Merge bitcoin-core/gui#631: Disallow encryption of watchonly wallets

4c495413e138ec1dd6874e41b44e689f0c15e0e3 Disallow encryption of watchonly wallets (Andrew Chow)

Pull request description:

  Watchonly wallets do not have any private keys to encrypt. It does not make sense to encrypt such wallets, so disable the option to encrypt them.

  This avoids an assertion that can be hit when encrypting watchonly descriptor wallets.

  As our current behavior allows for encrypting watchonly wallets (no crash with legacy, crash, but still encrypted with descriptors), the new `NoKeys` status is only returned for unencrypted watchonly wallets. This allows any watchonly wallets that were previously encrypted to show the correct encryption status (they have encryption keys, and so should be indicated as being encrypted).

ACKs for top commit:
  w0xlt:
    tACK https://github.com/bitcoin-core/gui/pull/631/commits/4c495413e138ec1dd6874e41b44e689f0c15e0e3
  hebasto:
    ACK 4c495413e138ec1dd6874e41b44e689f0c15e0e3, tested on Ubuntu 22.04.

Tree-SHA512: 054dba0a8c1343a0df17689508cd628a974555828955a3c8820bf020868b95a3df98c47253b0ffe2252765b020160bb76ea21647d76d59ba748b3b41c481f2ae

3 files changed, 12 insertions, 0 deletions

diff --git a/src/qt/bitcoingui.cpp b/src/qt/bitcoingui.cpp
index 35e32f515b..baad0fdd91 100644
--- a/src/qt/bitcoingui.cpp
+++ b/src/qt/bitcoingui.cpp
@@ -1350,6 +1350,12 @@ void BitcoinGUI::setEncryptionStatus(int status)
 {
     switch(status)
     {
+    case WalletModel::NoKeys:
+        labelWalletEncryptionIcon->hide();
+        encryptWalletAction->setChecked(false);
+        changePassphraseAction->setEnabled(false);
+        encryptWalletAction->setEnabled(false);
+        break;
     case WalletModel::Unencrypted:
         labelWalletEncryptionIcon->hide();
         encryptWalletAction->setChecked(false);
diff --git a/src/qt/walletmodel.cpp b/src/qt/walletmodel.cpp
index bb6079afee..fde136b727 100644
--- a/src/qt/walletmodel.cpp
+++ b/src/qt/walletmodel.cpp
@@ -306,6 +306,11 @@ WalletModel::EncryptionStatus WalletModel::getEncryptionStatus() const
 {
     if(!m_wallet->isCrypted())
     {
+        // A previous bug allowed for watchonly wallets to be encrypted (encryption keys set, but nothing is actually encrypted).
+        // To avoid misrepresenting the encryption status of such wallets, we only return NoKeys for watchonly wallets that are unencrypted.
+        if (m_wallet->privateKeysDisabled()) {
+            return NoKeys;
+        }
         return Unencrypted;
     }
     else if(m_wallet->isLocked())
diff --git a/src/qt/walletmodel.h b/src/qt/walletmodel.h
index a52290dee8..0184fb8ec2 100644
--- a/src/qt/walletmodel.h
+++ b/src/qt/walletmodel.h
@@ -71,6 +71,7 @@ public:
 
     enum EncryptionStatus
     {
+        NoKeys,       // wallet->IsWalletFlagSet(WALLET_FLAG_DISABLE_PRIVATE_KEYS)
         Unencrypted,  // !wallet->IsCrypted()
         Locked,       // wallet->IsCrypted() && wallet->IsLocked()
         Unlocked      // wallet->IsCrypted() && !wallet->IsLocked()