linux-kernel - Re: [PATCH] PCI: Make d3cold_allowed sysfs attribute read only

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20231003094407.GG3208943@black.fi.intel.com>
Date:   Tue, 3 Oct 2023 12:44:07 +0300
From:   Mika Westerberg <mika.westerberg@...ux.intel.com>
To:     Mario Limonciello <mario.limonciello@....com>
Cc:     bhelgaas@...gle.com, lukas@...ner.de, linux-kernel@...r.kernel.org,
        linux-pci@...r.kernel.org
Subject: Re: [PATCH] PCI: Make d3cold_allowed sysfs attribute read only

On Mon, Oct 02, 2023 at 01:10:25PM -0500, Mario Limonciello wrote:
> Before d3cold was stable userspace was allowed to influence the kernel's
> decision of whether to enable d3cold for a device by a sysfs file
> `d3cold_allowed`.  This potentially allows userspace to break the suspend
> for the system.
> 
> For debugging purposes `pci_port_pm=` can be used to control whether
> a PCI port will go into D3cold and runtime PM can be turned off by
> sysfs on PCI end points.
> 
> Change the sysfs attribute to read-only and simplify the internal kernel
> logic to avoid needing to store the userspace request.

I wonder if this ends up breaking some userspace apps? Not objecting
though, just wanted to mention ;-)

One thing we could do is to taint the kernel or log a warning if
userspace touches this but allow it to do so.