1 2 /* pngrutil.c - utilities to read a PNG file 3 * 4 * Copyright (c) 2018 Cosmin Truta 5 * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson 6 * Copyright (c) 1996-1997 Andreas Dilger 7 * 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 accommodate 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 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 png_uint_32 profile_length = png_get_uint_32(profile_header); 1465 1466 if (png_icc_check_length(png_ptr, &png_ptr->colorspace, 1467 keyword, profile_length) != 0) 1468 { 1469 /* The length is apparently ok, so we can check the 132 1470 * byte header. 1471 */ 1472 if (png_icc_check_header(png_ptr, &png_ptr->colorspace, 1473 keyword, profile_length, profile_header, 1474 png_ptr->color_type) != 0) 1475 { 1476 /* Now read the tag table; a variable size buffer is 1477 * needed at this point, allocate one for the whole 1478 * profile. The header check has already validated 1479 * that none of this stuff will overflow. 1480 */ 1481 png_uint_32 tag_count = 1482 png_get_uint_32(profile_header + 128); 1483 png_bytep profile = png_read_buffer(png_ptr, 1484 profile_length, 2/*silent*/); 1485 1486 if (profile != NULL) 1487 { 1488 memcpy(profile, profile_header, 1489 (sizeof profile_header)); 1490 1491 size = 12 * tag_count; 1492 1493 (void)png_inflate_read(png_ptr, local_buffer, 1494 (sizeof local_buffer), &length, 1495 profile + (sizeof profile_header), &size, 0); 1496 1497 /* Still expect a buffer error because we expect 1498 * there to be some tag data! 1499 */ 1500 if (size == 0) 1501 { 1502 if (png_icc_check_tag_table(png_ptr, 1503 &png_ptr->colorspace, keyword, profile_length, 1504 profile) != 0) 1505 { 1506 /* The profile has been validated for basic 1507 * security issues, so read the whole thing in. 1508 */ 1509 size = profile_length - (sizeof profile_header) 1510 - 12 * tag_count; 1511 1512 (void)png_inflate_read(png_ptr, local_buffer, 1513 (sizeof local_buffer), &length, 1514 profile + (sizeof profile_header) + 1515 12 * tag_count, &size, 1/*finish*/); 1516 1517 if (length > 0 && !(png_ptr->flags & 1518 PNG_FLAG_BENIGN_ERRORS_WARN)) 1519 errmsg = "extra compressed data"; 1520 1521 /* But otherwise allow extra data: */ 1522 else if (size == 0) 1523 { 1524 if (length > 0) 1525 { 1526 /* This can be handled completely, so 1527 * keep going. 1528 */ 1529 png_chunk_warning(png_ptr, 1530 "extra compressed data"); 1531 } 1532 1533 png_crc_finish(png_ptr, length); 1534 finished = 1; 1535 1536 # if defined(PNG_sRGB_SUPPORTED) && PNG_sRGB_PROFILE_CHECKS >= 0 1537 /* Check for a match against sRGB */ 1538 png_icc_set_sRGB(png_ptr, 1539 &png_ptr->colorspace, profile, 1540 png_ptr->zstream.adler); 1541 # endif 1542 1543 /* Steal the profile for info_ptr. */ 1544 if (info_ptr != NULL) 1545 { 1546 png_free_data(png_ptr, info_ptr, 1547 PNG_FREE_ICCP, 0); 1548 1549 info_ptr->iccp_name = png_voidcast(char*, 1550 png_malloc_base(png_ptr, 1551 keyword_length+1)); 1552 if (info_ptr->iccp_name != NULL) 1553 { 1554 memcpy(info_ptr->iccp_name, keyword, 1555 keyword_length+1); 1556 info_ptr->iccp_proflen = 1557 profile_length; 1558 info_ptr->iccp_profile = profile; 1559 png_ptr->read_buffer = NULL; /*steal*/ 1560 info_ptr->free_me |= PNG_FREE_ICCP; 1561 info_ptr->valid |= PNG_INFO_iCCP; 1562 } 1563 1564 else 1565 { 1566 png_ptr->colorspace.flags |= 1567 PNG_COLORSPACE_INVALID; 1568 errmsg = "out of memory"; 1569 } 1570 } 1571 1572 /* else the profile remains in the read 1573 * buffer which gets reused for subsequent 1574 * chunks. 1575 */ 1576 1577 if (info_ptr != NULL) 1578 png_colorspace_sync(png_ptr, info_ptr); 1579 1580 if (errmsg == NULL) 1581 { 1582 png_ptr->zowner = 0; 1583 return; 1584 } 1585 } 1586 if (errmsg == NULL) 1587 errmsg = png_ptr->zstream.msg; 1588 } 1589 /* else png_icc_check_tag_table output an error */ 1590 } 1591 else /* profile truncated */ 1592 errmsg = png_ptr->zstream.msg; 1593 } 1594 1595 else 1596 errmsg = "out of memory"; 1597 } 1598 1599 /* else png_icc_check_header output an error */ 1600 } 1601 1602 /* else png_icc_check_length output an error */ 1603 } 1604 1605 else /* profile truncated */ 1606 errmsg = png_ptr->zstream.msg; 1607 1608 /* Release the stream */ 1609 png_ptr->zowner = 0; 1610 } 1611 1612 else /* png_inflate_claim failed */ 1613 errmsg = png_ptr->zstream.msg; 1614 } 1615 1616 else 1617 errmsg = "bad compression method"; /* or missing */ 1618 } 1619 1620 else 1621 errmsg = "bad keyword"; 1622 } 1623 1624 else 1625 errmsg = "too many profiles"; 1626 1627 /* Failure: the reason is in 'errmsg' */ 1628 if (finished == 0) 1629 png_crc_finish(png_ptr, length); 1630 1631 png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID; 1632 png_colorspace_sync(png_ptr, info_ptr); 1633 if (errmsg != NULL) /* else already output */ 1634 png_chunk_benign_error(png_ptr, errmsg); 1635 } 1636 #endif /* READ_iCCP */ 1637 1638 #ifdef PNG_READ_sPLT_SUPPORTED 1639 void /* PRIVATE */ 1640 png_handle_sPLT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 1641 /* Note: this does not properly handle chunks that are > 64K under DOS */ 1642 { 1643 png_bytep entry_start, buffer; 1644 png_sPLT_t new_palette; 1645 png_sPLT_entryp pp; 1646 png_uint_32 data_length; 1647 int entry_size, i; 1648 png_uint_32 skip = 0; 1649 png_uint_32 dl; 1650 size_t max_dl; 1651 1652 png_debug(1, "in png_handle_sPLT"); 1653 1654 #ifdef PNG_USER_LIMITS_SUPPORTED 1655 if (png_ptr->user_chunk_cache_max != 0) 1656 { 1657 if (png_ptr->user_chunk_cache_max == 1) 1658 { 1659 png_crc_finish(png_ptr, length); 1660 return; 1661 } 1662 1663 if (--png_ptr->user_chunk_cache_max == 1) 1664 { 1665 png_warning(png_ptr, "No space in chunk cache for sPLT"); 1666 png_crc_finish(png_ptr, length); 1667 return; 1668 } 1669 } 1670 #endif 1671 1672 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 1673 png_chunk_error(png_ptr, "missing IHDR"); 1674 1675 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) 1676 { 1677 png_crc_finish(png_ptr, length); 1678 png_chunk_benign_error(png_ptr, "out of place"); 1679 return; 1680 } 1681 1682 #ifdef PNG_MAX_MALLOC_64K 1683 if (length > 65535U) 1684 { 1685 png_crc_finish(png_ptr, length); 1686 png_chunk_benign_error(png_ptr, "too large to fit in memory"); 1687 return; 1688 } 1689 #endif 1690 1691 buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/); 1692 if (buffer == NULL) 1693 { 1694 png_crc_finish(png_ptr, length); 1695 png_chunk_benign_error(png_ptr, "out of memory"); 1696 return; 1697 } 1698 1699 1700 /* WARNING: this may break if size_t is less than 32 bits; it is assumed 1701 * that the PNG_MAX_MALLOC_64K test is enabled in this case, but this is a 1702 * potential breakage point if the types in pngconf.h aren't exactly right. 1703 */ 1704 png_crc_read(png_ptr, buffer, length); 1705 1706 if (png_crc_finish(png_ptr, skip) != 0) 1707 return; 1708 1709 buffer[length] = 0; 1710 1711 for (entry_start = buffer; *entry_start; entry_start++) 1712 /* Empty loop to find end of name */ ; 1713 1714 ++entry_start; 1715 1716 /* A sample depth should follow the separator, and we should be on it */ 1717 if (length < 2U || entry_start > buffer + (length - 2U)) 1718 { 1719 png_warning(png_ptr, "malformed sPLT chunk"); 1720 return; 1721 } 1722 1723 new_palette.depth = *entry_start++; 1724 entry_size = (new_palette.depth == 8 ? 6 : 10); 1725 /* This must fit in a png_uint_32 because it is derived from the original 1726 * chunk data length. 1727 */ 1728 data_length = length - (png_uint_32)(entry_start - buffer); 1729 1730 /* Integrity-check the data length */ 1731 if ((data_length % (unsigned int)entry_size) != 0) 1732 { 1733 png_warning(png_ptr, "sPLT chunk has bad length"); 1734 return; 1735 } 1736 1737 dl = (png_uint_32)(data_length / (unsigned int)entry_size); 1738 max_dl = PNG_SIZE_MAX / (sizeof (png_sPLT_entry)); 1739 1740 if (dl > max_dl) 1741 { 1742 png_warning(png_ptr, "sPLT chunk too long"); 1743 return; 1744 } 1745 1746 new_palette.nentries = (png_int_32)(data_length / (unsigned int)entry_size); 1747 1748 new_palette.entries = (png_sPLT_entryp)png_malloc_warn(png_ptr, 1749 (png_alloc_size_t) new_palette.nentries * (sizeof (png_sPLT_entry))); 1750 1751 if (new_palette.entries == NULL) 1752 { 1753 png_warning(png_ptr, "sPLT chunk requires too much memory"); 1754 return; 1755 } 1756 1757 #ifdef PNG_POINTER_INDEXING_SUPPORTED 1758 for (i = 0; i < new_palette.nentries; i++) 1759 { 1760 pp = new_palette.entries + i; 1761 1762 if (new_palette.depth == 8) 1763 { 1764 pp->red = *entry_start++; 1765 pp->green = *entry_start++; 1766 pp->blue = *entry_start++; 1767 pp->alpha = *entry_start++; 1768 } 1769 1770 else 1771 { 1772 pp->red = png_get_uint_16(entry_start); entry_start += 2; 1773 pp->green = png_get_uint_16(entry_start); entry_start += 2; 1774 pp->blue = png_get_uint_16(entry_start); entry_start += 2; 1775 pp->alpha = png_get_uint_16(entry_start); entry_start += 2; 1776 } 1777 1778 pp->frequency = png_get_uint_16(entry_start); entry_start += 2; 1779 } 1780 #else 1781 pp = new_palette.entries; 1782 1783 for (i = 0; i < new_palette.nentries; i++) 1784 { 1785 1786 if (new_palette.depth == 8) 1787 { 1788 pp[i].red = *entry_start++; 1789 pp[i].green = *entry_start++; 1790 pp[i].blue = *entry_start++; 1791 pp[i].alpha = *entry_start++; 1792 } 1793 1794 else 1795 { 1796 pp[i].red = png_get_uint_16(entry_start); entry_start += 2; 1797 pp[i].green = png_get_uint_16(entry_start); entry_start += 2; 1798 pp[i].blue = png_get_uint_16(entry_start); entry_start += 2; 1799 pp[i].alpha = png_get_uint_16(entry_start); entry_start += 2; 1800 } 1801 1802 pp[i].frequency = png_get_uint_16(entry_start); entry_start += 2; 1803 } 1804 #endif 1805 1806 /* Discard all chunk data except the name and stash that */ 1807 new_palette.name = (png_charp)buffer; 1808 1809 png_set_sPLT(png_ptr, info_ptr, &new_palette, 1); 1810 1811 png_free(png_ptr, new_palette.entries); 1812 } 1813 #endif /* READ_sPLT */ 1814 1815 #ifdef PNG_READ_tRNS_SUPPORTED 1816 void /* PRIVATE */ 1817 png_handle_tRNS(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 1818 { 1819 png_byte readbuf[PNG_MAX_PALETTE_LENGTH]; 1820 1821 png_debug(1, "in png_handle_tRNS"); 1822 1823 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 1824 png_chunk_error(png_ptr, "missing IHDR"); 1825 1826 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) 1827 { 1828 png_crc_finish(png_ptr, length); 1829 png_chunk_benign_error(png_ptr, "out of place"); 1830 return; 1831 } 1832 1833 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS) != 0) 1834 { 1835 png_crc_finish(png_ptr, length); 1836 png_chunk_benign_error(png_ptr, "duplicate"); 1837 return; 1838 } 1839 1840 if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY) 1841 { 1842 png_byte buf[2]; 1843 1844 if (length != 2) 1845 { 1846 png_crc_finish(png_ptr, length); 1847 png_chunk_benign_error(png_ptr, "invalid"); 1848 return; 1849 } 1850 1851 png_crc_read(png_ptr, buf, 2); 1852 png_ptr->num_trans = 1; 1853 png_ptr->trans_color.gray = png_get_uint_16(buf); 1854 } 1855 1856 else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB) 1857 { 1858 png_byte buf[6]; 1859 1860 if (length != 6) 1861 { 1862 png_crc_finish(png_ptr, length); 1863 png_chunk_benign_error(png_ptr, "invalid"); 1864 return; 1865 } 1866 1867 png_crc_read(png_ptr, buf, length); 1868 png_ptr->num_trans = 1; 1869 png_ptr->trans_color.red = png_get_uint_16(buf); 1870 png_ptr->trans_color.green = png_get_uint_16(buf + 2); 1871 png_ptr->trans_color.blue = png_get_uint_16(buf + 4); 1872 } 1873 1874 else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) 1875 { 1876 if ((png_ptr->mode & PNG_HAVE_PLTE) == 0) 1877 { 1878 /* TODO: is this actually an error in the ISO spec? */ 1879 png_crc_finish(png_ptr, length); 1880 png_chunk_benign_error(png_ptr, "out of place"); 1881 return; 1882 } 1883 1884 if (length > (unsigned int) png_ptr->num_palette || 1885 length > (unsigned int) PNG_MAX_PALETTE_LENGTH || 1886 length == 0) 1887 { 1888 png_crc_finish(png_ptr, length); 1889 png_chunk_benign_error(png_ptr, "invalid"); 1890 return; 1891 } 1892 1893 png_crc_read(png_ptr, readbuf, length); 1894 png_ptr->num_trans = (png_uint_16)length; 1895 } 1896 1897 else 1898 { 1899 png_crc_finish(png_ptr, length); 1900 png_chunk_benign_error(png_ptr, "invalid with alpha channel"); 1901 return; 1902 } 1903 1904 if (png_crc_finish(png_ptr, 0) != 0) 1905 { 1906 png_ptr->num_trans = 0; 1907 return; 1908 } 1909 1910 /* TODO: this is a horrible side effect in the palette case because the 1911 * png_struct ends up with a pointer to the tRNS buffer owned by the 1912 * png_info. Fix this. 1913 */ 1914 png_set_tRNS(png_ptr, info_ptr, readbuf, png_ptr->num_trans, 1915 &(png_ptr->trans_color)); 1916 } 1917 #endif 1918 1919 #ifdef PNG_READ_bKGD_SUPPORTED 1920 void /* PRIVATE */ 1921 png_handle_bKGD(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 1922 { 1923 unsigned int truelen; 1924 png_byte buf[6]; 1925 png_color_16 background; 1926 1927 png_debug(1, "in png_handle_bKGD"); 1928 1929 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 1930 png_chunk_error(png_ptr, "missing IHDR"); 1931 1932 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0 || 1933 (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE && 1934 (png_ptr->mode & PNG_HAVE_PLTE) == 0)) 1935 { 1936 png_crc_finish(png_ptr, length); 1937 png_chunk_benign_error(png_ptr, "out of place"); 1938 return; 1939 } 1940 1941 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD) != 0) 1942 { 1943 png_crc_finish(png_ptr, length); 1944 png_chunk_benign_error(png_ptr, "duplicate"); 1945 return; 1946 } 1947 1948 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) 1949 truelen = 1; 1950 1951 else if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0) 1952 truelen = 6; 1953 1954 else 1955 truelen = 2; 1956 1957 if (length != truelen) 1958 { 1959 png_crc_finish(png_ptr, length); 1960 png_chunk_benign_error(png_ptr, "invalid"); 1961 return; 1962 } 1963 1964 png_crc_read(png_ptr, buf, truelen); 1965 1966 if (png_crc_finish(png_ptr, 0) != 0) 1967 return; 1968 1969 /* We convert the index value into RGB components so that we can allow 1970 * arbitrary RGB values for background when we have transparency, and 1971 * so it is easy to determine the RGB values of the background color 1972 * from the info_ptr struct. 1973 */ 1974 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) 1975 { 1976 background.index = buf[0]; 1977 1978 if (info_ptr != NULL && info_ptr->num_palette != 0) 1979 { 1980 if (buf[0] >= info_ptr->num_palette) 1981 { 1982 png_chunk_benign_error(png_ptr, "invalid index"); 1983 return; 1984 } 1985 1986 background.red = (png_uint_16)png_ptr->palette[buf[0]].red; 1987 background.green = (png_uint_16)png_ptr->palette[buf[0]].green; 1988 background.blue = (png_uint_16)png_ptr->palette[buf[0]].blue; 1989 } 1990 1991 else 1992 background.red = background.green = background.blue = 0; 1993 1994 background.gray = 0; 1995 } 1996 1997 else if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0) /* GRAY */ 1998 { 1999 if (png_ptr->bit_depth <= 8) 2000 { 2001 if (buf[0] != 0 || buf[1] >= (unsigned int)(1 << png_ptr->bit_depth)) 2002 { 2003 png_chunk_benign_error(png_ptr, "invalid gray level"); 2004 return; 2005 } 2006 } 2007 2008 background.index = 0; 2009 background.red = 2010 background.green = 2011 background.blue = 2012 background.gray = png_get_uint_16(buf); 2013 } 2014 2015 else 2016 { 2017 if (png_ptr->bit_depth <= 8) 2018 { 2019 if (buf[0] != 0 || buf[2] != 0 || buf[4] != 0) 2020 { 2021 png_chunk_benign_error(png_ptr, "invalid color"); 2022 return; 2023 } 2024 } 2025 2026 background.index = 0; 2027 background.red = png_get_uint_16(buf); 2028 background.green = png_get_uint_16(buf + 2); 2029 background.blue = png_get_uint_16(buf + 4); 2030 background.gray = 0; 2031 } 2032 2033 png_set_bKGD(png_ptr, info_ptr, &background); 2034 } 2035 #endif 2036 2037 #ifdef PNG_READ_eXIf_SUPPORTED 2038 void /* PRIVATE */ 2039 png_handle_eXIf(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 2040 { 2041 unsigned int i; 2042 2043 png_debug(1, "in png_handle_eXIf"); 2044 2045 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 2046 png_chunk_error(png_ptr, "missing IHDR"); 2047 2048 if (length < 2) 2049 { 2050 png_crc_finish(png_ptr, length); 2051 png_chunk_benign_error(png_ptr, "too short"); 2052 return; 2053 } 2054 2055 else if (info_ptr == NULL || (info_ptr->valid & PNG_INFO_eXIf) != 0) 2056 { 2057 png_crc_finish(png_ptr, length); 2058 png_chunk_benign_error(png_ptr, "duplicate"); 2059 return; 2060 } 2061 2062 info_ptr->free_me |= PNG_FREE_EXIF; 2063 2064 info_ptr->eXIf_buf = png_voidcast(png_bytep, 2065 png_malloc_warn(png_ptr, length)); 2066 2067 if (info_ptr->eXIf_buf == NULL) 2068 { 2069 png_crc_finish(png_ptr, length); 2070 png_chunk_benign_error(png_ptr, "out of memory"); 2071 return; 2072 } 2073 2074 for (i = 0; i < length; i++) 2075 { 2076 png_byte buf[1]; 2077 png_crc_read(png_ptr, buf, 1); 2078 info_ptr->eXIf_buf[i] = buf[0]; 2079 if (i == 1 && buf[0] != 'M' && buf[0] != 'I' 2080 && info_ptr->eXIf_buf[0] != buf[0]) 2081 { 2082 png_crc_finish(png_ptr, length); 2083 png_chunk_benign_error(png_ptr, "incorrect byte-order specifier"); 2084 png_free(png_ptr, info_ptr->eXIf_buf); 2085 info_ptr->eXIf_buf = NULL; 2086 return; 2087 } 2088 } 2089 2090 if (png_crc_finish(png_ptr, 0) != 0) 2091 return; 2092 2093 png_set_eXIf_1(png_ptr, info_ptr, length, info_ptr->eXIf_buf); 2094 2095 png_free(png_ptr, info_ptr->eXIf_buf); 2096 info_ptr->eXIf_buf = NULL; 2097 } 2098 #endif 2099 2100 #ifdef PNG_READ_hIST_SUPPORTED 2101 void /* PRIVATE */ 2102 png_handle_hIST(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 2103 { 2104 unsigned int num, i; 2105 png_uint_16 readbuf[PNG_MAX_PALETTE_LENGTH]; 2106 2107 png_debug(1, "in png_handle_hIST"); 2108 2109 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 2110 png_chunk_error(png_ptr, "missing IHDR"); 2111 2112 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0 || 2113 (png_ptr->mode & PNG_HAVE_PLTE) == 0) 2114 { 2115 png_crc_finish(png_ptr, length); 2116 png_chunk_benign_error(png_ptr, "out of place"); 2117 return; 2118 } 2119 2120 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST) != 0) 2121 { 2122 png_crc_finish(png_ptr, length); 2123 png_chunk_benign_error(png_ptr, "duplicate"); 2124 return; 2125 } 2126 2127 num = length / 2 ; 2128 2129 if (num != (unsigned int) png_ptr->num_palette || 2130 num > (unsigned int) PNG_MAX_PALETTE_LENGTH) 2131 { 2132 png_crc_finish(png_ptr, length); 2133 png_chunk_benign_error(png_ptr, "invalid"); 2134 return; 2135 } 2136 2137 for (i = 0; i < num; i++) 2138 { 2139 png_byte buf[2]; 2140 2141 png_crc_read(png_ptr, buf, 2); 2142 readbuf[i] = png_get_uint_16(buf); 2143 } 2144 2145 if (png_crc_finish(png_ptr, 0) != 0) 2146 return; 2147 2148 png_set_hIST(png_ptr, info_ptr, readbuf); 2149 } 2150 #endif 2151 2152 #ifdef PNG_READ_pHYs_SUPPORTED 2153 void /* PRIVATE */ 2154 png_handle_pHYs(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 2155 { 2156 png_byte buf[9]; 2157 png_uint_32 res_x, res_y; 2158 int unit_type; 2159 2160 png_debug(1, "in png_handle_pHYs"); 2161 2162 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 2163 png_chunk_error(png_ptr, "missing IHDR"); 2164 2165 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) 2166 { 2167 png_crc_finish(png_ptr, length); 2168 png_chunk_benign_error(png_ptr, "out of place"); 2169 return; 2170 } 2171 2172 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs) != 0) 2173 { 2174 png_crc_finish(png_ptr, length); 2175 png_chunk_benign_error(png_ptr, "duplicate"); 2176 return; 2177 } 2178 2179 if (length != 9) 2180 { 2181 png_crc_finish(png_ptr, length); 2182 png_chunk_benign_error(png_ptr, "invalid"); 2183 return; 2184 } 2185 2186 png_crc_read(png_ptr, buf, 9); 2187 2188 if (png_crc_finish(png_ptr, 0) != 0) 2189 return; 2190 2191 res_x = png_get_uint_32(buf); 2192 res_y = png_get_uint_32(buf + 4); 2193 unit_type = buf[8]; 2194 png_set_pHYs(png_ptr, info_ptr, res_x, res_y, unit_type); 2195 } 2196 #endif 2197 2198 #ifdef PNG_READ_oFFs_SUPPORTED 2199 void /* PRIVATE */ 2200 png_handle_oFFs(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 2201 { 2202 png_byte buf[9]; 2203 png_int_32 offset_x, offset_y; 2204 int unit_type; 2205 2206 png_debug(1, "in png_handle_oFFs"); 2207 2208 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 2209 png_chunk_error(png_ptr, "missing IHDR"); 2210 2211 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) 2212 { 2213 png_crc_finish(png_ptr, length); 2214 png_chunk_benign_error(png_ptr, "out of place"); 2215 return; 2216 } 2217 2218 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs) != 0) 2219 { 2220 png_crc_finish(png_ptr, length); 2221 png_chunk_benign_error(png_ptr, "duplicate"); 2222 return; 2223 } 2224 2225 if (length != 9) 2226 { 2227 png_crc_finish(png_ptr, length); 2228 png_chunk_benign_error(png_ptr, "invalid"); 2229 return; 2230 } 2231 2232 png_crc_read(png_ptr, buf, 9); 2233 2234 if (png_crc_finish(png_ptr, 0) != 0) 2235 return; 2236 2237 offset_x = png_get_int_32(buf); 2238 offset_y = png_get_int_32(buf + 4); 2239 unit_type = buf[8]; 2240 png_set_oFFs(png_ptr, info_ptr, offset_x, offset_y, unit_type); 2241 } 2242 #endif 2243 2244 #ifdef PNG_READ_pCAL_SUPPORTED 2245 /* Read the pCAL chunk (described in the PNG Extensions document) */ 2246 void /* PRIVATE */ 2247 png_handle_pCAL(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 2248 { 2249 png_int_32 X0, X1; 2250 png_byte type, nparams; 2251 png_bytep buffer, buf, units, endptr; 2252 png_charpp params; 2253 int i; 2254 2255 png_debug(1, "in png_handle_pCAL"); 2256 2257 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 2258 png_chunk_error(png_ptr, "missing IHDR"); 2259 2260 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) 2261 { 2262 png_crc_finish(png_ptr, length); 2263 png_chunk_benign_error(png_ptr, "out of place"); 2264 return; 2265 } 2266 2267 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pCAL) != 0) 2268 { 2269 png_crc_finish(png_ptr, length); 2270 png_chunk_benign_error(png_ptr, "duplicate"); 2271 return; 2272 } 2273 2274 png_debug1(2, "Allocating and reading pCAL chunk data (%u bytes)", 2275 length + 1); 2276 2277 buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/); 2278 2279 if (buffer == NULL) 2280 { 2281 png_crc_finish(png_ptr, length); 2282 png_chunk_benign_error(png_ptr, "out of memory"); 2283 return; 2284 } 2285 2286 png_crc_read(png_ptr, buffer, length); 2287 2288 if (png_crc_finish(png_ptr, 0) != 0) 2289 return; 2290 2291 buffer[length] = 0; /* Null terminate the last string */ 2292 2293 png_debug(3, "Finding end of pCAL purpose string"); 2294 for (buf = buffer; *buf; buf++) 2295 /* Empty loop */ ; 2296 2297 endptr = buffer + length; 2298 2299 /* We need to have at least 12 bytes after the purpose string 2300 * in order to get the parameter information. 2301 */ 2302 if (endptr - buf <= 12) 2303 { 2304 png_chunk_benign_error(png_ptr, "invalid"); 2305 return; 2306 } 2307 2308 png_debug(3, "Reading pCAL X0, X1, type, nparams, and units"); 2309 X0 = png_get_int_32((png_bytep)buf+1); 2310 X1 = png_get_int_32((png_bytep)buf+5); 2311 type = buf[9]; 2312 nparams = buf[10]; 2313 units = buf + 11; 2314 2315 png_debug(3, "Checking pCAL equation type and number of parameters"); 2316 /* Check that we have the right number of parameters for known 2317 * equation types. 2318 */ 2319 if ((type == PNG_EQUATION_LINEAR && nparams != 2) || 2320 (type == PNG_EQUATION_BASE_E && nparams != 3) || 2321 (type == PNG_EQUATION_ARBITRARY && nparams != 3) || 2322 (type == PNG_EQUATION_HYPERBOLIC && nparams != 4)) 2323 { 2324 png_chunk_benign_error(png_ptr, "invalid parameter count"); 2325 return; 2326 } 2327 2328 else if (type >= PNG_EQUATION_LAST) 2329 { 2330 png_chunk_benign_error(png_ptr, "unrecognized equation type"); 2331 } 2332 2333 for (buf = units; *buf; buf++) 2334 /* Empty loop to move past the units string. */ ; 2335 2336 png_debug(3, "Allocating pCAL parameters array"); 2337 2338 params = png_voidcast(png_charpp, png_malloc_warn(png_ptr, 2339 nparams * (sizeof (png_charp)))); 2340 2341 if (params == NULL) 2342 { 2343 png_chunk_benign_error(png_ptr, "out of memory"); 2344 return; 2345 } 2346 2347 /* Get pointers to the start of each parameter string. */ 2348 for (i = 0; i < nparams; i++) 2349 { 2350 buf++; /* Skip the null string terminator from previous parameter. */ 2351 2352 png_debug1(3, "Reading pCAL parameter %d", i); 2353 2354 for (params[i] = (png_charp)buf; buf <= endptr && *buf != 0; buf++) 2355 /* Empty loop to move past each parameter string */ ; 2356 2357 /* Make sure we haven't run out of data yet */ 2358 if (buf > endptr) 2359 { 2360 png_free(png_ptr, params); 2361 png_chunk_benign_error(png_ptr, "invalid data"); 2362 return; 2363 } 2364 } 2365 2366 png_set_pCAL(png_ptr, info_ptr, (png_charp)buffer, X0, X1, type, nparams, 2367 (png_charp)units, params); 2368 2369 png_free(png_ptr, params); 2370 } 2371 #endif 2372 2373 #ifdef PNG_READ_sCAL_SUPPORTED 2374 /* Read the sCAL chunk */ 2375 void /* PRIVATE */ 2376 png_handle_sCAL(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 2377 { 2378 png_bytep buffer; 2379 size_t i; 2380 int state; 2381 2382 png_debug(1, "in png_handle_sCAL"); 2383 2384 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 2385 png_chunk_error(png_ptr, "missing IHDR"); 2386 2387 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) 2388 { 2389 png_crc_finish(png_ptr, length); 2390 png_chunk_benign_error(png_ptr, "out of place"); 2391 return; 2392 } 2393 2394 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sCAL) != 0) 2395 { 2396 png_crc_finish(png_ptr, length); 2397 png_chunk_benign_error(png_ptr, "duplicate"); 2398 return; 2399 } 2400 2401 /* Need unit type, width, \0, height: minimum 4 bytes */ 2402 else if (length < 4) 2403 { 2404 png_crc_finish(png_ptr, length); 2405 png_chunk_benign_error(png_ptr, "invalid"); 2406 return; 2407 } 2408 2409 png_debug1(2, "Allocating and reading sCAL chunk data (%u bytes)", 2410 length + 1); 2411 2412 buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/); 2413 2414 if (buffer == NULL) 2415 { 2416 png_chunk_benign_error(png_ptr, "out of memory"); 2417 png_crc_finish(png_ptr, length); 2418 return; 2419 } 2420 2421 png_crc_read(png_ptr, buffer, length); 2422 buffer[length] = 0; /* Null terminate the last string */ 2423 2424 if (png_crc_finish(png_ptr, 0) != 0) 2425 return; 2426 2427 /* Validate the unit. */ 2428 if (buffer[0] != 1 && buffer[0] != 2) 2429 { 2430 png_chunk_benign_error(png_ptr, "invalid unit"); 2431 return; 2432 } 2433 2434 /* Validate the ASCII numbers, need two ASCII numbers separated by 2435 * a '\0' and they need to fit exactly in the chunk data. 2436 */ 2437 i = 1; 2438 state = 0; 2439 2440 if (png_check_fp_number((png_const_charp)buffer, length, &state, &i) == 0 || 2441 i >= length || buffer[i++] != 0) 2442 png_chunk_benign_error(png_ptr, "bad width format"); 2443 2444 else if (PNG_FP_IS_POSITIVE(state) == 0) 2445 png_chunk_benign_error(png_ptr, "non-positive width"); 2446 2447 else 2448 { 2449 size_t heighti = i; 2450 2451 state = 0; 2452 if (png_check_fp_number((png_const_charp)buffer, length, 2453 &state, &i) == 0 || i != length) 2454 png_chunk_benign_error(png_ptr, "bad height format"); 2455 2456 else if (PNG_FP_IS_POSITIVE(state) == 0) 2457 png_chunk_benign_error(png_ptr, "non-positive height"); 2458 2459 else 2460 /* This is the (only) success case. */ 2461 png_set_sCAL_s(png_ptr, info_ptr, buffer[0], 2462 (png_charp)buffer+1, (png_charp)buffer+heighti); 2463 } 2464 } 2465 #endif 2466 2467 #ifdef PNG_READ_tIME_SUPPORTED 2468 void /* PRIVATE */ 2469 png_handle_tIME(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 2470 { 2471 png_byte buf[7]; 2472 png_time mod_time; 2473 2474 png_debug(1, "in png_handle_tIME"); 2475 2476 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 2477 png_chunk_error(png_ptr, "missing IHDR"); 2478 2479 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tIME) != 0) 2480 { 2481 png_crc_finish(png_ptr, length); 2482 png_chunk_benign_error(png_ptr, "duplicate"); 2483 return; 2484 } 2485 2486 if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) 2487 png_ptr->mode |= PNG_AFTER_IDAT; 2488 2489 if (length != 7) 2490 { 2491 png_crc_finish(png_ptr, length); 2492 png_chunk_benign_error(png_ptr, "invalid"); 2493 return; 2494 } 2495 2496 png_crc_read(png_ptr, buf, 7); 2497 2498 if (png_crc_finish(png_ptr, 0) != 0) 2499 return; 2500 2501 mod_time.second = buf[6]; 2502 mod_time.minute = buf[5]; 2503 mod_time.hour = buf[4]; 2504 mod_time.day = buf[3]; 2505 mod_time.month = buf[2]; 2506 mod_time.year = png_get_uint_16(buf); 2507 2508 png_set_tIME(png_ptr, info_ptr, &mod_time); 2509 } 2510 #endif 2511 2512 #ifdef PNG_READ_tEXt_SUPPORTED 2513 /* Note: this does not properly handle chunks that are > 64K under DOS */ 2514 void /* PRIVATE */ 2515 png_handle_tEXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 2516 { 2517 png_text text_info; 2518 png_bytep buffer; 2519 png_charp key; 2520 png_charp text; 2521 png_uint_32 skip = 0; 2522 2523 png_debug(1, "in png_handle_tEXt"); 2524 2525 #ifdef PNG_USER_LIMITS_SUPPORTED 2526 if (png_ptr->user_chunk_cache_max != 0) 2527 { 2528 if (png_ptr->user_chunk_cache_max == 1) 2529 { 2530 png_crc_finish(png_ptr, length); 2531 return; 2532 } 2533 2534 if (--png_ptr->user_chunk_cache_max == 1) 2535 { 2536 png_crc_finish(png_ptr, length); 2537 png_chunk_benign_error(png_ptr, "no space in chunk cache"); 2538 return; 2539 } 2540 } 2541 #endif 2542 2543 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 2544 png_chunk_error(png_ptr, "missing IHDR"); 2545 2546 if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) 2547 png_ptr->mode |= PNG_AFTER_IDAT; 2548 2549 #ifdef PNG_MAX_MALLOC_64K 2550 if (length > 65535U) 2551 { 2552 png_crc_finish(png_ptr, length); 2553 png_chunk_benign_error(png_ptr, "too large to fit in memory"); 2554 return; 2555 } 2556 #endif 2557 2558 buffer = png_read_buffer(png_ptr, length+1, 1/*warn*/); 2559 2560 if (buffer == NULL) 2561 { 2562 png_chunk_benign_error(png_ptr, "out of memory"); 2563 return; 2564 } 2565 2566 png_crc_read(png_ptr, buffer, length); 2567 2568 if (png_crc_finish(png_ptr, skip) != 0) 2569 return; 2570 2571 key = (png_charp)buffer; 2572 key[length] = 0; 2573 2574 for (text = key; *text; text++) 2575 /* Empty loop to find end of key */ ; 2576 2577 if (text != key + length) 2578 text++; 2579 2580 text_info.compression = PNG_TEXT_COMPRESSION_NONE; 2581 text_info.key = key; 2582 text_info.lang = NULL; 2583 text_info.lang_key = NULL; 2584 text_info.itxt_length = 0; 2585 text_info.text = text; 2586 text_info.text_length = strlen(text); 2587 2588 if (png_set_text_2(png_ptr, info_ptr, &text_info, 1) != 0) 2589 png_warning(png_ptr, "Insufficient memory to process text chunk"); 2590 } 2591 #endif 2592 2593 #ifdef PNG_READ_zTXt_SUPPORTED 2594 /* Note: this does not correctly handle chunks that are > 64K under DOS */ 2595 void /* PRIVATE */ 2596 png_handle_zTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 2597 { 2598 png_const_charp errmsg = NULL; 2599 png_bytep buffer; 2600 png_uint_32 keyword_length; 2601 2602 png_debug(1, "in png_handle_zTXt"); 2603 2604 #ifdef PNG_USER_LIMITS_SUPPORTED 2605 if (png_ptr->user_chunk_cache_max != 0) 2606 { 2607 if (png_ptr->user_chunk_cache_max == 1) 2608 { 2609 png_crc_finish(png_ptr, length); 2610 return; 2611 } 2612 2613 if (--png_ptr->user_chunk_cache_max == 1) 2614 { 2615 png_crc_finish(png_ptr, length); 2616 png_chunk_benign_error(png_ptr, "no space in chunk cache"); 2617 return; 2618 } 2619 } 2620 #endif 2621 2622 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 2623 png_chunk_error(png_ptr, "missing IHDR"); 2624 2625 if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) 2626 png_ptr->mode |= PNG_AFTER_IDAT; 2627 2628 /* Note, "length" is sufficient here; we won't be adding 2629 * a null terminator later. 2630 */ 2631 buffer = png_read_buffer(png_ptr, length, 2/*silent*/); 2632 2633 if (buffer == NULL) 2634 { 2635 png_crc_finish(png_ptr, length); 2636 png_chunk_benign_error(png_ptr, "out of memory"); 2637 return; 2638 } 2639 2640 png_crc_read(png_ptr, buffer, length); 2641 2642 if (png_crc_finish(png_ptr, 0) != 0) 2643 return; 2644 2645 /* TODO: also check that the keyword contents match the spec! */ 2646 for (keyword_length = 0; 2647 keyword_length < length && buffer[keyword_length] != 0; 2648 ++keyword_length) 2649 /* Empty loop to find end of name */ ; 2650 2651 if (keyword_length > 79 || keyword_length < 1) 2652 errmsg = "bad keyword"; 2653 2654 /* zTXt must have some LZ data after the keyword, although it may expand to 2655 * zero bytes; we need a '\0' at the end of the keyword, the compression type 2656 * then the LZ data: 2657 */ 2658 else if (keyword_length + 3 > length) 2659 errmsg = "truncated"; 2660 2661 else if (buffer[keyword_length+1] != PNG_COMPRESSION_TYPE_BASE) 2662 errmsg = "unknown compression type"; 2663 2664 else 2665 { 2666 png_alloc_size_t uncompressed_length = PNG_SIZE_MAX; 2667 2668 /* TODO: at present png_decompress_chunk imposes a single application 2669 * level memory limit, this should be split to different values for iCCP 2670 * and text chunks. 2671 */ 2672 if (png_decompress_chunk(png_ptr, length, keyword_length+2, 2673 &uncompressed_length, 1/*terminate*/) == Z_STREAM_END) 2674 { 2675 png_text text; 2676 2677 if (png_ptr->read_buffer == NULL) 2678 errmsg="Read failure in png_handle_zTXt"; 2679 else 2680 { 2681 /* It worked; png_ptr->read_buffer now looks like a tEXt chunk 2682 * except for the extra compression type byte and the fact that 2683 * it isn't necessarily '\0' terminated. 2684 */ 2685 buffer = png_ptr->read_buffer; 2686 buffer[uncompressed_length+(keyword_length+2)] = 0; 2687 2688 text.compression = PNG_TEXT_COMPRESSION_zTXt; 2689 text.key = (png_charp)buffer; 2690 text.text = (png_charp)(buffer + keyword_length+2); 2691 text.text_length = uncompressed_length; 2692 text.itxt_length = 0; 2693 text.lang = NULL; 2694 text.lang_key = NULL; 2695 2696 if (png_set_text_2(png_ptr, info_ptr, &text, 1) != 0) 2697 errmsg = "insufficient memory"; 2698 } 2699 } 2700 2701 else 2702 errmsg = png_ptr->zstream.msg; 2703 } 2704 2705 if (errmsg != NULL) 2706 png_chunk_benign_error(png_ptr, errmsg); 2707 } 2708 #endif 2709 2710 #ifdef PNG_READ_iTXt_SUPPORTED 2711 /* Note: this does not correctly handle chunks that are > 64K under DOS */ 2712 void /* PRIVATE */ 2713 png_handle_iTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 2714 { 2715 png_const_charp errmsg = NULL; 2716 png_bytep buffer; 2717 png_uint_32 prefix_length; 2718 2719 png_debug(1, "in png_handle_iTXt"); 2720 2721 #ifdef PNG_USER_LIMITS_SUPPORTED 2722 if (png_ptr->user_chunk_cache_max != 0) 2723 { 2724 if (png_ptr->user_chunk_cache_max == 1) 2725 { 2726 png_crc_finish(png_ptr, length); 2727 return; 2728 } 2729 2730 if (--png_ptr->user_chunk_cache_max == 1) 2731 { 2732 png_crc_finish(png_ptr, length); 2733 png_chunk_benign_error(png_ptr, "no space in chunk cache"); 2734 return; 2735 } 2736 } 2737 #endif 2738 2739 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 2740 png_chunk_error(png_ptr, "missing IHDR"); 2741 2742 if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) 2743 png_ptr->mode |= PNG_AFTER_IDAT; 2744 2745 buffer = png_read_buffer(png_ptr, length+1, 1/*warn*/); 2746 2747 if (buffer == NULL) 2748 { 2749 png_crc_finish(png_ptr, length); 2750 png_chunk_benign_error(png_ptr, "out of memory"); 2751 return; 2752 } 2753 2754 png_crc_read(png_ptr, buffer, length); 2755 2756 if (png_crc_finish(png_ptr, 0) != 0) 2757 return; 2758 2759 /* First the keyword. */ 2760 for (prefix_length=0; 2761 prefix_length < length && buffer[prefix_length] != 0; 2762 ++prefix_length) 2763 /* Empty loop */ ; 2764 2765 /* Perform a basic check on the keyword length here. */ 2766 if (prefix_length > 79 || prefix_length < 1) 2767 errmsg = "bad keyword"; 2768 2769 /* Expect keyword, compression flag, compression type, language, translated 2770 * keyword (both may be empty but are 0 terminated) then the text, which may 2771 * be empty. 2772 */ 2773 else if (prefix_length + 5 > length) 2774 errmsg = "truncated"; 2775 2776 else if (buffer[prefix_length+1] == 0 || 2777 (buffer[prefix_length+1] == 1 && 2778 buffer[prefix_length+2] == PNG_COMPRESSION_TYPE_BASE)) 2779 { 2780 int compressed = buffer[prefix_length+1] != 0; 2781 png_uint_32 language_offset, translated_keyword_offset; 2782 png_alloc_size_t uncompressed_length = 0; 2783 2784 /* Now the language tag */ 2785 prefix_length += 3; 2786 language_offset = prefix_length; 2787 2788 for (; prefix_length < length && buffer[prefix_length] != 0; 2789 ++prefix_length) 2790 /* Empty loop */ ; 2791 2792 /* WARNING: the length may be invalid here, this is checked below. */ 2793 translated_keyword_offset = ++prefix_length; 2794 2795 for (; prefix_length < length && buffer[prefix_length] != 0; 2796 ++prefix_length) 2797 /* Empty loop */ ; 2798 2799 /* prefix_length should now be at the trailing '\0' of the translated 2800 * keyword, but it may already be over the end. None of this arithmetic 2801 * can overflow because chunks are at most 2^31 bytes long, but on 16-bit 2802 * systems the available allocation may overflow. 2803 */ 2804 ++prefix_length; 2805 2806 if (compressed == 0 && prefix_length <= length) 2807 uncompressed_length = length - prefix_length; 2808 2809 else if (compressed != 0 && prefix_length < length) 2810 { 2811 uncompressed_length = PNG_SIZE_MAX; 2812 2813 /* TODO: at present png_decompress_chunk imposes a single application 2814 * level memory limit, this should be split to different values for 2815 * iCCP and text chunks. 2816 */ 2817 if (png_decompress_chunk(png_ptr, length, prefix_length, 2818 &uncompressed_length, 1/*terminate*/) == Z_STREAM_END) 2819 buffer = png_ptr->read_buffer; 2820 2821 else 2822 errmsg = png_ptr->zstream.msg; 2823 } 2824 2825 else 2826 errmsg = "truncated"; 2827 2828 if (errmsg == NULL) 2829 { 2830 png_text text; 2831 2832 buffer[uncompressed_length+prefix_length] = 0; 2833 2834 if (compressed == 0) 2835 text.compression = PNG_ITXT_COMPRESSION_NONE; 2836 2837 else 2838 text.compression = PNG_ITXT_COMPRESSION_zTXt; 2839 2840 text.key = (png_charp)buffer; 2841 text.lang = (png_charp)buffer + language_offset; 2842 text.lang_key = (png_charp)buffer + translated_keyword_offset; 2843 text.text = (png_charp)buffer + prefix_length; 2844 text.text_length = 0; 2845 text.itxt_length = uncompressed_length; 2846 2847 if (png_set_text_2(png_ptr, info_ptr, &text, 1) != 0) 2848 errmsg = "insufficient memory"; 2849 } 2850 } 2851 2852 else 2853 errmsg = "bad compression info"; 2854 2855 if (errmsg != NULL) 2856 png_chunk_benign_error(png_ptr, errmsg); 2857 } 2858 #endif 2859 2860 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED 2861 /* Utility function for png_handle_unknown; set up png_ptr::unknown_chunk */ 2862 static int 2863 png_cache_unknown_chunk(png_structrp png_ptr, png_uint_32 length) 2864 { 2865 png_alloc_size_t limit = PNG_SIZE_MAX; 2866 2867 if (png_ptr->unknown_chunk.data != NULL) 2868 { 2869 png_free(png_ptr, png_ptr->unknown_chunk.data); 2870 png_ptr->unknown_chunk.data = NULL; 2871 } 2872 2873 # ifdef PNG_SET_USER_LIMITS_SUPPORTED 2874 if (png_ptr->user_chunk_malloc_max > 0 && 2875 png_ptr->user_chunk_malloc_max < limit) 2876 limit = png_ptr->user_chunk_malloc_max; 2877 2878 # elif PNG_USER_CHUNK_MALLOC_MAX > 0 2879 if (PNG_USER_CHUNK_MALLOC_MAX < limit) 2880 limit = PNG_USER_CHUNK_MALLOC_MAX; 2881 # endif 2882 2883 if (length <= limit) 2884 { 2885 PNG_CSTRING_FROM_CHUNK(png_ptr->unknown_chunk.name, png_ptr->chunk_name); 2886 /* The following is safe because of the PNG_SIZE_MAX init above */ 2887 png_ptr->unknown_chunk.size = (size_t)length/*SAFE*/; 2888 /* 'mode' is a flag array, only the bottom four bits matter here */ 2889 png_ptr->unknown_chunk.location = (png_byte)png_ptr->mode/*SAFE*/; 2890 2891 if (length == 0) 2892 png_ptr->unknown_chunk.data = NULL; 2893 2894 else 2895 { 2896 /* Do a 'warn' here - it is handled below. */ 2897 png_ptr->unknown_chunk.data = png_voidcast(png_bytep, 2898 png_malloc_warn(png_ptr, length)); 2899 } 2900 } 2901 2902 if (png_ptr->unknown_chunk.data == NULL && length > 0) 2903 { 2904 /* This is benign because we clean up correctly */ 2905 png_crc_finish(png_ptr, length); 2906 png_chunk_benign_error(png_ptr, "unknown chunk exceeds memory limits"); 2907 return 0; 2908 } 2909 2910 else 2911 { 2912 if (length > 0) 2913 png_crc_read(png_ptr, png_ptr->unknown_chunk.data, length); 2914 png_crc_finish(png_ptr, 0); 2915 return 1; 2916 } 2917 } 2918 #endif /* READ_UNKNOWN_CHUNKS */ 2919 2920 /* Handle an unknown, or known but disabled, chunk */ 2921 void /* PRIVATE */ 2922 png_handle_unknown(png_structrp png_ptr, png_inforp info_ptr, 2923 png_uint_32 length, int keep) 2924 { 2925 int handled = 0; /* the chunk was handled */ 2926 2927 png_debug(1, "in png_handle_unknown"); 2928 2929 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED 2930 /* NOTE: this code is based on the code in libpng-1.4.12 except for fixing 2931 * the bug which meant that setting a non-default behavior for a specific 2932 * chunk would be ignored (the default was always used unless a user 2933 * callback was installed). 2934 * 2935 * 'keep' is the value from the png_chunk_unknown_handling, the setting for 2936 * this specific chunk_name, if PNG_HANDLE_AS_UNKNOWN_SUPPORTED, if not it 2937 * will always be PNG_HANDLE_CHUNK_AS_DEFAULT and it needs to be set here. 2938 * This is just an optimization to avoid multiple calls to the lookup 2939 * function. 2940 */ 2941 # ifndef PNG_HANDLE_AS_UNKNOWN_SUPPORTED 2942 # ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED 2943 keep = png_chunk_unknown_handling(png_ptr, png_ptr->chunk_name); 2944 # endif 2945 # endif 2946 2947 /* One of the following methods will read the chunk or skip it (at least one 2948 * of these is always defined because this is the only way to switch on 2949 * PNG_READ_UNKNOWN_CHUNKS_SUPPORTED) 2950 */ 2951 # ifdef PNG_READ_USER_CHUNKS_SUPPORTED 2952 /* The user callback takes precedence over the chunk keep value, but the 2953 * keep value is still required to validate a save of a critical chunk. 2954 */ 2955 if (png_ptr->read_user_chunk_fn != NULL) 2956 { 2957 if (png_cache_unknown_chunk(png_ptr, length) != 0) 2958 { 2959 /* Callback to user unknown chunk handler */ 2960 int ret = (*(png_ptr->read_user_chunk_fn))(png_ptr, 2961 &png_ptr->unknown_chunk); 2962 2963 /* ret is: 2964 * negative: An error occurred; png_chunk_error will be called. 2965 * zero: The chunk was not handled, the chunk will be discarded 2966 * unless png_set_keep_unknown_chunks has been used to set 2967 * a 'keep' behavior for this particular chunk, in which 2968 * case that will be used. A critical chunk will cause an 2969 * error at this point unless it is to be saved. 2970 * positive: The chunk was handled, libpng will ignore/discard it. 2971 */ 2972 if (ret < 0) 2973 png_chunk_error(png_ptr, "error in user chunk"); 2974 2975 else if (ret == 0) 2976 { 2977 /* If the keep value is 'default' or 'never' override it, but 2978 * still error out on critical chunks unless the keep value is 2979 * 'always' While this is weird it is the behavior in 1.4.12. 2980 * A possible improvement would be to obey the value set for the 2981 * chunk, but this would be an API change that would probably 2982 * damage some applications. 2983 * 2984 * The png_app_warning below catches the case that matters, where 2985 * the application has not set specific save or ignore for this 2986 * chunk or global save or ignore. 2987 */ 2988 if (keep < PNG_HANDLE_CHUNK_IF_SAFE) 2989 { 2990 # ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED 2991 if (png_ptr->unknown_default < PNG_HANDLE_CHUNK_IF_SAFE) 2992 { 2993 png_chunk_warning(png_ptr, "Saving unknown chunk:"); 2994 png_app_warning(png_ptr, 2995 "forcing save of an unhandled chunk;" 2996 " please call png_set_keep_unknown_chunks"); 2997 /* with keep = PNG_HANDLE_CHUNK_IF_SAFE */ 2998 } 2999 # endif 3000 keep = PNG_HANDLE_CHUNK_IF_SAFE; 3001 } 3002 } 3003 3004 else /* chunk was handled */ 3005 { 3006 handled = 1; 3007 /* Critical chunks can be safely discarded at this point. */ 3008 keep = PNG_HANDLE_CHUNK_NEVER; 3009 } 3010 } 3011 3012 else 3013 keep = PNG_HANDLE_CHUNK_NEVER; /* insufficient memory */ 3014 } 3015 3016 else 3017 /* Use the SAVE_UNKNOWN_CHUNKS code or skip the chunk */ 3018 # endif /* READ_USER_CHUNKS */ 3019 3020 # ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED 3021 { 3022 /* keep is currently just the per-chunk setting, if there was no 3023 * setting change it to the global default now (not that this may 3024 * still be AS_DEFAULT) then obtain the cache of the chunk if required, 3025 * if not simply skip the chunk. 3026 */ 3027 if (keep == PNG_HANDLE_CHUNK_AS_DEFAULT) 3028 keep = png_ptr->unknown_default; 3029 3030 if (keep == PNG_HANDLE_CHUNK_ALWAYS || 3031 (keep == PNG_HANDLE_CHUNK_IF_SAFE && 3032 PNG_CHUNK_ANCILLARY(png_ptr->chunk_name))) 3033 { 3034 if (png_cache_unknown_chunk(png_ptr, length) == 0) 3035 keep = PNG_HANDLE_CHUNK_NEVER; 3036 } 3037 3038 else 3039 png_crc_finish(png_ptr, length); 3040 } 3041 # else 3042 # ifndef PNG_READ_USER_CHUNKS_SUPPORTED 3043 # error no method to support READ_UNKNOWN_CHUNKS 3044 # endif 3045 3046 { 3047 /* If here there is no read callback pointer set and no support is 3048 * compiled in to just save the unknown chunks, so simply skip this 3049 * chunk. If 'keep' is something other than AS_DEFAULT or NEVER then 3050 * the app has erroneously asked for unknown chunk saving when there 3051 * is no support. 3052 */ 3053 if (keep > PNG_HANDLE_CHUNK_NEVER) 3054 png_app_error(png_ptr, "no unknown chunk support available"); 3055 3056 png_crc_finish(png_ptr, length); 3057 } 3058 # endif 3059 3060 # ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED 3061 /* Now store the chunk in the chunk list if appropriate, and if the limits 3062 * permit it. 3063 */ 3064 if (keep == PNG_HANDLE_CHUNK_ALWAYS || 3065 (keep == PNG_HANDLE_CHUNK_IF_SAFE && 3066 PNG_CHUNK_ANCILLARY(png_ptr->chunk_name))) 3067 { 3068 # ifdef PNG_USER_LIMITS_SUPPORTED 3069 switch (png_ptr->user_chunk_cache_max) 3070 { 3071 case 2: 3072 png_ptr->user_chunk_cache_max = 1; 3073 png_chunk_benign_error(png_ptr, "no space in chunk cache"); 3074 /* FALLTHROUGH */ 3075 case 1: 3076 /* NOTE: prior to 1.6.0 this case resulted in an unknown critical 3077 * chunk being skipped, now there will be a hard error below. 3078 */ 3079 break; 3080 3081 default: /* not at limit */ 3082 --(png_ptr->user_chunk_cache_max); 3083 /* FALLTHROUGH */ 3084 case 0: /* no limit */ 3085 # endif /* USER_LIMITS */ 3086 /* Here when the limit isn't reached or when limits are compiled 3087 * out; store the chunk. 3088 */ 3089 png_set_unknown_chunks(png_ptr, info_ptr, 3090 &png_ptr->unknown_chunk, 1); 3091 handled = 1; 3092 # ifdef PNG_USER_LIMITS_SUPPORTED 3093 break; 3094 } 3095 # endif 3096 } 3097 # else /* no store support: the chunk must be handled by the user callback */ 3098 PNG_UNUSED(info_ptr) 3099 # endif 3100 3101 /* Regardless of the error handling below the cached data (if any) can be 3102 * freed now. Notice that the data is not freed if there is a png_error, but 3103 * it will be freed by destroy_read_struct. 3104 */ 3105 if (png_ptr->unknown_chunk.data != NULL) 3106 png_free(png_ptr, png_ptr->unknown_chunk.data); 3107 png_ptr->unknown_chunk.data = NULL; 3108 3109 #else /* !PNG_READ_UNKNOWN_CHUNKS_SUPPORTED */ 3110 /* There is no support to read an unknown chunk, so just skip it. */ 3111 png_crc_finish(png_ptr, length); 3112 PNG_UNUSED(info_ptr) 3113 PNG_UNUSED(keep) 3114 #endif /* !READ_UNKNOWN_CHUNKS */ 3115 3116 /* Check for unhandled critical chunks */ 3117 if (handled == 0 && PNG_CHUNK_CRITICAL(png_ptr->chunk_name)) 3118 png_chunk_error(png_ptr, "unhandled critical chunk"); 3119 } 3120 3121 /* This function is called to verify that a chunk name is valid. 3122 * This function can't have the "critical chunk check" incorporated 3123 * into it, since in the future we will need to be able to call user 3124 * functions to handle unknown critical chunks after we check that 3125 * the chunk name itself is valid. 3126 */ 3127 3128 /* Bit hacking: the test for an invalid byte in the 4 byte chunk name is: 3129 * 3130 * ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97)) 3131 */ 3132 3133 void /* PRIVATE */ 3134 png_check_chunk_name(png_const_structrp png_ptr, png_uint_32 chunk_name) 3135 { 3136 int i; 3137 png_uint_32 cn=chunk_name; 3138 3139 png_debug(1, "in png_check_chunk_name"); 3140 3141 for (i=1; i<=4; ++i) 3142 { 3143 int c = cn & 0xff; 3144 3145 if (c < 65 || c > 122 || (c > 90 && c < 97)) 3146 png_chunk_error(png_ptr, "invalid chunk type"); 3147 3148 cn >>= 8; 3149 } 3150 } 3151 3152 void /* PRIVATE */ 3153 png_check_chunk_length(png_const_structrp png_ptr, png_uint_32 length) 3154 { 3155 png_alloc_size_t limit = PNG_UINT_31_MAX; 3156 3157 # ifdef PNG_SET_USER_LIMITS_SUPPORTED 3158 if (png_ptr->user_chunk_malloc_max > 0 && 3159 png_ptr->user_chunk_malloc_max < limit) 3160 limit = png_ptr->user_chunk_malloc_max; 3161 # elif PNG_USER_CHUNK_MALLOC_MAX > 0 3162 if (PNG_USER_CHUNK_MALLOC_MAX < limit) 3163 limit = PNG_USER_CHUNK_MALLOC_MAX; 3164 # endif 3165 if (png_ptr->chunk_name == png_IDAT) 3166 { 3167 png_alloc_size_t idat_limit = PNG_UINT_31_MAX; 3168 size_t row_factor = 3169 (size_t)png_ptr->width 3170 * (size_t)png_ptr->channels 3171 * (png_ptr->bit_depth > 8? 2: 1) 3172 + 1 3173 + (png_ptr->interlaced? 6: 0); 3174 if (png_ptr->height > PNG_UINT_32_MAX/row_factor) 3175 idat_limit = PNG_UINT_31_MAX; 3176 else 3177 idat_limit = png_ptr->height * row_factor; 3178 row_factor = row_factor > 32566? 32566 : row_factor; 3179 idat_limit += 6 + 5*(idat_limit/row_factor+1); /* zlib+deflate overhead */ 3180 idat_limit=idat_limit < PNG_UINT_31_MAX? idat_limit : PNG_UINT_31_MAX; 3181 limit = limit < idat_limit? idat_limit : limit; 3182 } 3183 3184 if (length > limit) 3185 { 3186 png_debug2(0," length = %lu, limit = %lu", 3187 (unsigned long)length,(unsigned long)limit); 3188 png_chunk_error(png_ptr, "chunk data is too large"); 3189 } 3190 } 3191 3192 /* Combines the row recently read in with the existing pixels in the row. This 3193 * routine takes care of alpha and transparency if requested. This routine also 3194 * handles the two methods of progressive display of interlaced images, 3195 * depending on the 'display' value; if 'display' is true then the whole row 3196 * (dp) is filled from the start by replicating the available pixels. If 3197 * 'display' is false only those pixels present in the pass are filled in. 3198 */ 3199 void /* PRIVATE */ 3200 png_combine_row(png_const_structrp png_ptr, png_bytep dp, int display) 3201 { 3202 unsigned int pixel_depth = png_ptr->transformed_pixel_depth; 3203 png_const_bytep sp = png_ptr->row_buf + 1; 3204 png_alloc_size_t row_width = png_ptr->width; 3205 unsigned int pass = png_ptr->pass; 3206 png_bytep end_ptr = 0; 3207 png_byte end_byte = 0; 3208 unsigned int end_mask; 3209 3210 png_debug(1, "in png_combine_row"); 3211 3212 /* Added in 1.5.6: it should not be possible to enter this routine until at 3213 * least one row has been read from the PNG data and transformed. 3214 */ 3215 if (pixel_depth == 0) 3216 png_error(png_ptr, "internal row logic error"); 3217 3218 /* Added in 1.5.4: the pixel depth should match the information returned by 3219 * any call to png_read_update_info at this point. Do not continue if we got 3220 * this wrong. 3221 */ 3222 if (png_ptr->info_rowbytes != 0 && png_ptr->info_rowbytes != 3223 PNG_ROWBYTES(pixel_depth, row_width)) 3224 png_error(png_ptr, "internal row size calculation error"); 3225 3226 /* Don't expect this to ever happen: */ 3227 if (row_width == 0) 3228 png_error(png_ptr, "internal row width error"); 3229 3230 /* Preserve the last byte in cases where only part of it will be overwritten, 3231 * the multiply below may overflow, we don't care because ANSI-C guarantees 3232 * we get the low bits. 3233 */ 3234 end_mask = (pixel_depth * row_width) & 7; 3235 if (end_mask != 0) 3236 { 3237 /* end_ptr == NULL is a flag to say do nothing */ 3238 end_ptr = dp + PNG_ROWBYTES(pixel_depth, row_width) - 1; 3239 end_byte = *end_ptr; 3240 # ifdef PNG_READ_PACKSWAP_SUPPORTED 3241 if ((png_ptr->transformations & PNG_PACKSWAP) != 0) 3242 /* little-endian byte */ 3243 end_mask = (unsigned int)(0xff << end_mask); 3244 3245 else /* big-endian byte */ 3246 # endif 3247 end_mask = 0xff >> end_mask; 3248 /* end_mask is now the bits to *keep* from the destination row */ 3249 } 3250 3251 /* For non-interlaced images this reduces to a memcpy(). A memcpy() 3252 * will also happen if interlacing isn't supported or if the application 3253 * does not call png_set_interlace_handling(). In the latter cases the 3254 * caller just gets a sequence of the unexpanded rows from each interlace 3255 * pass. 3256 */ 3257 #ifdef PNG_READ_INTERLACING_SUPPORTED 3258 if (png_ptr->interlaced != 0 && 3259 (png_ptr->transformations & PNG_INTERLACE) != 0 && 3260 pass < 6 && (display == 0 || 3261 /* The following copies everything for 'display' on passes 0, 2 and 4. */ 3262 (display == 1 && (pass & 1) != 0))) 3263 { 3264 /* Narrow images may have no bits in a pass; the caller should handle 3265 * this, but this test is cheap: 3266 */ 3267 if (row_width <= PNG_PASS_START_COL(pass)) 3268 return; 3269 3270 if (pixel_depth < 8) 3271 { 3272 /* For pixel depths up to 4 bpp the 8-pixel mask can be expanded to fit 3273 * into 32 bits, then a single loop over the bytes using the four byte 3274 * values in the 32-bit mask can be used. For the 'display' option the 3275 * expanded mask may also not require any masking within a byte. To 3276 * make this work the PACKSWAP option must be taken into account - it 3277 * simply requires the pixels to be reversed in each byte. 3278 * 3279 * The 'regular' case requires a mask for each of the first 6 passes, 3280 * the 'display' case does a copy for the even passes in the range 3281 * 0..6. This has already been handled in the test above. 3282 * 3283 * The masks are arranged as four bytes with the first byte to use in 3284 * the lowest bits (little-endian) regardless of the order (PACKSWAP or 3285 * not) of the pixels in each byte. 3286 * 3287 * NOTE: the whole of this logic depends on the caller of this function 3288 * only calling it on rows appropriate to the pass. This function only 3289 * understands the 'x' logic; the 'y' logic is handled by the caller. 3290 * 3291 * The following defines allow generation of compile time constant bit 3292 * masks for each pixel depth and each possibility of swapped or not 3293 * swapped bytes. Pass 'p' is in the range 0..6; 'x', a pixel index, 3294 * is in the range 0..7; and the result is 1 if the pixel is to be 3295 * copied in the pass, 0 if not. 'S' is for the sparkle method, 'B' 3296 * for the block method. 3297 * 3298 * With some compilers a compile time expression of the general form: 3299 * 3300 * (shift >= 32) ? (a >> (shift-32)) : (b >> shift) 3301 * 3302 * Produces warnings with values of 'shift' in the range 33 to 63 3303 * because the right hand side of the ?: expression is evaluated by 3304 * the compiler even though it isn't used. Microsoft Visual C (various 3305 * versions) and the Intel C compiler are known to do this. To avoid 3306 * this the following macros are used in 1.5.6. This is a temporary 3307 * solution to avoid destabilizing the code during the release process. 3308 */ 3309 # if PNG_USE_COMPILE_TIME_MASKS 3310 # define PNG_LSR(x,s) ((x)>>((s) & 0x1f)) 3311 # define PNG_LSL(x,s) ((x)<<((s) & 0x1f)) 3312 # else 3313 # define PNG_LSR(x,s) ((x)>>(s)) 3314 # define PNG_LSL(x,s) ((x)<<(s)) 3315 # endif 3316 # define S_COPY(p,x) (((p)<4 ? PNG_LSR(0x80088822,(3-(p))*8+(7-(x))) :\ 3317 PNG_LSR(0xaa55ff00,(7-(p))*8+(7-(x)))) & 1) 3318 # define B_COPY(p,x) (((p)<4 ? PNG_LSR(0xff0fff33,(3-(p))*8+(7-(x))) :\ 3319 PNG_LSR(0xff55ff00,(7-(p))*8+(7-(x)))) & 1) 3320 3321 /* Return a mask for pass 'p' pixel 'x' at depth 'd'. The mask is 3322 * little endian - the first pixel is at bit 0 - however the extra 3323 * parameter 's' can be set to cause the mask position to be swapped 3324 * within each byte, to match the PNG format. This is done by XOR of 3325 * the shift with 7, 6 or 4 for bit depths 1, 2 and 4. 3326 */ 3327 # define PIXEL_MASK(p,x,d,s) \ 3328 (PNG_LSL(((PNG_LSL(1U,(d)))-1),(((x)*(d))^((s)?8-(d):0)))) 3329 3330 /* Hence generate the appropriate 'block' or 'sparkle' pixel copy mask. 3331 */ 3332 # define S_MASKx(p,x,d,s) (S_COPY(p,x)?PIXEL_MASK(p,x,d,s):0) 3333 # define B_MASKx(p,x,d,s) (B_COPY(p,x)?PIXEL_MASK(p,x,d,s):0) 3334 3335 /* Combine 8 of these to get the full mask. For the 1-bpp and 2-bpp 3336 * cases the result needs replicating, for the 4-bpp case the above 3337 * generates a full 32 bits. 3338 */ 3339 # define MASK_EXPAND(m,d) ((m)*((d)==1?0x01010101:((d)==2?0x00010001:1))) 3340 3341 # define S_MASK(p,d,s) MASK_EXPAND(S_MASKx(p,0,d,s) + S_MASKx(p,1,d,s) +\ 3342 S_MASKx(p,2,d,s) + S_MASKx(p,3,d,s) + S_MASKx(p,4,d,s) +\ 3343 S_MASKx(p,5,d,s) + S_MASKx(p,6,d,s) + S_MASKx(p,7,d,s), d) 3344 3345 # define B_MASK(p,d,s) MASK_EXPAND(B_MASKx(p,0,d,s) + B_MASKx(p,1,d,s) +\ 3346 B_MASKx(p,2,d,s) + B_MASKx(p,3,d,s) + B_MASKx(p,4,d,s) +\ 3347 B_MASKx(p,5,d,s) + B_MASKx(p,6,d,s) + B_MASKx(p,7,d,s), d) 3348 3349 #if PNG_USE_COMPILE_TIME_MASKS 3350 /* Utility macros to construct all the masks for a depth/swap 3351 * combination. The 's' parameter says whether the format is PNG 3352 * (big endian bytes) or not. Only the three odd-numbered passes are 3353 * required for the display/block algorithm. 3354 */ 3355 # define S_MASKS(d,s) { S_MASK(0,d,s), S_MASK(1,d,s), S_MASK(2,d,s),\ 3356 S_MASK(3,d,s), S_MASK(4,d,s), S_MASK(5,d,s) } 3357 3358 # define B_MASKS(d,s) { B_MASK(1,d,s), B_MASK(3,d,s), B_MASK(5,d,s) } 3359 3360 # define DEPTH_INDEX(d) ((d)==1?0:((d)==2?1:2)) 3361 3362 /* Hence the pre-compiled masks indexed by PACKSWAP (or not), depth and 3363 * then pass: 3364 */ 3365 static const png_uint_32 row_mask[2/*PACKSWAP*/][3/*depth*/][6] = 3366 { 3367 /* Little-endian byte masks for PACKSWAP */ 3368 { S_MASKS(1,0), S_MASKS(2,0), S_MASKS(4,0) }, 3369 /* Normal (big-endian byte) masks - PNG format */ 3370 { S_MASKS(1,1), S_MASKS(2,1), S_MASKS(4,1) } 3371 }; 3372 3373 /* display_mask has only three entries for the odd passes, so index by 3374 * pass>>1. 3375 */ 3376 static const png_uint_32 display_mask[2][3][3] = 3377 { 3378 /* Little-endian byte masks for PACKSWAP */ 3379 { B_MASKS(1,0), B_MASKS(2,0), B_MASKS(4,0) }, 3380 /* Normal (big-endian byte) masks - PNG format */ 3381 { B_MASKS(1,1), B_MASKS(2,1), B_MASKS(4,1) } 3382 }; 3383 3384 # define MASK(pass,depth,display,png)\ 3385 ((display)?display_mask[png][DEPTH_INDEX(depth)][pass>>1]:\ 3386 row_mask[png][DEPTH_INDEX(depth)][pass]) 3387 3388 #else /* !PNG_USE_COMPILE_TIME_MASKS */ 3389 /* This is the runtime alternative: it seems unlikely that this will 3390 * ever be either smaller or faster than the compile time approach. 3391 */ 3392 # define MASK(pass,depth,display,png)\ 3393 ((display)?B_MASK(pass,depth,png):S_MASK(pass,depth,png)) 3394 #endif /* !USE_COMPILE_TIME_MASKS */ 3395 3396 /* Use the appropriate mask to copy the required bits. In some cases 3397 * the byte mask will be 0 or 0xff; optimize these cases. row_width is 3398 * the number of pixels, but the code copies bytes, so it is necessary 3399 * to special case the end. 3400 */ 3401 png_uint_32 pixels_per_byte = 8 / pixel_depth; 3402 png_uint_32 mask; 3403 3404 # ifdef PNG_READ_PACKSWAP_SUPPORTED 3405 if ((png_ptr->transformations & PNG_PACKSWAP) != 0) 3406 mask = MASK(pass, pixel_depth, display, 0); 3407 3408 else 3409 # endif 3410 mask = MASK(pass, pixel_depth, display, 1); 3411 3412 for (;;) 3413 { 3414 png_uint_32 m; 3415 3416 /* It doesn't matter in the following if png_uint_32 has more than 3417 * 32 bits because the high bits always match those in m<<24; it is, 3418 * however, essential to use OR here, not +, because of this. 3419 */ 3420 m = mask; 3421 mask = (m >> 8) | (m << 24); /* rotate right to good compilers */ 3422 m &= 0xff; 3423 3424 if (m != 0) /* something to copy */ 3425 { 3426 if (m != 0xff) 3427 *dp = (png_byte)((*dp & ~m) | (*sp & m)); 3428 else 3429 *dp = *sp; 3430 } 3431 3432 /* NOTE: this may overwrite the last byte with garbage if the image 3433 * is not an exact number of bytes wide; libpng has always done 3434 * this. 3435 */ 3436 if (row_width <= pixels_per_byte) 3437 break; /* May need to restore part of the last byte */ 3438 3439 row_width -= pixels_per_byte; 3440 ++dp; 3441 ++sp; 3442 } 3443 } 3444 3445 else /* pixel_depth >= 8 */ 3446 { 3447 unsigned int bytes_to_copy, bytes_to_jump; 3448 3449 /* Validate the depth - it must be a multiple of 8 */ 3450 if (pixel_depth & 7) 3451 png_error(png_ptr, "invalid user transform pixel depth"); 3452 3453 pixel_depth >>= 3; /* now in bytes */ 3454 row_width *= pixel_depth; 3455 3456 /* Regardless of pass number the Adam 7 interlace always results in a 3457 * fixed number of pixels to copy then to skip. There may be a 3458 * different number of pixels to skip at the start though. 3459 */ 3460 { 3461 unsigned int offset = PNG_PASS_START_COL(pass) * pixel_depth; 3462 3463 row_width -= offset; 3464 dp += offset; 3465 sp += offset; 3466 } 3467 3468 /* Work out the bytes to copy. */ 3469 if (display != 0) 3470 { 3471 /* When doing the 'block' algorithm the pixel in the pass gets 3472 * replicated to adjacent pixels. This is why the even (0,2,4,6) 3473 * passes are skipped above - the entire expanded row is copied. 3474 */ 3475 bytes_to_copy = (1<<((6-pass)>>1)) * pixel_depth; 3476 3477 /* But don't allow this number to exceed the actual row width. */ 3478 if (bytes_to_copy > row_width) 3479 bytes_to_copy = (unsigned int)/*SAFE*/row_width; 3480 } 3481 3482 else /* normal row; Adam7 only ever gives us one pixel to copy. */ 3483 bytes_to_copy = pixel_depth; 3484 3485 /* In Adam7 there is a constant offset between where the pixels go. */ 3486 bytes_to_jump = PNG_PASS_COL_OFFSET(pass) * pixel_depth; 3487 3488 /* And simply copy these bytes. Some optimization is possible here, 3489 * depending on the value of 'bytes_to_copy'. Special case the low 3490 * byte counts, which we know to be frequent. 3491 * 3492 * Notice that these cases all 'return' rather than 'break' - this 3493 * avoids an unnecessary test on whether to restore the last byte 3494 * below. 3495 */ 3496 switch (bytes_to_copy) 3497 { 3498 case 1: 3499 for (;;) 3500 { 3501 *dp = *sp; 3502 3503 if (row_width <= bytes_to_jump) 3504 return; 3505 3506 dp += bytes_to_jump; 3507 sp += bytes_to_jump; 3508 row_width -= bytes_to_jump; 3509 } 3510 3511 case 2: 3512 /* There is a possibility of a partial copy at the end here; this 3513 * slows the code down somewhat. 3514 */ 3515 do 3516 { 3517 dp[0] = sp[0]; dp[1] = sp[1]; 3518 3519 if (row_width <= bytes_to_jump) 3520 return; 3521 3522 sp += bytes_to_jump; 3523 dp += bytes_to_jump; 3524 row_width -= bytes_to_jump; 3525 } 3526 while (row_width > 1); 3527 3528 /* And there can only be one byte left at this point: */ 3529 *dp = *sp; 3530 return; 3531 3532 case 3: 3533 /* This can only be the RGB case, so each copy is exactly one 3534 * pixel and it is not necessary to check for a partial copy. 3535 */ 3536 for (;;) 3537 { 3538 dp[0] = sp[0]; dp[1] = sp[1]; dp[2] = sp[2]; 3539 3540 if (row_width <= bytes_to_jump) 3541 return; 3542 3543 sp += bytes_to_jump; 3544 dp += bytes_to_jump; 3545 row_width -= bytes_to_jump; 3546 } 3547 3548 default: 3549 #if PNG_ALIGN_TYPE != PNG_ALIGN_NONE 3550 /* Check for double byte alignment and, if possible, use a 3551 * 16-bit copy. Don't attempt this for narrow images - ones that 3552 * are less than an interlace panel wide. Don't attempt it for 3553 * wide bytes_to_copy either - use the memcpy there. 3554 */ 3555 if (bytes_to_copy < 16 /*else use memcpy*/ && 3556 png_isaligned(dp, png_uint_16) && 3557 png_isaligned(sp, png_uint_16) && 3558 bytes_to_copy % (sizeof (png_uint_16)) == 0 && 3559 bytes_to_jump % (sizeof (png_uint_16)) == 0) 3560 { 3561 /* Everything is aligned for png_uint_16 copies, but try for 3562 * png_uint_32 first. 3563 */ 3564 if (png_isaligned(dp, png_uint_32) && 3565 png_isaligned(sp, png_uint_32) && 3566 bytes_to_copy % (sizeof (png_uint_32)) == 0 && 3567 bytes_to_jump % (sizeof (png_uint_32)) == 0) 3568 { 3569 png_uint_32p dp32 = png_aligncast(png_uint_32p,dp); 3570 png_const_uint_32p sp32 = png_aligncastconst( 3571 png_const_uint_32p, sp); 3572 size_t skip = (bytes_to_jump-bytes_to_copy) / 3573 (sizeof (png_uint_32)); 3574 3575 do 3576 { 3577 size_t c = bytes_to_copy; 3578 do 3579 { 3580 *dp32++ = *sp32++; 3581 c -= (sizeof (png_uint_32)); 3582 } 3583 while (c > 0); 3584 3585 if (row_width <= bytes_to_jump) 3586 return; 3587 3588 dp32 += skip; 3589 sp32 += skip; 3590 row_width -= bytes_to_jump; 3591 } 3592 while (bytes_to_copy <= row_width); 3593 3594 /* Get to here when the row_width truncates the final copy. 3595 * There will be 1-3 bytes left to copy, so don't try the 3596 * 16-bit loop below. 3597 */ 3598 dp = (png_bytep)dp32; 3599 sp = (png_const_bytep)sp32; 3600 do 3601 *dp++ = *sp++; 3602 while (--row_width > 0); 3603 return; 3604 } 3605 3606 /* Else do it in 16-bit quantities, but only if the size is 3607 * not too large. 3608 */ 3609 else 3610 { 3611 png_uint_16p dp16 = png_aligncast(png_uint_16p, dp); 3612 png_const_uint_16p sp16 = png_aligncastconst( 3613 png_const_uint_16p, sp); 3614 size_t skip = (bytes_to_jump-bytes_to_copy) / 3615 (sizeof (png_uint_16)); 3616 3617 do 3618 { 3619 size_t c = bytes_to_copy; 3620 do 3621 { 3622 *dp16++ = *sp16++; 3623 c -= (sizeof (png_uint_16)); 3624 } 3625 while (c > 0); 3626 3627 if (row_width <= bytes_to_jump) 3628 return; 3629 3630 dp16 += skip; 3631 sp16 += skip; 3632 row_width -= bytes_to_jump; 3633 } 3634 while (bytes_to_copy <= row_width); 3635 3636 /* End of row - 1 byte left, bytes_to_copy > row_width: */ 3637 dp = (png_bytep)dp16; 3638 sp = (png_const_bytep)sp16; 3639 do 3640 *dp++ = *sp++; 3641 while (--row_width > 0); 3642 return; 3643 } 3644 } 3645 #endif /* ALIGN_TYPE code */ 3646 3647 /* The true default - use a memcpy: */ 3648 for (;;) 3649 { 3650 memcpy(dp, sp, bytes_to_copy); 3651 3652 if (row_width <= bytes_to_jump) 3653 return; 3654 3655 sp += bytes_to_jump; 3656 dp += bytes_to_jump; 3657 row_width -= bytes_to_jump; 3658 if (bytes_to_copy > row_width) 3659 bytes_to_copy = (unsigned int)/*SAFE*/row_width; 3660 } 3661 } 3662 3663 /* NOT REACHED*/ 3664 } /* pixel_depth >= 8 */ 3665 3666 /* Here if pixel_depth < 8 to check 'end_ptr' below. */ 3667 } 3668 else 3669 #endif /* READ_INTERLACING */ 3670 3671 /* If here then the switch above wasn't used so just memcpy the whole row 3672 * from the temporary row buffer (notice that this overwrites the end of the 3673 * destination row if it is a partial byte.) 3674 */ 3675 memcpy(dp, sp, PNG_ROWBYTES(pixel_depth, row_width)); 3676 3677 /* Restore the overwritten bits from the last byte if necessary. */ 3678 if (end_ptr != NULL) 3679 *end_ptr = (png_byte)((end_byte & end_mask) | (*end_ptr & ~end_mask)); 3680 } 3681 3682 #ifdef PNG_READ_INTERLACING_SUPPORTED 3683 void /* PRIVATE */ 3684 png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass, 3685 png_uint_32 transformations /* Because these may affect the byte layout */) 3686 { 3687 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ 3688 /* Offset to next interlace block */ 3689 static const unsigned int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1}; 3690 3691 png_debug(1, "in png_do_read_interlace"); 3692 if (row != NULL && row_info != NULL) 3693 { 3694 png_uint_32 final_width; 3695 3696 final_width = row_info->width * png_pass_inc[pass]; 3697 3698 switch (row_info->pixel_depth) 3699 { 3700 case 1: 3701 { 3702 png_bytep sp = row + (size_t)((row_info->width - 1) >> 3); 3703 png_bytep dp = row + (size_t)((final_width - 1) >> 3); 3704 unsigned int sshift, dshift; 3705 unsigned int s_start, s_end; 3706 int s_inc; 3707 int jstop = (int)png_pass_inc[pass]; 3708 png_byte v; 3709 png_uint_32 i; 3710 int j; 3711 3712 #ifdef PNG_READ_PACKSWAP_SUPPORTED 3713 if ((transformations & PNG_PACKSWAP) != 0) 3714 { 3715 sshift = ((row_info->width + 7) & 0x07); 3716 dshift = ((final_width + 7) & 0x07); 3717 s_start = 7; 3718 s_end = 0; 3719 s_inc = -1; 3720 } 3721 3722 else 3723 #endif 3724 { 3725 sshift = 7 - ((row_info->width + 7) & 0x07); 3726 dshift = 7 - ((final_width + 7) & 0x07); 3727 s_start = 0; 3728 s_end = 7; 3729 s_inc = 1; 3730 } 3731 3732 for (i = 0; i < row_info->width; i++) 3733 { 3734 v = (png_byte)((*sp >> sshift) & 0x01); 3735 for (j = 0; j < jstop; j++) 3736 { 3737 unsigned int tmp = *dp & (0x7f7f >> (7 - dshift)); 3738 tmp |= (unsigned int)(v << dshift); 3739 *dp = (png_byte)(tmp & 0xff); 3740 3741 if (dshift == s_end) 3742 { 3743 dshift = s_start; 3744 dp--; 3745 } 3746 3747 else 3748 dshift = (unsigned int)((int)dshift + s_inc); 3749 } 3750 3751 if (sshift == s_end) 3752 { 3753 sshift = s_start; 3754 sp--; 3755 } 3756 3757 else 3758 sshift = (unsigned int)((int)sshift + s_inc); 3759 } 3760 break; 3761 } 3762 3763 case 2: 3764 { 3765 png_bytep sp = row + (png_uint_32)((row_info->width - 1) >> 2); 3766 png_bytep dp = row + (png_uint_32)((final_width - 1) >> 2); 3767 unsigned int sshift, dshift; 3768 unsigned int s_start, s_end; 3769 int s_inc; 3770 int jstop = (int)png_pass_inc[pass]; 3771 png_uint_32 i; 3772 3773 #ifdef PNG_READ_PACKSWAP_SUPPORTED 3774 if ((transformations & PNG_PACKSWAP) != 0) 3775 { 3776 sshift = (((row_info->width + 3) & 0x03) << 1); 3777 dshift = (((final_width + 3) & 0x03) << 1); 3778 s_start = 6; 3779 s_end = 0; 3780 s_inc = -2; 3781 } 3782 3783 else 3784 #endif 3785 { 3786 sshift = ((3 - ((row_info->width + 3) & 0x03)) << 1); 3787 dshift = ((3 - ((final_width + 3) & 0x03)) << 1); 3788 s_start = 0; 3789 s_end = 6; 3790 s_inc = 2; 3791 } 3792 3793 for (i = 0; i < row_info->width; i++) 3794 { 3795 png_byte v; 3796 int j; 3797 3798 v = (png_byte)((*sp >> sshift) & 0x03); 3799 for (j = 0; j < jstop; j++) 3800 { 3801 unsigned int tmp = *dp & (0x3f3f >> (6 - dshift)); 3802 tmp |= (unsigned int)(v << dshift); 3803 *dp = (png_byte)(tmp & 0xff); 3804 3805 if (dshift == s_end) 3806 { 3807 dshift = s_start; 3808 dp--; 3809 } 3810 3811 else 3812 dshift = (unsigned int)((int)dshift + s_inc); 3813 } 3814 3815 if (sshift == s_end) 3816 { 3817 sshift = s_start; 3818 sp--; 3819 } 3820 3821 else 3822 sshift = (unsigned int)((int)sshift + s_inc); 3823 } 3824 break; 3825 } 3826 3827 case 4: 3828 { 3829 png_bytep sp = row + (size_t)((row_info->width - 1) >> 1); 3830 png_bytep dp = row + (size_t)((final_width - 1) >> 1); 3831 unsigned int sshift, dshift; 3832 unsigned int s_start, s_end; 3833 int s_inc; 3834 png_uint_32 i; 3835 int jstop = (int)png_pass_inc[pass]; 3836 3837 #ifdef PNG_READ_PACKSWAP_SUPPORTED 3838 if ((transformations & PNG_PACKSWAP) != 0) 3839 { 3840 sshift = (((row_info->width + 1) & 0x01) << 2); 3841 dshift = (((final_width + 1) & 0x01) << 2); 3842 s_start = 4; 3843 s_end = 0; 3844 s_inc = -4; 3845 } 3846 3847 else 3848 #endif 3849 { 3850 sshift = ((1 - ((row_info->width + 1) & 0x01)) << 2); 3851 dshift = ((1 - ((final_width + 1) & 0x01)) << 2); 3852 s_start = 0; 3853 s_end = 4; 3854 s_inc = 4; 3855 } 3856 3857 for (i = 0; i < row_info->width; i++) 3858 { 3859 png_byte v = (png_byte)((*sp >> sshift) & 0x0f); 3860 int j; 3861 3862 for (j = 0; j < jstop; j++) 3863 { 3864 unsigned int tmp = *dp & (0xf0f >> (4 - dshift)); 3865 tmp |= (unsigned int)(v << dshift); 3866 *dp = (png_byte)(tmp & 0xff); 3867 3868 if (dshift == s_end) 3869 { 3870 dshift = s_start; 3871 dp--; 3872 } 3873 3874 else 3875 dshift = (unsigned int)((int)dshift + s_inc); 3876 } 3877 3878 if (sshift == s_end) 3879 { 3880 sshift = s_start; 3881 sp--; 3882 } 3883 3884 else 3885 sshift = (unsigned int)((int)sshift + s_inc); 3886 } 3887 break; 3888 } 3889 3890 default: 3891 { 3892 size_t pixel_bytes = (row_info->pixel_depth >> 3); 3893 3894 png_bytep sp = row + (size_t)(row_info->width - 1) 3895 * pixel_bytes; 3896 3897 png_bytep dp = row + (size_t)(final_width - 1) * pixel_bytes; 3898 3899 int jstop = (int)png_pass_inc[pass]; 3900 png_uint_32 i; 3901 3902 for (i = 0; i < row_info->width; i++) 3903 { 3904 png_byte v[8]; /* SAFE; pixel_depth does not exceed 64 */ 3905 int j; 3906 3907 memcpy(v, sp, pixel_bytes); 3908 3909 for (j = 0; j < jstop; j++) 3910 { 3911 memcpy(dp, v, pixel_bytes); 3912 dp -= pixel_bytes; 3913 } 3914 3915 sp -= pixel_bytes; 3916 } 3917 break; 3918 } 3919 } 3920 3921 row_info->width = final_width; 3922 row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, final_width); 3923 } 3924 #ifndef PNG_READ_PACKSWAP_SUPPORTED 3925 PNG_UNUSED(transformations) /* Silence compiler warning */ 3926 #endif 3927 } 3928 #endif /* READ_INTERLACING */ 3929 3930 static void 3931 png_read_filter_row_sub(png_row_infop row_info, png_bytep row, 3932 png_const_bytep prev_row) 3933 { 3934 size_t i; 3935 size_t istop = row_info->rowbytes; 3936 unsigned int bpp = (row_info->pixel_depth + 7) >> 3; 3937 png_bytep rp = row + bpp; 3938 3939 PNG_UNUSED(prev_row) 3940 3941 for (i = bpp; i < istop; i++) 3942 { 3943 *rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 0xff); 3944 rp++; 3945 } 3946 } 3947 3948 static void 3949 png_read_filter_row_up(png_row_infop row_info, png_bytep row, 3950 png_const_bytep prev_row) 3951 { 3952 size_t i; 3953 size_t istop = row_info->rowbytes; 3954 png_bytep rp = row; 3955 png_const_bytep pp = prev_row; 3956 3957 for (i = 0; i < istop; i++) 3958 { 3959 *rp = (png_byte)(((int)(*rp) + (int)(*pp++)) & 0xff); 3960 rp++; 3961 } 3962 } 3963 3964 static void 3965 png_read_filter_row_avg(png_row_infop row_info, png_bytep row, 3966 png_const_bytep prev_row) 3967 { 3968 size_t i; 3969 png_bytep rp = row; 3970 png_const_bytep pp = prev_row; 3971 unsigned int bpp = (row_info->pixel_depth + 7) >> 3; 3972 size_t istop = row_info->rowbytes - bpp; 3973 3974 for (i = 0; i < bpp; i++) 3975 { 3976 *rp = (png_byte)(((int)(*rp) + 3977 ((int)(*pp++) / 2 )) & 0xff); 3978 3979 rp++; 3980 } 3981 3982 for (i = 0; i < istop; i++) 3983 { 3984 *rp = (png_byte)(((int)(*rp) + 3985 (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff); 3986 3987 rp++; 3988 } 3989 } 3990 3991 static void 3992 png_read_filter_row_paeth_1byte_pixel(png_row_infop row_info, png_bytep row, 3993 png_const_bytep prev_row) 3994 { 3995 png_bytep rp_end = row + row_info->rowbytes; 3996 int a, c; 3997 3998 /* First pixel/byte */ 3999 c = *prev_row++; 4000 a = *row + c; 4001 *row++ = (png_byte)a; 4002 4003 /* Remainder */ 4004 while (row < rp_end) 4005 { 4006 int b, pa, pb, pc, p; 4007 4008 a &= 0xff; /* From previous iteration or start */ 4009 b = *prev_row++; 4010 4011 p = b - c; 4012 pc = a - c; 4013 4014 #ifdef PNG_USE_ABS 4015 pa = abs(p); 4016 pb = abs(pc); 4017 pc = abs(p + pc); 4018 #else 4019 pa = p < 0 ? -p : p; 4020 pb = pc < 0 ? -pc : pc; 4021 pc = (p + pc) < 0 ? -(p + pc) : p + pc; 4022 #endif 4023 4024 /* Find the best predictor, the least of pa, pb, pc favoring the earlier 4025 * ones in the case of a tie. 4026 */ 4027 if (pb < pa) 4028 { 4029 pa = pb; a = b; 4030 } 4031 if (pc < pa) a = c; 4032 4033 /* Calculate the current pixel in a, and move the previous row pixel to c 4034 * for the next time round the loop 4035 */ 4036 c = b; 4037 a += *row; 4038 *row++ = (png_byte)a; 4039 } 4040 } 4041 4042 static void 4043 png_read_filter_row_paeth_multibyte_pixel(png_row_infop row_info, png_bytep row, 4044 png_const_bytep prev_row) 4045 { 4046 unsigned int bpp = (row_info->pixel_depth + 7) >> 3; 4047 png_bytep rp_end = row + bpp; 4048 4049 /* Process the first pixel in the row completely (this is the same as 'up' 4050 * because there is only one candidate predictor for the first row). 4051 */ 4052 while (row < rp_end) 4053 { 4054 int a = *row + *prev_row++; 4055 *row++ = (png_byte)a; 4056 } 4057 4058 /* Remainder */ 4059 rp_end = rp_end + (row_info->rowbytes - bpp); 4060 4061 while (row < rp_end) 4062 { 4063 int a, b, c, pa, pb, pc, p; 4064 4065 c = *(prev_row - bpp); 4066 a = *(row - bpp); 4067 b = *prev_row++; 4068 4069 p = b - c; 4070 pc = a - c; 4071 4072 #ifdef PNG_USE_ABS 4073 pa = abs(p); 4074 pb = abs(pc); 4075 pc = abs(p + pc); 4076 #else 4077 pa = p < 0 ? -p : p; 4078 pb = pc < 0 ? -pc : pc; 4079 pc = (p + pc) < 0 ? -(p + pc) : p + pc; 4080 #endif 4081 4082 if (pb < pa) 4083 { 4084 pa = pb; a = b; 4085 } 4086 if (pc < pa) a = c; 4087 4088 a += *row; 4089 *row++ = (png_byte)a; 4090 } 4091 } 4092 4093 static void 4094 png_init_filter_functions(png_structrp pp) 4095 /* This function is called once for every PNG image (except for PNG images 4096 * that only use PNG_FILTER_VALUE_NONE for all rows) to set the 4097 * implementations required to reverse the filtering of PNG rows. Reversing 4098 * the filter is the first transformation performed on the row data. It is 4099 * performed in place, therefore an implementation can be selected based on 4100 * the image pixel format. If the implementation depends on image width then 4101 * take care to ensure that it works correctly if the image is interlaced - 4102 * interlacing causes the actual row width to vary. 4103 */ 4104 { 4105 unsigned int bpp = (pp->pixel_depth + 7) >> 3; 4106 4107 pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub; 4108 pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up; 4109 pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg; 4110 if (bpp == 1) 4111 pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = 4112 png_read_filter_row_paeth_1byte_pixel; 4113 else 4114 pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = 4115 png_read_filter_row_paeth_multibyte_pixel; 4116 4117 #ifdef PNG_FILTER_OPTIMIZATIONS 4118 /* To use this define PNG_FILTER_OPTIMIZATIONS as the name of a function to 4119 * call to install hardware optimizations for the above functions; simply 4120 * replace whatever elements of the pp->read_filter[] array with a hardware 4121 * specific (or, for that matter, generic) optimization. 4122 * 4123 * To see an example of this examine what configure.ac does when 4124 * --enable-arm-neon is specified on the command line. 4125 */ 4126 PNG_FILTER_OPTIMIZATIONS(pp, bpp); 4127 #endif 4128 } 4129 4130 void /* PRIVATE */ 4131 png_read_filter_row(png_structrp pp, png_row_infop row_info, png_bytep row, 4132 png_const_bytep prev_row, int filter) 4133 { 4134 /* OPTIMIZATION: DO NOT MODIFY THIS FUNCTION, instead #define 4135 * PNG_FILTER_OPTIMIZATIONS to a function that overrides the generic 4136 * implementations. See png_init_filter_functions above. 4137 */ 4138 if (filter > PNG_FILTER_VALUE_NONE && filter < PNG_FILTER_VALUE_LAST) 4139 { 4140 if (pp->read_filter[0] == NULL) 4141 png_init_filter_functions(pp); 4142 4143 pp->read_filter[filter-1](row_info, row, prev_row); 4144 } 4145 } 4146 4147 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED 4148 void /* PRIVATE */ 4149 png_read_IDAT_data(png_structrp png_ptr, png_bytep output, 4150 png_alloc_size_t avail_out) 4151 { 4152 /* Loop reading IDATs and decompressing the result into output[avail_out] */ 4153 png_ptr->zstream.next_out = output; 4154 png_ptr->zstream.avail_out = 0; /* safety: set below */ 4155 4156 if (output == NULL) 4157 avail_out = 0; 4158 4159 do 4160 { 4161 int ret; 4162 png_byte tmpbuf[PNG_INFLATE_BUF_SIZE]; 4163 4164 if (png_ptr->zstream.avail_in == 0) 4165 { 4166 uInt avail_in; 4167 png_bytep buffer; 4168 4169 while (png_ptr->idat_size == 0) 4170 { 4171 png_crc_finish(png_ptr, 0); 4172 4173 png_ptr->idat_size = png_read_chunk_header(png_ptr); 4174 /* This is an error even in the 'check' case because the code just 4175 * consumed a non-IDAT header. 4176 */ 4177 if (png_ptr->chunk_name != png_IDAT) 4178 png_error(png_ptr, "Not enough image data"); 4179 } 4180 4181 avail_in = png_ptr->IDAT_read_size; 4182 4183 if (avail_in > png_ptr->idat_size) 4184 avail_in = (uInt)png_ptr->idat_size; 4185 4186 /* A PNG with a gradually increasing IDAT size will defeat this attempt 4187 * to minimize memory usage by causing lots of re-allocs, but 4188 * realistically doing IDAT_read_size re-allocs is not likely to be a 4189 * big problem. 4190 */ 4191 buffer = png_read_buffer(png_ptr, avail_in, 0/*error*/); 4192 4193 png_crc_read(png_ptr, buffer, avail_in); 4194 png_ptr->idat_size -= avail_in; 4195 4196 png_ptr->zstream.next_in = buffer; 4197 png_ptr->zstream.avail_in = avail_in; 4198 } 4199 4200 /* And set up the output side. */ 4201 if (output != NULL) /* standard read */ 4202 { 4203 uInt out = ZLIB_IO_MAX; 4204 4205 if (out > avail_out) 4206 out = (uInt)avail_out; 4207 4208 avail_out -= out; 4209 png_ptr->zstream.avail_out = out; 4210 } 4211 4212 else /* after last row, checking for end */ 4213 { 4214 png_ptr->zstream.next_out = tmpbuf; 4215 png_ptr->zstream.avail_out = (sizeof tmpbuf); 4216 } 4217 4218 /* Use NO_FLUSH; this gives zlib the maximum opportunity to optimize the 4219 * process. If the LZ stream is truncated the sequential reader will 4220 * terminally damage the stream, above, by reading the chunk header of the 4221 * following chunk (it then exits with png_error). 4222 * 4223 * TODO: deal more elegantly with truncated IDAT lists. 4224 */ 4225 ret = PNG_INFLATE(png_ptr, Z_NO_FLUSH); 4226 4227 /* Take the unconsumed output back. */ 4228 if (output != NULL) 4229 avail_out += png_ptr->zstream.avail_out; 4230 4231 else /* avail_out counts the extra bytes */ 4232 avail_out += (sizeof tmpbuf) - png_ptr->zstream.avail_out; 4233 4234 png_ptr->zstream.avail_out = 0; 4235 4236 if (ret == Z_STREAM_END) 4237 { 4238 /* Do this for safety; we won't read any more into this row. */ 4239 png_ptr->zstream.next_out = NULL; 4240 4241 png_ptr->mode |= PNG_AFTER_IDAT; 4242 png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED; 4243 4244 if (png_ptr->zstream.avail_in > 0 || png_ptr->idat_size > 0) 4245 png_chunk_benign_error(png_ptr, "Extra compressed data"); 4246 break; 4247 } 4248 4249 if (ret != Z_OK) 4250 { 4251 png_zstream_error(png_ptr, ret); 4252 4253 if (output != NULL) 4254 png_chunk_error(png_ptr, png_ptr->zstream.msg); 4255 4256 else /* checking */ 4257 { 4258 png_chunk_benign_error(png_ptr, png_ptr->zstream.msg); 4259 return; 4260 } 4261 } 4262 } while (avail_out > 0); 4263 4264 if (avail_out > 0) 4265 { 4266 /* The stream ended before the image; this is the same as too few IDATs so 4267 * should be handled the same way. 4268 */ 4269 if (output != NULL) 4270 png_error(png_ptr, "Not enough image data"); 4271 4272 else /* the deflate stream contained extra data */ 4273 png_chunk_benign_error(png_ptr, "Too much image data"); 4274 } 4275 } 4276 4277 void /* PRIVATE */ 4278 png_read_finish_IDAT(png_structrp png_ptr) 4279 { 4280 /* We don't need any more data and the stream should have ended, however the 4281 * LZ end code may actually not have been processed. In this case we must 4282 * read it otherwise stray unread IDAT data or, more likely, an IDAT chunk 4283 * may still remain to be consumed. 4284 */ 4285 if ((png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0) 4286 { 4287 /* The NULL causes png_read_IDAT_data to swallow any remaining bytes in 4288 * the compressed stream, but the stream may be damaged too, so even after 4289 * this call we may need to terminate the zstream ownership. 4290 */ 4291 png_read_IDAT_data(png_ptr, NULL, 0); 4292 png_ptr->zstream.next_out = NULL; /* safety */ 4293 4294 /* Now clear everything out for safety; the following may not have been 4295 * done. 4296 */ 4297 if ((png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0) 4298 { 4299 png_ptr->mode |= PNG_AFTER_IDAT; 4300 png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED; 4301 } 4302 } 4303 4304 /* If the zstream has not been released do it now *and* terminate the reading 4305 * of the final IDAT chunk. 4306 */ 4307 if (png_ptr->zowner == png_IDAT) 4308 { 4309 /* Always do this; the pointers otherwise point into the read buffer. */ 4310 png_ptr->zstream.next_in = NULL; 4311 png_ptr->zstream.avail_in = 0; 4312 4313 /* Now we no longer own the zstream. */ 4314 png_ptr->zowner = 0; 4315 4316 /* The slightly weird semantics of the sequential IDAT reading is that we 4317 * are always in or at the end of an IDAT chunk, so we always need to do a 4318 * crc_finish here. If idat_size is non-zero we also need to read the 4319 * spurious bytes at the end of the chunk now. 4320 */ 4321 (void)png_crc_finish(png_ptr, png_ptr->idat_size); 4322 } 4323 } 4324 4325 void /* PRIVATE */ 4326 png_read_finish_row(png_structrp png_ptr) 4327 { 4328 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ 4329 4330 /* Start of interlace block */ 4331 static const png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0}; 4332 4333 /* Offset to next interlace block */ 4334 static const png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1}; 4335 4336 /* Start of interlace block in the y direction */ 4337 static const png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1}; 4338 4339 /* Offset to next interlace block in the y direction */ 4340 static const png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2}; 4341 4342 png_debug(1, "in png_read_finish_row"); 4343 png_ptr->row_number++; 4344 if (png_ptr->row_number < png_ptr->num_rows) 4345 return; 4346 4347 if (png_ptr->interlaced != 0) 4348 { 4349 png_ptr->row_number = 0; 4350 4351 /* TO DO: don't do this if prev_row isn't needed (requires 4352 * read-ahead of the next row's filter byte. 4353 */ 4354 memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1); 4355 4356 do 4357 { 4358 png_ptr->pass++; 4359 4360 if (png_ptr->pass >= 7) 4361 break; 4362 4363 png_ptr->iwidth = (png_ptr->width + 4364 png_pass_inc[png_ptr->pass] - 1 - 4365 png_pass_start[png_ptr->pass]) / 4366 png_pass_inc[png_ptr->pass]; 4367 4368 if ((png_ptr->transformations & PNG_INTERLACE) == 0) 4369 { 4370 png_ptr->num_rows = (png_ptr->height + 4371 png_pass_yinc[png_ptr->pass] - 1 - 4372 png_pass_ystart[png_ptr->pass]) / 4373 png_pass_yinc[png_ptr->pass]; 4374 } 4375 4376 else /* if (png_ptr->transformations & PNG_INTERLACE) */ 4377 break; /* libpng deinterlacing sees every row */ 4378 4379 } while (png_ptr->num_rows == 0 || png_ptr->iwidth == 0); 4380 4381 if (png_ptr->pass < 7) 4382 return; 4383 } 4384 4385 /* Here after at the end of the last row of the last pass. */ 4386 png_read_finish_IDAT(png_ptr); 4387 } 4388 #endif /* SEQUENTIAL_READ */ 4389 4390 void /* PRIVATE */ 4391 png_read_start_row(png_structrp png_ptr) 4392 { 4393 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ 4394 4395 /* Start of interlace block */ 4396 static const png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0}; 4397 4398 /* Offset to next interlace block */ 4399 static const png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1}; 4400 4401 /* Start of interlace block in the y direction */ 4402 static const png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1}; 4403 4404 /* Offset to next interlace block in the y direction */ 4405 static const png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2}; 4406 4407 unsigned int max_pixel_depth; 4408 size_t row_bytes; 4409 4410 png_debug(1, "in png_read_start_row"); 4411 4412 #ifdef PNG_READ_TRANSFORMS_SUPPORTED 4413 png_init_read_transformations(png_ptr); 4414 #endif 4415 if (png_ptr->interlaced != 0) 4416 { 4417 if ((png_ptr->transformations & PNG_INTERLACE) == 0) 4418 png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 - 4419 png_pass_ystart[0]) / png_pass_yinc[0]; 4420 4421 else 4422 png_ptr->num_rows = png_ptr->height; 4423 4424 png_ptr->iwidth = (png_ptr->width + 4425 png_pass_inc[png_ptr->pass] - 1 - 4426 png_pass_start[png_ptr->pass]) / 4427 png_pass_inc[png_ptr->pass]; 4428 } 4429 4430 else 4431 { 4432 png_ptr->num_rows = png_ptr->height; 4433 png_ptr->iwidth = png_ptr->width; 4434 } 4435 4436 max_pixel_depth = (unsigned int)png_ptr->pixel_depth; 4437 4438 /* WARNING: * png_read_transform_info (pngrtran.c) performs a simpler set of 4439 * calculations to calculate the final pixel depth, then 4440 * png_do_read_transforms actually does the transforms. This means that the 4441 * code which effectively calculates this value is actually repeated in three 4442 * separate places. They must all match. Innocent changes to the order of 4443 * transformations can and will break libpng in a way that causes memory 4444 * overwrites. 4445 * 4446 * TODO: fix this. 4447 */ 4448 #ifdef PNG_READ_PACK_SUPPORTED 4449 if ((png_ptr->transformations & PNG_PACK) != 0 && png_ptr->bit_depth < 8) 4450 max_pixel_depth = 8; 4451 #endif 4452 4453 #ifdef PNG_READ_EXPAND_SUPPORTED 4454 if ((png_ptr->transformations & PNG_EXPAND) != 0) 4455 { 4456 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) 4457 { 4458 if (png_ptr->num_trans != 0) 4459 max_pixel_depth = 32; 4460 4461 else 4462 max_pixel_depth = 24; 4463 } 4464 4465 else if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY) 4466 { 4467 if (max_pixel_depth < 8) 4468 max_pixel_depth = 8; 4469 4470 if (png_ptr->num_trans != 0) 4471 max_pixel_depth *= 2; 4472 } 4473 4474 else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB) 4475 { 4476 if (png_ptr->num_trans != 0) 4477 { 4478 max_pixel_depth *= 4; 4479 max_pixel_depth /= 3; 4480 } 4481 } 4482 } 4483 #endif 4484 4485 #ifdef PNG_READ_EXPAND_16_SUPPORTED 4486 if ((png_ptr->transformations & PNG_EXPAND_16) != 0) 4487 { 4488 # ifdef PNG_READ_EXPAND_SUPPORTED 4489 /* In fact it is an error if it isn't supported, but checking is 4490 * the safe way. 4491 */ 4492 if ((png_ptr->transformations & PNG_EXPAND) != 0) 4493 { 4494 if (png_ptr->bit_depth < 16) 4495 max_pixel_depth *= 2; 4496 } 4497 else 4498 # endif 4499 png_ptr->transformations &= ~PNG_EXPAND_16; 4500 } 4501 #endif 4502 4503 #ifdef PNG_READ_FILLER_SUPPORTED 4504 if ((png_ptr->transformations & (PNG_FILLER)) != 0) 4505 { 4506 if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY) 4507 { 4508 if (max_pixel_depth <= 8) 4509 max_pixel_depth = 16; 4510 4511 else 4512 max_pixel_depth = 32; 4513 } 4514 4515 else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB || 4516 png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) 4517 { 4518 if (max_pixel_depth <= 32) 4519 max_pixel_depth = 32; 4520 4521 else 4522 max_pixel_depth = 64; 4523 } 4524 } 4525 #endif 4526 4527 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED 4528 if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0) 4529 { 4530 if ( 4531 #ifdef PNG_READ_EXPAND_SUPPORTED 4532 (png_ptr->num_trans != 0 && 4533 (png_ptr->transformations & PNG_EXPAND) != 0) || 4534 #endif 4535 #ifdef PNG_READ_FILLER_SUPPORTED 4536 (png_ptr->transformations & (PNG_FILLER)) != 0 || 4537 #endif 4538 png_ptr->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) 4539 { 4540 if (max_pixel_depth <= 16) 4541 max_pixel_depth = 32; 4542 4543 else 4544 max_pixel_depth = 64; 4545 } 4546 4547 else 4548 { 4549 if (max_pixel_depth <= 8) 4550 { 4551 if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA) 4552 max_pixel_depth = 32; 4553 4554 else 4555 max_pixel_depth = 24; 4556 } 4557 4558 else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA) 4559 max_pixel_depth = 64; 4560 4561 else 4562 max_pixel_depth = 48; 4563 } 4564 } 4565 #endif 4566 4567 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) && \ 4568 defined(PNG_USER_TRANSFORM_PTR_SUPPORTED) 4569 if ((png_ptr->transformations & PNG_USER_TRANSFORM) != 0) 4570 { 4571 unsigned int user_pixel_depth = png_ptr->user_transform_depth * 4572 png_ptr->user_transform_channels; 4573 4574 if (user_pixel_depth > max_pixel_depth) 4575 max_pixel_depth = user_pixel_depth; 4576 } 4577 #endif 4578 4579 /* This value is stored in png_struct and double checked in the row read 4580 * code. 4581 */ 4582 png_ptr->maximum_pixel_depth = (png_byte)max_pixel_depth; 4583 png_ptr->transformed_pixel_depth = 0; /* calculated on demand */ 4584 4585 /* Align the width on the next larger 8 pixels. Mainly used 4586 * for interlacing 4587 */ 4588 row_bytes = ((png_ptr->width + 7) & ~((png_uint_32)7)); 4589 /* Calculate the maximum bytes needed, adding a byte and a pixel 4590 * for safety's sake 4591 */ 4592 row_bytes = PNG_ROWBYTES(max_pixel_depth, row_bytes) + 4593 1 + ((max_pixel_depth + 7) >> 3U); 4594 4595 #ifdef PNG_MAX_MALLOC_64K 4596 if (row_bytes > (png_uint_32)65536L) 4597 png_error(png_ptr, "This image requires a row greater than 64KB"); 4598 #endif 4599 4600 if (row_bytes + 48 > png_ptr->old_big_row_buf_size) 4601 { 4602 png_free(png_ptr, png_ptr->big_row_buf); 4603 png_free(png_ptr, png_ptr->big_prev_row); 4604 4605 if (png_ptr->interlaced != 0) 4606 png_ptr->big_row_buf = (png_bytep)png_calloc(png_ptr, 4607 row_bytes + 48); 4608 4609 else 4610 png_ptr->big_row_buf = (png_bytep)png_malloc(png_ptr, row_bytes + 48); 4611 4612 png_ptr->big_prev_row = (png_bytep)png_malloc(png_ptr, row_bytes + 48); 4613 4614 #ifdef PNG_ALIGNED_MEMORY_SUPPORTED 4615 /* Use 16-byte aligned memory for row_buf with at least 16 bytes 4616 * of padding before and after row_buf; treat prev_row similarly. 4617 * NOTE: the alignment is to the start of the pixels, one beyond the start 4618 * of the buffer, because of the filter byte. Prior to libpng 1.5.6 this 4619 * was incorrect; the filter byte was aligned, which had the exact 4620 * opposite effect of that intended. 4621 */ 4622 { 4623 png_bytep temp = png_ptr->big_row_buf + 32; 4624 int extra = (int)((temp - (png_bytep)0) & 0x0f); 4625 png_ptr->row_buf = temp - extra - 1/*filter byte*/; 4626 4627 temp = png_ptr->big_prev_row + 32; 4628 extra = (int)((temp - (png_bytep)0) & 0x0f); 4629 png_ptr->prev_row = temp - extra - 1/*filter byte*/; 4630 } 4631 4632 #else 4633 /* Use 31 bytes of padding before and 17 bytes after row_buf. */ 4634 png_ptr->row_buf = png_ptr->big_row_buf + 31; 4635 png_ptr->prev_row = png_ptr->big_prev_row + 31; 4636 #endif 4637 png_ptr->old_big_row_buf_size = row_bytes + 48; 4638 } 4639 4640 #ifdef PNG_MAX_MALLOC_64K 4641 if (png_ptr->rowbytes > 65535) 4642 png_error(png_ptr, "This image requires a row greater than 64KB"); 4643 4644 #endif 4645 if (png_ptr->rowbytes > (PNG_SIZE_MAX - 1)) 4646 png_error(png_ptr, "Row has too many bytes to allocate in memory"); 4647 4648 memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1); 4649 4650 png_debug1(3, "width = %u,", png_ptr->width); 4651 png_debug1(3, "height = %u,", png_ptr->height); 4652 png_debug1(3, "iwidth = %u,", png_ptr->iwidth); 4653 png_debug1(3, "num_rows = %u,", png_ptr->num_rows); 4654 png_debug1(3, "rowbytes = %lu,", (unsigned long)png_ptr->rowbytes); 4655 png_debug1(3, "irowbytes = %lu", 4656 (unsigned long)PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->iwidth) + 1); 4657 4658 /* The sequential reader needs a buffer for IDAT, but the progressive reader 4659 * does not, so free the read buffer now regardless; the sequential reader 4660 * reallocates it on demand. 4661 */ 4662 if (png_ptr->read_buffer != NULL) 4663 { 4664 png_bytep buffer = png_ptr->read_buffer; 4665 4666 png_ptr->read_buffer_size = 0; 4667 png_ptr->read_buffer = NULL; 4668 png_free(png_ptr, buffer); 4669 } 4670 4671 /* Finally claim the zstream for the inflate of the IDAT data, use the bits 4672 * value from the stream (note that this will result in a fatal error if the 4673 * IDAT stream has a bogus deflate header window_bits value, but this should 4674 * not be happening any longer!) 4675 */ 4676 if (png_inflate_claim(png_ptr, png_IDAT) != Z_OK) 4677 png_error(png_ptr, png_ptr->zstream.msg); 4678 4679 png_ptr->flags |= PNG_FLAG_ROW_INIT; 4680 } 4681 #endif /* READ */ 4682