thunderbolt: Add authorized value to the KOBJ_CHANGE uevent

For security reasons, 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@google.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

diff --git a/drivers/thunderbolt/switch.c b/drivers/thunderbolt/switch.c
index 83b1ef3d5d037527b243b5fced51946a91d27c57..bc91887f24c307d41fc70b6d15d91be260e6ccdb 100644 (file)
--- a/drivers/thunderbolt/switch.c
+++ b/drivers/thunderbolt/switch.c
@@ -1498,6 +1498,7 @@ static ssize_t authorized_show(struct device *dev,
 
 static int disapprove_switch(struct device *dev, void *not_used)
 {
+       char *envp[] = { "AUTHORIZED=0", NULL };
        struct tb_switch *sw;
 
        sw = tb_to_switch(dev);
@@ -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;
@@ -1522,7 +1523,9 @@ static int disapprove_switch(struct device *dev, void *not_used)
 
 static int tb_switch_set_authorized(struct tb_switch *sw, unsigned int val)
 {
+       char envp_string[13];
        int ret = -EINVAL;
+       char *envp[] = { envp_string, NULL };
 
        if (!mutex_trylock(&sw->tb->lock))
                return restart_syscall();
@@ -1559,8 +1562,12 @@ 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);
+               /*
+                * Notify status change to the userspace, informing the new
+                * value of /sys/bus/thunderbolt/devices/.../authorized.
+                */
+               sprintf(envp_string, "AUTHORIZED=%u", sw->authorized);
+               kobject_uevent_env(&sw->dev.kobj, KOBJ_CHANGE, envp);
        }
 
 unlock: