[LIBPNG] Update to v1.6.21. CORE-11128
[reactos.git] / reactos / dll / 3rdparty / libpng / pngrutil.c
1
2 /* pngrutil.c - utilities to read a PNG file
3 *
4 * Last changed in libpng 1.6.20 [December 3, 2014]
5 * Copyright (c) 1998-2002,2004,2006-2015 Glenn Randers-Pehrson
6 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
7 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
8 *
9 * This code is released under the libpng license.
10 * For conditions of distribution and use, see the disclaimer
11 * and license in png.h
12 *
13 * This file contains routines that are only called from within
14 * libpng itself during the course of reading an image.
15 */
16
17 #include "pngpriv.h"
18
19 #ifdef PNG_READ_SUPPORTED
20
21 png_uint_32 PNGAPI
22 png_get_uint_31(png_const_structrp png_ptr, png_const_bytep buf)
23 {
24 png_uint_32 uval = png_get_uint_32(buf);
25
26 if (uval > PNG_UINT_31_MAX)
27 png_error(png_ptr, "PNG unsigned integer out of range");
28
29 return (uval);
30 }
31
32 #if defined(PNG_READ_gAMA_SUPPORTED) || defined(PNG_READ_cHRM_SUPPORTED)
33 /* The following is a variation on the above for use with the fixed
34 * point values used for gAMA and cHRM. Instead of png_error it
35 * issues a warning and returns (-1) - an invalid value because both
36 * gAMA and cHRM use *unsigned* integers for fixed point values.
37 */
38 #define PNG_FIXED_ERROR (-1)
39
40 static png_fixed_point /* PRIVATE */
41 png_get_fixed_point(png_structrp png_ptr, png_const_bytep buf)
42 {
43 png_uint_32 uval = png_get_uint_32(buf);
44
45 if (uval <= PNG_UINT_31_MAX)
46 return (png_fixed_point)uval; /* known to be in range */
47
48 /* The caller can turn off the warning by passing NULL. */
49 if (png_ptr != NULL)
50 png_warning(png_ptr, "PNG fixed point integer out of range");
51
52 return PNG_FIXED_ERROR;
53 }
54 #endif
55
56 #ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED
57 /* NOTE: the read macros will obscure these definitions, so that if
58 * PNG_USE_READ_MACROS is set the library will not use them internally,
59 * but the APIs will still be available externally.
60 *
61 * The parentheses around "PNGAPI function_name" in the following three
62 * functions are necessary because they allow the macros to co-exist with
63 * these (unused but exported) functions.
64 */
65
66 /* Grab an unsigned 32-bit integer from a buffer in big-endian format. */
67 png_uint_32 (PNGAPI
68 png_get_uint_32)(png_const_bytep buf)
69 {
70 png_uint_32 uval =
71 ((png_uint_32)(*(buf )) << 24) +
72 ((png_uint_32)(*(buf + 1)) << 16) +
73 ((png_uint_32)(*(buf + 2)) << 8) +
74 ((png_uint_32)(*(buf + 3)) ) ;
75
76 return uval;
77 }
78
79 /* Grab a signed 32-bit integer from a buffer in big-endian format. The
80 * data is stored in the PNG file in two's complement format and there
81 * is no guarantee that a 'png_int_32' is exactly 32 bits, therefore
82 * the following code does a two's complement to native conversion.
83 */
84 png_int_32 (PNGAPI
85 png_get_int_32)(png_const_bytep buf)
86 {
87 png_uint_32 uval = png_get_uint_32(buf);
88 if ((uval & 0x80000000) == 0) /* non-negative */
89 return uval;
90
91 uval = (uval ^ 0xffffffff) + 1; /* 2's complement: -x = ~x+1 */
92 if ((uval & 0x80000000) == 0) /* no overflow */
93 return -(png_int_32)uval;
94 /* The following has to be safe; this function only gets called on PNG data
95 * and if we get here that data is invalid. 0 is the most safe value and
96 * if not then an attacker would surely just generate a PNG with 0 instead.
97 */
98 return 0;
99 }
100
101 /* Grab an unsigned 16-bit integer from a buffer in big-endian format. */
102 png_uint_16 (PNGAPI
103 png_get_uint_16)(png_const_bytep buf)
104 {
105 /* ANSI-C requires an int value to accomodate at least 16 bits so this
106 * works and allows the compiler not to worry about possible narrowing
107 * on 32-bit systems. (Pre-ANSI systems did not make integers smaller
108 * than 16 bits either.)
109 */
110 unsigned int val =
111 ((unsigned int)(*buf) << 8) +
112 ((unsigned int)(*(buf + 1)));
113
114 return (png_uint_16)val;
115 }
116
117 #endif /* READ_INT_FUNCTIONS */
118
119 /* Read and check the PNG file signature */
120 void /* PRIVATE */
121 png_read_sig(png_structrp png_ptr, png_inforp info_ptr)
122 {
123 png_size_t num_checked, num_to_check;
124
125 /* Exit if the user application does not expect a signature. */
126 if (png_ptr->sig_bytes >= 8)
127 return;
128
129 num_checked = png_ptr->sig_bytes;
130 num_to_check = 8 - num_checked;
131
132 #ifdef PNG_IO_STATE_SUPPORTED
133 png_ptr->io_state = PNG_IO_READING | PNG_IO_SIGNATURE;
134 #endif
135
136 /* The signature must be serialized in a single I/O call. */
137 png_read_data(png_ptr, &(info_ptr->signature[num_checked]), num_to_check);
138 png_ptr->sig_bytes = 8;
139
140 if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check) != 0)
141 {
142 if (num_checked < 4 &&
143 png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))
144 png_error(png_ptr, "Not a PNG file");
145 else
146 png_error(png_ptr, "PNG file corrupted by ASCII conversion");
147 }
148 if (num_checked < 3)
149 png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
150 }
151
152 /* Read the chunk header (length + type name).
153 * Put the type name into png_ptr->chunk_name, and return the length.
154 */
155 png_uint_32 /* PRIVATE */
156 png_read_chunk_header(png_structrp png_ptr)
157 {
158 png_byte buf[8];
159 png_uint_32 length;
160
161 #ifdef PNG_IO_STATE_SUPPORTED
162 png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_HDR;
163 #endif
164
165 /* Read the length and the chunk name.
166 * This must be performed in a single I/O call.
167 */
168 png_read_data(png_ptr, buf, 8);
169 length = png_get_uint_31(png_ptr, buf);
170
171 /* Put the chunk name into png_ptr->chunk_name. */
172 png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(buf+4);
173
174 png_debug2(0, "Reading %lx chunk, length = %lu",
175 (unsigned long)png_ptr->chunk_name, (unsigned long)length);
176
177 /* Reset the crc and run it over the chunk name. */
178 png_reset_crc(png_ptr);
179 png_calculate_crc(png_ptr, buf + 4, 4);
180
181 /* Check to see if chunk name is valid. */
182 png_check_chunk_name(png_ptr, png_ptr->chunk_name);
183
184 #ifdef PNG_IO_STATE_SUPPORTED
185 png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_DATA;
186 #endif
187
188 return length;
189 }
190
191 /* Read data, and (optionally) run it through the CRC. */
192 void /* PRIVATE */
193 png_crc_read(png_structrp png_ptr, png_bytep buf, png_uint_32 length)
194 {
195 if (png_ptr == NULL)
196 return;
197
198 png_read_data(png_ptr, buf, length);
199 png_calculate_crc(png_ptr, buf, length);
200 }
201
202 /* Optionally skip data and then check the CRC. Depending on whether we
203 * are reading an ancillary or critical chunk, and how the program has set
204 * things up, we may calculate the CRC on the data and print a message.
205 * Returns '1' if there was a CRC error, '0' otherwise.
206 */
207 int /* PRIVATE */
208 png_crc_finish(png_structrp png_ptr, png_uint_32 skip)
209 {
210 /* The size of the local buffer for inflate is a good guess as to a
211 * reasonable size to use for buffering reads from the application.
212 */
213 while (skip > 0)
214 {
215 png_uint_32 len;
216 png_byte tmpbuf[PNG_INFLATE_BUF_SIZE];
217
218 len = (sizeof tmpbuf);
219 if (len > skip)
220 len = skip;
221 skip -= len;
222
223 png_crc_read(png_ptr, tmpbuf, len);
224 }
225
226 if (png_crc_error(png_ptr) != 0)
227 {
228 if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name) != 0 ?
229 (png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) == 0 :
230 (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_USE) != 0)
231 {
232 png_chunk_warning(png_ptr, "CRC error");
233 }
234
235 else
236 png_chunk_error(png_ptr, "CRC error");
237
238 return (1);
239 }
240
241 return (0);
242 }
243
244 /* Compare the CRC stored in the PNG file with that calculated by libpng from
245 * the data it has read thus far.
246 */
247 int /* PRIVATE */
248 png_crc_error(png_structrp png_ptr)
249 {
250 png_byte crc_bytes[4];
251 png_uint_32 crc;
252 int need_crc = 1;
253
254 if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name) != 0)
255 {
256 if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) ==
257 (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN))
258 need_crc = 0;
259 }
260
261 else /* critical */
262 {
263 if ((png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE) != 0)
264 need_crc = 0;
265 }
266
267 #ifdef PNG_IO_STATE_SUPPORTED
268 png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_CRC;
269 #endif
270
271 /* The chunk CRC must be serialized in a single I/O call. */
272 png_read_data(png_ptr, crc_bytes, 4);
273
274 if (need_crc != 0)
275 {
276 crc = png_get_uint_32(crc_bytes);
277 return ((int)(crc != png_ptr->crc));
278 }
279
280 else
281 return (0);
282 }
283
284 #if defined(PNG_READ_iCCP_SUPPORTED) || defined(PNG_READ_iTXt_SUPPORTED) ||\
285 defined(PNG_READ_pCAL_SUPPORTED) || defined(PNG_READ_sCAL_SUPPORTED) ||\
286 defined(PNG_READ_sPLT_SUPPORTED) || defined(PNG_READ_tEXt_SUPPORTED) ||\
287 defined(PNG_READ_zTXt_SUPPORTED) || defined(PNG_SEQUENTIAL_READ_SUPPORTED)
288 /* Manage the read buffer; this simply reallocates the buffer if it is not small
289 * enough (or if it is not allocated). The routine returns a pointer to the
290 * buffer; if an error occurs and 'warn' is set the routine returns NULL, else
291 * it will call png_error (via png_malloc) on failure. (warn == 2 means
292 * 'silent').
293 */
294 static png_bytep
295 png_read_buffer(png_structrp png_ptr, png_alloc_size_t new_size, int warn)
296 {
297 png_bytep buffer = png_ptr->read_buffer;
298
299 if (buffer != NULL && new_size > png_ptr->read_buffer_size)
300 {
301 png_ptr->read_buffer = NULL;
302 png_ptr->read_buffer = NULL;
303 png_ptr->read_buffer_size = 0;
304 png_free(png_ptr, buffer);
305 buffer = NULL;
306 }
307
308 if (buffer == NULL)
309 {
310 buffer = png_voidcast(png_bytep, png_malloc_base(png_ptr, new_size));
311
312 if (buffer != NULL)
313 {
314 png_ptr->read_buffer = buffer;
315 png_ptr->read_buffer_size = new_size;
316 }
317
318 else if (warn < 2) /* else silent */
319 {
320 if (warn != 0)
321 png_chunk_warning(png_ptr, "insufficient memory to read chunk");
322
323 else
324 png_chunk_error(png_ptr, "insufficient memory to read chunk");
325 }
326 }
327
328 return buffer;
329 }
330 #endif /* READ_iCCP|iTXt|pCAL|sCAL|sPLT|tEXt|zTXt|SEQUENTIAL_READ */
331
332 /* png_inflate_claim: claim the zstream for some nefarious purpose that involves
333 * decompression. Returns Z_OK on success, else a zlib error code. It checks
334 * the owner but, in final release builds, just issues a warning if some other
335 * chunk apparently owns the stream. Prior to release it does a png_error.
336 */
337 static int
338 png_inflate_claim(png_structrp png_ptr, png_uint_32 owner)
339 {
340 if (png_ptr->zowner != 0)
341 {
342 char msg[64];
343
344 PNG_STRING_FROM_CHUNK(msg, png_ptr->zowner);
345 /* So the message that results is "<chunk> using zstream"; this is an
346 * internal error, but is very useful for debugging. i18n requirements
347 * are minimal.
348 */
349 (void)png_safecat(msg, (sizeof msg), 4, " using zstream");
350 #if PNG_RELEASE_BUILD
351 png_chunk_warning(png_ptr, msg);
352 png_ptr->zowner = 0;
353 #else
354 png_chunk_error(png_ptr, msg);
355 #endif
356 }
357
358 /* Implementation note: unlike 'png_deflate_claim' this internal function
359 * does not take the size of the data as an argument. Some efficiency could
360 * be gained by using this when it is known *if* the zlib stream itself does
361 * not record the number; however, this is an illusion: the original writer
362 * of the PNG may have selected a lower window size, and we really must
363 * follow that because, for systems with with limited capabilities, we
364 * would otherwise reject the application's attempts to use a smaller window
365 * size (zlib doesn't have an interface to say "this or lower"!).
366 *
367 * inflateReset2 was added to zlib 1.2.4; before this the window could not be
368 * reset, therefore it is necessary to always allocate the maximum window
369 * size with earlier zlibs just in case later compressed chunks need it.
370 */
371 {
372 int ret; /* zlib return code */
373 #if PNG_ZLIB_VERNUM >= 0x1240
374
375 # if defined(PNG_SET_OPTION_SUPPORTED) && defined(PNG_MAXIMUM_INFLATE_WINDOW)
376 int window_bits;
377
378 if (((png_ptr->options >> PNG_MAXIMUM_INFLATE_WINDOW) & 3) ==
379 PNG_OPTION_ON)
380 {
381 window_bits = 15;
382 png_ptr->zstream_start = 0; /* fixed window size */
383 }
384
385 else
386 {
387 window_bits = 0;
388 png_ptr->zstream_start = 1;
389 }
390 # else
391 # define window_bits 0
392 # endif
393 #endif
394
395 /* Set this for safety, just in case the previous owner left pointers to
396 * memory allocations.
397 */
398 png_ptr->zstream.next_in = NULL;
399 png_ptr->zstream.avail_in = 0;
400 png_ptr->zstream.next_out = NULL;
401 png_ptr->zstream.avail_out = 0;
402
403 if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0)
404 {
405 #if PNG_ZLIB_VERNUM < 0x1240
406 ret = inflateReset(&png_ptr->zstream);
407 #else
408 ret = inflateReset2(&png_ptr->zstream, window_bits);
409 #endif
410 }
411
412 else
413 {
414 #if PNG_ZLIB_VERNUM < 0x1240
415 ret = inflateInit(&png_ptr->zstream);
416 #else
417 ret = inflateInit2(&png_ptr->zstream, window_bits);
418 #endif
419
420 if (ret == Z_OK)
421 png_ptr->flags |= PNG_FLAG_ZSTREAM_INITIALIZED;
422 }
423
424 if (ret == Z_OK)
425 png_ptr->zowner = owner;
426
427 else
428 png_zstream_error(png_ptr, ret);
429
430 return ret;
431 }
432
433 #ifdef window_bits
434 # undef window_bits
435 #endif
436 }
437
438 #if PNG_ZLIB_VERNUM >= 0x1240
439 /* Handle the start of the inflate stream if we called inflateInit2(strm,0);
440 * in this case some zlib versions skip validation of the CINFO field and, in
441 * certain circumstances, libpng may end up displaying an invalid image, in
442 * contrast to implementations that call zlib in the normal way (e.g. libpng
443 * 1.5).
444 */
445 int /* PRIVATE */
446 png_zlib_inflate(png_structrp png_ptr, int flush)
447 {
448 if (png_ptr->zstream_start && png_ptr->zstream.avail_in > 0)
449 {
450 if ((*png_ptr->zstream.next_in >> 4) > 7)
451 {
452 png_ptr->zstream.msg = "invalid window size (libpng)";
453 return Z_DATA_ERROR;
454 }
455
456 png_ptr->zstream_start = 0;
457 }
458
459 return inflate(&png_ptr->zstream, flush);
460 }
461 #endif /* Zlib >= 1.2.4 */
462
463 #ifdef PNG_READ_COMPRESSED_TEXT_SUPPORTED
464 /* png_inflate now returns zlib error codes including Z_OK and Z_STREAM_END to
465 * allow the caller to do multiple calls if required. If the 'finish' flag is
466 * set Z_FINISH will be passed to the final inflate() call and Z_STREAM_END must
467 * be returned or there has been a problem, otherwise Z_SYNC_FLUSH is used and
468 * Z_OK or Z_STREAM_END will be returned on success.
469 *
470 * The input and output sizes are updated to the actual amounts of data consumed
471 * or written, not the amount available (as in a z_stream). The data pointers
472 * are not changed, so the next input is (data+input_size) and the next
473 * available output is (output+output_size).
474 */
475 static int
476 png_inflate(png_structrp png_ptr, png_uint_32 owner, int finish,
477 /* INPUT: */ png_const_bytep input, png_uint_32p input_size_ptr,
478 /* OUTPUT: */ png_bytep output, png_alloc_size_t *output_size_ptr)
479 {
480 if (png_ptr->zowner == owner) /* Else not claimed */
481 {
482 int ret;
483 png_alloc_size_t avail_out = *output_size_ptr;
484 png_uint_32 avail_in = *input_size_ptr;
485
486 /* zlib can't necessarily handle more than 65535 bytes at once (i.e. it
487 * can't even necessarily handle 65536 bytes) because the type uInt is
488 * "16 bits or more". Consequently it is necessary to chunk the input to
489 * zlib. This code uses ZLIB_IO_MAX, from pngpriv.h, as the maximum (the
490 * maximum value that can be stored in a uInt.) It is possible to set
491 * ZLIB_IO_MAX to a lower value in pngpriv.h and this may sometimes have
492 * a performance advantage, because it reduces the amount of data accessed
493 * at each step and that may give the OS more time to page it in.
494 */
495 png_ptr->zstream.next_in = PNGZ_INPUT_CAST(input);
496 /* avail_in and avail_out are set below from 'size' */
497 png_ptr->zstream.avail_in = 0;
498 png_ptr->zstream.avail_out = 0;
499
500 /* Read directly into the output if it is available (this is set to
501 * a local buffer below if output is NULL).
502 */
503 if (output != NULL)
504 png_ptr->zstream.next_out = output;
505
506 do
507 {
508 uInt avail;
509 Byte local_buffer[PNG_INFLATE_BUF_SIZE];
510
511 /* zlib INPUT BUFFER */
512 /* The setting of 'avail_in' used to be outside the loop; by setting it
513 * inside it is possible to chunk the input to zlib and simply rely on
514 * zlib to advance the 'next_in' pointer. This allows arbitrary
515 * amounts of data to be passed through zlib at the unavoidable cost of
516 * requiring a window save (memcpy of up to 32768 output bytes)
517 * every ZLIB_IO_MAX input bytes.
518 */
519 avail_in += png_ptr->zstream.avail_in; /* not consumed last time */
520
521 avail = ZLIB_IO_MAX;
522
523 if (avail_in < avail)
524 avail = (uInt)avail_in; /* safe: < than ZLIB_IO_MAX */
525
526 avail_in -= avail;
527 png_ptr->zstream.avail_in = avail;
528
529 /* zlib OUTPUT BUFFER */
530 avail_out += png_ptr->zstream.avail_out; /* not written last time */
531
532 avail = ZLIB_IO_MAX; /* maximum zlib can process */
533
534 if (output == NULL)
535 {
536 /* Reset the output buffer each time round if output is NULL and
537 * make available the full buffer, up to 'remaining_space'
538 */
539 png_ptr->zstream.next_out = local_buffer;
540 if ((sizeof local_buffer) < avail)
541 avail = (sizeof local_buffer);
542 }
543
544 if (avail_out < avail)
545 avail = (uInt)avail_out; /* safe: < ZLIB_IO_MAX */
546
547 png_ptr->zstream.avail_out = avail;
548 avail_out -= avail;
549
550 /* zlib inflate call */
551 /* In fact 'avail_out' may be 0 at this point, that happens at the end
552 * of the read when the final LZ end code was not passed at the end of
553 * the previous chunk of input data. Tell zlib if we have reached the
554 * end of the output buffer.
555 */
556 ret = PNG_INFLATE(png_ptr, avail_out > 0 ? Z_NO_FLUSH :
557 (finish ? Z_FINISH : Z_SYNC_FLUSH));
558 } while (ret == Z_OK);
559
560 /* For safety kill the local buffer pointer now */
561 if (output == NULL)
562 png_ptr->zstream.next_out = NULL;
563
564 /* Claw back the 'size' and 'remaining_space' byte counts. */
565 avail_in += png_ptr->zstream.avail_in;
566 avail_out += png_ptr->zstream.avail_out;
567
568 /* Update the input and output sizes; the updated values are the amount
569 * consumed or written, effectively the inverse of what zlib uses.
570 */
571 if (avail_out > 0)
572 *output_size_ptr -= avail_out;
573
574 if (avail_in > 0)
575 *input_size_ptr -= avail_in;
576
577 /* Ensure png_ptr->zstream.msg is set (even in the success case!) */
578 png_zstream_error(png_ptr, ret);
579 return ret;
580 }
581
582 else
583 {
584 /* This is a bad internal error. The recovery assigns to the zstream msg
585 * pointer, which is not owned by the caller, but this is safe; it's only
586 * used on errors!
587 */
588 png_ptr->zstream.msg = PNGZ_MSG_CAST("zstream unclaimed");
589 return Z_STREAM_ERROR;
590 }
591 }
592
593 /*
594 * Decompress trailing data in a chunk. The assumption is that read_buffer
595 * points at an allocated area holding the contents of a chunk with a
596 * trailing compressed part. What we get back is an allocated area
597 * holding the original prefix part and an uncompressed version of the
598 * trailing part (the malloc area passed in is freed).
599 */
600 static int
601 png_decompress_chunk(png_structrp png_ptr,
602 png_uint_32 chunklength, png_uint_32 prefix_size,
603 png_alloc_size_t *newlength /* must be initialized to the maximum! */,
604 int terminate /*add a '\0' to the end of the uncompressed data*/)
605 {
606 /* TODO: implement different limits for different types of chunk.
607 *
608 * The caller supplies *newlength set to the maximum length of the
609 * uncompressed data, but this routine allocates space for the prefix and
610 * maybe a '\0' terminator too. We have to assume that 'prefix_size' is
611 * limited only by the maximum chunk size.
612 */
613 png_alloc_size_t limit = PNG_SIZE_MAX;
614
615 # ifdef PNG_SET_USER_LIMITS_SUPPORTED
616 if (png_ptr->user_chunk_malloc_max > 0 &&
617 png_ptr->user_chunk_malloc_max < limit)
618 limit = png_ptr->user_chunk_malloc_max;
619 # elif PNG_USER_CHUNK_MALLOC_MAX > 0
620 if (PNG_USER_CHUNK_MALLOC_MAX < limit)
621 limit = PNG_USER_CHUNK_MALLOC_MAX;
622 # endif
623
624 if (limit >= prefix_size + (terminate != 0))
625 {
626 int ret;
627
628 limit -= prefix_size + (terminate != 0);
629
630 if (limit < *newlength)
631 *newlength = limit;
632
633 /* Now try to claim the stream. */
634 ret = png_inflate_claim(png_ptr, png_ptr->chunk_name);
635
636 if (ret == Z_OK)
637 {
638 png_uint_32 lzsize = chunklength - prefix_size;
639
640 ret = png_inflate(png_ptr, png_ptr->chunk_name, 1/*finish*/,
641 /* input: */ png_ptr->read_buffer + prefix_size, &lzsize,
642 /* output: */ NULL, newlength);
643
644 if (ret == Z_STREAM_END)
645 {
646 /* Use 'inflateReset' here, not 'inflateReset2' because this
647 * preserves the previously decided window size (otherwise it would
648 * be necessary to store the previous window size.) In practice
649 * this doesn't matter anyway, because png_inflate will call inflate
650 * with Z_FINISH in almost all cases, so the window will not be
651 * maintained.
652 */
653 if (inflateReset(&png_ptr->zstream) == Z_OK)
654 {
655 /* Because of the limit checks above we know that the new,
656 * expanded, size will fit in a size_t (let alone an
657 * png_alloc_size_t). Use png_malloc_base here to avoid an
658 * extra OOM message.
659 */
660 png_alloc_size_t new_size = *newlength;
661 png_alloc_size_t buffer_size = prefix_size + new_size +
662 (terminate != 0);
663 png_bytep text = png_voidcast(png_bytep, png_malloc_base(png_ptr,
664 buffer_size));
665
666 if (text != NULL)
667 {
668 ret = png_inflate(png_ptr, png_ptr->chunk_name, 1/*finish*/,
669 png_ptr->read_buffer + prefix_size, &lzsize,
670 text + prefix_size, newlength);
671
672 if (ret == Z_STREAM_END)
673 {
674 if (new_size == *newlength)
675 {
676 if (terminate != 0)
677 text[prefix_size + *newlength] = 0;
678
679 if (prefix_size > 0)
680 memcpy(text, png_ptr->read_buffer, prefix_size);
681
682 {
683 png_bytep old_ptr = png_ptr->read_buffer;
684
685 png_ptr->read_buffer = text;
686 png_ptr->read_buffer_size = buffer_size;
687 text = old_ptr; /* freed below */
688 }
689 }
690
691 else
692 {
693 /* The size changed on the second read, there can be no
694 * guarantee that anything is correct at this point.
695 * The 'msg' pointer has been set to "unexpected end of
696 * LZ stream", which is fine, but return an error code
697 * that the caller won't accept.
698 */
699 ret = PNG_UNEXPECTED_ZLIB_RETURN;
700 }
701 }
702
703 else if (ret == Z_OK)
704 ret = PNG_UNEXPECTED_ZLIB_RETURN; /* for safety */
705
706 /* Free the text pointer (this is the old read_buffer on
707 * success)
708 */
709 png_free(png_ptr, text);
710
711 /* This really is very benign, but it's still an error because
712 * the extra space may otherwise be used as a Trojan Horse.
713 */
714 if (ret == Z_STREAM_END &&
715 chunklength - prefix_size != lzsize)
716 png_chunk_benign_error(png_ptr, "extra compressed data");
717 }
718
719 else
720 {
721 /* Out of memory allocating the buffer */
722 ret = Z_MEM_ERROR;
723 png_zstream_error(png_ptr, Z_MEM_ERROR);
724 }
725 }
726
727 else
728 {
729 /* inflateReset failed, store the error message */
730 png_zstream_error(png_ptr, ret);
731
732 if (ret == Z_STREAM_END)
733 ret = PNG_UNEXPECTED_ZLIB_RETURN;
734 }
735 }
736
737 else if (ret == Z_OK)
738 ret = PNG_UNEXPECTED_ZLIB_RETURN;
739
740 /* Release the claimed stream */
741 png_ptr->zowner = 0;
742 }
743
744 else /* the claim failed */ if (ret == Z_STREAM_END) /* impossible! */
745 ret = PNG_UNEXPECTED_ZLIB_RETURN;
746
747 return ret;
748 }
749
750 else
751 {
752 /* Application/configuration limits exceeded */
753 png_zstream_error(png_ptr, Z_MEM_ERROR);
754 return Z_MEM_ERROR;
755 }
756 }
757 #endif /* READ_COMPRESSED_TEXT */
758
759 #ifdef PNG_READ_iCCP_SUPPORTED
760 /* Perform a partial read and decompress, producing 'avail_out' bytes and
761 * reading from the current chunk as required.
762 */
763 static int
764 png_inflate_read(png_structrp png_ptr, png_bytep read_buffer, uInt read_size,
765 png_uint_32p chunk_bytes, png_bytep next_out, png_alloc_size_t *out_size,
766 int finish)
767 {
768 if (png_ptr->zowner == png_ptr->chunk_name)
769 {
770 int ret;
771
772 /* next_in and avail_in must have been initialized by the caller. */
773 png_ptr->zstream.next_out = next_out;
774 png_ptr->zstream.avail_out = 0; /* set in the loop */
775
776 do
777 {
778 if (png_ptr->zstream.avail_in == 0)
779 {
780 if (read_size > *chunk_bytes)
781 read_size = (uInt)*chunk_bytes;
782 *chunk_bytes -= read_size;
783
784 if (read_size > 0)
785 png_crc_read(png_ptr, read_buffer, read_size);
786
787 png_ptr->zstream.next_in = read_buffer;
788 png_ptr->zstream.avail_in = read_size;
789 }
790
791 if (png_ptr->zstream.avail_out == 0)
792 {
793 uInt avail = ZLIB_IO_MAX;
794 if (avail > *out_size)
795 avail = (uInt)*out_size;
796 *out_size -= avail;
797
798 png_ptr->zstream.avail_out = avail;
799 }
800
801 /* Use Z_SYNC_FLUSH when there is no more chunk data to ensure that all
802 * the available output is produced; this allows reading of truncated
803 * streams.
804 */
805 ret = PNG_INFLATE(png_ptr,
806 *chunk_bytes > 0 ? Z_NO_FLUSH : (finish ? Z_FINISH : Z_SYNC_FLUSH));
807 }
808 while (ret == Z_OK && (*out_size > 0 || png_ptr->zstream.avail_out > 0));
809
810 *out_size += png_ptr->zstream.avail_out;
811 png_ptr->zstream.avail_out = 0; /* Should not be required, but is safe */
812
813 /* Ensure the error message pointer is always set: */
814 png_zstream_error(png_ptr, ret);
815 return ret;
816 }
817
818 else
819 {
820 png_ptr->zstream.msg = PNGZ_MSG_CAST("zstream unclaimed");
821 return Z_STREAM_ERROR;
822 }
823 }
824 #endif
825
826 /* Read and check the IDHR chunk */
827
828 void /* PRIVATE */
829 png_handle_IHDR(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
830 {
831 png_byte buf[13];
832 png_uint_32 width, height;
833 int bit_depth, color_type, compression_type, filter_type;
834 int interlace_type;
835
836 png_debug(1, "in png_handle_IHDR");
837
838 if ((png_ptr->mode & PNG_HAVE_IHDR) != 0)
839 png_chunk_error(png_ptr, "out of place");
840
841 /* Check the length */
842 if (length != 13)
843 png_chunk_error(png_ptr, "invalid");
844
845 png_ptr->mode |= PNG_HAVE_IHDR;
846
847 png_crc_read(png_ptr, buf, 13);
848 png_crc_finish(png_ptr, 0);
849
850 width = png_get_uint_31(png_ptr, buf);
851 height = png_get_uint_31(png_ptr, buf + 4);
852 bit_depth = buf[8];
853 color_type = buf[9];
854 compression_type = buf[10];
855 filter_type = buf[11];
856 interlace_type = buf[12];
857
858 /* Set internal variables */
859 png_ptr->width = width;
860 png_ptr->height = height;
861 png_ptr->bit_depth = (png_byte)bit_depth;
862 png_ptr->interlaced = (png_byte)interlace_type;
863 png_ptr->color_type = (png_byte)color_type;
864 #ifdef PNG_MNG_FEATURES_SUPPORTED
865 png_ptr->filter_type = (png_byte)filter_type;
866 #endif
867 png_ptr->compression_type = (png_byte)compression_type;
868
869 /* Find number of channels */
870 switch (png_ptr->color_type)
871 {
872 default: /* invalid, png_set_IHDR calls png_error */
873 case PNG_COLOR_TYPE_GRAY:
874 case PNG_COLOR_TYPE_PALETTE:
875 png_ptr->channels = 1;
876 break;
877
878 case PNG_COLOR_TYPE_RGB:
879 png_ptr->channels = 3;
880 break;
881
882 case PNG_COLOR_TYPE_GRAY_ALPHA:
883 png_ptr->channels = 2;
884 break;
885
886 case PNG_COLOR_TYPE_RGB_ALPHA:
887 png_ptr->channels = 4;
888 break;
889 }
890
891 /* Set up other useful info */
892 png_ptr->pixel_depth = (png_byte)(png_ptr->bit_depth * png_ptr->channels);
893 png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->width);
894 png_debug1(3, "bit_depth = %d", png_ptr->bit_depth);
895 png_debug1(3, "channels = %d", png_ptr->channels);
896 png_debug1(3, "rowbytes = %lu", (unsigned long)png_ptr->rowbytes);
897 png_set_IHDR(png_ptr, info_ptr, width, height, bit_depth,
898 color_type, interlace_type, compression_type, filter_type);
899 }
900
901 /* Read and check the palette */
902 void /* PRIVATE */
903 png_handle_PLTE(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
904 {
905 png_color palette[PNG_MAX_PALETTE_LENGTH];
906 int max_palette_length, num, i;
907 #ifdef PNG_POINTER_INDEXING_SUPPORTED
908 png_colorp pal_ptr;
909 #endif
910
911 png_debug(1, "in png_handle_PLTE");
912
913 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
914 png_chunk_error(png_ptr, "missing IHDR");
915
916 /* Moved to before the 'after IDAT' check below because otherwise duplicate
917 * PLTE chunks are potentially ignored (the spec says there shall not be more
918 * than one PLTE, the error is not treated as benign, so this check trumps
919 * the requirement that PLTE appears before IDAT.)
920 */
921 else if ((png_ptr->mode & PNG_HAVE_PLTE) != 0)
922 png_chunk_error(png_ptr, "duplicate");
923
924 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
925 {
926 /* This is benign because the non-benign error happened before, when an
927 * IDAT was encountered in a color-mapped image with no PLTE.
928 */
929 png_crc_finish(png_ptr, length);
930 png_chunk_benign_error(png_ptr, "out of place");
931 return;
932 }
933
934 png_ptr->mode |= PNG_HAVE_PLTE;
935
936 if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0)
937 {
938 png_crc_finish(png_ptr, length);
939 png_chunk_benign_error(png_ptr, "ignored in grayscale PNG");
940 return;
941 }
942
943 #ifndef PNG_READ_OPT_PLTE_SUPPORTED
944 if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
945 {
946 png_crc_finish(png_ptr, length);
947 return;
948 }
949 #endif
950
951 if (length > 3*PNG_MAX_PALETTE_LENGTH || length % 3)
952 {
953 png_crc_finish(png_ptr, length);
954
955 if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
956 png_chunk_benign_error(png_ptr, "invalid");
957
958 else
959 png_chunk_error(png_ptr, "invalid");
960
961 return;
962 }
963
964 /* The cast is safe because 'length' is less than 3*PNG_MAX_PALETTE_LENGTH */
965 num = (int)length / 3;
966
967 /* If the palette has 256 or fewer entries but is too large for the bit
968 * depth, we don't issue an error, to preserve the behavior of previous
969 * libpng versions. We silently truncate the unused extra palette entries
970 * here.
971 */
972 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
973 max_palette_length = (1 << png_ptr->bit_depth);
974 else
975 max_palette_length = PNG_MAX_PALETTE_LENGTH;
976
977 if (num > max_palette_length)
978 num = max_palette_length;
979
980 #ifdef PNG_POINTER_INDEXING_SUPPORTED
981 for (i = 0, pal_ptr = palette; i < num; i++, pal_ptr++)
982 {
983 png_byte buf[3];
984
985 png_crc_read(png_ptr, buf, 3);
986 pal_ptr->red = buf[0];
987 pal_ptr->green = buf[1];
988 pal_ptr->blue = buf[2];
989 }
990 #else
991 for (i = 0; i < num; i++)
992 {
993 png_byte buf[3];
994
995 png_crc_read(png_ptr, buf, 3);
996 /* Don't depend upon png_color being any order */
997 palette[i].red = buf[0];
998 palette[i].green = buf[1];
999 palette[i].blue = buf[2];
1000 }
1001 #endif
1002
1003 /* If we actually need the PLTE chunk (ie for a paletted image), we do
1004 * whatever the normal CRC configuration tells us. However, if we
1005 * have an RGB image, the PLTE can be considered ancillary, so
1006 * we will act as though it is.
1007 */
1008 #ifndef PNG_READ_OPT_PLTE_SUPPORTED
1009 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1010 #endif
1011 {
1012 png_crc_finish(png_ptr, (int) length - num * 3);
1013 }
1014
1015 #ifndef PNG_READ_OPT_PLTE_SUPPORTED
1016 else if (png_crc_error(png_ptr) != 0) /* Only if we have a CRC error */
1017 {
1018 /* If we don't want to use the data from an ancillary chunk,
1019 * we have two options: an error abort, or a warning and we
1020 * ignore the data in this chunk (which should be OK, since
1021 * it's considered ancillary for a RGB or RGBA image).
1022 *
1023 * IMPLEMENTATION NOTE: this is only here because png_crc_finish uses the
1024 * chunk type to determine whether to check the ancillary or the critical
1025 * flags.
1026 */
1027 if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_USE) == 0)
1028 {
1029 if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) != 0)
1030 return;
1031
1032 else
1033 png_chunk_error(png_ptr, "CRC error");
1034 }
1035
1036 /* Otherwise, we (optionally) emit a warning and use the chunk. */
1037 else if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) == 0)
1038 png_chunk_warning(png_ptr, "CRC error");
1039 }
1040 #endif
1041
1042 /* TODO: png_set_PLTE has the side effect of setting png_ptr->palette to its
1043 * own copy of the palette. This has the side effect that when png_start_row
1044 * is called (this happens after any call to png_read_update_info) the
1045 * info_ptr palette gets changed. This is extremely unexpected and
1046 * confusing.
1047 *
1048 * Fix this by not sharing the palette in this way.
1049 */
1050 png_set_PLTE(png_ptr, info_ptr, palette, num);
1051
1052 /* The three chunks, bKGD, hIST and tRNS *must* appear after PLTE and before
1053 * IDAT. Prior to 1.6.0 this was not checked; instead the code merely
1054 * checked the apparent validity of a tRNS chunk inserted before PLTE on a
1055 * palette PNG. 1.6.0 attempts to rigorously follow the standard and
1056 * therefore does a benign error if the erroneous condition is detected *and*
1057 * cancels the tRNS if the benign error returns. The alternative is to
1058 * amend the standard since it would be rather hypocritical of the standards
1059 * maintainers to ignore it.
1060 */
1061 #ifdef PNG_READ_tRNS_SUPPORTED
1062 if (png_ptr->num_trans > 0 ||
1063 (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS) != 0))
1064 {
1065 /* Cancel this because otherwise it would be used if the transforms
1066 * require it. Don't cancel the 'valid' flag because this would prevent
1067 * detection of duplicate chunks.
1068 */
1069 png_ptr->num_trans = 0;
1070
1071 if (info_ptr != NULL)
1072 info_ptr->num_trans = 0;
1073
1074 png_chunk_benign_error(png_ptr, "tRNS must be after");
1075 }
1076 #endif
1077
1078 #ifdef PNG_READ_hIST_SUPPORTED
1079 if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST) != 0)
1080 png_chunk_benign_error(png_ptr, "hIST must be after");
1081 #endif
1082
1083 #ifdef PNG_READ_bKGD_SUPPORTED
1084 if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD) != 0)
1085 png_chunk_benign_error(png_ptr, "bKGD must be after");
1086 #endif
1087 }
1088
1089 void /* PRIVATE */
1090 png_handle_IEND(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1091 {
1092 png_debug(1, "in png_handle_IEND");
1093
1094 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0 ||
1095 (png_ptr->mode & PNG_HAVE_IDAT) == 0)
1096 png_chunk_error(png_ptr, "out of place");
1097
1098 png_ptr->mode |= (PNG_AFTER_IDAT | PNG_HAVE_IEND);
1099
1100 png_crc_finish(png_ptr, length);
1101
1102 if (length != 0)
1103 png_chunk_benign_error(png_ptr, "invalid");
1104
1105 PNG_UNUSED(info_ptr)
1106 }
1107
1108 #ifdef PNG_READ_gAMA_SUPPORTED
1109 void /* PRIVATE */
1110 png_handle_gAMA(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1111 {
1112 png_fixed_point igamma;
1113 png_byte buf[4];
1114
1115 png_debug(1, "in png_handle_gAMA");
1116
1117 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1118 png_chunk_error(png_ptr, "missing IHDR");
1119
1120 else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
1121 {
1122 png_crc_finish(png_ptr, length);
1123 png_chunk_benign_error(png_ptr, "out of place");
1124 return;
1125 }
1126
1127 if (length != 4)
1128 {
1129 png_crc_finish(png_ptr, length);
1130 png_chunk_benign_error(png_ptr, "invalid");
1131 return;
1132 }
1133
1134 png_crc_read(png_ptr, buf, 4);
1135
1136 if (png_crc_finish(png_ptr, 0) != 0)
1137 return;
1138
1139 igamma = png_get_fixed_point(NULL, buf);
1140
1141 png_colorspace_set_gamma(png_ptr, &png_ptr->colorspace, igamma);
1142 png_colorspace_sync(png_ptr, info_ptr);
1143 }
1144 #endif
1145
1146 #ifdef PNG_READ_sBIT_SUPPORTED
1147 void /* PRIVATE */
1148 png_handle_sBIT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1149 {
1150 unsigned int truelen, i;
1151 png_byte sample_depth;
1152 png_byte buf[4];
1153
1154 png_debug(1, "in png_handle_sBIT");
1155
1156 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1157 png_chunk_error(png_ptr, "missing IHDR");
1158
1159 else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
1160 {
1161 png_crc_finish(png_ptr, length);
1162 png_chunk_benign_error(png_ptr, "out of place");
1163 return;
1164 }
1165
1166 if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sBIT) != 0)
1167 {
1168 png_crc_finish(png_ptr, length);
1169 png_chunk_benign_error(png_ptr, "duplicate");
1170 return;
1171 }
1172
1173 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1174 {
1175 truelen = 3;
1176 sample_depth = 8;
1177 }
1178
1179 else
1180 {
1181 truelen = png_ptr->channels;
1182 sample_depth = png_ptr->bit_depth;
1183 }
1184
1185 if (length != truelen || length > 4)
1186 {
1187 png_chunk_benign_error(png_ptr, "invalid");
1188 png_crc_finish(png_ptr, length);
1189 return;
1190 }
1191
1192 buf[0] = buf[1] = buf[2] = buf[3] = sample_depth;
1193 png_crc_read(png_ptr, buf, truelen);
1194
1195 if (png_crc_finish(png_ptr, 0) != 0)
1196 return;
1197
1198 for (i=0; i<truelen; ++i)
1199 {
1200 if (buf[i] == 0 || buf[i] > sample_depth)
1201 {
1202 png_chunk_benign_error(png_ptr, "invalid");
1203 return;
1204 }
1205 }
1206
1207 if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
1208 {
1209 png_ptr->sig_bit.red = buf[0];
1210 png_ptr->sig_bit.green = buf[1];
1211 png_ptr->sig_bit.blue = buf[2];
1212 png_ptr->sig_bit.alpha = buf[3];
1213 }
1214
1215 else
1216 {
1217 png_ptr->sig_bit.gray = buf[0];
1218 png_ptr->sig_bit.red = buf[0];
1219 png_ptr->sig_bit.green = buf[0];
1220 png_ptr->sig_bit.blue = buf[0];
1221 png_ptr->sig_bit.alpha = buf[1];
1222 }
1223
1224 png_set_sBIT(png_ptr, info_ptr, &(png_ptr->sig_bit));
1225 }
1226 #endif
1227
1228 #ifdef PNG_READ_cHRM_SUPPORTED
1229 void /* PRIVATE */
1230 png_handle_cHRM(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1231 {
1232 png_byte buf[32];
1233 png_xy xy;
1234
1235 png_debug(1, "in png_handle_cHRM");
1236
1237 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1238 png_chunk_error(png_ptr, "missing IHDR");
1239
1240 else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
1241 {
1242 png_crc_finish(png_ptr, length);
1243 png_chunk_benign_error(png_ptr, "out of place");
1244 return;
1245 }
1246
1247 if (length != 32)
1248 {
1249 png_crc_finish(png_ptr, length);
1250 png_chunk_benign_error(png_ptr, "invalid");
1251 return;
1252 }
1253
1254 png_crc_read(png_ptr, buf, 32);
1255
1256 if (png_crc_finish(png_ptr, 0) != 0)
1257 return;
1258
1259 xy.whitex = png_get_fixed_point(NULL, buf);
1260 xy.whitey = png_get_fixed_point(NULL, buf + 4);
1261 xy.redx = png_get_fixed_point(NULL, buf + 8);
1262 xy.redy = png_get_fixed_point(NULL, buf + 12);
1263 xy.greenx = png_get_fixed_point(NULL, buf + 16);
1264 xy.greeny = png_get_fixed_point(NULL, buf + 20);
1265 xy.bluex = png_get_fixed_point(NULL, buf + 24);
1266 xy.bluey = png_get_fixed_point(NULL, buf + 28);
1267
1268 if (xy.whitex == PNG_FIXED_ERROR ||
1269 xy.whitey == PNG_FIXED_ERROR ||
1270 xy.redx == PNG_FIXED_ERROR ||
1271 xy.redy == PNG_FIXED_ERROR ||
1272 xy.greenx == PNG_FIXED_ERROR ||
1273 xy.greeny == PNG_FIXED_ERROR ||
1274 xy.bluex == PNG_FIXED_ERROR ||
1275 xy.bluey == PNG_FIXED_ERROR)
1276 {
1277 png_chunk_benign_error(png_ptr, "invalid values");
1278 return;
1279 }
1280
1281 /* If a colorspace error has already been output skip this chunk */
1282 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0)
1283 return;
1284
1285 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_FROM_cHRM) != 0)
1286 {
1287 png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID;
1288 png_colorspace_sync(png_ptr, info_ptr);
1289 png_chunk_benign_error(png_ptr, "duplicate");
1290 return;
1291 }
1292
1293 png_ptr->colorspace.flags |= PNG_COLORSPACE_FROM_cHRM;
1294 (void)png_colorspace_set_chromaticities(png_ptr, &png_ptr->colorspace, &xy,
1295 1/*prefer cHRM values*/);
1296 png_colorspace_sync(png_ptr, info_ptr);
1297 }
1298 #endif
1299
1300 #ifdef PNG_READ_sRGB_SUPPORTED
1301 void /* PRIVATE */
1302 png_handle_sRGB(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1303 {
1304 png_byte intent;
1305
1306 png_debug(1, "in png_handle_sRGB");
1307
1308 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1309 png_chunk_error(png_ptr, "missing IHDR");
1310
1311 else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
1312 {
1313 png_crc_finish(png_ptr, length);
1314 png_chunk_benign_error(png_ptr, "out of place");
1315 return;
1316 }
1317
1318 if (length != 1)
1319 {
1320 png_crc_finish(png_ptr, length);
1321 png_chunk_benign_error(png_ptr, "invalid");
1322 return;
1323 }
1324
1325 png_crc_read(png_ptr, &intent, 1);
1326
1327 if (png_crc_finish(png_ptr, 0) != 0)
1328 return;
1329
1330 /* If a colorspace error has already been output skip this chunk */
1331 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0)
1332 return;
1333
1334 /* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect
1335 * this.
1336 */
1337 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_INTENT) != 0)
1338 {
1339 png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID;
1340 png_colorspace_sync(png_ptr, info_ptr);
1341 png_chunk_benign_error(png_ptr, "too many profiles");
1342 return;
1343 }
1344
1345 (void)png_colorspace_set_sRGB(png_ptr, &png_ptr->colorspace, intent);
1346 png_colorspace_sync(png_ptr, info_ptr);
1347 }
1348 #endif /* READ_sRGB */
1349
1350 #ifdef PNG_READ_iCCP_SUPPORTED
1351 void /* PRIVATE */
1352 png_handle_iCCP(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1353 /* Note: this does not properly handle profiles that are > 64K under DOS */
1354 {
1355 png_const_charp errmsg = NULL; /* error message output, or no error */
1356 int finished = 0; /* crc checked */
1357
1358 png_debug(1, "in png_handle_iCCP");
1359
1360 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1361 png_chunk_error(png_ptr, "missing IHDR");
1362
1363 else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
1364 {
1365 png_crc_finish(png_ptr, length);
1366 png_chunk_benign_error(png_ptr, "out of place");
1367 return;
1368 }
1369
1370 /* Consistent with all the above colorspace handling an obviously *invalid*
1371 * chunk is just ignored, so does not invalidate the color space. An
1372 * alternative is to set the 'invalid' flags at the start of this routine
1373 * and only clear them in they were not set before and all the tests pass.
1374 * The minimum 'deflate' stream is assumed to be just the 2 byte header and
1375 * 4 byte checksum. The keyword must be at least one character and there is
1376 * a terminator (0) byte and the compression method.
1377 */
1378 if (length < 9)
1379 {
1380 png_crc_finish(png_ptr, length);
1381 png_chunk_benign_error(png_ptr, "too short");
1382 return;
1383 }
1384
1385 /* If a colorspace error has already been output skip this chunk */
1386 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0)
1387 {
1388 png_crc_finish(png_ptr, length);
1389 return;
1390 }
1391
1392 /* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect
1393 * this.
1394 */
1395 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_INTENT) == 0)
1396 {
1397 uInt read_length, keyword_length;
1398 char keyword[81];
1399
1400 /* Find the keyword; the keyword plus separator and compression method
1401 * bytes can be at most 81 characters long.
1402 */
1403 read_length = 81; /* maximum */
1404 if (read_length > length)
1405 read_length = (uInt)length;
1406
1407 png_crc_read(png_ptr, (png_bytep)keyword, read_length);
1408 length -= read_length;
1409
1410 keyword_length = 0;
1411 while (keyword_length < 80 && keyword_length < read_length &&
1412 keyword[keyword_length] != 0)
1413 ++keyword_length;
1414
1415 /* TODO: make the keyword checking common */
1416 if (keyword_length >= 1 && keyword_length <= 79)
1417 {
1418 /* We only understand '0' compression - deflate - so if we get a
1419 * different value we can't safely decode the chunk.
1420 */
1421 if (keyword_length+1 < read_length &&
1422 keyword[keyword_length+1] == PNG_COMPRESSION_TYPE_BASE)
1423 {
1424 read_length -= keyword_length+2;
1425
1426 if (png_inflate_claim(png_ptr, png_iCCP) == Z_OK)
1427 {
1428 Byte profile_header[132];
1429 Byte local_buffer[PNG_INFLATE_BUF_SIZE];
1430 png_alloc_size_t size = (sizeof profile_header);
1431
1432 png_ptr->zstream.next_in = (Bytef*)keyword + (keyword_length+2);
1433 png_ptr->zstream.avail_in = read_length;
1434 (void)png_inflate_read(png_ptr, local_buffer,
1435 (sizeof local_buffer), &length, profile_header, &size,
1436 0/*finish: don't, because the output is too small*/);
1437
1438 if (size == 0)
1439 {
1440 /* We have the ICC profile header; do the basic header checks.
1441 */
1442 const png_uint_32 profile_length =
1443 png_get_uint_32(profile_header);
1444
1445 if (png_icc_check_length(png_ptr, &png_ptr->colorspace,
1446 keyword, profile_length) != 0)
1447 {
1448 /* The length is apparently ok, so we can check the 132
1449 * byte header.
1450 */
1451 if (png_icc_check_header(png_ptr, &png_ptr->colorspace,
1452 keyword, profile_length, profile_header,
1453 png_ptr->color_type) != 0)
1454 {
1455 /* Now read the tag table; a variable size buffer is
1456 * needed at this point, allocate one for the whole
1457 * profile. The header check has already validated
1458 * that none of these stuff will overflow.
1459 */
1460 const png_uint_32 tag_count = png_get_uint_32(
1461 profile_header+128);
1462 png_bytep profile = png_read_buffer(png_ptr,
1463 profile_length, 2/*silent*/);
1464
1465 if (profile != NULL)
1466 {
1467 memcpy(profile, profile_header,
1468 (sizeof profile_header));
1469
1470 size = 12 * tag_count;
1471
1472 (void)png_inflate_read(png_ptr, local_buffer,
1473 (sizeof local_buffer), &length,
1474 profile + (sizeof profile_header), &size, 0);
1475
1476 /* Still expect a buffer error because we expect
1477 * there to be some tag data!
1478 */
1479 if (size == 0)
1480 {
1481 if (png_icc_check_tag_table(png_ptr,
1482 &png_ptr->colorspace, keyword, profile_length,
1483 profile) != 0)
1484 {
1485 /* The profile has been validated for basic
1486 * security issues, so read the whole thing in.
1487 */
1488 size = profile_length - (sizeof profile_header)
1489 - 12 * tag_count;
1490
1491 (void)png_inflate_read(png_ptr, local_buffer,
1492 (sizeof local_buffer), &length,
1493 profile + (sizeof profile_header) +
1494 12 * tag_count, &size, 1/*finish*/);
1495
1496 if (length > 0 && !(png_ptr->flags &
1497 PNG_FLAG_BENIGN_ERRORS_WARN))
1498 errmsg = "extra compressed data";
1499
1500 /* But otherwise allow extra data: */
1501 else if (size == 0)
1502 {
1503 if (length > 0)
1504 {
1505 /* This can be handled completely, so
1506 * keep going.
1507 */
1508 png_chunk_warning(png_ptr,
1509 "extra compressed data");
1510 }
1511
1512 png_crc_finish(png_ptr, length);
1513 finished = 1;
1514
1515 # ifdef PNG_sRGB_SUPPORTED
1516 /* Check for a match against sRGB */
1517 png_icc_set_sRGB(png_ptr,
1518 &png_ptr->colorspace, profile,
1519 png_ptr->zstream.adler);
1520 # endif
1521
1522 /* Steal the profile for info_ptr. */
1523 if (info_ptr != NULL)
1524 {
1525 png_free_data(png_ptr, info_ptr,
1526 PNG_FREE_ICCP, 0);
1527
1528 info_ptr->iccp_name = png_voidcast(char*,
1529 png_malloc_base(png_ptr,
1530 keyword_length+1));
1531 if (info_ptr->iccp_name != NULL)
1532 {
1533 memcpy(info_ptr->iccp_name, keyword,
1534 keyword_length+1);
1535 info_ptr->iccp_proflen =
1536 profile_length;
1537 info_ptr->iccp_profile = profile;
1538 png_ptr->read_buffer = NULL; /*steal*/
1539 info_ptr->free_me |= PNG_FREE_ICCP;
1540 info_ptr->valid |= PNG_INFO_iCCP;
1541 }
1542
1543 else
1544 {
1545 png_ptr->colorspace.flags |=
1546 PNG_COLORSPACE_INVALID;
1547 errmsg = "out of memory";
1548 }
1549 }
1550
1551 /* else the profile remains in the read
1552 * buffer which gets reused for subsequent
1553 * chunks.
1554 */
1555
1556 if (info_ptr != NULL)
1557 png_colorspace_sync(png_ptr, info_ptr);
1558
1559 if (errmsg == NULL)
1560 {
1561 png_ptr->zowner = 0;
1562 return;
1563 }
1564 }
1565
1566 else if (size > 0)
1567 errmsg = "truncated";
1568
1569 #ifndef __COVERITY__
1570 else
1571 errmsg = png_ptr->zstream.msg;
1572 #endif
1573 }
1574
1575 /* else png_icc_check_tag_table output an error */
1576 }
1577
1578 else /* profile truncated */
1579 errmsg = png_ptr->zstream.msg;
1580 }
1581
1582 else
1583 errmsg = "out of memory";
1584 }
1585
1586 /* else png_icc_check_header output an error */
1587 }
1588
1589 /* else png_icc_check_length output an error */
1590 }
1591
1592 else /* profile truncated */
1593 errmsg = png_ptr->zstream.msg;
1594
1595 /* Release the stream */
1596 png_ptr->zowner = 0;
1597 }
1598
1599 else /* png_inflate_claim failed */
1600 errmsg = png_ptr->zstream.msg;
1601 }
1602
1603 else
1604 errmsg = "bad compression method"; /* or missing */
1605 }
1606
1607 else
1608 errmsg = "bad keyword";
1609 }
1610
1611 else
1612 errmsg = "too many profiles";
1613
1614 /* Failure: the reason is in 'errmsg' */
1615 if (finished == 0)
1616 png_crc_finish(png_ptr, length);
1617
1618 png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID;
1619 png_colorspace_sync(png_ptr, info_ptr);
1620 if (errmsg != NULL) /* else already output */
1621 png_chunk_benign_error(png_ptr, errmsg);
1622 }
1623 #endif /* READ_iCCP */
1624
1625 #ifdef PNG_READ_sPLT_SUPPORTED
1626 void /* PRIVATE */
1627 png_handle_sPLT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1628 /* Note: this does not properly handle chunks that are > 64K under DOS */
1629 {
1630 png_bytep entry_start, buffer;
1631 png_sPLT_t new_palette;
1632 png_sPLT_entryp pp;
1633 png_uint_32 data_length;
1634 int entry_size, i;
1635 png_uint_32 skip = 0;
1636 png_uint_32 dl;
1637 png_size_t max_dl;
1638
1639 png_debug(1, "in png_handle_sPLT");
1640
1641 #ifdef PNG_USER_LIMITS_SUPPORTED
1642 if (png_ptr->user_chunk_cache_max != 0)
1643 {
1644 if (png_ptr->user_chunk_cache_max == 1)
1645 {
1646 png_crc_finish(png_ptr, length);
1647 return;
1648 }
1649
1650 if (--png_ptr->user_chunk_cache_max == 1)
1651 {
1652 png_warning(png_ptr, "No space in chunk cache for sPLT");
1653 png_crc_finish(png_ptr, length);
1654 return;
1655 }
1656 }
1657 #endif
1658
1659 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1660 png_chunk_error(png_ptr, "missing IHDR");
1661
1662 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
1663 {
1664 png_crc_finish(png_ptr, length);
1665 png_chunk_benign_error(png_ptr, "out of place");
1666 return;
1667 }
1668
1669 #ifdef PNG_MAX_MALLOC_64K
1670 if (length > 65535U)
1671 {
1672 png_crc_finish(png_ptr, length);
1673 png_chunk_benign_error(png_ptr, "too large to fit in memory");
1674 return;
1675 }
1676 #endif
1677
1678 buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/);
1679 if (buffer == NULL)
1680 {
1681 png_crc_finish(png_ptr, length);
1682 png_chunk_benign_error(png_ptr, "out of memory");
1683 return;
1684 }
1685
1686
1687 /* WARNING: this may break if size_t is less than 32 bits; it is assumed
1688 * that the PNG_MAX_MALLOC_64K test is enabled in this case, but this is a
1689 * potential breakage point if the types in pngconf.h aren't exactly right.
1690 */
1691 png_crc_read(png_ptr, buffer, length);
1692
1693 if (png_crc_finish(png_ptr, skip) != 0)
1694 return;
1695
1696 buffer[length] = 0;
1697
1698 for (entry_start = buffer; *entry_start; entry_start++)
1699 /* Empty loop to find end of name */ ;
1700
1701 ++entry_start;
1702
1703 /* A sample depth should follow the separator, and we should be on it */
1704 if (length < 2U || entry_start > buffer + (length - 2U))
1705 {
1706 png_warning(png_ptr, "malformed sPLT chunk");
1707 return;
1708 }
1709
1710 new_palette.depth = *entry_start++;
1711 entry_size = (new_palette.depth == 8 ? 6 : 10);
1712 /* This must fit in a png_uint_32 because it is derived from the original
1713 * chunk data length.
1714 */
1715 data_length = length - (png_uint_32)(entry_start - buffer);
1716
1717 /* Integrity-check the data length */
1718 if ((data_length % entry_size) != 0)
1719 {
1720 png_warning(png_ptr, "sPLT chunk has bad length");
1721 return;
1722 }
1723
1724 dl = (png_int_32)(data_length / entry_size);
1725 max_dl = PNG_SIZE_MAX / (sizeof (png_sPLT_entry));
1726
1727 if (dl > max_dl)
1728 {
1729 png_warning(png_ptr, "sPLT chunk too long");
1730 return;
1731 }
1732
1733 new_palette.nentries = (png_int_32)(data_length / entry_size);
1734
1735 new_palette.entries = (png_sPLT_entryp)png_malloc_warn(
1736 png_ptr, new_palette.nentries * (sizeof (png_sPLT_entry)));
1737
1738 if (new_palette.entries == NULL)
1739 {
1740 png_warning(png_ptr, "sPLT chunk requires too much memory");
1741 return;
1742 }
1743
1744 #ifdef PNG_POINTER_INDEXING_SUPPORTED
1745 for (i = 0; i < new_palette.nentries; i++)
1746 {
1747 pp = new_palette.entries + i;
1748
1749 if (new_palette.depth == 8)
1750 {
1751 pp->red = *entry_start++;
1752 pp->green = *entry_start++;
1753 pp->blue = *entry_start++;
1754 pp->alpha = *entry_start++;
1755 }
1756
1757 else
1758 {
1759 pp->red = png_get_uint_16(entry_start); entry_start += 2;
1760 pp->green = png_get_uint_16(entry_start); entry_start += 2;
1761 pp->blue = png_get_uint_16(entry_start); entry_start += 2;
1762 pp->alpha = png_get_uint_16(entry_start); entry_start += 2;
1763 }
1764
1765 pp->frequency = png_get_uint_16(entry_start); entry_start += 2;
1766 }
1767 #else
1768 pp = new_palette.entries;
1769
1770 for (i = 0; i < new_palette.nentries; i++)
1771 {
1772
1773 if (new_palette.depth == 8)
1774 {
1775 pp[i].red = *entry_start++;
1776 pp[i].green = *entry_start++;
1777 pp[i].blue = *entry_start++;
1778 pp[i].alpha = *entry_start++;
1779 }
1780
1781 else
1782 {
1783 pp[i].red = png_get_uint_16(entry_start); entry_start += 2;
1784 pp[i].green = png_get_uint_16(entry_start); entry_start += 2;
1785 pp[i].blue = png_get_uint_16(entry_start); entry_start += 2;
1786 pp[i].alpha = png_get_uint_16(entry_start); entry_start += 2;
1787 }
1788
1789 pp[i].frequency = png_get_uint_16(entry_start); entry_start += 2;
1790 }
1791 #endif
1792
1793 /* Discard all chunk data except the name and stash that */
1794 new_palette.name = (png_charp)buffer;
1795
1796 png_set_sPLT(png_ptr, info_ptr, &new_palette, 1);
1797
1798 png_free(png_ptr, new_palette.entries);
1799 }
1800 #endif /* READ_sPLT */
1801
1802 #ifdef PNG_READ_tRNS_SUPPORTED
1803 void /* PRIVATE */
1804 png_handle_tRNS(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1805 {
1806 png_byte readbuf[PNG_MAX_PALETTE_LENGTH];
1807
1808 png_debug(1, "in png_handle_tRNS");
1809
1810 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1811 png_chunk_error(png_ptr, "missing IHDR");
1812
1813 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
1814 {
1815 png_crc_finish(png_ptr, length);
1816 png_chunk_benign_error(png_ptr, "out of place");
1817 return;
1818 }
1819
1820 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS) != 0)
1821 {
1822 png_crc_finish(png_ptr, length);
1823 png_chunk_benign_error(png_ptr, "duplicate");
1824 return;
1825 }
1826
1827 if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
1828 {
1829 png_byte buf[2];
1830
1831 if (length != 2)
1832 {
1833 png_crc_finish(png_ptr, length);
1834 png_chunk_benign_error(png_ptr, "invalid");
1835 return;
1836 }
1837
1838 png_crc_read(png_ptr, buf, 2);
1839 png_ptr->num_trans = 1;
1840 png_ptr->trans_color.gray = png_get_uint_16(buf);
1841 }
1842
1843 else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
1844 {
1845 png_byte buf[6];
1846
1847 if (length != 6)
1848 {
1849 png_crc_finish(png_ptr, length);
1850 png_chunk_benign_error(png_ptr, "invalid");
1851 return;
1852 }
1853
1854 png_crc_read(png_ptr, buf, length);
1855 png_ptr->num_trans = 1;
1856 png_ptr->trans_color.red = png_get_uint_16(buf);
1857 png_ptr->trans_color.green = png_get_uint_16(buf + 2);
1858 png_ptr->trans_color.blue = png_get_uint_16(buf + 4);
1859 }
1860
1861 else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1862 {
1863 if ((png_ptr->mode & PNG_HAVE_PLTE) == 0)
1864 {
1865 /* TODO: is this actually an error in the ISO spec? */
1866 png_crc_finish(png_ptr, length);
1867 png_chunk_benign_error(png_ptr, "out of place");
1868 return;
1869 }
1870
1871 if (length > (unsigned int) png_ptr->num_palette ||
1872 length > (unsigned int) PNG_MAX_PALETTE_LENGTH ||
1873 length == 0)
1874 {
1875 png_crc_finish(png_ptr, length);
1876 png_chunk_benign_error(png_ptr, "invalid");
1877 return;
1878 }
1879
1880 png_crc_read(png_ptr, readbuf, length);
1881 png_ptr->num_trans = (png_uint_16)length;
1882 }
1883
1884 else
1885 {
1886 png_crc_finish(png_ptr, length);
1887 png_chunk_benign_error(png_ptr, "invalid with alpha channel");
1888 return;
1889 }
1890
1891 if (png_crc_finish(png_ptr, 0) != 0)
1892 {
1893 png_ptr->num_trans = 0;
1894 return;
1895 }
1896
1897 /* TODO: this is a horrible side effect in the palette case because the
1898 * png_struct ends up with a pointer to the tRNS buffer owned by the
1899 * png_info. Fix this.
1900 */
1901 png_set_tRNS(png_ptr, info_ptr, readbuf, png_ptr->num_trans,
1902 &(png_ptr->trans_color));
1903 }
1904 #endif
1905
1906 #ifdef PNG_READ_bKGD_SUPPORTED
1907 void /* PRIVATE */
1908 png_handle_bKGD(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1909 {
1910 unsigned int truelen;
1911 png_byte buf[6];
1912 png_color_16 background;
1913
1914 png_debug(1, "in png_handle_bKGD");
1915
1916 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1917 png_chunk_error(png_ptr, "missing IHDR");
1918
1919 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0 ||
1920 (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
1921 (png_ptr->mode & PNG_HAVE_PLTE) == 0))
1922 {
1923 png_crc_finish(png_ptr, length);
1924 png_chunk_benign_error(png_ptr, "out of place");
1925 return;
1926 }
1927
1928 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD) != 0)
1929 {
1930 png_crc_finish(png_ptr, length);
1931 png_chunk_benign_error(png_ptr, "duplicate");
1932 return;
1933 }
1934
1935 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1936 truelen = 1;
1937
1938 else if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
1939 truelen = 6;
1940
1941 else
1942 truelen = 2;
1943
1944 if (length != truelen)
1945 {
1946 png_crc_finish(png_ptr, length);
1947 png_chunk_benign_error(png_ptr, "invalid");
1948 return;
1949 }
1950
1951 png_crc_read(png_ptr, buf, truelen);
1952
1953 if (png_crc_finish(png_ptr, 0) != 0)
1954 return;
1955
1956 /* We convert the index value into RGB components so that we can allow
1957 * arbitrary RGB values for background when we have transparency, and
1958 * so it is easy to determine the RGB values of the background color
1959 * from the info_ptr struct.
1960 */
1961 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1962 {
1963 background.index = buf[0];
1964
1965 if (info_ptr != NULL && info_ptr->num_palette != 0)
1966 {
1967 if (buf[0] >= info_ptr->num_palette)
1968 {
1969 png_chunk_benign_error(png_ptr, "invalid index");
1970 return;
1971 }
1972
1973 background.red = (png_uint_16)png_ptr->palette[buf[0]].red;
1974 background.green = (png_uint_16)png_ptr->palette[buf[0]].green;
1975 background.blue = (png_uint_16)png_ptr->palette[buf[0]].blue;
1976 }
1977
1978 else
1979 background.red = background.green = background.blue = 0;
1980
1981 background.gray = 0;
1982 }
1983
1984 else if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0) /* GRAY */
1985 {
1986 background.index = 0;
1987 background.red =
1988 background.green =
1989 background.blue =
1990 background.gray = png_get_uint_16(buf);
1991 }
1992
1993 else
1994 {
1995 background.index = 0;
1996 background.red = png_get_uint_16(buf);
1997 background.green = png_get_uint_16(buf + 2);
1998 background.blue = png_get_uint_16(buf + 4);
1999 background.gray = 0;
2000 }
2001
2002 png_set_bKGD(png_ptr, info_ptr, &background);
2003 }
2004 #endif
2005
2006 #ifdef PNG_READ_hIST_SUPPORTED
2007 void /* PRIVATE */
2008 png_handle_hIST(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2009 {
2010 unsigned int num, i;
2011 png_uint_16 readbuf[PNG_MAX_PALETTE_LENGTH];
2012
2013 png_debug(1, "in png_handle_hIST");
2014
2015 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2016 png_chunk_error(png_ptr, "missing IHDR");
2017
2018 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0 ||
2019 (png_ptr->mode & PNG_HAVE_PLTE) == 0)
2020 {
2021 png_crc_finish(png_ptr, length);
2022 png_chunk_benign_error(png_ptr, "out of place");
2023 return;
2024 }
2025
2026 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST) != 0)
2027 {
2028 png_crc_finish(png_ptr, length);
2029 png_chunk_benign_error(png_ptr, "duplicate");
2030 return;
2031 }
2032
2033 num = length / 2 ;
2034
2035 if (num != (unsigned int) png_ptr->num_palette ||
2036 num > (unsigned int) PNG_MAX_PALETTE_LENGTH)
2037 {
2038 png_crc_finish(png_ptr, length);
2039 png_chunk_benign_error(png_ptr, "invalid");
2040 return;
2041 }
2042
2043 for (i = 0; i < num; i++)
2044 {
2045 png_byte buf[2];
2046
2047 png_crc_read(png_ptr, buf, 2);
2048 readbuf[i] = png_get_uint_16(buf);
2049 }
2050
2051 if (png_crc_finish(png_ptr, 0) != 0)
2052 return;
2053
2054 png_set_hIST(png_ptr, info_ptr, readbuf);
2055 }
2056 #endif
2057
2058 #ifdef PNG_READ_pHYs_SUPPORTED
2059 void /* PRIVATE */
2060 png_handle_pHYs(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2061 {
2062 png_byte buf[9];
2063 png_uint_32 res_x, res_y;
2064 int unit_type;
2065
2066 png_debug(1, "in png_handle_pHYs");
2067
2068 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2069 png_chunk_error(png_ptr, "missing IHDR");
2070
2071 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2072 {
2073 png_crc_finish(png_ptr, length);
2074 png_chunk_benign_error(png_ptr, "out of place");
2075 return;
2076 }
2077
2078 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs) != 0)
2079 {
2080 png_crc_finish(png_ptr, length);
2081 png_chunk_benign_error(png_ptr, "duplicate");
2082 return;
2083 }
2084
2085 if (length != 9)
2086 {
2087 png_crc_finish(png_ptr, length);
2088 png_chunk_benign_error(png_ptr, "invalid");
2089 return;
2090 }
2091
2092 png_crc_read(png_ptr, buf, 9);
2093
2094 if (png_crc_finish(png_ptr, 0) != 0)
2095 return;
2096
2097 res_x = png_get_uint_32(buf);
2098 res_y = png_get_uint_32(buf + 4);
2099 unit_type = buf[8];
2100 png_set_pHYs(png_ptr, info_ptr, res_x, res_y, unit_type);
2101 }
2102 #endif
2103
2104 #ifdef PNG_READ_oFFs_SUPPORTED
2105 void /* PRIVATE */
2106 png_handle_oFFs(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2107 {
2108 png_byte buf[9];
2109 png_int_32 offset_x, offset_y;
2110 int unit_type;
2111
2112 png_debug(1, "in png_handle_oFFs");
2113
2114 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2115 png_chunk_error(png_ptr, "missing IHDR");
2116
2117 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2118 {
2119 png_crc_finish(png_ptr, length);
2120 png_chunk_benign_error(png_ptr, "out of place");
2121 return;
2122 }
2123
2124 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs) != 0)
2125 {
2126 png_crc_finish(png_ptr, length);
2127 png_chunk_benign_error(png_ptr, "duplicate");
2128 return;
2129 }
2130
2131 if (length != 9)
2132 {
2133 png_crc_finish(png_ptr, length);
2134 png_chunk_benign_error(png_ptr, "invalid");
2135 return;
2136 }
2137
2138 png_crc_read(png_ptr, buf, 9);
2139
2140 if (png_crc_finish(png_ptr, 0) != 0)
2141 return;
2142
2143 offset_x = png_get_int_32(buf);
2144 offset_y = png_get_int_32(buf + 4);
2145 unit_type = buf[8];
2146 png_set_oFFs(png_ptr, info_ptr, offset_x, offset_y, unit_type);
2147 }
2148 #endif
2149
2150 #ifdef PNG_READ_pCAL_SUPPORTED
2151 /* Read the pCAL chunk (described in the PNG Extensions document) */
2152 void /* PRIVATE */
2153 png_handle_pCAL(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2154 {
2155 png_int_32 X0, X1;
2156 png_byte type, nparams;
2157 png_bytep buffer, buf, units, endptr;
2158 png_charpp params;
2159 int i;
2160
2161 png_debug(1, "in png_handle_pCAL");
2162
2163 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2164 png_chunk_error(png_ptr, "missing IHDR");
2165
2166 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2167 {
2168 png_crc_finish(png_ptr, length);
2169 png_chunk_benign_error(png_ptr, "out of place");
2170 return;
2171 }
2172
2173 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pCAL) != 0)
2174 {
2175 png_crc_finish(png_ptr, length);
2176 png_chunk_benign_error(png_ptr, "duplicate");
2177 return;
2178 }
2179
2180 png_debug1(2, "Allocating and reading pCAL chunk data (%u bytes)",
2181 length + 1);
2182
2183 buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/);
2184
2185 if (buffer == NULL)
2186 {
2187 png_crc_finish(png_ptr, length);
2188 png_chunk_benign_error(png_ptr, "out of memory");
2189 return;
2190 }
2191
2192 png_crc_read(png_ptr, buffer, length);
2193
2194 if (png_crc_finish(png_ptr, 0) != 0)
2195 return;
2196
2197 buffer[length] = 0; /* Null terminate the last string */
2198
2199 png_debug(3, "Finding end of pCAL purpose string");
2200 for (buf = buffer; *buf; buf++)
2201 /* Empty loop */ ;
2202
2203 endptr = buffer + length;
2204
2205 /* We need to have at least 12 bytes after the purpose string
2206 * in order to get the parameter information.
2207 */
2208 if (endptr - buf <= 12)
2209 {
2210 png_chunk_benign_error(png_ptr, "invalid");
2211 return;
2212 }
2213
2214 png_debug(3, "Reading pCAL X0, X1, type, nparams, and units");
2215 X0 = png_get_int_32((png_bytep)buf+1);
2216 X1 = png_get_int_32((png_bytep)buf+5);
2217 type = buf[9];
2218 nparams = buf[10];
2219 units = buf + 11;
2220
2221 png_debug(3, "Checking pCAL equation type and number of parameters");
2222 /* Check that we have the right number of parameters for known
2223 * equation types.
2224 */
2225 if ((type == PNG_EQUATION_LINEAR && nparams != 2) ||
2226 (type == PNG_EQUATION_BASE_E && nparams != 3) ||
2227 (type == PNG_EQUATION_ARBITRARY && nparams != 3) ||
2228 (type == PNG_EQUATION_HYPERBOLIC && nparams != 4))
2229 {
2230 png_chunk_benign_error(png_ptr, "invalid parameter count");
2231 return;
2232 }
2233
2234 else if (type >= PNG_EQUATION_LAST)
2235 {
2236 png_chunk_benign_error(png_ptr, "unrecognized equation type");
2237 }
2238
2239 for (buf = units; *buf; buf++)
2240 /* Empty loop to move past the units string. */ ;
2241
2242 png_debug(3, "Allocating pCAL parameters array");
2243
2244 params = png_voidcast(png_charpp, png_malloc_warn(png_ptr,
2245 nparams * (sizeof (png_charp))));
2246
2247 if (params == NULL)
2248 {
2249 png_chunk_benign_error(png_ptr, "out of memory");
2250 return;
2251 }
2252
2253 /* Get pointers to the start of each parameter string. */
2254 for (i = 0; i < nparams; i++)
2255 {
2256 buf++; /* Skip the null string terminator from previous parameter. */
2257
2258 png_debug1(3, "Reading pCAL parameter %d", i);
2259
2260 for (params[i] = (png_charp)buf; buf <= endptr && *buf != 0; buf++)
2261 /* Empty loop to move past each parameter string */ ;
2262
2263 /* Make sure we haven't run out of data yet */
2264 if (buf > endptr)
2265 {
2266 png_free(png_ptr, params);
2267 png_chunk_benign_error(png_ptr, "invalid data");
2268 return;
2269 }
2270 }
2271
2272 png_set_pCAL(png_ptr, info_ptr, (png_charp)buffer, X0, X1, type, nparams,
2273 (png_charp)units, params);
2274
2275 png_free(png_ptr, params);
2276 }
2277 #endif
2278
2279 #ifdef PNG_READ_sCAL_SUPPORTED
2280 /* Read the sCAL chunk */
2281 void /* PRIVATE */
2282 png_handle_sCAL(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2283 {
2284 png_bytep buffer;
2285 png_size_t i;
2286 int state;
2287
2288 png_debug(1, "in png_handle_sCAL");
2289
2290 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2291 png_chunk_error(png_ptr, "missing IHDR");
2292
2293 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2294 {
2295 png_crc_finish(png_ptr, length);
2296 png_chunk_benign_error(png_ptr, "out of place");
2297 return;
2298 }
2299
2300 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sCAL) != 0)
2301 {
2302 png_crc_finish(png_ptr, length);
2303 png_chunk_benign_error(png_ptr, "duplicate");
2304 return;
2305 }
2306
2307 /* Need unit type, width, \0, height: minimum 4 bytes */
2308 else if (length < 4)
2309 {
2310 png_crc_finish(png_ptr, length);
2311 png_chunk_benign_error(png_ptr, "invalid");
2312 return;
2313 }
2314
2315 png_debug1(2, "Allocating and reading sCAL chunk data (%u bytes)",
2316 length + 1);
2317
2318 buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/);
2319
2320 if (buffer == NULL)
2321 {
2322 png_chunk_benign_error(png_ptr, "out of memory");
2323 png_crc_finish(png_ptr, length);
2324 return;
2325 }
2326
2327 png_crc_read(png_ptr, buffer, length);
2328 buffer[length] = 0; /* Null terminate the last string */
2329
2330 if (png_crc_finish(png_ptr, 0) != 0)
2331 return;
2332
2333 /* Validate the unit. */
2334 if (buffer[0] != 1 && buffer[0] != 2)
2335 {
2336 png_chunk_benign_error(png_ptr, "invalid unit");
2337 return;
2338 }
2339
2340 /* Validate the ASCII numbers, need two ASCII numbers separated by
2341 * a '\0' and they need to fit exactly in the chunk data.
2342 */
2343 i = 1;
2344 state = 0;
2345
2346 if (png_check_fp_number((png_const_charp)buffer, length, &state, &i) == 0 ||
2347 i >= length || buffer[i++] != 0)
2348 png_chunk_benign_error(png_ptr, "bad width format");
2349
2350 else if (PNG_FP_IS_POSITIVE(state) == 0)
2351 png_chunk_benign_error(png_ptr, "non-positive width");
2352
2353 else
2354 {
2355 png_size_t heighti = i;
2356
2357 state = 0;
2358 if (png_check_fp_number((png_const_charp)buffer, length,
2359 &state, &i) == 0 || i != length)
2360 png_chunk_benign_error(png_ptr, "bad height format");
2361
2362 else if (PNG_FP_IS_POSITIVE(state) == 0)
2363 png_chunk_benign_error(png_ptr, "non-positive height");
2364
2365 else
2366 /* This is the (only) success case. */
2367 png_set_sCAL_s(png_ptr, info_ptr, buffer[0],
2368 (png_charp)buffer+1, (png_charp)buffer+heighti);
2369 }
2370 }
2371 #endif
2372
2373 #ifdef PNG_READ_tIME_SUPPORTED
2374 void /* PRIVATE */
2375 png_handle_tIME(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2376 {
2377 png_byte buf[7];
2378 png_time mod_time;
2379
2380 png_debug(1, "in png_handle_tIME");
2381
2382 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2383 png_chunk_error(png_ptr, "missing IHDR");
2384
2385 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tIME) != 0)
2386 {
2387 png_crc_finish(png_ptr, length);
2388 png_chunk_benign_error(png_ptr, "duplicate");
2389 return;
2390 }
2391
2392 if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2393 png_ptr->mode |= PNG_AFTER_IDAT;
2394
2395 if (length != 7)
2396 {
2397 png_crc_finish(png_ptr, length);
2398 png_chunk_benign_error(png_ptr, "invalid");
2399 return;
2400 }
2401
2402 png_crc_read(png_ptr, buf, 7);
2403
2404 if (png_crc_finish(png_ptr, 0) != 0)
2405 return;
2406
2407 mod_time.second = buf[6];
2408 mod_time.minute = buf[5];
2409 mod_time.hour = buf[4];
2410 mod_time.day = buf[3];
2411 mod_time.month = buf[2];
2412 mod_time.year = png_get_uint_16(buf);
2413
2414 png_set_tIME(png_ptr, info_ptr, &mod_time);
2415 }
2416 #endif
2417
2418 #ifdef PNG_READ_tEXt_SUPPORTED
2419 /* Note: this does not properly handle chunks that are > 64K under DOS */
2420 void /* PRIVATE */
2421 png_handle_tEXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2422 {
2423 png_text text_info;
2424 png_bytep buffer;
2425 png_charp key;
2426 png_charp text;
2427 png_uint_32 skip = 0;
2428
2429 png_debug(1, "in png_handle_tEXt");
2430
2431 #ifdef PNG_USER_LIMITS_SUPPORTED
2432 if (png_ptr->user_chunk_cache_max != 0)
2433 {
2434 if (png_ptr->user_chunk_cache_max == 1)
2435 {
2436 png_crc_finish(png_ptr, length);
2437 return;
2438 }
2439
2440 if (--png_ptr->user_chunk_cache_max == 1)
2441 {
2442 png_crc_finish(png_ptr, length);
2443 png_chunk_benign_error(png_ptr, "no space in chunk cache");
2444 return;
2445 }
2446 }
2447 #endif
2448
2449 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2450 png_chunk_error(png_ptr, "missing IHDR");
2451
2452 if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2453 png_ptr->mode |= PNG_AFTER_IDAT;
2454
2455 #ifdef PNG_MAX_MALLOC_64K
2456 if (length > 65535U)
2457 {
2458 png_crc_finish(png_ptr, length);
2459 png_chunk_benign_error(png_ptr, "too large to fit in memory");
2460 return;
2461 }
2462 #endif
2463
2464 buffer = png_read_buffer(png_ptr, length+1, 1/*warn*/);
2465
2466 if (buffer == NULL)
2467 {
2468 png_chunk_benign_error(png_ptr, "out of memory");
2469 return;
2470 }
2471
2472 png_crc_read(png_ptr, buffer, length);
2473
2474 if (png_crc_finish(png_ptr, skip) != 0)
2475 return;
2476
2477 key = (png_charp)buffer;
2478 key[length] = 0;
2479
2480 for (text = key; *text; text++)
2481 /* Empty loop to find end of key */ ;
2482
2483 if (text != key + length)
2484 text++;
2485
2486 text_info.compression = PNG_TEXT_COMPRESSION_NONE;
2487 text_info.key = key;
2488 text_info.lang = NULL;
2489 text_info.lang_key = NULL;
2490 text_info.itxt_length = 0;
2491 text_info.text = text;
2492 text_info.text_length = strlen(text);
2493
2494 if (png_set_text_2(png_ptr, info_ptr, &text_info, 1) != 0)
2495 png_warning(png_ptr, "Insufficient memory to process text chunk");
2496 }
2497 #endif
2498
2499 #ifdef PNG_READ_zTXt_SUPPORTED
2500 /* Note: this does not correctly handle chunks that are > 64K under DOS */
2501 void /* PRIVATE */
2502 png_handle_zTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2503 {
2504 png_const_charp errmsg = NULL;
2505 png_bytep buffer;
2506 png_uint_32 keyword_length;
2507
2508 png_debug(1, "in png_handle_zTXt");
2509
2510 #ifdef PNG_USER_LIMITS_SUPPORTED
2511 if (png_ptr->user_chunk_cache_max != 0)
2512 {
2513 if (png_ptr->user_chunk_cache_max == 1)
2514 {
2515 png_crc_finish(png_ptr, length);
2516 return;
2517 }
2518
2519 if (--png_ptr->user_chunk_cache_max == 1)
2520 {
2521 png_crc_finish(png_ptr, length);
2522 png_chunk_benign_error(png_ptr, "no space in chunk cache");
2523 return;
2524 }
2525 }
2526 #endif
2527
2528 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2529 png_chunk_error(png_ptr, "missing IHDR");
2530
2531 if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2532 png_ptr->mode |= PNG_AFTER_IDAT;
2533
2534 buffer = png_read_buffer(png_ptr, length, 2/*silent*/);
2535
2536 if (buffer == NULL)
2537 {
2538 png_crc_finish(png_ptr, length);
2539 png_chunk_benign_error(png_ptr, "out of memory");
2540 return;
2541 }
2542
2543 png_crc_read(png_ptr, buffer, length);
2544
2545 if (png_crc_finish(png_ptr, 0) != 0)
2546 return;
2547
2548 /* TODO: also check that the keyword contents match the spec! */
2549 for (keyword_length = 0;
2550 keyword_length < length && buffer[keyword_length] != 0;
2551 ++keyword_length)
2552 /* Empty loop to find end of name */ ;
2553
2554 if (keyword_length > 79 || keyword_length < 1)
2555 errmsg = "bad keyword";
2556
2557 /* zTXt must have some LZ data after the keyword, although it may expand to
2558 * zero bytes; we need a '\0' at the end of the keyword, the compression type
2559 * then the LZ data:
2560 */
2561 else if (keyword_length + 3 > length)
2562 errmsg = "truncated";
2563
2564 else if (buffer[keyword_length+1] != PNG_COMPRESSION_TYPE_BASE)
2565 errmsg = "unknown compression type";
2566
2567 else
2568 {
2569 png_alloc_size_t uncompressed_length = PNG_SIZE_MAX;
2570
2571 /* TODO: at present png_decompress_chunk imposes a single application
2572 * level memory limit, this should be split to different values for iCCP
2573 * and text chunks.
2574 */
2575 if (png_decompress_chunk(png_ptr, length, keyword_length+2,
2576 &uncompressed_length, 1/*terminate*/) == Z_STREAM_END)
2577 {
2578 png_text text;
2579
2580 /* It worked; png_ptr->read_buffer now looks like a tEXt chunk except
2581 * for the extra compression type byte and the fact that it isn't
2582 * necessarily '\0' terminated.
2583 */
2584 buffer = png_ptr->read_buffer;
2585 buffer[uncompressed_length+(keyword_length+2)] = 0;
2586
2587 text.compression = PNG_TEXT_COMPRESSION_zTXt;
2588 text.key = (png_charp)buffer;
2589 text.text = (png_charp)(buffer + keyword_length+2);
2590 text.text_length = uncompressed_length;
2591 text.itxt_length = 0;
2592 text.lang = NULL;
2593 text.lang_key = NULL;
2594
2595 if (png_set_text_2(png_ptr, info_ptr, &text, 1) != 0)
2596 errmsg = "insufficient memory";
2597 }
2598
2599 else
2600 errmsg = png_ptr->zstream.msg;
2601 }
2602
2603 if (errmsg != NULL)
2604 png_chunk_benign_error(png_ptr, errmsg);
2605 }
2606 #endif
2607
2608 #ifdef PNG_READ_iTXt_SUPPORTED
2609 /* Note: this does not correctly handle chunks that are > 64K under DOS */
2610 void /* PRIVATE */
2611 png_handle_iTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2612 {
2613 png_const_charp errmsg = NULL;
2614 png_bytep buffer;
2615 png_uint_32 prefix_length;
2616
2617 png_debug(1, "in png_handle_iTXt");
2618
2619 #ifdef PNG_USER_LIMITS_SUPPORTED
2620 if (png_ptr->user_chunk_cache_max != 0)
2621 {
2622 if (png_ptr->user_chunk_cache_max == 1)
2623 {
2624 png_crc_finish(png_ptr, length);
2625 return;
2626 }
2627
2628 if (--png_ptr->user_chunk_cache_max == 1)
2629 {
2630 png_crc_finish(png_ptr, length);
2631 png_chunk_benign_error(png_ptr, "no space in chunk cache");
2632 return;
2633 }
2634 }
2635 #endif
2636
2637 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2638 png_chunk_error(png_ptr, "missing IHDR");
2639
2640 if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2641 png_ptr->mode |= PNG_AFTER_IDAT;
2642
2643 buffer = png_read_buffer(png_ptr, length+1, 1/*warn*/);
2644
2645 if (buffer == NULL)
2646 {
2647 png_crc_finish(png_ptr, length);
2648 png_chunk_benign_error(png_ptr, "out of memory");
2649 return;
2650 }
2651
2652 png_crc_read(png_ptr, buffer, length);
2653
2654 if (png_crc_finish(png_ptr, 0) != 0)
2655 return;
2656
2657 /* First the keyword. */
2658 for (prefix_length=0;
2659 prefix_length < length && buffer[prefix_length] != 0;
2660 ++prefix_length)
2661 /* Empty loop */ ;
2662
2663 /* Perform a basic check on the keyword length here. */
2664 if (prefix_length > 79 || prefix_length < 1)
2665 errmsg = "bad keyword";
2666
2667 /* Expect keyword, compression flag, compression type, language, translated
2668 * keyword (both may be empty but are 0 terminated) then the text, which may
2669 * be empty.
2670 */
2671 else if (prefix_length + 5 > length)
2672 errmsg = "truncated";
2673
2674 else if (buffer[prefix_length+1] == 0 ||
2675 (buffer[prefix_length+1] == 1 &&
2676 buffer[prefix_length+2] == PNG_COMPRESSION_TYPE_BASE))
2677 {
2678 int compressed = buffer[prefix_length+1] != 0;
2679 png_uint_32 language_offset, translated_keyword_offset;
2680 png_alloc_size_t uncompressed_length = 0;
2681
2682 /* Now the language tag */
2683 prefix_length += 3;
2684 language_offset = prefix_length;
2685
2686 for (; prefix_length < length && buffer[prefix_length] != 0;
2687 ++prefix_length)
2688 /* Empty loop */ ;
2689
2690 /* WARNING: the length may be invalid here, this is checked below. */
2691 translated_keyword_offset = ++prefix_length;
2692
2693 for (; prefix_length < length && buffer[prefix_length] != 0;
2694 ++prefix_length)
2695 /* Empty loop */ ;
2696
2697 /* prefix_length should now be at the trailing '\0' of the translated
2698 * keyword, but it may already be over the end. None of this arithmetic
2699 * can overflow because chunks are at most 2^31 bytes long, but on 16-bit
2700 * systems the available allocation may overflow.
2701 */
2702 ++prefix_length;
2703
2704 if (compressed == 0 && prefix_length <= length)
2705 uncompressed_length = length - prefix_length;
2706
2707 else if (compressed != 0 && prefix_length < length)
2708 {
2709 uncompressed_length = PNG_SIZE_MAX;
2710
2711 /* TODO: at present png_decompress_chunk imposes a single application
2712 * level memory limit, this should be split to different values for
2713 * iCCP and text chunks.
2714 */
2715 if (png_decompress_chunk(png_ptr, length, prefix_length,
2716 &uncompressed_length, 1/*terminate*/) == Z_STREAM_END)
2717 buffer = png_ptr->read_buffer;
2718
2719 else
2720 errmsg = png_ptr->zstream.msg;
2721 }
2722
2723 else
2724 errmsg = "truncated";
2725
2726 if (errmsg == NULL)
2727 {
2728 png_text text;
2729
2730 buffer[uncompressed_length+prefix_length] = 0;
2731
2732 if (compressed == 0)
2733 text.compression = PNG_ITXT_COMPRESSION_NONE;
2734
2735 else
2736 text.compression = PNG_ITXT_COMPRESSION_zTXt;
2737
2738 text.key = (png_charp)buffer;
2739 text.lang = (png_charp)buffer + language_offset;
2740 text.lang_key = (png_charp)buffer + translated_keyword_offset;
2741 text.text = (png_charp)buffer + prefix_length;
2742 text.text_length = 0;
2743 text.itxt_length = uncompressed_length;
2744
2745 if (png_set_text_2(png_ptr, info_ptr, &text, 1) != 0)
2746 errmsg = "insufficient memory";
2747 }
2748 }
2749
2750 else
2751 errmsg = "bad compression info";
2752
2753 if (errmsg != NULL)
2754 png_chunk_benign_error(png_ptr, errmsg);
2755 }
2756 #endif
2757
2758 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
2759 /* Utility function for png_handle_unknown; set up png_ptr::unknown_chunk */
2760 static int
2761 png_cache_unknown_chunk(png_structrp png_ptr, png_uint_32 length)
2762 {
2763 png_alloc_size_t limit = PNG_SIZE_MAX;
2764
2765 if (png_ptr->unknown_chunk.data != NULL)
2766 {
2767 png_free(png_ptr, png_ptr->unknown_chunk.data);
2768 png_ptr->unknown_chunk.data = NULL;
2769 }
2770
2771 # ifdef PNG_SET_USER_LIMITS_SUPPORTED
2772 if (png_ptr->user_chunk_malloc_max > 0 &&
2773 png_ptr->user_chunk_malloc_max < limit)
2774 limit = png_ptr->user_chunk_malloc_max;
2775
2776 # elif PNG_USER_CHUNK_MALLOC_MAX > 0
2777 if (PNG_USER_CHUNK_MALLOC_MAX < limit)
2778 limit = PNG_USER_CHUNK_MALLOC_MAX;
2779 # endif
2780
2781 if (length <= limit)
2782 {
2783 PNG_CSTRING_FROM_CHUNK(png_ptr->unknown_chunk.name, png_ptr->chunk_name);
2784 /* The following is safe because of the PNG_SIZE_MAX init above */
2785 png_ptr->unknown_chunk.size = (png_size_t)length/*SAFE*/;
2786 /* 'mode' is a flag array, only the bottom four bits matter here */
2787 png_ptr->unknown_chunk.location = (png_byte)png_ptr->mode/*SAFE*/;
2788
2789 if (length == 0)
2790 png_ptr->unknown_chunk.data = NULL;
2791
2792 else
2793 {
2794 /* Do a 'warn' here - it is handled below. */
2795 png_ptr->unknown_chunk.data = png_voidcast(png_bytep,
2796 png_malloc_warn(png_ptr, length));
2797 }
2798 }
2799
2800 if (png_ptr->unknown_chunk.data == NULL && length > 0)
2801 {
2802 /* This is benign because we clean up correctly */
2803 png_crc_finish(png_ptr, length);
2804 png_chunk_benign_error(png_ptr, "unknown chunk exceeds memory limits");
2805 return 0;
2806 }
2807
2808 else
2809 {
2810 if (length > 0)
2811 png_crc_read(png_ptr, png_ptr->unknown_chunk.data, length);
2812 png_crc_finish(png_ptr, 0);
2813 return 1;
2814 }
2815 }
2816 #endif /* READ_UNKNOWN_CHUNKS */
2817
2818 /* Handle an unknown, or known but disabled, chunk */
2819 void /* PRIVATE */
2820 png_handle_unknown(png_structrp png_ptr, png_inforp info_ptr,
2821 png_uint_32 length, int keep)
2822 {
2823 int handled = 0; /* the chunk was handled */
2824
2825 png_debug(1, "in png_handle_unknown");
2826
2827 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
2828 /* NOTE: this code is based on the code in libpng-1.4.12 except for fixing
2829 * the bug which meant that setting a non-default behavior for a specific
2830 * chunk would be ignored (the default was always used unless a user
2831 * callback was installed).
2832 *
2833 * 'keep' is the value from the png_chunk_unknown_handling, the setting for
2834 * this specific chunk_name, if PNG_HANDLE_AS_UNKNOWN_SUPPORTED, if not it
2835 * will always be PNG_HANDLE_CHUNK_AS_DEFAULT and it needs to be set here.
2836 * This is just an optimization to avoid multiple calls to the lookup
2837 * function.
2838 */
2839 # ifndef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
2840 # ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
2841 keep = png_chunk_unknown_handling(png_ptr, png_ptr->chunk_name);
2842 # endif
2843 # endif
2844
2845 /* One of the following methods will read the chunk or skip it (at least one
2846 * of these is always defined because this is the only way to switch on
2847 * PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
2848 */
2849 # ifdef PNG_READ_USER_CHUNKS_SUPPORTED
2850 /* The user callback takes precedence over the chunk keep value, but the
2851 * keep value is still required to validate a save of a critical chunk.
2852 */
2853 if (png_ptr->read_user_chunk_fn != NULL)
2854 {
2855 if (png_cache_unknown_chunk(png_ptr, length) != 0)
2856 {
2857 /* Callback to user unknown chunk handler */
2858 int ret = (*(png_ptr->read_user_chunk_fn))(png_ptr,
2859 &png_ptr->unknown_chunk);
2860
2861 /* ret is:
2862 * negative: An error occurred; png_chunk_error will be called.
2863 * zero: The chunk was not handled, the chunk will be discarded
2864 * unless png_set_keep_unknown_chunks has been used to set
2865 * a 'keep' behavior for this particular chunk, in which
2866 * case that will be used. A critical chunk will cause an
2867 * error at this point unless it is to be saved.
2868 * positive: The chunk was handled, libpng will ignore/discard it.
2869 */
2870 if (ret < 0)
2871 png_chunk_error(png_ptr, "error in user chunk");
2872
2873 else if (ret == 0)
2874 {
2875 /* If the keep value is 'default' or 'never' override it, but
2876 * still error out on critical chunks unless the keep value is
2877 * 'always' While this is weird it is the behavior in 1.4.12.
2878 * A possible improvement would be to obey the value set for the
2879 * chunk, but this would be an API change that would probably
2880 * damage some applications.
2881 *
2882 * The png_app_warning below catches the case that matters, where
2883 * the application has not set specific save or ignore for this
2884 * chunk or global save or ignore.
2885 */
2886 if (keep < PNG_HANDLE_CHUNK_IF_SAFE)
2887 {
2888 # ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
2889 if (png_ptr->unknown_default < PNG_HANDLE_CHUNK_IF_SAFE)
2890 {
2891 png_chunk_warning(png_ptr, "Saving unknown chunk:");
2892 png_app_warning(png_ptr,
2893 "forcing save of an unhandled chunk;"
2894 " please call png_set_keep_unknown_chunks");
2895 /* with keep = PNG_HANDLE_CHUNK_IF_SAFE */
2896 }
2897 # endif
2898 keep = PNG_HANDLE_CHUNK_IF_SAFE;
2899 }
2900 }
2901
2902 else /* chunk was handled */
2903 {
2904 handled = 1;
2905 /* Critical chunks can be safely discarded at this point. */
2906 keep = PNG_HANDLE_CHUNK_NEVER;
2907 }
2908 }
2909
2910 else
2911 keep = PNG_HANDLE_CHUNK_NEVER; /* insufficient memory */
2912 }
2913
2914 else
2915 /* Use the SAVE_UNKNOWN_CHUNKS code or skip the chunk */
2916 # endif /* READ_USER_CHUNKS */
2917
2918 # ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED
2919 {
2920 /* keep is currently just the per-chunk setting, if there was no
2921 * setting change it to the global default now (not that this may
2922 * still be AS_DEFAULT) then obtain the cache of the chunk if required,
2923 * if not simply skip the chunk.
2924 */
2925 if (keep == PNG_HANDLE_CHUNK_AS_DEFAULT)
2926 keep = png_ptr->unknown_default;
2927
2928 if (keep == PNG_HANDLE_CHUNK_ALWAYS ||
2929 (keep == PNG_HANDLE_CHUNK_IF_SAFE &&
2930 PNG_CHUNK_ANCILLARY(png_ptr->chunk_name)))
2931 {
2932 if (png_cache_unknown_chunk(png_ptr, length) == 0)
2933 keep = PNG_HANDLE_CHUNK_NEVER;
2934 }
2935
2936 else
2937 png_crc_finish(png_ptr, length);
2938 }
2939 # else
2940 # ifndef PNG_READ_USER_CHUNKS_SUPPORTED
2941 # error no method to support READ_UNKNOWN_CHUNKS
2942 # endif
2943
2944 {
2945 /* If here there is no read callback pointer set and no support is
2946 * compiled in to just save the unknown chunks, so simply skip this
2947 * chunk. If 'keep' is something other than AS_DEFAULT or NEVER then
2948 * the app has erroneously asked for unknown chunk saving when there
2949 * is no support.
2950 */
2951 if (keep > PNG_HANDLE_CHUNK_NEVER)
2952 png_app_error(png_ptr, "no unknown chunk support available");
2953
2954 png_crc_finish(png_ptr, length);
2955 }
2956 # endif
2957
2958 # ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
2959 /* Now store the chunk in the chunk list if appropriate, and if the limits
2960 * permit it.
2961 */
2962 if (keep == PNG_HANDLE_CHUNK_ALWAYS ||
2963 (keep == PNG_HANDLE_CHUNK_IF_SAFE &&
2964 PNG_CHUNK_ANCILLARY(png_ptr->chunk_name)))
2965 {
2966 # ifdef PNG_USER_LIMITS_SUPPORTED
2967 switch (png_ptr->user_chunk_cache_max)
2968 {
2969 case 2:
2970 png_ptr->user_chunk_cache_max = 1;
2971 png_chunk_benign_error(png_ptr, "no space in chunk cache");
2972 /* FALL THROUGH */
2973 case 1:
2974 /* NOTE: prior to 1.6.0 this case resulted in an unknown critical
2975 * chunk being skipped, now there will be a hard error below.
2976 */
2977 break;
2978
2979 default: /* not at limit */
2980 --(png_ptr->user_chunk_cache_max);
2981 /* FALL THROUGH */
2982 case 0: /* no limit */
2983 # endif /* USER_LIMITS */
2984 /* Here when the limit isn't reached or when limits are compiled
2985 * out; store the chunk.
2986 */
2987 png_set_unknown_chunks(png_ptr, info_ptr,
2988 &png_ptr->unknown_chunk, 1);
2989 handled = 1;
2990 # ifdef PNG_USER_LIMITS_SUPPORTED
2991 break;
2992 }
2993 # endif
2994 }
2995 # else /* no store support: the chunk must be handled by the user callback */
2996 PNG_UNUSED(info_ptr)
2997 # endif
2998
2999 /* Regardless of the error handling below the cached data (if any) can be
3000 * freed now. Notice that the data is not freed if there is a png_error, but
3001 * it will be freed by destroy_read_struct.
3002 */
3003 if (png_ptr->unknown_chunk.data != NULL)
3004 png_free(png_ptr, png_ptr->unknown_chunk.data);
3005 png_ptr->unknown_chunk.data = NULL;
3006
3007 #else /* !PNG_READ_UNKNOWN_CHUNKS_SUPPORTED */
3008 /* There is no support to read an unknown chunk, so just skip it. */
3009 png_crc_finish(png_ptr, length);
3010 PNG_UNUSED(info_ptr)
3011 PNG_UNUSED(keep)
3012 #endif /* !READ_UNKNOWN_CHUNKS */
3013
3014 /* Check for unhandled critical chunks */
3015 if (handled == 0 && PNG_CHUNK_CRITICAL(png_ptr->chunk_name))
3016 png_chunk_error(png_ptr, "unhandled critical chunk");
3017 }
3018
3019 /* This function is called to verify that a chunk name is valid.
3020 * This function can't have the "critical chunk check" incorporated
3021 * into it, since in the future we will need to be able to call user
3022 * functions to handle unknown critical chunks after we check that
3023 * the chunk name itself is valid.
3024 */
3025
3026 /* Bit hacking: the test for an invalid byte in the 4 byte chunk name is:
3027 *
3028 * ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97))
3029 */
3030
3031 void /* PRIVATE */
3032 png_check_chunk_name(png_structrp png_ptr, png_uint_32 chunk_name)
3033 {
3034 int i;
3035
3036 png_debug(1, "in png_check_chunk_name");
3037
3038 for (i=1; i<=4; ++i)
3039 {
3040 int c = chunk_name & 0xff;
3041
3042 if (c < 65 || c > 122 || (c > 90 && c < 97))
3043 png_chunk_error(png_ptr, "invalid chunk type");
3044
3045 chunk_name >>= 8;
3046 }
3047 }
3048
3049 /* Combines the row recently read in with the existing pixels in the row. This
3050 * routine takes care of alpha and transparency if requested. This routine also
3051 * handles the two methods of progressive display of interlaced images,
3052 * depending on the 'display' value; if 'display' is true then the whole row
3053 * (dp) is filled from the start by replicating the available pixels. If
3054 * 'display' is false only those pixels present in the pass are filled in.
3055 */
3056 void /* PRIVATE */
3057 png_combine_row(png_const_structrp png_ptr, png_bytep dp, int display)
3058 {
3059 unsigned int pixel_depth = png_ptr->transformed_pixel_depth;
3060 png_const_bytep sp = png_ptr->row_buf + 1;
3061 png_alloc_size_t row_width = png_ptr->width;
3062 unsigned int pass = png_ptr->pass;
3063 png_bytep end_ptr = 0;
3064 png_byte end_byte = 0;
3065 unsigned int end_mask;
3066
3067 png_debug(1, "in png_combine_row");
3068
3069 /* Added in 1.5.6: it should not be possible to enter this routine until at
3070 * least one row has been read from the PNG data and transformed.
3071 */
3072 if (pixel_depth == 0)
3073 png_error(png_ptr, "internal row logic error");
3074
3075 /* Added in 1.5.4: the pixel depth should match the information returned by
3076 * any call to png_read_update_info at this point. Do not continue if we got
3077 * this wrong.
3078 */
3079 if (png_ptr->info_rowbytes != 0 && png_ptr->info_rowbytes !=
3080 PNG_ROWBYTES(pixel_depth, row_width))
3081 png_error(png_ptr, "internal row size calculation error");
3082
3083 /* Don't expect this to ever happen: */
3084 if (row_width == 0)
3085 png_error(png_ptr, "internal row width error");
3086
3087 /* Preserve the last byte in cases where only part of it will be overwritten,
3088 * the multiply below may overflow, we don't care because ANSI-C guarantees
3089 * we get the low bits.
3090 */
3091 end_mask = (pixel_depth * row_width) & 7;
3092 if (end_mask != 0)
3093 {
3094 /* end_ptr == NULL is a flag to say do nothing */
3095 end_ptr = dp + PNG_ROWBYTES(pixel_depth, row_width) - 1;
3096 end_byte = *end_ptr;
3097 # ifdef PNG_READ_PACKSWAP_SUPPORTED
3098 if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
3099 /* little-endian byte */
3100 end_mask = 0xff << end_mask;
3101
3102 else /* big-endian byte */
3103 # endif
3104 end_mask = 0xff >> end_mask;
3105 /* end_mask is now the bits to *keep* from the destination row */
3106 }
3107
3108 /* For non-interlaced images this reduces to a memcpy(). A memcpy()
3109 * will also happen if interlacing isn't supported or if the application
3110 * does not call png_set_interlace_handling(). In the latter cases the
3111 * caller just gets a sequence of the unexpanded rows from each interlace
3112 * pass.
3113 */
3114 #ifdef PNG_READ_INTERLACING_SUPPORTED
3115 if (png_ptr->interlaced != 0 &&
3116 (png_ptr->transformations & PNG_INTERLACE) != 0 &&
3117 pass < 6 && (display == 0 ||
3118 /* The following copies everything for 'display' on passes 0, 2 and 4. */
3119 (display == 1 && (pass & 1) != 0)))
3120 {
3121 /* Narrow images may have no bits in a pass; the caller should handle
3122 * this, but this test is cheap:
3123 */
3124 if (row_width <= PNG_PASS_START_COL(pass))
3125 return;
3126
3127 if (pixel_depth < 8)
3128 {
3129 /* For pixel depths up to 4 bpp the 8-pixel mask can be expanded to fit
3130 * into 32 bits, then a single loop over the bytes using the four byte
3131 * values in the 32-bit mask can be used. For the 'display' option the
3132 * expanded mask may also not require any masking within a byte. To
3133 * make this work the PACKSWAP option must be taken into account - it
3134 * simply requires the pixels to be reversed in each byte.
3135 *
3136 * The 'regular' case requires a mask for each of the first 6 passes,
3137 * the 'display' case does a copy for the even passes in the range
3138 * 0..6. This has already been handled in the test above.
3139 *
3140 * The masks are arranged as four bytes with the first byte to use in
3141 * the lowest bits (little-endian) regardless of the order (PACKSWAP or
3142 * not) of the pixels in each byte.
3143 *
3144 * NOTE: the whole of this logic depends on the caller of this function
3145 * only calling it on rows appropriate to the pass. This function only
3146 * understands the 'x' logic; the 'y' logic is handled by the caller.
3147 *
3148 * The following defines allow generation of compile time constant bit
3149 * masks for each pixel depth and each possibility of swapped or not
3150 * swapped bytes. Pass 'p' is in the range 0..6; 'x', a pixel index,
3151 * is in the range 0..7; and the result is 1 if the pixel is to be
3152 * copied in the pass, 0 if not. 'S' is for the sparkle method, 'B'
3153 * for the block method.
3154 *
3155 * With some compilers a compile time expression of the general form:
3156 *
3157 * (shift >= 32) ? (a >> (shift-32)) : (b >> shift)
3158 *
3159 * Produces warnings with values of 'shift' in the range 33 to 63
3160 * because the right hand side of the ?: expression is evaluated by
3161 * the compiler even though it isn't used. Microsoft Visual C (various
3162 * versions) and the Intel C compiler are known to do this. To avoid
3163 * this the following macros are used in 1.5.6. This is a temporary
3164 * solution to avoid destabilizing the code during the release process.
3165 */
3166 # if PNG_USE_COMPILE_TIME_MASKS
3167 # define PNG_LSR(x,s) ((x)>>((s) & 0x1f))
3168 # define PNG_LSL(x,s) ((x)<<((s) & 0x1f))
3169 # else
3170 # define PNG_LSR(x,s) ((x)>>(s))
3171 # define PNG_LSL(x,s) ((x)<<(s))
3172 # endif
3173 # define S_COPY(p,x) (((p)<4 ? PNG_LSR(0x80088822,(3-(p))*8+(7-(x))) :\
3174 PNG_LSR(0xaa55ff00,(7-(p))*8+(7-(x)))) & 1)
3175 # define B_COPY(p,x) (((p)<4 ? PNG_LSR(0xff0fff33,(3-(p))*8+(7-(x))) :\
3176 PNG_LSR(0xff55ff00,(7-(p))*8+(7-(x)))) & 1)
3177
3178 /* Return a mask for pass 'p' pixel 'x' at depth 'd'. The mask is
3179 * little endian - the first pixel is at bit 0 - however the extra
3180 * parameter 's' can be set to cause the mask position to be swapped
3181 * within each byte, to match the PNG format. This is done by XOR of
3182 * the shift with 7, 6 or 4 for bit depths 1, 2 and 4.
3183 */
3184 # define PIXEL_MASK(p,x,d,s) \
3185 (PNG_LSL(((PNG_LSL(1U,(d)))-1),(((x)*(d))^((s)?8-(d):0))))
3186
3187 /* Hence generate the appropriate 'block' or 'sparkle' pixel copy mask.
3188 */
3189 # define S_MASKx(p,x,d,s) (S_COPY(p,x)?PIXEL_MASK(p,x,d,s):0)
3190 # define B_MASKx(p,x,d,s) (B_COPY(p,x)?PIXEL_MASK(p,x,d,s):0)
3191
3192 /* Combine 8 of these to get the full mask. For the 1-bpp and 2-bpp
3193 * cases the result needs replicating, for the 4-bpp case the above
3194 * generates a full 32 bits.
3195 */
3196 # define MASK_EXPAND(m,d) ((m)*((d)==1?0x01010101:((d)==2?0x00010001:1)))
3197
3198 # define S_MASK(p,d,s) MASK_EXPAND(S_MASKx(p,0,d,s) + S_MASKx(p,1,d,s) +\
3199 S_MASKx(p,2,d,s) + S_MASKx(p,3,d,s) + S_MASKx(p,4,d,s) +\
3200 S_MASKx(p,5,d,s) + S_MASKx(p,6,d,s) + S_MASKx(p,7,d,s), d)
3201
3202 # define B_MASK(p,d,s) MASK_EXPAND(B_MASKx(p,0,d,s) + B_MASKx(p,1,d,s) +\
3203 B_MASKx(p,2,d,s) + B_MASKx(p,3,d,s) + B_MASKx(p,4,d,s) +\
3204 B_MASKx(p,5,d,s) + B_MASKx(p,6,d,s) + B_MASKx(p,7,d,s), d)
3205
3206 #if PNG_USE_COMPILE_TIME_MASKS
3207 /* Utility macros to construct all the masks for a depth/swap
3208 * combination. The 's' parameter says whether the format is PNG
3209 * (big endian bytes) or not. Only the three odd-numbered passes are
3210 * required for the display/block algorithm.
3211 */
3212 # define S_MASKS(d,s) { S_MASK(0,d,s), S_MASK(1,d,s), S_MASK(2,d,s),\
3213 S_MASK(3,d,s), S_MASK(4,d,s), S_MASK(5,d,s) }
3214
3215 # define B_MASKS(d,s) { B_MASK(1,d,s), B_MASK(3,d,s), B_MASK(5,d,s) }
3216