Merge #19655: rpc: Catch listsinceblock target_confirmations exceeding block count

c133cdcdc3397a734d57e05494682bf9bf6f4c15 Cap listsinceblock target_confirmations param (Adam Stein)

Pull request description:

  This addresses an issue brought up in #19587.

  Currently, the `target_confirmations` parameter to `listsinceblock` is not checked for being too large. When `target_confirmations` is greater than one more than the current number of blocks, `listsinceblock` fails with error code -1. In comparison, when `target_confirmations` is less than 1,  a -8 "Invalid parameter" error code is thrown.

  This PR fixes the issue by returning a -8 "Invalid parameter" error if the `target_confirmations` value corresponds to a block with more confirmations than the genesis block. This happens if `target_confirmations` exceeds one more than the number of blocks.

ACKs for top commit:
  laanwj:
    Code review ACK c133cdcdc3397a734d57e05494682bf9bf6f4c15
  ryanofsky:
    Code review ACK c133cdcdc3397a734d57e05494682bf9bf6f4c15. Just suggested changes since last review. Thanks!

Tree-SHA512: 02680f4cb937d2c24d5019abd0ebfa188b8a50679a1e64e9c26bfe5c17eef6aea906832e6e2d492ba8a2ea160041bf185d66795ee691e340f6793db03c21b89a

1 files changed, 2 insertions, 1 deletions

diff --git a/src/wallet/rpcwallet.cpp b/src/wallet/rpcwallet.cpp
index 17460a2932..7956533766 100644
--- a/src/wallet/rpcwallet.cpp
+++ b/src/wallet/rpcwallet.cpp
@@ -1484,7 +1484,7 @@ static UniValue listsinceblock(const JSONRPCRequest& request)
                         {RPCResult::Type::ARR, "removed", "<structure is the same as \"transactions\" above, only present if include_removed=true>\n"
                             "Note: transactions that were re-added in the active chain will appear as-is in this array, and may thus have a positive confirmation count."
                         , {{RPCResult::Type::ELISION, "", ""},}},
-                        {RPCResult::Type::STR_HEX, "lastblock", "The hash of the block (target_confirmations-1) from the best block on the main chain. This is typically used to feed back into listsinceblock the next time you call it. So you would generally use a target_confirmations of say 6, so you will be continually re-notified of transactions until they've reached 6 confirmations plus any new ones"},
+                        {RPCResult::Type::STR_HEX, "lastblock", "The hash of the block (target_confirmations-1) from the best block on the main chain, or the genesis hash if the referenced block does not exist yet. This is typically used to feed back into listsinceblock the next time you call it. So you would generally use a target_confirmations of say 6, so you will be continually re-notified of transactions until they've reached 6 confirmations plus any new ones"},
                     }
                 },
                 RPCExamples{
@@ -1567,6 +1567,7 @@ static UniValue listsinceblock(const JSONRPCRequest& request)
     }
 
     uint256 lastblock;
+    target_confirms = std::min(target_confirms, wallet.GetLastBlockHeight() + 1);
     CHECK_NONFATAL(wallet.chain().findAncestorByHeight(wallet.GetLastBlockHash(), wallet.GetLastBlockHeight() + 1 - target_confirms, FoundBlock().hash(lastblock)));
 
     UniValue ret(UniValue::VOBJ);