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From 94899f849e50a765bb26420f5c70d49002d6673f Mon Sep 17 00:00:00 2001
From: Glenn Randers-Pehrson <glennrp+bmo@gmail.com>
Date: Mon, 26 Jan 2015 16:07:00 -0500
Subject: [PATCH] Bug 1117406 - Fix handling of out-of-range PNG tRNS values.
r=jmuizelaar, a=abillings
---
image/decoders/nsPNGDecoder.cpp | 22 ++++++++++++----------
1 file changed, 12 insertions(+), 10 deletions(-)
diff --git a/image/decoders/nsPNGDecoder.cpp b/image/decoders/nsPNGDecoder.cpp
index acaa835..8e6bc2d 100644
--- a/image/decoders/nsPNGDecoder.cpp
+++ b/image/decoders/nsPNGDecoder.cpp
@@ -528,24 +528,26 @@ nsPNGDecoder::info_callback(png_structp png_ptr, png_infop info_ptr)
png_set_expand(png_ptr);
if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) {
- int sample_max = (1 << bit_depth);
png_color_16p trans_values;
png_get_tRNS(png_ptr, info_ptr, &trans, &num_trans, &trans_values);
/* libpng doesn't reject a tRNS chunk with out-of-range samples
so we check it here to avoid setting up a useless opacity
- channel or producing unexpected transparent pixels when using
- libpng-1.2.19 through 1.2.26 (bug #428045) */
- if ((color_type == PNG_COLOR_TYPE_GRAY &&
- (int)trans_values->gray > sample_max) ||
- (color_type == PNG_COLOR_TYPE_RGB &&
- ((int)trans_values->red > sample_max ||
- (int)trans_values->green > sample_max ||
- (int)trans_values->blue > sample_max)))
+ channel or producing unexpected transparent pixels (bug #428045) */
+ if (bit_depth < 16) {
+ png_uint_16 sample_max = (1 << bit_depth) - 1;
+ if ((color_type == PNG_COLOR_TYPE_GRAY &&
+ trans_values->gray > sample_max) ||
+ (color_type == PNG_COLOR_TYPE_RGB &&
+ (trans_values->red > sample_max ||
+ trans_values->green > sample_max ||
+ trans_values->blue > sample_max)))
{
/* clear the tRNS valid flag and release tRNS memory */
png_free_data(png_ptr, info_ptr, PNG_FREE_TRNS, 0);
+ num_trans = 0;
}
- else
+ }
+ if (num_trans != 0)
png_set_expand(png_ptr);
}
--
2.2.1