1 /* 2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 3 * 4 * This code is free software; you can redistribute it and/or modify it 5 * under the terms of the GNU General Public License version 2 only, as 6 * published by the Free Software Foundation. Oracle designates this 7 * particular file as subject to the "Classpath" exception as provided 8 * by Oracle in the LICENSE file that accompanied this code. 9 * 10 * This code is distributed in the hope that it will be useful, but WITHOUT 11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 13 * version 2 for more details (a copy is included in the LICENSE file that 14 * accompanied this code). 15 * 16 * You should have received a copy of the GNU General Public License version 17 * 2 along with this work; if not, write to the Free Software Foundation, 18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 19 * 20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 21 * or visit www.oracle.com if you need additional information or have any 22 * questions. 23 */ 24 25 /* pngrutil.c - utilities to read a PNG file 26 * 27 * This file is available under and governed by the GNU General Public 28 * License version 2 only, as published by the Free Software Foundation. 29 * However, the following notice accompanied the original version of this 30 * file and, per its terms, should not be removed: 31 * 32 * Last changed in libpng 1.6.35 [July 15, 2018] 33 * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson 34 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) 35 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) 36 * 37 * This code is released under the libpng license. 38 * For conditions of distribution and use, see the disclaimer 39 * and license in png.h 40 * 41 * This file contains routines that are only called from within 42 * libpng itself during the course of reading an image. 43 */ 44 45 #include "pngpriv.h" 46 47 #ifdef PNG_READ_SUPPORTED 48 49 png_uint_32 PNGAPI 50 png_get_uint_31(png_const_structrp png_ptr, png_const_bytep buf) 51 { 52 png_uint_32 uval = png_get_uint_32(buf); 53 54 if (uval > PNG_UINT_31_MAX) 55 png_error(png_ptr, "PNG unsigned integer out of range"); 56 57 return (uval); 58 } 59 60 #if defined(PNG_READ_gAMA_SUPPORTED) || defined(PNG_READ_cHRM_SUPPORTED) 61 /* The following is a variation on the above for use with the fixed 62 * point values used for gAMA and cHRM. Instead of png_error it 63 * issues a warning and returns (-1) - an invalid value because both 64 * gAMA and cHRM use *unsigned* integers for fixed point values. 65 */ 66 #define PNG_FIXED_ERROR (-1) 67 68 static png_fixed_point /* PRIVATE */ 69 png_get_fixed_point(png_structrp png_ptr, png_const_bytep buf) 70 { 71 png_uint_32 uval = png_get_uint_32(buf); 72 73 if (uval <= PNG_UINT_31_MAX) 74 return (png_fixed_point)uval; /* known to be in range */ 75 76 /* The caller can turn off the warning by passing NULL. */ 77 if (png_ptr != NULL) 78 png_warning(png_ptr, "PNG fixed point integer out of range"); 79 80 return PNG_FIXED_ERROR; 81 } 82 #endif 83 84 #ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED 85 /* NOTE: the read macros will obscure these definitions, so that if 86 * PNG_USE_READ_MACROS is set the library will not use them internally, 87 * but the APIs will still be available externally. 88 * 89 * The parentheses around "PNGAPI function_name" in the following three 90 * functions are necessary because they allow the macros to co-exist with 91 * these (unused but exported) functions. 92 */ 93 94 /* Grab an unsigned 32-bit integer from a buffer in big-endian format. */ 95 png_uint_32 (PNGAPI 96 png_get_uint_32)(png_const_bytep buf) 97 { 98 png_uint_32 uval = 99 ((png_uint_32)(*(buf )) << 24) + 100 ((png_uint_32)(*(buf + 1)) << 16) + 101 ((png_uint_32)(*(buf + 2)) << 8) + 102 ((png_uint_32)(*(buf + 3)) ) ; 103 104 return uval; 105 } 106 107 /* Grab a signed 32-bit integer from a buffer in big-endian format. The 108 * data is stored in the PNG file in two's complement format and there 109 * is no guarantee that a 'png_int_32' is exactly 32 bits, therefore 110 * the following code does a two's complement to native conversion. 111 */ 112 png_int_32 (PNGAPI 113 png_get_int_32)(png_const_bytep buf) 114 { 115 png_uint_32 uval = png_get_uint_32(buf); 116 if ((uval & 0x80000000) == 0) /* non-negative */ 117 return (png_int_32)uval; 118 119 uval = (uval ^ 0xffffffff) + 1; /* 2's complement: -x = ~x+1 */ 120 if ((uval & 0x80000000) == 0) /* no overflow */ 121 return -(png_int_32)uval; 122 /* The following has to be safe; this function only gets called on PNG data 123 * and if we get here that data is invalid. 0 is the most safe value and 124 * if not then an attacker would surely just generate a PNG with 0 instead. 125 */ 126 return 0; 127 } 128 129 /* Grab an unsigned 16-bit integer from a buffer in big-endian format. */ 130 png_uint_16 (PNGAPI 131 png_get_uint_16)(png_const_bytep buf) 132 { 133 /* ANSI-C requires an int value to accommodate at least 16 bits so this 134 * works and allows the compiler not to worry about possible narrowing 135 * on 32-bit systems. (Pre-ANSI systems did not make integers smaller 136 * than 16 bits either.) 137 */ 138 unsigned int val = 139 ((unsigned int)(*buf) << 8) + 140 ((unsigned int)(*(buf + 1))); 141 142 return (png_uint_16)val; 143 } 144 145 #endif /* READ_INT_FUNCTIONS */ 146 147 /* Read and check the PNG file signature */ 148 void /* PRIVATE */ 149 png_read_sig(png_structrp png_ptr, png_inforp info_ptr) 150 { 151 size_t num_checked, num_to_check; 152 153 /* Exit if the user application does not expect a signature. */ 154 if (png_ptr->sig_bytes >= 8) 155 return; 156 157 num_checked = png_ptr->sig_bytes; 158 num_to_check = 8 - num_checked; 159 160 #ifdef PNG_IO_STATE_SUPPORTED 161 png_ptr->io_state = PNG_IO_READING | PNG_IO_SIGNATURE; 162 #endif 163 164 /* The signature must be serialized in a single I/O call. */ 165 png_read_data(png_ptr, &(info_ptr->signature[num_checked]), num_to_check); 166 png_ptr->sig_bytes = 8; 167 168 if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check) != 0) 169 { 170 if (num_checked < 4 && 171 png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4)) 172 png_error(png_ptr, "Not a PNG file"); 173 else 174 png_error(png_ptr, "PNG file corrupted by ASCII conversion"); 175 } 176 if (num_checked < 3) 177 png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE; 178 } 179 180 /* Read the chunk header (length + type name). 181 * Put the type name into png_ptr->chunk_name, and return the length. 182 */ 183 png_uint_32 /* PRIVATE */ 184 png_read_chunk_header(png_structrp png_ptr) 185 { 186 png_byte buf[8]; 187 png_uint_32 length; 188 189 #ifdef PNG_IO_STATE_SUPPORTED 190 png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_HDR; 191 #endif 192 193 /* Read the length and the chunk name. 194 * This must be performed in a single I/O call. 195 */ 196 png_read_data(png_ptr, buf, 8); 197 length = png_get_uint_31(png_ptr, buf); 198 199 /* Put the chunk name into png_ptr->chunk_name. */ 200 png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(buf+4); 201 202 png_debug2(0, "Reading %lx chunk, length = %lu", 203 (unsigned long)png_ptr->chunk_name, (unsigned long)length); 204 205 /* Reset the crc and run it over the chunk name. */ 206 png_reset_crc(png_ptr); 207 png_calculate_crc(png_ptr, buf + 4, 4); 208 209 /* Check to see if chunk name is valid. */ 210 png_check_chunk_name(png_ptr, png_ptr->chunk_name); 211 212 /* Check for too-large chunk length */ 213 png_check_chunk_length(png_ptr, length); 214 215 #ifdef PNG_IO_STATE_SUPPORTED 216 png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_DATA; 217 #endif 218 219 return length; 220 } 221 222 /* Read data, and (optionally) run it through the CRC. */ 223 void /* PRIVATE */ 224 png_crc_read(png_structrp png_ptr, png_bytep buf, png_uint_32 length) 225 { 226 if (png_ptr == NULL) 227 return; 228 229 png_read_data(png_ptr, buf, length); 230 png_calculate_crc(png_ptr, buf, length); 231 } 232 233 /* Optionally skip data and then check the CRC. Depending on whether we 234 * are reading an ancillary or critical chunk, and how the program has set 235 * things up, we may calculate the CRC on the data and print a message. 236 * Returns '1' if there was a CRC error, '0' otherwise. 237 */ 238 int /* PRIVATE */ 239 png_crc_finish(png_structrp png_ptr, png_uint_32 skip) 240 { 241 /* The size of the local buffer for inflate is a good guess as to a 242 * reasonable size to use for buffering reads from the application. 243 */ 244 while (skip > 0) 245 { 246 png_uint_32 len; 247 png_byte tmpbuf[PNG_INFLATE_BUF_SIZE]; 248 249 len = (sizeof tmpbuf); 250 if (len > skip) 251 len = skip; 252 skip -= len; 253 254 png_crc_read(png_ptr, tmpbuf, len); 255 } 256 257 if (png_crc_error(png_ptr) != 0) 258 { 259 if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name) != 0 ? 260 (png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) == 0 : 261 (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_USE) != 0) 262 { 263 png_chunk_warning(png_ptr, "CRC error"); 264 } 265 266 else 267 png_chunk_error(png_ptr, "CRC error"); 268 269 return (1); 270 } 271 272 return (0); 273 } 274 275 /* Compare the CRC stored in the PNG file with that calculated by libpng from 276 * the data it has read thus far. 277 */ 278 int /* PRIVATE */ 279 png_crc_error(png_structrp png_ptr) 280 { 281 png_byte crc_bytes[4]; 282 png_uint_32 crc; 283 int need_crc = 1; 284 285 if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name) != 0) 286 { 287 if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) == 288 (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN)) 289 need_crc = 0; 290 } 291 292 else /* critical */ 293 { 294 if ((png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE) != 0) 295 need_crc = 0; 296 } 297 298 #ifdef PNG_IO_STATE_SUPPORTED 299 png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_CRC; 300 #endif 301 302 /* The chunk CRC must be serialized in a single I/O call. */ 303 png_read_data(png_ptr, crc_bytes, 4); 304 305 if (need_crc != 0) 306 { 307 crc = png_get_uint_32(crc_bytes); 308 return ((int)(crc != png_ptr->crc)); 309 } 310 311 else 312 return (0); 313 } 314 315 #if defined(PNG_READ_iCCP_SUPPORTED) || defined(PNG_READ_iTXt_SUPPORTED) ||\ 316 defined(PNG_READ_pCAL_SUPPORTED) || defined(PNG_READ_sCAL_SUPPORTED) ||\ 317 defined(PNG_READ_sPLT_SUPPORTED) || defined(PNG_READ_tEXt_SUPPORTED) ||\ 318 defined(PNG_READ_zTXt_SUPPORTED) || defined(PNG_SEQUENTIAL_READ_SUPPORTED) 319 /* Manage the read buffer; this simply reallocates the buffer if it is not small 320 * enough (or if it is not allocated). The routine returns a pointer to the 321 * buffer; if an error occurs and 'warn' is set the routine returns NULL, else 322 * it will call png_error (via png_malloc) on failure. (warn == 2 means 323 * 'silent'). 324 */ 325 static png_bytep 326 png_read_buffer(png_structrp png_ptr, png_alloc_size_t new_size, int warn) 327 { 328 png_bytep buffer = png_ptr->read_buffer; 329 330 if (buffer != NULL && new_size > png_ptr->read_buffer_size) 331 { 332 png_ptr->read_buffer = NULL; 333 png_ptr->read_buffer = NULL; 334 png_ptr->read_buffer_size = 0; 335 png_free(png_ptr, buffer); 336 buffer = NULL; 337 } 338 339 if (buffer == NULL) 340 { 341 buffer = png_voidcast(png_bytep, png_malloc_base(png_ptr, new_size)); 342 343 if (buffer != NULL) 344 { 345 memset(buffer, 0, new_size); /* just in case */ 346 png_ptr->read_buffer = buffer; 347 png_ptr->read_buffer_size = new_size; 348 } 349 350 else if (warn < 2) /* else silent */ 351 { 352 if (warn != 0) 353 png_chunk_warning(png_ptr, "insufficient memory to read chunk"); 354 355 else 356 png_chunk_error(png_ptr, "insufficient memory to read chunk"); 357 } 358 } 359 360 return buffer; 361 } 362 #endif /* READ_iCCP|iTXt|pCAL|sCAL|sPLT|tEXt|zTXt|SEQUENTIAL_READ */ 363 364 /* png_inflate_claim: claim the zstream for some nefarious purpose that involves 365 * decompression. Returns Z_OK on success, else a zlib error code. It checks 366 * the owner but, in final release builds, just issues a warning if some other 367 * chunk apparently owns the stream. Prior to release it does a png_error. 368 */ 369 static int 370 png_inflate_claim(png_structrp png_ptr, png_uint_32 owner) 371 { 372 if (png_ptr->zowner != 0) 373 { 374 char msg[64]; 375 376 PNG_STRING_FROM_CHUNK(msg, png_ptr->zowner); 377 /* So the message that results is "<chunk> using zstream"; this is an 378 * internal error, but is very useful for debugging. i18n requirements 379 * are minimal. 380 */ 381 (void)png_safecat(msg, (sizeof msg), 4, " using zstream"); 382 #if PNG_RELEASE_BUILD 383 png_chunk_warning(png_ptr, msg); 384 png_ptr->zowner = 0; 385 #else 386 png_chunk_error(png_ptr, msg); 387 #endif 388 } 389 390 /* Implementation note: unlike 'png_deflate_claim' this internal function 391 * does not take the size of the data as an argument. Some efficiency could 392 * be gained by using this when it is known *if* the zlib stream itself does 393 * not record the number; however, this is an illusion: the original writer 394 * of the PNG may have selected a lower window size, and we really must 395 * follow that because, for systems with with limited capabilities, we 396 * would otherwise reject the application's attempts to use a smaller window 397 * size (zlib doesn't have an interface to say "this or lower"!). 398 * 399 * inflateReset2 was added to zlib 1.2.4; before this the window could not be 400 * reset, therefore it is necessary to always allocate the maximum window 401 * size with earlier zlibs just in case later compressed chunks need it. 402 */ 403 { 404 int ret; /* zlib return code */ 405 #if ZLIB_VERNUM >= 0x1240 406 int window_bits = 0; 407 408 # if defined(PNG_SET_OPTION_SUPPORTED) && defined(PNG_MAXIMUM_INFLATE_WINDOW) 409 if (((png_ptr->options >> PNG_MAXIMUM_INFLATE_WINDOW) & 3) == 410 PNG_OPTION_ON) 411 { 412 window_bits = 15; 413 png_ptr->zstream_start = 0; /* fixed window size */ 414 } 415 416 else 417 { 418 png_ptr->zstream_start = 1; 419 } 420 # endif 421 422 #endif /* ZLIB_VERNUM >= 0x1240 */ 423 424 /* Set this for safety, just in case the previous owner left pointers to 425 * memory allocations. 426 */ 427 png_ptr->zstream.next_in = NULL; 428 png_ptr->zstream.avail_in = 0; 429 png_ptr->zstream.next_out = NULL; 430 png_ptr->zstream.avail_out = 0; 431 432 if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0) 433 { 434 #if ZLIB_VERNUM >= 0x1240 435 ret = inflateReset2(&png_ptr->zstream, window_bits); 436 #else 437 ret = inflateReset(&png_ptr->zstream); 438 #endif 439 } 440 441 else 442 { 443 #if ZLIB_VERNUM >= 0x1240 444 ret = inflateInit2(&png_ptr->zstream, window_bits); 445 #else 446 ret = inflateInit(&png_ptr->zstream); 447 #endif 448 449 if (ret == Z_OK) 450 png_ptr->flags |= PNG_FLAG_ZSTREAM_INITIALIZED; 451 } 452 453 #if ZLIB_VERNUM >= 0x1290 && \ 454 defined(PNG_SET_OPTION_SUPPORTED) && defined(PNG_IGNORE_ADLER32) 455 if (((png_ptr->options >> PNG_IGNORE_ADLER32) & 3) == PNG_OPTION_ON) 456 /* Turn off validation of the ADLER32 checksum in IDAT chunks */ 457 ret = inflateValidate(&png_ptr->zstream, 0); 458 #endif 459 460 if (ret == Z_OK) 461 png_ptr->zowner = owner; 462 463 else 464 png_zstream_error(png_ptr, ret); 465 466 return ret; 467 } 468 469 #ifdef window_bits 470 # undef window_bits 471 #endif 472 } 473 474 #if ZLIB_VERNUM >= 0x1240 475 /* Handle the start of the inflate stream if we called inflateInit2(strm,0); 476 * in this case some zlib versions skip validation of the CINFO field and, in 477 * certain circumstances, libpng may end up displaying an invalid image, in 478 * contrast to implementations that call zlib in the normal way (e.g. libpng 479 * 1.5). 480 */ 481 int /* PRIVATE */ 482 png_zlib_inflate(png_structrp png_ptr, int flush) 483 { 484 if (png_ptr->zstream_start && png_ptr->zstream.avail_in > 0) 485 { 486 if ((*png_ptr->zstream.next_in >> 4) > 7) 487 { 488 png_ptr->zstream.msg = "invalid window size (libpng)"; 489 return Z_DATA_ERROR; 490 } 491 492 png_ptr->zstream_start = 0; 493 } 494 495 return inflate(&png_ptr->zstream, flush); 496 } 497 #endif /* Zlib >= 1.2.4 */ 498 499 #ifdef PNG_READ_COMPRESSED_TEXT_SUPPORTED 500 #if defined(PNG_READ_zTXt_SUPPORTED) || defined (PNG_READ_iTXt_SUPPORTED) 501 /* png_inflate now returns zlib error codes including Z_OK and Z_STREAM_END to 502 * allow the caller to do multiple calls if required. If the 'finish' flag is 503 * set Z_FINISH will be passed to the final inflate() call and Z_STREAM_END must 504 * be returned or there has been a problem, otherwise Z_SYNC_FLUSH is used and 505 * Z_OK or Z_STREAM_END will be returned on success. 506 * 507 * The input and output sizes are updated to the actual amounts of data consumed 508 * or written, not the amount available (as in a z_stream). The data pointers 509 * are not changed, so the next input is (data+input_size) and the next 510 * available output is (output+output_size). 511 */ 512 static int 513 png_inflate(png_structrp png_ptr, png_uint_32 owner, int finish, 514 /* INPUT: */ png_const_bytep input, png_uint_32p input_size_ptr, 515 /* OUTPUT: */ png_bytep output, png_alloc_size_t *output_size_ptr) 516 { 517 if (png_ptr->zowner == owner) /* Else not claimed */ 518 { 519 int ret; 520 png_alloc_size_t avail_out = *output_size_ptr; 521 png_uint_32 avail_in = *input_size_ptr; 522 523 /* zlib can't necessarily handle more than 65535 bytes at once (i.e. it 524 * can't even necessarily handle 65536 bytes) because the type uInt is 525 * "16 bits or more". Consequently it is necessary to chunk the input to 526 * zlib. This code uses ZLIB_IO_MAX, from pngpriv.h, as the maximum (the 527 * maximum value that can be stored in a uInt.) It is possible to set 528 * ZLIB_IO_MAX to a lower value in pngpriv.h and this may sometimes have 529 * a performance advantage, because it reduces the amount of data accessed 530 * at each step and that may give the OS more time to page it in. 531 */ 532 png_ptr->zstream.next_in = PNGZ_INPUT_CAST(input); 533 /* avail_in and avail_out are set below from 'size' */ 534 png_ptr->zstream.avail_in = 0; 535 png_ptr->zstream.avail_out = 0; 536 537 /* Read directly into the output if it is available (this is set to 538 * a local buffer below if output is NULL). 539 */ 540 if (output != NULL) 541 png_ptr->zstream.next_out = output; 542 543 do 544 { 545 uInt avail; 546 Byte local_buffer[PNG_INFLATE_BUF_SIZE]; 547 548 /* zlib INPUT BUFFER */ 549 /* The setting of 'avail_in' used to be outside the loop; by setting it 550 * inside it is possible to chunk the input to zlib and simply rely on 551 * zlib to advance the 'next_in' pointer. This allows arbitrary 552 * amounts of data to be passed through zlib at the unavoidable cost of 553 * requiring a window save (memcpy of up to 32768 output bytes) 554 * every ZLIB_IO_MAX input bytes. 555 */ 556 avail_in += png_ptr->zstream.avail_in; /* not consumed last time */ 557 558 avail = ZLIB_IO_MAX; 559 560 if (avail_in < avail) 561 avail = (uInt)avail_in; /* safe: < than ZLIB_IO_MAX */ 562 563 avail_in -= avail; 564 png_ptr->zstream.avail_in = avail; 565 566 /* zlib OUTPUT BUFFER */ 567 avail_out += png_ptr->zstream.avail_out; /* not written last time */ 568 569 avail = ZLIB_IO_MAX; /* maximum zlib can process */ 570 571 if (output == NULL) 572 { 573 /* Reset the output buffer each time round if output is NULL and 574 * make available the full buffer, up to 'remaining_space' 575 */ 576 png_ptr->zstream.next_out = local_buffer; 577 if ((sizeof local_buffer) < avail) 578 avail = (sizeof local_buffer); 579 } 580 581 if (avail_out < avail) 582 avail = (uInt)avail_out; /* safe: < ZLIB_IO_MAX */ 583 584 png_ptr->zstream.avail_out = avail; 585 avail_out -= avail; 586 587 /* zlib inflate call */ 588 /* In fact 'avail_out' may be 0 at this point, that happens at the end 589 * of the read when the final LZ end code was not passed at the end of 590 * the previous chunk of input data. Tell zlib if we have reached the 591 * end of the output buffer. 592 */ 593 ret = PNG_INFLATE(png_ptr, avail_out > 0 ? Z_NO_FLUSH : 594 (finish ? Z_FINISH : Z_SYNC_FLUSH)); 595 } while (ret == Z_OK); 596 597 /* For safety kill the local buffer pointer now */ 598 if (output == NULL) 599 png_ptr->zstream.next_out = NULL; 600 601 /* Claw back the 'size' and 'remaining_space' byte counts. */ 602 avail_in += png_ptr->zstream.avail_in; 603 avail_out += png_ptr->zstream.avail_out; 604 605 /* Update the input and output sizes; the updated values are the amount 606 * consumed or written, effectively the inverse of what zlib uses. 607 */ 608 if (avail_out > 0) 609 *output_size_ptr -= avail_out; 610 611 if (avail_in > 0) 612 *input_size_ptr -= avail_in; 613 614 /* Ensure png_ptr->zstream.msg is set (even in the success case!) */ 615 png_zstream_error(png_ptr, ret); 616 return ret; 617 } 618 619 else 620 { 621 /* This is a bad internal error. The recovery assigns to the zstream msg 622 * pointer, which is not owned by the caller, but this is safe; it's only 623 * used on errors! 624 */ 625 png_ptr->zstream.msg = PNGZ_MSG_CAST("zstream unclaimed"); 626 return Z_STREAM_ERROR; 627 } 628 } 629 630 /* 631 * Decompress trailing data in a chunk. The assumption is that read_buffer 632 * points at an allocated area holding the contents of a chunk with a 633 * trailing compressed part. What we get back is an allocated area 634 * holding the original prefix part and an uncompressed version of the 635 * trailing part (the malloc area passed in is freed). 636 */ 637 static int 638 png_decompress_chunk(png_structrp png_ptr, 639 png_uint_32 chunklength, png_uint_32 prefix_size, 640 png_alloc_size_t *newlength /* must be initialized to the maximum! */, 641 int terminate /*add a '\0' to the end of the uncompressed data*/) 642 { 643 /* TODO: implement different limits for different types of chunk. 644 * 645 * The caller supplies *newlength set to the maximum length of the 646 * uncompressed data, but this routine allocates space for the prefix and 647 * maybe a '\0' terminator too. We have to assume that 'prefix_size' is 648 * limited only by the maximum chunk size. 649 */ 650 png_alloc_size_t limit = PNG_SIZE_MAX; 651 652 # ifdef PNG_SET_USER_LIMITS_SUPPORTED 653 if (png_ptr->user_chunk_malloc_max > 0 && 654 png_ptr->user_chunk_malloc_max < limit) 655 limit = png_ptr->user_chunk_malloc_max; 656 # elif PNG_USER_CHUNK_MALLOC_MAX > 0 657 if (PNG_USER_CHUNK_MALLOC_MAX < limit) 658 limit = PNG_USER_CHUNK_MALLOC_MAX; 659 # endif 660 661 if (limit >= prefix_size + (terminate != 0)) 662 { 663 int ret; 664 665 limit -= prefix_size + (terminate != 0); 666 667 if (limit < *newlength) 668 *newlength = limit; 669 670 /* Now try to claim the stream. */ 671 ret = png_inflate_claim(png_ptr, png_ptr->chunk_name); 672 673 if (ret == Z_OK) 674 { 675 png_uint_32 lzsize = chunklength - prefix_size; 676 677 ret = png_inflate(png_ptr, png_ptr->chunk_name, 1/*finish*/, 678 /* input: */ png_ptr->read_buffer + prefix_size, &lzsize, 679 /* output: */ NULL, newlength); 680 681 if (ret == Z_STREAM_END) 682 { 683 /* Use 'inflateReset' here, not 'inflateReset2' because this 684 * preserves the previously decided window size (otherwise it would 685 * be necessary to store the previous window size.) In practice 686 * this doesn't matter anyway, because png_inflate will call inflate 687 * with Z_FINISH in almost all cases, so the window will not be 688 * maintained. 689 */ 690 if (inflateReset(&png_ptr->zstream) == Z_OK) 691 { 692 /* Because of the limit checks above we know that the new, 693 * expanded, size will fit in a size_t (let alone an 694 * png_alloc_size_t). Use png_malloc_base here to avoid an 695 * extra OOM message. 696 */ 697 png_alloc_size_t new_size = *newlength; 698 png_alloc_size_t buffer_size = prefix_size + new_size + 699 (terminate != 0); 700 png_bytep text = png_voidcast(png_bytep, png_malloc_base(png_ptr, 701 buffer_size)); 702 703 if (text != NULL) 704 { 705 memset(text, 0, buffer_size); 706 707 ret = png_inflate(png_ptr, png_ptr->chunk_name, 1/*finish*/, 708 png_ptr->read_buffer + prefix_size, &lzsize, 709 text + prefix_size, newlength); 710 711 if (ret == Z_STREAM_END) 712 { 713 if (new_size == *newlength) 714 { 715 if (terminate != 0) 716 text[prefix_size + *newlength] = 0; 717 718 if (prefix_size > 0) 719 memcpy(text, png_ptr->read_buffer, prefix_size); 720 721 { 722 png_bytep old_ptr = png_ptr->read_buffer; 723 724 png_ptr->read_buffer = text; 725 png_ptr->read_buffer_size = buffer_size; 726 text = old_ptr; /* freed below */ 727 } 728 } 729 730 else 731 { 732 /* The size changed on the second read, there can be no 733 * guarantee that anything is correct at this point. 734 * The 'msg' pointer has been set to "unexpected end of 735 * LZ stream", which is fine, but return an error code 736 * that the caller won't accept. 737 */ 738 ret = PNG_UNEXPECTED_ZLIB_RETURN; 739 } 740 } 741 742 else if (ret == Z_OK) 743 ret = PNG_UNEXPECTED_ZLIB_RETURN; /* for safety */ 744 745 /* Free the text pointer (this is the old read_buffer on 746 * success) 747 */ 748 png_free(png_ptr, text); 749 750 /* This really is very benign, but it's still an error because 751 * the extra space may otherwise be used as a Trojan Horse. 752 */ 753 if (ret == Z_STREAM_END && 754 chunklength - prefix_size != lzsize) 755 png_chunk_benign_error(png_ptr, "extra compressed data"); 756 } 757 758 else 759 { 760 /* Out of memory allocating the buffer */ 761 ret = Z_MEM_ERROR; 762 png_zstream_error(png_ptr, Z_MEM_ERROR); 763 } 764 } 765 766 else 767 { 768 /* inflateReset failed, store the error message */ 769 png_zstream_error(png_ptr, ret); 770 ret = PNG_UNEXPECTED_ZLIB_RETURN; 771 } 772 } 773 774 else if (ret == Z_OK) 775 ret = PNG_UNEXPECTED_ZLIB_RETURN; 776 777 /* Release the claimed stream */ 778 png_ptr->zowner = 0; 779 } 780 781 else /* the claim failed */ if (ret == Z_STREAM_END) /* impossible! */ 782 ret = PNG_UNEXPECTED_ZLIB_RETURN; 783 784 return ret; 785 } 786 787 else 788 { 789 /* Application/configuration limits exceeded */ 790 png_zstream_error(png_ptr, Z_MEM_ERROR); 791 return Z_MEM_ERROR; 792 } 793 } 794 #endif /* READ_zTXt || READ_iTXt */ 795 #endif /* READ_COMPRESSED_TEXT */ 796 797 #ifdef PNG_READ_iCCP_SUPPORTED 798 /* Perform a partial read and decompress, producing 'avail_out' bytes and 799 * reading from the current chunk as required. 800 */ 801 static int 802 png_inflate_read(png_structrp png_ptr, png_bytep read_buffer, uInt read_size, 803 png_uint_32p chunk_bytes, png_bytep next_out, png_alloc_size_t *out_size, 804 int finish) 805 { 806 if (png_ptr->zowner == png_ptr->chunk_name) 807 { 808 int ret; 809 810 /* next_in and avail_in must have been initialized by the caller. */ 811 png_ptr->zstream.next_out = next_out; 812 png_ptr->zstream.avail_out = 0; /* set in the loop */ 813 814 do 815 { 816 if (png_ptr->zstream.avail_in == 0) 817 { 818 if (read_size > *chunk_bytes) 819 read_size = (uInt)*chunk_bytes; 820 *chunk_bytes -= read_size; 821 822 if (read_size > 0) 823 png_crc_read(png_ptr, read_buffer, read_size); 824 825 png_ptr->zstream.next_in = read_buffer; 826 png_ptr->zstream.avail_in = read_size; 827 } 828 829 if (png_ptr->zstream.avail_out == 0) 830 { 831 uInt avail = ZLIB_IO_MAX; 832 if (avail > *out_size) 833 avail = (uInt)*out_size; 834 *out_size -= avail; 835 836 png_ptr->zstream.avail_out = avail; 837 } 838 839 /* Use Z_SYNC_FLUSH when there is no more chunk data to ensure that all 840 * the available output is produced; this allows reading of truncated 841 * streams. 842 */ 843 ret = PNG_INFLATE(png_ptr, *chunk_bytes > 0 ? 844 Z_NO_FLUSH : (finish ? Z_FINISH : Z_SYNC_FLUSH)); 845 } 846 while (ret == Z_OK && (*out_size > 0 || png_ptr->zstream.avail_out > 0)); 847 848 *out_size += png_ptr->zstream.avail_out; 849 png_ptr->zstream.avail_out = 0; /* Should not be required, but is safe */ 850 851 /* Ensure the error message pointer is always set: */ 852 png_zstream_error(png_ptr, ret); 853 return ret; 854 } 855 856 else 857 { 858 png_ptr->zstream.msg = PNGZ_MSG_CAST("zstream unclaimed"); 859 return Z_STREAM_ERROR; 860 } 861 } 862 #endif /* READ_iCCP */ 863 864 /* Read and check the IDHR chunk */ 865 866 void /* PRIVATE */ 867 png_handle_IHDR(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 868 { 869 png_byte buf[13]; 870 png_uint_32 width, height; 871 int bit_depth, color_type, compression_type, filter_type; 872 int interlace_type; 873 874 png_debug(1, "in png_handle_IHDR"); 875 876 if ((png_ptr->mode & PNG_HAVE_IHDR) != 0) 877 png_chunk_error(png_ptr, "out of place"); 878 879 /* Check the length */ 880 if (length != 13) 881 png_chunk_error(png_ptr, "invalid"); 882 883 png_ptr->mode |= PNG_HAVE_IHDR; 884 885 png_crc_read(png_ptr, buf, 13); 886 png_crc_finish(png_ptr, 0); 887 888 width = png_get_uint_31(png_ptr, buf); 889 height = png_get_uint_31(png_ptr, buf + 4); 890 bit_depth = buf[8]; 891 color_type = buf[9]; 892 compression_type = buf[10]; 893 filter_type = buf[11]; 894 interlace_type = buf[12]; 895 896 /* Set internal variables */ 897 png_ptr->width = width; 898 png_ptr->height = height; 899 png_ptr->bit_depth = (png_byte)bit_depth; 900 png_ptr->interlaced = (png_byte)interlace_type; 901 png_ptr->color_type = (png_byte)color_type; 902 #ifdef PNG_MNG_FEATURES_SUPPORTED 903 png_ptr->filter_type = (png_byte)filter_type; 904 #endif 905 png_ptr->compression_type = (png_byte)compression_type; 906 907 /* Find number of channels */ 908 switch (png_ptr->color_type) 909 { 910 default: /* invalid, png_set_IHDR calls png_error */ 911 case PNG_COLOR_TYPE_GRAY: 912 case PNG_COLOR_TYPE_PALETTE: 913 png_ptr->channels = 1; 914 break; 915 916 case PNG_COLOR_TYPE_RGB: 917 png_ptr->channels = 3; 918 break; 919 920 case PNG_COLOR_TYPE_GRAY_ALPHA: 921 png_ptr->channels = 2; 922 break; 923 924 case PNG_COLOR_TYPE_RGB_ALPHA: 925 png_ptr->channels = 4; 926 break; 927 } 928 929 /* Set up other useful info */ 930 png_ptr->pixel_depth = (png_byte)(png_ptr->bit_depth * png_ptr->channels); 931 png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->width); 932 png_debug1(3, "bit_depth = %d", png_ptr->bit_depth); 933 png_debug1(3, "channels = %d", png_ptr->channels); 934 png_debug1(3, "rowbytes = %lu", (unsigned long)png_ptr->rowbytes); 935 png_set_IHDR(png_ptr, info_ptr, width, height, bit_depth, 936 color_type, interlace_type, compression_type, filter_type); 937 } 938 939 /* Read and check the palette */ 940 void /* PRIVATE */ 941 png_handle_PLTE(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 942 { 943 png_color palette[PNG_MAX_PALETTE_LENGTH]; 944 int max_palette_length, num, i; 945 #ifdef PNG_POINTER_INDEXING_SUPPORTED 946 png_colorp pal_ptr; 947 #endif 948 949 png_debug(1, "in png_handle_PLTE"); 950 951 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 952 png_chunk_error(png_ptr, "missing IHDR"); 953 954 /* Moved to before the 'after IDAT' check below because otherwise duplicate 955 * PLTE chunks are potentially ignored (the spec says there shall not be more 956 * than one PLTE, the error is not treated as benign, so this check trumps 957 * the requirement that PLTE appears before IDAT.) 958 */ 959 else if ((png_ptr->mode & PNG_HAVE_PLTE) != 0) 960 png_chunk_error(png_ptr, "duplicate"); 961 962 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) 963 { 964 /* This is benign because the non-benign error happened before, when an 965 * IDAT was encountered in a color-mapped image with no PLTE. 966 */ 967 png_crc_finish(png_ptr, length); 968 png_chunk_benign_error(png_ptr, "out of place"); 969 return; 970 } 971 972 png_ptr->mode |= PNG_HAVE_PLTE; 973 974 if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0) 975 { 976 png_crc_finish(png_ptr, length); 977 png_chunk_benign_error(png_ptr, "ignored in grayscale PNG"); 978 return; 979 } 980 981 #ifndef PNG_READ_OPT_PLTE_SUPPORTED 982 if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE) 983 { 984 png_crc_finish(png_ptr, length); 985 return; 986 } 987 #endif 988 989 if (length > 3*PNG_MAX_PALETTE_LENGTH || length % 3) 990 { 991 png_crc_finish(png_ptr, length); 992 993 if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE) 994 png_chunk_benign_error(png_ptr, "invalid"); 995 996 else 997 png_chunk_error(png_ptr, "invalid"); 998 999 return; 1000 } 1001 1002 /* The cast is safe because 'length' is less than 3*PNG_MAX_PALETTE_LENGTH */ 1003 num = (int)length / 3; 1004 1005 /* If the palette has 256 or fewer entries but is too large for the bit 1006 * depth, we don't issue an error, to preserve the behavior of previous 1007 * libpng versions. We silently truncate the unused extra palette entries 1008 * here. 1009 */ 1010 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) 1011 max_palette_length = (1 << png_ptr->bit_depth); 1012 else 1013 max_palette_length = PNG_MAX_PALETTE_LENGTH; 1014 1015 if (num > max_palette_length) 1016 num = max_palette_length; 1017 1018 #ifdef PNG_POINTER_INDEXING_SUPPORTED 1019 for (i = 0, pal_ptr = palette; i < num; i++, pal_ptr++) 1020 { 1021 png_byte buf[3]; 1022 1023 png_crc_read(png_ptr, buf, 3); 1024 pal_ptr->red = buf[0]; 1025 pal_ptr->green = buf[1]; 1026 pal_ptr->blue = buf[2]; 1027 } 1028 #else 1029 for (i = 0; i < num; i++) 1030 { 1031 png_byte buf[3]; 1032 1033 png_crc_read(png_ptr, buf, 3); 1034 /* Don't depend upon png_color being any order */ 1035 palette[i].red = buf[0]; 1036 palette[i].green = buf[1]; 1037 palette[i].blue = buf[2]; 1038 } 1039 #endif 1040 1041 /* If we actually need the PLTE chunk (ie for a paletted image), we do 1042 * whatever the normal CRC configuration tells us. However, if we 1043 * have an RGB image, the PLTE can be considered ancillary, so 1044 * we will act as though it is. 1045 */ 1046 #ifndef PNG_READ_OPT_PLTE_SUPPORTED 1047 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) 1048 #endif 1049 { 1050 png_crc_finish(png_ptr, (png_uint_32) (length - (unsigned int)num * 3)); 1051 } 1052 1053 #ifndef PNG_READ_OPT_PLTE_SUPPORTED 1054 else if (png_crc_error(png_ptr) != 0) /* Only if we have a CRC error */ 1055 { 1056 /* If we don't want to use the data from an ancillary chunk, 1057 * we have two options: an error abort, or a warning and we 1058 * ignore the data in this chunk (which should be OK, since 1059 * it's considered ancillary for a RGB or RGBA image). 1060 * 1061 * IMPLEMENTATION NOTE: this is only here because png_crc_finish uses the 1062 * chunk type to determine whether to check the ancillary or the critical 1063 * flags. 1064 */ 1065 if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_USE) == 0) 1066 { 1067 if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) != 0) 1068 return; 1069 1070 else 1071 png_chunk_error(png_ptr, "CRC error"); 1072 } 1073 1074 /* Otherwise, we (optionally) emit a warning and use the chunk. */ 1075 else if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) == 0) 1076 png_chunk_warning(png_ptr, "CRC error"); 1077 } 1078 #endif 1079 1080 /* TODO: png_set_PLTE has the side effect of setting png_ptr->palette to its 1081 * own copy of the palette. This has the side effect that when png_start_row 1082 * is called (this happens after any call to png_read_update_info) the 1083 * info_ptr palette gets changed. This is extremely unexpected and 1084 * confusing. 1085 * 1086 * Fix this by not sharing the palette in this way. 1087 */ 1088 png_set_PLTE(png_ptr, info_ptr, palette, num); 1089 1090 /* The three chunks, bKGD, hIST and tRNS *must* appear after PLTE and before 1091 * IDAT. Prior to 1.6.0 this was not checked; instead the code merely 1092 * checked the apparent validity of a tRNS chunk inserted before PLTE on a 1093 * palette PNG. 1.6.0 attempts to rigorously follow the standard and 1094 * therefore does a benign error if the erroneous condition is detected *and* 1095 * cancels the tRNS if the benign error returns. The alternative is to 1096 * amend the standard since it would be rather hypocritical of the standards 1097 * maintainers to ignore it. 1098 */ 1099 #ifdef PNG_READ_tRNS_SUPPORTED 1100 if (png_ptr->num_trans > 0 || 1101 (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS) != 0)) 1102 { 1103 /* Cancel this because otherwise it would be used if the transforms 1104 * require it. Don't cancel the 'valid' flag because this would prevent 1105 * detection of duplicate chunks. 1106 */ 1107 png_ptr->num_trans = 0; 1108 1109 if (info_ptr != NULL) 1110 info_ptr->num_trans = 0; 1111 1112 png_chunk_benign_error(png_ptr, "tRNS must be after"); 1113 } 1114 #endif 1115 1116 #ifdef PNG_READ_hIST_SUPPORTED 1117 if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST) != 0) 1118 png_chunk_benign_error(png_ptr, "hIST must be after"); 1119 #endif 1120 1121 #ifdef PNG_READ_bKGD_SUPPORTED 1122 if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD) != 0) 1123 png_chunk_benign_error(png_ptr, "bKGD must be after"); 1124 #endif 1125 } 1126 1127 void /* PRIVATE */ 1128 png_handle_IEND(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 1129 { 1130 png_debug(1, "in png_handle_IEND"); 1131 1132 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0 || 1133 (png_ptr->mode & PNG_HAVE_IDAT) == 0) 1134 png_chunk_error(png_ptr, "out of place"); 1135 1136 png_ptr->mode |= (PNG_AFTER_IDAT | PNG_HAVE_IEND); 1137 1138 png_crc_finish(png_ptr, length); 1139 1140 if (length != 0) 1141 png_chunk_benign_error(png_ptr, "invalid"); 1142 1143 PNG_UNUSED(info_ptr) 1144 } 1145 1146 #ifdef PNG_READ_gAMA_SUPPORTED 1147 void /* PRIVATE */ 1148 png_handle_gAMA(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 1149 { 1150 png_fixed_point igamma; 1151 png_byte buf[4]; 1152 1153 png_debug(1, "in png_handle_gAMA"); 1154 1155 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 1156 png_chunk_error(png_ptr, "missing IHDR"); 1157 1158 else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0) 1159 { 1160 png_crc_finish(png_ptr, length); 1161 png_chunk_benign_error(png_ptr, "out of place"); 1162 return; 1163 } 1164 1165 if (length != 4) 1166 { 1167 png_crc_finish(png_ptr, length); 1168 png_chunk_benign_error(png_ptr, "invalid"); 1169 return; 1170 } 1171 1172 png_crc_read(png_ptr, buf, 4); 1173 1174 if (png_crc_finish(png_ptr, 0) != 0) 1175 return; 1176 1177 igamma = png_get_fixed_point(NULL, buf); 1178 1179 png_colorspace_set_gamma(png_ptr, &png_ptr->colorspace, igamma); 1180 png_colorspace_sync(png_ptr, info_ptr); 1181 } 1182 #endif 1183 1184 #ifdef PNG_READ_sBIT_SUPPORTED 1185 void /* PRIVATE */ 1186 png_handle_sBIT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 1187 { 1188 unsigned int truelen, i; 1189 png_byte sample_depth; 1190 png_byte buf[4]; 1191 1192 png_debug(1, "in png_handle_sBIT"); 1193 1194 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 1195 png_chunk_error(png_ptr, "missing IHDR"); 1196 1197 else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0) 1198 { 1199 png_crc_finish(png_ptr, length); 1200 png_chunk_benign_error(png_ptr, "out of place"); 1201 return; 1202 } 1203 1204 if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sBIT) != 0) 1205 { 1206 png_crc_finish(png_ptr, length); 1207 png_chunk_benign_error(png_ptr, "duplicate"); 1208 return; 1209 } 1210 1211 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) 1212 { 1213 truelen = 3; 1214 sample_depth = 8; 1215 } 1216 1217 else 1218 { 1219 truelen = png_ptr->channels; 1220 sample_depth = png_ptr->bit_depth; 1221 } 1222 1223 if (length != truelen || length > 4) 1224 { 1225 png_chunk_benign_error(png_ptr, "invalid"); 1226 png_crc_finish(png_ptr, length); 1227 return; 1228 } 1229 1230 buf[0] = buf[1] = buf[2] = buf[3] = sample_depth; 1231 png_crc_read(png_ptr, buf, truelen); 1232 1233 if (png_crc_finish(png_ptr, 0) != 0) 1234 return; 1235 1236 for (i=0; i<truelen; ++i) 1237 { 1238 if (buf[i] == 0 || buf[i] > sample_depth) 1239 { 1240 png_chunk_benign_error(png_ptr, "invalid"); 1241 return; 1242 } 1243 } 1244 1245 if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0) 1246 { 1247 png_ptr->sig_bit.red = buf[0]; 1248 png_ptr->sig_bit.green = buf[1]; 1249 png_ptr->sig_bit.blue = buf[2]; 1250 png_ptr->sig_bit.alpha = buf[3]; 1251 } 1252 1253 else 1254 { 1255 png_ptr->sig_bit.gray = buf[0]; 1256 png_ptr->sig_bit.red = buf[0]; 1257 png_ptr->sig_bit.green = buf[0]; 1258 png_ptr->sig_bit.blue = buf[0]; 1259 png_ptr->sig_bit.alpha = buf[1]; 1260 } 1261 1262 png_set_sBIT(png_ptr, info_ptr, &(png_ptr->sig_bit)); 1263 } 1264 #endif 1265 1266 #ifdef PNG_READ_cHRM_SUPPORTED 1267 void /* PRIVATE */ 1268 png_handle_cHRM(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 1269 { 1270 png_byte buf[32]; 1271 png_xy xy; 1272 1273 png_debug(1, "in png_handle_cHRM"); 1274 1275 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 1276 png_chunk_error(png_ptr, "missing IHDR"); 1277 1278 else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0) 1279 { 1280 png_crc_finish(png_ptr, length); 1281 png_chunk_benign_error(png_ptr, "out of place"); 1282 return; 1283 } 1284 1285 if (length != 32) 1286 { 1287 png_crc_finish(png_ptr, length); 1288 png_chunk_benign_error(png_ptr, "invalid"); 1289 return; 1290 } 1291 1292 png_crc_read(png_ptr, buf, 32); 1293 1294 if (png_crc_finish(png_ptr, 0) != 0) 1295 return; 1296 1297 xy.whitex = png_get_fixed_point(NULL, buf); 1298 xy.whitey = png_get_fixed_point(NULL, buf + 4); 1299 xy.redx = png_get_fixed_point(NULL, buf + 8); 1300 xy.redy = png_get_fixed_point(NULL, buf + 12); 1301 xy.greenx = png_get_fixed_point(NULL, buf + 16); 1302 xy.greeny = png_get_fixed_point(NULL, buf + 20); 1303 xy.bluex = png_get_fixed_point(NULL, buf + 24); 1304 xy.bluey = png_get_fixed_point(NULL, buf + 28); 1305 1306 if (xy.whitex == PNG_FIXED_ERROR || 1307 xy.whitey == PNG_FIXED_ERROR || 1308 xy.redx == PNG_FIXED_ERROR || 1309 xy.redy == PNG_FIXED_ERROR || 1310 xy.greenx == PNG_FIXED_ERROR || 1311 xy.greeny == PNG_FIXED_ERROR || 1312 xy.bluex == PNG_FIXED_ERROR || 1313 xy.bluey == PNG_FIXED_ERROR) 1314 { 1315 png_chunk_benign_error(png_ptr, "invalid values"); 1316 return; 1317 } 1318 1319 /* If a colorspace error has already been output skip this chunk */ 1320 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0) 1321 return; 1322 1323 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_FROM_cHRM) != 0) 1324 { 1325 png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID; 1326 png_colorspace_sync(png_ptr, info_ptr); 1327 png_chunk_benign_error(png_ptr, "duplicate"); 1328 return; 1329 } 1330 1331 png_ptr->colorspace.flags |= PNG_COLORSPACE_FROM_cHRM; 1332 (void)png_colorspace_set_chromaticities(png_ptr, &png_ptr->colorspace, &xy, 1333 1/*prefer cHRM values*/); 1334 png_colorspace_sync(png_ptr, info_ptr); 1335 } 1336 #endif 1337 1338 #ifdef PNG_READ_sRGB_SUPPORTED 1339 void /* PRIVATE */ 1340 png_handle_sRGB(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 1341 { 1342 png_byte intent; 1343 1344 png_debug(1, "in png_handle_sRGB"); 1345 1346 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 1347 png_chunk_error(png_ptr, "missing IHDR"); 1348 1349 else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0) 1350 { 1351 png_crc_finish(png_ptr, length); 1352 png_chunk_benign_error(png_ptr, "out of place"); 1353 return; 1354 } 1355 1356 if (length != 1) 1357 { 1358 png_crc_finish(png_ptr, length); 1359 png_chunk_benign_error(png_ptr, "invalid"); 1360 return; 1361 } 1362 1363 png_crc_read(png_ptr, &intent, 1); 1364 1365 if (png_crc_finish(png_ptr, 0) != 0) 1366 return; 1367 1368 /* If a colorspace error has already been output skip this chunk */ 1369 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0) 1370 return; 1371 1372 /* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect 1373 * this. 1374 */ 1375 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_INTENT) != 0) 1376 { 1377 png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID; 1378 png_colorspace_sync(png_ptr, info_ptr); 1379 png_chunk_benign_error(png_ptr, "too many profiles"); 1380 return; 1381 } 1382 1383 (void)png_colorspace_set_sRGB(png_ptr, &png_ptr->colorspace, intent); 1384 png_colorspace_sync(png_ptr, info_ptr); 1385 } 1386 #endif /* READ_sRGB */ 1387 1388 #ifdef PNG_READ_iCCP_SUPPORTED 1389 void /* PRIVATE */ 1390 png_handle_iCCP(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 1391 /* Note: this does not properly handle profiles that are > 64K under DOS */ 1392 { 1393 png_const_charp errmsg = NULL; /* error message output, or no error */ 1394 int finished = 0; /* crc checked */ 1395 1396 png_debug(1, "in png_handle_iCCP"); 1397 1398 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 1399 png_chunk_error(png_ptr, "missing IHDR"); 1400 1401 else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0) 1402 { 1403 png_crc_finish(png_ptr, length); 1404 png_chunk_benign_error(png_ptr, "out of place"); 1405 return; 1406 } 1407 1408 /* Consistent with all the above colorspace handling an obviously *invalid* 1409 * chunk is just ignored, so does not invalidate the color space. An 1410 * alternative is to set the 'invalid' flags at the start of this routine 1411 * and only clear them in they were not set before and all the tests pass. 1412 */ 1413 1414 /* The keyword must be at least one character and there is a 1415 * terminator (0) byte and the compression method byte, and the 1416 * 'zlib' datastream is at least 11 bytes. 1417 */ 1418 if (length < 14) 1419 { 1420 png_crc_finish(png_ptr, length); 1421 png_chunk_benign_error(png_ptr, "too short"); 1422 return; 1423 } 1424 1425 /* If a colorspace error has already been output skip this chunk */ 1426 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0) 1427 { 1428 png_crc_finish(png_ptr, length); 1429 return; 1430 } 1431 1432 /* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect 1433 * this. 1434 */ 1435 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_INTENT) == 0) 1436 { 1437 uInt read_length, keyword_length; 1438 char keyword[81]; 1439 1440 /* Find the keyword; the keyword plus separator and compression method 1441 * bytes can be at most 81 characters long. 1442 */ 1443 read_length = 81; /* maximum */ 1444 if (read_length > length) 1445 read_length = (uInt)length; 1446 1447 png_crc_read(png_ptr, (png_bytep)keyword, read_length); 1448 length -= read_length; 1449 1450 /* The minimum 'zlib' stream is assumed to be just the 2 byte header, 1451 * 5 bytes minimum 'deflate' stream, and the 4 byte checksum. 1452 */ 1453 if (length < 11) 1454 { 1455 png_crc_finish(png_ptr, length); 1456 png_chunk_benign_error(png_ptr, "too short"); 1457 return; 1458 } 1459 1460 keyword_length = 0; 1461 while (keyword_length < 80 && keyword_length < read_length && 1462 keyword[keyword_length] != 0) 1463 ++keyword_length; 1464 1465 /* TODO: make the keyword checking common */ 1466 if (keyword_length >= 1 && keyword_length <= 79) 1467 { 1468 /* We only understand '0' compression - deflate - so if we get a 1469 * different value we can't safely decode the chunk. 1470 */ 1471 if (keyword_length+1 < read_length && 1472 keyword[keyword_length+1] == PNG_COMPRESSION_TYPE_BASE) 1473 { 1474 read_length -= keyword_length+2; 1475 1476 if (png_inflate_claim(png_ptr, png_iCCP) == Z_OK) 1477 { 1478 Byte profile_header[132]={0}; 1479 Byte local_buffer[PNG_INFLATE_BUF_SIZE]; 1480 png_alloc_size_t size = (sizeof profile_header); 1481 1482 png_ptr->zstream.next_in = (Bytef*)keyword + (keyword_length+2); 1483 png_ptr->zstream.avail_in = read_length; 1484 (void)png_inflate_read(png_ptr, local_buffer, 1485 (sizeof local_buffer), &length, profile_header, &size, 1486 0/*finish: don't, because the output is too small*/); 1487 1488 if (size == 0) 1489 { 1490 /* We have the ICC profile header; do the basic header checks. 1491 */ 1492 const png_uint_32 profile_length = 1493 png_get_uint_32(profile_header); 1494 1495 if (png_icc_check_length(png_ptr, &png_ptr->colorspace, 1496 keyword, profile_length) != 0) 1497 { 1498 /* The length is apparently ok, so we can check the 132 1499 * byte header. 1500 */ 1501 if (png_icc_check_header(png_ptr, &png_ptr->colorspace, 1502 keyword, profile_length, profile_header, 1503 png_ptr->color_type) != 0) 1504 { 1505 /* Now read the tag table; a variable size buffer is 1506 * needed at this point, allocate one for the whole 1507 * profile. The header check has already validated 1508 * that none of this stuff will overflow. 1509 */ 1510 const png_uint_32 tag_count = png_get_uint_32( 1511 profile_header+128); 1512 png_bytep profile = png_read_buffer(png_ptr, 1513 profile_length, 2/*silent*/); 1514 1515 if (profile != NULL) 1516 { 1517 memcpy(profile, profile_header, 1518 (sizeof profile_header)); 1519 1520 size = 12 * tag_count; 1521 1522 (void)png_inflate_read(png_ptr, local_buffer, 1523 (sizeof local_buffer), &length, 1524 profile + (sizeof profile_header), &size, 0); 1525 1526 /* Still expect a buffer error because we expect 1527 * there to be some tag data! 1528 */ 1529 if (size == 0) 1530 { 1531 if (png_icc_check_tag_table(png_ptr, 1532 &png_ptr->colorspace, keyword, profile_length, 1533 profile) != 0) 1534 { 1535 /* The profile has been validated for basic 1536 * security issues, so read the whole thing in. 1537 */ 1538 size = profile_length - (sizeof profile_header) 1539 - 12 * tag_count; 1540 1541 (void)png_inflate_read(png_ptr, local_buffer, 1542 (sizeof local_buffer), &length, 1543 profile + (sizeof profile_header) + 1544 12 * tag_count, &size, 1/*finish*/); 1545 1546 if (length > 0 && !(png_ptr->flags & 1547 PNG_FLAG_BENIGN_ERRORS_WARN)) 1548 errmsg = "extra compressed data"; 1549 1550 /* But otherwise allow extra data: */ 1551 else if (size == 0) 1552 { 1553 if (length > 0) 1554 { 1555 /* This can be handled completely, so 1556 * keep going. 1557 */ 1558 png_chunk_warning(png_ptr, 1559 "extra compressed data"); 1560 } 1561 1562 png_crc_finish(png_ptr, length); 1563 finished = 1; 1564 1565 # if defined(PNG_sRGB_SUPPORTED) && PNG_sRGB_PROFILE_CHECKS >= 0 1566 /* Check for a match against sRGB */ 1567 png_icc_set_sRGB(png_ptr, 1568 &png_ptr->colorspace, profile, 1569 png_ptr->zstream.adler); 1570 # endif 1571 1572 /* Steal the profile for info_ptr. */ 1573 if (info_ptr != NULL) 1574 { 1575 png_free_data(png_ptr, info_ptr, 1576 PNG_FREE_ICCP, 0); 1577 1578 info_ptr->iccp_name = png_voidcast(char*, 1579 png_malloc_base(png_ptr, 1580 keyword_length+1)); 1581 if (info_ptr->iccp_name != NULL) 1582 { 1583 memcpy(info_ptr->iccp_name, keyword, 1584 keyword_length+1); 1585 info_ptr->iccp_proflen = 1586 profile_length; 1587 info_ptr->iccp_profile = profile; 1588 png_ptr->read_buffer = NULL; /*steal*/ 1589 info_ptr->free_me |= PNG_FREE_ICCP; 1590 info_ptr->valid |= PNG_INFO_iCCP; 1591 } 1592 1593 else 1594 { 1595 png_ptr->colorspace.flags |= 1596 PNG_COLORSPACE_INVALID; 1597 errmsg = "out of memory"; 1598 } 1599 } 1600 1601 /* else the profile remains in the read 1602 * buffer which gets reused for subsequent 1603 * chunks. 1604 */ 1605 1606 if (info_ptr != NULL) 1607 png_colorspace_sync(png_ptr, info_ptr); 1608 1609 if (errmsg == NULL) 1610 { 1611 png_ptr->zowner = 0; 1612 return; 1613 } 1614 } 1615 if (errmsg == NULL) 1616 errmsg = png_ptr->zstream.msg; 1617 } 1618 /* else png_icc_check_tag_table output an error */ 1619 } 1620 else /* profile truncated */ 1621 errmsg = png_ptr->zstream.msg; 1622 } 1623 1624 else 1625 errmsg = "out of memory"; 1626 } 1627 1628 /* else png_icc_check_header output an error */ 1629 } 1630 1631 /* else png_icc_check_length output an error */ 1632 } 1633 1634 else /* profile truncated */ 1635 errmsg = png_ptr->zstream.msg; 1636 1637 /* Release the stream */ 1638 png_ptr->zowner = 0; 1639 } 1640 1641 else /* png_inflate_claim failed */ 1642 errmsg = png_ptr->zstream.msg; 1643 } 1644 1645 else 1646 errmsg = "bad compression method"; /* or missing */ 1647 } 1648 1649 else 1650 errmsg = "bad keyword"; 1651 } 1652 1653 else 1654 errmsg = "too many profiles"; 1655 1656 /* Failure: the reason is in 'errmsg' */ 1657 if (finished == 0) 1658 png_crc_finish(png_ptr, length); 1659 1660 png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID; 1661 png_colorspace_sync(png_ptr, info_ptr); 1662 if (errmsg != NULL) /* else already output */ 1663 png_chunk_benign_error(png_ptr, errmsg); 1664 } 1665 #endif /* READ_iCCP */ 1666 1667 #ifdef PNG_READ_sPLT_SUPPORTED 1668 void /* PRIVATE */ 1669 png_handle_sPLT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 1670 /* Note: this does not properly handle chunks that are > 64K under DOS */ 1671 { 1672 png_bytep entry_start, buffer; 1673 png_sPLT_t new_palette; 1674 png_sPLT_entryp pp; 1675 png_uint_32 data_length; 1676 int entry_size, i; 1677 png_uint_32 skip = 0; 1678 png_uint_32 dl; 1679 size_t max_dl; 1680 1681 png_debug(1, "in png_handle_sPLT"); 1682 1683 #ifdef PNG_USER_LIMITS_SUPPORTED 1684 if (png_ptr->user_chunk_cache_max != 0) 1685 { 1686 if (png_ptr->user_chunk_cache_max == 1) 1687 { 1688 png_crc_finish(png_ptr, length); 1689 return; 1690 } 1691 1692 if (--png_ptr->user_chunk_cache_max == 1) 1693 { 1694 png_warning(png_ptr, "No space in chunk cache for sPLT"); 1695 png_crc_finish(png_ptr, length); 1696 return; 1697 } 1698 } 1699 #endif 1700 1701 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 1702 png_chunk_error(png_ptr, "missing IHDR"); 1703 1704 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) 1705 { 1706 png_crc_finish(png_ptr, length); 1707 png_chunk_benign_error(png_ptr, "out of place"); 1708 return; 1709 } 1710 1711 #ifdef PNG_MAX_MALLOC_64K 1712 if (length > 65535U) 1713 { 1714 png_crc_finish(png_ptr, length); 1715 png_chunk_benign_error(png_ptr, "too large to fit in memory"); 1716 return; 1717 } 1718 #endif 1719 1720 buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/); 1721 if (buffer == NULL) 1722 { 1723 png_crc_finish(png_ptr, length); 1724 png_chunk_benign_error(png_ptr, "out of memory"); 1725 return; 1726 } 1727 1728 1729 /* WARNING: this may break if size_t is less than 32 bits; it is assumed 1730 * that the PNG_MAX_MALLOC_64K test is enabled in this case, but this is a 1731 * potential breakage point if the types in pngconf.h aren't exactly right. 1732 */ 1733 png_crc_read(png_ptr, buffer, length); 1734 1735 if (png_crc_finish(png_ptr, skip) != 0) 1736 return; 1737 1738 buffer[length] = 0; 1739 1740 for (entry_start = buffer; *entry_start; entry_start++) 1741 /* Empty loop to find end of name */ ; 1742 1743 ++entry_start; 1744 1745 /* A sample depth should follow the separator, and we should be on it */ 1746 if (length < 2U || entry_start > buffer + (length - 2U)) 1747 { 1748 png_warning(png_ptr, "malformed sPLT chunk"); 1749 return; 1750 } 1751 1752 new_palette.depth = *entry_start++; 1753 entry_size = (new_palette.depth == 8 ? 6 : 10); 1754 /* This must fit in a png_uint_32 because it is derived from the original 1755 * chunk data length. 1756 */ 1757 data_length = length - (png_uint_32)(entry_start - buffer); 1758 1759 /* Integrity-check the data length */ 1760 if ((data_length % (unsigned int)entry_size) != 0) 1761 { 1762 png_warning(png_ptr, "sPLT chunk has bad length"); 1763 return; 1764 } 1765 1766 dl = (png_uint_32)(data_length / (unsigned int)entry_size); 1767 max_dl = PNG_SIZE_MAX / (sizeof (png_sPLT_entry)); 1768 1769 if (dl > max_dl) 1770 { 1771 png_warning(png_ptr, "sPLT chunk too long"); 1772 return; 1773 } 1774 1775 new_palette.nentries = (png_int_32)(data_length / (unsigned int)entry_size); 1776 1777 new_palette.entries = (png_sPLT_entryp)png_malloc_warn(png_ptr, 1778 (png_alloc_size_t) new_palette.nentries * (sizeof (png_sPLT_entry))); 1779 1780 if (new_palette.entries == NULL) 1781 { 1782 png_warning(png_ptr, "sPLT chunk requires too much memory"); 1783 return; 1784 } 1785 1786 #ifdef PNG_POINTER_INDEXING_SUPPORTED 1787 for (i = 0; i < new_palette.nentries; i++) 1788 { 1789 pp = new_palette.entries + i; 1790 1791 if (new_palette.depth == 8) 1792 { 1793 pp->red = *entry_start++; 1794 pp->green = *entry_start++; 1795 pp->blue = *entry_start++; 1796 pp->alpha = *entry_start++; 1797 } 1798 1799 else 1800 { 1801 pp->red = png_get_uint_16(entry_start); entry_start += 2; 1802 pp->green = png_get_uint_16(entry_start); entry_start += 2; 1803 pp->blue = png_get_uint_16(entry_start); entry_start += 2; 1804 pp->alpha = png_get_uint_16(entry_start); entry_start += 2; 1805 } 1806 1807 pp->frequency = png_get_uint_16(entry_start); entry_start += 2; 1808 } 1809 #else 1810 pp = new_palette.entries; 1811 1812 for (i = 0; i < new_palette.nentries; i++) 1813 { 1814 1815 if (new_palette.depth == 8) 1816 { 1817 pp[i].red = *entry_start++; 1818 pp[i].green = *entry_start++; 1819 pp[i].blue = *entry_start++; 1820 pp[i].alpha = *entry_start++; 1821 } 1822 1823 else 1824 { 1825 pp[i].red = png_get_uint_16(entry_start); entry_start += 2; 1826 pp[i].green = png_get_uint_16(entry_start); entry_start += 2; 1827 pp[i].blue = png_get_uint_16(entry_start); entry_start += 2; 1828 pp[i].alpha = png_get_uint_16(entry_start); entry_start += 2; 1829 } 1830 1831 pp[i].frequency = png_get_uint_16(entry_start); entry_start += 2; 1832 } 1833 #endif 1834 1835 /* Discard all chunk data except the name and stash that */ 1836 new_palette.name = (png_charp)buffer; 1837 1838 png_set_sPLT(png_ptr, info_ptr, &new_palette, 1); 1839 1840 png_free(png_ptr, new_palette.entries); 1841 } 1842 #endif /* READ_sPLT */ 1843 1844 #ifdef PNG_READ_tRNS_SUPPORTED 1845 void /* PRIVATE */ 1846 png_handle_tRNS(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 1847 { 1848 png_byte readbuf[PNG_MAX_PALETTE_LENGTH]; 1849 1850 png_debug(1, "in png_handle_tRNS"); 1851 1852 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 1853 png_chunk_error(png_ptr, "missing IHDR"); 1854 1855 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) 1856 { 1857 png_crc_finish(png_ptr, length); 1858 png_chunk_benign_error(png_ptr, "out of place"); 1859 return; 1860 } 1861 1862 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS) != 0) 1863 { 1864 png_crc_finish(png_ptr, length); 1865 png_chunk_benign_error(png_ptr, "duplicate"); 1866 return; 1867 } 1868 1869 if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY) 1870 { 1871 png_byte buf[2]; 1872 1873 if (length != 2) 1874 { 1875 png_crc_finish(png_ptr, length); 1876 png_chunk_benign_error(png_ptr, "invalid"); 1877 return; 1878 } 1879 1880 png_crc_read(png_ptr, buf, 2); 1881 png_ptr->num_trans = 1; 1882 png_ptr->trans_color.gray = png_get_uint_16(buf); 1883 } 1884 1885 else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB) 1886 { 1887 png_byte buf[6]; 1888 1889 if (length != 6) 1890 { 1891 png_crc_finish(png_ptr, length); 1892 png_chunk_benign_error(png_ptr, "invalid"); 1893 return; 1894 } 1895 1896 png_crc_read(png_ptr, buf, length); 1897 png_ptr->num_trans = 1; 1898 png_ptr->trans_color.red = png_get_uint_16(buf); 1899 png_ptr->trans_color.green = png_get_uint_16(buf + 2); 1900 png_ptr->trans_color.blue = png_get_uint_16(buf + 4); 1901 } 1902 1903 else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) 1904 { 1905 if ((png_ptr->mode & PNG_HAVE_PLTE) == 0) 1906 { 1907 /* TODO: is this actually an error in the ISO spec? */ 1908 png_crc_finish(png_ptr, length); 1909 png_chunk_benign_error(png_ptr, "out of place"); 1910 return; 1911 } 1912 1913 if (length > (unsigned int) png_ptr->num_palette || 1914 length > (unsigned int) PNG_MAX_PALETTE_LENGTH || 1915 length == 0) 1916 { 1917 png_crc_finish(png_ptr, length); 1918 png_chunk_benign_error(png_ptr, "invalid"); 1919 return; 1920 } 1921 1922 png_crc_read(png_ptr, readbuf, length); 1923 png_ptr->num_trans = (png_uint_16)length; 1924 } 1925 1926 else 1927 { 1928 png_crc_finish(png_ptr, length); 1929 png_chunk_benign_error(png_ptr, "invalid with alpha channel"); 1930 return; 1931 } 1932 1933 if (png_crc_finish(png_ptr, 0) != 0) 1934 { 1935 png_ptr->num_trans = 0; 1936 return; 1937 } 1938 1939 /* TODO: this is a horrible side effect in the palette case because the 1940 * png_struct ends up with a pointer to the tRNS buffer owned by the 1941 * png_info. Fix this. 1942 */ 1943 png_set_tRNS(png_ptr, info_ptr, readbuf, png_ptr->num_trans, 1944 &(png_ptr->trans_color)); 1945 } 1946 #endif 1947 1948 #ifdef PNG_READ_bKGD_SUPPORTED 1949 void /* PRIVATE */ 1950 png_handle_bKGD(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 1951 { 1952 unsigned int truelen; 1953 png_byte buf[6]; 1954 png_color_16 background; 1955 1956 png_debug(1, "in png_handle_bKGD"); 1957 1958 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 1959 png_chunk_error(png_ptr, "missing IHDR"); 1960 1961 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0 || 1962 (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE && 1963 (png_ptr->mode & PNG_HAVE_PLTE) == 0)) 1964 { 1965 png_crc_finish(png_ptr, length); 1966 png_chunk_benign_error(png_ptr, "out of place"); 1967 return; 1968 } 1969 1970 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD) != 0) 1971 { 1972 png_crc_finish(png_ptr, length); 1973 png_chunk_benign_error(png_ptr, "duplicate"); 1974 return; 1975 } 1976 1977 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) 1978 truelen = 1; 1979 1980 else if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0) 1981 truelen = 6; 1982 1983 else 1984 truelen = 2; 1985 1986 if (length != truelen) 1987 { 1988 png_crc_finish(png_ptr, length); 1989 png_chunk_benign_error(png_ptr, "invalid"); 1990 return; 1991 } 1992 1993 png_crc_read(png_ptr, buf, truelen); 1994 1995 if (png_crc_finish(png_ptr, 0) != 0) 1996 return; 1997 1998 /* We convert the index value into RGB components so that we can allow 1999 * arbitrary RGB values for background when we have transparency, and 2000 * so it is easy to determine the RGB values of the background color 2001 * from the info_ptr struct. 2002 */ 2003 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) 2004 { 2005 background.index = buf[0]; 2006 2007 if (info_ptr != NULL && info_ptr->num_palette != 0) 2008 { 2009 if (buf[0] >= info_ptr->num_palette) 2010 { 2011 png_chunk_benign_error(png_ptr, "invalid index"); 2012 return; 2013 } 2014 2015 background.red = (png_uint_16)png_ptr->palette[buf[0]].red; 2016 background.green = (png_uint_16)png_ptr->palette[buf[0]].green; 2017 background.blue = (png_uint_16)png_ptr->palette[buf[0]].blue; 2018 } 2019 2020 else 2021 background.red = background.green = background.blue = 0; 2022 2023 background.gray = 0; 2024 } 2025 2026 else if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0) /* GRAY */ 2027 { 2028 if (png_ptr->bit_depth <= 8) 2029 { 2030 if (buf[0] != 0 || buf[1] >= (unsigned int)(1 << png_ptr->bit_depth)) 2031 { 2032 png_chunk_benign_error(png_ptr, "invalid gray level"); 2033 return; 2034 } 2035 } 2036 2037 background.index = 0; 2038 background.red = 2039 background.green = 2040 background.blue = 2041 background.gray = png_get_uint_16(buf); 2042 } 2043 2044 else 2045 { 2046 if (png_ptr->bit_depth <= 8) 2047 { 2048 if (buf[0] != 0 || buf[2] != 0 || buf[4] != 0) 2049 { 2050 png_chunk_benign_error(png_ptr, "invalid color"); 2051 return; 2052 } 2053 } 2054 2055 background.index = 0; 2056 background.red = png_get_uint_16(buf); 2057 background.green = png_get_uint_16(buf + 2); 2058 background.blue = png_get_uint_16(buf + 4); 2059 background.gray = 0; 2060 } 2061 2062 png_set_bKGD(png_ptr, info_ptr, &background); 2063 } 2064 #endif 2065 2066 #ifdef PNG_READ_eXIf_SUPPORTED 2067 void /* PRIVATE */ 2068 png_handle_eXIf(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 2069 { 2070 unsigned int i; 2071 2072 png_debug(1, "in png_handle_eXIf"); 2073 2074 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 2075 png_chunk_error(png_ptr, "missing IHDR"); 2076 2077 if (length < 2) 2078 { 2079 png_crc_finish(png_ptr, length); 2080 png_chunk_benign_error(png_ptr, "too short"); 2081 return; 2082 } 2083 2084 else if (info_ptr == NULL || (info_ptr->valid & PNG_INFO_eXIf) != 0) 2085 { 2086 png_crc_finish(png_ptr, length); 2087 png_chunk_benign_error(png_ptr, "duplicate"); 2088 return; 2089 } 2090 2091 info_ptr->free_me |= PNG_FREE_EXIF; 2092 2093 info_ptr->eXIf_buf = png_voidcast(png_bytep, 2094 png_malloc_warn(png_ptr, length)); 2095 2096 if (info_ptr->eXIf_buf == NULL) 2097 { 2098 png_crc_finish(png_ptr, length); 2099 png_chunk_benign_error(png_ptr, "out of memory"); 2100 return; 2101 } 2102 2103 for (i = 0; i < length; i++) 2104 { 2105 png_byte buf[1]; 2106 png_crc_read(png_ptr, buf, 1); 2107 info_ptr->eXIf_buf[i] = buf[0]; 2108 if (i == 1 && buf[0] != 'M' && buf[0] != 'I' 2109 && info_ptr->eXIf_buf[0] != buf[0]) 2110 { 2111 png_crc_finish(png_ptr, length); 2112 png_chunk_benign_error(png_ptr, "incorrect byte-order specifier"); 2113 png_free(png_ptr, info_ptr->eXIf_buf); 2114 info_ptr->eXIf_buf = NULL; 2115 return; 2116 } 2117 } 2118 2119 if (png_crc_finish(png_ptr, 0) != 0) 2120 return; 2121 2122 png_set_eXIf_1(png_ptr, info_ptr, length, info_ptr->eXIf_buf); 2123 2124 png_free(png_ptr, info_ptr->eXIf_buf); 2125 info_ptr->eXIf_buf = NULL; 2126 } 2127 #endif 2128 2129 #ifdef PNG_READ_hIST_SUPPORTED 2130 void /* PRIVATE */ 2131 png_handle_hIST(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 2132 { 2133 unsigned int num, i; 2134 png_uint_16 readbuf[PNG_MAX_PALETTE_LENGTH]; 2135 2136 png_debug(1, "in png_handle_hIST"); 2137 2138 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 2139 png_chunk_error(png_ptr, "missing IHDR"); 2140 2141 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0 || 2142 (png_ptr->mode & PNG_HAVE_PLTE) == 0) 2143 { 2144 png_crc_finish(png_ptr, length); 2145 png_chunk_benign_error(png_ptr, "out of place"); 2146 return; 2147 } 2148 2149 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST) != 0) 2150 { 2151 png_crc_finish(png_ptr, length); 2152 png_chunk_benign_error(png_ptr, "duplicate"); 2153 return; 2154 } 2155 2156 num = length / 2 ; 2157 2158 if (num != (unsigned int) png_ptr->num_palette || 2159 num > (unsigned int) PNG_MAX_PALETTE_LENGTH) 2160 { 2161 png_crc_finish(png_ptr, length); 2162 png_chunk_benign_error(png_ptr, "invalid"); 2163 return; 2164 } 2165 2166 for (i = 0; i < num; i++) 2167 { 2168 png_byte buf[2]; 2169 2170 png_crc_read(png_ptr, buf, 2); 2171 readbuf[i] = png_get_uint_16(buf); 2172 } 2173 2174 if (png_crc_finish(png_ptr, 0) != 0) 2175 return; 2176 2177 png_set_hIST(png_ptr, info_ptr, readbuf); 2178 } 2179 #endif 2180 2181 #ifdef PNG_READ_pHYs_SUPPORTED 2182 void /* PRIVATE */ 2183 png_handle_pHYs(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 2184 { 2185 png_byte buf[9]; 2186 png_uint_32 res_x, res_y; 2187 int unit_type; 2188 2189 png_debug(1, "in png_handle_pHYs"); 2190 2191 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 2192 png_chunk_error(png_ptr, "missing IHDR"); 2193 2194 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) 2195 { 2196 png_crc_finish(png_ptr, length); 2197 png_chunk_benign_error(png_ptr, "out of place"); 2198 return; 2199 } 2200 2201 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs) != 0) 2202 { 2203 png_crc_finish(png_ptr, length); 2204 png_chunk_benign_error(png_ptr, "duplicate"); 2205 return; 2206 } 2207 2208 if (length != 9) 2209 { 2210 png_crc_finish(png_ptr, length); 2211 png_chunk_benign_error(png_ptr, "invalid"); 2212 return; 2213 } 2214 2215 png_crc_read(png_ptr, buf, 9); 2216 2217 if (png_crc_finish(png_ptr, 0) != 0) 2218 return; 2219 2220 res_x = png_get_uint_32(buf); 2221 res_y = png_get_uint_32(buf + 4); 2222 unit_type = buf[8]; 2223 png_set_pHYs(png_ptr, info_ptr, res_x, res_y, unit_type); 2224 } 2225 #endif 2226 2227 #ifdef PNG_READ_oFFs_SUPPORTED 2228 void /* PRIVATE */ 2229 png_handle_oFFs(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 2230 { 2231 png_byte buf[9]; 2232 png_int_32 offset_x, offset_y; 2233 int unit_type; 2234 2235 png_debug(1, "in png_handle_oFFs"); 2236 2237 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 2238 png_chunk_error(png_ptr, "missing IHDR"); 2239 2240 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) 2241 { 2242 png_crc_finish(png_ptr, length); 2243 png_chunk_benign_error(png_ptr, "out of place"); 2244 return; 2245 } 2246 2247 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs) != 0) 2248 { 2249 png_crc_finish(png_ptr, length); 2250 png_chunk_benign_error(png_ptr, "duplicate"); 2251 return; 2252 } 2253 2254 if (length != 9) 2255 { 2256 png_crc_finish(png_ptr, length); 2257 png_chunk_benign_error(png_ptr, "invalid"); 2258 return; 2259 } 2260 2261 png_crc_read(png_ptr, buf, 9); 2262 2263 if (png_crc_finish(png_ptr, 0) != 0) 2264 return; 2265 2266 offset_x = png_get_int_32(buf); 2267 offset_y = png_get_int_32(buf + 4); 2268 unit_type = buf[8]; 2269 png_set_oFFs(png_ptr, info_ptr, offset_x, offset_y, unit_type); 2270 } 2271 #endif 2272 2273 #ifdef PNG_READ_pCAL_SUPPORTED 2274 /* Read the pCAL chunk (described in the PNG Extensions document) */ 2275 void /* PRIVATE */ 2276 png_handle_pCAL(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 2277 { 2278 png_int_32 X0, X1; 2279 png_byte type, nparams; 2280 png_bytep buffer, buf, units, endptr; 2281 png_charpp params; 2282 int i; 2283 2284 png_debug(1, "in png_handle_pCAL"); 2285 2286 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 2287 png_chunk_error(png_ptr, "missing IHDR"); 2288 2289 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) 2290 { 2291 png_crc_finish(png_ptr, length); 2292 png_chunk_benign_error(png_ptr, "out of place"); 2293 return; 2294 } 2295 2296 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pCAL) != 0) 2297 { 2298 png_crc_finish(png_ptr, length); 2299 png_chunk_benign_error(png_ptr, "duplicate"); 2300 return; 2301 } 2302 2303 png_debug1(2, "Allocating and reading pCAL chunk data (%u bytes)", 2304 length + 1); 2305 2306 buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/); 2307 2308 if (buffer == NULL) 2309 { 2310 png_crc_finish(png_ptr, length); 2311 png_chunk_benign_error(png_ptr, "out of memory"); 2312 return; 2313 } 2314 2315 png_crc_read(png_ptr, buffer, length); 2316 2317 if (png_crc_finish(png_ptr, 0) != 0) 2318 return; 2319 2320 buffer[length] = 0; /* Null terminate the last string */ 2321 2322 png_debug(3, "Finding end of pCAL purpose string"); 2323 for (buf = buffer; *buf; buf++) 2324 /* Empty loop */ ; 2325 2326 endptr = buffer + length; 2327 2328 /* We need to have at least 12 bytes after the purpose string 2329 * in order to get the parameter information. 2330 */ 2331 if (endptr - buf <= 12) 2332 { 2333 png_chunk_benign_error(png_ptr, "invalid"); 2334 return; 2335 } 2336 2337 png_debug(3, "Reading pCAL X0, X1, type, nparams, and units"); 2338 X0 = png_get_int_32((png_bytep)buf+1); 2339 X1 = png_get_int_32((png_bytep)buf+5); 2340 type = buf[9]; 2341 nparams = buf[10]; 2342 units = buf + 11; 2343 2344 png_debug(3, "Checking pCAL equation type and number of parameters"); 2345 /* Check that we have the right number of parameters for known 2346 * equation types. 2347 */ 2348 if ((type == PNG_EQUATION_LINEAR && nparams != 2) || 2349 (type == PNG_EQUATION_BASE_E && nparams != 3) || 2350 (type == PNG_EQUATION_ARBITRARY && nparams != 3) || 2351 (type == PNG_EQUATION_HYPERBOLIC && nparams != 4)) 2352 { 2353 png_chunk_benign_error(png_ptr, "invalid parameter count"); 2354 return; 2355 } 2356 2357 else if (type >= PNG_EQUATION_LAST) 2358 { 2359 png_chunk_benign_error(png_ptr, "unrecognized equation type"); 2360 } 2361 2362 for (buf = units; *buf; buf++) 2363 /* Empty loop to move past the units string. */ ; 2364 2365 png_debug(3, "Allocating pCAL parameters array"); 2366 2367 params = png_voidcast(png_charpp, png_malloc_warn(png_ptr, 2368 nparams * (sizeof (png_charp)))); 2369 2370 if (params == NULL) 2371 { 2372 png_chunk_benign_error(png_ptr, "out of memory"); 2373 return; 2374 } 2375 2376 /* Get pointers to the start of each parameter string. */ 2377 for (i = 0; i < nparams; i++) 2378 { 2379 buf++; /* Skip the null string terminator from previous parameter. */ 2380 2381 png_debug1(3, "Reading pCAL parameter %d", i); 2382 2383 for (params[i] = (png_charp)buf; buf <= endptr && *buf != 0; buf++) 2384 /* Empty loop to move past each parameter string */ ; 2385 2386 /* Make sure we haven't run out of data yet */ 2387 if (buf > endptr) 2388 { 2389 png_free(png_ptr, params); 2390 png_chunk_benign_error(png_ptr, "invalid data"); 2391 return; 2392 } 2393 } 2394 2395 png_set_pCAL(png_ptr, info_ptr, (png_charp)buffer, X0, X1, type, nparams, 2396 (png_charp)units, params); 2397 2398 png_free(png_ptr, params); 2399 } 2400 #endif 2401 2402 #ifdef PNG_READ_sCAL_SUPPORTED 2403 /* Read the sCAL chunk */ 2404 void /* PRIVATE */ 2405 png_handle_sCAL(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 2406 { 2407 png_bytep buffer; 2408 size_t i; 2409 int state; 2410 2411 png_debug(1, "in png_handle_sCAL"); 2412 2413 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 2414 png_chunk_error(png_ptr, "missing IHDR"); 2415 2416 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) 2417 { 2418 png_crc_finish(png_ptr, length); 2419 png_chunk_benign_error(png_ptr, "out of place"); 2420 return; 2421 } 2422 2423 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sCAL) != 0) 2424 { 2425 png_crc_finish(png_ptr, length); 2426 png_chunk_benign_error(png_ptr, "duplicate"); 2427 return; 2428 } 2429 2430 /* Need unit type, width, \0, height: minimum 4 bytes */ 2431 else if (length < 4) 2432 { 2433 png_crc_finish(png_ptr, length); 2434 png_chunk_benign_error(png_ptr, "invalid"); 2435 return; 2436 } 2437 2438 png_debug1(2, "Allocating and reading sCAL chunk data (%u bytes)", 2439 length + 1); 2440 2441 buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/); 2442 2443 if (buffer == NULL) 2444 { 2445 png_chunk_benign_error(png_ptr, "out of memory"); 2446 png_crc_finish(png_ptr, length); 2447 return; 2448 } 2449 2450 png_crc_read(png_ptr, buffer, length); 2451 buffer[length] = 0; /* Null terminate the last string */ 2452 2453 if (png_crc_finish(png_ptr, 0) != 0) 2454 return; 2455 2456 /* Validate the unit. */ 2457 if (buffer[0] != 1 && buffer[0] != 2) 2458 { 2459 png_chunk_benign_error(png_ptr, "invalid unit"); 2460 return; 2461 } 2462 2463 /* Validate the ASCII numbers, need two ASCII numbers separated by 2464 * a '\0' and they need to fit exactly in the chunk data. 2465 */ 2466 i = 1; 2467 state = 0; 2468 2469 if (png_check_fp_number((png_const_charp)buffer, length, &state, &i) == 0 || 2470 i >= length || buffer[i++] != 0) 2471 png_chunk_benign_error(png_ptr, "bad width format"); 2472 2473 else if (PNG_FP_IS_POSITIVE(state) == 0) 2474 png_chunk_benign_error(png_ptr, "non-positive width"); 2475 2476 else 2477 { 2478 size_t heighti = i; 2479 2480 state = 0; 2481 if (png_check_fp_number((png_const_charp)buffer, length, 2482 &state, &i) == 0 || i != length) 2483 png_chunk_benign_error(png_ptr, "bad height format"); 2484 2485 else if (PNG_FP_IS_POSITIVE(state) == 0) 2486 png_chunk_benign_error(png_ptr, "non-positive height"); 2487 2488 else 2489 /* This is the (only) success case. */ 2490 png_set_sCAL_s(png_ptr, info_ptr, buffer[0], 2491 (png_charp)buffer+1, (png_charp)buffer+heighti); 2492 } 2493 } 2494 #endif 2495 2496 #ifdef PNG_READ_tIME_SUPPORTED 2497 void /* PRIVATE */ 2498 png_handle_tIME(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 2499 { 2500 png_byte buf[7]; 2501 png_time mod_time; 2502 2503 png_debug(1, "in png_handle_tIME"); 2504 2505 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 2506 png_chunk_error(png_ptr, "missing IHDR"); 2507 2508 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tIME) != 0) 2509 { 2510 png_crc_finish(png_ptr, length); 2511 png_chunk_benign_error(png_ptr, "duplicate"); 2512 return; 2513 } 2514 2515 if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) 2516 png_ptr->mode |= PNG_AFTER_IDAT; 2517 2518 if (length != 7) 2519 { 2520 png_crc_finish(png_ptr, length); 2521 png_chunk_benign_error(png_ptr, "invalid"); 2522 return; 2523 } 2524 2525 png_crc_read(png_ptr, buf, 7); 2526 2527 if (png_crc_finish(png_ptr, 0) != 0) 2528 return; 2529 2530 mod_time.second = buf[6]; 2531 mod_time.minute = buf[5]; 2532 mod_time.hour = buf[4]; 2533 mod_time.day = buf[3]; 2534 mod_time.month = buf[2]; 2535 mod_time.year = png_get_uint_16(buf); 2536 2537 png_set_tIME(png_ptr, info_ptr, &mod_time); 2538 } 2539 #endif 2540 2541 #ifdef PNG_READ_tEXt_SUPPORTED 2542 /* Note: this does not properly handle chunks that are > 64K under DOS */ 2543 void /* PRIVATE */ 2544 png_handle_tEXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 2545 { 2546 png_text text_info; 2547 png_bytep buffer; 2548 png_charp key; 2549 png_charp text; 2550 png_uint_32 skip = 0; 2551 2552 png_debug(1, "in png_handle_tEXt"); 2553 2554 #ifdef PNG_USER_LIMITS_SUPPORTED 2555 if (png_ptr->user_chunk_cache_max != 0) 2556 { 2557 if (png_ptr->user_chunk_cache_max == 1) 2558 { 2559 png_crc_finish(png_ptr, length); 2560 return; 2561 } 2562 2563 if (--png_ptr->user_chunk_cache_max == 1) 2564 { 2565 png_crc_finish(png_ptr, length); 2566 png_chunk_benign_error(png_ptr, "no space in chunk cache"); 2567 return; 2568 } 2569 } 2570 #endif 2571 2572 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 2573 png_chunk_error(png_ptr, "missing IHDR"); 2574 2575 if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) 2576 png_ptr->mode |= PNG_AFTER_IDAT; 2577 2578 #ifdef PNG_MAX_MALLOC_64K 2579 if (length > 65535U) 2580 { 2581 png_crc_finish(png_ptr, length); 2582 png_chunk_benign_error(png_ptr, "too large to fit in memory"); 2583 return; 2584 } 2585 #endif 2586 2587 buffer = png_read_buffer(png_ptr, length+1, 1/*warn*/); 2588 2589 if (buffer == NULL) 2590 { 2591 png_chunk_benign_error(png_ptr, "out of memory"); 2592 return; 2593 } 2594 2595 png_crc_read(png_ptr, buffer, length); 2596 2597 if (png_crc_finish(png_ptr, skip) != 0) 2598 return; 2599 2600 key = (png_charp)buffer; 2601 key[length] = 0; 2602 2603 for (text = key; *text; text++) 2604 /* Empty loop to find end of key */ ; 2605 2606 if (text != key + length) 2607 text++; 2608 2609 text_info.compression = PNG_TEXT_COMPRESSION_NONE; 2610 text_info.key = key; 2611 text_info.lang = NULL; 2612 text_info.lang_key = NULL; 2613 text_info.itxt_length = 0; 2614 text_info.text = text; 2615 text_info.text_length = strlen(text); 2616 2617 if (png_set_text_2(png_ptr, info_ptr, &text_info, 1) != 0) 2618 png_warning(png_ptr, "Insufficient memory to process text chunk"); 2619 } 2620 #endif 2621 2622 #ifdef PNG_READ_zTXt_SUPPORTED 2623 /* Note: this does not correctly handle chunks that are > 64K under DOS */ 2624 void /* PRIVATE */ 2625 png_handle_zTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 2626 { 2627 png_const_charp errmsg = NULL; 2628 png_bytep buffer; 2629 png_uint_32 keyword_length; 2630 2631 png_debug(1, "in png_handle_zTXt"); 2632 2633 #ifdef PNG_USER_LIMITS_SUPPORTED 2634 if (png_ptr->user_chunk_cache_max != 0) 2635 { 2636 if (png_ptr->user_chunk_cache_max == 1) 2637 { 2638 png_crc_finish(png_ptr, length); 2639 return; 2640 } 2641 2642 if (--png_ptr->user_chunk_cache_max == 1) 2643 { 2644 png_crc_finish(png_ptr, length); 2645 png_chunk_benign_error(png_ptr, "no space in chunk cache"); 2646 return; 2647 } 2648 } 2649 #endif 2650 2651 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 2652 png_chunk_error(png_ptr, "missing IHDR"); 2653 2654 if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) 2655 png_ptr->mode |= PNG_AFTER_IDAT; 2656 2657 /* Note, "length" is sufficient here; we won't be adding 2658 * a null terminator later. 2659 */ 2660 buffer = png_read_buffer(png_ptr, length, 2/*silent*/); 2661 2662 if (buffer == NULL) 2663 { 2664 png_crc_finish(png_ptr, length); 2665 png_chunk_benign_error(png_ptr, "out of memory"); 2666 return; 2667 } 2668 2669 png_crc_read(png_ptr, buffer, length); 2670 2671 if (png_crc_finish(png_ptr, 0) != 0) 2672 return; 2673 2674 /* TODO: also check that the keyword contents match the spec! */ 2675 for (keyword_length = 0; 2676 keyword_length < length && buffer[keyword_length] != 0; 2677 ++keyword_length) 2678 /* Empty loop to find end of name */ ; 2679 2680 if (keyword_length > 79 || keyword_length < 1) 2681 errmsg = "bad keyword"; 2682 2683 /* zTXt must have some LZ data after the keyword, although it may expand to 2684 * zero bytes; we need a '\0' at the end of the keyword, the compression type 2685 * then the LZ data: 2686 */ 2687 else if (keyword_length + 3 > length) 2688 errmsg = "truncated"; 2689 2690 else if (buffer[keyword_length+1] != PNG_COMPRESSION_TYPE_BASE) 2691 errmsg = "unknown compression type"; 2692 2693 else 2694 { 2695 png_alloc_size_t uncompressed_length = PNG_SIZE_MAX; 2696 2697 /* TODO: at present png_decompress_chunk imposes a single application 2698 * level memory limit, this should be split to different values for iCCP 2699 * and text chunks. 2700 */ 2701 if (png_decompress_chunk(png_ptr, length, keyword_length+2, 2702 &uncompressed_length, 1/*terminate*/) == Z_STREAM_END) 2703 { 2704 png_text text; 2705 2706 if (png_ptr->read_buffer == NULL) 2707 errmsg="Read failure in png_handle_zTXt"; 2708 else 2709 { 2710 /* It worked; png_ptr->read_buffer now looks like a tEXt chunk 2711 * except for the extra compression type byte and the fact that 2712 * it isn't necessarily '\0' terminated. 2713 */ 2714 buffer = png_ptr->read_buffer; 2715 buffer[uncompressed_length+(keyword_length+2)] = 0; 2716 2717 text.compression = PNG_TEXT_COMPRESSION_zTXt; 2718 text.key = (png_charp)buffer; 2719 text.text = (png_charp)(buffer + keyword_length+2); 2720 text.text_length = uncompressed_length; 2721 text.itxt_length = 0; 2722 text.lang = NULL; 2723 text.lang_key = NULL; 2724 2725 if (png_set_text_2(png_ptr, info_ptr, &text, 1) != 0) 2726 errmsg = "insufficient memory"; 2727 } 2728 } 2729 2730 else 2731 errmsg = png_ptr->zstream.msg; 2732 } 2733 2734 if (errmsg != NULL) 2735 png_chunk_benign_error(png_ptr, errmsg); 2736 } 2737 #endif 2738 2739 #ifdef PNG_READ_iTXt_SUPPORTED 2740 /* Note: this does not correctly handle chunks that are > 64K under DOS */ 2741 void /* PRIVATE */ 2742 png_handle_iTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) 2743 { 2744 png_const_charp errmsg = NULL; 2745 png_bytep buffer; 2746 png_uint_32 prefix_length; 2747 2748 png_debug(1, "in png_handle_iTXt"); 2749 2750 #ifdef PNG_USER_LIMITS_SUPPORTED 2751 if (png_ptr->user_chunk_cache_max != 0) 2752 { 2753 if (png_ptr->user_chunk_cache_max == 1) 2754 { 2755 png_crc_finish(png_ptr, length); 2756 return; 2757 } 2758 2759 if (--png_ptr->user_chunk_cache_max == 1) 2760 { 2761 png_crc_finish(png_ptr, length); 2762 png_chunk_benign_error(png_ptr, "no space in chunk cache"); 2763 return; 2764 } 2765 } 2766 #endif 2767 2768 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 2769 png_chunk_error(png_ptr, "missing IHDR"); 2770 2771 if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) 2772 png_ptr->mode |= PNG_AFTER_IDAT; 2773 2774 buffer = png_read_buffer(png_ptr, length+1, 1/*warn*/); 2775 2776 if (buffer == NULL) 2777 { 2778 png_crc_finish(png_ptr, length); 2779 png_chunk_benign_error(png_ptr, "out of memory"); 2780 return; 2781 } 2782 2783 png_crc_read(png_ptr, buffer, length); 2784 2785 if (png_crc_finish(png_ptr, 0) != 0) 2786 return; 2787 2788 /* First the keyword. */ 2789 for (prefix_length=0; 2790 prefix_length < length && buffer[prefix_length] != 0; 2791 ++prefix_length) 2792 /* Empty loop */ ; 2793 2794 /* Perform a basic check on the keyword length here. */ 2795 if (prefix_length > 79 || prefix_length < 1) 2796 errmsg = "bad keyword"; 2797 2798 /* Expect keyword, compression flag, compression type, language, translated 2799 * keyword (both may be empty but are 0 terminated) then the text, which may 2800 * be empty. 2801 */ 2802 else if (prefix_length + 5 > length) 2803 errmsg = "truncated"; 2804 2805 else if (buffer[prefix_length+1] == 0 || 2806 (buffer[prefix_length+1] == 1 && 2807 buffer[prefix_length+2] == PNG_COMPRESSION_TYPE_BASE)) 2808 { 2809 int compressed = buffer[prefix_length+1] != 0; 2810 png_uint_32 language_offset, translated_keyword_offset; 2811 png_alloc_size_t uncompressed_length = 0; 2812 2813 /* Now the language tag */ 2814 prefix_length += 3; 2815 language_offset = prefix_length; 2816 2817 for (; prefix_length < length && buffer[prefix_length] != 0; 2818 ++prefix_length) 2819 /* Empty loop */ ; 2820 2821 /* WARNING: the length may be invalid here, this is checked below. */ 2822 translated_keyword_offset = ++prefix_length; 2823 2824 for (; prefix_length < length && buffer[prefix_length] != 0; 2825 ++prefix_length) 2826 /* Empty loop */ ; 2827 2828 /* prefix_length should now be at the trailing '\0' of the translated 2829 * keyword, but it may already be over the end. None of this arithmetic 2830 * can overflow because chunks are at most 2^31 bytes long, but on 16-bit 2831 * systems the available allocation may overflow. 2832 */ 2833 ++prefix_length; 2834 2835 if (compressed == 0 && prefix_length <= length) 2836 uncompressed_length = length - prefix_length; 2837 2838 else if (compressed != 0 && prefix_length < length) 2839 { 2840 uncompressed_length = PNG_SIZE_MAX; 2841 2842 /* TODO: at present png_decompress_chunk imposes a single application 2843 * level memory limit, this should be split to different values for 2844 * iCCP and text chunks. 2845 */ 2846 if (png_decompress_chunk(png_ptr, length, prefix_length, 2847 &uncompressed_length, 1/*terminate*/) == Z_STREAM_END) 2848 buffer = png_ptr->read_buffer; 2849 2850 else 2851 errmsg = png_ptr->zstream.msg; 2852 } 2853 2854 else 2855 errmsg = "truncated"; 2856 2857 if (errmsg == NULL) 2858 { 2859 png_text text; 2860 2861 buffer[uncompressed_length+prefix_length] = 0; 2862 2863 if (compressed == 0) 2864 text.compression = PNG_ITXT_COMPRESSION_NONE; 2865 2866 else 2867 text.compression = PNG_ITXT_COMPRESSION_zTXt; 2868 2869 text.key = (png_charp)buffer; 2870 text.lang = (png_charp)buffer + language_offset; 2871 text.lang_key = (png_charp)buffer + translated_keyword_offset; 2872 text.text = (png_charp)buffer + prefix_length; 2873 text.text_length = 0; 2874 text.itxt_length = uncompressed_length; 2875 2876 if (png_set_text_2(png_ptr, info_ptr, &text, 1) != 0) 2877 errmsg = "insufficient memory"; 2878 } 2879 } 2880 2881 else 2882 errmsg = "bad compression info"; 2883 2884 if (errmsg != NULL) 2885 png_chunk_benign_error(png_ptr, errmsg); 2886 } 2887 #endif 2888 2889 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED 2890 /* Utility function for png_handle_unknown; set up png_ptr::unknown_chunk */ 2891 static int 2892 png_cache_unknown_chunk(png_structrp png_ptr, png_uint_32 length) 2893 { 2894 png_alloc_size_t limit = PNG_SIZE_MAX; 2895 2896 if (png_ptr->unknown_chunk.data != NULL) 2897 { 2898 png_free(png_ptr, png_ptr->unknown_chunk.data); 2899 png_ptr->unknown_chunk.data = NULL; 2900 } 2901 2902 # ifdef PNG_SET_USER_LIMITS_SUPPORTED 2903 if (png_ptr->user_chunk_malloc_max > 0 && 2904 png_ptr->user_chunk_malloc_max < limit) 2905 limit = png_ptr->user_chunk_malloc_max; 2906 2907 # elif PNG_USER_CHUNK_MALLOC_MAX > 0 2908 if (PNG_USER_CHUNK_MALLOC_MAX < limit) 2909 limit = PNG_USER_CHUNK_MALLOC_MAX; 2910 # endif 2911 2912 if (length <= limit) 2913 { 2914 PNG_CSTRING_FROM_CHUNK(png_ptr->unknown_chunk.name, png_ptr->chunk_name); 2915 /* The following is safe because of the PNG_SIZE_MAX init above */ 2916 png_ptr->unknown_chunk.size = (size_t)length/*SAFE*/; 2917 /* 'mode' is a flag array, only the bottom four bits matter here */ 2918 png_ptr->unknown_chunk.location = (png_byte)png_ptr->mode/*SAFE*/; 2919 2920 if (length == 0) 2921 png_ptr->unknown_chunk.data = NULL; 2922 2923 else 2924 { 2925 /* Do a 'warn' here - it is handled below. */ 2926 png_ptr->unknown_chunk.data = png_voidcast(png_bytep, 2927 png_malloc_warn(png_ptr, length)); 2928 } 2929 } 2930 2931 if (png_ptr->unknown_chunk.data == NULL && length > 0) 2932 { 2933 /* This is benign because we clean up correctly */ 2934 png_crc_finish(png_ptr, length); 2935 png_chunk_benign_error(png_ptr, "unknown chunk exceeds memory limits"); 2936 return 0; 2937 } 2938 2939 else 2940 { 2941 if (length > 0) 2942 png_crc_read(png_ptr, png_ptr->unknown_chunk.data, length); 2943 png_crc_finish(png_ptr, 0); 2944 return 1; 2945 } 2946 } 2947 #endif /* READ_UNKNOWN_CHUNKS */ 2948 2949 /* Handle an unknown, or known but disabled, chunk */ 2950 void /* PRIVATE */ 2951 png_handle_unknown(png_structrp png_ptr, png_inforp info_ptr, 2952 png_uint_32 length, int keep) 2953 { 2954 int handled = 0; /* the chunk was handled */ 2955 2956 png_debug(1, "in png_handle_unknown"); 2957 2958 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED 2959 /* NOTE: this code is based on the code in libpng-1.4.12 except for fixing 2960 * the bug which meant that setting a non-default behavior for a specific 2961 * chunk would be ignored (the default was always used unless a user 2962 * callback was installed). 2963 * 2964 * 'keep' is the value from the png_chunk_unknown_handling, the setting for 2965 * this specific chunk_name, if PNG_HANDLE_AS_UNKNOWN_SUPPORTED, if not it 2966 * will always be PNG_HANDLE_CHUNK_AS_DEFAULT and it needs to be set here. 2967 * This is just an optimization to avoid multiple calls to the lookup 2968 * function. 2969 */ 2970 # ifndef PNG_HANDLE_AS_UNKNOWN_SUPPORTED 2971 # ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED 2972 keep = png_chunk_unknown_handling(png_ptr, png_ptr->chunk_name); 2973 # endif 2974 # endif 2975 2976 /* One of the following methods will read the chunk or skip it (at least one 2977 * of these is always defined because this is the only way to switch on 2978 * PNG_READ_UNKNOWN_CHUNKS_SUPPORTED) 2979 */ 2980 # ifdef PNG_READ_USER_CHUNKS_SUPPORTED 2981 /* The user callback takes precedence over the chunk keep value, but the 2982 * keep value is still required to validate a save of a critical chunk. 2983 */ 2984 if (png_ptr->read_user_chunk_fn != NULL) 2985 { 2986 if (png_cache_unknown_chunk(png_ptr, length) != 0) 2987 { 2988 /* Callback to user unknown chunk handler */ 2989 int ret = (*(png_ptr->read_user_chunk_fn))(png_ptr, 2990 &png_ptr->unknown_chunk); 2991 2992 /* ret is: 2993 * negative: An error occurred; png_chunk_error will be called. 2994 * zero: The chunk was not handled, the chunk will be discarded 2995 * unless png_set_keep_unknown_chunks has been used to set 2996 * a 'keep' behavior for this particular chunk, in which 2997 * case that will be used. A critical chunk will cause an 2998 * error at this point unless it is to be saved. 2999 * positive: The chunk was handled, libpng will ignore/discard it. 3000 */ 3001 if (ret < 0) 3002 png_chunk_error(png_ptr, "error in user chunk"); 3003 3004 else if (ret == 0) 3005 { 3006 /* If the keep value is 'default' or 'never' override it, but 3007 * still error out on critical chunks unless the keep value is 3008 * 'always' While this is weird it is the behavior in 1.4.12. 3009 * A possible improvement would be to obey the value set for the 3010 * chunk, but this would be an API change that would probably 3011 * damage some applications. 3012 * 3013 * The png_app_warning below catches the case that matters, where 3014 * the application has not set specific save or ignore for this 3015 * chunk or global save or ignore. 3016 */ 3017 if (keep < PNG_HANDLE_CHUNK_IF_SAFE) 3018 { 3019 # ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED 3020 if (png_ptr->unknown_default < PNG_HANDLE_CHUNK_IF_SAFE) 3021 { 3022 png_chunk_warning(png_ptr, "Saving unknown chunk:"); 3023 png_app_warning(png_ptr, 3024 "forcing save of an unhandled chunk;" 3025 " please call png_set_keep_unknown_chunks"); 3026 /* with keep = PNG_HANDLE_CHUNK_IF_SAFE */ 3027 } 3028 # endif 3029 keep = PNG_HANDLE_CHUNK_IF_SAFE; 3030 } 3031 } 3032 3033 else /* chunk was handled */ 3034 { 3035 handled = 1; 3036 /* Critical chunks can be safely discarded at this point. */ 3037 keep = PNG_HANDLE_CHUNK_NEVER; 3038 } 3039 } 3040 3041 else 3042 keep = PNG_HANDLE_CHUNK_NEVER; /* insufficient memory */ 3043 } 3044 3045 else 3046 /* Use the SAVE_UNKNOWN_CHUNKS code or skip the chunk */ 3047 # endif /* READ_USER_CHUNKS */ 3048 3049 # ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED 3050 { 3051 /* keep is currently just the per-chunk setting, if there was no 3052 * setting change it to the global default now (not that this may 3053 * still be AS_DEFAULT) then obtain the cache of the chunk if required, 3054 * if not simply skip the chunk. 3055 */ 3056 if (keep == PNG_HANDLE_CHUNK_AS_DEFAULT) 3057 keep = png_ptr->unknown_default; 3058 3059 if (keep == PNG_HANDLE_CHUNK_ALWAYS || 3060 (keep == PNG_HANDLE_CHUNK_IF_SAFE && 3061 PNG_CHUNK_ANCILLARY(png_ptr->chunk_name))) 3062 { 3063 if (png_cache_unknown_chunk(png_ptr, length) == 0) 3064 keep = PNG_HANDLE_CHUNK_NEVER; 3065 } 3066 3067 else 3068 png_crc_finish(png_ptr, length); 3069 } 3070 # else 3071 # ifndef PNG_READ_USER_CHUNKS_SUPPORTED 3072 # error no method to support READ_UNKNOWN_CHUNKS 3073 # endif 3074 3075 { 3076 /* If here there is no read callback pointer set and no support is 3077 * compiled in to just save the unknown chunks, so simply skip this 3078 * chunk. If 'keep' is something other than AS_DEFAULT or NEVER then 3079 * the app has erroneously asked for unknown chunk saving when there 3080 * is no support. 3081 */ 3082 if (keep > PNG_HANDLE_CHUNK_NEVER) 3083 png_app_error(png_ptr, "no unknown chunk support available"); 3084 3085 png_crc_finish(png_ptr, length); 3086 } 3087 # endif 3088 3089 # ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED 3090 /* Now store the chunk in the chunk list if appropriate, and if the limits 3091 * permit it. 3092 */ 3093 if (keep == PNG_HANDLE_CHUNK_ALWAYS || 3094 (keep == PNG_HANDLE_CHUNK_IF_SAFE && 3095 PNG_CHUNK_ANCILLARY(png_ptr->chunk_name))) 3096 { 3097 # ifdef PNG_USER_LIMITS_SUPPORTED 3098 switch (png_ptr->user_chunk_cache_max) 3099 { 3100 case 2: 3101 png_ptr->user_chunk_cache_max = 1; 3102 png_chunk_benign_error(png_ptr, "no space in chunk cache"); 3103 /* FALLTHROUGH */ 3104 case 1: 3105 /* NOTE: prior to 1.6.0 this case resulted in an unknown critical 3106 * chunk being skipped, now there will be a hard error below. 3107 */ 3108 break; 3109 3110 default: /* not at limit */ 3111 --(png_ptr->user_chunk_cache_max); 3112 /* FALLTHROUGH */ 3113 case 0: /* no limit */ 3114 # endif /* USER_LIMITS */ 3115 /* Here when the limit isn't reached or when limits are compiled 3116 * out; store the chunk. 3117 */ 3118 png_set_unknown_chunks(png_ptr, info_ptr, 3119 &png_ptr->unknown_chunk, 1); 3120 handled = 1; 3121 # ifdef PNG_USER_LIMITS_SUPPORTED 3122 break; 3123 } 3124 # endif 3125 } 3126 # else /* no store support: the chunk must be handled by the user callback */ 3127 PNG_UNUSED(info_ptr) 3128 # endif 3129 3130 /* Regardless of the error handling below the cached data (if any) can be 3131 * freed now. Notice that the data is not freed if there is a png_error, but 3132 * it will be freed by destroy_read_struct. 3133 */ 3134 if (png_ptr->unknown_chunk.data != NULL) 3135 png_free(png_ptr, png_ptr->unknown_chunk.data); 3136 png_ptr->unknown_chunk.data = NULL; 3137 3138 #else /* !PNG_READ_UNKNOWN_CHUNKS_SUPPORTED */ 3139 /* There is no support to read an unknown chunk, so just skip it. */ 3140 png_crc_finish(png_ptr, length); 3141 PNG_UNUSED(info_ptr) 3142 PNG_UNUSED(keep) 3143 #endif /* !READ_UNKNOWN_CHUNKS */ 3144 3145 /* Check for unhandled critical chunks */ 3146 if (handled == 0 && PNG_CHUNK_CRITICAL(png_ptr->chunk_name)) 3147 png_chunk_error(png_ptr, "unhandled critical chunk"); 3148 } 3149 3150 /* This function is called to verify that a chunk name is valid. 3151 * This function can't have the "critical chunk check" incorporated 3152 * into it, since in the future we will need to be able to call user 3153 * functions to handle unknown critical chunks after we check that 3154 * the chunk name itself is valid. 3155 */ 3156 3157 /* Bit hacking: the test for an invalid byte in the 4 byte chunk name is: 3158 * 3159 * ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97)) 3160 */ 3161 3162 void /* PRIVATE */ 3163 png_check_chunk_name(png_const_structrp png_ptr, const png_uint_32 chunk_name) 3164 { 3165 int i; 3166 png_uint_32 cn=chunk_name; 3167 3168 png_debug(1, "in png_check_chunk_name"); 3169 3170 for (i=1; i<=4; ++i) 3171 { 3172 int c = cn & 0xff; 3173 3174 if (c < 65 || c > 122 || (c > 90 && c < 97)) 3175 png_chunk_error(png_ptr, "invalid chunk type"); 3176 3177 cn >>= 8; 3178 } 3179 } 3180 3181 void /* PRIVATE */ 3182 png_check_chunk_length(png_const_structrp png_ptr, const png_uint_32 length) 3183 { 3184 png_alloc_size_t limit = PNG_UINT_31_MAX; 3185 3186 # ifdef PNG_SET_USER_LIMITS_SUPPORTED 3187 if (png_ptr->user_chunk_malloc_max > 0 && 3188 png_ptr->user_chunk_malloc_max < limit) 3189 limit = png_ptr->user_chunk_malloc_max; 3190 # elif PNG_USER_CHUNK_MALLOC_MAX > 0 3191 if (PNG_USER_CHUNK_MALLOC_MAX < limit) 3192 limit = PNG_USER_CHUNK_MALLOC_MAX; 3193 # endif 3194 if (png_ptr->chunk_name == png_IDAT) 3195 { 3196 png_alloc_size_t idat_limit = PNG_UINT_31_MAX; 3197 size_t row_factor = 3198 (size_t)png_ptr->width 3199 * (size_t)png_ptr->channels 3200 * (png_ptr->bit_depth > 8? 2: 1) 3201 + 1 3202 + (png_ptr->interlaced? 6: 0); 3203 if (png_ptr->height > PNG_UINT_32_MAX/row_factor) 3204 idat_limit = PNG_UINT_31_MAX; 3205 else 3206 idat_limit = png_ptr->height * row_factor; 3207 row_factor = row_factor > 32566? 32566 : row_factor; 3208 idat_limit += 6 + 5*(idat_limit/row_factor+1); /* zlib+deflate overhead */ 3209 idat_limit=idat_limit < PNG_UINT_31_MAX? idat_limit : PNG_UINT_31_MAX; 3210 limit = limit < idat_limit? idat_limit : limit; 3211 } 3212 3213 if (length > limit) 3214 { 3215 png_debug2(0," length = %lu, limit = %lu", 3216 (unsigned long)length,(unsigned long)limit); 3217 png_chunk_error(png_ptr, "chunk data is too large"); 3218 } 3219 } 3220 3221 /* Combines the row recently read in with the existing pixels in the row. This 3222 * routine takes care of alpha and transparency if requested. This routine also 3223 * handles the two methods of progressive display of interlaced images, 3224 * depending on the 'display' value; if 'display' is true then the whole row 3225 * (dp) is filled from the start by replicating the available pixels. If 3226 * 'display' is false only those pixels present in the pass are filled in. 3227 */ 3228 void /* PRIVATE */ 3229 png_combine_row(png_const_structrp png_ptr, png_bytep dp, int display) 3230 { 3231 unsigned int pixel_depth = png_ptr->transformed_pixel_depth; 3232 png_const_bytep sp = png_ptr->row_buf + 1; 3233 png_alloc_size_t row_width = png_ptr->width; 3234 unsigned int pass = png_ptr->pass; 3235 png_bytep end_ptr = 0; 3236 png_byte end_byte = 0; 3237 unsigned int end_mask; 3238 3239 png_debug(1, "in png_combine_row"); 3240 3241 /* Added in 1.5.6: it should not be possible to enter this routine until at 3242 * least one row has been read from the PNG data and transformed. 3243 */ 3244 if (pixel_depth == 0) 3245 png_error(png_ptr, "internal row logic error"); 3246 3247 /* Added in 1.5.4: the pixel depth should match the information returned by 3248 * any call to png_read_update_info at this point. Do not continue if we got 3249 * this wrong. 3250 */ 3251 if (png_ptr->info_rowbytes != 0 && png_ptr->info_rowbytes != 3252 PNG_ROWBYTES(pixel_depth, row_width)) 3253 png_error(png_ptr, "internal row size calculation error"); 3254 3255 /* Don't expect this to ever happen: */ 3256 if (row_width == 0) 3257 png_error(png_ptr, "internal row width error"); 3258 3259 /* Preserve the last byte in cases where only part of it will be overwritten, 3260 * the multiply below may overflow, we don't care because ANSI-C guarantees 3261 * we get the low bits. 3262 */ 3263 end_mask = (pixel_depth * row_width) & 7; 3264 if (end_mask != 0) 3265 { 3266 /* end_ptr == NULL is a flag to say do nothing */ 3267 end_ptr = dp + PNG_ROWBYTES(pixel_depth, row_width) - 1; 3268 end_byte = *end_ptr; 3269 # ifdef PNG_READ_PACKSWAP_SUPPORTED 3270 if ((png_ptr->transformations & PNG_PACKSWAP) != 0) 3271 /* little-endian byte */ 3272 end_mask = (unsigned int)(0xff << end_mask); 3273 3274 else /* big-endian byte */ 3275 # endif 3276 end_mask = 0xff >> end_mask; 3277 /* end_mask is now the bits to *keep* from the destination row */ 3278 } 3279 3280 /* For non-interlaced images this reduces to a memcpy(). A memcpy() 3281 * will also happen if interlacing isn't supported or if the application 3282 * does not call png_set_interlace_handling(). In the latter cases the 3283 * caller just gets a sequence of the unexpanded rows from each interlace 3284 * pass. 3285 */ 3286 #ifdef PNG_READ_INTERLACING_SUPPORTED 3287 if (png_ptr->interlaced != 0 && 3288 (png_ptr->transformations & PNG_INTERLACE) != 0 && 3289 pass < 6 && (display == 0 || 3290 /* The following copies everything for 'display' on passes 0, 2 and 4. */ 3291 (display == 1 && (pass & 1) != 0))) 3292 { 3293 /* Narrow images may have no bits in a pass; the caller should handle 3294 * this, but this test is cheap: 3295 */ 3296 if (row_width <= PNG_PASS_START_COL(pass)) 3297 return; 3298 3299 if (pixel_depth < 8) 3300 { 3301 /* For pixel depths up to 4 bpp the 8-pixel mask can be expanded to fit 3302 * into 32 bits, then a single loop over the bytes using the four byte 3303 * values in the 32-bit mask can be used. For the 'display' option the 3304 * expanded mask may also not require any masking within a byte. To 3305 * make this work the PACKSWAP option must be taken into account - it 3306 * simply requires the pixels to be reversed in each byte. 3307 * 3308 * The 'regular' case requires a mask for each of the first 6 passes, 3309 * the 'display' case does a copy for the even passes in the range 3310 * 0..6. This has already been handled in the test above. 3311 * 3312 * The masks are arranged as four bytes with the first byte to use in 3313 * the lowest bits (little-endian) regardless of the order (PACKSWAP or 3314 * not) of the pixels in each byte. 3315 * 3316 * NOTE: the whole of this logic depends on the caller of this function 3317 * only calling it on rows appropriate to the pass. This function only 3318 * understands the 'x' logic; the 'y' logic is handled by the caller. 3319 * 3320 * The following defines allow generation of compile time constant bit 3321 * masks for each pixel depth and each possibility of swapped or not 3322 * swapped bytes. Pass 'p' is in the range 0..6; 'x', a pixel index, 3323 * is in the range 0..7; and the result is 1 if the pixel is to be 3324 * copied in the pass, 0 if not. 'S' is for the sparkle method, 'B' 3325 * for the block method. 3326 * 3327 * With some compilers a compile time expression of the general form: 3328 * 3329 * (shift >= 32) ? (a >> (shift-32)) : (b >> shift) 3330 * 3331 * Produces warnings with values of 'shift' in the range 33 to 63 3332 * because the right hand side of the ?: expression is evaluated by 3333 * the compiler even though it isn't used. Microsoft Visual C (various 3334 * versions) and the Intel C compiler are known to do this. To avoid 3335 * this the following macros are used in 1.5.6. This is a temporary 3336 * solution to avoid destabilizing the code during the release process. 3337 */ 3338 # if PNG_USE_COMPILE_TIME_MASKS 3339 # define PNG_LSR(x,s) ((x)>>((s) & 0x1f)) 3340 # define PNG_LSL(x,s) ((x)<<((s) & 0x1f)) 3341 # else 3342 # define PNG_LSR(x,s) ((x)>>(s)) 3343 # define PNG_LSL(x,s) ((x)<<(s)) 3344 # endif 3345 # define S_COPY(p,x) (((p)<4 ? PNG_LSR(0x80088822,(3-(p))*8+(7-(x))) :\ 3346 PNG_LSR(0xaa55ff00,(7-(p))*8+(7-(x)))) & 1) 3347 # define B_COPY(p,x) (((p)<4 ? PNG_LSR(0xff0fff33,(3-(p))*8+(7-(x))) :\ 3348 PNG_LSR(0xff55ff00,(7-(p))*8+(7-(x)))) & 1) 3349 3350 /* Return a mask for pass 'p' pixel 'x' at depth 'd'. The mask is 3351 * little endian - the first pixel is at bit 0 - however the extra 3352 * parameter 's' can be set to cause the mask position to be swapped 3353 * within each byte, to match the PNG format. This is done by XOR of 3354 * the shift with 7, 6 or 4 for bit depths 1, 2 and 4. 3355 */ 3356 # define PIXEL_MASK(p,x,d,s) \ 3357 (PNG_LSL(((PNG_LSL(1U,(d)))-1),(((x)*(d))^((s)?8-(d):0)))) 3358 3359 /* Hence generate the appropriate 'block' or 'sparkle' pixel copy mask. 3360 */ 3361 # define S_MASKx(p,x,d,s) (S_COPY(p,x)?PIXEL_MASK(p,x,d,s):0) 3362 # define B_MASKx(p,x,d,s) (B_COPY(p,x)?PIXEL_MASK(p,x,d,s):0) 3363 3364 /* Combine 8 of these to get the full mask. For the 1-bpp and 2-bpp 3365 * cases the result needs replicating, for the 4-bpp case the above 3366 * generates a full 32 bits. 3367 */ 3368 # define MASK_EXPAND(m,d) ((m)*((d)==1?0x01010101:((d)==2?0x00010001:1))) 3369 3370 # define S_MASK(p,d,s) MASK_EXPAND(S_MASKx(p,0,d,s) + S_MASKx(p,1,d,s) +\ 3371 S_MASKx(p,2,d,s) + S_MASKx(p,3,d,s) + S_MASKx(p,4,d,s) +\ 3372 S_MASKx(p,5,d,s) + S_MASKx(p,6,d,s) + S_MASKx(p,7,d,s), d) 3373 3374 # define B_MASK(p,d,s) MASK_EXPAND(B_MASKx(p,0,d,s) + B_MASKx(p,1,d,s) +\ 3375 B_MASKx(p,2,d,s) + B_MASKx(p,3,d,s) + B_MASKx(p,4,d,s) +\ 3376 B_MASKx(p,5,d,s) + B_MASKx(p,6,d,s) + B_MASKx(p,7,d,s), d) 3377 3378 #if PNG_USE_COMPILE_TIME_MASKS 3379 /* Utility macros to construct all the masks for a depth/swap 3380 * combination. The 's' parameter says whether the format is PNG 3381 * (big endian bytes) or not. Only the three odd-numbered passes are 3382 * required for the display/block algorithm. 3383 */ 3384 # define S_MASKS(d,s) { S_MASK(0,d,s), S_MASK(1,d,s), S_MASK(2,d,s),\ 3385 S_MASK(3,d,s), S_MASK(4,d,s), S_MASK(5,d,s) } 3386 3387 # define B_MASKS(d,s) { B_MASK(1,d,s), B_MASK(3,d,s), B_MASK(5,d,s) } 3388 3389 # define DEPTH_INDEX(d) ((d)==1?0:((d)==2?1:2)) 3390 3391 /* Hence the pre-compiled masks indexed by PACKSWAP (or not), depth and 3392 * then pass: 3393 */ 3394 static PNG_CONST png_uint_32 row_mask[2/*PACKSWAP*/][3/*depth*/][6] = 3395 { 3396 /* Little-endian byte masks for PACKSWAP */ 3397 { S_MASKS(1,0), S_MASKS(2,0), S_MASKS(4,0) }, 3398 /* Normal (big-endian byte) masks - PNG format */ 3399 { S_MASKS(1,1), S_MASKS(2,1), S_MASKS(4,1) } 3400 }; 3401 3402 /* display_mask has only three entries for the odd passes, so index by 3403 * pass>>1. 3404 */ 3405 static PNG_CONST png_uint_32 display_mask[2][3][3] = 3406 { 3407 /* Little-endian byte masks for PACKSWAP */ 3408 { B_MASKS(1,0), B_MASKS(2,0), B_MASKS(4,0) }, 3409 /* Normal (big-endian byte) masks - PNG format */ 3410 { B_MASKS(1,1), B_MASKS(2,1), B_MASKS(4,1) } 3411 }; 3412 3413 # define MASK(pass,depth,display,png)\ 3414 ((display)?display_mask[png][DEPTH_INDEX(depth)][pass>>1]:\ 3415 row_mask[png][DEPTH_INDEX(depth)][pass]) 3416 3417 #else /* !PNG_USE_COMPILE_TIME_MASKS */ 3418 /* This is the runtime alternative: it seems unlikely that this will 3419 * ever be either smaller or faster than the compile time approach. 3420 */ 3421 # define MASK(pass,depth,display,png)\ 3422 ((display)?B_MASK(pass,depth,png):S_MASK(pass,depth,png)) 3423 #endif /* !USE_COMPILE_TIME_MASKS */ 3424 3425 /* Use the appropriate mask to copy the required bits. In some cases 3426 * the byte mask will be 0 or 0xff; optimize these cases. row_width is 3427 * the number of pixels, but the code copies bytes, so it is necessary 3428 * to special case the end. 3429 */ 3430 png_uint_32 pixels_per_byte = 8 / pixel_depth; 3431 png_uint_32 mask; 3432 3433 # ifdef PNG_READ_PACKSWAP_SUPPORTED 3434 if ((png_ptr->transformations & PNG_PACKSWAP) != 0) 3435 mask = MASK(pass, pixel_depth, display, 0); 3436 3437 else 3438 # endif 3439 mask = MASK(pass, pixel_depth, display, 1); 3440 3441 for (;;) 3442 { 3443 png_uint_32 m; 3444 3445 /* It doesn't matter in the following if png_uint_32 has more than 3446 * 32 bits because the high bits always match those in m<<24; it is, 3447 * however, essential to use OR here, not +, because of this. 3448 */ 3449 m = mask; 3450 mask = (m >> 8) | (m << 24); /* rotate right to good compilers */ 3451 m &= 0xff; 3452 3453 if (m != 0) /* something to copy */ 3454 { 3455 if (m != 0xff) 3456 *dp = (png_byte)((*dp & ~m) | (*sp & m)); 3457 else 3458 *dp = *sp; 3459 } 3460 3461 /* NOTE: this may overwrite the last byte with garbage if the image 3462 * is not an exact number of bytes wide; libpng has always done 3463 * this. 3464 */ 3465 if (row_width <= pixels_per_byte) 3466 break; /* May need to restore part of the last byte */ 3467 3468 row_width -= pixels_per_byte; 3469 ++dp; 3470 ++sp; 3471 } 3472 } 3473 3474 else /* pixel_depth >= 8 */ 3475 { 3476 unsigned int bytes_to_copy, bytes_to_jump; 3477 3478 /* Validate the depth - it must be a multiple of 8 */ 3479 if (pixel_depth & 7) 3480 png_error(png_ptr, "invalid user transform pixel depth"); 3481 3482 pixel_depth >>= 3; /* now in bytes */ 3483 row_width *= pixel_depth; 3484 3485 /* Regardless of pass number the Adam 7 interlace always results in a 3486 * fixed number of pixels to copy then to skip. There may be a 3487 * different number of pixels to skip at the start though. 3488 */ 3489 { 3490 unsigned int offset = PNG_PASS_START_COL(pass) * pixel_depth; 3491 3492 row_width -= offset; 3493 dp += offset; 3494 sp += offset; 3495 } 3496 3497 /* Work out the bytes to copy. */ 3498 if (display != 0) 3499 { 3500 /* When doing the 'block' algorithm the pixel in the pass gets 3501 * replicated to adjacent pixels. This is why the even (0,2,4,6) 3502 * passes are skipped above - the entire expanded row is copied. 3503 */ 3504 bytes_to_copy = (1<<((6-pass)>>1)) * pixel_depth; 3505 3506 /* But don't allow this number to exceed the actual row width. */ 3507 if (bytes_to_copy > row_width) 3508 bytes_to_copy = (unsigned int)/*SAFE*/row_width; 3509 } 3510 3511 else /* normal row; Adam7 only ever gives us one pixel to copy. */ 3512 bytes_to_copy = pixel_depth; 3513 3514 /* In Adam7 there is a constant offset between where the pixels go. */ 3515 bytes_to_jump = PNG_PASS_COL_OFFSET(pass) * pixel_depth; 3516 3517 /* And simply copy these bytes. Some optimization is possible here, 3518 * depending on the value of 'bytes_to_copy'. Special case the low 3519 * byte counts, which we know to be frequent. 3520 * 3521 * Notice that these cases all 'return' rather than 'break' - this 3522 * avoids an unnecessary test on whether to restore the last byte 3523 * below. 3524 */ 3525 switch (bytes_to_copy) 3526 { 3527 case 1: 3528 for (;;) 3529 { 3530 *dp = *sp; 3531 3532 if (row_width <= bytes_to_jump) 3533 return; 3534 3535 dp += bytes_to_jump; 3536 sp += bytes_to_jump; 3537 row_width -= bytes_to_jump; 3538 } 3539 3540 case 2: 3541 /* There is a possibility of a partial copy at the end here; this 3542 * slows the code down somewhat. 3543 */ 3544 do 3545 { 3546 dp[0] = sp[0]; dp[1] = sp[1]; 3547 3548 if (row_width <= bytes_to_jump) 3549 return; 3550 3551 sp += bytes_to_jump; 3552 dp += bytes_to_jump; 3553 row_width -= bytes_to_jump; 3554 } 3555 while (row_width > 1); 3556 3557 /* And there can only be one byte left at this point: */ 3558 *dp = *sp; 3559 return; 3560 3561 case 3: 3562 /* This can only be the RGB case, so each copy is exactly one 3563 * pixel and it is not necessary to check for a partial copy. 3564 */ 3565 for (;;) 3566 { 3567 dp[0] = sp[0]; dp[1] = sp[1]; dp[2] = sp[2]; 3568 3569 if (row_width <= bytes_to_jump) 3570 return; 3571 3572 sp += bytes_to_jump; 3573 dp += bytes_to_jump; 3574 row_width -= bytes_to_jump; 3575 } 3576 3577 default: 3578 #if PNG_ALIGN_TYPE != PNG_ALIGN_NONE 3579 /* Check for double byte alignment and, if possible, use a 3580 * 16-bit copy. Don't attempt this for narrow images - ones that 3581 * are less than an interlace panel wide. Don't attempt it for 3582 * wide bytes_to_copy either - use the memcpy there. 3583 */ 3584 if (bytes_to_copy < 16 /*else use memcpy*/ && 3585 png_isaligned(dp, png_uint_16) && 3586 png_isaligned(sp, png_uint_16) && 3587 bytes_to_copy % (sizeof (png_uint_16)) == 0 && 3588 bytes_to_jump % (sizeof (png_uint_16)) == 0) 3589 { 3590 /* Everything is aligned for png_uint_16 copies, but try for 3591 * png_uint_32 first. 3592 */ 3593 if (png_isaligned(dp, png_uint_32) && 3594 png_isaligned(sp, png_uint_32) && 3595 bytes_to_copy % (sizeof (png_uint_32)) == 0 && 3596 bytes_to_jump % (sizeof (png_uint_32)) == 0) 3597 { 3598 png_uint_32p dp32 = png_aligncast(png_uint_32p,dp); 3599 png_const_uint_32p sp32 = png_aligncastconst( 3600 png_const_uint_32p, sp); 3601 size_t skip = (bytes_to_jump-bytes_to_copy) / 3602 (sizeof (png_uint_32)); 3603 3604 do 3605 { 3606 size_t c = bytes_to_copy; 3607 do 3608 { 3609 *dp32++ = *sp32++; 3610 c -= (sizeof (png_uint_32)); 3611 } 3612 while (c > 0); 3613 3614 if (row_width <= bytes_to_jump) 3615 return; 3616 3617 dp32 += skip; 3618 sp32 += skip; 3619 row_width -= bytes_to_jump; 3620 } 3621 while (bytes_to_copy <= row_width); 3622 3623 /* Get to here when the row_width truncates the final copy. 3624 * There will be 1-3 bytes left to copy, so don't try the 3625 * 16-bit loop below. 3626 */ 3627 dp = (png_bytep)dp32; 3628 sp = (png_const_bytep)sp32; 3629 do 3630 *dp++ = *sp++; 3631 while (--row_width > 0); 3632 return; 3633 } 3634 3635 /* Else do it in 16-bit quantities, but only if the size is 3636 * not too large. 3637 */ 3638 else 3639 { 3640 png_uint_16p dp16 = png_aligncast(png_uint_16p, dp); 3641 png_const_uint_16p sp16 = png_aligncastconst( 3642 png_const_uint_16p, sp); 3643 size_t skip = (bytes_to_jump-bytes_to_copy) / 3644 (sizeof (png_uint_16)); 3645 3646 do 3647 { 3648 size_t c = bytes_to_copy; 3649 do 3650 { 3651 *dp16++ = *sp16++; 3652 c -= (sizeof (png_uint_16)); 3653 } 3654 while (c > 0); 3655 3656 if (row_width <= bytes_to_jump) 3657 return; 3658 3659 dp16 += skip; 3660 sp16 += skip; 3661 row_width -= bytes_to_jump; 3662 } 3663 while (bytes_to_copy <= row_width); 3664 3665 /* End of row - 1 byte left, bytes_to_copy > row_width: */ 3666 dp = (png_bytep)dp16; 3667 sp = (png_const_bytep)sp16; 3668 do 3669 *dp++ = *sp++; 3670 while (--row_width > 0); 3671 return; 3672 } 3673 } 3674 #endif /* ALIGN_TYPE code */ 3675 3676 /* The true default - use a memcpy: */ 3677 for (;;) 3678 { 3679 memcpy(dp, sp, bytes_to_copy); 3680 3681 if (row_width <= bytes_to_jump) 3682 return; 3683 3684 sp += bytes_to_jump; 3685 dp += bytes_to_jump; 3686 row_width -= bytes_to_jump; 3687 if (bytes_to_copy > row_width) 3688 bytes_to_copy = (unsigned int)/*SAFE*/row_width; 3689 } 3690 } 3691 3692 /* NOT REACHED*/ 3693 } /* pixel_depth >= 8 */ 3694 3695 /* Here if pixel_depth < 8 to check 'end_ptr' below. */ 3696 } 3697 else 3698 #endif /* READ_INTERLACING */ 3699 3700 /* If here then the switch above wasn't used so just memcpy the whole row 3701 * from the temporary row buffer (notice that this overwrites the end of the 3702 * destination row if it is a partial byte.) 3703 */ 3704 memcpy(dp, sp, PNG_ROWBYTES(pixel_depth, row_width)); 3705 3706 /* Restore the overwritten bits from the last byte if necessary. */ 3707 if (end_ptr != NULL) 3708 *end_ptr = (png_byte)((end_byte & end_mask) | (*end_ptr & ~end_mask)); 3709 } 3710 3711 #ifdef PNG_READ_INTERLACING_SUPPORTED 3712 void /* PRIVATE */ 3713 png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass, 3714 png_uint_32 transformations /* Because these may affect the byte layout */) 3715 { 3716 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ 3717 /* Offset to next interlace block */ 3718 static PNG_CONST unsigned int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1}; 3719 3720 png_debug(1, "in png_do_read_interlace"); 3721 if (row != NULL && row_info != NULL) 3722 { 3723 png_uint_32 final_width; 3724 3725 final_width = row_info->width * png_pass_inc[pass]; 3726 3727 switch (row_info->pixel_depth) 3728 { 3729 case 1: 3730 { 3731 png_bytep sp = row + (size_t)((row_info->width - 1) >> 3); 3732 png_bytep dp = row + (size_t)((final_width - 1) >> 3); 3733 unsigned int sshift, dshift; 3734 unsigned int s_start, s_end; 3735 int s_inc; 3736 int jstop = (int)png_pass_inc[pass]; 3737 png_byte v; 3738 png_uint_32 i; 3739 int j; 3740 3741 #ifdef PNG_READ_PACKSWAP_SUPPORTED 3742 if ((transformations & PNG_PACKSWAP) != 0) 3743 { 3744 sshift = ((row_info->width + 7) & 0x07); 3745 dshift = ((final_width + 7) & 0x07); 3746 s_start = 7; 3747 s_end = 0; 3748 s_inc = -1; 3749 } 3750 3751 else 3752 #endif 3753 { 3754 sshift = 7 - ((row_info->width + 7) & 0x07); 3755 dshift = 7 - ((final_width + 7) & 0x07); 3756 s_start = 0; 3757 s_end = 7; 3758 s_inc = 1; 3759 } 3760 3761 for (i = 0; i < row_info->width; i++) 3762 { 3763 v = (png_byte)((*sp >> sshift) & 0x01); 3764 for (j = 0; j < jstop; j++) 3765 { 3766 unsigned int tmp = *dp & (0x7f7f >> (7 - dshift)); 3767 tmp |= (unsigned int)(v << dshift); 3768 *dp = (png_byte)(tmp & 0xff); 3769 3770 if (dshift == s_end) 3771 { 3772 dshift = s_start; 3773 dp--; 3774 } 3775 3776 else 3777 dshift = (unsigned int)((int)dshift + s_inc); 3778 } 3779 3780 if (sshift == s_end) 3781 { 3782 sshift = s_start; 3783 sp--; 3784 } 3785 3786 else 3787 sshift = (unsigned int)((int)sshift + s_inc); 3788 } 3789 break; 3790 } 3791 3792 case 2: 3793 { 3794 png_bytep sp = row + (png_uint_32)((row_info->width - 1) >> 2); 3795 png_bytep dp = row + (png_uint_32)((final_width - 1) >> 2); 3796 unsigned int sshift, dshift; 3797 unsigned int s_start, s_end; 3798 int s_inc; 3799 int jstop = (int)png_pass_inc[pass]; 3800 png_uint_32 i; 3801 3802 #ifdef PNG_READ_PACKSWAP_SUPPORTED 3803 if ((transformations & PNG_PACKSWAP) != 0) 3804 { 3805 sshift = (((row_info->width + 3) & 0x03) << 1); 3806 dshift = (((final_width + 3) & 0x03) << 1); 3807 s_start = 6; 3808 s_end = 0; 3809 s_inc = -2; 3810 } 3811 3812 else 3813 #endif 3814 { 3815 sshift = ((3 - ((row_info->width + 3) & 0x03)) << 1); 3816 dshift = ((3 - ((final_width + 3) & 0x03)) << 1); 3817 s_start = 0; 3818 s_end = 6; 3819 s_inc = 2; 3820 } 3821 3822 for (i = 0; i < row_info->width; i++) 3823 { 3824 png_byte v; 3825 int j; 3826 3827 v = (png_byte)((*sp >> sshift) & 0x03); 3828 for (j = 0; j < jstop; j++) 3829 { 3830 unsigned int tmp = *dp & (0x3f3f >> (6 - dshift)); 3831 tmp |= (unsigned int)(v << dshift); 3832 *dp = (png_byte)(tmp & 0xff); 3833 3834 if (dshift == s_end) 3835 { 3836 dshift = s_start; 3837 dp--; 3838 } 3839 3840 else 3841 dshift = (unsigned int)((int)dshift + s_inc); 3842 } 3843 3844 if (sshift == s_end) 3845 { 3846 sshift = s_start; 3847 sp--; 3848 } 3849 3850 else 3851 sshift = (unsigned int)((int)sshift + s_inc); 3852 } 3853 break; 3854 } 3855 3856 case 4: 3857 { 3858 png_bytep sp = row + (size_t)((row_info->width - 1) >> 1); 3859 png_bytep dp = row + (size_t)((final_width - 1) >> 1); 3860 unsigned int sshift, dshift; 3861 unsigned int s_start, s_end; 3862 int s_inc; 3863 png_uint_32 i; 3864 int jstop = (int)png_pass_inc[pass]; 3865 3866 #ifdef PNG_READ_PACKSWAP_SUPPORTED 3867 if ((transformations & PNG_PACKSWAP) != 0) 3868 { 3869 sshift = (((row_info->width + 1) & 0x01) << 2); 3870 dshift = (((final_width + 1) & 0x01) << 2); 3871 s_start = 4; 3872 s_end = 0; 3873 s_inc = -4; 3874 } 3875 3876 else 3877 #endif 3878 { 3879 sshift = ((1 - ((row_info->width + 1) & 0x01)) << 2); 3880 dshift = ((1 - ((final_width + 1) & 0x01)) << 2); 3881 s_start = 0; 3882 s_end = 4; 3883 s_inc = 4; 3884 } 3885 3886 for (i = 0; i < row_info->width; i++) 3887 { 3888 png_byte v = (png_byte)((*sp >> sshift) & 0x0f); 3889 int j; 3890 3891 for (j = 0; j < jstop; j++) 3892 { 3893 unsigned int tmp = *dp & (0xf0f >> (4 - dshift)); 3894 tmp |= (unsigned int)(v << dshift); 3895 *dp = (png_byte)(tmp & 0xff); 3896 3897 if (dshift == s_end) 3898 { 3899 dshift = s_start; 3900 dp--; 3901 } 3902 3903 else 3904 dshift = (unsigned int)((int)dshift + s_inc); 3905 } 3906 3907 if (sshift == s_end) 3908 { 3909 sshift = s_start; 3910 sp--; 3911 } 3912 3913 else 3914 sshift = (unsigned int)((int)sshift + s_inc); 3915 } 3916 break; 3917 } 3918 3919 default: 3920 { 3921 size_t pixel_bytes = (row_info->pixel_depth >> 3); 3922 3923 png_bytep sp = row + (size_t)(row_info->width - 1) 3924 * pixel_bytes; 3925 3926 png_bytep dp = row + (size_t)(final_width - 1) * pixel_bytes; 3927 3928 int jstop = (int)png_pass_inc[pass]; 3929 png_uint_32 i; 3930 3931 for (i = 0; i < row_info->width; i++) 3932 { 3933 png_byte v[8]; /* SAFE; pixel_depth does not exceed 64 */ 3934 int j; 3935 3936 memcpy(v, sp, pixel_bytes); 3937 3938 for (j = 0; j < jstop; j++) 3939 { 3940 memcpy(dp, v, pixel_bytes); 3941 dp -= pixel_bytes; 3942 } 3943 3944 sp -= pixel_bytes; 3945 } 3946 break; 3947 } 3948 } 3949 3950 row_info->width = final_width; 3951 row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, final_width); 3952 } 3953 #ifndef PNG_READ_PACKSWAP_SUPPORTED 3954 PNG_UNUSED(transformations) /* Silence compiler warning */ 3955 #endif 3956 } 3957 #endif /* READ_INTERLACING */ 3958 3959 static void 3960 png_read_filter_row_sub(png_row_infop row_info, png_bytep row, 3961 png_const_bytep prev_row) 3962 { 3963 size_t i; 3964 size_t istop = row_info->rowbytes; 3965 unsigned int bpp = (row_info->pixel_depth + 7) >> 3; 3966 png_bytep rp = row + bpp; 3967 3968 PNG_UNUSED(prev_row) 3969 3970 for (i = bpp; i < istop; i++) 3971 { 3972 *rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 0xff); 3973 rp++; 3974 } 3975 } 3976 3977 static void 3978 png_read_filter_row_up(png_row_infop row_info, png_bytep row, 3979 png_const_bytep prev_row) 3980 { 3981 size_t i; 3982 size_t istop = row_info->rowbytes; 3983 png_bytep rp = row; 3984 png_const_bytep pp = prev_row; 3985 3986 for (i = 0; i < istop; i++) 3987 { 3988 *rp = (png_byte)(((int)(*rp) + (int)(*pp++)) & 0xff); 3989 rp++; 3990 } 3991 } 3992 3993 static void 3994 png_read_filter_row_avg(png_row_infop row_info, png_bytep row, 3995 png_const_bytep prev_row) 3996 { 3997 size_t i; 3998 png_bytep rp = row; 3999 png_const_bytep pp = prev_row; 4000 unsigned int bpp = (row_info->pixel_depth + 7) >> 3; 4001 size_t istop = row_info->rowbytes - bpp; 4002 4003 for (i = 0; i < bpp; i++) 4004 { 4005 *rp = (png_byte)(((int)(*rp) + 4006 ((int)(*pp++) / 2 )) & 0xff); 4007 4008 rp++; 4009 } 4010 4011 for (i = 0; i < istop; i++) 4012 { 4013 *rp = (png_byte)(((int)(*rp) + 4014 (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff); 4015 4016 rp++; 4017 } 4018 } 4019 4020 static void 4021 png_read_filter_row_paeth_1byte_pixel(png_row_infop row_info, png_bytep row, 4022 png_const_bytep prev_row) 4023 { 4024 png_bytep rp_end = row + row_info->rowbytes; 4025 int a, c; 4026 4027 /* First pixel/byte */ 4028 c = *prev_row++; 4029 a = *row + c; 4030 *row++ = (png_byte)a; 4031 4032 /* Remainder */ 4033 while (row < rp_end) 4034 { 4035 int b, pa, pb, pc, p; 4036 4037 a &= 0xff; /* From previous iteration or start */ 4038 b = *prev_row++; 4039 4040 p = b - c; 4041 pc = a - c; 4042 4043 #ifdef PNG_USE_ABS 4044 pa = abs(p); 4045 pb = abs(pc); 4046 pc = abs(p + pc); 4047 #else 4048 pa = p < 0 ? -p : p; 4049 pb = pc < 0 ? -pc : pc; 4050 pc = (p + pc) < 0 ? -(p + pc) : p + pc; 4051 #endif 4052 4053 /* Find the best predictor, the least of pa, pb, pc favoring the earlier 4054 * ones in the case of a tie. 4055 */ 4056 if (pb < pa) 4057 { 4058 pa = pb; a = b; 4059 } 4060 if (pc < pa) a = c; 4061 4062 /* Calculate the current pixel in a, and move the previous row pixel to c 4063 * for the next time round the loop 4064 */ 4065 c = b; 4066 a += *row; 4067 *row++ = (png_byte)a; 4068 } 4069 } 4070 4071 static void 4072 png_read_filter_row_paeth_multibyte_pixel(png_row_infop row_info, png_bytep row, 4073 png_const_bytep prev_row) 4074 { 4075 unsigned int bpp = (row_info->pixel_depth + 7) >> 3; 4076 png_bytep rp_end = row + bpp; 4077 4078 /* Process the first pixel in the row completely (this is the same as 'up' 4079 * because there is only one candidate predictor for the first row). 4080 */ 4081 while (row < rp_end) 4082 { 4083 int a = *row + *prev_row++; 4084 *row++ = (png_byte)a; 4085 } 4086 4087 /* Remainder */ 4088 rp_end = rp_end + (row_info->rowbytes - bpp); 4089 4090 while (row < rp_end) 4091 { 4092 int a, b, c, pa, pb, pc, p; 4093 4094 c = *(prev_row - bpp); 4095 a = *(row - bpp); 4096 b = *prev_row++; 4097 4098 p = b - c; 4099 pc = a - c; 4100 4101 #ifdef PNG_USE_ABS 4102 pa = abs(p); 4103 pb = abs(pc); 4104 pc = abs(p + pc); 4105 #else 4106 pa = p < 0 ? -p : p; 4107 pb = pc < 0 ? -pc : pc; 4108 pc = (p + pc) < 0 ? -(p + pc) : p + pc; 4109 #endif 4110 4111 if (pb < pa) 4112 { 4113 pa = pb; a = b; 4114 } 4115 if (pc < pa) a = c; 4116 4117 a += *row; 4118 *row++ = (png_byte)a; 4119 } 4120 } 4121 4122 static void 4123 png_init_filter_functions(png_structrp pp) 4124 /* This function is called once for every PNG image (except for PNG images 4125 * that only use PNG_FILTER_VALUE_NONE for all rows) to set the 4126 * implementations required to reverse the filtering of PNG rows. Reversing 4127 * the filter is the first transformation performed on the row data. It is 4128 * performed in place, therefore an implementation can be selected based on 4129 * the image pixel format. If the implementation depends on image width then 4130 * take care to ensure that it works correctly if the image is interlaced - 4131 * interlacing causes the actual row width to vary. 4132 */ 4133 { 4134 unsigned int bpp = (pp->pixel_depth + 7) >> 3; 4135 4136 pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub; 4137 pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up; 4138 pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg; 4139 if (bpp == 1) 4140 pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = 4141 png_read_filter_row_paeth_1byte_pixel; 4142 else 4143 pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = 4144 png_read_filter_row_paeth_multibyte_pixel; 4145 4146 #ifdef PNG_FILTER_OPTIMIZATIONS 4147 /* To use this define PNG_FILTER_OPTIMIZATIONS as the name of a function to 4148 * call to install hardware optimizations for the above functions; simply 4149 * replace whatever elements of the pp->read_filter[] array with a hardware 4150 * specific (or, for that matter, generic) optimization. 4151 * 4152 * To see an example of this examine what configure.ac does when 4153 * --enable-arm-neon is specified on the command line. 4154 */ 4155 PNG_FILTER_OPTIMIZATIONS(pp, bpp); 4156 #endif 4157 } 4158 4159 void /* PRIVATE */ 4160 png_read_filter_row(png_structrp pp, png_row_infop row_info, png_bytep row, 4161 png_const_bytep prev_row, int filter) 4162 { 4163 /* OPTIMIZATION: DO NOT MODIFY THIS FUNCTION, instead #define 4164 * PNG_FILTER_OPTIMIZATIONS to a function that overrides the generic 4165 * implementations. See png_init_filter_functions above. 4166 */ 4167 if (filter > PNG_FILTER_VALUE_NONE && filter < PNG_FILTER_VALUE_LAST) 4168 { 4169 if (pp->read_filter[0] == NULL) 4170 png_init_filter_functions(pp); 4171 4172 pp->read_filter[filter-1](row_info, row, prev_row); 4173 } 4174 } 4175 4176 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED 4177 void /* PRIVATE */ 4178 png_read_IDAT_data(png_structrp png_ptr, png_bytep output, 4179 png_alloc_size_t avail_out) 4180 { 4181 /* Loop reading IDATs and decompressing the result into output[avail_out] */ 4182 png_ptr->zstream.next_out = output; 4183 png_ptr->zstream.avail_out = 0; /* safety: set below */ 4184 4185 if (output == NULL) 4186 avail_out = 0; 4187 4188 do 4189 { 4190 int ret; 4191 png_byte tmpbuf[PNG_INFLATE_BUF_SIZE]; 4192 4193 if (png_ptr->zstream.avail_in == 0) 4194 { 4195 uInt avail_in; 4196 png_bytep buffer; 4197 4198 while (png_ptr->idat_size == 0) 4199 { 4200 png_crc_finish(png_ptr, 0); 4201 4202 png_ptr->idat_size = png_read_chunk_header(png_ptr); 4203 /* This is an error even in the 'check' case because the code just 4204 * consumed a non-IDAT header. 4205 */ 4206 if (png_ptr->chunk_name != png_IDAT) 4207 png_error(png_ptr, "Not enough image data"); 4208 } 4209 4210 avail_in = png_ptr->IDAT_read_size; 4211 4212 if (avail_in > png_ptr->idat_size) 4213 avail_in = (uInt)png_ptr->idat_size; 4214 4215 /* A PNG with a gradually increasing IDAT size will defeat this attempt 4216 * to minimize memory usage by causing lots of re-allocs, but 4217 * realistically doing IDAT_read_size re-allocs is not likely to be a 4218 * big problem. 4219 */ 4220 buffer = png_read_buffer(png_ptr, avail_in, 0/*error*/); 4221 4222 png_crc_read(png_ptr, buffer, avail_in); 4223 png_ptr->idat_size -= avail_in; 4224 4225 png_ptr->zstream.next_in = buffer; 4226 png_ptr->zstream.avail_in = avail_in; 4227 } 4228 4229 /* And set up the output side. */ 4230 if (output != NULL) /* standard read */ 4231 { 4232 uInt out = ZLIB_IO_MAX; 4233 4234 if (out > avail_out) 4235 out = (uInt)avail_out; 4236 4237 avail_out -= out; 4238 png_ptr->zstream.avail_out = out; 4239 } 4240 4241 else /* after last row, checking for end */ 4242 { 4243 png_ptr->zstream.next_out = tmpbuf; 4244 png_ptr->zstream.avail_out = (sizeof tmpbuf); 4245 } 4246 4247 /* Use NO_FLUSH; this gives zlib the maximum opportunity to optimize the 4248 * process. If the LZ stream is truncated the sequential reader will 4249 * terminally damage the stream, above, by reading the chunk header of the 4250 * following chunk (it then exits with png_error). 4251 * 4252 * TODO: deal more elegantly with truncated IDAT lists. 4253 */ 4254 ret = PNG_INFLATE(png_ptr, Z_NO_FLUSH); 4255 4256 /* Take the unconsumed output back. */ 4257 if (output != NULL) 4258 avail_out += png_ptr->zstream.avail_out; 4259 4260 else /* avail_out counts the extra bytes */ 4261 avail_out += (sizeof tmpbuf) - png_ptr->zstream.avail_out; 4262 4263 png_ptr->zstream.avail_out = 0; 4264 4265 if (ret == Z_STREAM_END) 4266 { 4267 /* Do this for safety; we won't read any more into this row. */ 4268 png_ptr->zstream.next_out = NULL; 4269 4270 png_ptr->mode |= PNG_AFTER_IDAT; 4271 png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED; 4272 4273 if (png_ptr->zstream.avail_in > 0 || png_ptr->idat_size > 0) 4274 png_chunk_benign_error(png_ptr, "Extra compressed data"); 4275 break; 4276 } 4277 4278 if (ret != Z_OK) 4279 { 4280 png_zstream_error(png_ptr, ret); 4281 4282 if (output != NULL) 4283 png_chunk_error(png_ptr, png_ptr->zstream.msg); 4284 4285 else /* checking */ 4286 { 4287 png_chunk_benign_error(png_ptr, png_ptr->zstream.msg); 4288 return; 4289 } 4290 } 4291 } while (avail_out > 0); 4292 4293 if (avail_out > 0) 4294 { 4295 /* The stream ended before the image; this is the same as too few IDATs so 4296 * should be handled the same way. 4297 */ 4298 if (output != NULL) 4299 png_error(png_ptr, "Not enough image data"); 4300 4301 else /* the deflate stream contained extra data */ 4302 png_chunk_benign_error(png_ptr, "Too much image data"); 4303 } 4304 } 4305 4306 void /* PRIVATE */ 4307 png_read_finish_IDAT(png_structrp png_ptr) 4308 { 4309 /* We don't need any more data and the stream should have ended, however the 4310 * LZ end code may actually not have been processed. In this case we must 4311 * read it otherwise stray unread IDAT data or, more likely, an IDAT chunk 4312 * may still remain to be consumed. 4313 */ 4314 if ((png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0) 4315 { 4316 /* The NULL causes png_read_IDAT_data to swallow any remaining bytes in 4317 * the compressed stream, but the stream may be damaged too, so even after 4318 * this call we may need to terminate the zstream ownership. 4319 */ 4320 png_read_IDAT_data(png_ptr, NULL, 0); 4321 png_ptr->zstream.next_out = NULL; /* safety */ 4322 4323 /* Now clear everything out for safety; the following may not have been 4324 * done. 4325 */ 4326 if ((png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0) 4327 { 4328 png_ptr->mode |= PNG_AFTER_IDAT; 4329 png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED; 4330 } 4331 } 4332 4333 /* If the zstream has not been released do it now *and* terminate the reading 4334 * of the final IDAT chunk. 4335 */ 4336 if (png_ptr->zowner == png_IDAT) 4337 { 4338 /* Always do this; the pointers otherwise point into the read buffer. */ 4339 png_ptr->zstream.next_in = NULL; 4340 png_ptr->zstream.avail_in = 0; 4341 4342 /* Now we no longer own the zstream. */ 4343 png_ptr->zowner = 0; 4344 4345 /* The slightly weird semantics of the sequential IDAT reading is that we 4346 * are always in or at the end of an IDAT chunk, so we always need to do a 4347 * crc_finish here. If idat_size is non-zero we also need to read the 4348 * spurious bytes at the end of the chunk now. 4349 */ 4350 (void)png_crc_finish(png_ptr, png_ptr->idat_size); 4351 } 4352 } 4353 4354 void /* PRIVATE */ 4355 png_read_finish_row(png_structrp png_ptr) 4356 { 4357 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ 4358 4359 /* Start of interlace block */ 4360 static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0}; 4361 4362 /* Offset to next interlace block */ 4363 static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1}; 4364 4365 /* Start of interlace block in the y direction */ 4366 static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1}; 4367 4368 /* Offset to next interlace block in the y direction */ 4369 static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2}; 4370 4371 png_debug(1, "in png_read_finish_row"); 4372 png_ptr->row_number++; 4373 if (png_ptr->row_number < png_ptr->num_rows) 4374 return; 4375 4376 if (png_ptr->interlaced != 0) 4377 { 4378 png_ptr->row_number = 0; 4379 4380 /* TO DO: don't do this if prev_row isn't needed (requires 4381 * read-ahead of the next row's filter byte. 4382 */ 4383 memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1); 4384 4385 do 4386 { 4387 png_ptr->pass++; 4388 4389 if (png_ptr->pass >= 7) 4390 break; 4391 4392 png_ptr->iwidth = (png_ptr->width + 4393 png_pass_inc[png_ptr->pass] - 1 - 4394 png_pass_start[png_ptr->pass]) / 4395 png_pass_inc[png_ptr->pass]; 4396 4397 if ((png_ptr->transformations & PNG_INTERLACE) == 0) 4398 { 4399 png_ptr->num_rows = (png_ptr->height + 4400 png_pass_yinc[png_ptr->pass] - 1 - 4401 png_pass_ystart[png_ptr->pass]) / 4402 png_pass_yinc[png_ptr->pass]; 4403 } 4404 4405 else /* if (png_ptr->transformations & PNG_INTERLACE) */ 4406 break; /* libpng deinterlacing sees every row */ 4407 4408 } while (png_ptr->num_rows == 0 || png_ptr->iwidth == 0); 4409 4410 if (png_ptr->pass < 7) 4411 return; 4412 } 4413 4414 /* Here after at the end of the last row of the last pass. */ 4415 png_read_finish_IDAT(png_ptr); 4416 } 4417 #endif /* SEQUENTIAL_READ */ 4418 4419 void /* PRIVATE */ 4420 png_read_start_row(png_structrp png_ptr) 4421 { 4422 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ 4423 4424 /* Start of interlace block */ 4425 static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0}; 4426 4427 /* Offset to next interlace block */ 4428 static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1}; 4429 4430 /* Start of interlace block in the y direction */ 4431 static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1}; 4432 4433 /* Offset to next interlace block in the y direction */ 4434 static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2}; 4435 4436 unsigned int max_pixel_depth; 4437 size_t row_bytes; 4438 4439 png_debug(1, "in png_read_start_row"); 4440 4441 #ifdef PNG_READ_TRANSFORMS_SUPPORTED 4442 png_init_read_transformations(png_ptr); 4443 #endif 4444 if (png_ptr->interlaced != 0) 4445 { 4446 if ((png_ptr->transformations & PNG_INTERLACE) == 0) 4447 png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 - 4448 png_pass_ystart[0]) / png_pass_yinc[0]; 4449 4450 else 4451 png_ptr->num_rows = png_ptr->height; 4452 4453 png_ptr->iwidth = (png_ptr->width + 4454 png_pass_inc[png_ptr->pass] - 1 - 4455 png_pass_start[png_ptr->pass]) / 4456 png_pass_inc[png_ptr->pass]; 4457 } 4458 4459 else 4460 { 4461 png_ptr->num_rows = png_ptr->height; 4462 png_ptr->iwidth = png_ptr->width; 4463 } 4464 4465 max_pixel_depth = (unsigned int)png_ptr->pixel_depth; 4466 4467 /* WARNING: * png_read_transform_info (pngrtran.c) performs a simpler set of 4468 * calculations to calculate the final pixel depth, then 4469 * png_do_read_transforms actually does the transforms. This means that the 4470 * code which effectively calculates this value is actually repeated in three 4471 * separate places. They must all match. Innocent changes to the order of 4472 * transformations can and will break libpng in a way that causes memory 4473 * overwrites. 4474 * 4475 * TODO: fix this. 4476 */ 4477 #ifdef PNG_READ_PACK_SUPPORTED 4478 if ((png_ptr->transformations & PNG_PACK) != 0 && png_ptr->bit_depth < 8) 4479 max_pixel_depth = 8; 4480 #endif 4481 4482 #ifdef PNG_READ_EXPAND_SUPPORTED 4483 if ((png_ptr->transformations & PNG_EXPAND) != 0) 4484 { 4485 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) 4486 { 4487 if (png_ptr->num_trans != 0) 4488 max_pixel_depth = 32; 4489 4490 else 4491 max_pixel_depth = 24; 4492 } 4493 4494 else if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY) 4495 { 4496 if (max_pixel_depth < 8) 4497 max_pixel_depth = 8; 4498 4499 if (png_ptr->num_trans != 0) 4500 max_pixel_depth *= 2; 4501 } 4502 4503 else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB) 4504 { 4505 if (png_ptr->num_trans != 0) 4506 { 4507 max_pixel_depth *= 4; 4508 max_pixel_depth /= 3; 4509 } 4510 } 4511 } 4512 #endif 4513 4514 #ifdef PNG_READ_EXPAND_16_SUPPORTED 4515 if ((png_ptr->transformations & PNG_EXPAND_16) != 0) 4516 { 4517 # ifdef PNG_READ_EXPAND_SUPPORTED 4518 /* In fact it is an error if it isn't supported, but checking is 4519 * the safe way. 4520 */ 4521 if ((png_ptr->transformations & PNG_EXPAND) != 0) 4522 { 4523 if (png_ptr->bit_depth < 16) 4524 max_pixel_depth *= 2; 4525 } 4526 else 4527 # endif 4528 png_ptr->transformations &= ~PNG_EXPAND_16; 4529 } 4530 #endif 4531 4532 #ifdef PNG_READ_FILLER_SUPPORTED 4533 if ((png_ptr->transformations & (PNG_FILLER)) != 0) 4534 { 4535 if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY) 4536 { 4537 if (max_pixel_depth <= 8) 4538 max_pixel_depth = 16; 4539 4540 else 4541 max_pixel_depth = 32; 4542 } 4543 4544 else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB || 4545 png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) 4546 { 4547 if (max_pixel_depth <= 32) 4548 max_pixel_depth = 32; 4549 4550 else 4551 max_pixel_depth = 64; 4552 } 4553 } 4554 #endif 4555 4556 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED 4557 if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0) 4558 { 4559 if ( 4560 #ifdef PNG_READ_EXPAND_SUPPORTED 4561 (png_ptr->num_trans != 0 && 4562 (png_ptr->transformations & PNG_EXPAND) != 0) || 4563 #endif 4564 #ifdef PNG_READ_FILLER_SUPPORTED 4565 (png_ptr->transformations & (PNG_FILLER)) != 0 || 4566 #endif 4567 png_ptr->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) 4568 { 4569 if (max_pixel_depth <= 16) 4570 max_pixel_depth = 32; 4571 4572 else 4573 max_pixel_depth = 64; 4574 } 4575 4576 else 4577 { 4578 if (max_pixel_depth <= 8) 4579 { 4580 if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA) 4581 max_pixel_depth = 32; 4582 4583 else 4584 max_pixel_depth = 24; 4585 } 4586 4587 else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA) 4588 max_pixel_depth = 64; 4589 4590 else 4591 max_pixel_depth = 48; 4592 } 4593 } 4594 #endif 4595 4596 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) && \ 4597 defined(PNG_USER_TRANSFORM_PTR_SUPPORTED) 4598 if ((png_ptr->transformations & PNG_USER_TRANSFORM) != 0) 4599 { 4600 unsigned int user_pixel_depth = png_ptr->user_transform_depth * 4601 png_ptr->user_transform_channels; 4602 4603 if (user_pixel_depth > max_pixel_depth) 4604 max_pixel_depth = user_pixel_depth; 4605 } 4606 #endif 4607 4608 /* This value is stored in png_struct and double checked in the row read 4609 * code. 4610 */ 4611 png_ptr->maximum_pixel_depth = (png_byte)max_pixel_depth; 4612 png_ptr->transformed_pixel_depth = 0; /* calculated on demand */ 4613 4614 /* Align the width on the next larger 8 pixels. Mainly used 4615 * for interlacing 4616 */ 4617 row_bytes = ((png_ptr->width + 7) & ~((png_uint_32)7)); 4618 /* Calculate the maximum bytes needed, adding a byte and a pixel 4619 * for safety's sake 4620 */ 4621 row_bytes = PNG_ROWBYTES(max_pixel_depth, row_bytes) + 4622 1 + ((max_pixel_depth + 7) >> 3U); 4623 4624 #ifdef PNG_MAX_MALLOC_64K 4625 if (row_bytes > (png_uint_32)65536L) 4626 png_error(png_ptr, "This image requires a row greater than 64KB"); 4627 #endif 4628 4629 if (row_bytes + 48 > png_ptr->old_big_row_buf_size) 4630 { 4631 png_free(png_ptr, png_ptr->big_row_buf); 4632 png_free(png_ptr, png_ptr->big_prev_row); 4633 4634 if (png_ptr->interlaced != 0) 4635 png_ptr->big_row_buf = (png_bytep)png_calloc(png_ptr, 4636 row_bytes + 48); 4637 4638 else 4639 png_ptr->big_row_buf = (png_bytep)png_malloc(png_ptr, row_bytes + 48); 4640 4641 png_ptr->big_prev_row = (png_bytep)png_malloc(png_ptr, row_bytes + 48); 4642 4643 #ifdef PNG_ALIGNED_MEMORY_SUPPORTED 4644 /* Use 16-byte aligned memory for row_buf with at least 16 bytes 4645 * of padding before and after row_buf; treat prev_row similarly. 4646 * NOTE: the alignment is to the start of the pixels, one beyond the start 4647 * of the buffer, because of the filter byte. Prior to libpng 1.5.6 this 4648 * was incorrect; the filter byte was aligned, which had the exact 4649 * opposite effect of that intended. 4650 */ 4651 { 4652 png_bytep temp = png_ptr->big_row_buf + 32; 4653 int extra = (int)((temp - (png_bytep)0) & 0x0f); 4654 png_ptr->row_buf = temp - extra - 1/*filter byte*/; 4655 4656 temp = png_ptr->big_prev_row + 32; 4657 extra = (int)((temp - (png_bytep)0) & 0x0f); 4658 png_ptr->prev_row = temp - extra - 1/*filter byte*/; 4659 } 4660 4661 #else 4662 /* Use 31 bytes of padding before and 17 bytes after row_buf. */ 4663 png_ptr->row_buf = png_ptr->big_row_buf + 31; 4664 png_ptr->prev_row = png_ptr->big_prev_row + 31; 4665 #endif 4666 png_ptr->old_big_row_buf_size = row_bytes + 48; 4667 } 4668 4669 #ifdef PNG_MAX_MALLOC_64K 4670 if (png_ptr->rowbytes > 65535) 4671 png_error(png_ptr, "This image requires a row greater than 64KB"); 4672 4673 #endif 4674 if (png_ptr->rowbytes > (PNG_SIZE_MAX - 1)) 4675 png_error(png_ptr, "Row has too many bytes to allocate in memory"); 4676 4677 memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1); 4678 4679 png_debug1(3, "width = %u,", png_ptr->width); 4680 png_debug1(3, "height = %u,", png_ptr->height); 4681 png_debug1(3, "iwidth = %u,", png_ptr->iwidth); 4682 png_debug1(3, "num_rows = %u,", png_ptr->num_rows); 4683 png_debug1(3, "rowbytes = %lu,", (unsigned long)png_ptr->rowbytes); 4684 png_debug1(3, "irowbytes = %lu", 4685 (unsigned long)PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->iwidth) + 1); 4686 4687 /* The sequential reader needs a buffer for IDAT, but the progressive reader 4688 * does not, so free the read buffer now regardless; the sequential reader 4689 * reallocates it on demand. 4690 */ 4691 if (png_ptr->read_buffer != NULL) 4692 { 4693 png_bytep buffer = png_ptr->read_buffer; 4694 4695 png_ptr->read_buffer_size = 0; 4696 png_ptr->read_buffer = NULL; 4697 png_free(png_ptr, buffer); 4698 } 4699 4700 /* Finally claim the zstream for the inflate of the IDAT data, use the bits 4701 * value from the stream (note that this will result in a fatal error if the 4702 * IDAT stream has a bogus deflate header window_bits value, but this should 4703 * not be happening any longer!) 4704 */ 4705 if (png_inflate_claim(png_ptr, png_IDAT) != Z_OK) 4706 png_error(png_ptr, png_ptr->zstream.msg); 4707 4708 png_ptr->flags |= PNG_FLAG_ROW_INIT; 4709 } 4710 #endif /* READ */