From d302119ffbca66505f208b161c15ba1e2adf4f94 Mon Sep 17 00:00:00 2001
From: Simon Warta <simon@warta.it>
Date: Tue, 11 Jan 2022 22:44:04 +0100
Subject: [PATCH] Implement more advanced address checks

---
 components/forms/TransactionForm.js | 36 +++++++++++++++--------------
 lib/displayHelpers.js               | 29 ++++++++++++++++++++++-
 2 files changed, 47 insertions(+), 18 deletions(-)

diff --git a/components/forms/TransactionForm.js b/components/forms/TransactionForm.js
index 54de8dd..5ed86be 100644
--- a/components/forms/TransactionForm.js
+++ b/components/forms/TransactionForm.js
@@ -7,7 +7,7 @@ import { withRouter } from "next/router";
 import Button from "../../components/inputs/Button";
 import Input from "../../components/inputs/Input";
 import StackableContainer from "../layout/StackableContainer";
-import { exampleAddress } from "../../lib/displayHelpers";
+import { checkAddress, exampleAddress } from "../../lib/displayHelpers";
 
 class TransactionForm extends React.Component {
   constructor(props) {
@@ -56,23 +56,25 @@ class TransactionForm extends React.Component {
   };
 
   handleCreate = async () => {
-    if (this.state.toAddress.length === 45) {
-      this.setState({ processing: true });
-      const tx = this.createTransaction(
-        this.state.toAddress,
-        this.state.amount,
-        this.state.gas
-      );
-      console.log(tx);
-      const dataJSON = JSON.stringify(tx);
-      const res = await axios.post("/api/transaction", { dataJSON });
-      const { transactionID } = res.data;
-      this.props.router.push(
-        `${this.props.address}/transaction/${transactionID}`
-      );
-    } else {
-      this.setState({ addressError: "Use a valid cosmos-hub address" });
+    const addressError = checkAddress(this.state.toAddress);
+    if (addressError) {
+      this.setState({ addressError: `Invalid address for network ${process.env.NEXT_PUBLIC_CHAIN_ID}: ${addressError}` });
+      return;
     }
+
+    this.setState({ processing: true });
+    const tx = this.createTransaction(
+      this.state.toAddress,
+      this.state.amount,
+      this.state.gas
+    );
+    console.log(tx);
+    const dataJSON = JSON.stringify(tx);
+    const res = await axios.post("/api/transaction", { dataJSON });
+    const { transactionID } = res.data;
+    this.props.router.push(
+      `${this.props.address}/transaction/${transactionID}`
+    );
   };
 
   render() {
diff --git a/lib/displayHelpers.js b/lib/displayHelpers.js
index f5706da..284a281 100644
--- a/lib/displayHelpers.js
+++ b/lib/displayHelpers.js
@@ -91,4 +91,31 @@ const examplePubkey = (index) => {
   return toBase64(data);
 }
 
-export { abbreviateLongString, printableCoin, printableCoins, exampleAddress, examplePubkey };
+/**
+ * Returns an error message for invalid addresses.
+ * 
+ * Returns null of there is no error.
+ */
+const checkAddress = (input) => {
+  if (!input) return "Empty";
+
+  let data;
+  let prefix;
+  try {
+     ({ data, prefix } = Bech32.decode(input));
+  } catch (error) {
+    return error.toString();
+  }
+
+  if (prefix !== process.env.NEXT_PUBLIC_ADDRESS_PREFIX) {
+    return `Expected address prefix '${process.env.NEXT_PUBLIC_ADDRESS_PREFIX}' but got '${prefix}'`;
+  }
+
+  if (data.length !== 20) {
+    return "Invalid address length in bech32 data. Must be 20 bytes.";
+  }
+
+  return null;
+}
+
+export { abbreviateLongString, printableCoin, printableCoins, exampleAddress, examplePubkey, checkAddress };