Determine inactive HD seeds from key metadata and track them in LegacyScriptPubKeyMan

src/wallet/scriptpubkeyman.cpp

@@ -839,12 +839,29 @@ bool LegacyScriptPubKeyMan::AddWatchOnly(const CScript& dest, int64_t nCreateTim
 void LegacyScriptPubKeyMan::SetHDChain(const CHDChain& chain, bool memonly)
 {
     LOCK(cs_KeyStore);
-    if (!memonly && !WalletBatch(m_storage.GetDatabase()).WriteHDChain(chain))
+    // memonly == true means we are loading the wallet file
+    // memonly == false means that the chain is actually being changed
+    if (!memonly) {
+        // Store the new chain
+        if (!WalletBatch(m_storage.GetDatabase()).WriteHDChain(chain)) {
             throw std::runtime_error(std::string(__func__) + ": writing chain failed");
+        }
+        // When there's an old chain, add it as an inactive chain as we are now rotating hd chains
+        if (!m_hd_chain.seed_id.IsNull()) {
+            AddInactiveHDChain(m_hd_chain);
+        }
+    }
 
     m_hd_chain = chain;
 }
 
+void LegacyScriptPubKeyMan::AddInactiveHDChain(const CHDChain& chain)
+{
+    LOCK(cs_KeyStore);
+    assert(!chain.seed_id.IsNull());
+    m_inactive_hd_chains[chain.seed_id] = chain;
+}
+
 bool LegacyScriptPubKeyMan::HaveKey(const CKeyID &address) const
 {
     LOCK(cs_KeyStore);
@@ -1011,8 +1028,8 @@ void LegacyScriptPubKeyMan::DeriveNewChildKey(WalletBatch &batch, CKeyMetadata&
     std::copy(master_id.begin(), master_id.begin() + 4, metadata.key_origin.fingerprint);
     metadata.has_key_origin = true;
     // update the chain model in the database
-    if (!batch.WriteHDChain(hd_chain))
-        throw std::runtime_error(std::string(__func__) + ": Writing HD chain model failed");
+    if (hd_chain.seed_id == m_hd_chain.seed_id && !batch.WriteHDChain(hd_chain))
+        throw std::runtime_error(std::string(__func__) + ": writing HD chain model failed");
 }
 
 void LegacyScriptPubKeyMan::LoadKeyPool(int64_t nIndex, const CKeyPool &keypool)

src/wallet/scriptpubkeyman.h

@@ -18,6 +18,8 @@
 
 #include <boost/signals2/signal.hpp>
 
+#include <unordered_map>
+
 enum class OutputType;
 
 // Wallet storage things that ScriptPubKeyMans need in order to be able to store things to the wallet database.
@@ -143,6 +145,17 @@ public:
     }
 };
 
+class KeyIDHasher
+{
+public:
+    KeyIDHasher() {}
+
+    size_t operator()(const CKeyID& id) const
+    {
+        return id.GetUint64(0);
+    }
+};
+
 /*
  * A class implementing ScriptPubKeyMan manages some (or all) scriptPubKeys used in a wallet.
  * It contains the scripts and keys related to the scriptPubKeys it manages.
@@ -288,6 +301,7 @@ private:
 
     /* the HD chain data model (external chain counters) */
     CHDChain m_hd_chain;
+    std::unordered_map<CKeyID, CHDChain, KeyIDHasher> m_inactive_hd_chains;
 
     /* HD derive new child key (on internal or external chain) */
     void DeriveNewChildKey(WalletBatch& batch, CKeyMetadata& metadata, CKey& secret, CHDChain& hd_chain, bool internal = false) EXCLUSIVE_LOCKS_REQUIRED(cs_KeyStore);
@@ -397,6 +411,7 @@ public:
     /* Set the HD chain model (chain child index counters) */
     void SetHDChain(const CHDChain& chain, bool memonly);
     const CHDChain& GetHDChain() const { return m_hd_chain; }
+    void AddInactiveHDChain(const CHDChain& chain);
 
     //! Adds a watch-only address to the store, without saving it to disk (used by LoadWallet)
     bool LoadWatchOnly(const CScript &dest);

src/wallet/walletdb.cpp

@@ -10,6 +10,7 @@
 #include <protocol.h>
 #include <serialize.h>
 #include <sync.h>
+#include <util/bip32.h>
 #include <util/system.h>
 #include <util/time.h>
 #include <wallet/wallet.h>
@@ -245,6 +246,7 @@ public:
     std::map<uint256, DescriptorCache> m_descriptor_caches;
     std::map<std::pair<uint256, CKeyID>, CKey> m_descriptor_keys;
     std::map<std::pair<uint256, CKeyID>, std::pair<CPubKey, std::vector<unsigned char>>> m_descriptor_crypt_keys;
+    std::map<uint160, CHDChain> m_hd_chains;
 
     CWalletScanState() {
     }
@@ -405,6 +407,65 @@ ReadKeyValue(CWallet* pwallet, CDataStream& ssKey, CDataStream& ssValue,
             ssValue >> keyMeta;
             wss.nKeyMeta++;
             pwallet->GetOrCreateLegacyScriptPubKeyMan()->LoadKeyMetadata(vchPubKey.GetID(), keyMeta);
+
+            // Extract some CHDChain info from this metadata if it has any
+            if (keyMeta.nVersion >= CKeyMetadata::VERSION_WITH_HDDATA && !keyMeta.hd_seed_id.IsNull() && keyMeta.hdKeypath.size() > 0) {
+                // Get the path from the key origin or from the path string
+                // Not applicable when path is "s" as that indicates a seed
+                bool internal = false;
+                uint32_t index = 0;
+                if (keyMeta.hdKeypath != "s") {
+                    std::vector<uint32_t> path;
+                    if (keyMeta.has_key_origin) {
+                        // We have a key origin, so pull it from its path vector
+                        path = keyMeta.key_origin.path;
+                    } else {
+                        // No key origin, have to parse the string
+                        if (!ParseHDKeypath(keyMeta.hdKeypath, path)) {
+                            strErr = "Error reading wallet database: keymeta with invalid HD keypath";
+                            return false;
+                        }
+                    }
+
+                    // Extract the index and internal from the path
+                    // Path string is m/0'/k'/i'
+                    // Path vector is [0', k', i'] (but as ints OR'd with the hardened bit
+                    // k == 0 for external, 1 for internal. i is the index
+                    if (path.size() != 3) {
+                        strErr = "Error reading wallet database: keymeta found with unexpected path";
+                        return false;
+                    }
+                    if (path[0] != 0x80000000) {
+                        strErr = strprintf("Unexpected path index of 0x%08x (expected 0x80000000) for the element at index 0", path[0]);
+                        return false;
+                    }
+                    if (path[1] != 0x80000000 && path[1] != (1 | 0x80000000)) {
+                        strErr = strprintf("Unexpected path index of 0x%08x (expected 0x80000000 or 0x80000001) for the element at index 1", path[1]);
+                        return false;
+                    }
+                    if ((path[2] & 0x80000000) == 0) {
+                        strErr = strprintf("Unexpected path index of 0x%08x (expected to be greater than or equal to 0x80000000)", path[2]);
+                        return false;
+                    }
+                    internal = path[1] == (1 | 0x80000000);
+                    index = path[2] & ~0x80000000;
+                }
+
+                // Insert a new CHDChain, or get the one that already exists
+                auto ins = wss.m_hd_chains.emplace(keyMeta.hd_seed_id, CHDChain());
+                CHDChain& chain = ins.first->second;
+                if (ins.second) {
+                    // For new chains, we want to default to VERSION_HD_BASE until we see an internal
+                    chain.nVersion = CHDChain::VERSION_HD_BASE;
+                    chain.seed_id = keyMeta.hd_seed_id;
+                }
+                if (internal) {
+                    chain.nVersion = CHDChain::VERSION_HD_CHAIN_SPLIT;
+                    chain.nInternalChainCounter = std::max(chain.nInternalChainCounter, index);
+                } else {
+                    chain.nExternalChainCounter = std::max(chain.nExternalChainCounter, index);
+                }
+            }
         } else if (strType == DBKeys::WATCHMETA) {
             CScript script;
             ssKey >> script;
@@ -728,6 +789,20 @@ DBErrors WalletBatch::LoadWallet(CWallet* pwallet)
         result = DBErrors::CORRUPT;
     }
 
+    // Set the inactive chain
+    if (wss.m_hd_chains.size() > 0) {
+        LegacyScriptPubKeyMan* legacy_spkm = pwallet->GetLegacyScriptPubKeyMan();
+        if (!legacy_spkm) {
+            pwallet->WalletLogPrintf("Inactive HD Chains found but no Legacy ScriptPubKeyMan\n");
+            return DBErrors::CORRUPT;
+        }
+        for (const auto& chain_pair : wss.m_hd_chains) {
+            if (chain_pair.first != pwallet->GetLegacyScriptPubKeyMan()->GetHDChain().seed_id) {
+                pwallet->GetLegacyScriptPubKeyMan()->AddInactiveHDChain(chain_pair.second);
+            }
+        }
+    }
+
     return result;
 }
 

src/wallet/walletdb.h

@@ -116,6 +116,11 @@ public:
         nInternalChainCounter = 0;
         seed_id.SetNull();
     }
+
+    bool operator==(const CHDChain& chain) const
+    {
+        return seed_id == chain.seed_id;
+    }
 };
 
 class CKeyMetadata