windows: Use RW/RX permissions for injection

[yjugl]

This makes Frida injection compatible with more software. In particular, Mozilla Firefox rejects thread startup if the start address is RWX.

[oleavr]

Yay, thanks for doing this! 🙌 Will land this as soon as I get the CI back in working order, so we can cut releases once again 😊

[yjugl]

I can reproduce the failure locally and I'm taking a look.

[yjugl]

The issue was that the code below requires (one byte of) the FridaRemoteWorkerContext to be writable:

void
frida_agent_main (const char * data, bool * stay_resident)
{
  (void) data;

  *stay_resident = true;

  append_to_log ('m');
}

I changed my patch to put the code and the FridaRemoteWorkerContext on different memory pages, so that they can have different permissions. This seemed like the easiest option. Alternatively we could probably make FridaRemoteWorkerContext readonly if we remove the stay_resident field. But then we would need to propagate that information in a different way, e.g. with the thread exit code or with a Windows event object.

[oleavr]

Thanks! 🔥