Wordlist validator on keychain backup wizard.

Author: CodeShark

src/keychainbackupwizard.cpp

@@ -27,7 +27,7 @@ KeychainBackupWizard::KeychainBackupWizard(const QString& name, const secure_byt
 {
     addPage(new WordlistViewPage(name, seed));
     addPage(new WordlistVerifyPage(name, seed));
-    addPage(new WordlistCompletePage());
+    addPage(new WordlistCompletePage(name));
     setWindowTitle(tr("Keychain Backup"));
 }
 
@@ -36,6 +36,7 @@ WordlistViewPage::WordlistViewPage(const QString& name, const secure_bytes_t& se
     : QWizardPage(parent)
 {
     setTitle(tr("Step 1: Copy"));
+    setSubTitle(tr("Keychain: ") + name);
 
     QLabel* promptLabel = new QLabel(tr("IMPORTANT: Please write down the following list of words. In the event you lose your data you can recover your keychain by entering this list."));
     promptLabel->setWordWrap(true);
@@ -53,22 +54,24 @@ WordlistViewPage::WordlistViewPage(const QString& name, const secure_bytes_t& se
 WordlistVerifyPage::WordlistVerifyPage(const QString& name, const secure_bytes_t& seed, QWidget* parent)
     : QWizardPage(parent)
 {
-    setTitle(tr("Step 2: Verify"));
+    using namespace Coin;
 
-    wordlist = Coin::BIP39::toWordlist(seed).c_str();
+    setTitle(tr("Step 2: Verify"));
+    setSubTitle(tr("Keychain: ") + name);
 
     QLabel* promptLabel = new QLabel(tr("Please enter the words in the correct order below:"));
     promptLabel->setWordWrap(true);
 
+    wordlist = BIP39::toWordlist(seed).c_str();
+
     wordlistEdit = new QLineEdit();
-    wordlistEdit->setValidator(new WordlistValidator(this));
+    wordlistEdit->setValidator(new WordlistValidator(BIP39::minWordLen(), BIP39::maxWordLen(), this));
+    QObject::connect(wordlistEdit, &QLineEdit::textChanged, [=]() { emit completeChanged(); });
 
     QVBoxLayout* layout = new QVBoxLayout();
     layout->addWidget(promptLabel);
     layout->addWidget(wordlistEdit);
     setLayout(layout);
-
-    QObject::connect(wordlistEdit, &QLineEdit::textChanged, [=]() { emit completeChanged(); });
 }
 
 /*
@@ -84,10 +87,11 @@ bool WordlistVerifyPage::isComplete() const
     return (wordlist == wordlistEdit->text());
 }
 
-WordlistCompletePage::WordlistCompletePage(QWidget* parent)
+WordlistCompletePage::WordlistCompletePage(const QString& name, QWidget* parent)
     : QWizardPage(parent)
 {
     setTitle(tr("Step 3: Put in safe, secure place"));
+    setSubTitle(tr("Keychain: ") + name);
 
     QLabel* promptLabel = new QLabel(tr("IMPORTANT: Keep the wordlist in a safe place."));
     promptLabel->setWordWrap(true);

src/keychainbackupwizard.h

@@ -58,5 +58,5 @@ class WordlistCompletePage : public QWizardPage
     Q_OBJECT
 
 public:
-    WordlistCompletePage(QWidget* parent = NULL);
+    WordlistCompletePage(const QString& name, QWidget* parent = NULL);
 };

src/wordlistvalidator.cpp

@@ -10,19 +10,81 @@
 
 #include "wordlistvalidator.h"
 
-WordlistValidator::WordlistValidator(QObject* parent) :
-    QValidator(parent)
-{
-}
+#include <string>
 
-void WordlistValidator::fixup(QString& input) const
+WordlistValidator::WordlistValidator(int minlen, int maxlen, QObject* parent) :
+    QValidator(parent), minlen_(minlen), maxlen_(maxlen)
 {
-    input = input.toLower();
 }
 
-QValidator::State WordlistValidator::validate(QString& input, int& /*pos*/) const
+QValidator::State WordlistValidator::validate(QString& input, int& pos) const
 {
     if (input.isEmpty()) return Intermediate;
-    return Acceptable; 
+    input = input.toLower();
+
+    // Backspace over spaces if we're not at the end.
+    if ((pos < input.size()) && (input.size() + 1 == lastInput.size()) && (lastInput[pos] == ' '))
+    {
+        QString temp = input.left(pos) + ' ' + input.right(input.size() - pos);
+        if (temp == lastInput) input = lastInput;
+    }
+
+    QString newInput;
+    int newPos = pos;
+    
+    std::string wordlist = input.toStdString();
+    int len = wordlist.size();
+
+    bool removeSpaces = true;
+    bool final = true;
+    QString lastWord;
+    int i = 0;
+    for (auto c: wordlist)
+    {
+        i++;
+        if (c == ' ')
+        {
+            if (lastWord.isEmpty())
+            {
+                // Strip extra spaces
+                if (newPos > newInput.size()) newPos--;
+            }
+            else if (lastWord.size() >= minlen_)
+            {
+                newInput += lastWord + ' ';
+                lastWord.clear();
+            }
+            else if (i < wordlist.size() && newPos > newInput.size())
+            {
+                // Remove words that are too short.
+                newPos = newInput.size() - 1;
+                lastWord.clear();
+            }
+            else
+            {
+                // Disallow adding a space that makes a word too short.
+                return Invalid;
+            }
+        }
+        else if (c >= 'a' && c <= 'z' && lastWord.size() < maxlen_)
+        {
+            lastWord += c;
+        }
+        else
+        {
+            return Invalid;
+        }
+    }
+
+    newInput += lastWord;
+
+    if (lastWord.size() < minlen_) final = false;
+
+    input = newInput;
+    pos = newPos;
+
+    lastInput = input;
+    
+    return final ? Acceptable : Intermediate;
 }
 

src/wordlistvalidator.h

@@ -18,8 +18,12 @@ class WordlistValidator : public QValidator
     Q_OBJECT
 
 public:
-    explicit WordlistValidator(QObject* parent = nullptr);
+    explicit WordlistValidator(int minlen, int maxlen, QObject* parent = nullptr);
     QValidator::State validate(QString& input, int& pos) const;
-    void fixup(QString& input) const;
+
+private:
+    mutable QString lastInput;
+    int minlen_;
+    int maxlen_;
 };