Clean up clippy warnings

Author: stouset

sample/bin/sudo_approve

@@ -50,6 +50,10 @@ pair() {
     # (which causes a SIGPIPE to get sent). So the `kill` ensures the
     # subshell is killed without the user having to type something
     # additional that would cause the command to exit.
+    #
+    # FIXME: Technically, `echo` puts a secret value into an process
+    # argument list, which isn't great. However, the window for
+    # exploitation here is microscopic.
     { socat STDIO unix-connect:"${socket}"; kill $!; } < <(
         echo -n "${token}" ; cat -
     )

sudo_pair/src/lib.rs

@@ -282,7 +282,13 @@ impl SudoPair {
         ).context(ErrorKind::CommunicationError)?;
 
         let mut response : [u8; 16] = [0; 16];
-        let _ = socket.read_exact(&mut response)
+
+        // TODO: read_exact will cause this process to block
+        // indefinitely (even on Ctrl-C) until the correct number of
+        // bytes are read; this won't happen in normal circumstances,
+        // but a bug in (or untimely exit of) the approval script can
+        // cause this process to hang and require being killed
+        socket.read_exact(&mut response)
             .context(ErrorKind::CommunicationError)?;
 
         // non-constant comparison is fine here since a comparison