From 20c5b903dbd2ffc6031880e898be307e70e7bf9c Mon Sep 17 00:00:00 2001
From: Peter Todd <pete@petertodd.org>
Date: Mon, 8 May 2017 07:18:35 -0400
Subject: [PATCH] Replace unsafe copy_nonoverlapping() with safe
 copy_from_slice()

---
 src/key.rs     | 12 ++----------
 src/lib.rs     | 29 +++++++++--------------------
 src/schnorr.rs | 18 +++++-------------
 3 files changed, 16 insertions(+), 43 deletions(-)

diff --git a/src/key.rs b/src/key.rs
index a3d994b..c404dca 100644
--- a/src/key.rs
+++ b/src/key.rs
@@ -15,7 +15,6 @@
 
 //! # Public and secret keys
 
-use std::intrinsics::copy_nonoverlapping;
 use std::marker;
 use arrayvec::ArrayVec;
 use rand::Rng;
@@ -86,10 +85,8 @@ impl SecretKey {
                     if ffi::secp256k1_ec_seckey_verify(secp.ctx, data.as_ptr()) == 0 {
                         return Err(InvalidSecretKey);
                     }
-                    copy_nonoverlapping(data.as_ptr(),
-                                        ret.as_mut_ptr(),
-                                        data.len());
                 }
+                ret[..].copy_from_slice(data);
                 Ok(SecretKey(ret))
             }
             _ => Err(InvalidSecretKey)
@@ -565,12 +562,7 @@ mod test {
                     0xba, 0xae, 0xdc, 0xe6, 0xaf, 0x48, 0xa0, 0x3b,
                     0xbf, 0xd2, 0x5e, 0x8c, 0xd0, 0x36, 0x41, 0x41];
                 assert_eq!(data.len(), 32);
-                unsafe {
-                    use std::intrinsics::copy_nonoverlapping;
-                    copy_nonoverlapping(group_order.as_ptr(),
-                                        data.as_mut_ptr(),
-                                        32);
-                }
+                data.copy_from_slice(&group_order[..]);
                 data[31] = self.0;
                 self.0 -= 1;
             }
diff --git a/src/lib.rs b/src/lib.rs
index d878500..a81e1e9 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -290,11 +290,7 @@ impl Message {
         match data.len() {
             constants::MESSAGE_SIZE => {
                 let mut ret = [0; constants::MESSAGE_SIZE];
-                unsafe {
-                    ptr::copy_nonoverlapping(data.as_ptr(),
-                                             ret.as_mut_ptr(),
-                                             data.len());
-                }
+                ret[..].copy_from_slice(data);
                 Ok(Message(ret))
             }
             _ => Err(Error::InvalidMessage)
@@ -539,7 +535,6 @@ impl Secp256k1 {
 #[cfg(test)]
 mod tests {
     use rand::{Rng, thread_rng};
-    use std::ptr;
     use serialize::hex::FromHex;
 
     use key::{SecretKey, PublicKey};
@@ -712,20 +707,14 @@ mod tests {
 
         wild_keys[0][0] = 1;
         wild_msgs[1][0] = 1;
-        unsafe {
-            use constants;
-            ptr::copy_nonoverlapping(constants::CURVE_ORDER.as_ptr(),
-                                     wild_keys[1].as_mut_ptr(),
-                                     32);
-            ptr::copy_nonoverlapping(constants::CURVE_ORDER.as_ptr(),
-                                     wild_msgs[1].as_mut_ptr(),
-                                     32);
-            ptr::copy_nonoverlapping(constants::CURVE_ORDER.as_ptr(),
-                                     wild_msgs[2].as_mut_ptr(),
-                                     32);
-            wild_keys[1][0] -= 1;
-            wild_msgs[1][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;
 
         for key in wild_keys.iter().map(|k| SecretKey::from_slice(&s, &k[..]).unwrap()) {
             for msg in wild_msgs.iter().map(|m| Message::from_slice(&m[..]).unwrap()) {
diff --git a/src/schnorr.rs b/src/schnorr.rs
index 22fdeb8..d20cbbc 100644
--- a/src/schnorr.rs
+++ b/src/schnorr.rs
@@ -25,6 +25,7 @@ use ffi;
 use key::{SecretKey, PublicKey};
 
 use std::{mem, ptr};
+use std::convert::From;
 
 /// A Schnorr signature.
 pub struct Signature([u8; constants::SCHNORR_SIGNATURE_SIZE]);
@@ -35,23 +36,14 @@ impl Signature {
     /// Deserializes a signature from a 64-byte vector
     pub fn deserialize(data: &[u8]) -> Signature {
         assert_eq!(data.len(), constants::SCHNORR_SIGNATURE_SIZE);
-        unsafe {
-            let mut ret: Signature = mem::uninitialized();
-            ptr::copy_nonoverlapping(data.as_ptr(), ret.as_mut_ptr(),
-                                     constants::SCHNORR_SIGNATURE_SIZE);
-            ret
-        }
+        let mut ret = [0; constants::SCHNORR_SIGNATURE_SIZE];
+        ret[..].copy_from_slice(data);
+        Signature(ret)
     }
 
     /// Serializes a signature to a 64-byte vector
     pub fn serialize(&self) -> Vec<u8> {
-        let mut ret = Vec::with_capacity(constants::SCHNORR_SIGNATURE_SIZE);
-        unsafe {
-            ptr::copy_nonoverlapping(self.as_ptr(), ret.as_mut_ptr(),
-                                     constants::SCHNORR_SIGNATURE_SIZE);
-            ret.set_len(constants::SCHNORR_SIGNATURE_SIZE);
-        }
-        ret
+        Vec::from(&self.0[..])
     }
 }