Merge bitcoin/bitcoin#26186: rpc: Sanitize label name in various RPCs with tests

65e78bda7cd23ad7b6ede63c6bf5ffe6f552c71d test: Invalid label name coverage (Aurèle Oulès)
552b51e682b5a52d9e2fbe64e44e623451692bd3 refactor: Add sanity checks in LabelFromValue (Aurèle Oulès)
67e7ba8e1aea58fc864f9bb1fc0e56b70777185e rpc: Sanitize label name in various RPCs (Aurèle Oulès)

Pull request description:

  The following RPCs did not sanitize the optional label name:
  - importprivkey
  - importaddress
  - importpubkey
  - importmulti
  - importdescriptors
  - listsinceblock

  Thus is was possible to import an address with a label `*` which should not be possible.
  The wildcard label is used for backwards compatibility in the `listtransactions` rpc.
  I added test coverage for these RPCs.

ACKs for top commit:
  ajtowns:
    ACK 65e78bda7cd23ad7b6ede63c6bf5ffe6f552c71d
  achow101:
    ACK 65e78bda7cd23ad7b6ede63c6bf5ffe6f552c71d
  furszy:
    diff ACK 65e78bd
  stickies-v:
    re-ACK 65e78bda7cd23ad7b6ede63c6bf5ffe6f552c71d
  theStack:
    re-ACK 65e78bda7cd23ad7b6ede63c6bf5ffe6f552c71d

Tree-SHA512: ad99f2824d4cfae352166b76da4ca0069b7c2eccf81aaa0654be25bbb3c6e5d6b005d93960f3f4154155f80e12be2d0cebd5529922ae3d2a36ee4eed82440b31

1 files changed, 5 insertions, 11 deletions

diff --git a/src/wallet/rpc/backup.cpp b/src/wallet/rpc/backup.cpp
index 95117b6c19..64253789ec 100644
--- a/src/wallet/rpc/backup.cpp
+++ b/src/wallet/rpc/backup.cpp
@@ -156,9 +156,7 @@ RPCHelpMan importprivkey()
         EnsureWalletIsUnlocked(*pwallet);
 
         std::string strSecret = request.params[0].get_str();
-        std::string strLabel;
-        if (!request.params[1].isNull())
-            strLabel = request.params[1].get_str();
+        const std::string strLabel{LabelFromValue(request.params[1])};
 
         // Whether to perform rescan after import
         if (!request.params[2].isNull())
@@ -249,9 +247,7 @@ RPCHelpMan importaddress()
 
     EnsureLegacyScriptPubKeyMan(*pwallet, true);
 
-    std::string strLabel;
-    if (!request.params[1].isNull())
-        strLabel = request.params[1].get_str();
+    const std::string strLabel{LabelFromValue(request.params[1])};
 
     // Whether to perform rescan after import
     bool fRescan = true;
@@ -442,9 +438,7 @@ RPCHelpMan importpubkey()
 
     EnsureLegacyScriptPubKeyMan(*pwallet, true);
 
-    std::string strLabel;
-    if (!request.params[1].isNull())
-        strLabel = request.params[1].get_str();
+    const std::string strLabel{LabelFromValue(request.params[1])};
 
     // Whether to perform rescan after import
     bool fRescan = true;
@@ -1170,7 +1164,7 @@ static UniValue ProcessImport(CWallet& wallet, const UniValue& data, const int64
         if (internal && data.exists("label")) {
             throw JSONRPCError(RPC_INVALID_PARAMETER, "Internal addresses should not have a label");
         }
-        const std::string& label = data.exists("label") ? data["label"].get_str() : "";
+        const std::string label{LabelFromValue(data["label"])};
         const bool add_keypool = data.exists("keypool") ? data["keypool"].get_bool() : false;
 
         // Add to keypool only works with privkeys disabled
@@ -1464,7 +1458,7 @@ static UniValue ProcessDescriptorImport(CWallet& wallet, const UniValue& data, c
         const std::string& descriptor = data["desc"].get_str();
         const bool active = data.exists("active") ? data["active"].get_bool() : false;
         const bool internal = data.exists("internal") ? data["internal"].get_bool() : false;
-        const std::string& label = data.exists("label") ? data["label"].get_str() : "";
+        const std::string label{LabelFromValue(data["label"])};
 
         // Parse descriptor string
         FlatSigningProvider keys;