libpng: update to 1.2.45

third_party/libpng/pngrutil.c

Index: third_party/libpng/pngrutil.c
diff --git a/third_party/libpng/pngrutil.c b/third_party/libpng/pngrutil.c
index 1e2db31b25b7cf30f460e52b6fa1302e4cdcea90..45e7dddfcf5e49c0b903989f3224a1073b9bce0c 100644
--- a/third_party/libpng/pngrutil.c
+++ b/third_party/libpng/pngrutil.c
@@ -1,8 +1,8 @@
 
 /* pngrutil.c - utilities to read a PNG file
  *
- * Last changed in libpng 1.2.44 [June 26, 2010]
- * Copyright (c) 1998-2010 Glenn Randers-Pehrson
+ * Last changed in libpng 1.2.45 [July 7, 2011]
+ * Copyright (c) 1998-2011 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.)
  *
@@ -1812,6 +1812,14 @@ png_handle_sCAL(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
       return;
    }
 
+   /* Need unit type, width, \0, height: minimum 4 bytes */
+   else if (length < 4)
+   {
+      png_warning(png_ptr, "sCAL chunk too short");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+
    png_debug1(2, "Allocating and reading sCAL chunk data (%lu bytes)",
       length + 1);
    png_ptr->chunkdata = (png_charp)png_malloc_warn(png_ptr, length + 1);