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 1.6.33 [September 28, 2017]
33 * Copyright (c) 1998-2002,2004,2006-2017 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 /* Check for too-large chunk length */
213 png_check_chunk_length(png_ptr, length);
214
215 #ifdef PNG_IO_STATE_SUPPORTED
216 png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_DATA;
217 #endif
218
219 return length;
220 }
221
222 /* Read data, and (optionally) run it through the CRC. */
223 void /* PRIVATE */
224 png_crc_read(png_structrp png_ptr, png_bytep buf, png_uint_32 length)
225 {
226 if (png_ptr == NULL)
227 return;
228
229 png_read_data(png_ptr, buf, length);
230 png_calculate_crc(png_ptr, buf, length);
231 }
232
233 /* Optionally skip data and then check the CRC. Depending on whether we
234 * are reading an ancillary or critical chunk, and how the program has set
235 * things up, we may calculate the CRC on the data and print a message.
236 * Returns '1' if there was a CRC error, '0' otherwise.
237 */
238 int /* PRIVATE */
239 png_crc_finish(png_structrp png_ptr, png_uint_32 skip)
240 {
241 /* The size of the local buffer for inflate is a good guess as to a
242 * reasonable size to use for buffering reads from the application.
243 */
244 while (skip > 0)
245 {
246 png_uint_32 len;
247 png_byte tmpbuf[PNG_INFLATE_BUF_SIZE];
248
249 len = (sizeof tmpbuf);
250 if (len > skip)
251 len = skip;
252 skip -= len;
253
254 png_crc_read(png_ptr, tmpbuf, len);
255 }
256
257 if (png_crc_error(png_ptr) != 0)
258 {
259 if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name) != 0 ?
260 (png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) == 0 :
261 (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_USE) != 0)
262 {
263 png_chunk_warning(png_ptr, "CRC error");
264 }
265
266 else
267 png_chunk_error(png_ptr, "CRC error");
268
269 return (1);
270 }
271
272 return (0);
273 }
274
275 /* Compare the CRC stored in the PNG file with that calculated by libpng from
276 * the data it has read thus far.
277 */
278 int /* PRIVATE */
279 png_crc_error(png_structrp png_ptr)
280 {
281 png_byte crc_bytes[4];
282 png_uint_32 crc;
283 int need_crc = 1;
284
285 if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name) != 0)
286 {
287 if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) ==
288 (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN))
289 need_crc = 0;
290 }
291
292 else /* critical */
293 {
294 if ((png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE) != 0)
295 need_crc = 0;
296 }
297
298 #ifdef PNG_IO_STATE_SUPPORTED
299 png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_CRC;
300 #endif
301
302 /* The chunk CRC must be serialized in a single I/O call. */
303 png_read_data(png_ptr, crc_bytes, 4);
304
305 if (need_crc != 0)
306 {
307 crc = png_get_uint_32(crc_bytes);
308 return ((int)(crc != png_ptr->crc));
309 }
310
311 else
312 return (0);
313 }
314
315 #if defined(PNG_READ_iCCP_SUPPORTED) || defined(PNG_READ_iTXt_SUPPORTED) ||\
316 defined(PNG_READ_pCAL_SUPPORTED) || defined(PNG_READ_sCAL_SUPPORTED) ||\
317 defined(PNG_READ_sPLT_SUPPORTED) || defined(PNG_READ_tEXt_SUPPORTED) ||\
318 defined(PNG_READ_zTXt_SUPPORTED) || defined(PNG_SEQUENTIAL_READ_SUPPORTED)
319 /* Manage the read buffer; this simply reallocates the buffer if it is not small
320 * enough (or if it is not allocated). The routine returns a pointer to the
321 * buffer; if an error occurs and 'warn' is set the routine returns NULL, else
322 * it will call png_error (via png_malloc) on failure. (warn == 2 means
323 * 'silent').
324 */
325 static png_bytep
326 png_read_buffer(png_structrp png_ptr, png_alloc_size_t new_size, int warn)
327 {
328 png_bytep buffer = png_ptr->read_buffer;
329
330 if (buffer != NULL && new_size > png_ptr->read_buffer_size)
331 {
332 png_ptr->read_buffer = NULL;
333 png_ptr->read_buffer = NULL;
334 png_ptr->read_buffer_size = 0;
335 png_free(png_ptr, buffer);
336 buffer = NULL;
337 }
338
339 if (buffer == NULL)
340 {
341 buffer = png_voidcast(png_bytep, png_malloc_base(png_ptr, new_size));
342
343 if (buffer != NULL)
344 {
345 memset(buffer, 0, new_size); /* just in case */
346 png_ptr->read_buffer = buffer;
347 png_ptr->read_buffer_size = new_size;
348 }
349
350 else if (warn < 2) /* else silent */
351 {
352 if (warn != 0)
353 png_chunk_warning(png_ptr, "insufficient memory to read chunk");
354
355 else
356 png_chunk_error(png_ptr, "insufficient memory to read chunk");
357 }
358 }
359
360 return buffer;
361 }
362 #endif /* READ_iCCP|iTXt|pCAL|sCAL|sPLT|tEXt|zTXt|SEQUENTIAL_READ */
363
364 /* png_inflate_claim: claim the zstream for some nefarious purpose that involves
365 * decompression. Returns Z_OK on success, else a zlib error code. It checks
366 * the owner but, in final release builds, just issues a warning if some other
367 * chunk apparently owns the stream. Prior to release it does a png_error.
368 */
369 static int
370 png_inflate_claim(png_structrp png_ptr, png_uint_32 owner)
371 {
372 if (png_ptr->zowner != 0)
373 {
374 char msg[64];
375
376 PNG_STRING_FROM_CHUNK(msg, png_ptr->zowner);
377 /* So the message that results is "<chunk> using zstream"; this is an
378 * internal error, but is very useful for debugging. i18n requirements
379 * are minimal.
380 */
381 (void)png_safecat(msg, (sizeof msg), 4, " using zstream");
382 #if PNG_RELEASE_BUILD
383 png_chunk_warning(png_ptr, msg);
384 png_ptr->zowner = 0;
385 #else
386 png_chunk_error(png_ptr, msg);
387 #endif
388 }
389
390 /* Implementation note: unlike 'png_deflate_claim' this internal function
391 * does not take the size of the data as an argument. Some efficiency could
392 * be gained by using this when it is known *if* the zlib stream itself does
393 * not record the number; however, this is an illusion: the original writer
394 * of the PNG may have selected a lower window size, and we really must
395 * follow that because, for systems with with limited capabilities, we
396 * would otherwise reject the application's attempts to use a smaller window
397 * size (zlib doesn't have an interface to say "this or lower"!).
398 *
399 * inflateReset2 was added to zlib 1.2.4; before this the window could not be
400 * reset, therefore it is necessary to always allocate the maximum window
401 * size with earlier zlibs just in case later compressed chunks need it.
402 */
403 {
404 int ret; /* zlib return code */
405 #if ZLIB_VERNUM >= 0x1240
406 int window_bits = 0;
407
408 # if defined(PNG_SET_OPTION_SUPPORTED) && defined(PNG_MAXIMUM_INFLATE_WINDOW)
409 if (((png_ptr->options >> PNG_MAXIMUM_INFLATE_WINDOW) & 3) ==
410 PNG_OPTION_ON)
411 {
412 window_bits = 15;
413 png_ptr->zstream_start = 0; /* fixed window size */
414 }
415
416 else
417 {
418 png_ptr->zstream_start = 1;
419 }
420 # endif
421
422 #endif /* ZLIB_VERNUM >= 0x1240 */
423
424 /* Set this for safety, just in case the previous owner left pointers to
425 * memory allocations.
426 */
427 png_ptr->zstream.next_in = NULL;
428 png_ptr->zstream.avail_in = 0;
429 png_ptr->zstream.next_out = NULL;
430 png_ptr->zstream.avail_out = 0;
431
432 if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0)
433 {
434 #if ZLIB_VERNUM >= 0x1240
435 ret = inflateReset2(&png_ptr->zstream, window_bits);
436 #else
437 ret = inflateReset(&png_ptr->zstream);
438 #endif
439 }
440
441 else
442 {
443 #if ZLIB_VERNUM >= 0x1240
444 ret = inflateInit2(&png_ptr->zstream, window_bits);
445 #else
446 ret = inflateInit(&png_ptr->zstream);
447 #endif
448
449 if (ret == Z_OK)
450 png_ptr->flags |= PNG_FLAG_ZSTREAM_INITIALIZED;
451 }
452
453 #if ZLIB_VERNUM >= 0x1290 && \
454 defined(PNG_SET_OPTION_SUPPORTED) && defined(PNG_IGNORE_ADLER32)
455 if (((png_ptr->options >> PNG_IGNORE_ADLER32) & 3) == PNG_OPTION_ON)
456 /* Turn off validation of the ADLER32 checksum in IDAT chunks */
457 ret = inflateValidate(&png_ptr->zstream, 0);
458 #endif
459
460 if (ret == Z_OK)
461 png_ptr->zowner = owner;
462
463 else
464 png_zstream_error(png_ptr, ret);
465
466 return ret;
467 }
468
469 #ifdef window_bits
470 # undef window_bits
471 #endif
472 }
473
474 #if ZLIB_VERNUM >= 0x1240
475 /* Handle the start of the inflate stream if we called inflateInit2(strm,0);
476 * in this case some zlib versions skip validation of the CINFO field and, in
477 * certain circumstances, libpng may end up displaying an invalid image, in
478 * contrast to implementations that call zlib in the normal way (e.g. libpng
479 * 1.5).
480 */
481 int /* PRIVATE */
482 png_zlib_inflate(png_structrp png_ptr, int flush)
483 {
484 if (png_ptr->zstream_start && png_ptr->zstream.avail_in > 0)
485 {
486 if ((*png_ptr->zstream.next_in >> 4) > 7)
487 {
488 png_ptr->zstream.msg = "invalid window size (libpng)";
489 return Z_DATA_ERROR;
490 }
491
492 png_ptr->zstream_start = 0;
493 }
494
495 return inflate(&png_ptr->zstream, flush);
496 }
497 #endif /* Zlib >= 1.2.4 */
498
499 #ifdef PNG_READ_COMPRESSED_TEXT_SUPPORTED
500 #if defined(PNG_READ_zTXt_SUPPORTED) || defined (PNG_READ_iTXt_SUPPORTED)
501 /* png_inflate now returns zlib error codes including Z_OK and Z_STREAM_END to
502 * allow the caller to do multiple calls if required. If the 'finish' flag is
503 * set Z_FINISH will be passed to the final inflate() call and Z_STREAM_END must
504 * be returned or there has been a problem, otherwise Z_SYNC_FLUSH is used and
505 * Z_OK or Z_STREAM_END will be returned on success.
506 *
507 * The input and output sizes are updated to the actual amounts of data consumed
508 * or written, not the amount available (as in a z_stream). The data pointers
509 * are not changed, so the next input is (data+input_size) and the next
510 * available output is (output+output_size).
511 */
512 static int
513 png_inflate(png_structrp png_ptr, png_uint_32 owner, int finish,
514 /* INPUT: */ png_const_bytep input, png_uint_32p input_size_ptr,
515 /* OUTPUT: */ png_bytep output, png_alloc_size_t *output_size_ptr)
516 {
517 if (png_ptr->zowner == owner) /* Else not claimed */
518 {
519 int ret;
520 png_alloc_size_t avail_out = *output_size_ptr;
521 png_uint_32 avail_in = *input_size_ptr;
522
523 /* zlib can't necessarily handle more than 65535 bytes at once (i.e. it
524 * can't even necessarily handle 65536 bytes) because the type uInt is
525 * "16 bits or more". Consequently it is necessary to chunk the input to
526 * zlib. This code uses ZLIB_IO_MAX, from pngpriv.h, as the maximum (the
527 * maximum value that can be stored in a uInt.) It is possible to set
528 * ZLIB_IO_MAX to a lower value in pngpriv.h and this may sometimes have
529 * a performance advantage, because it reduces the amount of data accessed
530 * at each step and that may give the OS more time to page it in.
531 */
532 png_ptr->zstream.next_in = PNGZ_INPUT_CAST(input);
533 /* avail_in and avail_out are set below from 'size' */
534 png_ptr->zstream.avail_in = 0;
535 png_ptr->zstream.avail_out = 0;
536
537 /* Read directly into the output if it is available (this is set to
538 * a local buffer below if output is NULL).
539 */
540 if (output != NULL)
541 png_ptr->zstream.next_out = output;
542
543 do
544 {
545 uInt avail;
546 Byte local_buffer[PNG_INFLATE_BUF_SIZE];
547
548 /* zlib INPUT BUFFER */
549 /* The setting of 'avail_in' used to be outside the loop; by setting it
550 * inside it is possible to chunk the input to zlib and simply rely on
551 * zlib to advance the 'next_in' pointer. This allows arbitrary
552 * amounts of data to be passed through zlib at the unavoidable cost of
553 * requiring a window save (memcpy of up to 32768 output bytes)
554 * every ZLIB_IO_MAX input bytes.
555 */
556 avail_in += png_ptr->zstream.avail_in; /* not consumed last time */
557
558 avail = ZLIB_IO_MAX;
559
560 if (avail_in < avail)
561 avail = (uInt)avail_in; /* safe: < than ZLIB_IO_MAX */
562
563 avail_in -= avail;
564 png_ptr->zstream.avail_in = avail;
565
566 /* zlib OUTPUT BUFFER */
567 avail_out += png_ptr->zstream.avail_out; /* not written last time */
568
569 avail = ZLIB_IO_MAX; /* maximum zlib can process */
570
571 if (output == NULL)
572 {
573 /* Reset the output buffer each time round if output is NULL and
574 * make available the full buffer, up to 'remaining_space'
575 */
576 png_ptr->zstream.next_out = local_buffer;
577 if ((sizeof local_buffer) < avail)
578 avail = (sizeof local_buffer);
579 }
580
581 if (avail_out < avail)
582 avail = (uInt)avail_out; /* safe: < ZLIB_IO_MAX */
583
584 png_ptr->zstream.avail_out = avail;
585 avail_out -= avail;
586
587 /* zlib inflate call */
588 /* In fact 'avail_out' may be 0 at this point, that happens at the end
589 * of the read when the final LZ end code was not passed at the end of
590 * the previous chunk of input data. Tell zlib if we have reached the
591 * end of the output buffer.
592 */
593 ret = PNG_INFLATE(png_ptr, avail_out > 0 ? Z_NO_FLUSH :
594 (finish ? Z_FINISH : Z_SYNC_FLUSH));
595 } while (ret == Z_OK);
596
597 /* For safety kill the local buffer pointer now */
598 if (output == NULL)
599 png_ptr->zstream.next_out = NULL;
600
601 /* Claw back the 'size' and 'remaining_space' byte counts. */
602 avail_in += png_ptr->zstream.avail_in;
603 avail_out += png_ptr->zstream.avail_out;
604
605 /* Update the input and output sizes; the updated values are the amount
606 * consumed or written, effectively the inverse of what zlib uses.
607 */
608 if (avail_out > 0)
609 *output_size_ptr -= avail_out;
610
611 if (avail_in > 0)
612 *input_size_ptr -= avail_in;
613
614 /* Ensure png_ptr->zstream.msg is set (even in the success case!) */
615 png_zstream_error(png_ptr, ret);
616 return ret;
617 }
618
619 else
620 {
621 /* This is a bad internal error. The recovery assigns to the zstream msg
622 * pointer, which is not owned by the caller, but this is safe; it's only
623 * used on errors!
624 */
625 png_ptr->zstream.msg = PNGZ_MSG_CAST("zstream unclaimed");
626 return Z_STREAM_ERROR;
627 }
628 }
629
630 /*
631 * Decompress trailing data in a chunk. The assumption is that read_buffer
632 * points at an allocated area holding the contents of a chunk with a
633 * trailing compressed part. What we get back is an allocated area
634 * holding the original prefix part and an uncompressed version of the
635 * trailing part (the malloc area passed in is freed).
636 */
637 static int
638 png_decompress_chunk(png_structrp png_ptr,
639 png_uint_32 chunklength, png_uint_32 prefix_size,
640 png_alloc_size_t *newlength /* must be initialized to the maximum! */,
641 int terminate /*add a '\0' to the end of the uncompressed data*/)
642 {
643 /* TODO: implement different limits for different types of chunk.
644 *
645 * The caller supplies *newlength set to the maximum length of the
646 * uncompressed data, but this routine allocates space for the prefix and
647 * maybe a '\0' terminator too. We have to assume that 'prefix_size' is
648 * limited only by the maximum chunk size.
649 */
650 png_alloc_size_t limit = PNG_SIZE_MAX;
651
652 # ifdef PNG_SET_USER_LIMITS_SUPPORTED
653 if (png_ptr->user_chunk_malloc_max > 0 &&
654 png_ptr->user_chunk_malloc_max < limit)
655 limit = png_ptr->user_chunk_malloc_max;
656 # elif PNG_USER_CHUNK_MALLOC_MAX > 0
657 if (PNG_USER_CHUNK_MALLOC_MAX < limit)
658 limit = PNG_USER_CHUNK_MALLOC_MAX;
659 # endif
660
661 if (limit >= prefix_size + (terminate != 0))
662 {
663 int ret;
664
665 limit -= prefix_size + (terminate != 0);
666
667 if (limit < *newlength)
668 *newlength = limit;
669
670 /* Now try to claim the stream. */
671 ret = png_inflate_claim(png_ptr, png_ptr->chunk_name);
672
673 if (ret == Z_OK)
674 {
675 png_uint_32 lzsize = chunklength - prefix_size;
676
677 ret = png_inflate(png_ptr, png_ptr->chunk_name, 1/*finish*/,
678 /* input: */ png_ptr->read_buffer + prefix_size, &lzsize,
679 /* output: */ NULL, newlength);
680
681 if (ret == Z_STREAM_END)
682 {
683 /* Use 'inflateReset' here, not 'inflateReset2' because this
684 * preserves the previously decided window size (otherwise it would
685 * be necessary to store the previous window size.) In practice
686 * this doesn't matter anyway, because png_inflate will call inflate
687 * with Z_FINISH in almost all cases, so the window will not be
688 * maintained.
689 */
690 if (inflateReset(&png_ptr->zstream) == Z_OK)
691 {
692 /* Because of the limit checks above we know that the new,
693 * expanded, size will fit in a size_t (let alone an
694 * png_alloc_size_t). Use png_malloc_base here to avoid an
695 * extra OOM message.
696 */
697 png_alloc_size_t new_size = *newlength;
698 png_alloc_size_t buffer_size = prefix_size + new_size +
699 (terminate != 0);
700 png_bytep text = png_voidcast(png_bytep, png_malloc_base(png_ptr,
701 buffer_size));
702
703 if (text != NULL)
704 {
705 memset(text, 0, buffer_size);
706
707 ret = png_inflate(png_ptr, png_ptr->chunk_name, 1/*finish*/,
708 png_ptr->read_buffer + prefix_size, &lzsize,
709 text + prefix_size, newlength);
710
711 if (ret == Z_STREAM_END)
712 {
713 if (new_size == *newlength)
714 {
715 if (terminate != 0)
716 text[prefix_size + *newlength] = 0;
717
718 if (prefix_size > 0)
719 memcpy(text, png_ptr->read_buffer, prefix_size);
720
721 {
722 png_bytep old_ptr = png_ptr->read_buffer;
723
724 png_ptr->read_buffer = text;
725 png_ptr->read_buffer_size = buffer_size;
726 text = old_ptr; /* freed below */
727 }
728 }
729
730 else
731 {
732 /* The size changed on the second read, there can be no
733 * guarantee that anything is correct at this point.
734 * The 'msg' pointer has been set to "unexpected end of
735 * LZ stream", which is fine, but return an error code
736 * that the caller won't accept.
737 */
738 ret = PNG_UNEXPECTED_ZLIB_RETURN;
739 }
740 }
741
742 else if (ret == Z_OK)
743 ret = PNG_UNEXPECTED_ZLIB_RETURN; /* for safety */
744
745 /* Free the text pointer (this is the old read_buffer on
746 * success)
747 */
748 png_free(png_ptr, text);
749
750 /* This really is very benign, but it's still an error because
751 * the extra space may otherwise be used as a Trojan Horse.
752 */
753 if (ret == Z_STREAM_END &&
754 chunklength - prefix_size != lzsize)
755 png_chunk_benign_error(png_ptr, "extra compressed data");
756 }
757
758 else
759 {
760 /* Out of memory allocating the buffer */
761 ret = Z_MEM_ERROR;
762 png_zstream_error(png_ptr, Z_MEM_ERROR);
763 }
764 }
765
766 else
767 {
768 /* inflateReset failed, store the error message */
769 png_zstream_error(png_ptr, ret);
770 ret = PNG_UNEXPECTED_ZLIB_RETURN;
771 }
772 }
773
774 else if (ret == Z_OK)
775 ret = PNG_UNEXPECTED_ZLIB_RETURN;
776
777 /* Release the claimed stream */
778 png_ptr->zowner = 0;
779 }
780
781 else /* the claim failed */ if (ret == Z_STREAM_END) /* impossible! */
782 ret = PNG_UNEXPECTED_ZLIB_RETURN;
783
784 return ret;
785 }
786
787 else
788 {
789 /* Application/configuration limits exceeded */
790 png_zstream_error(png_ptr, Z_MEM_ERROR);
791 return Z_MEM_ERROR;
792 }
793 }
794 #endif /* READ_zTXt || READ_iTXt */
795 #endif /* READ_COMPRESSED_TEXT */
796
797 #ifdef PNG_READ_iCCP_SUPPORTED
798 /* Perform a partial read and decompress, producing 'avail_out' bytes and
799 * reading from the current chunk as required.
800 */
801 static int
802 png_inflate_read(png_structrp png_ptr, png_bytep read_buffer, uInt read_size,
803 png_uint_32p chunk_bytes, png_bytep next_out, png_alloc_size_t *out_size,
804 int finish)
805 {
806 if (png_ptr->zowner == png_ptr->chunk_name)
807 {
808 int ret;
809
810 /* next_in and avail_in must have been initialized by the caller. */
811 png_ptr->zstream.next_out = next_out;
812 png_ptr->zstream.avail_out = 0; /* set in the loop */
813
814 do
815 {
816 if (png_ptr->zstream.avail_in == 0)
817 {
818 if (read_size > *chunk_bytes)
819 read_size = (uInt)*chunk_bytes;
820 *chunk_bytes -= read_size;
821
822 if (read_size > 0)
823 png_crc_read(png_ptr, read_buffer, read_size);
824
825 png_ptr->zstream.next_in = read_buffer;
826 png_ptr->zstream.avail_in = read_size;
827 }
828
829 if (png_ptr->zstream.avail_out == 0)
830 {
831 uInt avail = ZLIB_IO_MAX;
832 if (avail > *out_size)
833 avail = (uInt)*out_size;
834 *out_size -= avail;
835
836 png_ptr->zstream.avail_out = avail;
837 }
838
839 /* Use Z_SYNC_FLUSH when there is no more chunk data to ensure that all
840 * the available output is produced; this allows reading of truncated
841 * streams.
842 */
843 ret = PNG_INFLATE(png_ptr, *chunk_bytes > 0 ?
844 Z_NO_FLUSH : (finish ? Z_FINISH : Z_SYNC_FLUSH));
845 }
846 while (ret == Z_OK && (*out_size > 0 || png_ptr->zstream.avail_out > 0));
847
848 *out_size += png_ptr->zstream.avail_out;
849 png_ptr->zstream.avail_out = 0; /* Should not be required, but is safe */
850
851 /* Ensure the error message pointer is always set: */
852 png_zstream_error(png_ptr, ret);
853 return ret;
854 }
855
856 else
857 {
858 png_ptr->zstream.msg = PNGZ_MSG_CAST("zstream unclaimed");
859 return Z_STREAM_ERROR;
860 }
861 }
862 #endif /* READ_iCCP */
863
864 /* Read and check the IDHR chunk */
865
866 void /* PRIVATE */
867 png_handle_IHDR(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
868 {
869 png_byte buf[13];
870 png_uint_32 width, height;
871 int bit_depth, color_type, compression_type, filter_type;
872 int interlace_type;
873
874 png_debug(1, "in png_handle_IHDR");
875
876 if ((png_ptr->mode & PNG_HAVE_IHDR) != 0)
877 png_chunk_error(png_ptr, "out of place");
878
879 /* Check the length */
880 if (length != 13)
881 png_chunk_error(png_ptr, "invalid");
882
883 png_ptr->mode |= PNG_HAVE_IHDR;
884
885 png_crc_read(png_ptr, buf, 13);
886 png_crc_finish(png_ptr, 0);
887
888 width = png_get_uint_31(png_ptr, buf);
889 height = png_get_uint_31(png_ptr, buf + 4);
890 bit_depth = buf[8];
891 color_type = buf[9];
892 compression_type = buf[10];
893 filter_type = buf[11];
894 interlace_type = buf[12];
895
896 /* Set internal variables */
897 png_ptr->width = width;
898 png_ptr->height = height;
899 png_ptr->bit_depth = (png_byte)bit_depth;
900 png_ptr->interlaced = (png_byte)interlace_type;
901 png_ptr->color_type = (png_byte)color_type;
902 #ifdef PNG_MNG_FEATURES_SUPPORTED
903 png_ptr->filter_type = (png_byte)filter_type;
904 #endif
905 png_ptr->compression_type = (png_byte)compression_type;
906
907 /* Find number of channels */
908 switch (png_ptr->color_type)
909 {
910 default: /* invalid, png_set_IHDR calls png_error */
911 case PNG_COLOR_TYPE_GRAY:
912 case PNG_COLOR_TYPE_PALETTE:
913 png_ptr->channels = 1;
914 break;
915
916 case PNG_COLOR_TYPE_RGB:
917 png_ptr->channels = 3;
918 break;
919
920 case PNG_COLOR_TYPE_GRAY_ALPHA:
921 png_ptr->channels = 2;
922 break;
923
924 case PNG_COLOR_TYPE_RGB_ALPHA:
925 png_ptr->channels = 4;
926 break;
927 }
928
929 /* Set up other useful info */
930 png_ptr->pixel_depth = (png_byte)(png_ptr->bit_depth * png_ptr->channels);
931 png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->width);
932 png_debug1(3, "bit_depth = %d", png_ptr->bit_depth);
933 png_debug1(3, "channels = %d", png_ptr->channels);
934 png_debug1(3, "rowbytes = %lu", (unsigned long)png_ptr->rowbytes);
935 png_set_IHDR(png_ptr, info_ptr, width, height, bit_depth,
936 color_type, interlace_type, compression_type, filter_type);
937 }
938
939 /* Read and check the palette */
940 void /* PRIVATE */
941 png_handle_PLTE(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
942 {
943 png_color palette[PNG_MAX_PALETTE_LENGTH];
944 int max_palette_length, num, i;
945 #ifdef PNG_POINTER_INDEXING_SUPPORTED
946 png_colorp pal_ptr;
947 #endif
948
949 png_debug(1, "in png_handle_PLTE");
950
951 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
952 png_chunk_error(png_ptr, "missing IHDR");
953
954 /* Moved to before the 'after IDAT' check below because otherwise duplicate
955 * PLTE chunks are potentially ignored (the spec says there shall not be more
956 * than one PLTE, the error is not treated as benign, so this check trumps
957 * the requirement that PLTE appears before IDAT.)
958 */
959 else if ((png_ptr->mode & PNG_HAVE_PLTE) != 0)
960 png_chunk_error(png_ptr, "duplicate");
961
962 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
963 {
964 /* This is benign because the non-benign error happened before, when an
965 * IDAT was encountered in a color-mapped image with no PLTE.
966 */
967 png_crc_finish(png_ptr, length);
968 png_chunk_benign_error(png_ptr, "out of place");
969 return;
970 }
971
972 png_ptr->mode |= PNG_HAVE_PLTE;
973
974 if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0)
975 {
976 png_crc_finish(png_ptr, length);
977 png_chunk_benign_error(png_ptr, "ignored in grayscale PNG");
978 return;
979 }
980
981 #ifndef PNG_READ_OPT_PLTE_SUPPORTED
982 if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
983 {
984 png_crc_finish(png_ptr, length);
985 return;
986 }
987 #endif
988
989 if (length > 3*PNG_MAX_PALETTE_LENGTH || length % 3)
990 {
991 png_crc_finish(png_ptr, length);
992
993 if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
994 png_chunk_benign_error(png_ptr, "invalid");
995
996 else
997 png_chunk_error(png_ptr, "invalid");
998
999 return;
1000 }
1001
1002 /* The cast is safe because 'length' is less than 3*PNG_MAX_PALETTE_LENGTH */
1003 num = (int)length / 3;
1004
1005 /* If the palette has 256 or fewer entries but is too large for the bit
1006 * depth, we don't issue an error, to preserve the behavior of previous
1007 * libpng versions. We silently truncate the unused extra palette entries
1008 * here.
1009 */
1010 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1011 max_palette_length = (1 << png_ptr->bit_depth);
1012 else
1013 max_palette_length = PNG_MAX_PALETTE_LENGTH;
1014
1015 if (num > max_palette_length)
1016 num = max_palette_length;
1017
1018 #ifdef PNG_POINTER_INDEXING_SUPPORTED
1019 for (i = 0, pal_ptr = palette; i < num; i++, pal_ptr++)
1020 {
1021 png_byte buf[3];
1022
1023 png_crc_read(png_ptr, buf, 3);
1024 pal_ptr->red = buf[0];
1025 pal_ptr->green = buf[1];
1026 pal_ptr->blue = buf[2];
1027 }
1028 #else
1029 for (i = 0; i < num; i++)
1030 {
1031 png_byte buf[3];
1032
1033 png_crc_read(png_ptr, buf, 3);
1034 /* Don't depend upon png_color being any order */
1035 palette[i].red = buf[0];
1036 palette[i].green = buf[1];
1037 palette[i].blue = buf[2];
1038 }
1039 #endif
1040
1041 /* If we actually need the PLTE chunk (ie for a paletted image), we do
1042 * whatever the normal CRC configuration tells us. However, if we
1043 * have an RGB image, the PLTE can be considered ancillary, so
1044 * we will act as though it is.
1045 */
1046 #ifndef PNG_READ_OPT_PLTE_SUPPORTED
1047 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1048 #endif
1049 {
1050 png_crc_finish(png_ptr, (png_uint_32) (length - (unsigned int)num * 3));
1051 }
1052
1053 #ifndef PNG_READ_OPT_PLTE_SUPPORTED
1054 else if (png_crc_error(png_ptr) != 0) /* Only if we have a CRC error */
1055 {
1056 /* If we don't want to use the data from an ancillary chunk,
1057 * we have two options: an error abort, or a warning and we
1058 * ignore the data in this chunk (which should be OK, since
1059 * it's considered ancillary for a RGB or RGBA image).
1060 *
1061 * IMPLEMENTATION NOTE: this is only here because png_crc_finish uses the
1062 * chunk type to determine whether to check the ancillary or the critical
1063 * flags.
1064 */
1065 if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_USE) == 0)
1066 {
1067 if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) != 0)
1068 return;
1069
1070 else
1071 png_chunk_error(png_ptr, "CRC error");
1072 }
1073
1074 /* Otherwise, we (optionally) emit a warning and use the chunk. */
1075 else if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) == 0)
1076 png_chunk_warning(png_ptr, "CRC error");
1077 }
1078 #endif
1079
1080 /* TODO: png_set_PLTE has the side effect of setting png_ptr->palette to its
1081 * own copy of the palette. This has the side effect that when png_start_row
1082 * is called (this happens after any call to png_read_update_info) the
1083 * info_ptr palette gets changed. This is extremely unexpected and
1084 * confusing.
1085 *
1086 * Fix this by not sharing the palette in this way.
1087 */
1088 png_set_PLTE(png_ptr, info_ptr, palette, num);
1089
1090 /* The three chunks, bKGD, hIST and tRNS *must* appear after PLTE and before
1091 * IDAT. Prior to 1.6.0 this was not checked; instead the code merely
1092 * checked the apparent validity of a tRNS chunk inserted before PLTE on a
1093 * palette PNG. 1.6.0 attempts to rigorously follow the standard and
1094 * therefore does a benign error if the erroneous condition is detected *and*
1095 * cancels the tRNS if the benign error returns. The alternative is to
1096 * amend the standard since it would be rather hypocritical of the standards
1097 * maintainers to ignore it.
1098 */
1099 #ifdef PNG_READ_tRNS_SUPPORTED
1100 if (png_ptr->num_trans > 0 ||
1101 (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS) != 0))
1102 {
1103 /* Cancel this because otherwise it would be used if the transforms
1104 * require it. Don't cancel the 'valid' flag because this would prevent
1105 * detection of duplicate chunks.
1106 */
1107 png_ptr->num_trans = 0;
1108
1109 if (info_ptr != NULL)
1110 info_ptr->num_trans = 0;
1111
1112 png_chunk_benign_error(png_ptr, "tRNS must be after");
1113 }
1114 #endif
1115
1116 #ifdef PNG_READ_hIST_SUPPORTED
1117 if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST) != 0)
1118 png_chunk_benign_error(png_ptr, "hIST must be after");
1119 #endif
1120
1121 #ifdef PNG_READ_bKGD_SUPPORTED
1122 if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD) != 0)
1123 png_chunk_benign_error(png_ptr, "bKGD must be after");
1124 #endif
1125 }
1126
1127 void /* PRIVATE */
1128 png_handle_IEND(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1129 {
1130 png_debug(1, "in png_handle_IEND");
1131
1132 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0 ||
1133 (png_ptr->mode & PNG_HAVE_IDAT) == 0)
1134 png_chunk_error(png_ptr, "out of place");
1135
1136 png_ptr->mode |= (PNG_AFTER_IDAT | PNG_HAVE_IEND);
1137
1138 png_crc_finish(png_ptr, length);
1139
1140 if (length != 0)
1141 png_chunk_benign_error(png_ptr, "invalid");
1142
1143 PNG_UNUSED(info_ptr)
1144 }
1145
1146 #ifdef PNG_READ_gAMA_SUPPORTED
1147 void /* PRIVATE */
1148 png_handle_gAMA(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1149 {
1150 png_fixed_point igamma;
1151 png_byte buf[4];
1152
1153 png_debug(1, "in png_handle_gAMA");
1154
1155 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1156 png_chunk_error(png_ptr, "missing IHDR");
1157
1158 else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
1159 {
1160 png_crc_finish(png_ptr, length);
1161 png_chunk_benign_error(png_ptr, "out of place");
1162 return;
1163 }
1164
1165 if (length != 4)
1166 {
1167 png_crc_finish(png_ptr, length);
1168 png_chunk_benign_error(png_ptr, "invalid");
1169 return;
1170 }
1171
1172 png_crc_read(png_ptr, buf, 4);
1173
1174 if (png_crc_finish(png_ptr, 0) != 0)
1175 return;
1176
1177 igamma = png_get_fixed_point(NULL, buf);
1178
1179 png_colorspace_set_gamma(png_ptr, &png_ptr->colorspace, igamma);
1180 png_colorspace_sync(png_ptr, info_ptr);
1181 }
1182 #endif
1183
1184 #ifdef PNG_READ_sBIT_SUPPORTED
1185 void /* PRIVATE */
1186 png_handle_sBIT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1187 {
1188 unsigned int truelen, i;
1189 png_byte sample_depth;
1190 png_byte buf[4];
1191
1192 png_debug(1, "in png_handle_sBIT");
1193
1194 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1195 png_chunk_error(png_ptr, "missing IHDR");
1196
1197 else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
1198 {
1199 png_crc_finish(png_ptr, length);
1200 png_chunk_benign_error(png_ptr, "out of place");
1201 return;
1202 }
1203
1204 if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sBIT) != 0)
1205 {
1206 png_crc_finish(png_ptr, length);
1207 png_chunk_benign_error(png_ptr, "duplicate");
1208 return;
1209 }
1210
1211 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1212 {
1213 truelen = 3;
1214 sample_depth = 8;
1215 }
1216
1217 else
1218 {
1219 truelen = png_ptr->channels;
1220 sample_depth = png_ptr->bit_depth;
1221 }
1222
1223 if (length != truelen || length > 4)
1224 {
1225 png_chunk_benign_error(png_ptr, "invalid");
1226 png_crc_finish(png_ptr, length);
1227 return;
1228 }
1229
1230 buf[0] = buf[1] = buf[2] = buf[3] = sample_depth;
1231 png_crc_read(png_ptr, buf, truelen);
1232
1233 if (png_crc_finish(png_ptr, 0) != 0)
1234 return;
1235
1236 for (i=0; i<truelen; ++i)
1237 {
1238 if (buf[i] == 0 || buf[i] > sample_depth)
1239 {
1240 png_chunk_benign_error(png_ptr, "invalid");
1241 return;
1242 }
1243 }
1244
1245 if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
1246 {
1247 png_ptr->sig_bit.red = buf[0];
1248 png_ptr->sig_bit.green = buf[1];
1249 png_ptr->sig_bit.blue = buf[2];
1250 png_ptr->sig_bit.alpha = buf[3];
1251 }
1252
1253 else
1254 {
1255 png_ptr->sig_bit.gray = buf[0];
1256 png_ptr->sig_bit.red = buf[0];
1257 png_ptr->sig_bit.green = buf[0];
1258 png_ptr->sig_bit.blue = buf[0];
1259 png_ptr->sig_bit.alpha = buf[1];
1260 }
1261
1262 png_set_sBIT(png_ptr, info_ptr, &(png_ptr->sig_bit));
1263 }
1264 #endif
1265
1266 #ifdef PNG_READ_cHRM_SUPPORTED
1267 void /* PRIVATE */
1268 png_handle_cHRM(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1269 {
1270 png_byte buf[32];
1271 png_xy xy;
1272
1273 png_debug(1, "in png_handle_cHRM");
1274
1275 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1276 png_chunk_error(png_ptr, "missing IHDR");
1277
1278 else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
1279 {
1280 png_crc_finish(png_ptr, length);
1281 png_chunk_benign_error(png_ptr, "out of place");
1282 return;
1283 }
1284
1285 if (length != 32)
1286 {
1287 png_crc_finish(png_ptr, length);
1288 png_chunk_benign_error(png_ptr, "invalid");
1289 return;
1290 }
1291
1292 png_crc_read(png_ptr, buf, 32);
1293
1294 if (png_crc_finish(png_ptr, 0) != 0)
1295 return;
1296
1297 xy.whitex = png_get_fixed_point(NULL, buf);
1298 xy.whitey = png_get_fixed_point(NULL, buf + 4);
1299 xy.redx = png_get_fixed_point(NULL, buf + 8);
1300 xy.redy = png_get_fixed_point(NULL, buf + 12);
1301 xy.greenx = png_get_fixed_point(NULL, buf + 16);
1302 xy.greeny = png_get_fixed_point(NULL, buf + 20);
1303 xy.bluex = png_get_fixed_point(NULL, buf + 24);
1304 xy.bluey = png_get_fixed_point(NULL, buf + 28);
1305
1306 if (xy.whitex == PNG_FIXED_ERROR ||
1307 xy.whitey == PNG_FIXED_ERROR ||
1308 xy.redx == PNG_FIXED_ERROR ||
1309 xy.redy == PNG_FIXED_ERROR ||
1310 xy.greenx == PNG_FIXED_ERROR ||
1311 xy.greeny == PNG_FIXED_ERROR ||
1312 xy.bluex == PNG_FIXED_ERROR ||
1313 xy.bluey == PNG_FIXED_ERROR)
1314 {
1315 png_chunk_benign_error(png_ptr, "invalid values");
1316 return;
1317 }
1318
1319 /* If a colorspace error has already been output skip this chunk */
1320 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0)
1321 return;
1322
1323 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_FROM_cHRM) != 0)
1324 {
1325 png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID;
1326 png_colorspace_sync(png_ptr, info_ptr);
1327 png_chunk_benign_error(png_ptr, "duplicate");
1328 return;
1329 }
1330
1331 png_ptr->colorspace.flags |= PNG_COLORSPACE_FROM_cHRM;
1332 (void)png_colorspace_set_chromaticities(png_ptr, &png_ptr->colorspace, &xy,
1333 1/*prefer cHRM values*/);
1334 png_colorspace_sync(png_ptr, info_ptr);
1335 }
1336 #endif
1337
1338 #ifdef PNG_READ_sRGB_SUPPORTED
1339 void /* PRIVATE */
1340 png_handle_sRGB(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1341 {
1342 png_byte intent;
1343
1344 png_debug(1, "in png_handle_sRGB");
1345
1346 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1347 png_chunk_error(png_ptr, "missing IHDR");
1348
1349 else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
1350 {
1351 png_crc_finish(png_ptr, length);
1352 png_chunk_benign_error(png_ptr, "out of place");
1353 return;
1354 }
1355
1356 if (length != 1)
1357 {
1358 png_crc_finish(png_ptr, length);
1359 png_chunk_benign_error(png_ptr, "invalid");
1360 return;
1361 }
1362
1363 png_crc_read(png_ptr, &intent, 1);
1364
1365 if (png_crc_finish(png_ptr, 0) != 0)
1366 return;
1367
1368 /* If a colorspace error has already been output skip this chunk */
1369 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0)
1370 return;
1371
1372 /* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect
1373 * this.
1374 */
1375 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_INTENT) != 0)
1376 {
1377 png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID;
1378 png_colorspace_sync(png_ptr, info_ptr);
1379 png_chunk_benign_error(png_ptr, "too many profiles");
1380 return;
1381 }
1382
1383 (void)png_colorspace_set_sRGB(png_ptr, &png_ptr->colorspace, intent);
1384 png_colorspace_sync(png_ptr, info_ptr);
1385 }
1386 #endif /* READ_sRGB */
1387
1388 #ifdef PNG_READ_iCCP_SUPPORTED
1389 void /* PRIVATE */
1390 png_handle_iCCP(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1391 /* Note: this does not properly handle profiles that are > 64K under DOS */
1392 {
1393 png_const_charp errmsg = NULL; /* error message output, or no error */
1394 int finished = 0; /* crc checked */
1395
1396 png_debug(1, "in png_handle_iCCP");
1397
1398 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1399 png_chunk_error(png_ptr, "missing IHDR");
1400
1401 else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
1402 {
1403 png_crc_finish(png_ptr, length);
1404 png_chunk_benign_error(png_ptr, "out of place");
1405 return;
1406 }
1407
1408 /* Consistent with all the above colorspace handling an obviously *invalid*
1409 * chunk is just ignored, so does not invalidate the color space. An
1410 * alternative is to set the 'invalid' flags at the start of this routine
1411 * and only clear them in they were not set before and all the tests pass.
1412 */
1413
1414 /* The keyword must be at least one character and there is a
1415 * terminator (0) byte and the compression method byte, and the
1416 * 'zlib' datastream is at least 11 bytes.
1417 */
1418 if (length < 14)
1419 {
1420 png_crc_finish(png_ptr, length);
1421 png_chunk_benign_error(png_ptr, "too short");
1422 return;
1423 }
1424
1425 /* If a colorspace error has already been output skip this chunk */
1426 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0)
1427 {
1428 png_crc_finish(png_ptr, length);
1429 return;
1430 }
1431
1432 /* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect
1433 * this.
1434 */
1435 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_INTENT) == 0)
1436 {
1437 uInt read_length, keyword_length;
1438 char keyword[81];
1439
1440 /* Find the keyword; the keyword plus separator and compression method
1441 * bytes can be at most 81 characters long.
1442 */
1443 read_length = 81; /* maximum */
1444 if (read_length > length)
1445 read_length = (uInt)length;
1446
1447 png_crc_read(png_ptr, (png_bytep)keyword, read_length);
1448 length -= read_length;
1449
1450 /* The minimum 'zlib' stream is assumed to be just the 2 byte header,
1451 * 5 bytes minimum 'deflate' stream, and the 4 byte checksum.
1452 */
1453 if (length < 11)
1454 {
1455 png_crc_finish(png_ptr, length);
1456 png_chunk_benign_error(png_ptr, "too short");
1457 return;
1458 }
1459
1460 keyword_length = 0;
1461 while (keyword_length < 80 && keyword_length < read_length &&
1462 keyword[keyword_length] != 0)
1463 ++keyword_length;
1464
1465 /* TODO: make the keyword checking common */
1466 if (keyword_length >= 1 && keyword_length <= 79)
1467 {
1468 /* We only understand '0' compression - deflate - so if we get a
1469 * different value we can't safely decode the chunk.
1470 */
1471 if (keyword_length+1 < read_length &&
1472 keyword[keyword_length+1] == PNG_COMPRESSION_TYPE_BASE)
1473 {
1474 read_length -= keyword_length+2;
1475
1476 if (png_inflate_claim(png_ptr, png_iCCP) == Z_OK)
1477 {
1478 Byte profile_header[132]={0};
1479 Byte local_buffer[PNG_INFLATE_BUF_SIZE];
1480 png_alloc_size_t size = (sizeof profile_header);
1481
1482 png_ptr->zstream.next_in = (Bytef*)keyword + (keyword_length+2);
1483 png_ptr->zstream.avail_in = read_length;
1484 (void)png_inflate_read(png_ptr, local_buffer,
1485 (sizeof local_buffer), &length, profile_header, &size,
1486 0/*finish: don't, because the output is too small*/);
1487
1488 if (size == 0)
1489 {
1490 /* We have the ICC profile header; do the basic header checks.
1491 */
1492 const png_uint_32 profile_length =
1493 png_get_uint_32(profile_header);
1494
1495 if (png_icc_check_length(png_ptr, &png_ptr->colorspace,
1496 keyword, profile_length) != 0)
1497 {
1498 /* The length is apparently ok, so we can check the 132
1499 * byte header.
1500 */
1501 if (png_icc_check_header(png_ptr, &png_ptr->colorspace,
1502 keyword, profile_length, profile_header,
1503 png_ptr->color_type) != 0)
1504 {
1505 /* Now read the tag table; a variable size buffer is
1506 * needed at this point, allocate one for the whole
1507 * profile. The header check has already validated
1508 * that none of this stuff will overflow.
1509 */
1510 const png_uint_32 tag_count = png_get_uint_32(
1511 profile_header+128);
1512 png_bytep profile = png_read_buffer(png_ptr,
1513 profile_length, 2/*silent*/);
1514
1515 if (profile != NULL)
1516 {
1517 memcpy(profile, profile_header,
1518 (sizeof profile_header));
1519
1520 size = 12 * tag_count;
1521
1522 (void)png_inflate_read(png_ptr, local_buffer,
1523 (sizeof local_buffer), &length,
1524 profile + (sizeof profile_header), &size, 0);
1525
1526 /* Still expect a buffer error because we expect
1527 * there to be some tag data!
1528 */
1529 if (size == 0)
1530 {
1531 if (png_icc_check_tag_table(png_ptr,
1532 &png_ptr->colorspace, keyword, profile_length,
1533 profile) != 0)
1534 {
1535 /* The profile has been validated for basic
1536 * security issues, so read the whole thing in.
1537 */
1538 size = profile_length - (sizeof profile_header)
1539 - 12 * tag_count;
1540
1541 (void)png_inflate_read(png_ptr, local_buffer,
1542 (sizeof local_buffer), &length,
1543 profile + (sizeof profile_header) +
1544 12 * tag_count, &size, 1/*finish*/);
1545
1546 if (length > 0 && !(png_ptr->flags &
1547 PNG_FLAG_BENIGN_ERRORS_WARN))
1548 errmsg = "extra compressed data";
1549
1550 /* But otherwise allow extra data: */
1551 else if (size == 0)
1552 {
1553 if (length > 0)
1554 {
1555 /* This can be handled completely, so
1556 * keep going.
1557 */
1558 png_chunk_warning(png_ptr,
1559 "extra compressed data");
1560 }
1561
1562 png_crc_finish(png_ptr, length);
1563 finished = 1;
1564
1565 # if defined(PNG_sRGB_SUPPORTED) && PNG_sRGB_PROFILE_CHECKS >= 0
1566 /* Check for a match against sRGB */
1567 png_icc_set_sRGB(png_ptr,
1568 &png_ptr->colorspace, profile,
1569 png_ptr->zstream.adler);
1570 # endif
1571
1572 /* Steal the profile for info_ptr. */
1573 if (info_ptr != NULL)
1574 {
1575 png_free_data(png_ptr, info_ptr,
1576 PNG_FREE_ICCP, 0);
1577
1578 info_ptr->iccp_name = png_voidcast(char*,
1579 png_malloc_base(png_ptr,
1580 keyword_length+1));
1581 if (info_ptr->iccp_name != NULL)
1582 {
1583 memcpy(info_ptr->iccp_name, keyword,
1584 keyword_length+1);
1585 info_ptr->iccp_proflen =
1586 profile_length;
1587 info_ptr->iccp_profile = profile;
1588 png_ptr->read_buffer = NULL; /*steal*/
1589 info_ptr->free_me |= PNG_FREE_ICCP;
1590 info_ptr->valid |= PNG_INFO_iCCP;
1591 }
1592
1593 else
1594 {
1595 png_ptr->colorspace.flags |=
1596 PNG_COLORSPACE_INVALID;
1597 errmsg = "out of memory";
1598 }
1599 }
1600
1601 /* else the profile remains in the read
1602 * buffer which gets reused for subsequent
1603 * chunks.
1604 */
1605
1606 if (info_ptr != NULL)
1607 png_colorspace_sync(png_ptr, info_ptr);
1608
1609 if (errmsg == NULL)
1610 {
1611 png_ptr->zowner = 0;
1612 return;
1613 }
1614 }
1615 if (errmsg == NULL)
1616 errmsg = png_ptr->zstream.msg;
1617 }
1618 /* else png_icc_check_tag_table output an error */
1619 }
1620 else /* profile truncated */
1621 errmsg = png_ptr->zstream.msg;
1622 }
1623
1624 else
1625 errmsg = "out of memory";
1626 }
1627
1628 /* else png_icc_check_header output an error */
1629 }
1630
1631 /* else png_icc_check_length output an error */
1632 }
1633
1634 else /* profile truncated */
1635 errmsg = png_ptr->zstream.msg;
1636
1637 /* Release the stream */
1638 png_ptr->zowner = 0;
1639 }
1640
1641 else /* png_inflate_claim failed */
1642 errmsg = png_ptr->zstream.msg;
1643 }
1644
1645 else
1646 errmsg = "bad compression method"; /* or missing */
1647 }
1648
1649 else
1650 errmsg = "bad keyword";
1651 }
1652
1653 else
1654 errmsg = "too many profiles";
1655
1656 /* Failure: the reason is in 'errmsg' */
1657 if (finished == 0)
1658 png_crc_finish(png_ptr, length);
1659
1660 png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID;
1661 png_colorspace_sync(png_ptr, info_ptr);
1662 if (errmsg != NULL) /* else already output */
1663 png_chunk_benign_error(png_ptr, errmsg);
1664 }
1665 #endif /* READ_iCCP */
1666
1667 #ifdef PNG_READ_sPLT_SUPPORTED
1668 void /* PRIVATE */
1669 png_handle_sPLT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1670 /* Note: this does not properly handle chunks that are > 64K under DOS */
1671 {
1672 png_bytep entry_start, buffer;
1673 png_sPLT_t new_palette;
1674 png_sPLT_entryp pp;
1675 png_uint_32 data_length;
1676 int entry_size, i;
1677 png_uint_32 skip = 0;
1678 png_uint_32 dl;
1679 png_size_t max_dl;
1680
1681 png_debug(1, "in png_handle_sPLT");
1682
1683 #ifdef PNG_USER_LIMITS_SUPPORTED
1684 if (png_ptr->user_chunk_cache_max != 0)
1685 {
1686 if (png_ptr->user_chunk_cache_max == 1)
1687 {
1688 png_crc_finish(png_ptr, length);
1689 return;
1690 }
1691
1692 if (--png_ptr->user_chunk_cache_max == 1)
1693 {
1694 png_warning(png_ptr, "No space in chunk cache for sPLT");
1695 png_crc_finish(png_ptr, length);
1696 return;
1697 }
1698 }
1699 #endif
1700
1701 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1702 png_chunk_error(png_ptr, "missing IHDR");
1703
1704 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
1705 {
1706 png_crc_finish(png_ptr, length);
1707 png_chunk_benign_error(png_ptr, "out of place");
1708 return;
1709 }
1710
1711 #ifdef PNG_MAX_MALLOC_64K
1712 if (length > 65535U)
1713 {
1714 png_crc_finish(png_ptr, length);
1715 png_chunk_benign_error(png_ptr, "too large to fit in memory");
1716 return;
1717 }
1718 #endif
1719
1720 buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/);
1721 if (buffer == NULL)
1722 {
1723 png_crc_finish(png_ptr, length);
1724 png_chunk_benign_error(png_ptr, "out of memory");
1725 return;
1726 }
1727
1728
1729 /* WARNING: this may break if size_t is less than 32 bits; it is assumed
1730 * that the PNG_MAX_MALLOC_64K test is enabled in this case, but this is a
1731 * potential breakage point if the types in pngconf.h aren't exactly right.
1732 */
1733 png_crc_read(png_ptr, buffer, length);
1734
1735 if (png_crc_finish(png_ptr, skip) != 0)
1736 return;
1737
1738 buffer[length] = 0;
1739
1740 for (entry_start = buffer; *entry_start; entry_start++)
1741 /* Empty loop to find end of name */ ;
1742
1743 ++entry_start;
1744
1745 /* A sample depth should follow the separator, and we should be on it */
1746 if (length < 2U || entry_start > buffer + (length - 2U))
1747 {
1748 png_warning(png_ptr, "malformed sPLT chunk");
1749 return;
1750 }
1751
1752 new_palette.depth = *entry_start++;
1753 entry_size = (new_palette.depth == 8 ? 6 : 10);
1754 /* This must fit in a png_uint_32 because it is derived from the original
1755 * chunk data length.
1756 */
1757 data_length = length - (png_uint_32)(entry_start - buffer);
1758
1759 /* Integrity-check the data length */
1760 if ((data_length % (unsigned int)entry_size) != 0)
1761 {
1762 png_warning(png_ptr, "sPLT chunk has bad length");
1763 return;
1764 }
1765
1766 dl = (png_uint_32)(data_length / (unsigned int)entry_size);
1767 max_dl = PNG_SIZE_MAX / (sizeof (png_sPLT_entry));
1768
1769 if (dl > max_dl)
1770 {
1771 png_warning(png_ptr, "sPLT chunk too long");
1772 return;
1773 }
1774
1775 new_palette.nentries = (png_int_32)(data_length / (unsigned int)entry_size);
1776
1777 new_palette.entries = (png_sPLT_entryp)png_malloc_warn(png_ptr,
1778 (png_alloc_size_t) new_palette.nentries * (sizeof (png_sPLT_entry)));
1779
1780 if (new_palette.entries == NULL)
1781 {
1782 png_warning(png_ptr, "sPLT chunk requires too much memory");
1783 return;
1784 }
1785
1786 #ifdef PNG_POINTER_INDEXING_SUPPORTED
1787 for (i = 0; i < new_palette.nentries; i++)
1788 {
1789 pp = new_palette.entries + i;
1790
1791 if (new_palette.depth == 8)
1792 {
1793 pp->red = *entry_start++;
1794 pp->green = *entry_start++;
1795 pp->blue = *entry_start++;
1796 pp->alpha = *entry_start++;
1797 }
1798
1799 else
1800 {
1801 pp->red = png_get_uint_16(entry_start); entry_start += 2;
1802 pp->green = png_get_uint_16(entry_start); entry_start += 2;
1803 pp->blue = png_get_uint_16(entry_start); entry_start += 2;
1804 pp->alpha = png_get_uint_16(entry_start); entry_start += 2;
1805 }
1806
1807 pp->frequency = png_get_uint_16(entry_start); entry_start += 2;
1808 }
1809 #else
1810 pp = new_palette.entries;
1811
1812 for (i = 0; i < new_palette.nentries; i++)
1813 {
1814
1815 if (new_palette.depth == 8)
1816 {
1817 pp[i].red = *entry_start++;
1818 pp[i].green = *entry_start++;
1819 pp[i].blue = *entry_start++;
1820 pp[i].alpha = *entry_start++;
1821 }
1822
1823 else
1824 {
1825 pp[i].red = png_get_uint_16(entry_start); entry_start += 2;
1826 pp[i].green = png_get_uint_16(entry_start); entry_start += 2;
1827 pp[i].blue = png_get_uint_16(entry_start); entry_start += 2;
1828 pp[i].alpha = png_get_uint_16(entry_start); entry_start += 2;
1829 }
1830
1831 pp[i].frequency = png_get_uint_16(entry_start); entry_start += 2;
1832 }
1833 #endif
1834
1835 /* Discard all chunk data except the name and stash that */
1836 new_palette.name = (png_charp)buffer;
1837
1838 png_set_sPLT(png_ptr, info_ptr, &new_palette, 1);
1839
1840 png_free(png_ptr, new_palette.entries);
1841 }
1842 #endif /* READ_sPLT */
1843
1844 #ifdef PNG_READ_tRNS_SUPPORTED
1845 void /* PRIVATE */
1846 png_handle_tRNS(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1847 {
1848 png_byte readbuf[PNG_MAX_PALETTE_LENGTH];
1849
1850 png_debug(1, "in png_handle_tRNS");
1851
1852 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1853 png_chunk_error(png_ptr, "missing IHDR");
1854
1855 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
1856 {
1857 png_crc_finish(png_ptr, length);
1858 png_chunk_benign_error(png_ptr, "out of place");
1859 return;
1860 }
1861
1862 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS) != 0)
1863 {
1864 png_crc_finish(png_ptr, length);
1865 png_chunk_benign_error(png_ptr, "duplicate");
1866 return;
1867 }
1868
1869 if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
1870 {
1871 png_byte buf[2];
1872
1873 if (length != 2)
1874 {
1875 png_crc_finish(png_ptr, length);
1876 png_chunk_benign_error(png_ptr, "invalid");
1877 return;
1878 }
1879
1880 png_crc_read(png_ptr, buf, 2);
1881 png_ptr->num_trans = 1;
1882 png_ptr->trans_color.gray = png_get_uint_16(buf);
1883 }
1884
1885 else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
1886 {
1887 png_byte buf[6];
1888
1889 if (length != 6)
1890 {
1891 png_crc_finish(png_ptr, length);
1892 png_chunk_benign_error(png_ptr, "invalid");
1893 return;
1894 }
1895
1896 png_crc_read(png_ptr, buf, length);
1897 png_ptr->num_trans = 1;
1898 png_ptr->trans_color.red = png_get_uint_16(buf);
1899 png_ptr->trans_color.green = png_get_uint_16(buf + 2);
1900 png_ptr->trans_color.blue = png_get_uint_16(buf + 4);
1901 }
1902
1903 else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1904 {
1905 if ((png_ptr->mode & PNG_HAVE_PLTE) == 0)
1906 {
1907 /* TODO: is this actually an error in the ISO spec? */
1908 png_crc_finish(png_ptr, length);
1909 png_chunk_benign_error(png_ptr, "out of place");
1910 return;
1911 }
1912
1913 if (length > (unsigned int) png_ptr->num_palette ||
1914 length > (unsigned int) PNG_MAX_PALETTE_LENGTH ||
1915 length == 0)
1916 {
1917 png_crc_finish(png_ptr, length);
1918 png_chunk_benign_error(png_ptr, "invalid");
1919 return;
1920 }
1921
1922 png_crc_read(png_ptr, readbuf, length);
1923 png_ptr->num_trans = (png_uint_16)length;
1924 }
1925
1926 else
1927 {
1928 png_crc_finish(png_ptr, length);
1929 png_chunk_benign_error(png_ptr, "invalid with alpha channel");
1930 return;
1931 }
1932
1933 if (png_crc_finish(png_ptr, 0) != 0)
1934 {
1935 png_ptr->num_trans = 0;
1936 return;
1937 }
1938
1939 /* TODO: this is a horrible side effect in the palette case because the
1940 * png_struct ends up with a pointer to the tRNS buffer owned by the
1941 * png_info. Fix this.
1942 */
1943 png_set_tRNS(png_ptr, info_ptr, readbuf, png_ptr->num_trans,
1944 &(png_ptr->trans_color));
1945 }
1946 #endif
1947
1948 #ifdef PNG_READ_bKGD_SUPPORTED
1949 void /* PRIVATE */
1950 png_handle_bKGD(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1951 {
1952 unsigned int truelen;
1953 png_byte buf[6];
1954 png_color_16 background;
1955
1956 png_debug(1, "in png_handle_bKGD");
1957
1958 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1959 png_chunk_error(png_ptr, "missing IHDR");
1960
1961 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0 ||
1962 (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
1963 (png_ptr->mode & PNG_HAVE_PLTE) == 0))
1964 {
1965 png_crc_finish(png_ptr, length);
1966 png_chunk_benign_error(png_ptr, "out of place");
1967 return;
1968 }
1969
1970 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD) != 0)
1971 {
1972 png_crc_finish(png_ptr, length);
1973 png_chunk_benign_error(png_ptr, "duplicate");
1974 return;
1975 }
1976
1977 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1978 truelen = 1;
1979
1980 else if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
1981 truelen = 6;
1982
1983 else
1984 truelen = 2;
1985
1986 if (length != truelen)
1987 {
1988 png_crc_finish(png_ptr, length);
1989 png_chunk_benign_error(png_ptr, "invalid");
1990 return;
1991 }
1992
1993 png_crc_read(png_ptr, buf, truelen);
1994
1995 if (png_crc_finish(png_ptr, 0) != 0)
1996 return;
1997
1998 /* We convert the index value into RGB components so that we can allow
1999 * arbitrary RGB values for background when we have transparency, and
2000 * so it is easy to determine the RGB values of the background color
2001 * from the info_ptr struct.
2002 */
2003 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
2004 {
2005 background.index = buf[0];
2006
2007 if (info_ptr != NULL && info_ptr->num_palette != 0)
2008 {
2009 if (buf[0] >= info_ptr->num_palette)
2010 {
2011 png_chunk_benign_error(png_ptr, "invalid index");
2012 return;
2013 }
2014
2015 background.red = (png_uint_16)png_ptr->palette[buf[0]].red;
2016 background.green = (png_uint_16)png_ptr->palette[buf[0]].green;
2017 background.blue = (png_uint_16)png_ptr->palette[buf[0]].blue;
2018 }
2019
2020 else
2021 background.red = background.green = background.blue = 0;
2022
2023 background.gray = 0;
2024 }
2025
2026 else if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0) /* GRAY */
2027 {
2028 background.index = 0;
2029 background.red =
2030 background.green =
2031 background.blue =
2032 background.gray = png_get_uint_16(buf);
2033 }
2034
2035 else
2036 {
2037 background.index = 0;
2038 background.red = png_get_uint_16(buf);
2039 background.green = png_get_uint_16(buf + 2);
2040 background.blue = png_get_uint_16(buf + 4);
2041 background.gray = 0;
2042 }
2043
2044 png_set_bKGD(png_ptr, info_ptr, &background);
2045 }
2046 #endif
2047
2048 #ifdef PNG_READ_eXIf_SUPPORTED
2049 void /* PRIVATE */
2050 png_handle_eXIf(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2051 {
2052 unsigned int i;
2053
2054 png_debug(1, "in png_handle_eXIf");
2055
2056 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2057 png_chunk_error(png_ptr, "missing IHDR");
2058
2059 if (length < 2)
2060 {
2061 png_crc_finish(png_ptr, length);
2062 png_chunk_benign_error(png_ptr, "too short");
2063 return;
2064 }
2065
2066 else if (info_ptr == NULL || (info_ptr->valid & PNG_INFO_eXIf) != 0)
2067 {
2068 png_crc_finish(png_ptr, length);
2069 png_chunk_benign_error(png_ptr, "duplicate");
2070 return;
2071 }
2072
2073 info_ptr->free_me |= PNG_FREE_EXIF;
2074
2075 info_ptr->eXIf_buf = png_voidcast(png_bytep,
2076 png_malloc_warn(png_ptr, length));
2077
2078 if (info_ptr->eXIf_buf == NULL)
2079 {
2080 png_crc_finish(png_ptr, length);
2081 png_chunk_benign_error(png_ptr, "out of memory");
2082 return;
2083 }
2084
2085 for (i = 0; i < length; i++)
2086 {
2087 png_byte buf[1];
2088 png_crc_read(png_ptr, buf, 1);
2089 info_ptr->eXIf_buf[i] = buf[0];
2090 if (i == 1 && buf[0] != 'M' && buf[0] != 'I'
2091 && info_ptr->eXIf_buf[0] != buf[0])
2092 {
2093 png_crc_finish(png_ptr, length);
2094 png_chunk_benign_error(png_ptr, "incorrect byte-order specifier");
2095 png_free(png_ptr, info_ptr->eXIf_buf);
2096 info_ptr->eXIf_buf = NULL;
2097 return;
2098 }
2099 }
2100
2101 if (png_crc_finish(png_ptr, 0) != 0)
2102 return;
2103
2104 png_set_eXIf_1(png_ptr, info_ptr, length, info_ptr->eXIf_buf);
2105
2106 png_free(png_ptr, info_ptr->eXIf_buf);
2107 info_ptr->eXIf_buf = NULL;
2108 }
2109 #endif
2110
2111 #ifdef PNG_READ_hIST_SUPPORTED
2112 void /* PRIVATE */
2113 png_handle_hIST(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2114 {
2115 unsigned int num, i;
2116 png_uint_16 readbuf[PNG_MAX_PALETTE_LENGTH];
2117
2118 png_debug(1, "in png_handle_hIST");
2119
2120 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2121 png_chunk_error(png_ptr, "missing IHDR");
2122
2123 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0 ||
2124 (png_ptr->mode & PNG_HAVE_PLTE) == 0)
2125 {
2126 png_crc_finish(png_ptr, length);
2127 png_chunk_benign_error(png_ptr, "out of place");
2128 return;
2129 }
2130
2131 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST) != 0)
2132 {
2133 png_crc_finish(png_ptr, length);
2134 png_chunk_benign_error(png_ptr, "duplicate");
2135 return;
2136 }
2137
2138 num = length / 2 ;
2139
2140 if (num != (unsigned int) png_ptr->num_palette ||
2141 num > (unsigned int) PNG_MAX_PALETTE_LENGTH)
2142 {
2143 png_crc_finish(png_ptr, length);
2144 png_chunk_benign_error(png_ptr, "invalid");
2145 return;
2146 }
2147
2148 for (i = 0; i < num; i++)
2149 {
2150 png_byte buf[2];
2151
2152 png_crc_read(png_ptr, buf, 2);
2153 readbuf[i] = png_get_uint_16(buf);
2154 }
2155
2156 if (png_crc_finish(png_ptr, 0) != 0)
2157 return;
2158
2159 png_set_hIST(png_ptr, info_ptr, readbuf);
2160 }
2161 #endif
2162
2163 #ifdef PNG_READ_pHYs_SUPPORTED
2164 void /* PRIVATE */
2165 png_handle_pHYs(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2166 {
2167 png_byte buf[9];
2168 png_uint_32 res_x, res_y;
2169 int unit_type;
2170
2171 png_debug(1, "in png_handle_pHYs");
2172
2173 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2174 png_chunk_error(png_ptr, "missing IHDR");
2175
2176 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2177 {
2178 png_crc_finish(png_ptr, length);
2179 png_chunk_benign_error(png_ptr, "out of place");
2180 return;
2181 }
2182
2183 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs) != 0)
2184 {
2185 png_crc_finish(png_ptr, length);
2186 png_chunk_benign_error(png_ptr, "duplicate");
2187 return;
2188 }
2189
2190 if (length != 9)
2191 {
2192 png_crc_finish(png_ptr, length);
2193 png_chunk_benign_error(png_ptr, "invalid");
2194 return;
2195 }
2196
2197 png_crc_read(png_ptr, buf, 9);
2198
2199 if (png_crc_finish(png_ptr, 0) != 0)
2200 return;
2201
2202 res_x = png_get_uint_32(buf);
2203 res_y = png_get_uint_32(buf + 4);
2204 unit_type = buf[8];
2205 png_set_pHYs(png_ptr, info_ptr, res_x, res_y, unit_type);
2206 }
2207 #endif
2208
2209 #ifdef PNG_READ_oFFs_SUPPORTED
2210 void /* PRIVATE */
2211 png_handle_oFFs(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2212 {
2213 png_byte buf[9];
2214 png_int_32 offset_x, offset_y;
2215 int unit_type;
2216
2217 png_debug(1, "in png_handle_oFFs");
2218
2219 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2220 png_chunk_error(png_ptr, "missing IHDR");
2221
2222 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2223 {
2224 png_crc_finish(png_ptr, length);
2225 png_chunk_benign_error(png_ptr, "out of place");
2226 return;
2227 }
2228
2229 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs) != 0)
2230 {
2231 png_crc_finish(png_ptr, length);
2232 png_chunk_benign_error(png_ptr, "duplicate");
2233 return;
2234 }
2235
2236 if (length != 9)
2237 {
2238 png_crc_finish(png_ptr, length);
2239 png_chunk_benign_error(png_ptr, "invalid");
2240 return;
2241 }
2242
2243 png_crc_read(png_ptr, buf, 9);
2244
2245 if (png_crc_finish(png_ptr, 0) != 0)
2246 return;
2247
2248 offset_x = png_get_int_32(buf);
2249 offset_y = png_get_int_32(buf + 4);
2250 unit_type = buf[8];
2251 png_set_oFFs(png_ptr, info_ptr, offset_x, offset_y, unit_type);
2252 }
2253 #endif
2254
2255 #ifdef PNG_READ_pCAL_SUPPORTED
2256 /* Read the pCAL chunk (described in the PNG Extensions document) */
2257 void /* PRIVATE */
2258 png_handle_pCAL(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2259 {
2260 png_int_32 X0, X1;
2261 png_byte type, nparams;
2262 png_bytep buffer, buf, units, endptr;
2263 png_charpp params;
2264 int i;
2265
2266 png_debug(1, "in png_handle_pCAL");
2267
2268 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2269 png_chunk_error(png_ptr, "missing IHDR");
2270
2271 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2272 {
2273 png_crc_finish(png_ptr, length);
2274 png_chunk_benign_error(png_ptr, "out of place");
2275 return;
2276 }
2277
2278 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pCAL) != 0)
2279 {
2280 png_crc_finish(png_ptr, length);
2281 png_chunk_benign_error(png_ptr, "duplicate");
2282 return;
2283 }
2284
2285 png_debug1(2, "Allocating and reading pCAL chunk data (%u bytes)",
2286 length + 1);
2287
2288 buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/);
2289
2290 if (buffer == NULL)
2291 {
2292 png_crc_finish(png_ptr, length);
2293 png_chunk_benign_error(png_ptr, "out of memory");
2294 return;
2295 }
2296
2297 png_crc_read(png_ptr, buffer, length);
2298
2299 if (png_crc_finish(png_ptr, 0) != 0)
2300 return;
2301
2302 buffer[length] = 0; /* Null terminate the last string */
2303
2304 png_debug(3, "Finding end of pCAL purpose string");
2305 for (buf = buffer; *buf; buf++)
2306 /* Empty loop */ ;
2307
2308 endptr = buffer + length;
2309
2310 /* We need to have at least 12 bytes after the purpose string
2311 * in order to get the parameter information.
2312 */
2313 if (endptr - buf <= 12)
2314 {
2315 png_chunk_benign_error(png_ptr, "invalid");
2316 return;
2317 }
2318
2319 png_debug(3, "Reading pCAL X0, X1, type, nparams, and units");
2320 X0 = png_get_int_32((png_bytep)buf+1);
2321 X1 = png_get_int_32((png_bytep)buf+5);
2322 type = buf[9];
2323 nparams = buf[10];
2324 units = buf + 11;
2325
2326 png_debug(3, "Checking pCAL equation type and number of parameters");
2327 /* Check that we have the right number of parameters for known
2328 * equation types.
2329 */
2330 if ((type == PNG_EQUATION_LINEAR && nparams != 2) ||
2331 (type == PNG_EQUATION_BASE_E && nparams != 3) ||
2332 (type == PNG_EQUATION_ARBITRARY && nparams != 3) ||
2333 (type == PNG_EQUATION_HYPERBOLIC && nparams != 4))
2334 {
2335 png_chunk_benign_error(png_ptr, "invalid parameter count");
2336 return;
2337 }
2338
2339 else if (type >= PNG_EQUATION_LAST)
2340 {
2341 png_chunk_benign_error(png_ptr, "unrecognized equation type");
2342 }
2343
2344 for (buf = units; *buf; buf++)
2345 /* Empty loop to move past the units string. */ ;
2346
2347 png_debug(3, "Allocating pCAL parameters array");
2348
2349 params = png_voidcast(png_charpp, png_malloc_warn(png_ptr,
2350 nparams * (sizeof (png_charp))));
2351
2352 if (params == NULL)
2353 {
2354 png_chunk_benign_error(png_ptr, "out of memory");
2355 return;
2356 }
2357
2358 /* Get pointers to the start of each parameter string. */
2359 for (i = 0; i < nparams; i++)
2360 {
2361 buf++; /* Skip the null string terminator from previous parameter. */
2362
2363 png_debug1(3, "Reading pCAL parameter %d", i);
2364
2365 for (params[i] = (png_charp)buf; buf <= endptr && *buf != 0; buf++)
2366 /* Empty loop to move past each parameter string */ ;
2367
2368 /* Make sure we haven't run out of data yet */
2369 if (buf > endptr)
2370 {
2371 png_free(png_ptr, params);
2372 png_chunk_benign_error(png_ptr, "invalid data");
2373 return;
2374 }
2375 }
2376
2377 png_set_pCAL(png_ptr, info_ptr, (png_charp)buffer, X0, X1, type, nparams,
2378 (png_charp)units, params);
2379
2380 png_free(png_ptr, params);
2381 }
2382 #endif
2383
2384 #ifdef PNG_READ_sCAL_SUPPORTED
2385 /* Read the sCAL chunk */
2386 void /* PRIVATE */
2387 png_handle_sCAL(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2388 {
2389 png_bytep buffer;
2390 png_size_t i;
2391 int state;
2392
2393 png_debug(1, "in png_handle_sCAL");
2394
2395 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2396 png_chunk_error(png_ptr, "missing IHDR");
2397
2398 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2399 {
2400 png_crc_finish(png_ptr, length);
2401 png_chunk_benign_error(png_ptr, "out of place");
2402 return;
2403 }
2404
2405 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sCAL) != 0)
2406 {
2407 png_crc_finish(png_ptr, length);
2408 png_chunk_benign_error(png_ptr, "duplicate");
2409 return;
2410 }
2411
2412 /* Need unit type, width, \0, height: minimum 4 bytes */
2413 else if (length < 4)
2414 {
2415 png_crc_finish(png_ptr, length);
2416 png_chunk_benign_error(png_ptr, "invalid");
2417 return;
2418 }
2419
2420 png_debug1(2, "Allocating and reading sCAL chunk data (%u bytes)",
2421 length + 1);
2422
2423 buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/);
2424
2425 if (buffer == NULL)
2426 {
2427 png_chunk_benign_error(png_ptr, "out of memory");
2428 png_crc_finish(png_ptr, length);
2429 return;
2430 }
2431
2432 png_crc_read(png_ptr, buffer, length);
2433 buffer[length] = 0; /* Null terminate the last string */
2434
2435 if (png_crc_finish(png_ptr, 0) != 0)
2436 return;
2437
2438 /* Validate the unit. */
2439 if (buffer[0] != 1 && buffer[0] != 2)
2440 {
2441 png_chunk_benign_error(png_ptr, "invalid unit");
2442 return;
2443 }
2444
2445 /* Validate the ASCII numbers, need two ASCII numbers separated by
2446 * a '\0' and they need to fit exactly in the chunk data.
2447 */
2448 i = 1;
2449 state = 0;
2450
2451 if (png_check_fp_number((png_const_charp)buffer, length, &state, &i) == 0 ||
2452 i >= length || buffer[i++] != 0)
2453 png_chunk_benign_error(png_ptr, "bad width format");
2454
2455 else if (PNG_FP_IS_POSITIVE(state) == 0)
2456 png_chunk_benign_error(png_ptr, "non-positive width");
2457
2458 else
2459 {
2460 png_size_t heighti = i;
2461
2462 state = 0;
2463 if (png_check_fp_number((png_const_charp)buffer, length,
2464 &state, &i) == 0 || i != length)
2465 png_chunk_benign_error(png_ptr, "bad height format");
2466
2467 else if (PNG_FP_IS_POSITIVE(state) == 0)
2468 png_chunk_benign_error(png_ptr, "non-positive height");
2469
2470 else
2471 /* This is the (only) success case. */
2472 png_set_sCAL_s(png_ptr, info_ptr, buffer[0],
2473 (png_charp)buffer+1, (png_charp)buffer+heighti);
2474 }
2475 }
2476 #endif
2477
2478 #ifdef PNG_READ_tIME_SUPPORTED
2479 void /* PRIVATE */
2480 png_handle_tIME(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2481 {
2482 png_byte buf[7];
2483 png_time mod_time;
2484
2485 png_debug(1, "in png_handle_tIME");
2486
2487 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2488 png_chunk_error(png_ptr, "missing IHDR");
2489
2490 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tIME) != 0)
2491 {
2492 png_crc_finish(png_ptr, length);
2493 png_chunk_benign_error(png_ptr, "duplicate");
2494 return;
2495 }
2496
2497 if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2498 png_ptr->mode |= PNG_AFTER_IDAT;
2499
2500 if (length != 7)
2501 {
2502 png_crc_finish(png_ptr, length);
2503 png_chunk_benign_error(png_ptr, "invalid");
2504 return;
2505 }
2506
2507 png_crc_read(png_ptr, buf, 7);
2508
2509 if (png_crc_finish(png_ptr, 0) != 0)
2510 return;
2511
2512 mod_time.second = buf[6];
2513 mod_time.minute = buf[5];
2514 mod_time.hour = buf[4];
2515 mod_time.day = buf[3];
2516 mod_time.month = buf[2];
2517 mod_time.year = png_get_uint_16(buf);
2518
2519 png_set_tIME(png_ptr, info_ptr, &mod_time);
2520 }
2521 #endif
2522
2523 #ifdef PNG_READ_tEXt_SUPPORTED
2524 /* Note: this does not properly handle chunks that are > 64K under DOS */
2525 void /* PRIVATE */
2526 png_handle_tEXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2527 {
2528 png_text text_info;
2529 png_bytep buffer;
2530 png_charp key;
2531 png_charp text;
2532 png_uint_32 skip = 0;
2533
2534 png_debug(1, "in png_handle_tEXt");
2535
2536 #ifdef PNG_USER_LIMITS_SUPPORTED
2537 if (png_ptr->user_chunk_cache_max != 0)
2538 {
2539 if (png_ptr->user_chunk_cache_max == 1)
2540 {
2541 png_crc_finish(png_ptr, length);
2542 return;
2543 }
2544
2545 if (--png_ptr->user_chunk_cache_max == 1)
2546 {
2547 png_crc_finish(png_ptr, length);
2548 png_chunk_benign_error(png_ptr, "no space in chunk cache");
2549 return;
2550 }
2551 }
2552 #endif
2553
2554 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2555 png_chunk_error(png_ptr, "missing IHDR");
2556
2557 if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2558 png_ptr->mode |= PNG_AFTER_IDAT;
2559
2560 #ifdef PNG_MAX_MALLOC_64K
2561 if (length > 65535U)
2562 {
2563 png_crc_finish(png_ptr, length);
2564 png_chunk_benign_error(png_ptr, "too large to fit in memory");
2565 return;
2566 }
2567 #endif
2568
2569 buffer = png_read_buffer(png_ptr, length+1, 1/*warn*/);
2570
2571 if (buffer == NULL)
2572 {
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, skip) != 0)
2580 return;
2581
2582 key = (png_charp)buffer;
2583 key[length] = 0;
2584
2585 for (text = key; *text; text++)
2586 /* Empty loop to find end of key */ ;
2587
2588 if (text != key + length)
2589 text++;
2590
2591 text_info.compression = PNG_TEXT_COMPRESSION_NONE;
2592 text_info.key = key;
2593 text_info.lang = NULL;
2594 text_info.lang_key = NULL;
2595 text_info.itxt_length = 0;
2596 text_info.text = text;
2597 text_info.text_length = strlen(text);
2598
2599 if (png_set_text_2(png_ptr, info_ptr, &text_info, 1) != 0)
2600 png_warning(png_ptr, "Insufficient memory to process text chunk");
2601 }
2602 #endif
2603
2604 #ifdef PNG_READ_zTXt_SUPPORTED
2605 /* Note: this does not correctly handle chunks that are > 64K under DOS */
2606 void /* PRIVATE */
2607 png_handle_zTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2608 {
2609 png_const_charp errmsg = NULL;
2610 png_bytep buffer;
2611 png_uint_32 keyword_length;
2612
2613 png_debug(1, "in png_handle_zTXt");
2614
2615 #ifdef PNG_USER_LIMITS_SUPPORTED
2616 if (png_ptr->user_chunk_cache_max != 0)
2617 {
2618 if (png_ptr->user_chunk_cache_max == 1)
2619 {
2620 png_crc_finish(png_ptr, length);
2621 return;
2622 }
2623
2624 if (--png_ptr->user_chunk_cache_max == 1)
2625 {
2626 png_crc_finish(png_ptr, length);
2627 png_chunk_benign_error(png_ptr, "no space in chunk cache");
2628 return;
2629 }
2630 }
2631 #endif
2632
2633 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2634 png_chunk_error(png_ptr, "missing IHDR");
2635
2636 if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2637 png_ptr->mode |= PNG_AFTER_IDAT;
2638
2639 /* Note, "length" is sufficient here; we won't be adding
2640 * a null terminator later.
2641 */
2642 buffer = png_read_buffer(png_ptr, length, 2/*silent*/);
2643
2644 if (buffer == NULL)
2645 {
2646 png_crc_finish(png_ptr, length);
2647 png_chunk_benign_error(png_ptr, "out of memory");
2648 return;
2649 }
2650
2651 png_crc_read(png_ptr, buffer, length);
2652
2653 if (png_crc_finish(png_ptr, 0) != 0)
2654 return;
2655
2656 /* TODO: also check that the keyword contents match the spec! */
2657 for (keyword_length = 0;
2658 keyword_length < length && buffer[keyword_length] != 0;
2659 ++keyword_length)
2660 /* Empty loop to find end of name */ ;
2661
2662 if (keyword_length > 79 || keyword_length < 1)
2663 errmsg = "bad keyword";
2664
2665 /* zTXt must have some LZ data after the keyword, although it may expand to
2666 * zero bytes; we need a '\0' at the end of the keyword, the compression type
2667 * then the LZ data:
2668 */
2669 else if (keyword_length + 3 > length)
2670 errmsg = "truncated";
2671
2672 else if (buffer[keyword_length+1] != PNG_COMPRESSION_TYPE_BASE)
2673 errmsg = "unknown compression type";
2674
2675 else
2676 {
2677 png_alloc_size_t uncompressed_length = PNG_SIZE_MAX;
2678
2679 /* TODO: at present png_decompress_chunk imposes a single application
2680 * level memory limit, this should be split to different values for iCCP
2681 * and text chunks.
2682 */
2683 if (png_decompress_chunk(png_ptr, length, keyword_length+2,
2684 &uncompressed_length, 1/*terminate*/) == Z_STREAM_END)
2685 {
2686 png_text text;
2687
2688 if (png_ptr->read_buffer == NULL)
2689 errmsg="Read failure in png_handle_zTXt";
2690 else
2691 {
2692 /* It worked; png_ptr->read_buffer now looks like a tEXt chunk
2693 * except for the extra compression type byte and the fact that
2694 * it isn't necessarily '\0' terminated.
2695 */
2696 buffer = png_ptr->read_buffer;
2697 buffer[uncompressed_length+(keyword_length+2)] = 0;
2698
2699 text.compression = PNG_TEXT_COMPRESSION_zTXt;
2700 text.key = (png_charp)buffer;
2701 text.text = (png_charp)(buffer + keyword_length+2);
2702 text.text_length = uncompressed_length;
2703 text.itxt_length = 0;
2704 text.lang = NULL;
2705 text.lang_key = NULL;
2706
2707 if (png_set_text_2(png_ptr, info_ptr, &text, 1) != 0)
2708 errmsg = "insufficient memory";
2709 }
2710 }
2711
2712 else
2713 errmsg = png_ptr->zstream.msg;
2714 }
2715
2716 if (errmsg != NULL)
2717 png_chunk_benign_error(png_ptr, errmsg);
2718 }
2719 #endif
2720
2721 #ifdef PNG_READ_iTXt_SUPPORTED
2722 /* Note: this does not correctly handle chunks that are > 64K under DOS */
2723 void /* PRIVATE */
2724 png_handle_iTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2725 {
2726 png_const_charp errmsg = NULL;
2727 png_bytep buffer;
2728 png_uint_32 prefix_length;
2729
2730 png_debug(1, "in png_handle_iTXt");
2731
2732 #ifdef PNG_USER_LIMITS_SUPPORTED
2733 if (png_ptr->user_chunk_cache_max != 0)
2734 {
2735 if (png_ptr->user_chunk_cache_max == 1)
2736 {
2737 png_crc_finish(png_ptr, length);
2738 return;
2739 }
2740
2741 if (--png_ptr->user_chunk_cache_max == 1)
2742 {
2743 png_crc_finish(png_ptr, length);
2744 png_chunk_benign_error(png_ptr, "no space in chunk cache");
2745 return;
2746 }
2747 }
2748 #endif
2749
2750 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2751 png_chunk_error(png_ptr, "missing IHDR");
2752
2753 if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2754 png_ptr->mode |= PNG_AFTER_IDAT;
2755
2756 buffer = png_read_buffer(png_ptr, length+1, 1/*warn*/);
2757
2758 if (buffer == NULL)
2759 {
2760 png_crc_finish(png_ptr, length);
2761 png_chunk_benign_error(png_ptr, "out of memory");
2762 return;
2763 }
2764
2765 png_crc_read(png_ptr, buffer, length);
2766
2767 if (png_crc_finish(png_ptr, 0) != 0)
2768 return;
2769
2770 /* First the keyword. */
2771 for (prefix_length=0;
2772 prefix_length < length && buffer[prefix_length] != 0;
2773 ++prefix_length)
2774 /* Empty loop */ ;
2775
2776 /* Perform a basic check on the keyword length here. */
2777 if (prefix_length > 79 || prefix_length < 1)
2778 errmsg = "bad keyword";
2779
2780 /* Expect keyword, compression flag, compression type, language, translated
2781 * keyword (both may be empty but are 0 terminated) then the text, which may
2782 * be empty.
2783 */
2784 else if (prefix_length + 5 > length)
2785 errmsg = "truncated";
2786
2787 else if (buffer[prefix_length+1] == 0 ||
2788 (buffer[prefix_length+1] == 1 &&
2789 buffer[prefix_length+2] == PNG_COMPRESSION_TYPE_BASE))
2790 {
2791 int compressed = buffer[prefix_length+1] != 0;
2792 png_uint_32 language_offset, translated_keyword_offset;
2793 png_alloc_size_t uncompressed_length = 0;
2794
2795 /* Now the language tag */
2796 prefix_length += 3;
2797 language_offset = prefix_length;
2798
2799 for (; prefix_length < length && buffer[prefix_length] != 0;
2800 ++prefix_length)
2801 /* Empty loop */ ;
2802
2803 /* WARNING: the length may be invalid here, this is checked below. */
2804 translated_keyword_offset = ++prefix_length;
2805
2806 for (; prefix_length < length && buffer[prefix_length] != 0;
2807 ++prefix_length)
2808 /* Empty loop */ ;
2809
2810 /* prefix_length should now be at the trailing '\0' of the translated
2811 * keyword, but it may already be over the end. None of this arithmetic
2812 * can overflow because chunks are at most 2^31 bytes long, but on 16-bit
2813 * systems the available allocation may overflow.
2814 */
2815 ++prefix_length;
2816
2817 if (compressed == 0 && prefix_length <= length)
2818 uncompressed_length = length - prefix_length;
2819
2820 else if (compressed != 0 && prefix_length < length)
2821 {
2822 uncompressed_length = PNG_SIZE_MAX;
2823
2824 /* TODO: at present png_decompress_chunk imposes a single application
2825 * level memory limit, this should be split to different values for
2826 * iCCP and text chunks.
2827 */
2828 if (png_decompress_chunk(png_ptr, length, prefix_length,
2829 &uncompressed_length, 1/*terminate*/) == Z_STREAM_END)
2830 buffer = png_ptr->read_buffer;
2831
2832 else
2833 errmsg = png_ptr->zstream.msg;
2834 }
2835
2836 else
2837 errmsg = "truncated";
2838
2839 if (errmsg == NULL)
2840 {
2841 png_text text;
2842
2843 buffer[uncompressed_length+prefix_length] = 0;
2844
2845 if (compressed == 0)
2846 text.compression = PNG_ITXT_COMPRESSION_NONE;
2847
2848 else
2849 text.compression = PNG_ITXT_COMPRESSION_zTXt;
2850
2851 text.key = (png_charp)buffer;
2852 text.lang = (png_charp)buffer + language_offset;
2853 text.lang_key = (png_charp)buffer + translated_keyword_offset;
2854 text.text = (png_charp)buffer + prefix_length;
2855 text.text_length = 0;
2856 text.itxt_length = uncompressed_length;
2857
2858 if (png_set_text_2(png_ptr, info_ptr, &text, 1) != 0)
2859 errmsg = "insufficient memory";
2860 }
2861 }
2862
2863 else
2864 errmsg = "bad compression info";
2865
2866 if (errmsg != NULL)
2867 png_chunk_benign_error(png_ptr, errmsg);
2868 }
2869 #endif
2870
2871 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
2872 /* Utility function for png_handle_unknown; set up png_ptr::unknown_chunk */
2873 static int
2874 png_cache_unknown_chunk(png_structrp png_ptr, png_uint_32 length)
2875 {
2876 png_alloc_size_t limit = PNG_SIZE_MAX;
2877
2878 if (png_ptr->unknown_chunk.data != NULL)
2879 {
2880 png_free(png_ptr, png_ptr->unknown_chunk.data);
2881 png_ptr->unknown_chunk.data = NULL;
2882 }
2883
2884 # ifdef PNG_SET_USER_LIMITS_SUPPORTED
2885 if (png_ptr->user_chunk_malloc_max > 0 &&
2886 png_ptr->user_chunk_malloc_max < limit)
2887 limit = png_ptr->user_chunk_malloc_max;
2888
2889 # elif PNG_USER_CHUNK_MALLOC_MAX > 0
2890 if (PNG_USER_CHUNK_MALLOC_MAX < limit)
2891 limit = PNG_USER_CHUNK_MALLOC_MAX;
2892 # endif
2893
2894 if (length <= limit)
2895 {
2896 PNG_CSTRING_FROM_CHUNK(png_ptr->unknown_chunk.name, png_ptr->chunk_name);
2897 /* The following is safe because of the PNG_SIZE_MAX init above */
2898 png_ptr->unknown_chunk.size = (png_size_t)length/*SAFE*/;
2899 /* 'mode' is a flag array, only the bottom four bits matter here */
2900 png_ptr->unknown_chunk.location = (png_byte)png_ptr->mode/*SAFE*/;
2901
2902 if (length == 0)
2903 png_ptr->unknown_chunk.data = NULL;
2904
2905 else
2906 {
2907 /* Do a 'warn' here - it is handled below. */
2908 png_ptr->unknown_chunk.data = png_voidcast(png_bytep,
2909 png_malloc_warn(png_ptr, length));
2910 }
2911 }
2912
2913 if (png_ptr->unknown_chunk.data == NULL && length > 0)
2914 {
2915 /* This is benign because we clean up correctly */
2916 png_crc_finish(png_ptr, length);
2917 png_chunk_benign_error(png_ptr, "unknown chunk exceeds memory limits");
2918 return 0;
2919 }
2920
2921 else
2922 {
2923 if (length > 0)
2924 png_crc_read(png_ptr, png_ptr->unknown_chunk.data, length);
2925 png_crc_finish(png_ptr, 0);
2926 return 1;
2927 }
2928 }
2929 #endif /* READ_UNKNOWN_CHUNKS */
2930
2931 /* Handle an unknown, or known but disabled, chunk */
2932 void /* PRIVATE */
2933 png_handle_unknown(png_structrp png_ptr, png_inforp info_ptr,
2934 png_uint_32 length, int keep)
2935 {
2936 int handled = 0; /* the chunk was handled */
2937
2938 png_debug(1, "in png_handle_unknown");
2939
2940 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
2941 /* NOTE: this code is based on the code in libpng-1.4.12 except for fixing
2942 * the bug which meant that setting a non-default behavior for a specific
2943 * chunk would be ignored (the default was always used unless a user
2944 * callback was installed).
2945 *
2946 * 'keep' is the value from the png_chunk_unknown_handling, the setting for
2947 * this specific chunk_name, if PNG_HANDLE_AS_UNKNOWN_SUPPORTED, if not it
2948 * will always be PNG_HANDLE_CHUNK_AS_DEFAULT and it needs to be set here.
2949 * This is just an optimization to avoid multiple calls to the lookup
2950 * function.
2951 */
2952 # ifndef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
2953 # ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
2954 keep = png_chunk_unknown_handling(png_ptr, png_ptr->chunk_name);
2955 # endif
2956 # endif
2957
2958 /* One of the following methods will read the chunk or skip it (at least one
2959 * of these is always defined because this is the only way to switch on
2960 * PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
2961 */
2962 # ifdef PNG_READ_USER_CHUNKS_SUPPORTED
2963 /* The user callback takes precedence over the chunk keep value, but the
2964 * keep value is still required to validate a save of a critical chunk.
2965 */
2966 if (png_ptr->read_user_chunk_fn != NULL)
2967 {
2968 if (png_cache_unknown_chunk(png_ptr, length) != 0)
2969 {
2970 /* Callback to user unknown chunk handler */
2971 int ret = (*(png_ptr->read_user_chunk_fn))(png_ptr,
2972 &png_ptr->unknown_chunk);
2973
2974 /* ret is:
2975 * negative: An error occurred; png_chunk_error will be called.
2976 * zero: The chunk was not handled, the chunk will be discarded
2977 * unless png_set_keep_unknown_chunks has been used to set
2978 * a 'keep' behavior for this particular chunk, in which
2979 * case that will be used. A critical chunk will cause an
2980 * error at this point unless it is to be saved.
2981 * positive: The chunk was handled, libpng will ignore/discard it.
2982 */
2983 if (ret < 0)
2984 png_chunk_error(png_ptr, "error in user chunk");
2985
2986 else if (ret == 0)
2987 {
2988 /* If the keep value is 'default' or 'never' override it, but
2989 * still error out on critical chunks unless the keep value is
2990 * 'always' While this is weird it is the behavior in 1.4.12.
2991 * A possible improvement would be to obey the value set for the
2992 * chunk, but this would be an API change that would probably
2993 * damage some applications.
2994 *
2995 * The png_app_warning below catches the case that matters, where
2996 * the application has not set specific save or ignore for this
2997 * chunk or global save or ignore.
2998 */
2999 if (keep < PNG_HANDLE_CHUNK_IF_SAFE)
3000 {
3001 # ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
3002 if (png_ptr->unknown_default < PNG_HANDLE_CHUNK_IF_SAFE)
3003 {
3004 png_chunk_warning(png_ptr, "Saving unknown chunk:");
3005 png_app_warning(png_ptr,
3006 "forcing save of an unhandled chunk;"
3007 " please call png_set_keep_unknown_chunks");
3008 /* with keep = PNG_HANDLE_CHUNK_IF_SAFE */
3009 }
3010 # endif
3011 keep = PNG_HANDLE_CHUNK_IF_SAFE;
3012 }
3013 }
3014
3015 else /* chunk was handled */
3016 {
3017 handled = 1;
3018 /* Critical chunks can be safely discarded at this point. */
3019 keep = PNG_HANDLE_CHUNK_NEVER;
3020 }
3021 }
3022
3023 else
3024 keep = PNG_HANDLE_CHUNK_NEVER; /* insufficient memory */
3025 }
3026
3027 else
3028 /* Use the SAVE_UNKNOWN_CHUNKS code or skip the chunk */
3029 # endif /* READ_USER_CHUNKS */
3030
3031 # ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED
3032 {
3033 /* keep is currently just the per-chunk setting, if there was no
3034 * setting change it to the global default now (not that this may
3035 * still be AS_DEFAULT) then obtain the cache of the chunk if required,
3036 * if not simply skip the chunk.
3037 */
3038 if (keep == PNG_HANDLE_CHUNK_AS_DEFAULT)
3039 keep = png_ptr->unknown_default;
3040
3041 if (keep == PNG_HANDLE_CHUNK_ALWAYS ||
3042 (keep == PNG_HANDLE_CHUNK_IF_SAFE &&
3043 PNG_CHUNK_ANCILLARY(png_ptr->chunk_name)))
3044 {
3045 if (png_cache_unknown_chunk(png_ptr, length) == 0)
3046 keep = PNG_HANDLE_CHUNK_NEVER;
3047 }
3048
3049 else
3050 png_crc_finish(png_ptr, length);
3051 }
3052 # else
3053 # ifndef PNG_READ_USER_CHUNKS_SUPPORTED
3054 # error no method to support READ_UNKNOWN_CHUNKS
3055 # endif
3056
3057 {
3058 /* If here there is no read callback pointer set and no support is
3059 * compiled in to just save the unknown chunks, so simply skip this
3060 * chunk. If 'keep' is something other than AS_DEFAULT or NEVER then
3061 * the app has erroneously asked for unknown chunk saving when there
3062 * is no support.
3063 */
3064 if (keep > PNG_HANDLE_CHUNK_NEVER)
3065 png_app_error(png_ptr, "no unknown chunk support available");
3066
3067 png_crc_finish(png_ptr, length);
3068 }
3069 # endif
3070
3071 # ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
3072 /* Now store the chunk in the chunk list if appropriate, and if the limits
3073 * permit it.
3074 */
3075 if (keep == PNG_HANDLE_CHUNK_ALWAYS ||
3076 (keep == PNG_HANDLE_CHUNK_IF_SAFE &&
3077 PNG_CHUNK_ANCILLARY(png_ptr->chunk_name)))
3078 {
3079 # ifdef PNG_USER_LIMITS_SUPPORTED
3080 switch (png_ptr->user_chunk_cache_max)
3081 {
3082 case 2:
3083 png_ptr->user_chunk_cache_max = 1;
3084 png_chunk_benign_error(png_ptr, "no space in chunk cache");
3085 /* FALLTHROUGH */
3086 case 1:
3087 /* NOTE: prior to 1.6.0 this case resulted in an unknown critical
3088 * chunk being skipped, now there will be a hard error below.
3089 */
3090 break;
3091
3092 default: /* not at limit */
3093 --(png_ptr->user_chunk_cache_max);
3094 /* FALLTHROUGH */
3095 case 0: /* no limit */
3096 # endif /* USER_LIMITS */
3097 /* Here when the limit isn't reached or when limits are compiled
3098 * out; store the chunk.
3099 */
3100 png_set_unknown_chunks(png_ptr, info_ptr,
3101 &png_ptr->unknown_chunk, 1);
3102 handled = 1;
3103 # ifdef PNG_USER_LIMITS_SUPPORTED
3104 break;
3105 }
3106 # endif
3107 }
3108 # else /* no store support: the chunk must be handled by the user callback */
3109 PNG_UNUSED(info_ptr)
3110 # endif
3111
3112 /* Regardless of the error handling below the cached data (if any) can be
3113 * freed now. Notice that the data is not freed if there is a png_error, but
3114 * it will be freed by destroy_read_struct.
3115 */
3116 if (png_ptr->unknown_chunk.data != NULL)
3117 png_free(png_ptr, png_ptr->unknown_chunk.data);
3118 png_ptr->unknown_chunk.data = NULL;
3119
3120 #else /* !PNG_READ_UNKNOWN_CHUNKS_SUPPORTED */
3121 /* There is no support to read an unknown chunk, so just skip it. */
3122 png_crc_finish(png_ptr, length);
3123 PNG_UNUSED(info_ptr)
3124 PNG_UNUSED(keep)
3125 #endif /* !READ_UNKNOWN_CHUNKS */
3126
3127 /* Check for unhandled critical chunks */
3128 if (handled == 0 && PNG_CHUNK_CRITICAL(png_ptr->chunk_name))
3129 png_chunk_error(png_ptr, "unhandled critical chunk");
3130 }
3131
3132 /* This function is called to verify that a chunk name is valid.
3133 * This function can't have the "critical chunk check" incorporated
3134 * into it, since in the future we will need to be able to call user
3135 * functions to handle unknown critical chunks after we check that
3136 * the chunk name itself is valid.
3137 */
3138
3139 /* Bit hacking: the test for an invalid byte in the 4 byte chunk name is:
3140 *
3141 * ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97))
3142 */
3143
3144 void /* PRIVATE */
3145 png_check_chunk_name(png_const_structrp png_ptr, const png_uint_32 chunk_name)
3146 {
3147 int i;
3148 png_uint_32 cn=chunk_name;
3149
3150 png_debug(1, "in png_check_chunk_name");
3151
3152 for (i=1; i<=4; ++i)
3153 {
3154 int c = cn & 0xff;
3155
3156 if (c < 65 || c > 122 || (c > 90 && c < 97))
3157 png_chunk_error(png_ptr, "invalid chunk type");
3158
3159 cn >>= 8;
3160 }
3161 }
3162
3163 void /* PRIVATE */
3164 png_check_chunk_length(png_const_structrp png_ptr, const png_uint_32 length)
3165 {
3166 png_alloc_size_t limit = PNG_UINT_31_MAX;
3167
3168 # ifdef PNG_SET_USER_LIMITS_SUPPORTED
3169 if (png_ptr->user_chunk_malloc_max > 0 &&
3170 png_ptr->user_chunk_malloc_max < limit)
3171 limit = png_ptr->user_chunk_malloc_max;
3172 # elif PNG_USER_CHUNK_MALLOC_MAX > 0
3173 if (PNG_USER_CHUNK_MALLOC_MAX < limit)
3174 limit = PNG_USER_CHUNK_MALLOC_MAX;
3175 # endif
3176 if (png_ptr->chunk_name == png_IDAT)
3177 {
3178 png_alloc_size_t idat_limit = PNG_UINT_31_MAX;
3179 size_t row_factor =
3180 (png_ptr->width * png_ptr->channels * (png_ptr->bit_depth > 8? 2: 1)
3181 + 1 + (png_ptr->interlaced? 6: 0));
3182 if (png_ptr->height > PNG_UINT_32_MAX/row_factor)
3183 idat_limit=PNG_UINT_31_MAX;
3184 else
3185 idat_limit = png_ptr->height * row_factor;
3186 row_factor = row_factor > 32566? 32566 : row_factor;
3187 idat_limit += 6 + 5*(idat_limit/row_factor+1); /* zlib+deflate overhead */
3188 idat_limit=idat_limit < PNG_UINT_31_MAX? idat_limit : PNG_UINT_31_MAX;
3189 limit = limit < idat_limit? idat_limit : limit;
3190 }
3191
3192 if (length > limit)
3193 {
3194 png_debug2(0," length = %lu, limit = %lu",
3195 (unsigned long)length,(unsigned long)limit);
3196 png_chunk_error(png_ptr, "chunk data is too large");
3197 }
3198 }
3199
3200 /* Combines the row recently read in with the existing pixels in the row. This
3201 * routine takes care of alpha and transparency if requested. This routine also
3202 * handles the two methods of progressive display of interlaced images,
3203 * depending on the 'display' value; if 'display' is true then the whole row
3204 * (dp) is filled from the start by replicating the available pixels. If
3205 * 'display' is false only those pixels present in the pass are filled in.
3206 */
3207 void /* PRIVATE */
3208 png_combine_row(png_const_structrp png_ptr, png_bytep dp, int display)
3209 {
3210 unsigned int pixel_depth = png_ptr->transformed_pixel_depth;
3211 png_const_bytep sp = png_ptr->row_buf + 1;
3212 png_alloc_size_t row_width = png_ptr->width;
3213 unsigned int pass = png_ptr->pass;
3214 png_bytep end_ptr = 0;
3215 png_byte end_byte = 0;
3216 unsigned int end_mask;
3217
3218 png_debug(1, "in png_combine_row");
3219
3220 /* Added in 1.5.6: it should not be possible to enter this routine until at
3221 * least one row has been read from the PNG data and transformed.
3222 */
3223 if (pixel_depth == 0)
3224 png_error(png_ptr, "internal row logic error");
3225
3226 /* Added in 1.5.4: the pixel depth should match the information returned by
3227 * any call to png_read_update_info at this point. Do not continue if we got
3228 * this wrong.
3229 */
3230 if (png_ptr->info_rowbytes != 0 && png_ptr->info_rowbytes !=
3231 PNG_ROWBYTES(pixel_depth, row_width))
3232 png_error(png_ptr, "internal row size calculation error");
3233
3234 /* Don't expect this to ever happen: */
3235 if (row_width == 0)
3236 png_error(png_ptr, "internal row width error");
3237
3238 /* Preserve the last byte in cases where only part of it will be overwritten,
3239 * the multiply below may overflow, we don't care because ANSI-C guarantees
3240 * we get the low bits.
3241 */
3242 end_mask = (pixel_depth * row_width) & 7;
3243 if (end_mask != 0)
3244 {
3245 /* end_ptr == NULL is a flag to say do nothing */
3246 end_ptr = dp + PNG_ROWBYTES(pixel_depth, row_width) - 1;
3247 end_byte = *end_ptr;
3248 # ifdef PNG_READ_PACKSWAP_SUPPORTED
3249 if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
3250 /* little-endian byte */
3251 end_mask = (unsigned int)(0xff << end_mask);
3252
3253 else /* big-endian byte */
3254 # endif
3255 end_mask = 0xff >> end_mask;
3256 /* end_mask is now the bits to *keep* from the destination row */
3257 }
3258
3259 /* For non-interlaced images this reduces to a memcpy(). A memcpy()
3260 * will also happen if interlacing isn't supported or if the application
3261 * does not call png_set_interlace_handling(). In the latter cases the
3262 * caller just gets a sequence of the unexpanded rows from each interlace
3263 * pass.
3264 */
3265 #ifdef PNG_READ_INTERLACING_SUPPORTED
3266 if (png_ptr->interlaced != 0 &&
3267 (png_ptr->transformations & PNG_INTERLACE) != 0 &&
3268 pass < 6 && (display == 0 ||
3269 /* The following copies everything for 'display' on passes 0, 2 and 4. */
3270 (display == 1 && (pass & 1) != 0)))
3271 {
3272 /* Narrow images may have no bits in a pass; the caller should handle
3273 * this, but this test is cheap:
3274 */
3275 if (row_width <= PNG_PASS_START_COL(pass))
3276 return;
3277
3278 if (pixel_depth < 8)
3279 {
3280 /* For pixel depths up to 4 bpp the 8-pixel mask can be expanded to fit
3281 * into 32 bits, then a single loop over the bytes using the four byte
3282 * values in the 32-bit mask can be used. For the 'display' option the
3283 * expanded mask may also not require any masking within a byte. To
3284 * make this work the PACKSWAP option must be taken into account - it
3285 * simply requires the pixels to be reversed in each byte.
3286 *
3287 * The 'regular' case requires a mask for each of the first 6 passes,
3288 * the 'display' case does a copy for the even passes in the range
3289 * 0..6. This has already been handled in the test above.
3290 *
3291 * The masks are arranged as four bytes with the first byte to use in
3292 * the lowest bits (little-endian) regardless of the order (PACKSWAP or
3293 * not) of the pixels in each byte.
3294 *
3295 * NOTE: the whole of this logic depends on the caller of this function
3296 * only calling it on rows appropriate to the pass. This function only
3297 * understands the 'x' logic; the 'y' logic is handled by the caller.
3298 *
3299 * The following defines allow generation of compile time constant bit
3300 * masks for each pixel depth and each possibility of swapped or not
3301 * swapped bytes. Pass 'p' is in the range 0..6; 'x', a pixel index,
3302 * is in the range 0..7; and the result is 1 if the pixel is to be
3303 * copied in the pass, 0 if not. 'S' is for the sparkle method, 'B'
3304 * for the block method.
3305 *
3306 * With some compilers a compile time expression of the general form:
3307 *
3308 * (shift >= 32) ? (a >> (shift-32)) : (b >> shift)
3309 *
3310 * Produces warnings with values of 'shift' in the range 33 to 63
3311 * because the right hand side of the ?: expression is evaluated by
3312 * the compiler even though it isn't used. Microsoft Visual C (various
3313 * versions) and the Intel C compiler are known to do this. To avoid
3314 * this the following macros are used in 1.5.6. This is a temporary
3315 * solution to avoid destabilizing the code during the release process.
3316 */
3317 # if PNG_USE_COMPILE_TIME_MASKS
3318 # define PNG_LSR(x,s) ((x)>>((s) & 0x1f))
3319 # define PNG_LSL(x,s) ((x)<<((s) & 0x1f))
3320 # else
3321 # define PNG_LSR(x,s) ((x)>>(s))
3322 # define PNG_LSL(x,s) ((x)<<(s))
3323 # endif
3324 # define S_COPY(p,x) (((p)<4 ? PNG_LSR(0x80088822,(3-(p))*8+(7-(x))) :\
3325 PNG_LSR(0xaa55ff00,(7-(p))*8+(7-(x)))) & 1)
3326 # define B_COPY(p,x) (((p)<4 ? PNG_LSR(0xff0fff33,(3-(p))*8+(7-(x))) :\
3327 PNG_LSR(0xff55ff00,(7-(p))*8+(7-(x)))) & 1)
3328
3329 /* Return a mask for pass 'p' pixel 'x' at depth 'd'. The mask is
3330 * little endian - the first pixel is at bit 0 - however the extra
3331 * parameter 's' can be set to cause the mask position to be swapped
3332 * within each byte, to match the PNG format. This is done by XOR of
3333 * the shift with 7, 6 or 4 for bit depths 1, 2 and 4.
3334 */
3335 # define PIXEL_MASK(p,x,d,s) \
3336 (PNG_LSL(((PNG_LSL(1U,(d)))-1),(((x)*(d))^((s)?8-(d):0))))
3337
3338 /* Hence generate the appropriate 'block' or 'sparkle' pixel copy mask.
3339 */
3340 # define S_MASKx(p,x,d,s) (S_COPY(p,x)?PIXEL_MASK(p,x,d,s):0)
3341 # define B_MASKx(p,x,d,s) (B_COPY(p,x)?PIXEL_MASK(p,x,d,s):0)
3342
3343 /* Combine 8 of these to get the full mask. For the 1-bpp and 2-bpp
3344 * cases the result needs replicating, for the 4-bpp case the above
3345 * generates a full 32 bits.
3346 */
3347 # define MASK_EXPAND(m,d) ((m)*((d)==1?0x01010101:((d)==2?0x00010001:1)))
3348
3349 # define S_MASK(p,d,s) MASK_EXPAND(S_MASKx(p,0,d,s) + S_MASKx(p,1,d,s) +\
3350 S_MASKx(p,2,d,s) + S_MASKx(p,3,d,s) + S_MASKx(p,4,d,s) +\
3351 S_MASKx(p,5,d,s) + S_MASKx(p,6,d,s) + S_MASKx(p,7,d,s), d)
3352
3353 # define B_MASK(p,d,s) MASK_EXPAND(B_MASKx(p,0,d,s) + B_MASKx(p,1,d,s) +\
3354 B_MASKx(p,2,d,s) + B_MASKx(p,3,d,s) + B_MASKx(p,4,d,s) +\
3355 B_MASKx(p,5,d,s) + B_MASKx(p,6,d,s) + B_MASKx(p,7,d,s), d)
3356
3357 #if PNG_USE_COMPILE_TIME_MASKS
3358 /* Utility macros to construct all the masks for a depth/swap
3359 * combination. The 's' parameter says whether the format is PNG
3360 * (big endian bytes) or not. Only the three odd-numbered passes are
3361 * required for the display/block algorithm.
3362 */
3363 # define S_MASKS(d,s) { S_MASK(0,d,s), S_MASK(1,d,s), S_MASK(2,d,s),\
3364 S_MASK(3,d,s), S_MASK(4,d,s), S_MASK(5,d,s) }
3365
3366 # define B_MASKS(d,s) { B_MASK(1,d,s), B_MASK(3,d,s), B_MASK(5,d,s) }
3367
3368 # define DEPTH_INDEX(d) ((d)==1?0:((d)==2?1:2))
3369
3370 /* Hence the pre-compiled masks indexed by PACKSWAP (or not), depth and
3371 * then pass:
3372 */
3373 static PNG_CONST png_uint_32 row_mask[2/*PACKSWAP*/][3/*depth*/][6] =
3374 {
3375 /* Little-endian byte masks for PACKSWAP */
3376 { S_MASKS(1,0), S_MASKS(2,0), S_MASKS(4,0) },
3377 /* Normal (big-endian byte) masks - PNG format */
3378 { S_MASKS(1,1), S_MASKS(2,1), S_MASKS(4,1) }
3379 };
3380
3381 /* display_mask has only three entries for the odd passes, so index by
3382 * pass>>1.
3383 */
3384 static PNG_CONST png_uint_32 display_mask[2][3][3] =
3385 {
3386 /* Little-endian byte masks for PACKSWAP */
3387 { B_MASKS(1,0), B_MASKS(2,0), B_MASKS(4,0) },
3388 /* Normal (big-endian byte) masks - PNG format */
3389 { B_MASKS(1,1), B_MASKS(2,1), B_MASKS(4,1) }
3390 };
3391
3392 # define MASK(pass,depth,display,png)\
3393 ((display)?display_mask[png][DEPTH_INDEX(depth)][pass>>1]:\
3394 row_mask[png][DEPTH_INDEX(depth)][pass])
3395
3396 #else /* !PNG_USE_COMPILE_TIME_MASKS */
3397 /* This is the runtime alternative: it seems unlikely that this will
3398 * ever be either smaller or faster than the compile time approach.
3399 */
3400 # define MASK(pass,depth,display,png)\
3401 ((display)?B_MASK(pass,depth,png):S_MASK(pass,depth,png))
3402 #endif /* !USE_COMPILE_TIME_MASKS */
3403
3404 /* Use the appropriate mask to copy the required bits. In some cases
3405 * the byte mask will be 0 or 0xff; optimize these cases. row_width is
3406 * the number of pixels, but the code copies bytes, so it is necessary
3407 * to special case the end.
3408 */
3409 png_uint_32 pixels_per_byte = 8 / pixel_depth;
3410 png_uint_32 mask;
3411
3412 # ifdef PNG_READ_PACKSWAP_SUPPORTED
3413 if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
3414 mask = MASK(pass, pixel_depth, display, 0);
3415
3416 else
3417 # endif
3418 mask = MASK(pass, pixel_depth, display, 1);
3419
3420 for (;;)
3421 {
3422 png_uint_32 m;
3423
3424 /* It doesn't matter in the following if png_uint_32 has more than
3425 * 32 bits because the high bits always match those in m<<24; it is,
3426 * however, essential to use OR here, not +, because of this.
3427 */
3428 m = mask;
3429 mask = (m >> 8) | (m << 24); /* rotate right to good compilers */
3430 m &= 0xff;
3431
3432 if (m != 0) /* something to copy */
3433 {
3434 if (m != 0xff)
3435 *dp = (png_byte)((*dp & ~m) | (*sp & m));
3436 else
3437 *dp = *sp;
3438 }
3439
3440 /* NOTE: this may overwrite the last byte with garbage if the image
3441 * is not an exact number of bytes wide; libpng has always done
3442 * this.
3443 */
3444 if (row_width <= pixels_per_byte)
3445 break; /* May need to restore part of the last byte */
3446
3447 row_width -= pixels_per_byte;
3448 ++dp;
3449 ++sp;
3450 }
3451 }
3452
3453 else /* pixel_depth >= 8 */
3454 {
3455 unsigned int bytes_to_copy, bytes_to_jump;
3456
3457 /* Validate the depth - it must be a multiple of 8 */
3458 if (pixel_depth & 7)
3459 png_error(png_ptr, "invalid user transform pixel depth");
3460
3461 pixel_depth >>= 3; /* now in bytes */
3462 row_width *= pixel_depth;
3463
3464 /* Regardless of pass number the Adam 7 interlace always results in a
3465 * fixed number of pixels to copy then to skip. There may be a
3466 * different number of pixels to skip at the start though.
3467 */
3468 {
3469 unsigned int offset = PNG_PASS_START_COL(pass) * pixel_depth;
3470
3471 row_width -= offset;
3472 dp += offset;
3473 sp += offset;
3474 }
3475
3476 /* Work out the bytes to copy. */
3477 if (display != 0)
3478 {
3479 /* When doing the 'block' algorithm the pixel in the pass gets
3480 * replicated to adjacent pixels. This is why the even (0,2,4,6)
3481 * passes are skipped above - the entire expanded row is copied.
3482 */
3483 bytes_to_copy = (1<<((6-pass)>>1)) * pixel_depth;
3484
3485 /* But don't allow this number to exceed the actual row width. */
3486 if (bytes_to_copy > row_width)
3487 bytes_to_copy = (unsigned int)/*SAFE*/row_width;
3488 }
3489
3490 else /* normal row; Adam7 only ever gives us one pixel to copy. */
3491 bytes_to_copy = pixel_depth;
3492
3493 /* In Adam7 there is a constant offset between where the pixels go. */
3494 bytes_to_jump = PNG_PASS_COL_OFFSET(pass) * pixel_depth;
3495
3496 /* And simply copy these bytes. Some optimization is possible here,
3497 * depending on the value of 'bytes_to_copy'. Special case the low
3498 * byte counts, which we know to be frequent.
3499 *
3500 * Notice that these cases all 'return' rather than 'break' - this
3501 * avoids an unnecessary test on whether to restore the last byte
3502 * below.
3503 */
3504 switch (bytes_to_copy)
3505 {
3506 case 1:
3507 for (;;)
3508 {
3509 *dp = *sp;
3510
3511 if (row_width <= bytes_to_jump)
3512 return;
3513
3514 dp += bytes_to_jump;
3515 sp += bytes_to_jump;
3516 row_width -= bytes_to_jump;
3517 }
3518
3519 case 2:
3520 /* There is a possibility of a partial copy at the end here; this
3521 * slows the code down somewhat.
3522 */
3523 do
3524 {
3525 dp[0] = sp[0]; dp[1] = sp[1];
3526
3527 if (row_width <= bytes_to_jump)
3528 return;
3529
3530 sp += bytes_to_jump;
3531 dp += bytes_to_jump;
3532 row_width -= bytes_to_jump;
3533 }
3534 while (row_width > 1);
3535
3536 /* And there can only be one byte left at this point: */
3537 *dp = *sp;
3538 return;
3539
3540 case 3:
3541 /* This can only be the RGB case, so each copy is exactly one
3542 * pixel and it is not necessary to check for a partial copy.
3543 */
3544 for (;;)
3545 {
3546 dp[0] = sp[0]; dp[1] = sp[1]; dp[2] = sp[2];
3547
3548 if (row_width <= bytes_to_jump)
3549 return;
3550
3551 sp += bytes_to_jump;
3552 dp += bytes_to_jump;
3553 row_width -= bytes_to_jump;
3554 }
3555
3556 default:
3557 #if PNG_ALIGN_TYPE != PNG_ALIGN_NONE
3558 /* Check for double byte alignment and, if possible, use a
3559 * 16-bit copy. Don't attempt this for narrow images - ones that
3560 * are less than an interlace panel wide. Don't attempt it for
3561 * wide bytes_to_copy either - use the memcpy there.
3562 */
3563 if (bytes_to_copy < 16 /*else use memcpy*/ &&
3564 png_isaligned(dp, png_uint_16) &&
3565 png_isaligned(sp, png_uint_16) &&
3566 bytes_to_copy % (sizeof (png_uint_16)) == 0 &&
3567 bytes_to_jump % (sizeof (png_uint_16)) == 0)
3568 {
3569 /* Everything is aligned for png_uint_16 copies, but try for
3570 * png_uint_32 first.
3571 */
3572 if (png_isaligned(dp, png_uint_32) &&
3573 png_isaligned(sp, png_uint_32) &&
3574 bytes_to_copy % (sizeof (png_uint_32)) == 0 &&
3575 bytes_to_jump % (sizeof (png_uint_32)) == 0)
3576 {
3577 png_uint_32p dp32 = png_aligncast(png_uint_32p,dp);
3578 png_const_uint_32p sp32 = png_aligncastconst(
3579 png_const_uint_32p, sp);
3580 size_t skip = (bytes_to_jump-bytes_to_copy) /
3581 (sizeof (png_uint_32));
3582
3583 do
3584 {
3585 size_t c = bytes_to_copy;
3586 do
3587 {
3588 *dp32++ = *sp32++;
3589 c -= (sizeof (png_uint_32));
3590 }
3591 while (c > 0);
3592
3593 if (row_width <= bytes_to_jump)
3594 return;
3595
3596 dp32 += skip;
3597 sp32 += skip;
3598 row_width -= bytes_to_jump;
3599 }
3600 while (bytes_to_copy <= row_width);
3601
3602 /* Get to here when the row_width truncates the final copy.
3603 * There will be 1-3 bytes left to copy, so don't try the
3604 * 16-bit loop below.
3605 */
3606 dp = (png_bytep)dp32;
3607 sp = (png_const_bytep)sp32;
3608 do
3609 *dp++ = *sp++;
3610 while (--row_width > 0);
3611 return;
3612 }
3613
3614 /* Else do it in 16-bit quantities, but only if the size is
3615 * not too large.
3616 */
3617 else
3618 {
3619 png_uint_16p dp16 = png_aligncast(png_uint_16p, dp);
3620 png_const_uint_16p sp16 = png_aligncastconst(
3621 png_const_uint_16p, sp);
3622 size_t skip = (bytes_to_jump-bytes_to_copy) /
3623 (sizeof (png_uint_16));
3624
3625 do
3626 {
3627 size_t c = bytes_to_copy;
3628 do
3629 {
3630 *dp16++ = *sp16++;
3631 c -= (sizeof (png_uint_16));
3632 }
3633 while (c > 0);
3634
3635 if (row_width <= bytes_to_jump)
3636 return;
3637
3638 dp16 += skip;
3639 sp16 += skip;
3640 row_width -= bytes_to_jump;
3641 }
3642 while (bytes_to_copy <= row_width);
3643
3644 /* End of row - 1 byte left, bytes_to_copy > row_width: */
3645 dp = (png_bytep)dp16;
3646 sp = (png_const_bytep)sp16;
3647 do
3648 *dp++ = *sp++;
3649 while (--row_width > 0);
3650 return;
3651 }
3652 }
3653 #endif /* ALIGN_TYPE code */
3654
3655 /* The true default - use a memcpy: */
3656 for (;;)
3657 {
3658 memcpy(dp, sp, bytes_to_copy);
3659
3660 if (row_width <= bytes_to_jump)
3661 return;
3662
3663 sp += bytes_to_jump;
3664 dp += bytes_to_jump;
3665 row_width -= bytes_to_jump;
3666 if (bytes_to_copy > row_width)
3667 bytes_to_copy = (unsigned int)/*SAFE*/row_width;
3668 }
3669 }
3670
3671 /* NOT REACHED*/
3672 } /* pixel_depth >= 8 */
3673
3674 /* Here if pixel_depth < 8 to check 'end_ptr' below. */
3675 }
3676 else
3677 #endif /* READ_INTERLACING */
3678
3679 /* If here then the switch above wasn't used so just memcpy the whole row
3680 * from the temporary row buffer (notice that this overwrites the end of the
3681 * destination row if it is a partial byte.)
3682 */
3683 memcpy(dp, sp, PNG_ROWBYTES(pixel_depth, row_width));
3684
3685 /* Restore the overwritten bits from the last byte if necessary. */
3686 if (end_ptr != NULL)
3687 *end_ptr = (png_byte)((end_byte & end_mask) | (*end_ptr & ~end_mask));
3688 }
3689
3690 #ifdef PNG_READ_INTERLACING_SUPPORTED
3691 void /* PRIVATE */
3692 png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass,
3693 png_uint_32 transformations /* Because these may affect the byte layout */)
3694 {
3695 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
3696 /* Offset to next interlace block */
3697 static PNG_CONST unsigned int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
3698
3699 png_debug(1, "in png_do_read_interlace");
3700 if (row != NULL && row_info != NULL)
3701 {
3702 png_uint_32 final_width;
3703
3704 final_width = row_info->width * png_pass_inc[pass];
3705
3706 switch (row_info->pixel_depth)
3707 {
3708 case 1:
3709 {
3710 png_bytep sp = row + (png_size_t)((row_info->width - 1) >> 3);
3711 png_bytep dp = row + (png_size_t)((final_width - 1) >> 3);
3712 unsigned int sshift, dshift;
3713 unsigned int s_start, s_end;
3714 int s_inc;
3715 int jstop = (int)png_pass_inc[pass];
3716 png_byte v;
3717 png_uint_32 i;
3718 int j;
3719
3720 #ifdef PNG_READ_PACKSWAP_SUPPORTED
3721 if ((transformations & PNG_PACKSWAP) != 0)
3722 {
3723 sshift = ((row_info->width + 7) & 0x07);
3724 dshift = ((final_width + 7) & 0x07);
3725 s_start = 7;
3726 s_end = 0;
3727 s_inc = -1;
3728 }
3729
3730 else
3731 #endif
3732 {
3733 sshift = 7 - ((row_info->width + 7) & 0x07);
3734 dshift = 7 - ((final_width + 7) & 0x07);
3735 s_start = 0;
3736 s_end = 7;
3737 s_inc = 1;
3738 }
3739
3740 for (i = 0; i < row_info->width; i++)
3741 {
3742 v = (png_byte)((*sp >> sshift) & 0x01);
3743 for (j = 0; j < jstop; j++)
3744 {
3745 unsigned int tmp = *dp & (0x7f7f >> (7 - dshift));
3746 tmp |= (unsigned int)(v << dshift);
3747 *dp = (png_byte)(tmp & 0xff);
3748
3749 if (dshift == s_end)
3750 {
3751 dshift = s_start;
3752 dp--;
3753 }
3754
3755 else
3756 dshift = (unsigned int)((int)dshift + s_inc);
3757 }
3758
3759 if (sshift == s_end)
3760 {
3761 sshift = s_start;
3762 sp--;
3763 }
3764
3765 else
3766 sshift = (unsigned int)((int)sshift + s_inc);
3767 }
3768 break;
3769 }
3770
3771 case 2:
3772 {
3773 png_bytep sp = row + (png_uint_32)((row_info->width - 1) >> 2);
3774 png_bytep dp = row + (png_uint_32)((final_width - 1) >> 2);
3775 unsigned int sshift, dshift;
3776 unsigned int s_start, s_end;
3777 int s_inc;
3778 int jstop = (int)png_pass_inc[pass];
3779 png_uint_32 i;
3780
3781 #ifdef PNG_READ_PACKSWAP_SUPPORTED
3782 if ((transformations & PNG_PACKSWAP) != 0)
3783 {
3784 sshift = (((row_info->width + 3) & 0x03) << 1);
3785 dshift = (((final_width + 3) & 0x03) << 1);
3786 s_start = 6;
3787 s_end = 0;
3788 s_inc = -2;
3789 }
3790
3791 else
3792 #endif
3793 {
3794 sshift = ((3 - ((row_info->width + 3) & 0x03)) << 1);
3795 dshift = ((3 - ((final_width + 3) & 0x03)) << 1);
3796 s_start = 0;
3797 s_end = 6;
3798 s_inc = 2;
3799 }
3800
3801 for (i = 0; i < row_info->width; i++)
3802 {
3803 png_byte v;
3804 int j;
3805
3806 v = (png_byte)((*sp >> sshift) & 0x03);
3807 for (j = 0; j < jstop; j++)
3808 {
3809 unsigned int tmp = *dp & (0x3f3f >> (6 - dshift));
3810 tmp |= (unsigned int)(v << dshift);
3811 *dp = (png_byte)(tmp & 0xff);
3812
3813 if (dshift == s_end)
3814 {
3815 dshift = s_start;
3816 dp--;
3817 }
3818
3819 else
3820 dshift = (unsigned int)((int)dshift + s_inc);
3821 }
3822
3823 if (sshift == s_end)
3824 {
3825 sshift = s_start;
3826 sp--;
3827 }
3828
3829 else
3830 sshift = (unsigned int)((int)sshift + s_inc);
3831 }
3832 break;
3833 }
3834
3835 case 4:
3836 {
3837 png_bytep sp = row + (png_size_t)((row_info->width - 1) >> 1);
3838 png_bytep dp = row + (png_size_t)((final_width - 1) >> 1);
3839 unsigned int sshift, dshift;
3840 unsigned int s_start, s_end;
3841 int s_inc;
3842 png_uint_32 i;
3843 int jstop = (int)png_pass_inc[pass];
3844
3845 #ifdef PNG_READ_PACKSWAP_SUPPORTED
3846 if ((transformations & PNG_PACKSWAP) != 0)
3847 {
3848 sshift = (((row_info->width + 1) & 0x01) << 2);
3849 dshift = (((final_width + 1) & 0x01) << 2);
3850 s_start = 4;
3851 s_end = 0;
3852 s_inc = -4;
3853 }
3854
3855 else
3856 #endif
3857 {
3858 sshift = ((1 - ((row_info->width + 1) & 0x01)) << 2);
3859 dshift = ((1 - ((final_width + 1) & 0x01)) << 2);
3860 s_start = 0;
3861 s_end = 4;
3862 s_inc = 4;
3863 }
3864
3865 for (i = 0; i < row_info->width; i++)
3866 {
3867 png_byte v = (png_byte)((*sp >> sshift) & 0x0f);
3868 int j;
3869
3870 for (j = 0; j < jstop; j++)
3871 {
3872 unsigned int tmp = *dp & (0xf0f >> (4 - dshift));
3873 tmp |= (unsigned int)(v << dshift);
3874 *dp = (png_byte)(tmp & 0xff);
3875
3876 if (dshift == s_end)
3877 {
3878 dshift = s_start;
3879 dp--;
3880 }
3881
3882 else
3883 dshift = (unsigned int)((int)dshift + s_inc);
3884 }
3885
3886 if (sshift == s_end)
3887 {
3888 sshift = s_start;
3889 sp--;
3890 }
3891
3892 else
3893 sshift = (unsigned int)((int)sshift + s_inc);
3894 }
3895 break;
3896 }
3897
3898 default:
3899 {
3900 png_size_t pixel_bytes = (row_info->pixel_depth >> 3);
3901
3902 png_bytep sp = row + (png_size_t)(row_info->width - 1)
3903 * pixel_bytes;
3904
3905 png_bytep dp = row + (png_size_t)(final_width - 1) * pixel_bytes;
3906
3907 int jstop = (int)png_pass_inc[pass];
3908 png_uint_32 i;
3909
3910 for (i = 0; i < row_info->width; i++)
3911 {
3912 png_byte v[8]; /* SAFE; pixel_depth does not exceed 64 */
3913 int j;
3914
3915 memcpy(v, sp, pixel_bytes);
3916
3917 for (j = 0; j < jstop; j++)
3918 {
3919 memcpy(dp, v, pixel_bytes);
3920 dp -= pixel_bytes;
3921 }
3922
3923 sp -= pixel_bytes;
3924 }
3925 break;
3926 }
3927 }
3928
3929 row_info->width = final_width;
3930 row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, final_width);
3931 }
3932 #ifndef PNG_READ_PACKSWAP_SUPPORTED
3933 PNG_UNUSED(transformations) /* Silence compiler warning */
3934 #endif
3935 }
3936 #endif /* READ_INTERLACING */
3937
3938 static void
3939 png_read_filter_row_sub(png_row_infop row_info, png_bytep row,
3940 png_const_bytep prev_row)
3941 {
3942 png_size_t i;
3943 png_size_t istop = row_info->rowbytes;
3944 unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
3945 png_bytep rp = row + bpp;
3946
3947 PNG_UNUSED(prev_row)
3948
3949 for (i = bpp; i < istop; i++)
3950 {
3951 *rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 0xff);
3952 rp++;
3953 }
3954 }
3955
3956 static void
3957 png_read_filter_row_up(png_row_infop row_info, png_bytep row,
3958 png_const_bytep prev_row)
3959 {
3960 png_size_t i;
3961 png_size_t istop = row_info->rowbytes;
3962 png_bytep rp = row;
3963 png_const_bytep pp = prev_row;
3964
3965 for (i = 0; i < istop; i++)
3966 {
3967 *rp = (png_byte)(((int)(*rp) + (int)(*pp++)) & 0xff);
3968 rp++;
3969 }
3970 }
3971
3972 static void
3973 png_read_filter_row_avg(png_row_infop row_info, png_bytep row,
3974 png_const_bytep prev_row)
3975 {
3976 png_size_t i;
3977 png_bytep rp = row;
3978 png_const_bytep pp = prev_row;
3979 unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
3980 png_size_t istop = row_info->rowbytes - bpp;
3981
3982 for (i = 0; i < bpp; i++)
3983 {
3984 *rp = (png_byte)(((int)(*rp) +
3985 ((int)(*pp++) / 2 )) & 0xff);
3986
3987 rp++;
3988 }
3989
3990 for (i = 0; i < istop; i++)
3991 {
3992 *rp = (png_byte)(((int)(*rp) +
3993 (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff);
3994
3995 rp++;
3996 }
3997 }
3998
3999 static void
4000 png_read_filter_row_paeth_1byte_pixel(png_row_infop row_info, png_bytep row,
4001 png_const_bytep prev_row)
4002 {
4003 png_bytep rp_end = row + row_info->rowbytes;
4004 int a, c;
4005
4006 /* First pixel/byte */
4007 c = *prev_row++;
4008 a = *row + c;
4009 *row++ = (png_byte)a;
4010
4011 /* Remainder */
4012 while (row < rp_end)
4013 {
4014 int b, pa, pb, pc, p;
4015
4016 a &= 0xff; /* From previous iteration or start */
4017 b = *prev_row++;
4018
4019 p = b - c;
4020 pc = a - c;
4021
4022 #ifdef PNG_USE_ABS
4023 pa = abs(p);
4024 pb = abs(pc);
4025 pc = abs(p + pc);
4026 #else
4027 pa = p < 0 ? -p : p;
4028 pb = pc < 0 ? -pc : pc;
4029 pc = (p + pc) < 0 ? -(p + pc) : p + pc;
4030 #endif
4031
4032 /* Find the best predictor, the least of pa, pb, pc favoring the earlier
4033 * ones in the case of a tie.
4034 */
4035 if (pb < pa)
4036 {
4037 pa = pb; a = b;
4038 }
4039 if (pc < pa) a = c;
4040
4041 /* Calculate the current pixel in a, and move the previous row pixel to c
4042 * for the next time round the loop
4043 */
4044 c = b;
4045 a += *row;
4046 *row++ = (png_byte)a;
4047 }
4048 }
4049
4050 static void
4051 png_read_filter_row_paeth_multibyte_pixel(png_row_infop row_info, png_bytep row,
4052 png_const_bytep prev_row)
4053 {
4054 unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
4055 png_bytep rp_end = row + bpp;
4056
4057 /* Process the first pixel in the row completely (this is the same as 'up'
4058 * because there is only one candidate predictor for the first row).
4059 */
4060 while (row < rp_end)
4061 {
4062 int a = *row + *prev_row++;
4063 *row++ = (png_byte)a;
4064 }
4065
4066 /* Remainder */
4067 rp_end = rp_end + (row_info->rowbytes - bpp);
4068
4069 while (row < rp_end)
4070 {
4071 int a, b, c, pa, pb, pc, p;
4072
4073 c = *(prev_row - bpp);
4074 a = *(row - bpp);
4075 b = *prev_row++;
4076
4077 p = b - c;
4078 pc = a - c;
4079
4080 #ifdef PNG_USE_ABS
4081 pa = abs(p);
4082 pb = abs(pc);
4083 pc = abs(p + pc);
4084 #else
4085 pa = p < 0 ? -p : p;
4086 pb = pc < 0 ? -pc : pc;
4087 pc = (p + pc) < 0 ? -(p + pc) : p + pc;
4088 #endif
4089
4090 if (pb < pa)
4091 {
4092 pa = pb; a = b;
4093 }
4094 if (pc < pa) a = c;
4095
4096 a += *row;
4097 *row++ = (png_byte)a;
4098 }
4099 }
4100
4101 static void
4102 png_init_filter_functions(png_structrp pp)
4103 /* This function is called once for every PNG image (except for PNG images
4104 * that only use PNG_FILTER_VALUE_NONE for all rows) to set the
4105 * implementations required to reverse the filtering of PNG rows. Reversing
4106 * the filter is the first transformation performed on the row data. It is
4107 * performed in place, therefore an implementation can be selected based on
4108 * the image pixel format. If the implementation depends on image width then
4109 * take care to ensure that it works correctly if the image is interlaced -
4110 * interlacing causes the actual row width to vary.
4111 */
4112 {
4113 unsigned int bpp = (pp->pixel_depth + 7) >> 3;
4114
4115 pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub;
4116 pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up;
4117 pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg;
4118 if (bpp == 1)
4119 pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
4120 png_read_filter_row_paeth_1byte_pixel;
4121 else
4122 pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
4123 png_read_filter_row_paeth_multibyte_pixel;
4124
4125 #ifdef PNG_FILTER_OPTIMIZATIONS
4126 /* To use this define PNG_FILTER_OPTIMIZATIONS as the name of a function to
4127 * call to install hardware optimizations for the above functions; simply
4128 * replace whatever elements of the pp->read_filter[] array with a hardware
4129 * specific (or, for that matter, generic) optimization.
4130 *
4131 * To see an example of this examine what configure.ac does when
4132 * --enable-arm-neon is specified on the command line.
4133 */
4134 PNG_FILTER_OPTIMIZATIONS(pp, bpp);
4135 #endif
4136 }
4137
4138 void /* PRIVATE */
4139 png_read_filter_row(png_structrp pp, png_row_infop row_info, png_bytep row,
4140 png_const_bytep prev_row, int filter)
4141 {
4142 /* OPTIMIZATION: DO NOT MODIFY THIS FUNCTION, instead #define
4143 * PNG_FILTER_OPTIMIZATIONS to a function that overrides the generic
4144 * implementations. See png_init_filter_functions above.
4145 */
4146 if (filter > PNG_FILTER_VALUE_NONE && filter < PNG_FILTER_VALUE_LAST)
4147 {
4148 if (pp->read_filter[0] == NULL)
4149 png_init_filter_functions(pp);
4150
4151 pp->read_filter[filter-1](row_info, row, prev_row);
4152 }
4153 }
4154
4155 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
4156 void /* PRIVATE */
4157 png_read_IDAT_data(png_structrp png_ptr, png_bytep output,
4158 png_alloc_size_t avail_out)
4159 {
4160 /* Loop reading IDATs and decompressing the result into output[avail_out] */
4161 png_ptr->zstream.next_out = output;
4162 png_ptr->zstream.avail_out = 0; /* safety: set below */
4163
4164 if (output == NULL)
4165 avail_out = 0;
4166
4167 do
4168 {
4169 int ret;
4170 png_byte tmpbuf[PNG_INFLATE_BUF_SIZE];
4171
4172 if (png_ptr->zstream.avail_in == 0)
4173 {
4174 uInt avail_in;
4175 png_bytep buffer;
4176
4177 while (png_ptr->idat_size == 0)
4178 {
4179 png_crc_finish(png_ptr, 0);
4180
4181 png_ptr->idat_size = png_read_chunk_header(png_ptr);
4182 /* This is an error even in the 'check' case because the code just
4183 * consumed a non-IDAT header.
4184 */
4185 if (png_ptr->chunk_name != png_IDAT)
4186 png_error(png_ptr, "Not enough image data");
4187 }
4188
4189 avail_in = png_ptr->IDAT_read_size;
4190
4191 if (avail_in > png_ptr->idat_size)
4192 avail_in = (uInt)png_ptr->idat_size;
4193
4194 /* A PNG with a gradually increasing IDAT size will defeat this attempt
4195 * to minimize memory usage by causing lots of re-allocs, but
4196 * realistically doing IDAT_read_size re-allocs is not likely to be a
4197 * big problem.
4198 */
4199 buffer = png_read_buffer(png_ptr, avail_in, 0/*error*/);
4200
4201 png_crc_read(png_ptr, buffer, avail_in);
4202 png_ptr->idat_size -= avail_in;
4203
4204 png_ptr->zstream.next_in = buffer;
4205 png_ptr->zstream.avail_in = avail_in;
4206 }
4207
4208 /* And set up the output side. */
4209 if (output != NULL) /* standard read */
4210 {
4211 uInt out = ZLIB_IO_MAX;
4212
4213 if (out > avail_out)
4214 out = (uInt)avail_out;
4215
4216 avail_out -= out;
4217 png_ptr->zstream.avail_out = out;
4218 }
4219
4220 else /* after last row, checking for end */
4221 {
4222 png_ptr->zstream.next_out = tmpbuf;
4223 png_ptr->zstream.avail_out = (sizeof tmpbuf);
4224 }
4225
4226 /* Use NO_FLUSH; this gives zlib the maximum opportunity to optimize the
4227 * process. If the LZ stream is truncated the sequential reader will
4228 * terminally damage the stream, above, by reading the chunk header of the
4229 * following chunk (it then exits with png_error).
4230 *
4231 * TODO: deal more elegantly with truncated IDAT lists.
4232 */
4233 ret = PNG_INFLATE(png_ptr, Z_NO_FLUSH);
4234
4235 /* Take the unconsumed output back. */
4236 if (output != NULL)
4237 avail_out += png_ptr->zstream.avail_out;
4238
4239 else /* avail_out counts the extra bytes */
4240 avail_out += (sizeof tmpbuf) - png_ptr->zstream.avail_out;
4241
4242 png_ptr->zstream.avail_out = 0;
4243
4244 if (ret == Z_STREAM_END)
4245 {
4246 /* Do this for safety; we won't read any more into this row. */
4247 png_ptr->zstream.next_out = NULL;
4248
4249 png_ptr->mode |= PNG_AFTER_IDAT;
4250 png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
4251
4252 if (png_ptr->zstream.avail_in > 0 || png_ptr->idat_size > 0)
4253 png_chunk_benign_error(png_ptr, "Extra compressed data");
4254 break;
4255 }
4256
4257 if (ret != Z_OK)
4258 {
4259 png_zstream_error(png_ptr, ret);
4260
4261 if (output != NULL)
4262 png_chunk_error(png_ptr, png_ptr->zstream.msg);
4263
4264 else /* checking */
4265 {
4266 png_chunk_benign_error(png_ptr, png_ptr->zstream.msg);
4267 return;
4268 }
4269 }
4270 } while (avail_out > 0);
4271
4272 if (avail_out > 0)
4273 {
4274 /* The stream ended before the image; this is the same as too few IDATs so
4275 * should be handled the same way.
4276 */
4277 if (output != NULL)
4278 png_error(png_ptr, "Not enough image data");
4279
4280 else /* the deflate stream contained extra data */
4281 png_chunk_benign_error(png_ptr, "Too much image data");
4282 }
4283 }
4284
4285 void /* PRIVATE */
4286 png_read_finish_IDAT(png_structrp png_ptr)
4287 {
4288 /* We don't need any more data and the stream should have ended, however the
4289 * LZ end code may actually not have been processed. In this case we must
4290 * read it otherwise stray unread IDAT data or, more likely, an IDAT chunk
4291 * may still remain to be consumed.
4292 */
4293 if ((png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0)
4294 {
4295 /* The NULL causes png_read_IDAT_data to swallow any remaining bytes in
4296 * the compressed stream, but the stream may be damaged too, so even after
4297 * this call we may need to terminate the zstream ownership.
4298 */
4299 png_read_IDAT_data(png_ptr, NULL, 0);
4300 png_ptr->zstream.next_out = NULL; /* safety */
4301
4302 /* Now clear everything out for safety; the following may not have been
4303 * done.
4304 */
4305 if ((png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0)
4306 {
4307 png_ptr->mode |= PNG_AFTER_IDAT;
4308 png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
4309 }
4310 }
4311
4312 /* If the zstream has not been released do it now *and* terminate the reading
4313 * of the final IDAT chunk.
4314 */
4315 if (png_ptr->zowner == png_IDAT)
4316 {
4317 /* Always do this; the pointers otherwise point into the read buffer. */
4318 png_ptr->zstream.next_in = NULL;
4319 png_ptr->zstream.avail_in = 0;
4320
4321 /* Now we no longer own the zstream. */
4322 png_ptr->zowner = 0;
4323
4324 /* The slightly weird semantics of the sequential IDAT reading is that we
4325 * are always in or at the end of an IDAT chunk, so we always need to do a
4326 * crc_finish here. If idat_size is non-zero we also need to read the
4327 * spurious bytes at the end of the chunk now.
4328 */
4329 (void)png_crc_finish(png_ptr, png_ptr->idat_size);
4330 }
4331 }
4332
4333 void /* PRIVATE */
4334 png_read_finish_row(png_structrp png_ptr)
4335 {
4336 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
4337
4338 /* Start of interlace block */
4339 static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
4340
4341 /* Offset to next interlace block */
4342 static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
4343
4344 /* Start of interlace block in the y direction */
4345 static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
4346
4347 /* Offset to next interlace block in the y direction */
4348 static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
4349
4350 png_debug(1, "in png_read_finish_row");
4351 png_ptr->row_number++;
4352 if (png_ptr->row_number < png_ptr->num_rows)
4353 return;
4354
4355 if (png_ptr->interlaced != 0)
4356 {
4357 png_ptr->row_number = 0;
4358
4359 /* TO DO: don't do this if prev_row isn't needed (requires
4360 * read-ahead of the next row's filter byte.
4361 */
4362 memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
4363
4364 do
4365 {
4366 png_ptr->pass++;
4367
4368 if (png_ptr->pass >= 7)
4369 break;
4370
4371 png_ptr->iwidth = (png_ptr->width +
4372 png_pass_inc[png_ptr->pass] - 1 -
4373 png_pass_start[png_ptr->pass]) /
4374 png_pass_inc[png_ptr->pass];
4375
4376 if ((png_ptr->transformations & PNG_INTERLACE) == 0)
4377 {
4378 png_ptr->num_rows = (png_ptr->height +
4379 png_pass_yinc[png_ptr->pass] - 1 -
4380 png_pass_ystart[png_ptr->pass]) /
4381 png_pass_yinc[png_ptr->pass];
4382 }
4383
4384 else /* if (png_ptr->transformations & PNG_INTERLACE) */
4385 break; /* libpng deinterlacing sees every row */
4386
4387 } while (png_ptr->num_rows == 0 || png_ptr->iwidth == 0);
4388
4389 if (png_ptr->pass < 7)
4390 return;
4391 }
4392
4393 /* Here after at the end of the last row of the last pass. */
4394 png_read_finish_IDAT(png_ptr);
4395 }
4396 #endif /* SEQUENTIAL_READ */
4397
4398 void /* PRIVATE */
4399 png_read_start_row(png_structrp png_ptr)
4400 {
4401 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
4402
4403 /* Start of interlace block */
4404 static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
4405
4406 /* Offset to next interlace block */
4407 static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
4408
4409 /* Start of interlace block in the y direction */
4410 static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
4411
4412 /* Offset to next interlace block in the y direction */
4413 static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
4414
4415 unsigned int max_pixel_depth;
4416 png_size_t row_bytes;
4417
4418 png_debug(1, "in png_read_start_row");
4419
4420 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
4421 png_init_read_transformations(png_ptr);
4422 #endif
4423 if (png_ptr->interlaced != 0)
4424 {
4425 if ((png_ptr->transformations & PNG_INTERLACE) == 0)
4426 png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 -
4427 png_pass_ystart[0]) / png_pass_yinc[0];
4428
4429 else
4430 png_ptr->num_rows = png_ptr->height;
4431
4432 png_ptr->iwidth = (png_ptr->width +
4433 png_pass_inc[png_ptr->pass] - 1 -
4434 png_pass_start[png_ptr->pass]) /
4435 png_pass_inc[png_ptr->pass];
4436 }
4437
4438 else
4439 {
4440 png_ptr->num_rows = png_ptr->height;
4441 png_ptr->iwidth = png_ptr->width;
4442 }
4443
4444 max_pixel_depth = (unsigned int)png_ptr->pixel_depth;
4445
4446 /* WARNING: * png_read_transform_info (pngrtran.c) performs a simpler set of
4447 * calculations to calculate the final pixel depth, then
4448 * png_do_read_transforms actually does the transforms. This means that the
4449 * code which effectively calculates this value is actually repeated in three
4450 * separate places. They must all match. Innocent changes to the order of
4451 * transformations can and will break libpng in a way that causes memory
4452 * overwrites.
4453 *
4454 * TODO: fix this.
4455 */
4456 #ifdef PNG_READ_PACK_SUPPORTED
4457 if ((png_ptr->transformations & PNG_PACK) != 0 && png_ptr->bit_depth < 8)
4458 max_pixel_depth = 8;
4459 #endif
4460
4461 #ifdef PNG_READ_EXPAND_SUPPORTED
4462 if ((png_ptr->transformations & PNG_EXPAND) != 0)
4463 {
4464 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
4465 {
4466 if (png_ptr->num_trans != 0)
4467 max_pixel_depth = 32;
4468
4469 else
4470 max_pixel_depth = 24;
4471 }
4472
4473 else if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
4474 {
4475 if (max_pixel_depth < 8)
4476 max_pixel_depth = 8;
4477
4478 if (png_ptr->num_trans != 0)
4479 max_pixel_depth *= 2;
4480 }
4481
4482 else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
4483 {
4484 if (png_ptr->num_trans != 0)
4485 {
4486 max_pixel_depth *= 4;
4487 max_pixel_depth /= 3;
4488 }
4489 }
4490 }
4491 #endif
4492
4493 #ifdef PNG_READ_EXPAND_16_SUPPORTED
4494 if ((png_ptr->transformations & PNG_EXPAND_16) != 0)
4495 {
4496 # ifdef PNG_READ_EXPAND_SUPPORTED
4497 /* In fact it is an error if it isn't supported, but checking is
4498 * the safe way.
4499 */
4500 if ((png_ptr->transformations & PNG_EXPAND) != 0)
4501 {
4502 if (png_ptr->bit_depth < 16)
4503 max_pixel_depth *= 2;
4504 }
4505 else
4506 # endif
4507 png_ptr->transformations &= ~PNG_EXPAND_16;
4508 }
4509 #endif
4510
4511 #ifdef PNG_READ_FILLER_SUPPORTED
4512 if ((png_ptr->transformations & (PNG_FILLER)) != 0)
4513 {
4514 if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
4515 {
4516 if (max_pixel_depth <= 8)
4517 max_pixel_depth = 16;
4518
4519 else
4520 max_pixel_depth = 32;
4521 }
4522
4523 else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB ||
4524 png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
4525 {
4526 if (max_pixel_depth <= 32)
4527 max_pixel_depth = 32;
4528
4529 else
4530 max_pixel_depth = 64;
4531 }
4532 }
4533 #endif
4534
4535 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
4536 if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0)
4537 {
4538 if (
4539 #ifdef PNG_READ_EXPAND_SUPPORTED
4540 (png_ptr->num_trans != 0 &&
4541 (png_ptr->transformations & PNG_EXPAND) != 0) ||
4542 #endif
4543 #ifdef PNG_READ_FILLER_SUPPORTED
4544 (png_ptr->transformations & (PNG_FILLER)) != 0 ||
4545 #endif
4546 png_ptr->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
4547 {
4548 if (max_pixel_depth <= 16)
4549 max_pixel_depth = 32;
4550
4551 else
4552 max_pixel_depth = 64;
4553 }
4554
4555 else
4556 {
4557 if (max_pixel_depth <= 8)
4558 {
4559 if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
4560 max_pixel_depth = 32;
4561
4562 else
4563 max_pixel_depth = 24;
4564 }
4565
4566 else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
4567 max_pixel_depth = 64;
4568
4569 else
4570 max_pixel_depth = 48;
4571 }
4572 }
4573 #endif
4574
4575 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) && \
4576 defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
4577 if ((png_ptr->transformations & PNG_USER_TRANSFORM) != 0)
4578 {
4579 unsigned int user_pixel_depth = png_ptr->user_transform_depth *
4580 png_ptr->user_transform_channels;
4581
4582 if (user_pixel_depth > max_pixel_depth)
4583 max_pixel_depth = user_pixel_depth;
4584 }
4585 #endif
4586
4587 /* This value is stored in png_struct and double checked in the row read
4588 * code.
4589 */
4590 png_ptr->maximum_pixel_depth = (png_byte)max_pixel_depth;
4591 png_ptr->transformed_pixel_depth = 0; /* calculated on demand */
4592
4593 /* Align the width on the next larger 8 pixels. Mainly used
4594 * for interlacing
4595 */
4596 row_bytes = ((png_ptr->width + 7) & ~((png_uint_32)7));
4597 /* Calculate the maximum bytes needed, adding a byte and a pixel
4598 * for safety's sake
4599 */
4600 row_bytes = PNG_ROWBYTES(max_pixel_depth, row_bytes) +
4601 1 + ((max_pixel_depth + 7) >> 3U);
4602
4603 #ifdef PNG_MAX_MALLOC_64K
4604 if (row_bytes > (png_uint_32)65536L)
4605 png_error(png_ptr, "This image requires a row greater than 64KB");
4606 #endif
4607
4608 if (row_bytes + 48 > png_ptr->old_big_row_buf_size)
4609 {
4610 png_free(png_ptr, png_ptr->big_row_buf);
4611 png_free(png_ptr, png_ptr->big_prev_row);
4612
4613 if (png_ptr->interlaced != 0)
4614 png_ptr->big_row_buf = (png_bytep)png_calloc(png_ptr,
4615 row_bytes + 48);
4616
4617 else
4618 png_ptr->big_row_buf = (png_bytep)png_malloc(png_ptr, row_bytes + 48);
4619
4620 png_ptr->big_prev_row = (png_bytep)png_malloc(png_ptr, row_bytes + 48);
4621
4622 #ifdef PNG_ALIGNED_MEMORY_SUPPORTED
4623 /* Use 16-byte aligned memory for row_buf with at least 16 bytes
4624 * of padding before and after row_buf; treat prev_row similarly.
4625 * NOTE: the alignment is to the start of the pixels, one beyond the start
4626 * of the buffer, because of the filter byte. Prior to libpng 1.5.6 this
4627 * was incorrect; the filter byte was aligned, which had the exact
4628 * opposite effect of that intended.
4629 */
4630 {
4631 png_bytep temp = png_ptr->big_row_buf + 32;
4632 int extra = (int)((temp - (png_bytep)0) & 0x0f);
4633 png_ptr->row_buf = temp - extra - 1/*filter byte*/;
4634
4635 temp = png_ptr->big_prev_row + 32;
4636 extra = (int)((temp - (png_bytep)0) & 0x0f);
4637 png_ptr->prev_row = temp - extra - 1/*filter byte*/;
4638 }
4639
4640 #else
4641 /* Use 31 bytes of padding before and 17 bytes after row_buf. */
4642 png_ptr->row_buf = png_ptr->big_row_buf + 31;
4643 png_ptr->prev_row = png_ptr->big_prev_row + 31;
4644 #endif
4645 png_ptr->old_big_row_buf_size = row_bytes + 48;
4646 }
4647
4648 #ifdef PNG_MAX_MALLOC_64K
4649 if (png_ptr->rowbytes > 65535)
4650 png_error(png_ptr, "This image requires a row greater than 64KB");
4651
4652 #endif
4653 if (png_ptr->rowbytes > (PNG_SIZE_MAX - 1))
4654 png_error(png_ptr, "Row has too many bytes to allocate in memory");
4655
4656 memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
4657
4658 png_debug1(3, "width = %u,", png_ptr->width);
4659 png_debug1(3, "height = %u,", png_ptr->height);
4660 png_debug1(3, "iwidth = %u,", png_ptr->iwidth);
4661 png_debug1(3, "num_rows = %u,", png_ptr->num_rows);
4662 png_debug1(3, "rowbytes = %lu,", (unsigned long)png_ptr->rowbytes);
4663 png_debug1(3, "irowbytes = %lu",
4664 (unsigned long)PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->iwidth) + 1);
4665
4666 /* The sequential reader needs a buffer for IDAT, but the progressive reader
4667 * does not, so free the read buffer now regardless; the sequential reader
4668 * reallocates it on demand.
4669 */
4670 if (png_ptr->read_buffer != NULL)
4671 {
4672 png_bytep buffer = png_ptr->read_buffer;
4673
4674 png_ptr->read_buffer_size = 0;
4675 png_ptr->read_buffer = NULL;
4676 png_free(png_ptr, buffer);
4677 }
4678
4679 /* Finally claim the zstream for the inflate of the IDAT data, use the bits
4680 * value from the stream (note that this will result in a fatal error if the
4681 * IDAT stream has a bogus deflate header window_bits value, but this should
4682 * not be happening any longer!)
4683 */
4684 if (png_inflate_claim(png_ptr, png_IDAT) != Z_OK)
4685 png_error(png_ptr, png_ptr->zstream.msg);
4686
4687 png_ptr->flags |= PNG_FLAG_ROW_INIT;
4688 }
4689 #endif /* READ */