From a3b065b51fb333d976108a1fe34b7f663fd67285 Mon Sep 17 00:00:00 2001
From: Anthony Towns <aj@erisian.com.au>
Date: Wed, 27 Jun 2018 17:54:32 +1000
Subject: [PATCH 1/2] Error on missing amount in signrawtransaction*

Signatures using segregated witness commit to the amount being spent,
so that value must be passed into signrawtransactionwithkey and
signrawtransactionwithwallet. This ensures an error is issued if that
doesn't happen, rather than just assuming the value is 0 and producing
a signature that is almost certainly invalid.
---
 src/rpc/rawtransaction.cpp | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/rpc/rawtransaction.cpp b/src/rpc/rawtransaction.cpp
index 3b3f43edea7..f14db086b17 100644
--- a/src/rpc/rawtransaction.cpp
+++ b/src/rpc/rawtransaction.cpp
@@ -811,7 +811,7 @@ UniValue SignTransaction(CMutableTransaction& mtx, const UniValue& prevTxsUnival
                 }
                 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"));
                 }
@@ -884,6 +884,11 @@ UniValue SignTransaction(CMutableTransaction& mtx, const UniValue& prevTxsUnival
 
         UpdateInput(txin, 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) {

From 685d1d8115f61b15115d80523dd8273f0a816534 Mon Sep 17 00:00:00 2001
From: Anthony Towns <aj@erisian.com.au>
Date: Wed, 27 Jun 2018 17:54:42 +1000
Subject: [PATCH 2/2] [tests] Check signrawtransaction* errors on missing
 prevtx info

---
 test/functional/rpc_rawtransaction.py | 55 +++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)

diff --git a/test/functional/rpc_rawtransaction.py b/test/functional/rpc_rawtransaction.py
index 48b4a4a9dbc..2485dcf6ec6 100755
--- a/test/functional/rpc_rawtransaction.py
+++ b/test/functional/rpc_rawtransaction.py
@@ -137,6 +137,61 @@ class RawTransactionsTest(BitcoinTestFramework):
             self.nodes[2].createrawtransaction(inputs=[{'txid': txid, 'vout': 9}], outputs=[{address: 99}, {'data': '99'}, {'data': '99'}]),
         )
 
+        for type in ["bech32", "p2sh-segwit", "legacy"]:
+            addr = self.nodes[0].getnewaddress("", type)
+            addrinfo = self.nodes[0].getaddressinfo(addr)
+            pubkey = addrinfo["scriptPubKey"]
+
+            self.log.info('sendrawtransaction with missing prevtx info (%s)' %(type))
+
+            # Test `signrawtransactionwithwallet` 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].signrawtransactionwithwallet(rawtx, [prevtx])
+            assert succ["complete"]
+            if type == "legacy":
+                del prevtx["amount"]
+                succ = self.nodes[0].signrawtransactionwithwallet(rawtx, [prevtx])
+                assert succ["complete"]
+
+            if type != "legacy":
+                assert_raises_rpc_error(-3, "Missing amount", self.nodes[0].signrawtransactionwithwallet, rawtx, [
+                    {
+                        "txid": txid,
+                        "scriptPubKey": pubkey,
+                        "vout": 3,
+                    }
+                ])
+
+            assert_raises_rpc_error(-3, "Missing vout", self.nodes[0].signrawtransactionwithwallet, rawtx, [
+                {
+                    "txid": txid,
+                    "scriptPubKey": pubkey,
+                    "amount": 1,
+                }
+            ])
+            assert_raises_rpc_error(-3, "Missing txid", self.nodes[0].signrawtransactionwithwallet, rawtx, [
+                {
+                    "scriptPubKey": pubkey,
+                    "vout": 3,
+                    "amount": 1,
+                }
+            ])
+            assert_raises_rpc_error(-3, "Missing scriptPubKey", self.nodes[0].signrawtransactionwithwallet, rawtx, [
+                {
+                    "txid": txid,
+                    "vout": 3,
+                    "amount": 1
+                }
+            ])
+
+        #########################################
+        # sendrawtransaction with missing input #
+        #########################################
+
         self.log.info('sendrawtransaction with missing input')
         inputs  = [ {'txid' : "1d1d4e24ed99057e84c3f80fd8fbec79ed9e1acee37da269356ecea000000000", 'vout' : 1}] #won't exists
         outputs = { self.nodes[0].getnewaddress() : 4.998 }