diff --git a/src/windows.rs b/src/windows.rs
index cc7f423..83e4b48 100644
--- a/src/windows.rs
+++ b/src/windows.rs
@@ -26,6 +26,7 @@ use self::winapi::um::winnt::*;
 use self::winapi::um::winver::*;
 use super::Uname;
 use std::borrow::Cow;
+use std::convert::TryFrom;
 use std::ffi::{CStr, OsStr, OsString};
 use std::io;
 use std::iter;
@@ -105,7 +106,9 @@ impl PlatformInfo {
         let mut data: Vec<u16> = vec![0; size as usize];
         unsafe {
             if GetComputerNameExW(ComputerNameDnsHostname, data.as_mut_ptr(), &mut size) != 0 {
-                Ok(String::from_utf16_lossy(&data))
+                Ok(String::from_utf16_lossy(
+                    &data[..usize::try_from(size).unwrap()],
+                ))
             } else {
                 // XXX: should this error or just return localhost?
                 Err(io::Error::last_os_error())