Merge #13796: [0.16] Make signrawtransaction give an error when amount is needed but missing

212ef1f954 [tests] Check signrawtransaction* errors on missing prevtx info (Anthony Towns)
1825e37075 Error on missing amount in signrawtransaction* (Anthony Towns)

Pull request description:

  Backport of #13547 to 0.16

Tree-SHA512: 7a660023b6948632a1f949443c18fa45add75ec8c36df1ebbaccd181dd1560c1bef460f061f8dab36b6a5df295eb4967effaa2cf55ea06b41d8f7562842a39ec

src/rpc/rawtransaction.cpp

@@ -830,7 +830,7 @@ UniValue signrawtransaction(const JSONRPCRequest& request)
                 }
                 Coin newcoin;
                 newcoin.out.scriptPubKey = scriptPubKey;
-                newcoin.out.nValue = 0;
+                newcoin.out.nValue = MAX_MONEY;
                 if (prevOut.exists("amount")) {
                     newcoin.out.nValue = AmountFromValue(find_value(prevOut, "amount"));
                 }
@@ -910,6 +910,11 @@ UniValue signrawtransaction(const JSONRPCRequest& request)
 
         UpdateTransaction(mtx, i, sigdata);
 
+        // amount must be specified for valid segwit signature
+        if (amount == MAX_MONEY && !txin.scriptWitness.IsNull()) {
+            throw JSONRPCError(RPC_TYPE_ERROR, strprintf("Missing amount for %s", coin.out.ToString()));
+        }
+
         ScriptError serror = SCRIPT_ERR_OK;
         if (!VerifyScript(txin.scriptSig, prevPubKey, &txin.scriptWitness, STANDARD_SCRIPT_VERIFY_FLAGS, TransactionSignatureChecker(&txConst, i, amount), &serror)) {
             if (serror == SCRIPT_ERR_INVALID_STACK_OPERATION) {

test/functional/rpc_rawtransaction.py

@@ -98,6 +98,57 @@ class RawTransactionsTest(BitcoinTestFramework):
         # Test `createrawtransaction` invalid `replaceable`
         assert_raises_rpc_error(-3, "Expected type bool", self.nodes[0].createrawtransaction, [], {}, 0, 'foo')
 
+        for type in ["bech32", "p2sh-segwit", "legacy"]:
+            addr = self.nodes[0].getnewaddress("", type)
+            addrinfo = self.nodes[0].validateaddress(addr)
+            pubkey = addrinfo["scriptPubKey"]
+
+            self.log.info('sendrawtransaction with missing prevtx info (%s)' %(type))
+
+            # Test `signrawtransaction` invalid `prevtxs`
+            inputs  = [ {'txid' : txid, 'vout' : 3, 'sequence' : 1000}]
+            outputs = { self.nodes[0].getnewaddress() : 1 }
+            rawtx   = self.nodes[0].createrawtransaction(inputs, outputs)
+
+            prevtx = dict(txid=txid, scriptPubKey=pubkey, vout=3, amount=1)
+            succ = self.nodes[0].signrawtransaction(rawtx, [prevtx])
+            assert succ["complete"]
+            if type == "legacy":
+                del prevtx["amount"]
+                succ = self.nodes[0].signrawtransaction(rawtx, [prevtx])
+                assert succ["complete"]
+
+            if type != "legacy":
+                assert_raises_rpc_error(-3, "Missing amount", self.nodes[0].signrawtransaction, rawtx, [
+                    {
+                        "txid": txid,
+                        "scriptPubKey": pubkey,
+                        "vout": 3,
+                    }
+                ])
+
+            assert_raises_rpc_error(-3, "Missing vout", self.nodes[0].signrawtransaction, rawtx, [
+                {
+                    "txid": txid,
+                    "scriptPubKey": pubkey,
+                    "amount": 1,
+                }
+            ])
+            assert_raises_rpc_error(-3, "Missing txid", self.nodes[0].signrawtransaction, rawtx, [
+                {
+                    "scriptPubKey": pubkey,
+                    "vout": 3,
+                    "amount": 1,
+                }
+            ])
+            assert_raises_rpc_error(-3, "Missing scriptPubKey", self.nodes[0].signrawtransaction, rawtx, [
+                {
+                    "txid": txid,
+                    "vout": 3,
+                    "amount": 1
+                }
+            ])
+
         #########################################
         # sendrawtransaction with missing input #
         #########################################