block: sed-opal: Add ioctl to return device status

Provide a mechanism to retrieve basic status information about
the device, including the "supported" flag indicating whether
SED-OPAL is supported. The information returned is from the various
feature descriptors received during the discovery0 step, and so
this ioctl does nothing more than perform the discovery0 step
and then save the information received. See "struct opal_status"
and OPAL_FL_* bits for the status information currently returned.

This is necessary to be able to check whether a device is OPAL
enabled, set up, locked or unlocked from userspace programs
like systemd-cryptsetup and libcryptsetup. Right now we just
have to assume the user 'knows' or blindly attempt setup/lock/unlock
operations.

Signed-off-by: Douglas Miller <dougmill@linux.vnet.ibm.com>
Tested-by: Luca Boccassi <bluca@debian.org>
Reviewed-by: Scott Bauer <sbauer@plzdonthack.me>
Acked-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Link: https://lore.kernel.org/r/20220816140713.84893-1-luca.boccassi@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 77 insertions, 12 deletions

diff --git a/block/sed-opal.c b/block/sed-opal.c
index 9700197000f2..2c5327a0543a 100644
--- a/block/sed-opal.c
+++ b/block/sed-opal.c
@@ -74,8 +74,7 @@ struct parsed_resp {
 };
 
 struct opal_dev {
-	bool supported;
-	bool mbr_enabled;
+	u32 flags;
 
 	void *data;
 	sec_send_recv *send_recv;
@@ -280,6 +279,30 @@ static bool check_tper(const void *data)
 	return true;
 }
 
+static bool check_lcksuppt(const void *data)
+{
+	const struct d0_locking_features *lfeat = data;
+	u8 sup_feat = lfeat->supported_features;
+
+	return !!(sup_feat & LOCKING_SUPPORTED_MASK);
+}
+
+static bool check_lckenabled(const void *data)
+{
+	const struct d0_locking_features *lfeat = data;
+	u8 sup_feat = lfeat->supported_features;
+
+	return !!(sup_feat & LOCKING_ENABLED_MASK);
+}
+
+static bool check_locked(const void *data)
+{
+	const struct d0_locking_features *lfeat = data;
+	u8 sup_feat = lfeat->supported_features;
+
+	return !!(sup_feat & LOCKED_MASK);
+}
+
 static bool check_mbrenabled(const void *data)
 {
 	const struct d0_locking_features *lfeat = data;
@@ -288,6 +311,14 @@ static bool check_mbrenabled(const void *data)
 	return !!(sup_feat & MBR_ENABLED_MASK);
 }
 
+static bool check_mbrdone(const void *data)
+{
+	const struct d0_locking_features *lfeat = data;
+	u8 sup_feat = lfeat->supported_features;
+
+	return !!(sup_feat & MBR_DONE_MASK);
+}
+
 static bool check_sum(const void *data)
 {
 	const struct d0_single_user_mode *sum = data;
@@ -435,7 +466,7 @@ static int opal_discovery0_end(struct opal_dev *dev)
 	u32 hlen = be32_to_cpu(hdr->length);
 
 	print_buffer(dev->resp, hlen);
-	dev->mbr_enabled = false;
+	dev->flags &= OPAL_FL_SUPPORTED;
 
 	if (hlen > IO_BUFFER_LENGTH - sizeof(*hdr)) {
 		pr_debug("Discovery length overflows buffer (%zu+%u)/%u\n",
@@ -461,7 +492,16 @@ static int opal_discovery0_end(struct opal_dev *dev)
 			check_geometry(dev, body);
 			break;
 		case FC_LOCKING:
-			dev->mbr_enabled = check_mbrenabled(body->features);
+			if (check_lcksuppt(body->features))
+				dev->flags |= OPAL_FL_LOCKING_SUPPORTED;
+			if (check_lckenabled(body->features))
+				dev->flags |= OPAL_FL_LOCKING_ENABLED;
+			if (check_locked(body->features))
+				dev->flags |= OPAL_FL_LOCKED;
+			if (check_mbrenabled(body->features))
+				dev->flags |= OPAL_FL_MBR_ENABLED;
+			if (check_mbrdone(body->features))
+				dev->flags |= OPAL_FL_MBR_DONE;
 			break;
 		case FC_ENTERPRISE:
 		case FC_DATASTORE:
@@ -2109,7 +2149,8 @@ static int check_opal_support(struct opal_dev *dev)
 	mutex_lock(&dev->dev_lock);
 	setup_opal_dev(dev);
 	ret = opal_discovery0_step(dev);
-	dev->supported = !ret;
+	if (!ret)
+		dev->flags |= OPAL_FL_SUPPORTED;
 	mutex_unlock(&dev->dev_lock);
 
 	return ret;
@@ -2148,6 +2189,7 @@ struct opal_dev *init_opal_dev(void *data, sec_send_recv *send_recv)
 
 	INIT_LIST_HEAD(&dev->unlk_lst);
 	mutex_init(&dev->dev_lock);
+	dev->flags = 0;
 	dev->data = data;
 	dev->send_recv = send_recv;
 	if (check_opal_support(dev) != 0) {
@@ -2528,7 +2570,7 @@ bool opal_unlock_from_suspend(struct opal_dev *dev)
 	if (!dev)
 		return false;
 
-	if (!dev->supported)
+	if (!(dev->flags & OPAL_FL_SUPPORTED))
 		return false;
 
 	mutex_lock(&dev->dev_lock);
@@ -2546,7 +2588,7 @@ bool opal_unlock_from_suspend(struct opal_dev *dev)
 			was_failure = true;
 		}
 
-		if (dev->mbr_enabled) {
+		if (dev->flags & OPAL_FL_MBR_ENABLED) {
 			ret = __opal_set_mbr_done(dev, &suspend->unlk.session.opal_key);
 			if (ret)
 				pr_debug("Failed to set MBR Done in S3 resume\n");
@@ -2620,6 +2662,23 @@ static int opal_generic_read_write_table(struct opal_dev *dev,
 	return ret;
 }
 
+static int opal_get_status(struct opal_dev *dev, void __user *data)
+{
+	struct opal_status sts = {0};
+
+	/*
+	 * check_opal_support() error is not fatal,
+	 * !dev->supported is a valid condition
+	 */
+	if (!check_opal_support(dev))
+		sts.flags = dev->flags;
+	if (copy_to_user(data, &sts, sizeof(sts))) {
+		pr_debug("Error copying status to userspace\n");
+		return -EFAULT;
+	}
+	return 0;
+}
+
 int sed_ioctl(struct opal_dev *dev, unsigned int cmd, void __user *arg)
 {
 	void *p;
@@ -2629,12 +2688,14 @@ int sed_ioctl(struct opal_dev *dev, unsigned int cmd, void __user *arg)
 		return -EACCES;
 	if (!dev)
 		return -ENOTSUPP;
-	if (!dev->supported)
+	if (!(dev->flags & OPAL_FL_SUPPORTED))
 		return -ENOTSUPP;
 
-	p = memdup_user(arg, _IOC_SIZE(cmd));
-	if (IS_ERR(p))
-		return PTR_ERR(p);
+	if (cmd & IOC_IN) {
+		p = memdup_user(arg, _IOC_SIZE(cmd));
+		if (IS_ERR(p))
+			return PTR_ERR(p);
+	}
 
 	switch (cmd) {
 	case IOC_OPAL_SAVE:
@@ -2685,11 +2746,15 @@ int sed_ioctl(struct opal_dev *dev, unsigned int cmd, void __user *arg)
 	case IOC_OPAL_GENERIC_TABLE_RW:
 		ret = opal_generic_read_write_table(dev, p);
 		break;
+	case IOC_OPAL_GET_STATUS:
+		ret = opal_get_status(dev, arg);
+		break;
 	default:
 		break;
 	}
 
-	kfree(p);
+	if (cmd & IOC_IN)
+		kfree(p);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(sed_ioctl);