verify lump size before reading

src/error.rs

@@ -9,6 +9,11 @@ pub enum BspError {
     UnexpectedHeader(Header),
     #[error("bsp lump is out of bounds of the bsp file")]
     LumpOutOfBounds(LumpEntry),
+    #[error("Invalid lump size, lump size {lump_size} is not a multiple of the element size {element_size}")]
+    InvalidLumpSize {
+        element_size: usize,
+        lump_size: usize,
+    },
     #[error("unexpected length of uncompressed lump, got {got} but expected {expected}")]
     UnexpectedUncompressedLumpSize { got: u32, expected: u32 },
     #[error("error while decompressing lump")]

src/reader.rs

@@ -31,6 +31,12 @@ impl<R: BinReaderExt + Read> LumpReader<R> {
     where
         F: FnMut(&mut LumpReader<R>) -> BspResult<T>,
     {
+        if self.length % size_of::<T>() != 0 {
+            return Err(BspError::InvalidLumpSize {
+                element_size: size_of::<T>(),
+                lump_size: self.length,
+            });
+        }
         let num_entries = self.length / size_of::<T>();
         let mut entries = Vec::with_capacity(num_entries);