Reject invalid wallet files

src/wallet/wallet.cpp

@@ -482,6 +482,10 @@ bool CWallet::Verify()
 
         fs::path wallet_path = fs::absolute(walletFile, GetDataDir());
 
+        if (fs::exists(wallet_path) && (!fs::is_regular_file(wallet_path) || fs::is_symlink(wallet_path))) {
+            return InitError(_("Invalid -wallet file"));
+        }
+
         if (!wallet_paths.insert(wallet_path).second) {
             return InitError(_("Duplicate -wallet filename"));
         }

test/functional/multiwallet.py

@@ -6,6 +6,8 @@
 
 Verify that a bitcoind node can load multiple wallet files
 """
+import os
+
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import assert_equal, assert_raises_jsonrpc
 
@@ -23,6 +25,14 @@ class MultiWalletTest(BitcoinTestFramework):
         # should not initialize if there are duplicate wallets
         self.assert_start_raises_init_error(0, self.options.tmpdir, ['-wallet=w1', '-wallet=w1'], 'Duplicate -wallet filename')
 
+        # should not initialize if wallet file is a directory
+        os.mkdir(os.path.join(self.options.tmpdir, 'node0', 'regtest', 'w11'))
+        self.assert_start_raises_init_error(0, self.options.tmpdir, ['-wallet=w11'], 'Invalid -wallet file')
+
+        # should not initialize if wallet file is a symlink
+        os.symlink(os.path.join(self.options.tmpdir, 'node0', 'regtest', 'w1'), os.path.join(self.options.tmpdir, 'node0', 'regtest', 'w12'))
+        self.assert_start_raises_init_error(0, self.options.tmpdir, ['-wallet=w12'], 'Invalid -wallet file')
+
         self.nodes[0] = self.start_node(0, self.options.tmpdir, self.extra_args[0])
 
         w1 = self.nodes[0] / "wallet/w1"