From f93b959b4a921c94f8659018184cb8061db15b47 Mon Sep 17 00:00:00 2001
From: Andrew Poelstra <apoelstra@wpsoftware.net>
Date: Wed, 15 Aug 2018 17:05:17 +0000
Subject: [PATCH] disallow Messages that are not valid secret keys to prevent
 mistakes related to 0

---
 src/lib.rs | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/src/lib.rs b/src/lib.rs
index 81cbc57..b75993f 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -504,6 +504,10 @@ impl Message {
     /// Converts a `MESSAGE_SIZE`-byte slice to a message object
     #[inline]
     pub fn from_slice(data: &[u8]) -> Result<Message, Error> {
+        if data == &[0; constants::MESSAGE_SIZE] {
+            return Err(Error::InvalidMessage);
+        }
+
         match data.len() {
             constants::MESSAGE_SIZE => {
                 let mut ret = [0; constants::MESSAGE_SIZE];
@@ -515,13 +519,6 @@ impl Message {
     }
 }
 
-/// Creates a message from a `MESSAGE_SIZE` byte array
-impl From<[u8; constants::MESSAGE_SIZE]> for Message {
-    fn from(buf: [u8; constants::MESSAGE_SIZE]) -> Message {
-        Message(buf)
-    }
-}
-
 /// An ECDSA error
 #[derive(Copy, PartialEq, Eq, Clone, Debug)]
 pub enum Error {
@@ -990,17 +987,16 @@ mod tests {
         s.randomize(&mut thread_rng());
 
         // Wild keys: 1, CURVE_ORDER - 1
-        // Wild msgs: 0, 1, CURVE_ORDER - 1, CURVE_ORDER
+        // Wild msgs: 1, CURVE_ORDER - 1
         let mut wild_keys = [[0; 32]; 2];
-        let mut wild_msgs = [[0; 32]; 4];
+        let mut wild_msgs = [[0; 32]; 2];
 
         wild_keys[0][0] = 1;
-        wild_msgs[1][0] = 1;
+        wild_msgs[0][0] = 1;
 
         use constants;
         wild_keys[1][..].copy_from_slice(&constants::CURVE_ORDER[..]);
         wild_msgs[1][..].copy_from_slice(&constants::CURVE_ORDER[..]);
-        wild_msgs[2][..].copy_from_slice(&constants::CURVE_ORDER[..]);
 
         wild_keys[1][0] -= 1;
         wild_msgs[1][0] -= 1;
@@ -1079,7 +1075,11 @@ mod tests {
                    Err(InvalidMessage));
         assert_eq!(Message::from_slice(&[0; constants::MESSAGE_SIZE + 1]),
                    Err(InvalidMessage));
-        assert!(Message::from_slice(&[0; constants::MESSAGE_SIZE]).is_ok());
+        assert_eq!(
+            Message::from_slice(&[0; constants::MESSAGE_SIZE]),
+            Err(InvalidMessage)
+        );
+        assert!(Message::from_slice(&[1; constants::MESSAGE_SIZE]).is_ok());
     }
 
     #[test]