dns: fix TTL value for AAAA replies to resolveAny()

We were previously reading from the wrong offset, namely the one into the final results array, not the one for the AAAA results itself, which could have lead to reading uninitialized or out-of-bounds data. Also, adjust the test accordingly; TTL values are not modified by c-ares, but are only exposed for a subset of all DNS record types. PR-URL: #25187 Reviewed-By: Luigi Pinca <luigipinca@gmail.com> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Khaidi Chu <i@2333.moe> Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl> Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>

Author: addaleax

src/cares_wrap.cc

@@ -1263,14 +1263,16 @@ class QueryAnyWrap: public QueryWrap {
  }
 
  CHECK_EQ(aaaa_count, naddr6ttls);
+ CHECK_EQ(ret->Length(), a_count + aaaa_count);
  for (uint32_t i = a_count; i < ret->Length(); i++) {
  Local<Object> obj = Object::New(env()->isolate());
  obj->Set(context,
  env()->address_string(),
  ret->Get(context, i).ToLocalChecked()).FromJust();
  obj->Set(context,
  env()->ttl_string(),
- Integer::New(env()->isolate(), addr6ttls[i].ttl)).FromJust();
+ Integer::New(env()->isolate(), addr6ttls[i - a_count].ttl))
+ .FromJust();
  obj->Set(context,
  env()->type_string(),
  env()->dns_aaaa_string()).FromJust();

test/parallel/test-dns-resolveany.js

@@ -53,8 +53,13 @@ server.bind(0, common.mustCall(async () => {
 }));
 
 function validateResults(res) {
- // Compare copies with ttl removed, c-ares fiddles with that value.
- assert.deepStrictEqual(
- res.map((r) => Object.assign({}, r, { ttl: null })),
- answers.map((r) => Object.assign({}, r, { ttl: null })));
+ // TTL values are only provided for A and AAAA entries.
+ assert.deepStrictEqual(res.map(maybeRedactTTL), answers.map(maybeRedactTTL));
+}
+
+function maybeRedactTTL(r) {
+ const ret = { ...r };
+ if (!['A', 'AAAA'].includes(r.type))
+ delete ret.ttl;
+ return ret;
 }