What is the ruling on someone who shaves his companion's hair while he is in a state of ihram, and likewise his companion?

If the shaving (of the head) was for the ritual and at its appointed time, there is no harm, based on the Hadith of Hudaybiyyah. However, if the shaving was before its appointed time, then you have committed a prohibited act and are liable for a fidyah (expiatory ransom), due to the words of Allah the Almighty: "And do not shave your heads until the sacrificial animal reaches its place of sacrifice. And whoever among you is ill or has an ailment of the head (making shaving necessary must offer) a ransom of fasting or charity or sacrifice." This fidyah consists of fasting for three days, or feeding six needy persons, or sacrificing a sheep.