Merge pull request #26 from anatawa12/issue-25

Fix panic with debug build with big copy length

CHANGELOG.md

@@ -16,6 +16,7 @@ The format is based on [Keep a Changelog].
 ### Removed
 
 ### Fixed
+- Panic with Invalid Data `#26` `#24`
 
 ### Security
 

src/inflater_managed.rs

@@ -33,6 +33,10 @@ static STATIC_DISTANCE_TREE_TABLE: &[u8] = &[
     0x01, 0x11, 0x09, 0x19, 0x05, 0x15, 0x0d, 0x1d, 0x03, 0x13, 0x0b, 0x1b, 0x07, 0x17, 0x0f, 0x1f,
 ];
 
+// source: https://github.com/dotnet/runtime/blob/82dac28143be0740d795f434db9b70f61b3b7a04/src/libraries/System.IO.Compression/src/System/IO/Compression/DeflateManaged/OutputWindow.cs#L17
+const TABLE_LOOKUP_LENGTH_MAX: usize = 65536;
+const TABLE_LOOKUP_DISTANCE_MAX: usize = 65538;
+
 /// The streaming Inflater for deflate64
 ///
 /// This struct has big buffer so It's not recommended to move this struct.
@@ -326,7 +330,7 @@ impl InflaterManaged {
         *end_of_block_code_seen = false;
 
         let mut free_bytes = self.output.free_bytes(); // it is a little bit faster than frequently accessing the property
-        while free_bytes > 65536 {
+        while free_bytes > TABLE_LOOKUP_LENGTH_MAX {
             // With Deflate64 we can have up to a 64kb length, so we ensure at least that much space is available
             // in the OutputWindow to avoid overwriting previous unflushed output data.
 
@@ -412,6 +416,10 @@ impl InflaterManaged {
                         offset = (self.distance_code + 1) as usize;
                     }
 
+                    if self.length > TABLE_LOOKUP_LENGTH_MAX || offset > TABLE_LOOKUP_DISTANCE_MAX {
+                        return Err(InternalErr::DataError);
+                    }
+
                     self.output.write_length_distance(self.length, offset);
                     free_bytes -= self.length;
                     self.state = InflaterState::DecodeTop;

tests/issue-25.rs

@@ -0,0 +1,25 @@
+use deflate64::InflaterManaged;
+
+static ZIP_FILE_DATA: &[u8] =
+    include_bytes!("../test-assets/issue-25/deflate64_not_enough_space.zip");
+
+fn deflate64_data() -> &'static [u8] {
+    &ZIP_FILE_DATA[30..]
+}
+
+// panic with invalid deflate64 data (too big lookup length)
+
+#[test]
+fn issue_25() {
+    let compressed_data = deflate64_data();
+
+    let mut inflater = Box::new(InflaterManaged::new());
+    let mut sink = vec![0u8; 1024 * 1024 * 4];
+
+    let output = inflater.inflate(compressed_data, &mut sink);
+
+    assert!(
+        output.data_error,
+        "expected an error since this deflate64 file is invalid"
+    );
+}