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