[master] MMS: New 'config_checksum' subcommand

2 files changed, 79 insertions, 25 deletions

diff --git a/src/wallet/message_store.cpp b/src/wallet/message_store.cpp
index 25a8bd4ef..fb07b42f0 100644
--- a/src/wallet/message_store.cpp
+++ b/src/wallet/message_store.cpp
@@ -39,6 +39,7 @@
 #include "serialization/binary_utils.h"
 #include "common/base58.h"
 #include "common/util.h"
+#include "common/utf8.h"
 #include "string_tools.h"
 
 
@@ -129,18 +130,18 @@ void message_store::set_signer(const multisig_wallet_state &state,
   authorized_signer &m = m_signers[index];
   if (label)
   {
-    m.label = label.get();
+    m.label = get_sanitized_text(label.get(), 50);
   }
   if (transport_address)
   {
-    m.transport_address = transport_address.get();
+    m.transport_address = get_sanitized_text(transport_address.get(), 200);
   }
   if (monero_address)
   {
     m.monero_address_known = true;
     m.monero_address = monero_address.get();
   }
-  // Save to minimize the chance to loose that info (at least while in beta)
+  // Save to minimize the chance to loose that info
   save(state);
 }
 
@@ -202,6 +203,13 @@ void message_store::unpack_signer_config(const multisig_wallet_state &state, con
   }
   uint32_t num_signers = (uint32_t)signers.size();
   THROW_WALLET_EXCEPTION_IF(num_signers != m_num_authorized_signers, tools::error::wallet_internal_error, "Wrong number of signers in config: " + std::to_string(num_signers));
+  for (uint32_t i = 0; i < num_signers; ++i)
+  {
+    authorized_signer &m = signers[i];
+    m.label = get_sanitized_text(m.label, 50);
+    m.transport_address = get_sanitized_text(m.transport_address, 200);
+    m.auto_config_token = get_sanitized_text(m.auto_config_token, 20);
+  }
 }
 
 void message_store::process_signer_config(const multisig_wallet_state &state, const std::string &signer_config)
@@ -242,10 +250,10 @@ void message_store::process_signer_config(const multisig_wallet_state &state, co
       }
     }
     authorized_signer &modify = m_signers[take_index];
-    modify.label = m.label;  // ALWAYS set label, see comments above
+    modify.label = get_sanitized_text(m.label, 50);  // ALWAYS set label, see comments above
     if (!modify.me)
     {
-      modify.transport_address = m.transport_address;
+      modify.transport_address = get_sanitized_text(m.transport_address, 200);
       modify.monero_address_known = m.monero_address_known;
       if (m.monero_address_known)
       {
@@ -392,6 +400,45 @@ void message_store::process_auto_config_data_message(uint32_t id)
   signer.auto_config_running = false;
 }
 
+void add_hash(crypto::hash &sum, const crypto::hash &summand)
+{
+  for (uint32_t i = 0; i < crypto::HASH_SIZE; ++i)
+  {
+    uint32_t x = (uint32_t)sum.data[i];
+    uint32_t y = (uint32_t)summand.data[i];
+    sum.data[i] = (char)((x + y) % 256);
+  }
+}
+
+// Calculate a checksum that allows signers to make sure they work with an identical signer config
+// by exchanging and comparing checksums out-of-band i.e. not using the MMS;
+// Because different signers have a different order of signers in the config work with "adding"
+// individual hashes because that operation is commutative
+std::string message_store::get_config_checksum() const
+{
+  crypto::hash sum = crypto::null_hash;
+  uint32_t num = SWAP32LE(m_num_authorized_signers);
+  add_hash(sum, crypto::cn_fast_hash(&num, sizeof(num)));
+  num = SWAP32LE(m_num_required_signers);
+  add_hash(sum, crypto::cn_fast_hash(&num, sizeof(num)));
+  for (uint32_t i = 0; i < m_num_authorized_signers; ++i)
+  {
+    const authorized_signer &m = m_signers[i];
+    add_hash(sum, crypto::cn_fast_hash(m.transport_address.data(), m.transport_address.size()));
+    if (m.monero_address_known)
+    {
+      add_hash(sum, crypto::cn_fast_hash(&m.monero_address.m_spend_public_key, sizeof(m.monero_address.m_spend_public_key)));
+      add_hash(sum, crypto::cn_fast_hash(&m.monero_address.m_view_public_key, sizeof(m.monero_address.m_view_public_key)));
+    }
+  }
+  std::string checksum_bytes;
+  checksum_bytes += sum.data[0];
+  checksum_bytes += sum.data[1];
+  checksum_bytes += sum.data[2];
+  checksum_bytes += sum.data[3];
+  return epee::string_tools::buff_to_hex_nodelimer(checksum_bytes);
+}
+
 void message_store::stop_auto_config()
 {
   for (uint32_t i = 0; i < m_num_authorized_signers; ++i)
@@ -661,32 +708,38 @@ void message_store::delete_all_messages()
   m_messages.clear();
 }
 
-// Make a message text, which is "attacker controlled data", reasonably safe to display
+// Make a text, which is "attacker controlled data", reasonably safe to display
 // This is mostly geared towards the safe display of notes sent by "mms note" with a "mms show" command
-void message_store::get_sanitized_message_text(const message &m, std::string &sanitized_text) const
+std::string message_store::get_sanitized_text(const std::string &text, size_t max_length)
 {
-  sanitized_text.clear();
-
   // Restrict the size to fend of DOS-style attacks with heaps of data
-  size_t length = std::min(m.content.length(), (size_t)1000);
+  size_t length = std::min(text.length(), max_length);
+  std::string sanitized_text = text.substr(0, length);
 
-  for (size_t i = 0; i < length; ++i)
+  try
   {
-    char c = m.content[i];
-    if ((int)c < 32)
+    sanitized_text = tools::utf8canonical(sanitized_text, [](wint_t c)
     {
-      // Strip out any controls, especially ESC for getting rid of potentially dangerous
-      // ANSI escape sequences that a console window might interpret
-      c = ' ';
-    }
-    else if ((c == '<') || (c == '>'))
-    {
-      // Make XML or HTML impossible that e.g. might contain scripts that Qt might execute
-      // when displayed in the GUI wallet
-      c = ' ';
-    }
-    sanitized_text += c;
+      if ((c < 0x20) || (c == 0x7f) || (c >= 0x80 && c <= 0x9f))
+      {
+        // Strip out any controls, especially ESC for getting rid of potentially dangerous
+        // ANSI escape sequences that a console window might interpret
+        c = '?';
+      }
+      else if ((c == '<') || (c == '>'))
+      {
+        // Make XML or HTML impossible that e.g. might contain scripts that Qt might execute
+        // when displayed in the GUI wallet
+        c = '?';
+      }
+      return c;
+    });
+  }
+  catch (const std::exception &e)
+  {
+    sanitized_text = "(Illegal UTF-8 string)";
   }
+  return sanitized_text;
 }
 
 void message_store::write_to_file(const multisig_wallet_state &state, const std::string &filename)
diff --git a/src/wallet/message_store.h b/src/wallet/message_store.h
index d40daf186..9055fd776 100644
--- a/src/wallet/message_store.h
+++ b/src/wallet/message_store.h
@@ -242,6 +242,7 @@ namespace mms
     size_t add_auto_config_data_message(const multisig_wallet_state &state,
                                         const std::string &auto_config_token);
     void process_auto_config_data_message(uint32_t id);
+    std::string get_config_checksum() const;
     void stop_auto_config();
 
     // Process data just created by "me" i.e. the own local wallet, e.g. as the result of a "prepare_multisig" command
@@ -275,7 +276,7 @@ namespace mms
     void set_message_processed_or_sent(uint32_t id);
     void delete_message(uint32_t id);
     void delete_all_messages();
-    void get_sanitized_message_text(const message &m, std::string &sanitized_text) const;
+    static std::string get_sanitized_text(const std::string &text, size_t max_length);
 
     void send_message(const multisig_wallet_state &state, uint32_t id);
     bool check_for_messages(const multisig_wallet_state &state, std::vector<message> &messages);