On Mon, Dec 11, 2023 at 09:35:37PM -0800, Christoph Hellwig wrote: > On Mon, Dec 11, 2023 at 02:19:26PM -0800, Darrick J. Wong wrote: > > block/char/special files... I guess those can just turn into zero length > > regular files. > > Ys, and I don't think that is much of a problem. > > > Would this NAK remain even if there were external corroborating > > evidence? > > > > For example, what if we read the dirents out of the first directory > > block, seek out parent pointers in the alleged children, and confirm a > > 1:1 match between the alleged dirents and pptrs? Unprivileged userspace > > can certain create a regular file N that looks like a dirent block, but > > it cannot create dangling pptrs back to N to trick the verification > > algorithm. > > That does look like I a good enough evinde as you said userspace can't > fake up the parent pointer. Yeah, and for non-dirs, we /could/ just scan all the directory entries to see if we come up with any hits for the inode whose mode we do not know; the ftype will help us set that back. --D
