Return io::Error if failed to decode distance code width table

This resolves RazrFalcon/usvg#21
sile · Jul 1, 2018 · 6157daa · 6157daa
1 parent 258cf44
commit 6157daa
Showing 1 changed file with 8 additions and 1 deletion.
diff --git a/src/deflate/symbol.rs b/src/deflate/symbol.rs
@@ -399,7 +399,14 @@ impl HuffmanCodec for DynamicHuffmanCodec {
                 .or_else(|| literal_code_bitwidthes.last().cloned());
             distance_code_bitwidthes.extend(load_bitwidthes(reader, c, last)?);
         }
-        debug_assert_eq!(distance_code_bitwidthes.len(), distance_code_count as usize);
+        if distance_code_bitwidthes.len() > distance_code_count as usize {
+            let message = format!(
+                "The length of `distance_code_bitwidthes` is too large: actual={}, expected={}",
+                distance_code_bitwidthes.len(),
+                distance_code_count
+            );
+            return Err(io::Error::new(io::ErrorKind::InvalidData, message));
+        }
 
         Ok(Decoder {
             literal: huffman::DecoderBuilder::from_bitwidthes(