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>
---
v3: split out static helper, switch from bitfield to flags field (leaving
two bytes for future use, u16 should be enough for flags for this ioctl)
block/sed-opal.c | 39 +++++++++++++++++++++++++++++++++++
include/uapi/linux/sed-opal.h | 8 ++++++-
2 files changed, 46 insertions(+), 1 deletion(-)
diff --git a/block/sed-opal.c b/block/sed-opal.c
index 9bdb833e5817..463873f61e01 100644
--- a/block/sed-opal.c
+++ b/block/sed-opal.c
@@ -2461,6 +2461,44 @@ static int __opal_set_mbr_done(struct opal_dev *dev, struct opal_key *key)
return execute_steps(dev, mbrdone_step, ARRAY_SIZE(mbrdone_step));
}
+static void opal_lock_check_for_saved_key(struct opal_dev *dev,
+ struct opal_lock_unlock *lk_unlk)
+{
+ struct opal_suspend_data *iter;
+
+ if (lk_unlk->l_state != OPAL_LK ||
+ lk_unlk->session.opal_key.key_len > 0)
+ return;
+
+ /*
+ * 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.
+ */
+ setup_opal_dev(dev);
+ list_for_each_entry(iter, &dev->unlk_lst, node) {
+ if ((iter->unlk.flags & OPAL_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;
+ }
+ }
+}
+
static int opal_lock_unlock(struct opal_dev *dev,
struct opal_lock_unlock *lk_unlk)
{
@@ -2470,6 +2508,7 @@ static int opal_lock_unlock(struct opal_dev *dev,
return -EINVAL;
mutex_lock(&dev->dev_lock);
+ opal_lock_check_for_saved_key(dev, lk_unlk);
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..1fed3c9294fc 100644
--- a/include/uapi/linux/sed-opal.h
+++ b/include/uapi/linux/sed-opal.h
@@ -44,6 +44,11 @@ enum opal_lock_state {
OPAL_LK = 0x04, /* 0100 */
};
+enum opal_lock_flags {
+ /* IOC_OPAL_SAVE will also store the provided key for locking */
+ OPAL_SAVE_FOR_LOCK = 0x01,
+};
+
struct opal_key {
__u8 lr;
__u8 key_len;
@@ -76,7 +81,8 @@ struct opal_user_lr_setup {
struct opal_lock_unlock {
struct opal_session_info session;
__u32 l_state;
- __u8 __align[4];
+ __u16 flags;
+ __u8 __align[2];
};
struct opal_new_pw {
--
2.35.1
