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[libpng16] Moved chunk-length check into a png_check_chunk_length() private

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function (Suggested by Max Stepin).
This commit is contained in:
Glenn Randers-Pehrson
2017-08-04 14:09:27 -05:00
parent 469317d9bd
commit 2dca15686f
5 changed files with 51 additions and 66 deletions
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34
pngpread.c
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@@ -190,6 +190,8 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
png_crc_read(png_ptr, chunk_tag, 4);
png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(chunk_tag);
png_check_chunk_name(png_ptr, png_ptr->chunk_name);
png_check_chunk_length(png_ptr, png_ptr->chunk_name,
png_ptr->push_length);
png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
}
@@ -224,38 +226,6 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
png_benign_error(png_ptr, "Too many IDATs found");
}
if (chunk_name == png_IDAT)
{
size_t row_factor =
(png_ptr->width * png_ptr->channels * (png_ptr->bit_depth > 8? 2: 1)
+ 1 + (png_ptr->interlaced? 6: 0));
if (png_ptr->height > PNG_UINT_32_MAX/row_factor)
limit=PNG_UINT_31_MAX;
else
limit = png_ptr->height * row_factor;
limit += 6 + 5*(limit/32566+1); /* zlib+deflate overhead */
limit=limit < PNG_UINT_31_MAX? limit : PNG_UINT_31_MAX;
}
else
{
# ifdef PNG_SET_USER_LIMITS_SUPPORTED
if (png_ptr->user_chunk_malloc_max > 0 &&
png_ptr->user_chunk_malloc_max < limit)
limit = png_ptr->user_chunk_malloc_max;
# elif PNG_USER_CHUNK_MALLOC_MAX > 0
if (PNG_USER_CHUNK_MALLOC_MAX < limit)
limit = PNG_USER_CHUNK_MALLOC_MAX;
# endif
}
if (png_ptr->push_length > limit)
{
printf(" png_ptr->push_length = %lu, limit = %lu\n",
(unsigned long)png_ptr->push_length,(unsigned long)limit);
png_debug2(0," png_ptr->push_length = %lu, limit = %lu",
(unsigned long)png_ptr->push_length,(unsigned long)limit);
png_chunk_error(png_ptr, "chunk data is too large");
}
if (chunk_name == png_IHDR)
{
if (png_ptr->push_length != 13)