From: Luca Boccassi <bluca@xxxxxxxxxx>
Usually when closing a crypto device (eg: dm-crypt with LUKS) the
volume key is not required, as it requires root privileges anyway, and
root can deny access to a disk in many ways regardless. Requiring the
volume key to lock the device is a peculiarity of the OPAL
specification.
Given we might already have saved the key if the user requested it via
the 'IOC_OPAL_SAVE' ioctl, we can use that key to lock the device if no
key was provided here and the locking range matches, and the user sets
the appropriate flag with 'IOC_OPAL_SAVE'. This allows integrating OPAL
with tools and libraries that are used to the common behaviour and do
not ask for the volume key when closing a device.
Callers can always pass a non-zero key and it will be used regardless,
as before.
Suggested-by: Štěpán Horáček <stepan.horacek@xxxxxxxxx>
Signed-off-by: Luca Boccassi <bluca@xxxxxxxxxx>
---
v2: break on 80chr for optimal rendering on 1970s green monochrome monitors
make the new functionality dependent on a new flag that has to be
passed to IOC_OPAL_SAVE, using reserved bits in its ioctl struct
block/sed-opal.c | 32 ++++++++++++++++++++++++++++++++
include/uapi/linux/sed-opal.h | 3 ++-
2 files changed, 34 insertions(+), 1 deletion(-)
diff --git a/block/sed-opal.c b/block/sed-opal.c
index 9bdb833e5817..3a81754a0fdf 100644
--- a/block/sed-opal.c
+++ b/block/sed-opal.c
@@ -2470,6 +2470,38 @@ static int opal_lock_unlock(struct opal_dev *dev,
return -EINVAL;
mutex_lock(&dev->dev_lock);
+
+ /*
+ * Usually when closing a crypto device (eg: dm-crypt with LUKS) the volume
+ * key is not required, as it requires root privileges anyway, and root can
+ * deny access to a disk in many ways regardless. Requiring the volume key
+ * to lock the device is a peculiarity of the OPAL specification.
+ * Given we might already have saved the key if the user requested it via
+ * the 'IOC_OPAL_SAVE' ioctl, we can use that key to lock the device if no
+ * key was provided here, the locking range matches and the appropriate
+ * flag was passed with 'IOC_OPAL_SAVE'. This allows integrating OPAL with
+ * tools and libraries that are used to the common behaviour and do not ask
+ * for the volume key when closing a device.
+ */
+ if (lk_unlk->l_state == OPAL_LK &&
+ lk_unlk->session.opal_key.key_len == 0) {
+ struct opal_suspend_data *iter;
+
+ setup_opal_dev(dev);
+ list_for_each_entry(iter, &dev->unlk_lst, node) {
+ if (iter->unlk.save_for_lock &&
+ iter->lr == lk_unlk->session.opal_key.lr &&
+ iter->unlk.session.opal_key.key_len > 0) {
+ lk_unlk->session.opal_key.key_len =
+ iter->unlk.session.opal_key.key_len;
+ memcpy(lk_unlk->session.opal_key.key,
+ iter->unlk.session.opal_key.key,
+ iter->unlk.session.opal_key.key_len);
+ break;
+ }
+ }
+ }
+
ret = __opal_lock_unlock(dev, lk_unlk);
mutex_unlock(&dev->dev_lock);
diff --git a/include/uapi/linux/sed-opal.h b/include/uapi/linux/sed-opal.h
index 2573772e2fb3..fa604fb07f50 100644
--- a/include/uapi/linux/sed-opal.h
+++ b/include/uapi/linux/sed-opal.h
@@ -76,7 +76,8 @@ struct opal_user_lr_setup {
struct opal_lock_unlock {
struct opal_session_info session;
__u32 l_state;
- __u8 __align[4];
+ __u8 save_for_lock:1; /* if in IOC_OPAL_SAVE will also use key to lock */
+ __u8 __align[3];
};
struct opal_new_pw {
--
2.35.1
