From 03d55f3ebdb3a78961861a197acfd88a7b123dc5 Mon Sep 17 00:00:00 2001
From: shimun <shimun@shimun.net>
Date: Mon, 13 Apr 2020 20:01:09 +0200
Subject: [PATCH] init shared_secret on demand

---
 src/extensions/hmac.rs | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/extensions/hmac.rs b/src/extensions/hmac.rs
index 45e3b60..83ef7aa 100644
--- a/src/extensions/hmac.rs
+++ b/src/extensions/hmac.rs
@@ -156,7 +156,12 @@ impl HmacSecret {
         salt: &[u8; 32],
         salt2: Option<&[u8; 32]>,
     ) -> FidoResult<Value> {
-        let shared_secret = device.shared_secret.as_ref().unwrap();
+        let shared_secret = loop {
+            if let Some(ref secret) = device.shared_secret {
+                break secret;
+            }
+            device.init_shared_secret()?;
+        };
         let mut encryptor = shared_secret.encryptor();
         let mut salt_enc = [0u8; 64];
         let mut output = RefWriteBuffer::new(&mut salt_enc);