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 * Copyright (c) 2018 Cosmin Truta
33 * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
34 * Copyright (c) 1996-1997 Andreas Dilger
35 * 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 accommodate 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 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 png_uint_32 profile_length = png_get_uint_32(profile_header);
1493
1494 if (png_icc_check_length(png_ptr, &png_ptr->colorspace,
1495 keyword, profile_length) != 0)
1496 {
1497 /* The length is apparently ok, so we can check the 132
1498 * byte header.
1499 */
1500 if (png_icc_check_header(png_ptr, &png_ptr->colorspace,
1501 keyword, profile_length, profile_header,
1502 png_ptr->color_type) != 0)
1503 {
1504 /* Now read the tag table; a variable size buffer is
1505 * needed at this point, allocate one for the whole
1506 * profile. The header check has already validated
1507 * that none of this stuff will overflow.
1508 */
1509 png_uint_32 tag_count =
1510 png_get_uint_32(profile_header + 128);
1511 png_bytep profile = png_read_buffer(png_ptr,
1512 profile_length, 2/*silent*/);
1513
1514 if (profile != NULL)
1515 {
1516 memcpy(profile, profile_header,
1517 (sizeof profile_header));
1518
1519 size = 12 * tag_count;
1520
1521 (void)png_inflate_read(png_ptr, local_buffer,
1522 (sizeof local_buffer), &length,
1523 profile + (sizeof profile_header), &size, 0);
1524
1525 /* Still expect a buffer error because we expect
1526 * there to be some tag data!
1527 */
1528 if (size == 0)
1529 {
1530 if (png_icc_check_tag_table(png_ptr,
1531 &png_ptr->colorspace, keyword, profile_length,
1532 profile) != 0)
1533 {
1534 /* The profile has been validated for basic
1535 * security issues, so read the whole thing in.
1536 */
1537 size = profile_length - (sizeof profile_header)
1538 - 12 * tag_count;
1539
1540 (void)png_inflate_read(png_ptr, local_buffer,
1541 (sizeof local_buffer), &length,
1542 profile + (sizeof profile_header) +
1543 12 * tag_count, &size, 1/*finish*/);
1544
1545 if (length > 0 && !(png_ptr->flags &
1546 PNG_FLAG_BENIGN_ERRORS_WARN))
1547 errmsg = "extra compressed data";
1548
1549 /* But otherwise allow extra data: */
1550 else if (size == 0)
1551 {
1552 if (length > 0)
1553 {
1554 /* This can be handled completely, so
1555 * keep going.
1556 */
1557 png_chunk_warning(png_ptr,
1558 "extra compressed data");
1559 }
1560
1561 png_crc_finish(png_ptr, length);
1562 finished = 1;
1563
1564 # if defined(PNG_sRGB_SUPPORTED) && PNG_sRGB_PROFILE_CHECKS >= 0
1565 /* Check for a match against sRGB */
1566 png_icc_set_sRGB(png_ptr,
1567 &png_ptr->colorspace, profile,
1568 png_ptr->zstream.adler);
1569 # endif
1570
1571 /* Steal the profile for info_ptr. */
1572 if (info_ptr != NULL)
1573 {
1574 png_free_data(png_ptr, info_ptr,
1575 PNG_FREE_ICCP, 0);
1576
1577 info_ptr->iccp_name = png_voidcast(char*,
1578 png_malloc_base(png_ptr,
1579 keyword_length+1));
1580 if (info_ptr->iccp_name != NULL)
1581 {
1582 memcpy(info_ptr->iccp_name, keyword,
1583 keyword_length+1);
1584 info_ptr->iccp_proflen =
1585 profile_length;
1586 info_ptr->iccp_profile = profile;
1587 png_ptr->read_buffer = NULL; /*steal*/
1588 info_ptr->free_me |= PNG_FREE_ICCP;
1589 info_ptr->valid |= PNG_INFO_iCCP;
1590 }
1591
1592 else
1593 {
1594 png_ptr->colorspace.flags |=
1595 PNG_COLORSPACE_INVALID;
1596 errmsg = "out of memory";
1597 }
1598 }
1599
1600 /* else the profile remains in the read
1601 * buffer which gets reused for subsequent
1602 * chunks.
1603 */
1604
1605 if (info_ptr != NULL)
1606 png_colorspace_sync(png_ptr, info_ptr);
1607
1608 if (errmsg == NULL)
1609 {
1610 png_ptr->zowner = 0;
1611 return;
1612 }
1613 }
1614 if (errmsg == NULL)
1615 errmsg = png_ptr->zstream.msg;
1616 }
1617 /* else png_icc_check_tag_table output an error */
1618 }
1619 else /* profile truncated */
1620 errmsg = png_ptr->zstream.msg;
1621 }
1622
1623 else
1624 errmsg = "out of memory";
1625 }
1626
1627 /* else png_icc_check_header output an error */
1628 }
1629
1630 /* else png_icc_check_length output an error */
1631 }
1632
1633 else /* profile truncated */
1634 errmsg = png_ptr->zstream.msg;
1635
1636 /* Release the stream */
1637 png_ptr->zowner = 0;
1638 }
1639
1640 else /* png_inflate_claim failed */
1641 errmsg = png_ptr->zstream.msg;
1642 }
1643
1644 else
1645 errmsg = "bad compression method"; /* or missing */
1646 }
1647
1648 else
1649 errmsg = "bad keyword";
1650 }
1651
1652 else
1653 errmsg = "too many profiles";
1654
1655 /* Failure: the reason is in 'errmsg' */
1656 if (finished == 0)
1657 png_crc_finish(png_ptr, length);
1658
1659 png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID;
1660 png_colorspace_sync(png_ptr, info_ptr);
1661 if (errmsg != NULL) /* else already output */
1662 png_chunk_benign_error(png_ptr, errmsg);
1663 }
1664 #endif /* READ_iCCP */
1665
1666 #ifdef PNG_READ_sPLT_SUPPORTED
1667 void /* PRIVATE */
1668 png_handle_sPLT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1669 /* Note: this does not properly handle chunks that are > 64K under DOS */
1670 {
1671 png_bytep entry_start, buffer;
1672 png_sPLT_t new_palette;
1673 png_sPLT_entryp pp;
1674 png_uint_32 data_length;
1675 int entry_size, i;
1676 png_uint_32 skip = 0;
1677 png_uint_32 dl;
1678 size_t max_dl;
1679
1680 png_debug(1, "in png_handle_sPLT");
1681
1682 #ifdef PNG_USER_LIMITS_SUPPORTED
1683 if (png_ptr->user_chunk_cache_max != 0)
1684 {
1685 if (png_ptr->user_chunk_cache_max == 1)
1686 {
1687 png_crc_finish(png_ptr, length);
1688 return;
1689 }
1690
1691 if (--png_ptr->user_chunk_cache_max == 1)
1692 {
1693 png_warning(png_ptr, "No space in chunk cache for sPLT");
1694 png_crc_finish(png_ptr, length);
1695 return;
1696 }
1697 }
1698 #endif
1699
1700 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1701 png_chunk_error(png_ptr, "missing IHDR");
1702
1703 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
1704 {
1705 png_crc_finish(png_ptr, length);
1706 png_chunk_benign_error(png_ptr, "out of place");
1707 return;
1708 }
1709
1710 #ifdef PNG_MAX_MALLOC_64K
1711 if (length > 65535U)
1712 {
1713 png_crc_finish(png_ptr, length);
1714 png_chunk_benign_error(png_ptr, "too large to fit in memory");
1715 return;
1716 }
1717 #endif
1718
1719 buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/);
1720 if (buffer == NULL)
1721 {
1722 png_crc_finish(png_ptr, length);
1723 png_chunk_benign_error(png_ptr, "out of memory");
1724 return;
1725 }
1726
1727
1728 /* WARNING: this may break if size_t is less than 32 bits; it is assumed
1729 * that the PNG_MAX_MALLOC_64K test is enabled in this case, but this is a
1730 * potential breakage point if the types in pngconf.h aren't exactly right.
1731 */
1732 png_crc_read(png_ptr, buffer, length);
1733
1734 if (png_crc_finish(png_ptr, skip) != 0)
1735 return;
1736
1737 buffer[length] = 0;
1738
1739 for (entry_start = buffer; *entry_start; entry_start++)
1740 /* Empty loop to find end of name */ ;
1741
1742 ++entry_start;
1743
1744 /* A sample depth should follow the separator, and we should be on it */
1745 if (length < 2U || entry_start > buffer + (length - 2U))
1746 {
1747 png_warning(png_ptr, "malformed sPLT chunk");
1748 return;
1749 }
1750
1751 new_palette.depth = *entry_start++;
1752 entry_size = (new_palette.depth == 8 ? 6 : 10);
1753 /* This must fit in a png_uint_32 because it is derived from the original
1754 * chunk data length.
1755 */
1756 data_length = length - (png_uint_32)(entry_start - buffer);
1757
1758 /* Integrity-check the data length */
1759 if ((data_length % (unsigned int)entry_size) != 0)
1760 {
1761 png_warning(png_ptr, "sPLT chunk has bad length");
1762 return;
1763 }
1764
1765 dl = (png_uint_32)(data_length / (unsigned int)entry_size);
1766 max_dl = PNG_SIZE_MAX / (sizeof (png_sPLT_entry));
1767
1768 if (dl > max_dl)
1769 {
1770 png_warning(png_ptr, "sPLT chunk too long");
1771 return;
1772 }
1773
1774 new_palette.nentries = (png_int_32)(data_length / (unsigned int)entry_size);
1775
1776 new_palette.entries = (png_sPLT_entryp)png_malloc_warn(png_ptr,
1777 (png_alloc_size_t) new_palette.nentries * (sizeof (png_sPLT_entry)));
1778
1779 if (new_palette.entries == NULL)
1780 {
1781 png_warning(png_ptr, "sPLT chunk requires too much memory");
1782 return;
1783 }
1784
1785 #ifdef PNG_POINTER_INDEXING_SUPPORTED
1786 for (i = 0; i < new_palette.nentries; i++)
1787 {
1788 pp = new_palette.entries + i;
1789
1790 if (new_palette.depth == 8)
1791 {
1792 pp->red = *entry_start++;
1793 pp->green = *entry_start++;
1794 pp->blue = *entry_start++;
1795 pp->alpha = *entry_start++;
1796 }
1797
1798 else
1799 {
1800 pp->red = png_get_uint_16(entry_start); entry_start += 2;
1801 pp->green = png_get_uint_16(entry_start); entry_start += 2;
1802 pp->blue = png_get_uint_16(entry_start); entry_start += 2;
1803 pp->alpha = png_get_uint_16(entry_start); entry_start += 2;
1804 }
1805
1806 pp->frequency = png_get_uint_16(entry_start); entry_start += 2;
1807 }
1808 #else
1809 pp = new_palette.entries;
1810
1811 for (i = 0; i < new_palette.nentries; i++)
1812 {
1813
1814 if (new_palette.depth == 8)
1815 {
1816 pp[i].red = *entry_start++;
1817 pp[i].green = *entry_start++;
1818 pp[i].blue = *entry_start++;
1819 pp[i].alpha = *entry_start++;
1820 }
1821
1822 else
1823 {
1824 pp[i].red = png_get_uint_16(entry_start); entry_start += 2;
1825 pp[i].green = png_get_uint_16(entry_start); entry_start += 2;
1826 pp[i].blue = png_get_uint_16(entry_start); entry_start += 2;
1827 pp[i].alpha = png_get_uint_16(entry_start); entry_start += 2;
1828 }
1829
1830 pp[i].frequency = png_get_uint_16(entry_start); entry_start += 2;
1831 }
1832 #endif
1833
1834 /* Discard all chunk data except the name and stash that */
1835 new_palette.name = (png_charp)buffer;
1836
1837 png_set_sPLT(png_ptr, info_ptr, &new_palette, 1);
1838
1839 png_free(png_ptr, new_palette.entries);
1840 }
1841 #endif /* READ_sPLT */
1842
1843 #ifdef PNG_READ_tRNS_SUPPORTED
1844 void /* PRIVATE */
1845 png_handle_tRNS(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1846 {
1847 png_byte readbuf[PNG_MAX_PALETTE_LENGTH];
1848
1849 png_debug(1, "in png_handle_tRNS");
1850
1851 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1852 png_chunk_error(png_ptr, "missing IHDR");
1853
1854 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
1855 {
1856 png_crc_finish(png_ptr, length);
1857 png_chunk_benign_error(png_ptr, "out of place");
1858 return;
1859 }
1860
1861 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS) != 0)
1862 {
1863 png_crc_finish(png_ptr, length);
1864 png_chunk_benign_error(png_ptr, "duplicate");
1865 return;
1866 }
1867
1868 if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
1869 {
1870 png_byte buf[2];
1871
1872 if (length != 2)
1873 {
1874 png_crc_finish(png_ptr, length);
1875 png_chunk_benign_error(png_ptr, "invalid");
1876 return;
1877 }
1878
1879 png_crc_read(png_ptr, buf, 2);
1880 png_ptr->num_trans = 1;
1881 png_ptr->trans_color.gray = png_get_uint_16(buf);
1882 }
1883
1884 else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
1885 {
1886 png_byte buf[6];
1887
1888 if (length != 6)
1889 {
1890 png_crc_finish(png_ptr, length);
1891 png_chunk_benign_error(png_ptr, "invalid");
1892 return;
1893 }
1894
1895 png_crc_read(png_ptr, buf, length);
1896 png_ptr->num_trans = 1;
1897 png_ptr->trans_color.red = png_get_uint_16(buf);
1898 png_ptr->trans_color.green = png_get_uint_16(buf + 2);
1899 png_ptr->trans_color.blue = png_get_uint_16(buf + 4);
1900 }
1901
1902 else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1903 {
1904 if ((png_ptr->mode & PNG_HAVE_PLTE) == 0)
1905 {
1906 /* TODO: is this actually an error in the ISO spec? */
1907 png_crc_finish(png_ptr, length);
1908 png_chunk_benign_error(png_ptr, "out of place");
1909 return;
1910 }
1911
1912 if (length > (unsigned int) png_ptr->num_palette ||
1913 length > (unsigned int) PNG_MAX_PALETTE_LENGTH ||
1914 length == 0)
1915 {
1916 png_crc_finish(png_ptr, length);
1917 png_chunk_benign_error(png_ptr, "invalid");
1918 return;
1919 }
1920
1921 png_crc_read(png_ptr, readbuf, length);
1922 png_ptr->num_trans = (png_uint_16)length;
1923 }
1924
1925 else
1926 {
1927 png_crc_finish(png_ptr, length);
1928 png_chunk_benign_error(png_ptr, "invalid with alpha channel");
1929 return;
1930 }
1931
1932 if (png_crc_finish(png_ptr, 0) != 0)
1933 {
1934 png_ptr->num_trans = 0;
1935 return;
1936 }
1937
1938 /* TODO: this is a horrible side effect in the palette case because the
1939 * png_struct ends up with a pointer to the tRNS buffer owned by the
1940 * png_info. Fix this.
1941 */
1942 png_set_tRNS(png_ptr, info_ptr, readbuf, png_ptr->num_trans,
1943 &(png_ptr->trans_color));
1944 }
1945 #endif
1946
1947 #ifdef PNG_READ_bKGD_SUPPORTED
1948 void /* PRIVATE */
1949 png_handle_bKGD(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1950 {
1951 unsigned int truelen;
1952 png_byte buf[6];
1953 png_color_16 background;
1954
1955 png_debug(1, "in png_handle_bKGD");
1956
1957 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1958 png_chunk_error(png_ptr, "missing IHDR");
1959
1960 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0 ||
1961 (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
1962 (png_ptr->mode & PNG_HAVE_PLTE) == 0))
1963 {
1964 png_crc_finish(png_ptr, length);
1965 png_chunk_benign_error(png_ptr, "out of place");
1966 return;
1967 }
1968
1969 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD) != 0)
1970 {
1971 png_crc_finish(png_ptr, length);
1972 png_chunk_benign_error(png_ptr, "duplicate");
1973 return;
1974 }
1975
1976 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1977 truelen = 1;
1978
1979 else if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
1980 truelen = 6;
1981
1982 else
1983 truelen = 2;
1984
1985 if (length != truelen)
1986 {
1987 png_crc_finish(png_ptr, length);
1988 png_chunk_benign_error(png_ptr, "invalid");
1989 return;
1990 }
1991
1992 png_crc_read(png_ptr, buf, truelen);
1993
1994 if (png_crc_finish(png_ptr, 0) != 0)
1995 return;
1996
1997 /* We convert the index value into RGB components so that we can allow
1998 * arbitrary RGB values for background when we have transparency, and
1999 * so it is easy to determine the RGB values of the background color
2000 * from the info_ptr struct.
2001 */
2002 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
2003 {
2004 background.index = buf[0];
2005
2006 if (info_ptr != NULL && info_ptr->num_palette != 0)
2007 {
2008 if (buf[0] >= info_ptr->num_palette)
2009 {
2010 png_chunk_benign_error(png_ptr, "invalid index");
2011 return;
2012 }
2013
2014 background.red = (png_uint_16)png_ptr->palette[buf[0]].red;
2015 background.green = (png_uint_16)png_ptr->palette[buf[0]].green;
2016 background.blue = (png_uint_16)png_ptr->palette[buf[0]].blue;
2017 }
2018
2019 else
2020 background.red = background.green = background.blue = 0;
2021
2022 background.gray = 0;
2023 }
2024
2025 else if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0) /* GRAY */
2026 {
2027 if (png_ptr->bit_depth <= 8)
2028 {
2029 if (buf[0] != 0 || buf[1] >= (unsigned int)(1 << png_ptr->bit_depth))
2030 {
2031 png_chunk_benign_error(png_ptr, "invalid gray level");
2032 return;
2033 }
2034 }
2035
2036 background.index = 0;
2037 background.red =
2038 background.green =
2039 background.blue =
2040 background.gray = png_get_uint_16(buf);
2041 }
2042
2043 else
2044 {
2045 if (png_ptr->bit_depth <= 8)
2046 {
2047 if (buf[0] != 0 || buf[2] != 0 || buf[4] != 0)
2048 {
2049 png_chunk_benign_error(png_ptr, "invalid color");
2050 return;
2051 }
2052 }
2053
2054 background.index = 0;
2055 background.red = png_get_uint_16(buf);
2056 background.green = png_get_uint_16(buf + 2);
2057 background.blue = png_get_uint_16(buf + 4);
2058 background.gray = 0;
2059 }
2060
2061 png_set_bKGD(png_ptr, info_ptr, &background);
2062 }
2063 #endif
2064
2065 #ifdef PNG_READ_eXIf_SUPPORTED
2066 void /* PRIVATE */
2067 png_handle_eXIf(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2068 {
2069 unsigned int i;
2070
2071 png_debug(1, "in png_handle_eXIf");
2072
2073 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2074 png_chunk_error(png_ptr, "missing IHDR");
2075
2076 if (length < 2)
2077 {
2078 png_crc_finish(png_ptr, length);
2079 png_chunk_benign_error(png_ptr, "too short");
2080 return;
2081 }
2082
2083 else if (info_ptr == NULL || (info_ptr->valid & PNG_INFO_eXIf) != 0)
2084 {
2085 png_crc_finish(png_ptr, length);
2086 png_chunk_benign_error(png_ptr, "duplicate");
2087 return;
2088 }
2089
2090 info_ptr->free_me |= PNG_FREE_EXIF;
2091
2092 info_ptr->eXIf_buf = png_voidcast(png_bytep,
2093 png_malloc_warn(png_ptr, length));
2094
2095 if (info_ptr->eXIf_buf == NULL)
2096 {
2097 png_crc_finish(png_ptr, length);
2098 png_chunk_benign_error(png_ptr, "out of memory");
2099 return;
2100 }
2101
2102 for (i = 0; i < length; i++)
2103 {
2104 png_byte buf[1];
2105 png_crc_read(png_ptr, buf, 1);
2106 info_ptr->eXIf_buf[i] = buf[0];
2107 if (i == 1 && buf[0] != 'M' && buf[0] != 'I'
2108 && info_ptr->eXIf_buf[0] != buf[0])
2109 {
2110 png_crc_finish(png_ptr, length);
2111 png_chunk_benign_error(png_ptr, "incorrect byte-order specifier");
2112 png_free(png_ptr, info_ptr->eXIf_buf);
2113 info_ptr->eXIf_buf = NULL;
2114 return;
2115 }
2116 }
2117
2118 if (png_crc_finish(png_ptr, 0) != 0)
2119 return;
2120
2121 png_set_eXIf_1(png_ptr, info_ptr, length, info_ptr->eXIf_buf);
2122
2123 png_free(png_ptr, info_ptr->eXIf_buf);
2124 info_ptr->eXIf_buf = NULL;
2125 }
2126 #endif
2127
2128 #ifdef PNG_READ_hIST_SUPPORTED
2129 void /* PRIVATE */
2130 png_handle_hIST(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2131 {
2132 unsigned int num, i;
2133 png_uint_16 readbuf[PNG_MAX_PALETTE_LENGTH];
2134
2135 png_debug(1, "in png_handle_hIST");
2136
2137 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2138 png_chunk_error(png_ptr, "missing IHDR");
2139
2140 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0 ||
2141 (png_ptr->mode & PNG_HAVE_PLTE) == 0)
2142 {
2143 png_crc_finish(png_ptr, length);
2144 png_chunk_benign_error(png_ptr, "out of place");
2145 return;
2146 }
2147
2148 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST) != 0)
2149 {
2150 png_crc_finish(png_ptr, length);
2151 png_chunk_benign_error(png_ptr, "duplicate");
2152 return;
2153 }
2154
2155 num = length / 2 ;
2156
2157 if (num != (unsigned int) png_ptr->num_palette ||
2158 num > (unsigned int) PNG_MAX_PALETTE_LENGTH)
2159 {
2160 png_crc_finish(png_ptr, length);
2161 png_chunk_benign_error(png_ptr, "invalid");
2162 return;
2163 }
2164
2165 for (i = 0; i < num; i++)
2166 {
2167 png_byte buf[2];
2168
2169 png_crc_read(png_ptr, buf, 2);
2170 readbuf[i] = png_get_uint_16(buf);
2171 }
2172
2173 if (png_crc_finish(png_ptr, 0) != 0)
2174 return;
2175
2176 png_set_hIST(png_ptr, info_ptr, readbuf);
2177 }
2178 #endif
2179
2180 #ifdef PNG_READ_pHYs_SUPPORTED
2181 void /* PRIVATE */
2182 png_handle_pHYs(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2183 {
2184 png_byte buf[9];
2185 png_uint_32 res_x, res_y;
2186 int unit_type;
2187
2188 png_debug(1, "in png_handle_pHYs");
2189
2190 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2191 png_chunk_error(png_ptr, "missing IHDR");
2192
2193 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2194 {
2195 png_crc_finish(png_ptr, length);
2196 png_chunk_benign_error(png_ptr, "out of place");
2197 return;
2198 }
2199
2200 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs) != 0)
2201 {
2202 png_crc_finish(png_ptr, length);
2203 png_chunk_benign_error(png_ptr, "duplicate");
2204 return;
2205 }
2206
2207 if (length != 9)
2208 {
2209 png_crc_finish(png_ptr, length);
2210 png_chunk_benign_error(png_ptr, "invalid");
2211 return;
2212 }
2213
2214 png_crc_read(png_ptr, buf, 9);
2215
2216 if (png_crc_finish(png_ptr, 0) != 0)
2217 return;
2218
2219 res_x = png_get_uint_32(buf);
2220 res_y = png_get_uint_32(buf + 4);
2221 unit_type = buf[8];
2222 png_set_pHYs(png_ptr, info_ptr, res_x, res_y, unit_type);
2223 }
2224 #endif
2225
2226 #ifdef PNG_READ_oFFs_SUPPORTED
2227 void /* PRIVATE */
2228 png_handle_oFFs(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2229 {
2230 png_byte buf[9];
2231 png_int_32 offset_x, offset_y;
2232 int unit_type;
2233
2234 png_debug(1, "in png_handle_oFFs");
2235
2236 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2237 png_chunk_error(png_ptr, "missing IHDR");
2238
2239 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2240 {
2241 png_crc_finish(png_ptr, length);
2242 png_chunk_benign_error(png_ptr, "out of place");
2243 return;
2244 }
2245
2246 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs) != 0)
2247 {
2248 png_crc_finish(png_ptr, length);
2249 png_chunk_benign_error(png_ptr, "duplicate");
2250 return;
2251 }
2252
2253 if (length != 9)
2254 {
2255 png_crc_finish(png_ptr, length);
2256 png_chunk_benign_error(png_ptr, "invalid");
2257 return;
2258 }
2259
2260 png_crc_read(png_ptr, buf, 9);
2261
2262 if (png_crc_finish(png_ptr, 0) != 0)
2263 return;
2264
2265 offset_x = png_get_int_32(buf);
2266 offset_y = png_get_int_32(buf + 4);
2267 unit_type = buf[8];
2268 png_set_oFFs(png_ptr, info_ptr, offset_x, offset_y, unit_type);
2269 }
2270 #endif
2271
2272 #ifdef PNG_READ_pCAL_SUPPORTED
2273 /* Read the pCAL chunk (described in the PNG Extensions document) */
2274 void /* PRIVATE */
2275 png_handle_pCAL(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2276 {
2277 png_int_32 X0, X1;
2278 png_byte type, nparams;
2279 png_bytep buffer, buf, units, endptr;
2280 png_charpp params;
2281 int i;
2282
2283 png_debug(1, "in png_handle_pCAL");
2284
2285 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2286 png_chunk_error(png_ptr, "missing IHDR");
2287
2288 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2289 {
2290 png_crc_finish(png_ptr, length);
2291 png_chunk_benign_error(png_ptr, "out of place");
2292 return;
2293 }
2294
2295 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pCAL) != 0)
2296 {
2297 png_crc_finish(png_ptr, length);
2298 png_chunk_benign_error(png_ptr, "duplicate");
2299 return;
2300 }
2301
2302 png_debug1(2, "Allocating and reading pCAL chunk data (%u bytes)",
2303 length + 1);
2304
2305 buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/);
2306
2307 if (buffer == NULL)
2308 {
2309 png_crc_finish(png_ptr, length);
2310 png_chunk_benign_error(png_ptr, "out of memory");
2311 return;
2312 }
2313
2314 png_crc_read(png_ptr, buffer, length);
2315
2316 if (png_crc_finish(png_ptr, 0) != 0)
2317 return;
2318
2319 buffer[length] = 0; /* Null terminate the last string */
2320
2321 png_debug(3, "Finding end of pCAL purpose string");
2322 for (buf = buffer; *buf; buf++)
2323 /* Empty loop */ ;
2324
2325 endptr = buffer + length;
2326
2327 /* We need to have at least 12 bytes after the purpose string
2328 * in order to get the parameter information.
2329 */
2330 if (endptr - buf <= 12)
2331 {
2332 png_chunk_benign_error(png_ptr, "invalid");
2333 return;
2334 }
2335
2336 png_debug(3, "Reading pCAL X0, X1, type, nparams, and units");
2337 X0 = png_get_int_32((png_bytep)buf+1);
2338 X1 = png_get_int_32((png_bytep)buf+5);
2339 type = buf[9];
2340 nparams = buf[10];
2341 units = buf + 11;
2342
2343 png_debug(3, "Checking pCAL equation type and number of parameters");
2344 /* Check that we have the right number of parameters for known
2345 * equation types.
2346 */
2347 if ((type == PNG_EQUATION_LINEAR && nparams != 2) ||
2348 (type == PNG_EQUATION_BASE_E && nparams != 3) ||
2349 (type == PNG_EQUATION_ARBITRARY && nparams != 3) ||
2350 (type == PNG_EQUATION_HYPERBOLIC && nparams != 4))
2351 {
2352 png_chunk_benign_error(png_ptr, "invalid parameter count");
2353 return;
2354 }
2355
2356 else if (type >= PNG_EQUATION_LAST)
2357 {
2358 png_chunk_benign_error(png_ptr, "unrecognized equation type");
2359 }
2360
2361 for (buf = units; *buf; buf++)
2362 /* Empty loop to move past the units string. */ ;
2363
2364 png_debug(3, "Allocating pCAL parameters array");
2365
2366 params = png_voidcast(png_charpp, png_malloc_warn(png_ptr,
2367 nparams * (sizeof (png_charp))));
2368
2369 if (params == NULL)
2370 {
2371 png_chunk_benign_error(png_ptr, "out of memory");
2372 return;
2373 }
2374
2375 /* Get pointers to the start of each parameter string. */
2376 for (i = 0; i < nparams; i++)
2377 {
2378 buf++; /* Skip the null string terminator from previous parameter. */
2379
2380 png_debug1(3, "Reading pCAL parameter %d", i);
2381
2382 for (params[i] = (png_charp)buf; buf <= endptr && *buf != 0; buf++)
2383 /* Empty loop to move past each parameter string */ ;
2384
2385 /* Make sure we haven't run out of data yet */
2386 if (buf > endptr)
2387 {
2388 png_free(png_ptr, params);
2389 png_chunk_benign_error(png_ptr, "invalid data");
2390 return;
2391 }
2392 }
2393
2394 png_set_pCAL(png_ptr, info_ptr, (png_charp)buffer, X0, X1, type, nparams,
2395 (png_charp)units, params);
2396
2397 png_free(png_ptr, params);
2398 }
2399 #endif
2400
2401 #ifdef PNG_READ_sCAL_SUPPORTED
2402 /* Read the sCAL chunk */
2403 void /* PRIVATE */
2404 png_handle_sCAL(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2405 {
2406 png_bytep buffer;
2407 size_t i;
2408 int state;
2409
2410 png_debug(1, "in png_handle_sCAL");
2411
2412 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2413 png_chunk_error(png_ptr, "missing IHDR");
2414
2415 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2416 {
2417 png_crc_finish(png_ptr, length);
2418 png_chunk_benign_error(png_ptr, "out of place");
2419 return;
2420 }
2421
2422 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sCAL) != 0)
2423 {
2424 png_crc_finish(png_ptr, length);
2425 png_chunk_benign_error(png_ptr, "duplicate");
2426 return;
2427 }
2428
2429 /* Need unit type, width, \0, height: minimum 4 bytes */
2430 else if (length < 4)
2431 {
2432 png_crc_finish(png_ptr, length);
2433 png_chunk_benign_error(png_ptr, "invalid");
2434 return;
2435 }
2436
2437 png_debug1(2, "Allocating and reading sCAL chunk data (%u bytes)",
2438 length + 1);
2439
2440 buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/);
2441
2442 if (buffer == NULL)
2443 {
2444 png_chunk_benign_error(png_ptr, "out of memory");
2445 png_crc_finish(png_ptr, length);
2446 return;
2447 }
2448
2449 png_crc_read(png_ptr, buffer, length);
2450 buffer[length] = 0; /* Null terminate the last string */
2451
2452 if (png_crc_finish(png_ptr, 0) != 0)
2453 return;
2454
2455 /* Validate the unit. */
2456 if (buffer[0] != 1 && buffer[0] != 2)
2457 {
2458 png_chunk_benign_error(png_ptr, "invalid unit");
2459 return;
2460 }
2461
2462 /* Validate the ASCII numbers, need two ASCII numbers separated by
2463 * a '\0' and they need to fit exactly in the chunk data.
2464 */
2465 i = 1;
2466 state = 0;
2467
2468 if (png_check_fp_number((png_const_charp)buffer, length, &state, &i) == 0 ||
2469 i >= length || buffer[i++] != 0)
2470 png_chunk_benign_error(png_ptr, "bad width format");
2471
2472 else if (PNG_FP_IS_POSITIVE(state) == 0)
2473 png_chunk_benign_error(png_ptr, "non-positive width");
2474
2475 else
2476 {
2477 size_t heighti = i;
2478
2479 state = 0;
2480 if (png_check_fp_number((png_const_charp)buffer, length,
2481 &state, &i) == 0 || i != length)
2482 png_chunk_benign_error(png_ptr, "bad height format");
2483
2484 else if (PNG_FP_IS_POSITIVE(state) == 0)
2485 png_chunk_benign_error(png_ptr, "non-positive height");
2486
2487 else
2488 /* This is the (only) success case. */
2489 png_set_sCAL_s(png_ptr, info_ptr, buffer[0],
2490 (png_charp)buffer+1, (png_charp)buffer+heighti);
2491 }
2492 }
2493 #endif
2494
2495 #ifdef PNG_READ_tIME_SUPPORTED
2496 void /* PRIVATE */
2497 png_handle_tIME(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2498 {
2499 png_byte buf[7];
2500 png_time mod_time;
2501
2502 png_debug(1, "in png_handle_tIME");
2503
2504 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2505 png_chunk_error(png_ptr, "missing IHDR");
2506
2507 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tIME) != 0)
2508 {
2509 png_crc_finish(png_ptr, length);
2510 png_chunk_benign_error(png_ptr, "duplicate");
2511 return;
2512 }
2513
2514 if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2515 png_ptr->mode |= PNG_AFTER_IDAT;
2516
2517 if (length != 7)
2518 {
2519 png_crc_finish(png_ptr, length);
2520 png_chunk_benign_error(png_ptr, "invalid");
2521 return;
2522 }
2523
2524 png_crc_read(png_ptr, buf, 7);
2525
2526 if (png_crc_finish(png_ptr, 0) != 0)
2527 return;
2528
2529 mod_time.second = buf[6];
2530 mod_time.minute = buf[5];
2531 mod_time.hour = buf[4];
2532 mod_time.day = buf[3];
2533 mod_time.month = buf[2];
2534 mod_time.year = png_get_uint_16(buf);
2535
2536 png_set_tIME(png_ptr, info_ptr, &mod_time);
2537 }
2538 #endif
2539
2540 #ifdef PNG_READ_tEXt_SUPPORTED
2541 /* Note: this does not properly handle chunks that are > 64K under DOS */
2542 void /* PRIVATE */
2543 png_handle_tEXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2544 {
2545 png_text text_info;
2546 png_bytep buffer;
2547 png_charp key;
2548 png_charp text;
2549 png_uint_32 skip = 0;
2550
2551 png_debug(1, "in png_handle_tEXt");
2552
2553 #ifdef PNG_USER_LIMITS_SUPPORTED
2554 if (png_ptr->user_chunk_cache_max != 0)
2555 {
2556 if (png_ptr->user_chunk_cache_max == 1)
2557 {
2558 png_crc_finish(png_ptr, length);
2559 return;
2560 }
2561
2562 if (--png_ptr->user_chunk_cache_max == 1)
2563 {
2564 png_crc_finish(png_ptr, length);
2565 png_chunk_benign_error(png_ptr, "no space in chunk cache");
2566 return;
2567 }
2568 }
2569 #endif
2570
2571 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2572 png_chunk_error(png_ptr, "missing IHDR");
2573
2574 if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2575 png_ptr->mode |= PNG_AFTER_IDAT;
2576
2577 #ifdef PNG_MAX_MALLOC_64K
2578 if (length > 65535U)
2579 {
2580 png_crc_finish(png_ptr, length);
2581 png_chunk_benign_error(png_ptr, "too large to fit in memory");
2582 return;
2583 }
2584 #endif
2585
2586 buffer = png_read_buffer(png_ptr, length+1, 1/*warn*/);
2587
2588 if (buffer == NULL)
2589 {
2590 png_chunk_benign_error(png_ptr, "out of memory");
2591 return;
2592 }
2593
2594 png_crc_read(png_ptr, buffer, length);
2595
2596 if (png_crc_finish(png_ptr, skip) != 0)
2597 return;
2598
2599 key = (png_charp)buffer;
2600 key[length] = 0;
2601
2602 for (text = key; *text; text++)
2603 /* Empty loop to find end of key */ ;
2604
2605 if (text != key + length)
2606 text++;
2607
2608 text_info.compression = PNG_TEXT_COMPRESSION_NONE;
2609 text_info.key = key;
2610 text_info.lang = NULL;
2611 text_info.lang_key = NULL;
2612 text_info.itxt_length = 0;
2613 text_info.text = text;
2614 text_info.text_length = strlen(text);
2615
2616 if (png_set_text_2(png_ptr, info_ptr, &text_info, 1) != 0)
2617 png_warning(png_ptr, "Insufficient memory to process text chunk");
2618 }
2619 #endif
2620
2621 #ifdef PNG_READ_zTXt_SUPPORTED
2622 /* Note: this does not correctly handle chunks that are > 64K under DOS */
2623 void /* PRIVATE */
2624 png_handle_zTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2625 {
2626 png_const_charp errmsg = NULL;
2627 png_bytep buffer;
2628 png_uint_32 keyword_length;
2629
2630 png_debug(1, "in png_handle_zTXt");
2631
2632 #ifdef PNG_USER_LIMITS_SUPPORTED
2633 if (png_ptr->user_chunk_cache_max != 0)
2634 {
2635 if (png_ptr->user_chunk_cache_max == 1)
2636 {
2637 png_crc_finish(png_ptr, length);
2638 return;
2639 }
2640
2641 if (--png_ptr->user_chunk_cache_max == 1)
2642 {
2643 png_crc_finish(png_ptr, length);
2644 png_chunk_benign_error(png_ptr, "no space in chunk cache");
2645 return;
2646 }
2647 }
2648 #endif
2649
2650 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2651 png_chunk_error(png_ptr, "missing IHDR");
2652
2653 if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2654 png_ptr->mode |= PNG_AFTER_IDAT;
2655
2656 /* Note, "length" is sufficient here; we won't be adding
2657 * a null terminator later.
2658 */
2659 buffer = png_read_buffer(png_ptr, length, 2/*silent*/);
2660
2661 if (buffer == NULL)
2662 {
2663 png_crc_finish(png_ptr, length);
2664 png_chunk_benign_error(png_ptr, "out of memory");
2665 return;
2666 }
2667
2668 png_crc_read(png_ptr, buffer, length);
2669
2670 if (png_crc_finish(png_ptr, 0) != 0)
2671 return;
2672
2673 /* TODO: also check that the keyword contents match the spec! */
2674 for (keyword_length = 0;
2675 keyword_length < length && buffer[keyword_length] != 0;
2676 ++keyword_length)
2677 /* Empty loop to find end of name */ ;
2678
2679 if (keyword_length > 79 || keyword_length < 1)
2680 errmsg = "bad keyword";
2681
2682 /* zTXt must have some LZ data after the keyword, although it may expand to
2683 * zero bytes; we need a '\0' at the end of the keyword, the compression type
2684 * then the LZ data:
2685 */
2686 else if (keyword_length + 3 > length)
2687 errmsg = "truncated";
2688
2689 else if (buffer[keyword_length+1] != PNG_COMPRESSION_TYPE_BASE)
2690 errmsg = "unknown compression type";
2691
2692 else
2693 {
2694 png_alloc_size_t uncompressed_length = PNG_SIZE_MAX;
2695
2696 /* TODO: at present png_decompress_chunk imposes a single application
2697 * level memory limit, this should be split to different values for iCCP
2698 * and text chunks.
2699 */
2700 if (png_decompress_chunk(png_ptr, length, keyword_length+2,
2701 &uncompressed_length, 1/*terminate*/) == Z_STREAM_END)
2702 {
2703 png_text text;
2704
2705 if (png_ptr->read_buffer == NULL)
2706 errmsg="Read failure in png_handle_zTXt";
2707 else
2708 {
2709 /* It worked; png_ptr->read_buffer now looks like a tEXt chunk
2710 * except for the extra compression type byte and the fact that
2711 * it isn't necessarily '\0' terminated.
2712 */
2713 buffer = png_ptr->read_buffer;
2714 buffer[uncompressed_length+(keyword_length+2)] = 0;
2715
2716 text.compression = PNG_TEXT_COMPRESSION_zTXt;
2717 text.key = (png_charp)buffer;
2718 text.text = (png_charp)(buffer + keyword_length+2);
2719 text.text_length = uncompressed_length;
2720 text.itxt_length = 0;
2721 text.lang = NULL;
2722 text.lang_key = NULL;
2723
2724 if (png_set_text_2(png_ptr, info_ptr, &text, 1) != 0)
2725 errmsg = "insufficient memory";
2726 }
2727 }
2728
2729 else
2730 errmsg = png_ptr->zstream.msg;
2731 }
2732
2733 if (errmsg != NULL)
2734 png_chunk_benign_error(png_ptr, errmsg);
2735 }
2736 #endif
2737
2738 #ifdef PNG_READ_iTXt_SUPPORTED
2739 /* Note: this does not correctly handle chunks that are > 64K under DOS */
2740 void /* PRIVATE */
2741 png_handle_iTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2742 {
2743 png_const_charp errmsg = NULL;
2744 png_bytep buffer;
2745 png_uint_32 prefix_length;
2746
2747 png_debug(1, "in png_handle_iTXt");
2748
2749 #ifdef PNG_USER_LIMITS_SUPPORTED
2750 if (png_ptr->user_chunk_cache_max != 0)
2751 {
2752 if (png_ptr->user_chunk_cache_max == 1)
2753 {
2754 png_crc_finish(png_ptr, length);
2755 return;
2756 }
2757
2758 if (--png_ptr->user_chunk_cache_max == 1)
2759 {
2760 png_crc_finish(png_ptr, length);
2761 png_chunk_benign_error(png_ptr, "no space in chunk cache");
2762 return;
2763 }
2764 }
2765 #endif
2766
2767 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2768 png_chunk_error(png_ptr, "missing IHDR");
2769
2770 if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2771 png_ptr->mode |= PNG_AFTER_IDAT;
2772
2773 buffer = png_read_buffer(png_ptr, length+1, 1/*warn*/);
2774
2775 if (buffer == NULL)
2776 {
2777 png_crc_finish(png_ptr, length);
2778 png_chunk_benign_error(png_ptr, "out of memory");
2779 return;
2780 }
2781
2782 png_crc_read(png_ptr, buffer, length);
2783
2784 if (png_crc_finish(png_ptr, 0) != 0)
2785 return;
2786
2787 /* First the keyword. */
2788 for (prefix_length=0;
2789 prefix_length < length && buffer[prefix_length] != 0;
2790 ++prefix_length)
2791 /* Empty loop */ ;
2792
2793 /* Perform a basic check on the keyword length here. */
2794 if (prefix_length > 79 || prefix_length < 1)
2795 errmsg = "bad keyword";
2796
2797 /* Expect keyword, compression flag, compression type, language, translated
2798 * keyword (both may be empty but are 0 terminated) then the text, which may
2799 * be empty.
2800 */
2801 else if (prefix_length + 5 > length)
2802 errmsg = "truncated";
2803
2804 else if (buffer[prefix_length+1] == 0 ||
2805 (buffer[prefix_length+1] == 1 &&
2806 buffer[prefix_length+2] == PNG_COMPRESSION_TYPE_BASE))
2807 {
2808 int compressed = buffer[prefix_length+1] != 0;
2809 png_uint_32 language_offset, translated_keyword_offset;
2810 png_alloc_size_t uncompressed_length = 0;
2811
2812 /* Now the language tag */
2813 prefix_length += 3;
2814 language_offset = prefix_length;
2815
2816 for (; prefix_length < length && buffer[prefix_length] != 0;
2817 ++prefix_length)
2818 /* Empty loop */ ;
2819
2820 /* WARNING: the length may be invalid here, this is checked below. */
2821 translated_keyword_offset = ++prefix_length;
2822
2823 for (; prefix_length < length && buffer[prefix_length] != 0;
2824 ++prefix_length)
2825 /* Empty loop */ ;
2826
2827 /* prefix_length should now be at the trailing '\0' of the translated
2828 * keyword, but it may already be over the end. None of this arithmetic
2829 * can overflow because chunks are at most 2^31 bytes long, but on 16-bit
2830 * systems the available allocation may overflow.
2831 */
2832 ++prefix_length;
2833
2834 if (compressed == 0 && prefix_length <= length)
2835 uncompressed_length = length - prefix_length;
2836
2837 else if (compressed != 0 && prefix_length < length)
2838 {
2839 uncompressed_length = PNG_SIZE_MAX;
2840
2841 /* TODO: at present png_decompress_chunk imposes a single application
2842 * level memory limit, this should be split to different values for
2843 * iCCP and text chunks.
2844 */
2845 if (png_decompress_chunk(png_ptr, length, prefix_length,
2846 &uncompressed_length, 1/*terminate*/) == Z_STREAM_END)
2847 buffer = png_ptr->read_buffer;
2848
2849 else
2850 errmsg = png_ptr->zstream.msg;
2851 }
2852
2853 else
2854 errmsg = "truncated";
2855
2856 if (errmsg == NULL)
2857 {
2858 png_text text;
2859
2860 buffer[uncompressed_length+prefix_length] = 0;
2861
2862 if (compressed == 0)
2863 text.compression = PNG_ITXT_COMPRESSION_NONE;
2864
2865 else
2866 text.compression = PNG_ITXT_COMPRESSION_zTXt;
2867
2868 text.key = (png_charp)buffer;
2869 text.lang = (png_charp)buffer + language_offset;
2870 text.lang_key = (png_charp)buffer + translated_keyword_offset;
2871 text.text = (png_charp)buffer + prefix_length;
2872 text.text_length = 0;
2873 text.itxt_length = uncompressed_length;
2874
2875 if (png_set_text_2(png_ptr, info_ptr, &text, 1) != 0)
2876 errmsg = "insufficient memory";
2877 }
2878 }
2879
2880 else
2881 errmsg = "bad compression info";
2882
2883 if (errmsg != NULL)
2884 png_chunk_benign_error(png_ptr, errmsg);
2885 }
2886 #endif
2887
2888 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
2889 /* Utility function for png_handle_unknown; set up png_ptr::unknown_chunk */
2890 static int
2891 png_cache_unknown_chunk(png_structrp png_ptr, png_uint_32 length)
2892 {
2893 png_alloc_size_t limit = PNG_SIZE_MAX;
2894
2895 if (png_ptr->unknown_chunk.data != NULL)
2896 {
2897 png_free(png_ptr, png_ptr->unknown_chunk.data);
2898 png_ptr->unknown_chunk.data = NULL;
2899 }
2900
2901 # ifdef PNG_SET_USER_LIMITS_SUPPORTED
2902 if (png_ptr->user_chunk_malloc_max > 0 &&
2903 png_ptr->user_chunk_malloc_max < limit)
2904 limit = png_ptr->user_chunk_malloc_max;
2905
2906 # elif PNG_USER_CHUNK_MALLOC_MAX > 0
2907 if (PNG_USER_CHUNK_MALLOC_MAX < limit)
2908 limit = PNG_USER_CHUNK_MALLOC_MAX;
2909 # endif
2910
2911 if (length <= limit)
2912 {
2913 PNG_CSTRING_FROM_CHUNK(png_ptr->unknown_chunk.name, png_ptr->chunk_name);
2914 /* The following is safe because of the PNG_SIZE_MAX init above */
2915 png_ptr->unknown_chunk.size = (size_t)length/*SAFE*/;
2916 /* 'mode' is a flag array, only the bottom four bits matter here */
2917 png_ptr->unknown_chunk.location = (png_byte)png_ptr->mode/*SAFE*/;
2918
2919 if (length == 0)
2920 png_ptr->unknown_chunk.data = NULL;
2921
2922 else
2923 {
2924 /* Do a 'warn' here - it is handled below. */
2925 png_ptr->unknown_chunk.data = png_voidcast(png_bytep,
2926 png_malloc_warn(png_ptr, length));
2927 }
2928 }
2929
2930 if (png_ptr->unknown_chunk.data == NULL && length > 0)
2931 {
2932 /* This is benign because we clean up correctly */
2933 png_crc_finish(png_ptr, length);
2934 png_chunk_benign_error(png_ptr, "unknown chunk exceeds memory limits");
2935 return 0;
2936 }
2937
2938 else
2939 {
2940 if (length > 0)
2941 png_crc_read(png_ptr, png_ptr->unknown_chunk.data, length);
2942 png_crc_finish(png_ptr, 0);
2943 return 1;
2944 }
2945 }
2946 #endif /* READ_UNKNOWN_CHUNKS */
2947
2948 /* Handle an unknown, or known but disabled, chunk */
2949 void /* PRIVATE */
2950 png_handle_unknown(png_structrp png_ptr, png_inforp info_ptr,
2951 png_uint_32 length, int keep)
2952 {
2953 int handled = 0; /* the chunk was handled */
2954
2955 png_debug(1, "in png_handle_unknown");
2956
2957 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
2958 /* NOTE: this code is based on the code in libpng-1.4.12 except for fixing
2959 * the bug which meant that setting a non-default behavior for a specific
2960 * chunk would be ignored (the default was always used unless a user
2961 * callback was installed).
2962 *
2963 * 'keep' is the value from the png_chunk_unknown_handling, the setting for
2964 * this specific chunk_name, if PNG_HANDLE_AS_UNKNOWN_SUPPORTED, if not it
2965 * will always be PNG_HANDLE_CHUNK_AS_DEFAULT and it needs to be set here.
2966 * This is just an optimization to avoid multiple calls to the lookup
2967 * function.
2968 */
2969 # ifndef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
2970 # ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
2971 keep = png_chunk_unknown_handling(png_ptr, png_ptr->chunk_name);
2972 # endif
2973 # endif
2974
2975 /* One of the following methods will read the chunk or skip it (at least one
2976 * of these is always defined because this is the only way to switch on
2977 * PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
2978 */
2979 # ifdef PNG_READ_USER_CHUNKS_SUPPORTED
2980 /* The user callback takes precedence over the chunk keep value, but the
2981 * keep value is still required to validate a save of a critical chunk.
2982 */
2983 if (png_ptr->read_user_chunk_fn != NULL)
2984 {
2985 if (png_cache_unknown_chunk(png_ptr, length) != 0)
2986 {
2987 /* Callback to user unknown chunk handler */
2988 int ret = (*(png_ptr->read_user_chunk_fn))(png_ptr,
2989 &png_ptr->unknown_chunk);
2990
2991 /* ret is:
2992 * negative: An error occurred; png_chunk_error will be called.
2993 * zero: The chunk was not handled, the chunk will be discarded
2994 * unless png_set_keep_unknown_chunks has been used to set
2995 * a 'keep' behavior for this particular chunk, in which
2996 * case that will be used. A critical chunk will cause an
2997 * error at this point unless it is to be saved.
2998 * positive: The chunk was handled, libpng will ignore/discard it.
2999 */
3000 if (ret < 0)
3001 png_chunk_error(png_ptr, "error in user chunk");
3002
3003 else if (ret == 0)
3004 {
3005 /* If the keep value is 'default' or 'never' override it, but
3006 * still error out on critical chunks unless the keep value is
3007 * 'always' While this is weird it is the behavior in 1.4.12.
3008 * A possible improvement would be to obey the value set for the
3009 * chunk, but this would be an API change that would probably
3010 * damage some applications.
3011 *
3012 * The png_app_warning below catches the case that matters, where
3013 * the application has not set specific save or ignore for this
3014 * chunk or global save or ignore.
3015 */
3016 if (keep < PNG_HANDLE_CHUNK_IF_SAFE)
3017 {
3018 # ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
3019 if (png_ptr->unknown_default < PNG_HANDLE_CHUNK_IF_SAFE)
3020 {
3021 png_chunk_warning(png_ptr, "Saving unknown chunk:");
3022 png_app_warning(png_ptr,
3023 "forcing save of an unhandled chunk;"
3024 " please call png_set_keep_unknown_chunks");
3025 /* with keep = PNG_HANDLE_CHUNK_IF_SAFE */
3026 }
3027 # endif
3028 keep = PNG_HANDLE_CHUNK_IF_SAFE;
3029 }
3030 }
3031
3032 else /* chunk was handled */
3033 {
3034 handled = 1;
3035 /* Critical chunks can be safely discarded at this point. */
3036 keep = PNG_HANDLE_CHUNK_NEVER;
3037 }
3038 }
3039
3040 else
3041 keep = PNG_HANDLE_CHUNK_NEVER; /* insufficient memory */
3042 }
3043
3044 else
3045 /* Use the SAVE_UNKNOWN_CHUNKS code or skip the chunk */
3046 # endif /* READ_USER_CHUNKS */
3047
3048 # ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED
3049 {
3050 /* keep is currently just the per-chunk setting, if there was no
3051 * setting change it to the global default now (not that this may
3052 * still be AS_DEFAULT) then obtain the cache of the chunk if required,
3053 * if not simply skip the chunk.
3054 */
3055 if (keep == PNG_HANDLE_CHUNK_AS_DEFAULT)
3056 keep = png_ptr->unknown_default;
3057
3058 if (keep == PNG_HANDLE_CHUNK_ALWAYS ||
3059 (keep == PNG_HANDLE_CHUNK_IF_SAFE &&
3060 PNG_CHUNK_ANCILLARY(png_ptr->chunk_name)))
3061 {
3062 if (png_cache_unknown_chunk(png_ptr, length) == 0)
3063 keep = PNG_HANDLE_CHUNK_NEVER;
3064 }
3065
3066 else
3067 png_crc_finish(png_ptr, length);
3068 }
3069 # else
3070 # ifndef PNG_READ_USER_CHUNKS_SUPPORTED
3071 # error no method to support READ_UNKNOWN_CHUNKS
3072 # endif
3073
3074 {
3075 /* If here there is no read callback pointer set and no support is
3076 * compiled in to just save the unknown chunks, so simply skip this
3077 * chunk. If 'keep' is something other than AS_DEFAULT or NEVER then
3078 * the app has erroneously asked for unknown chunk saving when there
3079 * is no support.
3080 */
3081 if (keep > PNG_HANDLE_CHUNK_NEVER)
3082 png_app_error(png_ptr, "no unknown chunk support available");
3083
3084 png_crc_finish(png_ptr, length);
3085 }
3086 # endif
3087
3088 # ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
3089 /* Now store the chunk in the chunk list if appropriate, and if the limits
3090 * permit it.
3091 */
3092 if (keep == PNG_HANDLE_CHUNK_ALWAYS ||
3093 (keep == PNG_HANDLE_CHUNK_IF_SAFE &&
3094 PNG_CHUNK_ANCILLARY(png_ptr->chunk_name)))
3095 {
3096 # ifdef PNG_USER_LIMITS_SUPPORTED
3097 switch (png_ptr->user_chunk_cache_max)
3098 {
3099 case 2:
3100 png_ptr->user_chunk_cache_max = 1;
3101 png_chunk_benign_error(png_ptr, "no space in chunk cache");
3102 /* FALLTHROUGH */
3103 case 1:
3104 /* NOTE: prior to 1.6.0 this case resulted in an unknown critical
3105 * chunk being skipped, now there will be a hard error below.
3106 */
3107 break;
3108
3109 default: /* not at limit */
3110 --(png_ptr->user_chunk_cache_max);
3111 /* FALLTHROUGH */
3112 case 0: /* no limit */
3113 # endif /* USER_LIMITS */
3114 /* Here when the limit isn't reached or when limits are compiled
3115 * out; store the chunk.
3116 */
3117 png_set_unknown_chunks(png_ptr, info_ptr,
3118 &png_ptr->unknown_chunk, 1);
3119 handled = 1;
3120 # ifdef PNG_USER_LIMITS_SUPPORTED
3121 break;
3122 }
3123 # endif
3124 }
3125 # else /* no store support: the chunk must be handled by the user callback */
3126 PNG_UNUSED(info_ptr)
3127 # endif
3128
3129 /* Regardless of the error handling below the cached data (if any) can be
3130 * freed now. Notice that the data is not freed if there is a png_error, but
3131 * it will be freed by destroy_read_struct.
3132 */
3133 if (png_ptr->unknown_chunk.data != NULL)
3134 png_free(png_ptr, png_ptr->unknown_chunk.data);
3135 png_ptr->unknown_chunk.data = NULL;
3136
3137 #else /* !PNG_READ_UNKNOWN_CHUNKS_SUPPORTED */
3138 /* There is no support to read an unknown chunk, so just skip it. */
3139 png_crc_finish(png_ptr, length);
3140 PNG_UNUSED(info_ptr)
3141 PNG_UNUSED(keep)
3142 #endif /* !READ_UNKNOWN_CHUNKS */
3143
3144 /* Check for unhandled critical chunks */
3145 if (handled == 0 && PNG_CHUNK_CRITICAL(png_ptr->chunk_name))
3146 png_chunk_error(png_ptr, "unhandled critical chunk");
3147 }
3148
3149 /* This function is called to verify that a chunk name is valid.
3150 * This function can't have the "critical chunk check" incorporated
3151 * into it, since in the future we will need to be able to call user
3152 * functions to handle unknown critical chunks after we check that
3153 * the chunk name itself is valid.
3154 */
3155
3156 /* Bit hacking: the test for an invalid byte in the 4 byte chunk name is:
3157 *
3158 * ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97))
3159 */
3160
3161 void /* PRIVATE */
3162 png_check_chunk_name(png_const_structrp png_ptr, png_uint_32 chunk_name)
3163 {
3164 int i;
3165 png_uint_32 cn=chunk_name;
3166
3167 png_debug(1, "in png_check_chunk_name");
3168
3169 for (i=1; i<=4; ++i)
3170 {
3171 int c = cn & 0xff;
3172
3173 if (c < 65 || c > 122 || (c > 90 && c < 97))
3174 png_chunk_error(png_ptr, "invalid chunk type");
3175
3176 cn >>= 8;
3177 }
3178 }
3179
3180 void /* PRIVATE */
3181 png_check_chunk_length(png_const_structrp png_ptr, png_uint_32 length)
3182 {
3183 png_alloc_size_t limit = PNG_UINT_31_MAX;
3184
3185 # ifdef PNG_SET_USER_LIMITS_SUPPORTED
3186 if (png_ptr->user_chunk_malloc_max > 0 &&
3187 png_ptr->user_chunk_malloc_max < limit)
3188 limit = png_ptr->user_chunk_malloc_max;
3189 # elif PNG_USER_CHUNK_MALLOC_MAX > 0
3190 if (PNG_USER_CHUNK_MALLOC_MAX < limit)
3191 limit = PNG_USER_CHUNK_MALLOC_MAX;
3192 # endif
3193 if (png_ptr->chunk_name == png_IDAT)
3194 {
3195 png_alloc_size_t idat_limit = PNG_UINT_31_MAX;
3196 size_t row_factor =
3197 (size_t)png_ptr->width
3198 * (size_t)png_ptr->channels
3199 * (png_ptr->bit_depth > 8? 2: 1)
3200 + 1
3201 + (png_ptr->interlaced? 6: 0);
3202 if (png_ptr->height > PNG_UINT_32_MAX/row_factor)
3203 idat_limit = PNG_UINT_31_MAX;
3204 else
3205 idat_limit = png_ptr->height * row_factor;
3206 row_factor = row_factor > 32566? 32566 : row_factor;
3207 idat_limit += 6 + 5*(idat_limit/row_factor+1); /* zlib+deflate overhead */
3208 idat_limit=idat_limit < PNG_UINT_31_MAX? idat_limit : PNG_UINT_31_MAX;
3209 limit = limit < idat_limit? idat_limit : limit;
3210 }
3211
3212 if (length > limit)
3213 {
3214 png_debug2(0," length = %lu, limit = %lu",
3215 (unsigned long)length,(unsigned long)limit);
3216 png_chunk_error(png_ptr, "chunk data is too large");
3217 }
3218 }
3219
3220 /* Combines the row recently read in with the existing pixels in the row. This
3221 * routine takes care of alpha and transparency if requested. This routine also
3222 * handles the two methods of progressive display of interlaced images,
3223 * depending on the 'display' value; if 'display' is true then the whole row
3224 * (dp) is filled from the start by replicating the available pixels. If
3225 * 'display' is false only those pixels present in the pass are filled in.
3226 */
3227 void /* PRIVATE */
3228 png_combine_row(png_const_structrp png_ptr, png_bytep dp, int display)
3229 {
3230 unsigned int pixel_depth = png_ptr->transformed_pixel_depth;
3231 png_const_bytep sp = png_ptr->row_buf + 1;
3232 png_alloc_size_t row_width = png_ptr->width;
3233 unsigned int pass = png_ptr->pass;
3234 png_bytep end_ptr = 0;
3235 png_byte end_byte = 0;
3236 unsigned int end_mask;
3237
3238 png_debug(1, "in png_combine_row");
3239
3240 /* Added in 1.5.6: it should not be possible to enter this routine until at
3241 * least one row has been read from the PNG data and transformed.
3242 */
3243 if (pixel_depth == 0)
3244 png_error(png_ptr, "internal row logic error");
3245
3246 /* Added in 1.5.4: the pixel depth should match the information returned by
3247 * any call to png_read_update_info at this point. Do not continue if we got
3248 * this wrong.
3249 */
3250 if (png_ptr->info_rowbytes != 0 && png_ptr->info_rowbytes !=
3251 PNG_ROWBYTES(pixel_depth, row_width))
3252 png_error(png_ptr, "internal row size calculation error");
3253
3254 /* Don't expect this to ever happen: */
3255 if (row_width == 0)
3256 png_error(png_ptr, "internal row width error");
3257
3258 /* Preserve the last byte in cases where only part of it will be overwritten,
3259 * the multiply below may overflow, we don't care because ANSI-C guarantees
3260 * we get the low bits.
3261 */
3262 end_mask = (pixel_depth * row_width) & 7;
3263 if (end_mask != 0)
3264 {
3265 /* end_ptr == NULL is a flag to say do nothing */
3266 end_ptr = dp + PNG_ROWBYTES(pixel_depth, row_width) - 1;
3267 end_byte = *end_ptr;
3268 # ifdef PNG_READ_PACKSWAP_SUPPORTED
3269 if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
3270 /* little-endian byte */
3271 end_mask = (unsigned int)(0xff << end_mask);
3272
3273 else /* big-endian byte */
3274 # endif
3275 end_mask = 0xff >> end_mask;
3276 /* end_mask is now the bits to *keep* from the destination row */
3277 }
3278
3279 /* For non-interlaced images this reduces to a memcpy(). A memcpy()
3280 * will also happen if interlacing isn't supported or if the application
3281 * does not call png_set_interlace_handling(). In the latter cases the
3282 * caller just gets a sequence of the unexpanded rows from each interlace
3283 * pass.
3284 */
3285 #ifdef PNG_READ_INTERLACING_SUPPORTED
3286 if (png_ptr->interlaced != 0 &&
3287 (png_ptr->transformations & PNG_INTERLACE) != 0 &&
3288 pass < 6 && (display == 0 ||
3289 /* The following copies everything for 'display' on passes 0, 2 and 4. */
3290 (display == 1 && (pass & 1) != 0)))
3291 {
3292 /* Narrow images may have no bits in a pass; the caller should handle
3293 * this, but this test is cheap:
3294 */
3295 if (row_width <= PNG_PASS_START_COL(pass))
3296 return;
3297
3298 if (pixel_depth < 8)
3299 {
3300 /* For pixel depths up to 4 bpp the 8-pixel mask can be expanded to fit
3301 * into 32 bits, then a single loop over the bytes using the four byte
3302 * values in the 32-bit mask can be used. For the 'display' option the
3303 * expanded mask may also not require any masking within a byte. To
3304 * make this work the PACKSWAP option must be taken into account - it
3305 * simply requires the pixels to be reversed in each byte.
3306 *
3307 * The 'regular' case requires a mask for each of the first 6 passes,
3308 * the 'display' case does a copy for the even passes in the range
3309 * 0..6. This has already been handled in the test above.
3310 *
3311 * The masks are arranged as four bytes with the first byte to use in
3312 * the lowest bits (little-endian) regardless of the order (PACKSWAP or
3313 * not) of the pixels in each byte.
3314 *
3315 * NOTE: the whole of this logic depends on the caller of this function
3316 * only calling it on rows appropriate to the pass. This function only
3317 * understands the 'x' logic; the 'y' logic is handled by the caller.
3318 *
3319 * The following defines allow generation of compile time constant bit
3320 * masks for each pixel depth and each possibility of swapped or not
3321 * swapped bytes. Pass 'p' is in the range 0..6; 'x', a pixel index,
3322 * is in the range 0..7; and the result is 1 if the pixel is to be
3323 * copied in the pass, 0 if not. 'S' is for the sparkle method, 'B'
3324 * for the block method.
3325 *
3326 * With some compilers a compile time expression of the general form:
3327 *
3328 * (shift >= 32) ? (a >> (shift-32)) : (b >> shift)
3329 *
3330 * Produces warnings with values of 'shift' in the range 33 to 63
3331 * because the right hand side of the ?: expression is evaluated by
3332 * the compiler even though it isn't used. Microsoft Visual C (various
3333 * versions) and the Intel C compiler are known to do this. To avoid
3334 * this the following macros are used in 1.5.6. This is a temporary
3335 * solution to avoid destabilizing the code during the release process.
3336 */
3337 # if PNG_USE_COMPILE_TIME_MASKS
3338 # define PNG_LSR(x,s) ((x)>>((s) & 0x1f))
3339 # define PNG_LSL(x,s) ((x)<<((s) & 0x1f))
3340 # else
3341 # define PNG_LSR(x,s) ((x)>>(s))
3342 # define PNG_LSL(x,s) ((x)<<(s))
3343 # endif
3344 # define S_COPY(p,x) (((p)<4 ? PNG_LSR(0x80088822,(3-(p))*8+(7-(x))) :\
3345 PNG_LSR(0xaa55ff00,(7-(p))*8+(7-(x)))) & 1)
3346 # define B_COPY(p,x) (((p)<4 ? PNG_LSR(0xff0fff33,(3-(p))*8+(7-(x))) :\
3347 PNG_LSR(0xff55ff00,(7-(p))*8+(7-(x)))) & 1)
3348
3349 /* Return a mask for pass 'p' pixel 'x' at depth 'd'. The mask is
3350 * little endian - the first pixel is at bit 0 - however the extra
3351 * parameter 's' can be set to cause the mask position to be swapped
3352 * within each byte, to match the PNG format. This is done by XOR of
3353 * the shift with 7, 6 or 4 for bit depths 1, 2 and 4.
3354 */
3355 # define PIXEL_MASK(p,x,d,s) \
3356 (PNG_LSL(((PNG_LSL(1U,(d)))-1),(((x)*(d))^((s)?8-(d):0))))
3357
3358 /* Hence generate the appropriate 'block' or 'sparkle' pixel copy mask.
3359 */
3360 # define S_MASKx(p,x,d,s) (S_COPY(p,x)?PIXEL_MASK(p,x,d,s):0)
3361 # define B_MASKx(p,x,d,s) (B_COPY(p,x)?PIXEL_MASK(p,x,d,s):0)
3362
3363 /* Combine 8 of these to get the full mask. For the 1-bpp and 2-bpp
3364 * cases the result needs replicating, for the 4-bpp case the above
3365 * generates a full 32 bits.
3366 */
3367 # define MASK_EXPAND(m,d) ((m)*((d)==1?0x01010101:((d)==2?0x00010001:1)))
3368
3369 # define S_MASK(p,d,s) MASK_EXPAND(S_MASKx(p,0,d,s) + S_MASKx(p,1,d,s) +\
3370 S_MASKx(p,2,d,s) + S_MASKx(p,3,d,s) + S_MASKx(p,4,d,s) +\
3371 S_MASKx(p,5,d,s) + S_MASKx(p,6,d,s) + S_MASKx(p,7,d,s), d)
3372
3373 # define B_MASK(p,d,s) MASK_EXPAND(B_MASKx(p,0,d,s) + B_MASKx(p,1,d,s) +\
3374 B_MASKx(p,2,d,s) + B_MASKx(p,3,d,s) + B_MASKx(p,4,d,s) +\
3375 B_MASKx(p,5,d,s) + B_MASKx(p,6,d,s) + B_MASKx(p,7,d,s), d)
3376
3377 #if PNG_USE_COMPILE_TIME_MASKS
3378 /* Utility macros to construct all the masks for a depth/swap
3379 * combination. The 's' parameter says whether the format is PNG
3380 * (big endian bytes) or not. Only the three odd-numbered passes are
3381 * required for the display/block algorithm.
3382 */
3383 # define S_MASKS(d,s) { S_MASK(0,d,s), S_MASK(1,d,s), S_MASK(2,d,s),\
3384 S_MASK(3,d,s), S_MASK(4,d,s), S_MASK(5,d,s) }
3385
3386 # define B_MASKS(d,s) { B_MASK(1,d,s), B_MASK(3,d,s), B_MASK(5,d,s) }
3387
3388 # define DEPTH_INDEX(d) ((d)==1?0:((d)==2?1:2))
3389
3390 /* Hence the pre-compiled masks indexed by PACKSWAP (or not), depth and
3391 * then pass:
3392 */
3393 static const png_uint_32 row_mask[2/*PACKSWAP*/][3/*depth*/][6] =
3394 {
3395 /* Little-endian byte masks for PACKSWAP */
3396 { S_MASKS(1,0), S_MASKS(2,0), S_MASKS(4,0) },
3397 /* Normal (big-endian byte) masks - PNG format */
3398 { S_MASKS(1,1), S_MASKS(2,1), S_MASKS(4,1) }
3399 };
3400
3401 /* display_mask has only three entries for the odd passes, so index by
3402 * pass>>1.
3403 */
3404 static const png_uint_32 display_mask[2][3][3] =
3405 {
3406 /* Little-endian byte masks for PACKSWAP */
3407 { B_MASKS(1,0), B_MASKS(2,0), B_MASKS(4,0) },
3408 /* Normal (big-endian byte) masks - PNG format */
3409 { B_MASKS(1,1), B_MASKS(2,1), B_MASKS(4,1) }
3410 };
3411
3412 # define MASK(pass,depth,display,png)\
3413 ((display)?display_mask[png][DEPTH_INDEX(depth)][pass>>1]:\
3414 row_mask[png][DEPTH_INDEX(depth)][pass])
3415
3416 #else /* !PNG_USE_COMPILE_TIME_MASKS */
3417 /* This is the runtime alternative: it seems unlikely that this will
3418 * ever be either smaller or faster than the compile time approach.
3419 */
3420 # define MASK(pass,depth,display,png)\
3421 ((display)?B_MASK(pass,depth,png):S_MASK(pass,depth,png))
3422 #endif /* !USE_COMPILE_TIME_MASKS */
3423
3424 /* Use the appropriate mask to copy the required bits. In some cases
3425 * the byte mask will be 0 or 0xff; optimize these cases. row_width is
3426 * the number of pixels, but the code copies bytes, so it is necessary
3427 * to special case the end.
3428 */
3429 png_uint_32 pixels_per_byte = 8 / pixel_depth;
3430 png_uint_32 mask;
3431
3432 # ifdef PNG_READ_PACKSWAP_SUPPORTED
3433 if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
3434 mask = MASK(pass, pixel_depth, display, 0);
3435
3436 else
3437 # endif
3438 mask = MASK(pass, pixel_depth, display, 1);
3439
3440 for (;;)
3441 {
3442 png_uint_32 m;
3443
3444 /* It doesn't matter in the following if png_uint_32 has more than
3445 * 32 bits because the high bits always match those in m<<24; it is,
3446 * however, essential to use OR here, not +, because of this.
3447 */
3448 m = mask;
3449 mask = (m >> 8) | (m << 24); /* rotate right to good compilers */
3450 m &= 0xff;
3451
3452 if (m != 0) /* something to copy */
3453 {
3454 if (m != 0xff)
3455 *dp = (png_byte)((*dp & ~m) | (*sp & m));
3456 else
3457 *dp = *sp;
3458 }
3459
3460 /* NOTE: this may overwrite the last byte with garbage if the image
3461 * is not an exact number of bytes wide; libpng has always done
3462 * this.
3463 */
3464 if (row_width <= pixels_per_byte)
3465 break; /* May need to restore part of the last byte */
3466
3467 row_width -= pixels_per_byte;
3468 ++dp;
3469 ++sp;
3470 }
3471 }
3472
3473 else /* pixel_depth >= 8 */
3474 {
3475 unsigned int bytes_to_copy, bytes_to_jump;
3476
3477 /* Validate the depth - it must be a multiple of 8 */
3478 if (pixel_depth & 7)
3479 png_error(png_ptr, "invalid user transform pixel depth");
3480
3481 pixel_depth >>= 3; /* now in bytes */
3482 row_width *= pixel_depth;
3483
3484 /* Regardless of pass number the Adam 7 interlace always results in a
3485 * fixed number of pixels to copy then to skip. There may be a
3486 * different number of pixels to skip at the start though.
3487 */
3488 {
3489 unsigned int offset = PNG_PASS_START_COL(pass) * pixel_depth;
3490
3491 row_width -= offset;
3492 dp += offset;
3493 sp += offset;
3494 }
3495
3496 /* Work out the bytes to copy. */
3497 if (display != 0)
3498 {
3499 /* When doing the 'block' algorithm the pixel in the pass gets
3500 * replicated to adjacent pixels. This is why the even (0,2,4,6)
3501 * passes are skipped above - the entire expanded row is copied.
3502 */
3503 bytes_to_copy = (1<<((6-pass)>>1)) * pixel_depth;
3504
3505 /* But don't allow this number to exceed the actual row width. */
3506 if (bytes_to_copy > row_width)
3507 bytes_to_copy = (unsigned int)/*SAFE*/row_width;
3508 }
3509
3510 else /* normal row; Adam7 only ever gives us one pixel to copy. */
3511 bytes_to_copy = pixel_depth;
3512
3513 /* In Adam7 there is a constant offset between where the pixels go. */
3514 bytes_to_jump = PNG_PASS_COL_OFFSET(pass) * pixel_depth;
3515
3516 /* And simply copy these bytes. Some optimization is possible here,
3517 * depending on the value of 'bytes_to_copy'. Special case the low
3518 * byte counts, which we know to be frequent.
3519 *
3520 * Notice that these cases all 'return' rather than 'break' - this
3521 * avoids an unnecessary test on whether to restore the last byte
3522 * below.
3523 */
3524 switch (bytes_to_copy)
3525 {
3526 case 1:
3527 for (;;)
3528 {
3529 *dp = *sp;
3530
3531 if (row_width <= bytes_to_jump)
3532 return;
3533
3534 dp += bytes_to_jump;
3535 sp += bytes_to_jump;
3536 row_width -= bytes_to_jump;
3537 }
3538
3539 case 2:
3540 /* There is a possibility of a partial copy at the end here; this
3541 * slows the code down somewhat.
3542 */
3543 do
3544 {
3545 dp[0] = sp[0]; dp[1] = sp[1];
3546
3547 if (row_width <= bytes_to_jump)
3548 return;
3549
3550 sp += bytes_to_jump;
3551 dp += bytes_to_jump;
3552 row_width -= bytes_to_jump;
3553 }
3554 while (row_width > 1);
3555
3556 /* And there can only be one byte left at this point: */
3557 *dp = *sp;
3558 return;
3559
3560 case 3:
3561 /* This can only be the RGB case, so each copy is exactly one
3562 * pixel and it is not necessary to check for a partial copy.
3563 */
3564 for (;;)
3565 {
3566 dp[0] = sp[0]; dp[1] = sp[1]; dp[2] = sp[2];
3567
3568 if (row_width <= bytes_to_jump)
3569 return;
3570
3571 sp += bytes_to_jump;
3572 dp += bytes_to_jump;
3573 row_width -= bytes_to_jump;
3574 }
3575
3576 default:
3577 #if PNG_ALIGN_TYPE != PNG_ALIGN_NONE
3578 /* Check for double byte alignment and, if possible, use a
3579 * 16-bit copy. Don't attempt this for narrow images - ones that
3580 * are less than an interlace panel wide. Don't attempt it for
3581 * wide bytes_to_copy either - use the memcpy there.
3582 */
3583 if (bytes_to_copy < 16 /*else use memcpy*/ &&
3584 png_isaligned(dp, png_uint_16) &&
3585 png_isaligned(sp, png_uint_16) &&
3586 bytes_to_copy % (sizeof (png_uint_16)) == 0 &&
3587 bytes_to_jump % (sizeof (png_uint_16)) == 0)
3588 {
3589 /* Everything is aligned for png_uint_16 copies, but try for
3590 * png_uint_32 first.
3591 */
3592 if (png_isaligned(dp, png_uint_32) &&
3593 png_isaligned(sp, png_uint_32) &&
3594 bytes_to_copy % (sizeof (png_uint_32)) == 0 &&
3595 bytes_to_jump % (sizeof (png_uint_32)) == 0)
3596 {
3597 png_uint_32p dp32 = png_aligncast(png_uint_32p,dp);
3598 png_const_uint_32p sp32 = png_aligncastconst(
3599 png_const_uint_32p, sp);
3600 size_t skip = (bytes_to_jump-bytes_to_copy) /
3601 (sizeof (png_uint_32));
3602
3603 do
3604 {
3605 size_t c = bytes_to_copy;
3606 do
3607 {
3608 *dp32++ = *sp32++;
3609 c -= (sizeof (png_uint_32));
3610 }
3611 while (c > 0);
3612
3613 if (row_width <= bytes_to_jump)
3614 return;
3615
3616 dp32 += skip;
3617 sp32 += skip;
3618 row_width -= bytes_to_jump;
3619 }
3620 while (bytes_to_copy <= row_width);
3621
3622 /* Get to here when the row_width truncates the final copy.
3623 * There will be 1-3 bytes left to copy, so don't try the
3624 * 16-bit loop below.
3625 */
3626 dp = (png_bytep)dp32;
3627 sp = (png_const_bytep)sp32;
3628 do
3629 *dp++ = *sp++;
3630 while (--row_width > 0);
3631 return;
3632 }
3633
3634 /* Else do it in 16-bit quantities, but only if the size is
3635 * not too large.
3636 */
3637 else
3638 {
3639 png_uint_16p dp16 = png_aligncast(png_uint_16p, dp);
3640 png_const_uint_16p sp16 = png_aligncastconst(
3641 png_const_uint_16p, sp);
3642 size_t skip = (bytes_to_jump-bytes_to_copy) /
3643 (sizeof (png_uint_16));
3644
3645 do
3646 {
3647 size_t c = bytes_to_copy;
3648 do
3649 {
3650 *dp16++ = *sp16++;
3651 c -= (sizeof (png_uint_16));
3652 }
3653 while (c > 0);
3654
3655 if (row_width <= bytes_to_jump)
3656 return;
3657
3658 dp16 += skip;
3659 sp16 += skip;
3660 row_width -= bytes_to_jump;
3661 }
3662 while (bytes_to_copy <= row_width);
3663
3664 /* End of row - 1 byte left, bytes_to_copy > row_width: */
3665 dp = (png_bytep)dp16;
3666 sp = (png_const_bytep)sp16;
3667 do
3668 *dp++ = *sp++;
3669 while (--row_width > 0);
3670 return;
3671 }
3672 }
3673 #endif /* ALIGN_TYPE code */
3674
3675 /* The true default - use a memcpy: */
3676 for (;;)
3677 {
3678 memcpy(dp, sp, bytes_to_copy);
3679
3680 if (row_width <= bytes_to_jump)
3681 return;
3682
3683 sp += bytes_to_jump;
3684 dp += bytes_to_jump;
3685 row_width -= bytes_to_jump;
3686 if (bytes_to_copy > row_width)
3687 bytes_to_copy = (unsigned int)/*SAFE*/row_width;
3688 }
3689 }
3690
3691 /* NOT REACHED*/
3692 } /* pixel_depth >= 8 */
3693
3694 /* Here if pixel_depth < 8 to check 'end_ptr' below. */
3695 }
3696 else
3697 #endif /* READ_INTERLACING */
3698
3699 /* If here then the switch above wasn't used so just memcpy the whole row
3700 * from the temporary row buffer (notice that this overwrites the end of the
3701 * destination row if it is a partial byte.)
3702 */
3703 memcpy(dp, sp, PNG_ROWBYTES(pixel_depth, row_width));
3704
3705 /* Restore the overwritten bits from the last byte if necessary. */
3706 if (end_ptr != NULL)
3707 *end_ptr = (png_byte)((end_byte & end_mask) | (*end_ptr & ~end_mask));
3708 }
3709
3710 #ifdef PNG_READ_INTERLACING_SUPPORTED
3711 void /* PRIVATE */
3712 png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass,
3713 png_uint_32 transformations /* Because these may affect the byte layout */)
3714 {
3715 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
3716 /* Offset to next interlace block */
3717 static const unsigned int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
3718
3719 png_debug(1, "in png_do_read_interlace");
3720 if (row != NULL && row_info != NULL)
3721 {
3722 png_uint_32 final_width;
3723
3724 final_width = row_info->width * png_pass_inc[pass];
3725
3726 switch (row_info->pixel_depth)
3727 {
3728 case 1:
3729 {
3730 png_bytep sp = row + (size_t)((row_info->width - 1) >> 3);
3731 png_bytep dp = row + (size_t)((final_width - 1) >> 3);
3732 unsigned int sshift, dshift;
3733 unsigned int s_start, s_end;
3734 int s_inc;
3735 int jstop = (int)png_pass_inc[pass];
3736 png_byte v;
3737 png_uint_32 i;
3738 int j;
3739
3740 #ifdef PNG_READ_PACKSWAP_SUPPORTED
3741 if ((transformations & PNG_PACKSWAP) != 0)
3742 {
3743 sshift = ((row_info->width + 7) & 0x07);
3744 dshift = ((final_width + 7) & 0x07);
3745 s_start = 7;
3746 s_end = 0;
3747 s_inc = -1;
3748 }
3749
3750 else
3751 #endif
3752 {
3753 sshift = 7 - ((row_info->width + 7) & 0x07);
3754 dshift = 7 - ((final_width + 7) & 0x07);
3755 s_start = 0;
3756 s_end = 7;
3757 s_inc = 1;
3758 }
3759
3760 for (i = 0; i < row_info->width; i++)
3761 {
3762 v = (png_byte)((*sp >> sshift) & 0x01);
3763 for (j = 0; j < jstop; j++)
3764 {
3765 unsigned int tmp = *dp & (0x7f7f >> (7 - dshift));
3766 tmp |= (unsigned int)(v << dshift);
3767 *dp = (png_byte)(tmp & 0xff);
3768
3769 if (dshift == s_end)
3770 {
3771 dshift = s_start;
3772 dp--;
3773 }
3774
3775 else
3776 dshift = (unsigned int)((int)dshift + s_inc);
3777 }
3778
3779 if (sshift == s_end)
3780 {
3781 sshift = s_start;
3782 sp--;
3783 }
3784
3785 else
3786 sshift = (unsigned int)((int)sshift + s_inc);
3787 }
3788 break;
3789 }
3790
3791 case 2:
3792 {
3793 png_bytep sp = row + (png_uint_32)((row_info->width - 1) >> 2);
3794 png_bytep dp = row + (png_uint_32)((final_width - 1) >> 2);
3795 unsigned int sshift, dshift;
3796 unsigned int s_start, s_end;
3797 int s_inc;
3798 int jstop = (int)png_pass_inc[pass];
3799 png_uint_32 i;
3800
3801 #ifdef PNG_READ_PACKSWAP_SUPPORTED
3802 if ((transformations & PNG_PACKSWAP) != 0)
3803 {
3804 sshift = (((row_info->width + 3) & 0x03) << 1);
3805 dshift = (((final_width + 3) & 0x03) << 1);
3806 s_start = 6;
3807 s_end = 0;
3808 s_inc = -2;
3809 }
3810
3811 else
3812 #endif
3813 {
3814 sshift = ((3 - ((row_info->width + 3) & 0x03)) << 1);
3815 dshift = ((3 - ((final_width + 3) & 0x03)) << 1);
3816 s_start = 0;
3817 s_end = 6;
3818 s_inc = 2;
3819 }
3820
3821 for (i = 0; i < row_info->width; i++)
3822 {
3823 png_byte v;
3824 int j;
3825
3826 v = (png_byte)((*sp >> sshift) & 0x03);
3827 for (j = 0; j < jstop; j++)
3828 {
3829 unsigned int tmp = *dp & (0x3f3f >> (6 - dshift));
3830 tmp |= (unsigned int)(v << dshift);
3831 *dp = (png_byte)(tmp & 0xff);
3832
3833 if (dshift == s_end)
3834 {
3835 dshift = s_start;
3836 dp--;
3837 }
3838
3839 else
3840 dshift = (unsigned int)((int)dshift + s_inc);
3841 }
3842
3843 if (sshift == s_end)
3844 {
3845 sshift = s_start;
3846 sp--;
3847 }
3848
3849 else
3850 sshift = (unsigned int)((int)sshift + s_inc);
3851 }
3852 break;
3853 }
3854
3855 case 4:
3856 {
3857 png_bytep sp = row + (size_t)((row_info->width - 1) >> 1);
3858 png_bytep dp = row + (size_t)((final_width - 1) >> 1);
3859 unsigned int sshift, dshift;
3860 unsigned int s_start, s_end;
3861 int s_inc;
3862 png_uint_32 i;
3863 int jstop = (int)png_pass_inc[pass];
3864
3865 #ifdef PNG_READ_PACKSWAP_SUPPORTED
3866 if ((transformations & PNG_PACKSWAP) != 0)
3867 {
3868 sshift = (((row_info->width + 1) & 0x01) << 2);
3869 dshift = (((final_width + 1) & 0x01) << 2);
3870 s_start = 4;
3871 s_end = 0;
3872 s_inc = -4;
3873 }
3874
3875 else
3876 #endif
3877 {
3878 sshift = ((1 - ((row_info->width + 1) & 0x01)) << 2);
3879 dshift = ((1 - ((final_width + 1) & 0x01)) << 2);
3880 s_start = 0;
3881 s_end = 4;
3882 s_inc = 4;
3883 }
3884
3885 for (i = 0; i < row_info->width; i++)
3886 {
3887 png_byte v = (png_byte)((*sp >> sshift) & 0x0f);
3888 int j;
3889
3890 for (j = 0; j < jstop; j++)
3891 {
3892 unsigned int tmp = *dp & (0xf0f >> (4 - dshift));
3893 tmp |= (unsigned int)(v << dshift);
3894 *dp = (png_byte)(tmp & 0xff);
3895
3896 if (dshift == s_end)
3897 {
3898 dshift = s_start;
3899 dp--;
3900 }
3901
3902 else
3903 dshift = (unsigned int)((int)dshift + s_inc);
3904 }
3905
3906 if (sshift == s_end)
3907 {
3908 sshift = s_start;
3909 sp--;
3910 }
3911
3912 else
3913 sshift = (unsigned int)((int)sshift + s_inc);
3914 }
3915 break;
3916 }
3917
3918 default:
3919 {
3920 size_t pixel_bytes = (row_info->pixel_depth >> 3);
3921
3922 png_bytep sp = row + (size_t)(row_info->width - 1)
3923 * pixel_bytes;
3924
3925 png_bytep dp = row + (size_t)(final_width - 1) * pixel_bytes;
3926
3927 int jstop = (int)png_pass_inc[pass];
3928 png_uint_32 i;
3929
3930 for (i = 0; i < row_info->width; i++)
3931 {
3932 png_byte v[8]; /* SAFE; pixel_depth does not exceed 64 */
3933 int j;
3934
3935 memcpy(v, sp, pixel_bytes);
3936
3937 for (j = 0; j < jstop; j++)
3938 {
3939 memcpy(dp, v, pixel_bytes);
3940 dp -= pixel_bytes;
3941 }
3942
3943 sp -= pixel_bytes;
3944 }
3945 break;
3946 }
3947 }
3948
3949 row_info->width = final_width;
3950 row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, final_width);
3951 }
3952 #ifndef PNG_READ_PACKSWAP_SUPPORTED
3953 PNG_UNUSED(transformations) /* Silence compiler warning */
3954 #endif
3955 }
3956 #endif /* READ_INTERLACING */
3957
3958 static void
3959 png_read_filter_row_sub(png_row_infop row_info, png_bytep row,
3960 png_const_bytep prev_row)
3961 {
3962 size_t i;
3963 size_t istop = row_info->rowbytes;
3964 unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
3965 png_bytep rp = row + bpp;
3966
3967 PNG_UNUSED(prev_row)
3968
3969 for (i = bpp; i < istop; i++)
3970 {
3971 *rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 0xff);
3972 rp++;
3973 }
3974 }
3975
3976 static void
3977 png_read_filter_row_up(png_row_infop row_info, png_bytep row,
3978 png_const_bytep prev_row)
3979 {
3980 size_t i;
3981 size_t istop = row_info->rowbytes;
3982 png_bytep rp = row;
3983 png_const_bytep pp = prev_row;
3984
3985 for (i = 0; i < istop; i++)
3986 {
3987 *rp = (png_byte)(((int)(*rp) + (int)(*pp++)) & 0xff);
3988 rp++;
3989 }
3990 }
3991
3992 static void
3993 png_read_filter_row_avg(png_row_infop row_info, png_bytep row,
3994 png_const_bytep prev_row)
3995 {
3996 size_t i;
3997 png_bytep rp = row;
3998 png_const_bytep pp = prev_row;
3999 unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
4000 size_t istop = row_info->rowbytes - bpp;
4001
4002 for (i = 0; i < bpp; i++)
4003 {
4004 *rp = (png_byte)(((int)(*rp) +
4005 ((int)(*pp++) / 2 )) & 0xff);
4006
4007 rp++;
4008 }
4009
4010 for (i = 0; i < istop; i++)
4011 {
4012 *rp = (png_byte)(((int)(*rp) +
4013 (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff);
4014
4015 rp++;
4016 }
4017 }
4018
4019 static void
4020 png_read_filter_row_paeth_1byte_pixel(png_row_infop row_info, png_bytep row,
4021 png_const_bytep prev_row)
4022 {
4023 png_bytep rp_end = row + row_info->rowbytes;
4024 int a, c;
4025
4026 /* First pixel/byte */
4027 c = *prev_row++;
4028 a = *row + c;
4029 *row++ = (png_byte)a;
4030
4031 /* Remainder */
4032 while (row < rp_end)
4033 {
4034 int b, pa, pb, pc, p;
4035
4036 a &= 0xff; /* From previous iteration or start */
4037 b = *prev_row++;
4038
4039 p = b - c;
4040 pc = a - c;
4041
4042 #ifdef PNG_USE_ABS
4043 pa = abs(p);
4044 pb = abs(pc);
4045 pc = abs(p + pc);
4046 #else
4047 pa = p < 0 ? -p : p;
4048 pb = pc < 0 ? -pc : pc;
4049 pc = (p + pc) < 0 ? -(p + pc) : p + pc;
4050 #endif
4051
4052 /* Find the best predictor, the least of pa, pb, pc favoring the earlier
4053 * ones in the case of a tie.
4054 */
4055 if (pb < pa)
4056 {
4057 pa = pb; a = b;
4058 }
4059 if (pc < pa) a = c;
4060
4061 /* Calculate the current pixel in a, and move the previous row pixel to c
4062 * for the next time round the loop
4063 */
4064 c = b;
4065 a += *row;
4066 *row++ = (png_byte)a;
4067 }
4068 }
4069
4070 static void
4071 png_read_filter_row_paeth_multibyte_pixel(png_row_infop row_info, png_bytep row,
4072 png_const_bytep prev_row)
4073 {
4074 unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
4075 png_bytep rp_end = row + bpp;
4076
4077 /* Process the first pixel in the row completely (this is the same as 'up'
4078 * because there is only one candidate predictor for the first row).
4079 */
4080 while (row < rp_end)
4081 {
4082 int a = *row + *prev_row++;
4083 *row++ = (png_byte)a;
4084 }
4085
4086 /* Remainder */
4087 rp_end = rp_end + (row_info->rowbytes - bpp);
4088
4089 while (row < rp_end)
4090 {
4091 int a, b, c, pa, pb, pc, p;
4092
4093 c = *(prev_row - bpp);
4094 a = *(row - bpp);
4095 b = *prev_row++;
4096
4097 p = b - c;
4098 pc = a - c;
4099
4100 #ifdef PNG_USE_ABS
4101 pa = abs(p);
4102 pb = abs(pc);
4103 pc = abs(p + pc);
4104 #else
4105 pa = p < 0 ? -p : p;
4106 pb = pc < 0 ? -pc : pc;
4107 pc = (p + pc) < 0 ? -(p + pc) : p + pc;
4108 #endif
4109
4110 if (pb < pa)
4111 {
4112 pa = pb; a = b;
4113 }
4114 if (pc < pa) a = c;
4115
4116 a += *row;
4117 *row++ = (png_byte)a;
4118 }
4119 }
4120
4121 static void
4122 png_init_filter_functions(png_structrp pp)
4123 /* This function is called once for every PNG image (except for PNG images
4124 * that only use PNG_FILTER_VALUE_NONE for all rows) to set the
4125 * implementations required to reverse the filtering of PNG rows. Reversing
4126 * the filter is the first transformation performed on the row data. It is
4127 * performed in place, therefore an implementation can be selected based on
4128 * the image pixel format. If the implementation depends on image width then
4129 * take care to ensure that it works correctly if the image is interlaced -
4130 * interlacing causes the actual row width to vary.
4131 */
4132 {
4133 unsigned int bpp = (pp->pixel_depth + 7) >> 3;
4134
4135 pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub;
4136 pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up;
4137 pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg;
4138 if (bpp == 1)
4139 pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
4140 png_read_filter_row_paeth_1byte_pixel;
4141 else
4142 pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
4143 png_read_filter_row_paeth_multibyte_pixel;
4144
4145 #ifdef PNG_FILTER_OPTIMIZATIONS
4146 /* To use this define PNG_FILTER_OPTIMIZATIONS as the name of a function to
4147 * call to install hardware optimizations for the above functions; simply
4148 * replace whatever elements of the pp->read_filter[] array with a hardware
4149 * specific (or, for that matter, generic) optimization.
4150 *
4151 * To see an example of this examine what configure.ac does when
4152 * --enable-arm-neon is specified on the command line.
4153 */
4154 PNG_FILTER_OPTIMIZATIONS(pp, bpp);
4155 #endif
4156 }
4157
4158 void /* PRIVATE */
4159 png_read_filter_row(png_structrp pp, png_row_infop row_info, png_bytep row,
4160 png_const_bytep prev_row, int filter)
4161 {
4162 /* OPTIMIZATION: DO NOT MODIFY THIS FUNCTION, instead #define
4163 * PNG_FILTER_OPTIMIZATIONS to a function that overrides the generic
4164 * implementations. See png_init_filter_functions above.
4165 */
4166 if (filter > PNG_FILTER_VALUE_NONE && filter < PNG_FILTER_VALUE_LAST)
4167 {
4168 if (pp->read_filter[0] == NULL)
4169 png_init_filter_functions(pp);
4170
4171 pp->read_filter[filter-1](row_info, row, prev_row);
4172 }
4173 }
4174
4175 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
4176 void /* PRIVATE */
4177 png_read_IDAT_data(png_structrp png_ptr, png_bytep output,
4178 png_alloc_size_t avail_out)
4179 {
4180 /* Loop reading IDATs and decompressing the result into output[avail_out] */
4181 png_ptr->zstream.next_out = output;
4182 png_ptr->zstream.avail_out = 0; /* safety: set below */
4183
4184 if (output == NULL)
4185 avail_out = 0;
4186
4187 do
4188 {
4189 int ret;
4190 png_byte tmpbuf[PNG_INFLATE_BUF_SIZE];
4191
4192 if (png_ptr->zstream.avail_in == 0)
4193 {
4194 uInt avail_in;
4195 png_bytep buffer;
4196
4197 while (png_ptr->idat_size == 0)
4198 {
4199 png_crc_finish(png_ptr, 0);
4200
4201 png_ptr->idat_size = png_read_chunk_header(png_ptr);
4202 /* This is an error even in the 'check' case because the code just
4203 * consumed a non-IDAT header.
4204 */
4205 if (png_ptr->chunk_name != png_IDAT)
4206 png_error(png_ptr, "Not enough image data");
4207 }
4208
4209 avail_in = png_ptr->IDAT_read_size;
4210
4211 if (avail_in > png_ptr->idat_size)
4212 avail_in = (uInt)png_ptr->idat_size;
4213
4214 /* A PNG with a gradually increasing IDAT size will defeat this attempt
4215 * to minimize memory usage by causing lots of re-allocs, but
4216 * realistically doing IDAT_read_size re-allocs is not likely to be a
4217 * big problem.
4218 */
4219 buffer = png_read_buffer(png_ptr, avail_in, 0/*error*/);
4220
4221 png_crc_read(png_ptr, buffer, avail_in);
4222 png_ptr->idat_size -= avail_in;
4223
4224 png_ptr->zstream.next_in = buffer;
4225 png_ptr->zstream.avail_in = avail_in;
4226 }
4227
4228 /* And set up the output side. */
4229 if (output != NULL) /* standard read */
4230 {
4231 uInt out = ZLIB_IO_MAX;
4232
4233 if (out > avail_out)
4234 out = (uInt)avail_out;
4235
4236 avail_out -= out;
4237 png_ptr->zstream.avail_out = out;
4238 }
4239
4240 else /* after last row, checking for end */
4241 {
4242 png_ptr->zstream.next_out = tmpbuf;
4243 png_ptr->zstream.avail_out = (sizeof tmpbuf);
4244 }
4245
4246 /* Use NO_FLUSH; this gives zlib the maximum opportunity to optimize the
4247 * process. If the LZ stream is truncated the sequential reader will
4248 * terminally damage the stream, above, by reading the chunk header of the
4249 * following chunk (it then exits with png_error).
4250 *
4251 * TODO: deal more elegantly with truncated IDAT lists.
4252 */
4253 ret = PNG_INFLATE(png_ptr, Z_NO_FLUSH);
4254
4255 /* Take the unconsumed output back. */
4256 if (output != NULL)
4257 avail_out += png_ptr->zstream.avail_out;
4258
4259 else /* avail_out counts the extra bytes */
4260 avail_out += (sizeof tmpbuf) - png_ptr->zstream.avail_out;
4261
4262 png_ptr->zstream.avail_out = 0;
4263
4264 if (ret == Z_STREAM_END)
4265 {
4266 /* Do this for safety; we won't read any more into this row. */
4267 png_ptr->zstream.next_out = NULL;
4268
4269 png_ptr->mode |= PNG_AFTER_IDAT;
4270 png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
4271
4272 if (png_ptr->zstream.avail_in > 0 || png_ptr->idat_size > 0)
4273 png_chunk_benign_error(png_ptr, "Extra compressed data");
4274 break;
4275 }
4276
4277 if (ret != Z_OK)
4278 {
4279 png_zstream_error(png_ptr, ret);
4280
4281 if (output != NULL)
4282 png_chunk_error(png_ptr, png_ptr->zstream.msg);
4283
4284 else /* checking */
4285 {
4286 png_chunk_benign_error(png_ptr, png_ptr->zstream.msg);
4287 return;
4288 }
4289 }
4290 } while (avail_out > 0);
4291
4292 if (avail_out > 0)
4293 {
4294 /* The stream ended before the image; this is the same as too few IDATs so
4295 * should be handled the same way.
4296 */
4297 if (output != NULL)
4298 png_error(png_ptr, "Not enough image data");
4299
4300 else /* the deflate stream contained extra data */
4301 png_chunk_benign_error(png_ptr, "Too much image data");
4302 }
4303 }
4304
4305 void /* PRIVATE */
4306 png_read_finish_IDAT(png_structrp png_ptr)
4307 {
4308 /* We don't need any more data and the stream should have ended, however the
4309 * LZ end code may actually not have been processed. In this case we must
4310 * read it otherwise stray unread IDAT data or, more likely, an IDAT chunk
4311 * may still remain to be consumed.
4312 */
4313 if ((png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0)
4314 {
4315 /* The NULL causes png_read_IDAT_data to swallow any remaining bytes in
4316 * the compressed stream, but the stream may be damaged too, so even after
4317 * this call we may need to terminate the zstream ownership.
4318 */
4319 png_read_IDAT_data(png_ptr, NULL, 0);
4320 png_ptr->zstream.next_out = NULL; /* safety */
4321
4322 /* Now clear everything out for safety; the following may not have been
4323 * done.
4324 */
4325 if ((png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0)
4326 {
4327 png_ptr->mode |= PNG_AFTER_IDAT;
4328 png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
4329 }
4330 }
4331
4332 /* If the zstream has not been released do it now *and* terminate the reading
4333 * of the final IDAT chunk.
4334 */
4335 if (png_ptr->zowner == png_IDAT)
4336 {
4337 /* Always do this; the pointers otherwise point into the read buffer. */
4338 png_ptr->zstream.next_in = NULL;
4339 png_ptr->zstream.avail_in = 0;
4340
4341 /* Now we no longer own the zstream. */
4342 png_ptr->zowner = 0;
4343
4344 /* The slightly weird semantics of the sequential IDAT reading is that we
4345 * are always in or at the end of an IDAT chunk, so we always need to do a
4346 * crc_finish here. If idat_size is non-zero we also need to read the
4347 * spurious bytes at the end of the chunk now.
4348 */
4349 (void)png_crc_finish(png_ptr, png_ptr->idat_size);
4350 }
4351 }
4352
4353 void /* PRIVATE */
4354 png_read_finish_row(png_structrp png_ptr)
4355 {
4356 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
4357
4358 /* Start of interlace block */
4359 static const png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
4360
4361 /* Offset to next interlace block */
4362 static const png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
4363
4364 /* Start of interlace block in the y direction */
4365 static const png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
4366
4367 /* Offset to next interlace block in the y direction */
4368 static const png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
4369
4370 png_debug(1, "in png_read_finish_row");
4371 png_ptr->row_number++;
4372 if (png_ptr->row_number < png_ptr->num_rows)
4373 return;
4374
4375 if (png_ptr->interlaced != 0)
4376 {
4377 png_ptr->row_number = 0;
4378
4379 /* TO DO: don't do this if prev_row isn't needed (requires
4380 * read-ahead of the next row's filter byte.
4381 */
4382 memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
4383
4384 do
4385 {
4386 png_ptr->pass++;
4387
4388 if (png_ptr->pass >= 7)
4389 break;
4390
4391 png_ptr->iwidth = (png_ptr->width +
4392 png_pass_inc[png_ptr->pass] - 1 -
4393 png_pass_start[png_ptr->pass]) /
4394 png_pass_inc[png_ptr->pass];
4395
4396 if ((png_ptr->transformations & PNG_INTERLACE) == 0)
4397 {
4398 png_ptr->num_rows = (png_ptr->height +
4399 png_pass_yinc[png_ptr->pass] - 1 -
4400 png_pass_ystart[png_ptr->pass]) /
4401 png_pass_yinc[png_ptr->pass];
4402 }
4403
4404 else /* if (png_ptr->transformations & PNG_INTERLACE) */
4405 break; /* libpng deinterlacing sees every row */
4406
4407 } while (png_ptr->num_rows == 0 || png_ptr->iwidth == 0);
4408
4409 if (png_ptr->pass < 7)
4410 return;
4411 }
4412
4413 /* Here after at the end of the last row of the last pass. */
4414 png_read_finish_IDAT(png_ptr);
4415 }
4416 #endif /* SEQUENTIAL_READ */
4417
4418 void /* PRIVATE */
4419 png_read_start_row(png_structrp png_ptr)
4420 {
4421 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
4422
4423 /* Start of interlace block */
4424 static const png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
4425
4426 /* Offset to next interlace block */
4427 static const png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
4428
4429 /* Start of interlace block in the y direction */
4430 static const png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
4431
4432 /* Offset to next interlace block in the y direction */
4433 static const png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
4434
4435 unsigned int max_pixel_depth;
4436 size_t row_bytes;
4437
4438 png_debug(1, "in png_read_start_row");
4439
4440 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
4441 png_init_read_transformations(png_ptr);
4442 #endif
4443 if (png_ptr->interlaced != 0)
4444 {
4445 if ((png_ptr->transformations & PNG_INTERLACE) == 0)
4446 png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 -
4447 png_pass_ystart[0]) / png_pass_yinc[0];
4448
4449 else
4450 png_ptr->num_rows = png_ptr->height;
4451
4452 png_ptr->iwidth = (png_ptr->width +
4453 png_pass_inc[png_ptr->pass] - 1 -
4454 png_pass_start[png_ptr->pass]) /
4455 png_pass_inc[png_ptr->pass];
4456 }
4457
4458 else
4459 {
4460 png_ptr->num_rows = png_ptr->height;
4461 png_ptr->iwidth = png_ptr->width;
4462 }
4463
4464 max_pixel_depth = (unsigned int)png_ptr->pixel_depth;
4465
4466 /* WARNING: * png_read_transform_info (pngrtran.c) performs a simpler set of
4467 * calculations to calculate the final pixel depth, then
4468 * png_do_read_transforms actually does the transforms. This means that the
4469 * code which effectively calculates this value is actually repeated in three
4470 * separate places. They must all match. Innocent changes to the order of
4471 * transformations can and will break libpng in a way that causes memory
4472 * overwrites.
4473 *
4474 * TODO: fix this.
4475 */
4476 #ifdef PNG_READ_PACK_SUPPORTED
4477 if ((png_ptr->transformations & PNG_PACK) != 0 && png_ptr->bit_depth < 8)
4478 max_pixel_depth = 8;
4479 #endif
4480
4481 #ifdef PNG_READ_EXPAND_SUPPORTED
4482 if ((png_ptr->transformations & PNG_EXPAND) != 0)
4483 {
4484 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
4485 {
4486 if (png_ptr->num_trans != 0)
4487 max_pixel_depth = 32;
4488
4489 else
4490 max_pixel_depth = 24;
4491 }
4492
4493 else if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
4494 {
4495 if (max_pixel_depth < 8)
4496 max_pixel_depth = 8;
4497
4498 if (png_ptr->num_trans != 0)
4499 max_pixel_depth *= 2;
4500 }
4501
4502 else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
4503 {
4504 if (png_ptr->num_trans != 0)
4505 {
4506 max_pixel_depth *= 4;
4507 max_pixel_depth /= 3;
4508 }
4509 }
4510 }
4511 #endif
4512
4513 #ifdef PNG_READ_EXPAND_16_SUPPORTED
4514 if ((png_ptr->transformations & PNG_EXPAND_16) != 0)
4515 {
4516 # ifdef PNG_READ_EXPAND_SUPPORTED
4517 /* In fact it is an error if it isn't supported, but checking is
4518 * the safe way.
4519 */
4520 if ((png_ptr->transformations & PNG_EXPAND) != 0)
4521 {
4522 if (png_ptr->bit_depth < 16)
4523 max_pixel_depth *= 2;
4524 }
4525 else
4526 # endif
4527 png_ptr->transformations &= ~PNG_EXPAND_16;
4528 }
4529 #endif
4530
4531 #ifdef PNG_READ_FILLER_SUPPORTED
4532 if ((png_ptr->transformations & (PNG_FILLER)) != 0)
4533 {
4534 if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
4535 {
4536 if (max_pixel_depth <= 8)
4537 max_pixel_depth = 16;
4538
4539 else
4540 max_pixel_depth = 32;
4541 }
4542
4543 else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB ||
4544 png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
4545 {
4546 if (max_pixel_depth <= 32)
4547 max_pixel_depth = 32;
4548
4549 else
4550 max_pixel_depth = 64;
4551 }
4552 }
4553 #endif
4554
4555 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
4556 if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0)
4557 {
4558 if (
4559 #ifdef PNG_READ_EXPAND_SUPPORTED
4560 (png_ptr->num_trans != 0 &&
4561 (png_ptr->transformations & PNG_EXPAND) != 0) ||
4562 #endif
4563 #ifdef PNG_READ_FILLER_SUPPORTED
4564 (png_ptr->transformations & (PNG_FILLER)) != 0 ||
4565 #endif
4566 png_ptr->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
4567 {
4568 if (max_pixel_depth <= 16)
4569 max_pixel_depth = 32;
4570
4571 else
4572 max_pixel_depth = 64;
4573 }
4574
4575 else
4576 {
4577 if (max_pixel_depth <= 8)
4578 {
4579 if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
4580 max_pixel_depth = 32;
4581
4582 else
4583 max_pixel_depth = 24;
4584 }
4585
4586 else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
4587 max_pixel_depth = 64;
4588
4589 else
4590 max_pixel_depth = 48;
4591 }
4592 }
4593 #endif
4594
4595 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) && \
4596 defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
4597 if ((png_ptr->transformations & PNG_USER_TRANSFORM) != 0)
4598 {
4599 unsigned int user_pixel_depth = png_ptr->user_transform_depth *
4600 png_ptr->user_transform_channels;
4601
4602 if (user_pixel_depth > max_pixel_depth)
4603 max_pixel_depth = user_pixel_depth;
4604 }
4605 #endif
4606
4607 /* This value is stored in png_struct and double checked in the row read
4608 * code.
4609 */
4610 png_ptr->maximum_pixel_depth = (png_byte)max_pixel_depth;
4611 png_ptr->transformed_pixel_depth = 0; /* calculated on demand */
4612
4613 /* Align the width on the next larger 8 pixels. Mainly used
4614 * for interlacing
4615 */
4616 row_bytes = ((png_ptr->width + 7) & ~((png_uint_32)7));
4617 /* Calculate the maximum bytes needed, adding a byte and a pixel
4618 * for safety's sake
4619 */
4620 row_bytes = PNG_ROWBYTES(max_pixel_depth, row_bytes) +
4621 1 + ((max_pixel_depth + 7) >> 3U);
4622
4623 #ifdef PNG_MAX_MALLOC_64K
4624 if (row_bytes > (png_uint_32)65536L)
4625 png_error(png_ptr, "This image requires a row greater than 64KB");
4626 #endif
4627
4628 if (row_bytes + 48 > png_ptr->old_big_row_buf_size)
4629 {
4630 png_free(png_ptr, png_ptr->big_row_buf);
4631 png_free(png_ptr, png_ptr->big_prev_row);
4632
4633 if (png_ptr->interlaced != 0)
4634 png_ptr->big_row_buf = (png_bytep)png_calloc(png_ptr,
4635 row_bytes + 48);
4636
4637 else
4638 png_ptr->big_row_buf = (png_bytep)png_malloc(png_ptr, row_bytes + 48);
4639
4640 png_ptr->big_prev_row = (png_bytep)png_malloc(png_ptr, row_bytes + 48);
4641
4642 #ifdef PNG_ALIGNED_MEMORY_SUPPORTED
4643 /* Use 16-byte aligned memory for row_buf with at least 16 bytes
4644 * of padding before and after row_buf; treat prev_row similarly.
4645 * NOTE: the alignment is to the start of the pixels, one beyond the start
4646 * of the buffer, because of the filter byte. Prior to libpng 1.5.6 this
4647 * was incorrect; the filter byte was aligned, which had the exact
4648 * opposite effect of that intended.
4649 */
4650 {
4651 png_bytep temp = png_ptr->big_row_buf + 32;
4652 int extra = (int)((temp - (png_bytep)0) & 0x0f);
4653 png_ptr->row_buf = temp - extra - 1/*filter byte*/;
4654
4655 temp = png_ptr->big_prev_row + 32;
4656 extra = (int)((temp - (png_bytep)0) & 0x0f);
4657 png_ptr->prev_row = temp - extra - 1/*filter byte*/;
4658 }
4659
4660 #else
4661 /* Use 31 bytes of padding before and 17 bytes after row_buf. */
4662 png_ptr->row_buf = png_ptr->big_row_buf + 31;
4663 png_ptr->prev_row = png_ptr->big_prev_row + 31;
4664 #endif
4665 png_ptr->old_big_row_buf_size = row_bytes + 48;
4666 }
4667
4668 #ifdef PNG_MAX_MALLOC_64K
4669 if (png_ptr->rowbytes > 65535)
4670 png_error(png_ptr, "This image requires a row greater than 64KB");
4671
4672 #endif
4673 if (png_ptr->rowbytes > (PNG_SIZE_MAX - 1))
4674 png_error(png_ptr, "Row has too many bytes to allocate in memory");
4675
4676 memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
4677
4678 png_debug1(3, "width = %u,", png_ptr->width);
4679 png_debug1(3, "height = %u,", png_ptr->height);
4680 png_debug1(3, "iwidth = %u,", png_ptr->iwidth);
4681 png_debug1(3, "num_rows = %u,", png_ptr->num_rows);
4682 png_debug1(3, "rowbytes = %lu,", (unsigned long)png_ptr->rowbytes);
4683 png_debug1(3, "irowbytes = %lu",
4684 (unsigned long)PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->iwidth) + 1);
4685
4686 /* The sequential reader needs a buffer for IDAT, but the progressive reader
4687 * does not, so free the read buffer now regardless; the sequential reader
4688 * reallocates it on demand.
4689 */
4690 if (png_ptr->read_buffer != NULL)
4691 {
4692 png_bytep buffer = png_ptr->read_buffer;
4693
4694 png_ptr->read_buffer_size = 0;
4695 png_ptr->read_buffer = NULL;
4696 png_free(png_ptr, buffer);
4697 }
4698
4699 /* Finally claim the zstream for the inflate of the IDAT data, use the bits
4700 * value from the stream (note that this will result in a fatal error if the
4701 * IDAT stream has a bogus deflate header window_bits value, but this should
4702 * not be happening any longer!)
4703 */
4704 if (png_inflate_claim(png_ptr, png_IDAT) != Z_OK)
4705 png_error(png_ptr, png_ptr->zstream.msg);
4706
4707 png_ptr->flags |= PNG_FLAG_ROW_INIT;
4708 }
4709 #endif /* READ */