Re: [PATCH 04/20] PCI/sysfs: Add CAP_SYS_ADMIN check to __resource_resize_store()

Ilpo Järvinen
2026-04-10T10:19:10Z

[-- Attachment #1: Type: text/plain, Size: 1251 bytes --]

On Fri, 10 Apr 2026, Krzysztof Wilczyński wrote:

> Currently, the __resource_resize_store() allows writing to the
> resourceN_resize sysfs attribute to change a BAR's size without
> checking for capabilities, currently relying only on the file
> access check.
>
> Resizing a BAR modifies PCI device configuration and can disrupt
> active drivers. After the upcoming conversion to static attributes,
> it will also trigger resource file updates via sysfs_update_groups().
>
> Thus, add a CAP_SYS_ADMIN check to prevent unprivileged users from
> performing BAR resize operations.
>
> Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
> ---
> drivers/pci/pci-sysfs.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
> index ac4e7c516e78..6b8c8e62f68a 100644
> --- a/drivers/pci/pci-sysfs.c
> +++ b/drivers/pci/pci-sysfs.c
> @@ -1619,6 +1619,9 @@ static ssize_t __resource_resize_store(struct device *dev, int n,
> int ret;
> u16 cmd;
>
> + if (!capable(CAP_SYS_ADMIN))
> + return -EPERM;
> +
> if (kstrtoul(buf, 0, &size) < 0)
> return -EINVAL;
>
>

Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

--
i.