| |
| /* pngrutil.c - utilities to read a PNG file |
| * |
| * Copyright (c) 2018 Cosmin Truta |
| * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson |
| * Copyright (c) 1996-1997 Andreas Dilger |
| * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc. |
| * |
| * This code is released under the libpng license. |
| * For conditions of distribution and use, see the disclaimer |
| * and license in png.h |
| * |
| * This file contains routines that are only called from within |
| * libpng itself during the course of reading an image. |
| */ |
| |
| #include "pngpriv.h" |
| |
| #ifdef PNG_READ_SUPPORTED |
| |
| png_uint_32 PNGAPI |
| png_get_uint_31(png_const_structrp png_ptr, png_const_bytep buf) |
| { |
| png_uint_32 uval = png_get_uint_32(buf); |
| |
| if (uval > PNG_UINT_31_MAX) |
| png_error(png_ptr, "PNG unsigned integer out of range"); |
| |
| return (uval); |
| } |
| |
| #if defined(PNG_READ_gAMA_SUPPORTED) || defined(PNG_READ_cHRM_SUPPORTED) |
| /* The following is a variation on the above for use with the fixed |
| * point values used for gAMA and cHRM. Instead of png_error it |
| * issues a warning and returns (-1) - an invalid value because both |
| * gAMA and cHRM use *unsigned* integers for fixed point values. |
| */ |
| #define PNG_FIXED_ERROR (-1) |
| |
| static png_fixed_point /* PRIVATE */ |
| png_get_fixed_point(png_structrp png_ptr, png_const_bytep buf) |
| { |
| png_uint_32 uval = png_get_uint_32(buf); |
| |
| if (uval <= PNG_UINT_31_MAX) |
| return (png_fixed_point)uval; /* known to be in range */ |
| |
| /* The caller can turn off the warning by passing NULL. */ |
| if (png_ptr != NULL) |
| png_warning(png_ptr, "PNG fixed point integer out of range"); |
| |
| return PNG_FIXED_ERROR; |
| } |
| #endif |
| |
| #ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED |
| /* NOTE: the read macros will obscure these definitions, so that if |
| * PNG_USE_READ_MACROS is set the library will not use them internally, |
| * but the APIs will still be available externally. |
| * |
| * The parentheses around "PNGAPI function_name" in the following three |
| * functions are necessary because they allow the macros to co-exist with |
| * these (unused but exported) functions. |
| */ |
| |
| /* Grab an unsigned 32-bit integer from a buffer in big-endian format. */ |
| png_uint_32 (PNGAPI |
| png_get_uint_32)(png_const_bytep buf) |
| { |
| png_uint_32 uval = |
| ((png_uint_32)(*(buf )) << 24) + |
| ((png_uint_32)(*(buf + 1)) << 16) + |
| ((png_uint_32)(*(buf + 2)) << 8) + |
| ((png_uint_32)(*(buf + 3)) ) ; |
| |
| return uval; |
| } |
| |
| /* Grab a signed 32-bit integer from a buffer in big-endian format. The |
| * data is stored in the PNG file in two's complement format and there |
| * is no guarantee that a 'png_int_32' is exactly 32 bits, therefore |
| * the following code does a two's complement to native conversion. |
| */ |
| png_int_32 (PNGAPI |
| png_get_int_32)(png_const_bytep buf) |
| { |
| png_uint_32 uval = png_get_uint_32(buf); |
| if ((uval & 0x80000000) == 0) /* non-negative */ |
| return (png_int_32)uval; |
| |
| uval = (uval ^ 0xffffffff) + 1; /* 2's complement: -x = ~x+1 */ |
| if ((uval & 0x80000000) == 0) /* no overflow */ |
| return -(png_int_32)uval; |
| /* The following has to be safe; this function only gets called on PNG data |
| * and if we get here that data is invalid. 0 is the most safe value and |
| * if not then an attacker would surely just generate a PNG with 0 instead. |
| */ |
| return 0; |
| } |
| |
| /* Grab an unsigned 16-bit integer from a buffer in big-endian format. */ |
| png_uint_16 (PNGAPI |
| png_get_uint_16)(png_const_bytep buf) |
| { |
| /* ANSI-C requires an int value to accommodate at least 16 bits so this |
| * works and allows the compiler not to worry about possible narrowing |
| * on 32-bit systems. (Pre-ANSI systems did not make integers smaller |
| * than 16 bits either.) |
| */ |
| unsigned int val = |
| ((unsigned int)(*buf) << 8) + |
| ((unsigned int)(*(buf + 1))); |
| |
| return (png_uint_16)val; |
| } |
| |
| #endif /* READ_INT_FUNCTIONS */ |
| |
| /* Read and check the PNG file signature */ |
| void /* PRIVATE */ |
| png_read_sig(png_structrp png_ptr, png_inforp info_ptr) |
| { |
| size_t num_checked, num_to_check; |
| |
| /* Exit if the user application does not expect a signature. */ |
| if (png_ptr->sig_bytes >= 8) |
| return; |
| |
| num_checked = png_ptr->sig_bytes; |
| num_to_check = 8 - num_checked; |
| |
| #ifdef PNG_IO_STATE_SUPPORTED |
| png_ptr->io_state = PNG_IO_READING | PNG_IO_SIGNATURE; |
| #endif |
| |
| /* The signature must be serialized in a single I/O call. */ |
| png_read_data(png_ptr, &(info_ptr->signature[num_checked]), num_to_check); |
| png_ptr->sig_bytes = 8; |
| |
| if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check) != 0) |
| { |
| if (num_checked < 4 && |
| png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4)) |
| png_error(png_ptr, "Not a PNG file"); |
| else |
| png_error(png_ptr, "PNG file corrupted by ASCII conversion"); |
| } |
| if (num_checked < 3) |
| png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE; |
| } |
| |
| /* Read the chunk header (length + type name). |
| * Put the type name into png_ptr->chunk_name, and return the length. |
| */ |
| png_uint_32 /* PRIVATE */ |
| png_read_chunk_header(png_structrp png_ptr) |
| { |
| png_byte buf[8]; |
| png_uint_32 length; |
| |
| #ifdef PNG_IO_STATE_SUPPORTED |
| png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_HDR; |
| #endif |
| |
| /* Read the length and the chunk name. |
| * This must be performed in a single I/O call. |
| */ |
| png_read_data(png_ptr, buf, 8); |
| length = png_get_uint_31(png_ptr, buf); |
| |
| /* Put the chunk name into png_ptr->chunk_name. */ |
| png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(buf+4); |
| |
| png_debug2(0, "Reading %lx chunk, length = %lu", |
| (unsigned long)png_ptr->chunk_name, (unsigned long)length); |
| |
| /* Reset the crc and run it over the chunk name. */ |
| png_reset_crc(png_ptr); |
| png_calculate_crc(png_ptr, buf + 4, 4); |
| |
| /* Check to see if chunk name is valid. */ |
| png_check_chunk_name(png_ptr, png_ptr->chunk_name); |
| |
| /* Check for too-large chunk length */ |
| png_check_chunk_length(png_ptr, length); |
| |
| #ifdef PNG_IO_STATE_SUPPORTED |
| png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_DATA; |
| #endif |
| |
| return length; |
| } |
| |
| /* Read data, and (optionally) run it through the CRC. */ |
| void /* PRIVATE */ |
| png_crc_read(png_structrp png_ptr, png_bytep buf, png_uint_32 length) |
| { |
| if (png_ptr == NULL) |
| return; |
| |
| png_read_data(png_ptr, buf, length); |
| png_calculate_crc(png_ptr, buf, length); |
| } |
| |
| /* Optionally skip data and then check the CRC. Depending on whether we |
| * are reading an ancillary or critical chunk, and how the program has set |
| * things up, we may calculate the CRC on the data and print a message. |
| * Returns '1' if there was a CRC error, '0' otherwise. |
| */ |
| int /* PRIVATE */ |
| png_crc_finish(png_structrp png_ptr, png_uint_32 skip) |
| { |
| /* The size of the local buffer for inflate is a good guess as to a |
| * reasonable size to use for buffering reads from the application. |
| */ |
| while (skip > 0) |
| { |
| png_uint_32 len; |
| png_byte tmpbuf[PNG_INFLATE_BUF_SIZE]; |
| |
| len = (sizeof tmpbuf); |
| if (len > skip) |
| len = skip; |
| skip -= len; |
| |
| png_crc_read(png_ptr, tmpbuf, len); |
| } |
| |
| if (png_crc_error(png_ptr) != 0) |
| { |
| if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name) != 0 ? |
| (png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) == 0 : |
| (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_USE) != 0) |
| { |
| png_chunk_warning(png_ptr, "CRC error"); |
| } |
| |
| else |
| png_chunk_error(png_ptr, "CRC error"); |
| |
| return (1); |
| } |
| |
| return (0); |
| } |
| |
| /* Compare the CRC stored in the PNG file with that calculated by libpng from |
| * the data it has read thus far. |
| */ |
| int /* PRIVATE */ |
| png_crc_error(png_structrp png_ptr) |
| { |
| png_byte crc_bytes[4]; |
| png_uint_32 crc; |
| int need_crc = 1; |
| |
| if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name) != 0) |
| { |
| if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) == |
| (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN)) |
| need_crc = 0; |
| } |
| |
| else /* critical */ |
| { |
| if ((png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE) != 0) |
| need_crc = 0; |
| } |
| |
| #ifdef PNG_IO_STATE_SUPPORTED |
| png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_CRC; |
| #endif |
| |
| /* The chunk CRC must be serialized in a single I/O call. */ |
| png_read_data(png_ptr, crc_bytes, 4); |
| |
| if (need_crc != 0) |
| { |
| crc = png_get_uint_32(crc_bytes); |
| return ((int)(crc != png_ptr->crc)); |
| } |
| |
| else |
| return (0); |
| } |
| |
| #if defined(PNG_READ_iCCP_SUPPORTED) || defined(PNG_READ_iTXt_SUPPORTED) ||\ |
| defined(PNG_READ_pCAL_SUPPORTED) || defined(PNG_READ_sCAL_SUPPORTED) ||\ |
| defined(PNG_READ_sPLT_SUPPORTED) || defined(PNG_READ_tEXt_SUPPORTED) ||\ |
| defined(PNG_READ_zTXt_SUPPORTED) || defined(PNG_SEQUENTIAL_READ_SUPPORTED) |
| /* Manage the read buffer; this simply reallocates the buffer if it is not small |
| * enough (or if it is not allocated). The routine returns a pointer to the |
| * buffer; if an error occurs and 'warn' is set the routine returns NULL, else |
| * it will call png_error (via png_malloc) on failure. (warn == 2 means |
| * 'silent'). |
| */ |
| static png_bytep |
| png_read_buffer(png_structrp png_ptr, png_alloc_size_t new_size, int warn) |
| { |
| png_bytep buffer = png_ptr->read_buffer; |
| |
| if (buffer != NULL && new_size > png_ptr->read_buffer_size) |
| { |
| png_ptr->read_buffer = NULL; |
| png_ptr->read_buffer = NULL; |
| png_ptr->read_buffer_size = 0; |
| png_free(png_ptr, buffer); |
| buffer = NULL; |
| } |
| |
| if (buffer == NULL) |
| { |
| buffer = png_voidcast(png_bytep, png_malloc_base(png_ptr, new_size)); |
| |
| if (buffer != NULL) |
| { |
| memset(buffer, 0, new_size); /* just in case */ |
| png_ptr->read_buffer = buffer; |
| png_ptr->read_buffer_size = new_size; |
| } |
| |
| else if (warn < 2) /* else silent */ |
| { |
| if (warn != 0) |
| png_chunk_warning(png_ptr, "insufficient memory to read chunk"); |
| |
| else |
| png_chunk_error(png_ptr, "insufficient memory to read chunk"); |
| } |
| } |
| |
| return buffer; |
| } |
| #endif /* READ_iCCP|iTXt|pCAL|sCAL|sPLT|tEXt|zTXt|SEQUENTIAL_READ */ |
| |
| /* png_inflate_claim: claim the zstream for some nefarious purpose that involves |
| * decompression. Returns Z_OK on success, else a zlib error code. It checks |
| * the owner but, in final release builds, just issues a warning if some other |
| * chunk apparently owns the stream. Prior to release it does a png_error. |
| */ |
| static int |
| png_inflate_claim(png_structrp png_ptr, png_uint_32 owner) |
| { |
| if (png_ptr->zowner != 0) |
| { |
| char msg[64]; |
| |
| PNG_STRING_FROM_CHUNK(msg, png_ptr->zowner); |
| /* So the message that results is "<chunk> using zstream"; this is an |
| * internal error, but is very useful for debugging. i18n requirements |
| * are minimal. |
| */ |
| (void)png_safecat(msg, (sizeof msg), 4, " using zstream"); |
| #if PNG_RELEASE_BUILD |
| png_chunk_warning(png_ptr, msg); |
| png_ptr->zowner = 0; |
| #else |
| png_chunk_error(png_ptr, msg); |
| #endif |
| } |
| |
| /* Implementation note: unlike 'png_deflate_claim' this internal function |
| * does not take the size of the data as an argument. Some efficiency could |
| * be gained by using this when it is known *if* the zlib stream itself does |
| * not record the number; however, this is an illusion: the original writer |
| * of the PNG may have selected a lower window size, and we really must |
| * follow that because, for systems with with limited capabilities, we |
| * would otherwise reject the application's attempts to use a smaller window |
| * size (zlib doesn't have an interface to say "this or lower"!). |
| * |
| * inflateReset2 was added to zlib 1.2.4; before this the window could not be |
| * reset, therefore it is necessary to always allocate the maximum window |
| * size with earlier zlibs just in case later compressed chunks need it. |
| */ |
| { |
| int ret; /* zlib return code */ |
| #if ZLIB_VERNUM >= 0x1240 |
| int window_bits = 0; |
| |
| # if defined(PNG_SET_OPTION_SUPPORTED) && defined(PNG_MAXIMUM_INFLATE_WINDOW) |
| if (((png_ptr->options >> PNG_MAXIMUM_INFLATE_WINDOW) & 3) == |
| PNG_OPTION_ON) |
| { |
| window_bits = 15; |
| png_ptr->zstream_start = 0; /* fixed window size */ |
| } |
| |
| else |
| { |
| png_ptr->zstream_start = 1; |
| } |
| # endif |
| |
| #endif /* ZLIB_VERNUM >= 0x1240 */ |
| |
| /* Set this for safety, just in case the previous owner left pointers to |
| * memory allocations. |
| */ |
| png_ptr->zstream.next_in = NULL; |
| png_ptr->zstream.avail_in = 0; |
| png_ptr->zstream.next_out = NULL; |
| png_ptr->zstream.avail_out = 0; |
| |
| if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0) |
| { |
| #if ZLIB_VERNUM >= 0x1240 |
| ret = inflateReset2(&png_ptr->zstream, window_bits); |
| #else |
| ret = inflateReset(&png_ptr->zstream); |
| #endif |
| } |
| |
| else |
| { |
| #if ZLIB_VERNUM >= 0x1240 |
| ret = inflateInit2(&png_ptr->zstream, window_bits); |
| #else |
| ret = inflateInit(&png_ptr->zstream); |
| #endif |
| |
| if (ret == Z_OK) |
| png_ptr->flags |= PNG_FLAG_ZSTREAM_INITIALIZED; |
| } |
| |
| #if ZLIB_VERNUM >= 0x1290 && \ |
| defined(PNG_SET_OPTION_SUPPORTED) && defined(PNG_IGNORE_ADLER32) |
| if (((png_ptr->options >> PNG_IGNORE_ADLER32) & 3) == PNG_OPTION_ON) |
| /* Turn off validation of the ADLER32 checksum in IDAT chunks */ |
| ret = inflateValidate(&png_ptr->zstream, 0); |
| #endif |
| |
| if (ret == Z_OK) |
| png_ptr->zowner = owner; |
| |
| else |
| png_zstream_error(png_ptr, ret); |
| |
| return ret; |
| } |
| |
| #ifdef window_bits |
| # undef window_bits |
| #endif |
| } |
| |
| #if ZLIB_VERNUM >= 0x1240 |
| /* Handle the start of the inflate stream if we called inflateInit2(strm,0); |
| * in this case some zlib versions skip validation of the CINFO field and, in |
| * certain circumstances, libpng may end up displaying an invalid image, in |
| * contrast to implementations that call zlib in the normal way (e.g. libpng |
| * 1.5). |
| */ |
| int /* PRIVATE */ |
| png_zlib_inflate(png_structrp png_ptr, int flush) |
| { |
| if (png_ptr->zstream_start && png_ptr->zstream.avail_in > 0) |
| { |
| if ((*png_ptr->zstream.next_in >> 4) > 7) |
| { |
| png_ptr->zstream.msg = "invalid window size (libpng)"; |
| return Z_DATA_ERROR; |
| } |
| |
| png_ptr->zstream_start = 0; |
| } |
| |
| return inflate(&png_ptr->zstream, flush); |
| } |
| #endif /* Zlib >= 1.2.4 */ |
| |
| #ifdef PNG_READ_COMPRESSED_TEXT_SUPPORTED |
| #if defined(PNG_READ_zTXt_SUPPORTED) || defined (PNG_READ_iTXt_SUPPORTED) |
| /* png_inflate now returns zlib error codes including Z_OK and Z_STREAM_END to |
| * allow the caller to do multiple calls if required. If the 'finish' flag is |
| * set Z_FINISH will be passed to the final inflate() call and Z_STREAM_END must |
| * be returned or there has been a problem, otherwise Z_SYNC_FLUSH is used and |
| * Z_OK or Z_STREAM_END will be returned on success. |
| * |
| * The input and output sizes are updated to the actual amounts of data consumed |
| * or written, not the amount available (as in a z_stream). The data pointers |
| * are not changed, so the next input is (data+input_size) and the next |
| * available output is (output+output_size). |
| */ |
| static int |
| png_inflate(png_structrp png_ptr, png_uint_32 owner, int finish, |
| /* INPUT: */ png_const_bytep input, png_uint_32p input_size_ptr, |
| /* OUTPUT: */ png_bytep output, png_alloc_size_t *output_size_ptr) |
| { |
| if (png_ptr->zowner == owner) /* Else not claimed */ |
| { |
| int ret; |
| png_alloc_size_t avail_out = *output_size_ptr; |
| png_uint_32 avail_in = *input_size_ptr; |
| |
| /* zlib can't necessarily handle more than 65535 bytes at once (i.e. it |
| * can't even necessarily handle 65536 bytes) because the type uInt is |
| * "16 bits or more". Consequently it is necessary to chunk the input to |
| * zlib. This code uses ZLIB_IO_MAX, from pngpriv.h, as the maximum (the |
| * maximum value that can be stored in a uInt.) It is possible to set |
| * ZLIB_IO_MAX to a lower value in pngpriv.h and this may sometimes have |
| * a performance advantage, because it reduces the amount of data accessed |
| * at each step and that may give the OS more time to page it in. |
| */ |
| png_ptr->zstream.next_in = PNGZ_INPUT_CAST(input); |
| /* avail_in and avail_out are set below from 'size' */ |
| png_ptr->zstream.avail_in = 0; |
| png_ptr->zstream.avail_out = 0; |
| |
| /* Read directly into the output if it is available (this is set to |
| * a local buffer below if output is NULL). |
| */ |
| if (output != NULL) |
| png_ptr->zstream.next_out = output; |
| |
| do |
| { |
| uInt avail; |
| Byte local_buffer[PNG_INFLATE_BUF_SIZE]; |
| |
| /* zlib INPUT BUFFER */ |
| /* The setting of 'avail_in' used to be outside the loop; by setting it |
| * inside it is possible to chunk the input to zlib and simply rely on |
| * zlib to advance the 'next_in' pointer. This allows arbitrary |
| * amounts of data to be passed through zlib at the unavoidable cost of |
| * requiring a window save (memcpy of up to 32768 output bytes) |
| * every ZLIB_IO_MAX input bytes. |
| */ |
| avail_in += png_ptr->zstream.avail_in; /* not consumed last time */ |
| |
| avail = ZLIB_IO_MAX; |
| |
| if (avail_in < avail) |
| avail = (uInt)avail_in; /* safe: < than ZLIB_IO_MAX */ |
| |
| avail_in -= avail; |
| png_ptr->zstream.avail_in = avail; |
| |
| /* zlib OUTPUT BUFFER */ |
| avail_out += png_ptr->zstream.avail_out; /* not written last time */ |
| |
| avail = ZLIB_IO_MAX; /* maximum zlib can process */ |
| |
| if (output == NULL) |
| { |
| /* Reset the output buffer each time round if output is NULL and |
| * make available the full buffer, up to 'remaining_space' |
| */ |
| png_ptr->zstream.next_out = local_buffer; |
| if ((sizeof local_buffer) < avail) |
| avail = (sizeof local_buffer); |
| } |
| |
| if (avail_out < avail) |
| avail = (uInt)avail_out; /* safe: < ZLIB_IO_MAX */ |
| |
| png_ptr->zstream.avail_out = avail; |
| avail_out -= avail; |
| |
| /* zlib inflate call */ |
| /* In fact 'avail_out' may be 0 at this point, that happens at the end |
| * of the read when the final LZ end code was not passed at the end of |
| * the previous chunk of input data. Tell zlib if we have reached the |
| * end of the output buffer. |
| */ |
| ret = PNG_INFLATE(png_ptr, avail_out > 0 ? Z_NO_FLUSH : |
| (finish ? Z_FINISH : Z_SYNC_FLUSH)); |
| } while (ret == Z_OK); |
| |
| /* For safety kill the local buffer pointer now */ |
| if (output == NULL) |
| png_ptr->zstream.next_out = NULL; |
| |
| /* Claw back the 'size' and 'remaining_space' byte counts. */ |
| avail_in += png_ptr->zstream.avail_in; |
| avail_out += png_ptr->zstream.avail_out; |
| |
| /* Update the input and output sizes; the updated values are the amount |
| * consumed or written, effectively the inverse of what zlib uses. |
| */ |
| if (avail_out > 0) |
| *output_size_ptr -= avail_out; |
| |
| if (avail_in > 0) |
| *input_size_ptr -= avail_in; |
| |
| /* Ensure png_ptr->zstream.msg is set (even in the success case!) */ |
| png_zstream_error(png_ptr, ret); |
| return ret; |
| } |
| |
| else |
| { |
| /* This is a bad internal error. The recovery assigns to the zstream msg |
| * pointer, which is not owned by the caller, but this is safe; it's only |
| * used on errors! |
| */ |
| png_ptr->zstream.msg = PNGZ_MSG_CAST("zstream unclaimed"); |
| return Z_STREAM_ERROR; |
| } |
| } |
| |
| /* |
| * Decompress trailing data in a chunk. The assumption is that read_buffer |
| * points at an allocated area holding the contents of a chunk with a |
| * trailing compressed part. What we get back is an allocated area |
| * holding the original prefix part and an uncompressed version of the |
| * trailing part (the malloc area passed in is freed). |
| */ |
| static int |
| png_decompress_chunk(png_structrp png_ptr, |
| png_uint_32 chunklength, png_uint_32 prefix_size, |
| png_alloc_size_t *newlength /* must be initialized to the maximum! */, |
| int terminate /*add a '\0' to the end of the uncompressed data*/) |
| { |
| /* TODO: implement different limits for different types of chunk. |
| * |
| * The caller supplies *newlength set to the maximum length of the |
| * uncompressed data, but this routine allocates space for the prefix and |
| * maybe a '\0' terminator too. We have to assume that 'prefix_size' is |
| * limited only by the maximum chunk size. |
| */ |
| png_alloc_size_t limit = PNG_SIZE_MAX; |
| |
| # ifdef PNG_SET_USER_LIMITS_SUPPORTED |
| if (png_ptr->user_chunk_malloc_max > 0 && |
| png_ptr->user_chunk_malloc_max < limit) |
| limit = png_ptr->user_chunk_malloc_max; |
| # elif PNG_USER_CHUNK_MALLOC_MAX > 0 |
| if (PNG_USER_CHUNK_MALLOC_MAX < limit) |
| limit = PNG_USER_CHUNK_MALLOC_MAX; |
| # endif |
| |
| if (limit >= prefix_size + (terminate != 0)) |
| { |
| int ret; |
| |
| limit -= prefix_size + (terminate != 0); |
| |
| if (limit < *newlength) |
| *newlength = limit; |
| |
| /* Now try to claim the stream. */ |
| ret = png_inflate_claim(png_ptr, png_ptr->chunk_name); |
| |
| if (ret == Z_OK) |
| { |
| png_uint_32 lzsize = chunklength - prefix_size; |
| |
| ret = png_inflate(png_ptr, png_ptr->chunk_name, 1/*finish*/, |
| /* input: */ png_ptr->read_buffer + prefix_size, &lzsize, |
| /* output: */ NULL, newlength); |
| |
| if (ret == Z_STREAM_END) |
| { |
| /* Use 'inflateReset' here, not 'inflateReset2' because this |
| * preserves the previously decided window size (otherwise it would |
| * be necessary to store the previous window size.) In practice |
| * this doesn't matter anyway, because png_inflate will call inflate |
| * with Z_FINISH in almost all cases, so the window will not be |
| * maintained. |
| */ |
| if (inflateReset(&png_ptr->zstream) == Z_OK) |
| { |
| /* Because of the limit checks above we know that the new, |
| * expanded, size will fit in a size_t (let alone an |
| * png_alloc_size_t). Use png_malloc_base here to avoid an |
| * extra OOM message. |
| */ |
| png_alloc_size_t new_size = *newlength; |
| png_alloc_size_t buffer_size = prefix_size + new_size + |
| (terminate != 0); |
| png_bytep text = png_voidcast(png_bytep, png_malloc_base(png_ptr, |
| buffer_size)); |
| |
| if (text != NULL) |
| { |
| memset(text, 0, buffer_size); |
| |
| ret = png_inflate(png_ptr, png_ptr->chunk_name, 1/*finish*/, |
| png_ptr->read_buffer + prefix_size, &lzsize, |
| text + prefix_size, newlength); |
| |
| if (ret == Z_STREAM_END) |
| { |
| if (new_size == *newlength) |
| { |
| if (terminate != 0) |
| text[prefix_size + *newlength] = 0; |
| |
| if (prefix_size > 0) |
| memcpy(text, png_ptr->read_buffer, prefix_size); |
| |
| { |
| png_bytep old_ptr = png_ptr->read_buffer; |
| |
| png_ptr->read_buffer = text; |
| png_ptr->read_buffer_size = buffer_size; |
| text = old_ptr; /* freed below */ |
| } |
| } |
| |
| else |
| { |
| /* The size changed on the second read, there can be no |
| * guarantee that anything is correct at this point. |
| * The 'msg' pointer has been set to "unexpected end of |
| * LZ stream", which is fine, but return an error code |
| * that the caller won't accept. |
| */ |
| ret = PNG_UNEXPECTED_ZLIB_RETURN; |
| } |
| } |
| |
| else if (ret == Z_OK) |
| ret = PNG_UNEXPECTED_ZLIB_RETURN; /* for safety */ |
| |
| /* Free the text pointer (this is the old read_buffer on |
| * success) |
| */ |
| png_free(png_ptr, text); |
| |
| /* This really is very benign, but it's still an error because |
| * the extra space may otherwise be used as a Trojan Horse. |
| */ |
| if (ret == Z_STREAM_END && |
| chunklength - prefix_size != lzsize) |
| png_chunk_benign_error(png_ptr, "extra compressed data"); |
| } |
| |
| else |
| { |
| /* Out of memory allocating the buffer */ |
| ret = Z_MEM_ERROR; |
| png_zstream_error(png_ptr, Z_MEM_ERROR); |
| } |
| } |
| |
| else |
| { |
| /* inflateReset failed, store the error message */ |
| png_zstream_error(png_ptr, ret); |
| ret = PNG_UNEXPECTED_ZLIB_RETURN; |
| } |
| } |
| |
| else if (ret == Z_OK) |
| ret = PNG_UNEXPECTED_ZLIB_RETURN; |
| |
| /* Release the claimed stream */ |
| png_ptr->zowner = 0; |
| } |
| |
| else /* the claim failed */ if (ret == Z_STREAM_END) /* impossible! */ |
| ret = PNG_UNEXPECTED_ZLIB_RETURN; |
| |
| return ret; |
| } |
| |
| else |
| { |
| /* Application/configuration limits exceeded */ |
| png_zstream_error(png_ptr, Z_MEM_ERROR); |
| return Z_MEM_ERROR; |
| } |
| } |
| #endif /* READ_zTXt || READ_iTXt */ |
| #endif /* READ_COMPRESSED_TEXT */ |
| |
| #ifdef PNG_READ_iCCP_SUPPORTED |
| /* Perform a partial read and decompress, producing 'avail_out' bytes and |
| * reading from the current chunk as required. |
| */ |
| static int |
| png_inflate_read(png_structrp png_ptr, png_bytep read_buffer, uInt read_size, |
| png_uint_32p chunk_bytes, png_bytep next_out, png_alloc_size_t *out_size, |
| int finish) |
| { |
| if (png_ptr->zowner == png_ptr->chunk_name) |
| { |
| int ret; |
| |
| /* next_in and avail_in must have been initialized by the caller. */ |
| png_ptr->zstream.next_out = next_out; |
| png_ptr->zstream.avail_out = 0; /* set in the loop */ |
| |
| do |
| { |
| if (png_ptr->zstream.avail_in == 0) |
| { |
| if (read_size > *chunk_bytes) |
| read_size = (uInt)*chunk_bytes; |
| *chunk_bytes -= read_size; |
| |
| if (read_size > 0) |
| png_crc_read(png_ptr, read_buffer, read_size); |
| |
| png_ptr->zstream.next_in = read_buffer; |
| png_ptr->zstream.avail_in = read_size; |
| } |
| |
| if (png_ptr->zstream.avail_out == 0) |
| { |
| uInt avail = ZLIB_IO_MAX; |
| if (avail > *out_size) |
| avail = (uInt)*out_size; |
| *out_size -= avail; |
| |
| png_ptr->zstream.avail_out = avail; |
| } |
| |
| /* Use Z_SYNC_FLUSH when there is no more chunk data to ensure that all |
| * the available output is produced; this allows reading of truncated |
| * streams. |
| */ |
| ret = PNG_INFLATE(png_ptr, *chunk_bytes > 0 ? |
| Z_NO_FLUSH : (finish ? Z_FINISH : Z_SYNC_FLUSH)); |
| } |
| while (ret == Z_OK && (*out_size > 0 || png_ptr->zstream.avail_out > 0)); |
| |
| *out_size += png_ptr->zstream.avail_out; |
| png_ptr->zstream.avail_out = 0; /* Should not be required, but is safe */ |
| |
| /* Ensure the error message pointer is always set: */ |
| png_zstream_error(png_ptr, ret); |
| return ret; |
| } |
| |
| else |
| { |
| png_ptr->zstream.msg = PNGZ_MSG_CAST("zstream unclaimed"); |
| return Z_STREAM_ERROR; |
| } |
| } |
| #endif /* READ_iCCP */ |
| |
| /* Read and check the IDHR chunk */ |
| |
| void /* PRIVATE */ |
| png_handle_IHDR(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) |
| { |
| png_byte buf[13]; |
| png_uint_32 width, height; |
| int bit_depth, color_type, compression_type, filter_type; |
| int interlace_type; |
| |
| png_debug(1, "in png_handle_IHDR"); |
| |
| if ((png_ptr->mode & PNG_HAVE_IHDR) != 0) |
| png_chunk_error(png_ptr, "out of place"); |
| |
| /* Check the length */ |
| if (length != 13) |
| png_chunk_error(png_ptr, "invalid"); |
| |
| png_ptr->mode |= PNG_HAVE_IHDR; |
| |
| png_crc_read(png_ptr, buf, 13); |
| png_crc_finish(png_ptr, 0); |
| |
| width = png_get_uint_31(png_ptr, buf); |
| height = png_get_uint_31(png_ptr, buf + 4); |
| bit_depth = buf[8]; |
| color_type = buf[9]; |
| compression_type = buf[10]; |
| filter_type = buf[11]; |
| interlace_type = buf[12]; |
| |
| /* Set internal variables */ |
| png_ptr->width = width; |
| png_ptr->height = height; |
| png_ptr->bit_depth = (png_byte)bit_depth; |
| png_ptr->interlaced = (png_byte)interlace_type; |
| png_ptr->color_type = (png_byte)color_type; |
| #ifdef PNG_MNG_FEATURES_SUPPORTED |
| png_ptr->filter_type = (png_byte)filter_type; |
| #endif |
| png_ptr->compression_type = (png_byte)compression_type; |
| |
| /* Find number of channels */ |
| switch (png_ptr->color_type) |
| { |
| default: /* invalid, png_set_IHDR calls png_error */ |
| case PNG_COLOR_TYPE_GRAY: |
| case PNG_COLOR_TYPE_PALETTE: |
| png_ptr->channels = 1; |
| break; |
| |
| case PNG_COLOR_TYPE_RGB: |
| png_ptr->channels = 3; |
| break; |
| |
| case PNG_COLOR_TYPE_GRAY_ALPHA: |
| png_ptr->channels = 2; |
| break; |
| |
| case PNG_COLOR_TYPE_RGB_ALPHA: |
| png_ptr->channels = 4; |
| break; |
| } |
| |
| /* Set up other useful info */ |
| png_ptr->pixel_depth = (png_byte)(png_ptr->bit_depth * png_ptr->channels); |
| png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->width); |
| png_debug1(3, "bit_depth = %d", png_ptr->bit_depth); |
| png_debug1(3, "channels = %d", png_ptr->channels); |
| png_debug1(3, "rowbytes = %lu", (unsigned long)png_ptr->rowbytes); |
| png_set_IHDR(png_ptr, info_ptr, width, height, bit_depth, |
| color_type, interlace_type, compression_type, filter_type); |
| } |
| |
| /* Read and check the palette */ |
| void /* PRIVATE */ |
| png_handle_PLTE(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) |
| { |
| png_color palette[PNG_MAX_PALETTE_LENGTH]; |
| int max_palette_length, num, i; |
| #ifdef PNG_POINTER_INDEXING_SUPPORTED |
| png_colorp pal_ptr; |
| #endif |
| |
| png_debug(1, "in png_handle_PLTE"); |
| |
| if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) |
| png_chunk_error(png_ptr, "missing IHDR"); |
| |
| /* Moved to before the 'after IDAT' check below because otherwise duplicate |
| * PLTE chunks are potentially ignored (the spec says there shall not be more |
| * than one PLTE, the error is not treated as benign, so this check trumps |
| * the requirement that PLTE appears before IDAT.) |
| */ |
| else if ((png_ptr->mode & PNG_HAVE_PLTE) != 0) |
| png_chunk_error(png_ptr, "duplicate"); |
| |
| else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) |
| { |
| /* This is benign because the non-benign error happened before, when an |
| * IDAT was encountered in a color-mapped image with no PLTE. |
| */ |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "out of place"); |
| return; |
| } |
| |
| png_ptr->mode |= PNG_HAVE_PLTE; |
| |
| if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "ignored in grayscale PNG"); |
| return; |
| } |
| |
| #ifndef PNG_READ_OPT_PLTE_SUPPORTED |
| if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE) |
| { |
| png_crc_finish(png_ptr, length); |
| return; |
| } |
| #endif |
| |
| if (length > 3*PNG_MAX_PALETTE_LENGTH || length % 3) |
| { |
| png_crc_finish(png_ptr, length); |
| |
| if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE) |
| png_chunk_benign_error(png_ptr, "invalid"); |
| |
| else |
| png_chunk_error(png_ptr, "invalid"); |
| |
| return; |
| } |
| |
| /* The cast is safe because 'length' is less than 3*PNG_MAX_PALETTE_LENGTH */ |
| num = (int)length / 3; |
| |
| /* If the palette has 256 or fewer entries but is too large for the bit |
| * depth, we don't issue an error, to preserve the behavior of previous |
| * libpng versions. We silently truncate the unused extra palette entries |
| * here. |
| */ |
| if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) |
| max_palette_length = (1 << png_ptr->bit_depth); |
| else |
| max_palette_length = PNG_MAX_PALETTE_LENGTH; |
| |
| if (num > max_palette_length) |
| num = max_palette_length; |
| |
| #ifdef PNG_POINTER_INDEXING_SUPPORTED |
| for (i = 0, pal_ptr = palette; i < num; i++, pal_ptr++) |
| { |
| png_byte buf[3]; |
| |
| png_crc_read(png_ptr, buf, 3); |
| pal_ptr->red = buf[0]; |
| pal_ptr->green = buf[1]; |
| pal_ptr->blue = buf[2]; |
| } |
| #else |
| for (i = 0; i < num; i++) |
| { |
| png_byte buf[3]; |
| |
| png_crc_read(png_ptr, buf, 3); |
| /* Don't depend upon png_color being any order */ |
| palette[i].red = buf[0]; |
| palette[i].green = buf[1]; |
| palette[i].blue = buf[2]; |
| } |
| #endif |
| |
| /* If we actually need the PLTE chunk (ie for a paletted image), we do |
| * whatever the normal CRC configuration tells us. However, if we |
| * have an RGB image, the PLTE can be considered ancillary, so |
| * we will act as though it is. |
| */ |
| #ifndef PNG_READ_OPT_PLTE_SUPPORTED |
| if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) |
| #endif |
| { |
| png_crc_finish(png_ptr, (png_uint_32) (length - (unsigned int)num * 3)); |
| } |
| |
| #ifndef PNG_READ_OPT_PLTE_SUPPORTED |
| else if (png_crc_error(png_ptr) != 0) /* Only if we have a CRC error */ |
| { |
| /* If we don't want to use the data from an ancillary chunk, |
| * we have two options: an error abort, or a warning and we |
| * ignore the data in this chunk (which should be OK, since |
| * it's considered ancillary for a RGB or RGBA image). |
| * |
| * IMPLEMENTATION NOTE: this is only here because png_crc_finish uses the |
| * chunk type to determine whether to check the ancillary or the critical |
| * flags. |
| */ |
| if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_USE) == 0) |
| { |
| if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) != 0) |
| return; |
| |
| else |
| png_chunk_error(png_ptr, "CRC error"); |
| } |
| |
| /* Otherwise, we (optionally) emit a warning and use the chunk. */ |
| else if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) == 0) |
| png_chunk_warning(png_ptr, "CRC error"); |
| } |
| #endif |
| |
| /* TODO: png_set_PLTE has the side effect of setting png_ptr->palette to its |
| * own copy of the palette. This has the side effect that when png_start_row |
| * is called (this happens after any call to png_read_update_info) the |
| * info_ptr palette gets changed. This is extremely unexpected and |
| * confusing. |
| * |
| * Fix this by not sharing the palette in this way. |
| */ |
| png_set_PLTE(png_ptr, info_ptr, palette, num); |
| |
| /* The three chunks, bKGD, hIST and tRNS *must* appear after PLTE and before |
| * IDAT. Prior to 1.6.0 this was not checked; instead the code merely |
| * checked the apparent validity of a tRNS chunk inserted before PLTE on a |
| * palette PNG. 1.6.0 attempts to rigorously follow the standard and |
| * therefore does a benign error if the erroneous condition is detected *and* |
| * cancels the tRNS if the benign error returns. The alternative is to |
| * amend the standard since it would be rather hypocritical of the standards |
| * maintainers to ignore it. |
| */ |
| #ifdef PNG_READ_tRNS_SUPPORTED |
| if (png_ptr->num_trans > 0 || |
| (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS) != 0)) |
| { |
| /* Cancel this because otherwise it would be used if the transforms |
| * require it. Don't cancel the 'valid' flag because this would prevent |
| * detection of duplicate chunks. |
| */ |
| png_ptr->num_trans = 0; |
| |
| if (info_ptr != NULL) |
| info_ptr->num_trans = 0; |
| |
| png_chunk_benign_error(png_ptr, "tRNS must be after"); |
| } |
| #endif |
| |
| #ifdef PNG_READ_hIST_SUPPORTED |
| if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST) != 0) |
| png_chunk_benign_error(png_ptr, "hIST must be after"); |
| #endif |
| |
| #ifdef PNG_READ_bKGD_SUPPORTED |
| if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD) != 0) |
| png_chunk_benign_error(png_ptr, "bKGD must be after"); |
| #endif |
| } |
| |
| void /* PRIVATE */ |
| png_handle_IEND(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) |
| { |
| png_debug(1, "in png_handle_IEND"); |
| |
| if ((png_ptr->mode & PNG_HAVE_IHDR) == 0 || |
| (png_ptr->mode & PNG_HAVE_IDAT) == 0) |
| png_chunk_error(png_ptr, "out of place"); |
| |
| png_ptr->mode |= (PNG_AFTER_IDAT | PNG_HAVE_IEND); |
| |
| png_crc_finish(png_ptr, length); |
| |
| if (length != 0) |
| png_chunk_benign_error(png_ptr, "invalid"); |
| |
| PNG_UNUSED(info_ptr) |
| } |
| |
| #ifdef PNG_READ_gAMA_SUPPORTED |
| void /* PRIVATE */ |
| png_handle_gAMA(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) |
| { |
| png_fixed_point igamma; |
| png_byte buf[4]; |
| |
| png_debug(1, "in png_handle_gAMA"); |
| |
| if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) |
| png_chunk_error(png_ptr, "missing IHDR"); |
| |
| else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "out of place"); |
| return; |
| } |
| |
| if (length != 4) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "invalid"); |
| return; |
| } |
| |
| png_crc_read(png_ptr, buf, 4); |
| |
| if (png_crc_finish(png_ptr, 0) != 0) |
| return; |
| |
| igamma = png_get_fixed_point(NULL, buf); |
| |
| png_colorspace_set_gamma(png_ptr, &png_ptr->colorspace, igamma); |
| png_colorspace_sync(png_ptr, info_ptr); |
| } |
| #endif |
| |
| #ifdef PNG_READ_sBIT_SUPPORTED |
| void /* PRIVATE */ |
| png_handle_sBIT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) |
| { |
| unsigned int truelen, i; |
| png_byte sample_depth; |
| png_byte buf[4]; |
| |
| png_debug(1, "in png_handle_sBIT"); |
| |
| if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) |
| png_chunk_error(png_ptr, "missing IHDR"); |
| |
| else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "out of place"); |
| return; |
| } |
| |
| if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sBIT) != 0) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "duplicate"); |
| return; |
| } |
| |
| if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) |
| { |
| truelen = 3; |
| sample_depth = 8; |
| } |
| |
| else |
| { |
| truelen = png_ptr->channels; |
| sample_depth = png_ptr->bit_depth; |
| } |
| |
| if (length != truelen || length > 4) |
| { |
| png_chunk_benign_error(png_ptr, "invalid"); |
| png_crc_finish(png_ptr, length); |
| return; |
| } |
| |
| buf[0] = buf[1] = buf[2] = buf[3] = sample_depth; |
| png_crc_read(png_ptr, buf, truelen); |
| |
| if (png_crc_finish(png_ptr, 0) != 0) |
| return; |
| |
| for (i=0; i<truelen; ++i) |
| { |
| if (buf[i] == 0 || buf[i] > sample_depth) |
| { |
| png_chunk_benign_error(png_ptr, "invalid"); |
| return; |
| } |
| } |
| |
| if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0) |
| { |
| png_ptr->sig_bit.red = buf[0]; |
| png_ptr->sig_bit.green = buf[1]; |
| png_ptr->sig_bit.blue = buf[2]; |
| png_ptr->sig_bit.alpha = buf[3]; |
| } |
| |
| else |
| { |
| png_ptr->sig_bit.gray = buf[0]; |
| png_ptr->sig_bit.red = buf[0]; |
| png_ptr->sig_bit.green = buf[0]; |
| png_ptr->sig_bit.blue = buf[0]; |
| png_ptr->sig_bit.alpha = buf[1]; |
| } |
| |
| png_set_sBIT(png_ptr, info_ptr, &(png_ptr->sig_bit)); |
| } |
| #endif |
| |
| #ifdef PNG_READ_cHRM_SUPPORTED |
| void /* PRIVATE */ |
| png_handle_cHRM(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) |
| { |
| png_byte buf[32]; |
| png_xy xy; |
| |
| png_debug(1, "in png_handle_cHRM"); |
| |
| if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) |
| png_chunk_error(png_ptr, "missing IHDR"); |
| |
| else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "out of place"); |
| return; |
| } |
| |
| if (length != 32) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "invalid"); |
| return; |
| } |
| |
| png_crc_read(png_ptr, buf, 32); |
| |
| if (png_crc_finish(png_ptr, 0) != 0) |
| return; |
| |
| xy.whitex = png_get_fixed_point(NULL, buf); |
| xy.whitey = png_get_fixed_point(NULL, buf + 4); |
| xy.redx = png_get_fixed_point(NULL, buf + 8); |
| xy.redy = png_get_fixed_point(NULL, buf + 12); |
| xy.greenx = png_get_fixed_point(NULL, buf + 16); |
| xy.greeny = png_get_fixed_point(NULL, buf + 20); |
| xy.bluex = png_get_fixed_point(NULL, buf + 24); |
| xy.bluey = png_get_fixed_point(NULL, buf + 28); |
| |
| if (xy.whitex == PNG_FIXED_ERROR || |
| xy.whitey == PNG_FIXED_ERROR || |
| xy.redx == PNG_FIXED_ERROR || |
| xy.redy == PNG_FIXED_ERROR || |
| xy.greenx == PNG_FIXED_ERROR || |
| xy.greeny == PNG_FIXED_ERROR || |
| xy.bluex == PNG_FIXED_ERROR || |
| xy.bluey == PNG_FIXED_ERROR) |
| { |
| png_chunk_benign_error(png_ptr, "invalid values"); |
| return; |
| } |
| |
| /* If a colorspace error has already been output skip this chunk */ |
| if ((png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0) |
| return; |
| |
| if ((png_ptr->colorspace.flags & PNG_COLORSPACE_FROM_cHRM) != 0) |
| { |
| png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID; |
| png_colorspace_sync(png_ptr, info_ptr); |
| png_chunk_benign_error(png_ptr, "duplicate"); |
| return; |
| } |
| |
| png_ptr->colorspace.flags |= PNG_COLORSPACE_FROM_cHRM; |
| (void)png_colorspace_set_chromaticities(png_ptr, &png_ptr->colorspace, &xy, |
| 1/*prefer cHRM values*/); |
| png_colorspace_sync(png_ptr, info_ptr); |
| } |
| #endif |
| |
| #ifdef PNG_READ_sRGB_SUPPORTED |
| void /* PRIVATE */ |
| png_handle_sRGB(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) |
| { |
| png_byte intent; |
| |
| png_debug(1, "in png_handle_sRGB"); |
| |
| if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) |
| png_chunk_error(png_ptr, "missing IHDR"); |
| |
| else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "out of place"); |
| return; |
| } |
| |
| if (length != 1) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "invalid"); |
| return; |
| } |
| |
| png_crc_read(png_ptr, &intent, 1); |
| |
| if (png_crc_finish(png_ptr, 0) != 0) |
| return; |
| |
| /* If a colorspace error has already been output skip this chunk */ |
| if ((png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0) |
| return; |
| |
| /* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect |
| * this. |
| */ |
| if ((png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_INTENT) != 0) |
| { |
| png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID; |
| png_colorspace_sync(png_ptr, info_ptr); |
| png_chunk_benign_error(png_ptr, "too many profiles"); |
| return; |
| } |
| |
| (void)png_colorspace_set_sRGB(png_ptr, &png_ptr->colorspace, intent); |
| png_colorspace_sync(png_ptr, info_ptr); |
| } |
| #endif /* READ_sRGB */ |
| |
| #ifdef PNG_READ_iCCP_SUPPORTED |
| void /* PRIVATE */ |
| png_handle_iCCP(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) |
| /* Note: this does not properly handle profiles that are > 64K under DOS */ |
| { |
| png_const_charp errmsg = NULL; /* error message output, or no error */ |
| int finished = 0; /* crc checked */ |
| |
| png_debug(1, "in png_handle_iCCP"); |
| |
| if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) |
| png_chunk_error(png_ptr, "missing IHDR"); |
| |
| else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "out of place"); |
| return; |
| } |
| |
| /* Consistent with all the above colorspace handling an obviously *invalid* |
| * chunk is just ignored, so does not invalidate the color space. An |
| * alternative is to set the 'invalid' flags at the start of this routine |
| * and only clear them in they were not set before and all the tests pass. |
| */ |
| |
| /* The keyword must be at least one character and there is a |
| * terminator (0) byte and the compression method byte, and the |
| * 'zlib' datastream is at least 11 bytes. |
| */ |
| if (length < 14) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "too short"); |
| return; |
| } |
| |
| /* If a colorspace error has already been output skip this chunk */ |
| if ((png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0) |
| { |
| png_crc_finish(png_ptr, length); |
| return; |
| } |
| |
| /* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect |
| * this. |
| */ |
| if ((png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_INTENT) == 0) |
| { |
| uInt read_length, keyword_length; |
| char keyword[81]; |
| |
| /* Find the keyword; the keyword plus separator and compression method |
| * bytes can be at most 81 characters long. |
| */ |
| read_length = 81; /* maximum */ |
| if (read_length > length) |
| read_length = (uInt)length; |
| |
| png_crc_read(png_ptr, (png_bytep)keyword, read_length); |
| length -= read_length; |
| |
| /* The minimum 'zlib' stream is assumed to be just the 2 byte header, |
| * 5 bytes minimum 'deflate' stream, and the 4 byte checksum. |
| */ |
| if (length < 11) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "too short"); |
| return; |
| } |
| |
| keyword_length = 0; |
| while (keyword_length < 80 && keyword_length < read_length && |
| keyword[keyword_length] != 0) |
| ++keyword_length; |
| |
| /* TODO: make the keyword checking common */ |
| if (keyword_length >= 1 && keyword_length <= 79) |
| { |
| /* We only understand '0' compression - deflate - so if we get a |
| * different value we can't safely decode the chunk. |
| */ |
| if (keyword_length+1 < read_length && |
| keyword[keyword_length+1] == PNG_COMPRESSION_TYPE_BASE) |
| { |
| read_length -= keyword_length+2; |
| |
| if (png_inflate_claim(png_ptr, png_iCCP) == Z_OK) |
| { |
| Byte profile_header[132]={0}; |
| Byte local_buffer[PNG_INFLATE_BUF_SIZE]; |
| png_alloc_size_t size = (sizeof profile_header); |
| |
| png_ptr->zstream.next_in = (Bytef*)keyword + (keyword_length+2); |
| png_ptr->zstream.avail_in = read_length; |
| (void)png_inflate_read(png_ptr, local_buffer, |
| (sizeof local_buffer), &length, profile_header, &size, |
| 0/*finish: don't, because the output is too small*/); |
| |
| if (size == 0) |
| { |
| /* We have the ICC profile header; do the basic header checks. |
| */ |
| png_uint_32 profile_length = png_get_uint_32(profile_header); |
| |
| if (png_icc_check_length(png_ptr, &png_ptr->colorspace, |
| keyword, profile_length) != 0) |
| { |
| /* The length is apparently ok, so we can check the 132 |
| * byte header. |
| */ |
| if (png_icc_check_header(png_ptr, &png_ptr->colorspace, |
| keyword, profile_length, profile_header, |
| png_ptr->color_type) != 0) |
| { |
| /* Now read the tag table; a variable size buffer is |
| * needed at this point, allocate one for the whole |
| * profile. The header check has already validated |
| * that none of this stuff will overflow. |
| */ |
| png_uint_32 tag_count = |
| png_get_uint_32(profile_header + 128); |
| png_bytep profile = png_read_buffer(png_ptr, |
| profile_length, 2/*silent*/); |
| |
| if (profile != NULL) |
| { |
| memcpy(profile, profile_header, |
| (sizeof profile_header)); |
| |
| size = 12 * tag_count; |
| |
| (void)png_inflate_read(png_ptr, local_buffer, |
| (sizeof local_buffer), &length, |
| profile + (sizeof profile_header), &size, 0); |
| |
| /* Still expect a buffer error because we expect |
| * there to be some tag data! |
| */ |
| if (size == 0) |
| { |
| if (png_icc_check_tag_table(png_ptr, |
| &png_ptr->colorspace, keyword, profile_length, |
| profile) != 0) |
| { |
| /* The profile has been validated for basic |
| * security issues, so read the whole thing in. |
| */ |
| size = profile_length - (sizeof profile_header) |
| - 12 * tag_count; |
| |
| (void)png_inflate_read(png_ptr, local_buffer, |
| (sizeof local_buffer), &length, |
| profile + (sizeof profile_header) + |
| 12 * tag_count, &size, 1/*finish*/); |
| |
| if (length > 0 && !(png_ptr->flags & |
| PNG_FLAG_BENIGN_ERRORS_WARN)) |
| errmsg = "extra compressed data"; |
| |
| /* But otherwise allow extra data: */ |
| else if (size == 0) |
| { |
| if (length > 0) |
| { |
| /* This can be handled completely, so |
| * keep going. |
| */ |
| png_chunk_warning(png_ptr, |
| "extra compressed data"); |
| } |
| |
| png_crc_finish(png_ptr, length); |
| finished = 1; |
| |
| # if defined(PNG_sRGB_SUPPORTED) && PNG_sRGB_PROFILE_CHECKS >= 0 |
| /* Check for a match against sRGB */ |
| png_icc_set_sRGB(png_ptr, |
| &png_ptr->colorspace, profile, |
| png_ptr->zstream.adler); |
| # endif |
| |
| /* Steal the profile for info_ptr. */ |
| if (info_ptr != NULL) |
| { |
| png_free_data(png_ptr, info_ptr, |
| PNG_FREE_ICCP, 0); |
| |
| info_ptr->iccp_name = png_voidcast(char*, |
| png_malloc_base(png_ptr, |
| keyword_length+1)); |
| if (info_ptr->iccp_name != NULL) |
| { |
| memcpy(info_ptr->iccp_name, keyword, |
| keyword_length+1); |
| info_ptr->iccp_proflen = |
| profile_length; |
| info_ptr->iccp_profile = profile; |
| png_ptr->read_buffer = NULL; /*steal*/ |
| info_ptr->free_me |= PNG_FREE_ICCP; |
| info_ptr->valid |= PNG_INFO_iCCP; |
| } |
| |
| else |
| { |
| png_ptr->colorspace.flags |= |
| PNG_COLORSPACE_INVALID; |
| errmsg = "out of memory"; |
| } |
| } |
| |
| /* else the profile remains in the read |
| * buffer which gets reused for subsequent |
| * chunks. |
| */ |
| |
| if (info_ptr != NULL) |
| png_colorspace_sync(png_ptr, info_ptr); |
| |
| if (errmsg == NULL) |
| { |
| png_ptr->zowner = 0; |
| return; |
| } |
| } |
| if (errmsg == NULL) |
| errmsg = png_ptr->zstream.msg; |
| } |
| /* else png_icc_check_tag_table output an error */ |
| } |
| else /* profile truncated */ |
| errmsg = png_ptr->zstream.msg; |
| } |
| |
| else |
| errmsg = "out of memory"; |
| } |
| |
| /* else png_icc_check_header output an error */ |
| } |
| |
| /* else png_icc_check_length output an error */ |
| } |
| |
| else /* profile truncated */ |
| errmsg = png_ptr->zstream.msg; |
| |
| /* Release the stream */ |
| png_ptr->zowner = 0; |
| } |
| |
| else /* png_inflate_claim failed */ |
| errmsg = png_ptr->zstream.msg; |
| } |
| |
| else |
| errmsg = "bad compression method"; /* or missing */ |
| } |
| |
| else |
| errmsg = "bad keyword"; |
| } |
| |
| else |
| errmsg = "too many profiles"; |
| |
| /* Failure: the reason is in 'errmsg' */ |
| if (finished == 0) |
| png_crc_finish(png_ptr, length); |
| |
| png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID; |
| png_colorspace_sync(png_ptr, info_ptr); |
| if (errmsg != NULL) /* else already output */ |
| png_chunk_benign_error(png_ptr, errmsg); |
| } |
| #endif /* READ_iCCP */ |
| |
| #ifdef PNG_READ_sPLT_SUPPORTED |
| void /* PRIVATE */ |
| png_handle_sPLT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) |
| /* Note: this does not properly handle chunks that are > 64K under DOS */ |
| { |
| png_bytep entry_start, buffer; |
| png_sPLT_t new_palette; |
| png_sPLT_entryp pp; |
| png_uint_32 data_length; |
| int entry_size, i; |
| png_uint_32 skip = 0; |
| png_uint_32 dl; |
| size_t max_dl; |
| |
| png_debug(1, "in png_handle_sPLT"); |
| |
| #ifdef PNG_USER_LIMITS_SUPPORTED |
| if (png_ptr->user_chunk_cache_max != 0) |
| { |
| if (png_ptr->user_chunk_cache_max == 1) |
| { |
| png_crc_finish(png_ptr, length); |
| return; |
| } |
| |
| if (--png_ptr->user_chunk_cache_max == 1) |
| { |
| png_warning(png_ptr, "No space in chunk cache for sPLT"); |
| png_crc_finish(png_ptr, length); |
| return; |
| } |
| } |
| #endif |
| |
| if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) |
| png_chunk_error(png_ptr, "missing IHDR"); |
| |
| else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "out of place"); |
| return; |
| } |
| |
| #ifdef PNG_MAX_MALLOC_64K |
| if (length > 65535U) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "too large to fit in memory"); |
| return; |
| } |
| #endif |
| |
| buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/); |
| if (buffer == NULL) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "out of memory"); |
| return; |
| } |
| |
| |
| /* WARNING: this may break if size_t is less than 32 bits; it is assumed |
| * that the PNG_MAX_MALLOC_64K test is enabled in this case, but this is a |
| * potential breakage point if the types in pngconf.h aren't exactly right. |
| */ |
| png_crc_read(png_ptr, buffer, length); |
| |
| if (png_crc_finish(png_ptr, skip) != 0) |
| return; |
| |
| buffer[length] = 0; |
| |
| for (entry_start = buffer; *entry_start; entry_start++) |
| /* Empty loop to find end of name */ ; |
| |
| ++entry_start; |
| |
| /* A sample depth should follow the separator, and we should be on it */ |
| if (length < 2U || entry_start > buffer + (length - 2U)) |
| { |
| png_warning(png_ptr, "malformed sPLT chunk"); |
| return; |
| } |
| |
| new_palette.depth = *entry_start++; |
| entry_size = (new_palette.depth == 8 ? 6 : 10); |
| /* This must fit in a png_uint_32 because it is derived from the original |
| * chunk data length. |
| */ |
| data_length = length - (png_uint_32)(entry_start - buffer); |
| |
| /* Integrity-check the data length */ |
| if ((data_length % (unsigned int)entry_size) != 0) |
| { |
| png_warning(png_ptr, "sPLT chunk has bad length"); |
| return; |
| } |
| |
| dl = (png_uint_32)(data_length / (unsigned int)entry_size); |
| max_dl = PNG_SIZE_MAX / (sizeof (png_sPLT_entry)); |
| |
| if (dl > max_dl) |
| { |
| png_warning(png_ptr, "sPLT chunk too long"); |
| return; |
| } |
| |
| new_palette.nentries = (png_int_32)(data_length / (unsigned int)entry_size); |
| |
| new_palette.entries = (png_sPLT_entryp)png_malloc_warn(png_ptr, |
| (png_alloc_size_t) new_palette.nentries * (sizeof (png_sPLT_entry))); |
| |
| if (new_palette.entries == NULL) |
| { |
| png_warning(png_ptr, "sPLT chunk requires too much memory"); |
| return; |
| } |
| |
| #ifdef PNG_POINTER_INDEXING_SUPPORTED |
| for (i = 0; i < new_palette.nentries; i++) |
| { |
| pp = new_palette.entries + i; |
| |
| if (new_palette.depth == 8) |
| { |
| pp->red = *entry_start++; |
| pp->green = *entry_start++; |
| pp->blue = *entry_start++; |
| pp->alpha = *entry_start++; |
| } |
| |
| else |
| { |
| pp->red = png_get_uint_16(entry_start); entry_start += 2; |
| pp->green = png_get_uint_16(entry_start); entry_start += 2; |
| pp->blue = png_get_uint_16(entry_start); entry_start += 2; |
| pp->alpha = png_get_uint_16(entry_start); entry_start += 2; |
| } |
| |
| pp->frequency = png_get_uint_16(entry_start); entry_start += 2; |
| } |
| #else |
| pp = new_palette.entries; |
| |
| for (i = 0; i < new_palette.nentries; i++) |
| { |
| |
| if (new_palette.depth == 8) |
| { |
| pp[i].red = *entry_start++; |
| pp[i].green = *entry_start++; |
| pp[i].blue = *entry_start++; |
| pp[i].alpha = *entry_start++; |
| } |
| |
| else |
| { |
| pp[i].red = png_get_uint_16(entry_start); entry_start += 2; |
| pp[i].green = png_get_uint_16(entry_start); entry_start += 2; |
| pp[i].blue = png_get_uint_16(entry_start); entry_start += 2; |
| pp[i].alpha = png_get_uint_16(entry_start); entry_start += 2; |
| } |
| |
| pp[i].frequency = png_get_uint_16(entry_start); entry_start += 2; |
| } |
| #endif |
| |
| /* Discard all chunk data except the name and stash that */ |
| new_palette.name = (png_charp)buffer; |
| |
| png_set_sPLT(png_ptr, info_ptr, &new_palette, 1); |
| |
| png_free(png_ptr, new_palette.entries); |
| } |
| #endif /* READ_sPLT */ |
| |
| #ifdef PNG_READ_tRNS_SUPPORTED |
| void /* PRIVATE */ |
| png_handle_tRNS(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) |
| { |
| png_byte readbuf[PNG_MAX_PALETTE_LENGTH]; |
| |
| png_debug(1, "in png_handle_tRNS"); |
| |
| if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) |
| png_chunk_error(png_ptr, "missing IHDR"); |
| |
| else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "out of place"); |
| return; |
| } |
| |
| else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS) != 0) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "duplicate"); |
| return; |
| } |
| |
| if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY) |
| { |
| png_byte buf[2]; |
| |
| if (length != 2) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "invalid"); |
| return; |
| } |
| |
| png_crc_read(png_ptr, buf, 2); |
| png_ptr->num_trans = 1; |
| png_ptr->trans_color.gray = png_get_uint_16(buf); |
| } |
| |
| else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB) |
| { |
| png_byte buf[6]; |
| |
| if (length != 6) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "invalid"); |
| return; |
| } |
| |
| png_crc_read(png_ptr, buf, length); |
| png_ptr->num_trans = 1; |
| png_ptr->trans_color.red = png_get_uint_16(buf); |
| png_ptr->trans_color.green = png_get_uint_16(buf + 2); |
| png_ptr->trans_color.blue = png_get_uint_16(buf + 4); |
| } |
| |
| else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) |
| { |
| if ((png_ptr->mode & PNG_HAVE_PLTE) == 0) |
| { |
| /* TODO: is this actually an error in the ISO spec? */ |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "out of place"); |
| return; |
| } |
| |
| if (length > (unsigned int) png_ptr->num_palette || |
| length > (unsigned int) PNG_MAX_PALETTE_LENGTH || |
| length == 0) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "invalid"); |
| return; |
| } |
| |
| png_crc_read(png_ptr, readbuf, length); |
| png_ptr->num_trans = (png_uint_16)length; |
| } |
| |
| else |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "invalid with alpha channel"); |
| return; |
| } |
| |
| if (png_crc_finish(png_ptr, 0) != 0) |
| { |
| png_ptr->num_trans = 0; |
| return; |
| } |
| |
| /* TODO: this is a horrible side effect in the palette case because the |
| * png_struct ends up with a pointer to the tRNS buffer owned by the |
| * png_info. Fix this. |
| */ |
| png_set_tRNS(png_ptr, info_ptr, readbuf, png_ptr->num_trans, |
| &(png_ptr->trans_color)); |
| } |
| #endif |
| |
| #ifdef PNG_READ_bKGD_SUPPORTED |
| void /* PRIVATE */ |
| png_handle_bKGD(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) |
| { |
| unsigned int truelen; |
| png_byte buf[6]; |
| png_color_16 background; |
| |
| png_debug(1, "in png_handle_bKGD"); |
| |
| if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) |
| png_chunk_error(png_ptr, "missing IHDR"); |
| |
| else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0 || |
| (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE && |
| (png_ptr->mode & PNG_HAVE_PLTE) == 0)) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "out of place"); |
| return; |
| } |
| |
| else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD) != 0) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "duplicate"); |
| return; |
| } |
| |
| if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) |
| truelen = 1; |
| |
| else if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0) |
| truelen = 6; |
| |
| else |
| truelen = 2; |
| |
| if (length != truelen) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "invalid"); |
| return; |
| } |
| |
| png_crc_read(png_ptr, buf, truelen); |
| |
| if (png_crc_finish(png_ptr, 0) != 0) |
| return; |
| |
| /* We convert the index value into RGB components so that we can allow |
| * arbitrary RGB values for background when we have transparency, and |
| * so it is easy to determine the RGB values of the background color |
| * from the info_ptr struct. |
| */ |
| if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) |
| { |
| background.index = buf[0]; |
| |
| if (info_ptr != NULL && info_ptr->num_palette != 0) |
| { |
| if (buf[0] >= info_ptr->num_palette) |
| { |
| png_chunk_benign_error(png_ptr, "invalid index"); |
| return; |
| } |
| |
| background.red = (png_uint_16)png_ptr->palette[buf[0]].red; |
| background.green = (png_uint_16)png_ptr->palette[buf[0]].green; |
| background.blue = (png_uint_16)png_ptr->palette[buf[0]].blue; |
| } |
| |
| else |
| background.red = background.green = background.blue = 0; |
| |
| background.gray = 0; |
| } |
| |
| else if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0) /* GRAY */ |
| { |
| if (png_ptr->bit_depth <= 8) |
| { |
| if (buf[0] != 0 || buf[1] >= (unsigned int)(1 << png_ptr->bit_depth)) |
| { |
| png_chunk_benign_error(png_ptr, "invalid gray level"); |
| return; |
| } |
| } |
| |
| background.index = 0; |
| background.red = |
| background.green = |
| background.blue = |
| background.gray = png_get_uint_16(buf); |
| } |
| |
| else |
| { |
| if (png_ptr->bit_depth <= 8) |
| { |
| if (buf[0] != 0 || buf[2] != 0 || buf[4] != 0) |
| { |
| png_chunk_benign_error(png_ptr, "invalid color"); |
| return; |
| } |
| } |
| |
| background.index = 0; |
| background.red = png_get_uint_16(buf); |
| background.green = png_get_uint_16(buf + 2); |
| background.blue = png_get_uint_16(buf + 4); |
| background.gray = 0; |
| } |
| |
| png_set_bKGD(png_ptr, info_ptr, &background); |
| } |
| #endif |
| |
| #ifdef PNG_READ_eXIf_SUPPORTED |
| void /* PRIVATE */ |
| png_handle_eXIf(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) |
| { |
| unsigned int i; |
| |
| png_debug(1, "in png_handle_eXIf"); |
| |
| if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) |
| png_chunk_error(png_ptr, "missing IHDR"); |
| |
| if (length < 2) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "too short"); |
| return; |
| } |
| |
| else if (info_ptr == NULL || (info_ptr->valid & PNG_INFO_eXIf) != 0) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "duplicate"); |
| return; |
| } |
| |
| info_ptr->free_me |= PNG_FREE_EXIF; |
| |
| info_ptr->eXIf_buf = png_voidcast(png_bytep, |
| png_malloc_warn(png_ptr, length)); |
| |
| if (info_ptr->eXIf_buf == NULL) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "out of memory"); |
| return; |
| } |
| |
| for (i = 0; i < length; i++) |
| { |
| png_byte buf[1]; |
| png_crc_read(png_ptr, buf, 1); |
| info_ptr->eXIf_buf[i] = buf[0]; |
| if (i == 1 && buf[0] != 'M' && buf[0] != 'I' |
| && info_ptr->eXIf_buf[0] != buf[0]) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "incorrect byte-order specifier"); |
| png_free(png_ptr, info_ptr->eXIf_buf); |
| info_ptr->eXIf_buf = NULL; |
| return; |
| } |
| } |
| |
| if (png_crc_finish(png_ptr, 0) != 0) |
| return; |
| |
| png_set_eXIf_1(png_ptr, info_ptr, length, info_ptr->eXIf_buf); |
| |
| png_free(png_ptr, info_ptr->eXIf_buf); |
| info_ptr->eXIf_buf = NULL; |
| } |
| #endif |
| |
| #ifdef PNG_READ_hIST_SUPPORTED |
| void /* PRIVATE */ |
| png_handle_hIST(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) |
| { |
| unsigned int num, i; |
| png_uint_16 readbuf[PNG_MAX_PALETTE_LENGTH]; |
| |
| png_debug(1, "in png_handle_hIST"); |
| |
| if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) |
| png_chunk_error(png_ptr, "missing IHDR"); |
| |
| else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0 || |
| (png_ptr->mode & PNG_HAVE_PLTE) == 0) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "out of place"); |
| return; |
| } |
| |
| else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST) != 0) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "duplicate"); |
| return; |
| } |
| |
| num = length / 2 ; |
| |
| if (num != (unsigned int) png_ptr->num_palette || |
| num > (unsigned int) PNG_MAX_PALETTE_LENGTH) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "invalid"); |
| return; |
| } |
| |
| for (i = 0; i < num; i++) |
| { |
| png_byte buf[2]; |
| |
| png_crc_read(png_ptr, buf, 2); |
| readbuf[i] = png_get_uint_16(buf); |
| } |
| |
| if (png_crc_finish(png_ptr, 0) != 0) |
| return; |
| |
| png_set_hIST(png_ptr, info_ptr, readbuf); |
| } |
| #endif |
| |
| #ifdef PNG_READ_pHYs_SUPPORTED |
| void /* PRIVATE */ |
| png_handle_pHYs(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) |
| { |
| png_byte buf[9]; |
| png_uint_32 res_x, res_y; |
| int unit_type; |
| |
| png_debug(1, "in png_handle_pHYs"); |
| |
| if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) |
| png_chunk_error(png_ptr, "missing IHDR"); |
| |
| else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "out of place"); |
| return; |
| } |
| |
| else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs) != 0) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "duplicate"); |
| return; |
| } |
| |
| if (length != 9) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "invalid"); |
| return; |
| } |
| |
| png_crc_read(png_ptr, buf, 9); |
| |
| if (png_crc_finish(png_ptr, 0) != 0) |
| return; |
| |
| res_x = png_get_uint_32(buf); |
| res_y = png_get_uint_32(buf + 4); |
| unit_type = buf[8]; |
| png_set_pHYs(png_ptr, info_ptr, res_x, res_y, unit_type); |
| } |
| #endif |
| |
| #ifdef PNG_READ_oFFs_SUPPORTED |
| void /* PRIVATE */ |
| png_handle_oFFs(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) |
| { |
| png_byte buf[9]; |
| png_int_32 offset_x, offset_y; |
| int unit_type; |
| |
| png_debug(1, "in png_handle_oFFs"); |
| |
| if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) |
| png_chunk_error(png_ptr, "missing IHDR"); |
| |
| else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "out of place"); |
| return; |
| } |
| |
| else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs) != 0) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "duplicate"); |
| return; |
| } |
| |
| if (length != 9) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "invalid"); |
| return; |
| } |
| |
| png_crc_read(png_ptr, buf, 9); |
| |
| if (png_crc_finish(png_ptr, 0) != 0) |
| return; |
| |
| offset_x = png_get_int_32(buf); |
| offset_y = png_get_int_32(buf + 4); |
| unit_type = buf[8]; |
| png_set_oFFs(png_ptr, info_ptr, offset_x, offset_y, unit_type); |
| } |
| #endif |
| |
| #ifdef PNG_READ_pCAL_SUPPORTED |
| /* Read the pCAL chunk (described in the PNG Extensions document) */ |
| void /* PRIVATE */ |
| png_handle_pCAL(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) |
| { |
| png_int_32 X0, X1; |
| png_byte type, nparams; |
| png_bytep buffer, buf, units, endptr; |
| png_charpp params; |
| int i; |
| |
| png_debug(1, "in png_handle_pCAL"); |
| |
| if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) |
| png_chunk_error(png_ptr, "missing IHDR"); |
| |
| else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "out of place"); |
| return; |
| } |
| |
| else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pCAL) != 0) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "duplicate"); |
| return; |
| } |
| |
| png_debug1(2, "Allocating and reading pCAL chunk data (%u bytes)", |
| length + 1); |
| |
| buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/); |
| |
| if (buffer == NULL) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "out of memory"); |
| return; |
| } |
| |
| png_crc_read(png_ptr, buffer, length); |
| |
| if (png_crc_finish(png_ptr, 0) != 0) |
| return; |
| |
| buffer[length] = 0; /* Null terminate the last string */ |
| |
| png_debug(3, "Finding end of pCAL purpose string"); |
| for (buf = buffer; *buf; buf++) |
| /* Empty loop */ ; |
| |
| endptr = buffer + length; |
| |
| /* We need to have at least 12 bytes after the purpose string |
| * in order to get the parameter information. |
| */ |
| if (endptr - buf <= 12) |
| { |
| png_chunk_benign_error(png_ptr, "invalid"); |
| return; |
| } |
| |
| png_debug(3, "Reading pCAL X0, X1, type, nparams, and units"); |
| X0 = png_get_int_32((png_bytep)buf+1); |
| X1 = png_get_int_32((png_bytep)buf+5); |
| type = buf[9]; |
| nparams = buf[10]; |
| units = buf + 11; |
| |
| png_debug(3, "Checking pCAL equation type and number of parameters"); |
| /* Check that we have the right number of parameters for known |
| * equation types. |
| */ |
| if ((type == PNG_EQUATION_LINEAR && nparams != 2) || |
| (type == PNG_EQUATION_BASE_E && nparams != 3) || |
| (type == PNG_EQUATION_ARBITRARY && nparams != 3) || |
| (type == PNG_EQUATION_HYPERBOLIC && nparams != 4)) |
| { |
| png_chunk_benign_error(png_ptr, "invalid parameter count"); |
| return; |
| } |
| |
| else if (type >= PNG_EQUATION_LAST) |
| { |
| png_chunk_benign_error(png_ptr, "unrecognized equation type"); |
| } |
| |
| for (buf = units; *buf; buf++) |
| /* Empty loop to move past the units string. */ ; |
| |
| png_debug(3, "Allocating pCAL parameters array"); |
| |
| params = png_voidcast(png_charpp, png_malloc_warn(png_ptr, |
| nparams * (sizeof (png_charp)))); |
| |
| if (params == NULL) |
| { |
| png_chunk_benign_error(png_ptr, "out of memory"); |
| return; |
| } |
| |
| /* Get pointers to the start of each parameter string. */ |
| for (i = 0; i < nparams; i++) |
| { |
| buf++; /* Skip the null string terminator from previous parameter. */ |
| |
| png_debug1(3, "Reading pCAL parameter %d", i); |
| |
| for (params[i] = (png_charp)buf; buf <= endptr && *buf != 0; buf++) |
| /* Empty loop to move past each parameter string */ ; |
| |
| /* Make sure we haven't run out of data yet */ |
| if (buf > endptr) |
| { |
| png_free(png_ptr, params); |
| png_chunk_benign_error(png_ptr, "invalid data"); |
| return; |
| } |
| } |
| |
| png_set_pCAL(png_ptr, info_ptr, (png_charp)buffer, X0, X1, type, nparams, |
| (png_charp)units, params); |
| |
| png_free(png_ptr, params); |
| } |
| #endif |
| |
| #ifdef PNG_READ_sCAL_SUPPORTED |
| /* Read the sCAL chunk */ |
| void /* PRIVATE */ |
| png_handle_sCAL(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) |
| { |
| png_bytep buffer; |
| size_t i; |
| int state; |
| |
| png_debug(1, "in png_handle_sCAL"); |
| |
| if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) |
| png_chunk_error(png_ptr, "missing IHDR"); |
| |
| else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "out of place"); |
| return; |
| } |
| |
| else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sCAL) != 0) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "duplicate"); |
| return; |
| } |
| |
| /* Need unit type, width, \0, height: minimum 4 bytes */ |
| else if (length < 4) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "invalid"); |
| return; |
| } |
| |
| png_debug1(2, "Allocating and reading sCAL chunk data (%u bytes)", |
| length + 1); |
| |
| buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/); |
| |
| if (buffer == NULL) |
| { |
| png_chunk_benign_error(png_ptr, "out of memory"); |
| png_crc_finish(png_ptr, length); |
| return; |
| } |
| |
| png_crc_read(png_ptr, buffer, length); |
| buffer[length] = 0; /* Null terminate the last string */ |
| |
| if (png_crc_finish(png_ptr, 0) != 0) |
| return; |
| |
| /* Validate the unit. */ |
| if (buffer[0] != 1 && buffer[0] != 2) |
| { |
| png_chunk_benign_error(png_ptr, "invalid unit"); |
| return; |
| } |
| |
| /* Validate the ASCII numbers, need two ASCII numbers separated by |
| * a '\0' and they need to fit exactly in the chunk data. |
| */ |
| i = 1; |
| state = 0; |
| |
| if (png_check_fp_number((png_const_charp)buffer, length, &state, &i) == 0 || |
| i >= length || buffer[i++] != 0) |
| png_chunk_benign_error(png_ptr, "bad width format"); |
| |
| else if (PNG_FP_IS_POSITIVE(state) == 0) |
| png_chunk_benign_error(png_ptr, "non-positive width"); |
| |
| else |
| { |
| size_t heighti = i; |
| |
| state = 0; |
| if (png_check_fp_number((png_const_charp)buffer, length, |
| &state, &i) == 0 || i != length) |
| png_chunk_benign_error(png_ptr, "bad height format"); |
| |
| else if (PNG_FP_IS_POSITIVE(state) == 0) |
| png_chunk_benign_error(png_ptr, "non-positive height"); |
| |
| else |
| /* This is the (only) success case. */ |
| png_set_sCAL_s(png_ptr, info_ptr, buffer[0], |
| (png_charp)buffer+1, (png_charp)buffer+heighti); |
| } |
| } |
| #endif |
| |
| #ifdef PNG_READ_tIME_SUPPORTED |
| void /* PRIVATE */ |
| png_handle_tIME(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) |
| { |
| png_byte buf[7]; |
| png_time mod_time; |
| |
| png_debug(1, "in png_handle_tIME"); |
| |
| if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) |
| png_chunk_error(png_ptr, "missing IHDR"); |
| |
| else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tIME) != 0) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "duplicate"); |
| return; |
| } |
| |
| if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) |
| png_ptr->mode |= PNG_AFTER_IDAT; |
| |
| if (length != 7) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "invalid"); |
| return; |
| } |
| |
| png_crc_read(png_ptr, buf, 7); |
| |
| if (png_crc_finish(png_ptr, 0) != 0) |
| return; |
| |
| mod_time.second = buf[6]; |
| mod_time.minute = buf[5]; |
| mod_time.hour = buf[4]; |
| mod_time.day = buf[3]; |
| mod_time.month = buf[2]; |
| mod_time.year = png_get_uint_16(buf); |
| |
| png_set_tIME(png_ptr, info_ptr, &mod_time); |
| } |
| #endif |
| |
| #ifdef PNG_READ_tEXt_SUPPORTED |
| /* Note: this does not properly handle chunks that are > 64K under DOS */ |
| void /* PRIVATE */ |
| png_handle_tEXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) |
| { |
| png_text text_info; |
| png_bytep buffer; |
| png_charp key; |
| png_charp text; |
| png_uint_32 skip = 0; |
| |
| png_debug(1, "in png_handle_tEXt"); |
| |
| #ifdef PNG_USER_LIMITS_SUPPORTED |
| if (png_ptr->user_chunk_cache_max != 0) |
| { |
| if (png_ptr->user_chunk_cache_max == 1) |
| { |
| png_crc_finish(png_ptr, length); |
| return; |
| } |
| |
| if (--png_ptr->user_chunk_cache_max == 1) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "no space in chunk cache"); |
| return; |
| } |
| } |
| #endif |
| |
| if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) |
| png_chunk_error(png_ptr, "missing IHDR"); |
| |
| if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) |
| png_ptr->mode |= PNG_AFTER_IDAT; |
| |
| #ifdef PNG_MAX_MALLOC_64K |
| if (length > 65535U) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "too large to fit in memory"); |
| return; |
| } |
| #endif |
| |
| buffer = png_read_buffer(png_ptr, length+1, 1/*warn*/); |
| |
| if (buffer == NULL) |
| { |
| png_chunk_benign_error(png_ptr, "out of memory"); |
| return; |
| } |
| |
| png_crc_read(png_ptr, buffer, length); |
| |
| if (png_crc_finish(png_ptr, skip) != 0) |
| return; |
| |
| key = (png_charp)buffer; |
| key[length] = 0; |
| |
| for (text = key; *text; text++) |
| /* Empty loop to find end of key */ ; |
| |
| if (text != key + length) |
| text++; |
| |
| text_info.compression = PNG_TEXT_COMPRESSION_NONE; |
| text_info.key = key; |
| text_info.lang = NULL; |
| text_info.lang_key = NULL; |
| text_info.itxt_length = 0; |
| text_info.text = text; |
| text_info.text_length = strlen(text); |
| |
| if (png_set_text_2(png_ptr, info_ptr, &text_info, 1) != 0) |
| png_warning(png_ptr, "Insufficient memory to process text chunk"); |
| } |
| #endif |
| |
| #ifdef PNG_READ_zTXt_SUPPORTED |
| /* Note: this does not correctly handle chunks that are > 64K under DOS */ |
| void /* PRIVATE */ |
| png_handle_zTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) |
| { |
| png_const_charp errmsg = NULL; |
| png_bytep buffer; |
| png_uint_32 keyword_length; |
| |
| png_debug(1, "in png_handle_zTXt"); |
| |
| #ifdef PNG_USER_LIMITS_SUPPORTED |
| if (png_ptr->user_chunk_cache_max != 0) |
| { |
| if (png_ptr->user_chunk_cache_max == 1) |
| { |
| png_crc_finish(png_ptr, length); |
| return; |
| } |
| |
| if (--png_ptr->user_chunk_cache_max == 1) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "no space in chunk cache"); |
| return; |
| } |
| } |
| #endif |
| |
| if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) |
| png_chunk_error(png_ptr, "missing IHDR"); |
| |
| if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) |
| png_ptr->mode |= PNG_AFTER_IDAT; |
| |
| /* Note, "length" is sufficient here; we won't be adding |
| * a null terminator later. |
| */ |
| buffer = png_read_buffer(png_ptr, length, 2/*silent*/); |
| |
| if (buffer == NULL) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "out of memory"); |
| return; |
| } |
| |
| png_crc_read(png_ptr, buffer, length); |
| |
| if (png_crc_finish(png_ptr, 0) != 0) |
| return; |
| |
| /* TODO: also check that the keyword contents match the spec! */ |
| for (keyword_length = 0; |
| keyword_length < length && buffer[keyword_length] != 0; |
| ++keyword_length) |
| /* Empty loop to find end of name */ ; |
| |
| if (keyword_length > 79 || keyword_length < 1) |
| errmsg = "bad keyword"; |
| |
| /* zTXt must have some LZ data after the keyword, although it may expand to |
| * zero bytes; we need a '\0' at the end of the keyword, the compression type |
| * then the LZ data: |
| */ |
| else if (keyword_length + 3 > length) |
| errmsg = "truncated"; |
| |
| else if (buffer[keyword_length+1] != PNG_COMPRESSION_TYPE_BASE) |
| errmsg = "unknown compression type"; |
| |
| else |
| { |
| png_alloc_size_t uncompressed_length = PNG_SIZE_MAX; |
| |
| /* TODO: at present png_decompress_chunk imposes a single application |
| * level memory limit, this should be split to different values for iCCP |
| * and text chunks. |
| */ |
| if (png_decompress_chunk(png_ptr, length, keyword_length+2, |
| &uncompressed_length, 1/*terminate*/) == Z_STREAM_END) |
| { |
| png_text text; |
| |
| if (png_ptr->read_buffer == NULL) |
| errmsg="Read failure in png_handle_zTXt"; |
| else |
| { |
| /* It worked; png_ptr->read_buffer now looks like a tEXt chunk |
| * except for the extra compression type byte and the fact that |
| * it isn't necessarily '\0' terminated. |
| */ |
| buffer = png_ptr->read_buffer; |
| buffer[uncompressed_length+(keyword_length+2)] = 0; |
| |
| text.compression = PNG_TEXT_COMPRESSION_zTXt; |
| text.key = (png_charp)buffer; |
| text.text = (png_charp)(buffer + keyword_length+2); |
| text.text_length = uncompressed_length; |
| text.itxt_length = 0; |
| text.lang = NULL; |
| text.lang_key = NULL; |
| |
| if (png_set_text_2(png_ptr, info_ptr, &text, 1) != 0) |
| errmsg = "insufficient memory"; |
| } |
| } |
| |
| else |
| errmsg = png_ptr->zstream.msg; |
| } |
| |
| if (errmsg != NULL) |
| png_chunk_benign_error(png_ptr, errmsg); |
| } |
| #endif |
| |
| #ifdef PNG_READ_iTXt_SUPPORTED |
| /* Note: this does not correctly handle chunks that are > 64K under DOS */ |
| void /* PRIVATE */ |
| png_handle_iTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) |
| { |
| png_const_charp errmsg = NULL; |
| png_bytep buffer; |
| png_uint_32 prefix_length; |
| |
| png_debug(1, "in png_handle_iTXt"); |
| |
| #ifdef PNG_USER_LIMITS_SUPPORTED |
| if (png_ptr->user_chunk_cache_max != 0) |
| { |
| if (png_ptr->user_chunk_cache_max == 1) |
| { |
| png_crc_finish(png_ptr, length); |
| return; |
| } |
| |
| if (--png_ptr->user_chunk_cache_max == 1) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "no space in chunk cache"); |
| return; |
| } |
| } |
| #endif |
| |
| if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) |
| png_chunk_error(png_ptr, "missing IHDR"); |
| |
| if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) |
| png_ptr->mode |= PNG_AFTER_IDAT; |
| |
| buffer = png_read_buffer(png_ptr, length+1, 1/*warn*/); |
| |
| if (buffer == NULL) |
| { |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "out of memory"); |
| return; |
| } |
| |
| png_crc_read(png_ptr, buffer, length); |
| |
| if (png_crc_finish(png_ptr, 0) != 0) |
| return; |
| |
| /* First the keyword. */ |
| for (prefix_length=0; |
| prefix_length < length && buffer[prefix_length] != 0; |
| ++prefix_length) |
| /* Empty loop */ ; |
| |
| /* Perform a basic check on the keyword length here. */ |
| if (prefix_length > 79 || prefix_length < 1) |
| errmsg = "bad keyword"; |
| |
| /* Expect keyword, compression flag, compression type, language, translated |
| * keyword (both may be empty but are 0 terminated) then the text, which may |
| * be empty. |
| */ |
| else if (prefix_length + 5 > length) |
| errmsg = "truncated"; |
| |
| else if (buffer[prefix_length+1] == 0 || |
| (buffer[prefix_length+1] == 1 && |
| buffer[prefix_length+2] == PNG_COMPRESSION_TYPE_BASE)) |
| { |
| int compressed = buffer[prefix_length+1] != 0; |
| png_uint_32 language_offset, translated_keyword_offset; |
| png_alloc_size_t uncompressed_length = 0; |
| |
| /* Now the language tag */ |
| prefix_length += 3; |
| language_offset = prefix_length; |
| |
| for (; prefix_length < length && buffer[prefix_length] != 0; |
| ++prefix_length) |
| /* Empty loop */ ; |
| |
| /* WARNING: the length may be invalid here, this is checked below. */ |
| translated_keyword_offset = ++prefix_length; |
| |
| for (; prefix_length < length && buffer[prefix_length] != 0; |
| ++prefix_length) |
| /* Empty loop */ ; |
| |
| /* prefix_length should now be at the trailing '\0' of the translated |
| * keyword, but it may already be over the end. None of this arithmetic |
| * can overflow because chunks are at most 2^31 bytes long, but on 16-bit |
| * systems the available allocation may overflow. |
| */ |
| ++prefix_length; |
| |
| if (compressed == 0 && prefix_length <= length) |
| uncompressed_length = length - prefix_length; |
| |
| else if (compressed != 0 && prefix_length < length) |
| { |
| uncompressed_length = PNG_SIZE_MAX; |
| |
| /* TODO: at present png_decompress_chunk imposes a single application |
| * level memory limit, this should be split to different values for |
| * iCCP and text chunks. |
| */ |
| if (png_decompress_chunk(png_ptr, length, prefix_length, |
| &uncompressed_length, 1/*terminate*/) == Z_STREAM_END) |
| buffer = png_ptr->read_buffer; |
| |
| else |
| errmsg = png_ptr->zstream.msg; |
| } |
| |
| else |
| errmsg = "truncated"; |
| |
| if (errmsg == NULL) |
| { |
| png_text text; |
| |
| buffer[uncompressed_length+prefix_length] = 0; |
| |
| if (compressed == 0) |
| text.compression = PNG_ITXT_COMPRESSION_NONE; |
| |
| else |
| text.compression = PNG_ITXT_COMPRESSION_zTXt; |
| |
| text.key = (png_charp)buffer; |
| text.lang = (png_charp)buffer + language_offset; |
| text.lang_key = (png_charp)buffer + translated_keyword_offset; |
| text.text = (png_charp)buffer + prefix_length; |
| text.text_length = 0; |
| text.itxt_length = uncompressed_length; |
| |
| if (png_set_text_2(png_ptr, info_ptr, &text, 1) != 0) |
| errmsg = "insufficient memory"; |
| } |
| } |
| |
| else |
| errmsg = "bad compression info"; |
| |
| if (errmsg != NULL) |
| png_chunk_benign_error(png_ptr, errmsg); |
| } |
| #endif |
| |
| #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED |
| /* Utility function for png_handle_unknown; set up png_ptr::unknown_chunk */ |
| static int |
| png_cache_unknown_chunk(png_structrp png_ptr, png_uint_32 length) |
| { |
| png_alloc_size_t limit = PNG_SIZE_MAX; |
| |
| if (png_ptr->unknown_chunk.data != NULL) |
| { |
| png_free(png_ptr, png_ptr->unknown_chunk.data); |
| png_ptr->unknown_chunk.data = NULL; |
| } |
| |
| # ifdef PNG_SET_USER_LIMITS_SUPPORTED |
| if (png_ptr->user_chunk_malloc_max > 0 && |
| png_ptr->user_chunk_malloc_max < limit) |
| limit = png_ptr->user_chunk_malloc_max; |
| |
| # elif PNG_USER_CHUNK_MALLOC_MAX > 0 |
| if (PNG_USER_CHUNK_MALLOC_MAX < limit) |
| limit = PNG_USER_CHUNK_MALLOC_MAX; |
| # endif |
| |
| if (length <= limit) |
| { |
| PNG_CSTRING_FROM_CHUNK(png_ptr->unknown_chunk.name, png_ptr->chunk_name); |
| /* The following is safe because of the PNG_SIZE_MAX init above */ |
| png_ptr->unknown_chunk.size = (size_t)length/*SAFE*/; |
| /* 'mode' is a flag array, only the bottom four bits matter here */ |
| png_ptr->unknown_chunk.location = (png_byte)png_ptr->mode/*SAFE*/; |
| |
| if (length == 0) |
| png_ptr->unknown_chunk.data = NULL; |
| |
| else |
| { |
| /* Do a 'warn' here - it is handled below. */ |
| png_ptr->unknown_chunk.data = png_voidcast(png_bytep, |
| png_malloc_warn(png_ptr, length)); |
| } |
| } |
| |
| if (png_ptr->unknown_chunk.data == NULL && length > 0) |
| { |
| /* This is benign because we clean up correctly */ |
| png_crc_finish(png_ptr, length); |
| png_chunk_benign_error(png_ptr, "unknown chunk exceeds memory limits"); |
| return 0; |
| } |
| |
| else |
| { |
| if (length > 0) |
| png_crc_read(png_ptr, png_ptr->unknown_chunk.data, length); |
| png_crc_finish(png_ptr, 0); |
| return 1; |
| } |
| } |
| #endif /* READ_UNKNOWN_CHUNKS */ |
| |
| /* Handle an unknown, or known but disabled, chunk */ |
| void /* PRIVATE */ |
| png_handle_unknown(png_structrp png_ptr, png_inforp info_ptr, |
| png_uint_32 length, int keep) |
| { |
| int handled = 0; /* the chunk was handled */ |
| |
| png_debug(1, "in png_handle_unknown"); |
| |
| #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED |
| /* NOTE: this code is based on the code in libpng-1.4.12 except for fixing |
| * the bug which meant that setting a non-default behavior for a specific |
| * chunk would be ignored (the default was always used unless a user |
| * callback was installed). |
| * |
| * 'keep' is the value from the png_chunk_unknown_handling, the setting for |
| * this specific chunk_name, if PNG_HANDLE_AS_UNKNOWN_SUPPORTED, if not it |
| * will always be PNG_HANDLE_CHUNK_AS_DEFAULT and it needs to be set here. |
| * This is just an optimization to avoid multiple calls to the lookup |
| * function. |
| */ |
| # ifndef PNG_HANDLE_AS_UNKNOWN_SUPPORTED |
| # ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED |
| keep = png_chunk_unknown_handling(png_ptr, png_ptr->chunk_name); |
| # endif |
| # endif |
| |
| /* One of the following methods will read the chunk or skip it (at least one |
| * of these is always defined because this is the only way to switch on |
| * PNG_READ_UNKNOWN_CHUNKS_SUPPORTED) |
| */ |
| # ifdef PNG_READ_USER_CHUNKS_SUPPORTED |
| /* The user callback takes precedence over the chunk keep value, but the |
| * keep value is still required to validate a save of a critical chunk. |
| */ |
| if (png_ptr->read_user_chunk_fn != NULL) |
| { |
| if (png_cache_unknown_chunk(png_ptr, length) != 0) |
| { |
| /* Callback to user unknown chunk handler */ |
| int ret = (*(png_ptr->read_user_chunk_fn))(png_ptr, |
| &png_ptr->unknown_chunk); |
| |
| /* ret is: |
| * negative: An error occurred; png_chunk_error will be called. |
| * zero: The chunk was not handled, the chunk will be discarded |
| * unless png_set_keep_unknown_chunks has been used to set |
| * a 'keep' behavior for this particular chunk, in which |
| * case that will be used. A critical chunk will cause an |
| * error at this point unless it is to be saved. |
| * positive: The chunk was handled, libpng will ignore/discard it. |
| */ |
| if (ret < 0) |
| png_chunk_error(png_ptr, "error in user chunk"); |
| |
| else if (ret == 0) |
| { |
| /* If the keep value is 'default' or 'never' override it, but |
| * still error out on critical chunks unless the keep value is |
| * 'always' While this is weird it is the behavior in 1.4.12. |
| * A possible improvement would be to obey the value set for the |
| * chunk, but this would be an API change that would probably |
| * damage some applications. |
| * |
| * The png_app_warning below catches the case that matters, where |
| * the application has not set specific save or ignore for this |
| * chunk or global save or ignore. |
| */ |
| if (keep < PNG_HANDLE_CHUNK_IF_SAFE) |
| { |
| # ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED |
| if (png_ptr->unknown_default < PNG_HANDLE_CHUNK_IF_SAFE) |
| { |
| png_chunk_warning(png_ptr, "Saving unknown chunk:"); |
| png_app_warning(png_ptr, |
| "forcing save of an unhandled chunk;" |
| " please call png_set_keep_unknown_chunks"); |
| /* with keep = PNG_HANDLE_CHUNK_IF_SAFE */ |
| } |
| # endif |
| keep = PNG_HANDLE_CHUNK_IF_SAFE; |
| } |
| } |
| |
| else /* chunk was handled */ |
| { |
| handled = 1; |
| /* Critical chunks can be safely discarded at this point. */ |
| keep = PNG_HANDLE_CHUNK_NEVER; |
| } |
| } |
| |
| else |
| keep = PNG_HANDLE_CHUNK_NEVER; /* insufficient memory */ |
| } |
| |
| else |
| /* Use the SAVE_UNKNOWN_CHUNKS code or skip the chunk */ |
| # endif /* READ_USER_CHUNKS */ |
| |
| # ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED |
| { |
| /* keep is currently just the per-chunk setting, if there was no |
| * setting change it to the global default now (not that this may |
| * still be AS_DEFAULT) then obtain the cache of the chunk if required, |
| * if not simply skip the chunk. |
| */ |
| if (keep == PNG_HANDLE_CHUNK_AS_DEFAULT) |
| keep = png_ptr->unknown_default; |
| |
| if (keep == PNG_HANDLE_CHUNK_ALWAYS || |
| (keep == PNG_HANDLE_CHUNK_IF_SAFE && |
| PNG_CHUNK_ANCILLARY(png_ptr->chunk_name))) |
| { |
| if (png_cache_unknown_chunk(png_ptr, length) == 0) |
| keep = PNG_HANDLE_CHUNK_NEVER; |
| } |
| |
| else |
| png_crc_finish(png_ptr, length); |
| } |
| # else |
| # ifndef PNG_READ_USER_CHUNKS_SUPPORTED |
| # error no method to support READ_UNKNOWN_CHUNKS |
| # endif |
| |
| { |
| /* If here there is no read callback pointer set and no support is |
| * compiled in to just save the unknown chunks, so simply skip this |
| * chunk. If 'keep' is something other than AS_DEFAULT or NEVER then |
| * the app has erroneously asked for unknown chunk saving when there |
| * is no support. |
| */ |
| if (keep > PNG_HANDLE_CHUNK_NEVER) |
| png_app_error(png_ptr, "no unknown chunk support available"); |
| |
| png_crc_finish(png_ptr, length); |
| } |
| # endif |
| |
| # ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED |
| /* Now store the chunk in the chunk list if appropriate, and if the limits |
| * permit it. |
| */ |
| if (keep == PNG_HANDLE_CHUNK_ALWAYS || |
| (keep == PNG_HANDLE_CHUNK_IF_SAFE && |
| PNG_CHUNK_ANCILLARY(png_ptr->chunk_name))) |
| { |
| # ifdef PNG_USER_LIMITS_SUPPORTED |
| switch (png_ptr->user_chunk_cache_max) |
| { |
| case 2: |
| png_ptr->user_chunk_cache_max = 1; |
| png_chunk_benign_error(png_ptr, "no space in chunk cache"); |
| /* FALLTHROUGH */ |
| case 1: |
| /* NOTE: prior to 1.6.0 this case resulted in an unknown critical |
| * chunk being skipped, now there will be a hard error below. |
| */ |
| break; |
| |
| default: /* not at limit */ |
| --(png_ptr->user_chunk_cache_max); |
| /* FALLTHROUGH */ |
| case 0: /* no limit */ |
| # endif /* USER_LIMITS */ |
| /* Here when the limit isn't reached or when limits are compiled |
| * out; store the chunk. |
| */ |
| png_set_unknown_chunks(png_ptr, info_ptr, |
| &png_ptr->unknown_chunk, 1); |
| handled = 1; |
| # ifdef PNG_USER_LIMITS_SUPPORTED |
| break; |
| } |
| # endif |
| } |
| # else /* no store support: the chunk must be handled by the user callback */ |
| PNG_UNUSED(info_ptr) |
| # endif |
| |
| /* Regardless of the error handling below the cached data (if any) can be |
| * freed now. Notice that the data is not freed if there is a png_error, but |
| * it will be freed by destroy_read_struct. |
| */ |
| if (png_ptr->unknown_chunk.data != NULL) |
| png_free(png_ptr, png_ptr->unknown_chunk.data); |
| png_ptr->unknown_chunk.data = NULL; |
| |
| #else /* !PNG_READ_UNKNOWN_CHUNKS_SUPPORTED */ |
| /* There is no support to read an unknown chunk, so just skip it. */ |
| png_crc_finish(png_ptr, length); |
| PNG_UNUSED(info_ptr) |
| PNG_UNUSED(keep) |
| #endif /* !READ_UNKNOWN_CHUNKS */ |
| |
| /* Check for unhandled critical chunks */ |
| if (handled == 0 && PNG_CHUNK_CRITICAL(png_ptr->chunk_name)) |
| png_chunk_error(png_ptr, "unhandled critical chunk"); |
| } |
| |
| /* This function is called to verify that a chunk name is valid. |
| * This function can't have the "critical chunk check" incorporated |
| * into it, since in the future we will need to be able to call user |
| * functions to handle unknown critical chunks after we check that |
| * the chunk name itself is valid. |
| */ |
| |
| /* Bit hacking: the test for an invalid byte in the 4 byte chunk name is: |
| * |
| * ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97)) |
| */ |
| |
| void /* PRIVATE */ |
| png_check_chunk_name(png_const_structrp png_ptr, png_uint_32 chunk_name) |
| { |
| int i; |
| png_uint_32 cn=chunk_name; |
| |
| png_debug(1, "in png_check_chunk_name"); |
| |
| for (i=1; i<=4; ++i) |
| { |
| int c = cn & 0xff; |
| |
| if (c < 65 || c > 122 || (c > 90 && c < 97)) |
| png_chunk_error(png_ptr, "invalid chunk type"); |
| |
| cn >>= 8; |
| } |
| } |
| |
| void /* PRIVATE */ |
| png_check_chunk_length(png_const_structrp png_ptr, png_uint_32 length) |
| { |
| png_alloc_size_t limit = PNG_UINT_31_MAX; |
| |
| # ifdef PNG_SET_USER_LIMITS_SUPPORTED |
| if (png_ptr->user_chunk_malloc_max > 0 && |
| png_ptr->user_chunk_malloc_max < limit) |
| limit = png_ptr->user_chunk_malloc_max; |
| # elif PNG_USER_CHUNK_MALLOC_MAX > 0 |
| if (PNG_USER_CHUNK_MALLOC_MAX < limit) |
| limit = PNG_USER_CHUNK_MALLOC_MAX; |
| # endif |
| if (png_ptr->chunk_name == png_IDAT) |
| { |
| png_alloc_size_t idat_limit = PNG_UINT_31_MAX; |
| size_t row_factor = |
| (size_t)png_ptr->width |
| * (size_t)png_ptr->channels |
| * (png_ptr->bit_depth > 8? 2: 1) |
| + 1 |
| + (png_ptr->interlaced? 6: 0); |
| if (png_ptr->height > PNG_UINT_32_MAX/row_factor) |
| idat_limit = PNG_UINT_31_MAX; |
| else |
| idat_limit = png_ptr->height * row_factor; |
| row_factor = row_factor > 32566? 32566 : row_factor; |
| idat_limit += 6 + 5*( |