On Fri, Apr 8, 2016 at 11:51 AM, Eric W. Biederman <ebied...@xmission.com> wrote: > > Given that concern under the rule we don't break userspace we have to > check the permissions of /dev/pts/ptmx when we are creating a new pty, > on a instance of devpts that was created with newinstance.
The rule is that we don't break existing installations. If somebody has root and installs a "ptmx" node in an existing mount space next to a pts subdirectory, that's not a security issue, nor is it going to break any existing installation. The whole point of the patch is that yes, we change semantics. A change of semantics means that people will see situations where the behavior is different. But that's not "breaking user space", that's just "ok, you can see a difference". Linus