| Message ID | 20210724004043.2075819-1-rajatja@google.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [v2] thunderbolt: For dev authorization changes, include the actual event in udev change notification | expand |
Hi Rajat, On Fri, Jul 23, 2021 at 05:41:58PM -0700, Rajat Jain wrote: > (fixing the typo in the email ID for Greg). > > On Fri, Jul 23, 2021 at 5:40 PM Rajat Jain <rajatja@google.com> 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 Looking good, a couple of minor nits below. > > > > Signed-off-by: Rajat Jain <rajatja@google.com> > > --- > > 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 }; Can you move arrange this to be before sw, like: char *envp[] = { "AUTHORIZED=0", NULL }; struct tb_switch *sw; > > > > 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 }; Ditto. > > > > 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 > >
On Mon, Jul 26, 2021 at 6:40 AM Mika Westerberg <mika.westerberg@linux.intel.com> wrote: > > Hi Rajat, > > On Fri, Jul 23, 2021 at 05:41:58PM -0700, Rajat Jain wrote: > > (fixing the typo in the email ID for Greg). > > > > On Fri, Jul 23, 2021 at 5:40 PM Rajat Jain <rajatja@google.com> 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 > > Looking good, a couple of minor nits below. > > > > > > > Signed-off-by: Rajat Jain <rajatja@google.com> > > > --- > > > 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 }; > > Can you move arrange this to be before sw, like: Done. > > char *envp[] = { "AUTHORIZED=0", NULL }; > struct tb_switch *sw; > > > > > > > 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 }; > > Ditto. Done. I still needed to define envp_string before envp (because it is used in initialization). I sent out a v3 with these changes. Thanks, Rajat > > > > > > > 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 > > >
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:
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@google.com> --- drivers/thunderbolt/switch.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)