[#64] Compatible if time is nagative

Author: zonyitoo

src/decoder/mod.rs

@@ -206,7 +206,11 @@ fn decode_bson<R: Read + ?Sized>(reader: &mut R, tag: u8, utf8_lossy: bool) -> D
             // The int64 is UTC milliseconds since the Unix epoch.
             let time = read_i64(reader)?;
 
-            match Utc.timestamp_opt(time / 1000, ((time % 1000) as u32) * 1_000_000) {
+            let sec = time / 1000;
+            let tmp_msec = time % 1000;
+            let msec = if tmp_msec < 0 { 1000 - tmp_msec } else { tmp_msec };
+
+            match Utc.timestamp_opt(sec, (msec as u32) * 1_000_000) {
                 LocalResult::None => Err(DecoderError::InvalidTimestamp(time)),
                 LocalResult::Ambiguous(..) => Err(DecoderError::AmbiguousTimestamp(time)),
                 LocalResult::Single(t) => Ok(Bson::UtcDatetime(t)),

tests/modules/encoder_decoder.rs

@@ -296,3 +296,17 @@ fn test_decode_utc_date_time_overflows() {
     let expected = doc! { "A" => Utc.timestamp(1530492218, 999 * 1_000_000)};
     assert_eq!(decoded, expected);
 }
+
+#[test]
+fn test_decode_invalid_utf8_string_issue64() {
+    let buffer = b"\x13\x00\x00\x00\x02\x01\x00\x00\x00\x00\x00\x00\x00foo\x00\x13\x05\x00\x00\x00";
+
+    assert!(decode_document(&mut Cursor::new(buffer)).is_err());
+}
+
+#[test]
+fn test_decode_multiply_overflows_issue64() {
+    let buffer = b"*\xc9*\xc9\t\x00\x00\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\xca\x01\t\x00\x00\x01\x10";
+
+    assert!(decode_document(&mut Cursor::new(&buffer[..])).is_err());
+}