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[libpng12] Prevent writing over-length PLTE chunk (Cosmin Truta) and

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silently truncate over-length PLTE chunk while reading.
This commit is contained in:
Glenn Randers-Pehrson
2015-10-31 08:39:01 -05:00
parent 856a76b285
commit 475bab6170
4 changed files with 29 additions and 10 deletions
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13
pngset.c
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@@ -1,7 +1,7 @@
/* pngset.c - storage of image information into info struct
*
* Last changed in libpng 1.2.53 [February 26, 2015]
* Last changed in libpng 1.2.54 [October 31, 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.)
@@ -449,12 +449,17 @@ png_set_PLTE(png_structp png_ptr, png_infop info_ptr,
png_colorp palette, int num_palette)
{
png_uint_32 max_palette_length;
png_debug1(1, "in %s storage function", "PLTE");
if (png_ptr == NULL || info_ptr == NULL)
return;
if (num_palette < 0 || num_palette > PNG_MAX_PALETTE_LENGTH)
max_palette_length = (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) ?
(1 << png_ptr->bit_depth) : PNG_MAX_PALETTE_LENGTH;
if (num_palette < 0 || num_palette > (int) max_palette_length)
{
if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
png_error(png_ptr, "Invalid palette length");
@@ -474,8 +479,8 @@ png_set_PLTE(png_structp png_ptr, png_infop info_ptr,
#endif
/* Changed in libpng-1.2.1 to allocate PNG_MAX_PALETTE_LENGTH instead
* of num_palette entries, in case of an invalid PNG file that has
* too-large sample values.
* of num_palette entries, in case of an invalid PNG file or incorrect
* call to png_set_PLTE() with too-large sample values.
*/
png_ptr->palette = (png_colorp)png_calloc(png_ptr,
PNG_MAX_PALETTE_LENGTH * png_sizeof(png_color));