Before taking any legal action, why don't you walk across to your Boss and the company HR and have a word with them, that its more than 7 months and you are waiting for the confirmation letter.
It may have happened that there was a lapse and they missed out on your name, and as you also never mentioned them, they are under the presumption that all is well.
Have a Dialogue first, then deceide if you want to take a legal action or no.
Since you have completed six months probation period, they have not asked you to leave the company on completion of the period. So, You are certainly in the good books, might be your immediate senior or the place you are working might have received the confirmation order and forgotten to hand over to you, you department might have misplaced the order, so there is every possibility of taking the issue on either way, first stop panicking, get yourself clear and enquire the issue...best of luck ...and Shri Ashutosh Thakre clearly given you the right way of approach ....
What rights do you have ?
It's the company's choice whether to confirm you. Until the confirmation is given in writing you are on probation, unless your standing orders says otherwise.
Instead just go and ask your manager why you didn't get a confirmation letter when all others got it and whether there is an issue