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. Tested-by: Shivaprasad G Bhat <[email protected]> Reviewed-by: Ilpo Järvinen <[email protected]> Signed-off-by: Krzysztof Wilczyński <[email protected]> --- 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 2280b7edb41f..dac780597727 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -1596,6 +1596,9 @@ 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; -- 2.54.0
