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

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Message-ID: <20250515064048.43b70b87@kernel.org>
Date: Thu, 15 May 2025 06:40:48 -0700
From: Jakub Kicinski <kuba@...nel.org>
To: Wojtek Wasko <wwasko@...dia.com>
Cc: richardcochran@...il.com, vadim.fedorenko@...ux.dev,
 netdev@...r.kernel.org
Subject: Re: [PATCH] ptp: Add sysfs attribute to show clock is safe to open
 RO

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.