From d9cabcb74518cf025de2bbc4b5d23ee94c3bc74b Mon Sep 17 00:00:00 2001
From: lulu <pengfei.lulu@gmail.com>
Date: Thu, 11 May 2023 10:45:22 +0800
Subject: [PATCH] fix(legacy): fix cardano derive when session is reused (#393)

---
 legacy/firmware/config.c         |  9 ++++++++-
 legacy/firmware/fsm_msg_common.h | 18 +++++++++++++-----
 2 files changed, 21 insertions(+), 6 deletions(-)

diff --git a/legacy/firmware/config.c b/legacy/firmware/config.c
index 8e6e1085fb..1d59e27630 100644
--- a/legacy/firmware/config.c
+++ b/legacy/firmware/config.c
@@ -1770,6 +1770,13 @@ bool config_getTrezorCompMode(bool *trezor_comp_mode) {
   return sectrue == config_get_bool(KEY_TREZOR_COMP_MODE, trezor_comp_mode);
 }
 
-bool config_getDeriveCardano(void) { return derive_cardano; }
+bool config_getDeriveCardano(void) {
+  if ((activeSessionCache->cardanoSecretCached != sectrue) &&
+      (activeSessionCache->seedCached == sectrue)) {
+    return false;  // only BIP-0039
+  }
+
+  return true;
+}
 
 void config_setDeriveCardano(bool on) { derive_cardano = on; }
diff --git a/legacy/firmware/fsm_msg_common.h b/legacy/firmware/fsm_msg_common.h
index a419b55dc3..a7ac913144 100644
--- a/legacy/firmware/fsm_msg_common.h
+++ b/legacy/firmware/fsm_msg_common.h
@@ -209,11 +209,6 @@ bool get_features(Features *resp) {
 
 void fsm_msgInitialize(const Initialize *msg) {
   fsm_abortWorkflows();
-  if (msg && msg->has_derive_cardano && msg->derive_cardano) {
-    config_setDeriveCardano(true);
-  } else {
-    config_setDeriveCardano(false);
-  }
 
   uint8_t *session_id;
   if (msg && msg->has_session_id) {
@@ -222,6 +217,19 @@ void fsm_msgInitialize(const Initialize *msg) {
     session_id = session_startSession(NULL);
   }
 
+  if (msg && msg->has_derive_cardano && msg->derive_cardano) {
+    if (!config_getDeriveCardano()) {
+      // seed is already derived, and host wants to change derive_cardano
+      // setting
+      // => create a new session
+      session_endCurrentSession();
+      session_id = session_startSession(NULL);
+    }
+    config_setDeriveCardano(true);
+  } else {
+    config_setDeriveCardano(false);
+  }
+
   RESP_INIT(Features);
   get_features(resp);