device: enable to use multiple independent device wallets

- adds a new option `--hw-device-deriv-path` to the simple wallet. Enables to specify wallet derivation path / wallet code (path avoided so it can be misinterpreted as a file path).
- devices can use different derivation mechanisms. Trezor uses standard SLIP-10 mechanism with fixed SLIP-44 prefix for Monero
- Trezor: when empty, the default derivation mechanism is used with 44'/128'/0'. When entered the derivation path is 44'/128'/PATH.
- Trezor: the path is always taken as elements are hardened (1<<31 bit turned on)

src/device_trezor/device_trezor_base.cpp

@@ -28,6 +28,9 @@
 //
 
 #include "device_trezor_base.hpp"
+#include <boost/algorithm/string/classification.hpp>
+#include <boost/algorithm/string/split.hpp>
+#include <boost/regex.hpp>
 
 namespace hw {
 namespace trezor {
@@ -36,8 +39,9 @@ namespace trezor {
 
 #undef MONERO_DEFAULT_LOG_CATEGORY
 #define MONERO_DEFAULT_LOG_CATEGORY "device.trezor"
+#define TREZOR_BIP44_HARDENED_ZERO 0x80000000
 
-    const uint32_t device_trezor_base::DEFAULT_BIP44_PATH[] = {0x8000002c, 0x80000080, 0x80000000};
+    const uint32_t device_trezor_base::DEFAULT_BIP44_PATH[] = {0x8000002c, 0x80000080};
 
     device_trezor_base::device_trezor_base(): m_callback(nullptr) {
 
@@ -252,6 +256,39 @@ namespace trezor {
       }
     }
 
+    void device_trezor_base::ensure_derivation_path() noexcept {
+      if (m_wallet_deriv_path.empty()){
+        m_wallet_deriv_path.push_back(TREZOR_BIP44_HARDENED_ZERO);  // default 0'
+      }
+    }
+
+    void device_trezor_base::set_derivation_path(const std::string &deriv_path){
+      this->m_wallet_deriv_path.clear();
+
+      if (deriv_path.empty() || deriv_path == "-"){
+        ensure_derivation_path();
+        return;
+      }
+
+      CHECK_AND_ASSERT_THROW_MES(deriv_path.size() <= 255, "Derivation path is too long");
+
+      std::vector<std::string> fields;
+      boost::split(fields, deriv_path, boost::is_any_of("/"));
+      CHECK_AND_ASSERT_THROW_MES(fields.size() <= 10, "Derivation path is too long");
+
+      boost::regex rgx("^([0-9]+)'?$");
+      boost::cmatch match;
+
+      this->m_wallet_deriv_path.reserve(fields.size());
+      for(const std::string & cur : fields){
+        const bool ok = boost::regex_match(cur.c_str(), match, rgx);
+        CHECK_AND_ASSERT_THROW_MES(ok, "Invalid wallet code: " << deriv_path << ". Invalid path element: " << cur);
+        CHECK_AND_ASSERT_THROW_MES(match[0].length() > 0, "Invalid wallet code: " << deriv_path << ". Invalid path element: " << cur);
+
+        const unsigned long cidx = std::stoul(match[0].str()) | TREZOR_BIP44_HARDENED_ZERO;
+        this->m_wallet_deriv_path.push_back((unsigned int)cidx);
+      }
+    }
 
     /* ======================================================================= */
     /*                              TREZOR PROTOCOL                            */

src/device_trezor/device_trezor_base.hpp

@@ -71,6 +71,7 @@ namespace trezor {
       i_device_callback * m_callback;
 
       std::string full_name;
+      std::vector<unsigned int> m_wallet_deriv_path;
 
       cryptonote::network_type network_type;
 
@@ -81,6 +82,7 @@ namespace trezor {
       void require_connected();
       void call_ping_unsafe();
       void test_ping();
+      void ensure_derivation_path() noexcept;
 
       // Communication methods
 
@@ -176,9 +178,13 @@ namespace trezor {
             msg->add_address_n(x);
           }
         } else {
+          ensure_derivation_path();
           for (unsigned int i : DEFAULT_BIP44_PATH) {
             msg->add_address_n(i);
           }
+          for (unsigned int i : m_wallet_deriv_path) {
+            msg->add_address_n(i);
+          }
         }
 
         if (network_type){
@@ -201,7 +207,7 @@ namespace trezor {
     bool reset();
 
     // Default derivation path for Monero
-    static const uint32_t DEFAULT_BIP44_PATH[3];
+    static const uint32_t DEFAULT_BIP44_PATH[2];
 
     std::shared_ptr<Transport> getTransport(){
       return m_transport;
@@ -215,6 +221,8 @@ namespace trezor {
       return m_callback;
     }
 
+    void set_derivation_path(const std::string &deriv_path) override;
+
     /* ======================================================================= */
     /*                              SETUP/TEARDOWN                             */
     /* ======================================================================= */