The situation is somewhat tricky, but unless you plan on selling ripping software, it does not conflict with the law:
"In her ruling, Judge Marilyn Hall Patel said that the complex meant that it was not illegal for consumers to copy their own DVDs – just illegal to produce a program that allowed them to do so.
"While it may well be fair use for an individual consumer to store a backup copy of a personally-owned DVD on that individual's computer, a federal law has nonetheless made it illegal to manufacture or traffic in a device or tool that permits a consumer to make such copies.""
So we end up in a situation, where it is illegal to produce said program, but we can buy and use it legally.
http://www.guardian.co.uk/technology/2009/aug/12/real-realdvd
The above case is from the US. Germany has similar laws, where they only make it illegal to circumvent "effective" copy-protection methods. However, the copy-protection methods used for DVD's are already widely known and can be easily circumvented, so they don't count as effective methods, which makes it legal to rip DVD's with said copy-protection.
The UK does seem to be an exception in this regard.