permission,dns: add permission for dns

Author: theanarkh

doc/api/cli.md

@@ -357,6 +357,48 @@ Error: Access to this API has been restricted
 }
 ```
 
+### `--allow-net-dns`
+
+<!-- YAML
+added: REPLACEME
+-->
+
+> Stability: 1.1 - Active development
+
+When using the [Permission Model][], the process will not be able to make dns query
+by default.
+Attempts to do so will throw an `ERR_ACCESS_DENIED` unless the
+user explicitly passes the `--allow-net-dns` flag when starting Node.js.
+
+Example:
+
+```js
+const dns = require('node:dns');
+dns.lookup("localhost", () => {});
+```
+
+```console
+$ node --experimental-permission --allow-fs-read=\* index.js
+node:dns:235
+  const err = cares.getaddrinfo(
+                    ^
+
+Error: Access to this API has been restricted
+    at Object.lookup (node:dns:235:21)
+    at Object.<anonymous> (/home/index.js:2:5)
+    at Module._compile (node:internal/modules/cjs/loader:1460:14)
+    at Module._extensions..js (node:internal/modules/cjs/loader:1544:10)
+    at Module.load (node:internal/modules/cjs/loader:1275:32)
+    at Module._load (node:internal/modules/cjs/loader:1091:12)
+    at wrapModuleLoad (node:internal/modules/cjs/loader:212:19)
+    at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:158:5)
+    at node:internal/main/run_main_module:30:49 {
+  code: 'ERR_ACCESS_DENIED',
+  permission: 'NetDNS',
+  resource: 'lookup'
+}
+```
+
 ### `--build-snapshot`
 
 <!-- YAML

doc/api/permissions.md

@@ -575,6 +575,7 @@ There are constraints you need to know before using this system:
   * Inspector protocol
   * File system access
   * WASI
+  * DNS
 * The Permission Model is initialized after the Node.js environment is set up.
   However, certain flags such as `--env-file` or `--openssl-config` are designed
   to read files before environment initialization. As a result, such flags are

node.gyp

@@ -155,6 +155,7 @@
       'src/permission/permission.cc',
       'src/permission/wasi_permission.cc',
       'src/permission/worker_permission.cc',
+      'src/permission/net_dns_permission.cc',
       'src/pipe_wrap.cc',
       'src/process_wrap.cc',
       'src/signal_wrap.cc',

src/cares_wrap.cc

@@ -1417,6 +1417,8 @@ static void Query(const FunctionCallbackInfo<Value>& args) {
   node::Utf8Value utf8name(env->isolate(), string);
   auto plain_name = utf8name.ToStringView();
   std::string name = ada::idna::to_ascii(plain_name);
+  THROW_IF_INSUFFICIENT_PERMISSIONS(
+      env, permission::PermissionScope::kNetDNS, name);
   channel->ModifyActivityQueryCount(1);
   int err = wrap->Send(name.c_str());
   if (err) {
@@ -1429,7 +1431,6 @@ static void Query(const FunctionCallbackInfo<Value>& args) {
   args.GetReturnValue().Set(err);
 }
 
-
 void AfterGetAddrInfo(uv_getaddrinfo_t* req, int status, struct addrinfo* res) {
   auto cleanup = OnScopeLeave([&]() { uv_freeaddrinfo(res); });
   BaseObjectPtr<GetAddrInfoReqWrap> req_wrap{
@@ -1568,15 +1569,15 @@ void CanonicalizeIP(const FunctionCallbackInfo<Value>& args) {
 
 void GetAddrInfo(const FunctionCallbackInfo<Value>& args) {
   Environment* env = Environment::GetCurrent(args);
-
   CHECK(args[0]->IsObject());
   CHECK(args[1]->IsString());
   CHECK(args[2]->IsInt32());
   CHECK(args[4]->IsUint32());
   Local<Object> req_wrap_obj = args[0].As<Object>();
   node::Utf8Value hostname(env->isolate(), args[1]);
   std::string ascii_hostname = ada::idna::to_ascii(hostname.ToStringView());
-
+  THROW_IF_INSUFFICIENT_PERMISSIONS(
+      env, permission::PermissionScope::kNetDNS, ascii_hostname);
   int32_t flags = 0;
   if (args[3]->IsInt32()) {
     flags = args[3].As<Int32>()->Value();
@@ -1639,7 +1640,9 @@ void GetNameInfo(const FunctionCallbackInfo<Value>& args) {
   node::Utf8Value ip(env->isolate(), args[1]);
   const unsigned port = args[2]->Uint32Value(env->context()).FromJust();
   struct sockaddr_storage addr;
-
+  THROW_IF_INSUFFICIENT_PERMISSIONS(
+      env, permission::PermissionScope::kNetDNS,
+      (*ip + std::string(":") + std::to_string(port)));
   CHECK(uv_ip4_addr(*ip, port, reinterpret_cast<sockaddr_in*>(&addr)) == 0 ||
         uv_ip6_addr(*ip, port, reinterpret_cast<sockaddr_in6*>(&addr)) == 0);
 

src/env.cc

@@ -936,6 +936,11 @@ Environment::Environment(IsolateData* isolate_data,
                           options_->allow_fs_write,
                           permission::PermissionScope::kFileSystemWrite);
     }
+    if (!options_->allow_net_dns) {
+      permission()->Apply(this,
+                          {"*"},
+                          permission::PermissionScope::kNetDNS);
+    }
   }
 }
 

src/node_options.cc

@@ -464,6 +464,10 @@ EnvironmentOptionsParser::EnvironmentOptionsParser() {
             "allow worker threads when any permissions are set",
             &EnvironmentOptions::allow_worker_threads,
             kAllowedInEnvvar);
+  AddOption("--allow-net-dns",
+            "allow dns when any permissions are set",
+            &EnvironmentOptions::allow_net_dns,
+            kAllowedInEnvvar);
   AddOption("--experimental-repl-await",
             "experimental await keyword support in REPL",
             &EnvironmentOptions::experimental_repl_await,

src/node_options.h

@@ -132,6 +132,7 @@ class EnvironmentOptions : public Options {
   bool allow_child_process = false;
   bool allow_wasi = false;
   bool allow_worker_threads = false;
+  bool allow_net_dns = false;
   bool experimental_repl_await = true;
   bool experimental_vm_modules = false;
   bool expose_internals = false;

src/permission/net_dns_permission.cc

@@ -0,0 +1,23 @@
+#include "net_dns_permission.h"
+
+#include <string>
+#include <vector>
+
+namespace node {
+
+namespace permission {
+
+void NetDNSPermission::Apply(Environment* env,
+                             const std::vector<std::string>& allow,
+                             PermissionScope scope) {
+  deny_all_ = true;
+}
+
+bool NetDNSPermission::is_granted(Environment* env,
+                                  PermissionScope perm,
+                                  const std::string_view& param) const {
+  return deny_all_ == false;
+}
+
+}  // namespace permission
+}  // namespace node

src/permission/net_dns_permission.h

@@ -0,0 +1,32 @@
+#ifndef SRC_PERMISSION_NET_DNS_PERMISSION_H_
+#define SRC_PERMISSION_NET_DNS_PERMISSION_H_
+
+#if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
+
+#include <vector>
+#include "permission/permission_base.h"
+
+
+namespace node {
+
+namespace permission {
+
+class NetDNSPermission final : public PermissionBase {
+ public:
+  void Apply(Environment* env,
+             const std::vector<std::string>& allow,
+             PermissionScope scope) override;
+  bool is_granted(Environment* env,
+                  PermissionScope perm,
+                  const std::string_view& param = "") const override;
+
+ private:
+  bool deny_all_;
+};
+
+}  // namespace permission
+
+}  // namespace node
+
+#endif  // defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
+#endif  // SRC_PERMISSION_NET_DNS_PERMISSION_H_

src/permission/permission.cc

@@ -83,6 +83,7 @@ Permission::Permission() : enabled_(false) {
   std::shared_ptr<PermissionBase> inspector =
       std::make_shared<InspectorPermission>();
   std::shared_ptr<PermissionBase> wasi = std::make_shared<WASIPermission>();
+  std::shared_ptr<PermissionBase> dns = std::make_shared<NetDNSPermission>();
 #define V(Name, _, __)                                                         \
   nodes_.insert(std::make_pair(PermissionScope::k##Name, fs));
   FILESYSTEM_PERMISSIONS(V)
@@ -103,6 +104,10 @@ Permission::Permission() : enabled_(false) {
   nodes_.insert(std::make_pair(PermissionScope::k##Name, wasi));
   WASI_PERMISSIONS(V)
 #undef V
+#define V(Name, _, __)                                                         \
+  nodes_.insert(std::make_pair(PermissionScope::k##Name, dns));
+  NET_DNS_PERMISSIONS(V)
+#undef V
 }
 
 Local<Value> CreateAccessDeniedError(Environment* env,