protect against invalid chunk lengths in some tools

1 files changed, 4 insertions, 0 deletions

diff --git a/example_png_info.cpp b/example_png_info.cpp
index 86f664a..e7f78a2 100644
--- a/example_png_info.cpp
+++ b/example_png_info.cpp
@@ -232,6 +232,10 @@ void displayFilterTypes(const std::vector<unsigned char>& buffer)
     {
       const unsigned char* cdata = lodepng_chunk_data_const(chunk);
       unsigned clength = lodepng_chunk_length(chunk);
+      if(chunk + clength >= end) {
+        std::cout << "invalid chunk length" << std::endl;
+        return;
+      }
 
       for(unsigned i = 0; i < clength; i++)
       {