Potential crash when calling ITerminalConnection::WriteInput

[j4james]

Windows Terminal version

Commit edfa3ea

Windows build number

10.0.19045.4651

Other Software

No response

Steps to reproduce

1. Patch the DeviceAttributes implementation in adaptDispatch.cpp to respond like this:

   _api.ReturnResponse({L"ABCD", 3});

2. Open a WSL shell in OpenConsole and execute this:

   printf "\e[c"; read
   

3. Note that it successfully responds with ABC.
4. Now try the same thing in a WSL shell from within Windows Terminal.

Expected Behavior

It should also respond successfully with ABC.

Actual Behavior

The terminal crashes.

The ReturnResponse method takes a std::wstring_view, but the Windows Terminal implementation calls ControlCore::_sendInputToConnection, which calls ITerminalConnection::WriteInput, which expects an hstring. When constructing an hstring from a std::wstring_view it's required that the string be null-terminated, otherwise it aborts. And since std::wstring_view is obviously not guaranteed to be null-terminated, this is asking for trouble.

I know the example I've given above is contrived, but that's just because it was the easiest way to demonstrate the problem. There are a number of places in the AdaptDispatch class that are calling ReturnResponse with a fmt::basic_memory_buffer, and that's not guaranteed to be null-terminated. It's just a matter of luck whether that code crashes or not.