On Fri, Jun 01, 2018 at 07:02:20PM +0200, Miklos Szeredi wrote: > On Fri, Jun 1, 2018 at 6:08 PM, bfields@xxxxxxxxxxxx > <bfields@xxxxxxxxxxxx> wrote: > > On Fri, Jun 01, 2018 at 04:43:51PM +0200, Miklos Szeredi wrote: > >> Look at ovl_permission(), I think it pretty clearly describes this model. > > > > Thanks! Uh, so generic_permission is the thing that just does the usual > > mode/acl checks on the in-core inode, and inode_permission is the one > > that also calls into the filesystem? > > Right. > > > But I'm still a little confused--if I'm reading right, "realinode" is > > the lower inode before copyup, and the upper inode after, so can't > > inode_permission(realinode, mask) return different results before and > > after copyup? > > Theoretically, yes. Not in any sane setup, though. If root squashing is enabled and you mount as root, then it will change. That's not an unlikely case, it's pretty much the default. --b. > > The inode_permission() checks on realinode are for making sure the > mounter cannot gain undue privileges (will be especially important > with userns mounts). -- To unsubscribe from this list: send the line "unsubscribe linux-unionfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
