It seems to be against the rules for the code to be generated by tools which are not widely available. This essentially means that competitors generating code using internal tools or closed beta research models would cross the line. (Employees of certain big companies, watch out!)

OpenAI tools and products are not available in some countries. However, since some sites (incl. Codeforces) might not be available in those countries either, and there is precedent that copying from those sites is allowed, ChatGPT should be clean under current rules.