Marriages between Muslims and non Muslims is prohibited under Islamic law, except in certain limited circumstances. Malaysian Islamic law is even more limited than some other schools of Islamic law. International human rights norms however suggest that the prohibition and criminalisation of interfaith marriage is an unreasonable restriction on the rights of men and women to marry and found a family.
Under Islamic law, as I understand it, a Muslim woman can only marry a Muslim man. However, a Muslim man can marry a Muslim woman or a Kitabiyyah. See for example section 10 of the Islamic Family Law (Federal Territories) Act 1984:-