On Mon, Dec 30, 2019 at 12:29 AM Aleksa Sarai cyphar@cyphar.com wrote:
On 2019-12-29, Linus Torvalds torvalds@linux-foundation.org wrote:
On Sun, Dec 29, 2019 at 9:21 PM Aleksa Sarai cyphar@cyphar.com 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.)