According to [Space Exploration and Humanity: A Historical Encyclopedia][1]:

> During Vostok, Voskhod, and Soyuz flights, urine and feces were entrained in an air stream and collected for disposal at the end of the mission

[Spaceflight Life Support and Biospherics][2] makes the same claim.

This suggests there was a form of space toilet aboard or at least a pneumatic collection hose. No other details seem to appear in those books, unfortunately. 


  [1]: https://books.google.com/books?id=2ZNxDwAAQBAJ&pg=PA558&lpg=PA558&dq=vostok%20urine%20entrained%20air%20stream&source=bl&ots=zxiI3VXLa8&sig=ACfU3U0p4PiKCQYgXJgRoBSZs5eD98hUhw&hl=en&sa=X&ved=2ahUKEwjsnLGx56nqAhVGnJ4KHWllBsMQ6AEwB3oECAsQAQ#v=onepage&q=vostok%20urine%20entrained%20air%20stream&f=false
  [2]: https://books.google.com/books?id=y3zoCAAAQBAJ&pg=PA139&lpg=PA139&dq=vostok%20urine%20collection&source=bl&ots=gpBYWZxA50&sig=ACfU3U0y5xkOyvCTiRTQfuftFaqwvt5Tog&hl=en&sa=X&ved=2ahUKEwjFsez75qnqAhVP_J4KHdIrAogQ6AEwAHoECAoQAQ#v=onepage&q=vostok%20urine%20collection&f=false