Merge #589

589: Handle errors thrown when converting to utf-8 r=D4nte a=D4nte

`bytesToUtf8` replaced a previously used library. The previous library did not throw when failing to decode whereas `bytesToUtf8` does. Need to handle those errors.

Co-authored-by: Franck Royer <franck@status.im>

CHANGELOG.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Fixed
+
+- Handle errors thrown by `bytesToUtf8`.
+
 ## [0.18.0] - 2022-02-24
 
 ### Changed

examples/web-chat/src/Message.ts

@@ -19,11 +19,7 @@ export class Message {
           return new Message(chatMsg, wakuMsg.timestamp);
         }
       } catch (e) {
-        console.error(
+        console.error("Failed to decode chat message", e);
-          "Failed to decode chat message",
-          wakuMsg.payloadAsUtf8,
-          e
-        );
       }
     }
     return;

src/lib/discovery/dns.ts

@@ -79,38 +79,45 @@ export class DnsNodeDiscovery {
     subdomain: string,
     context: SearchContext
   ): Promise<ENR | null> {
-    const entry = await this._getTXTRecord(subdomain, context);
-    context.visits[subdomain] = true;
-
-    let next: string;
-    let branches: string[];
-
-    const entryType = getEntryType(entry);
     try {
-      switch (entryType) {
+      const entry = await this._getTXTRecord(subdomain, context);
-        case ENRTree.ROOT_PREFIX:
+      context.visits[subdomain] = true;
-          next = ENRTree.parseAndVerifyRoot(entry, context.publicKey);
+
-          return await this._search(next, context);
+      let next: string;
-        case ENRTree.BRANCH_PREFIX:
+      let branches: string[];
-          branches = ENRTree.parseBranch(entry);
+
-          next = selectRandomPath(branches, context);
+      const entryType = getEntryType(entry);
-          return await this._search(next, context);
+      try {
-        case ENRTree.RECORD_PREFIX:
+        switch (entryType) {
-          return ENR.decodeTxt(entry);
+          case ENRTree.ROOT_PREFIX:
-        default:
+            next = ENRTree.parseAndVerifyRoot(entry, context.publicKey);
-          return null;
+            return await this._search(next, context);
+          case ENRTree.BRANCH_PREFIX:
+            branches = ENRTree.parseBranch(entry);
+            next = selectRandomPath(branches, context);
+            return await this._search(next, context);
+          case ENRTree.RECORD_PREFIX:
+            return ENR.decodeTxt(entry);
+          default:
+            return null;
+        }
+      } catch (error) {
+        dbg(
+          `Failed to search DNS tree ${entryType} at subdomain ${subdomain}: ${error}`
+        );
+        return null;
       }
     } catch (error) {
-      dbg(
+      dbg(`Failed to retrieve TXT record at subdomain ${subdomain}: ${error}`);
-        `Failed to search DNS tree ${entryType} at subdomain ${subdomain}: ${error}`
-      );
       return null;
     }
   }
 
   /**
    * Retrieves the TXT record stored at a location from either
-   * this DNS tree cache or via DNS query
+   * this DNS tree cache or via DNS query.
+   *
+   * @throws if the TXT Record contains non-UTF-8 values.
    */
   private async _getTXTRecord(
     subdomain: string,

src/lib/discovery/dns_over_https.ts

@@ -31,6 +31,14 @@ export class DnsOverHttps implements DnsClient {
     public endpoints: Endpoints = [cloudflare, google, opendns]
   ) {}
 
+  /**
+   * Resolves a TXT record
+   *
+   * @param domain The domain name
+   *
+   * @throws if the result is provided in byte form which cannot be decoded
+   * to UTF-8
+   */
   async resolveTXT(domain: string): Promise<string[]> {
     const response = await query({
       questions: [{ type: "TXT", name: domain }],

src/lib/enr/enr.ts

@@ -1,4 +1,5 @@
 import * as RLP from "@ethersproject/rlp";
+import debug from "debug";
 import { Multiaddr, protocols } from "multiaddr";
 // eslint-disable-next-line @typescript-eslint/ban-ts-comment
 // @ts-ignore: No types available
@@ -21,6 +22,8 @@ import { decodeMultiaddrs, encodeMultiaddrs } from "./multiaddrs_codec";
 import { ENRKey, ENRValue, NodeId, SequenceNumber } from "./types";
 import * as v4 from "./v4";
 
+const dbg = debug("waku:enr");
+
 export class ENR extends Map<ENRKey, ENRValue> {
   public static readonly RECORD_PREFIX = "enr:";
   public seq: SequenceNumber;
@@ -78,7 +81,11 @@ export class ENR extends Map<ENRKey, ENRValue> {
     }
     const obj: Record<ENRKey, ENRValue> = {};
     for (let i = 0; i < kvs.length; i += 2) {
-      obj[bytesToUtf8(kvs[i])] = kvs[i + 1];
+      try {
+        obj[bytesToUtf8(kvs[i])] = kvs[i + 1];
+      } catch (e) {
+        dbg("Failed to decode ENR key to UTF-8, skipping it", kvs[i], e);
+      }
     }
     const enr = new ENR(obj, BigInt("0x" + bytesToHex(seq)), signature);
 

src/lib/waku_message/index.ts

@@ -256,7 +256,12 @@ export class WakuMessage {
       return "";
     }
 
-    return bytesToUtf8(this.proto.payload);
+    try {
+      return bytesToUtf8(this.proto.payload);
+    } catch (e) {
+      dbg("Could not decode byte as UTF-8", e);
+      return "";
+    }
   }
 
   get payload(): Uint8Array | undefined {