(fixing the typo in the email ID for Greg).
On Fri, Jul 23, 2021 at 5:40 PM Rajat Jain <rajatja@xxxxxxxxxx> wrote:
>
> For security, we would like to monitor and track when the thunderbolt
> devices are authorized and deauthorized (i.e. when the thunderbolt sysfs
> "authorized" attribute changes). Currently the userspace gets a udev
> change notification when there is a change, but the state may have
> changed (again) by the time we look at the authorized attribute in
> sysfs. So an authorization event may go unnoticed. Thus make it easier
> by informing the actual change (new value of authorized attribute) in
> the udev change notification.
>
> The change is included as a key value "authorized=<val>" where <val>
> is the new value of sysfs attribute "authorized", and is described at
> Documentation/ABI/testing/sysfs-bus-thunderbolt under
> /sys/bus/thunderbolt/devices/.../authorized
>
> Signed-off-by: Rajat Jain <rajatja@xxxxxxxxxx>
> ---
> drivers/thunderbolt/switch.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/thunderbolt/switch.c b/drivers/thunderbolt/switch.c
> index 83b1ef3d5d03..382128dfbdee 100644
> --- a/drivers/thunderbolt/switch.c
> +++ b/drivers/thunderbolt/switch.c
> @@ -1499,6 +1499,7 @@ static ssize_t authorized_show(struct device *dev,
> static int disapprove_switch(struct device *dev, void *not_used)
> {
> struct tb_switch *sw;
> + char *envp[] = { "AUTHORIZED=0", NULL };
>
> sw = tb_to_switch(dev);
> if (sw && sw->authorized) {
> @@ -1514,7 +1515,7 @@ static int disapprove_switch(struct device *dev, void *not_used)
> return ret;
>
> sw->authorized = 0;
> - kobject_uevent(&sw->dev.kobj, KOBJ_CHANGE);
> + kobject_uevent_env(&sw->dev.kobj, KOBJ_CHANGE, envp);
> }
>
> return 0;
> @@ -1523,6 +1524,8 @@ static int disapprove_switch(struct device *dev, void *not_used)
> static int tb_switch_set_authorized(struct tb_switch *sw, unsigned int val)
> {
> int ret = -EINVAL;
> + char envp_string[13];
> + char *envp[] = { envp_string, NULL };
>
> if (!mutex_trylock(&sw->tb->lock))
> return restart_syscall();
> @@ -1560,7 +1563,8 @@ static int tb_switch_set_authorized(struct tb_switch *sw, unsigned int val)
> if (!ret) {
> sw->authorized = val;
> /* Notify status change to the userspace */
> - kobject_uevent(&sw->dev.kobj, KOBJ_CHANGE);
> + sprintf(envp_string, "AUTHORIZED=%u", sw->authorized);
> + kobject_uevent_env(&sw->dev.kobj, KOBJ_CHANGE, envp);
> }
>
> unlock:
> --
> 2.32.0.432.gabb21c7263-goog
>
