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url: fix array overrun in node:url::SetArgs() #47001

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merged 1 commit into from
Mar 10, 2023
Merged

url: fix array overrun in node:url::SetArgs() #47001

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58 changes: 17 additions & 41 deletions src/node_url.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -20,7 +20,6 @@ using v8::Local;
using v8::NewStringType;
using v8::Object;
using v8::String;
using v8::Undefined;
using v8::Value;

Local<String> Utf8String(Isolate* isolate, const std::string& str) {
Expand All @@ -46,18 +45,20 @@ enum url_update_action {
kHref = 9,
};

void SetArgs(Environment* env, Local<Value> argv[10], const ada::result& url) {
void SetArgs(Environment* env,
Local<Value> (*argv)[10],
const ada::result& url) {
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Ideally this parameter should be an const ada::url&. It doesn't make sense to pass an ada::result in when we always expect it to be filled with the "valid" value.

In fact the call sites should probably change from this:

  ada::result out = ada::parse(input.ToStringView());
  CHECK(out);
  out->set_protocol(…);

to

  ada::result out = ada::parse(input.ToStringView());
  CHECK(out);
  const ada::url& url = out.value();
  url.set_protocol(…);

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out.value() returns a copy. The current implementation looks unsafe, but CHECK(out) ensures that it is not. I tried to avoid returning a copy. @lemire wrote about this on Ada's discussion board: ada-url/ada#200

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I think you misunderstood ada-url/ada#200. out.value() (and equivalently *out) does not return a copy by itself. It returns a reference, so if you put it into a const ada::url& then no copies are made.

On the other hand, ada::url url = *out, which would make a copy. That's not what I'm suggesting here.

Alternatively, you can also do

  ada::result out = ada::parse(input.ToStringView());
  CHECK(out);
  ada::url url = std::move(*out);

which is written under the "performance tip". It would also avoid a copy.

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It is likely that the current code is safe and efficient. I think we are discussing 'coding style' which is subjective.

I don't personally find the url->... annoying.

I am slightly triggered by the (*argv)[..] however. :-)

What about using a reference to an array instead?

Local<Value> (&argv)[10]

(The ampersand would be dropped from the calling site.)

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It's a style guide thing: pointers for things that are mutated, const references otherwise.

With mutable references it's sometimes ambiguous to a reader if code operates on the original or on a copy. With pointers, no such ambiguity exists.

Isolate* isolate = env->isolate();
argv[0] = Utf8String(isolate, url->get_href());
argv[1] = Utf8String(isolate, url->get_origin());
argv[2] = Utf8String(isolate, url->get_protocol());
argv[3] = Utf8String(isolate, url->get_hostname());
argv[4] = Utf8String(isolate, url->get_pathname());
argv[5] = Utf8String(isolate, url->get_search());
argv[6] = Utf8String(isolate, url->get_username());
argv[7] = Utf8String(isolate, url->get_password());
argv[8] = Utf8String(isolate, url->get_port());
argv[9] = Utf8String(isolate, url->get_hash());
(*argv)[0] = Utf8String(isolate, url->get_href());
(*argv)[1] = Utf8String(isolate, url->get_origin());
(*argv)[2] = Utf8String(isolate, url->get_protocol());
(*argv)[3] = Utf8String(isolate, url->get_hostname());
(*argv)[4] = Utf8String(isolate, url->get_pathname());
(*argv)[5] = Utf8String(isolate, url->get_search());
(*argv)[6] = Utf8String(isolate, url->get_username());
(*argv)[7] = Utf8String(isolate, url->get_password());
(*argv)[8] = Utf8String(isolate, url->get_port());
(*argv)[9] = Utf8String(isolate, url->get_hash());
}

void Parse(const FunctionCallbackInfo<Value>& args) {
Expand All @@ -69,7 +70,6 @@ void Parse(const FunctionCallbackInfo<Value>& args) {
Local<Function> success_callback_ = args[2].As<Function>();

Environment* env = Environment::GetCurrent(args);
Isolate* isolate = env->isolate();
HandleScope handle_scope(env->isolate());
Context::Scope context_scope(env->context());

Expand All @@ -89,20 +89,8 @@ void Parse(const FunctionCallbackInfo<Value>& args) {
return args.GetReturnValue().Set(false);
}

const Local<Value> undef = Undefined(isolate);
Local<Value> argv[] = {
undef,
undef,
undef,
undef,
undef,
undef,
undef,
undef,
undef,
undef,
};
SetArgs(env, argv, out);
Local<Value> argv[10];
SetArgs(env, &argv, out);
USE(success_callback_->Call(
env->context(), args.This(), arraysize(argv), argv));
args.GetReturnValue().Set(true);
Expand Down Expand Up @@ -235,20 +223,8 @@ void UpdateUrl(const FunctionCallbackInfo<Value>& args) {
}
}

const Local<Value> undef = Undefined(isolate);
Local<Value> argv[] = {
undef,
undef,
undef,
undef,
undef,
undef,
undef,
undef,
undef,
undef,
};
SetArgs(env, argv, out);
Local<Value> argv[10];
SetArgs(env, &argv, out);
USE(success_callback_->Call(
env->context(), args.This(), arraysize(argv), argv));
args.GetReturnValue().Set(result);
Expand Down