From 9821583a771bfe2c75b7449d8ff83cb348291b3f Mon Sep 17 00:00:00 2001

From: Cosmin Truta <ctruta@gmail.com>

Date: Sun, 17 Jun 2018 22:56:29 -0400

Subject: [PATCH] Fix the calculation of row_factor in png_check_chunk_length

(Bug report by Thuan Pham, SourceForge issue #278)

---

 pngrutil.c | 9 ++++++---

 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/pngrutil.c b/pngrutil.c

index 8692933..eab2973 100644

--- a/pngrutil.c

+++ b/pngrutil.c

@@ -3149,10 +3149,13 @@ png_check_chunk_length(png_const_structrp png_ptr, const png_uint_32 length)

    {

       png_alloc_size_t idat_limit = PNG_UINT_31_MAX;

       size_t row_factor =

-         (png_ptr->width * png_ptr->channels * (png_ptr->bit_depth > 8? 2: 1)

-          + 1 + (png_ptr->interlaced? 6: 0));

+         (size_t)png_ptr->width

+         * (size_t)png_ptr->channels

+         * (png_ptr->bit_depth > 8? 2: 1)

+         + 1

+         + (png_ptr->interlaced? 6: 0);

       if (png_ptr->height > PNG_UINT_32_MAX/row_factor)

-         idat_limit=PNG_UINT_31_MAX;

+         idat_limit = PNG_UINT_31_MAX;

       else

          idat_limit = png_ptr->height * row_factor;

       row_factor = row_factor > 32566? 32566 : row_factor;

-- 

2.17.1