On Mon, Dec 30, 2019 at 12:29 AM Aleksa Sarai <cyphar@xxxxxxxxxx> wrote: > > On 2019-12-29, Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: > > On Sun, Dec 29, 2019 at 9:21 PM Aleksa Sarai <cyphar@xxxxxxxxxx> wrote: > > If allowing bind-mounts over symlinks is allowed (which I don't have a > problem with really), it just means we'll need a few more kernel pieces > to get this hardening to work. But these features would be useful > outside of the problems I'm dealing with (O_EMPTYPATH and some kind of > pidfd-based interface to grab the equivalent of /proc/self/exe and a few > other such magic-link targets). As one data point, I would use this ability in virtme: this would allow me to more reliably mount over /etc/resolve.conf even when it's a symlink. (Perhaps I should use overlayfs instead. Hmm.)
