rpc: Actually throw help when passed invalid number of params

src/rpc/blockchain.cpp

@@ -1,5 +1,5 @@
 // Copyright (c) 2010 Satoshi Nakamoto
-// Copyright (c) 2009-2018 The Bitcoin Core developers
+// Copyright (c) 2009-2019 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
@@ -1778,9 +1778,7 @@ static constexpr size_t PER_UTXO_OVERHEAD = sizeof(COutPoint) + sizeof(uint32_t)
 
 static UniValue getblockstats(const JSONRPCRequest& request)
 {
-    if (request.fHelp || request.params.size() < 1 || request.params.size() > 4) {
-        throw std::runtime_error(
-            RPCHelpMan{"getblockstats",
+    const RPCHelpMan help{"getblockstats",
                 "\nCompute per block statistics for a given window. All amounts are in satoshis.\n"
                 "It won't work for some heights with pruning.\n"
                 "It won't work without -txindex for utxo_size_inc, *fee or *feerate stats.\n",
@@ -1836,7 +1834,9 @@ static UniValue getblockstats(const JSONRPCRequest& request)
                     HelpExampleCli("getblockstats", "1000 '[\"minfeerate\",\"avgfeerate\"]'")
             + HelpExampleRpc("getblockstats", "1000 '[\"minfeerate\",\"avgfeerate\"]'")
                 },
-            }.ToString());
+    };
+    if (request.fHelp || !help.IsValidNumArgs(request.params.size())) {
+        throw std::runtime_error(help.ToString());
     }
 
     LOCK(cs_main);

src/rpc/net.cpp

@@ -523,13 +523,7 @@ static UniValue getnetworkinfo(const JSONRPCRequest& request)
 
 static UniValue setban(const JSONRPCRequest& request)
 {
-    std::string strCommand;
-    if (!request.params[1].isNull())
-        strCommand = request.params[1].get_str();
-    if (request.fHelp || request.params.size() < 2 ||
-        (strCommand != "add" && strCommand != "remove"))
-        throw std::runtime_error(
-            RPCHelpMan{"setban",
+    const RPCHelpMan help{"setban",
                 "\nAttempts to add or remove an IP/Subnet from the banned list.\n",
                 {
                     {"subnet", RPCArg::Type::STR, RPCArg::Optional::NO, "The IP/Subnet (see getpeerinfo for nodes IP) with an optional netmask (default is /32 = single IP)"},
@@ -543,7 +537,13 @@ static UniValue setban(const JSONRPCRequest& request)
                             + HelpExampleCli("setban", "\"192.168.0.0/24\" \"add\"")
                             + HelpExampleRpc("setban", "\"192.168.0.6\", \"add\", 86400")
                 },
-            }.ToString());
+    };
+    std::string strCommand;
+    if (!request.params[1].isNull())
+        strCommand = request.params[1].get_str();
+    if (request.fHelp || !help.IsValidNumArgs(request.params.size()) || (strCommand != "add" && strCommand != "remove")) {
+        throw std::runtime_error(help.ToString());
+    }
     if (!g_banman) {
         throw JSONRPCError(RPC_DATABASE_ERROR, "Error: Ban database not loaded");
     }

test/functional/rpc_getblockstats.py

@@ -178,5 +178,10 @@ class GetblockstatsTest(BitcoinTestFramework):
         assert_raises_rpc_error(-5, 'Block not found', self.nodes[0].getblockstats,
                                 hash_or_height='000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f')
 
+        # Invalid number of args
+        assert_raises_rpc_error(-1, 'getblockstats hash_or_height ( stats )', self.nodes[0].getblockstats, '00', 1, 2)
+        assert_raises_rpc_error(-1, 'getblockstats hash_or_height ( stats )', self.nodes[0].getblockstats)
+
+
 if __name__ == '__main__':
     GetblockstatsTest().main()