From 08b7fe4e92c7706fbc6a107e8bc7cf96d66e3bd5 Mon Sep 17 00:00:00 2001
From: b4n6-b4n6 <b4n6-b4n6@☯.com>
Date: Fri, 30 Aug 2024 20:40:01 +0700
Subject: [PATCH] Implement ElectrumWords::get_invalid_word

---
 src/mnemonics/electrum-words.cpp | 53 ++++++++++++++++++++++++++++++++
 src/mnemonics/electrum-words.h   |  2 ++
 src/wallet/api/wallet.cpp        |  7 ++++-
 tests/unit_tests/mnemonics.cpp   | 51 ++++++++++++++++++++++++++++++
 4 files changed, 112 insertions(+), 1 deletion(-)

diff --git a/src/mnemonics/electrum-words.cpp b/src/mnemonics/electrum-words.cpp
index 171dd750c8..3e4d4d5dcf 100644
--- a/src/mnemonics/electrum-words.cpp
+++ b/src/mnemonics/electrum-words.cpp
@@ -371,6 +371,59 @@ namespace crypto
       return true;
     }
 
+    std::string get_invalid_word(const epee::wipeable_string &words)
+    {
+      // If there's a new language added, add an instance of it here.
+      std::vector<Language::Base*> language_instances({
+        Language::Singleton<Language::Chinese_Simplified>::instance(),
+        Language::Singleton<Language::English>::instance(),
+        Language::Singleton<Language::Dutch>::instance(),
+        Language::Singleton<Language::French>::instance(),
+        Language::Singleton<Language::Spanish>::instance(),
+        Language::Singleton<Language::German>::instance(),
+        Language::Singleton<Language::Italian>::instance(),
+        Language::Singleton<Language::Portuguese>::instance(),
+        Language::Singleton<Language::Japanese>::instance(),
+        Language::Singleton<Language::Russian>::instance(),
+        Language::Singleton<Language::Esperanto>::instance(),
+        Language::Singleton<Language::Lojban>::instance(),
+        Language::Singleton<Language::EnglishOld>::instance()
+      });
+
+      std::vector<epee::wipeable_string> seed;
+      words.split(seed);
+
+      for (
+        std::vector<epee::wipeable_string>::const_iterator seed_i = seed.begin();
+        seed_i != seed.end();
+        seed_i++
+      )
+      {
+        bool has_any = false;
+
+        for (
+          std::vector<Language::Base*>::iterator lang_i = language_instances.begin();
+          lang_i != language_instances.end() && !has_any;
+          lang_i++
+        )
+        {
+          auto &word_map = (*lang_i)->get_word_map();
+
+          if (word_map.count(*seed_i) != 0)
+          {
+            has_any = true;
+            break;
+          }
+        }
+
+        if (!has_any) {
+          return std::string(seed_i->data(), seed_i->size());
+        }
+      }
+
+      return "";
+    }
+
     /*!
      * \brief Converts bytes (secret key) to seed words.
      * \param  src           Secret key
diff --git a/src/mnemonics/electrum-words.h b/src/mnemonics/electrum-words.h
index 374ebef57e..8231ffe5d5 100644
--- a/src/mnemonics/electrum-words.h
+++ b/src/mnemonics/electrum-words.h
@@ -83,6 +83,8 @@ namespace crypto
     bool words_to_bytes(const epee::wipeable_string &words, crypto::secret_key& dst,
       std::string &language_name);
 
+    std::string get_invalid_word(const epee::wipeable_string &words);
+
     /*!
      * \brief Converts bytes to seed words.
      * \param  src           Secret data
diff --git a/src/wallet/api/wallet.cpp b/src/wallet/api/wallet.cpp
index c8257919dd..13c703b4b8 100644
--- a/src/wallet/api/wallet.cpp
+++ b/src/wallet/api/wallet.cpp
@@ -749,7 +749,12 @@ bool WalletImpl::recover(const std::string &path, const std::string &password, c
     crypto::secret_key recovery_key;
     std::string old_language;
     if (!crypto::ElectrumWords::words_to_bytes(seed, recovery_key, old_language)) {
-        setStatusError(tr("Electrum-style word list failed verification"));
+        std::string invalid_word = crypto::ElectrumWords::get_invalid_word(seed);
+        if (invalid_word != "") {
+            setStatusError((boost::format(tr("Invalid word %s")) % ("'" + invalid_word + "'")).str());
+        } else {
+            setStatusError(tr("Electrum-style word list failed verification"));
+        }
         return false;
     }
     if (!seed_offset.empty())
diff --git a/tests/unit_tests/mnemonics.cpp b/tests/unit_tests/mnemonics.cpp
index 8e8886f551..60e67cae43 100644
--- a/tests/unit_tests/mnemonics.cpp
+++ b/tests/unit_tests/mnemonics.cpp
@@ -255,3 +255,54 @@ TEST(mnemonics, partial_word_tolerance)
     ASSERT_EQ(true, res);
     ASSERT_STREQ(language_name_1.c_str(), "English");
 }
+
+TEST(mnemonics, get_invalid_word)
+{
+    ASSERT_TRUE(
+      crypto::ElectrumWords::get_invalid_word(
+        "crim bam scamp gna limi woma wron tuit birth mundane donuts square cohesive dolphin titans narrate fue saved wrap aloof magic mirr toget upda wra"
+      ) == "crim"
+    );
+
+    ASSERT_TRUE(
+      crypto::ElectrumWords::get_invalid_word(
+        "criminal bamboo scamper gnaw limits womanly wrong tuition birth mundane donuts square cohesive dolphin titans narrate fue saved wrap aloof magically mirror together update wrap"
+      ) == "fue"
+    );
+
+    ASSERT_TRUE(
+      crypto::ElectrumWords::get_invalid_word(
+        "a a a a a a a a a a a a a a a a a a a a a a a a a"
+      ) == "a"
+    );
+
+    ASSERT_TRUE(
+      crypto::ElectrumWords::get_invalid_word(
+        "abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandonnn abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon"
+      ) == "abandonnn"
+    );
+  
+    ASSERT_TRUE(
+      crypto::ElectrumWords::get_invalid_word(
+        "abando abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandonnn abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon"
+      ) == "abando"
+    );
+  
+    ASSERT_TRUE(
+      crypto::ElectrumWords::get_invalid_word(
+        "criminal bamboo scamper gnaw limits womanly wrong tuition birth mundane donuts square cohesive dolphin titans narrate fuel saved wrap aloof magically mirror together update wrap"
+      ) == ""
+    );
+
+    ASSERT_TRUE(
+      crypto::ElectrumWords::get_invalid_word(
+        "abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon"
+      ) == ""
+    );
+
+    ASSERT_TRUE(
+      crypto::ElectrumWords::get_invalid_word(
+        "ㇴ"
+      ) == "ㇴ"
+    );
+}