From d69d3c4aad5fb14160ec40fc01980bd1be5986a1 Mon Sep 17 00:00:00 2001
From: Steven Fackler <sfackler@gmail.com>
Date: Mon, 1 Jun 2015 20:54:34 -0700
Subject: [PATCH] Fix overflow check

---
 src/message.rs | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/message.rs b/src/message.rs
index 68aca5de..aa47f621 100644
--- a/src/message.rs
+++ b/src/message.rs
@@ -246,7 +246,10 @@ impl<W: Write> WriteMessage for W {
         }
 
         // add size of length value
-        try!(self.write_u32::<BigEndian>(try!(u32::from_usize(buf.len() + mem::size_of::<u32>()))));
+        if buf.len() > u32::max_value() as usize - mem::size_of::<u32>() {
+            return Err(io::Error::new(io::ErrorKind::InvalidInput, "value too large to transmit"));
+        }
+        try!(self.write_u32::<BigEndian>((buf.len() + mem::size_of::<u32>()) as u32));
         try!(self.write_all(&*buf));
 
         Ok(())