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Diffstat (limited to 'third_party/libpng16/pngrutil.c')
| -rw-r--r-- | third_party/libpng16/pngrutil.c | 4529 |
1 files changed, 4529 insertions, 0 deletions
diff --git a/third_party/libpng16/pngrutil.c b/third_party/libpng16/pngrutil.c new file mode 100644 index 0000000000..6189251352 --- /dev/null +++ b/third_party/libpng16/pngrutil.c @@ -0,0 +1,4529 @@ + +/* pngrutil.c - utilities to read a PNG file + * + * Last changed in libpng 1.6.20 [December 3, 2015] + * Copyright (c) 1998-2015 Glenn Randers-Pehrson + * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) + * (Version 0.88 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 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 accomodate 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) +{ + png_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); + +#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) + { + 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 PNG_ZLIB_VERNUM >= 0x1240 + +# if defined(PNG_SET_OPTION_SUPPORTED) && defined(PNG_MAXIMUM_INFLATE_WINDOW) + int window_bits; + + if (((png_ptr->options >> PNG_MAXIMUM_INFLATE_WINDOW) & 3) == + PNG_OPTION_ON) + { + window_bits = 15; + png_ptr->zstream_start = 0; /* fixed window size */ + } + + else + { + window_bits = 0; + png_ptr->zstream_start = 1; + } +# else +# define window_bits 0 +# endif +#endif + + /* 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 PNG_ZLIB_VERNUM < 0x1240 + ret = inflateReset(&png_ptr->zstream); +#else + ret = inflateReset2(&png_ptr->zstream, window_bits); +#endif + } + + else + { +#if PNG_ZLIB_VERNUM < 0x1240 + ret = inflateInit(&png_ptr->zstream); +#else + ret = inflateInit2(&png_ptr->zstream, window_bits); +#endif + + if (ret == Z_OK) + png_ptr->flags |= PNG_FLAG_ZSTREAM_INITIALIZED; + } + + 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 PNG_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 +/* 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) + { + 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); + + if (ret == Z_STREAM_END) + 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_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 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, (int) length - 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 minimum 'deflate' stream is assumed to be just the 2 byte header and + * 4 byte checksum. The keyword must be at least one character and there is + * a terminator (0) byte and the compression method. + */ + if (length < 9) + { + 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; + + 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]; + 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. + */ + const 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 these stuff will overflow. + */ + const 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; + +# ifdef PNG_sRGB_SUPPORTED + /* 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; + } + } + + else if (size > 0) + errmsg = "truncated"; + +#ifndef __COVERITY__ + else + errmsg = png_ptr->zstream.msg; +#endif + } + + /* 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; + png_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 % entry_size) != 0) + { + png_warning(png_ptr, "sPLT chunk has bad length"); + return; + } + + dl = (png_int_32)(data_length / 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 / entry_size); + + new_palette.entries = (png_sPLT_entryp)png_malloc_warn( + png_ptr, 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 */ + { + background.index = 0; + background.red = + background.green = + background.blue = + background.gray = png_get_uint_16(buf); + } + + else + { + 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_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; + png_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 + { + png_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; + + 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; + + /* 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 = (png_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"); + /* FALL THROUGH */ + 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); + /* FALL THROUGH */ + 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_structrp png_ptr, png_uint_32 chunk_name) +{ + int i; + + png_debug(1, "in png_check_chunk_name"); + + for (i=1; i<=4; ++i) + { + int c = chunk_name & 0xff; + + if (c < 65 || c > 122 || (c > 90 && c < 97)) + png_chunk_error(png_ptr, "invalid chunk type"); + + chunk_name >>= 8; + } +} + +/* Combines the row recently read in with the existing pixels in the row. This + * routine takes care of alpha and transparency if requested. This routine also + * handles the two methods of progressive display of interlaced images, + * depending on the 'display' value; if 'display' is true then the whole row + * (dp) is filled from the start by replicating the available pixels. If + * 'display' is false only those pixels present in the pass are filled in. + */ +void /* PRIVATE */ +png_combine_row(png_const_structrp png_ptr, png_bytep dp, int display) +{ + unsigned int pixel_depth = png_ptr->transformed_pixel_depth; + png_const_bytep sp = png_ptr->row_buf + 1; + png_alloc_size_t row_width = png_ptr->width; + unsigned int pass = png_ptr->pass; + png_bytep end_ptr = 0; + png_byte end_byte = 0; + unsigned int end_mask; + + png_debug(1, "in png_combine_row"); + + /* Added in 1.5.6: it should not be possible to enter this routine until at + * least one row has been read from the PNG data and transformed. + */ + if (pixel_depth == 0) + png_error(png_ptr, "internal row logic error"); + + /* Added in 1.5.4: the pixel depth should match the information returned by + * any call to png_read_update_info at this point. Do not continue if we got + * this wrong. + */ + if (png_ptr->info_rowbytes != 0 && png_ptr->info_rowbytes != + PNG_ROWBYTES(pixel_depth, row_width)) + png_error(png_ptr, "internal row size calculation error"); + + /* Don't expect this to ever happen: */ + if (row_width == 0) + png_error(png_ptr, "internal row width error"); + + /* Preserve the last byte in cases where only part of it will be overwritten, + * the multiply below may overflow, we don't care because ANSI-C guarantees + * we get the low bits. + */ + end_mask = (pixel_depth * row_width) & 7; + if (end_mask != 0) + { + /* end_ptr == NULL is a flag to say do nothing */ + end_ptr = dp + PNG_ROWBYTES(pixel_depth, row_width) - 1; + end_byte = *end_ptr; +# ifdef PNG_READ_PACKSWAP_SUPPORTED + if ((png_ptr->transformations & PNG_PACKSWAP) != 0) + /* little-endian byte */ + end_mask = 0xff << end_mask; + + else /* big-endian byte */ +# endif + end_mask = 0xff >> end_mask; + /* end_mask is now the bits to *keep* from the destination row */ + } + + /* For non-interlaced images this reduces to a memcpy(). A memcpy() + * will also happen if interlacing isn't supported or if the application + * does not call png_set_interlace_handling(). In the latter cases the + * caller just gets a sequence of the unexpanded rows from each interlace + * pass. + */ +#ifdef PNG_READ_INTERLACING_SUPPORTED + if (png_ptr->interlaced != 0 && + (png_ptr->transformations & PNG_INTERLACE) != 0 && + pass < 6 && (display == 0 || + /* The following copies everything for 'display' on passes 0, 2 and 4. */ + (display == 1 && (pass & 1) != 0))) + { + /* Narrow images may have no bits in a pass; the caller should handle + * this, but this test is cheap: + */ + if (row_width <= PNG_PASS_START_COL(pass)) + return; + + if (pixel_depth < 8) + { + /* For pixel depths up to 4 bpp the 8-pixel mask can be expanded to fit + * into 32 bits, then a single loop over the bytes using the four byte + * values in the 32-bit mask can be used. For the 'display' option the + * expanded mask may also not require any masking within a byte. To + * make this work the PACKSWAP option must be taken into account - it + * simply requires the pixels to be reversed in each byte. + * + * The 'regular' case requires a mask for each of the first 6 passes, + * the 'display' case does a copy for the even passes in the range + * 0..6. This has already been handled in the test above. + * + * The masks are arranged as four bytes with the first byte to use in + * the lowest bits (little-endian) regardless of the order (PACKSWAP or + * not) of the pixels in each byte. + * + * NOTE: the whole of this logic depends on the caller of this function + * only calling it on rows appropriate to the pass. This function only + * understands the 'x' logic; the 'y' logic is handled by the caller. + * + * The following defines allow generation of compile time constant bit + * masks for each pixel depth and each possibility of swapped or not + * swapped bytes. Pass 'p' is in the range 0..6; 'x', a pixel index, + * is in the range 0..7; and the result is 1 if the pixel is to be + * copied in the pass, 0 if not. 'S' is for the sparkle method, 'B' + * for the block method. + * + * With some compilers a compile time expression of the general form: + * + * (shift >= 32) ? (a >> (shift-32)) : (b >> shift) + * + * Produces warnings with values of 'shift' in the range 33 to 63 + * because the right hand side of the ?: expression is evaluated by + * the compiler even though it isn't used. Microsoft Visual C (various + * versions) and the Intel C compiler are known to do this. To avoid + * this the following macros are used in 1.5.6. This is a temporary + * solution to avoid destabilizing the code during the release process. + */ +# if PNG_USE_COMPILE_TIME_MASKS +# define PNG_LSR(x,s) ((x)>>((s) & 0x1f)) +# define PNG_LSL(x,s) ((x)<<((s) & 0x1f)) +# else +# define PNG_LSR(x,s) ((x)>>(s)) +# define PNG_LSL(x,s) ((x)<<(s)) +# endif +# define S_COPY(p,x) (((p)<4 ? PNG_LSR(0x80088822,(3-(p))*8+(7-(x))) :\ + PNG_LSR(0xaa55ff00,(7-(p))*8+(7-(x)))) & 1) +# define B_COPY(p,x) (((p)<4 ? PNG_LSR(0xff0fff33,(3-(p))*8+(7-(x))) :\ + PNG_LSR(0xff55ff00,(7-(p))*8+(7-(x)))) & 1) + + /* Return a mask for pass 'p' pixel 'x' at depth 'd'. The mask is + * little endian - the first pixel is at bit 0 - however the extra + * parameter 's' can be set to cause the mask position to be swapped + * within each byte, to match the PNG format. This is done by XOR of + * the shift with 7, 6 or 4 for bit depths 1, 2 and 4. + */ +# define PIXEL_MASK(p,x,d,s) \ + (PNG_LSL(((PNG_LSL(1U,(d)))-1),(((x)*(d))^((s)?8-(d):0)))) + + /* Hence generate the appropriate 'block' or 'sparkle' pixel copy mask. + */ +# define S_MASKx(p,x,d,s) (S_COPY(p,x)?PIXEL_MASK(p,x,d,s):0) +# define B_MASKx(p,x,d,s) (B_COPY(p,x)?PIXEL_MASK(p,x,d,s):0) + + /* Combine 8 of these to get the full mask. For the 1-bpp and 2-bpp + * cases the result needs replicating, for the 4-bpp case the above + * generates a full 32 bits. + */ +# define MASK_EXPAND(m,d) ((m)*((d)==1?0x01010101:((d)==2?0x00010001:1))) + +# define S_MASK(p,d,s) MASK_EXPAND(S_MASKx(p,0,d,s) + S_MASKx(p,1,d,s) +\ + S_MASKx(p,2,d,s) + S_MASKx(p,3,d,s) + S_MASKx(p,4,d,s) +\ + S_MASKx(p,5,d,s) + S_MASKx(p,6,d,s) + S_MASKx(p,7,d,s), d) + +# define B_MASK(p,d,s) MASK_EXPAND(B_MASKx(p,0,d,s) + B_MASKx(p,1,d,s) +\ + B_MASKx(p,2,d,s) + B_MASKx(p,3,d,s) + B_MASKx(p,4,d,s) +\ + B_MASKx(p,5,d,s) + B_MASKx(p,6,d,s) + B_MASKx(p,7,d,s), d) + +#if PNG_USE_COMPILE_TIME_MASKS + /* Utility macros to construct all the masks for a depth/swap + * combination. The 's' parameter says whether the format is PNG + * (big endian bytes) or not. Only the three odd-numbered passes are + * required for the display/block algorithm. + */ +# define S_MASKS(d,s) { S_MASK(0,d,s), S_MASK(1,d,s), S_MASK(2,d,s),\ + S_MASK(3,d,s), S_MASK(4,d,s), S_MASK(5,d,s) } + +# define B_MASKS(d,s) { B_MASK(1,d,s), B_MASK(3,d,s), B_MASK(5,d,s) } + +# define DEPTH_INDEX(d) ((d)==1?0:((d)==2?1:2)) + + /* Hence the pre-compiled masks indexed by PACKSWAP (or not), depth and + * then pass: + */ + static PNG_CONST png_uint_32 row_mask[2/*PACKSWAP*/][3/*depth*/][6] = + { + /* Little-endian byte masks for PACKSWAP */ + { S_MASKS(1,0), S_MASKS(2,0), S_MASKS(4,0) }, + /* Normal (big-endian byte) masks - PNG format */ + { S_MASKS(1,1), S_MASKS(2,1), S_MASKS(4,1) } + }; + + /* display_mask has only three entries for the odd passes, so index by + * pass>>1. + */ + static PNG_CONST png_uint_32 display_mask[2][3][3] = + { + /* Little-endian byte masks for PACKSWAP */ + { B_MASKS(1,0), B_MASKS(2,0), B_MASKS(4,0) }, + /* Normal (big-endian byte) masks - PNG format */ + { B_MASKS(1,1), B_MASKS(2,1), B_MASKS(4,1) } + }; + +# define MASK(pass,depth,display,png)\ + ((display)?display_mask[png][DEPTH_INDEX(depth)][pass>>1]:\ + row_mask[png][DEPTH_INDEX(depth)][pass]) + +#else /* !PNG_USE_COMPILE_TIME_MASKS */ + /* This is the runtime alternative: it seems unlikely that this will + * ever be either smaller or faster than the compile time approach. + */ +# define MASK(pass,depth,display,png)\ + ((display)?B_MASK(pass,depth,png):S_MASK(pass,depth,png)) +#endif /* !USE_COMPILE_TIME_MASKS */ + + /* Use the appropriate mask to copy the required bits. In some cases + * the byte mask will be 0 or 0xff; optimize these cases. row_width is + * the number of pixels, but the code copies bytes, so it is necessary + * to special case the end. + */ + png_uint_32 pixels_per_byte = 8 / pixel_depth; + png_uint_32 mask; + +# ifdef PNG_READ_PACKSWAP_SUPPORTED + if ((png_ptr->transformations & PNG_PACKSWAP) != 0) + mask = MASK(pass, pixel_depth, display, 0); + + else +# endif + mask = MASK(pass, pixel_depth, display, 1); + + for (;;) + { + png_uint_32 m; + + /* It doesn't matter in the following if png_uint_32 has more than + * 32 bits because the high bits always match those in m<<24; it is, + * however, essential to use OR here, not +, because of this. + */ + m = mask; + mask = (m >> 8) | (m << 24); /* rotate right to good compilers */ + m &= 0xff; + + if (m != 0) /* something to copy */ + { + if (m != 0xff) + *dp = (png_byte)((*dp & ~m) | (*sp & m)); + else + *dp = *sp; + } + + /* NOTE: this may overwrite the last byte with garbage if the image + * is not an exact number of bytes wide; libpng has always done + * this. + */ + if (row_width <= pixels_per_byte) + break; /* May need to restore part of the last byte */ + + row_width -= pixels_per_byte; + ++dp; + ++sp; + } + } + + else /* pixel_depth >= 8 */ + { + unsigned int bytes_to_copy, bytes_to_jump; + + /* Validate the depth - it must be a multiple of 8 */ + if (pixel_depth & 7) + png_error(png_ptr, "invalid user transform pixel depth"); + + pixel_depth >>= 3; /* now in bytes */ + row_width *= pixel_depth; + + /* Regardless of pass number the Adam 7 interlace always results in a + * fixed number of pixels to copy then to skip. There may be a + * different number of pixels to skip at the start though. + */ + { + unsigned int offset = PNG_PASS_START_COL(pass) * pixel_depth; + + row_width -= offset; + dp += offset; + sp += offset; + } + + /* Work out the bytes to copy. */ + if (display != 0) + { + /* When doing the 'block' algorithm the pixel in the pass gets + * replicated to adjacent pixels. This is why the even (0,2,4,6) + * passes are skipped above - the entire expanded row is copied. + */ + bytes_to_copy = (1<<((6-pass)>>1)) * pixel_depth; + + /* But don't allow this number to exceed the actual row width. */ + if (bytes_to_copy > row_width) + bytes_to_copy = (unsigned int)/*SAFE*/row_width; + } + + else /* normal row; Adam7 only ever gives us one pixel to copy. */ + bytes_to_copy = pixel_depth; + + /* In Adam7 there is a constant offset between where the pixels go. */ + bytes_to_jump = PNG_PASS_COL_OFFSET(pass) * pixel_depth; + + /* And simply copy these bytes. Some optimization is possible here, + * depending on the value of 'bytes_to_copy'. Special case the low + * byte counts, which we know to be frequent. + * + * Notice that these cases all 'return' rather than 'break' - this + * avoids an unnecessary test on whether to restore the last byte + * below. + */ + switch (bytes_to_copy) + { + case 1: + for (;;) + { + *dp = *sp; + + if (row_width <= bytes_to_jump) + return; + + dp += bytes_to_jump; + sp += bytes_to_jump; + row_width -= bytes_to_jump; + } + + case 2: + /* There is a possibility of a partial copy at the end here; this + * slows the code down somewhat. + */ + do + { + dp[0] = sp[0], dp[1] = sp[1]; + + if (row_width <= bytes_to_jump) + return; + + sp += bytes_to_jump; + dp += bytes_to_jump; + row_width -= bytes_to_jump; + } + while (row_width > 1); + + /* And there can only be one byte left at this point: */ + *dp = *sp; + return; + + case 3: + /* This can only be the RGB case, so each copy is exactly one + * pixel and it is not necessary to check for a partial copy. + */ + for (;;) + { + dp[0] = sp[0], dp[1] = sp[1], dp[2] = sp[2]; + + if (row_width <= bytes_to_jump) + return; + + sp += bytes_to_jump; + dp += bytes_to_jump; + row_width -= bytes_to_jump; + } + + default: +#if PNG_ALIGN_TYPE != PNG_ALIGN_NONE + /* Check for double byte alignment and, if possible, use a + * 16-bit copy. Don't attempt this for narrow images - ones that + * are less than an interlace panel wide. Don't attempt it for + * wide bytes_to_copy either - use the memcpy there. + */ + if (bytes_to_copy < 16 /*else use memcpy*/ && + png_isaligned(dp, png_uint_16) && + png_isaligned(sp, png_uint_16) && + bytes_to_copy % (sizeof (png_uint_16)) == 0 && + bytes_to_jump % (sizeof (png_uint_16)) == 0) + { + /* Everything is aligned for png_uint_16 copies, but try for + * png_uint_32 first. + */ + if (png_isaligned(dp, png_uint_32) != 0 && + png_isaligned(sp, png_uint_32) != 0 && + bytes_to_copy % (sizeof (png_uint_32)) == 0 && + bytes_to_jump % (sizeof (png_uint_32)) == 0) + { + png_uint_32p dp32 = png_aligncast(png_uint_32p,dp); + png_const_uint_32p sp32 = png_aligncastconst( + png_const_uint_32p, sp); + size_t skip = (bytes_to_jump-bytes_to_copy) / + (sizeof (png_uint_32)); + + do + { + size_t c = bytes_to_copy; + do + { + *dp32++ = *sp32++; + c -= (sizeof (png_uint_32)); + } + while (c > 0); + + if (row_width <= bytes_to_jump) + return; + + dp32 += skip; + sp32 += skip; + row_width -= bytes_to_jump; + } + while (bytes_to_copy <= row_width); + + /* Get to here when the row_width truncates the final copy. + * There will be 1-3 bytes left to copy, so don't try the + * 16-bit loop below. + */ + dp = (png_bytep)dp32; + sp = (png_const_bytep)sp32; + do + *dp++ = *sp++; + while (--row_width > 0); + return; + } + + /* Else do it in 16-bit quantities, but only if the size is + * not too large. + */ + else + { + png_uint_16p dp16 = png_aligncast(png_uint_16p, dp); + png_const_uint_16p sp16 = png_aligncastconst( + png_const_uint_16p, sp); + size_t skip = (bytes_to_jump-bytes_to_copy) / + (sizeof (png_uint_16)); + + do + { + size_t c = bytes_to_copy; + do + { + *dp16++ = *sp16++; + c -= (sizeof (png_uint_16)); + } + while (c > 0); + + if (row_width <= bytes_to_jump) + return; + + dp16 += skip; + sp16 += skip; + row_width -= bytes_to_jump; + } + while (bytes_to_copy <= row_width); + + /* End of row - 1 byte left, bytes_to_copy > row_width: */ + dp = (png_bytep)dp16; + sp = (png_const_bytep)sp16; + do + *dp++ = *sp++; + while (--row_width > 0); + return; + } + } +#endif /* ALIGN_TYPE code */ + + /* The true default - use a memcpy: */ + for (;;) + { + memcpy(dp, sp, bytes_to_copy); + + if (row_width <= bytes_to_jump) + return; + + sp += bytes_to_jump; + dp += bytes_to_jump; + row_width -= bytes_to_jump; + if (bytes_to_copy > row_width) + bytes_to_copy = (unsigned int)/*SAFE*/row_width; + } + } + + /* NOT REACHED*/ + } /* pixel_depth >= 8 */ + + /* Here if pixel_depth < 8 to check 'end_ptr' below. */ + } + else +#endif /* READ_INTERLACING */ + + /* If here then the switch above wasn't used so just memcpy the whole row + * from the temporary row buffer (notice that this overwrites the end of the + * destination row if it is a partial byte.) + */ + memcpy(dp, sp, PNG_ROWBYTES(pixel_depth, row_width)); + + /* Restore the overwritten bits from the last byte if necessary. */ + if (end_ptr != NULL) + *end_ptr = (png_byte)((end_byte & end_mask) | (*end_ptr & ~end_mask)); +} + +#ifdef PNG_READ_INTERLACING_SUPPORTED +void /* PRIVATE */ +png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass, + png_uint_32 transformations /* Because these may affect the byte layout */) +{ + /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ + /* Offset to next interlace block */ + static PNG_CONST int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1}; + + png_debug(1, "in png_do_read_interlace"); + if (row != NULL && row_info != NULL) + { + png_uint_32 final_width; + + final_width = row_info->width * png_pass_inc[pass]; + + switch (row_info->pixel_depth) + { + case 1: + { + png_bytep sp = row + (png_size_t)((row_info->width - 1) >> 3); + png_bytep dp = row + (png_size_t)((final_width - 1) >> 3); + int sshift, dshift; + int s_start, s_end, s_inc; + int jstop = png_pass_inc[pass]; + png_byte v; + png_uint_32 i; + int j; + +#ifdef PNG_READ_PACKSWAP_SUPPORTED + if ((transformations & PNG_PACKSWAP) != 0) + { + sshift = (int)((row_info->width + 7) & 0x07); + dshift = (int)((final_width + 7) & 0x07); + s_start = 7; + s_end = 0; + s_inc = -1; + } + + else +#endif + { + sshift = 7 - (int)((row_info->width + 7) & 0x07); + dshift = 7 - (int)((final_width + 7) & 0x07); + s_start = 0; + s_end = 7; + s_inc = 1; + } + + for (i = 0; i < row_info->width; i++) + { + v = (png_byte)((*sp >> sshift) & 0x01); + for (j = 0; j < jstop; j++) + { + unsigned int tmp = *dp & (0x7f7f >> (7 - dshift)); + tmp |= v << dshift; + *dp = (png_byte)(tmp & 0xff); + + if (dshift == s_end) + { + dshift = s_start; + dp--; + } + + else + dshift += s_inc; + } + + if (sshift == s_end) + { + sshift = s_start; + sp--; + } + + else + sshift += s_inc; + } + break; + } + + case 2: + { + png_bytep sp = row + (png_uint_32)((row_info->width - 1) >> 2); + png_bytep dp = row + (png_uint_32)((final_width - 1) >> 2); + int sshift, dshift; + int s_start, s_end, s_inc; + int jstop = png_pass_inc[pass]; + png_uint_32 i; + +#ifdef PNG_READ_PACKSWAP_SUPPORTED + if ((transformations & PNG_PACKSWAP) != 0) + { + sshift = (int)(((row_info->width + 3) & 0x03) << 1); + dshift = (int)(((final_width + 3) & 0x03) << 1); + s_start = 6; + s_end = 0; + s_inc = -2; + } + + else +#endif + { + sshift = (int)((3 - ((row_info->width + 3) & 0x03)) << 1); + dshift = (int)((3 - ((final_width + 3) & 0x03)) << 1); + s_start = 0; + s_end = 6; + s_inc = 2; + } + + for (i = 0; i < row_info->width; i++) + { + png_byte v; + int j; + + v = (png_byte)((*sp >> sshift) & 0x03); + for (j = 0; j < jstop; j++) + { + unsigned int tmp = *dp & (0x3f3f >> (6 - dshift)); + tmp |= v << dshift; + *dp = (png_byte)(tmp & 0xff); + + if (dshift == s_end) + { + dshift = s_start; + dp--; + } + + else + dshift += s_inc; + } + + if (sshift == s_end) + { + sshift = s_start; + sp--; + } + + else + sshift += s_inc; + } + break; + } + + case 4: + { + png_bytep sp = row + (png_size_t)((row_info->width - 1) >> 1); + png_bytep dp = row + (png_size_t)((final_width - 1) >> 1); + int sshift, dshift; + int s_start, s_end, s_inc; + png_uint_32 i; + int jstop = png_pass_inc[pass]; + +#ifdef PNG_READ_PACKSWAP_SUPPORTED + if ((transformations & PNG_PACKSWAP) != 0) + { + sshift = (int)(((row_info->width + 1) & 0x01) << 2); + dshift = (int)(((final_width + 1) & 0x01) << 2); + s_start = 4; + s_end = 0; + s_inc = -4; + } + + else +#endif + { + sshift = (int)((1 - ((row_info->width + 1) & 0x01)) << 2); + dshift = (int)((1 - ((final_width + 1) & 0x01)) << 2); + s_start = 0; + s_end = 4; + s_inc = 4; + } + + for (i = 0; i < row_info->width; i++) + { + png_byte v = (png_byte)((*sp >> sshift) & 0x0f); + int j; + + for (j = 0; j < jstop; j++) + { + unsigned int tmp = *dp & (0xf0f >> (4 - dshift)); + tmp |= v << dshift; + *dp = (png_byte)(tmp & 0xff); + + if (dshift == s_end) + { + dshift = s_start; + dp--; + } + + else + dshift += s_inc; + } + + if (sshift == s_end) + { + sshift = s_start; + sp--; + } + + else + sshift += s_inc; + } + break; + } + + default: + { + png_size_t pixel_bytes = (row_info->pixel_depth >> 3); + + png_bytep sp = row + (png_size_t)(row_info->width - 1) + * pixel_bytes; + + png_bytep dp = row + (png_size_t)(final_width - 1) * pixel_bytes; + + int jstop = png_pass_inc[pass]; + png_uint_32 i; + + for (i = 0; i < row_info->width; i++) + { + png_byte v[8]; /* SAFE; pixel_depth does not exceed 64 */ + int j; + + memcpy(v, sp, pixel_bytes); + + for (j = 0; j < jstop; j++) + { + memcpy(dp, v, pixel_bytes); + dp -= pixel_bytes; + } + + sp -= pixel_bytes; + } + break; + } + } + + row_info->width = final_width; + row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, final_width); + } +#ifndef PNG_READ_PACKSWAP_SUPPORTED + PNG_UNUSED(transformations) /* Silence compiler warning */ +#endif +} +#endif /* READ_INTERLACING */ + +static void +png_read_filter_row_sub(png_row_infop row_info, png_bytep row, + png_const_bytep prev_row) +{ + png_size_t i; + png_size_t istop = row_info->rowbytes; + unsigned int bpp = (row_info->pixel_depth + 7) >> 3; + png_bytep rp = row + bpp; + + PNG_UNUSED(prev_row) + + for (i = bpp; i < istop; i++) + { + *rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 0xff); + rp++; + } +} + +static void +png_read_filter_row_up(png_row_infop row_info, png_bytep row, + png_const_bytep prev_row) +{ + png_size_t i; + png_size_t istop = row_info->rowbytes; + png_bytep rp = row; + png_const_bytep pp = prev_row; + + for (i = 0; i < istop; i++) + { + *rp = (png_byte)(((int)(*rp) + (int)(*pp++)) & 0xff); + rp++; + } +} + +static void +png_read_filter_row_avg(png_row_infop row_info, png_bytep row, + png_const_bytep prev_row) +{ + png_size_t i; + png_bytep rp = row; + png_const_bytep pp = prev_row; + unsigned int bpp = (row_info->pixel_depth + 7) >> 3; + png_size_t istop = row_info->rowbytes - bpp; + + for (i = 0; i < bpp; i++) + { + *rp = (png_byte)(((int)(*rp) + + ((int)(*pp++) / 2 )) & 0xff); + + rp++; + } + + for (i = 0; i < istop; i++) + { + *rp = (png_byte)(((int)(*rp) + + (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff); + + rp++; + } +} + +static void +png_read_filter_row_paeth_1byte_pixel(png_row_infop row_info, png_bytep row, + png_const_bytep prev_row) +{ + png_bytep rp_end = row + row_info->rowbytes; + int a, c; + + /* First pixel/byte */ + c = *prev_row++; + a = *row + c; + *row++ = (png_byte)a; + + /* Remainder */ + while (row < rp_end) + { + int b, pa, pb, pc, p; + + a &= 0xff; /* From previous iteration or start */ + b = *prev_row++; + + p = b - c; + pc = a - c; + +#ifdef PNG_USE_ABS + pa = abs(p); + pb = abs(pc); + pc = abs(p + pc); +#else + pa = p < 0 ? -p : p; + pb = pc < 0 ? -pc : pc; + pc = (p + pc) < 0 ? -(p + pc) : p + pc; +#endif + + /* Find the best predictor, the least of pa, pb, pc favoring the earlier + * ones in the case of a tie. + */ + if (pb < pa) pa = pb, a = b; + if (pc < pa) a = c; + + /* Calculate the current pixel in a, and move the previous row pixel to c + * for the next time round the loop + */ + c = b; + a += *row; + *row++ = (png_byte)a; + } +} + +static void +png_read_filter_row_paeth_multibyte_pixel(png_row_infop row_info, png_bytep row, + png_const_bytep prev_row) +{ + int bpp = (row_info->pixel_depth + 7) >> 3; + png_bytep rp_end = row + bpp; + + /* Process the first pixel in the row completely (this is the same as 'up' + * because there is only one candidate predictor for the first row). + */ + while (row < rp_end) + { + int a = *row + *prev_row++; + *row++ = (png_byte)a; + } + + /* Remainder */ + rp_end += row_info->rowbytes - bpp; + + while (row < rp_end) + { + int a, b, c, pa, pb, pc, p; + + c = *(prev_row - bpp); + a = *(row - bpp); + b = *prev_row++; + + p = b - c; + pc = a - c; + +#ifdef PNG_USE_ABS + pa = abs(p); + pb = abs(pc); + pc = abs(p + pc); +#else + pa = p < 0 ? -p : p; + pb = pc < 0 ? -pc : pc; + pc = (p + pc) < 0 ? -(p + pc) : p + pc; +#endif + + if (pb < pa) pa = pb, a = b; + if (pc < pa) a = c; + + a += *row; + *row++ = (png_byte)a; + } +} + +static void +png_init_filter_functions(png_structrp pp) + /* This function is called once for every PNG image (except for PNG images + * that only use PNG_FILTER_VALUE_NONE for all rows) to set the + * implementations required to reverse the filtering of PNG rows. Reversing + * the filter is the first transformation performed on the row data. It is + * performed in place, therefore an implementation can be selected based on + * the image pixel format. If the implementation depends on image width then + * take care to ensure that it works correctly if the image is interlaced - + * interlacing causes the actual row width to vary. + */ +{ + unsigned int bpp = (pp->pixel_depth + 7) >> 3; + + pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub; + pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up; + pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg; + if (bpp == 1) + pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = + png_read_filter_row_paeth_1byte_pixel; + else + pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = + png_read_filter_row_paeth_multibyte_pixel; + +#ifdef PNG_FILTER_OPTIMIZATIONS + /* To use this define PNG_FILTER_OPTIMIZATIONS as the name of a function to + * call to install hardware optimizations for the above functions; simply + * replace whatever elements of the pp->read_filter[] array with a hardware + * specific (or, for that matter, generic) optimization. + * + * To see an example of this examine what configure.ac does when + * --enable-arm-neon is specified on the command line. + */ + PNG_FILTER_OPTIMIZATIONS(pp, bpp); +#endif +} + +void /* PRIVATE */ +png_read_filter_row(png_structrp pp, png_row_infop row_info, png_bytep row, + png_const_bytep prev_row, int filter) +{ + /* OPTIMIZATION: DO NOT MODIFY THIS FUNCTION, instead #define + * PNG_FILTER_OPTIMIZATIONS to a function that overrides the generic + * implementations. See png_init_filter_functions above. + */ + if (filter > PNG_FILTER_VALUE_NONE && filter < PNG_FILTER_VALUE_LAST) + { + if (pp->read_filter[0] == NULL) + png_init_filter_functions(pp); + + pp->read_filter[filter-1](row_info, row, prev_row); + } +} + +#ifdef PNG_SEQUENTIAL_READ_SUPPORTED +void /* PRIVATE */ +png_read_IDAT_data(png_structrp png_ptr, png_bytep output, + png_alloc_size_t avail_out) +{ + /* Loop reading IDATs and decompressing the result into output[avail_out] */ + png_ptr->zstream.next_out = output; + png_ptr->zstream.avail_out = 0; /* safety: set below */ + + if (output == NULL) + avail_out = 0; + + do + { + int ret; + png_byte tmpbuf[PNG_INFLATE_BUF_SIZE]; + + if (png_ptr->zstream.avail_in == 0) + { + uInt avail_in; + png_bytep buffer; + + while (png_ptr->idat_size == 0) + { + png_crc_finish(png_ptr, 0); + + png_ptr->idat_size = png_read_chunk_header(png_ptr); + /* This is an error even in the 'check' case because the code just + * consumed a non-IDAT header. + */ + if (png_ptr->chunk_name != png_IDAT) + png_error(png_ptr, "Not enough image data"); + } + + avail_in = png_ptr->IDAT_read_size; + + if (avail_in > png_ptr->idat_size) + avail_in = (uInt)png_ptr->idat_size; + + /* A PNG with a gradually increasing IDAT size will defeat this attempt + * to minimize memory usage by causing lots of re-allocs, but + * realistically doing IDAT_read_size re-allocs is not likely to be a + * big problem. + */ + buffer = png_read_buffer(png_ptr, avail_in, 0/*error*/); + + png_crc_read(png_ptr, buffer, avail_in); + png_ptr->idat_size -= avail_in; + + png_ptr->zstream.next_in = buffer; + png_ptr->zstream.avail_in = avail_in; + } + + /* And set up the output side. */ + if (output != NULL) /* standard read */ + { + uInt out = ZLIB_IO_MAX; + + if (out > avail_out) + out = (uInt)avail_out; + + avail_out -= out; + png_ptr->zstream.avail_out = out; + } + + else /* after last row, checking for end */ + { + png_ptr->zstream.next_out = tmpbuf; + png_ptr->zstream.avail_out = (sizeof tmpbuf); + } + + /* Use NO_FLUSH; this gives zlib the maximum opportunity to optimize the + * process. If the LZ stream is truncated the sequential reader will + * terminally damage the stream, above, by reading the chunk header of the + * following chunk (it then exits with png_error). + * + * TODO: deal more elegantly with truncated IDAT lists. + */ + ret = PNG_INFLATE(png_ptr, Z_NO_FLUSH); + + /* Take the unconsumed output back. */ + if (output != NULL) + avail_out += png_ptr->zstream.avail_out; + + else /* avail_out counts the extra bytes */ + avail_out += (sizeof tmpbuf) - png_ptr->zstream.avail_out; + + png_ptr->zstream.avail_out = 0; + + if (ret == Z_STREAM_END) + { + /* Do this for safety; we won't read any more into this row. */ + png_ptr->zstream.next_out = NULL; + + png_ptr->mode |= PNG_AFTER_IDAT; + png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED; + + if (png_ptr->zstream.avail_in > 0 || png_ptr->idat_size > 0) + png_chunk_benign_error(png_ptr, "Extra compressed data"); + break; + } + + if (ret != Z_OK) + { + png_zstream_error(png_ptr, ret); + + if (output != NULL) + png_chunk_error(png_ptr, png_ptr->zstream.msg); + + else /* checking */ + { + png_chunk_benign_error(png_ptr, png_ptr->zstream.msg); + return; + } + } + } while (avail_out > 0); + + if (avail_out > 0) + { + /* The stream ended before the image; this is the same as too few IDATs so + * should be handled the same way. + */ + if (output != NULL) + png_error(png_ptr, "Not enough image data"); + + else /* the deflate stream contained extra data */ + png_chunk_benign_error(png_ptr, "Too much image data"); + } +} + +void /* PRIVATE */ +png_read_finish_IDAT(png_structrp png_ptr) +{ + /* We don't need any more data and the stream should have ended, however the + * LZ end code may actually not have been processed. In this case we must + * read it otherwise stray unread IDAT data or, more likely, an IDAT chunk + * may still remain to be consumed. + */ + if ((png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0) + { + /* The NULL causes png_read_IDAT_data to swallow any remaining bytes in + * the compressed stream, but the stream may be damaged too, so even after + * this call we may need to terminate the zstream ownership. + */ + png_read_IDAT_data(png_ptr, NULL, 0); + png_ptr->zstream.next_out = NULL; /* safety */ + + /* Now clear everything out for safety; the following may not have been + * done. + */ + if ((png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0) + { + png_ptr->mode |= PNG_AFTER_IDAT; + png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED; + } + } + + /* If the zstream has not been released do it now *and* terminate the reading + * of the final IDAT chunk. + */ + if (png_ptr->zowner == png_IDAT) + { + /* Always do this; the pointers otherwise point into the read buffer. */ + png_ptr->zstream.next_in = NULL; + png_ptr->zstream.avail_in = 0; + + /* Now we no longer own the zstream. */ + png_ptr->zowner = 0; + + /* The slightly weird semantics of the sequential IDAT reading is that we + * are always in or at the end of an IDAT chunk, so we always need to do a + * crc_finish here. If idat_size is non-zero we also need to read the + * spurious bytes at the end of the chunk now. + */ + (void)png_crc_finish(png_ptr, png_ptr->idat_size); + } +} + +void /* PRIVATE */ +png_read_finish_row(png_structrp png_ptr) +{ + /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ + + /* Start of interlace block */ + static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0}; + + /* Offset to next interlace block */ + static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1}; + + /* Start of interlace block in the y direction */ + static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1}; + + /* Offset to next interlace block in the y direction */ + static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2}; + + png_debug(1, "in png_read_finish_row"); + png_ptr->row_number++; + if (png_ptr->row_number < png_ptr->num_rows) + return; + + if (png_ptr->interlaced != 0) + { + png_ptr->row_number = 0; + + /* TO DO: don't do this if prev_row isn't needed (requires + * read-ahead of the next row's filter byte. + */ + memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1); + + do + { + png_ptr->pass++; + + if (png_ptr->pass >= 7) + break; + + png_ptr->iwidth = (png_ptr->width + + png_pass_inc[png_ptr->pass] - 1 - + png_pass_start[png_ptr->pass]) / + png_pass_inc[png_ptr->pass]; + + if ((png_ptr->transformations & PNG_INTERLACE) == 0) + { + png_ptr->num_rows = (png_ptr->height + + png_pass_yinc[png_ptr->pass] - 1 - + png_pass_ystart[png_ptr->pass]) / + png_pass_yinc[png_ptr->pass]; + } + + else /* if (png_ptr->transformations & PNG_INTERLACE) */ + break; /* libpng deinterlacing sees every row */ + + } while (png_ptr->num_rows == 0 || png_ptr->iwidth == 0); + + if (png_ptr->pass < 7) + return; + } + + /* Here after at the end of the last row of the last pass. */ + png_read_finish_IDAT(png_ptr); +} +#endif /* SEQUENTIAL_READ */ + +void /* PRIVATE */ +png_read_start_row(png_structrp png_ptr) +{ + /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ + + /* Start of interlace block */ + static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0}; + + /* Offset to next interlace block */ + static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1}; + + /* Start of interlace block in the y direction */ + static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1}; + + /* Offset to next interlace block in the y direction */ + static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2}; + + int max_pixel_depth; + png_size_t row_bytes; + + png_debug(1, "in png_read_start_row"); + +#ifdef PNG_READ_TRANSFORMS_SUPPORTED + png_init_read_transformations(png_ptr); +#endif + if (png_ptr->interlaced != 0) + { + if ((png_ptr->transformations & PNG_INTERLACE) == 0) + png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 - + png_pass_ystart[0]) / png_pass_yinc[0]; + + else + png_ptr->num_rows = png_ptr->height; + + png_ptr->iwidth = (png_ptr->width + + png_pass_inc[png_ptr->pass] - 1 - + png_pass_start[png_ptr->pass]) / + png_pass_inc[png_ptr->pass]; + } + + else + { + png_ptr->num_rows = png_ptr->height; + png_ptr->iwidth = png_ptr->width; + } + + max_pixel_depth = png_ptr->pixel_depth; + + /* WARNING: * png_read_transform_info (pngrtran.c) performs a simpler set of + * calculations to calculate the final pixel depth, then + * png_do_read_transforms actually does the transforms. This means that the + * code which effectively calculates this value is actually repeated in three + * separate places. They must all match. Innocent changes to the order of + * transformations can and will break libpng in a way that causes memory + * overwrites. + * + * TODO: fix this. + */ +#ifdef PNG_READ_PACK_SUPPORTED + if ((png_ptr->transformations & PNG_PACK) != 0 && png_ptr->bit_depth < 8) + max_pixel_depth = 8; +#endif + +#ifdef PNG_READ_EXPAND_SUPPORTED + if ((png_ptr->transformations & PNG_EXPAND) != 0) + { + if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) + { + if (png_ptr->num_trans != 0) + max_pixel_depth = 32; + + else + max_pixel_depth = 24; + } + + else if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY) + { + if (max_pixel_depth < 8) + max_pixel_depth = 8; + + if (png_ptr->num_trans != 0) + max_pixel_depth *= 2; + } + + else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB) + { + if (png_ptr->num_trans != 0) + { + max_pixel_depth *= 4; + max_pixel_depth /= 3; + } + } + } +#endif + +#ifdef PNG_READ_EXPAND_16_SUPPORTED + if ((png_ptr->transformations & PNG_EXPAND_16) != 0) + { +# ifdef PNG_READ_EXPAND_SUPPORTED + /* In fact it is an error if it isn't supported, but checking is + * the safe way. + */ + if ((png_ptr->transformations & PNG_EXPAND) != 0) + { + if (png_ptr->bit_depth < 16) + max_pixel_depth *= 2; + } + else +# endif + png_ptr->transformations &= ~PNG_EXPAND_16; + } +#endif + +#ifdef PNG_READ_FILLER_SUPPORTED + if ((png_ptr->transformations & (PNG_FILLER)) != 0) + { + if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY) + { + if (max_pixel_depth <= 8) + max_pixel_depth = 16; + + else + max_pixel_depth = 32; + } + + else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB || + png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) + { + if (max_pixel_depth <= 32) + max_pixel_depth = 32; + + else + max_pixel_depth = 64; + } + } +#endif + +#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED + if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0) + { + if ( +#ifdef PNG_READ_EXPAND_SUPPORTED + (png_ptr->num_trans != 0 && + (png_ptr->transformations & PNG_EXPAND) != 0) || +#endif +#ifdef PNG_READ_FILLER_SUPPORTED + (png_ptr->transformations & (PNG_FILLER)) != 0 || +#endif + png_ptr->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) + { + if (max_pixel_depth <= 16) + max_pixel_depth = 32; + + else + max_pixel_depth = 64; + } + + else + { + if (max_pixel_depth <= 8) + { + if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA) + max_pixel_depth = 32; + + else + max_pixel_depth = 24; + } + + else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA) + max_pixel_depth = 64; + + else + max_pixel_depth = 48; + } + } +#endif + +#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) && \ +defined(PNG_USER_TRANSFORM_PTR_SUPPORTED) + if ((png_ptr->transformations & PNG_USER_TRANSFORM) != 0) + { + int user_pixel_depth = png_ptr->user_transform_depth * + png_ptr->user_transform_channels; + + if (user_pixel_depth > max_pixel_depth) + max_pixel_depth = user_pixel_depth; + } +#endif + + /* This value is stored in png_struct and double checked in the row read + * code. + */ + png_ptr->maximum_pixel_depth = (png_byte)max_pixel_depth; + png_ptr->transformed_pixel_depth = 0; /* calculated on demand */ + + /* Align the width on the next larger 8 pixels. Mainly used + * for interlacing + */ + row_bytes = ((png_ptr->width + 7) & ~((png_uint_32)7)); + /* Calculate the maximum bytes needed, adding a byte and a pixel + * for safety's sake + */ + row_bytes = PNG_ROWBYTES(max_pixel_depth, row_bytes) + + 1 + ((max_pixel_depth + 7) >> 3); + +#ifdef PNG_MAX_MALLOC_64K + if (row_bytes > (png_uint_32)65536L) + png_error(png_ptr, "This image requires a row greater than 64KB"); +#endif + + if (row_bytes + 48 > png_ptr->old_big_row_buf_size) + { + png_free(png_ptr, png_ptr->big_row_buf); + png_free(png_ptr, png_ptr->big_prev_row); + + if (png_ptr->interlaced != 0) + png_ptr->big_row_buf = (png_bytep)png_calloc(png_ptr, + row_bytes + 48); + + else + png_ptr->big_row_buf = (png_bytep)png_malloc(png_ptr, row_bytes + 48); + + png_ptr->big_prev_row = (png_bytep)png_malloc(png_ptr, row_bytes + 48); + +#ifdef PNG_ALIGNED_MEMORY_SUPPORTED + /* Use 16-byte aligned memory for row_buf with at least 16 bytes + * of padding before and after row_buf; treat prev_row similarly. + * NOTE: the alignment is to the start of the pixels, one beyond the start + * of the buffer, because of the filter byte. Prior to libpng 1.5.6 this + * was incorrect; the filter byte was aligned, which had the exact + * opposite effect of that intended. + */ + { + png_bytep temp = png_ptr->big_row_buf + 32; + int extra = (int)((temp - (png_bytep)0) & 0x0f); + png_ptr->row_buf = temp - extra - 1/*filter byte*/; + + temp = png_ptr->big_prev_row + 32; + extra = (int)((temp - (png_bytep)0) & 0x0f); + png_ptr->prev_row = temp - extra - 1/*filter byte*/; + } + +#else + /* Use 31 bytes of padding before and 17 bytes after row_buf. */ + png_ptr->row_buf = png_ptr->big_row_buf + 31; + png_ptr->prev_row = png_ptr->big_prev_row + 31; +#endif + png_ptr->old_big_row_buf_size = row_bytes + 48; + } + +#ifdef PNG_MAX_MALLOC_64K + if (png_ptr->rowbytes > 65535) + png_error(png_ptr, "This image requires a row greater than 64KB"); + +#endif + if (png_ptr->rowbytes > (PNG_SIZE_MAX - 1)) + png_error(png_ptr, "Row has too many bytes to allocate in memory"); + + memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1); + + png_debug1(3, "width = %u,", png_ptr->width); + png_debug1(3, "height = %u,", png_ptr->height); + png_debug1(3, "iwidth = %u,", png_ptr->iwidth); + png_debug1(3, "num_rows = %u,", png_ptr->num_rows); + png_debug1(3, "rowbytes = %lu,", (unsigned long)png_ptr->rowbytes); + png_debug1(3, "irowbytes = %lu", + (unsigned long)PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->iwidth) + 1); + + /* The sequential reader needs a buffer for IDAT, but the progressive reader + * does not, so free the read buffer now regardless; the sequential reader + * reallocates it on demand. + */ + if (png_ptr->read_buffer != 0) + { + png_bytep buffer = png_ptr->read_buffer; + + png_ptr->read_buffer_size = 0; + png_ptr->read_buffer = NULL; + png_free(png_ptr, buffer); + } + + /* Finally claim the zstream for the inflate of the IDAT data, use the bits + * value from the stream (note that this will result in a fatal error if the + * IDAT stream has a bogus deflate header window_bits value, but this should + * not be happening any longer!) + */ + if (png_inflate_claim(png_ptr, png_IDAT) != Z_OK) + png_error(png_ptr, png_ptr->zstream.msg); + + png_ptr->flags |= PNG_FLAG_ROW_INIT; +} +#endif /* READ */ |