I assume you are a Polish Erasmus student in Malaga? If so, it is important how long you have been staying in Spain when you are travelling with InterRail. If you will be less than six months in Spain at Christmas, you can buy a "Polish InterRail pass" and travel with it from Malaga until the Polish border. If you have been staying more than six months in Spain you will need to get a "Spanish InterRail pass" which you can use from the Spanish border until Warszawa.
On each "mission section" you would get a discounted ticket as InterRail isnt valid in your country of residence.
OK, so here's a possible connection (note that the current timetable is only valid till mid-december so I picked a random date within this period):
Malaga 1205 - 1440 Madrid Puerta de Atocha
AVE, 10€ reservation
Madrid Chamartin 1615 - 2203 Hendaye
Alaris, 6,50€ reservation
Hendaye 2218 - 0711 Paris Austerlitz
Paris Est 0909 - 1258 Frankfurt/M Hbf
TGV, 10€ reservation
Frankfurt/M Hbf 1416 - 2122 Wien West
ICE, no reservation required
2208 Wien West - Warszawa Centralna 0710 vienna-warsaw-night-train-t1544.html
Best solution (with InterRail) would be the 5in10 flexi pass for 159€, plus the above mentioned reservation fees in each direction. Alternative connections are available as well, but they are likely to take more time/more money for reservations. If you dont want to spend much money on reservations, prepare for a much longer journey.
You can have a look for travel times yourself aswell: http://www.raildude.com/en/interrail-tr ... tions.html