1 /* pngrutil.c - utilities to read a PNG file 2 * 3 * Last changed in libpng 1.6.3 [July 18, 2013] 4 * Copyright (c) 1998-2013 Glenn Randers-Pehrson 5 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) 6 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) 7 * 8 * This code is released under the libpng license. 9 * For conditions of distribution and use, see the disclaimer 10 * and license in png.h 11 * 12 * This file contains routines that are only called from within 13 * libpng itself during the course of reading an image. 14 */ 15 16 #include "pngpriv.h" 17 18 #ifdef PNG_READ_SUPPORTED 19 20 png_uint_32 PNGAPI 21 png_get_uint_31(png_const_structrp png_ptr, png_const_bytep buf) 22 { 23 png_uint_32 uval = png_get_uint_32(buf); 24 25 if (uval > PNG_UINT_31_MAX) 26 png_error(png_ptr, "PNG unsigned integer out of range"); 27 28 return (uval); 29 } 30 31 #if defined(PNG_READ_gAMA_SUPPORTED) || defined(PNG_READ_cHRM_SUPPORTED) 32 /* The following is a variation on the above for use with the fixed 33 * point values used for gAMA and cHRM. Instead of png_error it 34 * issues a warning and returns (-1) - an invalid value because both 35 * gAMA and cHRM use *unsigned* integers for fixed point values. 36 */ 37 #define PNG_FIXED_ERROR (-1) 38 39 static png_fixed_point /* PRIVATE */ 40 png_get_fixed_point(png_structrp png_ptr, png_const_bytep buf) 41 { 42 png_uint_32 uval = png_get_uint_32(buf); 43 44 if (uval <= PNG_UINT_31_MAX) 45 return (png_fixed_point)uval; /* known to be in range */ 46 47 /* The caller can turn off the warning by passing NULL. */ 48 if (png_ptr != NULL) 49 png_warning(png_ptr, "PNG fixed point integer out of range"); 50 51 return PNG_FIXED_ERROR; 52 } 53 #endif 54 55 #ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED 56 /* NOTE: the read macros will obscure these definitions, so that if 57 * PNG_USE_READ_MACROS is set the library will not use them internally, 58 * but the APIs will still be available externally. 59 * 60 * The parentheses around "PNGAPI function_name" in the following three 61 * functions are necessary because they allow the macros to co-exist with 62 * these (unused but exported) functions. 63 */ 64 65 /* Grab an unsigned 32-bit integer from a buffer in big-endian format. */ 66 png_uint_32 (PNGAPI 67 png_get_uint_32)(png_const_bytep buf) 68 { 69 png_uint_32 uval = 70 ((png_uint_32)(*(buf )) << 24) + 71 ((png_uint_32)(*(buf + 1)) << 16) + 72 ((png_uint_32)(*(buf + 2)) << 8) + 73 ((png_uint_32)(*(buf + 3)) ) ; 74 75 return uval; 76 } 77 78 /* Grab a signed 32-bit integer from a buffer in big-endian format. The 79 * data is stored in the PNG file in two's complement format and there 80 * is no guarantee that a 'png_int_32' is exactly 32 bits, therefore 81 * the following code does a two's complement to native conversion. 82 */ 83 png_int_32 (PNGAPI 84 png_get_int_32)(png_const_bytep buf) 85 { 86 png_uint_32 uval = png_get_uint_32(buf); 87 if ((uval & 0x80000000) == 0) /* non-negative */ 88 return uval; 89 90 uval = (uval ^ 0xffffffff) + 1; /* 2's complement: -x = ~x+1 */ 91 return -(png_int_32)uval; 92 } 93 94 /* Grab an unsigned 16-bit integer from a buffer in big-endian format. */ 95 png_uint_16 (PNGAPI 96 png_get_uint_16)(png_const_bytep buf) 97 { 98 /* ANSI-C requires an int value to accomodate at least 16 bits so this 99 * works and allows the compiler not to worry about possible narrowing 100 * on 32 bit systems. (Pre-ANSI systems did not make integers smaller 101 * than 16 bits either.) 102 */ 103 unsigned int val = 104 ((unsigned int)(*buf) << 8) + 105 ((unsigned int)(*(buf + 1))); 106 107 return (png_uint_16)val; 108 } 109 110 #endif /* PNG_READ_INT_FUNCTIONS_SUPPORTED */ 111 112 /* Read and check the PNG file signature */ 113 void /* PRIVATE */ 114 png_read_sig(png_structrp png_ptr, png_inforp info_ptr) 115 { 116 png_size_t num_checked, num_to_check; 117 118 /* Exit if the user application does not expect a signature. */ 119 if (png_ptr->sig_bytes >= 8) 120 return; 121 122 num_checked = png_ptr->sig_bytes; 123 num_to_check = 8 - num_checked; 124 125 #ifdef PNG_IO_STATE_SUPPORTED 126 png_ptr->io_state = PNG_IO_READING | PNG_IO_SIGNATURE; 127 #endif 128 129 /* The signature must be serialized in a single I/O call. */ 130 png_read_data(png_ptr, &(info_ptr->signature[num_checked]), num_to_check); 131 png_ptr->sig_bytes = 8; 132 133 if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check)) 134 { 135 if (num_checked < 4 && 136 png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4)) 137 png_error(png_ptr, "Not a PNG file"); 138 else 139 png_error(png_ptr, "PNG file corrupted by ASCII conversion"); 140 } 141 if (num_checked < 3) 142 png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE; 143 } 144 145 /* Read the chunk header (length + type name). 146 * Put the type name into png_ptr->chunk_name, and return the length. 147 */ 148 png_uint_32 /* PRIVATE */ 149 png_read_chunk_header(png_structrp png_ptr) 150 { 151 png_byte buf[8]; 152 png_uint_32 length; 153 154 #ifdef PNG_IO_STATE_SUPPORTED 155 png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_HDR; 156 #endif 157 158 /* Read the length and the chunk name. 159 * This must be performed in a single I/O call. 160 */ 161 png_read_data(png_ptr, buf, 8); 162 length = png_get_uint_31(png_ptr, buf); 163 164 /* Put the chunk name into png_ptr->chunk_name. */ 165 png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(buf+4); 166 167 png_debug2(0, "Reading %lx chunk, length = %lu", 168 (unsigned long)png_ptr->chunk_name, (unsigned long)length); 169 170 /* Reset the crc and run it over the chunk name. */ 171 png_reset_crc(png_ptr); 172 png_calculate_crc(png_ptr, buf + 4, 4); 173 174 /* Check to see if chunk name is valid. */ 175 png_check_chunk_name(png_ptr, png_ptr->chunk_name); 176 177 #ifdef PNG_IO_STATE_SUPPORTED 178 png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_DATA; 179 #endif 180 181 return length; 182 } 183 184 /* Read data, and (optionally) run it through the CRC. */ 185 void /* PRIVATE */ 186 png_crc_read(png_structrp png_ptr, png_bytep buf, png_uint_32 length) 187 { 188 if (png_ptr == NULL) 189 return; 190 191 png_read_data(png_ptr, buf, length); 192 png_calculate_crc(png_ptr, buf, length); 193 } 194 195 /* Optionally skip data and then check the CRC. Depending on whether we 196 * are reading an ancillary or critical chunk, and how the program has set 197 * things up, we may calculate the CRC on the data and print a message. 198 * Returns '1' if there was a CRC error, '0' otherwise. 199 */ 200 int /* PRIVATE */ 201 png_crc_finish(png_structrp png_ptr, png_uint_32 skip) 202 { 203 /* The size of the local buffer for inflate is a good guess as to a 204 * reasonable size to use for buffering reads from the application. 205 */ 206 while (skip > 0) 207 { 208 png_uint_32 len; 209 png_byte tmpbuf[PNG_INFLATE_BUF_SIZE]; 210 211 len = (sizeof tmpbuf); 212 if (len > skip) 213 len = skip; 214 skip -= len; 215 216 png_crc_read(png_ptr, tmpbuf, len); 217 } 218 219 if (png_crc_error(png_ptr)) 220 { 221 if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name) ? 222 !(png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) : 223 (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_USE)) 224 { 225 png_chunk_warning(png_ptr, "CRC error"); 226 } 227 228 else 229 { 230 png_chunk_benign_error(png_ptr, "CRC error"); 231 return (0); 232 } 233 234 return (1); 235 } 236 237 return (0); 238 } 239 240 /* Compare the CRC stored in the PNG file with that calculated by libpng from 241 * the data it has read thus far. 242 */ 243 int /* PRIVATE */ 244 png_crc_error(png_structrp png_ptr) 245 { 246 png_byte crc_bytes[4]; 247 png_uint_32 crc; 248 int need_crc = 1; 249 250 if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name)) 251 { 252 if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) == 253 (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN)) 254 need_crc = 0; 255 } 256 257 else /* critical */ 258 { 259 if (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE) 260 need_crc = 0; 261 } 262 263 #ifdef PNG_IO_STATE_SUPPORTED 264 png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_CRC; 265 #endif 266 267 /* The chunk CRC must be serialized in a single I/O call. */ 268 png_read_data(png_ptr, crc_bytes, 4); 269 270 if (need_crc) 271 { 272 crc = png_get_uint_32(crc_bytes); 273 return ((int)(crc != png_ptr->crc)); 274 } 275 276 else 277 return (0); 278 } 279 280 /* Manage the read buffer; this simply reallocates the buffer if it is not small 281 * enough (or if it is not allocated). The routine returns a pointer to the 282 * buffer; if an error occurs and 'warn' is set the routine returns NULL, else 283 * it will call png_error (via png_malloc) on failure. (warn == 2 means 284 * 'silent'). 285 */ 286 static png_bytep 287 png_read_buffer(png_structrp png_ptr, png_alloc_size_t new_size, int warn) 288 { 289 png_bytep buffer = png_ptr->read_buffer; 290 291 if (buffer != NULL && new_size > png_ptr->read_buffer_size) 292 { 293 png_ptr->read_buffer = NULL; 294 png_ptr->read_buffer = NULL; 295 png_ptr->read_buffer_size = 0; 296 png_free(png_ptr, buffer); 297 buffer = NULL; 298 } 299 300 if (buffer == NULL) 301 { 302 buffer = png_voidcast(png_bytep, png_malloc_base(png_ptr, new_size)); 303 304 if (buffer != NULL) 305 { 306 png_ptr->read_buffer = buffer; 307 png_ptr->read_buffer_size = new_size; 308 } 309 310 else if (warn < 2) /* else silent */ 311 { 312 #ifdef PNG_WARNINGS_SUPPORTED 313 if (warn) 314 png_chunk_warning(png_ptr, "insufficient memory to read chunk"); 315 else 316 #endif 317 { 318 #ifdef PNG_ERROR_TEXT_SUPPORTED 319 png_chunk_error(png_ptr, "insufficient memory to read chunk"); 320 #endif 321 } 322 } 323 } 324 325 return buffer; 326 } 327 328 /* png_inflate_claim: claim the zstream for some nefarious purpose that involves 329 * decompression. Returns Z_OK on success, else a zlib error code. It checks 330 * the owner but, in final release builds, just issues a warning if some other 331 * chunk apparently owns the stream. Prior to release it does a png_error. 332 */ 333 static int 334 png_inflate_claim(png_structrp png_ptr, png_uint_32 owner) 335 { 336 if (png_ptr->zowner != 0) 337 { 338 char msg[64]; 339 340 PNG_STRING_FROM_CHUNK(msg, png_ptr->zowner); 341 /* So the message that results is "<chunk> using zstream"; this is an 342 * internal error, but is very useful for debugging. i18n requirements 343 * are minimal. 344 */ 345 (void)png_safecat(msg, (sizeof msg), 4, " using zstream"); 346 # if PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC 347 png_chunk_warning(png_ptr, msg); 348 png_ptr->zowner = 0; 349 # else 350 png_chunk_error(png_ptr, msg); 351 # endif 352 } 353 354 /* Implementation note: unlike 'png_deflate_claim' this internal function 355 * does not take the size of the data as an argument. Some efficiency could 356 * be gained by using this when it is known *if* the zlib stream itself does 357 * not record the number; however, this is an illusion: the original writer 358 * of the PNG may have selected a lower window size, and we really must 359 * follow that because, for systems with with limited capabilities, we 360 * would otherwise reject the application's attempts to use a smaller window 361 * size (zlib doesn't have an interface to say "this or lower"!). 362 * 363 * inflateReset2 was added to zlib 1.2.4; before this the window could not be 364 * reset, therefore it is necessary to always allocate the maximum window 365 * size with earlier zlibs just in case later compressed chunks need it. 366 */ 367 { 368 int ret; /* zlib return code */ 369 # if PNG_ZLIB_VERNUM >= 0x1240 370 371 # if defined(PNG_SET_OPTION_SUPPORTED) && \ 372 defined(PNG_MAXIMUM_INFLATE_WINDOW) 373 int window_bits; 374 375 if (((png_ptr->options >> PNG_MAXIMUM_INFLATE_WINDOW) & 3) == 376 PNG_OPTION_ON) 377 window_bits = 15; 378 379 else 380 window_bits = 0; 381 # else 382 # define window_bits 0 383 # endif 384 # endif 385 386 /* Set this for safety, just in case the previous owner left pointers to 387 * memory allocations. 388 */ 389 png_ptr->zstream.next_in = NULL; 390 png_ptr->zstream.avail_in = 0; 391 png_ptr->zstream.next_out = NULL; 392 png_ptr->zstream.avail_out = 0; 393 394 if (png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) 395 { 396 # if PNG_ZLIB_VERNUM < 0x1240 397 ret = inflateReset(&png_ptr->zstream); 398 # else 399 ret = inflateReset2(&png_ptr->zstream, window_bits); 400 # endif 401 } 402 403 else 404 { 405 # if PNG_ZLIB_VERNUM < 0x1240 406 ret = inflateInit(&png_ptr->zstream); 407 # else 408 ret = inflateInit2(&png_ptr->zstream, window_bits); 409 # endif 410 411 if (ret == Z_OK) 412 png_ptr->flags |= PNG_FLAG_ZSTREAM_INITIALIZED; 413 } 414 415 if (ret == Z_OK) 416 png_ptr->zowner = owner; 417 418 else 419 png_zstream_error(png_ptr, ret); 420 421 return ret; 422 } 423 424 # ifdef window_bits 425 # undef window_bits 426 # endif 427 } 428 429 #ifdef PNG_READ_COMPRESSED_TEXT_SUPPORTED 430 /* png_inflate now returns zlib error codes including Z_OK and Z_STREAM_END to 431 * allow the caller to do multiple calls if required. If the 'finish' flag is 432 * set Z_FINISH will be passed to the final inflate() call and Z_STREAM_END must 433 * be returned or there has been a problem, otherwise Z_SYNC_FLUSH is used and 434 * Z_OK or Z_STREAM_END will be returned on success. 435 * 436 * The input and output sizes are updated to the actual amounts of data consumed 437 * or written, not the amount available (as in a z_stream). The data pointers 438 * are not changed, so the next input is (data+input_size) and the next 439 * available output is (output+output_size). 440 */ 441 static int 442 png_inflate(png_structrp png_ptr, png_uint_32 owner, int finish, 443 /* INPUT: */ png_const_bytep input, png_uint_32p input_size_ptr, 444 /* OUTPUT: */ png_bytep output, png_alloc_size_t *output_size_ptr) 445 { 446 if (png_ptr->zowner == owner) /* Else not claimed */ 447 { 448 int ret; 449 png_alloc_size_t avail_out = *output_size_ptr; 450 png_uint_32 avail_in = *input_size_ptr; 451 452 /* zlib can't necessarily handle more than 65535 bytes at once (i.e. it 453 * can't even necessarily handle 65536 bytes) because the type uInt is 454 * "16 bits or more". Consequently it is necessary to chunk the input to 455 * zlib. This code uses ZLIB_IO_MAX, from pngpriv.h, as the maximum (the 456 * maximum value that can be stored in a uInt.) It is possible to set 457 * ZLIB_IO_MAX to a lower value in pngpriv.h and this may sometimes have 458 * a performance advantage, because it reduces the amount of data accessed 459 * at each step and that may give the OS more time to page it in. 460 */ 461 png_ptr->zstream.next_in = PNGZ_INPUT_CAST(input); 462 /* avail_in and avail_out are set below from 'size' */ 463 png_ptr->zstream.avail_in = 0; 464 png_ptr->zstream.avail_out = 0; 465 466 /* Read directly into the output if it is available (this is set to 467 * a local buffer below if output is NULL). 468 */ 469 if (output != NULL) 470 png_ptr->zstream.next_out = output; 471 472 do 473 { 474 uInt avail; 475 Byte local_buffer[PNG_INFLATE_BUF_SIZE]; 476 477 /* zlib INPUT BUFFER */ 478 /* The setting of 'avail_in' used to be outside the loop; by setting it 479 * inside it is possible to chunk the input to zlib and simply rely on 480 * zlib to advance the 'next_in' pointer. This allows arbitrary 481 * amounts of data to be passed through zlib at the unavoidable cost of 482 * requiring a window save (memcpy of up to 32768 output bytes) 483 * every ZLIB_IO_MAX input bytes. 484 */ 485 avail_in += png_ptr->zstream.avail_in; /* not consumed last time */ 486 487 avail = ZLIB_IO_MAX; 488 489 if (avail_in < avail) 490 avail = (uInt)avail_in; /* safe: < than ZLIB_IO_MAX */ 491 492 avail_in -= avail; 493 png_ptr->zstream.avail_in = avail; 494 495 /* zlib OUTPUT BUFFER */ 496 avail_out += png_ptr->zstream.avail_out; /* not written last time */ 497 498 avail = ZLIB_IO_MAX; /* maximum zlib can process */ 499 500 if (output == NULL) 501 { 502 /* Reset the output buffer each time round if output is NULL and 503 * make available the full buffer, up to 'remaining_space' 504 */ 505 png_ptr->zstream.next_out = local_buffer; 506 if ((sizeof local_buffer) < avail) 507 avail = (sizeof local_buffer); 508 } 509 510 if (avail_out < avail) 511 avail = (uInt)avail_out; /* safe: < ZLIB_IO_MAX */ 512 513 png_ptr->zstream.avail_out = avail; 514 avail_out -= avail; 515 516 /* zlib inflate call */ 517 /* In fact 'avail_out' may be 0 at this point, that happens at the end 518 * of the read when the final LZ end code was not passed at the end of 519 * the previous chunk of input data. Tell zlib if we have reached the 520 * end of the output buffer. 521 */ 522 ret = inflate(&png_ptr->zstream, avail_out > 0 ? Z_NO_FLUSH : 523 (finish ? Z_FINISH : Z_SYNC_FLUSH)); 524 } while (ret == Z_OK); 525 526 /* For safety kill the local buffer pointer now */ 527 if (output == NULL) 528 png_ptr->zstream.next_out = NULL; 529 530 /* Claw back the 'size' and 'remaining_space' byte counts. */ 531 avail_in += png_ptr->zstream.avail_in; 532 avail_out += png_ptr->zstream.avail_out; 533 534 /* Update the input and output sizes; the updated values are the amount 535 * consumed or written, effectively the inverse of what zlib uses. 536 */ 537 if (avail_out > 0) 538 *output_size_ptr -= avail_out; 539 540 if (avail_in > 0) 541 *input_size_ptr -= avail_in; 542 543 /* Ensure png_ptr->zstream.msg is set (even in the success case!) */ 544 png_zstream_error(png_ptr, ret); 545 return ret; 546 } 547 548 else 549 { 550 /* This is a bad internal error. The recovery assigns to the zstream msg 551 * pointer, which is not owned by the caller, but this is safe; it's only 552 * used on errors! 553 */ 554 png_ptr->zstream.msg = PNGZ_MSG_CAST("zstream unclaimed"); 555 return Z_STREAM_ERROR; 556 } 557 } 558 559 /* 560 * Decompress trailing data in a chunk. The assumption is that read_buffer 561 * points at an allocated area holding the contents of a chunk with a 562 * trailing compressed part. What we get back is an allocated area 563 * holding the original prefix part and an uncompressed version of the 564 * trailing part (the malloc area passed in is freed). 565 */ 566 static int 567 png_decompress_chunk(png_structrp png_ptr, 568 png_uint_32 chunklength, png_uint_32 prefix_size, 569 png_alloc_size_t *newlength /* must be initialized to the maximum! */, 570 int terminate /*add a '\0' to the end of the uncompressed data*/) 571 { 572 /* TODO: implement different limits for different types of chunk. 573 * 574 * The caller supplies *newlength set to the maximum length of the 575 * uncompressed data, but this routine allocates space for the prefix and 576 * maybe a '\0' terminator too. We have to assume that 'prefix_size' is 577 * limited only by the maximum chunk size. 578 */ 579 png_alloc_size_t limit = PNG_SIZE_MAX; 580 581 # ifdef PNG_SET_CHUNK_MALLOC_LIMIT_SUPPORTED 582 if (png_ptr->user_chunk_malloc_max > 0 && 583 png_ptr->user_chunk_malloc_max < limit) 584 limit = png_ptr->user_chunk_malloc_max; 585 # elif PNG_USER_CHUNK_MALLOC_MAX > 0 586 if (PNG_USER_CHUNK_MALLOC_MAX < limit) 587 limit = PNG_USER_CHUNK_MALLOC_MAX; 588 # endif 589 590 if (limit >= prefix_size + (terminate != 0)) 591 { 592 int ret; 593 594 limit -= prefix_size + (terminate != 0); 595 596 if (limit < *newlength) 597 *newlength = limit; 598 599 /* Now try to claim the stream. */ 600 ret = png_inflate_claim(png_ptr, png_ptr->chunk_name); 601 602 if (ret == Z_OK) 603 { 604 png_uint_32 lzsize = chunklength - prefix_size; 605 606 ret = png_inflate(png_ptr, png_ptr->chunk_name, 1/*finish*/, 607 /* input: */ png_ptr->read_buffer + prefix_size, &lzsize, 608 /* output: */ NULL, newlength); 609 610 if (ret == Z_STREAM_END) 611 { 612 /* Use 'inflateReset' here, not 'inflateReset2' because this 613 * preserves the previously decided window size (otherwise it would 614 * be necessary to store the previous window size.) In practice 615 * this doesn't matter anyway, because png_inflate will call inflate 616 * with Z_FINISH in almost all cases, so the window will not be 617 * maintained. 618 */ 619 if (inflateReset(&png_ptr->zstream) == Z_OK) 620 { 621 /* Because of the limit checks above we know that the new, 622 * expanded, size will fit in a size_t (let alone an 623 * png_alloc_size_t). Use png_malloc_base here to avoid an 624 * extra OOM message. 625 */ 626 png_alloc_size_t new_size = *newlength; 627 png_alloc_size_t buffer_size = prefix_size + new_size + 628 (terminate != 0); 629 png_bytep text = png_voidcast(png_bytep, png_malloc_base(png_ptr, 630 buffer_size)); 631 632 if (text != NULL) 633 { 634 ret = png_inflate(png_ptr, png_ptr->chunk_name, 1/*finish*/, 635 png_ptr->read_buffer + prefix_size, &lzsize, 636 text + prefix_size, newlength); 637 638 if (ret == Z_STREAM_END) 639 { 640 if (new_size == *newlength) 641 { 642 if (terminate) 643 text[prefix_size + *newlength] = 0; 644 645 if (prefix_size > 0) 646 memcpy(text, png_ptr->read_buffer, prefix_size); 647 648 { 649 png_bytep old_ptr = png_ptr->read_buffer; 650 651 png_ptr->read_buffer = text; 652 png_ptr->read_buffer_size = buffer_size; 653 text = old_ptr; /* freed below */ 654 } 655 } 656 657 else 658 { 659 /* The size changed on the second read, there can be no 660 * guarantee that anything is correct at this point. 661 * The 'msg' pointer has been set to "unexpected end of 662 * LZ stream", which is fine, but return an error code 663 * that the caller won't accept. 664 */ 665 ret = PNG_UNEXPECTED_ZLIB_RETURN; 666 } 667 } 668 669 else if (ret == Z_OK) 670 ret = PNG_UNEXPECTED_ZLIB_RETURN; /* for safety */ 671 672 /* Free the text pointer (this is the old read_buffer on 673 * success) 674 */ 675 png_free(png_ptr, text); 676 677 /* This really is very benign, but it's still an error because 678 * the extra space may otherwise be used as a Trojan Horse. 679 */ 680 if (ret == Z_STREAM_END && 681 chunklength - prefix_size != lzsize) 682 png_chunk_benign_error(png_ptr, "extra compressed data"); 683 } 684 685 else 686 { 687 /* Out of memory allocating the buffer */ 688 ret = Z_MEM_ERROR; 689 png_zstream_error(png_ptr, Z_MEM_ERROR); 690 } 691 } 692 693 else 694 { 695 /* inflateReset failed, store the error message */ 696 png_zstream_error(png_ptr, ret); 697 698 if (ret == Z_STREAM_END) 699 ret = PNG_UNEXPECTED_ZLIB_RETURN; 700 } 701 } 702 703 else if (ret == Z_OK) 704 ret = PNG_UNEXPECTED_ZLIB_RETURN; 705 706 /* Release the claimed stream */ 707 png_ptr->zowner = 0; 708 } 709 710 else /* the claim failed */ if (ret == Z_STREAM_END) /* impossible! */ 711 ret = PNG_UNEXPECTED_ZLIB_RETURN; 712 713 return ret; 714 } 715 716 else 717 { 718 /* Application/configuration limits exceeded */ 719 png_zstream_error(png_ptr, Z_MEM_ERROR); 720 return Z_MEM_ERROR; 721 } 722 } 723 #endif /* PNG_READ_COMPRESSED_TEXT_SUPPORTED */ 724 725 #ifdef PNG_READ_iCCP_SUPPORTED 726 /* Perform a partial read and decompress, producing 'avail_out' bytes and 727 * reading from the current chunk as required. 728 */ 729 static int 730 png_inflate_read(png_structrp png_ptr, png_bytep read_buffer, uInt read_size, 731 png_uint_32p chunk_bytes, png_bytep next_out, png_alloc_size_t *out_size, 732 int finish) 733 { 734 if (png_ptr->zowner == png_ptr->chunk_name) 735 { 736 int ret; 737 738 /* next_in and avail_in must have been initialized by the caller. */ 739 png_ptr->zstream.next_out = next_out; 740 png_ptr->zstream.avail_out = 0; /* set in the loop */ 741 742 do 743 { 744 if (png_ptr->zstream.avail_in == 0) 745 { 746 if (read_size > *chunk_bytes) 747 read_size = (uInt)*chunk_bytes; 748 *chunk_bytes -= read_size; 749 750 if (read_size > 0) 751 png_crc_read(png_ptr, read_buffer, read_size); 752 753 png_ptr->zstream.next_in = read_buffer; 754 png_ptr->zstream.avail_in = read_size; 755 } 756 757 if (png_ptr->zstream.avail_out == 0) 758 { 759 uInt avail = ZLIB_IO_MAX; 760 if (avail > *out_size) 761 avail = (uInt)*out_size; 762 *out_size -= avail; 763 764 png_ptr->zstream.avail_out = avail; 765 } 766 767 /* Use Z_SYNC_FLUSH when there is no more chunk data to ensure that all 768 * the available output is produced; this allows reading of truncated 769 * streams. 770 */ 771 ret = inflate(&png_ptr->zstream, 772 *chunk_bytes > 0 ? Z_NO_FLUSH : (finish ? Z_FINISH : Z_SYNC_FLUSH)); 773 } 774 while (ret == Z_OK && (*out_size > 0 || png_ptr->zstream.avail_out > 0)); 775 776 *out_size += png_ptr->zstream.avail_out; 777 png_ptr->zstream.avail_out = 0; /* Should not be required, but is safe */ 778 779 /* Ensure the error message pointer is always set: */ 780 png_zstream_error(png_ptr, ret); 781 return ret; 782 } 783 784 else 785 { 786 png_ptr->zstream.msg = PNGZ_MSG_CAST("zstream unclaimed"); 787 return Z_STREAM_ERROR; 788 } 789 } 790 #endif 791 792 /* Read and check the IDHR chunk */ 793 void /* PRIVATE */ 794 png_handle_IHDR(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 795 { 796 png_byte buf[13]; 797 png_uint_32 width, height; 798 int bit_depth, color_type, compression_type, filter_type; 799 int interlace_type; 800 801 png_debug(1, "in png_handle_IHDR"); 802 803 if (png_ptr->mode & PNG_HAVE_IHDR) 804 png_chunk_error(png_ptr, "out of place"); 805 806 /* Check the length */ 807 if (length != 13) 808 png_chunk_error(png_ptr, "invalid"); 809 810 png_ptr->mode |= PNG_HAVE_IHDR; 811 812 png_crc_read(png_ptr, buf, 13); 813 png_crc_finish(png_ptr, 0); 814 815 width = png_get_uint_31(png_ptr, buf); 816 height = png_get_uint_31(png_ptr, buf + 4); 817 bit_depth = buf[8]; 818 color_type = buf[9]; 819 compression_type = buf[10]; 820 filter_type = buf[11]; 821 interlace_type = buf[12]; 822 823 /* Set internal variables */ 824 png_ptr->width = width; 825 png_ptr->height = height; 826 png_ptr->bit_depth = (png_byte)bit_depth; 827 png_ptr->interlaced = (png_byte)interlace_type; 828 png_ptr->color_type = (png_byte)color_type; 829 #ifdef PNG_MNG_FEATURES_SUPPORTED 830 png_ptr->filter_type = (png_byte)filter_type; 831 #endif 832 png_ptr->compression_type = (png_byte)compression_type; 833 834 /* Find number of channels */ 835 switch (png_ptr->color_type) 836 { 837 default: /* invalid, png_set_IHDR calls png_error */ 838 case PNG_COLOR_TYPE_GRAY: 839 case PNG_COLOR_TYPE_PALETTE: 840 png_ptr->channels = 1; 841 break; 842 843 case PNG_COLOR_TYPE_RGB: 844 png_ptr->channels = 3; 845 break; 846 847 case PNG_COLOR_TYPE_GRAY_ALPHA: 848 png_ptr->channels = 2; 849 break; 850 851 case PNG_COLOR_TYPE_RGB_ALPHA: 852 png_ptr->channels = 4; 853 break; 854 } 855 856 /* Set up other useful info */ 857 png_ptr->pixel_depth = (png_byte)(png_ptr->bit_depth * 858 png_ptr->channels); 859 png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->width); 860 png_debug1(3, "bit_depth = %d", png_ptr->bit_depth); 861 png_debug1(3, "channels = %d", png_ptr->channels); 862 png_debug1(3, "rowbytes = %lu", (unsigned long)png_ptr->rowbytes); 863 png_set_IHDR(png_ptr, info_ptr, width, height, bit_depth, 864 color_type, interlace_type, compression_type, filter_type); 865 } 866 867 /* Read and check the palette */ 868 void /* PRIVATE */ 869 png_handle_PLTE(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 870 { 871 png_color palette[PNG_MAX_PALETTE_LENGTH]; 872 int num, i; 873 #ifdef PNG_POINTER_INDEXING_SUPPORTED 874 png_colorp pal_ptr; 875 #endif 876 877 png_debug(1, "in png_handle_PLTE"); 878 879 if (!(png_ptr->mode & PNG_HAVE_IHDR)) 880 png_chunk_error(png_ptr, "missing IHDR"); 881 882 /* Moved to before the 'after IDAT' check below because otherwise duplicate 883 * PLTE chunks are potentially ignored (the spec says there shall not be more 884 * than one PLTE, the error is not treated as benign, so this check trumps 885 * the requirement that PLTE appears before IDAT.) 886 */ 887 else if (png_ptr->mode & PNG_HAVE_PLTE) 888 png_chunk_error(png_ptr, "duplicate"); 889 890 else if (png_ptr->mode & PNG_HAVE_IDAT) 891 { 892 /* This is benign because the non-benign error happened before, when an 893 * IDAT was encountered in a color-mapped image with no PLTE. 894 */ 895 png_crc_finish(png_ptr, length); 896 png_chunk_benign_error(png_ptr, "out of place"); 897 return; 898 } 899 900 png_ptr->mode |= PNG_HAVE_PLTE; 901 902 if (!(png_ptr->color_type & PNG_COLOR_MASK_COLOR)) 903 { 904 png_crc_finish(png_ptr, length); 905 png_chunk_benign_error(png_ptr, "ignored in grayscale PNG"); 906 return; 907 } 908 909 #ifndef PNG_READ_OPT_PLTE_SUPPORTED 910 if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE) 911 { 912 png_crc_finish(png_ptr, length); 913 return; 914 } 915 #endif 916 917 if (length > 3*PNG_MAX_PALETTE_LENGTH || length % 3) 918 { 919 png_crc_finish(png_ptr, length); 920 921 if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE) 922 png_chunk_benign_error(png_ptr, "invalid"); 923 924 else 925 png_chunk_error(png_ptr, "invalid"); 926 927 return; 928 } 929 930 /* The cast is safe because 'length' is less than 3*PNG_MAX_PALETTE_LENGTH */ 931 num = (int)length / 3; 932 933 #ifdef PNG_POINTER_INDEXING_SUPPORTED 934 for (i = 0, pal_ptr = palette; i < num; i++, pal_ptr++) 935 { 936 png_byte buf[3]; 937 938 png_crc_read(png_ptr, buf, 3); 939 pal_ptr->red = buf[0]; 940 pal_ptr->green = buf[1]; 941 pal_ptr->blue = buf[2]; 942 } 943 #else 944 for (i = 0; i < num; i++) 945 { 946 png_byte buf[3]; 947 948 png_crc_read(png_ptr, buf, 3); 949 /* Don't depend upon png_color being any order */ 950 palette[i].red = buf[0]; 951 palette[i].green = buf[1]; 952 palette[i].blue = buf[2]; 953 } 954 #endif 955 956 /* If we actually need the PLTE chunk (ie for a paletted image), we do 957 * whatever the normal CRC configuration tells us. However, if we 958 * have an RGB image, the PLTE can be considered ancillary, so 959 * we will act as though it is. 960 */ 961 #ifndef PNG_READ_OPT_PLTE_SUPPORTED 962 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) 963 #endif 964 { 965 png_crc_finish(png_ptr, 0); 966 } 967 968 #ifndef PNG_READ_OPT_PLTE_SUPPORTED 969 else if (png_crc_error(png_ptr)) /* Only if we have a CRC error */ 970 { 971 /* If we don't want to use the data from an ancillary chunk, 972 * we have two options: an error abort, or a warning and we 973 * ignore the data in this chunk (which should be OK, since 974 * it's considered ancillary for a RGB or RGBA image). 975 * 976 * IMPLEMENTATION NOTE: this is only here because png_crc_finish uses the 977 * chunk type to determine whether to check the ancillary or the critical 978 * flags. 979 */ 980 if (!(png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_USE)) 981 { 982 if (png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) 983 { 984 png_chunk_benign_error(png_ptr, "CRC error"); 985 } 986 987 else 988 { 989 png_chunk_warning(png_ptr, "CRC error"); 990 return; 991 } 992 } 993 994 /* Otherwise, we (optionally) emit a warning and use the chunk. */ 995 else if (!(png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN)) 996 { 997 png_chunk_warning(png_ptr, "CRC error"); 998 } 999 } 1000 #endif 1001 1002 /* TODO: png_set_PLTE has the side effect of setting png_ptr->palette to its 1003 * own copy of the palette. This has the side effect that when png_start_row 1004 * is called (this happens after any call to png_read_update_info) the 1005 * info_ptr palette gets changed. This is extremely unexpected and 1006 * confusing. 1007 * 1008 * Fix this by not sharing the palette in this way. 1009 */ 1010 png_set_PLTE(png_ptr, info_ptr, palette, num); 1011 1012 /* The three chunks, bKGD, hIST and tRNS *must* appear after PLTE and before 1013 * IDAT. Prior to 1.6.0 this was not checked; instead the code merely 1014 * checked the apparent validity of a tRNS chunk inserted before PLTE on a 1015 * palette PNG. 1.6.0 attempts to rigorously follow the standard and 1016 * therefore does a benign error if the erroneous condition is detected *and* 1017 * cancels the tRNS if the benign error returns. The alternative is to 1018 * amend the standard since it would be rather hypocritical of the standards 1019 * maintainers to ignore it. 1020 */ 1021 #ifdef PNG_READ_tRNS_SUPPORTED 1022 if (png_ptr->num_trans > 0 || 1023 (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS) != 0)) 1024 { 1025 /* Cancel this because otherwise it would be used if the transforms 1026 * require it. Don't cancel the 'valid' flag because this would prevent 1027 * detection of duplicate chunks. 1028 */ 1029 png_ptr->num_trans = 0; 1030 1031 if (info_ptr != NULL) 1032 info_ptr->num_trans = 0; 1033 1034 png_chunk_benign_error(png_ptr, "tRNS must be after"); 1035 } 1036 #endif 1037 1038 #ifdef PNG_READ_hIST_SUPPORTED 1039 if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST) != 0) 1040 png_chunk_benign_error(png_ptr, "hIST must be after"); 1041 #endif 1042 1043 #ifdef PNG_READ_bKGD_SUPPORTED 1044 if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD) != 0) 1045 png_chunk_benign_error(png_ptr, "bKGD must be after"); 1046 #endif 1047 } 1048 1049 void /* PRIVATE */ 1050 png_handle_IEND(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 1051 { 1052 png_debug(1, "in png_handle_IEND"); 1053 1054 if (!(png_ptr->mode & PNG_HAVE_IHDR) || !(png_ptr->mode & PNG_HAVE_IDAT)) 1055 png_chunk_error(png_ptr, "out of place"); 1056 1057 png_ptr->mode |= (PNG_AFTER_IDAT | PNG_HAVE_IEND); 1058 1059 png_crc_finish(png_ptr, length); 1060 1061 if (length != 0) 1062 png_chunk_benign_error(png_ptr, "invalid"); 1063 1064 PNG_UNUSED(info_ptr) 1065 } 1066 1067 #ifdef PNG_READ_gAMA_SUPPORTED 1068 void /* PRIVATE */ 1069 png_handle_gAMA(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 1070 { 1071 png_fixed_point igamma; 1072 png_byte buf[4]; 1073 1074 png_debug(1, "in png_handle_gAMA"); 1075 1076 if (!(png_ptr->mode & PNG_HAVE_IHDR)) 1077 png_chunk_error(png_ptr, "missing IHDR"); 1078 1079 else if (png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) 1080 { 1081 png_crc_finish(png_ptr, length); 1082 png_chunk_benign_error(png_ptr, "out of place"); 1083 return; 1084 } 1085 1086 if (length != 4) 1087 { 1088 png_crc_finish(png_ptr, length); 1089 png_chunk_benign_error(png_ptr, "invalid"); 1090 return; 1091 } 1092 1093 png_crc_read(png_ptr, buf, 4); 1094 1095 if (png_crc_finish(png_ptr, 0)) 1096 return; 1097 1098 igamma = png_get_fixed_point(NULL, buf); 1099 1100 png_colorspace_set_gamma(png_ptr, &png_ptr->colorspace, igamma); 1101 png_colorspace_sync(png_ptr, info_ptr); 1102 } 1103 #endif 1104 1105 #ifdef PNG_READ_sBIT_SUPPORTED 1106 void /* PRIVATE */ 1107 png_handle_sBIT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 1108 { 1109 unsigned int truelen; 1110 png_byte buf[4]; 1111 1112 png_debug(1, "in png_handle_sBIT"); 1113 1114 buf[0] = buf[1] = buf[2] = buf[3] = 0; 1115 1116 if (!(png_ptr->mode & PNG_HAVE_IHDR)) 1117 png_chunk_error(png_ptr, "missing IHDR"); 1118 1119 else if (png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) 1120 { 1121 png_crc_finish(png_ptr, length); 1122 png_chunk_benign_error(png_ptr, "out of place"); 1123 return; 1124 } 1125 1126 if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sBIT)) 1127 { 1128 png_crc_finish(png_ptr, length); 1129 png_chunk_benign_error(png_ptr, "duplicate"); 1130 return; 1131 } 1132 1133 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) 1134 truelen = 3; 1135 1136 else 1137 truelen = png_ptr->channels; 1138 1139 if (length != truelen || length > 4) 1140 { 1141 png_chunk_benign_error(png_ptr, "invalid"); 1142 png_crc_finish(png_ptr, length); 1143 return; 1144 } 1145 1146 png_crc_read(png_ptr, buf, truelen); 1147 1148 if (png_crc_finish(png_ptr, 0)) 1149 return; 1150 1151 if (png_ptr->color_type & PNG_COLOR_MASK_COLOR) 1152 { 1153 png_ptr->sig_bit.red = buf[0]; 1154 png_ptr->sig_bit.green = buf[1]; 1155 png_ptr->sig_bit.blue = buf[2]; 1156 png_ptr->sig_bit.alpha = buf[3]; 1157 } 1158 1159 else 1160 { 1161 png_ptr->sig_bit.gray = buf[0]; 1162 png_ptr->sig_bit.red = buf[0]; 1163 png_ptr->sig_bit.green = buf[0]; 1164 png_ptr->sig_bit.blue = buf[0]; 1165 png_ptr->sig_bit.alpha = buf[1]; 1166 } 1167 1168 png_set_sBIT(png_ptr, info_ptr, &(png_ptr->sig_bit)); 1169 } 1170 #endif 1171 1172 #ifdef PNG_READ_cHRM_SUPPORTED 1173 void /* PRIVATE */ 1174 png_handle_cHRM(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 1175 { 1176 png_byte buf[32]; 1177 png_xy xy; 1178 1179 png_debug(1, "in png_handle_cHRM"); 1180 1181 if (!(png_ptr->mode & PNG_HAVE_IHDR)) 1182 png_chunk_error(png_ptr, "missing IHDR"); 1183 1184 else if (png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) 1185 { 1186 png_crc_finish(png_ptr, length); 1187 png_chunk_benign_error(png_ptr, "out of place"); 1188 return; 1189 } 1190 1191 if (length != 32) 1192 { 1193 png_crc_finish(png_ptr, length); 1194 png_chunk_benign_error(png_ptr, "invalid"); 1195 return; 1196 } 1197 1198 png_crc_read(png_ptr, buf, 32); 1199 1200 if (png_crc_finish(png_ptr, 0)) 1201 return; 1202 1203 xy.whitex = png_get_fixed_point(NULL, buf); 1204 xy.whitey = png_get_fixed_point(NULL, buf + 4); 1205 xy.redx = png_get_fixed_point(NULL, buf + 8); 1206 xy.redy = png_get_fixed_point(NULL, buf + 12); 1207 xy.greenx = png_get_fixed_point(NULL, buf + 16); 1208 xy.greeny = png_get_fixed_point(NULL, buf + 20); 1209 xy.bluex = png_get_fixed_point(NULL, buf + 24); 1210 xy.bluey = png_get_fixed_point(NULL, buf + 28); 1211 1212 if (xy.whitex == PNG_FIXED_ERROR || 1213 xy.whitey == PNG_FIXED_ERROR || 1214 xy.redx == PNG_FIXED_ERROR || 1215 xy.redy == PNG_FIXED_ERROR || 1216 xy.greenx == PNG_FIXED_ERROR || 1217 xy.greeny == PNG_FIXED_ERROR || 1218 xy.bluex == PNG_FIXED_ERROR || 1219 xy.bluey == PNG_FIXED_ERROR) 1220 { 1221 png_chunk_benign_error(png_ptr, "invalid values"); 1222 return; 1223 } 1224 1225 /* If a colorspace error has already been output skip this chunk */ 1226 if (png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) 1227 return; 1228 1229 if (png_ptr->colorspace.flags & PNG_COLORSPACE_FROM_cHRM) 1230 { 1231 png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID; 1232 png_colorspace_sync(png_ptr, info_ptr); 1233 png_chunk_benign_error(png_ptr, "duplicate"); 1234 return; 1235 } 1236 1237 png_ptr->colorspace.flags |= PNG_COLORSPACE_FROM_cHRM; 1238 (void)png_colorspace_set_chromaticities(png_ptr, &png_ptr->colorspace, &xy, 1239 1/*prefer cHRM values*/); 1240 png_colorspace_sync(png_ptr, info_ptr); 1241 } 1242 #endif 1243 1244 #ifdef PNG_READ_sRGB_SUPPORTED 1245 void /* PRIVATE */ 1246 png_handle_sRGB(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 1247 { 1248 png_byte intent; 1249 1250 png_debug(1, "in png_handle_sRGB"); 1251 1252 if (!(png_ptr->mode & PNG_HAVE_IHDR)) 1253 png_chunk_error(png_ptr, "missing IHDR"); 1254 1255 else if (png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) 1256 { 1257 png_crc_finish(png_ptr, length); 1258 png_chunk_benign_error(png_ptr, "out of place"); 1259 return; 1260 } 1261 1262 if (length != 1) 1263 { 1264 png_crc_finish(png_ptr, length); 1265 png_chunk_benign_error(png_ptr, "invalid"); 1266 return; 1267 } 1268 1269 png_crc_read(png_ptr, &intent, 1); 1270 1271 if (png_crc_finish(png_ptr, 0)) 1272 return; 1273 1274 /* If a colorspace error has already been output skip this chunk */ 1275 if (png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) 1276 return; 1277 1278 /* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect 1279 * this. 1280 */ 1281 if (png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_INTENT) 1282 { 1283 png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID; 1284 png_colorspace_sync(png_ptr, info_ptr); 1285 png_chunk_benign_error(png_ptr, "too many profiles"); 1286 return; 1287 } 1288 1289 (void)png_colorspace_set_sRGB(png_ptr, &png_ptr->colorspace, intent); 1290 png_colorspace_sync(png_ptr, info_ptr); 1291 } 1292 #endif /* PNG_READ_sRGB_SUPPORTED */ 1293 1294 #ifdef PNG_READ_iCCP_SUPPORTED 1295 void /* PRIVATE */ 1296 png_handle_iCCP(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 1297 /* Note: this does not properly handle profiles that are > 64K under DOS */ 1298 { 1299 png_const_charp errmsg = NULL; /* error message output, or no error */ 1300 int finished = 0; /* crc checked */ 1301 1302 png_debug(1, "in png_handle_iCCP"); 1303 1304 if (!(png_ptr->mode & PNG_HAVE_IHDR)) 1305 png_chunk_error(png_ptr, "missing IHDR"); 1306 1307 else if (png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) 1308 { 1309 png_crc_finish(png_ptr, length); 1310 png_chunk_benign_error(png_ptr, "out of place"); 1311 return; 1312 } 1313 1314 /* Consistent with all the above colorspace handling an obviously *invalid* 1315 * chunk is just ignored, so does not invalidate the color space. An 1316 * alternative is to set the 'invalid' flags at the start of this routine 1317 * and only clear them in they were not set before and all the tests pass. 1318 * The minimum 'deflate' stream is assumed to be just the 2 byte header and 4 1319 * byte checksum. The keyword must be one character and there is a 1320 * terminator (0) byte and the compression method. 1321 */ 1322 if (length < 9) 1323 { 1324 png_crc_finish(png_ptr, length); 1325 png_chunk_benign_error(png_ptr, "too short"); 1326 return; 1327 } 1328 1329 /* If a colorspace error has already been output skip this chunk */ 1330 if (png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) 1331 { 1332 png_crc_finish(png_ptr, length); 1333 return; 1334 } 1335 1336 /* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect 1337 * this. 1338 */ 1339 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_INTENT) == 0) 1340 { 1341 uInt read_length, keyword_length; 1342 char keyword[81]; 1343 1344 /* Find the keyword; the keyword plus separator and compression method 1345 * bytes can be at most 81 characters long. 1346 */ 1347 read_length = 81; /* maximum */ 1348 if (read_length > length) 1349 read_length = (uInt)length; 1350 1351 png_crc_read(png_ptr, (png_bytep)keyword, read_length); 1352 length -= read_length; 1353 1354 keyword_length = 0; 1355 while (keyword_length < 80 && keyword_length < read_length && 1356 keyword[keyword_length] != 0) 1357 ++keyword_length; 1358 1359 /* TODO: make the keyword checking common */ 1360 if (keyword_length >= 1 && keyword_length <= 79) 1361 { 1362 /* We only understand '0' compression - deflate - so if we get a 1363 * different value we can't safely decode the chunk. 1364 */ 1365 if (keyword_length+1 < read_length && 1366 keyword[keyword_length+1] == PNG_COMPRESSION_TYPE_BASE) 1367 { 1368 read_length -= keyword_length+2; 1369 1370 if (png_inflate_claim(png_ptr, png_iCCP) == Z_OK) 1371 { 1372 Byte profile_header[132]; 1373 Byte local_buffer[PNG_INFLATE_BUF_SIZE]; 1374 png_alloc_size_t size = (sizeof profile_header); 1375 1376 png_ptr->zstream.next_in = (Bytef*)keyword + (keyword_length+2); 1377 png_ptr->zstream.avail_in = read_length; 1378 (void)png_inflate_read(png_ptr, local_buffer, 1379 (sizeof local_buffer), &length, profile_header, &size, 1380 0/*finish: don't, because the output is too small*/); 1381 1382 if (size == 0) 1383 { 1384 /* We have the ICC profile header; do the basic header checks. 1385 */ 1386 const png_uint_32 profile_length = 1387 png_get_uint_32(profile_header); 1388 1389 if (png_icc_check_length(png_ptr, &png_ptr->colorspace, 1390 keyword, profile_length)) 1391 { 1392 /* The length is apparently ok, so we can check the 132 1393 * byte header. 1394 */ 1395 if (png_icc_check_header(png_ptr, &png_ptr->colorspace, 1396 keyword, profile_length, profile_header, 1397 png_ptr->color_type)) 1398 { 1399 /* Now read the tag table; a variable size buffer is 1400 * needed at this point, allocate one for the whole 1401 * profile. The header check has already validated 1402 * that none of these stuff will overflow. 1403 */ 1404 const png_uint_32 tag_count = png_get_uint_32( 1405 profile_header+128); 1406 png_bytep profile = png_read_buffer(png_ptr, 1407 profile_length, 2/*silent*/); 1408 1409 if (profile != NULL) 1410 { 1411 memcpy(profile, profile_header, 1412 (sizeof profile_header)); 1413 1414 size = 12 * tag_count; 1415 1416 (void)png_inflate_read(png_ptr, local_buffer, 1417 (sizeof local_buffer), &length, 1418 profile + (sizeof profile_header), &size, 0); 1419 1420 /* Still expect a a buffer error because we expect 1421 * there to be some tag data! 1422 */ 1423 if (size == 0) 1424 { 1425 if (png_icc_check_tag_table(png_ptr, 1426 &png_ptr->colorspace, keyword, profile_length, 1427 profile)) 1428 { 1429 /* The profile has been validated for basic 1430 * security issues, so read the whole thing in. 1431 */ 1432 size = profile_length - (sizeof profile_header) 1433 - 12 * tag_count; 1434 1435 (void)png_inflate_read(png_ptr, local_buffer, 1436 (sizeof local_buffer), &length, 1437 profile + (sizeof profile_header) + 1438 12 * tag_count, &size, 1/*finish*/); 1439 1440 if (length > 0 && !(png_ptr->flags & 1441 PNG_FLAG_BENIGN_ERRORS_WARN)) 1442 errmsg = "extra compressed data"; 1443 1444 /* But otherwise allow extra data: */ 1445 else if (size == 0) 1446 { 1447 if (length > 0) 1448 { 1449 /* This can be handled completely, so 1450 * keep going. 1451 */ 1452 png_chunk_warning(png_ptr, 1453 "extra compressed data"); 1454 } 1455 1456 png_crc_finish(png_ptr, length); 1457 finished = 1; 1458 1459 # ifdef PNG_sRGB_SUPPORTED 1460 /* Check for a match against sRGB */ 1461 png_icc_set_sRGB(png_ptr, 1462 &png_ptr->colorspace, profile, 1463 png_ptr->zstream.adler); 1464 # endif 1465 1466 /* Steal the profile for info_ptr. */ 1467 if (info_ptr != NULL) 1468 { 1469 png_free_data(png_ptr, info_ptr, 1470 PNG_FREE_ICCP, 0); 1471 1472 info_ptr->iccp_name = png_voidcast(char*, 1473 png_malloc_base(png_ptr, 1474 keyword_length+1)); 1475 if (info_ptr->iccp_name != NULL) 1476 { 1477 memcpy(info_ptr->iccp_name, keyword, 1478 keyword_length+1); 1479 info_ptr->iccp_proflen = 1480 profile_length; 1481 info_ptr->iccp_profile = profile; 1482 png_ptr->read_buffer = NULL; /*steal*/ 1483 info_ptr->free_me |= PNG_FREE_ICCP; 1484 info_ptr->valid |= PNG_INFO_iCCP; 1485 } 1486 1487 else 1488 { 1489 png_ptr->colorspace.flags |= 1490 PNG_COLORSPACE_INVALID; 1491 errmsg = "out of memory"; 1492 } 1493 } 1494 1495 /* else the profile remains in the read 1496 * buffer which gets reused for subsequent 1497 * chunks. 1498 */ 1499 1500 if (info_ptr != NULL) 1501 png_colorspace_sync(png_ptr, info_ptr); 1502 1503 if (errmsg == NULL) 1504 { 1505 png_ptr->zowner = 0; 1506 return; 1507 } 1508 } 1509 1510 else if (size > 0) 1511 errmsg = "truncated"; 1512 1513 else 1514 errmsg = png_ptr->zstream.msg; 1515 } 1516 1517 /* else png_icc_check_tag_table output an error */ 1518 } 1519 1520 else /* profile truncated */ 1521 errmsg = png_ptr->zstream.msg; 1522 } 1523 1524 else 1525 errmsg = "out of memory"; 1526 } 1527 1528 /* else png_icc_check_header output an error */ 1529 } 1530 1531 /* else png_icc_check_length output an error */ 1532 } 1533 1534 else /* profile truncated */ 1535 errmsg = png_ptr->zstream.msg; 1536 1537 /* Release the stream */ 1538 png_ptr->zowner = 0; 1539 } 1540 1541 else /* png_inflate_claim failed */ 1542 errmsg = png_ptr->zstream.msg; 1543 } 1544 1545 else 1546 errmsg = "bad compression method"; /* or missing */ 1547 } 1548 1549 else 1550 errmsg = "bad keyword"; 1551 } 1552 1553 else 1554 errmsg = "too many profiles"; 1555 1556 /* Failure: the reason is in 'errmsg' */ 1557 if (!finished) 1558 png_crc_finish(png_ptr, length); 1559 1560 png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID; 1561 png_colorspace_sync(png_ptr, info_ptr); 1562 if (errmsg != NULL) /* else already output */ 1563 png_chunk_benign_error(png_ptr, errmsg); 1564 } 1565 #endif /* PNG_READ_iCCP_SUPPORTED */ 1566 1567 #ifdef PNG_READ_sPLT_SUPPORTED 1568 void /* PRIVATE */ 1569 png_handle_sPLT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 1570 /* Note: this does not properly handle chunks that are > 64K under DOS */ 1571 { 1572 png_bytep entry_start, buffer; 1573 png_sPLT_t new_palette; 1574 png_sPLT_entryp pp; 1575 png_uint_32 data_length; 1576 int entry_size, i; 1577 png_uint_32 skip = 0; 1578 png_uint_32 dl; 1579 png_size_t max_dl; 1580 1581 png_debug(1, "in png_handle_sPLT"); 1582 1583 #ifdef PNG_USER_LIMITS_SUPPORTED 1584 if (png_ptr->user_chunk_cache_max != 0) 1585 { 1586 if (png_ptr->user_chunk_cache_max == 1) 1587 { 1588 png_crc_finish(png_ptr, length); 1589 return; 1590 } 1591 1592 if (--png_ptr->user_chunk_cache_max == 1) 1593 { 1594 png_warning(png_ptr, "No space in chunk cache for sPLT"); 1595 png_crc_finish(png_ptr, length); 1596 return; 1597 } 1598 } 1599 #endif 1600 1601 if (!(png_ptr->mode & PNG_HAVE_IHDR)) 1602 png_chunk_error(png_ptr, "missing IHDR"); 1603 1604 else if (png_ptr->mode & PNG_HAVE_IDAT) 1605 { 1606 png_crc_finish(png_ptr, length); 1607 png_chunk_benign_error(png_ptr, "out of place"); 1608 return; 1609 } 1610 1611 #ifdef PNG_MAX_MALLOC_64K 1612 if (length > 65535U) 1613 { 1614 png_crc_finish(png_ptr, length); 1615 png_chunk_benign_error(png_ptr, "too large to fit in memory"); 1616 return; 1617 } 1618 #endif 1619 1620 buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/); 1621 if (buffer == NULL) 1622 { 1623 png_crc_finish(png_ptr, length); 1624 png_chunk_benign_error(png_ptr, "out of memory"); 1625 return; 1626 } 1627 1628 1629 /* WARNING: this may break if size_t is less than 32 bits; it is assumed 1630 * that the PNG_MAX_MALLOC_64K test is enabled in this case, but this is a 1631 * potential breakage point if the types in pngconf.h aren't exactly right. 1632 */ 1633 png_crc_read(png_ptr, buffer, length); 1634 1635 if (png_crc_finish(png_ptr, skip)) 1636 return; 1637 1638 buffer[length] = 0; 1639 1640 for (entry_start = buffer; *entry_start; entry_start++) 1641 /* Empty loop to find end of name */ ; 1642 1643 ++entry_start; 1644 1645 /* A sample depth should follow the separator, and we should be on it */ 1646 if (entry_start > buffer + length - 2) 1647 { 1648 png_warning(png_ptr, "malformed sPLT chunk"); 1649 return; 1650 } 1651 1652 new_palette.depth = *entry_start++; 1653 entry_size = (new_palette.depth == 8 ? 6 : 10); 1654 /* This must fit in a png_uint_32 because it is derived from the original 1655 * chunk data length. 1656 */ 1657 data_length = length - (png_uint_32)(entry_start - buffer); 1658 1659 /* Integrity-check the data length */ 1660 if (data_length % entry_size) 1661 { 1662 png_warning(png_ptr, "sPLT chunk has bad length"); 1663 return; 1664 } 1665 1666 dl = (png_int_32)(data_length / entry_size); 1667 max_dl = PNG_SIZE_MAX / (sizeof (png_sPLT_entry)); 1668 1669 if (dl > max_dl) 1670 { 1671 png_warning(png_ptr, "sPLT chunk too long"); 1672 return; 1673 } 1674 1675 new_palette.nentries = (png_int_32)(data_length / entry_size); 1676 1677 new_palette.entries = (png_sPLT_entryp)png_malloc_warn( 1678 png_ptr, new_palette.nentries * (sizeof (png_sPLT_entry))); 1679 1680 if (new_palette.entries == NULL) 1681 { 1682 png_warning(png_ptr, "sPLT chunk requires too much memory"); 1683 return; 1684 } 1685 1686 #ifdef PNG_POINTER_INDEXING_SUPPORTED 1687 for (i = 0; i < new_palette.nentries; i++) 1688 { 1689 pp = new_palette.entries + i; 1690 1691 if (new_palette.depth == 8) 1692 { 1693 pp->red = *entry_start++; 1694 pp->green = *entry_start++; 1695 pp->blue = *entry_start++; 1696 pp->alpha = *entry_start++; 1697 } 1698 1699 else 1700 { 1701 pp->red = png_get_uint_16(entry_start); entry_start += 2; 1702 pp->green = png_get_uint_16(entry_start); entry_start += 2; 1703 pp->blue = png_get_uint_16(entry_start); entry_start += 2; 1704 pp->alpha = png_get_uint_16(entry_start); entry_start += 2; 1705 } 1706 1707 pp->frequency = png_get_uint_16(entry_start); entry_start += 2; 1708 } 1709 #else 1710 pp = new_palette.entries; 1711 1712 for (i = 0; i < new_palette.nentries; i++) 1713 { 1714 1715 if (new_palette.depth == 8) 1716 { 1717 pp[i].red = *entry_start++; 1718 pp[i].green = *entry_start++; 1719 pp[i].blue = *entry_start++; 1720 pp[i].alpha = *entry_start++; 1721 } 1722 1723 else 1724 { 1725 pp[i].red = png_get_uint_16(entry_start); entry_start += 2; 1726 pp[i].green = png_get_uint_16(entry_start); entry_start += 2; 1727 pp[i].blue = png_get_uint_16(entry_start); entry_start += 2; 1728 pp[i].alpha = png_get_uint_16(entry_start); entry_start += 2; 1729 } 1730 1731 pp[i].frequency = png_get_uint_16(entry_start); entry_start += 2; 1732 } 1733 #endif 1734 1735 /* Discard all chunk data except the name and stash that */ 1736 new_palette.name = (png_charp)buffer; 1737 1738 png_set_sPLT(png_ptr, info_ptr, &new_palette, 1); 1739 1740 png_free(png_ptr, new_palette.entries); 1741 } 1742 #endif /* PNG_READ_sPLT_SUPPORTED */ 1743 1744 #ifdef PNG_READ_tRNS_SUPPORTED 1745 void /* PRIVATE */ 1746 png_handle_tRNS(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 1747 { 1748 png_byte readbuf[PNG_MAX_PALETTE_LENGTH]; 1749 1750 png_debug(1, "in png_handle_tRNS"); 1751 1752 if (!(png_ptr->mode & PNG_HAVE_IHDR)) 1753 png_chunk_error(png_ptr, "missing IHDR"); 1754 1755 else if (png_ptr->mode & PNG_HAVE_IDAT) 1756 { 1757 png_crc_finish(png_ptr, length); 1758 png_chunk_benign_error(png_ptr, "out of place"); 1759 return; 1760 } 1761 1762 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS)) 1763 { 1764 png_crc_finish(png_ptr, length); 1765 png_chunk_benign_error(png_ptr, "duplicate"); 1766 return; 1767 } 1768 1769 if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY) 1770 { 1771 png_byte buf[2]; 1772 1773 if (length != 2) 1774 { 1775 png_crc_finish(png_ptr, length); 1776 png_chunk_benign_error(png_ptr, "invalid"); 1777 return; 1778 } 1779 1780 png_crc_read(png_ptr, buf, 2); 1781 png_ptr->num_trans = 1; 1782 png_ptr->trans_color.gray = png_get_uint_16(buf); 1783 } 1784 1785 else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB) 1786 { 1787 png_byte buf[6]; 1788 1789 if (length != 6) 1790 { 1791 png_crc_finish(png_ptr, length); 1792 png_chunk_benign_error(png_ptr, "invalid"); 1793 return; 1794 } 1795 1796 png_crc_read(png_ptr, buf, length); 1797 png_ptr->num_trans = 1; 1798 png_ptr->trans_color.red = png_get_uint_16(buf); 1799 png_ptr->trans_color.green = png_get_uint_16(buf + 2); 1800 png_ptr->trans_color.blue = png_get_uint_16(buf + 4); 1801 } 1802 1803 else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) 1804 { 1805 if (!(png_ptr->mode & PNG_HAVE_PLTE)) 1806 { 1807 /* TODO: is this actually an error in the ISO spec? */ 1808 png_crc_finish(png_ptr, length); 1809 png_chunk_benign_error(png_ptr, "out of place"); 1810 return; 1811 } 1812 1813 if (length > png_ptr->num_palette || length > PNG_MAX_PALETTE_LENGTH || 1814 length == 0) 1815 { 1816 png_crc_finish(png_ptr, length); 1817 png_chunk_benign_error(png_ptr, "invalid"); 1818 return; 1819 } 1820 1821 png_crc_read(png_ptr, readbuf, length); 1822 png_ptr->num_trans = (png_uint_16)length; 1823 } 1824 1825 else 1826 { 1827 png_crc_finish(png_ptr, length); 1828 png_chunk_benign_error(png_ptr, "invalid with alpha channel"); 1829 return; 1830 } 1831 1832 if (png_crc_finish(png_ptr, 0)) 1833 { 1834 png_ptr->num_trans = 0; 1835 return; 1836 } 1837 1838 /* TODO: this is a horrible side effect in the palette case because the 1839 * png_struct ends up with a pointer to the tRNS buffer owned by the 1840 * png_info. Fix this. 1841 */ 1842 png_set_tRNS(png_ptr, info_ptr, readbuf, png_ptr->num_trans, 1843 &(png_ptr->trans_color)); 1844 } 1845 #endif 1846 1847 #ifdef PNG_READ_bKGD_SUPPORTED 1848 void /* PRIVATE */ 1849 png_handle_bKGD(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 1850 { 1851 unsigned int truelen; 1852 png_byte buf[6]; 1853 png_color_16 background; 1854 1855 png_debug(1, "in png_handle_bKGD"); 1856 1857 if (!(png_ptr->mode & PNG_HAVE_IHDR)) 1858 png_chunk_error(png_ptr, "missing IHDR"); 1859 1860 else if ((png_ptr->mode & PNG_HAVE_IDAT) || 1861 (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE && 1862 !(png_ptr->mode & PNG_HAVE_PLTE))) 1863 { 1864 png_crc_finish(png_ptr, length); 1865 png_chunk_benign_error(png_ptr, "out of place"); 1866 return; 1867 } 1868 1869 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD)) 1870 { 1871 png_crc_finish(png_ptr, length); 1872 png_chunk_benign_error(png_ptr, "duplicate"); 1873 return; 1874 } 1875 1876 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) 1877 truelen = 1; 1878 1879 else if (png_ptr->color_type & PNG_COLOR_MASK_COLOR) 1880 truelen = 6; 1881 1882 else 1883 truelen = 2; 1884 1885 if (length != truelen) 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, buf, truelen); 1893 1894 if (png_crc_finish(png_ptr, 0)) 1895 return; 1896 1897 /* We convert the index value into RGB components so that we can allow 1898 * arbitrary RGB values for background when we have transparency, and 1899 * so it is easy to determine the RGB values of the background color 1900 * from the info_ptr struct. 1901 */ 1902 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) 1903 { 1904 background.index = buf[0]; 1905 1906 if (info_ptr && info_ptr->num_palette) 1907 { 1908 if (buf[0] >= info_ptr->num_palette) 1909 { 1910 png_chunk_benign_error(png_ptr, "invalid index"); 1911 return; 1912 } 1913 1914 background.red = (png_uint_16)png_ptr->palette[buf[0]].red; 1915 background.green = (png_uint_16)png_ptr->palette[buf[0]].green; 1916 background.blue = (png_uint_16)png_ptr->palette[buf[0]].blue; 1917 } 1918 1919 else 1920 background.red = background.green = background.blue = 0; 1921 1922 background.gray = 0; 1923 } 1924 1925 else if (!(png_ptr->color_type & PNG_COLOR_MASK_COLOR)) /* GRAY */ 1926 { 1927 background.index = 0; 1928 background.red = 1929 background.green = 1930 background.blue = 1931 background.gray = png_get_uint_16(buf); 1932 } 1933 1934 else 1935 { 1936 background.index = 0; 1937 background.red = png_get_uint_16(buf); 1938 background.green = png_get_uint_16(buf + 2); 1939 background.blue = png_get_uint_16(buf + 4); 1940 background.gray = 0; 1941 } 1942 1943 png_set_bKGD(png_ptr, info_ptr, &background); 1944 } 1945 #endif 1946 1947 #ifdef PNG_READ_hIST_SUPPORTED 1948 void /* PRIVATE */ 1949 png_handle_hIST(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 1950 { 1951 unsigned int num, i; 1952 png_uint_16 readbuf[PNG_MAX_PALETTE_LENGTH]; 1953 1954 png_debug(1, "in png_handle_hIST"); 1955 1956 if (!(png_ptr->mode & PNG_HAVE_IHDR)) 1957 png_chunk_error(png_ptr, "missing IHDR"); 1958 1959 else if ((png_ptr->mode & PNG_HAVE_IDAT) || !(png_ptr->mode & PNG_HAVE_PLTE)) 1960 { 1961 png_crc_finish(png_ptr, length); 1962 png_chunk_benign_error(png_ptr, "out of place"); 1963 return; 1964 } 1965 1966 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST)) 1967 { 1968 png_crc_finish(png_ptr, length); 1969 png_chunk_benign_error(png_ptr, "duplicate"); 1970 return; 1971 } 1972 1973 num = length / 2 ; 1974 1975 if (num != png_ptr->num_palette || num > PNG_MAX_PALETTE_LENGTH) 1976 { 1977 png_crc_finish(png_ptr, length); 1978 png_chunk_benign_error(png_ptr, "invalid"); 1979 return; 1980 } 1981 1982 for (i = 0; i < num; i++) 1983 { 1984 png_byte buf[2]; 1985 1986 png_crc_read(png_ptr, buf, 2); 1987 readbuf[i] = png_get_uint_16(buf); 1988 } 1989 1990 if (png_crc_finish(png_ptr, 0)) 1991 return; 1992 1993 png_set_hIST(png_ptr, info_ptr, readbuf); 1994 } 1995 #endif 1996 1997 #ifdef PNG_READ_pHYs_SUPPORTED 1998 void /* PRIVATE */ 1999 png_handle_pHYs(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 2000 { 2001 png_byte buf[9]; 2002 png_uint_32 res_x, res_y; 2003 int unit_type; 2004 2005 png_debug(1, "in png_handle_pHYs"); 2006 2007 if (!(png_ptr->mode & PNG_HAVE_IHDR)) 2008 png_chunk_error(png_ptr, "missing IHDR"); 2009 2010 else if (png_ptr->mode & PNG_HAVE_IDAT) 2011 { 2012 png_crc_finish(png_ptr, length); 2013 png_chunk_benign_error(png_ptr, "out of place"); 2014 return; 2015 } 2016 2017 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs)) 2018 { 2019 png_crc_finish(png_ptr, length); 2020 png_chunk_benign_error(png_ptr, "duplicate"); 2021 return; 2022 } 2023 2024 if (length != 9) 2025 { 2026 png_crc_finish(png_ptr, length); 2027 png_chunk_benign_error(png_ptr, "invalid"); 2028 return; 2029 } 2030 2031 png_crc_read(png_ptr, buf, 9); 2032 2033 if (png_crc_finish(png_ptr, 0)) 2034 return; 2035 2036 res_x = png_get_uint_32(buf); 2037 res_y = png_get_uint_32(buf + 4); 2038 unit_type = buf[8]; 2039 png_set_pHYs(png_ptr, info_ptr, res_x, res_y, unit_type); 2040 } 2041 #endif 2042 2043 #ifdef PNG_READ_oFFs_SUPPORTED 2044 void /* PRIVATE */ 2045 png_handle_oFFs(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 2046 { 2047 png_byte buf[9]; 2048 png_int_32 offset_x, offset_y; 2049 int unit_type; 2050 2051 png_debug(1, "in png_handle_oFFs"); 2052 2053 if (!(png_ptr->mode & PNG_HAVE_IHDR)) 2054 png_chunk_error(png_ptr, "missing IHDR"); 2055 2056 else if (png_ptr->mode & PNG_HAVE_IDAT) 2057 { 2058 png_crc_finish(png_ptr, length); 2059 png_chunk_benign_error(png_ptr, "out of place"); 2060 return; 2061 } 2062 2063 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs)) 2064 { 2065 png_crc_finish(png_ptr, length); 2066 png_chunk_benign_error(png_ptr, "duplicate"); 2067 return; 2068 } 2069 2070 if (length != 9) 2071 { 2072 png_crc_finish(png_ptr, length); 2073 png_chunk_benign_error(png_ptr, "invalid"); 2074 return; 2075 } 2076 2077 png_crc_read(png_ptr, buf, 9); 2078 2079 if (png_crc_finish(png_ptr, 0)) 2080 return; 2081 2082 offset_x = png_get_int_32(buf); 2083 offset_y = png_get_int_32(buf + 4); 2084 unit_type = buf[8]; 2085 png_set_oFFs(png_ptr, info_ptr, offset_x, offset_y, unit_type); 2086 } 2087 #endif 2088 2089 #ifdef PNG_READ_pCAL_SUPPORTED 2090 /* Read the pCAL chunk (described in the PNG Extensions document) */ 2091 void /* PRIVATE */ 2092 png_handle_pCAL(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 2093 { 2094 png_int_32 X0, X1; 2095 png_byte type, nparams; 2096 png_bytep buffer, buf, units, endptr; 2097 png_charpp params; 2098 int i; 2099 2100 png_debug(1, "in png_handle_pCAL"); 2101 2102 if (!(png_ptr->mode & PNG_HAVE_IHDR)) 2103 png_chunk_error(png_ptr, "missing IHDR"); 2104 2105 else if (png_ptr->mode & PNG_HAVE_IDAT) 2106 { 2107 png_crc_finish(png_ptr, length); 2108 png_chunk_benign_error(png_ptr, "out of place"); 2109 return; 2110 } 2111 2112 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pCAL)) 2113 { 2114 png_crc_finish(png_ptr, length); 2115 png_chunk_benign_error(png_ptr, "duplicate"); 2116 return; 2117 } 2118 2119 png_debug1(2, "Allocating and reading pCAL chunk data (%u bytes)", 2120 length + 1); 2121 2122 buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/); 2123 2124 if (buffer == NULL) 2125 { 2126 png_crc_finish(png_ptr, length); 2127 png_chunk_benign_error(png_ptr, "out of memory"); 2128 return; 2129 } 2130 2131 png_crc_read(png_ptr, buffer, length); 2132 2133 if (png_crc_finish(png_ptr, 0)) 2134 return; 2135 2136 buffer[length] = 0; /* Null terminate the last string */ 2137 2138 png_debug(3, "Finding end of pCAL purpose string"); 2139 for (buf = buffer; *buf; buf++) 2140 /* Empty loop */ ; 2141 2142 endptr = buffer + length; 2143 2144 /* We need to have at least 12 bytes after the purpose string 2145 * in order to get the parameter information. 2146 */ 2147 if (endptr <= buf + 12) 2148 { 2149 png_chunk_benign_error(png_ptr, "invalid"); 2150 return; 2151 } 2152 2153 png_debug(3, "Reading pCAL X0, X1, type, nparams, and units"); 2154 X0 = png_get_int_32((png_bytep)buf+1); 2155 X1 = png_get_int_32((png_bytep)buf+5); 2156 type = buf[9]; 2157 nparams = buf[10]; 2158 units = buf + 11; 2159 2160 png_debug(3, "Checking pCAL equation type and number of parameters"); 2161 /* Check that we have the right number of parameters for known 2162 * equation types. 2163 */ 2164 if ((type == PNG_EQUATION_LINEAR && nparams != 2) || 2165 (type == PNG_EQUATION_BASE_E && nparams != 3) || 2166 (type == PNG_EQUATION_ARBITRARY && nparams != 3) || 2167 (type == PNG_EQUATION_HYPERBOLIC && nparams != 4)) 2168 { 2169 png_chunk_benign_error(png_ptr, "invalid parameter count"); 2170 return; 2171 } 2172 2173 else if (type >= PNG_EQUATION_LAST) 2174 { 2175 png_chunk_benign_error(png_ptr, "unrecognized equation type"); 2176 } 2177 2178 for (buf = units; *buf; buf++) 2179 /* Empty loop to move past the units string. */ ; 2180 2181 png_debug(3, "Allocating pCAL parameters array"); 2182 2183 params = png_voidcast(png_charpp, png_malloc_warn(png_ptr, 2184 nparams * (sizeof (png_charp)))); 2185 2186 if (params == NULL) 2187 { 2188 png_chunk_benign_error(png_ptr, "out of memory"); 2189 return; 2190 } 2191 2192 /* Get pointers to the start of each parameter string. */ 2193 for (i = 0; i < nparams; i++) 2194 { 2195 buf++; /* Skip the null string terminator from previous parameter. */ 2196 2197 png_debug1(3, "Reading pCAL parameter %d", i); 2198 2199 for (params[i] = (png_charp)buf; buf <= endptr && *buf != 0; buf++) 2200 /* Empty loop to move past each parameter string */ ; 2201 2202 /* Make sure we haven't run out of data yet */ 2203 if (buf > endptr) 2204 { 2205 png_free(png_ptr, params); 2206 png_chunk_benign_error(png_ptr, "invalid data"); 2207 return; 2208 } 2209 } 2210 2211 png_set_pCAL(png_ptr, info_ptr, (png_charp)buffer, X0, X1, type, nparams, 2212 (png_charp)units, params); 2213 2214 png_free(png_ptr, params); 2215 } 2216 #endif 2217 2218 #ifdef PNG_READ_sCAL_SUPPORTED 2219 /* Read the sCAL chunk */ 2220 void /* PRIVATE */ 2221 png_handle_sCAL(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 2222 { 2223 png_bytep buffer; 2224 png_size_t i; 2225 int state; 2226 2227 png_debug(1, "in png_handle_sCAL"); 2228 2229 if (!(png_ptr->mode & PNG_HAVE_IHDR)) 2230 png_chunk_error(png_ptr, "missing IHDR"); 2231 2232 else if (png_ptr->mode & PNG_HAVE_IDAT) 2233 { 2234 png_crc_finish(png_ptr, length); 2235 png_chunk_benign_error(png_ptr, "out of place"); 2236 return; 2237 } 2238 2239 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sCAL)) 2240 { 2241 png_crc_finish(png_ptr, length); 2242 png_chunk_benign_error(png_ptr, "duplicate"); 2243 return; 2244 } 2245 2246 /* Need unit type, width, \0, height: minimum 4 bytes */ 2247 else if (length < 4) 2248 { 2249 png_crc_finish(png_ptr, length); 2250 png_chunk_benign_error(png_ptr, "invalid"); 2251 return; 2252 } 2253 2254 png_debug1(2, "Allocating and reading sCAL chunk data (%u bytes)", 2255 length + 1); 2256 2257 buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/); 2258 2259 if (buffer == NULL) 2260 { 2261 png_chunk_benign_error(png_ptr, "out of memory"); 2262 png_crc_finish(png_ptr, length); 2263 return; 2264 } 2265 2266 png_crc_read(png_ptr, buffer, length); 2267 buffer[length] = 0; /* Null terminate the last string */ 2268 2269 if (png_crc_finish(png_ptr, 0)) 2270 return; 2271 2272 /* Validate the unit. */ 2273 if (buffer[0] != 1 && buffer[0] != 2) 2274 { 2275 png_chunk_benign_error(png_ptr, "invalid unit"); 2276 return; 2277 } 2278 2279 /* Validate the ASCII numbers, need two ASCII numbers separated by 2280 * a '\0' and they need to fit exactly in the chunk data. 2281 */ 2282 i = 1; 2283 state = 0; 2284 2285 if (!png_check_fp_number((png_const_charp)buffer, length, &state, &i) || 2286 i >= length || buffer[i++] != 0) 2287 png_chunk_benign_error(png_ptr, "bad width format"); 2288 2289 else if (!PNG_FP_IS_POSITIVE(state)) 2290 png_chunk_benign_error(png_ptr, "non-positive width"); 2291 2292 else 2293 { 2294 png_size_t heighti = i; 2295 2296 state = 0; 2297 if (!png_check_fp_number((png_const_charp)buffer, length, &state, &i) || 2298 i != length) 2299 png_chunk_benign_error(png_ptr, "bad height format"); 2300 2301 else if (!PNG_FP_IS_POSITIVE(state)) 2302 png_chunk_benign_error(png_ptr, "non-positive height"); 2303 2304 else 2305 /* This is the (only) success case. */ 2306 png_set_sCAL_s(png_ptr, info_ptr, buffer[0], 2307 (png_charp)buffer+1, (png_charp)buffer+heighti); 2308 } 2309 } 2310 #endif 2311 2312 #ifdef PNG_READ_tIME_SUPPORTED 2313 void /* PRIVATE */ 2314 png_handle_tIME(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 2315 { 2316 png_byte buf[7]; 2317 png_time mod_time; 2318 2319 png_debug(1, "in png_handle_tIME"); 2320 2321 if (!(png_ptr->mode & PNG_HAVE_IHDR)) 2322 png_chunk_error(png_ptr, "missing IHDR"); 2323 2324 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tIME)) 2325 { 2326 png_crc_finish(png_ptr, length); 2327 png_chunk_benign_error(png_ptr, "duplicate"); 2328 return; 2329 } 2330 2331 if (png_ptr->mode & PNG_HAVE_IDAT) 2332 png_ptr->mode |= PNG_AFTER_IDAT; 2333 2334 if (length != 7) 2335 { 2336 png_crc_finish(png_ptr, length); 2337 png_chunk_benign_error(png_ptr, "invalid"); 2338 return; 2339 } 2340 2341 png_crc_read(png_ptr, buf, 7); 2342 2343 if (png_crc_finish(png_ptr, 0)) 2344 return; 2345 2346 mod_time.second = buf[6]; 2347 mod_time.minute = buf[5]; 2348 mod_time.hour = buf[4]; 2349 mod_time.day = buf[3]; 2350 mod_time.month = buf[2]; 2351 mod_time.year = png_get_uint_16(buf); 2352 2353 png_set_tIME(png_ptr, info_ptr, &mod_time); 2354 } 2355 #endif 2356 2357 #ifdef PNG_READ_tEXt_SUPPORTED 2358 /* Note: this does not properly handle chunks that are > 64K under DOS */ 2359 void /* PRIVATE */ 2360 png_handle_tEXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 2361 { 2362 png_text text_info; 2363 png_bytep buffer; 2364 png_charp key; 2365 png_charp text; 2366 png_uint_32 skip = 0; 2367 2368 png_debug(1, "in png_handle_tEXt"); 2369 2370 #ifdef PNG_USER_LIMITS_SUPPORTED 2371 if (png_ptr->user_chunk_cache_max != 0) 2372 { 2373 if (png_ptr->user_chunk_cache_max == 1) 2374 { 2375 png_crc_finish(png_ptr, length); 2376 return; 2377 } 2378 2379 if (--png_ptr->user_chunk_cache_max == 1) 2380 { 2381 png_crc_finish(png_ptr, length); 2382 png_chunk_benign_error(png_ptr, "no space in chunk cache"); 2383 return; 2384 } 2385 } 2386 #endif 2387 2388 if (!(png_ptr->mode & PNG_HAVE_IHDR)) 2389 png_chunk_error(png_ptr, "missing IHDR"); 2390 2391 if (png_ptr->mode & PNG_HAVE_IDAT) 2392 png_ptr->mode |= PNG_AFTER_IDAT; 2393 2394 #ifdef PNG_MAX_MALLOC_64K 2395 if (length > 65535U) 2396 { 2397 png_crc_finish(png_ptr, length); 2398 png_chunk_benign_error(png_ptr, "too large to fit in memory"); 2399 return; 2400 } 2401 #endif 2402 2403 buffer = png_read_buffer(png_ptr, length+1, 1/*warn*/); 2404 2405 if (buffer == NULL) 2406 { 2407 png_chunk_benign_error(png_ptr, "out of memory"); 2408 return; 2409 } 2410 2411 png_crc_read(png_ptr, buffer, length); 2412 2413 if (png_crc_finish(png_ptr, skip)) 2414 return; 2415 2416 key = (png_charp)buffer; 2417 key[length] = 0; 2418 2419 for (text = key; *text; text++) 2420 /* Empty loop to find end of key */ ; 2421 2422 if (text != key + length) 2423 text++; 2424 2425 text_info.compression = PNG_TEXT_COMPRESSION_NONE; 2426 text_info.key = key; 2427 text_info.lang = NULL; 2428 text_info.lang_key = NULL; 2429 text_info.itxt_length = 0; 2430 text_info.text = text; 2431 text_info.text_length = strlen(text); 2432 2433 if (png_set_text_2(png_ptr, info_ptr, &text_info, 1)) 2434 png_warning(png_ptr, "Insufficient memory to process text chunk"); 2435 } 2436 #endif 2437 2438 #ifdef PNG_READ_zTXt_SUPPORTED 2439 /* Note: this does not correctly handle chunks that are > 64K under DOS */ 2440 void /* PRIVATE */ 2441 png_handle_zTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 2442 { 2443 png_const_charp errmsg = NULL; 2444 png_bytep buffer; 2445 png_uint_32 keyword_length; 2446 2447 png_debug(1, "in png_handle_zTXt"); 2448 2449 #ifdef PNG_USER_LIMITS_SUPPORTED 2450 if (png_ptr->user_chunk_cache_max != 0) 2451 { 2452 if (png_ptr->user_chunk_cache_max == 1) 2453 { 2454 png_crc_finish(png_ptr, length); 2455 return; 2456 } 2457 2458 if (--png_ptr->user_chunk_cache_max == 1) 2459 { 2460 png_crc_finish(png_ptr, length); 2461 png_chunk_benign_error(png_ptr, "no space in chunk cache"); 2462 return; 2463 } 2464 } 2465 #endif 2466 2467 if (!(png_ptr->mode & PNG_HAVE_IHDR)) 2468 png_chunk_error(png_ptr, "missing IHDR"); 2469 2470 if (png_ptr->mode & PNG_HAVE_IDAT) 2471 png_ptr->mode |= PNG_AFTER_IDAT; 2472 2473 buffer = png_read_buffer(png_ptr, length, 2/*silent*/); 2474 2475 if (buffer == NULL) 2476 { 2477 png_crc_finish(png_ptr, length); 2478 png_chunk_benign_error(png_ptr, "out of memory"); 2479 return; 2480 } 2481 2482 png_crc_read(png_ptr, buffer, length); 2483 2484 if (png_crc_finish(png_ptr, 0)) 2485 return; 2486 2487 /* TODO: also check that the keyword contents match the spec! */ 2488 for (keyword_length = 0; 2489 keyword_length < length && buffer[keyword_length] != 0; 2490 ++keyword_length) 2491 /* Empty loop to find end of name */ ; 2492 2493 if (keyword_length > 79 || keyword_length < 1) 2494 errmsg = "bad keyword"; 2495 2496 /* zTXt must have some LZ data after the keyword, although it may expand to 2497 * zero bytes; we need a '\0' at the end of the keyword, the compression type 2498 * then the LZ data: 2499 */ 2500 else if (keyword_length + 3 > length) 2501 errmsg = "truncated"; 2502 2503 else if (buffer[keyword_length+1] != PNG_COMPRESSION_TYPE_BASE) 2504 errmsg = "unknown compression type"; 2505 2506 else 2507 { 2508 png_alloc_size_t uncompressed_length = PNG_SIZE_MAX; 2509 2510 /* TODO: at present png_decompress_chunk imposes a single application 2511 * level memory limit, this should be split to different values for iCCP 2512 * and text chunks. 2513 */ 2514 if (png_decompress_chunk(png_ptr, length, keyword_length+2, 2515 &uncompressed_length, 1/*terminate*/) == Z_STREAM_END) 2516 { 2517 png_text text; 2518 2519 /* It worked; png_ptr->read_buffer now looks like a tEXt chunk except 2520 * for the extra compression type byte and the fact that it isn't 2521 * necessarily '\0' terminated. 2522 */ 2523 buffer = png_ptr->read_buffer; 2524 buffer[uncompressed_length+(keyword_length+2)] = 0; 2525 2526 text.compression = PNG_TEXT_COMPRESSION_zTXt; 2527 text.key = (png_charp)buffer; 2528 text.text = (png_charp)(buffer + keyword_length+2); 2529 text.text_length = uncompressed_length; 2530 text.itxt_length = 0; 2531 text.lang = NULL; 2532 text.lang_key = NULL; 2533 2534 if (png_set_text_2(png_ptr, info_ptr, &text, 1)) 2535 errmsg = "insufficient memory"; 2536 } 2537 2538 else 2539 errmsg = png_ptr->zstream.msg; 2540 } 2541 2542 if (errmsg != NULL) 2543 png_chunk_benign_error(png_ptr, errmsg); 2544 } 2545 #endif 2546 2547 #ifdef PNG_READ_iTXt_SUPPORTED 2548 /* Note: this does not correctly handle chunks that are > 64K under DOS */ 2549 void /* PRIVATE */ 2550 png_handle_iTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 2551 { 2552 png_const_charp errmsg = NULL; 2553 png_bytep buffer; 2554 png_uint_32 prefix_length; 2555 2556 png_debug(1, "in png_handle_iTXt"); 2557 2558 #ifdef PNG_USER_LIMITS_SUPPORTED 2559 if (png_ptr->user_chunk_cache_max != 0) 2560 { 2561 if (png_ptr->user_chunk_cache_max == 1) 2562 { 2563 png_crc_finish(png_ptr, length); 2564 return; 2565 } 2566 2567 if (--png_ptr->user_chunk_cache_max == 1) 2568 { 2569 png_crc_finish(png_ptr, length); 2570 png_chunk_benign_error(png_ptr, "no space in chunk cache"); 2571 return; 2572 } 2573 } 2574 #endif 2575 2576 if (!(png_ptr->mode & PNG_HAVE_IHDR)) 2577 png_chunk_error(png_ptr, "missing IHDR"); 2578 2579 if (png_ptr->mode & PNG_HAVE_IDAT) 2580 png_ptr->mode |= PNG_AFTER_IDAT; 2581 2582 buffer = png_read_buffer(png_ptr, length+1, 1/*warn*/); 2583 2584 if (buffer == NULL) 2585 { 2586 png_crc_finish(png_ptr, length); 2587 png_chunk_benign_error(png_ptr, "out of memory"); 2588 return; 2589 } 2590 2591 png_crc_read(png_ptr, buffer, length); 2592 2593 if (png_crc_finish(png_ptr, 0)) 2594 return; 2595 2596 /* First the keyword. */ 2597 for (prefix_length=0; 2598 prefix_length < length && buffer[prefix_length] != 0; 2599 ++prefix_length) 2600 /* Empty loop */ ; 2601 2602 /* Perform a basic check on the keyword length here. */ 2603 if (prefix_length > 79 || prefix_length < 1) 2604 errmsg = "bad keyword"; 2605 2606 /* Expect keyword, compression flag, compression type, language, translated 2607 * keyword (both may be empty but are 0 terminated) then the text, which may 2608 * be empty. 2609 */ 2610 else if (prefix_length + 5 > length) 2611 errmsg = "truncated"; 2612 2613 else if (buffer[prefix_length+1] == 0 || 2614 (buffer[prefix_length+1] == 1 && 2615 buffer[prefix_length+2] == PNG_COMPRESSION_TYPE_BASE)) 2616 { 2617 int compressed = buffer[prefix_length+1] != 0; 2618 png_uint_32 language_offset, translated_keyword_offset; 2619 png_alloc_size_t uncompressed_length = 0; 2620 2621 /* Now the language tag */ 2622 prefix_length += 3; 2623 language_offset = prefix_length; 2624 2625 for (; prefix_length < length && buffer[prefix_length] != 0; 2626 ++prefix_length) 2627 /* Empty loop */ ; 2628 2629 /* WARNING: the length may be invalid here, this is checked below. */ 2630 translated_keyword_offset = ++prefix_length; 2631 2632 for (; prefix_length < length && buffer[prefix_length] != 0; 2633 ++prefix_length) 2634 /* Empty loop */ ; 2635 2636 /* prefix_length should now be at the trailing '\0' of the translated 2637 * keyword, but it may already be over the end. None of this arithmetic 2638 * can overflow because chunks are at most 2^31 bytes long, but on 16-bit 2639 * systems the available allocaton may overflow. 2640 */ 2641 ++prefix_length; 2642 2643 if (!compressed && prefix_length <= length) 2644 uncompressed_length = length - prefix_length; 2645 2646 else if (compressed && prefix_length < length) 2647 { 2648 uncompressed_length = PNG_SIZE_MAX; 2649 2650 /* TODO: at present png_decompress_chunk imposes a single application 2651 * level memory limit, this should be split to different values for 2652 * iCCP and text chunks. 2653 */ 2654 if (png_decompress_chunk(png_ptr, length, prefix_length, 2655 &uncompressed_length, 1/*terminate*/) == Z_STREAM_END) 2656 buffer = png_ptr->read_buffer; 2657 2658 else 2659 errmsg = png_ptr->zstream.msg; 2660 } 2661 2662 else 2663 errmsg = "truncated"; 2664 2665 if (errmsg == NULL) 2666 { 2667 png_text text; 2668 2669 buffer[uncompressed_length+prefix_length] = 0; 2670 2671 if (compressed) 2672 text.compression = PNG_ITXT_COMPRESSION_NONE; 2673 2674 else 2675 text.compression = PNG_ITXT_COMPRESSION_zTXt; 2676 2677 text.key = (png_charp)buffer; 2678 text.lang = (png_charp)buffer + language_offset; 2679 text.lang_key = (png_charp)buffer + translated_keyword_offset; 2680 text.text = (png_charp)buffer + prefix_length; 2681 text.text_length = 0; 2682 text.itxt_length = uncompressed_length; 2683 2684 if (png_set_text_2(png_ptr, info_ptr, &text, 1)) 2685 errmsg = "insufficient memory"; 2686 } 2687 } 2688 2689 else 2690 errmsg = "bad compression info"; 2691 2692 if (errmsg != NULL) 2693 png_chunk_benign_error(png_ptr, errmsg); 2694 } 2695 #endif 2696 2697 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED 2698 /* Utility function for png_handle_unknown; set up png_ptr::unknown_chunk */ 2699 static int 2700 png_cache_unknown_chunk(png_structrp png_ptr, png_uint_32 length) 2701 { 2702 png_alloc_size_t limit = PNG_SIZE_MAX; 2703 2704 if (png_ptr->unknown_chunk.data != NULL) 2705 { 2706 png_free(png_ptr, png_ptr->unknown_chunk.data); 2707 png_ptr->unknown_chunk.data = NULL; 2708 } 2709 2710 # ifdef PNG_SET_CHUNK_MALLOC_LIMIT_SUPPORTED 2711 if (png_ptr->user_chunk_malloc_max > 0 && 2712 png_ptr->user_chunk_malloc_max < limit) 2713 limit = png_ptr->user_chunk_malloc_max; 2714 2715 # elif PNG_USER_CHUNK_MALLOC_MAX > 0 2716 if (PNG_USER_CHUNK_MALLOC_MAX < limit) 2717 limit = PNG_USER_CHUNK_MALLOC_MAX; 2718 # endif 2719 2720 if (length <= limit) 2721 { 2722 PNG_CSTRING_FROM_CHUNK(png_ptr->unknown_chunk.name, png_ptr->chunk_name); 2723 /* The following is safe because of the PNG_SIZE_MAX init above */ 2724 png_ptr->unknown_chunk.size = (png_size_t)length/*SAFE*/; 2725 /* 'mode' is a flag array, only the bottom four bits matter here */ 2726 png_ptr->unknown_chunk.location = (png_byte)png_ptr->mode/*SAFE*/; 2727 2728 if (length == 0) 2729 png_ptr->unknown_chunk.data = NULL; 2730 2731 else 2732 { 2733 /* Do a 'warn' here - it is handled below. */ 2734 png_ptr->unknown_chunk.data = png_voidcast(png_bytep, 2735 png_malloc_warn(png_ptr, length)); 2736 } 2737 } 2738 2739 if (png_ptr->unknown_chunk.data == NULL && length > 0) 2740 { 2741 /* This is benign because we clean up correctly */ 2742 png_crc_finish(png_ptr, length); 2743 png_chunk_benign_error(png_ptr, "unknown chunk exceeds memory limits"); 2744 return 0; 2745 } 2746 2747 else 2748 { 2749 if (length > 0) 2750 png_crc_read(png_ptr, png_ptr->unknown_chunk.data, length); 2751 png_crc_finish(png_ptr, 0); 2752 return 1; 2753 } 2754 } 2755 #endif /* PNG_READ_UNKNOWN_CHUNKS_SUPPORTED */ 2756 2757 /* Handle an unknown, or known but disabled, chunk */ 2758 void /* PRIVATE */ 2759 png_handle_unknown(png_structrp png_ptr, png_inforp info_ptr, 2760 png_uint_32 length, int keep) 2761 { 2762 int handled = 0; /* the chunk was handled */ 2763 2764 png_debug(1, "in png_handle_unknown"); 2765 2766 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED 2767 /* NOTE: this code is based on the code in libpng-1.4.12 except for fixing 2768 * the bug which meant that setting a non-default behavior for a specific 2769 * chunk would be ignored (the default was always used unless a user 2770 * callback was installed). 2771 * 2772 * 'keep' is the value from the png_chunk_unknown_handling, the setting for 2773 * this specific chunk_name, if PNG_HANDLE_AS_UNKNOWN_SUPPORTED, if not it 2774 * will always be PNG_HANDLE_CHUNK_AS_DEFAULT and it needs to be set here. 2775 * This is just an optimization to avoid multiple calls to the lookup 2776 * function. 2777 */ 2778 # ifndef PNG_HANDLE_AS_UNKNOWN_SUPPORTED 2779 # ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED 2780 keep = png_chunk_unknown_handling(png_ptr, png_ptr->chunk_name); 2781 # endif 2782 # endif 2783 2784 /* One of the following methods will read the chunk or skip it (at least one 2785 * of these is always defined because this is the only way to switch on 2786 * PNG_READ_UNKNOWN_CHUNKS_SUPPORTED) 2787 */ 2788 # ifdef PNG_READ_USER_CHUNKS_SUPPORTED 2789 /* The user callback takes precedence over the chunk keep value, but the 2790 * keep value is still required to validate a save of a critical chunk. 2791 */ 2792 if (png_ptr->read_user_chunk_fn != NULL) 2793 { 2794 if (png_cache_unknown_chunk(png_ptr, length)) 2795 { 2796 /* Callback to user unknown chunk handler */ 2797 int ret = (*(png_ptr->read_user_chunk_fn))(png_ptr, 2798 &png_ptr->unknown_chunk); 2799 2800 /* ret is: 2801 * negative: An error occured, png_chunk_error will be called. 2802 * zero: The chunk was not handled, the chunk will be discarded 2803 * unless png_set_keep_unknown_chunks has been used to set 2804 * a 'keep' behavior for this particular chunk, in which 2805 * case that will be used. A critical chunk will cause an 2806 * error at this point unless it is to be saved. 2807 * positive: The chunk was handled, libpng will ignore/discard it. 2808 */ 2809 if (ret < 0) 2810 png_chunk_error(png_ptr, "error in user chunk"); 2811 2812 else if (ret == 0) 2813 { 2814 /* If the keep value is 'default' or 'never' override it, but 2815 * still error out on critical chunks unless the keep value is 2816 * 'always' While this is weird it is the behavior in 1.4.12. 2817 * A possible improvement would be to obey the value set for the 2818 * chunk, but this would be an API change that would probably 2819 * damage some applications. 2820 * 2821 * The png_app_warning below catches the case that matters, where 2822 * the application has not set specific save or ignore for this 2823 * chunk or global save or ignore. 2824 */ 2825 if (keep < PNG_HANDLE_CHUNK_IF_SAFE) 2826 { 2827 # ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED 2828 if (png_ptr->unknown_default < PNG_HANDLE_CHUNK_IF_SAFE) 2829 { 2830 png_chunk_warning(png_ptr, "Saving unknown chunk:"); 2831 png_app_warning(png_ptr, 2832 "forcing save of an unhandled chunk;" 2833 " please call png_set_keep_unknown_chunks"); 2834 /* with keep = PNG_HANDLE_CHUNK_IF_SAFE */ 2835 } 2836 # endif 2837 keep = PNG_HANDLE_CHUNK_IF_SAFE; 2838 } 2839 } 2840 2841 else /* chunk was handled */ 2842 { 2843 handled = 1; 2844 /* Critical chunks can be safely discarded at this point. */ 2845 keep = PNG_HANDLE_CHUNK_NEVER; 2846 } 2847 } 2848 2849 else 2850 keep = PNG_HANDLE_CHUNK_NEVER; /* insufficient memory */ 2851 } 2852 2853 else 2854 /* Use the SAVE_UNKNOWN_CHUNKS code or skip the chunk */ 2855 # endif /* PNG_READ_USER_CHUNKS_SUPPORTED */ 2856 2857 # ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED 2858 { 2859 /* keep is currently just the per-chunk setting, if there was no 2860 * setting change it to the global default now (not that this may 2861 * still be AS_DEFAULT) then obtain the cache of the chunk if required, 2862 * if not simply skip the chunk. 2863 */ 2864 if (keep == PNG_HANDLE_CHUNK_AS_DEFAULT) 2865 keep = png_ptr->unknown_default; 2866 2867 if (keep == PNG_HANDLE_CHUNK_ALWAYS || 2868 (keep == PNG_HANDLE_CHUNK_IF_SAFE && 2869 PNG_CHUNK_ANCILLARY(png_ptr->chunk_name))) 2870 { 2871 if (!png_cache_unknown_chunk(png_ptr, length)) 2872 keep = PNG_HANDLE_CHUNK_NEVER; 2873 } 2874 2875 else 2876 png_crc_finish(png_ptr, length); 2877 } 2878 # else 2879 # ifndef PNG_READ_USER_CHUNKS_SUPPORTED 2880 # error no method to support READ_UNKNOWN_CHUNKS 2881 # endif 2882 2883 { 2884 /* If here there is no read callback pointer set and no support is 2885 * compiled in to just save the unknown chunks, so simply skip this 2886 * chunk. If 'keep' is something other than AS_DEFAULT or NEVER then 2887 * the app has erroneously asked for unknown chunk saving when there 2888 * is no support. 2889 */ 2890 if (keep > PNG_HANDLE_CHUNK_NEVER) 2891 png_app_error(png_ptr, "no unknown chunk support available"); 2892 2893 png_crc_finish(png_ptr, length); 2894 } 2895 # endif 2896 2897 # ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED 2898 /* Now store the chunk in the chunk list if appropriate, and if the limits 2899 * permit it. 2900 */ 2901 if (keep == PNG_HANDLE_CHUNK_ALWAYS || 2902 (keep == PNG_HANDLE_CHUNK_IF_SAFE && 2903 PNG_CHUNK_ANCILLARY(png_ptr->chunk_name))) 2904 { 2905 # ifdef PNG_USER_LIMITS_SUPPORTED 2906 switch (png_ptr->user_chunk_cache_max) 2907 { 2908 case 2: 2909 png_ptr->user_chunk_cache_max = 1; 2910 png_chunk_benign_error(png_ptr, "no space in chunk cache"); 2911 /* FALL THROUGH */ 2912 case 1: 2913 /* NOTE: prior to 1.6.0 this case resulted in an unknown critical 2914 * chunk being skipped, now there will be a hard error below. 2915 */ 2916 break; 2917 2918 default: /* not at limit */ 2919 --(png_ptr->user_chunk_cache_max); 2920 /* FALL THROUGH */ 2921 case 0: /* no limit */ 2922 # endif /* PNG_USER_LIMITS_SUPPORTED */ 2923 /* Here when the limit isn't reached or when limits are compiled 2924 * out; store the chunk. 2925 */ 2926 png_set_unknown_chunks(png_ptr, info_ptr, 2927 &png_ptr->unknown_chunk, 1); 2928 handled = 1; 2929 # ifdef PNG_USER_LIMITS_SUPPORTED 2930 break; 2931 } 2932 # endif 2933 } 2934 # else /* no store support! */ 2935 PNG_UNUSED(info_ptr) 2936 # error untested code (reading unknown chunks with no store support) 2937 # endif 2938 2939 /* Regardless of the error handling below the cached data (if any) can be 2940 * freed now. Notice that the data is not freed if there is a png_error, but 2941 * it will be freed by destroy_read_struct. 2942 */ 2943 if (png_ptr->unknown_chunk.data != NULL) 2944 png_free(png_ptr, png_ptr->unknown_chunk.data); 2945 png_ptr->unknown_chunk.data = NULL; 2946 2947 #else /* !PNG_READ_UNKNOWN_CHUNKS_SUPPORTED */ 2948 /* There is no support to read an unknown chunk, so just skip it. */ 2949 png_crc_finish(png_ptr, length); 2950 PNG_UNUSED(info_ptr) 2951 PNG_UNUSED(keep) 2952 #endif /* !PNG_READ_UNKNOWN_CHUNKS_SUPPORTED */ 2953 2954 /* Check for unhandled critical chunks */ 2955 if (!handled && PNG_CHUNK_CRITICAL(png_ptr->chunk_name)) 2956 png_chunk_error(png_ptr, "unhandled critical chunk"); 2957 } 2958 2959 /* This function is called to verify that a chunk name is valid. 2960 * This function can't have the "critical chunk check" incorporated 2961 * into it, since in the future we will need to be able to call user 2962 * functions to handle unknown critical chunks after we check that 2963 * the chunk name itself is valid. 2964 */ 2965 2966 /* Bit hacking: the test for an invalid byte in the 4 byte chunk name is: 2967 * 2968 * ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97)) 2969 */ 2970 2971 void /* PRIVATE */ 2972 png_check_chunk_name(png_structrp png_ptr, png_uint_32 chunk_name) 2973 { 2974 int i; 2975 2976 png_debug(1, "in png_check_chunk_name"); 2977 2978 for (i=1; i<=4; ++i) 2979 { 2980 int c = chunk_name & 0xff; 2981 2982 if (c < 65 || c > 122 || (c > 90 && c < 97)) 2983 png_chunk_error(png_ptr, "invalid chunk type"); 2984 2985 chunk_name >>= 8; 2986 } 2987 } 2988 2989 /* Combines the row recently read in with the existing pixels in the row. This 2990 * routine takes care of alpha and transparency if requested. This routine also 2991 * handles the two methods of progressive display of interlaced images, 2992 * depending on the 'display' value; if 'display' is true then the whole row 2993 * (dp) is filled from the start by replicating the available pixels. If 2994 * 'display' is false only those pixels present in the pass are filled in. 2995 */ 2996 void /* PRIVATE */ 2997 png_combine_row(png_const_structrp png_ptr, png_bytep dp, int display) 2998 { 2999 unsigned int pixel_depth = png_ptr->transformed_pixel_depth; 3000 png_const_bytep sp = png_ptr->row_buf + 1; 3001 png_uint_32 row_width = png_ptr->width; 3002 unsigned int pass = png_ptr->pass; 3003 png_bytep end_ptr = 0; 3004 png_byte end_byte = 0; 3005 unsigned int end_mask; 3006 3007 png_debug(1, "in png_combine_row"); 3008 3009 /* Added in 1.5.6: it should not be possible to enter this routine until at 3010 * least one row has been read from the PNG data and transformed. 3011 */ 3012 if (pixel_depth == 0) 3013 png_error(png_ptr, "internal row logic error"); 3014 3015 /* Added in 1.5.4: the pixel depth should match the information returned by 3016 * any call to png_read_update_info at this point. Do not continue if we got 3017 * this wrong. 3018 */ 3019 if (png_ptr->info_rowbytes != 0 && png_ptr->info_rowbytes != 3020 PNG_ROWBYTES(pixel_depth, row_width)) 3021 png_error(png_ptr, "internal row size calculation error"); 3022 3023 /* Don't expect this to ever happen: */ 3024 if (row_width == 0) 3025 png_error(png_ptr, "internal row width error"); 3026 3027 /* Preserve the last byte in cases where only part of it will be overwritten, 3028 * the multiply below may overflow, we don't care because ANSI-C guarantees 3029 * we get the low bits. 3030 */ 3031 end_mask = (pixel_depth * row_width) & 7; 3032 if (end_mask != 0) 3033 { 3034 /* end_ptr == NULL is a flag to say do nothing */ 3035 end_ptr = dp + PNG_ROWBYTES(pixel_depth, row_width) - 1; 3036 end_byte = *end_ptr; 3037 # ifdef PNG_READ_PACKSWAP_SUPPORTED 3038 if (png_ptr->transformations & PNG_PACKSWAP) /* little-endian byte */ 3039 end_mask = 0xff << end_mask; 3040 3041 else /* big-endian byte */ 3042 # endif 3043 end_mask = 0xff >> end_mask; 3044 /* end_mask is now the bits to *keep* from the destination row */ 3045 } 3046 3047 /* For non-interlaced images this reduces to a memcpy(). A memcpy() 3048 * will also happen if interlacing isn't supported or if the application 3049 * does not call png_set_interlace_handling(). In the latter cases the 3050 * caller just gets a sequence of the unexpanded rows from each interlace 3051 * pass. 3052 */ 3053 #ifdef PNG_READ_INTERLACING_SUPPORTED 3054 if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE) && 3055 pass < 6 && (display == 0 || 3056 /* The following copies everything for 'display' on passes 0, 2 and 4. */ 3057 (display == 1 && (pass & 1) != 0))) 3058 { 3059 /* Narrow images may have no bits in a pass; the caller should handle 3060 * this, but this test is cheap: 3061 */ 3062 if (row_width <= PNG_PASS_START_COL(pass)) 3063 return; 3064 3065 if (pixel_depth < 8) 3066 { 3067 /* For pixel depths up to 4 bpp the 8-pixel mask can be expanded to fit 3068 * into 32 bits, then a single loop over the bytes using the four byte 3069 * values in the 32-bit mask can be used. For the 'display' option the 3070 * expanded mask may also not require any masking within a byte. To 3071 * make this work the PACKSWAP option must be taken into account - it 3072 * simply requires the pixels to be reversed in each byte. 3073 * 3074 * The 'regular' case requires a mask for each of the first 6 passes, 3075 * the 'display' case does a copy for the even passes in the range 3076 * 0..6. This has already been handled in the test above. 3077 * 3078 * The masks are arranged as four bytes with the first byte to use in 3079 * the lowest bits (little-endian) regardless of the order (PACKSWAP or 3080 * not) of the pixels in each byte. 3081 * 3082 * NOTE: the whole of this logic depends on the caller of this function 3083 * only calling it on rows appropriate to the pass. This function only 3084 * understands the 'x' logic; the 'y' logic is handled by the caller. 3085 * 3086 * The following defines allow generation of compile time constant bit 3087 * masks for each pixel depth and each possibility of swapped or not 3088 * swapped bytes. Pass 'p' is in the range 0..6; 'x', a pixel index, 3089 * is in the range 0..7; and the result is 1 if the pixel is to be 3090 * copied in the pass, 0 if not. 'S' is for the sparkle method, 'B' 3091 * for the block method. 3092 * 3093 * With some compilers a compile time expression of the general form: 3094 * 3095 * (shift >= 32) ? (a >> (shift-32)) : (b >> shift) 3096 * 3097 * Produces warnings with values of 'shift' in the range 33 to 63 3098 * because the right hand side of the ?: expression is evaluated by 3099 * the compiler even though it isn't used. Microsoft Visual C (various 3100 * versions) and the Intel C compiler are known to do this. To avoid 3101 * this the following macros are used in 1.5.6. This is a temporary 3102 * solution to avoid destabilizing the code during the release process. 3103 */ 3104 # if PNG_USE_COMPILE_TIME_MASKS 3105 # define PNG_LSR(x,s) ((x)>>((s) & 0x1f)) 3106 # define PNG_LSL(x,s) ((x)<<((s) & 0x1f)) 3107 # else 3108 # define PNG_LSR(x,s) ((x)>>(s)) 3109 # define PNG_LSL(x,s) ((x)<<(s)) 3110 # endif 3111 # define S_COPY(p,x) (((p)<4 ? PNG_LSR(0x80088822,(3-(p))*8+(7-(x))) :\ 3112 PNG_LSR(0xaa55ff00,(7-(p))*8+(7-(x)))) & 1) 3113 # define B_COPY(p,x) (((p)<4 ? PNG_LSR(0xff0fff33,(3-(p))*8+(7-(x))) :\ 3114 PNG_LSR(0xff55ff00,(7-(p))*8+(7-(x)))) & 1) 3115 3116 /* Return a mask for pass 'p' pixel 'x' at depth 'd'. The mask is 3117 * little endian - the first pixel is at bit 0 - however the extra 3118 * parameter 's' can be set to cause the mask position to be swapped 3119 * within each byte, to match the PNG format. This is done by XOR of 3120 * the shift with 7, 6 or 4 for bit depths 1, 2 and 4. 3121 */ 3122 # define PIXEL_MASK(p,x,d,s) \ 3123 (PNG_LSL(((PNG_LSL(1U,(d)))-1),(((x)*(d))^((s)?8-(d):0)))) 3124 3125 /* Hence generate the appropriate 'block' or 'sparkle' pixel copy mask. 3126 */ 3127 # define S_MASKx(p,x,d,s) (S_COPY(p,x)?PIXEL_MASK(p,x,d,s):0) 3128 # define B_MASKx(p,x,d,s) (B_COPY(p,x)?PIXEL_MASK(p,x,d,s):0) 3129 3130 /* Combine 8 of these to get the full mask. For the 1-bpp and 2-bpp 3131 * cases the result needs replicating, for the 4-bpp case the above 3132 * generates a full 32 bits. 3133 */ 3134 # define MASK_EXPAND(m,d) ((m)*((d)==1?0x01010101:((d)==2?0x00010001:1))) 3135 3136 # define S_MASK(p,d,s) MASK_EXPAND(S_MASKx(p,0,d,s) + S_MASKx(p,1,d,s) +\ 3137 S_MASKx(p,2,d,s) + S_MASKx(p,3,d,s) + S_MASKx(p,4,d,s) +\ 3138 S_MASKx(p,5,d,s) + S_MASKx(p,6,d,s) + S_MASKx(p,7,d,s), d) 3139 3140 # define B_MASK(p,d,s) MASK_EXPAND(B_MASKx(p,0,d,s) + B_MASKx(p,1,d,s) +\ 3141 B_MASKx(p,2,d,s) + B_MASKx(p,3,d,s) + B_MASKx(p,4,d,s) +\ 3142 B_MASKx(p,5,d,s) + B_MASKx(p,6,d,s) + B_MASKx(p,7,d,s), d) 3143 3144 #if PNG_USE_COMPILE_TIME_MASKS 3145 /* Utility macros to construct all the masks for a depth/swap 3146 * combination. The 's' parameter says whether the format is PNG 3147 * (big endian bytes) or not. Only the three odd-numbered passes are 3148 * required for the display/block algorithm. 3149 */ 3150 # define S_MASKS(d,s) { S_MASK(0,d,s), S_MASK(1,d,s), S_MASK(2,d,s),\ 3151 S_MASK(3,d,s), S_MASK(4,d,s), S_MASK(5,d,s) } 3152 3153 # define B_MASKS(d,s) { B_MASK(1,d,s), S_MASK(3,d,s), S_MASK(5,d,s) } 3154 3155 # define DEPTH_INDEX(d) ((d)==1?0:((d)==2?1:2)) 3156 3157 /* Hence the pre-compiled masks indexed by PACKSWAP (or not), depth and 3158 * then pass: 3159 */ 3160 static PNG_CONST png_uint_32 row_mask[2/*PACKSWAP*/][3/*depth*/][6] = 3161 { 3162 /* Little-endian byte masks for PACKSWAP */ 3163 { S_MASKS(1,0), S_MASKS(2,0), S_MASKS(4,0) }, 3164 /* Normal (big-endian byte) masks - PNG format */ 3165 { S_MASKS(1,1), S_MASKS(2,1), S_MASKS(4,1) } 3166 }; 3167 3168 /* display_mask has only three entries for the odd passes, so index by 3169 * pass>>1. 3170 */ 3171 static PNG_CONST png_uint_32 display_mask[2][3][3] = 3172 { 3173 /* Little-endian byte masks for PACKSWAP */ 3174 { B_MASKS(1,0), B_MASKS(2,0), B_MASKS(4,0) }, 3175 /* Normal (big-endian byte) masks - PNG format */ 3176 { B_MASKS(1,1), B_MASKS(2,1), B_MASKS(4,1) } 3177 }; 3178 3179 # define MASK(pass,depth,display,png)\ 3180 ((display)?display_mask[png][DEPTH_INDEX(depth)][pass>>1]:\ 3181 row_mask[png][DEPTH_INDEX(depth)][pass]) 3182 3183 #else /* !PNG_USE_COMPILE_TIME_MASKS */ 3184 /* This is the runtime alternative: it seems unlikely that this will 3185 * ever be either smaller or faster than the compile time approach. 3186 */ 3187 # define MASK(pass,depth,display,png)\ 3188 ((display)?B_MASK(pass,depth,png):S_MASK(pass,depth,png)) 3189 #endif /* !PNG_USE_COMPILE_TIME_MASKS */ 3190 3191 /* Use the appropriate mask to copy the required bits. In some cases 3192 * the byte mask will be 0 or 0xff, optimize these cases. row_width is 3193 * the number of pixels, but the code copies bytes, so it is necessary 3194 * to special case the end. 3195 */ 3196 png_uint_32 pixels_per_byte = 8 / pixel_depth; 3197 png_uint_32 mask; 3198 3199 # ifdef PNG_READ_PACKSWAP_SUPPORTED 3200 if (png_ptr->transformations & PNG_PACKSWAP) 3201 mask = MASK(pass, pixel_depth, display, 0); 3202 3203 else 3204 # endif 3205 mask = MASK(pass, pixel_depth, display, 1); 3206 3207 for (;;) 3208 { 3209 png_uint_32 m; 3210 3211 /* It doesn't matter in the following if png_uint_32 has more than 3212 * 32 bits because the high bits always match those in m<<24; it is, 3213 * however, essential to use OR here, not +, because of this. 3214 */ 3215 m = mask; 3216 mask = (m >> 8) | (m << 24); /* rotate right to good compilers */ 3217 m &= 0xff; 3218 3219 if (m != 0) /* something to copy */ 3220 { 3221 if (m != 0xff) 3222 *dp = (png_byte)((*dp & ~m) | (*sp & m)); 3223 else 3224 *dp = *sp; 3225 } 3226 3227 /* NOTE: this may overwrite the last byte with garbage if the image 3228 * is not an exact number of bytes wide; libpng has always done 3229 * this. 3230 */ 3231 if (row_width <= pixels_per_byte) 3232 break; /* May need to restore part of the last byte */ 3233 3234 row_width -= pixels_per_byte; 3235 ++dp; 3236 ++sp; 3237 } 3238 } 3239 3240 else /* pixel_depth >= 8 */ 3241 { 3242 unsigned int bytes_to_copy, bytes_to_jump; 3243 3244 /* Validate the depth - it must be a multiple of 8 */ 3245 if (pixel_depth & 7) 3246 png_error(png_ptr, "invalid user transform pixel depth"); 3247 3248 pixel_depth >>= 3; /* now in bytes */ 3249 row_width *= pixel_depth; 3250 3251 /* Regardless of pass number the Adam 7 interlace always results in a 3252 * fixed number of pixels to copy then to skip. There may be a 3253 * different number of pixels to skip at the start though. 3254 */ 3255 { 3256 unsigned int offset = PNG_PASS_START_COL(pass) * pixel_depth; 3257 3258 row_width -= offset; 3259 dp += offset; 3260 sp += offset; 3261 } 3262 3263 /* Work out the bytes to copy. */ 3264 if (display) 3265 { 3266 /* When doing the 'block' algorithm the pixel in the pass gets 3267 * replicated to adjacent pixels. This is why the even (0,2,4,6) 3268 * passes are skipped above - the entire expanded row is copied. 3269 */ 3270 bytes_to_copy = (1<<((6-pass)>>1)) * pixel_depth; 3271 3272 /* But don't allow this number to exceed the actual row width. */ 3273 if (bytes_to_copy > row_width) 3274 bytes_to_copy = row_width; 3275 } 3276 3277 else /* normal row; Adam7 only ever gives us one pixel to copy. */ 3278 bytes_to_copy = pixel_depth; 3279 3280 /* In Adam7 there is a constant offset between where the pixels go. */ 3281 bytes_to_jump = PNG_PASS_COL_OFFSET(pass) * pixel_depth; 3282 3283 /* And simply copy these bytes. Some optimization is possible here, 3284 * depending on the value of 'bytes_to_copy'. Special case the low 3285 * byte counts, which we know to be frequent. 3286 * 3287 * Notice that these cases all 'return' rather than 'break' - this 3288 * avoids an unnecessary test on whether to restore the last byte 3289 * below. 3290 */ 3291 switch (bytes_to_copy) 3292 { 3293 case 1: 3294 for (;;) 3295 { 3296 *dp = *sp; 3297 3298 if (row_width <= bytes_to_jump) 3299 return; 3300 3301 dp += bytes_to_jump; 3302 sp += bytes_to_jump; 3303 row_width -= bytes_to_jump; 3304 } 3305 3306 case 2: 3307 /* There is a possibility of a partial copy at the end here; this 3308 * slows the code down somewhat. 3309 */ 3310 do 3311 { 3312 dp[0] = sp[0], dp[1] = sp[1]; 3313 3314 if (row_width <= bytes_to_jump) 3315 return; 3316 3317 sp += bytes_to_jump; 3318 dp += bytes_to_jump; 3319 row_width -= bytes_to_jump; 3320 } 3321 while (row_width > 1); 3322 3323 /* And there can only be one byte left at this point: */ 3324 *dp = *sp; 3325 return; 3326 3327 case 3: 3328 /* This can only be the RGB case, so each copy is exactly one 3329 * pixel and it is not necessary to check for a partial copy. 3330 */ 3331 for(;;) 3332 { 3333 dp[0] = sp[0], dp[1] = sp[1], dp[2] = sp[2]; 3334 3335 if (row_width <= bytes_to_jump) 3336 return; 3337 3338 sp += bytes_to_jump; 3339 dp += bytes_to_jump; 3340 row_width -= bytes_to_jump; 3341 } 3342 3343 default: 3344 #if PNG_ALIGN_TYPE != PNG_ALIGN_NONE 3345 /* Check for double byte alignment and, if possible, use a 3346 * 16-bit copy. Don't attempt this for narrow images - ones that 3347 * are less than an interlace panel wide. Don't attempt it for 3348 * wide bytes_to_copy either - use the memcpy there. 3349 */ 3350 if (bytes_to_copy < 16 /*else use memcpy*/ && 3351 png_isaligned(dp, png_uint_16) && 3352 png_isaligned(sp, png_uint_16) && 3353 bytes_to_copy % (sizeof (png_uint_16)) == 0 && 3354 bytes_to_jump % (sizeof (png_uint_16)) == 0) 3355 { 3356 /* Everything is aligned for png_uint_16 copies, but try for 3357 * png_uint_32 first. 3358 */ 3359 if (png_isaligned(dp, png_uint_32) && 3360 png_isaligned(sp, png_uint_32) && 3361 bytes_to_copy % (sizeof (png_uint_32)) == 0 && 3362 bytes_to_jump % (sizeof (png_uint_32)) == 0) 3363 { 3364 png_uint_32p dp32 = png_aligncast(png_uint_32p,dp); 3365 png_const_uint_32p sp32 = png_aligncastconst( 3366 png_const_uint_32p, sp); 3367 size_t skip = (bytes_to_jump-bytes_to_copy) / 3368 (sizeof (png_uint_32)); 3369 3370 do 3371 { 3372 size_t c = bytes_to_copy; 3373 do 3374 { 3375 *dp32++ = *sp32++; 3376 c -= (sizeof (png_uint_32)); 3377 } 3378 while (c > 0); 3379 3380 if (row_width <= bytes_to_jump) 3381 return; 3382 3383 dp32 += skip; 3384 sp32 += skip; 3385 row_width -= bytes_to_jump; 3386 } 3387 while (bytes_to_copy <= row_width); 3388 3389 /* Get to here when the row_width truncates the final copy. 3390 * There will be 1-3 bytes left to copy, so don't try the 3391 * 16-bit loop below. 3392 */ 3393 dp = (png_bytep)dp32; 3394 sp = (png_const_bytep)sp32; 3395 do 3396 *dp++ = *sp++; 3397 while (--row_width > 0); 3398 return; 3399 } 3400 3401 /* Else do it in 16-bit quantities, but only if the size is 3402 * not too large. 3403 */ 3404 else 3405 { 3406 png_uint_16p dp16 = png_aligncast(png_uint_16p, dp); 3407 png_const_uint_16p sp16 = png_aligncastconst( 3408 png_const_uint_16p, sp); 3409 size_t skip = (bytes_to_jump-bytes_to_copy) / 3410 (sizeof (png_uint_16)); 3411 3412 do 3413 { 3414 size_t c = bytes_to_copy; 3415 do 3416 { 3417 *dp16++ = *sp16++; 3418 c -= (sizeof (png_uint_16)); 3419 } 3420 while (c > 0); 3421 3422 if (row_width <= bytes_to_jump) 3423 return; 3424 3425 dp16 += skip; 3426 sp16 += skip; 3427 row_width -= bytes_to_jump; 3428 } 3429 while (bytes_to_copy <= row_width); 3430 3431 /* End of row - 1 byte left, bytes_to_copy > row_width: */ 3432 dp = (png_bytep)dp16; 3433 sp = (png_const_bytep)sp16; 3434 do 3435 *dp++ = *sp++; 3436 while (--row_width > 0); 3437 return; 3438 } 3439 } 3440 #endif /* PNG_ALIGN_ code */ 3441 3442 /* The true default - use a memcpy: */ 3443 for (;;) 3444 { 3445 memcpy(dp, sp, bytes_to_copy); 3446 3447 if (row_width <= bytes_to_jump) 3448 return; 3449 3450 sp += bytes_to_jump; 3451 dp += bytes_to_jump; 3452 row_width -= bytes_to_jump; 3453 if (bytes_to_copy > row_width) 3454 bytes_to_copy = row_width; 3455 } 3456 } 3457 3458 /* NOT REACHED*/ 3459 } /* pixel_depth >= 8 */ 3460 3461 /* Here if pixel_depth < 8 to check 'end_ptr' below. */ 3462 } 3463 else 3464 #endif 3465 3466 /* If here then the switch above wasn't used so just memcpy the whole row 3467 * from the temporary row buffer (notice that this overwrites the end of the 3468 * destination row if it is a partial byte.) 3469 */ 3470 memcpy(dp, sp, PNG_ROWBYTES(pixel_depth, row_width)); 3471 3472 /* Restore the overwritten bits from the last byte if necessary. */ 3473 if (end_ptr != NULL) 3474 *end_ptr = (png_byte)((end_byte & end_mask) | (*end_ptr & ~end_mask)); 3475 } 3476 3477 #ifdef PNG_READ_INTERLACING_SUPPORTED 3478 void /* PRIVATE */ 3479 png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass, 3480 png_uint_32 transformations /* Because these may affect the byte layout */) 3481 { 3482 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ 3483 /* Offset to next interlace block */ 3484 static PNG_CONST int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1}; 3485 3486 png_debug(1, "in png_do_read_interlace"); 3487 if (row != NULL && row_info != NULL) 3488 { 3489 png_uint_32 final_width; 3490 3491 final_width = row_info->width * png_pass_inc[pass]; 3492 3493 switch (row_info->pixel_depth) 3494 { 3495 case 1: 3496 { 3497 png_bytep sp = row + (png_size_t)((row_info->width - 1) >> 3); 3498 png_bytep dp = row + (png_size_t)((final_width - 1) >> 3); 3499 int sshift, dshift; 3500 int s_start, s_end, s_inc; 3501 int jstop = png_pass_inc[pass]; 3502 png_byte v; 3503 png_uint_32 i; 3504 int j; 3505 3506 #ifdef PNG_READ_PACKSWAP_SUPPORTED 3507 if (transformations & PNG_PACKSWAP) 3508 { 3509 sshift = (int)((row_info->width + 7) & 0x07); 3510 dshift = (int)((final_width + 7) & 0x07); 3511 s_start = 7; 3512 s_end = 0; 3513 s_inc = -1; 3514 } 3515 3516 else 3517 #endif 3518 { 3519 sshift = 7 - (int)((row_info->width + 7) & 0x07); 3520 dshift = 7 - (int)((final_width + 7) & 0x07); 3521 s_start = 0; 3522 s_end = 7; 3523 s_inc = 1; 3524 } 3525 3526 for (i = 0; i < row_info->width; i++) 3527 { 3528 v = (png_byte)((*sp >> sshift) & 0x01); 3529 for (j = 0; j < jstop; j++) 3530 { 3531 unsigned int tmp = *dp & (0x7f7f >> (7 - dshift)); 3532 tmp |= v << dshift; 3533 *dp = (png_byte)(tmp & 0xff); 3534 3535 if (dshift == s_end) 3536 { 3537 dshift = s_start; 3538 dp--; 3539 } 3540 3541 else 3542 dshift += s_inc; 3543 } 3544 3545 if (sshift == s_end) 3546 { 3547 sshift = s_start; 3548 sp--; 3549 } 3550 3551 else 3552 sshift += s_inc; 3553 } 3554 break; 3555 } 3556 3557 case 2: 3558 { 3559 png_bytep sp = row + (png_uint_32)((row_info->width - 1) >> 2); 3560 png_bytep dp = row + (png_uint_32)((final_width - 1) >> 2); 3561 int sshift, dshift; 3562 int s_start, s_end, s_inc; 3563 int jstop = png_pass_inc[pass]; 3564 png_uint_32 i; 3565 3566 #ifdef PNG_READ_PACKSWAP_SUPPORTED 3567 if (transformations & PNG_PACKSWAP) 3568 { 3569 sshift = (int)(((row_info->width + 3) & 0x03) << 1); 3570 dshift = (int)(((final_width + 3) & 0x03) << 1); 3571 s_start = 6; 3572 s_end = 0; 3573 s_inc = -2; 3574 } 3575 3576 else 3577 #endif 3578 { 3579 sshift = (int)((3 - ((row_info->width + 3) & 0x03)) << 1); 3580 dshift = (int)((3 - ((final_width + 3) & 0x03)) << 1); 3581 s_start = 0; 3582 s_end = 6; 3583 s_inc = 2; 3584 } 3585 3586 for (i = 0; i < row_info->width; i++) 3587 { 3588 png_byte v; 3589 int j; 3590 3591 v = (png_byte)((*sp >> sshift) & 0x03); 3592 for (j = 0; j < jstop; j++) 3593 { 3594 unsigned int tmp = *dp & (0x3f3f >> (6 - dshift)); 3595 tmp |= v << dshift; 3596 *dp = (png_byte)(tmp & 0xff); 3597 3598 if (dshift == s_end) 3599 { 3600 dshift = s_start; 3601 dp--; 3602 } 3603 3604 else 3605 dshift += s_inc; 3606 } 3607 3608 if (sshift == s_end) 3609 { 3610 sshift = s_start; 3611 sp--; 3612 } 3613 3614 else 3615 sshift += s_inc; 3616 } 3617 break; 3618 } 3619 3620 case 4: 3621 { 3622 png_bytep sp = row + (png_size_t)((row_info->width - 1) >> 1); 3623 png_bytep dp = row + (png_size_t)((final_width - 1) >> 1); 3624 int sshift, dshift; 3625 int s_start, s_end, s_inc; 3626 png_uint_32 i; 3627 int jstop = png_pass_inc[pass]; 3628 3629 #ifdef PNG_READ_PACKSWAP_SUPPORTED 3630 if (transformations & PNG_PACKSWAP) 3631 { 3632 sshift = (int)(((row_info->width + 1) & 0x01) << 2); 3633 dshift = (int)(((final_width + 1) & 0x01) << 2); 3634 s_start = 4; 3635 s_end = 0; 3636 s_inc = -4; 3637 } 3638 3639 else 3640 #endif 3641 { 3642 sshift = (int)((1 - ((row_info->width + 1) & 0x01)) << 2); 3643 dshift = (int)((1 - ((final_width + 1) & 0x01)) << 2); 3644 s_start = 0; 3645 s_end = 4; 3646 s_inc = 4; 3647 } 3648 3649 for (i = 0; i < row_info->width; i++) 3650 { 3651 png_byte v = (png_byte)((*sp >> sshift) & 0x0f); 3652 int j; 3653 3654 for (j = 0; j < jstop; j++) 3655 { 3656 unsigned int tmp = *dp & (0xf0f >> (4 - dshift)); 3657 tmp |= v << dshift; 3658 *dp = (png_byte)(tmp & 0xff); 3659 3660 if (dshift == s_end) 3661 { 3662 dshift = s_start; 3663 dp--; 3664 } 3665 3666 else 3667 dshift += s_inc; 3668 } 3669 3670 if (sshift == s_end) 3671 { 3672 sshift = s_start; 3673 sp--; 3674 } 3675 3676 else 3677 sshift += s_inc; 3678 } 3679 break; 3680 } 3681 3682 default: 3683 { 3684 png_size_t pixel_bytes = (row_info->pixel_depth >> 3); 3685 3686 png_bytep sp = row + (png_size_t)(row_info->width - 1) 3687 * pixel_bytes; 3688 3689 png_bytep dp = row + (png_size_t)(final_width - 1) * pixel_bytes; 3690 3691 int jstop = png_pass_inc[pass]; 3692 png_uint_32 i; 3693 3694 for (i = 0; i < row_info->width; i++) 3695 { 3696 png_byte v[8]; /* SAFE; pixel_depth does not exceed 64 */ 3697 int j; 3698 3699 memcpy(v, sp, pixel_bytes); 3700 3701 for (j = 0; j < jstop; j++) 3702 { 3703 memcpy(dp, v, pixel_bytes); 3704 dp -= pixel_bytes; 3705 } 3706 3707 sp -= pixel_bytes; 3708 } 3709 break; 3710 } 3711 } 3712 3713 row_info->width = final_width; 3714 row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, final_width); 3715 } 3716 #ifndef PNG_READ_PACKSWAP_SUPPORTED 3717 PNG_UNUSED(transformations) /* Silence compiler warning */ 3718 #endif 3719 } 3720 #endif /* PNG_READ_INTERLACING_SUPPORTED */ 3721 3722 static void 3723 png_read_filter_row_sub(png_row_infop row_info, png_bytep row, 3724 png_const_bytep prev_row) 3725 { 3726 png_size_t i; 3727 png_size_t istop = row_info->rowbytes; 3728 unsigned int bpp = (row_info->pixel_depth + 7) >> 3; 3729 png_bytep rp = row + bpp; 3730 3731 PNG_UNUSED(prev_row) 3732 3733 for (i = bpp; i < istop; i++) 3734 { 3735 *rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 0xff); 3736 rp++; 3737 } 3738 } 3739 3740 static void 3741 png_read_filter_row_up(png_row_infop row_info, png_bytep row, 3742 png_const_bytep prev_row) 3743 { 3744 png_size_t i; 3745 png_size_t istop = row_info->rowbytes; 3746 png_bytep rp = row; 3747 png_const_bytep pp = prev_row; 3748 3749 for (i = 0; i < istop; i++) 3750 { 3751 *rp = (png_byte)(((int)(*rp) + (int)(*pp++)) & 0xff); 3752 rp++; 3753 } 3754 } 3755 3756 static void 3757 png_read_filter_row_avg(png_row_infop row_info, png_bytep row, 3758 png_const_bytep prev_row) 3759 { 3760 png_size_t i; 3761 png_bytep rp = row; 3762 png_const_bytep pp = prev_row; 3763 unsigned int bpp = (row_info->pixel_depth + 7) >> 3; 3764 png_size_t istop = row_info->rowbytes - bpp; 3765 3766 for (i = 0; i < bpp; i++) 3767 { 3768 *rp = (png_byte)(((int)(*rp) + 3769 ((int)(*pp++) / 2 )) & 0xff); 3770 3771 rp++; 3772 } 3773 3774 for (i = 0; i < istop; i++) 3775 { 3776 *rp = (png_byte)(((int)(*rp) + 3777 (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff); 3778 3779 rp++; 3780 } 3781 } 3782 3783 static void 3784 png_read_filter_row_paeth_1byte_pixel(png_row_infop row_info, png_bytep row, 3785 png_const_bytep prev_row) 3786 { 3787 png_bytep rp_end = row + row_info->rowbytes; 3788 int a, c; 3789 3790 /* First pixel/byte */ 3791 c = *prev_row++; 3792 a = *row + c; 3793 *row++ = (png_byte)a; 3794 3795 /* Remainder */ 3796 while (row < rp_end) 3797 { 3798 int b, pa, pb, pc, p; 3799 3800 a &= 0xff; /* From previous iteration or start */ 3801 b = *prev_row++; 3802 3803 p = b - c; 3804 pc = a - c; 3805 3806 # ifdef PNG_USE_ABS 3807 pa = abs(p); 3808 pb = abs(pc); 3809 pc = abs(p + pc); 3810 # else 3811 pa = p < 0 ? -p : p; 3812 pb = pc < 0 ? -pc : pc; 3813 pc = (p + pc) < 0 ? -(p + pc) : p + pc; 3814 # endif 3815 3816 /* Find the best predictor, the least of pa, pb, pc favoring the earlier 3817 * ones in the case of a tie. 3818 */ 3819 if (pb < pa) pa = pb, a = b; 3820 if (pc < pa) a = c; 3821 3822 /* Calculate the current pixel in a, and move the previous row pixel to c 3823 * for the next time round the loop 3824 */ 3825 c = b; 3826 a += *row; 3827 *row++ = (png_byte)a; 3828 } 3829 } 3830 3831 static void 3832 png_read_filter_row_paeth_multibyte_pixel(png_row_infop row_info, png_bytep row, 3833 png_const_bytep prev_row) 3834 { 3835 int bpp = (row_info->pixel_depth + 7) >> 3; 3836 png_bytep rp_end = row + bpp; 3837 3838 /* Process the first pixel in the row completely (this is the same as 'up' 3839 * because there is only one candidate predictor for the first row). 3840 */ 3841 while (row < rp_end) 3842 { 3843 int a = *row + *prev_row++; 3844 *row++ = (png_byte)a; 3845 } 3846 3847 /* Remainder */ 3848 rp_end += row_info->rowbytes - bpp; 3849 3850 while (row < rp_end) 3851 { 3852 int a, b, c, pa, pb, pc, p; 3853 3854 c = *(prev_row - bpp); 3855 a = *(row - bpp); 3856 b = *prev_row++; 3857 3858 p = b - c; 3859 pc = a - c; 3860 3861 # ifdef PNG_USE_ABS 3862 pa = abs(p); 3863 pb = abs(pc); 3864 pc = abs(p + pc); 3865 # else 3866 pa = p < 0 ? -p : p; 3867 pb = pc < 0 ? -pc : pc; 3868 pc = (p + pc) < 0 ? -(p + pc) : p + pc; 3869 # endif 3870 3871 if (pb < pa) pa = pb, a = b; 3872 if (pc < pa) a = c; 3873 3874 c = b; 3875 a += *row; 3876 *row++ = (png_byte)a; 3877 } 3878 } 3879 3880 static void 3881 png_init_filter_functions(png_structrp pp) 3882 /* This function is called once for every PNG image to set the 3883 * implementations required to reverse the filtering of PNG rows. Reversing 3884 * the filter is the first transformation performed on the row data. It is 3885 * performed in place, therefore an implementation can be selected based on 3886 * the image pixel format. If the implementation depends on image width then 3887 * take care to ensure that it works correctly if the image is interlaced - 3888 * interlacing causes the actual row width to vary. 3889 */ 3890 { 3891 unsigned int bpp = (pp->pixel_depth + 7) >> 3; 3892 3893 pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub; 3894 pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up; 3895 pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg; 3896 if (bpp == 1) 3897 pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = 3898 png_read_filter_row_paeth_1byte_pixel; 3899 else 3900 pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = 3901 png_read_filter_row_paeth_multibyte_pixel; 3902 3903 #ifdef PNG_FILTER_OPTIMIZATIONS 3904 /* To use this define PNG_FILTER_OPTIMIZATIONS as the name of a function to 3905 * call to install hardware optimizations for the above functions; simply 3906 * replace whatever elements of the pp->read_filter[] array with a hardware 3907 * specific (or, for that matter, generic) optimization. 3908 * 3909 * To see an example of this examine what configure.ac does when 3910 * --enable-arm-neon is specified on the command line. 3911 */ 3912 PNG_FILTER_OPTIMIZATIONS(pp, bpp); 3913 #endif 3914 } 3915 3916 void /* PRIVATE */ 3917 png_read_filter_row(png_structrp pp, png_row_infop row_info, png_bytep row, 3918 png_const_bytep prev_row, int filter) 3919 { 3920 /* OPTIMIZATION: DO NOT MODIFY THIS FUNCTION, instead #define 3921 * PNG_FILTER_OPTIMIZATIONS to a function that overrides the generic 3922 * implementations. See png_init_filter_functions above. 3923 */ 3924 if (pp->read_filter[0] == NULL) 3925 png_init_filter_functions(pp); 3926 if (filter > PNG_FILTER_VALUE_NONE && filter < PNG_FILTER_VALUE_LAST) 3927 pp->read_filter[filter-1](row_info, row, prev_row); 3928 } 3929 3930 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED 3931 void /* PRIVATE */ 3932 png_read_IDAT_data(png_structrp png_ptr, png_bytep output, 3933 png_alloc_size_t avail_out) 3934 { 3935 /* Loop reading IDATs and decompressing the result into output[avail_out] */ 3936 png_ptr->zstream.next_out = output; 3937 png_ptr->zstream.avail_out = 0; /* safety: set below */ 3938 3939 if (output == NULL) 3940 avail_out = 0; 3941 3942 do 3943 { 3944 int ret; 3945 png_byte tmpbuf[PNG_INFLATE_BUF_SIZE]; 3946 3947 if (png_ptr->zstream.avail_in == 0) 3948 { 3949 uInt avail_in; 3950 png_bytep buffer; 3951 3952 while (png_ptr->idat_size == 0) 3953 { 3954 png_crc_finish(png_ptr, 0); 3955 3956 png_ptr->idat_size = png_read_chunk_header(png_ptr); 3957 /* This is an error even in the 'check' case because the code just 3958 * consumed a non-IDAT header. 3959 */ 3960 if (png_ptr->chunk_name != png_IDAT) 3961 png_error(png_ptr, "Not enough image data"); 3962 } 3963 3964 avail_in = png_ptr->IDAT_read_size; 3965 3966 if (avail_in > png_ptr->idat_size) 3967 avail_in = (uInt)png_ptr->idat_size; 3968 3969 /* A PNG with a gradually increasing IDAT size will defeat this attempt 3970 * to minimize memory usage by causing lots of re-allocs, but 3971 * realistically doing IDAT_read_size re-allocs is not likely to be a 3972 * big problem. 3973 */ 3974 buffer = png_read_buffer(png_ptr, avail_in, 0/*error*/); 3975 3976 png_crc_read(png_ptr, buffer, avail_in); 3977 png_ptr->idat_size -= avail_in; 3978 3979 png_ptr->zstream.next_in = buffer; 3980 png_ptr->zstream.avail_in = avail_in; 3981 } 3982 3983 /* And set up the output side. */ 3984 if (output != NULL) /* standard read */ 3985 { 3986 uInt out = ZLIB_IO_MAX; 3987 3988 if (out > avail_out) 3989 out = (uInt)avail_out; 3990 3991 avail_out -= out; 3992 png_ptr->zstream.avail_out = out; 3993 } 3994 3995 else /* after last row, checking for end */ 3996 { 3997 png_ptr->zstream.next_out = tmpbuf; 3998 png_ptr->zstream.avail_out = (sizeof tmpbuf); 3999 } 4000 4001 /* Use NO_FLUSH; this gives zlib the maximum opportunity to optimize the 4002 * process. If the LZ stream is truncated the sequential reader will 4003 * terminally damage the stream, above, by reading the chunk header of the 4004 * following chunk (it then exits with png_error). 4005 * 4006 * TODO: deal more elegantly with truncated IDAT lists. 4007 */ 4008 ret = inflate(&png_ptr->zstream, Z_NO_FLUSH); 4009 4010 /* Take the unconsumed output back. */ 4011 if (output != NULL) 4012 avail_out += png_ptr->zstream.avail_out; 4013 4014 else /* avail_out counts the extra bytes */ 4015 avail_out += (sizeof tmpbuf) - png_ptr->zstream.avail_out; 4016 4017 png_ptr->zstream.avail_out = 0; 4018 4019 if (ret == Z_STREAM_END) 4020 { 4021 /* Do this for safety; we won't read any more into this row. */ 4022 png_ptr->zstream.next_out = NULL; 4023 4024 png_ptr->mode |= PNG_AFTER_IDAT; 4025 png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED; 4026 4027 if (png_ptr->zstream.avail_in > 0 || png_ptr->idat_size > 0) 4028 png_chunk_benign_error(png_ptr, "Extra compressed data"); 4029 break; 4030 } 4031 4032 if (ret != Z_OK) 4033 { 4034 png_zstream_error(png_ptr, ret); 4035 4036 if (output != NULL) 4037 png_chunk_error(png_ptr, png_ptr->zstream.msg); 4038 4039 else /* checking */ 4040 { 4041 png_chunk_benign_error(png_ptr, png_ptr->zstream.msg); 4042 return; 4043 } 4044 } 4045 } while (avail_out > 0); 4046 4047 if (avail_out > 0) 4048 { 4049 /* The stream ended before the image; this is the same as too few IDATs so 4050 * should be handled the same way. 4051 */ 4052 if (output != NULL) 4053 png_error(png_ptr, "Not enough image data"); 4054 4055 else /* the deflate stream contained extra data */ 4056 png_chunk_benign_error(png_ptr, "Too much image data"); 4057 } 4058 } 4059 4060 void /* PRIVATE */ 4061 png_read_finish_IDAT(png_structrp png_ptr) 4062 { 4063 /* We don't need any more data and the stream should have ended, however the 4064 * LZ end code may actually not have been processed. In this case we must 4065 * read it otherwise stray unread IDAT data or, more likely, an IDAT chunk 4066 * may still remain to be consumed. 4067 */ 4068 if (!(png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED)) 4069 { 4070 /* The NULL causes png_read_IDAT_data to swallow any remaining bytes in 4071 * the compressed stream, but the stream may be damaged too, so even after 4072 * this call we may need to terminate the zstream ownership. 4073 */ 4074 png_read_IDAT_data(png_ptr, NULL, 0); 4075 png_ptr->zstream.next_out = NULL; /* safety */ 4076 4077 /* Now clear everything out for safety; the following may not have been 4078 * done. 4079 */ 4080 if (!(png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED)) 4081 { 4082 png_ptr->mode |= PNG_AFTER_IDAT; 4083 png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED; 4084 } 4085 } 4086 4087 /* If the zstream has not been released do it now *and* terminate the reading 4088 * of the final IDAT chunk. 4089 */ 4090 if (png_ptr->zowner == png_IDAT) 4091 { 4092 /* Always do this; the pointers otherwise point into the read buffer. */ 4093 png_ptr->zstream.next_in = NULL; 4094 png_ptr->zstream.avail_in = 0; 4095 4096 /* Now we no longer own the zstream. */ 4097 png_ptr->zowner = 0; 4098 4099 /* The slightly weird semantics of the sequential IDAT reading is that we 4100 * are always in or at the end of an IDAT chunk, so we always need to do a 4101 * crc_finish here. If idat_size is non-zero we also need to read the 4102 * spurious bytes at the end of the chunk now. 4103 */ 4104 (void)png_crc_finish(png_ptr, png_ptr->idat_size); 4105 } 4106 } 4107 4108 void /* PRIVATE */ 4109 png_read_finish_row(png_structrp png_ptr) 4110 { 4111 #ifdef PNG_READ_INTERLACING_SUPPORTED 4112 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ 4113 4114 /* Start of interlace block */ 4115 static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0}; 4116 4117 /* Offset to next interlace block */ 4118 static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1}; 4119 4120 /* Start of interlace block in the y direction */ 4121 static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1}; 4122 4123 /* Offset to next interlace block in the y direction */ 4124 static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2}; 4125 #endif /* PNG_READ_INTERLACING_SUPPORTED */ 4126 4127 png_debug(1, "in png_read_finish_row"); 4128 png_ptr->row_number++; 4129 if (png_ptr->row_number < png_ptr->num_rows) 4130 return; 4131 4132 #ifdef PNG_READ_INTERLACING_SUPPORTED 4133 if (png_ptr->interlaced) 4134 { 4135 png_ptr->row_number = 0; 4136 4137 /* TO DO: don't do this if prev_row isn't needed (requires 4138 * read-ahead of the next row's filter byte. 4139 */ 4140 memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1); 4141 4142 do 4143 { 4144 png_ptr->pass++; 4145 4146 if (png_ptr->pass >= 7) 4147 break; 4148 4149 png_ptr->iwidth = (png_ptr->width + 4150 png_pass_inc[png_ptr->pass] - 1 - 4151 png_pass_start[png_ptr->pass]) / 4152 png_pass_inc[png_ptr->pass]; 4153 4154 if (!(png_ptr->transformations & PNG_INTERLACE)) 4155 { 4156 png_ptr->num_rows = (png_ptr->height + 4157 png_pass_yinc[png_ptr->pass] - 1 - 4158 png_pass_ystart[png_ptr->pass]) / 4159 png_pass_yinc[png_ptr->pass]; 4160 } 4161 4162 else /* if (png_ptr->transformations & PNG_INTERLACE) */ 4163 break; /* libpng deinterlacing sees every row */ 4164 4165 } while (png_ptr->num_rows == 0 || png_ptr->iwidth == 0); 4166 4167 if (png_ptr->pass < 7) 4168 return; 4169 } 4170 #endif /* PNG_READ_INTERLACING_SUPPORTED */ 4171 4172 /* Here after at the end of the last row of the last pass. */ 4173 png_read_finish_IDAT(png_ptr); 4174 } 4175 #endif /* PNG_SEQUENTIAL_READ_SUPPORTED */ 4176 4177 void /* PRIVATE */ 4178 png_read_start_row(png_structrp png_ptr) 4179 { 4180 #ifdef PNG_READ_INTERLACING_SUPPORTED 4181 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ 4182 4183 /* Start of interlace block */ 4184 static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0}; 4185 4186 /* Offset to next interlace block */ 4187 static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1}; 4188 4189 /* Start of interlace block in the y direction */ 4190 static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1}; 4191 4192 /* Offset to next interlace block in the y direction */ 4193 static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2}; 4194 #endif 4195 4196 int max_pixel_depth; 4197 png_size_t row_bytes; 4198 4199 png_debug(1, "in png_read_start_row"); 4200 4201 #ifdef PNG_READ_TRANSFORMS_SUPPORTED 4202 png_init_read_transformations(png_ptr); 4203 #endif 4204 #ifdef PNG_READ_INTERLACING_SUPPORTED 4205 if (png_ptr->interlaced) 4206 { 4207 if (!(png_ptr->transformations & PNG_INTERLACE)) 4208 png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 - 4209 png_pass_ystart[0]) / png_pass_yinc[0]; 4210 4211 else 4212 png_ptr->num_rows = png_ptr->height; 4213 4214 png_ptr->iwidth = (png_ptr->width + 4215 png_pass_inc[png_ptr->pass] - 1 - 4216 png_pass_start[png_ptr->pass]) / 4217 png_pass_inc[png_ptr->pass]; 4218 } 4219 4220 else 4221 #endif /* PNG_READ_INTERLACING_SUPPORTED */ 4222 { 4223 png_ptr->num_rows = png_ptr->height; 4224 png_ptr->iwidth = png_ptr->width; 4225 } 4226 4227 max_pixel_depth = png_ptr->pixel_depth; 4228 4229 /* WARNING: * png_read_transform_info (pngrtran.c) performs a simpliar set of 4230 * calculations to calculate the final pixel depth, then 4231 * png_do_read_transforms actually does the transforms. This means that the 4232 * code which effectively calculates this value is actually repeated in three 4233 * separate places. They must all match. Innocent changes to the order of 4234 * transformations can and will break libpng in a way that causes memory 4235 * overwrites. 4236 * 4237 * TODO: fix this. 4238 */ 4239 #ifdef PNG_READ_PACK_SUPPORTED 4240 if ((png_ptr->transformations & PNG_PACK) && png_ptr->bit_depth < 8) 4241 max_pixel_depth = 8; 4242 #endif 4243 4244 #ifdef PNG_READ_EXPAND_SUPPORTED 4245 if (png_ptr->transformations & PNG_EXPAND) 4246 { 4247 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) 4248 { 4249 if (png_ptr->num_trans) 4250 max_pixel_depth = 32; 4251 4252 else 4253 max_pixel_depth = 24; 4254 } 4255 4256 else if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY) 4257 { 4258 if (max_pixel_depth < 8) 4259 max_pixel_depth = 8; 4260 4261 if (png_ptr->num_trans) 4262 max_pixel_depth *= 2; 4263 } 4264 4265 else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB) 4266 { 4267 if (png_ptr->num_trans) 4268 { 4269 max_pixel_depth *= 4; 4270 max_pixel_depth /= 3; 4271 } 4272 } 4273 } 4274 #endif 4275 4276 #ifdef PNG_READ_EXPAND_16_SUPPORTED 4277 if (png_ptr->transformations & PNG_EXPAND_16) 4278 { 4279 # ifdef PNG_READ_EXPAND_SUPPORTED 4280 /* In fact it is an error if it isn't supported, but checking is 4281 * the safe way. 4282 */ 4283 if (png_ptr->transformations & PNG_EXPAND) 4284 { 4285 if (png_ptr->bit_depth < 16) 4286 max_pixel_depth *= 2; 4287 } 4288 else 4289 # endif 4290 png_ptr->transformations &= ~PNG_EXPAND_16; 4291 } 4292 #endif 4293 4294 #ifdef PNG_READ_FILLER_SUPPORTED 4295 if (png_ptr->transformations & (PNG_FILLER)) 4296 { 4297 if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY) 4298 { 4299 if (max_pixel_depth <= 8) 4300 max_pixel_depth = 16; 4301 4302 else 4303 max_pixel_depth = 32; 4304 } 4305 4306 else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB || 4307 png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) 4308 { 4309 if (max_pixel_depth <= 32) 4310 max_pixel_depth = 32; 4311 4312 else 4313 max_pixel_depth = 64; 4314 } 4315 } 4316 #endif 4317 4318 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED 4319 if (png_ptr->transformations & PNG_GRAY_TO_RGB) 4320 { 4321 if ( 4322 #ifdef PNG_READ_EXPAND_SUPPORTED 4323 (png_ptr->num_trans && (png_ptr->transformations & PNG_EXPAND)) || 4324 #endif 4325 #ifdef PNG_READ_FILLER_SUPPORTED 4326 (png_ptr->transformations & (PNG_FILLER)) || 4327 #endif 4328 png_ptr->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) 4329 { 4330 if (max_pixel_depth <= 16) 4331 max_pixel_depth = 32; 4332 4333 else 4334 max_pixel_depth = 64; 4335 } 4336 4337 else 4338 { 4339 if (max_pixel_depth <= 8) 4340 { 4341 if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA) 4342 max_pixel_depth = 32; 4343 4344 else 4345 max_pixel_depth = 24; 4346 } 4347 4348 else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA) 4349 max_pixel_depth = 64; 4350 4351 else 4352 max_pixel_depth = 48; 4353 } 4354 } 4355 #endif 4356 4357 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) && \ 4358 defined(PNG_USER_TRANSFORM_PTR_SUPPORTED) 4359 if (png_ptr->transformations & PNG_USER_TRANSFORM) 4360 { 4361 int user_pixel_depth = png_ptr->user_transform_depth * 4362 png_ptr->user_transform_channels; 4363 4364 if (user_pixel_depth > max_pixel_depth) 4365 max_pixel_depth = user_pixel_depth; 4366 } 4367 #endif 4368 4369 /* This value is stored in png_struct and double checked in the row read 4370 * code. 4371 */ 4372 png_ptr->maximum_pixel_depth = (png_byte)max_pixel_depth; 4373 png_ptr->transformed_pixel_depth = 0; /* calculated on demand */ 4374 4375 /* Align the width on the next larger 8 pixels. Mainly used 4376 * for interlacing 4377 */ 4378 row_bytes = ((png_ptr->width + 7) & ~((png_uint_32)7)); 4379 /* Calculate the maximum bytes needed, adding a byte and a pixel 4380 * for safety's sake 4381 */ 4382 row_bytes = PNG_ROWBYTES(max_pixel_depth, row_bytes) + 4383 1 + ((max_pixel_depth + 7) >> 3); 4384 4385 #ifdef PNG_MAX_MALLOC_64K 4386 if (row_bytes > (png_uint_32)65536L) 4387 png_error(png_ptr, "This image requires a row greater than 64KB"); 4388 #endif 4389 4390 if (row_bytes + 48 > png_ptr->old_big_row_buf_size) 4391 { 4392 png_free(png_ptr, png_ptr->big_row_buf); 4393 png_free(png_ptr, png_ptr->big_prev_row); 4394 4395 if (png_ptr->interlaced) 4396 png_ptr->big_row_buf = (png_bytep)png_calloc(png_ptr, 4397 row_bytes + 48); 4398 4399 else 4400 png_ptr->big_row_buf = (png_bytep)png_malloc(png_ptr, row_bytes + 48); 4401 4402 png_ptr->big_prev_row = (png_bytep)png_malloc(png_ptr, row_bytes + 48); 4403 4404 #ifdef PNG_ALIGNED_MEMORY_SUPPORTED 4405 /* Use 16-byte aligned memory for row_buf with at least 16 bytes 4406 * of padding before and after row_buf; treat prev_row similarly. 4407 * NOTE: the alignment is to the start of the pixels, one beyond the start 4408 * of the buffer, because of the filter byte. Prior to libpng 1.5.6 this 4409 * was incorrect; the filter byte was aligned, which had the exact 4410 * opposite effect of that intended. 4411 */ 4412 { 4413 png_bytep temp = png_ptr->big_row_buf + 32; 4414 int extra = (int)((temp - (png_bytep)0) & 0x0f); 4415 png_ptr->row_buf = temp - extra - 1/*filter byte*/; 4416 4417 temp = png_ptr->big_prev_row + 32; 4418 extra = (int)((temp - (png_bytep)0) & 0x0f); 4419 png_ptr->prev_row = temp - extra - 1/*filter byte*/; 4420 } 4421 4422 #else 4423 /* Use 31 bytes of padding before and 17 bytes after row_buf. */ 4424 png_ptr->row_buf = png_ptr->big_row_buf + 31; 4425 png_ptr->prev_row = png_ptr->big_prev_row + 31; 4426 #endif 4427 png_ptr->old_big_row_buf_size = row_bytes + 48; 4428 } 4429 4430 #ifdef PNG_MAX_MALLOC_64K 4431 if (png_ptr->rowbytes > 65535) 4432 png_error(png_ptr, "This image requires a row greater than 64KB"); 4433 4434 #endif 4435 if (png_ptr->rowbytes > (PNG_SIZE_MAX - 1)) 4436 png_error(png_ptr, "Row has too many bytes to allocate in memory"); 4437 4438 memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1); 4439 4440 png_debug1(3, "width = %u,", png_ptr->width); 4441 png_debug1(3, "height = %u,", png_ptr->height); 4442 png_debug1(3, "iwidth = %u,", png_ptr->iwidth); 4443 png_debug1(3, "num_rows = %u,", png_ptr->num_rows); 4444 png_debug1(3, "rowbytes = %lu,", (unsigned long)png_ptr->rowbytes); 4445 png_debug1(3, "irowbytes = %lu", 4446 (unsigned long)PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->iwidth) + 1); 4447 4448 /* The sequential reader needs a buffer for IDAT, but the progressive reader 4449 * does not, so free the read buffer now regardless; the sequential reader 4450 * reallocates it on demand. 4451 */ 4452 if (png_ptr->read_buffer) 4453 { 4454 png_bytep buffer = png_ptr->read_buffer; 4455 4456 png_ptr->read_buffer_size = 0; 4457 png_ptr->read_buffer = NULL; 4458 png_free(png_ptr, buffer); 4459 } 4460 4461 /* Finally claim the zstream for the inflate of the IDAT data, use the bits 4462 * value from the stream (note that this will result in a fatal error if the 4463 * IDAT stream has a bogus deflate header window_bits value, but this should 4464 * not be happening any longer!) 4465 */ 4466 if (png_inflate_claim(png_ptr, png_IDAT) != Z_OK) 4467 png_error(png_ptr, png_ptr->zstream.msg); 4468 4469 png_ptr->flags |= PNG_FLAG_ROW_INIT; 4470 } 4471 #endif /* PNG_READ_SUPPORTED */ 4472