On Tue, Feb 20, 2018 at 03:17:05PM -0800, Andrew Morton wrote: > On Mon, 19 Feb 2018 11:53:50 -0500 Waiman Long <longman@xxxxxxxxxx> wrote: > > > Even with clamped sysctl parameters, it is still not that straight > > forward to figure out the exact range of those parameters. One may > > try to write extreme parameter values to see if they get clamped. > > To make it easier, a warning with the expected range will now be > > printed in the kernel ring buffer when a clamped sysctl parameter > > receives an out of range value. > > This assumes that do_proc_dointvec_minmax_conv() and > do_proc_douintvec_minmax_conv() are only ever called by privileged > userspace. Because we mustn't give unprivileged applications a way to > spam the kernel logs. > > That's presumably true in the case of the caller you just added, but I > don't see what we can do to guarantee this in the future, so perhaps we > should add some permission check to the pr_warn()? Beyond what we do with sysctl_perm() on proc_sys_call_handler()? Luis
