openpgp: Implement conversion from const size arrays for Protected.

  - This type of array is used by ed25519-dalek crate.

1 files changed, 12 insertions, 0 deletions

diff --git a/openpgp/src/crypto/mem.rs b/openpgp/src/crypto/mem.rs
index dd63dfbd..c795c7e1 100644
--- a/openpgp/src/crypto/mem.rs
+++ b/openpgp/src/crypto/mem.rs
@@ -170,6 +170,18 @@ impl From<&[u8]> for Protected {
     }
 }
 
+impl<const N: usize> From<[u8; N]> for Protected {
+    fn from(v: [u8; N]) -> Self {
+        let mut p = Protected::new(v.len());
+
+        // Very carefully copy the slice.  The obvious
+        // `p.copy_from_slice(v);` indeed leaks secrets.
+        v.iter().zip(p.iter_mut()).for_each(|(f, t)| *t = *f);
+
+        p
+    }
+}
+
 impl Drop for Protected {
     fn drop(&mut self) {
         unsafe {