Merge pull request #6238

f717d593 wallet2: guard against race with multiple decrypt_keys users (moneromooo-monero)

src/wallet/wallet2.cpp

@@ -1186,6 +1186,7 @@ wallet2::wallet2(network_type nettype, uint64_t kdf_rounds, bool unattended):
   m_ringdb(),
   m_last_block_reward(0),
   m_encrypt_keys_after_refresh(boost::none),
+  m_decrypt_keys_lockers(0),
   m_unattended(unattended),
   m_devices_registered(false),
   m_device_last_key_image_sync(0),
@@ -4371,12 +4372,18 @@ bool wallet2::verify_password(const std::string& keys_file_name, const epee::wip
 
 void wallet2::encrypt_keys(const crypto::chacha_key &key)
 {
+  boost::lock_guard<boost::mutex> lock(m_decrypt_keys_lock);
+  if (--m_decrypt_keys_lockers) // another lock left ?
+    return;
   m_account.encrypt_keys(key);
   m_account.decrypt_viewkey(key);
 }
 
 void wallet2::decrypt_keys(const crypto::chacha_key &key)
 {
+  boost::lock_guard<boost::mutex> lock(m_decrypt_keys_lock);
+  if (m_decrypt_keys_lockers++) // already unlocked ?
+    return;
   m_account.encrypt_viewkey(key);
   m_account.decrypt_keys(key);
 }

src/wallet/wallet2.h

@@ -1618,6 +1618,8 @@ private:
 
     crypto::chacha_key m_cache_key;
     boost::optional<epee::wipeable_string> m_encrypt_keys_after_refresh;
+    boost::mutex m_decrypt_keys_lock;
+    unsigned int m_decrypt_keys_lockers;
 
     bool m_unattended;
     bool m_devices_registered;