On Sun, Jan 28, 2018 at 10:39:10PM -0500, Mimi Zohar wrote: > At what point is the signature on the Merkle tree hash verified? I > can't imagine it being done every time a page is read. It must be > done and the result cached at file open. Sorry, I misread your question. The signature on the Merkle tree hash is verified the file is opened, and then validated Merkle tree hash is cached in the in-memory inode data structure. This is similar to how we cache the per-file key in fscrypt; once the key is derived, we keep it in the inode cache until the inode is dropped from the inode cache, or after a userspace request to revoke all keys derived from a user's login key (which is triggered when the user logs out of their ChromeOS session). - Ted
