Don't allow relative -walletdir paths

Also warn if bitcoind is configured to use a relative -datadir path.

Specifying paths relative to the current working directory in a daemon process
can be dangerous, because files can fail to be located even if the
configuration doesn't change, but the daemon is started up differently.

Specifying a relative -datadir now adds a warning to the debug log. It would
not be backwards-compatible to forbid relative -datadir paths entirely, and it
could also be also inconvenient for command line testing.

Specifying a relative -walletdir now results in a startup error. But since the
-walletdir option is new in 0.16.0, there should be no compatibility issues.
Another reason not to use working directory paths for -walletdir specifically
is that the default -walletdir is a "wallets" subdirectory inside the datadir,
so it could be surprising that setting -walletdir manually would choose a
directory rooted in a completely different location.

1 files changed, 8 insertions, 4 deletions

diff --git a/src/wallet/init.cpp b/src/wallet/init.cpp
index 0f453f154..2d26f7ae0 100644
--- a/src/wallet/init.cpp
+++ b/src/wallet/init.cpp
@@ -205,11 +205,15 @@ bool VerifyWallets()
         return true;
     }
 
-    if (gArgs.IsArgSet("-walletdir") && !fs::is_directory(GetWalletDir())) {
-        if (fs::exists(fs::system_complete(gArgs.GetArg("-walletdir", "")))) {
-            return InitError(strprintf(_("Specified -walletdir \"%s\" is not a directory"), gArgs.GetArg("-walletdir", "").c_str()));
+    if (gArgs.IsArgSet("-walletdir")) {
+        fs::path wallet_dir = gArgs.GetArg("-walletdir", "");
+        if (!fs::exists(wallet_dir)) {
+            return InitError(strprintf(_("Specified -walletdir \"%s\" does not exist"), wallet_dir.string()));
+        } else if (!fs::is_directory(wallet_dir)) {
+            return InitError(strprintf(_("Specified -walletdir \"%s\" is not a directory"), wallet_dir.string()));
+        } else if (!wallet_dir.is_absolute()) {
+            return InitError(strprintf(_("Specified -walletdir \"%s\" is a relative path"), wallet_dir.string()));
         }
-        return InitError(strprintf(_("Specified -walletdir \"%s\" does not exist"), gArgs.GetArg("-walletdir", "").c_str()));
     }
 
     LogPrintf("Using wallet directory %s\n", GetWalletDir().string());