Are there any canonical English <-> Elvish dictionaries, that means with no added material? Some Grammar would also be useful.
I think the best you're going to get are the Ardalambion wordlists. There are words in them that are obtained from compounds and such, but all are marked and their source given. If you're after grammar then (for Quenya) there is the Ardalambion course or Quetin i lambë eldaiva at Parma Tyelpelassiva. Parma Tyelpelassiva also has a Sindarin course. But again, all these sources extrapolated from the source material by necessity. The Ardalambion course does a good job of explaining where everything comes from and notes any ambiguities.
There are some good digital sources, but there is no complete dictionary that you can "hold in your hands"
It's not a great resource for teaching you the grammar rules of any of the languages, but it's probably the most reliable dictionary out there, including all the words that have only come to light in recent posthumous Tolkien publications and properly sourcing everything so that you can see where a word or its gloss came from. Words are also distinguished by the time period in which Tolkien made them, as his languages were constantly evolving throughout his life.
Eldamo's "Academic Word Search" will ignore any neologisms or fan additions people have made to the languages.