Re: [PATCH] ptp: Add sysfs attribute to show clock is safe to open RO

[Jakub Kicinski <kuba@kernel.org>]

On Wed, 14 May 2025 17:36:21 +0300 Wojtek Wasko wrote:
> Recent patches introduced in 6.15 implement permissions checks for PTP
> clocks. Prior to those, a process with readonly access could modify the
> state of PTP devices, in particular the generation and consumption of
> PPS signals.
> 
> Userspace (e.g. udev) managing the ownership and permissions of device
> nodes lacks information as to whether kernel implements the necessary
> security checks and whether it is safe to expose readonly access to
> PTP devices to unprivileged users. Kernel version checks are cumbersome
> and prone to failure, especially if backports are considered [1].
> 
> Add a readonly sysfs attribute to PTP clocks, "ro_safe", backed by a
> static string.

Please CC Greg on v2, maybe we're missing a trick.
Also remember to add a signoff.