[PATCHv3 2/2] nvme: validate cntlid during controller initialisation

[hare@suse.de (Hannes Reinecke)]

From: Hannes Reinecke <hare@suse.com>

The CNTLID value is required to be unique, and we do rely on this
for correct operation. So reject any controller for which a non-unique
CNTLID has been detected.

Signed-off-by: Hannes Reinecke <hare at suse.com>
---
 drivers/nvme/host/core.c | 32 ++++++++++++++++++++++++++++++--
 1 file changed, 30 insertions(+), 2 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index cd16d98d1f1a..dc74f7ba6f4a 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -2358,6 +2358,23 @@ static int nvme_active_ctrls(struct nvme_subsystem *subsys)
 	return count;
 }
 
+static bool nvme_duplicate_cntlid(struct nvme_subsystem *subsys,
+				  struct nvme_ctrl *ctrl)
+{
+	struct nvme_ctrl *tmp;
+	bool ret = false;
+
+	list_for_each_entry(tmp, &subsys->ctrls, subsys_entry) {
+		if (tmp == ctrl)
+			continue;
+		if (tmp->cntlid == ctrl->cntlid) {
+			ret = true;
+			break;
+		}
+	}
+	return ret;
+}
+
 static int nvme_init_subsystem(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
 {
 	struct nvme_subsystem *subsys, *found;
@@ -2411,6 +2428,7 @@ static int nvme_init_subsystem(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
 
 		__nvme_release_subsystem(subsys);
 		subsys = found;
+		ret = 0;
 	} else {
 		ret = device_add(&subsys->dev);
 		if (ret) {
@@ -2434,10 +2452,20 @@ static int nvme_init_subsystem(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
 	}
 
 	mutex_lock(&subsys->lock);
-	list_add_tail(&ctrl->subsys_entry, &subsys->ctrls);
+	if (!nvme_duplicate_cntlid(subsys, ctrl))
+		list_add_tail(&ctrl->subsys_entry, &subsys->ctrls);
+	else {
+		dev_err(ctrl->device,
+			"Duplicate cntlid %u, rejecting\n",
+			ctrl->cntlid);
+		ctrl->subsys = NULL;
+		sysfs_remove_link(&subsys->dev.kobj, dev_name(ctrl->device));
+		nvme_put_subsystem(subsys);
+		ret = -EINVAL;
+	}
 	mutex_unlock(&subsys->lock);
 
-	return 0;
+	return ret;
 
 out_unlock:
 	mutex_unlock(&nvme_subsystems_lock);
-- 
2.16.4