net: add support for resolving DNS CAA records

This adds support for DNS Certification Authority Authorization
(RFC 8659) to Node.js.

PR-URL: https://github.com/nodejs/node/pull/35466
Fixes: https://github.com/nodejs/node/issues/19239
Refs: https://github.com/nodejs/node/issues/14713
Reviewed-By: Anna Henningsen <anna@addaleax.net>

1 files changed, 79 insertions, 0 deletions

diff --git a/src/cares_wrap.cc b/src/cares_wrap.cc
index cc7ad316d2b..fcffc2bec67 100644
--- a/src/cares_wrap.cc
+++ b/src/cares_wrap.cc
@@ -50,6 +50,10 @@
 # include <arpa/nameser.h>
 #endif
 
+#ifndef T_CAA
+#  define T_CAA    257 /* Certification Authority Authorization */
+#endif
+
 #if defined(__OpenBSD__)
 # define AI_V4MAPPED 0
 #endif
@@ -882,6 +886,43 @@ int ParseMxReply(Environment* env,
   return ARES_SUCCESS;
 }
 
+int ParseCaaReply(Environment* env,
+                  const unsigned char* buf,
+                  int len,
+                  Local<Array> ret,
+                  bool need_type = false) {
+  HandleScope handle_scope(env->isolate());
+  auto context = env->context();
+
+  struct ares_caa_reply* caa_start;
+  int status = ares_parse_caa_reply(buf, len, &caa_start);
+  if (status != ARES_SUCCESS) {
+    return status;
+  }
+
+  uint32_t offset = ret->Length();
+  ares_caa_reply* current = caa_start;
+  for (uint32_t i = 0; current != nullptr; ++i, current = current->next) {
+    Local<Object> caa_record = Object::New(env->isolate());
+
+    caa_record->Set(context,
+                    env->dns_critical_string(),
+                    Integer::New(env->isolate(), current->critical)).Check();
+    caa_record->Set(context,
+                    OneByteString(env->isolate(), current->property),
+                    OneByteString(env->isolate(), current->value)).Check();
+    if (need_type)
+      caa_record->Set(context,
+                      env->type_string(),
+                      env->dns_caa_string()).Check();
+
+    ret->Set(context, i + offset, caa_record).Check();
+  }
+
+  ares_free_data(caa_start);
+  return ARES_SUCCESS;
+}
+
 int ParseTxtReply(Environment* env,
                   const unsigned char* buf,
                   int len,
@@ -1345,6 +1386,13 @@ class QueryAnyWrap: public QueryWrap {
     if (!soa_record.IsEmpty())
       ret->Set(context, ret->Length(), soa_record).Check();
 
+    /* Parse CAA records */
+    status = ParseCaaReply(env(), buf, len, ret, true);
+    if (status != ARES_SUCCESS && status != ARES_ENODATA) {
+      ParseError(status);
+      return;
+    }
+
     CallOnComplete(ret);
   }
 };
@@ -1441,6 +1489,36 @@ class QueryAaaaWrap: public QueryWrap {
   }
 };
 
+class QueryCaaWrap: public QueryWrap {
+ public:
+  QueryCaaWrap(ChannelWrap* channel, Local<Object> req_wrap_obj)
+      : QueryWrap(channel, req_wrap_obj, "resolve6") {
+  }
+
+  int Send(const char* name) override {
+    AresQuery(name, ns_c_in, T_CAA);
+    return 0;
+  }
+
+  SET_NO_MEMORY_INFO()
+  SET_MEMORY_INFO_NAME(QueryAaaaWrap)
+  SET_SELF_SIZE(QueryAaaaWrap)
+
+ protected:
+  void Parse(unsigned char* buf, int len) override {
+    HandleScope handle_scope(env()->isolate());
+    Context::Scope context_scope(env()->context());
+
+    Local<Array> ret = Array::New(env()->isolate());
+    int status = ParseCaaReply(env(), buf, len, ret);
+    if (status != ARES_SUCCESS) {
+      ParseError(status);
+      return;
+    }
+
+    this->CallOnComplete(ret);
+  }
+};
 
 class QueryCnameWrap: public QueryWrap {
  public:
@@ -2238,6 +2316,7 @@ void Initialize(Local<Object> target,
   env->SetProtoMethod(channel_wrap, "queryAny", Query<QueryAnyWrap>);
   env->SetProtoMethod(channel_wrap, "queryA", Query<QueryAWrap>);
   env->SetProtoMethod(channel_wrap, "queryAaaa", Query<QueryAaaaWrap>);
+  env->SetProtoMethod(channel_wrap, "queryCaa", Query<QueryCaaWrap>);
   env->SetProtoMethod(channel_wrap, "queryCname", Query<QueryCnameWrap>);
   env->SetProtoMethod(channel_wrap, "queryMx", Query<QueryMxWrap>);
   env->SetProtoMethod(channel_wrap, "queryNs", Query<QueryNsWrap>);