new wipeable_string class to replace std::string passphrases

9 files changed, 64 insertions, 63 deletions

diff --git a/src/common/password.cpp b/src/common/password.cpp
index 01eaf62e1..98a49eb80 100644
--- a/src/common/password.cpp
+++ b/src/common/password.cpp
@@ -56,7 +56,7 @@ namespace
     return 0 != _isatty(_fileno(stdin));
   }
 
-  bool read_from_tty(std::string& pass)
+  bool read_from_tty(epee::wipeable_string& pass)
   {
     static constexpr const char BACKSPACE = 8;
 
@@ -88,8 +88,7 @@ namespace
       {
         if (!pass.empty())
         {
-          pass.back() = '\0';
-          pass.resize(pass.size() - 1);
+          pass.pop_back();
         }
       }
       else
@@ -127,7 +126,7 @@ namespace
     return ch;
   }
 
-  bool read_from_tty(std::string& aPass)
+  bool read_from_tty(epee::wipeable_string& aPass)
   {
     static constexpr const char BACKSPACE = 127;
 
@@ -148,8 +147,7 @@ namespace
       {
         if (!aPass.empty())
         {
-          aPass.back() = '\0';
-          aPass.resize(aPass.size() - 1);
+          aPass.pop_back();
         }
       }
       else
@@ -163,15 +161,7 @@ namespace
 
 #endif // end !WIN32
 
-  void clear(std::string& pass) noexcept
-  {
-    // technically, the std::string documentation says the data should not be modified,
-    // but there seems to be no way to get a non const raw pointer to the data
-    memwipe((void*)pass.data(), pass.size());
-    pass.clear();
-  }
-
-  bool read_from_tty(const bool verify, const char *message, std::string& pass1, std::string& pass2)
+  bool read_from_tty(const bool verify, const char *message, epee::wipeable_string& pass1, epee::wipeable_string& pass2)
   {
     while (true)
     {
@@ -187,8 +177,8 @@ namespace
         if(pass1!=pass2)
         {
           std::cout << "Passwords do not match! Please try again." << std::endl;
-          clear(pass1);
-          clear(pass2);
+          pass1.clear();
+          pass2.clear();
         }
         else //new password matches
           return true;
@@ -201,7 +191,7 @@ namespace
     return false;
   }
 
-  bool read_from_file(std::string& pass)
+  bool read_from_file(epee::wipeable_string& pass)
   {
     pass.reserve(tools::password_container::max_password_size);
     for (size_t i = 0; i < tools::password_container::max_password_size; ++i)
@@ -236,7 +226,7 @@ namespace tools
 
   password_container::~password_container() noexcept
   {
-    clear(m_password);
+    m_password.clear();
   }
 
   boost::optional<password_container> password_container::prompt(const bool verify, const char *message)
@@ -252,9 +242,8 @@ namespace tools
   boost::optional<login> login::parse(std::string&& userpass, bool verify, const std::function<boost::optional<password_container>(bool)> &prompt)
   {
     login out{};
-    password_container wipe{std::move(userpass)};
 
-    const auto loc = wipe.password().find(':');
+    const auto loc = userpass.find(':');
     if (loc == std::string::npos)
     {
       auto result = prompt(verify);
@@ -265,10 +254,11 @@ namespace tools
     }
     else
     {
-      out.password = password_container{wipe.password().substr(loc + 1)};
+      out.password = password_container{userpass.substr(loc + 1)};
     }
 
-    out.username = wipe.password().substr(0, loc);
+    out.username = userpass.substr(0, loc);
+    password_container wipe{std::move(userpass)};
     return {std::move(out)};
   }
 } 
diff --git a/src/common/password.h b/src/common/password.h
index ba1c30a28..01c6bf05a 100644
--- a/src/common/password.h
+++ b/src/common/password.h
@@ -32,6 +32,7 @@
 
 #include <string>
 #include <boost/optional/optional.hpp>
+#include "wipeable_string.h"
 
 namespace tools
 {
@@ -58,11 +59,10 @@ namespace tools
     password_container& operator=(const password_container&) = delete;
     password_container& operator=(password_container&&) = default;
 
-    const std::string& password() const noexcept { return m_password; }
+    const epee::wipeable_string &password() const noexcept { return m_password; }
 
   private:
-    //! TODO Custom allocator that locks to RAM?
-    std::string m_password;
+    epee::wipeable_string m_password;
   };
 
   struct login
diff --git a/src/common/util.cpp b/src/common/util.cpp
index 0d56e5eb7..eac5a67cf 100644
--- a/src/common/util.cpp
+++ b/src/common/util.cpp
@@ -36,9 +36,11 @@
 
 #include "include_base_utils.h"
 #include "file_io_utils.h"
+#include "wipeable_string.h"
 using namespace epee;
 
 #include "util.h"
+#include "memwipe.h"
 #include "cryptonote_config.h"
 #include "net/http_client.h"                        // epee::net_utils::...
 
@@ -542,6 +544,8 @@ std::string get_nix_version_display_string()
   }
   bool on_startup()
   {
+    wipeable_string::set_wipe(&memwipe);
+
     mlog_configure("", true);
 
     sanitize_locale();
diff --git a/src/cryptonote_basic/cryptonote_format_utils.cpp b/src/cryptonote_basic/cryptonote_format_utils.cpp
index 3c760493f..6759f1826 100644
--- a/src/cryptonote_basic/cryptonote_format_utils.cpp
+++ b/src/cryptonote_basic/cryptonote_format_utils.cpp
@@ -32,6 +32,7 @@
 using namespace epee;
 
 #include <atomic>
+#include "wipeable_string.h"
 #include "cryptonote_format_utils.h"
 #include "cryptonote_config.h"
 #include "crypto/crypto.h"
@@ -994,7 +995,7 @@ namespace cryptonote
     block_hashes_cached = block_hashes_cached_count;
   }
   //---------------------------------------------------------------
-  crypto::secret_key encrypt_key(crypto::secret_key key, const std::string &passphrase)
+  crypto::secret_key encrypt_key(crypto::secret_key key, const epee::wipeable_string &passphrase)
   {
     crypto::hash hash;
     crypto::cn_slow_hash(passphrase.data(), passphrase.size(), hash);
@@ -1002,7 +1003,7 @@ namespace cryptonote
     return key;
   }
   //---------------------------------------------------------------
-  crypto::secret_key decrypt_key(crypto::secret_key key, const std::string &passphrase)
+  crypto::secret_key decrypt_key(crypto::secret_key key, const epee::wipeable_string &passphrase)
   {
     crypto::hash hash;
     crypto::cn_slow_hash(passphrase.data(), passphrase.size(), hash);
diff --git a/src/cryptonote_basic/cryptonote_format_utils.h b/src/cryptonote_basic/cryptonote_format_utils.h
index aebeaa6f4..714d80195 100644
--- a/src/cryptonote_basic/cryptonote_format_utils.h
+++ b/src/cryptonote_basic/cryptonote_format_utils.h
@@ -38,6 +38,11 @@
 #include "crypto/hash.h"
 #include <unordered_map>
 
+namespace epee
+{
+  class wipeable_string;
+}
+
 namespace cryptonote
 {
   //---------------------------------------------------------------
@@ -226,8 +231,8 @@ namespace cryptonote
   bool is_valid_decomposed_amount(uint64_t amount);
   void get_hash_stats(uint64_t &tx_hashes_calculated, uint64_t &tx_hashes_cached, uint64_t &block_hashes_calculated, uint64_t & block_hashes_cached);
 
-  crypto::secret_key encrypt_key(crypto::secret_key key, const std::string &passphrase);
-  crypto::secret_key decrypt_key(crypto::secret_key key, const std::string &passphrase);
+  crypto::secret_key encrypt_key(crypto::secret_key key, const epee::wipeable_string &passphrase);
+  crypto::secret_key decrypt_key(crypto::secret_key key, const epee::wipeable_string &passphrase);
 #define CHECKED_GET_SPECIFIC_VARIANT(variant_var, specific_type, variable_name, fail_return_val) \
   CHECK_AND_ASSERT_MES(variant_var.type() == typeid(specific_type), fail_return_val, "wrong variant type: " << variant_var.type().name() << ", expected " << typeid(specific_type).name()); \
   specific_type& variable_name = boost::get<specific_type>(variant_var);
diff --git a/src/simplewallet/simplewallet.cpp b/src/simplewallet/simplewallet.cpp
index 17462bb81..a20bbd336 100644
--- a/src/simplewallet/simplewallet.cpp
+++ b/src/simplewallet/simplewallet.cpp
@@ -411,7 +411,7 @@ bool simple_wallet::print_seed(bool encrypted)
       m_wallet->set_seed_language(mnemonic_language);
     }
 
-    std::string seed_pass;
+    epee::wipeable_string seed_pass;
     if (encrypted)
     {
       auto pwd_container = tools::password_container::prompt(true, tr("Enter optional seed encryption passphrase, empty to see raw seed"));
@@ -1212,7 +1212,7 @@ bool simple_wallet::init(const boost::program_options::variables_map& vm)
       auto pwd_container = tools::password_container::prompt(false, tr("Enter seed encryption passphrase, empty if none"));
       if (std::cin.eof() || !pwd_container)
         return false;
-      std::string seed_pass = pwd_container->password();
+      epee::wipeable_string seed_pass = pwd_container->password();
       if (!seed_pass.empty())
         m_recovery_key = cryptonote::decrypt_key(m_recovery_key, seed_pass);
     }
@@ -1862,12 +1862,12 @@ bool simple_wallet::open_wallet(const boost::program_options::variables_map& vm)
     fail_msg_writer() << tr("wallet file path not valid: ") << m_wallet_file;
     return false;
   }
-  std::string password;
+  epee::wipeable_string password;
   try
   {
     auto rc = tools::wallet2::make_from_file(vm, m_wallet_file, password_prompter);
     m_wallet = std::move(rc.first);
-    password = std::move(rc.second).password();
+    password = std::move(std::move(rc.second).password());
     if (!m_wallet)
     {
       return false;
diff --git a/src/wallet/wallet2.cpp b/src/wallet/wallet2.cpp
index 3a8662890..13bf54212 100644
--- a/src/wallet/wallet2.cpp
+++ b/src/wallet/wallet2.cpp
@@ -602,7 +602,7 @@ bool wallet2::is_deterministic() const
   return keys_deterministic;
 }
 //----------------------------------------------------------------------------------------------------
-bool wallet2::get_seed(std::string& electrum_words, const std::string &passphrase) const
+bool wallet2::get_seed(std::string& electrum_words, const epee::wipeable_string &passphrase) const
 {
   bool keys_deterministic = is_deterministic();
   if (!keys_deterministic)
@@ -2128,7 +2128,7 @@ bool wallet2::clear()
  * \param  watch_only     true to save only view key, false to save both spend and view keys
  * \return                Whether it was successful.
  */
-bool wallet2::store_keys(const std::string& keys_file_name, const std::string& password, bool watch_only)
+bool wallet2::store_keys(const std::string& keys_file_name, const epee::wipeable_string& password, bool watch_only)
 {
   std::string account_data;
   cryptonote::account_base account = m_account;
@@ -2214,7 +2214,7 @@ bool wallet2::store_keys(const std::string& keys_file_name, const std::string& p
 
   // Encrypt the entire JSON object.
   crypto::chacha8_key key;
-  crypto::generate_chacha8_key(password, key);
+  crypto::generate_chacha8_key(password.data(), password.size(), key);
   std::string cipher;
   cipher.resize(account_data.size());
   keys_file_data.iv = crypto::rand<crypto::chacha8_iv>();
@@ -2244,7 +2244,7 @@ namespace
  * \param keys_file_name Name of wallet file
  * \param password       Password of wallet file
  */
-bool wallet2::load_keys(const std::string& keys_file_name, const std::string& password)
+bool wallet2::load_keys(const std::string& keys_file_name, const epee::wipeable_string& password)
 {
   wallet2::keys_file_data keys_file_data;
   std::string buf;
@@ -2255,7 +2255,7 @@ bool wallet2::load_keys(const std::string& keys_file_name, const std::string& pa
   r = ::serialization::parse_binary(buf, keys_file_data);
   THROW_WALLET_EXCEPTION_IF(!r, error::wallet_internal_error, "internal error: failed to deserialize \"" + keys_file_name + '\"');
   crypto::chacha8_key key;
-  crypto::generate_chacha8_key(password, key);
+  crypto::generate_chacha8_key(password.data(), password.size(), key);
   std::string account_data;
   account_data.resize(keys_file_data.account_data.size());
   crypto::chacha8(keys_file_data.account_data.data(), keys_file_data.account_data.size(), key, keys_file_data.iv, &account_data[0]);
@@ -2379,7 +2379,7 @@ bool wallet2::load_keys(const std::string& keys_file_name, const std::string& pa
  * can be used prior to rewriting wallet keys file, to ensure user has entered the correct password
  *
  */
-bool wallet2::verify_password(const std::string& password) const
+bool wallet2::verify_password(const epee::wipeable_string& password) const
 {
   return verify_password(m_keys_file, password, m_watch_only);
 }
@@ -2396,7 +2396,7 @@ bool wallet2::verify_password(const std::string& password) const
  * can be used prior to rewriting wallet keys file, to ensure user has entered the correct password
  *
  */
-bool wallet2::verify_password(const std::string& keys_file_name, const std::string& password, bool watch_only)
+bool wallet2::verify_password(const std::string& keys_file_name, const epee::wipeable_string& password, bool watch_only)
 {
   wallet2::keys_file_data keys_file_data;
   std::string buf;
@@ -2407,7 +2407,7 @@ bool wallet2::verify_password(const std::string& keys_file_name, const std::stri
   r = ::serialization::parse_binary(buf, keys_file_data);
   THROW_WALLET_EXCEPTION_IF(!r, error::wallet_internal_error, "internal error: failed to deserialize \"" + keys_file_name + '\"');
   crypto::chacha8_key key;
-  crypto::generate_chacha8_key(password, key);
+  crypto::generate_chacha8_key(password.data(), password.size(), key);
   std::string account_data;
   account_data.resize(keys_file_data.account_data.size());
   crypto::chacha8(keys_file_data.account_data.data(), keys_file_data.account_data.size(), key, keys_file_data.iv, &account_data[0]);
@@ -2444,7 +2444,7 @@ bool wallet2::verify_password(const std::string& keys_file_name, const std::stri
  * \param  two_random     Whether it is a non-deterministic wallet
  * \return                The secret key of the generated wallet
  */
-crypto::secret_key wallet2::generate(const std::string& wallet_, const std::string& password,
+crypto::secret_key wallet2::generate(const std::string& wallet_, const epee::wipeable_string& password,
   const crypto::secret_key& recovery_param, bool recover, bool two_random)
 {
   clear();
@@ -2511,7 +2511,7 @@ crypto::secret_key wallet2::generate(const std::string& wallet_, const std::stri
 * \param  password       Password of wallet file
 * \param  viewkey        view secret key
 */
-void wallet2::generate(const std::string& wallet_, const std::string& password,
+void wallet2::generate(const std::string& wallet_, const epee::wipeable_string& password,
   const cryptonote::account_public_address &account_public_address,
   const crypto::secret_key& viewkey)
 {
@@ -2547,7 +2547,7 @@ void wallet2::generate(const std::string& wallet_, const std::string& password,
 * \param  spendkey       spend secret key
 * \param  viewkey        view secret key
 */
-void wallet2::generate(const std::string& wallet_, const std::string& password,
+void wallet2::generate(const std::string& wallet_, const epee::wipeable_string& password,
   const cryptonote::account_public_address &account_public_address,
   const crypto::secret_key& spendkey, const crypto::secret_key& viewkey)
 {
@@ -2581,7 +2581,7 @@ void wallet2::generate(const std::string& wallet_, const std::string& password,
  * \param wallet_name Name of wallet file (should exist)
  * \param password    Password for wallet file
  */
-void wallet2::rewrite(const std::string& wallet_name, const std::string& password)
+void wallet2::rewrite(const std::string& wallet_name, const epee::wipeable_string& password)
 {
   prepare_file_names(wallet_name);
   boost::system::error_code ignored_ec;
@@ -2594,7 +2594,7 @@ void wallet2::rewrite(const std::string& wallet_name, const std::string& passwor
  * \param wallet_name Base name of wallet file
  * \param password    Password for wallet file
  */
-void wallet2::write_watch_only_wallet(const std::string& wallet_name, const std::string& password)
+void wallet2::write_watch_only_wallet(const std::string& wallet_name, const epee::wipeable_string& password)
 {
   prepare_file_names(wallet_name);
   boost::system::error_code ignored_ec;
@@ -2730,7 +2730,7 @@ bool wallet2::generate_chacha8_key_from_secret_keys(crypto::chacha8_key &key) co
   return true;
 }
 //----------------------------------------------------------------------------------------------------
-void wallet2::load(const std::string& wallet_, const std::string& password)
+void wallet2::load(const std::string& wallet_, const epee::wipeable_string& password)
 {
   clear();
   prepare_file_names(wallet_);
@@ -2881,10 +2881,10 @@ std::string wallet2::path() const
 //----------------------------------------------------------------------------------------------------
 void wallet2::store()
 {
-  store_to("", "");
+  store_to("", epee::wipeable_string());
 }
 //----------------------------------------------------------------------------------------------------
-void wallet2::store_to(const std::string &path, const std::string &password)
+void wallet2::store_to(const std::string &path, const epee::wipeable_string &password)
 {
   trim_hashchain();
 
diff --git a/src/wallet/wallet2.h b/src/wallet/wallet2.h
index ce0c67fc3..9308aadeb 100644
--- a/src/wallet/wallet2.h
+++ b/src/wallet/wallet2.h
@@ -168,7 +168,7 @@ namespace tools
     //! Just parses variables.
     static std::unique_ptr<wallet2> make_dummy(const boost::program_options::variables_map& vm, const std::function<boost::optional<password_container>(const char *, bool)> &password_prompter);
 
-    static bool verify_password(const std::string& keys_file_name, const std::string& password, bool watch_only);
+    static bool verify_password(const std::string& keys_file_name, const epee::wipeable_string& password, bool watch_only);
 
     wallet2(bool testnet = false, bool restricted = false) : m_run(true), m_callback(0), m_testnet(testnet), m_always_confirm_transfers(true), m_print_ring_members(false), m_store_tx_info(true), m_default_mixin(0), m_default_priority(0), m_refresh_type(RefreshDefault), m_auto_refresh(true), m_refresh_from_block_height(0), m_confirm_missing_payment_id(true), m_ask_password(true), m_min_output_count(0), m_min_output_value(0), m_merge_destinations(false), m_confirm_backlog(true), m_is_initialized(false), m_restricted(restricted), is_old_file_format(false), m_node_rpc_proxy(m_http_client, m_daemon_rpc_mutex), m_light_wallet(false), m_light_wallet_scanned_block_height(0), m_light_wallet_blockchain_height(0), m_light_wallet_connected(false), m_light_wallet_balance(0), m_light_wallet_unlocked_balance(0) {}
 
@@ -398,7 +398,7 @@ namespace tools
      * \param  two_random     Whether it is a non-deterministic wallet
      * \return                The secret key of the generated wallet
      */
-    crypto::secret_key generate(const std::string& wallet, const std::string& password,
+    crypto::secret_key generate(const std::string& wallet, const epee::wipeable_string& password,
       const crypto::secret_key& recovery_param = crypto::secret_key(), bool recover = false,
       bool two_random = false);
     /*!
@@ -408,7 +408,7 @@ namespace tools
      * \param  viewkey        view secret key
      * \param  spendkey       spend secret key
      */
-    void generate(const std::string& wallet, const std::string& password,
+    void generate(const std::string& wallet, const epee::wipeable_string& password,
       const cryptonote::account_public_address &account_public_address,
       const crypto::secret_key& spendkey, const crypto::secret_key& viewkey);
     /*!
@@ -417,7 +417,7 @@ namespace tools
      * \param  password       Password of wallet file
      * \param  viewkey        view secret key
      */
-    void generate(const std::string& wallet, const std::string& password,
+    void generate(const std::string& wallet, const epee::wipeable_string& password,
       const cryptonote::account_public_address &account_public_address,
       const crypto::secret_key& viewkey = crypto::secret_key());
     /*!
@@ -425,23 +425,23 @@ namespace tools
      * \param wallet_name Name of wallet file (should exist)
      * \param password    Password for wallet file
      */
-    void rewrite(const std::string& wallet_name, const std::string& password);
-    void write_watch_only_wallet(const std::string& wallet_name, const std::string& password);
-    void load(const std::string& wallet, const std::string& password);
+    void rewrite(const std::string& wallet_name, const epee::wipeable_string& password);
+    void write_watch_only_wallet(const std::string& wallet_name, const epee::wipeable_string& password);
+    void load(const std::string& wallet, const epee::wipeable_string& password);
     void store();
     /*!
      * \brief store_to - stores wallet to another file(s), deleting old ones
      * \param path     - path to the wallet file (keys and address filenames will be generated based on this filename)
      * \param password - password to protect new wallet (TODO: probably better save the password in the wallet object?)
      */
-    void store_to(const std::string &path, const std::string &password);
+    void store_to(const std::string &path, const epee::wipeable_string &password);
 
     std::string path() const;
 
     /*!
      * \brief verifies given password is correct for default wallet keys file
      */
-    bool verify_password(const std::string& password) const;
+    bool verify_password(const epee::wipeable_string& password) const;
     cryptonote::account_base& get_account(){return m_account;}
     const cryptonote::account_base& get_account()const{return m_account;}
 
@@ -466,7 +466,7 @@ namespace tools
      * \brief Checks if deterministic wallet
      */
     bool is_deterministic() const;
-    bool get_seed(std::string& electrum_words, const std::string &passphrase = std::string()) const;
+    bool get_seed(std::string& electrum_words, const epee::wipeable_string &passphrase = epee::wipeable_string()) const;
 
     /*!
     * \brief Checks if light wallet. A light wallet sends view key to a server where the blockchain is scanned.
@@ -838,13 +838,13 @@ namespace tools
      * \param  watch_only     true to save only view key, false to save both spend and view keys
      * \return                Whether it was successful.
      */
-    bool store_keys(const std::string& keys_file_name, const std::string& password, bool watch_only = false);
+    bool store_keys(const std::string& keys_file_name, const epee::wipeable_string& password, bool watch_only = false);
     /*!
      * \brief Load wallet information from wallet file.
      * \param keys_file_name Name of wallet file
      * \param password       Password of wallet file
      */
-    bool load_keys(const std::string& keys_file_name, const std::string& password);
+    bool load_keys(const std::string& keys_file_name, const epee::wipeable_string& password);
     void process_new_transaction(const crypto::hash &txid, const cryptonote::transaction& tx, const std::vector<uint64_t> &o_indices, uint64_t height, uint64_t ts, bool miner_tx, bool pool, bool double_spend_seen);
     void process_new_blockchain_entry(const cryptonote::block& b, const cryptonote::block_complete_entry& bche, const crypto::hash& bl_id, uint64_t height, const cryptonote::COMMAND_RPC_GET_BLOCKS_FAST::block_output_indices &o_indices);
     void detach_blockchain(uint64_t height);
diff --git a/src/wallet/wallet_rpc_server.cpp b/src/wallet/wallet_rpc_server.cpp
index c315684de..e790b9954 100644
--- a/src/wallet/wallet_rpc_server.cpp
+++ b/src/wallet/wallet_rpc_server.cpp
@@ -206,7 +206,8 @@ namespace tools
         }
         std::fputs(http_login->username.c_str(), rpc_login_file.handle());
         std::fputc(':', rpc_login_file.handle());
-        std::fputs(http_login->password.c_str(), rpc_login_file.handle());
+        const epee::wipeable_string password = http_login->password;
+        std::fwrite(password.data(), 1, password.size(), rpc_login_file.handle());
         std::fflush(rpc_login_file.handle());
         if (std::ferror(rpc_login_file.handle()))
         {