critical update for NFT child genesis validation

Author: jcramer

lib/validation.ts

@@ -346,12 +346,13 @@ export class ValidatorType1 {
             if (slpmsg.versionType === 0x41) {
                 // An NFT1 parent should be provided at input index 0,
                 // so we check this first before checking the whole parent DAG
-                const inputTxid = txn.inputs[0].previousTxHash;
-                const inputTxHex = await this.retrieveRawTransaction(inputTxid);
-                const inputTx: Transaction = Transaction.parseFromBuffer(inputTxHex);
+                const inputPrevTxid = txn.inputs[0].previousTxHash;
+                const inputPrevOut = txn.inputs[0].previousTxOutIndex;
+                const inputPrevTxHex = await this.retrieveRawTransaction(inputPrevTxid);
+                const inputPrevTx: Transaction = Transaction.parseFromBuffer(inputPrevTxHex);
                 let inputSlpMsg;
                 try {
-                    inputSlpMsg = Slp.parseSlpOutputScript(inputTx.outputs[0].scriptPubKey);
+                    inputSlpMsg = Slp.parseSlpOutputScript(inputPrevTx.outputs[0].scriptPubKey);
                 } catch (_) {}
                 if (!inputSlpMsg || inputSlpMsg.versionType !== 0x81) {
                     validation.validity = false;
@@ -360,23 +361,38 @@ export class ValidatorType1 {
                     return validation.validity!;
                 }
                 // Check that the there is a burned output >0 in the parent txn SLP message
-                if (inputSlpMsg.transactionType === SlpTransactionType.SEND &&
-                    !inputSlpMsg.sendOutputs![1].gt(0)) {
-                    validation.validity = false;
-                    validation.waiting = false;
-                    validation.invalidReason = "NFT1 child's parent has SLP output that is not greater than zero.";
-                    return validation.validity!;
-                } else if ((inputSlpMsg.transactionType === SlpTransactionType.GENESIS ||
-                            inputSlpMsg.transactionType === SlpTransactionType.MINT) &&
-                            !inputSlpMsg.genesisOrMintQuantity!.gt(0)) {
-                    validation.validity = false;
-                    validation.waiting = false;
-                    validation.invalidReason = "NFT1 child's parent has SLP output that is not greater than zero.";
-                    return validation.validity!;
+                if (inputSlpMsg.transactionType === SlpTransactionType.SEND) {
+                    if (inputPrevOut > inputSlpMsg.sendOutputs!.length - 1) {
+                        validation.validity = false;
+                        validation.waiting = false;
+                        validation.invalidReason = "NFT1 child GENESIS does not have a valid NFT1 parent input.";
+                        return validation.validity!;
+                    }
+                    if (! inputSlpMsg.sendOutputs![inputPrevOut].gt(0)) {
+                        validation.validity = false;
+                        validation.waiting = false;
+                        validation.invalidReason = "NFT1 child's parent has SLP output that is not greater than zero.";
+                        return validation.validity!;
+                    }
+                } else if (inputSlpMsg.transactionType === SlpTransactionType.GENESIS ||
+                            inputSlpMsg.transactionType === SlpTransactionType.MINT) {
+                    if (inputPrevOut !== 1) {
+                        validation.validity = false;
+                        validation.waiting = false;
+                        validation.invalidReason = "NFT1 child GENESIS does not have a valid NFT1 parent input.";
+                        return validation.validity!;
+                    }
+                    if (!inputSlpMsg.genesisOrMintQuantity!.gt(0)) {
+                        validation.validity = false;
+                        validation.waiting = false;
+                        validation.invalidReason = "NFT1 child's parent has SLP output that is not greater than zero.";
+                        return validation.validity!;
+                    }
                 }
+
                 // Continue to check the NFT1 parent DAG
                 const nft_parent_dag_validity = await this.isValidSlpTxid({
-                    txid: inputTxid,
+                    txid: inputPrevTxid,
                     tokenIdFilter: undefined,
                     tokenTypeFilter: 0x81
                 });