I need some information. I intend to travel to Canada from 13-29 October. I am a Pakistani national and I am traveling from Germany to Calgary by KLM Airlines. My passport validity is until 12 January and my visa validity is until 11th January. Can I travel with my existing passport or should I renew my passport?
You will be fine.
According to this website of the Government of Canada, if your passport expires before the end of your intended visit, the immigration officer can limit the length of your permitted stay to the length of your passport validity. You're leaving before your passport expires, so you'll be fine.
The "expiry" date of your visa is the last day you may arrive; it isn't actually your maximum visit end date. But if you came on January 11, you'd be turned around since your passport would expire that night.