259 if ((type == PNG_EQUATION_LINEAR && nparams != 2) ||
2260 (type == PNG_EQUATION_BASE_E && nparams != 3) ||
2261 (type == PNG_EQUATION_ARBITRARY && nparams != 3) ||
2262 (type == PNG_EQUATION_HYPERBOLIC && nparams != 4))
2263 {
2264 png_chunk_benign_error(png_ptr, "invalid parameter count");
2265 return;
2266 }
2267
2268 else if (type >= PNG_EQUATION_LAST)
2269 {
2270 png_chunk_benign_error(png_ptr, "unrecognized equation type");
2271 }
2272
2273 for (buf = units; *buf; buf++)
2274 /* Empty loop to move past the units string. */ ;
2275
2276 png_debug(3, "Allocating pCAL parameters array");
2277
2278 params = png_voidcast(png_charpp, png_malloc_warn(png_ptr,
2279 nparams * (sizeof (png_charp))));
2280
2281 if (params == NULL)
2282 {
2283 png_chunk_benign_error(png_ptr, "out of memory");
2284 return;
2285 }
2286
2287 /* Get pointers to the start of each parameter string. */
2288 for (i = 0; i < nparams; i++)
2289 {
2290 buf++; /* Skip the null string terminator from previous parameter. */
2291
2292 png_debug1(3, "Reading pCAL parameter %d", i);
2293
2294 for (params[i] = (png_charp)buf; buf <= endptr && *buf != 0; buf++)
2295 /* Empty loop to move past each parameter string */ ;
2296
2297 /* Make sure we haven't run out of data yet */
2298 if (buf > endptr)
2299 {
2300 png_free(png_ptr, params);
2301 png_chunk_benign_error(png_ptr, "invalid data");
2302 return;
2303 }
2304 }
2305
2306 png_set_pCAL(png_ptr, info_ptr, (png_charp)buffer, X0, X1, type, nparams,
2307 (png_charp)units, params);
2308
2309 png_free(png_ptr, params);
2310 }
2311 #endif
2312
2313 #ifdef PNG_READ_sCAL_SUPPORTED
2314 /* Read the sCAL chunk */
2315 void /* PRIVATE */
2316 png_handle_sCAL(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2317 {
2318 png_bytep buffer;
2319 png_size_t i;
2320 int state;
2321
2322 png_debug(1, "in png_handle_sCAL");
2323
2324 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2325 png_chunk_error(png_ptr, "missing IHDR");
2326
2327 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2328 {
2329 png_crc_finish(png_ptr, length);
2330 png_chunk_benign_error(png_ptr, "out of place");
2331 return;
2332 }
2333
2334 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sCAL) != 0)
2335 {
2336 png_crc_finish(png_ptr, length);
2337 png_chunk_benign_error(png_ptr, "duplicate");
2338 return;
2339 }
2340
2341 /* Need unit type, width, \0, height: minimum 4 bytes */
2342 else if (length < 4)
2343 {
2344 png_crc_finish(png_ptr, length);
2345 png_chunk_benign_error(png_ptr, "invalid");
2346 return;
2347 }
2348
2349 png_debug1(2, "Allocating and reading sCAL chunk data (%u bytes)",
2350 length + 1);
2351
2352 buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/);
2353
2354 if (buffer == NULL)
2355 {
2356 png_chunk_benign_error(png_ptr, "out of memory");
2357 png_crc_finish(png_ptr, length);
2358 return;
2359 }
2360
2361 png_crc_read(png_ptr, buffer, length);
2362 buffer[length] = 0; /* Null terminate the last string */
2363
2364 if (png_crc_finish(png_ptr, 0) != 0)
2365 return;
2366
2367 /* Validate the unit. */
2368 if (buffer[0] != 1 && buffer[0] != 2)
2369 {
2370 png_chunk_benign_error(png_ptr, "invalid unit");
2371 return;
2372 }
2373
2374 /* Validate the ASCII numbers, need two ASCII numbers separated by
2375 * a '\0' and they need to fit exactly in the chunk data.
2376 */
2377 i = 1;
2378 state = 0;
2379
2380 if (png_check_fp_number((png_const_charp)buffer, length, &state, &i) == 0 ||
2381 i >= length || buffer[i++] != 0)
2382 png_chunk_benign_error(png_ptr, "bad width format");
2383
2384 else if (PNG_FP_IS_POSITIVE(state) == 0)
2385 png_chunk_benign_error(png_ptr, "non-positive width");
2386
2387 else
2388 {
2389 png_size_t heighti = i;
2390
2391 state = 0;
2392 if (png_check_fp_number((png_const_charp)buffer, length,
2393 &state, &i) == 0 || i != length)
2394 png_chunk_benign_error(png_ptr, "bad height format");
2395
2396 else if (PNG_FP_IS_POSITIVE(state) == 0)
2397 png_chunk_benign_error(png_ptr, "non-positive height");
2398
2399 else
2400 /* This is the (only) success case. */
2401 png_set_sCAL_s(png_ptr, info_ptr, buffer[0],
2402 (png_charp)buffer+1, (png_charp)buffer+heighti);
2403 }
2404 }
2405 #endif
2406
2407 #ifdef PNG_READ_tIME_SUPPORTED
2408 void /* PRIVATE */
2409 png_handle_tIME(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2410 {
2411 png_byte buf[7];
2412 png_time mod_time;
2413
2414 png_debug(1, "in png_handle_tIME");
2415
2416 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2417 png_chunk_error(png_ptr, "missing IHDR");
2418
2419 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tIME) != 0)
2420 {
2421 png_crc_finish(png_ptr, length);
2422 png_chunk_benign_error(png_ptr, "duplicate");
2423 return;
2424 }
2425
2426 if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2427 png_ptr->mode |= PNG_AFTER_IDAT;
2428
2429 if (length != 7)
2430 {
2431 png_crc_finish(png_ptr, length);
2432 png_chunk_benign_error(png_ptr, "invalid");
2433 return;
2434 }
2435
2436 png_crc_read(png_ptr, buf, 7);
2437
2438 if (png_crc_finish(png_ptr, 0) != 0)
2439 return;
2440
2441 mod_time.second = buf[6];
2442 mod_time.minute = buf[5];
2443 mod_time.hour = buf[4];
2444 mod_time.day = buf[3];
2445 mod_time.month = buf[2];
2446 mod_time.year = png_get_uint_16(buf);
2447
2448 png_set_tIME(png_ptr, info_ptr, &mod_time);
2449 }
2450 #endif
2451
2452 #ifdef PNG_READ_tEXt_SUPPORTED
2453 /* Note: this does not properly handle chunks that are > 64K under DOS */
2454 void /* PRIVATE */
2455 png_handle_tEXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2456 {
2457 png_text text_info;
2458 png_bytep buffer;
2459 png_charp key;
2460 png_charp text;
2461 png_uint_32 skip = 0;
2462
2463 png_debug(1, "in png_handle_tEXt");
2464
2465 #ifdef PNG_USER_LIMITS_SUPPORTED
2466 if (png_ptr->user_chunk_cache_max != 0)
2467 {
2468 if (png_ptr->user_chunk_cache_max == 1)
2469 {
2470 png_crc_finish(png_ptr, length);
2471 return;
2472 }
2473
2474 if (--png_ptr->user_chunk_cache_max == 1)
2475 {
2476 png_crc_finish(png_ptr, length);
2477 png_chunk_benign_error(png_ptr, "no space in chunk cache");
2478 return;
2479 }
2480 }
2481 #endif
2482
2483 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2484 png_chunk_error(png_ptr, "missing IHDR");
2485
2486 if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2487 png_ptr->mode |= PNG_AFTER_IDAT;
2488
2489 #ifdef PNG_MAX_MALLOC_64K
2490 if (length > 65535U)
2491 {
2492 png_crc_finish(png_ptr, length);
2493 png_chunk_benign_error(png_ptr, "too large to fit in memory");
2494 return;
2495 }
2496 #endif
2497
2498 buffer = png_read_buffer(png_ptr, length+1, 1/*warn*/);
2499
2500 if (buffer == NULL)
2501 {
2502 png_chunk_benign_error(png_ptr, "out of memory");
2503 return;
2504 }
2505
2506 png_crc_read(png_ptr, buffer, length);
2507
2508 if (png_crc_finish(png_ptr, skip) != 0)
2509 return;
2510
2511 key = (png_charp)buffer;
2512 key[length] = 0;
2513
2514 for (text = key; *text; text++)
2515 /* Empty loop to find end of key */ ;
2516
2517 if (text != key + length)
2518 text++;
2519
2520 text_info.compression = PNG_TEXT_COMPRESSION_NONE;
2521 text_info.key = key;
2522 text_info.lang = NULL;
2523 text_info.lang_key = NULL;
2524 text_info.itxt_length = 0;
2525 text_info.text = text;
2526 text_info.text_length = strlen(text);
2527
2528 if (png_set_text_2(png_ptr, info_ptr, &text_info, 1) != 0)
2529 png_warning(png_ptr, "Insufficient memory to process text chunk");
2530 }
2531 #endif
2532
2533 #ifdef PNG_READ_zTXt_SUPPORTED
2534 /* Note: this does not correctly handle chunks that are > 64K under DOS */
2535 void /* PRIVATE */
2536 png_handle_zTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2537 {
2538 png_const_charp errmsg = NULL;
2539 png_bytep buffer;
2540 png_uint_32 keyword_length;
2541
2542 png_debug(1, "in png_handle_zTXt");
2543
2544 #ifdef PNG_USER_LIMITS_SUPPORTED
2545 if (png_ptr->user_chunk_cache_max != 0)
2546 {
2547 if (png_ptr->user_chunk_cache_max == 1)
2548 {
2549 png_crc_finish(png_ptr, length);
2550 return;
2551 }
2552
2553 if (--png_ptr->user_chunk_cache_max == 1)
2554 {
2555 png_crc_finish(png_ptr, length);
2556 png_chunk_benign_error(png_ptr, "no space in chunk cache");
2557 return;
2558 }
2559 }
2560 #endif
2561
2562 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2563 png_chunk_error(png_ptr, "missing IHDR");
2564
2565 if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2566 png_ptr->mode |= PNG_AFTER_IDAT;
2567
2568 buffer = png_read_buffer(png_ptr, length, 2/*silent*/);
2569
2570 if (buffer == NULL)
2571 {
2572 png_crc_finish(png_ptr, length);
2573 png_chunk_benign_error(png_ptr, "out of memory");
2574 return;
2575 }
2576
2577 png_crc_read(png_ptr, buffer, length);
2578
2579 if (png_crc_finish(png_ptr, 0) != 0)
2580 return;
2581
2582 /* TODO: also check that the keyword contents match the spec! */
2583 for (keyword_length = 0;
2584 keyword_length < length && buffer[keyword_length] != 0;
2585 ++keyword_length)
2586 /* Empty loop to find end of name */ ;
2587
2588 if (keyword_length > 79 || keyword_length < 1)
2589 errmsg = "bad keyword";
2590
2591 /* zTXt must have some LZ data after the keyword, although it may expand to
2592 * zero bytes; we need a '\0' at the end of the keyword, the compression type
2593 * then the LZ data:
2594 */
2595 else if (keyword_length + 3 > length)
2596 errmsg = "truncated";
2597
2598 else if (buffer[keyword_length+1] != PNG_COMPRESSION_TYPE_BASE)
2599 errmsg = "unknown compression type";
2600
2601 else
2602 {
2603 png_alloc_size_t uncompressed_length = PNG_SIZE_MAX;
2604
2605 /* TODO: at present png_decompress_chunk imposes a single application
2606 * level memory limit, this should be split to different values for iCCP
2607 * and text chunks.
2608 */
2609 if (png_decompress_chunk(png_ptr, length, keyword_length+2,
2610 &uncompressed_length, 1/*terminate*/) == Z_STREAM_END)
2611 {
2612 png_text text;
2613
2614 /* It worked; png_ptr->read_buffer now looks like a tEXt chunk except
2615 * for the extra compression type byte and the fact that it isn't
2616 * necessarily '\0' terminated.
2617 */
2618 buffer = png_ptr->read_buffer;
2619 buffer[uncompressed_length+(keyword_length+2)] = 0;
2620
2621 text.compression = PNG_TEXT_COMPRESSION_zTXt;
2622 text.key = (png_charp)buffer;
2623 text.text = (png_charp)(buffer + keyword_length+2);
2624 text.text_length = uncompressed_length;
2625 text.itxt_length = 0;
2626 text.lang = NULL;
2627 text.lang_key = NULL;
2628
2629 if (png_set_text_2(png_ptr, info_ptr, &text, 1) != 0)
2630 errmsg = "insufficient memory";
2631 }
2632
2633 else
2634 errmsg = png_ptr->zstream.msg;
2635 }
2636
2637 if (errmsg != NULL)
2638 png_chunk_benign_error(png_ptr, errmsg);
2639 }
2640 #endif
2641
2642 #ifdef PNG_READ_iTXt_SUPPORTED
2643 /* Note: this does not correctly handle chunks that are > 64K under DOS */
2644 void /* PRIVATE */
2645 png_handle_iTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2646 {
2647 png_const_charp errmsg = NULL;
2648 png_bytep buffer;
2649 png_uint_32 prefix_length;
2650
2651 png_debug(1, "in png_handle_iTXt");
2652
2653 #ifdef PNG_USER_LIMITS_SUPPORTED
2654 if (png_ptr->user_chunk_cache_max != 0)
2655 {
2656 if (png_ptr->user_chunk_cache_max == 1)
2657 {
2658 png_crc_finish(png_ptr, length);
2659 return;
2660 }
2661
2662 if (--png_ptr->user_chunk_cache_max == 1)
2663 {
2664 png_crc_finish(png_ptr, length);
2665 png_chunk_benign_error(png_ptr, "no space in chunk cache");
2666 return;
2667 }
2668 }
2669 #endif
2670
2671 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2672 png_chunk_error(png_ptr, "missing IHDR");
2673
2674 if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2675 png_ptr->mode |= PNG_AFTER_IDAT;
2676
2677 buffer = png_read_buffer(png_ptr, length+1, 1/*warn*/);
2678
2679 if (buffer == NULL)
2680 {
2681 png_crc_finish(png_ptr, length);
2682 png_chunk_benign_error(png_ptr, "out of memory");
2683 return;
2684 }
2685
2686 png_crc_read(png_ptr, buffer, length);
2687
2688 if (png_crc_finish(png_ptr, 0) != 0)
2689 return;
2690
2691 /* First the keyword. */
2692 for (prefix_length=0;
2693 prefix_length < length && buffer[prefix_length] != 0;
2694 ++prefix_length)
2695 /* Empty loop */ ;
2696
2697 /* Perform a basic check on the keyword length here. */
2698 if (prefix_length > 79 || prefix_length < 1)
2699 errmsg = "bad keyword";
2700
2701 /* Expect keyword, compression flag, compression type, language, translated
2702 * keyword (both may be empty but are 0 terminated) then the text, which may
2703 * be empty.
2704 */
2705 else if (prefix_length + 5 > length)
2706 errmsg = "truncated";
2707
2708 else if (buffer[prefix_length+1] == 0 ||
2709 (buffer[prefix_length+1] == 1 &&
2710 buffer[prefix_length+2] == PNG_COMPRESSION_TYPE_BASE))
2711 {
2712 int compressed = buffer[prefix_length+1] != 0;
2713 png_uint_32 language_offset, translated_keyword_offset;
2714 png_alloc_size_t uncompressed_length = 0;
2715
2716 /* Now the language tag */
2717 prefix_length += 3;
2718 language_offset = prefix_length;
2719
2720 for (; prefix_length < length && buffer[prefix_length] != 0;
2721 ++prefix_length)
2722 /* Empty loop */ ;
2723
2724 /* WARNING: the length may be invalid here, this is checked below. */
2725 translated_keyword_offset = ++prefix_length;
2726
2727 for (; prefix_length < length && buffer[prefix_length] != 0;
2728 ++prefix_length)
2729 /* Empty loop */ ;
2730
2731 /* prefix_length should now be at the trailing '\0' of the translated
2732 * keyword, but it may already be over the end. None of this arithmetic
2733 * can overflow because chunks are at most 2^31 bytes long, but on 16-bit
2734 * systems the available allocation may overflow.
2735 */
2736 ++prefix_length;
2737
2738 if (compressed == 0 && prefix_length <= length)
2739 uncompressed_length = length - prefix_length;
2740
2741 else if (compressed != 0 && prefix_length < length)
2742 {
2743 uncompressed_length = PNG_SIZE_MAX;
2744
2745 /* TODO: at present png_decompress_chunk imposes a single application
2746 * level memory limit, this should be split to different values for
2747 * iCCP and text chunks.
2748 */
2749 if (png_decompress_chunk(png_ptr, length, prefix_length,
2750 &uncompressed_length, 1/*terminate*/) == Z_STREAM_END)
2751 buffer = png_ptr->read_buffer;
2752
2753 else
2754 errmsg = png_ptr->zstream.msg;
2755 }
2756
2757 else
2758 errmsg = "truncated";
2759
2760 if (errmsg == NULL)
2761 {
2762 png_text text;
2763
2764 buffer[uncompressed_length+prefix_length] = 0;
2765
2766 if (compressed == 0)
2767 text.compression = PNG_ITXT_COMPRESSION_NONE;
2768
2769 else
2770 text.compression = PNG_ITXT_COMPRESSION_zTXt;
2771
2772 text.key = (png_charp)buffer;
2773 text.lang = (png_charp)buffer + language_offset;
2774 text.lang_key = (png_charp)buffer + translated_keyword_offset;
2775 text.text = (png_charp)buffer + prefix_length;
2776 text.text_length = 0;
2777 text.itxt_length = uncompressed_length;
2778
2779 if (png_set_text_2(png_ptr, info_ptr, &text, 1) != 0)
2780 errmsg = "insufficient memory";
2781 }
2782 }
2783
2784 else
2785 errmsg = "bad compression info";
2786
2787 if (errmsg != NULL)
2788 png_chunk_benign_error(png_ptr, errmsg);
2789 }
2790 #endif
2791
2792 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
2793 /* Utility function for png_handle_unknown; set up png_ptr::unknown_chunk */
2794 static int
2795 png_cache_unknown_chunk(png_structrp png_ptr, png_uint_32 length)
2796 {
2797 png_alloc_size_t limit = PNG_SIZE_MAX;
2798
2799 if (png_ptr->unknown_chunk.data != NULL)
2800 {
2801 png_free(png_ptr, png_ptr->unknown_chunk.data);
2802 png_ptr->unknown_chunk.data = NULL;
2803 }
2804
2805 # ifdef PNG_SET_USER_LIMITS_SUPPORTED
2806 if (png_ptr->user_chunk_malloc_max > 0 &&
2807 png_ptr->user_chunk_malloc_max < limit)
2808 limit = png_ptr->user_chunk_malloc_max;
2809
2810 # elif PNG_USER_CHUNK_MALLOC_MAX > 0
2811 if (PNG_USER_CHUNK_MALLOC_MAX < limit)
2812 limit = PNG_USER_CHUNK_MALLOC_MAX;
2813 # endif
2814
2815 if (length <= limit)
2816 {
2817 PNG_CSTRING_FROM_CHUNK(png_ptr->unknown_chunk.name, png_ptr->chunk_name);
2818 /* The following is safe because of the PNG_SIZE_MAX init above */
2819 png_ptr->unknown_chunk.size = (png_size_t)length/*SAFE*/;
2820 /* 'mode' is a flag array, only the bottom four bits matter here */
2821 png_ptr->unknown_chunk.location = (png_byte)png_ptr->mode/*SAFE*/;
2822
2823 if (length == 0)
2824 png_ptr->unknown_chunk.data = NULL;
2825
2826 else
2827 {
2828 /* Do a 'warn' here - it is handled below. */
2829 png_ptr->unknown_chunk.data = png_voidcast(png_bytep,
2830 png_malloc_warn(png_ptr, length));
2831 }
2832 }
2833
2834 if (png_ptr->unknown_chunk.data == NULL && length > 0)
2835 {
2836 /* This is benign because we clean up correctly */
2837 png_crc_finish(png_ptr, length);
2838 png_chunk_benign_error(png_ptr, "unknown chunk exceeds memory limits");
2839 return 0;
2840 }
2841
2842 else
2843 {
2844 if (length > 0)
2845 png_crc_read(png_ptr, png_ptr->unknown_chunk.data, length);
2846 png_crc_finish(png_ptr, 0);
2847 return 1;
2848 }
2849 }
2850 #endif /* READ_UNKNOWN_CHUNKS */
2851
2852 /* Handle an unknown, or known but disabled, chunk */
2853 void /* PRIVATE */
2854 png_handle_unknown(png_structrp png_ptr, png_inforp info_ptr,
2855 png_uint_32 length, int keep)
2856 {
2857 int handled = 0; /* the chunk was handled */
2858
2859 png_debug(1, "in png_handle_unknown");
2860
2861 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
2862 /* NOTE: this code is based on the code in libpng-1.4.12 except for fixing
2863 * the bug which meant that setting a non-default behavior for a specific
2864 * chunk would be ignored (the default was always used unless a user
2865 * callback was installed).
2866 *
2867 * 'keep' is the value from the png_chunk_unknown_handling, the setting for
2868 * this specific chunk_name, if PNG_HANDLE_AS_UNKNOWN_SUPPORTED, if not it
2869 * will always be PNG_HANDLE_CHUNK_AS_DEFAULT and it needs to be set here.
2870 * This is just an optimization to avoid multiple calls to the lookup
2871 * function.
2872 */
2873 # ifndef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
2874 # ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
2875 keep = png_chunk_unknown_handling(png_ptr, png_ptr->chunk_name);
2876 # endif
2877 # endif
2878
2879 /* One of the following methods will read the chunk or skip it (at least one
2880 * of these is always defined because this is the only way to switch on
2881 * PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
2882 */
2883 # ifdef PNG_READ_USER_CHUNKS_SUPPORTED
2884 /* The user callback takes precedence over the chunk keep value, but the
2885 * keep value is still required to validate a save of a critical chunk.
2886 */
2887 if (png_ptr->read_user_chunk_fn != NULL)
2888 {
2889 if (png_cache_unknown_chunk(png_ptr, length) != 0)
2890 {
2891 /* Callback to user unknown chunk handler */
2892 int ret = (*(png_ptr->read_user_chunk_fn))(png_ptr,
2893 &png_ptr->unknown_chunk);
2894
2895 /* ret is:
2896 * negative: An error occurred; png_chunk_error will be called.
2897 * zero: The chunk was not handled, the chunk will be discarded
2898 * unless png_set_keep_unknown_chunks has been used to set
2899 * a 'keep' behavior for this particular chunk, in which
2900 * case that will be used. A critical chunk will cause an
2901 * error at this point unless it is to be saved.
2902 * positive: The chunk was handled, libpng will ignore/discard it.
2903 */
2904 if (ret < 0)
2905 png_chunk_error(png_ptr, "error in user chunk");
2906
2907 else if (ret == 0)
2908 {
2909 /* If the keep value is 'default' or 'never' override it, but
2910 * still error out on critical chunks unless the keep value is
2911 * 'always' While this is weird it is the behavior in 1.4.12.
2912 * A possible improvement would be to obey the value set for the
2913 * chunk, but this would be an API change that would probably
2914 * damage some applications.
2915 *
2916 * The png_app_warning below catches the case that matters, where
2917 * the application has not set specific save or ignore for this
2918 * chunk or global save or ignore.
2919 */
2920 if (keep < PNG_HANDLE_CHUNK_IF_SAFE)
2921 {
2922 # ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
2923 if (png_ptr->unknown_default < PNG_HANDLE_CHUNK_IF_SAFE)
2924 {
2925 png_chunk_warning(png_ptr, "Saving unknown chunk:");
2926 png_app_warning(png_ptr,
2927 "forcing save of an unhandled chunk;"
2928 " please call png_set_keep_unknown_chunks");
2929 /* with keep = PNG_HANDLE_CHUNK_IF_SAFE */
2930 }
2931 # endif
2932 keep = PNG_HANDLE_CHUNK_IF_SAFE;
2933 }
2934 }
2935
2936 else /* chunk was handled */
2937 {
2938 handled = 1;
2939 /* Critical chunks can be safely discarded at this point. */
2940 keep = PNG_HANDLE_CHUNK_NEVER;
2941 }
2942 }
2943
2944 else
2945 keep = PNG_HANDLE_CHUNK_NEVER; /* insufficient memory */
2946 }
2947
2948 else
2949 /* Use the SAVE_UNKNOWN_CHUNKS code or skip the chunk */
2950 # endif /* READ_USER_CHUNKS */
2951
2952 # ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED
2953 {
2954 /* keep is currently just the per-chunk setting, if there was no
2955 * setting change it to the global default now (not that this may
2956 * still be AS_DEFAULT) then obtain the cache of the chunk if required,
2957 * if not simply skip the chunk.
2958 */
2959 if (keep == PNG_HANDLE_CHUNK_AS_DEFAULT)
2960 keep = png_ptr->unknown_default;
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 if (png_cache_unknown_chunk(png_ptr, length) == 0)
2967 keep = PNG_HANDLE_CHUNK_NEVER;
2968 }
2969
2970 else
2971 png_crc_finish(png_ptr, length);
2972 }
2973 # else
2974 # ifndef PNG_READ_USER_CHUNKS_SUPPORTED
2975 # error no method to support READ_UNKNOWN_CHUNKS
2976 # endif
2977
2978 {
2979 /* If here there is no read callback pointer set and no support is
2980 * compiled in to just save the unknown chunks, so simply skip this
2981 * chunk. If 'keep' is something other than AS_DEFAULT or NEVER then
2982 * the app has erroneously asked for unknown chunk saving when there
2983 * is no support.
2984 */
2985 if (keep > PNG_HANDLE_CHUNK_NEVER)
2986 png_app_error(png_ptr, "no unknown chunk support available");
2987
2988 png_crc_finish(png_ptr, length);
2989 }
2990 # endif
2991
2992 # ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
2993 /* Now store the chunk in the chunk list if appropriate, and if the limits
2994 * permit it.
2995 */
2996 if (keep == PNG_HANDLE_CHUNK_ALWAYS ||
2997 (keep == PNG_HANDLE_CHUNK_IF_SAFE &&
2998 PNG_CHUNK_ANCILLARY(png_ptr->chunk_name)))
2999 {
3000 # ifdef PNG_USER_LIMITS_SUPPORTED
3001 switch (png_ptr->user_chunk_cache_max)
3002 {
3003 case 2:
3004 png_ptr->user_chunk_cache_max = 1;
3005 png_chunk_benign_error(png_ptr, "no space in chunk cache");
3006 /* FALL THROUGH */
3007 case 1:
3008 /* NOTE: prior to 1.6.0 this case resulted in an unknown critical
3009 * chunk being skipped, now there will be a hard error below.
3010 */
3011 break;
3012
3013 default: /* not at limit */
3014 --(png_ptr->user_chunk_cache_max);
3015 /* FALL THROUGH */
3016 case 0: /* no limit */
3017 # endif /* USER_LIMITS */
3018 /* Here when the limit isn't reached or when limits are compiled
3019 * out; store the chunk.
3020 */
3021 png_set_unknown_chunks(png_ptr, info_ptr,
3022 &png_ptr->unknown_chunk, 1);
3023 handled = 1;
3024 # ifdef PNG_USER_LIMITS_SUPPORTED
3025 break;
3026 }
3027 # endif
3028 }
3029 # else /* no store support: the chunk must be handled by the user callback */
3030 PNG_UNUSED(info_ptr)
3031 # endif
3032
3033 /* Regardless of the error handling below the cached data (if any) can be
3034 * freed now. Notice that the data is not freed if there is a png_error, but
3035 * it will be freed by destroy_read_struct.
3036 */
3037 if (png_ptr->unknown_chunk.data != NULL)
3038 png_free(png_ptr, png_ptr->unknown_chunk.data);
3039 png_ptr->unknown_chunk.data = NULL;
3040
3041 #else /* !PNG_READ_UNKNOWN_CHUNKS_SUPPORTED */
3042 /* There is no support to read an unknown chunk, so just skip it. */
3043 png_crc_finish(png_ptr, length);
3044 PNG_UNUSED(info_ptr)
3045 PNG_UNUSED(keep)
3046 #endif /* !READ_UNKNOWN_CHUNKS */
3047
3048 /* Check for unhandled critical chunks */
3049 if (handled == 0 && PNG_CHUNK_CRITICAL(png_ptr->chunk_name))
3050 png_chunk_error(png_ptr, "unhandled critical chunk");
3051 }
3052
3053 /* This function is called to verify that a chunk name is valid.
3054 * This function can't have the "critical chunk check" incorporated
3055 * into it, since in the future we will need to be able to call user
3056 * functions to handle unknown critical chunks after we check that
3057 * the chunk name itself is valid.
3058 */
3059
3060 /* Bit hacking: the test for an invalid byte in the 4 byte chunk name is:
3061 *
3062 * ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97))
3063 */
3064
3065 void /* PRIVATE */
3066 png_check_chunk_name(png_structrp png_ptr, png_uint_32 chunk_name)
3067 {
3068 int i;
3069
3070 png_debug(1, "in png_check_chunk_name");
3071
3072 for (i=1; i<=4; ++i)
3073 {
3074 int c = chunk_name & 0xff;
3075
3076 if (c < 65 || c > 122 || (c > 90 && c < 97))
3077 png_chunk_error(png_ptr, "invalid chunk type");
3078
3079 chunk_name >>= 8;
3080 }
3081 }
3082
3083 /* Combines the row recently read in with the existing pixels in the row. This
3084 * routine takes care of alpha and transparency if requested. This routine also
3085 * handles the two methods of progressive display of interlaced images,
3086 * depending on the 'display' value; if 'display' is true then the whole row
3087 * (dp) is filled from the start by replicating the available pixels. If
3088 * 'display' is false only those pixels present in the pass are filled in.
3089 */
3090 void /* PRIVATE */
3091 png_combine_row(png_const_structrp png_ptr, png_bytep dp, int display)
3092 {
3093 unsigned int pixel_depth = png_ptr->transformed_pixel_depth;
3094 png_const_bytep sp = png_ptr->row_buf + 1;
3095 png_alloc_size_t row_width = png_ptr->width;
3096 unsigned int pass = png_ptr->pass;
3097 png_bytep end_ptr = 0;
3098 png_byte end_byte = 0;
3099 unsigned int end_mask;
3100
3101 png_debug(1, "in png_combine_row");
3102
3103 /* Added in 1.5.6: it should not be possible to enter this routine until at
3104 * least one row has been read from the PNG data and transformed.
3105 */
3106 if (pixel_depth == 0)
3107 png_error(png_ptr, "internal row logic error");
3108
3109 /* Added in 1.5.4: the pixel depth should match the information returned by
3110 * any call to png_read_update_info at this point. Do not continue if we got
3111 * this wrong.
3112 */
3113 if (png_ptr->info_rowbytes != 0 && png_ptr->info_rowbytes !=
3114 PNG_ROWBYTES(pixel_depth, row_width))
3115 png_error(png_ptr, "internal row size calculation error");
3116
3117 /* Don't expect this to ever happen: */
3118 if (row_width == 0)
3119 png_error(png_ptr, "internal row width error");
3120
3121 /* Preserve the last byte in cases where only part of it will be overwritten,
3122 * the multiply below may overflow, we don't care because ANSI-C guarantees
3123 * we get the low bits.
3124 */
3125 end_mask = (pixel_depth * row_width) & 7;
3126 if (end_mask != 0)
3127 {
3128 /* end_ptr == NULL is a flag to say do nothing */
3129 end_ptr = dp + PNG_ROWBYTES(pixel_depth, row_width) - 1;
3130 end_byte = *end_ptr;
3131 # ifdef PNG_READ_PACKSWAP_SUPPORTED
3132 if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
3133 /* little-endian byte */
3134 end_mask = (unsigned int)(0xff << end_mask);
3135
3136 else /* big-endian byte */
3137 # endif
3138 end_mask = 0xff >> end_mask;
3139 /* end_mask is now the bits to *keep* from the destination row */
3140 }
3141
3142 /* For non-interlaced images this reduces to a memcpy(). A memcpy()
3143 * will also happen if interlacing isn't supported or if the application
3144 * does not call png_set_interlace_handling(). In the latter cases the
3145 * caller just gets a sequence of the unexpanded rows from each interlace
3146 * pass.
3147 */
3148 #ifdef PNG_READ_INTERLACING_SUPPORTED
3149 if (png_ptr->interlaced != 0 &&
3150 (png_ptr->transformations & PNG_INTERLACE) != 0 &&
3151 pass < 6 && (display == 0 ||
3152 /* The following copies everything for 'display' on passes 0, 2 and 4. */
3153 (display == 1 && (pass & 1) != 0)))
3154 {
3155 /* Narrow images may have no bits in a pass; the caller should handle
3156 * this, but this test is cheap:
3157 */
3158 if (row_width <= PNG_PASS_START_COL(pass))
3159 return;
3160
3161 if (pixel_depth < 8)
3162 {
3163 /* For pixel depths up to 4 bpp the 8-pixel mask can be expanded to fit
3164 * into 32 bits, then a single loop over the bytes using the four byte
3165 * values in the 32-bit mask can be used. For the 'display' option the
3166 * expanded mask may also not require any masking within a byte. To
3167 * make this work the PACKSWAP option must be taken into account - it
3168 * simply requires the pixels to be reversed in each byte.
3169 *
3170 * The 'regular' case requires a mask for each of the first 6 passes,
3171 * the 'display' case does a copy for the even passes in the range
3172 * 0..6. This has already been handled in the test above.
3173 *
3174 * The masks are arranged as four bytes with the first byte to use in
3175 * the lowest bits (little-endian) regardless of the order (PACKSWAP or
3176 * not) of the pixels in each byte.
3177 *
3178 * NOTE: the whole of this logic depends on the caller of this function
3179 * only calling it on rows appropriate to the pass. This function only
3180 * understands the 'x' logic; the 'y' logic is handled by the caller.
3181 *
3182 * The following defines allow generation of compile time constant bit
3183 * masks for each pixel depth and each possibility of swapped or not
3184 * swapped bytes. Pass 'p' is in the range 0..6; 'x', a pixel index,
3185 * is in the range 0..7; and the result is 1 if the pixel is to be
3186 * copied in the pass, 0 if not. 'S' is for the sparkle method, 'B'
3187 * for the block method.
3188 *
3189 * With some compilers a compile time expression of the general form:
3190 *
3191 * (shift >= 32) ? (a >> (shift-32)) : (b >> shift)
3192 *
3193 * Produces warnings with values of 'shift' in the range 33 to 63
3194 * because the right hand side of the ?: expression is evaluated by
3195 * the compiler even though it isn't used. Microsoft Visual C (various
3196 * versions) and the Intel C compiler are known to do this. To avoid
3197 * this the following macros are used in 1.5.6. This is a temporary
3198 * solution to avoid destabilizing the code during the release process.
3199 */
3200 # if PNG_USE_COMPILE_TIME_MASKS
3201 # define PNG_LSR(x,s) ((x)>>((s) & 0x1f))
3202 # define PNG_LSL(x,s) ((x)<<((s) & 0x1f))
3203 # else
3204 # define PNG_LSR(x,s) ((x)>>(s))
3205 # define PNG_LSL(x,s) ((x)<<(s))
3206 # endif
3207 # define S_COPY(p,x) (((p)<4 ? PNG_LSR(0x80088822,(3-(p))*8+(7-(x))) :\
3208 PNG_LSR(0xaa55ff00,(7-(p))*8+(7-(x)))) & 1)
3209 # define B_COPY(p,x) (((p)<4 ? PNG_LSR(0xff0fff33,(3-(p))*8+(7-(x))) :\
3210 PNG_LSR(0xff55ff00,(7-(p))*8+(7-(x)))) & 1)
3211
3212 /* Return a mask for pass 'p' pixel 'x' at depth 'd'. The mask is
3213 * little endian - the first pixel is at bit 0 - however the extra
3214 * parameter 's' can be set to cause the mask position to be swapped
3215 * within each byte, to match the PNG format. This is done by XOR of
3216 * the shift with 7, 6 or 4 for bit depths 1, 2 and 4.
3217 */
3218 # define PIXEL_MASK(p,x,d,s) \
3219 (PNG_LSL(((PNG_LSL(1U,(d)))-1),(((x)*(d))^((s)?8-(d):0))))
3220
3221 /* Hence generate the appropriate 'block' or 'sparkle' pixel copy mask.
3222 */
3223 # define S_MASKx(p,x,d,s) (S_COPY(p,x)?PIXEL_MASK(p,x,d,s):0)
3224 # define B_MASKx(p,x,d,s) (B_COPY(p,x)?PIXEL_MASK(p,x,d,s):0)
3225
3226 /* Combine 8 of these to get the full mask. For the 1-bpp and 2-bpp
3227 * cases the result needs replicating, for the 4-bpp case the above
3228 * generates a full 32 bits.
3229 */
3230 # define MASK_EXPAND(m,d) ((m)*((d)==1?0x01010101:((d)==2?0x00010001:1)))
3231
3232 # define S_MASK(p,d,s) MASK_EXPAND(S_MASKx(p,0,d,s) + S_MASKx(p,1,d,s) +\
3233 S_MASKx(p,2,d,s) + S_MASKx(p,3,d,s) + S_MASKx(p,4,d,s) +\
3234 S_MASKx(p,5,d,s) + S_MASKx(p,6,d,s) + S_MASKx(p,7,d,s), d)
3235
3236 # define B_MASK(p,d,s) MASK_EXPAND(B_MASKx(p,0,d,s) + B_MASKx(p,1,d,s) +\
3237 B_MASKx(p,2,d,s) + B_MASKx(p,3,d,s) + B_MASKx(p,4,d,s) +\
3238 B_MASKx(p,5,d,s) + B_MASKx(p,6,d,s) + B_MASKx(p,7,d,s), d)
3239
3240 #if PNG_USE_COMPILE_TIME_MASKS
3241 /* Utility macros to construct all the masks for a depth/swap
3242 * combination. The 's' parameter says whether the format is PNG
3243 * (big endian bytes) or not. Only the three odd-numbered passes are
3244 * required for the display/block algorithm.
3245 */
3246 # define S_MASKS(d,s) { S_MASK(0,d,s), S_MASK(1,d,s), S_MASK(2,d,s),\
3247 S_MASK(3,d,s), S_MASK(4,d,s), S_MASK(5,d,s) }
3248
3249 # define B_MASKS(d,s) { B_MASK(1,d,s), B_MASK(3,d,s), B_MASK(5,d,s) }
3250
3251 # define DEPTH_INDEX(d) ((d)==1?0:((d)==2?1:2))
3252
3253 /* Hence the pre-compiled masks indexed by PACKSWAP (or not), depth and
3254 * then pass:
3255 */
3256 static PNG_CONST png_uint_32 row_mask[2/*PACKSWAP*/][3/*depth*/][6] =
3257 {
3258 /* Little-endian byte masks for PACKSWAP */
3259 { S_MASKS(1,0), S_MASKS(2,0), S_MASKS(4,0) },
3260 /* Normal (big-endian byte) masks - PNG format */
3261 { S_MASKS(1,1), S_MASKS(2,1), S_MASKS(4,1) }
3262 };
3263
3264 /* display_mask has only three entries for the odd passes, so index by
3265 * pass>>1.
3266 */
3267 static PNG_CONST png_uint_32 display_mask[2][3][3] =
3268 {
3269 /* Little-endian byte masks for PACKSWAP */
3270 { B_MASKS(1,0), B_MASKS(2,0), B_MASKS(4,0) },
3271 /* Normal (big-endian byte) masks - PNG format */
3272 { B_MASKS(1,1), B_MASKS(2,1), B_MASKS(4,1) }
3273 };
3274
3275 # define MASK(pass,depth,display,png)\
3276 ((display)?display_mask[png][DEPTH_INDEX(depth)][pass>>1]:\
3277 row_mask[png][DEPTH_INDEX(depth)][pass])
3278
3279 #else /* !PNG_USE_COMPILE_TIME_MASKS */
3280 /* This is the runtime alternative: it seems unlikely that this will
3281 * ever be either smaller or faster than the compile time approach.
3282 */
3283 # define MASK(pass,depth,display,png)\
3284 ((display)?B_MASK(pass,depth,png):S_MASK(pass,depth,png))
3285 #endif /* !USE_COMPILE_TIME_MASKS */
3286
3287 /* Use the appropriate mask to copy the required bits. In some cases
3288 * the byte mask will be 0 or 0xff; optimize these cases. row_width is
3289 * the number of pixels, but the code copies bytes, so it is necessary
3290 * to special case the end.
3291 */
3292 png_uint_32 pixels_per_byte = 8 / pixel_depth;
3293 png_uint_32 mask;
3294
3295 # ifdef PNG_READ_PACKSWAP_SUPPORTED
3296 if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
3297 mask = MASK(pass, pixel_depth, display, 0);
3298
3299 else
3300 # endif
3301 mask = MASK(pass, pixel_depth, display, 1);
3302
3303 for (;;)
3304 {
3305 png_uint_32 m;
3306
3307 /* It doesn't matter in the following if png_uint_32 has more than
3308 * 32 bits because the high bits always match those in m<<24; it is,
3309 * however, essential to use OR here, not +, because of this.
3310 */
3311 m = mask;
3312 mask = (m >> 8) | (m << 24); /* rotate right to good compilers */
3313 m &= 0xff;
3314
3315 if (m != 0) /* something to copy */
3316 {
3317 if (m != 0xff)
3318 *dp = (png_byte)((*dp & ~m) | (*sp & m));
3319 else
3320 *dp = *sp;
3321 }
3322
3323 /* NOTE: this may overwrite the last byte with garbage if the image
3324 * is not an exact number of bytes wide; libpng has always done
3325 * this.
3326 */
3327 if (row_width <= pixels_per_byte)
3328 break; /* May need to restore part of the last byte */
3329
3330 row_width -= pixels_per_byte;
3331 ++dp;
3332 ++sp;
3333 }
3334 }
3335
3336 else /* pixel_depth >= 8 */
3337 {
3338 unsigned int bytes_to_copy, bytes_to_jump;
3339
3340 /* Validate the depth - it must be a multiple of 8 */
3341 if (pixel_depth & 7)
3342 png_error(png_ptr, "invalid user transform pixel depth");
3343
3344 pixel_depth >>= 3; /* now in bytes */
3345 row_width *= pixel_depth;
3346
3347 /* Regardless of pass number the Adam 7 interlace always results in a
3348 * fixed number of pixels to copy then to skip. There may be a
3349 * different number of pixels to skip at the start though.
3350 */
3351 {
3352 unsigned int offset = PNG_PASS_START_COL(pass) * pixel_depth;
3353
3354 row_width -= offset;
3355 dp += offset;
3356 sp += offset;
3357 }
3358
3359 /* Work out the bytes to copy. */
3360 if (display != 0)
3361 {
3362 /* When doing the 'block' algorithm the pixel in the pass gets
3363 * replicated to adjacent pixels. This is why the even (0,2,4,6)
3364 * passes are skipped above - the entire expanded row is copied.
3365 */
3366 bytes_to_copy = (1<<((6-pass)>>1)) * pixel_depth;
3367
3368 /* But don't allow this number to exceed the actual row width. */
3369 if (bytes_to_copy > row_width)
3370 bytes_to_copy = (unsigned int)/*SAFE*/row_width;
3371 }
3372
3373 else /* normal row; Adam7 only ever gives us one pixel to copy. */
3374 bytes_to_copy = pixel_depth;
3375
3376 /* In Adam7 there is a constant offset between where the pixels go. */
3377 bytes_to_jump = PNG_PASS_COL_OFFSET(pass) * pixel_depth;
3378
3379 /* And simply copy these bytes. Some optimization is possible here,
3380 * depending on the value of 'bytes_to_copy'. Special case the low
3381 * byte counts, which we know to be frequent.
3382 *
3383 * Notice that these cases all 'return' rather than 'break' - this
3384 * avoids an unnecessary test on whether to restore the last byte
3385 * below.
3386 */
3387 switch (bytes_to_copy)
3388 {
3389 case 1:
3390 for (;;)
3391 {
3392 *dp = *sp;
3393
3394 if (row_width <= bytes_to_jump)
3395 return;
3396
3397 dp += bytes_to_jump;
3398 sp += bytes_to_jump;
3399 row_width -= bytes_to_jump;
3400 }
3401
3402 case 2:
3403 /* There is a possibility of a partial copy at the end here; this
3404 * slows the code down somewhat.
3405 */
3406 do
3407 {
3408 dp[0] = sp[0], dp[1] = sp[1];
3409
3410 if (row_width <= bytes_to_jump)
3411 return;
3412
3413 sp += bytes_to_jump;
3414 dp += bytes_to_jump;
3415 row_width -= bytes_to_jump;
3416 }
3417 while (row_width > 1);
3418
3419 /* And there can only be one byte left at this point: */
3420 *dp = *sp;
3421 return;
3422
3423 case 3:
3424 /* This can only be the RGB case, so each copy is exactly one
3425 * pixel and it is not necessary to check for a partial copy.
3426 */
3427 for (;;)
3428 {
3429 dp[0] = sp[0], dp[1] = sp[1], dp[2] = sp[2];
3430
3431 if (row_width <= bytes_to_jump)
3432 return;
3433
3434 sp += bytes_to_jump;
3435 dp += bytes_to_jump;
3436 row_width -= bytes_to_jump;
3437 }
3438
3439 default:
3440 #if PNG_ALIGN_TYPE != PNG_ALIGN_NONE
3441 /* Check for double byte alignment and, if possible, use a
3442 * 16-bit copy. Don't attempt this for narrow images - ones that
3443 * are less than an interlace panel wide. Don't attempt it for
3444 * wide bytes_to_copy either - use the memcpy there.
3445 */
3446 if (bytes_to_copy < 16 /*else use memcpy*/ &&
3447 png_isaligned(dp, png_uint_16) &&
3448 png_isaligned(sp, png_uint_16) &&
3449 bytes_to_copy % (sizeof (png_uint_16)) == 0 &&
3450 bytes_to_jump % (sizeof (png_uint_16)) == 0)
3451 {
3452 /* Everything is aligned for png_uint_16 copies, but try for
3453 * png_uint_32 first.
3454 */
3455 if (png_isaligned(dp, png_uint_32) &&
3456 png_isaligned(sp, png_uint_32) &&
3457 bytes_to_copy % (sizeof (png_uint_32)) == 0 &&
3458 bytes_to_jump % (sizeof (png_uint_32)) == 0)
3459 {
3460 png_uint_32p dp32 = png_aligncast(png_uint_32p,dp);
3461 png_const_uint_32p sp32 = png_aligncastconst(
3462 png_const_uint_32p, sp);
3463 size_t skip = (bytes_to_jump-bytes_to_copy) /
3464 (sizeof (png_uint_32));
3465
3466 do
3467 {
3468 size_t c = bytes_to_copy;
3469 do
3470 {
3471 *dp32++ = *sp32++;
3472 c -= (sizeof (png_uint_32));
3473 }
3474 while (c > 0);
3475
3476 if (row_width <= bytes_to_jump)
3477 return;
3478
3479 dp32 += skip;
3480 sp32 += skip;
3481 row_width -= bytes_to_jump;
3482 }
3483 while (bytes_to_copy <= row_width);
3484
3485 /* Get to here when the row_width truncates the final copy.
3486 * There will be 1-3 bytes left to copy, so don't try the
3487 * 16-bit loop below.
3488 */
3489 dp = (png_bytep)dp32;
3490 sp = (png_const_bytep)sp32;
3491 do
3492 *dp++ = *sp++;
3493 while (--row_width > 0);
3494 return;
3495 }
3496
3497 /* Else do it in 16-bit quantities, but only if the size is
3498 * not too large.
3499 */
3500 else
3501 {
3502 png_uint_16p dp16 = png_aligncast(png_uint_16p, dp);
3503 png_const_uint_16p sp16 = png_aligncastconst(
3504 png_const_uint_16p, sp);
3505 size_t skip = (bytes_to_jump-bytes_to_copy) /
3506 (sizeof (png_uint_16));
3507
3508 do
3509 {
3510 size_t c = bytes_to_copy;
3511 do
3512 {
3513 *dp16++ = *sp16++;
3514 c -= (sizeof (png_uint_16));
3515 }
3516 while (c > 0);
3517
3518 if (row_width <= bytes_to_jump)
3519 return;
3520
3521 dp16 += skip;
3522 sp16 += skip;
3523 row_width -= bytes_to_jump;
3524 }
3525 while (bytes_to_copy <= row_width);
3526
3527 /* End of row - 1 byte left, bytes_to_copy > row_width: */
3528 dp = (png_bytep)dp16;
3529 sp = (png_const_bytep)sp16;
3530 do
3531 *dp++ = *sp++;
3532 while (--row_width > 0);
3533 return;
3534 }
3535 }
3536 #endif /* ALIGN_TYPE code */
3537
3538 /* The true default - use a memcpy: */
3539 for (;;)
3540 {
3541 memcpy(dp, sp, bytes_to_copy);
3542
3543 if (row_width <= bytes_to_jump)
3544 return;
3545
3546 sp += bytes_to_jump;
3547 dp += bytes_to_jump;
3548 row_width -= bytes_to_jump;
3549 if (bytes_to_copy > row_width)
3550 bytes_to_copy = (unsigned int)/*SAFE*/row_width;
3551 }
3552 }
3553
3554 /* NOT REACHED*/
3555 } /* pixel_depth >= 8 */
3556
3557 /* Here if pixel_depth < 8 to check 'end_ptr' below. */
3558 }
3559 else
3560 #endif /* READ_INTERLACING */
3561
3562 /* If here then the switch above wasn't used so just memcpy the whole row
3563 * from the temporary row buffer (notice that this overwrites the end of the
3564 * destination row if it is a partial byte.)
3565 */
3566 memcpy(dp, sp, PNG_ROWBYTES(pixel_depth, row_width));
3567
3568 /* Restore the overwritten bits from the last byte if necessary. */
3569 if (end_ptr != NULL)
3570 *end_ptr = (png_byte)((end_byte & end_mask) | (*end_ptr & ~end_mask));
3571 }
3572
3573 #ifdef PNG_READ_INTERLACING_SUPPORTED
3574 void /* PRIVATE */
3575 png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass,
3576 png_uint_32 transformations /* Because these may affect the byte layout */)
3577 {
3578 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
3579 /* Offset to next interlace block */
3580 static PNG_CONST unsigned int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
3581
3582 png_debug(1, "in png_do_read_interlace");
3583 if (row != NULL && row_info != NULL)
3584 {
3585 png_uint_32 final_width;
3586
3587 final_width = row_info->width * png_pass_inc[pass];
3588
3589 switch (row_info->pixel_depth)
3590 {
3591 case 1:
3592 {
3593 png_bytep sp = row + (png_size_t)((row_info->width - 1) >> 3);
3594 png_bytep dp = row + (png_size_t)((final_width - 1) >> 3);
3595 unsigned int sshift, dshift;
3596 unsigned int s_start, s_end;
3597 int s_inc;
3598 int jstop = (int)png_pass_inc[pass];
3599 png_byte v;
3600 png_uint_32 i;
3601 int j;
3602
3603 #ifdef PNG_READ_PACKSWAP_SUPPORTED
3604 if ((transformations & PNG_PACKSWAP) != 0)
3605 {
3606 sshift = ((row_info->width + 7) & 0x07);
3607 dshift = ((final_width + 7) & 0x07);
3608 s_start = 7;
3609 s_end = 0;
3610 s_inc = -1;
3611 }
3612
3613 else
3614 #endif
3615 {
3616 sshift = 7 - ((row_info->width + 7) & 0x07);
3617 dshift = 7 - ((final_width + 7) & 0x07);
3618 s_start = 0;
3619 s_end = 7;
3620 s_inc = 1;
3621 }
3622
3623 for (i = 0; i < row_info->width; i++)
3624 {
3625 v = (png_byte)((*sp >> sshift) & 0x01);
3626 for (j = 0; j < jstop; j++)
3627 {
3628 unsigned int tmp = *dp & (0x7f7f >> (7 - dshift));
3629 tmp |= (unsigned int)(v << dshift);
3630 *dp = (png_byte)(tmp & 0xff);
3631
3632 if (dshift == s_end)
3633 {
3634 dshift = s_start;
3635 dp--;
3636 }
3637
3638 else
3639 dshift = (unsigned int)((int)dshift + s_inc);
3640 }
3641
3642 if (sshift == s_end)
3643 {
3644 sshift = s_start;
3645 sp--;
3646 }
3647
3648 else
3649 sshift = (unsigned int)((int)sshift + s_inc);
3650 }
3651 break;
3652 }
3653
3654 case 2:
3655 {
3656 png_bytep sp = row + (png_uint_32)((row_info->width - 1) >> 2);
3657 png_bytep dp = row + (png_uint_32)((final_width - 1) >> 2);
3658 unsigned int sshift, dshift;
3659 unsigned int s_start, s_end;
3660 int s_inc;
3661 int jstop = (int)png_pass_inc[pass];
3662 png_uint_32 i;
3663
3664 #ifdef PNG_READ_PACKSWAP_SUPPORTED
3665 if ((transformations & PNG_PACKSWAP) != 0)
3666 {
3667 sshift = (((row_info->width + 3) & 0x03) << 1);
3668 dshift = (((final_width + 3) & 0x03) << 1);
3669 s_start = 6;
3670 s_end = 0;
3671 s_inc = -2;
3672 }
3673
3674 else
3675 #endif
3676 {
3677 sshift = ((3 - ((row_info->width + 3) & 0x03)) << 1);
3678 dshift = ((3 - ((final_width + 3) & 0x03)) << 1);
3679 s_start = 0;
3680 s_end = 6;
3681 s_inc = 2;
3682 }
3683
3684 for (i = 0; i < row_info->width; i++)
3685 {
3686 png_byte v;
3687 int j;
3688
3689 v = (png_byte)((*sp >> sshift) & 0x03);
3690 for (j = 0; j < jstop; j++)
3691 {
3692 unsigned int tmp = *dp & (0x3f3f >> (6 - dshift));
3693 tmp |= (unsigned int)(v << dshift);
3694 *dp = (png_byte)(tmp & 0xff);
3695
3696 if (dshift == s_end)
3697 {
3698 dshift = s_start;
3699 dp--;
3700 }
3701
3702 else
3703 dshift = (unsigned int)((int)dshift + s_inc);
3704 }
3705
3706 if (sshift == s_end)
3707 {
3708 sshift = s_start;
3709 sp--;
3710 }
3711
3712 else
3713 sshift = (unsigned int)((int)sshift + s_inc);
3714 }
3715 break;
3716 }
3717
3718 case 4:
3719 {
3720 png_bytep sp = row + (png_size_t)((row_info->width - 1) >> 1);
3721 png_bytep dp = row + (png_size_t)((final_width - 1) >> 1);
3722 unsigned int sshift, dshift;
3723 unsigned int s_start, s_end;
3724 int s_inc;
3725 png_uint_32 i;
3726 int jstop = (int)png_pass_inc[pass];
3727
3728 #ifdef PNG_READ_PACKSWAP_SUPPORTED
3729 if ((transformations & PNG_PACKSWAP) != 0)
3730 {
3731 sshift = (((row_info->width + 1) & 0x01) << 2);
3732 dshift = (((final_width + 1) & 0x01) << 2);
3733 s_start = 4;
3734 s_end = 0;
3735 s_inc = -4;
3736 }
3737
3738 else
3739 #endif
3740 {
3741 sshift = ((1 - ((row_info->width + 1) & 0x01)) << 2);
3742 dshift = ((1 - ((final_width + 1) & 0x01)) << 2);
3743 s_start = 0;
3744 s_end = 4;
3745 s_inc = 4;
3746 }
3747
3748 for (i = 0; i < row_info->width; i++)
3749 {
3750 png_byte v = (png_byte)((*sp >> sshift) & 0x0f);
3751 int j;
3752
3753 for (j = 0; j < jstop; j++)
3754 {
3755 unsigned int tmp = *dp & (0xf0f >> (4 - dshift));
3756 tmp |= (unsigned int)(v << dshift);
3757 *dp = (png_byte)(tmp & 0xff);
3758
3759 if (dshift == s_end)
3760 {
3761 dshift = s_start;
3762 dp--;
3763 }
3764
3765 else
3766 dshift = (unsigned int)((int)dshift + s_inc);
3767 }
3768
3769 if (sshift == s_end)
3770 {
3771 sshift = s_start;
3772 sp--;
3773 }
3774
3775 else
3776 sshift = (unsigned int)((int)sshift + s_inc);
3777 }
3778 break;
3779 }
3780
3781 default:
3782 {
3783 png_size_t pixel_bytes = (row_info->pixel_depth >> 3);
3784
3785 png_bytep sp = row + (png_size_t)(row_info->width - 1)
3786 * pixel_bytes;
3787
3788 png_bytep dp = row + (png_size_t)(final_width - 1) * pixel_bytes;
3789
3790 int jstop = (int)png_pass_inc[pass];
3791 png_uint_32 i;
3792
3793 for (i = 0; i < row_info->width; i++)
3794 {
3795 png_byte v[8]; /* SAFE; pixel_depth does not exceed 64 */
3796 int j;
3797
3798 memcpy(v, sp, pixel_bytes);
3799
3800 for (j = 0; j < jstop; j++)
3801 {
3802 memcpy(dp, v, pixel_bytes);
3803 dp -= pixel_bytes;
3804 }
3805
3806 sp -= pixel_bytes;
3807 }
3808 break;
3809 }
3810 }
3811
3812 row_info->width = final_width;
3813 row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, final_width);
3814 }
3815 #ifndef PNG_READ_PACKSWAP_SUPPORTED
3816 PNG_UNUSED(transformations) /* Silence compiler warning */
3817 #endif
3818 }
3819 #endif /* READ_INTERLACING */
3820
3821 static void
3822 png_read_filter_row_sub(png_row_infop row_info, png_bytep row,
3823 png_const_bytep prev_row)
3824 {
3825 png_size_t i;
3826 png_size_t istop = row_info->rowbytes;
3827 unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
3828 png_bytep rp = row + bpp;
3829
3830 PNG_UNUSED(prev_row)
3831
3832 for (i = bpp; i < istop; i++)
3833 {
3834 *rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 0xff);
3835 rp++;
3836 }
3837 }
3838
3839 static void
3840 png_read_filter_row_up(png_row_infop row_info, png_bytep row,
3841 png_const_bytep prev_row)
3842 {
3843 png_size_t i;
3844 png_size_t istop = row_info->rowbytes;
3845 png_bytep rp = row;
3846 png_const_bytep pp = prev_row;
3847
3848 for (i = 0; i < istop; i++)
3849 {
3850 *rp = (png_byte)(((int)(*rp) + (int)(*pp++)) & 0xff);
3851 rp++;
3852 }
3853 }
3854
3855 static void
3856 png_read_filter_row_avg(png_row_infop row_info, png_bytep row,
3857 png_const_bytep prev_row)
3858 {
3859 png_size_t i;
3860 png_bytep rp = row;
3861 png_const_bytep pp = prev_row;
3862 unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
3863 png_size_t istop = row_info->rowbytes - bpp;
3864
3865 for (i = 0; i < bpp; i++)
3866 {
3867 *rp = (png_byte)(((int)(*rp) +
3868 ((int)(*pp++) / 2 )) & 0xff);
3869
3870 rp++;
3871 }
3872
3873 for (i = 0; i < istop; i++)
3874 {
3875 *rp = (png_byte)(((int)(*rp) +
3876 (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff);
3877
3878 rp++;
3879 }
3880 }
3881
3882 static void
3883 png_read_filter_row_paeth_1byte_pixel(png_row_infop row_info, png_bytep row,
3884 png_const_bytep prev_row)
3885 {
3886 png_bytep rp_end = row + row_info->rowbytes;
3887 int a, c;
3888
3889 /* First pixel/byte */
3890 c = *prev_row++;
3891 a = *row + c;
3892 *row++ = (png_byte)a;
3893
3894 /* Remainder */
3895 while (row < rp_end)
3896 {
3897 int b, pa, pb, pc, p;
3898
3899 a &= 0xff; /* From previous iteration or start */
3900 b = *prev_row++;
3901
3902 p = b - c;
3903 pc = a - c;
3904
3905 #ifdef PNG_USE_ABS
3906 pa = abs(p);
3907 pb = abs(pc);
3908 pc = abs(p + pc);
3909 #else
3910 pa = p < 0 ? -p : p;
3911 pb = pc < 0 ? -pc : pc;
3912 pc = (p + pc) < 0 ? -(p + pc) : p + pc;
3913 #endif
3914
3915 /* Find the best predictor, the least of pa, pb, pc favoring the earlier
3916 * ones in the case of a tie.
3917 */
3918 if (pb < pa) pa = pb, a = b;
3919 if (pc < pa) a = c;
3920
3921 /* Calculate the current pixel in a, and move the previous row pixel to c
3922 * for the next time round the loop
3923 */
3924 c = b;
3925 a += *row;
3926 *row++ = (png_byte)a;
3927 }
3928 }
3929
3930 static void
3931 png_read_filter_row_paeth_multibyte_pixel(png_row_infop row_info, png_bytep row,
3932 png_const_bytep prev_row)
3933 {
3934 unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
3935 png_bytep rp_end = row + bpp;
3936
3937 /* Process the first pixel in the row completely (this is the same as 'up'
3938 * because there is only one candidate predictor for the first row).
3939 */
3940 while (row < rp_end)
3941 {
3942 int a = *row + *prev_row++;
3943 *row++ = (png_byte)a;
3944 }
3945
3946 /* Remainder */
3947 rp_end = rp_end + (row_info->rowbytes - bpp);
3948
3949 while (row < rp_end)
3950 {
3951 int a, b, c, pa, pb, pc, p;
3952
3953 c = *(prev_row - bpp);
3954 a = *(row - bpp);
3955 b = *prev_row++;
3956
3957 p = b - c;
3958 pc = a - c;
3959
3960 #ifdef PNG_USE_ABS
3961 pa = abs(p);
3962 pb = abs(pc);
3963 pc = abs(p + pc);
3964 #else
3965 pa = p < 0 ? -p : p;
3966 pb = pc < 0 ? -pc : pc;
3967 pc = (p + pc) < 0 ? -(p + pc) : p + pc;
3968 #endif
3969
3970 if (pb < pa) pa = pb, a = b;
3971 if (pc < pa) a = c;
3972
3973 a += *row;
3974 *row++ = (png_byte)a;
3975 }
3976 }
3977
3978 static void
3979 png_init_filter_functions(png_structrp pp)
3980 /* This function is called once for every PNG image (except for PNG images
3981 * that only use PNG_FILTER_VALUE_NONE for all rows) to set the
3982 * implementations required to reverse the filtering of PNG rows. Reversing
3983 * the filter is the first transformation performed on the row data. It is
3984 * performed in place, therefore an implementation can be selected based on
3985 * the image pixel format. If the implementation depends on image width then
3986 * take care to ensure that it works correctly if the image is interlaced -
3987 * interlacing causes the actual row width to vary.
3988 */
3989 {
3990 unsigned int bpp = (pp->pixel_depth + 7) >> 3;
3991
3992 pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub;
3993 pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up;
3994 pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg;
3995 if (bpp == 1)
3996 pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
3997 png_read_filter_row_paeth_1byte_pixel;
3998 else
3999 pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
4000 png_read_filter_row_paeth_multibyte_pixel;
4001
4002 #ifdef PNG_FILTER_OPTIMIZATIONS
4003 /* To use this define PNG_FILTER_OPTIMIZATIONS as the name of a function to
4004 * call to install hardware optimizations for the above functions; simply
4005 * replace whatever elements of the pp->read_filter[] array with a hardware
4006 * specific (or, for that matter, generic) optimization.
4007 *
4008 * To see an example of this examine what configure.ac does when
4009 * --enable-arm-neon is specified on the command line.
4010 */
4011 PNG_FILTER_OPTIMIZATIONS(pp, bpp);
4012 #endif
4013 }
4014
4015 void /* PRIVATE */
4016 png_read_filter_row(png_structrp pp, png_row_infop row_info, png_bytep row,
4017 png_const_bytep prev_row, int filter)
4018 {
4019 /* OPTIMIZATION: DO NOT MODIFY THIS FUNCTION, instead #define
4020 * PNG_FILTER_OPTIMIZATIONS to a function that overrides the generic
4021 * implementations. See png_init_filter_functions above.
4022 */
4023 if (filter > PNG_FILTER_VALUE_NONE && filter < PNG_FILTER_VALUE_LAST)
4024 {
4025 if (pp->read_filter[0] == NULL)
4026 png_init_filter_functions(pp);
4027
4028 pp->read_filter[filter-1](row_info, row, prev_row);
4029 }
4030 }
4031
4032 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
4033 void /* PRIVATE */
4034 png_read_IDAT_data(png_structrp png_ptr, png_bytep output,
4035 png_alloc_size_t avail_out)
4036 {
4037 /* Loop reading IDATs and decompressing the result into output[avail_out] */
4038 png_ptr->zstream.next_out = output;
4039 png_ptr->zstream.avail_out = 0; /* safety: set below */
4040
4041 if (output == NULL)
4042 avail_out = 0;
4043
4044 do
4045 {
4046 int ret;
4047 png_byte tmpbuf[PNG_INFLATE_BUF_SIZE];
4048
4049 if (png_ptr->zstream.avail_in == 0)
4050 {
4051 uInt avail_in;
4052 png_bytep buffer;
4053
4054 while (png_ptr->idat_size == 0)
4055 {
4056 png_crc_finish(png_ptr, 0);
4057
4058 png_ptr->idat_size = png_read_chunk_header(png_ptr);
4059 /* This is an error even in the 'check' case because the code just
4060 * consumed a non-IDAT header.
4061 */
4062 if (png_ptr->chunk_name != png_IDAT)
4063 png_error(png_ptr, "Not enough image data");
4064 }
4065
4066 avail_in = png_ptr->IDAT_read_size;
4067
4068 if (avail_in > png_ptr->idat_size)
4069 avail_in = (uInt)png_ptr->idat_size;
4070
4071 /* A PNG with a gradually increasing IDAT size will defeat this attempt
4072 * to minimize memory usage by causing lots of re-allocs, but
4073 * realistically doing IDAT_read_size re-allocs is not likely to be a
4074 * big problem.
4075 */
4076 buffer = png_read_buffer(png_ptr, avail_in, 0/*error*/);
4077
4078 png_crc_read(png_ptr, buffer, avail_in);
4079 png_ptr->idat_size -= avail_in;
4080
4081 png_ptr->zstream.next_in = buffer;
4082 png_ptr->zstream.avail_in = avail_in;
4083 }
4084
4085 /* And set up the output side. */
4086 if (output != NULL) /* standard read */
4087 {
4088 uInt out = ZLIB_IO_MAX;
4089
4090 if (out > avail_out)
4091 out = (uInt)avail_out;
4092
4093 avail_out -= out;
4094 png_ptr->zstream.avail_out = out;
4095 }
4096
4097 else /* after last row, checking for end */
4098 {
4099 png_ptr->zstream.next_out = tmpbuf;
4100 png_ptr->zstream.avail_out = (sizeof tmpbuf);
4101 }
4102
4103 /* Use NO_FLUSH; this gives zlib the maximum opportunity to optimize the
4104 * process. If the LZ stream is truncated the sequential reader will
4105 * terminally damage the stream, above, by reading the chunk header of the
4106 * following chunk (it then exits with png_error).
4107 *
4108 * TODO: deal more elegantly with truncated IDAT lists.
4109 */
4110 ret = PNG_INFLATE(png_ptr, Z_NO_FLUSH);
4111
4112 /* Take the unconsumed output back. */
4113 if (output != NULL)
4114 avail_out += png_ptr->zstream.avail_out;
4115
4116 else /* avail_out counts the extra bytes */
4117 avail_out += (sizeof tmpbuf) - png_ptr->zstream.avail_out;
4118
4119 png_ptr->zstream.avail_out = 0;
4120
4121 if (ret == Z_STREAM_END)
4122 {
4123 /* Do this for safety; we won't read any more into this row. */
4124 png_ptr->zstream.next_out = NULL;
4125
4126 png_ptr->mode |= PNG_AFTER_IDAT;
4127 png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
4128
4129 if (png_ptr->zstream.avail_in > 0 || png_ptr->idat_size > 0)
4130 png_chunk_benign_error(png_ptr, "Extra compressed data");
4131 break;
4132 }
4133
4134 if (ret != Z_OK)
4135 {
4136 png_zstream_error(png_ptr, ret);
4137
4138 if (output != NULL)
4139 png_chunk_error(png_ptr, png_ptr->zstream.msg);
4140
4141 else /* checking */
4142 {
4143 png_chunk_benign_error(png_ptr, png_ptr->zstream.msg);
4144 return;
4145 }
4146 }
4147 } while (avail_out > 0);
4148
4149 if (avail_out > 0)
4150 {
4151 /* The stream ended before the image; this is the same as too few IDATs so
4152 * should be handled the same way.
4153 */
4154 if (output != NULL)
4155 png_error(png_ptr, "Not enough image data");
4156
4157 else /* the deflate stream contained extra data */
4158 png_chunk_benign_error(png_ptr, "Too much image data");
4159 }
4160 }
4161
4162 void /* PRIVATE */
4163 png_read_finish_IDAT(png_structrp png_ptr)
4164 {
4165 /* We don't need any more data and the stream should have ended, however the
4166 * LZ end code may actually not have been processed. In this case we must
4167 * read it otherwise stray unread IDAT data or, more likely, an IDAT chunk
4168 * may still remain to be consumed.
4169 */
4170 if ((png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0)
4171 {
4172 /* The NULL causes png_read_IDAT_data to swallow any remaining bytes in
4173 * the compressed stream, but the stream may be damaged too, so even after
4174 * this call we may need to terminate the zstream ownership.
4175 */
4176 png_read_IDAT_data(png_ptr, NULL, 0);
4177 png_ptr->zstream.next_out = NULL; /* safety */
4178
4179 /* Now clear everything out for safety; the following may not have been
4180 * done.
4181 */
4182 if ((png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0)
4183 {
4184 png_ptr->mode |= PNG_AFTER_IDAT;
4185 png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
4186 }
4187 }
4188
4189 /* If the zstream has not been released do it now *and* terminate the reading
4190 * of the final IDAT chunk.
4191 */
4192 if (png_ptr->zowner == png_IDAT)
4193 {
4194 /* Always do this; the pointers otherwise point into the read buffer. */
4195 png_ptr->zstream.next_in = NULL;
4196 png_ptr->zstream.avail_in = 0;
4197
4198 /* Now we no longer own the zstream. */
4199 png_ptr->zowner = 0;
4200
4201 /* The slightly weird semantics of the sequential IDAT reading is that we
4202 * are always in or at the end of an IDAT chunk, so we always need to do a
4203 * crc_finish here. If idat_size is non-zero we also need to read the
4204 * spurious bytes at the end of the chunk now.
4205 */
4206 (void)png_crc_finish(png_ptr, png_ptr->idat_size);
4207 }
4208 }
4209
4210 void /* PRIVATE */
4211 png_read_finish_row(png_structrp png_ptr)
4212 {
4213 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
4214
4215 /* Start of interlace block */
4216 static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
4217
4218 /* Offset to next interlace block */
4219 static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
4220
4221 /* Start of interlace block in the y direction */
4222 static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
4223
4224 /* Offset to next interlace block in the y direction */
4225 static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
4226
4227 png_debug(1, "in png_read_finish_row");
4228 png_ptr->row_number++;
4229 if (png_ptr->row_number < png_ptr->num_rows)
4230 return;
4231
4232 if (png_ptr->interlaced != 0)
4233 {
4234 png_ptr->row_number = 0;
4235
4236 /* TO DO: don't do this if prev_row isn't needed (requires
4237 * read-ahead of the next row's filter byte.
4238 */
4239 memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
4240
4241 do
4242 {
4243 png_ptr->pass++;
4244
4245 if (png_ptr->pass >= 7)
4246 break;
4247
4248 png_ptr->iwidth = (png_ptr->width +
4249 png_pass_inc[png_ptr->pass] - 1 -
4250 png_pass_start[png_ptr->pass]) /
4251 png_pass_inc[png_ptr->pass];
4252
4253 if ((png_ptr->transformations & PNG_INTERLACE) == 0)
4254 {
4255 png_ptr->num_rows = (png_ptr->height +
4256 png_pass_yinc[png_ptr->pass] - 1 -
4257 png_pass_ystart[png_ptr->pass]) /
4258 png_pass_yinc[png_ptr->pass];
4259 }
4260
4261 else /* if (png_ptr->transformations & PNG_INTERLACE) */
4262 break; /* libpng deinterlacing sees every row */
4263
4264 } while (png_ptr->num_rows == 0 || png_ptr->iwidth == 0);
4265
4266 if (png_ptr->pass < 7)
4267 return;
4268 }
4269
4270 /* Here after at the end of the last row of the last pass. */
4271 png_read_finish_IDAT(png_ptr);
4272 }
4273 #endif /* SEQUENTIAL_READ */
4274
4275 void /* PRIVATE */
4276 png_read_start_row(png_structrp png_ptr)
4277 {
4278 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
4279
4280 /* Start of interlace block */
4281 static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
4282
4283 /* Offset to next interlace block */
4284 static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
4285
4286 /* Start of interlace block in the y direction */
4287 static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
4288
4289 /* Offset to next interlace block in the y direction */
4290 static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
4291
4292 unsigned int max_pixel_depth;
4293 png_size_t row_bytes;
4294
4295 png_debug(1, "in png_read_start_row");
4296
4297 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
4298 png_init_read_transformations(png_ptr);
4299 #endif
4300 if (png_ptr->interlaced != 0)
4301 {
4302 if ((png_ptr->transformations & PNG_INTERLACE) == 0)
4303 png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 -
4304 png_pass_ystart[0]) / png_pass_yinc[0];
4305
4306 else
4307 png_ptr->num_rows = png_ptr->height;
4308
4309 png_ptr->iwidth = (png_ptr->width +
4310 png_pass_inc[png_ptr->pass] - 1 -
4311 png_pass_start[png_ptr->pass]) /
4312 png_pass_inc[png_ptr->pass];
4313 }
4314
4315 else
4316 {
4317 png_ptr->num_rows = png_ptr->height;
4318 png_ptr->iwidth = png_ptr->width;
4319 }
4320
4321 max_pixel_depth = (unsigned int)png_ptr->pixel_depth;
4322
4323 /* WARNING: * png_read_transform_info (pngrtran.c) performs a simpler set of
4324 * calculations to calculate the final pixel depth, then
4325 * png_do_read_transforms actually does the transforms. This means that the
4326 * code which effectively calculates this value is actually repeated in three
4327 * separate places. They must all match. Innocent changes to the order of
4328 * transformations can and will break libpng in a way that causes memory
4329 * overwrites.
4330 *
4331 * TODO: fix this.
4332 */
4333 #ifdef PNG_READ_PACK_SUPPORTED
4334 if ((png_ptr->transformations & PNG_PACK) != 0 && png_ptr->bit_depth < 8)
4335 max_pixel_depth = 8;
4336 #endif
4337
4338 #ifdef PNG_READ_EXPAND_SUPPORTED
4339 if ((png_ptr->transformations & PNG_EXPAND) != 0)
4340 {
4341 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
4342 {
4343 if (png_ptr->num_trans != 0)
4344 max_pixel_depth = 32;
4345
4346 else
4347 max_pixel_depth = 24;
4348 }
4349
4350 else if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
4351 {
4352 if (max_pixel_depth < 8)
4353 max_pixel_depth = 8;
4354
4355 if (png_ptr->num_trans != 0)
4356 max_pixel_depth *= 2;
4357 }
4358
4359 else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
4360 {
4361 if (png_ptr->num_trans != 0)
4362 {
4363 max_pixel_depth *= 4;
4364 max_pixel_depth /= 3;
4365 }
4366 }
4367 }
4368 #endif
4369
4370 #ifdef PNG_READ_EXPAND_16_SUPPORTED
4371 if ((png_ptr->transformations & PNG_EXPAND_16) != 0)
4372 {
4373 # ifdef PNG_READ_EXPAND_SUPPORTED
4374 /* In fact it is an error if it isn't supported, but checking is
4375 * the safe way.
4376 */
4377 if ((png_ptr->transformations & PNG_EXPAND) != 0)
4378 {
4379 if (png_ptr->bit_depth < 16)
4380 max_pixel_depth *= 2;
4381 }
4382 else
4383 # endif
4384 png_ptr->transformations &= ~PNG_EXPAND_16;
4385 }
4386 #endif
4387
4388 #ifdef PNG_READ_FILLER_SUPPORTED
4389 if ((png_ptr->transformations & (PNG_FILLER)) != 0)
4390 {
4391 if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
4392 {
4393 if (max_pixel_depth <= 8)
4394 max_pixel_depth = 16;
4395
4396 else
4397 max_pixel_depth = 32;
4398 }
4399
4400 else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB ||
4401 png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
4402 {
4403 if (max_pixel_depth <= 32)
4404 max_pixel_depth = 32;
4405
4406 else
4407 max_pixel_depth = 64;
4408 }
4409 }
4410 #endif
4411
4412 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
4413 if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0)
4414 {
4415 if (
4416 #ifdef PNG_READ_EXPAND_SUPPORTED
4417 (png_ptr->num_trans != 0 &&
4418 (png_ptr->transformations & PNG_EXPAND) != 0) ||
4419 #endif
4420 #ifdef PNG_READ_FILLER_SUPPORTED
4421 (png_ptr->transformations & (PNG_FILLER)) != 0 ||
4422 #endif
4423 png_ptr->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
4424 {
4425 if (max_pixel_depth <= 16)
4426 max_pixel_depth = 32;
4427
4428 else
4429 max_pixel_depth = 64;
4430 }
4431
4432 else
4433 {
4434 if (max_pixel_depth <= 8)
4435 {
4436 if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
4437 max_pixel_depth = 32;
4438
4439 else
4440 max_pixel_depth = 24;
4441 }
4442
4443 else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
4444 max_pixel_depth = 64;
4445
4446 else
4447 max_pixel_depth = 48;
4448 }
4449 }
4450 #endif
4451
4452 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) && \
4453 defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
4454 if ((png_ptr->transformations & PNG_USER_TRANSFORM) != 0)
4455 {
4456 unsigned int user_pixel_depth = png_ptr->user_transform_depth *
4457 png_ptr->user_transform_channels;
4458
4459 if (user_pixel_depth > max_pixel_depth)
4460 max_pixel_depth = user_pixel_depth;
4461 }
4462 #endif
4463
4464 /* This value is stored in png_struct and double checked in the row read
4465 * code.
4466 */
4467 png_ptr->maximum_pixel_depth = (png_byte)max_pixel_depth;
4468 png_ptr->transformed_pixel_depth = 0; /* calculated on demand */
4469
4470 /* Align the width on the next larger 8 pixels. Mainly used
4471 * for interlacing
4472 */
4473 row_bytes = ((png_ptr->width + 7) & ~((png_uint_32)7));
4474 /* Calculate the maximum bytes needed, adding a byte and a pixel
4475 * for safety's sake
4476 */
4477 row_bytes = PNG_ROWBYTES(max_pixel_depth, row_bytes) +
4478 1 + ((max_pixel_depth + 7) >> 3U);
4479
4480 #ifdef PNG_MAX_MALLOC_64K
4481 if (row_bytes > (png_uint_32)65536L)
4482 png_error(png_ptr, "This image requires a row greater than 64KB");
4483 #endif
4484
4485 if (row_bytes + 48 > png_ptr->old_big_row_buf_size)
4486 {
4487 png_free(png_ptr, png_ptr->big_row_buf);
4488 png_free(png_ptr, png_ptr->big_prev_row);
4489
4490 if (png_ptr->interlaced != 0)
4491 png_ptr->big_row_buf = (png_bytep)png_calloc(png_ptr,
4492 row_bytes + 48);
4493
4494 else
4495 png_ptr->big_row_buf = (png_bytep)png_malloc(png_ptr, row_bytes + 48);
4496
4497 png_ptr->big_prev_row = (png_bytep)png_malloc(png_ptr, row_bytes + 48);
4498
4499 #ifdef PNG_ALIGNED_MEMORY_SUPPORTED
4500 /* Use 16-byte aligned memory for row_buf with at least 16 bytes
4501 * of padding before and after row_buf; treat prev_row similarly.
4502 * NOTE: the alignment is to the start of the pixels, one beyond the start
4503 * of the buffer, because of the filter byte. Prior to libpng 1.5.6 this
4504 * was incorrect; the filter byte was aligned, which had the exact
4505 * opposite effect of that intended.
4506 */
4507 {
4508 png_bytep temp = png_ptr->big_row_buf + 32;
4509 int extra = (int)((temp - (png_bytep)0) & 0x0f);
4510 png_ptr->row_buf = temp - extra - 1/*filter byte*/;
4511
4512 temp = png_ptr->big_prev_row + 32;
4513 extra = (int)((temp - (png_bytep)0) & 0x0f);
4514 png_ptr->prev_row = temp - extra - 1/*filter byte*/;
4515 }
4516
4517 #else
4518 /* Use 31 bytes of padding before and 17 bytes after row_buf. */
4519 png_ptr->row_buf = png_ptr->big_row_buf + 31;
4520 png_ptr->prev_row = png_ptr->big_prev_row + 31;
4521 #endif
4522 png_ptr->old_big_row_buf_size = row_bytes + 48;
4523 }
4524
4525 #ifdef PNG_MAX_MALLOC_64K
4526 if (png_ptr->rowbytes > 65535)
4527 png_error(png_ptr, "This image requires a row greater than 64KB");
4528
4529 #endif
4530 if (png_ptr->rowbytes > (PNG_SIZE_MAX - 1))
4531 png_error(png_ptr, "Row has too many bytes to allocate in memory");
4532
4533 memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
4534
4535 png_debug1(3, "width = %u,", png_ptr->width);
4536 png_debug1(3, "height = %u,", png_ptr->height);
4537 png_debug1(3, "iwidth = %u,", png_ptr->iwidth);
4538 png_debug1(3, "num_rows = %u,", png_ptr->num_rows);
4539 png_debug1(3, "rowbytes = %lu,", (unsigned long)png_ptr->rowbytes);
4540 png_debug1(3, "irowbytes = %lu",
4541 (unsigned long)PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->iwidth) + 1);
4542
4543 /* The sequential reader needs a buffer for IDAT, but the progressive reader
4544 * does not, so free the read buffer now regardless; the sequential reader
4545 * reallocates it on demand.
4546 */
4547 if (png_ptr->read_buffer != NULL)
4548 {
4549 png_bytep buffer = png_ptr->read_buffer;
4550
4551 png_ptr->read_buffer_size = 0;
4552 png_ptr->read_buffer = NULL;
4553 png_free(png_ptr, buffer);
4554 }
4555
4556 /* Finally claim the zstream for the inflate of the IDAT data, use the bits
4557 * value from the stream (note that this will result in a fatal error if the
4558 * IDAT stream has a bogus deflate header window_bits value, but this should
4559 * not be happening any longer!)
4560 */
4561 if (png_inflate_claim(png_ptr, png_IDAT) != Z_OK)
4562 png_error(png_ptr, png_ptr->zstream.msg);
4563
4564 png_ptr->flags |= PNG_FLAG_ROW_INIT;
4565 }
4566 #endif /* READ */