On 19/03/2021 19:54, Mickaël Salaün wrote: > > On 19/03/2021 19:03, Kees Cook wrote: >> On Tue, Mar 16, 2021 at 09:42:52PM +0100, Mickaël Salaün wrote: >>> From: Mickaël Salaün <mic@xxxxxxxxxxxxxxxxxxx> [...] >> >>> [...] >>> +Special filesystems >>> +------------------- >>> + >>> +Access to regular files and directories can be restricted by Landlock, >>> +according to the handled accesses of a ruleset. However, files that do not >>> +come from a user-visible filesystem (e.g. pipe, socket), but can still be >>> +accessed through /proc/self/fd/, cannot currently be restricted. Likewise, >>> +some special kernel filesystems such as nsfs, which can be accessed through >>> +/proc/self/ns/, cannot currently be restricted. For now, these kind of special >>> +paths are then always allowed. Future Landlock evolutions will enable to >>> +restrict such paths with dedicated ruleset flags. >> >> With this series, can /proc (at the top level) be blocked? (i.e. can a >> landlock user avoid the weirdness by making /proc/$pid/ unavailable?) > > /proc can be blocked, but not /proc/*/ns/* because of disconnected > roots. I plan to address this. It is important to note that access to sensitive /proc files such as ns/* and fd/* are automatically restricted according to domain hierarchies. I'll add this detail to the documentation. :)
