1 2 /* pngrutil.c - utilities to read a PNG file 3 * 4 * Last changed in libpng 1.6.33 [September 28, 2017] 5 * Copyright (c) 1998-2002,2004,2006-2017 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 (png_int_32)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 /* Check for too-large chunk length */ 185 png_check_chunk_length(png_ptr, length); 186 187 #ifdef PNG_IO_STATE_SUPPORTED 188 png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_DATA; 189 #endif 190 191 return length; 192 } 193 194 /* Read data, and (optionally) run it through the CRC. */ 195 void /* PRIVATE */ 196 png_crc_read(png_structrp png_ptr, png_bytep buf, png_uint_32 length) 197 { 198 if (png_ptr == NULL) 199 return; 200 201 png_read_data(png_ptr, buf, length); 202 png_calculate_crc(png_ptr, buf, length); 203 } 204 205 /* Optionally skip data and then check the CRC. Depending on whether we 206 * are reading an ancillary or critical chunk, and how the program has set 207 * things up, we may calculate the CRC on the data and print a message. 208 * Returns '1' if there was a CRC error, '0' otherwise. 209 */ 210 int /* PRIVATE */ 211 png_crc_finish(png_structrp png_ptr, png_uint_32 skip) 212 { 213 /* The size of the local buffer for inflate is a good guess as to a 214 * reasonable size to use for buffering reads from the application. 215 */ 216 while (skip > 0) 217 { 218 png_uint_32 len; 219 png_byte tmpbuf[PNG_INFLATE_BUF_SIZE]; 220 221 len = (sizeof tmpbuf); 222 if (len > skip) 223 len = skip; 224 skip -= len; 225 226 png_crc_read(png_ptr, tmpbuf, len); 227 } 228 229 if (png_crc_error(png_ptr) != 0) 230 { 231 if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name) != 0 ? 232 (png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) == 0 : 233 (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_USE) != 0) 234 { 235 png_chunk_warning(png_ptr, "CRC error"); 236 } 237 238 else 239 png_chunk_error(png_ptr, "CRC error"); 240 241 return (1); 242 } 243 244 return (0); 245 } 246 247 /* Compare the CRC stored in the PNG file with that calculated by libpng from 248 * the data it has read thus far. 249 */ 250 int /* PRIVATE */ 251 png_crc_error(png_structrp png_ptr) 252 { 253 png_byte crc_bytes[4]; 254 png_uint_32 crc; 255 int need_crc = 1; 256 257 if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name) != 0) 258 { 259 if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) == 260 (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN)) 261 need_crc = 0; 262 } 263 264 else /* critical */ 265 { 266 if ((png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE) != 0) 267 need_crc = 0; 268 } 269 270 #ifdef PNG_IO_STATE_SUPPORTED 271 png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_CRC; 272 #endif 273 274 /* The chunk CRC must be serialized in a single I/O call. */ 275 png_read_data(png_ptr, crc_bytes, 4); 276 277 if (need_crc != 0) 278 { 279 crc = png_get_uint_32(crc_bytes); 280 return ((int)(crc != png_ptr->crc)); 281 } 282 283 else 284 return (0); 285 } 286 287 #if defined(PNG_READ_iCCP_SUPPORTED) || defined(PNG_READ_iTXt_SUPPORTED) ||\ 288 defined(PNG_READ_pCAL_SUPPORTED) || defined(PNG_READ_sCAL_SUPPORTED) ||\ 289 defined(PNG_READ_sPLT_SUPPORTED) || defined(PNG_READ_tEXt_SUPPORTED) ||\ 290 defined(PNG_READ_zTXt_SUPPORTED) || defined(PNG_SEQUENTIAL_READ_SUPPORTED) 291 /* Manage the read buffer; this simply reallocates the buffer if it is not small 292 * enough (or if it is not allocated). The routine returns a pointer to the 293 * buffer; if an error occurs and 'warn' is set the routine returns NULL, else 294 * it will call png_error (via png_malloc) on failure. (warn == 2 means 295 * 'silent'). 296 */ 297 static png_bytep 298 png_read_buffer(png_structrp png_ptr, png_alloc_size_t new_size, int warn) 299 { 300 png_bytep buffer = png_ptr->read_buffer; 301 302 if (buffer != NULL && new_size > png_ptr->read_buffer_size) 303 { 304 png_ptr->read_buffer = NULL; 305 png_ptr->read_buffer = NULL; 306 png_ptr->read_buffer_size = 0; 307 png_free(png_ptr, buffer); 308 buffer = NULL; 309 } 310 311 if (buffer == NULL) 312 { 313 buffer = png_voidcast(png_bytep, png_malloc_base(png_ptr, new_size)); 314 315 if (buffer != NULL) 316 { 317 memset(buffer, 0, new_size); /* just in case */ 318 png_ptr->read_buffer = buffer; 319 png_ptr->read_buffer_size = new_size; 320 } 321 322 else if (warn < 2) /* else silent */ 323 { 324 if (warn != 0) 325 png_chunk_warning(png_ptr, "insufficient memory to read chunk"); 326 327 else 328 png_chunk_error(png_ptr, "insufficient memory to read chunk"); 329 } 330 } 331 332 return buffer; 333 } 334 #endif /* READ_iCCP|iTXt|pCAL|sCAL|sPLT|tEXt|zTXt|SEQUENTIAL_READ */ 335 336 /* png_inflate_claim: claim the zstream for some nefarious purpose that involves 337 * decompression. Returns Z_OK on success, else a zlib error code. It checks 338 * the owner but, in final release builds, just issues a warning if some other 339 * chunk apparently owns the stream. Prior to release it does a png_error. 340 */ 341 static int 342 png_inflate_claim(png_structrp png_ptr, png_uint_32 owner) 343 { 344 if (png_ptr->zowner != 0) 345 { 346 char msg[64]; 347 348 PNG_STRING_FROM_CHUNK(msg, png_ptr->zowner); 349 /* So the message that results is "<chunk> using zstream"; this is an 350 * internal error, but is very useful for debugging. i18n requirements 351 * are minimal. 352 */ 353 (void)png_safecat(msg, (sizeof msg), 4, " using zstream"); 354 #if PNG_RELEASE_BUILD 355 png_chunk_warning(png_ptr, msg); 356 png_ptr->zowner = 0; 357 #else 358 png_chunk_error(png_ptr, msg); 359 #endif 360 } 361 362 /* Implementation note: unlike 'png_deflate_claim' this internal function 363 * does not take the size of the data as an argument. Some efficiency could 364 * be gained by using this when it is known *if* the zlib stream itself does 365 * not record the number; however, this is an illusion: the original writer 366 * of the PNG may have selected a lower window size, and we really must 367 * follow that because, for systems with with limited capabilities, we 368 * would otherwise reject the application's attempts to use a smaller window 369 * size (zlib doesn't have an interface to say "this or lower"!). 370 * 371 * inflateReset2 was added to zlib 1.2.4; before this the window could not be 372 * reset, therefore it is necessary to always allocate the maximum window 373 * size with earlier zlibs just in case later compressed chunks need it. 374 */ 375 { 376 int ret; /* zlib return code */ 377 #if ZLIB_VERNUM >= 0x1240 378 int window_bits = 0; 379 380 # if defined(PNG_SET_OPTION_SUPPORTED) && defined(PNG_MAXIMUM_INFLATE_WINDOW) 381 if (((png_ptr->options >> PNG_MAXIMUM_INFLATE_WINDOW) & 3) == 382 PNG_OPTION_ON) 383 { 384 window_bits = 15; 385 png_ptr->zstream_start = 0; /* fixed window size */ 386 } 387 388 else 389 { 390 png_ptr->zstream_start = 1; 391 } 392 # endif 393 394 #endif /* ZLIB_VERNUM >= 0x1240 */ 395 396 /* Set this for safety, just in case the previous owner left pointers to 397 * memory allocations. 398 */ 399 png_ptr->zstream.next_in = NULL; 400 png_ptr->zstream.avail_in = 0; 401 png_ptr->zstream.next_out = NULL; 402 png_ptr->zstream.avail_out = 0; 403 404 if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0) 405 { 406 #if ZLIB_VERNUM >= 0x1240 407 ret = inflateReset2(&png_ptr->zstream, window_bits); 408 #else 409 ret = inflateReset(&png_ptr->zstream); 410 #endif 411 } 412 413 else 414 { 415 #if ZLIB_VERNUM >= 0x1240 416 ret = inflateInit2(&png_ptr->zstream, window_bits); 417 #else 418 ret = inflateInit(&png_ptr->zstream); 419 #endif 420 421 if (ret == Z_OK) 422 png_ptr->flags |= PNG_FLAG_ZSTREAM_INITIALIZED; 423 } 424 425 #if ZLIB_VERNUM >= 0x1290 && \ 426 defined(PNG_SET_OPTION_SUPPORTED) && defined(PNG_IGNORE_ADLER32) 427 if (((png_ptr->options >> PNG_IGNORE_ADLER32) & 3) == PNG_OPTION_ON) 428 /* Turn off validation of the ADLER32 checksum in IDAT chunks */ 429 ret = inflateValidate(&png_ptr->zstream, 0); 430 #endif 431 432 if (ret == Z_OK) 433 png_ptr->zowner = owner; 434 435 else 436 png_zstream_error(png_ptr, ret); 437 438 return ret; 439 } 440 441 #ifdef window_bits 442 # undef window_bits 443 #endif 444 } 445 446 #if ZLIB_VERNUM >= 0x1240 447 /* Handle the start of the inflate stream if we called inflateInit2(strm,0); 448 * in this case some zlib versions skip validation of the CINFO field and, in 449 * certain circumstances, libpng may end up displaying an invalid image, in 450 * contrast to implementations that call zlib in the normal way (e.g. libpng 451 * 1.5). 452 */ 453 int /* PRIVATE */ 454 png_zlib_inflate(png_structrp png_ptr, int flush) 455 { 456 if (png_ptr->zstream_start && png_ptr->zstream.avail_in > 0) 457 { 458 if ((*png_ptr->zstream.next_in >> 4) > 7) 459 { 460 png_ptr->zstream.msg = "invalid window size (libpng)"; 461 return Z_DATA_ERROR; 462 } 463 464 png_ptr->zstream_start = 0; 465 } 466 467 return inflate(&png_ptr->zstream, flush); 468 } 469 #endif /* Zlib >= 1.2.4 */ 470 471 #ifdef PNG_READ_COMPRESSED_TEXT_SUPPORTED 472 #if defined(PNG_READ_zTXt_SUPPORTED) || defined (PNG_READ_iTXt_SUPPORTED) 473 /* png_inflate now returns zlib error codes including Z_OK and Z_STREAM_END to 474 * allow the caller to do multiple calls if required. If the 'finish' flag is 475 * set Z_FINISH will be passed to the final inflate() call and Z_STREAM_END must 476 * be returned or there has been a problem, otherwise Z_SYNC_FLUSH is used and 477 * Z_OK or Z_STREAM_END will be returned on success. 478 * 479 * The input and output sizes are updated to the actual amounts of data consumed 480 * or written, not the amount available (as in a z_stream). The data pointers 481 * are not changed, so the next input is (data+input_size) and the next 482 * available output is (output+output_size). 483 */ 484 static int 485 png_inflate(png_structrp png_ptr, png_uint_32 owner, int finish, 486 /* INPUT: */ png_const_bytep input, png_uint_32p input_size_ptr, 487 /* OUTPUT: */ png_bytep output, png_alloc_size_t *output_size_ptr) 488 { 489 if (png_ptr->zowner == owner) /* Else not claimed */ 490 { 491 int ret; 492 png_alloc_size_t avail_out = *output_size_ptr; 493 png_uint_32 avail_in = *input_size_ptr; 494 495 /* zlib can't necessarily handle more than 65535 bytes at once (i.e. it 496 * can't even necessarily handle 65536 bytes) because the type uInt is 497 * "16 bits or more". Consequently it is necessary to chunk the input to 498 * zlib. This code uses ZLIB_IO_MAX, from pngpriv.h, as the maximum (the 499 * maximum value that can be stored in a uInt.) It is possible to set 500 * ZLIB_IO_MAX to a lower value in pngpriv.h and this may sometimes have 501 * a performance advantage, because it reduces the amount of data accessed 502 * at each step and that may give the OS more time to page it in. 503 */ 504 png_ptr->zstream.next_in = PNGZ_INPUT_CAST(input); 505 /* avail_in and avail_out are set below from 'size' */ 506 png_ptr->zstream.avail_in = 0; 507 png_ptr->zstream.avail_out = 0; 508 509 /* Read directly into the output if it is available (this is set to 510 * a local buffer below if output is NULL). 511 */ 512 if (output != NULL) 513 png_ptr->zstream.next_out = output; 514 515 do 516 { 517 uInt avail; 518 Byte local_buffer[PNG_INFLATE_BUF_SIZE]; 519 520 /* zlib INPUT BUFFER */ 521 /* The setting of 'avail_in' used to be outside the loop; by setting it 522 * inside it is possible to chunk the input to zlib and simply rely on 523 * zlib to advance the 'next_in' pointer. This allows arbitrary 524 * amounts of data to be passed through zlib at the unavoidable cost of 525 * requiring a window save (memcpy of up to 32768 output bytes) 526 * every ZLIB_IO_MAX input bytes. 527 */ 528 avail_in += png_ptr->zstream.avail_in; /* not consumed last time */ 529 530 avail = ZLIB_IO_MAX; 531 532 if (avail_in < avail) 533 avail = (uInt)avail_in; /* safe: < than ZLIB_IO_MAX */ 534 535 avail_in -= avail; 536 png_ptr->zstream.avail_in = avail; 537 538 /* zlib OUTPUT BUFFER */ 539 avail_out += png_ptr->zstream.avail_out; /* not written last time */ 540 541 avail = ZLIB_IO_MAX; /* maximum zlib can process */ 542 543 if (output == NULL) 544 { 545 /* Reset the output buffer each time round if output is NULL and 546 * make available the full buffer, up to 'remaining_space' 547 */ 548 png_ptr->zstream.next_out = local_buffer; 549 if ((sizeof local_buffer) < avail) 550 avail = (sizeof local_buffer); 551 } 552 553 if (avail_out < avail) 554 avail = (uInt)avail_out; /* safe: < ZLIB_IO_MAX */ 555 556 png_ptr->zstream.avail_out = avail; 557 avail_out -= avail; 558 559 /* zlib inflate call */ 560 /* In fact 'avail_out' may be 0 at this point, that happens at the end 561 * of the read when the final LZ end code was not passed at the end of 562 * the previous chunk of input data. Tell zlib if we have reached the 563 * end of the output buffer. 564 */ 565 ret = PNG_INFLATE(png_ptr, avail_out > 0 ? Z_NO_FLUSH : 566 (finish ? Z_FINISH : Z_SYNC_FLUSH)); 567 } while (ret == Z_OK); 568 569 /* For safety kill the local buffer pointer now */ 570 if (output == NULL) 571 png_ptr->zstream.next_out = NULL; 572 573 /* Claw back the 'size' and 'remaining_space' byte counts. */ 574 avail_in += png_ptr->zstream.avail_in; 575 avail_out += png_ptr->zstream.avail_out; 576 577 /* Update the input and output sizes; the updated values are the amount 578 * consumed or written, effectively the inverse of what zlib uses. 579 */ 580 if (avail_out > 0) 581 *output_size_ptr -= avail_out; 582 583 if (avail_in > 0) 584 *input_size_ptr -= avail_in; 585 586 /* Ensure png_ptr->zstream.msg is set (even in the success case!) */ 587 png_zstream_error(png_ptr, ret); 588 return ret; 589 } 590 591 else 592 { 593 /* This is a bad internal error. The recovery assigns to the zstream msg 594 * pointer, which is not owned by the caller, but this is safe; it's only 595 * used on errors! 596 */ 597 png_ptr->zstream.msg = PNGZ_MSG_CAST("zstream unclaimed"); 598 return Z_STREAM_ERROR; 599 } 600 } 601 602 /* 603 * Decompress trailing data in a chunk. The assumption is that read_buffer 604 * points at an allocated area holding the contents of a chunk with a 605 * trailing compressed part. What we get back is an allocated area 606 * holding the original prefix part and an uncompressed version of the 607 * trailing part (the malloc area passed in is freed). 608 */ 609 static int 610 png_decompress_chunk(png_structrp png_ptr, 611 png_uint_32 chunklength, png_uint_32 prefix_size, 612 png_alloc_size_t *newlength /* must be initialized to the maximum! */, 613 int terminate /*add a '\0' to the end of the uncompressed data*/) 614 { 615 /* TODO: implement different limits for different types of chunk. 616 * 617 * The caller supplies *newlength set to the maximum length of the 618 * uncompressed data, but this routine allocates space for the prefix and 619 * maybe a '\0' terminator too. We have to assume that 'prefix_size' is 620 * limited only by the maximum chunk size. 621 */ 622 png_alloc_size_t limit = PNG_SIZE_MAX; 623 624 # ifdef PNG_SET_USER_LIMITS_SUPPORTED 625 if (png_ptr->user_chunk_malloc_max > 0 && 626 png_ptr->user_chunk_malloc_max < limit) 627 limit = png_ptr->user_chunk_malloc_max; 628 # elif PNG_USER_CHUNK_MALLOC_MAX > 0 629 if (PNG_USER_CHUNK_MALLOC_MAX < limit) 630 limit = PNG_USER_CHUNK_MALLOC_MAX; 631 # endif 632 633 if (limit >= prefix_size + (terminate != 0)) 634 { 635 int ret; 636 637 limit -= prefix_size + (terminate != 0); 638 639 if (limit < *newlength) 640 *newlength = limit; 641 642 /* Now try to claim the stream. */ 643 ret = png_inflate_claim(png_ptr, png_ptr->chunk_name); 644 645 if (ret == Z_OK) 646 { 647 png_uint_32 lzsize = chunklength - prefix_size; 648 649 ret = png_inflate(png_ptr, png_ptr->chunk_name, 1/*finish*/, 650 /* input: */ png_ptr->read_buffer + prefix_size, &lzsize, 651 /* output: */ NULL, newlength); 652 653 if (ret == Z_STREAM_END) 654 { 655 /* Use 'inflateReset' here, not 'inflateReset2' because this 656 * preserves the previously decided window size (otherwise it would 657 * be necessary to store the previous window size.) In practice 658 * this doesn't matter anyway, because png_inflate will call inflate 659 * with Z_FINISH in almost all cases, so the window will not be 660 * maintained. 661 */ 662 if (inflateReset(&png_ptr->zstream) == Z_OK) 663 { 664 /* Because of the limit checks above we know that the new, 665 * expanded, size will fit in a size_t (let alone an 666 * png_alloc_size_t). Use png_malloc_base here to avoid an 667 * extra OOM message. 668 */ 669 png_alloc_size_t new_size = *newlength; 670 png_alloc_size_t buffer_size = prefix_size + new_size + 671 (terminate != 0); 672 png_bytep text = png_voidcast(png_bytep, png_malloc_base(png_ptr, 673 buffer_size)); 674 675 if (text != NULL) 676 { 677 memset(text, 0, buffer_size); 678 679 ret = png_inflate(png_ptr, png_ptr->chunk_name, 1/*finish*/, 680 png_ptr->read_buffer + prefix_size, &lzsize, 681 text + prefix_size, newlength); 682 683 if (ret == Z_STREAM_END) 684 { 685 if (new_size == *newlength) 686 { 687 if (terminate != 0) 688 text[prefix_size + *newlength] = 0; 689 690 if (prefix_size > 0) 691 memcpy(text, png_ptr->read_buffer, prefix_size); 692 693 { 694 png_bytep old_ptr = png_ptr->read_buffer; 695 696 png_ptr->read_buffer = text; 697 png_ptr->read_buffer_size = buffer_size; 698 text = old_ptr; /* freed below */ 699 } 700 } 701 702 else 703 { 704 /* The size changed on the second read, there can be no 705 * guarantee that anything is correct at this point. 706 * The 'msg' pointer has been set to "unexpected end of 707 * LZ stream", which is fine, but return an error code 708 * that the caller won't accept. 709 */ 710 ret = PNG_UNEXPECTED_ZLIB_RETURN; 711 } 712 } 713 714 else if (ret == Z_OK) 715 ret = PNG_UNEXPECTED_ZLIB_RETURN; /* for safety */ 716 717 /* Free the text pointer (this is the old read_buffer on 718 * success) 719 */ 720 png_free(png_ptr, text); 721 722 /* This really is very benign, but it's still an error because 723 * the extra space may otherwise be used as a Trojan Horse. 724 */ 725 if (ret == Z_STREAM_END && 726 chunklength - prefix_size != lzsize) 727 png_chunk_benign_error(png_ptr, "extra compressed data"); 728 } 729 730 else 731 { 732 /* Out of memory allocating the buffer */ 733 ret = Z_MEM_ERROR; 734 png_zstream_error(png_ptr, Z_MEM_ERROR); 735 } 736 } 737 738 else 739 { 740 /* inflateReset failed, store the error message */ 741 png_zstream_error(png_ptr, ret); 742 ret = PNG_UNEXPECTED_ZLIB_RETURN; 743 } 744 } 745 746 else if (ret == Z_OK) 747 ret = PNG_UNEXPECTED_ZLIB_RETURN; 748 749 /* Release the claimed stream */ 750 png_ptr->zowner = 0; 751 } 752 753 else /* the claim failed */ if (ret == Z_STREAM_END) /* impossible! */ 754 ret = PNG_UNEXPECTED_ZLIB_RETURN; 755 756 return ret; 757 } 758 759 else 760 { 761 /* Application/configuration limits exceeded */ 762 png_zstream_error(png_ptr, Z_MEM_ERROR); 763 return Z_MEM_ERROR; 764 } 765 } 766 #endif /* READ_zTXt || READ_iTXt */ 767 #endif /* READ_COMPRESSED_TEXT */ 768 769 #ifdef PNG_READ_iCCP_SUPPORTED 770 /* Perform a partial read and decompress, producing 'avail_out' bytes and 771 * reading from the current chunk as required. 772 */ 773 static int 774 png_inflate_read(png_structrp png_ptr, png_bytep read_buffer, uInt read_size, 775 png_uint_32p chunk_bytes, png_bytep next_out, png_alloc_size_t *out_size, 776 int finish) 777 { 778 if (png_ptr->zowner == png_ptr->chunk_name) 779 { 780 int ret; 781 782 /* next_in and avail_in must have been initialized by the caller. */ 783 png_ptr->zstream.next_out = next_out; 784 png_ptr->zstream.avail_out = 0; /* set in the loop */ 785 786 do 787 { 788 if (png_ptr->zstream.avail_in == 0) 789 { 790 if (read_size > *chunk_bytes) 791 read_size = (uInt)*chunk_bytes; 792 *chunk_bytes -= read_size; 793 794 if (read_size > 0) 795 png_crc_read(png_ptr, read_buffer, read_size); 796 797 png_ptr->zstream.next_in = read_buffer; 798 png_ptr->zstream.avail_in = read_size; 799 } 800 801 if (png_ptr->zstream.avail_out == 0) 802 { 803 uInt avail = ZLIB_IO_MAX; 804 if (avail > *out_size) 805 avail = (uInt)*out_size; 806 *out_size -= avail; 807 808 png_ptr->zstream.avail_out = avail; 809 } 810 811 /* Use Z_SYNC_FLUSH when there is no more chunk data to ensure that all 812 * the available output is produced; this allows reading of truncated 813 * streams. 814 */ 815 ret = PNG_INFLATE(png_ptr, *chunk_bytes > 0 ? 816 Z_NO_FLUSH : (finish ? Z_FINISH : Z_SYNC_FLUSH)); 817 } 818 while (ret == Z_OK && (*out_size > 0 || png_ptr->zstream.avail_out > 0)); 819 820 *out_size += png_ptr->zstream.avail_out; 821 png_ptr->zstream.avail_out = 0; /* Should not be required, but is safe */ 822 823 /* Ensure the error message pointer is always set: */ 824 png_zstream_error(png_ptr, ret); 825 return ret; 826 } 827 828 else 829 { 830 png_ptr->zstream.msg = PNGZ_MSG_CAST("zstream unclaimed"); 831 return Z_STREAM_ERROR; 832 } 833 } 834 #endif /* READ_iCCP */ 835 836 /* Read and check the IDHR chunk */ 837 838 void /* PRIVATE */ 839 png_handle_IHDR(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 840 { 841 png_byte buf[13]; 842 png_uint_32 width, height; 843 int bit_depth, color_type, compression_type, filter_type; 844 int interlace_type; 845 846 png_debug(1, "in png_handle_IHDR"); 847 848 if ((png_ptr->mode & PNG_HAVE_IHDR) != 0) 849 png_chunk_error(png_ptr, "out of place"); 850 851 /* Check the length */ 852 if (length != 13) 853 png_chunk_error(png_ptr, "invalid"); 854 855 png_ptr->mode |= PNG_HAVE_IHDR; 856 857 png_crc_read(png_ptr, buf, 13); 858 png_crc_finish(png_ptr, 0); 859 860 width = png_get_uint_31(png_ptr, buf); 861 height = png_get_uint_31(png_ptr, buf + 4); 862 bit_depth = buf[8]; 863 color_type = buf[9]; 864 compression_type = buf[10]; 865 filter_type = buf[11]; 866 interlace_type = buf[12]; 867 868 /* Set internal variables */ 869 png_ptr->width = width; 870 png_ptr->height = height; 871 png_ptr->bit_depth = (png_byte)bit_depth; 872 png_ptr->interlaced = (png_byte)interlace_type; 873 png_ptr->color_type = (png_byte)color_type; 874 #ifdef PNG_MNG_FEATURES_SUPPORTED 875 png_ptr->filter_type = (png_byte)filter_type; 876 #endif 877 png_ptr->compression_type = (png_byte)compression_type; 878 879 /* Find number of channels */ 880 switch (png_ptr->color_type) 881 { 882 default: /* invalid, png_set_IHDR calls png_error */ 883 case PNG_COLOR_TYPE_GRAY: 884 case PNG_COLOR_TYPE_PALETTE: 885 png_ptr->channels = 1; 886 break; 887 888 case PNG_COLOR_TYPE_RGB: 889 png_ptr->channels = 3; 890 break; 891 892 case PNG_COLOR_TYPE_GRAY_ALPHA: 893 png_ptr->channels = 2; 894 break; 895 896 case PNG_COLOR_TYPE_RGB_ALPHA: 897 png_ptr->channels = 4; 898 break; 899 } 900 901 /* Set up other useful info */ 902 png_ptr->pixel_depth = (png_byte)(png_ptr->bit_depth * png_ptr->channels); 903 png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->width); 904 png_debug1(3, "bit_depth = %d", png_ptr->bit_depth); 905 png_debug1(3, "channels = %d", png_ptr->channels); 906 png_debug1(3, "rowbytes = %lu", (unsigned long)png_ptr->rowbytes); 907 png_set_IHDR(png_ptr, info_ptr, width, height, bit_depth, 908 color_type, interlace_type, compression_type, filter_type); 909 } 910 911 /* Read and check the palette */ 912 void /* PRIVATE */ 913 png_handle_PLTE(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 914 { 915 png_color palette[PNG_MAX_PALETTE_LENGTH]; 916 int max_palette_length, num, i; 917 #ifdef PNG_POINTER_INDEXING_SUPPORTED 918 png_colorp pal_ptr; 919 #endif 920 921 png_debug(1, "in png_handle_PLTE"); 922 923 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 924 png_chunk_error(png_ptr, "missing IHDR"); 925 926 /* Moved to before the 'after IDAT' check below because otherwise duplicate 927 * PLTE chunks are potentially ignored (the spec says there shall not be more 928 * than one PLTE, the error is not treated as benign, so this check trumps 929 * the requirement that PLTE appears before IDAT.) 930 */ 931 else if ((png_ptr->mode & PNG_HAVE_PLTE) != 0) 932 png_chunk_error(png_ptr, "duplicate"); 933 934 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) 935 { 936 /* This is benign because the non-benign error happened before, when an 937 * IDAT was encountered in a color-mapped image with no PLTE. 938 */ 939 png_crc_finish(png_ptr, length); 940 png_chunk_benign_error(png_ptr, "out of place"); 941 return; 942 } 943 944 png_ptr->mode |= PNG_HAVE_PLTE; 945 946 if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0) 947 { 948 png_crc_finish(png_ptr, length); 949 png_chunk_benign_error(png_ptr, "ignored in grayscale PNG"); 950 return; 951 } 952 953 #ifndef PNG_READ_OPT_PLTE_SUPPORTED 954 if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE) 955 { 956 png_crc_finish(png_ptr, length); 957 return; 958 } 959 #endif 960 961 if (length > 3*PNG_MAX_PALETTE_LENGTH || length % 3) 962 { 963 png_crc_finish(png_ptr, length); 964 965 if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE) 966 png_chunk_benign_error(png_ptr, "invalid"); 967 968 else 969 png_chunk_error(png_ptr, "invalid"); 970 971 return; 972 } 973 974 /* The cast is safe because 'length' is less than 3*PNG_MAX_PALETTE_LENGTH */ 975 num = (int)length / 3; 976 977 /* If the palette has 256 or fewer entries but is too large for the bit 978 * depth, we don't issue an error, to preserve the behavior of previous 979 * libpng versions. We silently truncate the unused extra palette entries 980 * here. 981 */ 982 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) 983 max_palette_length = (1 << png_ptr->bit_depth); 984 else 985 max_palette_length = PNG_MAX_PALETTE_LENGTH; 986 987 if (num > max_palette_length) 988 num = max_palette_length; 989 990 #ifdef PNG_POINTER_INDEXING_SUPPORTED 991 for (i = 0, pal_ptr = palette; i < num; i++, pal_ptr++) 992 { 993 png_byte buf[3]; 994 995 png_crc_read(png_ptr, buf, 3); 996 pal_ptr->red = buf[0]; 997 pal_ptr->green = buf[1]; 998 pal_ptr->blue = buf[2]; 999 } 1000 #else 1001 for (i = 0; i < num; i++) 1002 { 1003 png_byte buf[3]; 1004 1005 png_crc_read(png_ptr, buf, 3); 1006 /* Don't depend upon png_color being any order */ 1007 palette[i].red = buf[0]; 1008 palette[i].green = buf[1]; 1009 palette[i].blue = buf[2]; 1010 } 1011 #endif 1012 1013 /* If we actually need the PLTE chunk (ie for a paletted image), we do 1014 * whatever the normal CRC configuration tells us. However, if we 1015 * have an RGB image, the PLTE can be considered ancillary, so 1016 * we will act as though it is. 1017 */ 1018 #ifndef PNG_READ_OPT_PLTE_SUPPORTED 1019 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) 1020 #endif 1021 { 1022 png_crc_finish(png_ptr, (png_uint_32) (length - (unsigned int)num * 3)); 1023 } 1024 1025 #ifndef PNG_READ_OPT_PLTE_SUPPORTED 1026 else if (png_crc_error(png_ptr) != 0) /* Only if we have a CRC error */ 1027 { 1028 /* If we don't want to use the data from an ancillary chunk, 1029 * we have two options: an error abort, or a warning and we 1030 * ignore the data in this chunk (which should be OK, since 1031 * it's considered ancillary for a RGB or RGBA image). 1032 * 1033 * IMPLEMENTATION NOTE: this is only here because png_crc_finish uses the 1034 * chunk type to determine whether to check the ancillary or the critical 1035 * flags. 1036 */ 1037 if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_USE) == 0) 1038 { 1039 if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) != 0) 1040 return; 1041 1042 else 1043 png_chunk_error(png_ptr, "CRC error"); 1044 } 1045 1046 /* Otherwise, we (optionally) emit a warning and use the chunk. */ 1047 else if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) == 0) 1048 png_chunk_warning(png_ptr, "CRC error"); 1049 } 1050 #endif 1051 1052 /* TODO: png_set_PLTE has the side effect of setting png_ptr->palette to its 1053 * own copy of the palette. This has the side effect that when png_start_row 1054 * is called (this happens after any call to png_read_update_info) the 1055 * info_ptr palette gets changed. This is extremely unexpected and 1056 * confusing. 1057 * 1058 * Fix this by not sharing the palette in this way. 1059 */ 1060 png_set_PLTE(png_ptr, info_ptr, palette, num); 1061 1062 /* The three chunks, bKGD, hIST and tRNS *must* appear after PLTE and before 1063 * IDAT. Prior to 1.6.0 this was not checked; instead the code merely 1064 * checked the apparent validity of a tRNS chunk inserted before PLTE on a 1065 * palette PNG. 1.6.0 attempts to rigorously follow the standard and 1066 * therefore does a benign error if the erroneous condition is detected *and* 1067 * cancels the tRNS if the benign error returns. The alternative is to 1068 * amend the standard since it would be rather hypocritical of the standards 1069 * maintainers to ignore it. 1070 */ 1071 #ifdef PNG_READ_tRNS_SUPPORTED 1072 if (png_ptr->num_trans > 0 || 1073 (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS) != 0)) 1074 { 1075 /* Cancel this because otherwise it would be used if the transforms 1076 * require it. Don't cancel the 'valid' flag because this would prevent 1077 * detection of duplicate chunks. 1078 */ 1079 png_ptr->num_trans = 0; 1080 1081 if (info_ptr != NULL) 1082 info_ptr->num_trans = 0; 1083 1084 png_chunk_benign_error(png_ptr, "tRNS must be after"); 1085 } 1086 #endif 1087 1088 #ifdef PNG_READ_hIST_SUPPORTED 1089 if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST) != 0) 1090 png_chunk_benign_error(png_ptr, "hIST must be after"); 1091 #endif 1092 1093 #ifdef PNG_READ_bKGD_SUPPORTED 1094 if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD) != 0) 1095 png_chunk_benign_error(png_ptr, "bKGD must be after"); 1096 #endif 1097 } 1098 1099 void /* PRIVATE */ 1100 png_handle_IEND(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 1101 { 1102 png_debug(1, "in png_handle_IEND"); 1103 1104 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0 || 1105 (png_ptr->mode & PNG_HAVE_IDAT) == 0) 1106 png_chunk_error(png_ptr, "out of place"); 1107 1108 png_ptr->mode |= (PNG_AFTER_IDAT | PNG_HAVE_IEND); 1109 1110 png_crc_finish(png_ptr, length); 1111 1112 if (length != 0) 1113 png_chunk_benign_error(png_ptr, "invalid"); 1114 1115 PNG_UNUSED(info_ptr) 1116 } 1117 1118 #ifdef PNG_READ_gAMA_SUPPORTED 1119 void /* PRIVATE */ 1120 png_handle_gAMA(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 1121 { 1122 png_fixed_point igamma; 1123 png_byte buf[4]; 1124 1125 png_debug(1, "in png_handle_gAMA"); 1126 1127 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 1128 png_chunk_error(png_ptr, "missing IHDR"); 1129 1130 else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0) 1131 { 1132 png_crc_finish(png_ptr, length); 1133 png_chunk_benign_error(png_ptr, "out of place"); 1134 return; 1135 } 1136 1137 if (length != 4) 1138 { 1139 png_crc_finish(png_ptr, length); 1140 png_chunk_benign_error(png_ptr, "invalid"); 1141 return; 1142 } 1143 1144 png_crc_read(png_ptr, buf, 4); 1145 1146 if (png_crc_finish(png_ptr, 0) != 0) 1147 return; 1148 1149 igamma = png_get_fixed_point(NULL, buf); 1150 1151 png_colorspace_set_gamma(png_ptr, &png_ptr->colorspace, igamma); 1152 png_colorspace_sync(png_ptr, info_ptr); 1153 } 1154 #endif 1155 1156 #ifdef PNG_READ_sBIT_SUPPORTED 1157 void /* PRIVATE */ 1158 png_handle_sBIT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 1159 { 1160 unsigned int truelen, i; 1161 png_byte sample_depth; 1162 png_byte buf[4]; 1163 1164 png_debug(1, "in png_handle_sBIT"); 1165 1166 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 1167 png_chunk_error(png_ptr, "missing IHDR"); 1168 1169 else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0) 1170 { 1171 png_crc_finish(png_ptr, length); 1172 png_chunk_benign_error(png_ptr, "out of place"); 1173 return; 1174 } 1175 1176 if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sBIT) != 0) 1177 { 1178 png_crc_finish(png_ptr, length); 1179 png_chunk_benign_error(png_ptr, "duplicate"); 1180 return; 1181 } 1182 1183 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) 1184 { 1185 truelen = 3; 1186 sample_depth = 8; 1187 } 1188 1189 else 1190 { 1191 truelen = png_ptr->channels; 1192 sample_depth = png_ptr->bit_depth; 1193 } 1194 1195 if (length != truelen || length > 4) 1196 { 1197 png_chunk_benign_error(png_ptr, "invalid"); 1198 png_crc_finish(png_ptr, length); 1199 return; 1200 } 1201 1202 buf[0] = buf[1] = buf[2] = buf[3] = sample_depth; 1203 png_crc_read(png_ptr, buf, truelen); 1204 1205 if (png_crc_finish(png_ptr, 0) != 0) 1206 return; 1207 1208 for (i=0; i<truelen; ++i) 1209 { 1210 if (buf[i] == 0 || buf[i] > sample_depth) 1211 { 1212 png_chunk_benign_error(png_ptr, "invalid"); 1213 return; 1214 } 1215 } 1216 1217 if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0) 1218 { 1219 png_ptr->sig_bit.red = buf[0]; 1220 png_ptr->sig_bit.green = buf[1]; 1221 png_ptr->sig_bit.blue = buf[2]; 1222 png_ptr->sig_bit.alpha = buf[3]; 1223 } 1224 1225 else 1226 { 1227 png_ptr->sig_bit.gray = buf[0]; 1228 png_ptr->sig_bit.red = buf[0]; 1229 png_ptr->sig_bit.green = buf[0]; 1230 png_ptr->sig_bit.blue = buf[0]; 1231 png_ptr->sig_bit.alpha = buf[1]; 1232 } 1233 1234 png_set_sBIT(png_ptr, info_ptr, &(png_ptr->sig_bit)); 1235 } 1236 #endif 1237 1238 #ifdef PNG_READ_cHRM_SUPPORTED 1239 void /* PRIVATE */ 1240 png_handle_cHRM(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 1241 { 1242 png_byte buf[32]; 1243 png_xy xy; 1244 1245 png_debug(1, "in png_handle_cHRM"); 1246 1247 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 1248 png_chunk_error(png_ptr, "missing IHDR"); 1249 1250 else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0) 1251 { 1252 png_crc_finish(png_ptr, length); 1253 png_chunk_benign_error(png_ptr, "out of place"); 1254 return; 1255 } 1256 1257 if (length != 32) 1258 { 1259 png_crc_finish(png_ptr, length); 1260 png_chunk_benign_error(png_ptr, "invalid"); 1261 return; 1262 } 1263 1264 png_crc_read(png_ptr, buf, 32); 1265 1266 if (png_crc_finish(png_ptr, 0) != 0) 1267 return; 1268 1269 xy.whitex = png_get_fixed_point(NULL, buf); 1270 xy.whitey = png_get_fixed_point(NULL, buf + 4); 1271 xy.redx = png_get_fixed_point(NULL, buf + 8); 1272 xy.redy = png_get_fixed_point(NULL, buf + 12); 1273 xy.greenx = png_get_fixed_point(NULL, buf + 16); 1274 xy.greeny = png_get_fixed_point(NULL, buf + 20); 1275 xy.bluex = png_get_fixed_point(NULL, buf + 24); 1276 xy.bluey = png_get_fixed_point(NULL, buf + 28); 1277 1278 if (xy.whitex == PNG_FIXED_ERROR || 1279 xy.whitey == PNG_FIXED_ERROR || 1280 xy.redx == PNG_FIXED_ERROR || 1281 xy.redy == PNG_FIXED_ERROR || 1282 xy.greenx == PNG_FIXED_ERROR || 1283 xy.greeny == PNG_FIXED_ERROR || 1284 xy.bluex == PNG_FIXED_ERROR || 1285 xy.bluey == PNG_FIXED_ERROR) 1286 { 1287 png_chunk_benign_error(png_ptr, "invalid values"); 1288 return; 1289 } 1290 1291 /* If a colorspace error has already been output skip this chunk */ 1292 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0) 1293 return; 1294 1295 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_FROM_cHRM) != 0) 1296 { 1297 png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID; 1298 png_colorspace_sync(png_ptr, info_ptr); 1299 png_chunk_benign_error(png_ptr, "duplicate"); 1300 return; 1301 } 1302 1303 png_ptr->colorspace.flags |= PNG_COLORSPACE_FROM_cHRM; 1304 (void)png_colorspace_set_chromaticities(png_ptr, &png_ptr->colorspace, &xy, 1305 1/*prefer cHRM values*/); 1306 png_colorspace_sync(png_ptr, info_ptr); 1307 } 1308 #endif 1309 1310 #ifdef PNG_READ_sRGB_SUPPORTED 1311 void /* PRIVATE */ 1312 png_handle_sRGB(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 1313 { 1314 png_byte intent; 1315 1316 png_debug(1, "in png_handle_sRGB"); 1317 1318 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 1319 png_chunk_error(png_ptr, "missing IHDR"); 1320 1321 else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0) 1322 { 1323 png_crc_finish(png_ptr, length); 1324 png_chunk_benign_error(png_ptr, "out of place"); 1325 return; 1326 } 1327 1328 if (length != 1) 1329 { 1330 png_crc_finish(png_ptr, length); 1331 png_chunk_benign_error(png_ptr, "invalid"); 1332 return; 1333 } 1334 1335 png_crc_read(png_ptr, &intent, 1); 1336 1337 if (png_crc_finish(png_ptr, 0) != 0) 1338 return; 1339 1340 /* If a colorspace error has already been output skip this chunk */ 1341 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0) 1342 return; 1343 1344 /* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect 1345 * this. 1346 */ 1347 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_INTENT) != 0) 1348 { 1349 png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID; 1350 png_colorspace_sync(png_ptr, info_ptr); 1351 png_chunk_benign_error(png_ptr, "too many profiles"); 1352 return; 1353 } 1354 1355 (void)png_colorspace_set_sRGB(png_ptr, &png_ptr->colorspace, intent); 1356 png_colorspace_sync(png_ptr, info_ptr); 1357 } 1358 #endif /* READ_sRGB */ 1359 1360 #ifdef PNG_READ_iCCP_SUPPORTED 1361 void /* PRIVATE */ 1362 png_handle_iCCP(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 1363 /* Note: this does not properly handle profiles that are > 64K under DOS */ 1364 { 1365 png_const_charp errmsg = NULL; /* error message output, or no error */ 1366 int finished = 0; /* crc checked */ 1367 1368 png_debug(1, "in png_handle_iCCP"); 1369 1370 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 1371 png_chunk_error(png_ptr, "missing IHDR"); 1372 1373 else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0) 1374 { 1375 png_crc_finish(png_ptr, length); 1376 png_chunk_benign_error(png_ptr, "out of place"); 1377 return; 1378 } 1379 1380 /* Consistent with all the above colorspace handling an obviously *invalid* 1381 * chunk is just ignored, so does not invalidate the color space. An 1382 * alternative is to set the 'invalid' flags at the start of this routine 1383 * and only clear them in they were not set before and all the tests pass. 1384 */ 1385 1386 /* The keyword must be at least one character and there is a 1387 * terminator (0) byte and the compression method byte, and the 1388 * 'zlib' datastream is at least 11 bytes. 1389 */ 1390 if (length < 14) 1391 { 1392 png_crc_finish(png_ptr, length); 1393 png_chunk_benign_error(png_ptr, "too short"); 1394 return; 1395 } 1396 1397 /* If a colorspace error has already been output skip this chunk */ 1398 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0) 1399 { 1400 png_crc_finish(png_ptr, length); 1401 return; 1402 } 1403 1404 /* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect 1405 * this. 1406 */ 1407 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_INTENT) == 0) 1408 { 1409 uInt read_length, keyword_length; 1410 char keyword[81]; 1411 1412 /* Find the keyword; the keyword plus separator and compression method 1413 * bytes can be at most 81 characters long. 1414 */ 1415 read_length = 81; /* maximum */ 1416 if (read_length > length) 1417 read_length = (uInt)length; 1418 1419 png_crc_read(png_ptr, (png_bytep)keyword, read_length); 1420 length -= read_length; 1421 1422 /* The minimum 'zlib' stream is assumed to be just the 2 byte header, 1423 * 5 bytes minimum 'deflate' stream, and the 4 byte checksum. 1424 */ 1425 if (length < 11) 1426 { 1427 png_crc_finish(png_ptr, length); 1428 png_chunk_benign_error(png_ptr, "too short"); 1429 return; 1430 } 1431 1432 keyword_length = 0; 1433 while (keyword_length < 80 && keyword_length < read_length && 1434 keyword[keyword_length] != 0) 1435 ++keyword_length; 1436 1437 /* TODO: make the keyword checking common */ 1438 if (keyword_length >= 1 && keyword_length <= 79) 1439 { 1440 /* We only understand '0' compression - deflate - so if we get a 1441 * different value we can't safely decode the chunk. 1442 */ 1443 if (keyword_length+1 < read_length && 1444 keyword[keyword_length+1] == PNG_COMPRESSION_TYPE_BASE) 1445 { 1446 read_length -= keyword_length+2; 1447 1448 if (png_inflate_claim(png_ptr, png_iCCP) == Z_OK) 1449 { 1450 Byte profile_header[132]={0}; 1451 Byte local_buffer[PNG_INFLATE_BUF_SIZE]; 1452 png_alloc_size_t size = (sizeof profile_header); 1453 1454 png_ptr->zstream.next_in = (Bytef*)keyword + (keyword_length+2); 1455 png_ptr->zstream.avail_in = read_length; 1456 (void)png_inflate_read(png_ptr, local_buffer, 1457 (sizeof local_buffer), &length, profile_header, &size, 1458 0/*finish: don't, because the output is too small*/); 1459 1460 if (size == 0) 1461 { 1462 /* We have the ICC profile header; do the basic header checks. 1463 */ 1464 const png_uint_32 profile_length = 1465 png_get_uint_32(profile_header); 1466 1467 if (png_icc_check_length(png_ptr, &png_ptr->colorspace, 1468 keyword, profile_length) != 0) 1469 { 1470 /* The length is apparently ok, so we can check the 132 1471 * byte header. 1472 */ 1473 if (png_icc_check_header(png_ptr, &png_ptr->colorspace, 1474 keyword, profile_length, profile_header, 1475 png_ptr->color_type) != 0) 1476 { 1477 /* Now read the tag table; a variable size buffer is 1478 * needed at this point, allocate one for the whole 1479 * profile. The header check has already validated 1480 * that none of this stuff will overflow. 1481 */ 1482 const png_uint_32 tag_count = png_get_uint_32( 1483 profile_header+128); 1484 png_bytep profile = png_read_buffer(png_ptr, 1485 profile_length, 2/*silent*/); 1486 1487 if (profile != NULL) 1488 { 1489 memcpy(profile, profile_header, 1490 (sizeof profile_header)); 1491 1492 size = 12 * tag_count; 1493 1494 (void)png_inflate_read(png_ptr, local_buffer, 1495 (sizeof local_buffer), &length, 1496 profile + (sizeof profile_header), &size, 0); 1497 1498 /* Still expect a buffer error because we expect 1499 * there to be some tag data! 1500 */ 1501 if (size == 0) 1502 { 1503 if (png_icc_check_tag_table(png_ptr, 1504 &png_ptr->colorspace, keyword, profile_length, 1505 profile) != 0) 1506 { 1507 /* The profile has been validated for basic 1508 * security issues, so read the whole thing in. 1509 */ 1510 size = profile_length - (sizeof profile_header) 1511 - 12 * tag_count; 1512 1513 (void)png_inflate_read(png_ptr, local_buffer, 1514 (sizeof local_buffer), &length, 1515 profile + (sizeof profile_header) + 1516 12 * tag_count, &size, 1/*finish*/); 1517 1518 if (length > 0 && !(png_ptr->flags & 1519 PNG_FLAG_BENIGN_ERRORS_WARN)) 1520 errmsg = "extra compressed data"; 1521 1522 /* But otherwise allow extra data: */ 1523 else if (size == 0) 1524 { 1525 if (length > 0) 1526 { 1527 /* This can be handled completely, so 1528 * keep going. 1529 */ 1530 png_chunk_warning(png_ptr, 1531 "extra compressed data"); 1532 } 1533 1534 png_crc_finish(png_ptr, length); 1535 finished = 1; 1536 1537 # if defined(PNG_sRGB_SUPPORTED) && PNG_sRGB_PROFILE_CHECKS >= 0 1538 /* Check for a match against sRGB */ 1539 png_icc_set_sRGB(png_ptr, 1540 &png_ptr->colorspace, profile, 1541 png_ptr->zstream.adler); 1542 # endif 1543 1544 /* Steal the profile for info_ptr. */ 1545 if (info_ptr != NULL) 1546 { 1547 png_free_data(png_ptr, info_ptr, 1548 PNG_FREE_ICCP, 0); 1549 1550 info_ptr->iccp_name = png_voidcast(char*, 1551 png_malloc_base(png_ptr, 1552 keyword_length+1)); 1553 if (info_ptr->iccp_name != NULL) 1554 { 1555 memcpy(info_ptr->iccp_name, keyword, 1556 keyword_length+1); 1557 info_ptr->iccp_proflen = 1558 profile_length; 1559 info_ptr->iccp_profile = profile; 1560 png_ptr->read_buffer = NULL; /*steal*/ 1561 info_ptr->free_me |= PNG_FREE_ICCP; 1562 info_ptr->valid |= PNG_INFO_iCCP; 1563 } 1564 1565 else 1566 { 1567 png_ptr->colorspace.flags |= 1568 PNG_COLORSPACE_INVALID; 1569 errmsg = "out of memory"; 1570 } 1571 } 1572 1573 /* else the profile remains in the read 1574 * buffer which gets reused for subsequent 1575 * chunks. 1576 */ 1577 1578 if (info_ptr != NULL) 1579 png_colorspace_sync(png_ptr, info_ptr); 1580 1581 if (errmsg == NULL) 1582 { 1583 png_ptr->zowner = 0; 1584 return; 1585 } 1586 } 1587 if (errmsg == NULL) 1588 errmsg = png_ptr->zstream.msg; 1589 } 1590 /* else png_icc_check_tag_table output an error */ 1591 } 1592 else /* profile truncated */ 1593 errmsg = png_ptr->zstream.msg; 1594 } 1595 1596 else 1597 errmsg = "out of memory"; 1598 } 1599 1600 /* else png_icc_check_header output an error */ 1601 } 1602 1603 /* else png_icc_check_length output an error */ 1604 } 1605 1606 else /* profile truncated */ 1607 errmsg = png_ptr->zstream.msg; 1608 1609 /* Release the stream */ 1610 png_ptr->zowner = 0; 1611 } 1612 1613 else /* png_inflate_claim failed */ 1614 errmsg = png_ptr->zstream.msg; 1615 } 1616 1617 else 1618 errmsg = "bad compression method"; /* or missing */ 1619 } 1620 1621 else 1622 errmsg = "bad keyword"; 1623 } 1624 1625 else 1626 errmsg = "too many profiles"; 1627 1628 /* Failure: the reason is in 'errmsg' */ 1629 if (finished == 0) 1630 png_crc_finish(png_ptr, length); 1631 1632 png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID; 1633 png_colorspace_sync(png_ptr, info_ptr); 1634 if (errmsg != NULL) /* else already output */ 1635 png_chunk_benign_error(png_ptr, errmsg); 1636 } 1637 #endif /* READ_iCCP */ 1638 1639 #ifdef PNG_READ_sPLT_SUPPORTED 1640 void /* PRIVATE */ 1641 png_handle_sPLT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 1642 /* Note: this does not properly handle chunks that are > 64K under DOS */ 1643 { 1644 png_bytep entry_start, buffer; 1645 png_sPLT_t new_palette; 1646 png_sPLT_entryp pp; 1647 png_uint_32 data_length; 1648 int entry_size, i; 1649 png_uint_32 skip = 0; 1650 png_uint_32 dl; 1651 png_size_t max_dl; 1652 1653 png_debug(1, "in png_handle_sPLT"); 1654 1655 #ifdef PNG_USER_LIMITS_SUPPORTED 1656 if (png_ptr->user_chunk_cache_max != 0) 1657 { 1658 if (png_ptr->user_chunk_cache_max == 1) 1659 { 1660 png_crc_finish(png_ptr, length); 1661 return; 1662 } 1663 1664 if (--png_ptr->user_chunk_cache_max == 1) 1665 { 1666 png_warning(png_ptr, "No space in chunk cache for sPLT"); 1667 png_crc_finish(png_ptr, length); 1668 return; 1669 } 1670 } 1671 #endif 1672 1673 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 1674 png_chunk_error(png_ptr, "missing IHDR"); 1675 1676 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) 1677 { 1678 png_crc_finish(png_ptr, length); 1679 png_chunk_benign_error(png_ptr, "out of place"); 1680 return; 1681 } 1682 1683 #ifdef PNG_MAX_MALLOC_64K 1684 if (length > 65535U) 1685 { 1686 png_crc_finish(png_ptr, length); 1687 png_chunk_benign_error(png_ptr, "too large to fit in memory"); 1688 return; 1689 } 1690 #endif 1691 1692 buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/); 1693 if (buffer == NULL) 1694 { 1695 png_crc_finish(png_ptr, length); 1696 png_chunk_benign_error(png_ptr, "out of memory"); 1697 return; 1698 } 1699 1700 1701 /* WARNING: this may break if size_t is less than 32 bits; it is assumed 1702 * that the PNG_MAX_MALLOC_64K test is enabled in this case, but this is a 1703 * potential breakage point if the types in pngconf.h aren't exactly right. 1704 */ 1705 png_crc_read(png_ptr, buffer, length); 1706 1707 if (png_crc_finish(png_ptr, skip) != 0) 1708 return; 1709 1710 buffer[length] = 0; 1711 1712 for (entry_start = buffer; *entry_start; entry_start++) 1713 /* Empty loop to find end of name */ ; 1714 1715 ++entry_start; 1716 1717 /* A sample depth should follow the separator, and we should be on it */ 1718 if (length < 2U || entry_start > buffer + (length - 2U)) 1719 { 1720 png_warning(png_ptr, "malformed sPLT chunk"); 1721 return; 1722 } 1723 1724 new_palette.depth = *entry_start++; 1725 entry_size = (new_palette.depth == 8 ? 6 : 10); 1726 /* This must fit in a png_uint_32 because it is derived from the original 1727 * chunk data length. 1728 */ 1729 data_length = length - (png_uint_32)(entry_start - buffer); 1730 1731 /* Integrity-check the data length */ 1732 if ((data_length % (unsigned int)entry_size) != 0) 1733 { 1734 png_warning(png_ptr, "sPLT chunk has bad length"); 1735 return; 1736 } 1737 1738 dl = (png_uint_32)(data_length / (unsigned int)entry_size); 1739 max_dl = PNG_SIZE_MAX / (sizeof (png_sPLT_entry)); 1740 1741 if (dl > max_dl) 1742 { 1743 png_warning(png_ptr, "sPLT chunk too long"); 1744 return; 1745 } 1746 1747 new_palette.nentries = (png_int_32)(data_length / (unsigned int)entry_size); 1748 1749 new_palette.entries = (png_sPLT_entryp)png_malloc_warn(png_ptr, 1750 (png_alloc_size_t) new_palette.nentries * (sizeof (png_sPLT_entry))); 1751 1752 if (new_palette.entries == NULL) 1753 { 1754 png_warning(png_ptr, "sPLT chunk requires too much memory"); 1755 return; 1756 } 1757 1758 #ifdef PNG_POINTER_INDEXING_SUPPORTED 1759 for (i = 0; i < new_palette.nentries; i++) 1760 { 1761 pp = new_palette.entries + i; 1762 1763 if (new_palette.depth == 8) 1764 { 1765 pp->red = *entry_start++; 1766 pp->green = *entry_start++; 1767 pp->blue = *entry_start++; 1768 pp->alpha = *entry_start++; 1769 } 1770 1771 else 1772 { 1773 pp->red = png_get_uint_16(entry_start); entry_start += 2; 1774 pp->green = png_get_uint_16(entry_start); entry_start += 2; 1775 pp->blue = png_get_uint_16(entry_start); entry_start += 2; 1776 pp->alpha = png_get_uint_16(entry_start); entry_start += 2; 1777 } 1778 1779 pp->frequency = png_get_uint_16(entry_start); entry_start += 2; 1780 } 1781 #else 1782 pp = new_palette.entries; 1783 1784 for (i = 0; i < new_palette.nentries; i++) 1785 { 1786 1787 if (new_palette.depth == 8) 1788 { 1789 pp[i].red = *entry_start++; 1790 pp[i].green = *entry_start++; 1791 pp[i].blue = *entry_start++; 1792 pp[i].alpha = *entry_start++; 1793 } 1794 1795 else 1796 { 1797 pp[i].red = png_get_uint_16(entry_start); entry_start += 2; 1798 pp[i].green = png_get_uint_16(entry_start); entry_start += 2; 1799 pp[i].blue = png_get_uint_16(entry_start); entry_start += 2; 1800 pp[i].alpha = png_get_uint_16(entry_start); entry_start += 2; 1801 } 1802 1803 pp[i].frequency = png_get_uint_16(entry_start); entry_start += 2; 1804 } 1805 #endif 1806 1807 /* Discard all chunk data except the name and stash that */ 1808 new_palette.name = (png_charp)buffer; 1809 1810 png_set_sPLT(png_ptr, info_ptr, &new_palette, 1); 1811 1812 png_free(png_ptr, new_palette.entries); 1813 } 1814 #endif /* READ_sPLT */ 1815 1816 #ifdef PNG_READ_tRNS_SUPPORTED 1817 void /* PRIVATE */ 1818 png_handle_tRNS(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 1819 { 1820 png_byte readbuf[PNG_MAX_PALETTE_LENGTH]; 1821 1822 png_debug(1, "in png_handle_tRNS"); 1823 1824 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 1825 png_chunk_error(png_ptr, "missing IHDR"); 1826 1827 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) 1828 { 1829 png_crc_finish(png_ptr, length); 1830 png_chunk_benign_error(png_ptr, "out of place"); 1831 return; 1832 } 1833 1834 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS) != 0) 1835 { 1836 png_crc_finish(png_ptr, length); 1837 png_chunk_benign_error(png_ptr, "duplicate"); 1838 return; 1839 } 1840 1841 if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY) 1842 { 1843 png_byte buf[2]; 1844 1845 if (length != 2) 1846 { 1847 png_crc_finish(png_ptr, length); 1848 png_chunk_benign_error(png_ptr, "invalid"); 1849 return; 1850 } 1851 1852 png_crc_read(png_ptr, buf, 2); 1853 png_ptr->num_trans = 1; 1854 png_ptr->trans_color.gray = png_get_uint_16(buf); 1855 } 1856 1857 else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB) 1858 { 1859 png_byte buf[6]; 1860 1861 if (length != 6) 1862 { 1863 png_crc_finish(png_ptr, length); 1864 png_chunk_benign_error(png_ptr, "invalid"); 1865 return; 1866 } 1867 1868 png_crc_read(png_ptr, buf, length); 1869 png_ptr->num_trans = 1; 1870 png_ptr->trans_color.red = png_get_uint_16(buf); 1871 png_ptr->trans_color.green = png_get_uint_16(buf + 2); 1872 png_ptr->trans_color.blue = png_get_uint_16(buf + 4); 1873 } 1874 1875 else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) 1876 { 1877 if ((png_ptr->mode & PNG_HAVE_PLTE) == 0) 1878 { 1879 /* TODO: is this actually an error in the ISO spec? */ 1880 png_crc_finish(png_ptr, length); 1881 png_chunk_benign_error(png_ptr, "out of place"); 1882 return; 1883 } 1884 1885 if (length > (unsigned int) png_ptr->num_palette || 1886 length > (unsigned int) PNG_MAX_PALETTE_LENGTH || 1887 length == 0) 1888 { 1889 png_crc_finish(png_ptr, length); 1890 png_chunk_benign_error(png_ptr, "invalid"); 1891 return; 1892 } 1893 1894 png_crc_read(png_ptr, readbuf, length); 1895 png_ptr->num_trans = (png_uint_16)length; 1896 } 1897 1898 else 1899 { 1900 png_crc_finish(png_ptr, length); 1901 png_chunk_benign_error(png_ptr, "invalid with alpha channel"); 1902 return; 1903 } 1904 1905 if (png_crc_finish(png_ptr, 0) != 0) 1906 { 1907 png_ptr->num_trans = 0; 1908 return; 1909 } 1910 1911 /* TODO: this is a horrible side effect in the palette case because the 1912 * png_struct ends up with a pointer to the tRNS buffer owned by the 1913 * png_info. Fix this. 1914 */ 1915 png_set_tRNS(png_ptr, info_ptr, readbuf, png_ptr->num_trans, 1916 &(png_ptr->trans_color)); 1917 } 1918 #endif 1919 1920 #ifdef PNG_READ_bKGD_SUPPORTED 1921 void /* PRIVATE */ 1922 png_handle_bKGD(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 1923 { 1924 unsigned int truelen; 1925 png_byte buf[6]; 1926 png_color_16 background; 1927 1928 png_debug(1, "in png_handle_bKGD"); 1929 1930 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 1931 png_chunk_error(png_ptr, "missing IHDR"); 1932 1933 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0 || 1934 (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE && 1935 (png_ptr->mode & PNG_HAVE_PLTE) == 0)) 1936 { 1937 png_crc_finish(png_ptr, length); 1938 png_chunk_benign_error(png_ptr, "out of place"); 1939 return; 1940 } 1941 1942 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD) != 0) 1943 { 1944 png_crc_finish(png_ptr, length); 1945 png_chunk_benign_error(png_ptr, "duplicate"); 1946 return; 1947 } 1948 1949 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) 1950 truelen = 1; 1951 1952 else if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0) 1953 truelen = 6; 1954 1955 else 1956 truelen = 2; 1957 1958 if (length != truelen) 1959 { 1960 png_crc_finish(png_ptr, length); 1961 png_chunk_benign_error(png_ptr, "invalid"); 1962 return; 1963 } 1964 1965 png_crc_read(png_ptr, buf, truelen); 1966 1967 if (png_crc_finish(png_ptr, 0) != 0) 1968 return; 1969 1970 /* We convert the index value into RGB components so that we can allow 1971 * arbitrary RGB values for background when we have transparency, and 1972 * so it is easy to determine the RGB values of the background color 1973 * from the info_ptr struct. 1974 */ 1975 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) 1976 { 1977 background.index = buf[0]; 1978 1979 if (info_ptr != NULL && info_ptr->num_palette != 0) 1980 { 1981 if (buf[0] >= info_ptr->num_palette) 1982 { 1983 png_chunk_benign_error(png_ptr, "invalid index"); 1984 return; 1985 } 1986 1987 background.red = (png_uint_16)png_ptr->palette[buf[0]].red; 1988 background.green = (png_uint_16)png_ptr->palette[buf[0]].green; 1989 background.blue = (png_uint_16)png_ptr->palette[buf[0]].blue; 1990 } 1991 1992 else 1993 background.red = background.green = background.blue = 0; 1994 1995 background.gray = 0; 1996 } 1997 1998 else if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0) /* GRAY */ 1999 { 2000 background.index = 0; 2001 background.red = 2002 background.green = 2003 background.blue = 2004 background.gray = png_get_uint_16(buf); 2005 } 2006 2007 else 2008 { 2009 background.index = 0; 2010 background.red = png_get_uint_16(buf); 2011 background.green = png_get_uint_16(buf + 2); 2012 background.blue = png_get_uint_16(buf + 4); 2013 background.gray = 0; 2014 } 2015 2016 png_set_bKGD(png_ptr, info_ptr, &background); 2017 } 2018 #endif 2019 2020 #ifdef PNG_READ_eXIf_SUPPORTED 2021 void /* PRIVATE */ 2022 png_handle_eXIf(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 2023 { 2024 unsigned int i; 2025 2026 png_debug(1, "in png_handle_eXIf"); 2027 2028 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 2029 png_chunk_error(png_ptr, "missing IHDR"); 2030 2031 if (length < 2) 2032 { 2033 png_crc_finish(png_ptr, length); 2034 png_chunk_benign_error(png_ptr, "too short"); 2035 return; 2036 } 2037 2038 else if (info_ptr == NULL || (info_ptr->valid & PNG_INFO_eXIf) != 0) 2039 { 2040 png_crc_finish(png_ptr, length); 2041 png_chunk_benign_error(png_ptr, "duplicate"); 2042 return; 2043 } 2044 2045 info_ptr->free_me |= PNG_FREE_EXIF; 2046 2047 info_ptr->eXIf_buf = png_voidcast(png_bytep, 2048 png_malloc_warn(png_ptr, length)); 2049 2050 if (info_ptr->eXIf_buf == NULL) 2051 { 2052 png_crc_finish(png_ptr, length); 2053 png_chunk_benign_error(png_ptr, "out of memory"); 2054 return; 2055 } 2056 2057 for (i = 0; i < length; i++) 2058 { 2059 png_byte buf[1]; 2060 png_crc_read(png_ptr, buf, 1); 2061 info_ptr->eXIf_buf[i] = buf[0]; 2062 if (i == 1 && buf[0] != 'M' && buf[0] != 'I' 2063 && info_ptr->eXIf_buf[0] != buf[0]) 2064 { 2065 png_crc_finish(png_ptr, length); 2066 png_chunk_benign_error(png_ptr, "incorrect byte-order specifier"); 2067 png_free(png_ptr, info_ptr->eXIf_buf); 2068 info_ptr->eXIf_buf = NULL; 2069 return; 2070 } 2071 } 2072 2073 if (png_crc_finish(png_ptr, 0) != 0) 2074 return; 2075 2076 png_set_eXIf_1(png_ptr, info_ptr, length, info_ptr->eXIf_buf); 2077 2078 png_free(png_ptr, info_ptr->eXIf_buf); 2079 info_ptr->eXIf_buf = NULL; 2080 } 2081 #endif 2082 2083 #ifdef PNG_READ_hIST_SUPPORTED 2084 void /* PRIVATE */ 2085 png_handle_hIST(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 2086 { 2087 unsigned int num, i; 2088 png_uint_16 readbuf[PNG_MAX_PALETTE_LENGTH]; 2089 2090 png_debug(1, "in png_handle_hIST"); 2091 2092 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 2093 png_chunk_error(png_ptr, "missing IHDR"); 2094 2095 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0 || 2096 (png_ptr->mode & PNG_HAVE_PLTE) == 0) 2097 { 2098 png_crc_finish(png_ptr, length); 2099 png_chunk_benign_error(png_ptr, "out of place"); 2100 return; 2101 } 2102 2103 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST) != 0) 2104 { 2105 png_crc_finish(png_ptr, length); 2106 png_chunk_benign_error(png_ptr, "duplicate"); 2107 return; 2108 } 2109 2110 num = length / 2 ; 2111 2112 if (num != (unsigned int) png_ptr->num_palette || 2113 num > (unsigned int) PNG_MAX_PALETTE_LENGTH) 2114 { 2115 png_crc_finish(png_ptr, length); 2116 png_chunk_benign_error(png_ptr, "invalid"); 2117 return; 2118 } 2119 2120 for (i = 0; i < num; i++) 2121 { 2122 png_byte buf[2]; 2123 2124 png_crc_read(png_ptr, buf, 2); 2125 readbuf[i] = png_get_uint_16(buf); 2126 } 2127 2128 if (png_crc_finish(png_ptr, 0) != 0) 2129 return; 2130 2131 png_set_hIST(png_ptr, info_ptr, readbuf); 2132 } 2133 #endif 2134 2135 #ifdef PNG_READ_pHYs_SUPPORTED 2136 void /* PRIVATE */ 2137 png_handle_pHYs(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 2138 { 2139 png_byte buf[9]; 2140 png_uint_32 res_x, res_y; 2141 int unit_type; 2142 2143 png_debug(1, "in png_handle_pHYs"); 2144 2145 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 2146 png_chunk_error(png_ptr, "missing IHDR"); 2147 2148 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) 2149 { 2150 png_crc_finish(png_ptr, length); 2151 png_chunk_benign_error(png_ptr, "out of place"); 2152 return; 2153 } 2154 2155 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs) != 0) 2156 { 2157 png_crc_finish(png_ptr, length); 2158 png_chunk_benign_error(png_ptr, "duplicate"); 2159 return; 2160 } 2161 2162 if (length != 9) 2163 { 2164 png_crc_finish(png_ptr, length); 2165 png_chunk_benign_error(png_ptr, "invalid"); 2166 return; 2167 } 2168 2169 png_crc_read(png_ptr, buf, 9); 2170 2171 if (png_crc_finish(png_ptr, 0) != 0) 2172 return; 2173 2174 res_x = png_get_uint_32(buf); 2175 res_y = png_get_uint_32(buf + 4); 2176 unit_type = buf[8]; 2177 png_set_pHYs(png_ptr, info_ptr, res_x, res_y, unit_type); 2178 } 2179 #endif 2180 2181 #ifdef PNG_READ_oFFs_SUPPORTED 2182 void /* PRIVATE */ 2183 png_handle_oFFs(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 2184 { 2185 png_byte buf[9]; 2186 png_int_32 offset_x, offset_y; 2187 int unit_type; 2188 2189 png_debug(1, "in png_handle_oFFs"); 2190 2191 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 2192 png_chunk_error(png_ptr, "missing IHDR"); 2193 2194 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) 2195 { 2196 png_crc_finish(png_ptr, length); 2197 png_chunk_benign_error(png_ptr, "out of place"); 2198 return; 2199 } 2200 2201 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs) != 0) 2202 { 2203 png_crc_finish(png_ptr, length); 2204 png_chunk_benign_error(png_ptr, "duplicate"); 2205 return; 2206 } 2207 2208 if (length != 9) 2209 { 2210 png_crc_finish(png_ptr, length); 2211 png_chunk_benign_error(png_ptr, "invalid"); 2212 return; 2213 } 2214 2215 png_crc_read(png_ptr, buf, 9); 2216 2217 if (png_crc_finish(png_ptr, 0) != 0) 2218 return; 2219 2220 offset_x = png_get_int_32(buf); 2221 offset_y = png_get_int_32(buf + 4); 2222 unit_type = buf[8]; 2223 png_set_oFFs(png_ptr, info_ptr, offset_x, offset_y, unit_type); 2224 } 2225 #endif 2226 2227 #ifdef PNG_READ_pCAL_SUPPORTED 2228 /* Read the pCAL chunk (described in the PNG Extensions document) */ 2229 void /* PRIVATE */ 2230 png_handle_pCAL(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 2231 { 2232 png_int_32 X0, X1; 2233 png_byte type, nparams; 2234 png_bytep buffer, buf, units, endptr; 2235 png_charpp params; 2236 int i; 2237 2238 png_debug(1, "in png_handle_pCAL"); 2239 2240 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 2241 png_chunk_error(png_ptr, "missing IHDR"); 2242 2243 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) 2244 { 2245 png_crc_finish(png_ptr, length); 2246 png_chunk_benign_error(png_ptr, "out of place"); 2247 return; 2248 } 2249 2250 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pCAL) != 0) 2251 { 2252 png_crc_finish(png_ptr, length); 2253 png_chunk_benign_error(png_ptr, "duplicate"); 2254 return; 2255 } 2256 2257 png_debug1(2, "Allocating and reading pCAL chunk data (%u bytes)", 2258 length + 1); 2259 2260 buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/); 2261 2262 if (buffer == NULL) 2263 { 2264 png_crc_finish(png_ptr, length); 2265 png_chunk_benign_error(png_ptr, "out of memory"); 2266 return; 2267 } 2268 2269 png_crc_read(png_ptr, buffer, length); 2270 2271 if (png_crc_finish(png_ptr, 0) != 0) 2272 return; 2273 2274 buffer[length] = 0; /* Null terminate the last string */ 2275 2276 png_debug(3, "Finding end of pCAL purpose string"); 2277 for (buf = buffer; *buf; buf++) 2278 /* Empty loop */ ; 2279 2280 endptr = buffer + length; 2281 2282 /* We need to have at least 12 bytes after the purpose string 2283 * in order to get the parameter information. 2284 */ 2285 if (endptr - buf <= 12) 2286 { 2287 png_chunk_benign_error(png_ptr, "invalid"); 2288 return; 2289 } 2290 2291 png_debug(3, "Reading pCAL X0, X1, type, nparams, and units"); 2292 X0 = png_get_int_32((png_bytep)buf+1); 2293 X1 = png_get_int_32((png_bytep)buf+5); 2294 type = buf[9]; 2295 nparams = buf[10]; 2296 units = buf + 11; 2297 2298 png_debug(3, "Checking pCAL equation type and number of parameters"); 2299 /* Check that we have the right number of parameters for known 2300 * equation types. 2301 */ 2302 if ((type == PNG_EQUATION_LINEAR && nparams != 2) || 2303 (type == PNG_EQUATION_BASE_E && nparams != 3) || 2304 (type == PNG_EQUATION_ARBITRARY && nparams != 3) || 2305 (type == PNG_EQUATION_HYPERBOLIC && nparams != 4)) 2306 { 2307 png_chunk_benign_error(png_ptr, "invalid parameter count"); 2308 return; 2309 } 2310 2311 else if (type >= PNG_EQUATION_LAST) 2312 { 2313 png_chunk_benign_error(png_ptr, "unrecognized equation type"); 2314 } 2315 2316 for (buf = units; *buf; buf++) 2317 /* Empty loop to move past the units string. */ ; 2318 2319 png_debug(3, "Allocating pCAL parameters array"); 2320 2321 params = png_voidcast(png_charpp, png_malloc_warn(png_ptr, 2322 nparams * (sizeof (png_charp)))); 2323 2324 if (params == NULL) 2325 { 2326 png_chunk_benign_error(png_ptr, "out of memory"); 2327 return; 2328 } 2329 2330 /* Get pointers to the start of each parameter string. */ 2331 for (i = 0; i < nparams; i++) 2332 { 2333 buf++; /* Skip the null string terminator from previous parameter. */ 2334 2335 png_debug1(3, "Reading pCAL parameter %d", i); 2336 2337 for (params[i] = (png_charp)buf; buf <= endptr && *buf != 0; buf++) 2338 /* Empty loop to move past each parameter string */ ; 2339 2340 /* Make sure we haven't run out of data yet */ 2341 if (buf > endptr) 2342 { 2343 png_free(png_ptr, params); 2344 png_chunk_benign_error(png_ptr, "invalid data"); 2345 return; 2346 } 2347 } 2348 2349 png_set_pCAL(png_ptr, info_ptr, (png_charp)buffer, X0, X1, type, nparams, 2350 (png_charp)units, params); 2351 2352 png_free(png_ptr, params); 2353 } 2354 #endif 2355 2356 #ifdef PNG_READ_sCAL_SUPPORTED 2357 /* Read the sCAL chunk */ 2358 void /* PRIVATE */ 2359 png_handle_sCAL(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 2360 { 2361 png_bytep buffer; 2362 png_size_t i; 2363 int state; 2364 2365 png_debug(1, "in png_handle_sCAL"); 2366 2367 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 2368 png_chunk_error(png_ptr, "missing IHDR"); 2369 2370 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) 2371 { 2372 png_crc_finish(png_ptr, length); 2373 png_chunk_benign_error(png_ptr, "out of place"); 2374 return; 2375 } 2376 2377 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sCAL) != 0) 2378 { 2379 png_crc_finish(png_ptr, length); 2380 png_chunk_benign_error(png_ptr, "duplicate"); 2381 return; 2382 } 2383 2384 /* Need unit type, width, \0, height: minimum 4 bytes */ 2385 else if (length < 4) 2386 { 2387 png_crc_finish(png_ptr, length); 2388 png_chunk_benign_error(png_ptr, "invalid"); 2389 return; 2390 } 2391 2392 png_debug1(2, "Allocating and reading sCAL chunk data (%u bytes)", 2393 length + 1); 2394 2395 buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/); 2396 2397 if (buffer == NULL) 2398 { 2399 png_chunk_benign_error(png_ptr, "out of memory"); 2400 png_crc_finish(png_ptr, length); 2401 return; 2402 } 2403 2404 png_crc_read(png_ptr, buffer, length); 2405 buffer[length] = 0; /* Null terminate the last string */ 2406 2407 if (png_crc_finish(png_ptr, 0) != 0) 2408 return; 2409 2410 /* Validate the unit. */ 2411 if (buffer[0] != 1 && buffer[0] != 2) 2412 { 2413 png_chunk_benign_error(png_ptr, "invalid unit"); 2414 return; 2415 } 2416 2417 /* Validate the ASCII numbers, need two ASCII numbers separated by 2418 * a '\0' and they need to fit exactly in the chunk data. 2419 */ 2420 i = 1; 2421 state = 0; 2422 2423 if (png_check_fp_number((png_const_charp)buffer, length, &state, &i) == 0 || 2424 i >= length || buffer[i++] != 0) 2425 png_chunk_benign_error(png_ptr, "bad width format"); 2426 2427 else if (PNG_FP_IS_POSITIVE(state) == 0) 2428 png_chunk_benign_error(png_ptr, "non-positive width"); 2429 2430 else 2431 { 2432 png_size_t heighti = i; 2433 2434 state = 0; 2435 if (png_check_fp_number((png_const_charp)buffer, length, 2436 &state, &i) == 0 || i != length) 2437 png_chunk_benign_error(png_ptr, "bad height format"); 2438 2439 else if (PNG_FP_IS_POSITIVE(state) == 0) 2440 png_chunk_benign_error(png_ptr, "non-positive height"); 2441 2442 else 2443 /* This is the (only) success case. */ 2444 png_set_sCAL_s(png_ptr, info_ptr, buffer[0], 2445 (png_charp)buffer+1, (png_charp)buffer+heighti); 2446 } 2447 } 2448 #endif 2449 2450 #ifdef PNG_READ_tIME_SUPPORTED 2451 void /* PRIVATE */ 2452 png_handle_tIME(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 2453 { 2454 png_byte buf[7]; 2455 png_time mod_time; 2456 2457 png_debug(1, "in png_handle_tIME"); 2458 2459 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 2460 png_chunk_error(png_ptr, "missing IHDR"); 2461 2462 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tIME) != 0) 2463 { 2464 png_crc_finish(png_ptr, length); 2465 png_chunk_benign_error(png_ptr, "duplicate"); 2466 return; 2467 } 2468 2469 if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) 2470 png_ptr->mode |= PNG_AFTER_IDAT; 2471 2472 if (length != 7) 2473 { 2474 png_crc_finish(png_ptr, length); 2475 png_chunk_benign_error(png_ptr, "invalid"); 2476 return; 2477 } 2478 2479 png_crc_read(png_ptr, buf, 7); 2480 2481 if (png_crc_finish(png_ptr, 0) != 0) 2482 return; 2483 2484 mod_time.second = buf[6]; 2485 mod_time.minute = buf[5]; 2486 mod_time.hour = buf[4]; 2487 mod_time.day = buf[3]; 2488 mod_time.month = buf[2]; 2489 mod_time.year = png_get_uint_16(buf); 2490 2491 png_set_tIME(png_ptr, info_ptr, &mod_time); 2492 } 2493 #endif 2494 2495 #ifdef PNG_READ_tEXt_SUPPORTED 2496 /* Note: this does not properly handle chunks that are > 64K under DOS */ 2497 void /* PRIVATE */ 2498 png_handle_tEXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 2499 { 2500 png_text text_info; 2501 png_bytep buffer; 2502 png_charp key; 2503 png_charp text; 2504 png_uint_32 skip = 0; 2505 2506 png_debug(1, "in png_handle_tEXt"); 2507 2508 #ifdef PNG_USER_LIMITS_SUPPORTED 2509 if (png_ptr->user_chunk_cache_max != 0) 2510 { 2511 if (png_ptr->user_chunk_cache_max == 1) 2512 { 2513 png_crc_finish(png_ptr, length); 2514 return; 2515 } 2516 2517 if (--png_ptr->user_chunk_cache_max == 1) 2518 { 2519 png_crc_finish(png_ptr, length); 2520 png_chunk_benign_error(png_ptr, "no space in chunk cache"); 2521 return; 2522 } 2523 } 2524 #endif 2525 2526 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 2527 png_chunk_error(png_ptr, "missing IHDR"); 2528 2529 if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) 2530 png_ptr->mode |= PNG_AFTER_IDAT; 2531 2532 #ifdef PNG_MAX_MALLOC_64K 2533 if (length > 65535U) 2534 { 2535 png_crc_finish(png_ptr, length); 2536 png_chunk_benign_error(png_ptr, "too large to fit in memory"); 2537 return; 2538 } 2539 #endif 2540 2541 buffer = png_read_buffer(png_ptr, length+1, 1/*warn*/); 2542 2543 if (buffer == NULL) 2544 { 2545 png_chunk_benign_error(png_ptr, "out of memory"); 2546 return; 2547 } 2548 2549 png_crc_read(png_ptr, buffer, length); 2550 2551 if (png_crc_finish(png_ptr, skip) != 0) 2552 return; 2553 2554 key = (png_charp)buffer; 2555 key[length] = 0; 2556 2557 for (text = key; *text; text++) 2558 /* Empty loop to find end of key */ ; 2559 2560 if (text != key + length) 2561 text++; 2562 2563 text_info.compression = PNG_TEXT_COMPRESSION_NONE; 2564 text_info.key = key; 2565 text_info.lang = NULL; 2566 text_info.lang_key = NULL; 2567 text_info.itxt_length = 0; 2568 text_info.text = text; 2569 text_info.text_length = strlen(text); 2570 2571 if (png_set_text_2(png_ptr, info_ptr, &text_info, 1) != 0) 2572 png_warning(png_ptr, "Insufficient memory to process text chunk"); 2573 } 2574 #endif 2575 2576 #ifdef PNG_READ_zTXt_SUPPORTED 2577 /* Note: this does not correctly handle chunks that are > 64K under DOS */ 2578 void /* PRIVATE */ 2579 png_handle_zTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 2580 { 2581 png_const_charp errmsg = NULL; 2582 png_bytep buffer; 2583 png_uint_32 keyword_length; 2584 2585 png_debug(1, "in png_handle_zTXt"); 2586 2587 #ifdef PNG_USER_LIMITS_SUPPORTED 2588 if (png_ptr->user_chunk_cache_max != 0) 2589 { 2590 if (png_ptr->user_chunk_cache_max == 1) 2591 { 2592 png_crc_finish(png_ptr, length); 2593 return; 2594 } 2595 2596 if (--png_ptr->user_chunk_cache_max == 1) 2597 { 2598 png_crc_finish(png_ptr, length); 2599 png_chunk_benign_error(png_ptr, "no space in chunk cache"); 2600 return; 2601 } 2602 } 2603 #endif 2604 2605 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 2606 png_chunk_error(png_ptr, "missing IHDR"); 2607 2608 if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) 2609 png_ptr->mode |= PNG_AFTER_IDAT; 2610 2611 /* Note, "length" is sufficient here; we won't be adding 2612 * a null terminator later. 2613 */ 2614 buffer = png_read_buffer(png_ptr, length, 2/*silent*/); 2615 2616 if (buffer == NULL) 2617 { 2618 png_crc_finish(png_ptr, length); 2619 png_chunk_benign_error(png_ptr, "out of memory"); 2620 return; 2621 } 2622 2623 png_crc_read(png_ptr, buffer, length); 2624 2625 if (png_crc_finish(png_ptr, 0) != 0) 2626 return; 2627 2628 /* TODO: also check that the keyword contents match the spec! */ 2629 for (keyword_length = 0; 2630 keyword_length < length && buffer[keyword_length] != 0; 2631 ++keyword_length) 2632 /* Empty loop to find end of name */ ; 2633 2634 if (keyword_length > 79 || keyword_length < 1) 2635 errmsg = "bad keyword"; 2636 2637 /* zTXt must have some LZ data after the keyword, although it may expand to 2638 * zero bytes; we need a '\0' at the end of the keyword, the compression type 2639 * then the LZ data: 2640 */ 2641 else if (keyword_length + 3 > length) 2642 errmsg = "truncated"; 2643 2644 else if (buffer[keyword_length+1] != PNG_COMPRESSION_TYPE_BASE) 2645 errmsg = "unknown compression type"; 2646 2647 else 2648 { 2649 png_alloc_size_t uncompressed_length = PNG_SIZE_MAX; 2650 2651 /* TODO: at present png_decompress_chunk imposes a single application 2652 * level memory limit, this should be split to different values for iCCP 2653 * and text chunks. 2654 */ 2655 if (png_decompress_chunk(png_ptr, length, keyword_length+2, 2656 &uncompressed_length, 1/*terminate*/) == Z_STREAM_END) 2657 { 2658 png_text text; 2659 2660 if (png_ptr->read_buffer == NULL) 2661 errmsg="Read failure in png_handle_zTXt"; 2662 else 2663 { 2664 /* It worked; png_ptr->read_buffer now looks like a tEXt chunk 2665 * except for the extra compression type byte and the fact that 2666 * it isn't necessarily '\0' terminated. 2667 */ 2668 buffer = png_ptr->read_buffer; 2669 buffer[uncompressed_length+(keyword_length+2)] = 0; 2670 2671 text.compression = PNG_TEXT_COMPRESSION_zTXt; 2672 text.key = (png_charp)buffer; 2673 text.text = (png_charp)(buffer + keyword_length+2); 2674 text.text_length = uncompressed_length; 2675 text.itxt_length = 0; 2676 text.lang = NULL; 2677 text.lang_key = NULL; 2678 2679 if (png_set_text_2(png_ptr, info_ptr, &text, 1) != 0) 2680 errmsg = "insufficient memory"; 2681 } 2682 } 2683 2684 else 2685 errmsg = png_ptr->zstream.msg; 2686 } 2687 2688 if (errmsg != NULL) 2689 png_chunk_benign_error(png_ptr, errmsg); 2690 } 2691 #endif 2692 2693 #ifdef PNG_READ_iTXt_SUPPORTED 2694 /* Note: this does not correctly handle chunks that are > 64K under DOS */ 2695 void /* PRIVATE */ 2696 png_handle_iTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 2697 { 2698 png_const_charp errmsg = NULL; 2699 png_bytep buffer; 2700 png_uint_32 prefix_length; 2701 2702 png_debug(1, "in png_handle_iTXt"); 2703 2704 #ifdef PNG_USER_LIMITS_SUPPORTED 2705 if (png_ptr->user_chunk_cache_max != 0) 2706 { 2707 if (png_ptr->user_chunk_cache_max == 1) 2708 { 2709 png_crc_finish(png_ptr, length); 2710 return; 2711 } 2712 2713 if (--png_ptr->user_chunk_cache_max == 1) 2714 { 2715 png_crc_finish(png_ptr, length); 2716 png_chunk_benign_error(png_ptr, "no space in chunk cache"); 2717 return; 2718 } 2719 } 2720 #endif 2721 2722 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 2723 png_chunk_error(png_ptr, "missing IHDR"); 2724 2725 if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) 2726 png_ptr->mode |= PNG_AFTER_IDAT; 2727 2728 buffer = png_read_buffer(png_ptr, length+1, 1/*warn*/); 2729 2730 if (buffer == NULL) 2731 { 2732 png_crc_finish(png_ptr, length); 2733 png_chunk_benign_error(png_ptr, "out of memory"); 2734 return; 2735 } 2736 2737 png_crc_read(png_ptr, buffer, length); 2738 2739 if (png_crc_finish(png_ptr, 0) != 0) 2740 return; 2741 2742 /* First the keyword. */ 2743 for (prefix_length=0; 2744 prefix_length < length && buffer[prefix_length] != 0; 2745 ++prefix_length) 2746 /* Empty loop */ ; 2747 2748 /* Perform a basic check on the keyword length here. */ 2749 if (prefix_length > 79 || prefix_length < 1) 2750 errmsg = "bad keyword"; 2751 2752 /* Expect keyword, compression flag, compression type, language, translated 2753 * keyword (both may be empty but are 0 terminated) then the text, which may 2754 * be empty. 2755 */ 2756 else if (prefix_length + 5 > length) 2757 errmsg = "truncated"; 2758 2759 else if (buffer[prefix_length+1] == 0 || 2760 (buffer[prefix_length+1] == 1 && 2761 buffer[prefix_length+2] == PNG_COMPRESSION_TYPE_BASE)) 2762 { 2763 int compressed = buffer[prefix_length+1] != 0; 2764 png_uint_32 language_offset, translated_keyword_offset; 2765 png_alloc_size_t uncompressed_length = 0; 2766 2767 /* Now the language tag */ 2768 prefix_length += 3; 2769 language_offset = prefix_length; 2770 2771 for (; prefix_length < length && buffer[prefix_length] != 0; 2772 ++prefix_length) 2773 /* Empty loop */ ; 2774 2775 /* WARNING: the length may be invalid here, this is checked below. */ 2776 translated_keyword_offset = ++prefix_length; 2777 2778 for (; prefix_length < length && buffer[prefix_length] != 0; 2779 ++prefix_length) 2780 /* Empty loop */ ; 2781 2782 /* prefix_length should now be at the trailing '\0' of the translated 2783 * keyword, but it may already be over the end. None of this arithmetic 2784 * can overflow because chunks are at most 2^31 bytes long, but on 16-bit 2785 * systems the available allocation may overflow. 2786 */ 2787 ++prefix_length; 2788 2789 if (compressed == 0 && prefix_length <= length) 2790 uncompressed_length = length - prefix_length; 2791 2792 else if (compressed != 0 && prefix_length < length) 2793 { 2794 uncompressed_length = PNG_SIZE_MAX; 2795 2796 /* TODO: at present png_decompress_chunk imposes a single application 2797 * level memory limit, this should be split to different values for 2798 * iCCP and text chunks. 2799 */ 2800 if (png_decompress_chunk(png_ptr, length, prefix_length, 2801 &uncompressed_length, 1/*terminate*/) == Z_STREAM_END) 2802 buffer = png_ptr->read_buffer; 2803 2804 else 2805 errmsg = png_ptr->zstream.msg; 2806 } 2807 2808 else 2809 errmsg = "truncated"; 2810 2811 if (errmsg == NULL) 2812 { 2813 png_text text; 2814 2815 buffer[uncompressed_length+prefix_length] = 0; 2816 2817 if (compressed == 0) 2818 text.compression = PNG_ITXT_COMPRESSION_NONE; 2819 2820 else 2821 text.compression = PNG_ITXT_COMPRESSION_zTXt; 2822 2823 text.key = (png_charp)buffer; 2824 text.lang = (png_charp)buffer + language_offset; 2825 text.lang_key = (png_charp)buffer + translated_keyword_offset; 2826 text.text = (png_charp)buffer + prefix_length; 2827 text.text_length = 0; 2828 text.itxt_length = uncompressed_length; 2829 2830 if (png_set_text_2(png_ptr, info_ptr, &text, 1) != 0) 2831 errmsg = "insufficient memory"; 2832 } 2833 } 2834 2835 else 2836 errmsg = "bad compression info"; 2837 2838 if (errmsg != NULL) 2839 png_chunk_benign_error(png_ptr, errmsg); 2840 } 2841 #endif 2842 2843 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED 2844 /* Utility function for png_handle_unknown; set up png_ptr::unknown_chunk */ 2845 static int 2846 png_cache_unknown_chunk(png_structrp png_ptr, png_uint_32 length) 2847 { 2848 png_alloc_size_t limit = PNG_SIZE_MAX; 2849 2850 if (png_ptr->unknown_chunk.data != NULL) 2851 { 2852 png_free(png_ptr, png_ptr->unknown_chunk.data); 2853 png_ptr->unknown_chunk.data = NULL; 2854 } 2855 2856 # ifdef PNG_SET_USER_LIMITS_SUPPORTED 2857 if (png_ptr->user_chunk_malloc_max > 0 && 2858 png_ptr->user_chunk_malloc_max < limit) 2859 limit = png_ptr->user_chunk_malloc_max; 2860 2861 # elif PNG_USER_CHUNK_MALLOC_MAX > 0 2862 if (PNG_USER_CHUNK_MALLOC_MAX < limit) 2863 limit = PNG_USER_CHUNK_MALLOC_MAX; 2864 # endif 2865 2866 if (length <= limit) 2867 { 2868 PNG_CSTRING_FROM_CHUNK(png_ptr->unknown_chunk.name, png_ptr->chunk_name); 2869 /* The following is safe because of the PNG_SIZE_MAX init above */ 2870 png_ptr->unknown_chunk.size = (png_size_t)length/*SAFE*/; 2871 /* 'mode' is a flag array, only the bottom four bits matter here */ 2872 png_ptr->unknown_chunk.location = (png_byte)png_ptr->mode/*SAFE*/; 2873 2874 if (length == 0) 2875 png_ptr->unknown_chunk.data = NULL; 2876 2877 else 2878 { 2879 /* Do a 'warn' here - it is handled below. */ 2880 png_ptr->unknown_chunk.data = png_voidcast(png_bytep, 2881 png_malloc_warn(png_ptr, length)); 2882 } 2883 } 2884 2885 if (png_ptr->unknown_chunk.data == NULL && length > 0) 2886 { 2887 /* This is benign because we clean up correctly */ 2888 png_crc_finish(png_ptr, length); 2889 png_chunk_benign_error(png_ptr, "unknown chunk exceeds memory limits"); 2890 return 0; 2891 } 2892 2893 else 2894 { 2895 if (length > 0) 2896 png_crc_read(png_ptr, png_ptr->unknown_chunk.data, length); 2897 png_crc_finish(png_ptr, 0); 2898 return 1; 2899 } 2900 } 2901 #endif /* READ_UNKNOWN_CHUNKS */ 2902 2903 /* Handle an unknown, or known but disabled, chunk */ 2904 void /* PRIVATE */ 2905 png_handle_unknown(png_structrp png_ptr, png_inforp info_ptr, 2906 png_uint_32 length, int keep) 2907 { 2908 int handled = 0; /* the chunk was handled */ 2909 2910 png_debug(1, "in png_handle_unknown"); 2911 2912 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED 2913 /* NOTE: this code is based on the code in libpng-1.4.12 except for fixing 2914 * the bug which meant that setting a non-default behavior for a specific 2915 * chunk would be ignored (the default was always used unless a user 2916 * callback was installed). 2917 * 2918 * 'keep' is the value from the png_chunk_unknown_handling, the setting for 2919 * this specific chunk_name, if PNG_HANDLE_AS_UNKNOWN_SUPPORTED, if not it 2920 * will always be PNG_HANDLE_CHUNK_AS_DEFAULT and it needs to be set here. 2921 * This is just an optimization to avoid multiple calls to the lookup 2922 * function. 2923 */ 2924 # ifndef PNG_HANDLE_AS_UNKNOWN_SUPPORTED 2925 # ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED 2926 keep = png_chunk_unknown_handling(png_ptr, png_ptr->chunk_name); 2927 # endif 2928 # endif 2929 2930 /* One of the following methods will read the chunk or skip it (at least one 2931 * of these is always defined because this is the only way to switch on 2932 * PNG_READ_UNKNOWN_CHUNKS_SUPPORTED) 2933 */ 2934 # ifdef PNG_READ_USER_CHUNKS_SUPPORTED 2935 /* The user callback takes precedence over the chunk keep value, but the 2936 * keep value is still required to validate a save of a critical chunk. 2937 */ 2938 if (png_ptr->read_user_chunk_fn != NULL) 2939 { 2940 if (png_cache_unknown_chunk(png_ptr, length) != 0) 2941 { 2942 /* Callback to user unknown chunk handler */ 2943 int ret = (*(png_ptr->read_user_chunk_fn))(png_ptr, 2944 &png_ptr->unknown_chunk); 2945 2946 /* ret is: 2947 * negative: An error occurred; png_chunk_error will be called. 2948 * zero: The chunk was not handled, the chunk will be discarded 2949 * unless png_set_keep_unknown_chunks has been used to set 2950 * a 'keep' behavior for this particular chunk, in which 2951 * case that will be used. A critical chunk will cause an 2952 * error at this point unless it is to be saved. 2953 * positive: The chunk was handled, libpng will ignore/discard it. 2954 */ 2955 if (ret < 0) 2956 png_chunk_error(png_ptr, "error in user chunk"); 2957 2958 else if (ret == 0) 2959 { 2960 /* If the keep value is 'default' or 'never' override it, but 2961 * still error out on critical chunks unless the keep value is 2962 * 'always' While this is weird it is the behavior in 1.4.12. 2963 * A possible improvement would be to obey the value set for the 2964 * chunk, but this would be an API change that would probably 2965 * damage some applications. 2966 * 2967 * The png_app_warning below catches the case that matters, where 2968 * the application has not set specific save or ignore for this 2969 * chunk or global save or ignore. 2970 */ 2971 if (keep < PNG_HANDLE_CHUNK_IF_SAFE) 2972 { 2973 # ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED 2974 if (png_ptr->unknown_default < PNG_HANDLE_CHUNK_IF_SAFE) 2975 { 2976 png_chunk_warning(png_ptr, "Saving unknown chunk:"); 2977 png_app_warning(png_ptr, 2978 "forcing save of an unhandled chunk;" 2979 " please call png_set_keep_unknown_chunks"); 2980 /* with keep = PNG_HANDLE_CHUNK_IF_SAFE */ 2981 } 2982 # endif 2983 keep = PNG_HANDLE_CHUNK_IF_SAFE; 2984 } 2985 } 2986 2987 else /* chunk was handled */ 2988 { 2989 handled = 1; 2990 /* Critical chunks can be safely discarded at this point. */ 2991 keep = PNG_HANDLE_CHUNK_NEVER; 2992 } 2993 } 2994 2995 else 2996 keep = PNG_HANDLE_CHUNK_NEVER; /* insufficient memory */ 2997 } 2998 2999 else 3000 /* Use the SAVE_UNKNOWN_CHUNKS code or skip the chunk */ 3001 # endif /* READ_USER_CHUNKS */ 3002 3003 # ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED 3004 { 3005 /* keep is currently just the per-chunk setting, if there was no 3006 * setting change it to the global default now (not that this may 3007 * still be AS_DEFAULT) then obtain the cache of the chunk if required, 3008 * if not simply skip the chunk. 3009 */ 3010 if (keep == PNG_HANDLE_CHUNK_AS_DEFAULT) 3011 keep = png_ptr->unknown_default; 3012 3013 if (keep == PNG_HANDLE_CHUNK_ALWAYS || 3014 (keep == PNG_HANDLE_CHUNK_IF_SAFE && 3015 PNG_CHUNK_ANCILLARY(png_ptr->chunk_name))) 3016 { 3017 if (png_cache_unknown_chunk(png_ptr, length) == 0) 3018 keep = PNG_HANDLE_CHUNK_NEVER; 3019 } 3020 3021 else 3022 png_crc_finish(png_ptr, length); 3023 } 3024 # else 3025 # ifndef PNG_READ_USER_CHUNKS_SUPPORTED 3026 # error no method to support READ_UNKNOWN_CHUNKS 3027 # endif 3028 3029 { 3030 /* If here there is no read callback pointer set and no support is 3031 * compiled in to just save the unknown chunks, so simply skip this 3032 * chunk. If 'keep' is something other than AS_DEFAULT or NEVER then 3033 * the app has erroneously asked for unknown chunk saving when there 3034 * is no support. 3035 */ 3036 if (keep > PNG_HANDLE_CHUNK_NEVER) 3037 png_app_error(png_ptr, "no unknown chunk support available"); 3038 3039 png_crc_finish(png_ptr, length); 3040 } 3041 # endif 3042 3043 # ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED 3044 /* Now store the chunk in the chunk list if appropriate, and if the limits 3045 * permit it. 3046 */ 3047 if (keep == PNG_HANDLE_CHUNK_ALWAYS || 3048 (keep == PNG_HANDLE_CHUNK_IF_SAFE && 3049 PNG_CHUNK_ANCILLARY(png_ptr->chunk_name))) 3050 { 3051 # ifdef PNG_USER_LIMITS_SUPPORTED 3052 switch (png_ptr->user_chunk_cache_max) 3053 { 3054 case 2: 3055 png_ptr->user_chunk_cache_max = 1; 3056 png_chunk_benign_error(png_ptr, "no space in chunk cache"); 3057 /* FALLTHROUGH */ 3058 case 1: 3059 /* NOTE: prior to 1.6.0 this case resulted in an unknown critical 3060 * chunk being skipped, now there will be a hard error below. 3061 */ 3062 break; 3063 3064 default: /* not at limit */ 3065 --(png_ptr->user_chunk_cache_max); 3066 /* FALLTHROUGH */ 3067 case 0: /* no limit */ 3068 # endif /* USER_LIMITS */ 3069 /* Here when the limit isn't reached or when limits are compiled 3070 * out; store the chunk. 3071 */ 3072 png_set_unknown_chunks(png_ptr, info_ptr, 3073 &png_ptr->unknown_chunk, 1); 3074 handled = 1; 3075 # ifdef PNG_USER_LIMITS_SUPPORTED 3076 break; 3077 } 3078 # endif 3079 } 3080 # else /* no store support: the chunk must be handled by the user callback */ 3081 PNG_UNUSED(info_ptr) 3082 # endif 3083 3084 /* Regardless of the error handling below the cached data (if any) can be 3085 * freed now. Notice that the data is not freed if there is a png_error, but 3086 * it will be freed by destroy_read_struct. 3087 */ 3088 if (png_ptr->unknown_chunk.data != NULL) 3089 png_free(png_ptr, png_ptr->unknown_chunk.data); 3090 png_ptr->unknown_chunk.data = NULL; 3091 3092 #else /* !PNG_READ_UNKNOWN_CHUNKS_SUPPORTED */ 3093 /* There is no support to read an unknown chunk, so just skip it. */ 3094 png_crc_finish(png_ptr, length); 3095 PNG_UNUSED(info_ptr) 3096 PNG_UNUSED(keep) 3097 #endif /* !READ_UNKNOWN_CHUNKS */ 3098 3099 /* Check for unhandled critical chunks */ 3100 if (handled == 0 && PNG_CHUNK_CRITICAL(png_ptr->chunk_name)) 3101 png_chunk_error(png_ptr, "unhandled critical chunk"); 3102 } 3103 3104 /* This function is called to verify that a chunk name is valid. 3105 * This function can't have the "critical chunk check" incorporated 3106 * into it, since in the future we will need to be able to call user 3107 * functions to handle unknown critical chunks after we check that 3108 * the chunk name itself is valid. 3109 */ 3110 3111 /* Bit hacking: the test for an invalid byte in the 4 byte chunk name is: 3112 * 3113 * ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97)) 3114 */ 3115 3116 void /* PRIVATE */ 3117 png_check_chunk_name(png_const_structrp png_ptr, const png_uint_32 chunk_name) 3118 { 3119 int i; 3120 png_uint_32 cn=chunk_name; 3121 3122 png_debug(1, "in png_check_chunk_name"); 3123 3124 for (i=1; i<=4; ++i) 3125 { 3126 int c = cn & 0xff; 3127 3128 if (c < 65 || c > 122 || (c > 90 && c < 97)) 3129 png_chunk_error(png_ptr, "invalid chunk type"); 3130 3131 cn >>= 8; 3132 } 3133 } 3134 3135 void /* PRIVATE */ 3136 png_check_chunk_length(png_const_structrp png_ptr, const png_uint_32 length) 3137 { 3138 png_alloc_size_t limit = PNG_UINT_31_MAX; 3139 3140 # ifdef PNG_SET_USER_LIMITS_SUPPORTED 3141 if (png_ptr->user_chunk_malloc_max > 0 && 3142 png_ptr->user_chunk_malloc_max < limit) 3143 limit = png_ptr->user_chunk_malloc_max; 3144 # elif PNG_USER_CHUNK_MALLOC_MAX > 0 3145 if (PNG_USER_CHUNK_MALLOC_MAX < limit) 3146 limit = PNG_USER_CHUNK_MALLOC_MAX; 3147 # endif 3148 if (png_ptr->chunk_name == png_IDAT) 3149 { 3150 png_alloc_size_t idat_limit = PNG_UINT_31_MAX; 3151 size_t row_factor = 3152 (png_ptr->width * png_ptr->channels * (png_ptr->bit_depth > 8? 2: 1) 3153 + 1 + (png_ptr->interlaced? 6: 0)); 3154 if (png_ptr->height > PNG_UINT_32_MAX/row_factor) 3155 idat_limit=PNG_UINT_31_MAX; 3156 else 3157 idat_limit = png_ptr->height * row_factor; 3158 row_factor = row_factor > 32566? 32566 : row_factor; 3159 idat_limit += 6 + 5*(idat_limit/row_factor+1); /* zlib+deflate overhead */ 3160 idat_limit=idat_limit < PNG_UINT_31_MAX? idat_limit : PNG_UINT_31_MAX; 3161 limit = limit < idat_limit? idat_limit : limit; 3162 } 3163 3164 if (length > limit) 3165 { 3166 png_debug2(0," length = %lu, limit = %lu", 3167 (unsigned long)length,(unsigned long)limit); 3168 png_chunk_error(png_ptr, "chunk data is too large"); 3169 } 3170 } 3171 3172 /* Combines the row recently read in with the existing pixels in the row. This 3173 * routine takes care of alpha and transparency if requested. This routine also 3174 * handles the two methods of progressive display of interlaced images, 3175 * depending on the 'display' value; if 'display' is true then the whole row 3176 * (dp) is filled from the start by replicating the available pixels. If 3177 * 'display' is false only those pixels present in the pass are filled in. 3178 */ 3179 void /* PRIVATE */ 3180 png_combine_row(png_const_structrp png_ptr, png_bytep dp, int display) 3181 { 3182 unsigned int pixel_depth = png_ptr->transformed_pixel_depth; 3183 png_const_bytep sp = png_ptr->row_buf + 1; 3184 png_alloc_size_t row_width = png_ptr->width; 3185 unsigned int pass = png_ptr->pass; 3186 png_bytep end_ptr = 0; 3187 png_byte end_byte = 0; 3188 unsigned int end_mask; 3189 3190 png_debug(1, "in png_combine_row"); 3191 3192 /* Added in 1.5.6: it should not be possible to enter this routine until at 3193 * least one row has been read from the PNG data and transformed. 3194 */ 3195 if (pixel_depth == 0) 3196 png_error(png_ptr, "internal row logic error"); 3197 3198 /* Added in 1.5.4: the pixel depth should match the information returned by 3199 * any call to png_read_update_info at this point. Do not continue if we got 3200 * this wrong. 3201 */ 3202 if (png_ptr->info_rowbytes != 0 && png_ptr->info_rowbytes != 3203 PNG_ROWBYTES(pixel_depth, row_width)) 3204 png_error(png_ptr, "internal row size calculation error"); 3205 3206 /* Don't expect this to ever happen: */ 3207 if (row_width == 0) 3208 png_error(png_ptr, "internal row width error"); 3209 3210 /* Preserve the last byte in cases where only part of it will be overwritten, 3211 * the multiply below may overflow, we don't care because ANSI-C guarantees 3212 * we get the low bits. 3213 */ 3214 end_mask = (pixel_depth * row_width) & 7; 3215 if (end_mask != 0) 3216 { 3217 /* end_ptr == NULL is a flag to say do nothing */ 3218 end_ptr = dp + PNG_ROWBYTES(pixel_depth, row_width) - 1; 3219 end_byte = *end_ptr; 3220 # ifdef PNG_READ_PACKSWAP_SUPPORTED 3221 if ((png_ptr->transformations & PNG_PACKSWAP) != 0) 3222 /* little-endian byte */ 3223 end_mask = (unsigned int)(0xff << end_mask); 3224 3225 else /* big-endian byte */ 3226 # endif 3227 end_mask = 0xff >> end_mask; 3228 /* end_mask is now the bits to *keep* from the destination row */ 3229 } 3230 3231 /* For non-interlaced images this reduces to a memcpy(). A memcpy() 3232 * will also happen if interlacing isn't supported or if the application 3233 * does not call png_set_interlace_handling(). In the latter cases the 3234 * caller just gets a sequence of the unexpanded rows from each interlace 3235 * pass. 3236 */ 3237 #ifdef PNG_READ_INTERLACING_SUPPORTED 3238 if (png_ptr->interlaced != 0 && 3239 (png_ptr->transformations & PNG_INTERLACE) != 0 && 3240 pass < 6 && (display == 0 || 3241 /* The following copies everything for 'display' on passes 0, 2 and 4. */ 3242 (display == 1 && (pass & 1) != 0))) 3243 { 3244 /* Narrow images may have no bits in a pass; the caller should handle 3245 * this, but this test is cheap: 3246 */ 3247 if (row_width <= PNG_PASS_START_COL(pass)) 3248 return; 3249 3250 if (pixel_depth < 8) 3251 { 3252 /* For pixel depths up to 4 bpp the 8-pixel mask can be expanded to fit 3253 * into 32 bits, then a single loop over the bytes using the four byte 3254 * values in the 32-bit mask can be used. For the 'display' option the 3255 * expanded mask may also not require any masking within a byte. To 3256 * make this work the PACKSWAP option must be taken into account - it 3257 * simply requires the pixels to be reversed in each byte. 3258 * 3259 * The 'regular' case requires a mask for each of the first 6 passes, 3260 * the 'display' case does a copy for the even passes in the range 3261 * 0..6. This has already been handled in the test above. 3262 * 3263 * The masks are arranged as four bytes with the first byte to use in 3264 * the lowest bits (little-endian) regardless of the order (PACKSWAP or 3265 * not) of the pixels in each byte. 3266 * 3267 * NOTE: the whole of this logic depends on the caller of this function 3268 * only calling it on rows appropriate to the pass. This function only 3269 * understands the 'x' logic; the 'y' logic is handled by the caller. 3270 * 3271 * The following defines allow generation of compile time constant bit 3272 * masks for each pixel depth and each possibility of swapped or not 3273 * swapped bytes. Pass 'p' is in the range 0..6; 'x', a pixel index, 3274 * is in the range 0..7; and the result is 1 if the pixel is to be 3275 * copied in the pass, 0 if not. 'S' is for the sparkle method, 'B' 3276 * for the block method. 3277 * 3278 * With some compilers a compile time expression of the general form: 3279 * 3280 * (shift >= 32) ? (a >> (shift-32)) : (b >> shift) 3281 * 3282 * Produces warnings with values of 'shift' in the range 33 to 63 3283 * because the right hand side of the ?: expression is evaluated by 3284 * the compiler even though it isn't used. Microsoft Visual C (various 3285 * versions) and the Intel C compiler are known to do this. To avoid 3286 * this the following macros are used in 1.5.6. This is a temporary 3287 * solution to avoid destabilizing the code during the release process. 3288 */ 3289 # if PNG_USE_COMPILE_TIME_MASKS 3290 # define PNG_LSR(x,s) ((x)>>((s) & 0x1f)) 3291 # define PNG_LSL(x,s) ((x)<<((s) & 0x1f)) 3292 # else 3293 # define PNG_LSR(x,s) ((x)>>(s)) 3294 # define PNG_LSL(x,s) ((x)<<(s)) 3295 # endif 3296 # define S_COPY(p,x) (((p)<4 ? PNG_LSR(0x80088822,(3-(p))*8+(7-(x))) :\ 3297 PNG_LSR(0xaa55ff00,(7-(p))*8+(7-(x)))) & 1) 3298 # define B_COPY(p,x) (((p)<4 ? PNG_LSR(0xff0fff33,(3-(p))*8+(7-(x))) :\ 3299 PNG_LSR(0xff55ff00,(7-(p))*8+(7-(x)))) & 1) 3300 3301 /* Return a mask for pass 'p' pixel 'x' at depth 'd'. The mask is 3302 * little endian - the first pixel is at bit 0 - however the extra 3303 * parameter 's' can be set to cause the mask position to be swapped 3304 * within each byte, to match the PNG format. This is done by XOR of 3305 * the shift with 7, 6 or 4 for bit depths 1, 2 and 4. 3306 */ 3307 # define PIXEL_MASK(p,x,d,s) \ 3308 (PNG_LSL(((PNG_LSL(1U,(d)))-1),(((x)*(d))^((s)?8-(d):0)))) 3309 3310 /* Hence generate the appropriate 'block' or 'sparkle' pixel copy mask. 3311 */ 3312 # define S_MASKx(p,x,d,s) (S_COPY(p,x)?PIXEL_MASK(p,x,d,s):0) 3313 # define B_MASKx(p,x,d,s) (B_COPY(p,x)?PIXEL_MASK(p,x,d,s):0) 3314 3315 /* Combine 8 of these to get the full mask. For the 1-bpp and 2-bpp 3316 * cases the result needs replicating, for the 4-bpp case the above 3317 * generates a full 32 bits. 3318 */ 3319 # define MASK_EXPAND(m,d) ((m)*((d)==1?0x01010101:((d)==2?0x00010001:1))) 3320 3321 # define S_MASK(p,d,s) MASK_EXPAND(S_MASKx(p,0,d,s) + S_MASKx(p,1,d,s) +\ 3322 S_MASKx(p,2,d,s) + S_MASKx(p,3,d,s) + S_MASKx(p,4,d,s) +\ 3323 S_MASKx(p,5,d,s) + S_MASKx(p,6,d,s) + S_MASKx(p,7,d,s), d) 3324 3325 # define B_MASK(p,d,s) MASK_EXPAND(B_MASKx(p,0,d,s) + B_MASKx(p,1,d,s) +\ 3326 B_MASKx(p,2,d,s) + B_MASKx(p,3,d,s) + B_MASKx(p,4,d,s) +\ 3327 B_MASKx(p,5,d,s) + B_MASKx(p,6,d,s) + B_MASKx(p,7,d,s), d) 3328 3329 #if PNG_USE_COMPILE_TIME_MASKS 3330 /* Utility macros to construct all the masks for a depth/swap 3331 * combination. The 's' parameter says whether the format is PNG 3332 * (big endian bytes) or not. Only the three odd-numbered passes are 3333 * required for the display/block algorithm. 3334 */ 3335 # define S_MASKS(d,s) { S_MASK(0,d,s), S_MASK(1,d,s), S_MASK(2,d,s),\ 3336 S_MASK(3,d,s), S_MASK(4,d,s), S_MASK(5,d,s) } 3337 3338 # define B_MASKS(d,s) { B_MASK(1,d,s), B_MASK(3,d,s), B_MASK(5,d,s) } 3339 3340 # define DEPTH_INDEX(d) ((d)==1?0:((d)==2?1:2)) 3341 3342 /* Hence the pre-compiled masks indexed by PACKSWAP (or not), depth and 3343 * then pass: 3344 */ 3345 static PNG_CONST png_uint_32 row_mask[2/*PACKSWAP*/][3/*depth*/][6] = 3346 { 3347 /* Little-endian byte masks for PACKSWAP */ 3348 { S_MASKS(1,0), S_MASKS(2,0), S_MASKS(4,0) }, 3349 /* Normal (big-endian byte) masks - PNG format */ 3350 { S_MASKS(1,1), S_MASKS(2,1), S_MASKS(4,1) } 3351 }; 3352 3353 /* display_mask has only three entries for the odd passes, so index by 3354 * pass>>1. 3355 */ 3356 static PNG_CONST png_uint_32 display_mask[2][3][3] = 3357 { 3358 /* Little-endian byte masks for PACKSWAP */ 3359 { B_MASKS(1,0), B_MASKS(2,0), B_MASKS(4,0) }, 3360 /* Normal (big-endian byte) masks - PNG format */ 3361 { B_MASKS(1,1), B_MASKS(2,1), B_MASKS(4,1) } 3362 }; 3363 3364 # define MASK(pass,depth,display,png)\ 3365 ((display)?display_mask[png][DEPTH_INDEX(depth)][pass>>1]:\ 3366 row_mask[png][DEPTH_INDEX(depth)][pass]) 3367 3368 #else /* !PNG_USE_COMPILE_TIME_MASKS */ 3369 /* This is the runtime alternative: it seems unlikely that this will 3370 * ever be either smaller or faster than the compile time approach. 3371 */ 3372 # define MASK(pass,depth,display,png)\ 3373 ((display)?B_MASK(pass,depth,png):S_MASK(pass,depth,png)) 3374 #endif /* !USE_COMPILE_TIME_MASKS */ 3375 3376 /* Use the appropriate mask to copy the required bits. In some cases 3377 * the byte mask will be 0 or 0xff; optimize these cases. row_width is 3378 * the number of pixels, but the code copies bytes, so it is necessary 3379 * to special case the end. 3380 */ 3381 png_uint_32 pixels_per_byte = 8 / pixel_depth; 3382 png_uint_32 mask; 3383 3384 # ifdef PNG_READ_PACKSWAP_SUPPORTED 3385 if ((png_ptr->transformations & PNG_PACKSWAP) != 0) 3386 mask = MASK(pass, pixel_depth, display, 0); 3387 3388 else 3389 # endif 3390 mask = MASK(pass, pixel_depth, display, 1); 3391 3392 for (;;) 3393 { 3394 png_uint_32 m; 3395 3396 /* It doesn't matter in the following if png_uint_32 has more than 3397 * 32 bits because the high bits always match those in m<<24; it is, 3398 * however, essential to use OR here, not +, because of this. 3399 */ 3400 m = mask; 3401 mask = (m >> 8) | (m << 24); /* rotate right to good compilers */ 3402 m &= 0xff; 3403 3404 if (m != 0) /* something to copy */ 3405 { 3406 if (m != 0xff) 3407 *dp = (png_byte)((*dp & ~m) | (*sp & m)); 3408 else 3409 *dp = *sp; 3410 } 3411 3412 /* NOTE: this may overwrite the last byte with garbage if the image 3413 * is not an exact number of bytes wide; libpng has always done 3414 * this. 3415 */ 3416 if (row_width <= pixels_per_byte) 3417 break; /* May need to restore part of the last byte */ 3418 3419 row_width -= pixels_per_byte; 3420 ++dp; 3421 ++sp; 3422 } 3423 } 3424 3425 else /* pixel_depth >= 8 */ 3426 { 3427 unsigned int bytes_to_copy, bytes_to_jump; 3428 3429 /* Validate the depth - it must be a multiple of 8 */ 3430 if (pixel_depth & 7) 3431 png_error(png_ptr, "invalid user transform pixel depth"); 3432 3433 pixel_depth >>= 3; /* now in bytes */ 3434 row_width *= pixel_depth; 3435 3436 /* Regardless of pass number the Adam 7 interlace always results in a 3437 * fixed number of pixels to copy then to skip. There may be a 3438 * different number of pixels to skip at the start though. 3439 */ 3440 { 3441 unsigned int offset = PNG_PASS_START_COL(pass) * pixel_depth; 3442 3443 row_width -= offset; 3444 dp += offset; 3445 sp += offset; 3446 } 3447 3448 /* Work out the bytes to copy. */ 3449 if (display != 0) 3450 { 3451 /* When doing the 'block' algorithm the pixel in the pass gets 3452 * replicated to adjacent pixels. This is why the even (0,2,4,6) 3453 * passes are skipped above - the entire expanded row is copied. 3454 */ 3455 bytes_to_copy = (1<<((6-pass)>>1)) * pixel_depth; 3456 3457 /* But don't allow this number to exceed the actual row width. */ 3458 if (bytes_to_copy > row_width) 3459 bytes_to_copy = (unsigned int)/*SAFE*/row_width; 3460 } 3461 3462 else /* normal row; Adam7 only ever gives us one pixel to copy. */ 3463 bytes_to_copy = pixel_depth; 3464 3465 /* In Adam7 there is a constant offset between where the pixels go. */ 3466 bytes_to_jump = PNG_PASS_COL_OFFSET(pass) * pixel_depth; 3467 3468 /* And simply copy these bytes. Some optimization is possible here, 3469 * depending on the value of 'bytes_to_copy'. Special case the low 3470 * byte counts, which we know to be frequent. 3471 * 3472 * Notice that these cases all 'return' rather than 'break' - this 3473 * avoids an unnecessary test on whether to restore the last byte 3474 * below. 3475 */ 3476 switch (bytes_to_copy) 3477 { 3478 case 1: 3479 for (;;) 3480 { 3481 *dp = *sp; 3482 3483 if (row_width <= bytes_to_jump) 3484 return; 3485 3486 dp += bytes_to_jump; 3487 sp += bytes_to_jump; 3488 row_width -= bytes_to_jump; 3489 } 3490 3491 case 2: 3492 /* There is a possibility of a partial copy at the end here; this 3493 * slows the code down somewhat. 3494 */ 3495 do 3496 { 3497 dp[0] = sp[0]; dp[1] = sp[1]; 3498 3499 if (row_width <= bytes_to_jump) 3500 return; 3501 3502 sp += bytes_to_jump; 3503 dp += bytes_to_jump; 3504 row_width -= bytes_to_jump; 3505 } 3506 while (row_width > 1); 3507 3508 /* And there can only be one byte left at this point: */ 3509 *dp = *sp; 3510 return; 3511 3512 case 3: 3513 /* This can only be the RGB case, so each copy is exactly one 3514 * pixel and it is not necessary to check for a partial copy. 3515 */ 3516 for (;;) 3517 { 3518 dp[0] = sp[0]; dp[1] = sp[1]; dp[2] = sp[2]; 3519 3520 if (row_width <= bytes_to_jump) 3521 return; 3522 3523 sp += bytes_to_jump; 3524 dp += bytes_to_jump; 3525 row_width -= bytes_to_jump; 3526 } 3527 3528 default: 3529 #if PNG_ALIGN_TYPE != PNG_ALIGN_NONE 3530 /* Check for double byte alignment and, if possible, use a 3531 * 16-bit copy. Don't attempt this for narrow images - ones that 3532 * are less than an interlace panel wide. Don't attempt it for 3533 * wide bytes_to_copy either - use the memcpy there. 3534 */ 3535 if (bytes_to_copy < 16 /*else use memcpy*/ && 3536 png_isaligned(dp, png_uint_16) && 3537 png_isaligned(sp, png_uint_16) && 3538 bytes_to_copy % (sizeof (png_uint_16)) == 0 && 3539 bytes_to_jump % (sizeof (png_uint_16)) == 0) 3540 { 3541 /* Everything is aligned for png_uint_16 copies, but try for 3542 * png_uint_32 first. 3543 */ 3544 if (png_isaligned(dp, png_uint_32) && 3545 png_isaligned(sp, png_uint_32) && 3546 bytes_to_copy % (sizeof (png_uint_32)) == 0 && 3547 bytes_to_jump % (sizeof (png_uint_32)) == 0) 3548 { 3549 png_uint_32p dp32 = png_aligncast(png_uint_32p,dp); 3550 png_const_uint_32p sp32 = png_aligncastconst( 3551 png_const_uint_32p, sp); 3552 size_t skip = (bytes_to_jump-bytes_to_copy) / 3553 (sizeof (png_uint_32)); 3554 3555 do 3556 { 3557 size_t c = bytes_to_copy; 3558 do 3559 { 3560 *dp32++ = *sp32++; 3561 c -= (sizeof (png_uint_32)); 3562 } 3563 while (c > 0); 3564 3565 if (row_width <= bytes_to_jump) 3566 return; 3567 3568 dp32 += skip; 3569 sp32 += skip; 3570 row_width -= bytes_to_jump; 3571 } 3572 while (bytes_to_copy <= row_width); 3573 3574 /* Get to here when the row_width truncates the final copy. 3575 * There will be 1-3 bytes left to copy, so don't try the 3576 * 16-bit loop below. 3577 */ 3578 dp = (png_bytep)dp32; 3579 sp = (png_const_bytep)sp32; 3580 do 3581 *dp++ = *sp++; 3582 while (--row_width > 0); 3583 return; 3584 } 3585 3586 /* Else do it in 16-bit quantities, but only if the size is 3587 * not too large. 3588 */ 3589 else 3590 { 3591 png_uint_16p dp16 = png_aligncast(png_uint_16p, dp); 3592 png_const_uint_16p sp16 = png_aligncastconst( 3593 png_const_uint_16p, sp); 3594 size_t skip = (bytes_to_jump-bytes_to_copy) / 3595 (sizeof (png_uint_16)); 3596 3597 do 3598 { 3599 size_t c = bytes_to_copy; 3600 do 3601 { 3602 *dp16++ = *sp16++; 3603 c -= (sizeof (png_uint_16)); 3604 } 3605 while (c > 0); 3606 3607 if (row_width <= bytes_to_jump) 3608 return; 3609 3610 dp16 += skip; 3611 sp16 += skip; 3612 row_width -= bytes_to_jump; 3613 } 3614 while (bytes_to_copy <= row_width); 3615 3616 /* End of row - 1 byte left, bytes_to_copy > row_width: */ 3617 dp = (png_bytep)dp16; 3618 sp = (png_const_bytep)sp16; 3619 do 3620 *dp++ = *sp++; 3621 while (--row_width > 0); 3622 return; 3623 } 3624 } 3625 #endif /* ALIGN_TYPE code */ 3626 3627 /* The true default - use a memcpy: */ 3628 for (;;) 3629 { 3630 memcpy(dp, sp, bytes_to_copy); 3631 3632 if (row_width <= bytes_to_jump) 3633 return; 3634 3635 sp += bytes_to_jump; 3636 dp += bytes_to_jump; 3637 row_width -= bytes_to_jump; 3638 if (bytes_to_copy > row_width) 3639 bytes_to_copy = (unsigned int)/*SAFE*/row_width; 3640 } 3641 } 3642 3643 /* NOT REACHED*/ 3644 } /* pixel_depth >= 8 */ 3645 3646 /* Here if pixel_depth < 8 to check 'end_ptr' below. */ 3647 } 3648 else 3649 #endif /* READ_INTERLACING */ 3650 3651 /* If here then the switch above wasn't used so just memcpy the whole row 3652 * from the temporary row buffer (notice that this overwrites the end of the 3653 * destination row if it is a partial byte.) 3654 */ 3655 memcpy(dp, sp, PNG_ROWBYTES(pixel_depth, row_width)); 3656 3657 /* Restore the overwritten bits from the last byte if necessary. */ 3658 if (end_ptr != NULL) 3659 *end_ptr = (png_byte)((end_byte & end_mask) | (*end_ptr & ~end_mask)); 3660 } 3661 3662 #ifdef PNG_READ_INTERLACING_SUPPORTED 3663 void /* PRIVATE */ 3664 png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass, 3665 png_uint_32 transformations /* Because these may affect the byte layout */) 3666 { 3667 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ 3668 /* Offset to next interlace block */ 3669 static PNG_CONST unsigned int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1}; 3670 3671 png_debug(1, "in png_do_read_interlace"); 3672 if (row != NULL && row_info != NULL) 3673 { 3674 png_uint_32 final_width; 3675 3676 final_width = row_info->width * png_pass_inc[pass]; 3677 3678 switch (row_info->pixel_depth) 3679 { 3680 case 1: 3681 { 3682 png_bytep sp = row + (png_size_t)((row_info->width - 1) >> 3); 3683 png_bytep dp = row + (png_size_t)((final_width - 1) >> 3); 3684 unsigned int sshift, dshift; 3685 unsigned int s_start, s_end; 3686 int s_inc; 3687 int jstop = (int)png_pass_inc[pass]; 3688 png_byte v; 3689 png_uint_32 i; 3690 int j; 3691 3692 #ifdef PNG_READ_PACKSWAP_SUPPORTED 3693 if ((transformations & PNG_PACKSWAP) != 0) 3694 { 3695 sshift = ((row_info->width + 7) & 0x07); 3696 dshift = ((final_width + 7) & 0x07); 3697 s_start = 7; 3698 s_end = 0; 3699 s_inc = -1; 3700 } 3701 3702 else 3703 #endif 3704 { 3705 sshift = 7 - ((row_info->width + 7) & 0x07); 3706 dshift = 7 - ((final_width + 7) & 0x07); 3707 s_start = 0; 3708 s_end = 7; 3709 s_inc = 1; 3710 } 3711 3712 for (i = 0; i < row_info->width; i++) 3713 { 3714 v = (png_byte)((*sp >> sshift) & 0x01); 3715 for (j = 0; j < jstop; j++) 3716 { 3717 unsigned int tmp = *dp & (0x7f7f >> (7 - dshift)); 3718 tmp |= (unsigned int)(v << dshift); 3719 *dp = (png_byte)(tmp & 0xff); 3720 3721 if (dshift == s_end) 3722 { 3723 dshift = s_start; 3724 dp--; 3725 } 3726 3727 else 3728 dshift = (unsigned int)((int)dshift + s_inc); 3729 } 3730 3731 if (sshift == s_end) 3732 { 3733 sshift = s_start; 3734 sp--; 3735 } 3736 3737 else 3738 sshift = (unsigned int)((int)sshift + s_inc); 3739 } 3740 break; 3741 } 3742 3743 case 2: 3744 { 3745 png_bytep sp = row + (png_uint_32)((row_info->width - 1) >> 2); 3746 png_bytep dp = row + (png_uint_32)((final_width - 1) >> 2); 3747 unsigned int sshift, dshift; 3748 unsigned int s_start, s_end; 3749 int s_inc; 3750 int jstop = (int)png_pass_inc[pass]; 3751 png_uint_32 i; 3752 3753 #ifdef PNG_READ_PACKSWAP_SUPPORTED 3754 if ((transformations & PNG_PACKSWAP) != 0) 3755 { 3756 sshift = (((row_info->width + 3) & 0x03) << 1); 3757 dshift = (((final_width + 3) & 0x03) << 1); 3758 s_start = 6; 3759 s_end = 0; 3760 s_inc = -2; 3761 } 3762 3763 else 3764 #endif 3765 { 3766 sshift = ((3 - ((row_info->width + 3) & 0x03)) << 1); 3767 dshift = ((3 - ((final_width + 3) & 0x03)) << 1); 3768 s_start = 0; 3769 s_end = 6; 3770 s_inc = 2; 3771 } 3772 3773 for (i = 0; i < row_info->width; i++) 3774 { 3775 png_byte v; 3776 int j; 3777 3778 v = (png_byte)((*sp >> sshift) & 0x03); 3779 for (j = 0; j < jstop; j++) 3780 { 3781 unsigned int tmp = *dp & (0x3f3f >> (6 - dshift)); 3782 tmp |= (unsigned int)(v << dshift); 3783 *dp = (png_byte)(tmp & 0xff); 3784 3785 if (dshift == s_end) 3786 { 3787 dshift = s_start; 3788 dp--; 3789 } 3790 3791 else 3792 dshift = (unsigned int)((int)dshift + s_inc); 3793 } 3794 3795 if (sshift == s_end) 3796 { 3797 sshift = s_start; 3798 sp--; 3799 } 3800 3801 else 3802 sshift = (unsigned int)((int)sshift + s_inc); 3803 } 3804 break; 3805 } 3806 3807 case 4: 3808 { 3809 png_bytep sp = row + (png_size_t)((row_info->width - 1) >> 1); 3810 png_bytep dp = row + (png_size_t)((final_width - 1) >> 1); 3811 unsigned int sshift, dshift; 3812 unsigned int s_start, s_end; 3813 int s_inc; 3814 png_uint_32 i; 3815 int jstop = (int)png_pass_inc[pass]; 3816 3817 #ifdef PNG_READ_PACKSWAP_SUPPORTED 3818 if ((transformations & PNG_PACKSWAP) != 0) 3819 { 3820 sshift = (((row_info->width + 1) & 0x01) << 2); 3821 dshift = (((final_width + 1) & 0x01) << 2); 3822 s_start = 4; 3823 s_end = 0; 3824 s_inc = -4; 3825 } 3826 3827 else 3828 #endif 3829 { 3830 sshift = ((1 - ((row_info->width + 1) & 0x01)) << 2); 3831 dshift = ((1 - ((final_width + 1) & 0x01)) << 2); 3832 s_start = 0; 3833 s_end = 4; 3834 s_inc = 4; 3835 } 3836 3837 for (i = 0; i < row_info->width; i++) 3838 { 3839 png_byte v = (png_byte)((*sp >> sshift) & 0x0f); 3840 int j; 3841 3842 for (j = 0; j < jstop; j++) 3843 { 3844 unsigned int tmp = *dp & (0xf0f >> (4 - dshift)); 3845 tmp |= (unsigned int)(v << dshift); 3846 *dp = (png_byte)(tmp & 0xff); 3847 3848 if (dshift == s_end) 3849 { 3850 dshift = s_start; 3851 dp--; 3852 } 3853 3854 else 3855 dshift = (unsigned int)((int)dshift + s_inc); 3856 } 3857 3858 if (sshift == s_end) 3859 { 3860 sshift = s_start; 3861 sp--; 3862 } 3863 3864 else 3865 sshift = (unsigned int)((int)sshift + s_inc); 3866 } 3867 break; 3868 } 3869 3870 default: 3871 { 3872 png_size_t pixel_bytes = (row_info->pixel_depth >> 3); 3873 3874 png_bytep sp = row + (png_size_t)(row_info->width - 1) 3875 * pixel_bytes; 3876 3877 png_bytep dp = row + (png_size_t)(final_width - 1) * pixel_bytes; 3878 3879 int jstop = (int)png_pass_inc[pass]; 3880 png_uint_32 i; 3881 3882 for (i = 0; i < row_info->width; i++) 3883 { 3884 png_byte v[8]; /* SAFE; pixel_depth does not exceed 64 */ 3885 int j; 3886 3887 memcpy(v, sp, pixel_bytes); 3888 3889 for (j = 0; j < jstop; j++) 3890 { 3891 memcpy(dp, v, pixel_bytes); 3892 dp -= pixel_bytes; 3893 } 3894 3895 sp -= pixel_bytes; 3896 } 3897 break; 3898 } 3899 } 3900 3901 row_info->width = final_width; 3902 row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, final_width); 3903 } 3904 #ifndef PNG_READ_PACKSWAP_SUPPORTED 3905 PNG_UNUSED(transformations) /* Silence compiler warning */ 3906 #endif 3907 } 3908 #endif /* READ_INTERLACING */ 3909 3910 static void 3911 png_read_filter_row_sub(png_row_infop row_info, png_bytep row, 3912 png_const_bytep prev_row) 3913 { 3914 png_size_t i; 3915 png_size_t istop = row_info->rowbytes; 3916 unsigned int bpp = (row_info->pixel_depth + 7) >> 3; 3917 png_bytep rp = row + bpp; 3918 3919 PNG_UNUSED(prev_row) 3920 3921 for (i = bpp; i < istop; i++) 3922 { 3923 *rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 0xff); 3924 rp++; 3925 } 3926 } 3927 3928 static void 3929 png_read_filter_row_up(png_row_infop row_info, png_bytep row, 3930 png_const_bytep prev_row) 3931 { 3932 png_size_t i; 3933 png_size_t istop = row_info->rowbytes; 3934 png_bytep rp = row; 3935 png_const_bytep pp = prev_row; 3936 3937 for (i = 0; i < istop; i++) 3938 { 3939 *rp = (png_byte)(((int)(*rp) + (int)(*pp++)) & 0xff); 3940 rp++; 3941 } 3942 } 3943 3944 static void 3945 png_read_filter_row_avg(png_row_infop row_info, png_bytep row, 3946 png_const_bytep prev_row) 3947 { 3948 png_size_t i; 3949 png_bytep rp = row; 3950 png_const_bytep pp = prev_row; 3951 unsigned int bpp = (row_info->pixel_depth + 7) >> 3; 3952 png_size_t istop = row_info->rowbytes - bpp; 3953 3954 for (i = 0; i < bpp; i++) 3955 { 3956 *rp = (png_byte)(((int)(*rp) + 3957 ((int)(*pp++) / 2 )) & 0xff); 3958 3959 rp++; 3960 } 3961 3962 for (i = 0; i < istop; i++) 3963 { 3964 *rp = (png_byte)(((int)(*rp) + 3965 (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff); 3966 3967 rp++; 3968 } 3969 } 3970 3971 static void 3972 png_read_filter_row_paeth_1byte_pixel(png_row_infop row_info, png_bytep row, 3973 png_const_bytep prev_row) 3974 { 3975 png_bytep rp_end = row + row_info->rowbytes; 3976 int a, c; 3977 3978 /* First pixel/byte */ 3979 c = *prev_row++; 3980 a = *row + c; 3981 *row++ = (png_byte)a; 3982 3983 /* Remainder */ 3984 while (row < rp_end) 3985 { 3986 int b, pa, pb, pc, p; 3987 3988 a &= 0xff; /* From previous iteration or start */ 3989 b = *prev_row++; 3990 3991 p = b - c; 3992 pc = a - c; 3993 3994 #ifdef PNG_USE_ABS 3995 pa = abs(p); 3996 pb = abs(pc); 3997 pc = abs(p + pc); 3998 #else 3999 pa = p < 0 ? -p : p; 4000 pb = pc < 0 ? -pc : pc; 4001 pc = (p + pc) < 0 ? -(p + pc) : p + pc; 4002 #endif 4003 4004 /* Find the best predictor, the least of pa, pb, pc favoring the earlier 4005 * ones in the case of a tie. 4006 */ 4007 if (pb < pa) 4008 { 4009 pa = pb; a = b; 4010 } 4011 if (pc < pa) a = c; 4012 4013 /* Calculate the current pixel in a, and move the previous row pixel to c 4014 * for the next time round the loop 4015 */ 4016 c = b; 4017 a += *row; 4018 *row++ = (png_byte)a; 4019 } 4020 } 4021 4022 static void 4023 png_read_filter_row_paeth_multibyte_pixel(png_row_infop row_info, png_bytep row, 4024 png_const_bytep prev_row) 4025 { 4026 unsigned int bpp = (row_info->pixel_depth + 7) >> 3; 4027 png_bytep rp_end = row + bpp; 4028 4029 /* Process the first pixel in the row completely (this is the same as 'up' 4030 * because there is only one candidate predictor for the first row). 4031 */ 4032 while (row < rp_end) 4033 { 4034 int a = *row + *prev_row++; 4035 *row++ = (png_byte)a; 4036 } 4037 4038 /* Remainder */ 4039 rp_end = rp_end + (row_info->rowbytes - bpp); 4040 4041 while (row < rp_end) 4042 { 4043 int a, b, c, pa, pb, pc, p; 4044 4045 c = *(prev_row - bpp); 4046 a = *(row - bpp); 4047 b = *prev_row++; 4048 4049 p = b - c; 4050 pc = a - c; 4051 4052 #ifdef PNG_USE_ABS 4053 pa = abs(p); 4054 pb = abs(pc); 4055 pc = abs(p + pc); 4056 #else 4057 pa = p < 0 ? -p : p; 4058 pb = pc < 0 ? -pc : pc; 4059 pc = (p + pc) < 0 ? -(p + pc) : p + pc; 4060 #endif 4061 4062 if (pb < pa) 4063 { 4064 pa = pb; a = b; 4065 } 4066 if (pc < pa) a = c; 4067 4068 a += *row; 4069 *row++ = (png_byte)a; 4070 } 4071 } 4072 4073 static void 4074 png_init_filter_functions(png_structrp pp) 4075 /* This function is called once for every PNG image (except for PNG images 4076 * that only use PNG_FILTER_VALUE_NONE for all rows) to set the 4077 * implementations required to reverse the filtering of PNG rows. Reversing 4078 * the filter is the first transformation performed on the row data. It is 4079 * performed in place, therefore an implementation can be selected based on 4080 * the image pixel format. If the implementation depends on image width then 4081 * take care to ensure that it works correctly if the image is interlaced - 4082 * interlacing causes the actual row width to vary. 4083 */ 4084 { 4085 unsigned int bpp = (pp->pixel_depth + 7) >> 3; 4086 4087 pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub; 4088 pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up; 4089 pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg; 4090 if (bpp == 1) 4091 pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = 4092 png_read_filter_row_paeth_1byte_pixel; 4093 else 4094 pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = 4095 png_read_filter_row_paeth_multibyte_pixel; 4096 4097 #ifdef PNG_FILTER_OPTIMIZATIONS 4098 /* To use this define PNG_FILTER_OPTIMIZATIONS as the name of a function to 4099 * call to install hardware optimizations for the above functions; simply 4100 * replace whatever elements of the pp->read_filter[] array with a hardware 4101 * specific (or, for that matter, generic) optimization. 4102 * 4103 * To see an example of this examine what configure.ac does when 4104 * --enable-arm-neon is specified on the command line. 4105 */ 4106 PNG_FILTER_OPTIMIZATIONS(pp, bpp); 4107 #endif 4108 } 4109 4110 void /* PRIVATE */ 4111 png_read_filter_row(png_structrp pp, png_row_infop row_info, png_bytep row, 4112 png_const_bytep prev_row, int filter) 4113 { 4114 /* OPTIMIZATION: DO NOT MODIFY THIS FUNCTION, instead #define 4115 * PNG_FILTER_OPTIMIZATIONS to a function that overrides the generic 4116 * implementations. See png_init_filter_functions above. 4117 */ 4118 if (filter > PNG_FILTER_VALUE_NONE && filter < PNG_FILTER_VALUE_LAST) 4119 { 4120 if (pp->read_filter[0] == NULL) 4121 png_init_filter_functions(pp); 4122 4123 pp->read_filter[filter-1](row_info, row, prev_row); 4124 } 4125 } 4126 4127 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED 4128 void /* PRIVATE */ 4129 png_read_IDAT_data(png_structrp png_ptr, png_bytep output, 4130 png_alloc_size_t avail_out) 4131 { 4132 /* Loop reading IDATs and decompressing the result into output[avail_out] */ 4133 png_ptr->zstream.next_out = output; 4134 png_ptr->zstream.avail_out = 0; /* safety: set below */ 4135 4136 if (output == NULL) 4137 avail_out = 0; 4138 4139 do 4140 { 4141 int ret; 4142 png_byte tmpbuf[PNG_INFLATE_BUF_SIZE]; 4143 4144 if (png_ptr->zstream.avail_in == 0) 4145 { 4146 uInt avail_in; 4147 png_bytep buffer; 4148 4149 while (png_ptr->idat_size == 0) 4150 { 4151 png_crc_finish(png_ptr, 0); 4152 4153 png_ptr->idat_size = png_read_chunk_header(png_ptr); 4154 /* This is an error even in the 'check' case because the code just 4155 * consumed a non-IDAT header. 4156 */ 4157 if (png_ptr->chunk_name != png_IDAT) 4158 png_error(png_ptr, "Not enough image data"); 4159 } 4160 4161 avail_in = png_ptr->IDAT_read_size; 4162 4163 if (avail_in > png_ptr->idat_size) 4164 avail_in = (uInt)png_ptr->idat_size; 4165 4166 /* A PNG with a gradually increasing IDAT size will defeat this attempt 4167 * to minimize memory usage by causing lots of re-allocs, but 4168 * realistically doing IDAT_read_size re-allocs is not likely to be a 4169 * big problem. 4170 */ 4171 buffer = png_read_buffer(png_ptr, avail_in, 0/*error*/); 4172 4173 png_crc_read(png_ptr, buffer, avail_in); 4174 png_ptr->idat_size -= avail_in; 4175 4176 png_ptr->zstream.next_in = buffer; 4177 png_ptr->zstream.avail_in = avail_in; 4178 } 4179 4180 /* And set up the output side. */ 4181 if (output != NULL) /* standard read */ 4182 { 4183 uInt out = ZLIB_IO_MAX; 4184 4185 if (out > avail_out) 4186 out = (uInt)avail_out; 4187 4188 avail_out -= out; 4189 png_ptr->zstream.avail_out = out; 4190 } 4191 4192 else /* after last row, checking for end */ 4193 { 4194 png_ptr->zstream.next_out = tmpbuf; 4195 png_ptr->zstream.avail_out = (sizeof tmpbuf); 4196 } 4197 4198 /* Use NO_FLUSH; this gives zlib the maximum opportunity to optimize the 4199 * process. If the LZ stream is truncated the sequential reader will 4200 * terminally damage the stream, above, by reading the chunk header of the 4201 * following chunk (it then exits with png_error). 4202 * 4203 * TODO: deal more elegantly with truncated IDAT lists. 4204 */ 4205 ret = PNG_INFLATE(png_ptr, Z_NO_FLUSH); 4206 4207 /* Take the unconsumed output back. */ 4208 if (output != NULL) 4209 avail_out += png_ptr->zstream.avail_out; 4210 4211 else /* avail_out counts the extra bytes */ 4212 avail_out += (sizeof tmpbuf) - png_ptr->zstream.avail_out; 4213 4214 png_ptr->zstream.avail_out = 0; 4215 4216 if (ret == Z_STREAM_END) 4217 { 4218 /* Do this for safety; we won't read any more into this row. */ 4219 png_ptr->zstream.next_out = NULL; 4220 4221 png_ptr->mode |= PNG_AFTER_IDAT; 4222 png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED; 4223 4224 if (png_ptr->zstream.avail_in > 0 || png_ptr->idat_size > 0) 4225 png_chunk_benign_error(png_ptr, "Extra compressed data"); 4226 break; 4227 } 4228 4229 if (ret != Z_OK) 4230 { 4231 png_zstream_error(png_ptr, ret); 4232 4233 if (output != NULL) 4234 png_chunk_error(png_ptr, png_ptr->zstream.msg); 4235 4236 else /* checking */ 4237 { 4238 png_chunk_benign_error(png_ptr, png_ptr->zstream.msg); 4239 return; 4240 } 4241 } 4242 } while (avail_out > 0); 4243 4244 if (avail_out > 0) 4245 { 4246 /* The stream ended before the image; this is the same as too few IDATs so 4247 * should be handled the same way. 4248 */ 4249 if (output != NULL) 4250 png_error(png_ptr, "Not enough image data"); 4251 4252 else /* the deflate stream contained extra data */ 4253 png_chunk_benign_error(png_ptr, "Too much image data"); 4254 } 4255 } 4256 4257 void /* PRIVATE */ 4258 png_read_finish_IDAT(png_structrp png_ptr) 4259 { 4260 /* We don't need any more data and the stream should have ended, however the 4261 * LZ end code may actually not have been processed. In this case we must 4262 * read it otherwise stray unread IDAT data or, more likely, an IDAT chunk 4263 * may still remain to be consumed. 4264 */ 4265 if ((png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0) 4266 { 4267 /* The NULL causes png_read_IDAT_data to swallow any remaining bytes in 4268 * the compressed stream, but the stream may be damaged too, so even after 4269 * this call we may need to terminate the zstream ownership. 4270 */ 4271 png_read_IDAT_data(png_ptr, NULL, 0); 4272 png_ptr->zstream.next_out = NULL; /* safety */ 4273 4274 /* Now clear everything out for safety; the following may not have been 4275 * done. 4276 */ 4277 if ((png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0) 4278 { 4279 png_ptr->mode |= PNG_AFTER_IDAT; 4280 png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED; 4281 } 4282 } 4283 4284 /* If the zstream has not been released do it now *and* terminate the reading 4285 * of the final IDAT chunk. 4286 */ 4287 if (png_ptr->zowner == png_IDAT) 4288 { 4289 /* Always do this; the pointers otherwise point into the read buffer. */ 4290 png_ptr->zstream.next_in = NULL; 4291 png_ptr->zstream.avail_in = 0; 4292 4293 /* Now we no longer own the zstream. */ 4294 png_ptr->zowner = 0; 4295 4296 /* The slightly weird semantics of the sequential IDAT reading is that we 4297 * are always in or at the end of an IDAT chunk, so we always need to do a 4298 * crc_finish here. If idat_size is non-zero we also need to read the 4299 * spurious bytes at the end of the chunk now. 4300 */ 4301 (void)png_crc_finish(png_ptr, png_ptr->idat_size); 4302 } 4303 } 4304 4305 void /* PRIVATE */ 4306 png_read_finish_row(png_structrp png_ptr) 4307 { 4308 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ 4309 4310 /* Start of interlace block */ 4311 static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0}; 4312 4313 /* Offset to next interlace block */ 4314 static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1}; 4315 4316 /* Start of interlace block in the y direction */ 4317 static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1}; 4318 4319 /* Offset to next interlace block in the y direction */ 4320 static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2}; 4321 4322 png_debug(1, "in png_read_finish_row"); 4323 png_ptr->row_number++; 4324 if (png_ptr->row_number < png_ptr->num_rows) 4325 return; 4326 4327 if (png_ptr->interlaced != 0) 4328 { 4329 png_ptr->row_number = 0; 4330 4331 /* TO DO: don't do this if prev_row isn't needed (requires 4332 * read-ahead of the next row's filter byte. 4333 */ 4334 memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1); 4335 4336 do 4337 { 4338 png_ptr->pass++; 4339 4340 if (png_ptr->pass >= 7) 4341 break; 4342 4343 png_ptr->iwidth = (png_ptr->width + 4344 png_pass_inc[png_ptr->pass] - 1 - 4345 png_pass_start[png_ptr->pass]) / 4346 png_pass_inc[png_ptr->pass]; 4347 4348 if ((png_ptr->transformations & PNG_INTERLACE) == 0) 4349 { 4350 png_ptr->num_rows = (png_ptr->height + 4351 png_pass_yinc[png_ptr->pass] - 1 - 4352 png_pass_ystart[png_ptr->pass]) / 4353 png_pass_yinc[png_ptr->pass]; 4354 } 4355 4356 else /* if (png_ptr->transformations & PNG_INTERLACE) */ 4357 break; /* libpng deinterlacing sees every row */ 4358 4359 } while (png_ptr->num_rows == 0 || png_ptr->iwidth == 0); 4360 4361 if (png_ptr->pass < 7) 4362 return; 4363 } 4364 4365 /* Here after at the end of the last row of the last pass. */ 4366 png_read_finish_IDAT(png_ptr); 4367 } 4368 #endif /* SEQUENTIAL_READ */ 4369 4370 void /* PRIVATE */ 4371 png_read_start_row(png_structrp png_ptr) 4372 { 4373 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ 4374 4375 /* Start of interlace block */ 4376 static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0}; 4377 4378 /* Offset to next interlace block */ 4379 static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1}; 4380 4381 /* Start of interlace block in the y direction */ 4382 static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1}; 4383 4384 /* Offset to next interlace block in the y direction */ 4385 static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2}; 4386 4387 unsigned int max_pixel_depth; 4388 png_size_t row_bytes; 4389 4390 png_debug(1, "in png_read_start_row"); 4391 4392 #ifdef PNG_READ_TRANSFORMS_SUPPORTED 4393 png_init_read_transformations(png_ptr); 4394 #endif 4395 if (png_ptr->interlaced != 0) 4396 { 4397 if ((png_ptr->transformations & PNG_INTERLACE) == 0) 4398 png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 - 4399 png_pass_ystart[0]) / png_pass_yinc[0]; 4400 4401 else 4402 png_ptr->num_rows = png_ptr->height; 4403 4404 png_ptr->iwidth = (png_ptr->width + 4405 png_pass_inc[png_ptr->pass] - 1 - 4406 png_pass_start[png_ptr->pass]) / 4407 png_pass_inc[png_ptr->pass]; 4408 } 4409 4410 else 4411 { 4412 png_ptr->num_rows = png_ptr->height; 4413 png_ptr->iwidth = png_ptr->width; 4414 } 4415 4416 max_pixel_depth = (unsigned int)png_ptr->pixel_depth; 4417 4418 /* WARNING: * png_read_transform_info (pngrtran.c) performs a simpler set of 4419 * calculations to calculate the final pixel depth, then 4420 * png_do_read_transforms actually does the transforms. This means that the 4421 * code which effectively calculates this value is actually repeated in three 4422 * separate places. They must all match. Innocent changes to the order of 4423 * transformations can and will break libpng in a way that causes memory 4424 * overwrites. 4425 * 4426 * TODO: fix this. 4427 */ 4428 #ifdef PNG_READ_PACK_SUPPORTED 4429 if ((png_ptr->transformations & PNG_PACK) != 0 && png_ptr->bit_depth < 8) 4430 max_pixel_depth = 8; 4431 #endif 4432 4433 #ifdef PNG_READ_EXPAND_SUPPORTED 4434 if ((png_ptr->transformations & PNG_EXPAND) != 0) 4435 { 4436 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) 4437 { 4438 if (png_ptr->num_trans != 0) 4439 max_pixel_depth = 32; 4440 4441 else 4442 max_pixel_depth = 24; 4443 } 4444 4445 else if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY) 4446 { 4447 if (max_pixel_depth < 8) 4448 max_pixel_depth = 8; 4449 4450 if (png_ptr->num_trans != 0) 4451 max_pixel_depth *= 2; 4452 } 4453 4454 else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB) 4455 { 4456 if (png_ptr->num_trans != 0) 4457 { 4458 max_pixel_depth *= 4; 4459 max_pixel_depth /= 3; 4460 } 4461 } 4462 } 4463 #endif 4464 4465 #ifdef PNG_READ_EXPAND_16_SUPPORTED 4466 if ((png_ptr->transformations & PNG_EXPAND_16) != 0) 4467 { 4468 # ifdef PNG_READ_EXPAND_SUPPORTED 4469 /* In fact it is an error if it isn't supported, but checking is 4470 * the safe way. 4471 */ 4472 if ((png_ptr->transformations & PNG_EXPAND) != 0) 4473 { 4474 if (png_ptr->bit_depth < 16) 4475 max_pixel_depth *= 2; 4476 } 4477 else 4478 # endif 4479 png_ptr->transformations &= ~PNG_EXPAND_16; 4480 } 4481 #endif 4482 4483 #ifdef PNG_READ_FILLER_SUPPORTED 4484 if ((png_ptr->transformations & (PNG_FILLER)) != 0) 4485 { 4486 if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY) 4487 { 4488 if (max_pixel_depth <= 8) 4489 max_pixel_depth = 16; 4490 4491 else 4492 max_pixel_depth = 32; 4493 } 4494 4495 else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB || 4496 png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) 4497 { 4498 if (max_pixel_depth <= 32) 4499 max_pixel_depth = 32; 4500 4501 else 4502 max_pixel_depth = 64; 4503 } 4504 } 4505 #endif 4506 4507 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED 4508 if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0) 4509 { 4510 if ( 4511 #ifdef PNG_READ_EXPAND_SUPPORTED 4512 (png_ptr->num_trans != 0 && 4513 (png_ptr->transformations & PNG_EXPAND) != 0) || 4514 #endif 4515 #ifdef PNG_READ_FILLER_SUPPORTED 4516 (png_ptr->transformations & (PNG_FILLER)) != 0 || 4517 #endif 4518 png_ptr->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) 4519 { 4520 if (max_pixel_depth <= 16) 4521 max_pixel_depth = 32; 4522 4523 else 4524 max_pixel_depth = 64; 4525 } 4526 4527 else 4528 { 4529 if (max_pixel_depth <= 8) 4530 { 4531 if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA) 4532 max_pixel_depth = 32; 4533 4534 else 4535 max_pixel_depth = 24; 4536 } 4537 4538 else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA) 4539 max_pixel_depth = 64; 4540 4541 else 4542 max_pixel_depth = 48; 4543 } 4544 } 4545 #endif 4546 4547 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) && \ 4548 defined(PNG_USER_TRANSFORM_PTR_SUPPORTED) 4549 if ((png_ptr->transformations & PNG_USER_TRANSFORM) != 0) 4550 { 4551 unsigned int user_pixel_depth = png_ptr->user_transform_depth * 4552 png_ptr->user_transform_channels; 4553 4554 if (user_pixel_depth > max_pixel_depth) 4555 max_pixel_depth = user_pixel_depth; 4556 } 4557 #endif 4558 4559 /* This value is stored in png_struct and double checked in the row read 4560 * code. 4561 */ 4562 png_ptr->maximum_pixel_depth = (png_byte)max_pixel_depth; 4563 png_ptr->transformed_pixel_depth = 0; /* calculated on demand */ 4564 4565 /* Align the width on the next larger 8 pixels. Mainly used 4566 * for interlacing 4567 */ 4568 row_bytes = ((png_ptr->width + 7) & ~((png_uint_32)7)); 4569 /* Calculate the maximum bytes needed, adding a byte and a pixel 4570 * for safety's sake 4571 */ 4572 row_bytes = PNG_ROWBYTES(max_pixel_depth, row_bytes) + 4573 1 + ((max_pixel_depth + 7) >> 3U); 4574 4575 #ifdef PNG_MAX_MALLOC_64K 4576 if (row_bytes > (png_uint_32)65536L) 4577 png_error(png_ptr, "This image requires a row greater than 64KB"); 4578 #endif 4579 4580 if (row_bytes + 48 > png_ptr->old_big_row_buf_size) 4581 { 4582 png_free(png_ptr, png_ptr->big_row_buf); 4583 png_free(png_ptr, png_ptr->big_prev_row); 4584 4585 if (png_ptr->interlaced != 0) 4586 png_ptr->big_row_buf = (png_bytep)png_calloc(png_ptr, 4587 row_bytes + 48); 4588 4589 else 4590 png_ptr->big_row_buf = (png_bytep)png_malloc(png_ptr, row_bytes + 48); 4591 4592 png_ptr->big_prev_row = (png_bytep)png_malloc(png_ptr, row_bytes + 48); 4593 4594 #ifdef PNG_ALIGNED_MEMORY_SUPPORTED 4595 /* Use 16-byte aligned memory for row_buf with at least 16 bytes 4596 * of padding before and after row_buf; treat prev_row similarly. 4597 * NOTE: the alignment is to the start of the pixels, one beyond the start 4598 * of the buffer, because of the filter byte. Prior to libpng 1.5.6 this 4599 * was incorrect; the filter byte was aligned, which had the exact 4600 * opposite effect of that intended. 4601 */ 4602 { 4603 png_bytep temp = png_ptr->big_row_buf + 32; 4604 int extra = (int)((temp - (png_bytep)0) & 0x0f); 4605 png_ptr->row_buf = temp - extra - 1/*filter byte*/; 4606 4607 temp = png_ptr->big_prev_row + 32; 4608 extra = (int)((temp - (png_bytep)0) & 0x0f); 4609 png_ptr->prev_row = temp - extra - 1/*filter byte*/; 4610 } 4611 4612 #else 4613 /* Use 31 bytes of padding before and 17 bytes after row_buf. */ 4614 png_ptr->row_buf = png_ptr->big_row_buf + 31; 4615 png_ptr->prev_row = png_ptr->big_prev_row + 31; 4616 #endif 4617 png_ptr->old_big_row_buf_size = row_bytes + 48; 4618 } 4619 4620 #ifdef PNG_MAX_MALLOC_64K 4621 if (png_ptr->rowbytes > 65535) 4622 png_error(png_ptr, "This image requires a row greater than 64KB"); 4623 4624 #endif 4625 if (png_ptr->rowbytes > (PNG_SIZE_MAX - 1)) 4626 png_error(png_ptr, "Row has too many bytes to allocate in memory"); 4627 4628 memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1); 4629 4630 png_debug1(3, "width = %u,", png_ptr->width); 4631 png_debug1(3, "height = %u,", png_ptr->height); 4632 png_debug1(3, "iwidth = %u,", png_ptr->iwidth); 4633 png_debug1(3, "num_rows = %u,", png_ptr->num_rows); 4634 png_debug1(3, "rowbytes = %lu,", (unsigned long)png_ptr->rowbytes); 4635 png_debug1(3, "irowbytes = %lu", 4636 (unsigned long)PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->iwidth) + 1); 4637 4638 /* The sequential reader needs a buffer for IDAT, but the progressive reader 4639 * does not, so free the read buffer now regardless; the sequential reader 4640 * reallocates it on demand. 4641 */ 4642 if (png_ptr->read_buffer != NULL) 4643 { 4644 png_bytep buffer = png_ptr->read_buffer; 4645 4646 png_ptr->read_buffer_size = 0; 4647 png_ptr->read_buffer = NULL; 4648 png_free(png_ptr, buffer); 4649 } 4650 4651 /* Finally claim the zstream for the inflate of the IDAT data, use the bits 4652 * value from the stream (note that this will result in a fatal error if the 4653 * IDAT stream has a bogus deflate header window_bits value, but this should 4654 * not be happening any longer!) 4655 */ 4656 if (png_inflate_claim(png_ptr, png_IDAT) != Z_OK) 4657 png_error(png_ptr, png_ptr->zstream.msg); 4658 4659 png_ptr->flags |= PNG_FLAG_ROW_INIT; 4660 } 4661 #endif /* READ */ 4662