wallet2: fix rescanning tx via scan_tx

- Detach & re-process txs >= lowest scan height
- ensures that if a user calls scan_tx(tx1) after scanning tx2,
the wallet correctly processes tx1 and tx2
- if a user provides a tx with a height higher than the wallet's
last scanned height, the wallet will scan starting from that tx's
height
- scan_tx requires trusted daemon iff need to re-process existing
txs: in addition to querying a daemon for txids, if a user
provides a txid of a tx with height *lower* than any *already*
scanned txs in the wallet, then the wallet will also query the
daemon for all the *higher* txs as well. This is likely
unexpected behavior to a caller, and so to protect a caller from
revealing txid's to an untrusted daemon in an unexpected way,
require the daemon be trusted.

1 files changed, 34 insertions, 3 deletions

diff --git a/src/wallet/wallet2.h b/src/wallet/wallet2.h
index 5e922494b..554a766bf 100644
--- a/src/wallet/wallet2.h
+++ b/src/wallet/wallet2.h
@@ -810,6 +810,30 @@ private:
       bool empty() const { return tx_extra_fields.empty() && primary.empty() && additional.empty(); }
     };
 
+    struct detached_blockchain_data
+    {
+      hashchain detached_blockchain;
+      size_t original_chain_size;
+      std::unordered_set<crypto::hash> detached_tx_hashes;
+      std::unordered_map<crypto::hash, std::vector<cryptonote::tx_destination_entry>> detached_confirmed_txs_dests;
+    };
+
+    struct process_tx_entry_t
+    {
+      cryptonote::COMMAND_RPC_GET_TRANSACTIONS::entry tx_entry;
+      cryptonote::transaction tx;
+      crypto::hash tx_hash;
+    };
+
+    struct tx_entry_data
+    {
+      std::vector<process_tx_entry_t> tx_entries;
+      uint64_t lowest_height;
+      uint64_t highest_height;
+
+      tx_entry_data(): lowest_height((uint64_t)-1), highest_height(0) {}
+    };
+
     /*!
      * \brief  Generates a wallet or restores one. Assumes the multisig setup
       *        has already completed for the provided multisig info.
@@ -1360,7 +1384,7 @@ private:
     std::string get_spend_proof(const crypto::hash &txid, const std::string &message);
     bool check_spend_proof(const crypto::hash &txid, const std::string &message, const std::string &sig_str);
 
-    void scan_tx(const std::vector<crypto::hash> &txids);
+    void scan_tx(const std::unordered_set<crypto::hash> &txids);
 
     /*!
      * \brief  Generates a proof that proves the reserve of unspent funds
@@ -1644,10 +1668,11 @@ private:
      */
     bool load_keys_buf(const std::string& keys_buf, const epee::wipeable_string& password);
     bool load_keys_buf(const std::string& keys_buf, const epee::wipeable_string& password, boost::optional<crypto::chacha_key>& keys_to_encrypt);
-    void process_new_transaction(const crypto::hash &txid, const cryptonote::transaction& tx, const std::vector<uint64_t> &o_indices, uint64_t height, uint8_t block_version, uint64_t ts, bool miner_tx, bool pool, bool double_spend_seen, const tx_cache_data &tx_cache_data, std::map<std::pair<uint64_t, uint64_t>, size_t> *output_tracker_cache = NULL);
+    void process_new_transaction(const crypto::hash &txid, const cryptonote::transaction& tx, const std::vector<uint64_t> &o_indices, uint64_t height, uint8_t block_version, uint64_t ts, bool miner_tx, bool pool, bool double_spend_seen, const tx_cache_data &tx_cache_data, std::map<std::pair<uint64_t, uint64_t>, size_t> *output_tracker_cache = NULL, bool ignore_callbacks = false);
     bool should_skip_block(const cryptonote::block &b, uint64_t height) const;
     void process_new_blockchain_entry(const cryptonote::block& b, const cryptonote::block_complete_entry& bche, const parsed_block &parsed_block, const crypto::hash& bl_id, uint64_t height, const std::vector<tx_cache_data> &tx_cache_data, size_t tx_cache_data_offset, std::map<std::pair<uint64_t, uint64_t>, size_t> *output_tracker_cache = NULL);
-    void detach_blockchain(uint64_t height, std::map<std::pair<uint64_t, uint64_t>, size_t> *output_tracker_cache = NULL);
+    detached_blockchain_data detach_blockchain(uint64_t height, std::map<std::pair<uint64_t, uint64_t>, size_t> *output_tracker_cache = NULL);
+    void handle_reorg(uint64_t height, std::map<std::pair<uint64_t, uint64_t>, size_t> *output_tracker_cache = NULL);
     void get_short_chain_history(std::list<crypto::hash>& ids, uint64_t granularity = 1) const;
     bool clear();
     void clear_soft(bool keep_key_images=false);
@@ -1703,6 +1728,9 @@ private:
     crypto::chacha_key get_ringdb_key();
     void setup_keys(const epee::wipeable_string &password);
     size_t get_transfer_details(const crypto::key_image &ki) const;
+    tx_entry_data get_tx_entries(const std::unordered_set<crypto::hash> &txids);
+    void sort_scan_tx_entries(std::vector<process_tx_entry_t> &unsorted_tx_entries);
+    void process_scan_txs(const tx_entry_data &txs_to_scan, const tx_entry_data &txs_to_reprocess, const std::unordered_set<crypto::hash> &tx_hashes_to_reprocess, detached_blockchain_data &dbd);
 
     void register_devices();
     hw::device& lookup_device(const std::string & device_descriptor);
@@ -1793,6 +1821,9 @@ private:
     // m_refresh_from_block_height was defaulted to zero.*/
     bool m_explicit_refresh_from_block_height;
     uint64_t m_pool_info_query_time;
+    uint64_t m_skip_to_height;
+    // m_skip_to_height is useful when we don't want to modify the wallet's restore height.
+    // m_refresh_from_block_height is also a wallet's restore height which should remain constant unless explicitly modified by the user.
     bool m_confirm_non_default_ring_size;
     AskPasswordType m_ask_password;
     uint64_t m_max_reorg_depth;