wallet: wipe seed from memory where appropriate

1 files changed, 31 insertions, 13 deletions

diff --git a/src/wallet/wallet2.cpp b/src/wallet/wallet2.cpp
index 9deaad09b..e61e437c0 100644
--- a/src/wallet/wallet2.cpp
+++ b/src/wallet/wallet2.cpp
@@ -789,7 +789,7 @@ bool wallet2::is_deterministic() const
   return keys_deterministic;
 }
 //----------------------------------------------------------------------------------------------------
-bool wallet2::get_seed(std::string& electrum_words, const epee::wipeable_string &passphrase) const
+bool wallet2::get_seed(epee::wipeable_string& electrum_words, const epee::wipeable_string &passphrase) const
 {
   bool keys_deterministic = is_deterministic();
   if (!keys_deterministic)
@@ -815,7 +815,7 @@ bool wallet2::get_seed(std::string& electrum_words, const epee::wipeable_string
   return true;
 }
 //----------------------------------------------------------------------------------------------------
-bool wallet2::get_multisig_seed(std::string& seed, const epee::wipeable_string &passphrase, bool raw) const
+bool wallet2::get_multisig_seed(epee::wipeable_string& seed, const epee::wipeable_string &passphrase, bool raw) const
 {
   bool ready;
   uint32_t threshold, total;
@@ -838,7 +838,7 @@ bool wallet2::get_multisig_seed(std::string& seed, const epee::wipeable_string &
   crypto::secret_key skey;
   crypto::public_key pkey;
   const account_keys &keys = get_account().get_keys();
-  std::string data;
+  epee::wipeable_string data;
   data.append((const char*)&threshold, sizeof(uint32_t));
   data.append((const char*)&total, sizeof(uint32_t));
   skey = keys.m_spend_secret_key;
@@ -864,7 +864,7 @@ bool wallet2::get_multisig_seed(std::string& seed, const epee::wipeable_string &
 
   if (raw)
   {
-    seed = epee::string_tools::buff_to_hex_nodelimer(data);
+    seed = epee::to_hex::wipeable_string({(const unsigned char*)data.data(), data.size()});
   }
   else
   {
@@ -3161,7 +3161,7 @@ bool wallet2::verify_password(const std::string& keys_file_name, const epee::wip
  * \param  create_address_file  Whether to create an address file
  */
 void wallet2::generate(const std::string& wallet_, const epee::wipeable_string& password,
-  const std::string& multisig_data, bool create_address_file)
+  const epee::wipeable_string& multisig_data, bool create_address_file)
 {
   clear();
   prepare_file_names(wallet_);
@@ -10671,14 +10671,14 @@ size_t wallet2::import_multisig(std::vector<cryptonote::blobdata> blobs)
   return n_outputs;
 }
 //----------------------------------------------------------------------------------------------------
-std::string wallet2::encrypt(const std::string &plaintext, const crypto::secret_key &skey, bool authenticated) const
+std::string wallet2::encrypt(const char *plaintext, size_t len, const crypto::secret_key &skey, bool authenticated) const
 {
   crypto::chacha_key key;
   crypto::generate_chacha_key(&skey, sizeof(skey), key, m_kdf_rounds);
   std::string ciphertext;
   crypto::chacha_iv iv = crypto::rand<crypto::chacha_iv>();
-  ciphertext.resize(plaintext.size() + sizeof(iv) + (authenticated ? sizeof(crypto::signature) : 0));
-  crypto::chacha20(plaintext.data(), plaintext.size(), key, iv, &ciphertext[sizeof(iv)]);
+  ciphertext.resize(len + sizeof(iv) + (authenticated ? sizeof(crypto::signature) : 0));
+  crypto::chacha20(plaintext, len, key, iv, &ciphertext[sizeof(iv)]);
   memcpy(&ciphertext[0], &iv, sizeof(iv));
   if (authenticated)
   {
@@ -10692,12 +10692,28 @@ std::string wallet2::encrypt(const std::string &plaintext, const crypto::secret_
   return ciphertext;
 }
 //----------------------------------------------------------------------------------------------------
+std::string wallet2::encrypt(const epee::span<char> &plaintext, const crypto::secret_key &skey, bool authenticated) const
+{
+  return encrypt(plaintext.data(), plaintext.size(), skey, authenticated);
+}
+//----------------------------------------------------------------------------------------------------
+std::string wallet2::encrypt(const std::string &plaintext, const crypto::secret_key &skey, bool authenticated) const
+{
+  return encrypt(plaintext.data(), plaintext.size(), skey, authenticated);
+}
+//----------------------------------------------------------------------------------------------------
+std::string wallet2::encrypt(const epee::wipeable_string &plaintext, const crypto::secret_key &skey, bool authenticated) const
+{
+  return encrypt(plaintext.data(), plaintext.size(), skey, authenticated);
+}
+//----------------------------------------------------------------------------------------------------
 std::string wallet2::encrypt_with_view_secret_key(const std::string &plaintext, bool authenticated) const
 {
   return encrypt(plaintext, get_account().get_keys().m_view_secret_key, authenticated);
 }
 //----------------------------------------------------------------------------------------------------
-std::string wallet2::decrypt(const std::string &ciphertext, const crypto::secret_key &skey, bool authenticated) const
+template<typename T>
+T wallet2::decrypt(const std::string &ciphertext, const crypto::secret_key &skey, bool authenticated) const
 {
   const size_t prefix_size = sizeof(chacha_iv) + (authenticated ? sizeof(crypto::signature) : 0);
   THROW_WALLET_EXCEPTION_IF(ciphertext.size() < prefix_size,
@@ -10706,8 +10722,6 @@ std::string wallet2::decrypt(const std::string &ciphertext, const crypto::secret
   crypto::chacha_key key;
   crypto::generate_chacha_key(&skey, sizeof(skey), key, m_kdf_rounds);
   const crypto::chacha_iv &iv = *(const crypto::chacha_iv*)&ciphertext[0];
-  std::string plaintext;
-  plaintext.resize(ciphertext.size() - prefix_size);
   if (authenticated)
   {
     crypto::hash hash;
@@ -10718,10 +10732,14 @@ std::string wallet2::decrypt(const std::string &ciphertext, const crypto::secret
     THROW_WALLET_EXCEPTION_IF(!crypto::check_signature(hash, pkey, signature),
       error::wallet_internal_error, "Failed to authenticate ciphertext");
   }
-  crypto::chacha20(ciphertext.data() + sizeof(iv), ciphertext.size() - prefix_size, key, iv, &plaintext[0]);
-  return plaintext;
+  std::unique_ptr<char[]> buffer{new char[ciphertext.size() - prefix_size]};
+  auto wiper = epee::misc_utils::create_scope_leave_handler([&]() { memwipe(buffer.get(), ciphertext.size() - prefix_size); });
+  crypto::chacha20(ciphertext.data() + sizeof(iv), ciphertext.size() - prefix_size, key, iv, buffer.get());
+  return T(buffer.get(), ciphertext.size() - prefix_size);
 }
 //----------------------------------------------------------------------------------------------------
+template epee::wipeable_string wallet2::decrypt(const std::string &ciphertext, const crypto::secret_key &skey, bool authenticated) const;
+//----------------------------------------------------------------------------------------------------
 std::string wallet2::decrypt_with_view_secret_key(const std::string &ciphertext, bool authenticated) const
 {
   return decrypt(ciphertext, get_account().get_keys().m_view_secret_key, authenticated);