From 3789cba2f2fa0c8674b737887d8fe6172deeaa68 Mon Sep 17 00:00:00 2001
From: Glenn Randers-Pehrson <glennrp at users.sourceforge.net>
Date: Fri, 8 Sep 2017 09:34:08 -0500
Subject: [PATCH] [libpng16] Attempt to isolate an oss-fuzz issue in
 png_set_text_2

---
 png.c    |  2 +-
 pngset.c | 12 ++++++++++--
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/png.c b/png.c
index d324cd791..866395ede 100644
--- a/png.c
+++ b/png.c
@@ -1,7 +1,7 @@
 
 /* png.c - location for general purpose libpng functions
  *
- * Last changed in libpng 1.6.32 [August 24, 2017]
+ * Last changed in libpng 1.6.33 [(PENDING RELEASE)]
  * Copyright (c) 1998-2002,2004,2006-2017 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.)
diff --git a/pngset.c b/pngset.c
index 6f3a1ee11..6d441049f 100644
--- a/pngset.c
+++ b/pngset.c
@@ -1,7 +1,7 @@
 
 /* pngset.c - storage of image information into info struct
  *
- * Last changed in libpng 1.6.32 [August 24, 2017]
+ * Last changed in libpng 1.6.33 [(PENDING RELEASE)]
  * Copyright (c) 1998-2017 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.)
@@ -837,6 +837,9 @@ png_set_text_2(png_const_structrp png_ptr, png_inforp info_ptr,
       size_t lang_len, lang_key_len;
       png_textp textp = &(info_ptr->text[info_ptr->num_text]);
 
+      int text_is_null=0;
+      int text_0_is_0=0;
+
       if (text_ptr[i].key == NULL)
           continue;
 
@@ -881,7 +884,12 @@ png_set_text_2(png_const_structrp png_ptr, png_inforp info_ptr,
       }
 #  endif
 
-      if (text_ptr[i].text == NULL || text_ptr[i].text[0] == '\0')
+      if (text_ptr[i].text == NULL)
+         text_is_null=1;
+      if (text_ptr[i].text[0] == '\0')
+         text_0_is_0=1;
+
+      if (text_is_null || text_0_is_0)
       {
          text_length = 0;
 #  ifdef PNG_iTXt_SUPPORTED